centre of advanced faculty training in plant pathology

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Proceedings of the 24th

Training

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PREFACE

Human sufferings and epidemics of plant diseases have gone hand in hand since the earliest history of

man. History illustrates that plant diseases can have a significant effect on human society. Even today,

catastrophic plant disease exacerbates the current deficit of food supply in which at least 800 million people are

inadequately fed. Indian agriculture, basically characterized as a means of subsistence, is changing fast as per

market demands, both domestic and international. Modern high input mono-cropping based intensive agriculture

has resulted in loss of biodiversity (both flora and fauna), out-breaks of pests and diseases, degradation of soil

and water, which has ultimately led to decline in agricultural production and productivity. Climatic changes are

becoming a major factor in the present scenario.

The importance of plant diseases in terms of causing restrictions to global food production is well

understood. The analysis of the potential impacts of climate change on plant diseases is therefore essential for the

adoption of adaptation measures, as well as for the development of resistant cultivars, new control methods or

adapted techniques, in order to avoid more serious losses. Accelerated climate change affects components of

complex biological interactions differentially, often causing changes that are difficult to predict. Crop yield and

quality are affected by climate change directly, and indirectly, through diseases that themselves will change but

remain important.

The 21-day training under Center of Advanced Faculty Training in Plant Pathology envisaged to address

certain core issues that unravel, address or supplement strategies that are either in demand or are in vogue for

sustaining food productivity in the country taking into account the newer threats posed by changing productions

systems and climatic aberrations. It was also intended to address proactive and responsive communication

strategies to enable effective implementation of both the technologies already on the shelf, and those that will

flow from future research. Excellent response was received from all over India for participation in this training.

Twenty participants representing nine states, who actively participated in the programme, were exposed to the

recent advances made towards Climate change, precision agriculture and innovative disease control strategies

through series of lectures, practical and field visits.

We are grateful to the ICAR for sponsoring this 23rd

advanced training programme in series, and the 2nd

under the banner of the newly created Centre of Advanced Faculty Training in Plant Pathology at Pantnagar .

We are highly grateful to Prof. B.S. Bisht, Vice-Chancellor for his constant support, guidance and encouragement

in making the training a great success. We like to put on record the help and guidance received from Dr. S.K.

Saini, Dean Agriculture and Dr. J.P. Pandey, Director, Experiment Station in the successful conduct of training

programme. We sincerely acknowledge the services of our guest speakers Dr. Rakesh Pandey, CIMAP, Lucknow,

Dr. Y.P. Singh, FRI, Dehradun; Dr. D.K. Chakrabarti, NDUAT, Faizabad, Dr. Roopam Kapoor, Delhi

University, Dr. K.S. Hooda, DMR, Delhi and Dr. S.L. Chaudhary, MPUAT, Udaipur. We would like to place on

record the help and logistic support received from Dr. M.C. Nautiyal, Dean, Hill Campus, Ranichauri and his

team of scientists for delivering lectures during exposure visit of participants. Several scientists from various

departments such as Agronomy, Soil Science, Entomology, Genetics and Plant Breeding, Agriculture

Communication, Agrometeorology, Biological Science, Microbiology, Molecular Biology & Genetic Engineering,

Chemistry, Physics, Environmental Science, Farm Machinery & Power, Irrigation and Drainage Engineering,

Vet. Anatomy and the University library in addition to the Plant Pathology rendered all possible help and

delivered scientific lectures and designed practical exposure to the participants. We acknowledge their

contributions with utmost gratitude and sincerity.

Pantnagar

April 11, 2011

Dr. R.P. Singh

Course Coordinator

Dr. J. Kumar

Director, CAFT

CONTENTS

Sl. No. Title Speaker Page

Welcome Address Dr. J. Kumar i-iii

Inaugural Address Prof. B.S. Bisht i-iii

1. Department of Plant Pathology Dr. J. Kumar 1-23

2. Climate Change and Impacts on Plant Diseases Dr. H.S. Tripathi 24-25

3. Climate Change and Food Security: Enhancing

Adaptation Capabilities as a Response to Global

Warming in Fragile Mountain Ecosystems

Dr. Vir Singh 26-39

4. Disease Management in Precision Farming Dr. V.S. Pundhir 40-42

5. Climate Change and Mitigatory Measures with

Reference to Hill

Dr. Uma Melkania 43-47

6. Climate Change and Plant Diseases Dr. N.S. Murty 48-52

7. Impact of Agricultural Intensification on Carbon

Sequestration and Soil Health

Dr. K.P. Raverkar 53-62

8. Seed Health Testing: Retrospective and

Perspectives

Dr. K. Vishunavat 63-67

9. Communication Skills in Teaching Dr. B. Kumar 68-72

10. Climate Change in Social Perspective Dr. R.P. Singh 73-81

11. Resource Conservation Techniques in Plant Health

and Disease Management: No Till or Reduced Till

Cropping System

Dr. K.P. Singh 82-86

12. Role of Eco-friendly Approaches in Integrated

Pests and Disease Management

Dr. Ruchira Tewari 87-94

13. Advances in Electron Microscopy and application in

Plant Pathology

Dr. Balvinder Singh 95-104

14. Plant Disease Forecasting (Late Blight Forecasting) Dr. V.S. Pundhir 105-110

15. Recent Molecular Biology Tools for Rhizospheric

Community Analysis for Effective Introduction of

Bioagents Application for Organic Agricultural

Practices

Dr. A.K. Gaur 111-115

16. GIS Application in Precision Farming and Plant

Disease Management

Dr. A.K. Agnihotri 116-121

17. Nanotechnology: A Modern Tool for Precision

Farming


18. Knowledge Transfer: Issues and Expectations Dr. K.P. Singh 127-131

19. Importance of Multitrophic Interactions for

Sucessful Biocontrol of Plant Parasitic Nematodes

with Fungal and Bacterial Antagonists

Dr. Rakesh Pandey 132-137

i

20. Biological Control of Frost Injury: Role of Ice

Nucleating Bacteria

Dr. S.C. Saxena 138-144

21. Characterization of Pathogen Population and

Resistance Management: A Case Study of Rice

Blast Pathosystem

Dr. J. Kumar 145-149

22. Visit to Automatic Weather Station and

Meteorological Observatory at CRC

Dr. H.S. Kushwaha 150-157

23. Toxicological Investigations on the Emerging Pest

Problems in the Important Crops

Dr. S.N. Tiwari 158-160

24. HPLC – An Important Tool for assessment of

Fungicide residues in Crops

Dr. Anjana

Srivastava

161-164

25. Novelties in Mango Malformation Research Dr. D.K. Chakrabarti 165-168

26. Precision Agriculture for Higher Productivity and

Profitability

Dr. Rajeew Kumar 169-175

27. Overcoming Nutritional Deficiencies and Toxicities

in Crop Plants

Dr. P.C. Srivastava 176-177

28. Precision in Soil and Nutrient Management with

Special Reference to Subsoil Health

Dr. T.C. Thakur 178-182

29. Bio-control Strategies for the Management of

Threatening Diseases by Use of Trichoderma spp

Dr. Najam Waris

Zaidi

183-191

30. Environmental Factors Influencing Ascospore

Viability, Conidium Production, Dissemination, and

Germination of V. inaequalis


31. Carbon Sequestration: Bamboo-Mycorrhizae Dr. Y.P. Singh 197-213

32. Plant Healthcare for Resource Poor Farmers –

Technologies for Disease Management in Low

Input Systems

Dr. J. Kumar 214-220

33. Metagenomics-A Tool for Identification and

Characterization of Uncultivated Microbial Diversity

Dr. Reeta Goel 221-224

34. Effect of Climate Change on Plant-Pathogen

Interactions

Dr. Rupam Kapoor 225-228

35. Soil Solarization and Its Application in Plant

Disease Management

Dr. Yogendra Singh 229-233

36. Precision Farming with Special Relevance to

Irrigation and Fertigation

Dr. P. K. Singh 234-240

37. Induced Systemic Resistance against White Rust of

Mustard by Pre-or Coinoculation with an

Incompatible Isolate

Dr. R.P. Awasthi 241-249

38. Multilines and Cultivar Mixtures for Plant Disease

Management

Dr. P.K. Shrotria

250-257

ii

39. SAS: An Introduction and its Applications Dr. S.B. Singh 258-265

40. Innovations in Agrochemical Formulation

Technology for Safety and Efficacy

Dr. Shishir Tandon

266-275

41. Innovations in Agro-chemical Application

Technology for Safety and Efficacy

Dr. T.P. Singh 276-288

42. Wheat Rusts: New Virulences threatening Global

Wheat Production and Strategies to Manage


43. Plant Diseases in Changing Climate Dr. K.S. Hooda 297-303

44. Evaluation and Selection of Promising Trichoderma

Isolates For the Management of Soil Borne Fungal

Plant Pathogens

Dr. A.K. Tewari 304-307

45. Major Seed Pieces Transmissible Diseases of

Sugarcane and their Management by Three Tier

Seed Programme

Dr. R.K. Sahu 308-314

46. Biolog: Microbial Identification System Dr. R.P. Singh 315-316

47. Role of Plant Genetic Resources in Plant Disease

Management

Dr. R.K. Khulbe 317-319

48. Disease Management under Protected Cultivation Dr. R.P Singh 320-322

49. Engineering Resistance against Biotic Stress

Affecting Horticultural and Field Crop

Dr. N.K. Singh 323-327

Valedictory Address Vice-Chancellor i-ii

Annexure- I (Committee members) ---

i

Annexure- II (List of Participants) ---

i-iii

Annexure- III (List of Speakers) ---

i-ii

Annexure- IV (Training Course Schedule) ---

i-iv

iii

WELCOME ADDRESS by

Dr. J. Kumar Director CAFT

Prof. & Head, Plant Pathology, College of Agriculture

G.B. Pant University of Agriculture & Technology, Pantnagar- 263 145

on

March 25, 2011

Good morning and welcome to the

Inaugural Session of the 24th CAFT training on

“Climate change, Precision agriculture and

innovative disease control strategies”.

Hon’ble Chief guest, Dr. B. S. Bisht, the

Vice-Chancellor; Dr. J.P. Pandey, Director

Experiment Station and Dr. S.C. Saxena,

honorary professor, Dr. R.P. Singh, Course

Coordinator of the present training, Deans and

Directors, Head of Departments, Senior faculty

members, Colleagues, Staff members, the

trainees from different universities, Students,

Press & Media, Ladies & Gentle men.

At the outset, on behalf of faculty of Plant

Pathology and on my own behalf and also as

officiating Dean, College of Agriculture, it is a

pleasure in welcoming honorable Vice-

Chancellor, Dr. B.S. Bisht, who is known for his

immense energy, strong integrity and

commitment. Dr. Bisht, an alumni of this

University, has had a long distinguished

professional career in various capacities in the

country before joining ICAR where he was

responsible for designing, implementing and

monitoring human resource development

programmes towards academic excellence and

R&D. Dr. Bisht is a big support and source of

inspiration for the pursuance of research and

academics in this Great University as well. You

have consented to grace this occasion despite

your very hectic schedule of work, we are all very

grateful to you, Sir.

It is a pleasure in welcoming Dr. J. P.

Pandey, the Director of Research who has been

very successfully coordinating and leading a very

diverse research prograame in the university. We

all members of Plant Pathology faculty welcome

you.

I would also like to welcome Dr. S.C.

Saxena, the senior most person in the College

and a honorary professor in the Department of

Plant Pathology. Dr. Saxena is the First

Generation Staff in the Department as well as

the College and is an appropriate interface to the

younger generations coming to the Department.

I would also like to welcome my

colleague Dr. R.P. Singh, the Course

Coordinator of this CAFT training.

I welcome all the Deans and Directors

who are present here in the hall. They have

spared their valuable time to grace this occasion.

The Heads and faculty members of

various departments have also responded to our

request and are present in the hall. I welcome all

of you to the function.

The participants of the training from

different universities have traveled a long

distance to reach Pantnagar. At Pantnagar you

may miss the comfort and attractions of big cities

but the warmth of academic that exists at this

i

place and a very exhaustive work that awaits you

should keep you engrossed and compensate for

any logistic inadequacies. I welcome you all and

assure you a comfortable stay within our means.

In the last, but not the least, I welcome all

our students and staff, press and media and

others who are present in the hall and made the

arrangements for this inaugural session.

Ladies and gentlemen, the department of

Plant Pathology was created and accredited by

ICAR in 1961 and ever since the Department has

had a strong commitment to, and history of,

sound education, research and extension in

Plant Pathology. Dr. Y.L.Nene was the first

Head of the Department. Under his capable

leadership, the department expanded to include

many dedicated and extraordinary faculty

members including Dr. R.S. Singh and Dr.

Mukhopadhyay whose programmes made the

Department the recognized leader in the country.

The next generation of faculty members like the

first responded to the changing needs presented

by the modern agriculture. At present the

Department includes 9 professors, one senior

professor as Emeritus Scientist and one as honorary

professor, one honourary professor from INRA,

France, four Associate Professors and one Assistant

Professor with 14 technical and 11 supporting

staffs. The entire staff upholds the Department’s

commitment to education, basic and applied

research and extension.

The Department has a well-knit under

graduate (U.G.) and post graduate (P.G.)

programme with updated and modern course

curricula. It offers six U.G. and 20 P.G. courses.

A broad range of carefully designed courses

complimented by lectures in other Departments

appropriately address the academic needs of the

students. The great diversity in areas of

expertise and interests present in the

Department leads to diversity in thesis titles. So

far about 300 M.Sc. and 160 Ph.D. students

have earned degrees from the Department.

The Department is actively engaged in

the research work on both fundamental and

applied aspects in the domains of ecology of soil

borne plant pathogens, epidemiology and

forecasting, biological control and IPM including

small farms technologies, molecular diagnostics,

pathogen population biology, seed pathology,

fungicides, nematology, phytovirology,

phytobacteriology and biology & technology of

mushroom production.

The distinguished faculty of the

Department has brought in a number of national

and international research grants besides a

series of AICRPS. For a number of AICRPs

such as those of Maize, Oilseeds, Potato, and

Seeds the faculty members of the Department

render services as the Project Coordinators also.

Over the years, the trained and

accomplished faculty members as well as

students while addressing current issues in Plant

Pathology have won over 40 national and

international awards. Individual staff members

with in the department have long been

recognized for their leadership role in the science

of Plant Pathology. By way of their contributions

many faculty members of the Department have

earned International positions. Also a number of

faculty members have served as president, vice

presidents, and zonal president of several

professional societies

The Department has a unique distinction

of producing 56 books published by not only

Indian but also reputed international publishers.

This is besides a series of technical bulletins, lab

manuals, compendia and extension literature

that have also been prepared.

The Department, besides other fields,

has a strong set up in IPM and biocontrol and

has given a number of technologies for both

ii

plains and hills. The biocontrol lab in the

Department has been recognized as the referral

lab by DBT. In the recent past, Government of

India has declared the Biocontrol Lab in the

Department to perform the functions of the

`Central Insecticide Lab’ for biopesticides.

Similarly the Department also holds big strength

in mushroom research and trainings.

In view of quality of teaching, research

and extension work being carried out by the

department, ICAR upgraded the department to

the status of CAS in Plant Pathology in the year

1995 with the major mandate to train scientific

faculty from all over the country in important and

innovative areas of Plant Pathology. So far 23

trainings have been conducted wherein 478

scientists from 24 states have participated.

The topic of the present training under

CAFT is ‘Climate change, Precision agriculture

and innovative disease control strategies’. The

importance of the environment on the

development of plant diseases has been known

for over two thousand years. We know that the

environment can influence host plant growth and

susceptibility; pathogen reproduction, dispersal,

survival and activity; as well as host-pathogen

interaction. The classic disease triangle

establishes the conditions for disease

development, i.e. the interaction of a susceptible

host, a virulent pathogen and a favourable

environment. The intimate relationship between

the environment and diseases suggests that the

observed climate change will definitely cause

modifications in the current agriculture

production and phytosanitary scenario. The

impacts can be positive, negative or neutral,

since there can be a decrease, an increase or no

effect on the different pathosystems.

The importance of plant diseases in

terms of causing restrictions to global food

production is well understood. The analysis of

the potential impacts of climate change on plant

diseases is therefore essential for the adoption of

adaptation measures, as well as for the

development of resistant cultivars, new control

methods or adapted techniques, in order to avoid

more serious losses.

I will not go into the details about the

topic because it would be introduced to you more

appropriately by the Chief Guest.

However, I would like to mention that

Water-limiting environments, pest and diseases,

declining fertility, availability and degradation of

the soil resource are among key constraints to

increasing production and quality of food.

Climate change adds an extra layer of

complexity to an already complex agro-

ecological system. Intensive agriculture has been

a key component of green revolution. However

during last one decade or so, stasis in agriculture

production has been witnessed even after

replication of the same technology in different

regions. It is the time to redefine green revolution

by adding a component of precision agriculture

as well as improvised plant protection strategies

for sustainable agriculture. I would thus like to

extend my appreciations and special gratitude to

the Faculty of Plant Pathology for their

endorsement of the topic for the present CAFT

training.

Finally, I would like to thank our Vice-

Chancellor for allowing us to hold this training.

With these words I welcome you all and

assure a fruitful and comfortable stay to the

participants of this 24th training programme of

CAFT in Plant Pathology.

Thank you very much!

* * * * * * * * *

iii

Chairman’s Remarks by

Prof. B.S. Bisht

Vice-Chancellor


on

March 25, 2011

I consider it a great privilege to be

called upon to inaugurate the training course

“CLIMATE CHANGE, PRECESION

AGRICULTURE AND INNOVATIVE DISEASE

CONTROL STRATEGIES” being organized by

the Centre of Advanced Faculty Training

(CAFT) in Plant Pathology. I am delighted to

know that as many as 20 scientists from

different SAUs from various parts of the

country are participating in the training course.

I extend my warm welcome to you all.

I hope all of you know that Pantnagar

University has a distinguished record of

producing outstanding Plant Pathologists. The

accomplishments of this Department have been

outlined for you by the Director CAFT. However,

I would like to make a mention of two great plant

pathologists, Dr. Y.L. Nene and Dr. R.S. Singh,

who gave inspiring leadership to the Department

of Plant Pathology soon after the establishment

of the University on November 17, 1960. You

may well be aware that discovery of Khaira

diseases of rice due to zinc deficiency and its

control turned this Tarai into rice bowl of the

country. It is widely acknowledged as one of the

most important plant pathological discovery not

only in India but at the global level that had

maximum impact on farmers. You may also be

aware that Dr. R.S. Singh worked out basic

mechanisms for obtaining the disease control of

soil-borne plant diseases through organic

amendments, which is now becoming a reality

and way of organic farming. His books are

considered to be the milestones for being handy

text books both for under graduate and post

graduate students in Plant Pathology. This

department has to its credit number of research

publications and books that have been published

by some of the most reputed national and

international publishers from the USA and

Europe. The Department was rightly considered

by the ICAR for granting the status of Canter of

Advanced Studies in Plant Pathology in 1995,

and again, after the review, given the status of

Centre of Advanced Faculty Training in 2010. I

am aware that this Department is one of the very

few CAFTs in Plant Pathology in the country,

and thus has an important role not only in

training faculty from the country but also devising

improvised and sustainable methodologies for

plant disease management keeping in view the

alarming issue of food safety and food security in

21st century.

Dear participants, the FAO estimated

that 1.02 billion people went hungry in 2009,

the highest ever level of world hunger, mainly

as a result of declining investment in

agriculture. Land degradation, urban

expansion and conversion of crops and

croplands for non-food production will reduce

i

the total global cropping area by 8–20% by

2050. This fact, combined with water scarcity,

is already posing an alarming challenge to

increase food production by 50% to meet the

projected demand of the world’s population by

2050.

The World Food Summit of 1996

defined food security as existing “when all

people at all times have access to sufficient,

safe, nutritious food to maintain a healthy and

active life”. Therefore total food production

alone does not define food security since food

must be both safe and of appropriate nutritive

value.

Plant diseases are a major impediment

to the production and quality of important food

stuffs, and diseases that affect quality and

food safety. Pest and disease management

has played its role in doubling food production

in the last 40 years, but pathogens still

claim10–16%of the global harvest. In addition

to reducing yield, they are of particular concern

because of their direct impacts on human and

animal health.

Furthermore, food also has social

values. Food must be accessible and

affordable. This is dependent on production,

distribution and trading infrastructure and

mechanisms. All these factors may be affected

by climate change, and some are affected both

directly and indirectly through pest- and

pathogen-mediated changes that occur

because of climate change.

Climate change primarily mediates the

influence of plant diseases to affect

production, quality and safety of food.

Mycotoxins and pesticide residues in food are

among the top food safety concerns

associated with a changing climate.

Climate change and global warming

are the two momentous problems of the

present world. The earth’s climate has always

changed in response to changes in the

atmospheric and interacting factors but human

activities are now increasingly influencing

changes in global climate. Since 1750, global

emissions of radiatively active gases, including

CO2, coming from industry has increased

rapidly as a result of the use of carbon-based

fuels. Over the last 100 years, the global mean

temperature has increased by 0.74 0C and

atmospheric CO2 concentration has increased

from 280 ppm in 1750 to 368 ppm. in year

2000. Temperature is projected to increase by

3.40C and CO2 concentration to increase to

1250 ppm by 2095, accompanied by much

greater variability in climate and more extreme

weather related events.

Meeting this difficult challenge will be

made even harder if climate change melts

portions of the Himalayan glaciers to affect

25% of world cereal production in Asia by

influencing water availability and more frequent

floods affecting lives and livelihoods. These

changes will produce cropping changes which

will have implications for food availability,

directly or indirectly, through, consequent

changes in pathogen and pest incidence and

severity.

Plant pests and diseases could

potentially deprive humanity of up to 82% of

the attainable yield in the case of cotton and

over 50% for other major crops. Each year an

estimated 10–16% of global harvest is lost to

plant diseases. In financial terms, disease

ii

losses cost US $ 220 billion. There are

additional post harvest losses of 6–12%; these

are particularly high in developing tropical

countries that lack infrastructure. Plant

diseases can be far reaching and alter the

course of society and political history as

attested by the devastations from infamous

19th century Irish potato famine or the Bengal

famine.

In common with the past triumphs of

world agriculture that gave us the green

revolution to save millions from starvation, a

major component of the solution will have to

come from improved technology. This is a

timely reminder to all plant protection

specialists that if the goal of increasing the

yield and quality is to be achieved,

communication of research technology must

extend beyond the farm gate to promote

increased awareness among policy makers

and the society at large.

To understand how best to control plant

diseases to improve food security in the

context of climate change, plant protection

professionals must work with societal change,

defining its key processes and influencers to

effect change. More specifically they have a

key role to play in improving food security.

Plant pathologists and other crop

protection professionals develop and deploy

strategies based on well-established principles

to manage plant diseases and many may also

be applicable under climate change when

projected changes, processes and interactions

are factored in. Therefore, research to improve

adaptive capacity of crops by increasing their

resilience to diseases may not involve a totally

new approach. The bulk of any new

investment to improve control of disease in

food crops, therefore, needs only to accelerate

progress of new and existing promising

strategies and approaches and not to ‘re-

invent the wheel’ under the guise of climate-

change research.

It is a matter of great pleasure that the

Centre of Advanced Faculty Training in Plant

Pathology is suitably organizing this advanced

training programme on. It is hoped that the

scientists participating in this course would

effectively utilize the knowledge earned not

only in doing research and teaching but also to

find out ways and means of transferring the

technology to the farmers who are the sole

judge of our R&D efforts.

I have thus pleasure in the declaring

the training course “CLIMATE CHANGE,

PRECESION AGRICULTURE AND

INNOVATIVE DISEASE CONTROL

STRATEGIES” open and I wish the training

course, discussions and deliberations a grand

success.

‘Jai Hind’

* * * * * * * * *

iii

(Climate Change, Precision Agriculture and Innovative Disease Control Strategies)

- 1 -

DEPARTMENT OF PLANT PATHOLOGY

Establishment of University – 1960

Department created and Accredited – 1961

M. Sc. (Ag) Programme – 1963

Ph. D. Programme – 1965

Ist course – Introductory Plant Pathology

Ist Instructor – Dr. Y. L. Nene

Ist HOD – Dr. Y. L. Nene

Courses:

06 UG courses

32 PG courses

Staff position:

09 Professor

02 Honorary Professor

01 Emeritus Scientist

05 Associate Professor

02 Assistant Professor

13 Technical staff

10 Supporting staff

The G.B. Pant University of Agriculture & Technology (earlier known as U.P. Agriculture

University) was established in 1960. Department of Plant pathology was created and accredited by ICAR

in 1961. The postgraduate degree programme leading to M.Sc. (Ag.) Plant Pathology and Ph.D. Plant

Pathology were started in 1963 and 1965, respectively.

Faculty of Plant Pathology is highly qualified and includes 09 professors, 02 Honorary Professor,

01 Emeritus Scientist, 05 Associate Professors and 02 Assistant Professor with 13 technical staff and 10

supporting staffs.

Sl. No. Name of Faculty members Designation Area of specialization

1 Dr. Serge Savary Honorary Professor Epidemiology

2 Dr. S.C. Saxena Honorary Professor Maize Pathology

3 Dr. J. Kumar Professor & Head Plant disease management on small farm, IPM, Biological control, Molecular characterization of Plant Pathogens

4 Dr. H.S. Tripathi Professor Pulse diseases & virology

5 Dr. R.P. Awasthi Professor Oilseed crop disease

6 Dr. K.S. Dubey Professor Soybean diseases


- 2 -

7 Dr. (Mrs.) K. Vishunavat Professor Seed Pathology

8 Dr. U.S. Singh (on E.O.L.) Professor IPM & Biocontrol

9 Dr. V.S. Pundhir Professor Epidemiology of crop disease

10 Dr. Pradeep Kumar Professor Maize Pathology

11 Dr. R. K. Sahu Professor Sugarcane diseases

12 Dr. Vishwanath Assoc. Professor Soybean Pathology

13 Dr. R.P. Singh Sr. Research Officer Vegetable & maize pathology

14 Dr. Yogendra Singh Sr. Research Officer Sorghum diseases

15 Dr. K.P.S. Kushwaha Sr. Research Officer Mushroom & pulse diseases

17 Dr. A.K. Tewari Sr. Research Officer Oilseed crops diseases

18 Dr. (Mrs.) Deepshikha Jr. Research Officer Wheat diseases

19 Dr. (Mrs.) N.W. Zaidi SMS Bio-control

TEACHING

The department of plant pathology has made immense contribution in the area of teaching,

research and extension. A well-knit UG and PG programme with updated and modern syllabi is

already in operation in the department. The department offers 6 courses for undergraduate

students. There are 20 postgraduate courses leading to M.Sc. (Ag.) and Ph.D. degrees in Plant

Pathology. Since the inception of the department 313 M.Sc. (Ag.) and 176 Ph.D. students have

been awarded degrees.

Under graduate courses:

Sl. No. Course N0. Course name Credit

1. APP-312 Introductory Plant Pathology 3(2-0-3)

2. APP-314 Crop Diseases & their Management 2(1-0-3)

3. APP-330 Diseases of Fruit and Vegetable Crops 2(1-0-3)

4 APP/APE-322 Integrated Pest & Disease Management 2(1-0-3)

5. APP-381 Mushroom Cultivation 1(0-0-1x2)

6. APP-382 Biological Control of Plant Pathgen 2(0-0-2x2)

Post graduate courses:

Sl. No. Course N0. Course name Credit

1. APP-507 Disease of Field and Medicinal Plants 3(2-0-1)

2. APP-508 Disease of Fruits, Plantation and Ornamental Crops

3(2-0-1)

3. APP-509 Disease of Vegetable and Spice Crops 3(2-0-1)

4 APP/ENT- 514 Insects Vector of Plant Viruses and other Pathogens

2(1-0-1)

5. APP-515 Biological Control of Plant Diseases 3(2-0-1)

6. APP-516 Integrated Disease Management 3(2-0-1)

7. APP-517 Mushroom Production Technology 3(2-0-1)

8. APP-519 Post Harvest Disease 3(2-0-1)


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9. APP/ENT-520 Plant Quarantine 2(2-0-0)

10. BBB-599* Mycology 3(2-0-1)

11. APP-600 Master’s Seminar 1(0-0-1)

12. APP-601 Special Problem 1

13. APP-602 Plant Virology 3(2-0-1)

14. APP-603 Plant Bacteriology 3(2-0-1)

15. APP-604 Principles of Plant Pathology 3(3-0-0)

16. APP-606 Principles of Plant Disease Management 3(2-0-1)

17. APP-607 Plant Biosecurity and Biosafety 2(2-0-0)

18. APP-611 Chemicals in Plant Disease Management 3(2-0-1)

19. BBB-615* Advanced Mycology 3(2-0-1)

20. APP-616 Advanced Plant Virology 3(2-0-1)

21. APP-617 Advanced Bacteriology 3(2-0-1)

22. APP-618 Principles and Procedures of Certification 1(1-0-0)

23. APP-622 Techniques in Phytonematology 1(0-0-1)

24. APP-624 Cultural & Chemical Control of Plant Parasitic Nematodes

2(1-0-1)

25. APP-630 Phytonematology 2(1-0-1)

26. APP-690 Master Thesis Research 20

27. APP-704 Molecular Basis of Host Pathogen Interaction 3(2-0-1)

28. APP-710 Seed Health Technology 3(2-0-1)

29. APP-712 Ecology of Soilborne Plant Pathogen 3(2-0-1)

30. APP-713 Disease Resistance in Plants 2(2-0-0)

31. APP-718 Epidemiology and Forecasting of Plant Diseases

3(2-0-1)

32. APP-788 Doctoral Seminar I 1(0-0-1)

33. APP-789 Doctoral Seminar II 1(0-0-1)

34. APP-790 Ph.D. Thesis Research 45

*Course offered by Department of Biological Science, CBSH

Books Published

The department has unique distinction of producing 33 books published by not only Indian

but also reputed international publishers like Elsevier Science (UK), Gordon and Beach (UK),

Prentice Hall (USA), CRC Press (USA), Science Publisher (USA), Lewis Publishers (USA) etc. It

has also produced 13 technical bulletins. A number of text books in Hindi for U.G. students have

been published. The faculty members have written/prepared several laboratory manuals,

reference books, working sheets on diseases, bulletins, extension pamphlets, etc. for the benefit of

U.G. and P.G. students of plant pathology as well as for the farmers.

(A) Hindi – (15) (B) English– (41)

Plant Disease 8th Edition by R.S. Singh

An Introduction to Principles of Plant Pathology 4th Edition by R.S. Singh

Plant Pathogens: The Fungi by R.S. Singh

Plant Pathogens: The Viruses & Viroids by R.S. Singh

Plant Pathogens: The Prokaryotes by R.S. Singh

Integrated Disease Management by R.S. Singh

Diseases of Fruit Crops by R.S. Singh

Fungicides in Plant Disease Control by P.N. Thapliyal and Y.L. Nene


- 4 -

Diseases of Annual Edible Oilseed Crops Vol.-I by S.J. Kolte

Diseases of Annual Edible Oilseed Crops Vol.-II by S.J. Kolte

Diseases of Annual Edible Oilseed Crops Vol.-III by S.J. Kolte

Diseases of Linseed & Fibre Flex by S.J. Kolte

Castor Diseases & Crop Improvement by S.J. Kolte

Plant Diseases of International Importance Vol.I: Diseases of Cereals & Pulses by

U.S. Singh, A. N. Mukhopadhyay, J. Kumar, and H.S. Chaube

Plant Diseases of International Importance Vol.II: Diseases of Vegetables & Oil Seed

Crops by H.S. Chaube, U.S. Singh, A. N. Mukhopadhyay & J. Kumar

Plant Diseases of International Importance Vol.III: Diseases of Fruit Crops by Drs. J.

Kumar, H.S. Chaube, U. S. Singh & A. N. Mukhopadhyay

Plant Diseases of International Importance Vol.IV: Diseases of Sugar, Forest &

Plantation Crops A. N. Mukhopadhyay, J. Kumar, H.S. Chaube & U.S. Singh

Pathogenesis & Host Specificity in Plant Diseases Vol.I: Prokaryotes by U. S. Singh,

Keisuke Kohmoto and R. P. Singh

Pathogenesis & Host Specificity in Plant Diseases Vol. II: Eukaryotes by Keisuke

Kohmoto, U.S. Singh and R. P. Singh

Pathogenesis & Host Specificity in Plant Diseases Vol. III: Viruses & Viroids by R. P.

Singh, U.S. Singh and Keisuke Kohmoto.

Aromatic Rices by R.K. Singh, U.S. Singh and G. S. Khush

A Treatise on the Scented Rices of India by R.K. Singh and U.S. Singh

Scented Rices of Uttar Pradesh & Uttaranchal by R. K. Singh and U.S. Singh

Plant Disease Management : Principles & practices by H.S. Chaube and U.S. Singh

Molecular Methods in Plant Pathology by R. P. Singh and U.S. Singh

Soil Fungicides Vol.-I by A.P. Sinha and Kishan Singh

Soil Fungicides Vol.-II by A.P. Sinha and Kishan Singh

Experimental & Conceptual Plant Pathology Vol.I: Techniques by R.S. Singh, U. S.

Singh, W.M. Hess & D.J. Weber

Experimental & Conceptual Plant Pathology Vol. II: Pathogenesis and Host

Specificity by R.S. Singh, U. S. Singh, W.M. Hess & D.J. Weber

Experimental & Conceptual Plant Pathology Vol.III: Defense by R.S. Singh, U. S.

Singh, W.M. Hess & D.J. Weber

Seed Pathology, 2 volumes by V.K. Agarwal

Phytopathological Techniques by K. Vishunavat and S.J. Kolte

Crop Diseases & Their Management by H.S. Chaube & V.S. Pundhir

Seed borne diseases of crops & their management by V.K. Agrawal & Y.L. Nene

Plant Pathogens: the Nematodes by R.S. Singh

Disease of vegetables crops by R.S. Singh


- 5 -

Introductory Plant Pathology by H.S. Chaube & Ram Ji Singh

Seed Health Testing: Principles and Protocols by Karuna Vishunavat

Fundamentals of Seed Pathology by Karuna Vishunavat

Mushroom Production Technology by R.P. Singh & H.S. Chaube

The Elements of Plant Virology: Basic concepts and practical class exercises by S.J.

Kolte & A.K. Tewari

Books in Hindi:

lfCt;ksa ds jksx& th0 ,l0 nwcs] vesfjdk flag ¼1976½

Qlyksa ds jksx &,0,u0 eq[kksik/;k;] vkj0 ,0 flag ¼1976½

Qyksa ds jksx& ih0 ,u0 Fkify;ky] ,l0 ih0 ,l0 csuhoky ¼1976½

ikS/kksa ds jksx &vkj0 ,l0 flag ¼1976½

doduk'kh ,oa ikni jksx fu;a=.k& okbZ0 ,y0 uSu (1976)

Qlyksa ds jksxksa dh jksdFkke& laxeyky ¼1984½

e'k:e mRiknu rduhdh& vkj0 ih0 flag] v”kksd pkS/kjh] iznhi dqekj ¼1997½

feysV ds jksx&,0 ih0 flUgk ,oa ts0 ih0 mik/;k; (1997)

lfCt;ksa ds jksx& ,l0 ,u0 fo”odek Z] ,p0 ,l0 pkSos ,oa ,0ih0 flUgk (2003)

Qyksa ds jksx & ,l0 ,u0 fo”odekZ ¼2006½

lfCt;ksa ds jksxksa dh jksdFkke & ,l0 ,u0 fo'odekZ ¼2000½

cht jksx foKku& oh0 ds0 vxzoky ¼1999½

eDdk ds jksx& laxe yky ¼1993½

/kku ds jksx & vkj0 ,0 flag ,oa ts0 lh0 HkV~V ¼1995½

Qly&lCth&Qy jksx] igpku ,oa izcU/k & ;ksxsUnz flag ,oa vf[kys'k flag

Manuals: Chemicals in Plant Disease Control by Y.L. Nene, R.K. Tripathi, P.N. Thapliyal & S.C.

Saxena (1974)

Management of Soil Borne Plant Diseases by R.S. Singh (1980)

Biocontrol of Fungal Plant Disease by A.N. Mukhopadhyay, H.S. Chaube, U.S. Singh & S.C. Saxena (1994)

Identification of Plant Diseases and their Control by A. N. Tewari (2000)

Epidemiology in Plant Diseases by V.S. Pundhir (2000)

Disease resistance in plants by V.S. Pundhir (2001)


- 6 -

Seed Pathology: A Practical Manual by K. Vishunavat (2002)

Laboratory Methods in Plant Pathology by Pradeep Kumar, Y.P.S. Rathi, & H.S. Tripathi (2002)

Phytovirology: Laboratory Manual by Y.P.S. Rathi, H.S. Tripathi & Pradeep Kumar (2002)

Diagnosis of Plant Diseases by A.N. Tewari (2002)

Identification of Plant Disease by A.N. Tewari (2003)

Introductory Plant Pathology (UG) by Y.P.S. Rathi, P. Kumar, & H.S. Tripathi (2003)

Diagnosis of Plant Diseases: Laboratory Manual by A.N. Tewari (2004)

Mushroom Cultivation: Laboratory Manual by R.P. Singh (2004)

Crop Diseases and their Management by H.S. Chaube, V.S. Pundhir & S.N. Vishwakarma (2004)

Laboratory Manual of Forest Pathology by K. P.Singh, J. Kumar and P. Srinivas (2007)

Integrated Pest Management by Ruchira Tiwari, S.C.Saxena and Akhilesh Singh (2008)

RESEARCH

Research work in the department began since the inception of the University. With the

addition of new programme and staff strength, the research activities got diversified

encompassing, Ecology of soil borne plant pathogens, Epidemiology and Forecasting, Biological

control and IPM, Molecular Biology and Population Biology, Seed Pathology, Fungicides,

Nematology, Phytovirology, Phytobacteriology and Biology & Technology of Mushroom

Production. The department has several research projects funded by national and international

funding agencies. The department is guiding the research work at the regional station such as

Bharsar, Kashipur, Lohaghat, Majhera and Ranichauri on pathological aspects. The scientists of

the department have won many national and international awards.

The department is actively engaged in the research work on both fundamental and applied

aspects in frontier areas of plant pathology. The plant protection technology developed by the

department is being effectively communicated to the farming community of state of Uttaranchal.

The department has to cater the needs of not only farmers of the plain but also of hills located at

different altitudes. In hills crops, diseases and cropping practices vary a lot depending on altitudes

and they are quite different from plain. This offers a big challenge to the Centre of Advanced

Studies in Plant Pathology.

Significant Contribution

Cause and control of Khaira disease of rice

Development of selective media for isolation and enumeration of Pythium and Fusarium


- 7 -

Mechanism of biological control in soil amended with organic matters

Biology and characterization of legume viruses

Ecology of soil – borne pathogens (Fusarium, Pythium, Rhizoctonia solani, Sclerotium rofsii)

Mechanism of absorption, translocation and distribution of fungicides in plants

Methods for quantitative estimation of fungicides like metalaxyl, organotin compounds, carbendazim

etc.

Hormonal action of fungicides

Phenolics in Plant disease resistance

Biological control with introduced antagonists

Etiology & management of mango malformation

Etiology and management of shisham wilt.

Epidemiology and Genetics of Karnal bunt fungus

Population biology of rice blast fungus, Magnaporthe grisea

Mechanism of intra-field variability in Rhizoctonia solani

Soil solarization

Mushrooms – Development of strains, and production technologies

Role of Ps. fluorescens in sporophores development of A. bisporus

Compost formulation with Sugarcane baggase + Wheat Straw, 2:1 developed to reduce cost of

cultivation of Agaricus bisporus.

Developed chemical treatment (Formalin 15ml + Bavistin 0.5g/10kg compost) of long method

compost to avoid the moulds in cultivation of A. bisporus.

Recommended supplementation of substrate with 2% mixture of Neem cake + Wheat straw + Rice

bran + Soybean meal for Pleurotus spp. cultivation.

Standardized cultivation of Auricularia polytricha using sterilized wheat straw supplemented with

wheat bran (5%).

Standardized cultivation of Lentinula edodes with substrate

popular sawdust.

Systemic induced resistance in brassicae.

Use of siderophore producing Pseudomonads for early fruiting

and enhanced yield of Agaricus bisporus.

Use of Pseudomonas fluorescens for control of mushroom

diseases caused by Verticillium, Sepedonium, Trichoderma and Fusarium.

Pleurotus sajor-caju and P. florida recommended for commercial cultivation using soybean straw /

Paddy straw / Wheat straw / Mustard straw.

Standardized cultivation technology for Hypsizygus almarius

using wheat straw supplemented with wheat bran.

Standardized cultivation of Calocybe indica using wheat

straw as a substrate with casing of FYM + Spent Compost +

Lentinula edodes


- 8 -

Sand (2:1:1).

A relay cropping schedule developed for Tarai region of Uttaranchal: two

crops Agaricus bisporus (Sept. - March), four crops Pleurotus spp. (Sept.-

Nov. and Feb.,- April) and three crops of Calocybe indica (March-October).

Developed two strains of Agaricus bisporus, Pant 31 and Pant 52, now included in multilocational

testing under coordinated trials.

Development and commercialization of seven hybrids of oyster mushroom.

Associated with multilocational testing and release of the strains NCS-100, NCS-102, NCH-102 of

A. bisporus.

120 mushroom species from different locations in Uttaranchal

have been collected and preserved in the museum of the

centre.

Of the collected mushrooms five Auricularia, four species of

Pleurotus and two species of Ganoderma have been brought

under cultivation.

Developed / standardized technology for production of traditional

value added mushroom products viz. ‘Sev’, ‘Warian’, ‘Papad’ and ‘Mathri’.

Isolated a high value cater pillar mushroom

Cordyceps sinensis from high altitudes of

Uttaranchal and analysed for antioxidative

properties.

MAJOR ACHIEVEMENTS

Twenty seven wheat lines, combining better agronomic characteristics and resistance to diseases

including Karnal bunt have been identified (Shanghi-4, BW 1052, HUW 318, Lira/Hyan’S’ VUI’S’,

CUMPAS 88, BOBWHITE, SPRW 15/BB/Sn

64/KLRE/3/CHA/4/GB(K)/16/VEE/ GOV/AZ/MU, NI9947, Raj 3666,

UP 1170, HS 265, HD 2590, HS317, PH 130, PH 131, PH 147, PH

148, PH 168, HW 2004, GW 188, MACS 2496, CPAN 3004, K8804,

K8806, ISWYN-29 (Veery”S”) and Annapurna).

Foliar blight of wheat has now been assumed as a problem in Tarai

areas of U.P and foothills of Uttaranchal. Bipolaris sorokiniana -

Dreschlera sorokiniana, was found associated with the disease in

this area. Karnal bunt of wheat caused by Tilletia indica Mitra, is widely distributed in various

Western and Eastern districts of U.P while the North hills and Southern dry areas are free from the

disease.

Multiple disease control in wheat has been obtained by seed treatment with Raxil 2DS @

1.5g/Kg seed + one foliar spray fungicide Folicur 250 EW (Tebuconazole) @ 500ml/ha, which

Ganoderma lucidum

Cordyceps sinensis

Calocybe indica


- 9 -

controls loose smut, brown rust, yellow rust, powdery mildew and leaf blight disease very

effectively.

The mixture of HD 2329 + WH 542 + UP 2338 produced highest yield recording 11.67 per cent

higher as compared to average yield of their components.

Among new fungicides Raxil 2DS (Tebuconazole) @ 1.0, 1.5, 2.0 and 2.5g/kg seed, Flutriafol

and Dividend @ 2.5g/Kg seed were found highly effective in controlling the disease. Raxil 2DS

@ 1.5g/Kg seed as slurry treatment gave complete control of loose smut.

New techniques for embryo count and seedling count for loose smut, modified partial vacuum

inoculation method of loose smut, creation of artificial epiphytotics of Karnal bunt, NaOH seed

soaked method for Karnal bunt detection and detached leaf technique for screening against

leaf blight using pathogen toxin developed.

The major emphasis has been on the screening of maize germplasms to various diseases with

special reference to brown stripe downy mildew, banded leaf and sheath blight and Erwinia

stalk rot. A sick-plot has been developed to ensure natural source of inoculum. Efficient

techniques for mass multiplication of inoculum and screening of germplasms have been

developed to create epiphytotic conditions. The selected genotypes have been utilized for

evolving agronomically adaptable varieties. Several promising hybrids and composites have

developed and released following interdisciplinary approach.

Studies on estimation of yield losses, epidemiological parameters on various economically

important diseases of maize have been worked out to evolve suitable control measures and

have been recommended to farmers in the region.

Based on the survey and surveillance studies the information on the occurrence of various

diseases in UP and Uttaranchal, a disease map has been prepared and monitored to finalize the

out breaks of one or more diseases in a given area based on weather parameters. It will help the

growers to be prepared to save the crop from recommended plant protection measures.

An repository of >600 isolates of biocontrol agents developed at Pantnagar & Ranichauri.

These isolates are suited for different crops & agro-ecological conditions.

Standard methods developed for testing hyphal and sclerotial colonization.

Isolate of T. virens capable of colonizing sclerotia of Rhizoctonia, Sclerotium and Sclerotinia

isolated for the first time. It may have great potential.

16 new technologies related with mass multiplication and formulation of microbial bio-agents

developed and are in the process of being patented.

Several genotypes including SPV 462, SPV 475, SPV 1685, SPH 1375, SPH 1420, CSV 13,

CSV 15, CSH 14, CSH 16, CSH 18, G-01-03, G-09-03, GMRP 91, RS 629, UTFS 45, UTMC

523 and AKR 150 have been identified with high level of resistance to anthracnose and zonate

leaf spot diseases.

Biocontrol agents T. harzianum and P. fluorescens have been found effective in increasing the

growth of plants and reducing the severity of zonate leaf spot. G. virens and T. viride have


- 10 -

been found most effective against anthracnose pathogen.

The cause of Khaira as zinc deficiency was established for the first time and zinc sulphate

+slacked lime application schedule was developed for the control of the disease

Inoculation technique was developed to create “Kresek” phase in rice seedlings. Pre-planting root

exposure technique in a suspension of 108cells/ml for 24 hrs gave the maximum “Kresek”. Root

inoculation, in general was found better for development of wilt symptoms than shoot inoculation.

A simple technique has been developed to detect the pathogen in and/or on seeds. The

presence of viable pathogen has been demonstrated from infected seeds stored at room

temperature up to 11 months after harvest.

The disease is sporadic in occurrence often becomes serious in nature. Chemical control trials

showed that the disease can effectively be controlled by giving 2-3 foliar sprays of

streptocycline @ 15 g/ha.

A number of new fungicides along with recommended ones and botanicals were tested against

sheath blight. Foliar sprays with Anvil, Contaf, Opus, Swing and RIL F004 @ 2 ml/l and Tilt @

1 ml/l were found highly effective in controlling sheath blight. Foliar sprays with Neem gold @

20 ml /lit. or Neem azal @ 3ml/lit. was found significantly effective in reducing sheath blight

and increasing grain yield.

Foliar sprays with talc based formulations of the bioagents (Trichoderma harzianum, or

Pseudomonas fluorescence, rice leaf isolates) were found effective in reducing sheath blight

and increasing grain yield. Foliar sprays with the bioagents (T.harzianum) or P. fluorescence)

given 7 days before inoculation with R. solani was highly effective against the disease.

Seed or soil treatment with T. harzianum or P. fluorescence @ 2, 4 or 8 g/kg enhanced root

and shoot growth and fresh and dry weight of rice seedlings.

Seed treatment with fungorene followed by one spray of carbendazim (@ 0.05% at tillering at

diseases appearance) and two sprays of Hinosan @ 0.1% at panicle initiation and 50%

flowering was most effective and economical treatment in reducing the disease intensity and

increasing the yield.

For the first time, true sclerotia were observed in Kumaon and Garhwal regions at an altitude of

900 m above. True sclerotia have a dormancy period of approximately six months. Exposure of

sclerotia to near ultraviolet radiation for an hour breaks the dormancy

and increased germination.

Trichoderma may reduce population of earthworm in vermicomposting

during early days

An repository of >600 isolates of biocontrol agents developed at

Pantnagar & Ranichauri. These isolates are suited for different crops & agro-ecological

conditions.

Isolates of T. virens capable of colonizing sclerotia of Rhizoctonia, Sclerotium and Sclerotinia

isolated for the first time. It may have great potential.


- 11 -

Standard methods developed for testing hyphal and sclerotial colonization.

16 new technologies related with mass multiplication and formulation of microbial bioagents

developed and are in the process of being patented.

Effect of different physical factors and extracts on the germination of true sclerotia was studied.

Maximum germination was observed at 250 C and at pH 6.0, in fluorescent light. Among the

substratum, maximum germination occurred on moist sand. Soil extract was more favourable

than other extracts. The number of stipes and mature head formation was directly correlated

with the size and weight of the sclerotia.

The viability of the 3 propagules namely; conidia, pseudo and true sclerotia stored under

different conditions showed that conidia remain viable from 2-3 months, pseudo- sclerotia from

4-6 months and true sclerotia up to 11 months at room temperature and under field conditions.

True sclerotia buried at different depth (2.5 to 10 cm) in soil germinated well, but scleroita

buried at 15 cm depth did not germinate and rotted.

Discoloured grains of various types were grouped according to their symptoms. The fungi

responsible for each type of symptoms were identified. Ash grey discolouration of glumes

separated by dark brown band was caused by Alternaria alternata and Nigrospora oryzae.

Spots with dark brown margin and ash grey centre by Curvularia lunata and Alternaria

alternata, light yellow to light brown spots by C. pallescens, Fusarium equiseti and N. oryzae,

Brown to black dot by Phyllosticta oryzae Dark brown to black spot and specks by Drechslera

victoriae, D. rostratum and D. oryzae, light to dark brown glumes by Sarocladium oryzae and

D. oryzae, and light to dark brown spots by D. Australiense.

Rice varieties Manhar, Narendra 80, Saket 7, Ajaya, Bansmati, 385 showed higher incidence

(34.1 to 41.8%) whereas Sarju 52, UPR 1561-6-3, Pusa 44, Jaya, Pant Dhan 10 and improved

Sharbati exhibited lower (18.4-22.3%) incidence of seed discolouration. Bipolaris oyzae

caused highest seed discolouration which is followed by Fusarium moniliforme, curvularia

lunata and Fusarium graminium in all the test varieties.

On the basis of the symptoms pattern and transmissibility of the pathogen through grafting and

eriophyied mite (Aceria cajani), presence of foreign ribonucleic protein and nuclear inclusion

like bodies in the phloem cell indicated the viral (RNA virus) nature of the pathogen of sterility

mosaic of pigeon pea. The vector mite of the pathogen was found on lower surface of leaves

of Canavis sativus and Oxalis circulata weeds in this area. Mild mosaic, ring spot and severe

mosaic symptoms were observed in different as well as same cultivar. This observation reveals

the presence of variation in the pathogen.

Germplasm lines/ cultivars screened viz; ICP 14290, ICP 92059,ICP 8093, KPBR 80-2-2, PL

366, ICPL 371, Bahar, NP (WR) 15.were found resistan against Phytophthora stem blight.

Some resistant donors for mungbean yellow mosaic virus have been identified i.e. UPU-

1,UPU-2,UPU-3, UG-370, PDU-104, NDU-88-8, UG-737, and UG-774. The varieties thus

evolved include PU-19, PU- 30, and PU-35., Manikya, resistant lines/cultivars identified: ML-


- 12 -

62, ML-65, Pant M-4, Pant M-5, ML-131, NDM 88-14, ML-682, PDM-27, ML- 15, ML-803, ML-

682 and 11/ 395 and for Urdbean leaf crinkle virus, SHU 9504, -9513,-9515, -9516, -9520, -

9522, -9528, KU 96-1, UG 737 and TPU-4.

Seed treatment with carbendazim (0.1%) followed by two prophylactic sprays of carbendazim

(0, 05%) or Dithane M-45 @ 0.25% was found most effective in reducing disease severity of

anthracnose disease. In early sown crop high disease severity was observed while in late

sown crop low disease severity was recorded. Inter cropping with cereals or pulses have no

effect on anthracnose severity.

Propiconazol 0.1%, carbendazim 0.1%, hexaconazol 0.1%, mancozeb 0.25% sprayed plots

have low disease severity and high grain yield against Cercospora leaf spot.

Studies on integrated management of wilt/root rot/collar rot showed that Seed treatment with

fungicide alone or in combination with other fungicides/ bio agents were found effective.

Among the fungicides seed treatment with Bavistin + Thiram (1:2), vitavax + Thiram (1:2),

vitavax, Bavistin, Bayleton, Bio agent Gliocladium virens + Vitavax and Pseudomonas

fluorescence) decreased the seedling mortality, improved germ inability, plant stand and yield.

Eleven thousand germplasm lines/ breeding populations F2,

F3, F4 and F5 generations were screened. Many germplasm/

accessions were found resistant/ tolerant to Botrytis gray

mould viz; ICC 1069, ICC 10302, ICCL 87322, ICC 1599, -

15980, - 8529, ICCV 88510, E100Y (M) BG 256, BG261,

H86-73, IGCP 6 and GNG 146.

Lentil entries evaluated under sick plot for wilt/root rot/ collar

rot diseases. The following lines were found promising viz;

LL 383, PL 81-17, LH 54-8, DPL-58, DPL 14, Jawahar Massor- 3, DPL 112, IPL-114, L 4147

and Pant L 639.

The promising germplasm lines/ cultivars are as follows: DPL 62, PL-406, L 4076, TL 717, E

153, IPL 101, IPL 105, PL- 639, LH 84-8, and Precoz .

The field pea lines were found promising JP 141, Pant P-5, KFPD 24 (swati), HUDP 15, KFPD-

2, HFP-4, P1361, EC-1, P-632, P 108-1, KPMR 444, KF 9412, DPR 48, T-10, KPMRD348,

DDR13, IM9102, KFP 141 and KPMR 467 against powdery mildew and JP 141, Pant P-5, P

10, FP 141, KDMRD 384, HUDP-9, HUP-2 and T-10 were found promising against rust

disease.

Mid-September planting or early October planting of rapeseed-mustard has been found to

escape from Alternaria blight (Alternaria brassicae) downy mildew (Peronospora parasitica)

and white rust (Albugo candida) diseases as against mid and late October planting. In general

high occurrence of the floral infection (staghead phase) of white rust and downy mildew during

flowering period has been found to be associated with reduced period, i.e. 2-6 hours, of bright

sunshine/day concomitant with the mean maximum temperature of 21-250C, the mean


- 13 -

minimum temperature of 6-100C and higher total rainfall up to 166 mm. Bright sunshine hours

/day has a significant negative correlation whereas total rainfall has a significant positive

correlation with staghead development.

All the three important foliar diseases of rapeseed-mustard could be effectively controlled by

following integrated package of balanced N100 P40K40 application, early October sowing and

treating the seed with Apron 35 SD @ 6g kg-1 seed followed by spray of mixture of metalaxyl +

mancozeb (i.e Ridomil MZ 72 WP @ 0.25%) at flowering stage and by spray of mancozeb or

iprodione @ 0.2% at pod formation stage. In situations where Sclerotinia stem rot and / or

powdery mildew appeared to be important in a particular crop season, a spray of mixture of

carbendazim (0.05%) + mancozeb (0.2%) was found to give excellent cost effective control of

the diseases with significant increase in seed yield of the crop.

Among the botanicals, leaf extracts of Eucalyptus globosus (5%) and Azadirchta indica (5%)

have been proved to exhibit greater antifungal activity against A. brassicae and Albugo

candida and showed significant reduction in the severity of Alternaria blight and white rust

diseases which was rated to be at par with mancozeb fungicide spray.

Some abiotic chemical nutrient salts such as calcium sulphate (1%), zinc sulphate(0.1%) and

borax (0.5%) and biocontrol agents such as Trichoderma harzianum and non-aggressive D

pathotype of A.brassicae have been shown to induce systemic host resistance in mustard

against aggressive “A” pathotype of A. brassicae and virulent race(s) of A. candida.

The staghead phase in B. juncea has been investigated to be due to A. candida and not due P.

parasitica. Tissues at the staghead phase become more susceptible to P. parasitica than

normal tissues of the same plant.

B. juncea genotypes (EC 399296, EC 399299, EC 399301, EC 399313, PAB-9535, Divya

Selection-2 and PAB 9511), B. napus genotypes (EC 338997, BNS-4) and B. carinata (PBC-

9221) have been shown to possess resistance to white rust coupled with high degree of

tolerance to Alternaria blight. Reduced sporulation is identified to be the major component for

slow blighting.

B. juncea (RESJ 836), B. rapa (RESR 219) and B. napus (EC 339000) have been selected for

resistance to downy mildew and for high yield performance. Total 52 genotypes of mustard

representing at least 12 differential resistance sources, 23 lines of yellow sarson representing

6 differential resistance sources and 54 lines of B. napus representing 3 differential resistance

sources to downy mildew have been identified.

A new short duration (95-100 days) short statured (85- 96 cm) plant type of mustard strain

‘DIVYA’ possessing high degree of tolerance to Alternaria blight suitable for intercropping with

autumn sown sugarcane and potato yielding with an average of 15-22 q ha-1 has been

developed. This ‘Mustard DIVYA’ plant type is now recommended as a source for breeding

more and more improved varieties of mustard as it has been proved to have good general

combining ability for short stature characteristics.


- 14 -

Seed treatment with mancozeb @ 0.2% + thiram @ 0.2% has been found to control seed,

seedling and root rot diseases of groundnut. However seed treatment with thiram @ 0.2% +

vitavax @ 0.2% has been found to control collar rot (Sclerotium rolfsii) of groundnut. Two

sprays of carbendazim @ 0.05% have been found to give excellent control of early and late

leaf spot (tikka disease) of groundnut.

Mid September planting of sunflower was found to escape the occurrence of major diseases

like Sclerotinia wilt and rot, Sclerotium wilt, charcoal rot and toxemia. Severity of Alternaria

blight was found to be negligible and did not cause any reduction in yield. The crop could be

harvested by 15th December. The yield obtained was 16 q/ha.

The average percent loss has been noted in the range of 50.6 to 80.7 percent due to Alternaria

blight disease under Kharif conditions. However, the percent loss in oil has been shown in the

range of 21.6 to 32.3. To control the disease, total 4 sprays of mancozeb @ 0.3% at 10 day

interval have been found effective.

A repository of about 5000 rice blast isolates was made from 30 locations in Indian Himalayas at

Hill Campus, Ranichauri. Blast pathogen population from the region was analyzed using molecular

markers and phenotypic assays. Most locations sampled and analyzed had distinct populations

with some containing one or a few lineages and others were very diverse. Within an

agroecological region migration appeared to be high. The structure of some populations could be

affected to some extent by sexual recombination.

Magnaporthe grisea isolates derived from Eleusine coracana, Setaria italica and Echinochloa

frumentaceum collected from a disease screening nursery were cross compatible. The

chromosome number of each isolate was found to be six or seven. Similarity of karyotypes was

found among isolates with in a lineage though between lineages some variability was noticed. A

remarkable similarity between karyotypes of Eleusine coracana and Setaria italica was observed. All

of these isolates were fertile and mated with each other to produce productive perithecia. The

existing data however showed no evidence of genetic exchange among host-limited M. grisea

populations in Indian Himalayas.

No strong relationship appeared between the number of virulences in a pathotyope and its frequency

of detection. The frequency of virulent phenotype to a cultivar and susceptibility of that cultivar in the

field did not correspond. The number of virulences per isolate was in general less than the number

of virulences per pathotype, which indicated predominance of isolates from pathotypes with fewer

virulences. There was a tendency for the pathotypes to have fewer virulences. The frequency of

virulence among rare pathotypes was higher than common pathotypes against all the differential

NILs, including two-gene pyramids. These rare pathotypes could be the potential source of

resistance breakdown of the novel resistance genes.

Blast resistant gene Pi-2(t) appeared to have the broadest and Pi-1(t) the narrowest resistant

spectra. Compatibility to Pi-2 (t) gene did not appear to limit compatibilities with other resistant


- 15 -

genes. Loss of avirulence to all the five major gene tested may carry a serious fitness penalty.

Major gene Pi-2 and gene combination Pi-1,2 showed least compatibilities and hold promise

in managing blast in the region. In the overall Himalayan population, gene combinations in

general were effective at most locations. Combination of Pi-1+2 genes was effective at most

locations until the year tested. However, three gene pyramid [Pi-1(t) + Pi-2(t)+Pi-4(t)] resisted

infection at all locations.

It was inferred that the pathotype composition of the blast pathogen composition in the Indian

Himalayas was very complex and diversifying the resistance genes in various rice breeding

programmes should prove to be a useful strategy for disease management.

A common minimum programme under bio-intensive IPM in vegetables in Uttaranchal hills was

designed that is extended to over 2000 farmers from 20 villages in district Tehri Garhwal.

Epidemiological considerations in the apple scab disease management led to the development

of disease prediction models. Relation of degree-day accumulations to maturation of

ascospores, and potential ascospore dose (PAD) were found to be useful for predicting the

total amount of inoculum in an orchard thereby effectively improving apple scab management.

Out of 71 genotypes tested against red rot caused by Colletotrichum falcatum, four genotypes

viz; Co Pant 92226, Co Pant 96216, Co Pant 97222 and CoJ 83 were found resistant and

another 24 exhibited fairly good tolerance.

Seed treatment with Thiram + Carbendazim (2:1) @ 3g/kg seed or Vitavax 0.2% controlled the

seed and seedling rots and improved the seedling emergence without any adverse effect on

the nodulation and invariably yield were increased. Seed treatment with Trichoderma

harizianum, T. viride or Pseudomonas fluorescens @ 10g/kg controlled seed and seedling rots

and increased plant emergence.

Purple seed stain disease can be effectively controlled by seed treatment with thiram +

carbendazim (2:1) @ 3 g/kg seed followed by two sprays of benomyl or Carbendazim @ 0.5

kg/ha.

Rhizoctonia aerial blight can be effectively controlled by two sprays of carbendazim @ 0.5

kg/ha. Seed treatment with T. harzianum or Pseudomonas fluorescens 10g/kg seed + soil

treatment with pant Bioagent-3 mixed with FYM @50q/ha followed by two sprays of T.

harzianum @ 0.25% reduced the disease severity of RAB.

Pod blight and foliar diseases caused by Colletrotichum dematium var truncatum could be

effectively controlled by the use of carbednazim 0.05%, Mancozeb 0.25%, Copperoxychloride

0.3%, Thiophanate methyl 0.05%, Chlorothalonil 0.25%, Hexaconazole 0.1% and

Propiconazole 0.1%. First spray should be given as soon as disease appear and second spray

after 15 days of first spray.


- 16 -

Rust disease could be effectively controlled with three sprays of Benomyl 0.05%, Mancozeb

0.25% or Zineb 0.25%, at 50, 60 and 70 days after sowing. Varieties Ankur, PK-7139, PK-

7394, PK-7121, PK-7391 were resistant.

Charcoal rot disease can be effectively controlled by seed treatment with Trichoderma

harzianum @ 0.2% + vitavax @ 0.1%.

Pre-mature drying problem Soybean can be minimized by seed treatment with carbendazim +

Thiram (2:1) @ 3g/kg seed followed by two sprays with carbendazim, mancozeb and

Aureofungin. Varieties PSS-1, PS-1042, PK-1162, PK-1242 and PK-1250 were found to be

superior for premature drying problem.

Integrated disease management (IDM) modules based on combined use of cultural practices,

fungicides for fungal disease, insecticide for virus disease and host resistance were evaluated

against RAB and Soybean yellow Mosaic virus diseases.

Bacterial pustules can be successfully controlled by two sprays at 45 and 55 days after

planting with a mixture of Blitox-50 (1.5 kg/ha) + Agrimycin-100 (150g/ha) or streptocycline

(150 g/ha) + copper sulphate (1kg/ha).

Soybean yellow Mosaic can be very effectively controlled by four sprays with oxymethyl

demoton @ 1l/1000 lit/ha at 20, 30, 40 and 50 days after planting. Soil application with Phorate

10G @ 10 kg/ha and Furadan 3G @ 17.5 kg/ha controlled the disease. Varieties PK-1284,

1251, 1259, 1043, 1225, 1303, 1314, 1343, 1347, PS-1042 PS-564, 1364 were identified as

resistant to Soybean yellow Mosaic virus.

EXTENSION The scientists also participate in the farmers contact programme as well as practical

trainings at different levels including those of IAS and PCS officers, Extension workers, Agricultural

officers, Farmers, Defense Personnels etc. The Scientists of the department also actively

participate in the trainings organized under the T&V programme for the benefit of farmers/State

level Agricultural Officers. Two Professors (Extension Pathology) and crop disease specialists are

deputed to “Help Line Service” started recently by the University under Agriculture Technology

Information Centre (ATIC). The telephone number of help line services is 05944-234810 and 1551.

Technology developed by the centre is regularly communicated to the farmers of the 13 districts of

Uttaranchal State through the extension staff (Plant Protection) of both university and state

agriculture and horticulture departments posted in all districts of the state. The radio talks and TV

programme are delivered. Popular articles and disease circulars are published regularly for the

benefit of the farmers.

UP-GRADATION TO CENTRE OF ADVANCED STUDIES

In view of the outstanding quality of teaching, research and extension work being carried out by


- 17 -

the department, ICAR vide letter No. 1-2/93 (CAS)UNDP dated Feb.02, 1995 upgraded the department

to the status of the centre of advanced studies in plant pathology. Major mandate of the CAS was to train

scientific faculty from all over the country in important and innovative areas of plant pathology. So far

under CAS, 16 trainings have been conducted and 336 scientists from all over the country have been

trained in different areas. Centre of Advanced Studies in Plant Pathology at Pantnagar was awarded a

certificate of Appreciation in commemoration of Golden Jubilee year of independence (1998) for

organizing the programmes for human resource development and developing excellent instructional

material by the education division, ICAR on August 14, 1998. The progress report CAS in Plant

Pathology during X plan is as follows:

Trainings Held

1. Recent advances in biology, epidemiology and management of diseases of major kharif

crops (Sept. 19- Oct. 12, 1996)

2. Recent advances in biology, epidemiology and management of diseases of major rabi crops

(Feb. 25 –March 17, 1997)

3. Ecology and ecofriendly management of soil-borne plant pathogens (Jan 12 – Feb. 02, 1998)

4. Advanced techniques in plant pathology (Oct. 12 – Nov. 02, 1998)

5. Recent advances in detection and management of seed-borne pathogens (March 10-30,

1999)

6. Recent advances etiology and management of root-rot and wilt complexes (Nov. 26 – Dec.

16, 1998)

7. Integrated pest management with particular reference to plant diseases: concept, potential

and application (Nov. 23 –Dec. 13, 2000)

8. Recent advances in research on major diseases of horticultural crops (March 01-30, 2001)

9. Recent advances in plant protection technology for sustainable agriculture (Nov. 19 –Dec.

09, 2001)

10. Plant diseases diagnosis: past, present and future (Feb. 13, - March 05, 2002)

11. Chemicals in plant protection: past, present and future (Jan. 28 – Feb. 17, 2003)


- 18 -

12. Eco-friendly management of plant diseases of national importance: present status and

research and extension needs (Nov. 10-30, 2003)

13. Ecologically sustainable management of plant diseases: status and strategies (March 22-

April 11, 2004)

14. Disease resistance in field and horticulture crops: key to sustainable agriculture (Dec. 10-30,

2004)

15. Regulatory and cultural practices in plant disease management (Dec. 03-21, 2005)

16. Crop disease management: needs and outlook for transgenics, microbial antagonists and

botanicals (March 21 – April 10, 2006)

17. Soil Health and Crop Disease Management (December 02-22, 2007)

18. Role of Mineral Nutrients and Innovative Eco-friendly Measures in Crop Disease

Management (March 22- April 11, 2007)

19. Plant Disease Management on Small Farms (January 03-23, 2008)

20. Seed Health Management for Better Productivity (March 28 to April 17, 2008)

21. Recent Advances in Plant Disease Management (Dec. 13, 08 to Jan. 02, 09)

22. Recent Advances in Biological Control of Plant Diseases (March 20 - April 09, 2009)

23. Plant Pathology in Practice (March 22 to April 11, 2010)

24. Climate change, precision agriculture and innovative disease control strategies (March 23 to

April 12, 2011)

Sl. No. State Total Sl. No. State Total

1. Andhra Pradesh 13 13. Maharashtra 37

2. Assam 13 14. Manipur 01

3. Bihar 21 15. Meghalaya 01

4. Chattishgarh 07 16. Nagaland 01

5. Gujarat 42 17. Orissa 13

6. Haryana 04 18. Punjab 05

7. Himanchal Pradesh 38 19. Rajasthan 42

8. Jammu & Kashmir 32 20. Sikkim 01

9. Jharkhand 05 21. Tamil Nadu 10

10. Karnataka 22 22. Uttar Pradesh 67

11. Kerla 05 23. Uttarakhand 75

12. Madhya Pradesh 25 24. West Bengal 18

Total = 498


- 19 -

INFRASTRUCTURE

Wheat Pathology Lab. – General Path, Epidemiology, Toxin, Tissue Culture

Maize Pathology Lab. – General Plant Pathology, Bacteriology

Rice Pathology Lab. – General Plant Pathology

Ecology and Vegetable Pathology Lab. – Ecology, Histopathology, Biocontrol, Nematodes

Soybean Path. Lab.– General Plant Pathology, Fungicides

Oil Seed Path. Lab.– General Pl. Path., Tissue, Culture, Histopathology, Toxins

Pulse Path. Lab. – General Pl. Path., Phytovirology

Seed Path. Lab. – General Path, Seed Borne diseases

Biocontrol Lab. – Biocontrol & IPM

Molecular Pl. Path Lab. – Population biology & host- pathogen interaction

Mushroom Research – Research & training

Glass houses – 3

Polyhouses – 3

UG Practical Lab – 1

PG Lab – 1

Training Hall – 1

Conference Hall – 1

Office – 1

Huts for Mushroom Production


- 20 -

Research Project (on going)

Large Scale Demonstration of IPM technology through KVKs in Network Mode (HTMM-I)

Promoting IPM through a Common Minimum Programme in Vegetable Cultivation in

Uttarakhand Hills (RKVY, Govt. of India)

Programme Mode Support in Agrobiotechnology (DBT)

Translational Research Centre on Biopesticides (DBT)

AICRP on Biological Control (ICAR)

All India Coordinated Wheat and Barley Improvement Project-Plant Pathology component

(ICAR)


- 21 -

AIC Chickpea Improvement Project (ICAR)

AIC Pigeonpea Improvement Project (ICAR)

AIC MullaRP Improvement Project (ICAR)

Screening of chickpea germplasms/lines against BGM disease-(NBPGR)

All India Coordinated Soybean Improvement Project (ICAR)

All India Coordinator Research Project on Rapeseed & Mustard (ICAR)

All India Coordinated Rice Improvement Project (ICAR)

Cereal Systems Initiative for South ASIA (CSISA) Objective 3 (IRRI)

AICRP on (NSP) Seed Technology Research (ICAR)

DUS Test Centre for Implementation of PVP-legislation for forage sorghum at Pantnagar

(ICAR)

Seed Production in agriculture crops and fisheries (Mega Seed Project) in Seed

Technology Research (ICAR)

All India Coordinator Potato Improvement Project (ICAR)

All India Coordinated Vegetable Improvement Project (ICAR)

All India coordinated Maize Improvement Project (ICAR)

All India Coordinated Sugarcane Improvement Project (ICAR)

All India Coordinated Sorghum Improvement Project (ICAR)

All India Coordinated Mushroom Improvement Project (ICAR)

Consultancy Project

Evaluation of BAYER fungicides against wheat diseases

Evaluation of SYNGENTA fungicides against wheat diseases

Evaluation of UPL fungicides against wheat diseases

Bio-efficacy of copper hydroxide 46% DF against bacterial leaf blight and false smut

diseases of rice

Phytotoxicity studies on meptyldinocap 35% EC for powdery mildew in pea funded by Dow

Agro Sciences India Pvt. Ltd.

Bio-efficacy of fungicides against blister blight of tea

Bio-efficacy of fungicide Tebuconazole 250 EC (Folicur EC 250) against anthracnose in

Soybean funded by Bayer Crop Science

Total Budget Outlay – > 1000 lakhs

Research Areas – Biological Control, IPM, Shisham wilt, Soil solarization, Population Biology,

Seed pathology, Mushroom etc.

Publication:

1. Books - 56

2. Research Bulletins - 20


- 22 -

3. Research Papers - >1200

4. Conceptual / Review articles - >130

5. Chapters contributed to book - >150

6. Extension literature - over (200)

(Hindi – English)

Annual Review of Phytopathology - 02

Recognition and Awards:

UNO (Rome) – Dr. Y. L. Nene

Prof. M. J. Narisimhan Academic Award (IPS) 5

Jawahar Lal Nehru Award (ICAR) 2

Pesticide India Award (ISMPP) 7

P. R. Verma Award for best Ph. D. Thesis (ISMPP) 2

Other (Hexamar, MS Pavgi, Rajendra Prasad etc.) >20

Uttaranchal Ratana 2

Education Award 2004-05” for his book “Qyksa ds jksx” 01

by the Ministry of Human Resource Development, GOI

Professional Societies and our Share:

Indian Phytopathological Societies

Presidents – 3

Zonal Presidents – 3

Indian Society of Mycology & Plant Pathology –

Presidents – 3

Vice Presidents – 1

Indian Soc. Seed Technology

Vice Presidents - 3

Science Congress

President (Agriculture Chapter) - 1

National Academy of Agricultural Sciences

Fellows - 3

Future Strategies:

Teaching: Introduction of new courses

Methods in Biological Control

Plant disease and national importance

Integrated plant disease management

Molecular plant pathology

Advances in mushroom production


- 23 -

Research thrust:

• Biological control & ICM (IPM + INM) in different crops/cropping systems

• Disease management under organic farming

• Microbial ecology

• Green chemicals

• Population biology of pathogens (including use of molecular tools)

• Induced resistance

• Exploitation of indigenous edible and medicinal mushrooms

Human Resource Development

Degree awarded

M.Sc. 313

PhD 176

Trainings organized No. Persons trained

Summer schools (ICAR) 5 136

Summer training (DBT) 1 24

International training (IRRI) 1 11 (8 countries)

Under CAS 24 498

Persons training under SGSY on Mushroom Production 1785

Out of above > 750 persons have started mushroom cultivation

Future Goal:

Ecologically sustainable management of plant diseases to ensure both food security &

safety through education, research & extension


- 24 -

Climate Change and Impacts on Plant Diseases

H.S. Tripathi & Santosh Kumar Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar- 263 145 (UK)

The rudimentary knowledge about impacts of climate change on plant patho systems, it is

impossible to predict implications for disease management with any certainty. It is prudent to

assume, however, that effects would occur chiefly through influences on host resistance or

chemical and biological control agents. Particular attention is needed to identify cases where the

efficacy of disease management may be reduced under climate change.

Host Resistance

Cultivar resistance to pathogens may become more effective because of increased static

and dynamic defenses from changes in physiology, nutritional status, and water availability.

Durability of resistance may be threatened, however, if the number of infection cycles within a

growing season increases because of one or more of the following factors: increased fecundity,

more pathogen generations per season, or a more suitable microclimate for disease development.

This may lead to more rapid evolution of aggressive pathogen races. In a pilot study, it is

monitored that evolution of Colletotrichum gloeosporioides on S. scabra under elevated CO2 , a

susceptible cultivar was grown in a controlled environment under 1 X or 2 X CO2 and inoculated

with three isolates of the pathogen. For each isolate, conidia collected from infected host tissue

were used to inoculate a second group of plants of the same cultivar. Successive groups of plants

were inoculated with conidia arising from the previous infection cycle to simulate polycyclic

disease development.

Chemical control

Climate change could affect the efficacy of crop protection chemicals in one of two ways.

First changes in temperature and precipitation may alter the dynamics of fungicide residues on the

crop foliage. Globally, climate change models project an increase in the frequency of intense

rainfall events which could result in increased fungicide wash-off and reduced control. The

interactions of precipitation frequency, intensity, and fungicide dynamics are complex, and for

certain fungicides precipitation following application may result in enhanced disease control

because of a redistribution of the active ingredient on the foliage at two intensities (6 and 30 mm h-

1) and found that the higher rate significantly reduced the fungicide residue that could be

measured with a chemical assay, but that there was no difference in disease between the two

treatments when the leaves were challenged in a bioassay with Phytophthora infestans.

Second, morpholigcal or physiological changes in crop plants resulting form growth under

elevated CO2 could uptake, translocation, and metabolism of systemic fungicides. For example,

increased thickness of the epicuticular wax layer on leaves could result in slower and/or reduced

uptake by the host, whereas increased canopy size could negatively affect spray coverage and

lead to a dilution of the active ingredient in the host tissue. Both factors would suggest lowered


- 25 -

control efficacy at higher concentrations of CO2. Conversely, increased metabolic rates because of

higher temperatures could result in faster uptake by and greater toxicity to the target organism. In

a pilot study with the herbicide chlorotoluron showed that a resistant biotype of the weed

blackgrass (Alopecurus myosuroides) became more sensitive to herbicide application when grown

under elevated CO2. It was hypothesized that this was due to changes in herbicide uptake and

translocation because of altered stomatal physiology. Despite the potential for important

interactions, no similar studies evaluating the impacts of climate change variables on physiological

aspects have been published for fungicides.

Microbial Interactions

Climate change may alter the composition and dynamics of microbial communities in aerial

and soil environments sufficiently to influence the health of plant organs . Changed microbial

population in the phyllosphere and rhizosphere may influence plant disease through natural and

augmented biological control agents. A direct effect of elevated CO2 is unlikely in the soil

environment as the microflora there is regularly exposed to levels 10 to 15 times higher than

atmospheric CO2.

Trees grown in soils of poor nutrient status, especially nitrogen, favor colonization of roots

by arbuscular mycorrhizae is not well understood, and there are conflicting reports on how it may

be influenced by the nutrient status of the plant and soil. If a lower nitrogen status of plant tissue

under increased CO2 results in more mycorrhizal colonization, this could improve plant health

through improved nutrient uptake. Similar confusion exists on the potential role of vesicular

arbuscular mycorrhizae and ectomycorrhizae in the suppression and biological control of plant

pathogens. Mycorrhizae can have positive, negative, or neutral effects on plant disease, and their

role is not well understood despite numerous studies on the subject . Clearly, the influence of

mycorrhizae on plant health under climate change requires further research.

Changes in temperature may have highly nonlinear effects on tri-trophic interactions of

host, pathogen, and bio-control agent. In wheat rise in temperature from 17 to 22°C resulted in an

increase in aphid (Sitobion avenae) reproduction by 10%; a the same time, however, predatory

activity by lady beetle (Coccinelld septempunctata) adults increased by 250%. Aphid damage was

reduced further because of earlier maturity of the crop. Similar data are not available for tri-trophic

interactions involving plant pathogens.

REFERENCE

1. The Hindu Survey of Indian Agriculture 2010. Disaster preparedness in agriculture by M.S. Swaminathan.

2. Coakley, S.M, H. Scherm and S. Chakraborty 1999.Climate change and plant Diseases management. Ann. Rev. Phytopathol. 37:399-426.

3. K.A. Garrett, S.P. Dendy, E. E. Frank, M.N. Rouse, and S. E. Travers 2006.Climatic change effects on Plant disease: Genomes to Ecosystem .Ann. Rev. Phytopathol., 44:489-509.

4. Chakraborty S. Datta S. 2003. How will plant pathogens adapt to host plant resistance at elevated co2 under a changing climate? New Phytol.159:733-742.


- 26 -

Climate Change and Food Security: Enhancing Adaptation Capabilities as a Response to Global Warming in Fragile Mountain Ecosystems

Vir Singh

Department of Environmental Science, GBPUAT&T, Pantnagar- 263 145 (Uttarakhand)

Climate change is looming large on the globe. Food security is one of the key issues that

inevitably needs to be resolved under the specters of climate change, particularly in the fragile

ecosystems, such as the Himalayan mountains, where climate change is more pronounced than in

the plain areas and where adaptation mechanisms are vocal but need to be promoted, enhanced

and implemented as an appropriate response to the climate change becoming increasingly

phenomenal.

Mountains, especially the Himalayan mountains, constitute one of the most fragile

ecosystems on planet Earth. However, their ecological and environmental functions are vital for

the mainstream world constituted largely of the plains. Biodiversity, one of the most unique

attributes of natural evolution, is a unique characteristic of the mountains. Agriculture, which has

been and continues to be one of the greatest concerns of humanity on Earth since time

immemorial, in a sense, is an art of biodiversity management. Farmers have been manipulating,

managing, enriching, promoting, and utilizing biodiversity for deriving their livelihoods for ages.

This biodiversity, and consequently mountain agriculture, owing to global warming, are under

unprecedented environmental stress these days.

Climate change is affecting – as it is bound to do – life, including human life, throughout the

globe. It is especially evident in the Himalayan mountains. The Himalayas may be referred to as

the Third Pole, for the largest amount of snows and ice is concentrated in the Greater Himalayan

area of these mountains, which is only next to the two poles. Warming in the Himalayan region is

reported to be more than the global average. It is also true that the mountain inhabitants contribute

a little to the global warming, but they are slowly heading towards being the first and perhaps the

worst victims of global warming being followed by adverse climate change. The global warming is

to severely affect water supplies, biodiversity, agricultural production and is also bound to give a

severe blow to several other factors that form the basis of a happy and content life. Severe climate

change impact on Himalayan mountains would be linked with the impending economic blues in the

plains.

What should we do amidst the gloom of climate change? This article attempts to look into

some important adaptation mechanisms that could respond to the on-going spell of climate change

and help avert the impending disaster.

Climate Change and the Himalayas

Climate change is looming large on planet earth and its impacts are being increasingly felt

in all the ecosystems in one way or the other. Its impact in the Himalayan mountains, like in the

poles, is bound to induce phenomenal changes in other ecosystems. Himalayan mountains


- 27 -

provide origin to perennial river systems in South Asia and therefore climate change repercussions

in the Himalayan Region ought to have profound implications for global climate as well as for

global economies.

Himalayan glaciers cover about three million ha, or, 17% of the global mountain area – the

largest bodies of ice outside the polar caps. Total area of Himalayan glaciers is 35,110 km2. The

total ice reserve of these glaciers is 3,735 km3, which is equivalent to 3250 km3 of fresh water.

Himalayan mountains are the source of the nine giant river systems of Asia: the Indus, Ganga,

Brahmaputra, Irrawaddy, salween, Mekong, Yangtze, Yellow and Tarim. Himalaya serves as the

water lifeline for 500 million inhabitants of the region, or about 10 percent total regional human

population (IPCC 2007).

Spell of global warming on these mountains would lead to declined water flows, drying up

of some of the important rivers, especially the rainfed ones, giving a severe blow to food

production and livelihood security of millions of people. Growing evidence shows that the glaciers

of the Himalayas are receding faster than in any other part of the world. For example, the rate of

retreat of the Gangotri glacier over the last three decades has been more than three times the

rates of the retreat during the preceding two hundred years.

Dynamics of Indian Agriculture

Fate of humanity is intertwined with agriculture, which encompasses cropping, animal

husbandry, horticulture, forestry, fishery, and all other land-related activities. Indian agriculture,

undoubtedly the oldest one in the world, has undergone three phases in its history and has now

ushered in the third phase. These are the following:

1. Primitive agriculture

2. Traditional agriculture

3. Green Revolution agriculture

4. LPG agriculture

The primitive agriculture was largely dependent on uncultivated lands. Natural forests used

to be the sources of a variety of foods. The foods were consumed uncooked. However, man had

learnt to plough the land and cultivate food grains. But there was a perfect ecological balance.

There was no stress whatsoever on nature thanks to anthropogenic activities. People depended

on diversity of foods which was derived from thousands of varieties mostly uncultivated. Primitive

agriculture never knew what venerability was. It was extremely resilient and ecologically

sustainable.

During the millennia-old history of traditional agriculture farmers maintained a balance

between uncultivated lands (forests, grasslands, rangelands, etc.) and cultivated lands. One of the

most striking features of Indian traditional agriculture was that it always embraced wonderful

biodiversity. Traditional farmers during this period developed an art of cultivating, enhancing,

conserving and utilizing biodiversity of nature. This agriculture depended on draught animal power

and organic inputs but maintained an ecological balance. Nutritive value and therapeutic qualities


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of food products were inherent in traditional food production. This agriculture was not dependent

on market to a great extent, but bartering system was very strong.

Then, towards the end of the 1960s, India ushered in the often talked-about Green

Revolution. This agriculture focused merely on high productivity which became possible with high-

yielding varieties of crops, indiscriminate use of chemical fertilizers and pesticides, excessive use

of water, and fossil-fuel powered machinery, like tractors, combine-harvesters, etc. The Green

Revolution through altered agronomic practices was one of the proudest achievements at food

production fronts turning the country from food importer to a robust food exporter. This agriculture

did not have any kind of positive relationship with the environment. Green Revolution also led to a

spurt in industries involved in the manufacture of agri-chemicals, which also contributed to

deteriorate environment.

The agriculture being vigorously pursued these days can be referred to as the

liberalization, privatization and globalization (LPG) agriculture, which, in fact, is an ‘improved’

version of the Green Revolution. The LPG agriculture is biotechnology-driven and is governed by

global market. This is closely allied into global industry and is structured for huge profits by the

corporate sector. New crop cultivars which nature had ‘failed’ to evolve have been created using

genetic engineering. Genetically modified organisms (GMOs) of major crops are on way to occupy

centre-stage of agriculture. After non-food crop of Bt cotton, Bt food crops are in the pipeline. The

LPG agriculture ignores environmental issues. This agriculture is still in its infancy but is all set to

have unending implications for environment and public health.

Vulnerability of Contemporary Agriculture

Never before in the history has Indian agriculture been as vulnerable and uncertainty-

ridden as it is today. A glimpse of the dynamics of Indian agriculture reveals that it has

systematically deviated away from its very base, that is, the environment—the prop that nourishes

all biological resources. Today’s agriculture is valued against the prices it fetches from the market,

especially the global market. Its contribution to human health and welfare, ecological integrity,

resilience of nature, etc. are grossly neglected.

The agriculture had begun going anti-nature since the inception of the Green Revolution,

which was based on the so-called high-yielding varieties, monocultures, indiscriminate applications

of chemical fertilizers and pesticides and over-exploitation of water resources for irrigation. None

of the farming practices associated with the Green Revolution was environment-friendly. The

Green Revolution turned ghastly for small and marginal farmers as well as for the agro-

ecosystems it operated in. It poisoned virtually all components of the environment – biotic as well

as abiotic, and lands, soils, waters and atmosphere. It started poisoning the whole civilization as

well as all living beings.

All kinds of epidemics are virtually linked with agriculture. Healthy food ensures healthy

society. Contaminated food ensures a sick society. A sick society cannot be a sustainable society.

If the very basis of life, i.e. the producers, become poisoned, all the food chains and food webs in


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all ecosystems are inevitable to be poisoned. Thus a wrong agriculture becomes a root cause of

all the ills of a society.

The kind of agriculture being pursued these days (the LPG agriculture) is the climax of

contaminated agriculture. Introduction of alien genes in a plant is a classical example of genetic

pollution. Bt crops are able to save themselves because the introduced Bt genes produce poison

within the plant that is capable of killing insects. But this is the worst possible nature-annihilating

method of pest control. The ecological means of plant protection call for management, not

extermination, of insect pests. If all the insects are wiped out and done to extinction as the

genetically modified crops are set to do, this would be a death knell for nature. The genetically

modified organisms (GMOs) do not make any difference between useful and harmful insects (of

course, there is nothing like harmful in nature). Pollinators, amidst the enormous diversity of

insects, will also be wiped out when large areas of cultivated land are covered by GM crops. This

situation would bring death warrant for humanity, for the extermination of pollinators would mean

failure of crop production to a great extent.

Agriculture has not just been a source of livelihood, human survival, progress and

sustainability, but also a way of life, a potent symbol of a civilization, a culture and a philosophy.

With the retrogression of agriculture, we are also bound to witness crumbling of Indian ethos

reflected in basic Indian philosophy, the agro-ecophilosophy. Making agriculture healthy, vibrant

and sustainable is not only necessary but also an imperative for a healthy, vibrant and sustainable

society. It is also an imperative of our destiny.

Mainstream Agriculture vs Mountain Agriculture

Mountain ecosystems are fragile and witness very high degree of biodiversity. Further,

mountain ecosystems play very crucial role which the mainstream plain areas cannot. Mountain

ecosystems are altogether different from the plains and so is mountain agriculture. Despite

massive agricultural transformations having taken place all over the world, mountain people have

not brought transformation to their agriculture to an appreciable extent. Mountain agriculture,

despite intensive institutional intervention, by and large stays traditional. The cropping

accommodates biodiversity of plants, both at species and genetic level which change according to

the type of agro-ecosystem. Some of the striking characteristics of the mainstream and mountain

characteristics are shown in Table 1.

Table 1: Some features of mainstream and mountain agriculture

Features Mainstream agriculture Mountain agriculture

Fragility Moderate High

Farming system Absent Present

Diversity/ heterogeneity Minimum High to extreme

Complexity Less High to extreme

Vulnerability high Least


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Resilience Low High

Water use efficiency of crops

poor high

Inputs External Internal

Productivity Moderate to high Moderate

Sustainability Poor High

Natural Adaptation Capability in Mountain Agriculture

An agricultural system that embraces features of a sustainable system also carries

characteristics of adaptation capabilities. In other words, a more adapted agricultural system is

more sustainable. And also, a more adaptable agriculture is more sustainable. In order to be

sustainable, agriculture should be:

1. Ecologically sound,

2. Regenerative,

3. Economically viable, and

4. Socially just.

Mountain agriculture, in fact, is characterized by these traits and, therefore, carries traits of

a sustainable agriculture. These have been elaborated in Table 2 and have also been

demonstrated in Fig. 1. All the four traits of a sustainable agriculture are intertwined together. If

one trait misses, the very base of sustainability is shrunk. Each trait of a sustainable agriculture, as

in case of the mountain agriculture, has many indicators of sustainability.

Fig. 1: Traits of sustainable agriculture intertwined into a complex whole – High degree of adaptations


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Table 2: Indicators of sustainability associated with mountain agriculture

Sustainability trait Sustainability Indicators associated with each sustainability trait

Ecologically sound Larger forest-cropland ratio High degree of biodiversity and complexity Living soil Integration with trees and livestock Energy efficient Resilient Cyclic flow of nutrients Organic inputs Resource enhancing and conservation-oriented

Economically viable Linkages with market Remunerative production Value addition

Socially just Accessibility to food resources by all Food and nutrition security for all Recognition and promotion of traditional knowledge systems and people's innovations Good governance

Regenerative Energy saving and conserving Resuscitation and recharging of water sources Enhanced biodiversity Enrichment of soil Increased rate of carbon sequestration Contribution to global warming alleviation and climate change mitigation

Matrix of Mountain Agriculture

A mountain agro-ecosystem comprises uncultivated land (often forest or rangeland),

cropland, livestock and households as its integrated parts (Fig. 2). Uncultivated land serves as a

natural reserve of biodiversity, energy, water and nutrients. This is the largest component of a

mountain agro-ecosystem. Forests are ecologically more stable than the croplands, hence more

resilient and less vulnerable. They do not require an input of nutrients or water. The water received

through natural precipitation is conserved and brought into circulation by the forests. Forests are

rich reserves of nutrients that also nourish croplands. Forests are capable of regeneration. If forest

products are exploited judiciously, they would be capable to regenerate themselves. Higher the

measure of biodiversity in a forest ecosystem, greater would be its role in nourishing the

croplands. In addition to the ecosystem functions vital for the sustainability of an agro-ecosystem,

a forest is also capable of producing very large number of edible food products, such as wild fruits,

buds, flowers, seeds, beans, mushrooms, etc. apart from valuable medicinal plants and several

other plants of economic value.


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Fig. 2: Matrix of a mountain agro-ecosystem

Cropland is the core land serving to produce cultivated foods. This land is constantly

nourished by the nutrient stock in a forest ecosystem, either directly (such as through the input of

mulch) or through livestock (through manure application).

Mountain agriculture is a mixed agriculture and gives prominent place for the livestock.

Livestock play crucial role in transferring nutrients from a forest/ rangeland ecosystem to a

cropland. The latter are more fragile than the forests. They also help in recycling of nutrients into

croplands. Their main contribution is to supply draught power needed for ploughing, leveling,

puddling, inter-culture operations, etc. apart from yielding milk as one of the most important food

items for human beings. In addition, they also serve as crucial part of the local cultures and as a

cushion against socio-economic fluctuations. Livestock role is vital for the very sustainability of

mountain agriculture.

A village is a cluster of households, who are the custodians and managers of an agro-

ecosystem. They are the farmers who have been at the heart of the evolution of Indian agriculture.

Mountain farmers are a rich repository of Indian wisdom. They are equipped with the knowledge

and technologies by means of which nature and its biodiversity are conserved, enhanced and

sustainably utilized. The farmers have never kept their farming systems in static state. They have

changed themselves and their systems as per specific circumstances. They have evolved

strategies as per the local specificities and that can cope up with adverse circumstances.

Food Security Concept in Mountain Context

Just three food crops – wheat, rice, and maize – meet about 75 percent of the total energy


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humanity worldwide needs for sustenance. This perhaps is the most precarious situation relating

to food security on a global scale. Any imbalance in the production of these three food grains –

due to some epidemic or some ominous changes in climate, for example – might pose a serious

threat to the very survival of human race. Some unique food crops endemic to certain regions are

being squeezed out of cultivation practices to give a room for the alien cultivars and some non-

food cash crops having “high” market value.

The concept of food security – the ability of a household to get access to enough food for

all its members, either by producing it or by earning enough to buy it – has been given new

meaning in the food-deficit regions of the Himalayas where farmers are being encouraged to grow

high value cash crops which will contribute to their incomes and thus their food purchasing power.

This “new meaning”, in fact is a bid to amalgamate the local realities with the globalisation

process. This emphasises only the “food purchase power”, a mere political dimension of “food

security” indiscriminately imposing a dependence on market. It has no respect for local cultures

and reverential attitude towards pristine marginal ecosystems like the mountains. “High-value”

cash crops are not the ones mountain farmers have been growing for millennia. These are the

ones that require exploitation of unique ecological niches wantonly to serve the interests of the

global elites in the first place.

There can be no standard approach for food security on a global scale. Food security

without cultural roots is not sustainable. And the current market-linked concept of food security

being debated the world over has no cultural roots; i.e., it has no consideration of specific

ecosystem features and the communities evolved therein. Food situation is tied with local realities.

Local considerations rather than global “standards” would add to the essential cultural dimension

to food security. Mountain farmers are accustomed to grow diversity of food in their habitats, in

harmony with specific ecological niches for specific products and activities. Diversity in sources

providing food is the very essence of the food security of mountain cultures. A community has its

own food habits. As such, there exists an enormous diversity in food habits of peoples in the world.

You cannot ensure food security of a Westerner by plenty of rice for him. A vegetarian cannot be

provided food security through meat. Food security in Uttarakhand would be meaningless without

Dal-Bhaat. A community’s food habits match with the food production system it has evolved in its

habitats. Provision of food as per food habits is a must for one’s physical and mental development

and psychological satisfaction.

Food security of masses in India as of today is tied with just two types of food grains –

wheat and rice – supplied to the vulnerable sections of the society through public distribution

system (PDS). PDS, in fact, appears to have become the only political perception of “food

security”. Inaccessibility- and fragility-ridden mountain areas require altogether a different

approach for acquiring sustainability and food security. Majority of the population in Uttarakhand is

land-based. They are small and marginal farmers depending on a variety of food-providing

sources: the CPRs, the croplands, the livestock, and the water bodies.


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Diversified agriculture is the best bet for reducing risks and enhancing the degree of

security. The marginal farmers exactly do the same. The gains accrued to the small and marginal

farmers through diversified agriculture, however, are limited by the size of the arable land they

own. But, it is not the arable land alone that could serve as the base for food security as is

perceived in the context of the plains. Mountain farmers give equal, rather greater, importance to

the CPRs, other marginal ecosystems (alpine meadows, for example), and water sources.

Availability of water on sustained basis is a prerequisite for sustainable food security. For

water security, fragile mountains obviously require high density of climax vegetation with

enormous diversity of all types of plants – trees, shrubs, herbs, creepers, etc. Such vegetation, in

addition to contribute biomass to cropland so crucial for soil fertility management, also responds to

the problems associated with fragility of the Himalayan mountain ecosystems.

High degree of inaccessibility of the mountain areas calls for decentralised economies.

Dependence on a central market place for agricultural inputs and food grains is not only difficult

and energy consuming but also not conducive to the very philosophy of food security.

Self-sufficiency in food has to be the foremost target to food security in mountain

ecosystems. And for this to achieve, farming system approach of food production involving local

farming cultures should be the focal point of our strategies.

In marginal areas, food self-sufficiency of farming households should be preferred over

food purchase power. Farmers have ample opportunities for raising their incomes through what

their ecological niches can offer. These can range from off-season vegetables, to vegetable seed

production, to floriculture, to medicinal and aromatic plants, and so on. These cash-promising

activities would raise their purchasing power. However, these should be compatible with the food

self-sufficiency in the region.

Adaptation Capabilities of Mountain Agriculture

The farming system the local farmers have developed is characterized by specific

adaptation mechanisms. Farmers through their specific management practices have ensured

maintenance of the sustainability characteristics of a farming system. These are ensured through

energy, nutrient, water and gaseous flows within the ecosystem (Fig. 3). These flows are

indispensable for ecological integrity of the farming system.

Mountain agriculture adaptation capabilities can be counted at two points, viz., resource

base and farmers’ response. Resource base imparting adaptation capability includes common

property resources, landraces, Baranaaja culture, and livestock. The farmers’ response includes

farming system approach, community based farming, on-farm biodiversity conservation, and

farmers’ knowledge, strategies and innovations. These are elaborated in Table 3 and depicted in

Fig. 4.


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Fig. 3. A mountain agro-ecosystem: linkages between components/ subsystems, nutrient and water flows maintain ecological integrity and sustainability of the food production system

Table 3: Mountain agriculture capabilities and their attributes

Mountain agriculture capability

Attributes of the adaptation capability

RESOURCE BASE

Common property resources

Vital for the ecological integrity of an agro-ecosystem

Micro-climate maintenance

Repository of nutrients, energy and water/ moisture

Natural fodder bank for livestock

Wild fruits, nuts, edible flowers, buds, mushrooms, uncultivated vegetables, seeds, pods, beans, medicinal and aromatic plants, honey, etc.

Supply of raw material for house construction, domestic fuel, agricultural implements and tools and cottage industries

Landraces Extremely adapted for the local conditions

High genetic diversity

Nutritive value, specific aroma and taste

Medicinal value of some crops


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Baranaaja culture

Cultivation of biodiversity

Soil fertility management

Insect-pest management

Production of high energy, protein- and nutrient-rich foods (millets, pseudo-cereals, pulses, beans, etc.)

Resistance against drought conditions

Use of degraded, nutrient-poor soils

Spatial and temporal utilization of cultivated land

Livestock Diversification of food resources

Utilisation of high fibrous diet

Mediation for nutrients from ecologically more stable forest ecosystem to fragile croplands

Recycling of nutrients into croplands

Supply of draught power for ploughing, leveling, puddling, inter-culture, etc.

Acting as cushions against economic adversity

FARMERS’ RESPONSE

Farming system approach Ecological stability, reduced vulnerability, enhanced resilience

Diversification of food production

Provision of inputs from within the system

Risk reduction

Sustainability operation

Community based farming Participation of whole community

Democratic decision making in resource management

Availability of precious resources such as seeds at reasonable rates, or free of cost, or through bartering

Free exchange of resources (e.g., ploughshare, germplasm, bullocks, etc.)

More emphasis on innovative approaches to resource management

Involvement of community’s feelings, aspirations and future dreams

Enhancement of social cohesion

On-farm biodiversity conservation

Maintenance of the inherent/ natural characters of germplasm

Minimisation of risks of species’ extinction

Conservation of biodiversity in a natural way

Control of farming community on resource conservation and utilization

Reduced dependence on market/ corporate sector for expensive and often unaffordable germplams

Maintenance of endemic diversity in nature

Farmers’ knowledge, strategies, innovations

Conservation, transfer, articulation and promotion of traditional community knowledge

Articulation of traditional wisdom in land-based activities

Risk minimization tactics of farming

Experimentation according to local site characteristics

Application of world view of agriculture

Applications of community’s own research methodologies and technology testing


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Fig. 4. Adaptation capability of mountain agriculture

The Cycle of Sustainability

There are three principles of sustainability operationalisation—Living soil, biodiversity and

cyclic flow pattern of nutrients. Mountain farmers manage the soil in such a way that it should

continue to be replenished by nutrients through manure, recycling, in-situ fertilization, mixed

cropping, mulching and other management practices. They still adhere to an old adage – don’t

feed the plant, feed the soil which feeds the plant. Farmers cultivate as much agro-biodiversity as

could be possible in a particular area. They also manage the natural biodiversity in uncultivated

areas (forests, grasslands, rangelands, etc.). This biodiversity is a key to sustainability. Higher the

degree of biodiversity, higher the level of sustainability. Farmers also manage cyclic flows of

nutrients. Whatever nutrients are extracted from croplands are cycled into the same soil through

manure. The soil fertility is further enhanced by supplementing the nutrients from forest soil.

Fig. 5. Cycle of sustainability


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This wonderful practice of farming in mountain areas is an example of farmers’

management of sustainability (Fig. 5), which is a natural adaptation capability in the region.

Agro-ecophilosophy and Sustainable Biosphere

Agriculture, in essence, is an articulation of a philosophy we can call agro-ecophilosophy.

Agro-ecophilosophy is a meaningful fusion of agriculture, ecology and philosophy. This philosophy

is life-enhancing and has been at the heart of Indian ethos for millennia and embraces reverential

attitude towards nature, ecosystems, and whole life.

Agro-ecophilosophy provides basis for ecological consciousness which is a pre-requisite of

ecological responsibility. Ecological responsibility prepares a ground for pertinent ecological

actions, which are essentially the life-enhancing actions (biodiversity conservation and

enhancement, for example). Ecological action directs us for ecological justice, which, in turn,

provides an atmosphere of ecological culture. The ecological culture would help create an

ecological balance. And ecological balance is an absolute need for a sustainable biosphere (Fig

6).

Mountain farming communities have been creating eco-philosophies for centuries.

Himalayas’ serenity, environmental sacredness and scenic beauty have been inspiring them to

create and implement eco-philosophies. Mountain agriculture in its traditional form still sings a

song of mountain farmers’ philosophy. The agro-ecophilosophy is potent enough to heal the Earth

and to restore our glorious agriculture even in the era of global warming and climate change.

Ecological balance

Ecological culture

Ecological justice

Ecological action

Ecological responsibility

Ecological consciousness

Agro-ecophilosophy

Fig. 6. Agro-ecophilosophy, agri-culture and sustainable biosphere


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Conclusion

The natural and farmer-evolved adaptation capabilities of mountain agriculture, as

discussed in this paper, serve as a part of our strategy of rising against global warming in our

times. The mountain culture has not undergone as much drastic change as the mainstream

agriculture. With specific characteristics of the mountain resource base and farmers’ traditional

strategies implemented honestly on a massive scale, we would be able to regenerate the

productive potential of the traditional mountain agriculture. We need to capture and absorb basic

philosophical elements of the traditional mountain agriculture, i.e., the agro-ecophilosophy, to

regenerate and restore the kind of agriculture which could produce a variety of plentiful foods to

nourish local communities as well as the people in the distant areas. In this way we would not only

rise against the global warming but would also come out with a glorious victory to restore the

original evolutionary gesture of our nature.


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Disease Management in Precision Farming

V.S. Pundhir

Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar- 263 145 (Uttarakhand)

Precision Farming has emerged as management practice with the potential to increase profits by;

utilizing more precisely agricultural resources.

Precision Farming: the factors are important

Yield potential of variety

Yield capacity of field





Precise Management of following input variables is important:

Cultivar selection

Tillage practices

Irrigation scheduling

Disease / Pest management

Developing database

Options (agents/methods) have been developed to eradicate / reduce the pest populations,

so as they do not cause physical and economic losses to plants that are required for well

being and sustenance of life (human race) on the planet.

Present emphasis is to do the same things more precisely

Following Practices are Adopted in Precision Farming

A. Judicious Use of Pesticides

Disease forecasting

Using ETL for pesticide spray

Management of resistant strains

Adoption of IPM package deal

B. Crop Rotation / Sequence

vegetable crops rotated with rice effective in management of root-knot nematodes in

vegetables

long rotation of potato with cereals & non-host vegetables (cole) helps in bacterial wilt

management

rice crop after cotton reduces Verticillium dahliae

green manuring has dual effects

C. Soil Solarization

Successful Management

Damping-off of seedlings, root rots, stem rots,


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fruit rots, wilts and blights (Pythium, Phytophthora, Fusarium, Sclerotium,

Rhizoctonia,Sclerotinia, Verticillium, Ditylenchus, Globodera, Heterodera, Meloidogyne,

Clavibacter)

WEEDS : Amaranthus spp. Amsickia, Anagallis, Avena, Chenopodium, Convolunalus,

Cynodon, Digitaria, Echinochloacrus, Eleusine, Fumaria, Lactuca, Linum, Montia,

Notabaris, Phalaris, Poa, Portulaca, Sisymbrium, Senecio, Xenthium

D. Precise Crop Culture

Time of planting (late blight)

Method of planting (ridge planting)

Seed rate / population density (wilts)

Seed placement (damping-off)

Host Nutrition: (Balanced)

o deficiencies/toxicities & corrections

o amount & form of Nitrogen (leaf spots)

o P & K imparts resistance (spots/blights/mildews)

E. Water Management

Water is vital for activities of host & pathogens

Soil moisture: damping-off/seed-root rots & wilts

Availability of irrigation affects type of crops grown, thus indirectly affects pathogen

(survival / spread) and resulting diseases

wet soils favour club root of crucifers & silver scurf of potato while dry soils favour white

mold of onion, common scurf of potato and Fussarium wilts

Dry soils suppress zoo-sporic fungi

Irrigation water is potential agent for transport/distribution of inoculum

Time & type of irrigation also influence

F. Organic Amendment of Soil: economic, hazard free and eco-friendly

Decomposable organic matter or green manuring manifold benefits

Soil physical environment (pH, C/N, CO2)

Soil chemical env. (decomposition products)

Soil biological environment: Antagonism (fungistasis, parasitism, predation, antibiosis and

competition etc.)

Induced host resistance / tolerance

G. Precise Practices and Disease Management

Method Pathogen managed Crop

Crop rotation Cephalosporium gramineum G. graminis var. tritici

Wheat Wheat

Crop spacing Sclerotinia sclerotiorum Dry beans

Decoy crop Spongospora subterranea Potato


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Fallow Pseudomonas solanacearum Banana

Fertilizer practices F. oxysporum f. sp. phaseoli Dry bean

Flooding F. oxysporum f. sp. cubense Banana

Monoculture Streptomyces scabies G. graminis var. tritici

Potato Wheat

Organic amendments fungi and nematodes Crops

pH adjustment Plasmodiophora brassicae Streptomyces scabies

Crucifers Potato

Tillage Sclerotium rolfsii Peanut

Time of Planting Fusarium roseum Tilletia controversa

Wheat Wheat

Trap crop Meloidogyne spp. Crops

Water management Phytophthora spp. Macrophomina phaseolina

Walnut, Cherry Sorghum

H. Survey and Surveillance

Survey means “to view the situation comprehensively and extensively at different

periodicity”

Surveillance is “vigilant supervision of a situation” (to keep close and constant watch)

Plant disease surveys are basic guide to disease progress that helps in fixing the priorities

May serve as forewarning for certain actions

It also tells about the impact of the changing CLIMTE , agricultural technology & pd

management tools.

I. Precision in disease forecasting will focus on the following;

1st generation forecast:

based on weather data,

focusing on time of first spray

2nd generation forecast:

Location and magnitude of pathogen

Weather data

Cultivar resistance

Survival of sporangia from out side the fields

Fungicides resistance and micro-processors for

Recording and processing of data.


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Climate Change and Mitigatory Measures with Reference to Hill Agriculture

Uma Melkania

Department of Environmental Science, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Background

Global warming refers to warming of the earth resulting from build up of greenhouse gases

of anthropogenic origin in the atmosphere. The impact of climate change due to global warming is

disproportionately higher for developing countries and the poor of all countries due to higher

physical exposure and dependency on natural resources for their livelihood.

Contribution of Greenhouse gases emission in different sectors shows that agriculture contributes

13% of greenhouse gases as compared to other sectors but faces the impact generated by other

sector as well (Fig.1).

Source: ENVIS, NBRI 2010

Impact of Climate Change:

Impact on crop yield: Studies have shown that the climate change will decrease or increase crop

yield in various ways depending on the latitude of the area, altitude of the areas, precipitation

changes evapotranspiration changes and temperature changes. Temperature increase

significantly affects higher photosynthesis, respiration and transpiration rates, triggered flowering

etc. Northward expansion of suitable cropping areas with changes in radiation and temperature is

also expected. The incidences of various diseases have also been observed.

Positive effects of CO2 enrichment on yield and water use efficiency have been observed. It is

recorded that 2-30C temperature rise is good for crop yield but crop yield decreases at higher

temperature. The simulation models studies in India have shown that with increase in temperature,

regardless of CO2 fertilization risk of hunger is a big challenge to be faced (ENVIS 2010). For hill


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agroecosystems the use of lesser known species being grown by inhabitants using their traditional

knowledge can be encouraged. Climate adapted crops such as varieties of major crop resistant to

heat, drought, submergence and salty water could be cultivated. (FAO, 2011)

Threats to Ecosystem services: The mountainous areas serve various types of ecosystem

services in the form of rich forest areas, origin place of many rivers, guarding national boundaries,

watersheds and picturesque landscapes due to the threats of climate change and anthropogenic

pressure. The ecosystem services are also being affected negatively posing threat to ecosystem

health and viability of agroecosystem in hills. Efforts are required for proper valuation of ecosystem

services.

Threats to Biodiversity: The hill ecosystems are the repositories of biodiversity which directly

related with the livelihood of inhabitants in terms of food, medicine, resource for small-scale

industries, mixed crops, underutilized crops, their races and wild relatives and intangible benefit in

terms of ecosystem/environmental stability. Changing climatic conditions may affect the

ecosystem biodiversity through affecting tangible and non-tangible benefits. More efforts are

required to conserve biodiversity in forest and agroecosystem in these hilly areas.

The expected impact of climate change across forest and agriculture sectors mentioned in a report

from Ministry of Environment and Forests (Anonymous 2010) is shown in table 1.

Table 1: Expected impacts of climate change across forestry and agriculture sectors. (Anonymous

2010)

Sector Physical and ecological impacts

Socio-economic impacts

Cross-Cutting issues

Vulnerable areas/Sectors

Forests A study by the Indian Institute of Science shows a large-scale shift in forest types in India under current and future climate scenarios

In India nearly 200,000 villages rely on forests and forest products for their livelihood. The supply of forest products and consequently, the livelihoods of forest-dependent communities

Change in biodiversity (endangered species diversity) and associated implications on ecological balance

Forests

Agriculture In India, it is estimated that a temperature rise of 20C could lower the yields of staple crops such as wheat and rice by 10% and reduce farm revenues

Endangered livelihoods of agriculture-dependent communities and implications on food security

Changes in soil properties and distribution and frequency of infestations by pests, insects and diseases

Farming

With the increasing threat of climate change at world level several measures have been

taken at various levels through adopting policies, acts and rules to combat the effect. One of the

important efforts to deal with this problem was during “Earth Summit” (United Nations Conference

in Environment & Development) held in Rio De Janeiro in the year 1992. As a result of this


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Intergovernmental Panel on climate change (IPCC) was formulated and Kyoto protocol was made

an act on 16th Feb, 2005 including the mechanism of CDM i.e. clean development mechanism.

Under this there is the provision of adaptive and mitigatory measure. The adaptive measures helps

human and natural systems to adjust to climate change such as finding resistant and resilient crop

varieties, tree species with good coppicing capacity, regenerating capacity etc. The mitigatory

measures help to reduce net carbon emission and limit long-term climate changes. Considering

the interconnected of this the mitigatory measures have to be adopted by various sectors as below

i.e.

1. Energy Sector: Under this energy efficiency through improved techniques need to be

achieved.

2. Forestry Sector: The practices of afforestation, avoided deforestation, assisted natural

degradation and environmentally sound forest management have to be addressed.

3. Agriculture Sector: The cropland management has to be adopted through carbon

sequestration, management of nutrients, tillage, residues, soil and agroforestry and water

use efficiency.

Hill Agriculture

Peculiarities

Traditional agriculture in the hills is organic, low in the use of fossil fuel based inputs and,

therefore, results in lower greenhouse gas (GHG) emissions. Himalayan agriculture is based on

traditional approaches exhibiting close interdependence among key resources- land, livestock, and

forests. Agriculture crop diversity, as well as genetic diversity within a single crop, is the key

feature of mountain agricultures. Scientists opine that such biodiversity may also enable

production systems to survive changes in the climate.

There has been an almost total absence of inputs emanating from research on small area and

eco-friendly, high yielding, varieties of rain-fed mountain crops (Anonymous 2010)

The National Action plan on climate change has mentioned that The National Mission for

Sustaining the Himalayan Ecosystem is vital to the ecological security of the Indian landmass,

through providing forest cover, feeding perennial rivers that are the source of drinking water,

irrigation and hydropower, conserving biodiversity, providing a rich base of high value agriculture,

and spectacular landscapes for sustainable tourism. At the same time, climate change may

adversely impact the Himalayan ecosystem through increased temperature, altered precipitation

patterns, and episodes of drought. The National Environment Policy, 2006, interalia provides for

the following relevant measures for conservation of mountain ecosystems:

Adopt appropriate land-use planning and water-shed management practices for

sustainable development of mountain ecosystems.

Adopt “best practice” norms for infrastructure construction in mountain regions to avoid or

minimize damage to sensitive ecosystems and despoiling of landscapes


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Encourage cultivation of traditional varieties of crops and horticulture by promotion of

organic farming enabling farmers to realize a price premium. (National Action Plan on

Climate Change 2010)

Several studies have reported that viability of agroecosystem in hills depend on the viability

of forest ecosystems. The cause has been explained as below due to the peculiarity of hill

agroecosystem in several ways at below:

Mainly rainfed agriculture for subsistence.

Due to topographical aspect cultivation is terrace agriculture, and valley cultivation.

Agricultural productivity alone is not sufficient to fulfil the livelihood feeds of inhabitants.

Their dependency on forest ecosystem is in the form of firewood, fodder and other non-

timber forest produces. Animal husbandry is also the past of hill agriculture as the

mechanization of hill agriculture is not possible due to topographical factors and the

ploughing is being done to cultivate the land. Meanwhile, the farmyard manure is from

livestock is being used in the agriculture to conserve soil and water or for the better health

of ecosystem.

Carbon Sequestration and Agroecosystem

• Carbon sequestration is an important approach for mitigating the greenhouse effect on

climate and terrestrial carbon sequestration is the process through which CO2 from the

atmosphere is absorbed by trees, plants and crops through photosynthesis, and stored as

carbon in biomass (tree trunks, branches, foliage and roots) and soils.

• The largest pool of actively cycling C in terrestrial ecosystems is the soil. Carbon flows

between soil and the atmosphere through the paired process of photosynthesis and

respiration.

• The impact of cultivated land on climate is multiple and significant. First, compared with

forested sites, agricultural land is characterized by a greater albedo, lower soil roughness

and soil humidity variations that influence sensible and latent heat exchanges. Crops

constitute the most important biospheric source of carbon dioxide (CO2), resulting from plant

respiration and soil organic matter decomposition. Changes in agricultural practices are

being considered as possible ways to mitigate climate change by increasing carbon storage

in crop soils.

• The amount of carbon stored in and emitted or removed from the agroecosystem depends

on the crop type, management practices, and soil and climate variables. Annual crops are

harvested each year, and therefore provide no long-term storage of carbon in aboveground

biomass, but soils can sequestrate atmospheric CO2 when large quantities of crop residues

and organic manure are returned to the soil.

• Carbon stocks in agricultural soils can be significant. Changes in stocks can occur in

conjunction with soil properties and management practices, including crop type and rotation,


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tillage, drainage, residue management and organic amendments.

• The carbon budget of agroecosystems is important in the global terrestrial C cycle but has

been difficult to quantify on a larger scale due to spatial and temporal variations in climate,

soils and agricultural practices

• Research during the past few decades has demonstrated the significant contribution that

conservation agricultural systems can have on reducing emission of greenhouse gases, as

well as sequestering carbon in soil as organic matter.

• The soil organic carbon (SOC) content of agricultural ecosystems has been found to depend

on land use, cultural management, fertilizer application, harvest features, residues

management, microclimate and soil tillage.

• The quantity of soil carbon present is controlled by a complex interaction of processes

determined by carbon inputs and decomposition rates. Factors controlling the quantity of

organic matter in soil include temperature, moisture, oxygen, pH, nutrient supply, clay

content and mineralogy.

REFERENCES

1. Anonymous 2010.To look into problems of hill states and hill areas and to suggest ways to ensure that these states and areas do not suffer in any way because of their peculiarities. Planning Commission and G.B.Pant Institute of Himalayan Environment and Development, Kosi Katarmal Almora.

2. Anonymous 2009-2010. Report to the people on Environment and Forests. MOE&F, Govt. of India 2008.

3. National Action Plan on Climate Change, Ministry of Environment MOE&F, Govt. of India 2008.

4. Parsai Gargi, Prepare for long term climate change on food production; FAO.

5. The Hindu 1st April 2011

6. Anonymous 2010. National Botanical Research Institute Lucknow ENVIS (NBRI) MOE&F 6: Newsletter.


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Climate Change and Plant Diseases

N.S. Murty Department of Agrometereology, G.B.P.U.A.&T., Pantnagar- 263 145 (Uttarakhand)

Worldwide concerns have been rising about climatic change and potential changes in crop

yields and production systems. Such concerns include the ability to accommodate these

uncertainities in order to ensure an adequate food supply for ever increasing population. Crop

yields and changes in productivity due to climate change will vary considerably across regions and

among localities, thus changing the patterns of production in general, productivity is projected to

increase in middle to high latitudes, depending on crop type, growing season, changes in

temperature regime, and seasonality of precipitation. Most researchers believe that higher

temperatures and droughts caused by climate change will depress crop yields in many places in

the coming decades.

Impact of Climate Change on Crop Production

In the coming decades, global agriculture faces the prospect of a changing climate as well

as the challenge to feed the world's population, projected to be double its present level by about

the year 2060 .The prospective climate change is global warming (with associated changes in

hydrological regimes and other climatic variables) induced by the increasing concentration of

active greenhouse gases. Despite of technological advances such as improved crop varieties and

irrigation systems, weather and climate are still key factors in agricultural productivity. For

example, weak monsoon rains in 1987 caused large shortfalls in crop production in India,

Bangladesh, and Pakistan, contributing to reverting to wheat imports by India and Pakistan (World

Food Institute, 1988). The 1980s also saw the continuing deterioration of food production in Africa,

caused in part by persistent drought and low production potential, and international relief efforts to

prevent widespread famine. The effects of climate on agriculture in individual countries cannot be

considered in isolation. Agricultural trade has grown dramatically in recent decades and now

provides significant increments of national food supplies to major importing nations and substantial

income for major exporting nations These examples emphasize the close links between agriculture

and climate, the international nature of food trade and food security, and the need to consider the

impacts of climate change in a global context.

Climate change induced by increasing greenhouse gases is likely to affect crop yields differently

from region to region across the globe.

The greenhouse gases CH4, N2O and chlorofluorocarbons (CFCs) have no known direct

effects on plant physiological processes. They only change global temperature and are therefore

not discussed further. Instead, concentration should be on the effects of increased CO2 ,

tropospheric O3, increased UV-B through depleted stratospheric ozone, increased temperatures

and the associated intensification of the hydrological cycle.

In general, higher temperatures are associated with higher radiation and higher water use.


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It is relatively difficult to separate the physiological effects (at the level of plants and plant organs)

of temperatures from the ecological ones. There are both positive and negative impacts at two

levels, and only crop- and site-specific simulation can assess the global 'net' effect of temperature

increases. It is generally agreed that: rising temperatures - now estimated to be 0.2°C per

decade, or 1 °C by 2040 with smallest increase in tropics would diminish the yields of some crops,

especially if night temperatures are increased. Higher cold-season temperatures may lead to

earlier ripening of annual crops, diminishing yield per crop, but would allow for more crops per year

due to lengthening of the growing season.

Effect of increasing temperature: Indian Scenario

Agriculture represents a core part of the Indian economy and provides food and livelihood

activities to much of the Indian population. The agricultural sector represents 35% of India’s Gross

National Product (GNP) and as such plays a crucial role in the country’s development. Food grain

production quadrupled during the post-independence era; this growth is projected to continue. The

impact of climate change on agriculture could result in problems with food security and may

threaten the livelihood activities. Climate change can affect crop yields (both positively and

negatively), as well as the types of crops that can be grown in certain areas, by impacting

agricultural inputs such as water for irrigation, amounts of solar radiation that affect plant growth,

as well as the prevalence of pests. While the magnitude of impact varies greatly by region, climate

change is expected to impact on agricultural productivity and shifting crop patterns. The policy

implications are wide-reaching, as changes in agriculture could affect food security, trade policy,

livelihood activities and water conservation issues, impacting large portions of the population.

According to a recent report of IPCC (2007) Crop productivity will fall, especially in non-

irrigated lands, as temperatures rise for all of South Asia by as much as 1.2 degrees C on

average. Food and Agriculture Organization (FAO) said India could lose as much as 125 million

tones of its rainfed cereal production. In contrast, the industrialized countries are likely to gain in

production potential. On the contrary, at lower latitudes, especially in the seasonally dry tropics,

crop yield potential is likely to decline for even small global temperature rises, which would

increase the risk of hunger. Greater frequency of droughts and floods would affect local production

negatively, especially in subsistence sectors at low latitudes. Rising temperature, due to global

warming, will affect the amount of rainfall and the pattern of monsoon season. Because India’s

economy is heavily based on agriculture, the importance of accurately predicting the timing and

severity of monsoons is extremely important. For example, if monsoon rains do not arrive on time,

farmers will be forced to wait and run the risk of planting their crops late.. If monsoon rains are too

severe, seedlings that were planted could be damaged. A number of recent scientific studies have

acknowledged this risk and have examined the factors which create and influence monsoons in an

attempt to better predict future monsoon seasons.

Effect on Plant diseases:

Coakley et al. concluded that the effects of climate change on plant disease management


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may be less important than changes in land-use patterns, transgenic technologies, and availability

of chemical pesticides. Another general conclusion was that the effects of climate change will tend

to be different for different pathosystems in different locations, so that generalization is a

challenge.

The direct effects of climate change on individual plants and plant communities may occur

in the absence of pathogens, but may also bring about changes in plants that will affect their

interactions with pathogens. Changes in plant architecture may affect microclimate and thus risks

of infection. In general, increased plant density will tend to increase leaf surface wetness and leaf

surface wetness duration, and so make infection by foliar pathogens more likely. Elevated CO2

levels tend to result in changed plant structure. At multiple scales, plant organs may increase in

size: Increased leaf area, increased leaf thickness, higher numbers of leaves, higher total leaf area

per plant, and stems and branches with greater diameter have been observed under elevated

CO2. Enhanced photosynthesis, increased water use efficiency, and reduced damage from ozone

are also reported under elevated CO2. Since many foliar pathogens benefit from denser plant

growth and the resulting humid microclimate, there is the potential for these changes in plant

architecture to increase infection rates.

Also, different populations of the same species may differ in both their genetic structure

and the extent to which climate change will push the species to its physiological limits. As a result

of climate change, the abundance of particular species may change rapidly, as species may lose

their ability to recover from other perturbations such as diseases, insect herbivores, and climatic

extremes within a background of climate changes. Novel plant communities may result with the

increased potential for new patterns of host-sharing by pathogens

The range of many pathogens is limited by climatic requirements for overwintering or

oversummering of the pathogen or vector. For example, higher winter temperatures of −6°C

versus −10°C increase survivorship of overwintering rust fungi (Puccinia graminis) and increase

subsequent disease on Festuca and Lolium. In the case of Phytophthora infestans, the

introduction of multiple mating types, allowing sexual reproduction, increases the ability of the

pathogen to overwinter. For pathogens subject to an Allee effect, or destabilizing density-

dependent reproduction at low population levels, release from overwintering restrictions may have

a much stronger effect than expected. Temperature requirements for infection differ among

pathogen species. For example, wheat rust fungi differ in their requirements from 2°–15°C for

stripe rust, 10°–30°C for leaf rust, and 15°–35°C for stem rust. In a review of the effect of climate

change on insect herbivory, Bale et al. make many points relevant to plant pathogens, whether

insect-vectored or not. They concluded that temperature was the dominant climate factor in terms

of direct effects through effects on overwintering and the potentially important combination of

photoperiod and temperature. In many cases, temperature increases are predicted to lead to the

geographic expansion of pathogen and vector distributions, bringing pathogens into contact with

more potential hosts and providing new opportunities for pathogen hybridization. Increased


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transportation and human movement may act synergistically with temperature changes

Temperature governs the rate of reproduction for many pathogens; for example, spore

germination of the rust fungus Puccinia substriata increases with increasing temperature over a

range of temperatures, and the root rot pathogen Monosporascus cannonballus reproduces more

quickly at higher temperatures. Under climate change, pathogens, like plants, may potentially be

unable to migrate or adapt as rapidly as environmental conditions change. But most pathogens will

have the advantage over plants because of their shorter generation times and, in many cases, the

ability to move readily through wind dispersal.

Disease management strategies may require adjustment under climate change. Strategies

such as delaying planting to avoid a pathogen may become less reliable. And one of the major

problems with applications of biological control for plant disease management in the field has been

the vulnerability of biocontrol agent populations to environmental variation. Simulation models are

based on theoretical relationships and can be used to predict outcomes under a range of

scenarios. Because climate change occurs slowly and variably, it is difficult to study its effects

directly. Temporal variability in climate can be used to draw inference about the potential effects of

climate change through the argument that temporary effects of a year with unusual climatic

features are likely to represent the effects of longer-term changes.environmental extremes.

Models of plant disease have now been developed to incorporate more sophisticated climate

predictions from General Circulation Models.

In the population level, the adaptive potential of plant and pathogen populations may prove

to be one of the most important predictors of the magnitude of climate change effects on plant

disease, since, for many species, populations will not be able to migrate quickly enough to keep

pace with climate change.

Needs for further research

Due to the complex interaction of climate impacts, combined with varying irrigation

techniques, regional factors, and differences in crops, the detailed impacts of these factors need to

be investigated further. Specific recommendations for further research include:

• Precision in climate change prediction with higher resolution on spatial and temporal scales;

• Linking of predictions with agricultural production systems to suggest suitable options for

sustaining agricultural production;

• Preparation of a database on climate change impacts on agriculture; and

• Development of models for pest /diseases population dynamics.

Conclusions

It is evident that the relationship between climate change and agriculture is still very much

a matter of concern with many uncertainties. Predicted changes in average values of global

climate variables (increased temperatures, altered precipitation patterns, increased concentrations

of atmospheric CO2) and changes in the frequency, duration, and degree of extremes (such as

frost, heat, drought, hail, storms, floods) will affect agricultural crops, agroecosystems, and


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agricultural productivity. Forecasts of regional climate changes are still not precise. Overall,

shortage of water will be the predominant factor affecting plant growth. As higher temperatures are

known to enhance plant development and especially the grain-filling duration of cereals, grain yield

losses are possible in a warmer climate. On the other hand, elevated atmospheric CO2

concentrations are known to stimulate photosynthesis and enhance growth and yield ("CO2

fertilization"); concomitantly, leaf transpiration is reduced, resulting in improved water use

efficiency. Elucidating the interactions between positive and negative effects of climate change is

of crucial importance for any prediction of future crop yields. The prediction of the response of

crops to climate on both seasonal and decadal timescales shows promise. The potential benefit of

increasingly accurate prediction is clear: for the season, the mobilization of resources; for the

adaptive measures to minimise the adverse impacts of climate change.

REFERENCES

1. Bale JS, Masters GJ, Hodkinson ID, Awmack C, Bezemer TM, et al. 2002. Herbivory in global climate change research: direct effects of rising temperature on insect herbivores. Glob. Change Biol. 8:1–16

2. Coakley SM, Scherm H, Chakraborty S. 1999. Climate change and plant disease management. Annu. Rev. Phytopathol. 37:399–426

3. FAO. 1995a. World Agriculture: Towards 2010, An FAO Study. N. Alexandratos (ed.). John Wiley, Chichester, UK, and FAO, Rome.

4. FAO, 1995b. FAOCLIM 1.2, Worldwide agroclimatic data. FAO Agrometeorology Working Paper Series No. 11. FAO, Rome.

5. K.A.Garrett, S.P.Dendy, E.E.Frank, M.N.Rouse, and S. E. Travers 2006. Climate Change Effects on Plant Disease: Genomes to Ecosystems. Annu. Rev. Phytopathol. 44: 489-509

6. Masson et al. 2005. Impact of barrier layer on winter-spring variability of the southeastern Arabian Sea. Geophysical Research Letters, VOL. 32, L07703, doi:10.1029/ 2004GL021980.

7. Intergovernmental Panel on Climate Change. (2007). Climate Change 2007: Mitigation - Contribution of Working Group IV to the fourth Assessment Report of the IPCC.

8. Kalra Naveen and Sharma K Subodh,2007. Report on Climate change impact on Agriculture in India. Indian Agricultural Research Institute, Delhi


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Impact of Agricultural Intensification on Carbon Sequestration and Soil Health

K.P. Raverkar

Department of Soil Science, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Globally agriculture is a dominant form of land management covering about 40 percent of

terrestrial surface (FAO 2009). The existence and quality of life of human beings depends upon

the agricultural ecosystems as they fulfill the prerequisites of sustenance and wellbeing of human

life by providing food, forage, bio-energy and pharmaceuticals. In recent years, agro ecosystems

are being recognized for their contribution to other types of ecosystem services viz., regulating and

cultural services to human communities besides fulfilling the provisioning services (MEA 2005).

Management practices in agro ecosystems dictates the various services provided which are

supported by the ecosystem processes such as:- pollination, biological pest control, maintenance

of soil structure and fertility, nutrient cycling and hydrological services (Fig. 1). The value of

provisionary, regulatory and cultural services fulfilled by agricultural ecosystems is enormous but

often is not recognized or underappreciated.

Fig. 1. Impacts of farm management and landscape management on the flow of ecosystem

services and disservices to and from agro-ecosystems (Power 2010)

Humans depend on both natural and managed ecosystems for various services including

provisionary and environmental. With the advent of human progress, various agricultural

technologies developed leading to intensification of agriculture to take care of the demand for food,

fibre and feed of ever escalating global population. Agricultural intensification is a set of patterns of

land-use change with the common feature of increased use of the same resources usually

because of a switch from intermittent to continuous cultivation of the same area of land for

enhanced economical production. In the initial era, extensification was adopted to produce the

food. However, only extensification i.e. conversion of natural ecosystem to agricultural ecosystem


- 54 -

was not able to cope up with the increasing demand to meet the challenge of supplying food to the

escalating population due to limited land. With the time, linearly the gradient developed from being

the shifting cultivation at one end and intensification at the extreme. Along the gradient of

increasing land-use intensification, substitution of manual labour by mechanization, organic inputs

and natural pest management by agrochemicals use is experienced. The management practices

employed while intensification affects soil health.

Soil health in agricultural systems

Soil carbon, soil health and sustainable agriculture are interlinked. Soil carbon is also

termed as a life as it supports the agents involved in continuum of various biogeochemical cycles.

Soil management is fundamental to all agricultural ecosystems; however, there is an evidence for

widespread degradation of agricultural soils in the form of erosion, loss of organic matter,

contamination, compaction, increased salinity etc.

Concept of soil health

The growers looking at the crop health, soil color, intensity of earthworms, visibility of plant

residue etc. judge the soil health. Scientifically it is judged either employing the reductionist or

integrated concept. Reductionist concept advocates an estimation of soil condition using a set of

independent indicators of specific soil properties while integrated concept assumes that the health

of a soil is more than simply the sum of the contributions from a set of specific components. It

recognizes change in emergent properties resulting from the interaction between different

processes and properties.

A healthy agricultural soil is one that is capable of supporting the production of food and

fiber, to a level and with a quality sufficient to meet human requirements together with continued

delivery of other ecosystem services that are essential for maintenance of the quality of life for

humans and the conservation of biodiversity (Kibblewhite et al., 2008). The soil provides the

various services to the community through:

Transformation of carbon through decomposition of plant residues including SOM

Essential ecosystem function

Driver of nutrient cycling

Supports detoxification and

Waste disposal service

C-sequestration: role in regulating emission of GHG e.g. CO2 and CH4

Cycling of nutrients: N, P, K including N2O emissions

Maintenance of structure and fabric of the soil

Soil aggregation

Particle transport

Formation of biostructures

Pore networks

Biological regulation of soil population


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The living system in soil comprising microflora, microfauna and macrofauna governs the

various services provided by the agricultural soils. The relationships between the activities of the

soil biological community and a range of ecosystem goods and services does exist (Fig 2).

Fig.2. Relationships between the activities of the soil biological community and a range of

ecosystem goods and services that society might expect from agricultural soils

(Kibblewhite et al 2008)

Carbon Sequestration

In the terrestrial system, carbon is mainly held in vegetation and soil. Aquatic bodies like

oceans also stocks large volumes of carbon, as does the atmosphere. Soils contain about three

times more C (1500 Pg of C to 1 m and 2500 Pg of C to 2 m depth) than vegetation (650 Pg of C)

and twice as much as that present in the atmosphere (750 Pg of C; USEPA, 1995). Additionally,

fossil fuels e.g., coal, petroleum, and natural gas contain large amounts of carbon that are

released upon combustion.

Fixed carbon is a life of soil and also governs the capacity to provide the nutrients to plants.

All biogeochemical cycles revolve and dictated by the element carbon. Carbon supports the

existence and flourishes the life on the earth. All ecosystems both store and emit carbon back to

the atmosphere at lesser or greater extent as they continuously recycle carbon by photosynthesis

and respiration.

Soil is the biggest reservoir of carbon. Soils can be a source or sink for atmospheric CO2

depending upon the land use and management practices. The conversion of natural habitats to

cropland and pasture, and unsustainable land practices such as excessive tillage frees carbon

from organic matter, releasing it to the atmosphere as CO2 and thus soil acting as a source

whereas the photosynthetic activity, through which the plants convert CO2 into organic forms of

carbon such as sugars, starch and cellulose; as a sink. The soil organic carbon (SOC) pool to 1m

depth ranges from 30 tons/ha in arid climates to 800 tons/ha in organic soils of temperate regions.


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The predominant range of SOC is 50-150 tons/ha. The conversion of natural habitats to

agricultural ecosystems has resulted in depletion of SOC pool by 60 and 75 per cent in soils of

temperate and tropics, respectively. The depletion of SOC pool generally takes place speedily

when the decomposition rates are higher than the rates of carbon added to soil. Severe loss of

SOC leads to deterioration of soil quality, biomass productivity and also affects the water quality.

An overall impact of depletion of SOC levels may be exacerbated by projected global warming

(Lal, 2004). Organic matter plays important role in modulating functions:-

Provision of surface charges (CEC)

Influencing hydrological properties etc.

Soil organic carbon (SOC) pool represents a dynamic equilibrium of gains and losses.

Various practices either contributes or depletes the SOC. Conversion of natural to agricultural

ecosystems causes depletion of SOC pool. Depletion is more in arid/ tropics to the tune of 75

percent or more as compared to temperate regions (60%). The depletion is exacerbated when the

output of C exceeds inputs under the situation of severe soil degradation. Some soils have lost as

much as 20-80 t C/ha, mostly emitted in to the atmosphere.

Soil: Reservoir of C

The carbon from the atmospheric CO2 can be transferred to the long lived stable form in

the soil and plants through the process of sequestration. The process of carbon sequestration

results in the increased SOC and soil inorganic carbon stocks through the judicious

implementation of the land use and friendly/ good management practices. Carbon is referred to be

sequestered if it is converted into a stable form i.e. wood or soil organic carbon. Soils acts as

source as well as sink for atmospheric CO2. The conversion of natural habitat to crop land and/ or

unsustainable land practices lead to source while photosynthesis is the only viable way to trap CO2

from atmosphere and bank in soil.

Soil organic matter comprises of mainly unhumified substances and mummified remains of

plant and animal tissues. Soil being a graveyard for all types of organisms, it may contain all the

biochemical compounds synthesized by the flora, fauna, animals and plants. The soil organic

matter mainly comprises living organisms, fresh residues, and well decomposed residues. These

three parts of soil organic matter can be described as the living, the dead and the very dead.

The dead constituent of the soil organic matter is also referred as the labile pool/ carbon fraction

as it is easily decomposable, susceptible to microbial breakdown and easily oxidizable while the

very dead is resistant to further degradation, microbial breakdown and oxidization. The turnover

time of different fractions of the soil organic matter ranges between 0.1 to 1000 years (Carter,

2002). Therefore, the carbon sequestration in soil depends upon the amount of the carbon put

away in different fractions. More the amount stabilized in the component having the longer

turnover time the more carbon sequestration for longer period.

Loss of SOC

In Asia, India has the lowest average concentration of SOC in agricultural soils (Kyuma,


- 57 -

1988). The alluvial soils of Indo-Gangetic Plains are inherently fertile and high in K, however

intensive cultivation of rice-wheat; rice-maize and taking away of almost all crop residues lead to

continuous decline in SOC levels (Nambiar, 1994). The Long Term Fertilizer Experiments in India

has indicated that the intensive cropping and imbalance fertilizer use especially fertilizer N alone

resulted in declined SOC concentration irrespective of cropping system and type of the soil

(Swarup, 1998). Accelerated erosion due to wind and water is also a major cause of terrestrial

carbon loss. In India, the extent of soil degradation due to various factors is as below:-

Desertification 68.1 Mha

Water erosion 32.8 Mha

Wind erosion 10.8 Mha

Water logging 08.5 Mha

Salinization 07.0Mha

The emission of C from fossil fuels has increased dramatically since 1970 onwards due to

industrialization, intensive agricultural practices etc. leading to deterioration of soil quality and

enchanced CO2 in atmosphere.

Importance of C sequestration in Soil

Carbon sequestration has a great role in maintenance/ building of soil quality vis-a-vis

sustainability. The importance of carbon sequestration at local/ individual, national and global

scale is depicted in Table 1.

Table 1. Importance of carbon sequestration in soil

Local/ farmer scale National scale Global scale

Improved food security Improved food security Improvements in global climate change

Improved resource base for future generation

Better agricultural sustainability

Reduced CO2 concentration in atmosphere

Reduction in soil degradation and improved soil fertility

Improvement of environmental issues (air and water quality)

Biodiversity build up

Improved crop, timber and livestock yield

Economic returns Economic returns

Improved soil and food quality Social security Social security

Economic returns

Social security

Agricultural intensification: Boon or Bane for C sequestration

With the advent of agriculture, various modern practices and technologies made the

agriculture intensive. Agricultural intensification has been recognized as a source of considerable

emissions with concomitant opportunities for mitigation. However, investment in agricultural

research is rarely considered as mitigation strategy. Burney et al (2010) has analyzed the net

effect of GHG emissions of historical agricultural intensification between 1961-2005. The gist of his

findings is given below:


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Worlds population increased by 111% (3.08 to 6.51 billion)

Crop production rose by 162% (1.8 to 4.8 billion tons)

Agril. production has increased through both extensification and intensification

Gains observed since 1961: largely intensive

Global crop land grew by 27% (960 to 1,208 Mha)

Total crop yield increased by 135% (1.84 to 3.96t/ha) weighted mean across crop

groups

Dramatic increases in cereals and oil seeds were experienced because of:-

Adoption of high yielding varieties

Increased use of pesticides and fertilizers

Improved access to irrigation and mechanization

Direct GHG emissions through agricultural production (2005)

• C emission through Agricultural production: 1.4-1.7 Gt (10-12% of total anthropogenic GHG

emission)

• C emission due land use change: 1.5 Gt

• Agricultural emissions outside land use change

– N2O released from soil related to application of N-fertilizers: 38%

– CH4 : Livestock enteric fermentation and CH4 and N2O from manure management:

38%

– CH4 from rice cultivation: 11%

– CH4 and N2O from burning savannah, forest and agricultural residues: 13%

Indirect GHG emissions through agricultural production (2005)

• Emission in the industrial and energy sectors through production of fertilizers and

pesticides

• Production and operation of farm machinery and

• On farm energy use

Mitigation potential in each area contributing to GHG emission

Each area of agricultural intensification has the mitigation potential to control GHG emission. For

example:-

• Modified rice drainage and straw incorporation practices could reduce global CH4 emission

from rice cultivation: up to 30%

• Precision agriculture and nutrient budgeting facilitates efficient use of fertilizers: reduce

emission associated with excess application

• conservation tillage and potential for sequestration of soil OC in agricultural system: build

fertility and improve yields in degraded soils

• Each of these strategies play role in comprehensive set of crop management guidelines

aimed at simultaneous mitigating agricultural GHG emissions and meeting increased future


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food.

Climatic implications of agricultural intensification

• Burney et al. (2010) calculated agricultural GHG emissions for 1961-2005 as well as two

hypothetical “Alternate World” (AW) scenarios

• In both AW scenarios the growing food needs met by extensification rather than yield

increase (intensification)

• In each case, N2O from agricultural soils, CH4 from rice cultivation, C released from both

biomass and soil by conversion of forest, shrub and grassland to cropland; and N2O, CH4

and CO2 from production and use of N, P and potash fertilizers was considered.

Assumptions

• Alternate World Scenario 1 (AW1)

In this the assumptions were that:

– Population, the global economy and socio-politics evolved exactly as in the Real

World (RW) but agricultural technology and farm practices remained as in 1961

– same crop yield and fertilizer application rates as in 1961 (extensification)

• This hypothetical scenario addresses the question: What it would cost in terms of GHG

impact to replicate current global standard of living in the absence of investment in yield

improvements.

Burney et al (2010) found under such situations as listed above that:

• Additional 1761 Mha of crop land would have needed to achieve same production levels

since 1961 holding yields and fertilizer intensities constant. OR 1514 Mha more cropland

than in RW.

• Potential arable land available in world: 2945 Mha.

• Fertilizer use increase from 31Mt of nutrient to 88Mt of nutrient with constant mean annual

intensity of 32 kg/ha.

• In RW total fertilizer use increased to 136 Kg/ha OR 165 Mt.

• Yield gains in agriculture since 1961 avoided emissions of 161GtC or 3.6 Gt C/year

• Alternate World Scenario 2 (AW2)

In another hypothetical situation it was assumed that:

– A world increased agricultural production is only enough to maintain 1961 standard

of living (in terms of per capita production) through 2005, again through

extensifiction instead of intensification

Under the AW2 situation it was noted that:

Impacts are roughly half than AW1 scenario.

Additional 1111 Mha of cropland would have been needed to maintain per capita

production at 1961 levels while yield and fertilizer intensities holding constant. OR 864 Mha

more cropland than in RW


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Fertilizer use rises from 31Mt of nutrient to 67Mt of nutrient representing same constant

1961 intensity of 32 kg/ha .

Without accounting for any increases in global living standards, yield gains in agriculture

since 1961 have avoided emission of 86.5 Gt C OR an average of 1.9 Gt C/year.

These studies demonstrated that the importance of intensification over extensification to

mitigate the climate change and improve the carbon sequestered in soil vis-a-vis soil

quality. They further suggested that the climatic impacts of historical agricultural

intensification were preferable over a system with lower input with extensification of

cropland to fulfill the demand for food. Continuing improvement of crop yields through

intensification is paramount for agriculture’s future contribution to mitigate climate change.

Further, it has been emphasized that intensification must be coupled with conservation and

development efforts.

Strategies for C sequestration in soil

To mitigate the climate change and global warming the CO2 concentrations in

atmosphere needs to be combated to a level to sustain life on earth and keep

environment clean.

Efficient land use

Diversified cropping

Conservation/reduced/no tillage

Efficient nutrient management

Administered grazing

Aforestation/ agro-forestry

Erosion control

Use of cover crops

Mulching

Rehabilitation of degraded soils etc.

Biostrategies

Afforestation

Ecosystem restoration

Energy plantation

Raising of deep rooted plantation/crops

Growing species with higher content of cellulose and other recalcitrant material

Organic Residue management

Efficient management (mulching/ incorporation) must for enhanced SOC

o Improves infiltration capacity of soil

o Reduce run-off rate

o Reduce soil loss through detachment and transportation

440 Tg plant residue produced in India out of which about 90% is a cereal residue.


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However, it is used as fodder, fuel, construction etc. It is advisable that for the

maintenance/ improvement of soil quality residue should be spared for

incorporation in soil.

Different organic amendments over a long period in various cropping systems

improved the organic carbon status that is a life of soil (Table 2).

Table 2. Impact of different organic amendments on SOC under different cropping sequences

Cropping system Organic amendments Organic carbon (%)

Maize-wheat (25 yrs) Control FYM

0.51 2.49

Cotton-sorghum (45 yrs) Control FYM

0.56 1.14

Ragi-cowpea-maize (3 yrs) Control FYM

0.30 0.64

Rice-rice (10 yrs) Control 50% from inorganic + 50% through green manuring (Sesbania aculeate)

0.43 0.90

Rice -wheat (3 yrs) Control FYM

0.44 0.54

Rice -wheat (7 yrs) Fallow Green Manuring (Sesbania aculeate)

0.23 0.37

Source: Swarup et al., (1999)

Epilogue

o Each dollar investment in agricultural yields resulted in 68 fewer kg C emissions relative to

1961 technology avoiding 3.6GtC per year.

o Yield improvements should be prominent among efforts to reduce future GHG emissions.

o Crop and soil management techniques should be adopted accordingly to enhance potential

of Carbon sequestration

o Good agronomic practices should be followed so that Carbon sequestration can be

increased e.g. reduced tillage.

o To make the farmer aware of the economical benefits of sequestering Carbon.

o Relevant policy consideration that encourage adaptation of various useful practices for

increasing C sequestration.

o All the above stated statements are achievable provided at scientific researches and

policies are implemented with a political will.

o Agril. Intensification should be recognized as GHG emission mitigation strategy at par with

the other strategies.

o Enhanced fund allocation for yield improvements

o Efforts to put away fraction in SOM with high stability and longer turnover time.


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REFERENCES

1. Carter, M.R. (2002). Soil quality for sustainable land management: Organic matter and aggregation interactions that maintain soil functions. Agrnomy Journal 94:38-47.

2. FAO (2009). Food and agriculture organization of United nations statistical database. Available at http://faostat.fao.org/.

3. Kibblewhite, M.G., Ritz, K and Swift, M.J. 2008. Soil health in agricultural systems. Phi. Trans. R. Soc. B. 363: 685-701.

4. Kyuma, K. (1988). Paddy soils of Japan in comparison with those in Tropical Asia. In Proceedings of First International symposium on Paddy Soil Fertility held at Chiagmai, Thailand, December 6-13, 1988. p. 5-19.

5. Lal, R. (2004). Soil carbon sequestration impacts on global climate change and food security. Science 304: 1623-1627.

6. Nambiar, K.K.M. (1994). Soil fertility and crop productivity under long term fertilizer use in India. Indian Council of Agricultural Research, New Delhi.

7. Power, A.G. 2010. Ecosystem services and agriculture: tradeoffs and synergies. Phi. Trans. R. Soc. B. 365:2959-2971.

8. Swarup A. (1998). Emerging soil fertility management issues for sustainable crop productivity in irrigated systems. In Proceedings of a National Workshop on Long-Term Soil Fertility management Integrated Plant Nutrient Supply (Swarup, A., Damodar Reddy, D. and Prasad, R.N.; Eds.). Pp. 54-68.

9. USEPA (1995). Inventory of US greenhouse gas emissions and sinks, 1990–1994. Washington DC.


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Seed Health Testing: Retrospective and Perspectives

Karuna Vishunavat Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

For food sufficiency, India underwent introduction of new crops or high yielding varieties of

indigenous planting material, particularly the seed. Of course, it helped India to sustain its food

security via green revolution but at the same time there had been challenges of introduction of

many seed-borne plant pathogens which later established or posed problems time to time for

successful crop production.

Pathogens thus, introduced remained confined to some regions initially, but later spread all

over the country. The diseases which used to be of minor importance became the major diseases

in the regions where pathogen established and disseminated.

There have been the evidences that the infected or contaminated seeds at an early stage

can lead to proliferation of microorganisms through out crop production leading to substantial crop

losses an at times to epidemic proportion

Thus, the seed which is the key input for all crop cultivation has the potential for

transboundary spread of plant diseases and serves as primary source of inoculum for disease

epidemics.Seeds are both the vectors and victims of diseases.

Seed borne diseases vs. Crop production

It is estimated that 30% diseases are of seed borne nature and can be managed through

disease-free seeds. The losses due to seed-borne diseases in developing countries are estimated

to be 60-80% higher than in industrialized countries. Conservatively estimated, seed-borne

diseases cause losses in the order of 50 million ton of food annually.

poor seed healthLeads to poor seed germination to various degrees ,give rise to pre- and post

emergence seedling mortality and progressive disease development in the field and thereby

reduces the yield and quality of the crop,contaminate previously disease-free areas,Spread of the

diseases across national or international boundaries,reduce shelf life of the seed and affects food

safety /mycotoxins /nutritional value

Significance of Seed-borne Pathogens

In worst-case scenario, seed-borne organisms can be disastrous and even life

threatening.

Evidences are there that the consumption of molded grains of wheat, millet, and barley with

Fusarium killed thousands of human beings in the USSR in 1913 after World War II due to toxin

production by the fungus.

Effect of Seed borne diseases in crop production

The major component of losses due to seed borne pathogens are : Quality loss,Cost of

planting restriction,Loss of seed export ,Additional cost of transportation and yield losses.


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Significance of seed-borne pathogens

Few examples which exemplify the significance of seed borne pathogens and their effect

on seed production are mentioned :Blast of rice (Pyricularia oryzae) had been so much so

devastating and was held responsible for famine in Japan in 1930.Yield losses had gone upto

100% due to loose smut in wheat ( Ustilago segatum var. tritici) in Georgia .Brown spot of rice (

Drechslera oryzae) a devastating disease and was held partly responsible for Bengal famine in

1942-43 in India. The fungus is major components of the dirty panicle syndrome of rice. Another

menace to wheat is glume blotch (Septoria nodurum) , known to be present serious in many

European countries , USA and India causing substantial losses in wheat productivity .Losses due

to Karnal bunt of wheat in North western Mexico have been estimated to an average of $7.02

millions/year.Brown spot of rice ( Drechslera oryzae) a devastating disease and was held partly

responsible for Bengal famine in 1942-43 in India. The fungus is major components of the dirty

panicle syndrome of rice. Another menace to wheat is glume blotch (Septoria nodurum) , known

to be present serious in many European countries , USA and India causing substantial losses in

wheat productivity.Losses due to Karnal bunt of wheat in North western Mexico have been

estimated to an average of $7.02 millions/year. Menace to chickpea by Ascochyta blight (

Ascochyta rabiei) in the year 1982-1984 in India and Pakistan. The diseases occurred in serious

proportions and caused substantial yield losses.In severely infected fields no seed setting could

be observed.

Sunflower Downy Mildew unknown in India till 1984, caused by Plasmopara helianthi is

considered to be of North American origin.In 1985, it has been reported to occur in a serious form

in Maharashtra.the disease distributed rapidly by seed trade.

A few examples are bacterial blight in rice( Xanthomonas oryzae),common bacterial

blight of bean ( X.phaseoli ) ,black rot of crucifers ( X.campestris pv. campestris).Bacterial blight of

paddy rice was 1st observed in Mahrashtra (formerly Bombay) State in 1951, when it was reported

in Kolaba District but it was not until 1963 that an outbreak of disease occurred accounting for total

crop failure as happened in Punjab, Haryana and Western Uttar Pradesh States of India in 1979

and 1980. In India, the disease can account for more than 20% rice crop loss, periodically.

Most Seed borne viruses are asymptomatic and transmit efficiently through infected seed

and further disseminated by a number of vectors . Although the losses are attributed to the

environmental conditions and the prevalence of the vector population of that area.For example,

one infected plant will produce 100% infected seed (soybean mosaic virus) such seed will be

viable and germinate well, but the resulting plants will be infected and yields will be significantly

reduced.

All these examples exemplify the significance of seed borne pathogens and their effect on

seed production.

Resurgence of diseases

Spot blotch or Helminthosporium Leaf Blight (HLB) caused by Bipolaris sorokiniana was


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observed way back in 1971 in Canada . The losses attributed due to the diseases have been

equivalent to $42millions in 1971.

The resurgence of the disease was observed in serious proportion during 2008-2009 in

different districts of Sindh and Punjab. The yield reduced from 6.0 tons/ha to a mere yield of 1.6 to

2.2 tons/ha from their potential lands.

With the change in cropping system and the excessive use of chemical pesticides, there is

resurgence of diseases examples are necrosis in sunflower and ground nut that can not be

neglected for crop production and food security .Apart from the threat posed by resurgence, a

large number of diseases are endemic and continue to cause losses in given area example Karnal

Bunt of wheat.

New Challenges

With the new dimensions in Indian agriculture, which is not only confined to the varietal

developments by conventional breeding for crop improvement in yield and quality traits but for

value addition and for food biosecurity, new tools are being used for crop improvement,

(transgenics, or BT crops) by way of biotechnology.

This may change the scenario of the pathogens and plant diseases in agriculture.

Thus, a threat form exotic destructive pests is foremost importance in the era of liberalized

import under WTO. However, the changing conditions the indigenous pests already existing but

having the lower damage level in India are changing their habit and gaining more importance over

the years.

Seed-borne diseases and Seed health: perspective

As a consequence of increased product liability and competitive pressure with in the seed

industry, seed health has also become an important quality trait in market place.

The demand and pressure for seed health testing is however increasing to deliver healthy

seed to farmers and seed producers.SPS (Sanitary and Phytosanitary) issues in WTO are

pressurizing the developing countries to give special attention to seed health testing and to respect

International Phytosanitary Regulations (IPR) issues.

Seed health management needs to be focused on: Estimation of losses attributed to seed-

borne inoculums,Predictive relationships between seed-borne inoculum and disease

incidence,Developing reliable, effective, cheap and rapid detection methods,An understanding of

pathogen tolerance in a seed lot before a technique is an acceptable clinical seed health

test,Establishment of seed health certification schemes,Decisive proper seed processing and seed

treatment.

Advances in Seed Health Testing

The first International Rules for Seed health Testing was published by ISTA in 1928. This

document contained a special section on Sanitary Condition in which special attention was

recommended for Claviceps purpurea, Fusarium, Tilletia, and Ustilago hordei on cereals;

Ascochyta pisi on peas, Colletotrichum lindemuthanium on beans; and Botrytis, Colletotrichum


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linicola, and Aureobasidum lini on flax.

The demand for better seed quality, greater sensitivity and shorter turnaround times for

seed testing is forcing seed health testing laboratories to incorporate new technologies which will

provide the user with a significant level of reliability, sensitivity, and reproducibility of the test.

In last 35 years, several seed health testing procedures, published by International Seed

testing Association (ISTA) are now obsolete and need to be revised or revalidated by newer

technology due to fast pace of technological development

Seed Testing Methodologies:

Many conventional seed health testing methods have been developed such as: agar

plating, blotter test, seedling bioassay, microscopic observation, Direct isolation of pathogens,

growing on test .However, they are multi-stage, and are often slow, cumbersome time consuming,

labour-intensive and subjective.

Recent advances in Seed health testing

Serological Methods

These methods are generally simple to perform, rapid and accurate when used, generally

to detect a number of bacterial and viral pathogens even if present in low level. These methods

are being applied for many seed borne pathogens successfully, for example, indexing seed for

lettuce mosaic virus was started as grow-out assay on several thousand seedlings (30,000).Later

the test was changed to indicator host plant Chenopodium quinoa test . Since 1983, ELISA

(enzyme-linked immunosorbent assay), has been used which not only proved to be more efficient

but very sensitive in detecting low levels of infections that could potentially threaten lettuce

production.

The lack of sensitivity and ambiguity in results and inability to detect all strains of the pathogen

sometimes limits their use.

Indirect Immuno-fluorescence Colony Staining Method

This method is used for detection of seed-borne bacterial pathogens, especially suitable

for seed companies, and quarantine stations which have no facilities for conjugation of primary

antiserum.The assay is easy to perform and quick to be assessed. Choosing the right secondary

conjugate is however, necessary to get best results in the assay.

Nucleic acid based detection methods

Highly sensitive BIO-PCR methods have been developed for several bacterial pathogens

from seeds, including Pseudomonas syringae pv. phaseolicola, Acidovorax avenae ssp. avenae

Xanthomonas oryzae pv. oryzae and X. campestris pv.campestris.

Molecular Methods

Certain laboratories are testing the D-Genos ready-to-use kits to detect certain seed borne

bacterial pathogens (Pseudomonas savastanoi pv. phaseolicola and Xanthomonas axonopodis

pv. phaseoli on bean seeds) . The data obtained are conclusive enough to allow the use of D-

Genos kits for routine testing as an alternative to standard procedures.


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Molecular methods for Seed-borne Fungal Pathogens

Populations of two fungal pathogens of rice - Bipolaris oryzae (Cochliobolus miyabeanus),(

brown spot) and Saracladium oryzae, (sheath rot) - were used as model pathosystems.Methods

were developed to characterise these organisms using polymerase chain reaction (PCR) with both

random amplified polymorphic DNA (RAPD) and simple-sequence repeat SSR oligonucleotides as

primers

Challenges for seed health testing in Seed Industry Seed health testing require greater

emphasis by plant protection authorities on seed health testing. Reliability of tests is

questioned.there should be Harmony in testing procedures and the protocols must be suitable to

test the seed health .

Constraints in seed health testing on routine basis

To date there has been no systematic attempt to evaluate the large number of test

procedures for their appropriateness, whether in terms of cost, ease of use, but even more

importantly their scientific validity.


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Communication Skills in Teaching

Birendra Kumar & S.K.kashyap Department of Agril. Communication ,GBPUAT, Pantnagar- 263 145 (Uttarakhand)

Teaching is a noble profession. It is mission for many people. History is full of prophets and

saints who have embraced the role of teacher to influence others. People take up teaching without

mental preparation or about the gravity of the role. Role of teacher is not only to pass notes or

facts but to stimulate minds to think, analyze and learn.

Teaching is not filling the bucket but lighting the lamp

Students are not empty boxes like buckets. They have experiences, own perception and

ways of learning. Thus, a teacher has to know to approach learners at their and with their

cooperation.

Hundreds of researches have revealed that more effective teachers

Have enthusiasm for teaching; They love to go to class and meet students. They are

emotionally charged and feel happy after teaching.The students also feel pleasure in

attending such classes.

Are interested in learners & subject: : They pay attention to students’ problems, interact

inside and outside of class. They like subject and in turn create an interest for it in students

Have expertise: They have mastery over the content and have comprehensive

understanding of theory and practice

Give praise & maintain positive environment:: They are postive minded and appreciate

good behaviour of students.They always try to create situations in which students perform

well

Are professional in conduct & appearance: They take care of their personality, work and

time. Students fell inspired to meet them and learn from they words and act

Variability: They use variety of methods and aids to create interest and clarify the subject

matter.

Fairness/quality of exams: They are not only good teachers but good in evaluating

learning. Their examinations are quite balanced in content and testing abilities. They are

fair in assessment.

Preparation: He plans systematically and manages time efficiently. He is up to date about

latest in the subject and resources. Democratic: He allows students to actively participate

in class room activities. He may even delegate some roles to them.

Effective communication skills: He has command over language. He listens to students

and tries to encourage discussion

Teaching is not covering syllabus or passing information. Teachers are hired to influence

the minds of the learners. It is indeed quite challenging to motivate and enhance learning among

students. It is not enough for the teachers to know and understand the subject t. He has to find


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ways and means to make the learners know and understand what he has mastered already. This

is quite challenging and calls for more than subject matter knowledge. An effective teacher must

master the craft of communication. It is learners who have tol learn at the end of teaching? How

can they learn it during the given time? What approach should I select to achieve my outcome?

Learners are not empty pots. They have their own experiences and ideas. A teacher must begin

where the learner is and take them to the goal. Human mind is like parachute. It works best when

it opens. The teacher must do s something to open it. Thus, a teacher must learn a number of

skills as described below:

1. Entry behaviour

All the verbal and non-verbal commutation behaviour of teachers communicates something

to the students. Teachers must watch out their entry in the classroom. Do you enter carelessly

looking at walls, notes and blackboards? Do you consciously smile, look at the students and make

a few positive remarks. Be conscious and do not forget to look at your clients and greet them

enthusiastically. This builds positive atmosphere.

2. Opening remarks

Students come to your class from hostel or a last class with entirely different subject or an

hourly examination. Take time to draw their attention towards the lesson of your class. You may

ask one or more students to recapitulate the gist of the least class. How do you open your lecture?

Do you start the lesson of the day straight away by writing the topic? Start the class with relevant

questions. Giving personal experience and interesting cases relevant to the topic may catch

attention of the students. Alternately, students may be asked to recall the last lesson should be

clearly spelt out and even written on the board to act as road amp for the students. Let students

know exactly what is to be learnt, to prepare them for it.

Various techniques to begin:

Recall the last class

Stress importance of today’s lesson

Share a case/personal experience related with the lesson

Ask them to share something they have known or experienced about the topic

Discuss a current news item related with topic

It is believed that mostly student are not able to understand the major theme, if teacher has

not clearly specified the purpose. So let them know before hand what 4 or5 things they are going

to learn today, give them a little overview to crate interest. This will make students attentive and

alert about what is to be covered.

3. Designing Lesson

An old German maxim states

“All that is said not listened

All that is listened is not understood

All that is understood is not accepted


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All that is accepted is not done”

So there is a large gap between what they hear, understand and do. So the impact of

lecture is less in spite of the efforts People understand things better that are logically organized.

Logical organization demands organization from simple to complex, empirical to rational, contract

to abstract, know to unknown…………..

A well-designed lecture should consider the obstacles in communication from learners’

point of view. As a seasoned teacher, you may know their levels of understanding. Ability to

organize subject matter logically and in sequence is essential. A teacher must divide his topic into

three or four major parts. The parts should be organized in an easily understandable sequence.

Each part should be dealt with appropriate introduction, explanation and conclusion so that

learners can make sense of it.

Explanation

Explanation is an essential skill that a teacher must have to elaborate,exemplify and make

learning easy. Students may not understand terms or processdue to lack of pre-requisite

knowledge or awareness about the technical term or a process.A teacher mustask him/herself

these questions:.

Did you explain the new terms?

Did you make sure that students know the background information/

Are you sure that the language you are easy to understand for students.

If the answer to these questions is yes,then what strategy do you have to expand the content ?

Ability to explain requires explain a difficult term or phenomenon in many alternative ways. Use of

examples, evidences and visuals enhance understanding of new concepts.You amy relate with

something already known by students.

Use of audiovisual aids

Speaking alone is not enough. What you speak is lost in the air but what you write on the

board stays. Plan your board work in advance to put basic essential points on board. Planning

visual aids like charts, transparencies or power points beforehand helps to concentrate on

explanation. Besides teachers do not have pressure to remember everything. Take care to stand

aside and point out the exact on visual.

Use of verbal communication

Speak clearly and loud enough for everyone in the class to hear. Mind your pace of

speaking not too fast, not too slow. In fact, follow the same speed as in normal conservation.

Become aware if you are in the habit of repeating some words like I mean, you see, let me tell.

Avoid such vocal virus or else you will become a laughing.

Use of non-verbal communication

People perceive message mostly through non-verbal communication. Position yourself in

full view of the students. Look evenly at both sides; move a little towards students from time to

time. Use limited gestures. Use facial expressions to express emotion consistent with the dialogue.


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Student’s participation

Do students sit passively in your class? Are they taking notes all the time and listen

passively to what you speak? It is better to turn the table and their inputs. Sometimes, you may

ask the class to summarize what you have spoken in ten minutes. Encourage question answer

session at the end of the lecture to clarify doubts.

Use of questions

Questions are important stimulant for learners. Questions make them think different types

of questions can be asked for different purpose, as below:

To Check Awareness: Easy questions can be asked in between lecture to check deftness

of the students. Many students may volunteer to respond and thus, a positive atmosphere is

related. It breaks boredom of one way communication.

To Test Knowledge: Carefully worded questions may be raised to check understanding.

To Help In Application: Practical problems may be given to solve by using relevant theory.

To Develop Critical Thinking Ability: Question of high order may check analytical ability of

students.

Thus, questions may very form low level to high level depending upon the need. However,

it is also important to determine who should be asked.

Ask To The Class: Address the question in general to the whole class to see how many people

volumes to speak.

Ask To A Group: Question may be addressed to a group at the bask, front or side who may be

engaged in side-conversation or other diversion.

Ask A Person: Question may be addressed to a person to check his, her perform in particular

normally questions are addressed to the class.

Handling Students’ Questions

Students seldom raise questions but when they do it must be attended to properly.

Student’s questions are a prize to the teachers. They indicate that the student is attentive and

evolved. Teacher may return the question to the class to see of someone knows already. He may

rephrase the questions and give class for answer. In the end he may answer himself. Though it is

not necessary to respond himself.

Handling Students’ Response

Listening is key to responding the response of students should be listened carefully. He,

she should be complemented for the part of the response which is right. Student should be given

correct answer should be told with explanation. Thus, questioning handling response are important

skills to be used purposively.

Ask different types of questions to know the students’ progress. Sometimes you may ask

simple question to encourage response by many. You can raise the level of question to know the

dept of learning. Direct your question to all the students. Do not always ask a particular group only

to respond.


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Closure

Do not leave the class abruptly Like the opening, closure has a purpose. It must be planned

and linked to the overall lecture. Unfortunatly many teachers stop abruptly at the end of fifty

minutes or stretch till the nest teacher knocks. The actives to be performed at the close of the

lecture are as follow.

1. Pull out ideas from the lectures.

You any ask students to recall what has been presented today. Help them in recalling

important materials.

2. Help in application of the material.

It is desirable that students in higher education get to know the practical implications of the

materials covered in the class. Problem related with the topic may be discussed.

3. Achievement of adjectives.

You may intricate to the class the facts discussed in the light of the objectives.

4. Forward planning.

In order to prepare students for the next assignment to be completed. You may give a

preview of next class and ask students to bring some observations to get them ready.

Pull the key points and important explanations together and lead to meaningful

conclusion.

Ask them to recall key points

Tell them the appropriate reference to be consulted and question they think about.

You may ask them to come ready for the next lesson.

If possible tell them about the next clasd

Teaching should be planned and purposeful. A teacher must show positive orientation

towards students through verbal and non-verbal communication. Clearly of expression, simple

postures and controlled movement are helpful in conveying meaning.


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Climate Change in Social Perspective

R.P. Singh Directorate of Extension Education, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Our lives on this planet depend on nature’s provision of stability and resources. Current

rates of human-engendered environmental destruction threaten those resources and leave death

and misery in their wake. But we can avoid this. To do so, we must act in concert and with a sense

of urgency to make the structural and policy changes needed to maintain ecosystems and their

services, control water and air pollution, and reverse the trends leading to global warming. This

must be done if we are to achieve the level of environmental sustainability necessary to meet the

reduction of poverty, illiteracy, hunger, discrimination against women, unsafe drinking water, and

environmental degradation. By environmental sustainability we mean meeting current human

needs without undermining the capacity of the environment to provide for those needs over the

long term. Achieving environmental sustainability requires carefully balancing human development

activities while maintaining a stable environment that predictably and regularly provides resources

such as freshwater, food, clean air, wood, fisheries, and productive soils and that protects people

from floods, droughts, pest infestations, and disease.

Drivers for environmental change

In every region of the world, human actions have affected the natural environment,

resulting in rapidly diminishing the forest and increased consumption of scarce water and energy

resources, desertification, loss of biodiversity and increasing effect of global climate change. There

are two kinds of driver; direct and indirect drivers affect on climate change. Most significant direct

drivers of environmental degradation are-

Change in land cover; resulting from logging, urbanization, conversion to agriculture, road

construction and human habitation, among other factors, can impair the delivery of vital

ecosystem services, such as water retention and flood attenuation.

Pollution of air, soil and water by chemical and organic waste affects human health,

reduces agricultural production and damages ecosystems.

Invasive alien species are non native organisms that become established and spread in

new environments.

Over appropriation or inappropriate exploitation of natural resources can reduce

even the stock of renewable resources below sustainable levels.

Climate change may be the single greatest driver of environmental change on a broad

scale. It has such diverse effects as altered precipitation patterns, greater frequency of

extreme weather events, rising sea levels, increased ranges for some disease vectors and

changes in ecological systems.

Most influential indirect drivers which leads to environmental degradations of ecosystems

and pollution of our air, water and land are-


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Sociopolitical factors. Differences in social behaviour yield varying consumption and

production patterns and social change can produce unpredictable shifts in resource uses.

Demographic Change. Population growth, rural to urban migration and shift in house hold

economic status have important implications for the environment because they tend to

increase pressure on environment.

Economic factors. Economic growth intensifies resource consumption, drives land cover

change and generate waste. Extreme poverty can drive environmental degradation, in turn

enforcing poverty.

Scientific and technological change. Some new technologies can enable more effective

pollution abatement, whereas other technologies might drive overexploitation by increasing

resource extraction efficiency.

Market failures and distortions. Environmentally damaging subsidies can encourage

overproduction or overexploitation of resources such as fisheries and forest. Failure to

account for resource depletion may result in a misleading picture of economic conditions.

Environment and poverty

For too many of the worlds’ people, environmental degradation eclipses the hopes of

meeting even the most basic human needs. In developing countries, one person in five lakhs

access the safe water, 1.0 billion people live in dry lands and 1.2 billions live in less than Rs.50.0

per day. While consumption pattern of the rich drive overexploitation of the natural resources, poor

families, in their daily struggle for survival often lack the resources required to avoid degrading

their local environment. Their fragile resources, often poorly defined poverty rights, and limited

access to credit. With few alternative sources of income they rely extensively on the natural

resources and ecosystem services to supply such basic human needs as food, fuel and drinking

water. However, over extraction of resources disrupt the environment, causing many to loose

access to the ecosystem services on which their survival depends.

Reducing poverty and achieving environmental sustainability, then require charting a new

path for development between extremes of resource degradation on one hand and unsustainable

production and consumption on the other. Doing so will require a clear, ambitious set of objectives

and strategies with creative forward thinking leadership in each nation.

Environment and food security

Food security is integrally linked to environmental sustainability, as all food ultimately

derives from ecosystem services. More than two billion poor people rely directly on agriculture for

subsistence and commercial food production. The ecosystem services are critical for production

includes provision for freshwater for crop irrigation, maintenance of soil fertility through nutrient

cycle, provision of crop genetic diversity; crop pollinators, pest control and climate regulation.

Environmental degradation and biodiversity loss are urgent, fundamental problems that

threaten the achievement of goal like


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Where people lack access to modern agricultural technologies.

The condition of the local ecosystem determines agricultural productivity and food supply.

Thus sustainable management of terrestrial and marine ecosystem is a prerequisite to

global food security. Over the past century, 75 percent of crop diversity has been lost, leaving

crops and varieties vulnerable to emerging and spreading disease, pest and changing

environmental conditions. Land degradation continues as a result of inappropriate, intensive

agricultural techniques and land conversion related to agriculture extensification. Inappropriate

intensification causes salinization of irrigated areas, nutrient and pesticides leaching and pesticide

resistance while extensification destroys natural vegetation cover and leads to soil erosion and

loss of soil fertility, increased withdrawals of groundwater and surface water and increased

agrochemical loads (Wood, Sebastian and Scherr, 2000). These form of environmental

degradation decrease food availability, sometimes irreversibly, complicating efforts to fight hunger.

Environment and health

Environmental degradation adversely affects human health through exposure to bacteria,

parasites and disease vectors, chemical agents (such as heavy metals, pesticides in water, food,

air and soils), and physical and safety hazards (such as fire, radiation and natural disasters) (Bojo

and others 2001). Pollution and contamination of air and water are major sources of human illness.

Diarrhea strongly linked with unsafe water and inadequate sanitation, is the leading killer of

children under five. In most developing countries 90-95 percent of all sewage and 70 percent of

industrial waste are dumped untreated into surface water (UNFPA 2001). Acute and chronic

respiratory infections are related to ambient air conditions influenced by the incidence of wild fires,

vehicle pollution, and industrial discharge. Indoor air pollution from the use of biomass fuels in

poorly ventilated houses has been linked to 1.6 million deaths worldwide (Warwick and Doig

2004).

Many of the diseases, such as malaria, dengue and encephalitis are on the rise because of

human disruption of natural ecosystems. To the extent that the risk mechanisms are understood,

the potential for protecting or reducing the risk of certain diseases can be achieved through

incorporating sustainable conservation measures into development plans.

Demographic change

Demographic trends with key implications for the environment include population growth,

rural to urban migration and shift in household economic status. UN population division forecasts a

population increase of 2.6 billion people between 2003 and 2050, yielding a global population of

8.9 billion people, 86 percent of whom will live in developing countries (UNDESA Population

Division 2004). Fertility is highest in the poorest countries and among the poorest people in poor

and middle income societies. These countries have the highest levels of unmet needs for family

planning and reproductive health services; in concert with other health, education and gender

equality issues. At the same time, many developing countries are experiencing significant rural to

urban migration. By 2030, 60 percent of the worlds’ population is expected to live in urban areas.


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Urban population is increasing by 0.86 percent per year as rural populations post a similar decline

(UNDESA Population Division 2004).

These demographic shifts have key implications for resource use. Population growth

increases the demand for such essential goods and services as food, shelter and energy. It also

drives the production of greenhouse gases and airborne particulates, which cause human health

and environmental problems. Increased food demand can encourage agricultural intensification,

which can reduce pressure to convert natural habitat or extensification of agriculture. As

populations expand in countries that possess reservoirs of biodiversity, human pressures on

ecosystems and environment will grow. Indeed, population growth around biodiversity zones often

exceeds national aggregate growth rates (Cincotta and Engelman 2000). Rural to urban migration

is causing rapid expansion of cities with potentially adverse environmental consequences.

Economic change

Economic factors drive environmental change in at least six important ways. Economic

growth increases consumption and production, which intensifies resource exploitation; It drives

changes in land cover, its use and generates waste. Economic factors associated in rising

incomes are sometimes associated with investment in environmental improvement, cleaner

technologies and more robust environmental policies. Extreme poverty can be powerful driver of

environmental degradation and unsustainable exploitation results in the loss of important

environmental services, which can reinforce poverty. Fourth economic driver of environmental

change is environmentally damaging subsidies, such as those affecting the fisheries and forestry

sector. Other market failures include ownership problems associated with the tragedy of the

commons, externalities and distorting taxes. In addition, failure to account for resource depletion

may provide a misleading picture of economic conditions (Sachs and others 2004). Fifth,

increased international trade and financial flows shift consumption and production patterns as well

as patterns of resource use. And lastly exogenous shift in consumer preferences such as

emerging consumer demand for environmentally friendly goods and services may yield positive

environmental outcomes.

Sociopolitical factors

Sociopolitical factors influence the resource use patterns and affect countries’ willingness

and ability to invest in environmental protection. Differences in culture and social behaviour yield

varying consumption and production patterns and social change can produce unpredictable shifts

in resource use. Social conflict within countries causes and results form environmental

degradation. Environmental degradation can limit resource availability, strain social systems and

intensify latent social tensions. At the same time, countries in conflict, especially in the limiting

case of war, are unlikely to invest in environmental protection or other public goods.

Institutional gaps

Institutions develop shared norms and expectations for behaviour through such

arrangements as property rights and rule of law. Weak enforcement regimes fail to deter damaging


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forms of extraction such as poaching or illegal logging. Limited participation of key stakeholders in

planning and management of sustainable resource use reduces the legitimacy and effectiveness

of institutions, policy design and implementation.

Controlling the drivers of environmental change

The drivers of climate change are influenced by decision makers’ choices at all geographic

and political scales (Millennium Ecosystem Assessment 2004b, ch.7). Direct drivers of

environmental change are often endogenous to individual actions, while indirect drivers are usually

exogenous determinants of individual choices reflecting political, economic or social patterns at a

much larger scale. There are six key elements responsible for environmental change:

Forest

Freshwater resources and ecosystems

Agriculture production systems

Fisheries and marine ecosystems

Air and water pollution

Global climate change

The condition of these elements affects human health and economic wellbeing, biodiversity

conservation and environmental sustainability. These six elements provide the frame work for

environmental management.

Forest

Recent estimates suggest that forests provide more than 1.5 billion cubic meters of timber

and 1.8 billion meters of fuel (Wood or charcoals) every year (Matthews and others 2000). The

earths’ 3.4 billion hectares of forest directly contribute to the livelihoods of 90 percent of the worlds’

1.2 billion people living in extreme poverty and many others, in both developed and developing

countries by providing food, fuel, shelter, freshwater, fibers and genetic resources (Scherr and

others 2003). Extraction and processing of an array of forest resources- timber, medicine, fruits

and other nontimber forest products, forms the basis of many local economies. They also stabilize

natural ecosystems, storing carbon, controlling soil erosion and regulating movement of water

through the ecosystem. Clear cutting eliminates these services and can exacerbate the

consequences of natural disasters.

Fresh water resources and ecosystems

Freshwater resources are critical to human survival and environmental sustainability. They

provide the fundamental societal functions for human life support, food production and energy

production and a transport medium. Freshwater system support fisheries and other aquatic

biodiversity. Water uses of ecosystem functions and societal needs are interlinked because the

often depend on the same watershed. The integrated management of resources, which consider

the effects of one use upon others, is critical to coordinate supply to the multiplicity of end users.


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Agricultural production systems

Sustainable land based production is directly tied to the health and wellbeing of the world’s

populations, livelihoods and survival of world’s poorest people. Land based production system –

crops, orchard, plantation, graze land and freshwater aquaculture claims one third of the worlds’

terrestrial surface. Production systems are carved out of natural ecosystems where, a wide range

of services were provided. These include providing natural habitat for the worlds’ biodiversity,

including the inordinately large soil biota, the health of which is fundamental to maintaining soil

fertility. Land productivity depends on soil fertility and water availability. Good soil fertility plays an

important role in determining the current state of ecosystems and their future productivity.

There are three primary direct drivers of environmental change related to agriculture

production systems. Firstly land covers changes; agricultural extensification converts and

ultimately degrades natural habitat and marginal lands. Habitat degradation not only threatens

biodiversity, it also disrupts the soils’ natural regulatory functions resulting in soil erosion, reduced

water holding capacity and nutrient depletion, as well as desertification and other forms of soil

degradation. Secondly, over appropriation or inappropriate exploitation of natural resources;

inappropriate agricultural practices degrade soil, introduce pollutants, and contribute to salinization

or desertification. Misuse of fertilizers and modern agro techniques has contributed to chemical

degradation. In addition, inappropriate irrigation has produced depleted ground water resources.

Third driver is Climate change; it may dramatically alter rainfall patterns, leading to more frequent

droughts and flooding.

Demographic change is indirect driver. Population growth drives the need for more food

and productive employment. Land conversion is also driven by economic distortion. People living

in extreme poverty often lack sufficient resources to invest in maintenance of soil fertility. Poverty

can also drive people to strip the land without regard for long-term sustainability, even though

environmental degradation ultimately reinforces poverty. Finally, technology and information gaps;

such as inadequate trainings of crop production, perpetuate damaging, insufficient practices.

Fisheries and marine ecosystems

Ocean covers 70 percent of the planets’ surface and is by far the largest habitat for life on

earth. They supply billions of people with food and mineral resources. Marine biodiversity provides

critical global ecosystem services; climate control, carbon sequestration and oxygen generation. A

recent study that linked overfishing with climate change showed that sardines play an important

role in regulating upwelling ocean ecosystems by devouring large amounts of phytoplankton,

which would otherwise cause toxic gas plumes and dead zones upon decay on the ocean floor

(Bakun and weeks, 2004). Finally, coastal water provides cultural and environmental services,

frequently supporting tourism and recreation. As the interface between terrestrial and ocean

ecosystems, however, coastal systems are inappropriately affected by human activity.

Air and water pollution

Clean air and water are preconditions for human life and healthy ecosystems. The range of


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human activities that emit chemical, biological and particulate pollutants adversely affect human

health. Air and water pollution threaten marine and inland water resources, soils and forest. They

endanger biodiversity by destroying habitat, causing reproductive impairment and generating other

population level effects. There are two direct drivers of environmental change related to air and

water pollution; land cover change and over appropriation or in appropriate exploitation of natural

resources. And major indirect drivers are demographic change, economic factors, institutional

gaps and sociopolitical factors. Attempts to improve both air and water quality have been

frustrated by week regulatory and enforcement regimes.

Global climate change

Climate affects weather patterns and events, agricultural and marine productivity,

distribution and population health of species and energy consumption. In a complex feedback

system, the climate both drives and is driven by the interactions among components of

environment. Regional weather patterns are strongly influenced by vegetation cover, reflection of

solar radiation, air flow and the water cycle.

Evidence suggests that low lying small Iceland developing states and deltaic regions of

developing countries of South Asia and Indian Ocean could eventually be submerged. Crop

production could significantly decrease in Africa, Latin America and developing countries. Fresh

water could become scarcer in many areas that already face shortage (IPCC 2001).

The Solution

Achieving environmental sustainability requires dramatic changes in the ways societies and

citizens manage their biodiversity, wastes and byproducts of production and consumption process,

and consumption patterns. Improving environmental management also requires addressing the

direct and indirect drivers, the underlying causes of environmental problems. These structural

changes must complement and occur in parallel with the technical solutions. Few of these

solutions are:

1. Structural changes for environmental sustainability;

The following structural changes must be implemented in order for countries to effectively

integrate environmental concerns into all development plans and sector policies.

Train, recruit and retain environment experts.

Secure sufficient funding for environmental institutions.

Reform government institutions and improve interagency coordination

Improve governance and gender equality.

Account for the cost of environmental degradation in national accounts.

Introduce payment systems for ecosystem services and tax reform.

Phase out environment damaging subsidies.

Improve national and international regulatory framework.


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Establish mechanisms for science and technology advices.

Train decision makers for environmental management.

Provide public access to information.

Improve extension, training and services.

Science and technology must be at the center of any strategy for environmental

sustainability.

Universities and other institutions of higher learning should apply themselves

directly to sustainability goals.

2. Investing on environmental management;

To integrate environmental sustainability into national developmental strategies, we have to

take an ecosystem based approach to guide the planning of interventions in environmental

management. This management approach is a strategy for the integrated management for the

land, water and living resources that consider the connectivity of different landscape elements. To

fulfill these following recommendations may be considered-

Increase use of sustainable agriculture techniques to preserve natural assets;

protect and improve soils, use water sustainably, maintain agro diversity, mobilize

local knowledge and experiences, adopt prevention strategies to protect dry land,

mobilize information and technology, rationalize land use planning, minimize

fertilizer and pesticide use,

Increase real income of informal forest sector of atleast 200 percent by 2015.

Achieving this goal is requiring out reach to informal users, rationalization of

institutional and regulatory frameworks and incentives for conservation and

sustainable management.

Protection and restoration of ecologically viable representative areas of all major

forest, shrub land and pasture vegetation types and their biodiversity.

Slowing fresh water degradation requires reducing demand, especially in cropping

systems; controlling pollution; and protecting aquatic environments.

Increasing demand for marine products and services are resulting irreversible

losses, which requires managing fisheries at sustainable levels, rebuilding depleted

fish populations to healthy levels and establishing a network of representative, fully

protected reserves.

Action should be taken to reduce exposure to toxic chemicals and child mortality

caused by indoor air pollution and water born diseases.

Limiting the long term increase in global mean surface temperature to 2 degree

Celsius target requires investment in cost effective and environmentally sustainable

energy, climate friendly carbon and technology markets and adaptation measures.

Since environmental challenges act at local, national, regional and global scales,


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corresponding implementation mechanism must be developed. Only if all levels of government-

from local authorities to national governments, integrate the principle of environmentally

sustainable development into their policies and investment strategies can occur at the right scale.

This does not mean however, that civil society and private sector do not have critical role to play;

the contribution of both parties are critical for environmental sustainability to be achieved.

REFERENCES

1. Bakun, Andrew and Scarla J. Weeks. 2004.”Greenhouse gas buildup, Sardines, Submarine Eruptions and the Possibility of Abrupt Degradation of Intense Marine Upwelling Ecosystems” Ecology Letters 7 (11) : 1015-23.

2. Bojo, Jan, J. Bucknall, K. Hamilton, N. Kishor, C. Kraus and P. Pillai. 2001. “Environment” In The Poverty Reduction Strategy Sourcebook. Volume 1. Washington, D. C. Worldbank.

3. Cincotta, R. P. and R. Engelman. 2000. “Nature’s Place: Human Population and the Futures of Biological Diversity. Washington, D. C.: Population Action International. (www.populationaction.org).

4. IPCC (Intergovernmental Panel on Climate Change). 2001. Climate Change 2001: Synthesis Report. Geneva.

5. Matthews, Emily, Rechard Payne, Mark Rohweder and Siobhan Murray. 2000. Pilot Analysis of Global Ecosystems: Forest Ecosystems. Washington, D. C.: World Resources Institute.

6. Millennium Ecosystem Assessment.2004b. Scenarios Report.2nd

Review Draft. Published in 2005 by Island Press. Washington, D. C.

7. Sachs, J. D., J. McArthur, G. Schmidt- Traub, M. Kruk, C. Bahadur, M. Faye and G. McCord. 2004. “Ending Africa’s Poverty Trap.” Brookings papers on Economic Activity 2: 117-216.

8. Scherr, Sara J., Andy White and Devid Kaimowitz. 2003. A New Agenda for Forest Conservation and Poverty Alleviation: Making Markets work for low income producers. Forest Trends and the Center for International Forestry Research, Washington, D. C.

9. UNDESA (United Nations Department of Economic and Social Affairs) Population Division. 2004. Urban and Rural Areas 2003. New York.

10. UNFPA (United Nations Population Fund). 2001. The State of World Population 2001, Footnotes and Milestones: Population and Environmental Change. New York. (www.unfpa.org/swp/2001/english).

11. Warwick, Hugh and Alison Doig. 2004. Smoke: The Killer in the Kitchen: Indoor Air Pollution in Developing Countries. London: ITDG Publishing.

12. Wood, S., K. Sebastian and S. Scherr. 2000. Pilot Analysis of Global Ecosystems: Agroecosystems. Washington, D. C.: World Resource Institute and International food Policy Research Institute.

http://www.unfpa.org/swp/2001/english


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Resource Conservation Techniques in Plant Health and Disease Management: No Till or Reduced Till Cropping System

K.P. Singh

Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

No-till is one of the biggest breakthroughs in resource conservation agricultural technology.

It gives meaning to the term "sustainable agriculture", because it is practical, profitable, maintains

production targets, and protects soil and water quality on and off the farm. In the past 30 years,

innovative farmers have turned their attention to soil conservation.

The key benefit of no-till production is the ability to plant in a more timely way with less

investment in time and machinery costs. The other important benefit of no-till is that it allows

growers to establish a full no-till cropping system. The best chance of increasing soil organic

matter and improving soil structure over the long term occurs when all crops in the rotation are

planted using no-till practices.

No-till Defined

In a no-till crop production system:

The field is left virtually undisturbed from harvest to planting, except for nutrient injection

Fields are no longer ploughed, and plant residues remain on the soil to offer protection

from erosion

A narrow seedbed is prepared by the planter or drill during the planting operation, to allow

adequate seed and fertilizer placement

o alternatively, the row strip may be pre-tilled during a separate pass

Weed control is accomplished primarily with herbicides, but shallow inter-row cultivation

may still be used for emergency weed control.

of

Ind

ia


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Effect of no-till on soil properties

The effect of continuous no-till and conventional tillage in wheat on soil physico-chemical

properties was studied by Malik et al., 2004 at six long-term tillage sites under rice wheat cropping

system. These permanent sites had tropical arid brown soils. The bulk density (BD) of 0-7.5 cm

soil depth was greater in no till as compared to the conventional tillage in the first year (BD 0.12-

0.46 t/m3 higher) and third year (0.08-0.26 t/m3 higher). There was no detrimental effect of

increased bulk density on wheat germination and plant growth. Furthermore, the difference in BD

between the two tillage systems tended to diminish with time. The initial and basic water intake

rates were higher in conventional tillage (initial rate 6 – 48 mm/ha higher, basic rate 0.41 - 2.11

mm/ha higher) as compared to no-till. Slower water intake in no-till may be a reflection of the

destructive influence of puddling in the rice phase. The moisture retention, defined as the moisture

content in the 0-15 cm layer of soil at 7 days after first irrigation, was higher in no-till (up to 13.6%

higher) as compared to the conventional tillage system. Four years after the start of this multi-site

study, organic carbon (%) and available K in the 0-15 cm soil depth were higher in no-till (OC 0.09-

0.24% higher, and available K 8-36 kg/ha higher) as compared to conventional tillage. The soil pH,

electrical conductivity (1:2 soil: water) and available P were not affected by the tillage treatments.

The P contents (%) in wheat plants were higher in no-till (0.05 - 0.1 % higher) as compared to the

conventional tillage and this may be related to greater root growth under no-till. Savings in

irrigation water use are also an important feature of no-till systems.

The RW Consortium in collaboration with HAU undertook a detailed investigation of the

savings in irrigation water use under no till (Gupta, 2003). Fields under no-till and conventional

tillage systems were selected along an irrigation channel in Haryana to determine irrigation water

use. Studies showed that irrigation water used was 13- 33% lower in the fields under no-till, which

was attributed to lower water infiltration rate under no-till. The overall assessment of irrigation

water use by 4 villages in this irrigation scheme showed about 10% saving in water due to the

adoption of no-till. Average water use efficiency (kg grain produced/mm water used) was

estimated to be 18.3 kg/ha/mm in no-till fields as compared to 12 kg/ha/mm in the conventional

tillage fields, an increase of 35%. This improvement in water use efficiency is likely to be related to

avoidance of transient water-logging after the first irrigation which is a common feature of wheat

crops grown with conventional tillage in rice-wheat rotation. Savings in irrigation water can also

arise in some seasons when soil moisture content after rice harvest is adequate to sow wheat

without any pre-sowing irrigation.

Managing soils for no-till production

Well-drained, silt loam and clay soils are best suited to no-till production. Sandy soils have

been less successful, and poorly drained soils are not suited for no-till small grains. Growers with

sandy, coastal plain soils with more than 12 inches to clay often find that no-till cropping systems,

where no tillage occurs in any of the rotation crops, increases soil compaction. In such cases,

some deep tillage during one of the crop rotations may be required. On poorly drained soils, land


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leveling and/or the installation of tile drainage is necessary. One should examine soil classification

and drainage class for each field to determine how to manage soils for no-till production

Effect of tillage practice on soil microbes and diseases

Interest in no-tillage and conservation tillage systems is increasing due to scarcity and

increasing cost of fossil fuels, periodic food shortages, inclement weather conditions, and

concerns over soil erosion. Changing the tillage practice can lead to changes in the physical and

chemical properties of soil which in turn is likely to influence the occurrence of plant diseases. Key

factors in the occurrence of plant diseases include the survival and activity levels of pathogens,

host susceptibility, and the population of other soil microorganisms. Reduced tillage can favour

pathogens by lowering soil temperatures, increasing soil moisture, changing root growth, changing

nutrient uptake, and changing the population of plant pathogen vectors. The decomposition of rice

plant residues may release phytotoxins and stimulate toxin producing microorganisms, thereby

predisposing plants more to pathogen attack (Sturz et al., 1997). However, relatively high soil

microbial activity can lead to competition effects that may affect pathogen activity and survival and

thus reduce harmful pathogen inoculum pressures. This microbial antagonism in the root zone can

be beneficial for farmers by leading to the formation of disease suppressive soils. Thus, on the one

hand leaving plant debris on the surface or partially buried may allow pathogens to survive to the

next crop, but on the other, it may also make conditions more favourable for the biological control

of plant pathogens (Sumner et al., 1981).

Any major shift in farming practices, such as reducing or eliminating tillage, may inevitably

affect the micro-environment in which crops are grown. This in turn may alter the microbial

community in the soil. These communities include both plant pathogens and the microorganisms

that are natural antagonists of these pathogens. Many soil borne plant pathogens survive in the

soil via the previous years’ crop residues. However, no information is available on the effect of

zero tillage on the population dynamics of soil antagonists and the relationship between

populations of soil antagonists and soil-borne plant pathogens. (Varshney et al., 2002)

The rice-wheat cropping systems of the Indo-Gangetic plains face several productivity and

sustainability problems. These include late wheat sowing, low water and nutrient use efficiency,

groundwater depletion, water logging, poor water control, salinity and the build-up of weeds, pests

and diseases. The adoption of reduced and zero tillage cultivation of rice and wheat can address

some of these problems. It can improve the timeliness of sowing and help farmers cope with many

productivity and sustainability constraints (Harrington, 2000).

Many plant pathogens have been reported to increase to damaging levels under no-till

conditions and become constraints to efficient, profitable farming. Wheat pathogens have been

reported to be either favoured or controlled by zero tillage. The fungal pathogens Fusarium

graminearum, Pyrenophora tritici-repentis, Septoria tritici and Pythium spp. are reportedly favoured

by zero tillage whereas Bipolaris sorokiniana, Fusarium culmorum are reduced under no till

conditions (Bockus and Shroyer, 1998).


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Minimum-till or no-till cultivation may also lead to increased disease severity by pathogens

that survive better when infested crop debris remain on or near the soil surface (Garbeva et al.,

2004). For example, root rot and bare patch disease of wheat caused by R. solani AG8 are

favoured by reduced or no-till treatments in the U.S. Pacific Northwest and in Australia. Abawi &

Crosier (1992) demonstrated the influence of the reduced tillage practices on root rot severity and

yield of snap beans, as beans grown in rototilled and chisel-plowed plots had significantly higher

root rot severity than those grown in the conventionally plowed plots.

Under survey for build up of pests in zero tillage in selected farms, four sites in zero tillage

conditions along with conventional tillage plots under rice-wheat cropping system were monitored

for insect pests and diseases in wheat crop (Singh, 2004). In general, the incidence of yellow rust,

foliar blight and aphids was higher in zero tillage plots as compared to the conventional ones. In

rice crop also the observations indicated higher incidence of insect pests and diseases in zero

tillage plots as compared to the conventional tillage plots. Under evaluation of newly emerging

tillage practices FIRBS was found marginally superior to flat bed conventional tillage as it had

numerically less pest and disease incidence and higher yield.

Singh et al., (2002) indicated that the population of soil fungi was greater in conventional

than no-till fields in Haryana at the Crown Root Initiation (CRI) and dough stage of wheat, while no

consistent trend was observed in paddy. Fusarium species, Drechslera rostrata and Penicillium

species were predominant fungi in the rhizosphere of wheat and rice. The population of F.

moniliforme was greater in conventionally sown wheat fields than under no-till. F. moniliforme, F.

pallidoroseum, D. oryzae and D. rostrata were found to be pathogenic in paddy and Alternaria

triticina and Bipolaris sorokiniana on wheat. There was no significant difference between the tillage

systems in the incidence and severity of major diseases of rice-wheat sequence in Haryana.

Reduced tillage practices enhance species diversity and support larger microbial

populations in the upper layers of soil. Cultivation redistributes the microorganisms throughout the

upper and lower soil layers (Doran, 1980; Kennedy and Smith, 1995). In the wheat phase of

different cropping rotations, soil microbial biomass and bacterial diversity was greater in reduced

tillage systems (Lupwayi et al., 1998, 1999). Ergosterol content (an indicator of fungal biomass) is

greater with no tillage (Monreal et al., 2000). However, increases in microbial biomass may include

increases in both beneficial and pathogenic microorganisms but has a positive effects overall on

plant health and disease.

Soil organisms can protect plants from diseases and pests in several ways:

Healthy populations of microbes compete with pathogens for nutrients and can suppress

the severity of plant disease.

There are predatory organisms that will keep pest species such as nematodes and fungi in

check; protozoa engulf fungi and bacteria, while predatory nematodes eat root-feeding

nematodes.

Beneficial fungi provide a physical barrier to root-feeding pests by wrapping the roots in a


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network of threads (hyphae).

Other soil organisms secrete chemicals that ‘hide’ plant roots from their attackers.

Many agricultural practices can harm the organisms that live in the soil. There are

management actions that can be employed to minimize harmful practices:

Using rotations provide a more diverse food source and thus a more diverse group of soil

organisms. It can also break an existing pest/disease cycle.

Reducing tillage minimize habitat disturbance, maintain soil structure and increase organic

matter (food) for soil organisms and encourage a more diverse group of soil organisms.

Liming to keep the soil pH in a range favoured by plants benefit soil organisms.

Retaining stubble provides organic matter for soil organisms and encourages diversity. The

fungi that benefit from stubble left on the soil surface prey on nematodes. Incorporating

stubble increases its breakdown and reduce habitat for some pathogens.

The non-target effect of various agricultural chemicals is hard to determine, as there have

been very few studies on the organisms that live in the soil. Obviously fungi, including

beneficial ones like VAM, are susceptible to fungicides, and there is growing concern over

the effects of copper-based products on soil organisms such as earthworms.

REFERENCES

1. Bockus, W.W. and Shroyer, J.P. 1998. The impact of reduced tillage on soilborne plant pathogens. Ann. Rev. Phytopathol.36: 485- 500.

2. Doran, J.W. 1980. Soil microbial and biochemical changes associated with reduced tillage. Soil Sci. Soc. Am. J. 44:765–771.

3. Harrington, L. 2000. Synthesis of systems diagnosis: Is the sustainability of rice wheat cropping system threatened? - an epilogue. Journal of Crop Production. 3:2, 119-132.

4. Lupwayi, N.Z., Rice, W.A and Clayton, G.W. 1999. Soil microbial biomass and carbon dioxide flux under wheat as influenced by tillage and crop rotation. Can. J. Soil Sci. 79:273–280.

5. Monreal, M.A., Derksen D.A, Watson, P.R and Monreal, C.M. 2000. Effect of crop management practices on soil microbial communities. p. 216–228. In Proc. Annu. Manitoba Soc. of Soil Sci. Meet., 43rd, Winnipeg, MB, Canada. 25–26 Jan. 2000.

6. Singh, K.P. (2004). IPM in rice wheat cropping system. Research Bulletin No.132. Directorate of Experiment Station, Pantnagar, 2004. p. 16-18.

7. Singh, R., Malik, R.K., Singh, S., Yadav, A. and Duveiller, E. 2002. Influence of zero tillage in wheat on population dynamics of soil fungi and diseases of rice-wheat system. Proceedings of International Workshop on Herbicide Resistance Management and zero tillage in rice-wheat cropping system, Hisar, Haryana, India, pp.177-181.

8. Sturz, A.V., Crater, M.R and Johnston, H.W. 1997. A review of plant disease-pathogen interactions and microbial antagonism under conservation tillage in temperate, humid agriculture. Soil Tillage Res. 41: 169-189.

9. Sumner, D.R., Doupnik, B.L. Jr. and Boosalis, M.G. 1981. Effects of reduced tillage and multiple cropping on plant diseases. Annu. Rev. Phytopathol. 19: 167 -187.

10. Varshney, S., Duveiller, E., Bridge, J., Rutherford, M., Mishra, R., Ambdekar1, S.J. and Singh1 U.S. 2002. Effect of Tillage Practices on Population Dynamics of Soilborne Antagonists in Uttaranchal State, India. In E. Duveiller J. Bridge M. Rutherford and S. Keeling eds. Soil Health and Sustainability of the Rice Wheat- Systems of the Indo-Gangetic Plains. Pp. 25-28.


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Role of Eco-friendly Approaches in Integrated Pests and Disease Management

Ruchira Tiwari

Department of Entomology, GBPUA&T, Pantnagar-263145 ( Uttarakhand)

What is Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is a system designed to provide long-term management

of pests, instead of temporarily eradicating hem. It is the coordinated use of pest and

environmental information with available economic pest control methods to prevent unacceptable

levels of pest damage which is least hazardous to human being, property, and the environment.

Practicing IPM can reduce the use of chemical pesticides entering the environment and can save

money. IPM is based on taking preventive measures, monitoring the crop, assessing the pest

damage, and choosing appropriate measures. Many different tactics are used in IPM, including

cultural practices, biological control agents, chemical pesticides, pest-resistant varieties, physical

barriers etc.

IPM means a pest management system that in the context of the associate environment

and the population dynamics of the pest species, utilizes all suitable techniques and methods in an

compatible manner as possible to maintain the pest population at levels below those causing

economically unacceptable damage or loss. FAO (1967).

IPM based on the following assessments:

Thresholds levels: Thresholds are the levels of pest population at which pest management action

should be initiated/ undertaken to prevent the pests from causing an acceptable damage. The

threshold often is set at the level where the economic losses caused by pest damage would be

greater than the cost of controlling the pests which sometimes are called ‘Economic Thresholds’

(ET). Populations above these thresholds can reach the Economic Injury Level (EIL), where

they cause enough damage for the grower to lose money. At the economic injury level, the cost of

control is equal to the loss of yield or quality that would result otherwise.

Economic-Injury Level (EIL): (Stern et al., 1959): “The lowest population density of a pest that

will cause economic damage; or the amount of pest injury which will justify the cost of control.”

The eco-friendly approaches which are least disruptive to beneficial insect populations are

as follows:

(1) Cultural practices- It means adjustment of agronomic procedures to reduce pest abundance


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or it is a manipulation of the environment to make it less favourable to insect pests. It needs the

basic studies of the life history and habits of the insects, its plants and animal hosts.

(a) Sanitation- It includes ploughing under infested plants after the harvest of the crop. It includes

destruction and pruning of twigs and branches infested with pests , gathering of plant debris which

harbor overwintering infestations or infections.

(b)Tillage- The cultivation of soil in and around crop plants to destroy numerous crop pests either

through mechanical injury or exposure to sunlight or predators e.g. larvae and pupae of cutworm,

gram pod borer, grass hopper etc.

(c)Alterations in sowing time- The early spring planted sugarcane crop is less attacked by early

shoot borer. In tarai region, if spring maize is planted before 15 February the attack of sorghum

shoot fly would be less. The early sowing of chick pea crop on 15th October was least infested

with H. armigera with maximum seed yield in comparison to crop sown on 24th December.(1) Early

sowing is practicable, cheap and environment friendly option to avoid pod borer infestation.

(d)Nutritional disorder-Proper dose of NPK make the crop healthy and less prone to insect and

disease attack.

(e)Improved storage structures – Plastic woven sacks for food grains packages were found

highly effective to control high moisture content.(2)

(f)Crop rotation Adopting of legume crop after a cereal crop reduces attack of white grub on

legumes.

To control nematode, Meloidogyne incognita in french bean, crop rotation like french bean- rice-

sesamum- french bean found effective in reducing the soil population, root galls and egg masses

of nematode and increase in the field of French bean.(3)

(g)Trap crops-Grow okra along with cotton to attract red cotton bug and jassids

Grow pigeon pea along with cotton to attract grey weevil

Sorghum as trap crop in cotton for increasing paratising efficiency of Trichogramma chilonis

against bollworm when grown after 5 rows of cotton.(4)

Dhaincha (Sesbenia bispinosa) was found economical when 4 lines of dhaincha was sown with

the host crop, soybean on the periphery of the field preferred by the females of girdle beetle. (5)

(h) Mixed cropping- The sowing of Wheat+ gram+ mustard crops in mixed form found effective

against termite, gram caterpillar and aphid on their respective host plants.

(i)Intercropping Inter cropping of tomato crop with crucifer crops suppresses pest population of

H. armigera in tomato due to glocosinolate allelochemicals.

cotton with sesame showed control of bollworm complex.

Groundnut crop intercropped with pigeon pea showed lowest incidence as well as % damage of

Spilractia obliqua in ground nut. (6)

(j)Use of resistant plant varieties: Biotechnology (Genetically Modified (GM) or transgenic

crops)- It refers to the crops which express foreign genes isolated from any biological system. On

the basis of three factors which are responsible for the resistance mechanism in plants are :


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Antibiosis, Non-preference and Tolerance for insect pest resistance, a number of genes have been

used for production of GM crops. Bt Cry proteins, tripsin inhibitors, Alpha amylase inhibitors,

potato proteinase inhibitor II (pinII), lectins, cholesterol oxidase, polyphenol oxidase have been

reported to provide insect pest resistance. Bt transgenic crops are potato, tomato, cotton Bt cotton

(bollguard) and tobacco American variety of grapes against Phylloxera, Winter majetin variety of

apple against wooly aphid were found effective.

(2) Mechanical practices-

These are the methods employing manual devices and machines and give immediate

results.

1) Hand picking- For large sized insects ( caterpillars, beetles bugs etc.)

2) Shaking and beating of branches-To dislodge the insects.

3) Banding- The application of sticky bands( alkathene bands) around the tree trunks

to prevent the movement of the insect pests e.g. for mealy bugs

4) Wire gauge screens- The stems or fruits could be surrounded by wire gauge

screens to prevent the attack of borers

5) Trench digging- This is good for trapping the grasshoppers and locusts which

move in bands and afterwards kill them with insecticides.

6) Trapping – The light traps, pheromone traps, baits are being used to lure the insect

pests to get early warning of increasing pest population. The adhesive traps for

catching alate (flying) mustard aphids were evaluated by making a glass jars

painted with mustard yellow colour and then smeared with transparent grease on its

outer surface to get the flying aphids stuck on the surface of the jar. (7)

(3)Biorational approaches-The utilization of naturally produced chemicals that affect insect

behavior, growth or reproduction and suppress the insect population without affecting the

environment. It includes biological control, use of sex pheromones in mating disruption, hormones

that is use to inhibit a biologically active system of living process like chitin synthase inhibitors,

mating disruption hormones and various types of baits used for mass trapping.

(a)Semiochemicals- These are the chemicals that are able to modify the behavior of the

perceiving organism at sub micro and nanogram level.

Pheromones – It is a chemical or a mixture of chemicals that is released to the exterior by an

organism and that causes one or more specific reactions in a receiving organism of the same

species.

Sex pheromones- These can be employed in IPM for three ways- monitoring / survey, mass

trapping and mating disruption of the pests. Insect population can be estimated and new areas

of infestation detected at very early stage. It is used to give warning regarding the outbreak of

the insect pests and determine economic threshold level to decide about the timing of insecticide

applications. An economical sex pheromone, polystyrene trap was fabricated having females of H.

armigera instead of synthetic septum for monitoring Helicoverpa armigera showed good results in


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capturing more number of males in comparison to synthetic septum used.(8)

(b)Botanicals- The plant products and their active constituents played an important role in plant

disease control by combating growth and development of pathogens and inducing resistance in

host plants. Spore germination of Erysiphi pisi (powdery mildew of pea)was affected by 80% by

applying 500ppm of extract of ocimium sanctum, zingiber officinale rhizome and madhuca indica

leaves.(11). The 15% extract of datura, 20% of Azadirachta indica controls bacterial blight of rice

Xanthomonas oryzae var. oryzae. (12). Neem, tulsi and mint are antihelminthic in action. Plant

extracts such as leaf extracts at 10% concentration of Mint, tulsi ,abutilon indicum were found

effective against storage fungi

(Helminthosporium oryzae, Sarocladium oryzae Aspergillus niger, A. flavus) of paddy They

inhibited the fungal mycelia growth aswell as biomass production and spore germination of

pathogen. Garlic bulb extract (40%) water extract was checked against the growth of Aspergillus

niger and A. flavus( stored fungi) showed total inhibition of the growth of fungi. (13). Neem leaves,

neem seed kernel extract, neem oil were found very effective against the larvae of lepidopteran,

coleopteran and dipteran insects.(9,10).

(C) Insect growth regulators ( IGRs) –

(1)Juvenile hormones- The juvenoids like methoprene, hydroprene, fenoxycarb, pyriproxyfen,and

antijuvenoids such as Precocene I and II, ecdysoids (anti moulting hormones and chitin synthetic

inhibitors ( Dimilin) are being employed for the control of insect pests. New insect growth

regulators like flufenoxuron 0.25% and Lufenuron (0.25% ) were found effective caused 80-85%

mortality of 3rd instar larvae of S. obliqua after 96 hrs of treatment. (14,15,) .Anti juvenile hormones

isolated from Plant Ageratum houstonianumis Precocene I and II induced precocious

metamorphosis in the milkweed bug.

(2)Moulting hormones(MHs) represented by ecdysone, ecdysterone and other ecdysteroids

secreted by prothoracic glands are responsible for normal moulting and growth and maturation of

insects. Phyto ecdysterone isolated from dried parts of Ajuga reptans strongly influenced the

metamorphosis of Epilachna beetle .

The exogenous application of this ecdysone at wrong time cause death of insects.

(3) Chitin synthesis inhibitor- A new class of insecticide is Bnzoyl Phenyl Urea (BPU)

analogues that is diflubenzuron, which is commercialized under the name of Dimilin. It inhibited the

last stage of formation of chitin and cent percent mortality was observed in 15 days old larvae of

Spilarctia oblique at 0.1 % concentration after 10 days of treatment. (16). Others are BAY SIR

8514 and IKI 7899, (chlorfluazuron), teflubenzuron, buprofezin. Plumbagin is a naturally occurring

chitin synthesis inhibitor present in the roots of medicinal shrub, Plumbago capensis.

(d)Biological control agents-

To save the natural enemies and pollinators it is required to have idea of the weakest stage

of insect which is transparent as well, is to be targeted for borers moth emergence and larval

hatching period is most preferred time for biocontrol. Most vulnerable stage of insect pest is


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important. Apply insecticide after or before application of biocontrol agents.

(1) Microbials (Pathogens) – When microbial organisms or their products (toxins) are employed

for the control of insects, animals and plants in a particular area is referred as microbial control.

Principal groups of pathogens are —Bacteria Bt, NPV, fungi and nematodes

Bacteria- Entomogenous sporeforming bacteria are more promosing in insect control. The toxic

crystal producing bacteria is Bacillus thuriengensis which is marketed under different commercial

names dipel, centari, thuricide, biosporine, parasporine etc. like Bt kurstaki, Bt aizawai, Bt

thuriengiensis,. The bacteria causes septicemia (multiplication of the bacterial spores) in the

haemocoel of insects.

Viruses- The entomogenous viruses fall in two categories inclusion viruses and non-

inclusion viruses which produce inclusion bodies in the insect body. NPV

NucleoPolyhedrosis Viruses, Cytoplasmic Polyhedrosis Viruses (CPV) and Granulosis

Viruses (GV). NPV affects insect by producing polyhedral bodies which dissolves by the

alkaline gut of the insect midgut and cause death. The insect stops feeding becomes

sluggish and integument becomes fragile. The infected insect climbs to the higher positions

and the dead larvae usually hang by their prolegs (head downwards) and dry down to dark

brown and black

Fungi - Entomopathogenic fungi Beauveria bassiana and Mettarrhizium anisopliae causes

muscardine disease in insects. Biological control of Meliodogyne incognita by the

application of soil fungus, Paecilomyces lilacinus 2g/pot reduced the egg number by

forming mycilia around the eggs and breakdown the female by entering through their

vulva. Seed treatment of cowpea with fungus P. lilacinus together with the application of

organic matter ( leaves of Leuceana leucocephala) into the nematode infested soil one

week prior to the sowing was found to be more effective in reducing root knot nematodes

incidence and increasing the yield of cowpea .(17)

Nematodes- Infective juvenile of Steinernema carpocapsae and Heterorhabditis

transmits bacteria which are lethal to their hosts. They have a wide host range. Infective

juveniles can easily be cultured and stored for extended periods. Different nematode

formulations are available- liquid, granular and foam incorporated.

(2)Macrobial agents like predators and parasitoids are employed for the control of insects. The

4th instar grub of Coccinella beetle is a potential predator of wheat aphid complex. The

consumption of beetle increases with increase in the age of the grubs.(18).

Biological control of weeds:

A leaf beetle, Zygogramma bicolorata , introduced from Mexico for biocontrol of

Parthenium weed. Inoculative release of this beetle (100 pairs of adults/ acre) may be an

important component of Integrated Parthenium weed management.(19).

Animal originated products

Cow urine, cow dung, buffalo urine, biogas are in use, nowadays, to control the insect pest


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infestation and diseases. Biogas (methane and carbondioxide) was successfully used in the

control of stored grain insect pests such as Rhizopertha dominica, Sitotroga cerealella, Corcyra

cephalonica infesting paddy which was carried out in 100 kg capacity of PVC bins over a period of

8 months. It was observed that it had no any adverse effect on seed germination of paddy.(20).

Cold and hot water extracts of urine of buffalo and bullock and milk of goat completely

inhibited mycelia growth of Macrophomina phaseolina causing dry rot in cotton. The cotton seed

germination was also found higher with vigorous growth of seedlings. It has been observed that

buffalo urine retained total toxicity after autoclaving when tested against tomato fusarial wilt

pathogen. (21)

Baffalo urine at 40% concentration (hot water extract, water extract and autoclaved) totally

inhibited the growth of Aspergillus spp. (13). Cow urine alone and in addition with Allium sativum

bulb powder, neem oil and tea leaves was found effective against snails, Lymnaea acuminata.(22).

Neem leaves and cow urine decoction was found promising to control S. Obliqua (23 , 25) and

had negative effect on the larval weight and feeding preference of S. litura (26).

Cow urine against honeybee diseases— A novel approach (Dr. Ruchira Tiwari ) (24)

The effectiveness and feasibility of using an eco-friendly measure, cow urine were

assessed for the first time in preventing and management of bacterial infections of European foul

brood disease (EFB), a wide spread and serious menace of honeybee, Apis mellifera. Application

of cow urine (25 to 100%) as spray twice at weekly interval on infected combs and terramycin

sugar syrup (125 mg/l) as food and spray showed that cow urine at 75 and 100% concentrations

proved most effective and reduced disease infection to below detectable limit in 8-10 days,

respectively as against 20 days in terramycin syrup fed bees. Cow urine treated infected combs

not only showed rapid recovery in disease infection but also promotion of growth of brood whereas

in terramycin fed colonies the queen stops laying eggs for certain period. Re-occurrence of

disease in the cow urine treated combs was also not observed. Other beneficial effects of cow

urine on robbing, aggressiveness, egg laying and adult activities are discussed. The studies

revealed that cow urine can serve as a potential eco-friendly measure for management of EFB in

honeybees.

What is Pest Risk Analysis (PRA)

Pest Risk analysis is a process of investigation, evaluation of information and decision

making with respect to a certain pest, that starts once it is known or determined that this pest is a

quarantine pest. Subsequently, an evaluation of the potential of introduction of the pest into the

country is done along with its economic, social and environmental consequences. With

identification, determination and evaluation done, the process culminates with decision making to

avoid or reduce the probability of entrance or establishment of the pest into the country.

There are generally three initiation points for PRA:

The identification of a pathway, usually an imported commodity, that may allow the


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introduction and/or spread of quarantine pests

The identification of a pest that may qualify as a quarantine pest

The review or revision of phytosanitary policies and priorities.

The PRA process as described in the International Standards For Phytosanitary Measures

(ISPM) is divided into four phases –Pest risk initiation, Pest risk assessment, Pest risk

management and Pest risk communication/documentation.

On the basis of above mentioned eco-friendly approaches, pre-planting discussions,

reviewing activities undertaken during the year and post harvest discussion and interpretation of

results with transfer of new technologies to the farmers and others related with plant protection

makes a sophisticated IPM programme.

REFERENCES

1. Chakravorty, S. and Nath, P. 2006. Effect of time of sowing on the incidence of pod borer, Helicoverpa armigera in chickpea. Indian Journal of Applied Entomology, 20,1 28-32.

2. Khanna, S.C.,Chaurasia, V. and Sundria, M.M. 2004. Suitability of plastic woven sacks for foodgrain packaging-moisture permeability. Annals of Plant Protection Sciences. 12, 1 210-211.

3. Ahmed, J.A. and Chaudhary, B.N. 2004. Management of Meloidogyne incognita in french bean through crop rotation. Annals of Plant Protection Sciences. 12,1, 118-120.

4. Khosa Jaspreet,Virk, J.S. and Brar, K.S. 2008. Role of sorghum as trap crop for increasing parasitizing efficiency of Trichogramma chiolnis against cotton bollworms. Journal of Insect Science. 21,1 , 79-83.

5. Chaudhary, H.R. and Girdhar Gopal. 2006 .Effect of Dhaincha sesbania bispinosa as a trap crop against girdle beetle in soybean. Indian Journal of Applied Entomology, 20,1 80-81.

6. Nath, P. and Singh, A.K. 2004. Effect of intercropping on the population of Bihar hairy caterpillar and leaf damage in groundnut. Annals of Plant Protection Sciences. 12,1, 32-36.

7. Prasad, S. K. 2004. Modified telescopic adhesive trap for catching alate mustard aphids. Annals of Plant Protection Sciences. 12,1 211-213.

8. Krishna Kant and Kanaujia, K.R. 2008. Low cost sex pheromone trap design for monitoring Helicoverpa armigera (Hubner). Journal of Insect Science. 21,1 61-66.

9. Mishra, P.K., Singh, D.P. and Srivastava, J.S. 2007. Bio-efficacy of neemazal, a product of azadirachtin against sclerotial development of Sclerotinia sclerotiorum and Sclerotinia rolfsii. Journal of Eco-friendly Agriculture, 2,2, 175-177.

10. Mallapur, C.P. and Lingappa, S. 2005. Management of chilli pests through indigenous materials. Karnataka Journal of Agricultural Sciences.18 (2): 389-392.

11. Maurya, S. Singh, D.P. Srivastava, J.S. and Singh, U.P. Effect of some plant extracts on pea powdery mildew ( Erysiphe pisi).2004. Annals of Plant Protection Sciences. 12,2, 296-300.

12. Meena, C. and Gopalakrishnan, Jayshree. 2004. Efficacy of plant extracts against bacterial blight ( Xanthomonas oryzae var. oryzae) of rice. Annals of Plant Protection Sciences. 12,2, 344-346

13. Wani, M.A. and Kurucheva,V. 2004. Effect of garlic bulb extract and buffalo urine on the growth of Aspergillus niger and Aspergillus flavus. Annals of Plant Protection Sciences, 12 (1), 221-222.

14. Ramesh Chander and Bhargava, M.C. 2005. Effect of methoprene on the reproductive potential of tobacco caterpillar, Spodoptera litura (Fabricius). Journal of Insect Science, 18 (2), 25-28.

15. Ramesh Chander, Bhargava, M.C and Choudhary, R.K. 2008. Effect of fenoxycarb on adults of


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Spodoptera litura.(Fabricius). Journal of Insect Science, 21 (1), 24-27.

16. Singh , Y.R. Singh, I.S. and Varatharajan, R. 2004. Bioefficacy of IGRs against caterpillars of Spilarctia obliqua. Annals of Plant Protection Sciences,12, (1), 198-201.

17. Hasan, N. 2004. Evaluation of native strain of Paecilomyces lilacinus against Meloidogyne incognita in cowpea followed by Lucerne. Annals of Plant Protection Sciences. 12,2, 121-124.

18. Soni, R. Deol, G.S. and Brar, K.S. 2005. Feeding potential of Coccinella septempunctata (Linn.) on wheat aphid complex in response to level/intensity of food. Journal of Insect Science, 21, (1) 90-92.

19. Kaur, P. and Shenhmar, M. 2006. Seasonal abundance of Zygogramma bicolorata on Parthenium hysterophorus in Punjab. Journal of Insect Science. 19, 129-133.

20. Yadav, S. and Mahla, J.C. 2005. Bioefficacy of carbondioxide concentrations and exposure periods against lesser grain borer, Rhyzopertha dominica, (Fab.) in stored wheat. Journal of Insect Science,18 (2) 84-89.

21. Raja, V. and Kurucheve, V. 1997. Antifungal properties of some animal products against Macrophomina phaseolina causing dry root rot of cotton. Plant Disease Research, 12,1 11-14.

22. Tripathi, R. Singh, V.K. and Singh, D.K. 2006. Freeze dried powder of cow urine reduces the viability of the snail, Lymnaea acuminata. Journal of Pest Science, 79,(3) 143-148.

23. Purwar, J.P. and Yadav, Sri Ram. 2004. Evaluation of age related response of Spilarctia obliqua to biorationals insecticides. Annals of Plant Protection Sciences. 12,2, 271-273.

24. Tiwari, R. and Mall, P. 2007. Efficacy of cow urine for management of European foulbrood disease of honey bee, Apis mellifera (L) at Pantnagar. Journal of Eco-friendly Agriculture, 2,2, 201-203.

25. Aakash Chand and Tiwari R. 2010. Effect of cow urine and some indigenous plant extracts on feeding preference of Spilarctia obliqua (Walker). Journal of Applied Entomology. 24(1), 43-46

26. Aakash Chand and Tiwari R. 2010. Influence of cow urine and indigenous plant leaf extracts on feeding potential and larval weight of Spodoptera litura (Fabricius) (Noctuidae : Lepidoptera). Journal of Insect Science. 23 (3)313-317


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Advances in Electron Microscopy and application in Plant Pathology

Balwinder Singh Dhote Department of Anatomy, G.B.P.U.A.&T., Pantnagar - 263145 (Uttarakhand)

Introduction

One of the most important tasks in the education of a pathologist is learning to distinguish

normal from abnormal tissues. Typically, training

programs provide an adequate background for the

examination and interpretation of tissues at the

gross and light microscopic (lm) levels, leaving the

student pathologist to his/her own devices to

develop necessary skills at the ultrastructural level.

The purpose of this presentation is to facilitate

development of these skills in ultrastructural

examination/interpretation of tissues, by providing a

starting point, some tools for study, direction, and

finally, a goal at which to aim. Since it would be

unrealistic to attempt to go into depth in the short

time allotted, the presentation will concentrate on

an approach to interpretation of ultrastructural

cases while providing a broad overview of some

commonly examined tissues.

A human eye can distinguish two points 0.2mm apart. Man’s quest to see the unseen and

beyond what can be seen with the naked eye led to the discovery of simple magnifying glass that

produces an enlarged image of an object. Further improvement led to development of light

microscopes that use a combination of magnifying glasses/lenses. Dr.Ernst Ruska at the

University of Berlin built the first Electron Microscope (a Transmission Electron Microscope) in

1931 and could get a resolution of 100nm using two magnetic lenses. Today using 5-7 magnetic

lenses in the imaging system a resolution of 0.2nm can be achieved. The introduction of the

electron microscope as a tool for the biologist brought about a complete reappraisal of the micro-

anatomy of biological tissues, organisms and cells. In the early days of its application to biological

materials, it was the tool of anatomists and histologists, and many previously unimagined

structures in cells were revealed. More recent developments in biological specimen preparation

have come from biochemists and physicists who have used the electron microscope to examine

cells and tissue in many different ways.

The two most common types of electron microscopes available commercially are the

TRANSMISSION ELECTRON MICROSCOPE (TEM) and the SCANNING ELECTRON

MICROSCOPE (SEM). In the SEM, the specimen is scanned with a focused beam of electrons


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which produce "secondary" electrons as the beam hits the specimen. These are detected and

converted into an image on a television screen, and a three-dimensional image of the surface of

the specimen is produced. Specimens in the TEM are examined by passing the electron beam

through them, revealing more information of the internal structure of specimens.

The Transmission Electron Microscope (TEM)

The TEM is an evacuated metal cylinder (the column) about 1 to 2 meters high with the

source of illumination, a tungsten filament (the cathode), at the top. If the filament is heated and a

high voltage (the accelerating voltage) of between 40,000 to 100,000 volts is passed between it

and the anode, the filament will emit electrons. These negatively charged electrons are

accelerated to an anode (positive charge) placed just below the filament, some of which pass

through a tiny hole in the anode, to form an electron beam which passes down the column. The

speed at which they are accelerated to the anode depends on the amount of accelerating voltage

present.

Electro-magnets, placed at intervals down the column, focus the electrons, mimicking the

glass lenses on the light microscope. The double condenser lenses focus the electron beam onto

the specimen which is clamped into the removable specimen stage, usually on a specimen grid.

As the electron beam passes through the specimen, some electrons are scattered whilst

the remainder are focused by the objective lens either onto a phosphorescent screen or

photographic film to form an image. Unfocussed electrons are blocked out by the objective

aperture, resulting in an enhancement of the image contrast. The contrast of the image can be

increased by reducing the size of this aperture. The remaining lenses on the TEM are the

intermediate lens and the projector lens. The intermediate lens is used to control magnification.

The projector lens corresponds to the ocular lens of the light microscope and forms a real image

on the fluorescent screen at the base of the microscope column.


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Resolving Power

The human eye can recognize two objects if they are 0.2mm apart at a normal viewing

distance of 25 cm. This ability to optically separate two objects is called resolving power. Any finer

detail than this can be resolved by the eye only if the object is enlarged. This enlargement can be

achieved by the use of optical instruments such as hand lenses, compound light microscopes and

electron microscopes.

Resolution in the light microscope

In the light microscope, the quality of the objective lens plays a major role in determining

the resolving power of the apparatus. The ability to make fine structural detail distinct is expressed

in terms of numerical aperture (NA). The numerical aperture can be expressed as n sinα where n

is the refractive index for the medium through which the light passes (n air =1.00; n water = 1.33; n

oil = 1.4), and α is the angle of one half of the angular aperture of the lens. Light microscope

objective and condenser lenses are usually designated by this NA value.

In a light microscope, a beam of light is directed through a thin object and a combination of

glass lenses provide an image, which can be viewed by our eyes through an eye piece. The image

formed is realistic, because it uses visible multicolor light. Visible light has wave like nature with a

wavelength (λ) of 400-800 nm. Since the resolution cannot be less than half the wavelength (λ),

the ultimate resolution attainable by using the light microscope is 200nm. This corresponds to a

magnification of 1000 times as compared to an eye. Any magnification higher than this will not

resolve more detail but will only give “empty magnification”.

( 1mm = 1000 µm; 1 µm = 1000nm; 1nm = 10 A0 )

Changes in resolution with wavelength (light microscope)

Light source Green Blue Ultraviolet

Wavelength (nm) 546 436 365

Resolution (nm) 190 160 130

Resolution improves with shorter wavelengths of light

It can be seen from the above table that resolving power improves as the wavelength of the

illuminating light decreases. To explain this more fully, the resolving power of the optical system

can be expressed as

where

R is the distance between distinguishable points (in nm),

is the wavelength of the illumination source (in nm),

NA is the numerical aperture of the objective lens.


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The optimal resolving power for a light microscope is obtained with ultraviolet illumination

( = 365) if a system with the optimal NA is used (1.4).

In this example

R = 130.4 nm

In the visible region of the spectrum, blue light has the next shortest wavelength, then

green and finally red. If white light is used for illumination then the applicable wavelength is that for

green. This is in the middle range of the visible spectrum and the region of highest visible

sharpness.

Improvement of resolving power

Due to this limitation of resolving power by light microscopy, other sources of illumination,

with shorter wavelengths than visible light, have been investigated. Early experiments using X-rays

of extremely short wavelength were not pursued further because of the inability to focus these

rays. The first breakthrough in the development of the electron microscope came when Louis de

Broglie advanced his theory that the electron had a dual nature, with characteristics of a particle or

a wave. The demonstration, in 1923 by Busch, that a beam of electrons could be focused by

magnetic or electric fields opened the way for the development of the first electron microscope, in

1932, by Knoll and Ruska. Although the initial development of the electron microscope, in

Germany, was followed by technical improvements in America, the first commercially available

apparatus was marketed by Seimens.

Specimen preparation for TEM

The greatest obstacle to examining biological material with the electron microscope is the

unphysiological conditions to which specimens must be exposed.

Since the material must be exposed to a very high vacuum ( to Torr) when being

examined, it must be dried at some stage in its preparation. The biological specimen must be

stabilized (or fixed) so that its ultrastructure is as close to that in the living material when exposed

to the vacuum.

The limited penetrating power of electrons means that the specimens must be very thin or

must be sliced into thin sections (50 - 100 nm) to allow electrons to pass through.

Contrast in the TEM depends on the atomic number of the atoms in the specimen; the

higher the atomic number, the more electrons are scattered and the greater the contrast.

Biological molecules are composed of atoms of very low atomic number (carbon, hydrogen,

nitrogen, phosphorus and sulphur). Thin sections of biological material are made visible by

selective staining. This is achieved by exposure to salts of heavy metals such as uranium, lead

and osmium, which are electron opaque.

Fixatives are used to prevent autolysis, change in volume and shape and preserve various

chemical constituents of the cell.


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Aims of Fixation

To preserve the structure of cells and tissues with minimum or least alteration from the

living state.

To protect them against alterations during embedding and sectioning.

To prepare them for subsequent treatments such as staining and exposure to the electron

beam

Commonly used Fixatives

Glutaraldehyde

Paraformaldehyde Primary fixative

Acrolein

Karnovsky’s Fixative (Glutaraldehyde + Paraformaldehyde)

Osmium tetroxide Secondary fixative

Some other compounds are also there which have the ability to partially fix or stain the

cellular constituents e.g. Chromium salts, Uranium salts, lead compounds and Phosphotungstic

acid (PTA).

Procedure of Fixation and Block Making

Primary fixation

1-2mm sq thick samples + 2.5% glutaraldehyde made

in 0.1M sodium phosphate buffer (pH 7.4) 2-24 hours at 4°C

Washing

Rinse thoroughly with 0.1 M sodium phosphate buffer (pH 7.4) to wash away excess fixative

Secondary fixation

Osmium tetroxide (1% solution) is commonly used, acts as electron dense stain reacts principally

with lipids.

Washing

Rinse thoroughly with 0.1 M sodium phosphate buffer (pH 7.4) to wash away excess fixative

Dehydration

Ethanol or Dry acetone is used to completely dehydrate the tissue.

Clearing

Xylene, Toluene or epoxy propane is commonly used.

Infiltration

Infiltration is done by gradually decreasing the concentration of clearing agent and proportionately

increasing the concentration of embedding medium.

Infiltration is carried out with liquid resins.

Embedding

Embedding is done in the embedding medium using a gelatin or beam capsule


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Polymerization

Keep the specimen at 40-50°C for overnight for better penetration of the resin and then increase

the temperature to 60°C for 24-48 hrs so that the resin gets hardened.

Removing the Blocks from the mould

After polymerization the blocks can be easily removed.

ULTRAMICROTOMY

Glass knife is used for cutting ultrathin sections. Ultrathin sections show interference colors while

floating on the liquid of the trough. This makes it possible to determine the thickness of the

sections.

Gray-60 nm (600A0 ); optimal for high resolution work.

Silver- 60-90 nm; ideal for most of the purposes.

Gold- 90-150 nm; useful for low magnification and autoradiography.

Purple ,blue,green and yellow- range from 150-320nm; very thick sections and not suitable for

transmission microscopy.

He sections are picked on to the grids to be observed in the TEM

Tem Observations

One of the most important tasks is learning to distinguish normal from abnormal tissues. In

order to successfully interpret an electron microscopic (EM) case, you need some of basic tools

such as a working knowledge of normal. To describe a micrograph:

Begin by stating which tissue(s) is (are) present

Brief description of normal landmarks present

Describe pathologic changes

Have good vocabulary of EM terms - appendix I in the 2nd edition of cell pathology by

Cheville has a glossary of EM terms; this is a good starting point.

Morphologic diagnosis

Same rules apply as for LM cases

Be concise

Example: hepatocyte: degeneration, diffuse, moderate with intranuclear virions.


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Diagnosis must be supported by morphologic description

Hepatocyte PCT Kidney Below is an EM of a young plant cell: note the nucleus (N) surrounded by a double unit membrane;

the cell wall (CW) with its laminated (often amorphous) structure; mitochondria (M) with their

internal cristae, the vacuoles surrounded by a single membrane (tonoplast), and the endoplasmic

reticulum (ER). The dots throughout are ribosomes.

Nucleus: identified by its size, double unit membrane, and granular texture (due to chromatin).

Cell Wall: identified by its laminated or amorphous texture.

Mitochondria: identified by their size, by their double unit membrane, and by the enfoldings of the

inner membrane called cristae.

Plastids: Identified by their double unit membrane.

Leucoplasts can be identified by their absence of cristae or chromatin.Leucoplasts may have

amorphous starch grains, or crystalline protein.

Chloroplasts can be identified by their stacks of thallakoid membranes called grana.

Vacuole - Vacuole membrane: Vacuoles are surrounded by a single unit membrane. The texture

inside is clear - evidence of the absence of other cellular components.

Microbodies: Have a single unit membrane and are usually dense in appearance.

Golgi Bodies: In cross section appear as a stack of membrane-bound compartments resembling

a cross section of a stack of pancakes.


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Endoplasmic Reticulum: Membranes that pervade the cell, seemingly not associated with any of

the structures listed above. If ribosomes are clustered along these membranes is called rough ER.

Ribosomes: dot-like structures often associated with endoplasmic reticulum.

Meristematic cells in roots parenchyma Chloroplast in Leaf Material from Glycine hispida (10000X)

Thicker ascospore walls (TEM) fungus TEM of phytoplasma colonizing the phloem of an infected stem.

Infectious Agent

A complete treatise of ultrastructural detail of infectious agents is beyond the scope of this

presentation. Generally speaking, it is easy to get carried away describing these organisms in any

detail, especially protozoa. It is better to describe the essentials, interpret and continue.

Viral

In describing viruses, describe size if a scale marker is present, shape, encapsulated or

not, appearance of nucleoid, and where virus is present (intranuclear, budding from cell

membranes/ walls, within er, extracellular, etc.).Some viruses are more easily identified

ultrastructurally than others:

Poxviruses- relatively large viruses (200-300 nm), replication in the cytosol unlike most

DNA viruses, substantial capsule and dumbbell-shaped nucleoid.

Adenoviruses- characteristic intranuclear paracrystalline array.

Herpesviruses- replication in nucleus where immature nucleocapsids are present, envelope

by budding through a membrane (often nuclear, sometimes er or plasma membrane).

Bacterial

Be familiar with general ultrastructural morphology of a bacterium. Knowing the species of

plant / animal, the tissue involved, and occasionally some other features, you can make an


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educated guess as to the bacteria with which you are dealing. Describe size if a scale is given,

shape (coccus, rod, pleomorphic) and where bacteria are located (i.e. At microvillar tips, closely-

adhered to cell membrane / wall, intracytoplasmic and if so, within phagolysosome or free).

Pseudomonas putida under solute stress Pseudomonas putida with no stress Examples:

Bordetella- bacteria enmeshed in tracheal cilia; animal affected may be dog, turkey,

etc.Car bacillus- bacteria enmeshed in cilia of airway, but more likely in a rat.

These Helicobacter pylori Bacteria (formerly named Campylobacter) on human stomach

epithelial cells can cause certain types of stomach ulcers and gastritis. Peptic ulcers are holes or

sores in the stomach or duodenum and most are caused by this pathogen. With antibiotics, the

infection can be cured in a few weeks. TEM X40,000

Protozoal

Be familiar with some of the terminology used in describing protozoa, such as conoid,

micronemes and rhoptries. Note whether zoites are contained within a parasitophorous vacuole or

free in the cytoplasm. If in a bradycyst, is wall thick or thin? Some familiar examples include:

Giardia- elongated, attached along microvillar surface

Cryptosporidium- trophozoites attached to apical cell surface by feeder organelle, microvilli

are effaced only at the site of attachment. The trophozoites develop into schizonts.

Journals relating to Electron Microscopy

Journal of Electron Microscopy (Japanese)

Journal of Electron Microscopy Techniques


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Journal of Microscopy

Biology of Cell (French)

Journal of Ultra-structural Pathology

Scanning Electron Microscopy

Ultramicroscopy

Developmental Dynamics

Anatomical Record

Journal of Cell Biology

Tissue and Cell

Electron Microscopy Reviews

Journal of Ultra structure and Molecular Structure Research

Cell and Tissue Research


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Plant Disease Forecasting (Late Blight Forecasting)

V. S. Pundhir Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Diseases vary in consistency of occurrence and severity, thus epidemics are irregular

feature. The growers are often faced with the dilemma: whether to spray or to wait? Agrios (1997)

very aptly described epidemics “they resemble hurricanes”. They come, devastate and vanish.

Pathologists have been successful in understanding the factors responsible for initiation, buildup

and demise of epidemics. Fortunately epidemics follow a predictable course. The understanding

about interactions of four elements of epidemics has been exploited for prediction of

disease/epidemics. Our ability to predict diseases is an indicative of developments in science of

plant pathology. Disease forecasting or warning systems are boon to the growers as it encourages

judicious use (need based) of pesticides. This not only saves the money and energy of the

growers, without risking crop health, but also avoids the environmental pollution.

Miller and O’ Brien (1952) proposed a descriptive definition of disease forecasting that

stands valid even today. They stated, “Forecasting involves all the activities in ascertaining and

notifying the growers of community that conditions are sufficiently favorable for certain diseases,

that application of control measures will result in economic gain, or on the other hand, and just as

important that the amount expected is unlikely to be enough to justify the expenditure of time,

energy and money for control”. The above statement made explicit distinction between positive

forecast and negative forecast and both have value for growers as well as society in general.

Pre-requisites for Developing a Forecast System

Disease forecasting is a complicated, expensive and risky venture, as several biotic and

abiotic factors influence appearance and development of plant disease. The advancements in

science and technology have made ‘Disease warning System’ a working proposition, it requires lot

of expenditure in terms of time, money and technical personnel, following points should be

considered before starting a project on “disease forecasting”:

a. The crop must be a cash crop (economic value)

b. The disease must have potential to cause damage (yield losses)

c. The disease should not be a regular feature (uncertainty)

d. Effective and economic control known (options to growers)

e. Reliable means of communication with farmers, and

f. Farmer should be adaptive and have purchase power.

Disease forecasting systems

Based on the method of development of forecasting system the models may be of two

types. Empirical models are usually based on experience of growers, the scientists or both. Dutch

rules (Van Everdingen, 1926) were developed for late blight forecast based on experience.


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Fundamental Models involve research and experimentation for establishing fruitful relationships,

identifying ‘critical factor(s)’ and relating them with appearance (time and amount) of disease. An

empirical model can be further refined or modified by experimentation. Forecasting systems may

aim on two aspects: Infection forecasting, which is prediction of initial appearance of disease. It is

generally based on amount of primary inoculum and prevailing environmental conditions. In

disease forecasting the emphasis is on further development of disease. Amount of secondary

inoculum and number of infection cycles are important.

The appearance and buildup of plant disease epidemic depends on suitable crop growth

stage (canopy: microclimate) and the establishment of pathogen in the crop. This combination

determines the zero date before which disease outbreaks are rare or of little significance, and

therefore, warrants no control measures. Royle (1993) discussed approaches towards

understanding and predicting epidemics by selecting four fungal pathosystems.

Criterion Used for Disease Forecasting

Every plant disease is a unique ‘story’ and interactions of four variable elements make

every situation ‘a case’. First disease forecasting system in plant pathology was developed for vine

downy mildew (Plasmopara viticola) in 1913 (Muller’s incubation calendar; Germany). For

prediction of plant diseases the criteria used are related with survival of inoculum, production and

dispersal of primary and secondary inoculum and role of vector population. Following criteria are

used for predicting plant diseases:

(a) Weather conditions during non-crop period: The amount of primary inoculum depends on

survivability of pathogenic propagules during non-crop period. This relationship has been exploited

to predict the Stewart’s corn wilt (Stevens, 1934) : The pathogen (Erwinia stewartii) overwinters in

the body of vector, corn flea beetle (Chaetocnema pulecaria). Severe winters (low temperature) kill

vector population, thereby reducing the initial inoculum for the next season. Forecasting of

stewart’s corn wilt can be made based on cumulative winter temperature index (CWTI), is the sum

of mean temperatures of December, January and February months. Following Table gives the

relationship between CWTI and different phases (wilt phase in early stage and leaf blight phase in

mature plant) of the disease.

Relationship of cumulative winter temperature index and different phases of Stewart’s corn wilt.

CWTI (0F) 80 or below 80-85 85-90 90-100 >100

Wilt phase Absent Absent Absent/rare Light/severe Destructive

Leaf blight phase

Only trace Light to moderate

Moderate / severe

Severe Severe

The severity of blue mold of tobacco (Peronospora tabacina) in southern U.S. is predicted

based on winter temperature (January). Above normal temperature means severe and early

appearance of disease. Blue mould warning service has been operative in North America by

Tobacco Disease Council, which keeps the growers and industry aware of location and time of


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appearance and speed of blue mould to help with the timing and intensity of control.

(b). Amount of initial inoculum: This criterion is more important for monocyclic diseases where

the secondary infection does not take place and amount of primary inoculum is related to disease

severity and damage. Amount of primary inoculum present in seed, soil or vector can be estimated

and disease prediction can be made, without much problem. It is being used in case of loose smut

of wheat (Ustilago tritici), potato tuber borne inoculum (bacterial & viral pathogens) and soil borne

inoculum of Sclerotium, Verticillium, Rhizoctonia, nematodes can be estimated and disease can be

forecast. Pea root rot (Aphanomyces euteiches), can be predicted by conducting winter grow out

test in glasshouse. In North America Blue Mold Warning System is operative since 1980s where

based on January temperature the threat to seedbeds is forewarned.

Apple scab forecasting: Apple scab (Venturia inaequalis) is one of the most important diseases

of quality apples. Plants are exposed to attack by the fungal spores for very long period (bud

breaking to fruit maturity). Apple – V. inaequalis system was a fit case for development of

forecasting system to guide the growers for first (prophylactic spray) and further need based

sprays to reduce pesticide usage. Three main criteria were used : (a) quantity of primary inoculum,

measured as ascospore dose / ascospore discharge, (b) phenological stage of apple trees, time of

bud breaking, and (c) infection periods (Mills criteria, discussed in chapter 2) depends on

prevailing weather (temperature, Rh, leaf wetness and rain fall). Apple scab warning services are

operating in Germany, Netherlands, England (CEEFAX: computerized programme managed by

BBC by subscription) and India (Himachal Pradesh). Thakur and Khosla (1999) tested relevance

of Mills infection periods to apple scab prediction and rescheduling fungicide application in

Himachal Pradesh (India). They found that at least three sprays could be saved to control the scab

disease below the economic threshold. Following systems of apple scab forecasting have helped

the growers.

(c) Weather conditions during crop season: Prevailing weather conditions have become major

criteria for diseases forecasting for polycyclic diseases where in addition to amount of primary

inoculum, the multiplication and dispersal of secondary inoculum are weather dependent.

Forecasting of early and late blight of potato, anthracnose and Septoira leaf spot of tomato, wheat

rusts, apple scab, powdery mildew of cucurbits and downy mildew of grapes are made considering

the prevailing weather conditions which determine the amount of disease and damage to the crop.

Jhorar et al. (1992) developed a bio-meteorological model for forecasting Karnal bunt disease of

wheat (N. indica) based on weather conditions in late crop season (heading and anthesis stage).

Humidity thermal index (HTI), having highest correlation was used in forecasting model.

Forecasting late blight of potato: Late blight of potato had been instrumental in development of

various fundamental concepts in plant pathology, and disease forecasting is no exception. The

potato growers in Europe were wise enough to recognize blight weather (Moderate temperature

and lots of moisture: rain, dew or humidity) much earlier than van Everdingen postulated Dutch

rules in 1926. Following are four conditions related with ‘weather’ that could foretell about


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‘appearance’ of late blight in Netherlands.

The Dutch Rules:

Night temperature below dew point for at least 4 hrs,

Minimum temperature of 10 c or slightly above,

Clouds on the next day, and

Rainfall during next 24 hrs of at least 0.1 mm.

NOTABLE CONTRIBUTIONS IN LATE BLIGHT FORECASTING

a. van Everdingen postulated “Dutch rules” in 1926

b. Cook (1947) 7-day moving graph.

c. Hyre (1954) Blight favorable days.

d. Wallin (1962) Severity values

e. Bhattacharya et al. (1970) 7 day moving precipitation

f. Krause et al. (1975) BLITECAST

g. Mac Hardy (1979) Non-computerized model

h. Singh et al. (1980) “JHULSACAST” for Indo-Gangetic plains.

i. Fry and Apple (1983) Integrated host resistance and fungicide weathering in

BLITECAST.

j. Dommermuth (1998) Phytoprog I. late blight warning service

k. Runno and Kopple (2002) NEGFRY

l. Grunwald (2002) Modified and validated SIMCAST

Major breakthrough in late blight forecasting came when Krause et al (1975) with a genius

stroke designed an adjustable matrix using Hyre’s (1947) concept of “blight favorable days” and

Wallen’s (1962) “severity values”. The output of BLITECAST was in the form of recommendations

for the grower, tailor made to his own conditions. The growers of Pennsylvania State could send

the weather data recorded in potato fields to a computer through a telephone at forecasting centre

and get the recommendations. The recommendations to the growers were main attraction of this

centralized disease forecasting system.

BLITECAST and after: BLITECAST was a success story. Mac Hardy (1979) developed a non-

computerized method and Fry and Apple (1983) incorporated factors like host resistance and

fungicide withering in BLITECAST. Several computer based decision systems have been

developed. Hijmans et al. (2000) estimated the global severity of potato late blight with geographic

information system (GIS) – linked disease forecast models. They used Blitecast and Simcast along

with climate database in GIS. They identified zones of high late blight severity, which included the

tropical highlands, Western Europe, the east cost of Canada, northern USA, south-eastern Brazil,

and central-southern China. Major production zones with low late blight severity include the


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western plains of India, north-central China, and the north-western USA. Grunwald et al. (2000)

evaluated TOM-CAST, BLITECAST and SIM-CAST for potato late blight management in Toluca

Valley (Maxico). They found that SIM-CAST was superior over other two systems compared. They

also reported that SIM-CAST accurately allocated fungicide application for susceptible potato

cultivars but needed modifications for resistant cultivars. In 2002 these workers reported field

validation of modified SIM-CAST for potato cultivars with high field resistance. There was

significant reduction in fungicides required on resistant cultivars, without risking crop health. Runno

and Koppel (2002) reported NEGFRY – a computer based programme for control of potato late

blight. NEGFRY is based on two existing models: (a) model for forecasting risk of primary attack

(first spray) and (b) model for timing of subsequent fungicide applications. Hansen et al. (2000)

reported decision support system (PlanteInfo) for the control of late blight via PC-NgFry and

internet based information. The success of this system may be due to its regional character.

The Prognosis is another term used in literature to describe forecasting or warning of

diseases, pests, weeds etc (the noxious organisms). Prognosis is characterized as the prediction

of the outbreak, development and outcome of disease. The objective is to decide in advance

whether expected damage is threatening and whether control measures are to be taken (would be

economically justified). Prognosis has been attempted at two levels: (a) Date prognosis and (b)

Loss prognosis.

Late blight forecasting in India: Early work on late blight forecasting was initiated by Chaudhury

and coworkers in Darjeeling where they developed a 7 day moving graph for predicting late blight

appearance in the area. Later Bhattacharya and coworkers at CPRI, Shimla carried further work.

The precipitation was taken as major criteria, as temperature is generally favorable. The model

developed had two stages of blight forecast in Himachal hills. Singh and co-workers in 1980

developed two-component model for blight forecast in plains (Singh et al. 1999).

Long-range vs. Short-term Forecast

The disease forecasts being made are solely depending on prevailing weather conditions.

Our ability to foretell weather is very limited, so the present day disease forecasts are ‘short term

forecasts’. The farmers get little or no time to protect the crops before the infection sets in (most of

conventional fungicides have only protective function). There is urgent need to predict

‘meteorological events’ in coming days, weeks or months. This may be feasible in future by use of

synoptic weather charts, remote sensing devices and satellite gathered data. This may result in

long term weather forecast as well as long term disease forecasts. The growers will have more

sophisticated and commercially useful forecast and sufficient time to modify the agricultural

practices that may be more economically acceptable.

REFERENCES

1. Bhattocharya, S. K., et al. 1983, Forecasting late blight of Potato in Indian hills. In: BBNagaich et al. (Ed) Potato in developing countries Indian Potato Assoc. CPRI Shimla 20p.

2. Cook, H. T. 1947, Forecasting tomato late blight. Plant Dis Reptr. 31: 245.


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3. Cox, A. and Large E. C. 1960, Potato blight epidemics throughout the world. U. S. Dept. Agric, Agric. Handb. 174, p230.

4. Eversmeyer, J. G., Burleigh, J. R., and Roelfs, A. P., 1973. Equation for predicting wheat stem rust development. Phytopathology 63, 348-351.

5. Horsfall J. G. and Cowling, 1978, How Disease Develops in Populations. In Plant Disease, An Advanced Treatise Vol. Ii. Horsfall and Cowling E. B. Academic Press New York.

6. Horsfall, J. G. and Barrat R. W., 1945. An improved growing system for measuring plant disease. Phytopathol. 35: 655.

7. Hyre, R. A. 1954, Progress in forecasting late blight of potato and tomato. Plant Dis. Rep. 38, 245

8. Krause, R.A. and Massie, L.B. 1975. Predictive systems: Modern approaches to disease control. Annu. Rev. Phytopathol. 13: 31-47.

9. Krause, R.A., Massie, L.B. and Hyre, R.A. 1975. Blightcast: A computerized forecast of potato late blight. Plant Dis. Rep. 59: 95-98.

10. Main, C. E., 1977. Crop destruction-the raison d’etre of plant pathology, In “Plant Disease: An Advanced Treatise” (J.G.Horsfall and E.B. Cowling, eds.), Vol. 1, pp. 55-78. Academic Press, New York.

11. Padmanabhan, S. Y. 1973. The great Bengal Famine. Ann. Rev. Phytopathol. 11:11.

12. Singh, B. P., Singh P. H. and Bhattacharya S. K., 1999, Epidemiology. In: Potato Late Blight in Inia CPRI Tech. Bull. No 27.

13. Stevens, N.E., 1934. Stewart’s disease in relation to winter temperatures. Plant Dis. Rep. 12, 141-149.

14. Waggoner, P.E., 1960. Forecasting epidemics. In “Plant Pathology: An Advanced Treatise” (J.G. Horsfall and A.E.Dimond, eds.) Vol. 3, pp. 291-312. Academic Press, New York.

15. Wallin, J. R. 1962, Summary of recent progress in Predicting late blight epidemics in limited states and Canada. Amer Pot. J. 39: 306

16. Yarwood, CE, 1959. Predisposition. In “Plant Pathology: An Advanced Treatise” (J.G. Horsfall and A.D.Dimore) eds., Vol. 1, pp-512-562. Academic Press. New York


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Recent Molecular Biology Tools for Rhizospheric Community Analysis for Effective Introduction of Bioagents Application for Organic

Agricultural Practices

A.K. Gaur Department of Molecular Biology & Genetic Engineering, G.B.P.U.A.&T., Pantnagar- 263 145 (UK)

Rhizosphere and plant interactions have been realized of utmost importance by virtue of

natural selection of microbial communities most suited its growth. Since rare plants of medicinal

importance and aesthetic values are required to be adopted in different climatic zones for

sustainable harvest, therefore, it becomes necessary job to characterize these rhizospheric

communities more precisely adopting new and advance molecular biology and other specified

tools. Such microbial diversity characterization shall also provide good application approaches of

biofertilizers/ biocontrol agents in organic farming practices. Many of the time culturing practices of

rhizospheric microbes are difficult and as a result denaturing gel electrophoresis, temperature

gradient gel electrophoresis, single strand conformation polymorphism, gene polymorphism,

amplified ribosomal DNA restriction analysis, terminal RFLP, etc techniques could successfully

adopted for microbial characterizations.

Global human population and urbanization in southeast Asian countries posed once again

a major challenge of productivity and food production with an additional issue of at least

sustainable environment adopting ecofreindly practices. While studying biodiversity an important

issue of conserving natural resources and their sustainable harvest has also been emerged.

Products of aesthetic values from rare plants lead toward organic pharming/farming for atleast

nutraceutical development. Therefore, understanding of microbial ecology precisely through

utilizing present day advance tools for better understanding of soil biology at molecular level of

various natural habitat which in turn will help protecting biodiversity at different level.

Introduction

Biofertilizers and biocontrol agents represent broad range of soil microbes, their

introduction in different soils need carefull characterization in terms of composition and structure

with the help of advance technology available such as 16s ribosomal DNA for phylotyping and

redox potential of carbon sources for phenotyping by sequence/ microarray analyses tools which

will allow right type of introduction of agents as bioferilizers/biocontrols in different agroclimatic

zones with special reference to cultivation of medicinal plants.The concept and compilation of

detailed methodology for said applications will be discussed. Biolog

Inc. developed a screening technology,”Phenotype MicroArray” it ia an integrated system of

cellular assays, instrumentation, and bioinformatics software for high-throughput screening of

cells, available for fungal and bacterial cells .Testing process and the technology were

reconfigures a diverse range of phenotypic tests into sets of arrays. Wells are prepared for a total

of 1,920 conditions, hence each well is designed to test a different phenotype in the array. The


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OmniLog® monitored simultaneously thousands of phenotypes and upto 450,000 data points

generated in one 24 h run. Much of known aspects of the cell, directly or indirectly can be

monitored by PM. Recently researcher demonstrated the global effect of the CbrAB and NtrBC

two-component systems of carbon and nitrogen utilization in Pseudomonas aeruginosa which was

characterized by phenotype microarray analyses with single and double mutants and the isogenic

parent strain.

The gene common to all organisms identify by the use of PCR, that allows the identification

of these previously unknown organisms. Genes commonly amplified for this purpose codes for the

RNA sequence of the small subunit (SSU) of the ribosome. Different bacterial genomes were

estimated per gram of soil to occur in terrestrial environments . Extensive diversity of the soil could

be competed by even comprehensive culture collection. In the whole world, many culture-

independent surveys of the microbial diversity in soil had been performed e.g. DGGE, TGGE,

TRFLP, ARDRA. All were based principally on the PCR amplification of the small-subunit rDNA

from directly extracted soil DNA with universal primers. Comprehensive SSU rDNA clone libraries

are subsequently generated by using these amplicons, allowing subsequent sequencing analyses.

Unfortunately, all the studies used different studies used different cell lysis methods and primer

sets. Comparability is thus limited, all these sequence provide the first indication of microbial

diversity based on “real environment” 16S rDNA data. The presence of hitherto unidentified

bacteria demonstrated by the analysis of such 16S rDNA clone libraries, that were remotely

related to known strains. Only a minority of sequences retrieved from directly isolated soil DNA

could be closely related to cultured organisms.

Materials and Methods

Biofilm quantification assay. Biofilm formation assaye by the ability of the cells to adhere to the

wells of microtitre plates made of polystyrene. Bacterial supernatants discarded after incubation ,

and loosely adherent bacteria removed by three washes with phosphate-buffered saline (pH 7.2).

The microtiter plates then inverted and allowed to dry before each well filled with 25µl 0.1% (w/v)

crystal violet (CV) solution and incubated at room temperature for 30 minutes. Unbound CV

removed by three washes with water, and the plates inverted to dry. Cell-bound CV then released

from bacterial cell by the addition of 200µl 95% ethanol and, after incubation at room temperature

for 30 minutes on a rotary shaker, the concentration of CV in each solution determined by the

optical density reading at 590nm (Tecan Infinite 200 Microplate Reader, Ma nnedorf, Switzerland).

Similarly, wells containing only NB but no bacteria were used as negative controls.

EPS quantification assay. Cell suspension of O.D. about 1.0 (600 nm), centrifuge the cell

suspension at 10,000 rpm for 10 min. The sedimented material is used for the total carbohydrate

assay. To 0.5 ml sample grown in NB/LB, add ml phenol (5% w/v) then add 1ml sulphuric acid,

incubate it for 1h in dark. Dilute the resultant solution by adding equal volume of water to the

material. Incubate for 60 min in dark and measure absorbance at 490 nm.

Alginate quantification assay. Grown bacterial culture in 40 ml of NB for 48 h centrifuged using


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Sorvall RC 5C at 10,000 rpm for 10 min at 4°C. Supernatant was collected in a fresh vessel;

alginate was precipitated by the equal volume of isopropanol by keeping it for one day in static

conditions.Again centrifuge at 10,000 rpm for 10 min and collect the pellet, wash with 70% ethanol

followed by 96% ethanol then dry by keeping at 37°C for 15 min. Dissolve pellet in 500 µl of sterile

DW. 100 µl was used for quantification, dilute it 1:10 fold by adding 900 µl sterile DW to make it 1

ml. Add equal volume of Borate sulfuric acid (10mM H3BO3 in Conc. H2SO4), then 30 µl of

Carbazole reagent (0.1% in ethanol) added. Distinguishable purple colour develops; absorbance

of the mixture has been taken at 500 nm. Alginate can be calculated in terms of mg/g wet

biomass using alginate from sea weed as a standard.

Characterization of clones

Restriction mapping. In order to construct the restriction map of the recombinant positive clone

digestion is required with a number of respriction enzymes. The restriction enzymes selected form

the multiple cloning sites usually common amongst them are Eco RI, Xho I and Hind III. Digestion

with restriction endonucleases generally carried out as per the conditions recommended by the

manufacture(s) of the restriction endonucleases. The restriction digestion pattern analyzed on

0.8% agarose gel along with λ DNA Eco RI + Hind III double digest as marker for fragment size

determinations. After electrophoresis, the gel was stained with ethidium bromide and visualized in

UV light.

Sequencing of cloned fragment. The nucleotide sequence of the cloned DNA requires to be

determind on DNA sequencer. Initially universal sequencing primers were used subsequent

sequencing was accomplished by primer walking.

Analysis of sequences. Nucleotide sequences of the plasmid analysis manually performed to

find the insert DNA sequence. Sequences beyond the matched sequences of vector treated as

insert sequences. Insert sequences matched for nucleotide-nucleotide homology by using the

BLAST search (www.ncbi.nlm.nih.gov) and hosted tools of website www.justbio.com used to

create inverse complementary sequences, sequences oriented in same frame then aligned

manually to get a complete sequence in same orientation.

Phenotype microarray

Phenotypic microarray analysis is a recently developed analytical tool to determine the

phenotype of an organism. This technique can be useful to understand the growth changes of an

organism when changing medium, temperature, or adding a stressor, or when testing mutant

strains. The plates, which are commercially available from Biolog (Hayward, CA), consist of array

of 20 plates, The first eight plates test a variety of metabolic agents, including electron donors,

acceptors, and amion acids. Plates 9 and 10 cover a pH and osmotic stressors, while plates 11-20

contain a variety of inhibitors, including toxic agents and antibiotics. The layouts of the 2,000 PM

tests, PM 1-8 test the main catabolic pathways in cells for carbon, nitrogen, phosphorus and

sulphur, as well as biosynthetic pathways. PM9 tests osmotic and ion effects on the cell. PM10

primarily tests pH growth range and pH regulation.


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Community profiling on biochemical basis

Substrate utilization from rhizosphere of a plant under different treatment could be

determined using (Biolog Inc., Hayward, California, USA). The rate of utilization is indicated by

tetrazolium reduction with the help of dye, on the basis of colour change. Suitable aliquots were

used into microplate wells, after incubation of these plate at 30°C. The absorbancy was measured

using visible microplate reader as per Garland (1996). Diversity indices and related were

calculated using formula described by Derry et al.(1998).

Results and Discussion

It is inferred that in the environment the bacterial communities were composed mainly of

uncultured species. The production of clone libraries, however limits the number of samples and

time-consuming that can be analyzed and compared with each other. The number of samples that

can be analyzed may be a critical factor for many ecological studies, because the natural

variability of a community needs to be differentiated from effects that were triggered by a changing

environmental condition. Since, to promote the circulation of plant nutrients and reduce the need

for chemical fertilizers microorganisms are most important, therefore, rhizosphere bacterial

communities could be explored for reasonably correct identification by use of culture-dependent

and culture-independent methods, in relation to variables such as the host plant species and soil

properties. Rhizosphere bacterial communities characterization methods involved soil sampling

followed by bacterial community assessment, as well as the magnitude of interactions that can

result from different plant/soil/environmental systems for biopharming practices.

REFERENCES

1. Bochner BR (1989) Sleuthing out bacterial identities. Nature339, 157-158.

2. Bochner BR (2003) New technologies to assess genotype-phenotype relationships. Nat Rev Genet 4, 309-314.

3. Bochner BR, Gadzinski P and Panomitros E (2001) Phenotype microarray for high throughput phenotypic testing and assay of gene function. Genome Res 11,1246-1255.

4. Derry AM, Staddon WJ and Trevors JT (1998) Functional diversity and community structure of microorganisms in uncontaminated and creosote-contaminated soils as determined by sole-carbon-source-utilization, World J Microbiol Biotechnol 14, 571-578.

5. Garland JL (1996) patterns of potential C source utilization by rhizosphere communities. Soil Biol Biochem 28 223-230.

6. Marshall MM, Amos RN, Henrich VC and Rublee PA (2008) Developing SSU rDNA metagenomic profiles of aquatic microbial communities for environmental assessments. Ecological Indicators 8, 442-453.

7. Schmalenberger A and Tebbe GC (2003) Bacterial diversity in maize rhizospheres conclusion on the use of genetic profiles based on PCR-amplified partial small subunit rRNA genes in ecological studies. Mol Ecol 12, 251-262.

8. Torsvik V, Goksǿyrn J and Daae FL (1990) High diversity in DNA of soil bacteria. Appl Environ Microbiol 56, 782-787.

9. Von Eiff C, McNamara P, Becker K, Bates D, Lei X-,Ziman M, Bochner BR, Petres G and Proctor RA (2006) Phenotype Microarray profiling of Staphylococcus aureus mend and hemB mutantwith the Small-Colony-variant phenotype. J Bacteriol 188, 688-693.


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10. Wang M, Chen J-K, Li B (2007) Characterization of bacterial community structure and diversity in rhizosphere soils of three plants in rapidly changing salt marshes using 16s rDNA. Pedosphere 17, 545-556.

11. Zhang W, Ki J-S and Qian P-Y (2008) Microbial diversity in polluted harbor sediments I: Bacterial community assessment based on four clone libraries of 16s rDNA. Estuarine Coastal and Shelf Science 76, 668-681.

12. Zhang XX and Rainey PB (2008) Dual involvement of CbrAB and NtrBC in the regulation of histidine utilization in Pseudomonas fluorescens SBW25. Genetics 178, 185-195.


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GIS Application in Precision Farming and Plant Disease Management

A.K. Agnihotri Department of Soil Science, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Introduction to GIS

Definition

Definitions of GIS (short for "Geographic Information Systems") vary considerably.

One such definition is as follows.

GIS is a computer-based information management technology used by people for handling

spatial/geographic data or geographically-referenced data.

There are two important aspects in the definition of GIS:

Components of GIS

There are four basic components of a GIS - i.e., people managing data by formulating

tasks using software running on hardware.

Functions of GIS

With these basic components, GIS can be used to perform the following functions:

Data handling (i.e. capturing, organizing, storing)

Data manipulation (i.e. processing, analyzing)

Data output (i.e. displaying)

GIS Applications

GIS as an information management tool can be used over a spectrum of developmental

stages from the most basic to the most sophisticated. GIS techniques can be applied to a wide

variety of problem-solving situations in practically any field of human endeavor where maps or

geographical information are used.

Three basic types of GIS applications that represent the stages of development (with

increasing sophistication) in the use of GIS technology are

1 inventory applications,

2 analysis applications, and

3 management applications.

At its most basic level, GIS is used as an information management tool - a method of

integrating spatial data (e.g., maps and satellite images) and textual/tabular data (e.g., census,

soils, and climate) within a single, retrievable data base. At the advanced level, GIS can be used

as a tool for modeling and testing hypotheses, such as on land/resource use scenarios, ecosystem

change and evaluation of technology suitability .

Inventory Applications

Often the first step in developing a GIS application is making an inventory of the subjects

you want to study for a given geographic area, e.g. soils, land cover/land use, human settlements,

infrastructure, etc. These subjects are represented in the GIS as layers or themes of data. At this


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basic level, the GIS is used as an information handling tool --- a method of integrating spatial data

( e.g., maps and satellite images) and textual/tabular data ( e.g., census, soils, and climate) within

a data base whereby the component layers may be retrieved, displayed, printed out and updated.

Analysis Applications

Once the GIS data base is set up, you would usually want to get value-added information

from the data. This can range from carrying out simple to complex queries involving multiple data

layers to more complex analysis on the data layers. Most GIS have a variety of spatial analysis

tools to manipulate map layers and their associated data.

Management Applications

More advanced spatial analysis and modeling techniques are needed to address real world

problems. At this stage of application, GIS, on its own or linked with other tools, may be used to

help managers and policy makers in making decisions based on a rational use of a sound

knowledge base.

What you can do with a GIS?

Identifying Features

With a GIS, you can ask questions about the data sets created. There are two main kinds

of questions that the GIS can answer:

I. Querying - what exists at a particular location?

You specify the object/feature for which you want information by

o pointing at an object or region of a displayed map

o typing the identifier for the object you select

o typing in a geographical coordinate location

After specifying the object/feature or location, you can obtain a list of

o all of its characteristics some of its characteristics

o some of its’ characteristics

2. Locating by specifying conditions - where are the objects/features which satisfy a

particular set of conditions?

You can specify one condition or a set of conditions by stringing them up in logical

expressions.

Performing Geographical Analyses

You can analyze data to obtain.

o answers to a particular question

o solutions to a particular problem

GIS can carry out many different types of spatial operations on the data stored in the GIS data

base, or on data from other software which are linked to the GIS data sets.

Spatial operations may be applied to.

o existing map(s)

o attribute data associated with existing map(s)


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The result of spatial operations may be.

o new map(s)

o tabular data

o graphics, e.g. line graphs, bar charts, etc..

When spatial operations are performed on two or more map layers, we refer to the

operations as map overlays. Spatial operations performed on multiple map layers may be thought

of as map algebra. The map algebra concept is an extension of the algebra operation on

numbers.

Instead of operating on single numbers, the spatial operator acts on whole map layers. In the

raster mode, the operator acts on the geographically equivalent cells of the map layers.

By stringing together various spatial operations, the GIS can be used to solve complex problems

using geographically-referenced data.

Concept of Map Overlays

Vector mode Raster mode


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THE NATURE AND REPRESENTATION OF GEOGRAPHIC DATA

THE NATURE OF GEOGRAPHIC DATA

The world is infinitely complex and full of variation; the closer one looks, the more detail is

seen, ad infinitum. It would therefore take an infinitely large data base to represent the real world

accurately. Therefore data must somehow be reduced to a finite and manageable quantity by

abstraction and generalization. Real-world entities must be represented by discrete objects with

associated attributes and geographical data must give information about

a. position

b. attribute

c. possible topological relationships

Spatial objects representing real-world entities with finite area. The real-world entities

which are represented as areas also depend on the scale of the map ( e.g., on a large scale map,

streams are represented by areas, although slim, elongated areas while on a small scale map,

streams are represented by lines). Boundaries may be natural or man-made.

Representation of geographic objects in computerised GIS

In computerized GIS, map information that we normally see in paper maps would need to

be converted to digital form.

Analog Representation

This is more familiar to ordinary users of maps. Points, lines, and areas are drawn with a

certain amount of locational accuracy on a 2-D surface like a piece of paper, and referenced to

locations on the earth's surface by using some standard system of coordinates, e.g. national grid,

or an internationally-accepted map projection. Objects drawn on the map may be stylized and

symbolized or color-coded, attributes may also be directly labeled onto objects or is shown in a

legend. Topological relationships are inferred visually by the map reader. A map sheet can contain

a. single entity type or theme, i.e., thematic map, such as soil map

b. Several entity types e.g., topographic maps have contours, rivers, cultural features such

as towns, bridges, etc.

Digital Representation

A map, in the paper form that we are familiar with, cannot exist in the computer. While the

human eye (and brain) is adept at recognizing shapes and inferring spatial relationships among

objects, the computer needs to be instructed specifically how spatial patterns should be recorded,

handled and displayed. The locational, attribute, and topological information inherent in spatial

data must be represented or encoded into the spatial data base. The manner in which the

information is represented is defined by the spatial data base model, there are two main kinds of

spatial data models, i.e., raster and vector models. In simple terms,

a. A raster model tells what occurs everywhere, at each place/cell in the entire study area.

b. A vector model tells where everything occurs, i.e., by giving a location to every object


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which one intends to map

Whichever the model, spatial data for a study area are organized into a set of layers

(coverages or themes ), each layer may represent a single entity type. However, it is not usual for

distinctly different entity types to be combined in a layer, such as is normally seen in an analog

topographic map. Generally, separation of the complex, realworld features by layers makes spatial

data more easily handled in the GIS. The user cannot "see" the digital spatial data base directly for

it would not make much sense; in order to convert the digital data to comprehensible display would

require certain software commands to retrieve data from the data base and display them on some

output device.

Vector data structure

The Data Model

The objects of a map are defined by tracing its boundaries or locations in relation to a

geographic reference frame. The fundamental primitive is a point, objects are created by

connecting points with straight lines or with splines. The vector data file is therefore a list of points

making up arcs, arcs making up areas, with explicit documentation of membership and topology

and with associated attribute usually kept in a separate file.

Raster data structure

The Data Model

Raster model divides the entire study area into a regular grid of cells arranged neatly in

rows. Each cell contains a single value; the value given to a cell depends on the type of entity

being encoded, and the type allowable by the GIS software; it can be:

Precision Farming Terminology

Precision farming is a comprehensive approach to farm management and has the following

goals and outcomes: increased profitability and sustainability, improved product quality, effective

and efficient pest management, energy, water and soil conservation, and surface and ground

water protection.. These terms may be confusing at first, but you will soon become familiar with the

language of PF.

Precision Farming vs. Traditional Agriculture

In PF, the farm field is broken into "management zones" based on soil pH, yield rates, pest

infestation, and other factors that affect crop production. Management decisions are based on the

requirements of each zone and PF tools (e.g. GPS/GIS) are used to control zone inputs. In

contrast, traditional farming methods have used a "whole field" approach where the field is treated

as a homogeneous area. Decisions are based on field averages and inputs are applied uniformly

across a field in traditional farming. The advantage of PF is that management zones with a higher

potential for economic return receive more inputs, if needed, than less productive areas.

Therefore, the maximum economic return can be achieved for each input.

Information, Technology, and Decision Support

PF relies on three main elements: information, technology, and decision support

(management).


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Information

Timely and accurate information is the modern farmer's most valuable resource. This

information should include data on crop characteristics, hybrid responses, soil properties, fertility

requirements, weather predictions, weed and pest populations, plant growth responses, harvest

yield, post harvest processing, and marketing projections. Precision farmers must find, analyze,

and use the available information at each step in the crop system. An enormous database is

available on the internet. This data is both accessible and quickly updated.

Technology

Precision farmers must assess how new technologies can be adapted to their operations.

For example, the personal computer (PC) can be used to effectively organize, analyze, and

manage data. Record keeping is easy on a PC and information from past years can be easily

accessed. Computer software including spreadsheets, databases, geographic information systems

(GIS), and other types of application software are readily available and most are easy to use.

Another technology that precision farmers use is the global positioning system (GPS). GPS

allows producers and agricultural consultants to locate specific field positions within a few feet of

accuracy. As a result, numerous observations and measurements can be taken at a specific

position. Global information systems (GIS) can be used to create field maps based on GPS data to

record and assess the impact of farm management decisions. Data sensors used to monitor soil

properties, crop stress, growth conditions, yields, or post harvest processing are either available or

under development. These sensors provide the precision farmer with instant (real-time)

information that can be used to adjust or control operational inputs.

Precision farming uses three general technologies or sets of tools: crop, soil, and

positioning sensors - these include both remote and vehicle-mounted, "on-the-go" sensors that

detect soil texture, soil moisture levels, crop stress, and disease and weed infestations;

Machine controls - these are used to guide field equipment and can vary the rate, mix, and

location of water, seeds, nutrients, or chemical applications;

Computer-based systems - these include GIS maps and databases that use sensor

information to "prescribe" specific machine controls.

Decision support combines traditional management skills with precision farming tools to

help precision farmers make the best management choices or "prescriptions" for their crop

production system Unfortunately, decision support has many times been either unreliable or

difficult to understand. Building databases based on the relationships between input and potential

yields, refining analytical tools, and increasing agronomic knowledge at the local level are yet to be

accomplished. Most agricultural researchers agree that decision support remains the least

developed area of PF. Diagnostic and database development will eventually replace technologies

as the real benefit of PF.

It would be easy to predict the incidence of the plant disease if weather conditions are

recorded properly and an effective data base is prepared for precise decision support. It would be

easier to handle the plant disease if farmers are fore-warned and chemicals are made available in

time to farmers.


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Nanotechnology: A Modern Tool for Precision Farming

K. P. Singh Department of Biophysics & Nanotechnology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

1. What is Nanotechnology?

Nanotechnology is the manipulation or self-assembly of individual atoms, molecules, or

molecular clusters into structures to create materials and devices with new or vastly different

properties. Nanotechnology can work from the top down (which means reducing the size of the

smallest structures to the nanoscale e.g. photonics applications in nanoelectronics and

nanoengineering) or the bottom up (which involves manipulating individual atoms and molecules

into nanostructures and more closely resembles chemistry or biology).

The definition of nanotechnology is based on the prefix “nano” which is from the Greek

word meaning “dwarf”. In more technical terms, the word “nano” means 10-9, or one billionth of

something. For comparison, a virus is roughly 100 nanometres (nm) in size. The word

nanotechnology is generally used when referring to materials with the size of 0.1 to 100

nanometres, however it is also inherent that these materials should display different properties

from bulk (or micrometric and larger) materials as a result of their size. These differences include

physical strength, chemical reactivity, electrical conductance, magnetism, and optical effects.

Nanotechnology allows scientists to create materials and structures at the molecular level. These

nanomaterials have following important characteristics.

1. Chemical and physical properties can become size dependent at the nanoscale.

2. Physical forces have different relative importance at the nanoscale than at macroscopic

length scale.

3. Some physical laws don’t hold at the nanoscale.

4. Fairly complex nanostructures can be constructed by selfassembly. They can build

themselves!

5. Seemingly small changes in structure at the nanoscale can lead to big changes in chemical

or physical properties.

Due to these specific characteristics there are plenty of applications of these nanomaterials

in various fields like biomedical, molecular diagnostics, engineering, Nanobiotechnology etc. In the

food industry, nanotechnology is being used to create better packaging and healthier foods. For

example, researchers are working on creating food packages embedded with tiny materials

specifically designed to alert consumers that a product is no longer safe to eat. Food scientists

also are creating nanomaterials whose small size gives the ability to deliver powerful nutrients to

human cells where they previously could not reach. In addition, scientists believe nanomaterials

can be designed to block certain substances in food, such as harmful cholesterol or food

allergens, from reaching certain parts of the body.

Farm applications of nanotechnology are also commanding attention. Nanomaterials are


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being developed that offer the opportunity to more efficiently and safely administer pesticides,

herbicides, and fertilizers by controlling precisely when and where they are released. For example,

an environmentally friendly pesticide is in development that uses nanomaterials to release its

pestkilling properties only when it is inside the targeted insect. For livestock, the ability of certain

nanomaterials to control dosage could reduce the amount of growth hormones needed to boost

livestock production. There also are nanomaterials in the late stages of development that can

detect and neutralize animal pathogens in livestock before they reach consumers. These

nanosensors are being started to be used in precision farming through Ethernet or wireless

attachments.

1.1 Nanotechnology in Agriculture

Nanotechnology has the potential to revolutionize the agricultural and food industry with

new tools for the molecular treatment of diseases, rapid disease detection, enhancing the ability of

plants to absorb nutrients etc. Smart sensors and smart delivery systems will help the agricultural

industry combat viruses and other crop pathogens. In the near future nanostructured catalysts will

be available which will increase the efficiency of pesticides and herbicides, allowing lower doses to

be used.

Nanotechnology will also protect the environment indirectly through the use of alternative

(renewable) energy supplies, and filters or catalysts to reduce pollution and clean-up existing

pollutants. An agricultural methodology widely used in the USA, Europe and Japan less used in

India, which efficiently utilises modern technology for crop management, is called Controlled

Environment Agriculture (CEA). CEA is an advanced and intensive form of hydroponically-based

agriculture. Plants are grown within a controlled environment so that horticultural practices can be

optimized. The computerized system monitors and regulates localised environments such as fields

of crops. CEA technology, as it exists today, provides an excellent platform for the introduction of

nanotechnology to agriculture. With many of the monitoring and control systems already in place,

nanotechnological devices for CEA that provide “scouting” capabilities could tremendously

improve the grower’s ability to determine the best time of harvest for the crop, the vitality of the

crop, and food security issues, such as microbial or chemical contamination.

1.2 Nano market

Nanotechnology has been described as the new industrial revolution and both developed

and developing countries are investing in this technology to secure a market share. At present the

USA leads with a 4 year, 3.7 billion USD investments through its National Nanotechnology

Initiative (NNI). The USA is followed by Japan and the European Union, which have both

committed substantial funds (750 million and 1.2 billion, including individual country contributions,

respectively per year). The level of funding in developing countries may be comparatively lower,

however this has not lessened the impact of some countries on the global stage. For example,

China's share of academic publications in nanoscale science and engineering topics rose from

7.5% in 1995 to 18.3% in 2004, taking the country from fifth to second in the world. Others such as


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India, South Korea, Iran, and Thailand are also catching up with a focus on applications specific to

the economic growth and needs of their countries. Iran for example has a focused programme in

nanotechnology for the agricultural and food industry. The report suggests that with more than

50% of the world population, the largest market for Nanofood in 2010 will be Asia lead by China.

2. What is Precision Farming?

“Precision farming,” also known as site-specific management, describes a bundle of new

information technologies applied to the management of large-scale, commercial agriculture.

Precision farming technologies include, for example: personal computers, satellite-positioning

systems, geographic information systems, automated machine guidance, remote sensing devices

and telecommunications.

2.1 A Brief Case Study of Precision Farming

“It is 5 a.m. A farmer sips coffee in front of a computer. Up-to-the-minute satellite images

show a weed problem in a field on the north-west corner of the farm. At 6:30 a.m., the farmer

drives to the exact location to apply a precise amount of herbicide.” – A Laboratory for Agricultural

Remote Sensing press release.

2.2 How Does Precision Farming Work?

Precision farming relies upon intensive sensing of environmental conditions and computer

processing of the resulting data to inform decision-making and control farm machinery. Precision

farming technologies typically connect global positioning systems (GPS) with satellite imaging of

fields to remotely sense crop pests or evidence of drought, and then automatically adjust levels of

irrigation or pesticide applications as the tractor moves around the field. Yield monitors fitted to

combine harvesters measure the amount and moisture levels of grains as they are harvested on

different parts of a field, generating computer models that will guide decisions about application or

timing of inputs.

2.3 What are the Benefits of Precision Agriculture?

Precision agriculture promises higher yields and lower input costs by streamlining

agricultural management and thereby reducing waste and labour costs. It also offers the potential

to employ less skilled, and therefore cheaper, farm machinery operators since, theoretically, such

systems can simplify and centralize decision-making. In the future, precision farming will resemble

robotic farming as farm machinery is designed to operate autonomously, continuously adapting to

incoming data.

2.4 The Role of Networks of Wireless Nanosensors in Precision Farming

If they function as designed, ubiquitous wireless sensors will become an essential tool for

bringing this vision of precision farming to maturity. When scattered on fields, networked sensors

are expected to provide detailed data on crop and soil conditions and relay that information in real

time to a remote location so that crop scouting will no longer require the farmer to get their boots

dirty. Since many of the conditions that a farmer may want to monitor (e.g., the presence of plant

viruses or the level of soil nutrients) operate at the nano-scale, and because surfaces can be


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altered at the nano-scale to bind selectively with particular biological proteins, sensors with nano-

scale sensitivity will be particularly important in realizing this vision.

2.5 Smart Fields’ Monitored by Wireless Nanosensors

Agricultural nanosensors development is one of their most important research priorities of

most of the advanced research group worldwide. They are working to promote and develop a total

“Smart Field System” that automatically detects, locates, reports and applies water, fertilisers and

pesticides - going beyond sensing to automatic application.

2.6 What is ‘Smart Dust’?

The idea that thousands of tiny sensors could be scattered like invisible eyes, ears and

noses across farm fields and battlefields sounds like science fiction. Scientists are in a way to

develop autonomous sensors that would each be the size of a match head. Using silicon-etching

technology, these motes (“smart dust” sensors) would feature an onboard power supply,

computation abilities and the ability to detect and then communicate with other motes in the

vicinity. In this way the individual motes would self-organize into ad hoc computer networks

capable of relaying data using wireless (i.e., radio) technology.

3. Membrane Made from Organic Waste Matter Could Help Crops Conserve Water

Researchers have developed a nanoporous membrane made from organic waste

materials, such as seaweed, fish bones, and manure that can prevent water loss from soil and

plant roots and regulate soil temperature in regions that are excessively arid, hot, or cold. Tests

performed on the membrane in the desert soils indicated that the technology reduced the need for

irrigation by 30 to 50 percent. Different pigments can also be added to the membranes to increase

or decrease sun reflection, depending on whether the soil requires heating or cooling.

4. Conclusion

Precision farming has been a long-desired goal to maximise output (i.e. crop yields) while

minimising input (i.e. fertilisers, pesticides, herbicides, etc) through monitoring environmental

variables and applying targeted action. Precision farming makes use of computers, global satellite

positioning systems, and remote sensing devices to measure highly localised environmental

conditions thus determining whether crops are growing at maximum efficiency or precisely

identifying the nature and location of problems. By using centralised data to determine soil

conditions and plant development, seeding, fertilizer, chemical and water use can be fine-tuned to

lower production costs and potentially increase production- all benefiting the farmer. Precision

farming can also help to reduce agricultural waste and thus keep environmental pollution to a

minimum. Although not fully implemented yet, tiny sensors/nanosensors and monitoring systems

enabled by nanotechnology or its oriented applications will have a large impact on future precision

farming methodologies. One of the major roles for nanotechnology-enabled devices will be the

increased use of autonomous sensors/nanosensors linked into a GPS system for real-time

monitoring. These nanosensors could be distributed throughout the field where they can monitor

soil conditions and crop growth. These nanosensors can also play a pivotal role in mobile testing,


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referral and analysis laboratory for rapid screening of physical chemical and pathogenic entities.

5. Further Reading

The interested reader is directed to the following sources which offer a more detailed

analysis of nanotechnology applications in the agricultural and food industries than could be

provided in this manuscript:

1. Down on the Farm” – published by the ETC Group (2004)

www.etcgroup.org/documents/ETC_DOTFarm2004.pdf

2. Nanoscale Science and Engineering for Agriculture and Food Systems” – a report from the

USDA workshop (2003) www.nseafs.cornell.edu/web.roadmap.pdf

3. The Woodrow Wilson International Center for Scholars “Project on Emerging

Nanotechnologies” www.nanotechproject.org

4. A review of potential implications of nanotechnologies for regulations and risk

assessment in relation to food” – published by the Food Standards Agency (2006)

www.food.gov.uk/multimedia/pdfs/nanotech.pdf

5. The Institute of Food Science & Technology statement on Nanotechnology

www.ifst.org/uploadedfiles/cms/store/ATTACHMENTS/Nanotechnology.pdf

6. The European Technology Platform “Food for Life”

http://etp.ciaa.be/asp/about_etp/welcome.asp

7. NANOFOREST - A nanotechnology roadmap for the forest products industry” – published

by STFI-Packforsk (2005) www.stfi-ackforsk.se/upload/3352/Finalroadhem.pdf

8. Science for Agricultural Development - Changing contexts, new opportunities” – published

by the Science Council of the Consultative Group on International Agricultural Research

www.cgiar.org/enews/december2005/scienceforagrdev.pdf

9. Nanotechnology and the Developing World” - Fabio Salamanca-Buentello, Deepa L.

Persad, Erin B. Court, Douglas K. Martin, Abdallah S. Daar, Peter A. Singer (2005). PLoS

Med 2(4): e97. www.utoronto.ca/jcb/home/documents/PLoS_nanotech.pdf

10. Nanotechnology and the Poor: Opportunities and Risks” – published by the Meridian

Institute (2005) www.meridian-nano.org/gdnp/NanoandPoor.pdf


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Knowledge Transfer: Issues and Expectations

K.P. Singh Department of Plant Pathology, G.B.P.U.A.&T., Pantnagar- 263 145 (Uttarakhand)

India was most successful in gaining from ‘Green Revolution”, the term applied to

successful agricultural experiments in many Third World Countries. There were four basic

elements of Green Revolution in India.

1. Introduction of high yielding crop varieties

2. Move to go for extensive irrigation

3. Extensive use of fertilizers and agro-chemicals and

4. Adoption of intensive cultivation practices.

But Green Revolution has certain limitations as indicated below:

1. The Green Revolution, however impressive, has not succeeded in making India totally and

permanently sufficient in food as even to-day India agricultural output sometimes falls

short of demand.

2. India has failed do extend the concept of availability of quality seed and other planting

material of high yielding varieties to all crops and/ or all regions.

3. It is disturbing to note that there are places like Kalahandi (Orissa) where famine like

conditions have been existing for many years and where starvation deaths have also been

reported.

4. Since early nineties deceleration in total factor productivity, over stress on natural

resources and squeeze in net income of the farmers have been reported. This has

caused discontentment among farming community. One of the important reasons of not

reaching the fruit of Green Revolution to all especially at lower ladder of the society was

failure of conventional development approaches in meeting the needs of resource-poor

people.

Limitation of Traditional Knowledge Transfer Methods:

Expensive: it s very costly to train a chain of extension personnel at district, sub division, block to

village level extension worker, prints extension messages brochures, to understand the new

technology and to answer the possible queries form farmers.

Time consuming process: it takes many actors to understand the message form university/

Zonal Research Station (ZRS)/ Krishi Vigyan Kendra (KVK)/ and deliver it to next layer then to

pass onto farmer.

Erosion in quality of message: student of Training and Visit (T&V) system indicate that the

quality of extension messages gets heavily eroded b the time it reaches the farmers.

Poor Communication Capacity: the flow of the information from research to extension tends to

be to-down, rather than a two-way, interactive process aimed at identifying and solving serious

problems. Also, there is little use of up-to- date communications technology, the capacity of


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traditional extension system is very limited, and the challenge in terms of reaching all the villages

and all the farmers is becoming more and more difficult to meet.

How to improve?

Before we decide the strategies for improvement, it is important to discuss the factors

affecting efficiency of extension:

Better the technology, faster the adoption

Economic viability of the new technology

Infrastructure in terms of available consolidation of holding, availability of farm

machinery, market, irrigation etc. has signigicant influence on the adoption of new

technology.

Input distribution backup

Present Challenges faced by Extension system

Indian extension worker-operating in tough socio-economic environment: The extension

worker has to understand the technical, social, economic, educational and cultural environment he

has to operate in. For this, it is very important that he or she appreciates the multifaceted

problems faced by Indian farmers, viz.

Small and fragmented land holdings,

Inferior per hectare yields as compared to international standards,

Inferior quality of produce,

Sub-standard market facilities,

Poor post harvest and seasonal dependence

Multiple produce in small quantities (lack of specialization) leading to wastages,

Poor storage facilities,

Problem in availability of adequate and timely credit,

Distress sale of produce by farmers,

Poor bargaining power of farmers,

Inefficient markt intelligence,

Exploitation of farmer by commission agents.

Our research and extension systems need to address the changed paradigm like:

Complex and changing consumer demand

Increasing impact of international market

Inadequate information with farmers connect with the market.

Research system should have greater connect with the market.

Critical need to build competitiveness to face imports and to increase share in exports will

be heightened liberalized trade regime.

Need to optimize the use of water resources.

Logistics and transport cost are becoming extremely important.


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Factors Required for Agricultural Development

Research which acts as source of innovations, discoveries, inventions and continuous

improvements.

Extension system which is capable of disseminating useful information to farmers as well

as training and educating them on the utilization of technologies.

Farmers who are willing to improve their productivity and make use of opportunities.

Efficient market channels for ensuring farmer’s benefits.

How Research is Being Done?

Conducted by highly trained researcher

In highly controlled environment

With high inputs

With plenty of labour

Result…? Invariably not adapted by the farmers……!

Reason?

Technology generated is:

Not economically viable;

Not operationally feasible;

Not stable;

Not matching with the farmer’s needs; and

Not compatible with the farmer’s system

Research should address these questions

Will it increase the productivity and by how much?

Will it decrease the coast and by how much?

Will it improve the quality and to what extent?

Will it spare, farmer’s time and resources and by how much?

Whether the farmer needs this piece of time and resources to allocate them to another

activity?

Traditional Top-Down Model of Technology Transfer

Research

Extension

Farmer

Steps in Technology Transfer

Generation

Testing

Adaptation

Integration

Dissemination

Adoption and Diffusion


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Missing Links in Technology Transfer

Education

Training

Participation, and

Motivation

Farmers

Representing the greatest human resources in agriculture

Can be extremely effective, if well involved, motivated and rewarded,

With clear strategies and policies.

Bottom-Up Model of Technology Transfer

Bottom up Model

More emphasis

on

Farmer’s knowledge

Farming situations

and

Farmer’s involvement

at

Every steps

of

Technology

Steps in Technology Generation through Farmer’s Participation

Diagnosis of the situation

Identification of the problem

Development of alternative solution

Experimentation

Evaluation, and

Finally, diffusion of Technology

Expectations from farmer’s end:

Flow of Information for backward linkages and taking care of product for forward

linkages will be of utmost necessity. These issues can be satisfactorily addressed by proper

technology penetration through the use of more and more demonstrations ,providing information

and training.

Participation of farmers at planning stage itself not only to identify himself with the

problem and problem solving processes, but also to own it. Follow up after technology transfer

and feed back from farmers goes a long way in refining the technology and therefore, enhancing

it’s sustainability. Weather and disease forecasting system should be given due attention to reach

to the farmers very timely helping to reduce sudden field losses.


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Some successful models of technology transfer in Plant Protection

IPM modules for major crops and cropping systems e.g. cotton, sugarcane, rice, wheat, pigeon

pea, chickpea etc and IPM for rice- wheat cropping system, sugarcane based cropping system,

pulse based cropping system, cotton based cropping system etc.. has been developed and

successfully transferred .

To have a successful transfer of technology there are certain necessary questions that needs to

be answered which helps in popularizing IPM technology or for that matter any technology :

What to do ?

When to do ?

Why to do ?

How to do ?

What not to do ?

Why not to do ?

The points can be discussed by taking an example, e.g. management of mealy bug in

cotton under IPM:

What to do ? Grow pigeon pea, bajra or maize as border crop.

When to do ? At the time of planting of cotton.

Why to do ? These crops offer least support for the growth and multiplication of mealy bug.

How to do ? Growing two rows of any of these crops on border or as inter crop.

What not to do ? Avoid growing Malvaceous or Solanaceous crops in or in the vicinity of the field.

Why not to do ? Malvaceous and Solanaceous crops are good hosts of mealy bugs.

Therefore, the strategy for improved way of knowledge transfer should be by involving

farmer as co-researcher and educating, considering him the most important human resource in

whole business from very beginning and not believing that the farmer is only to here and do what

ever is said to be done..


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Importance of Multitrophic Interactions for Sucessful Biocontrol of Plant Parasitic Nematodes with Fungal and Bacterial Antagonists

Rakesh Pandey

Central Institute of medicinal and Aromatic Plants (CIMAP-CSIR), P.O. CIMAP, Lucknow – 2260 15,

Soil is a major reservoir of variety of plant pathogens mainly bacteria, fungi and

nematodes, which creates major economic problems in various crops all around the world. Among

different pathogens, plant parasitic nematodes are the most serious pest due to their interaction

with variety of pathogens. Since early times the major economically important agricultural crops

have been plagued by these noxious microscopic organisms that feed on plant root, bud, stem,

crown, leaf, seed, rhizome, sucker, seedling, tuber etc. The damage caused by these nematode

pests to a particular plant depends on crop and cultivars, nematode species, level of nematode

inoculum in soil and their environment. The most severe damage generally occurs, when

susceptible host plants are planted in fields with high levels of nematode inoculums. This results in

low crop production / yield and poor quality. The major crops affected by these noxious pests are,

vegetables, fruits, sugar, cotton, oil seed, pulses, tobacco, tea, coffee, cereals, spices, medicinal

and aromatic plants.

The major symptoms caused by plant parasitic nematodes may be observed on shoots and

roots. The above ground symptoms caused by plant parasitic nematodes are stunting, uneven

plant growth, chlorosis, drying of leaves and wilting etc. Root symptoms caused by nematodes are

distributed very widely due to different kind of plant parasitic nematodes. The most common

symptoms are: root lesions, root pruning, root galling, and cessation of plant roots. Roots

damaged by nematodes can not efficiently use the water moisture and nutrients available in the

soil.

Some kinds of nematodes cause damage to tissues on which they feed (for instance root-

knot and some foliar nematodes); some prevent the growth of the roots; others kill the cells on

which they feed, leaving patches of dead tissue as they move on. Depending on the kinds of

nematodes involved, damage may include galls, stunting, and decay of roots. Nematode infested

roots are often darker in color than healthy roots. Large number plant viruses are transmitted by

variety of ectoparasitic nematode species like Longidorus, Trichodorus, Paratrichodorus and

Xiphinema. There are various estimates of the economic loss caused by nematode. The precise

value can not be determined. Because of its “ small size and hidden way of life” and lack of exact

information on their occurrence and pathogenicity. Estimated overall average annual yield loss on

world major crops due to plant parasitic nematodes is more than 12%. Losses for the 40 crops in

developed nations average 8.8% compared with 14.6% for developing nations. Global crop loss

due to nematode on 21 crops, 15 of which are life sustaining were estimated at $ 85 billion

annually. These figures are staggering, and the real figure, when all crops throughout the world

are considered probably exceeds more than $ 100billion annually.


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Among different plant parasitic nematodes, root-knot nematodes (Meloidogyne spp.) are by

far the most important. Their easily recognized galls on the roots make their presence obvious.

Galls result from growth of plant tissues around juvenile nematode, which feed near the center of

the root. Root-knot gall tissue is firm without a hollow center, and is an integral part of the root;

removing a root-knot gall from a root tears root tissue. Nodules formed on roots of many legumes

because of beneficial Rhizobium spp. (nitrogen-fixing bacteria) and most other natural nodules or

bumps are loosely attached to the root and have hollow centers. Active Rhizobium nodules have a

milky fluid in their centers. The problem of root-knot nematode becomes many folds when the

nematode interacts with other microorganisms dwelling in the same niche. The effect is generally

synergistic resulting in several fold damages to host plant. The major fungi that form the

synergistic effect in association with root-knot nematode are Fusarium, Rhizoctonia, Pythium,

Sclerotium, Curvularia, Phomosis, Aspergillus, Verticillium etc. Root-knot nematode interacts with

different viruses and phytoplasma. and causes more damage to the crops.

To manage various plant parasitic nematodes the chemical nematicides were the major

option but it’s use is now being reappraised due to environment, human health, availability and

cost. Sometimes nematode develop resistance due to its repeated use. Nowadays most of the

effective chemical nematicides have been phase out from the world market and in country like

India we don’t have any major chemical nematicides. Increasing social awareness on

environmental and health concerns associated with the use of synthetic chemicals for nematode

management, urged to search an alternative with biosafety for better and economic management

of nematodes. For sustainable crop production the biological management of plant parasitic

nematodes through use of fungal and bacterial antagonists in cultivated crops becomes a major

tool of interest. Several experiments were carried out to manage root-knot nematode population

through the use of microorganisms. Major emphasis was given on nematophagus fungi, egg

parasitic fungi, nematode parasitic bacteria, PGPR, and AM fungi to manage the root-knot

nematode problem in agricultural crops. Though, several non-chemical management tactics like

fallow, flooding, changes in time of sowing / planting material, tillage practices, crop rotations, use

of antagonistic crop, trap crop/ cover crop, use of nematode free planting materials or seeds,

solarization, organic amendment and biological control are available. Recently efforts are directed

towards the use of microbes to minimize the plant parasitic nematode population and to make soil

more suppressive to nematode diseases. Working with microbial agent the candidate organism

should posses following characteristics in the nematode management. The microbes should be

Host specific

Parasitism is always lethal

Easily manipulated in laboratory

Can be mass produced

Easily disseminated with standard equipment


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Potential for establishment & recycling

Provides control for extended period

Not harmful to environment

Shelf-life of at least one year

Rhizospheres are complex environment where several microorganisms interact with each

other. Nematophagus or nematode destroying fungi are important component of rhizosphere and

they parasitizes the nematode/ egg/ female and use them as their source of growth and

development. On the basis of the infection to nematode these fungi are known as nematode

trapping fungi , endoparasitic fungi , egg and female parasitic fungi etc. Adhesive compounds are

secreted by nematode trapping fungi over the entire surface fungal trapping structure which helps

to dissolve the nematode cuticle. The major fungal anatagonists to phytonematodes are :

Arthobotrys amerospora, A. brochropaga, A. conoides, A. dactyloides, A. musiformis, A.

oligospora, A. pravicovia, A. robusta, A. superb, Catenaria anguileulae, auxillaris, C. vermicola,

Monacrosporium cionopagum, M. ellipsosporum, M. lysipagum, M. thaumasia, Hirsutella

heteroderae, H. rhossilensis, Nematoctonus concurrens, N. haptocladus, Drechmeria coniospora,

Harposporium anguillulae, H. subliforme, Catenaria auxialiaris, Dactylella candida, D.

oviparasitica, Nematopthora gynophila, Paecilomyces lilacinus, P. nostocoides, , Verticillium

chalamydosporium (Pochonia chlamydosporium), Verticillium balanoides V. lamellicola, V.

leptobactrum, V. suchlasporium, Trichodrma harzianum, T.virens, T. atroviride etc.

The association of AM fungi with roots brings several changes in the plants as these fungal

organism absorb nutrients which makes plants more healthy and induces resistance against

several plant diseases. The AMF colonize the root system and make a thick fungal mat around the

root therefore alter other pathogen to infest the colonized root system. These fungi may change

the physiology of the root system or compete with other organisms for root colonization. There are

several groups of fungi associated with plant root system but in agriculture it is the arbuscular

mycorrhizal fungi (AMF) of the Phylum Glomeromycota that is the most important. AMF actively

associated with a large number of plants except plant families of Brassicae and Chenopodiaceae.

Generally the AM fungus consists of two phases as one part of fungus i.e. mycelium is inside the

root and other part is distributed in soil to form the hyphal net, which absorbs the nutrients like

soluble phosphorus, iron, and provide these to plant for its health. The arbuscular mycorrhizal

fungi generally increase uptake of immobile phosphate ion and in return the AM fungi gets carbon

from the plants. The mycorrhiza and plant parasitic nematodes occupy root system and

mycorrhizae are useful to plants, whereas phytonematodes are detrimental to plant. Nowadays

mycorrhizal fungi have becomes a useful tool to manage nematode infestation in plants resulting

in an enhanced crop production and yield. Phytonematodes and arbuscular mycorrhizal fungi both

are associated with plant root for their food and space. The major interest in such an association is

to provide an increased plant resistance against phytonematodes. Symbiotic association of


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mycorrhizal fungi with plants provides a range of beneficial effects like enhanced micro and macro

nutrient availability provides resistance to plants against different biotic and abiotic factors and

makes the soil healthy.

Nowadays researcher are more inclined for organic farming due to adverse effect of

chemical nematicides on environment and human health. But in such farming system we have to

take a lot of precaution to maintain the rich population of useful organism in the soil to make soil

more suppressive to plant diseases. Normally the organic farming is recommended but due to low

yield, it is difficult to satisfy farmers for their product price. In developed nations farmers are getting

good price but in country like India farmers are hesitating to opt organic technology. CIMAP is

leading in this direction and trying to satisfy the farmers for such cultivation of medicinal and

aromatic plants and having great price for their organic products. The organic farming also affects

the mycorrhizal population and other pathogen population in soil.

Various types of bacteria are involved in decreasing the nematode population in soil. On

the basis of their mode of action these bacteria may be considered as obligate parasite,

opportunistic, rhizospheric, cry protein forming, endophytic and symbiotic bacteria as few are

parasite to nematode and others are indirectly involved to reduce the nematode infestation to

plants. Few bacteria like Bacillus spp. and Pseudomonas spp. are among the dominant

population in the root rhizosphere which antagonize the phytonematode population. Similarly

Pseudomonas spp. also exhibit nematode suppressive effect against variety of nematode species

through production of antibiotic, induction of systemic resistance. Several genera of other

rhizobacteria has shown the antagonistic activities against plant parasitic nematodes are

Actinomycetes, Agrobacterium, Arthobactor, Alcaligenes, Aureobacterium, Azotobacter,

Beijerinckia, Burkholderia, Chromobacterium, Clavibacter, Clostridium, Comamonas,

Corynebacterium, Curtobacterium, Desulforibtio, Enterobacter, Flavobacterium, Gluconobacter,

Hydrogenophaga, Klebsiella, Methylobacterium, Phyllobacterium, Phingobacterium, Rhizobium,

Serratia, Stenotrotrophomonas and Variovorax . The different ways by which rhizobacteria

antagonize the plant parasitic nematode populations are:

Disrupts the nematode-host recognition and thus regulate the nematode behavior.

They compete with nematode for nutrients for there living.

Rhizobacteria promote plant growth and therefore nematode could not attack the healthy

roots easily.

Antibiotics produced by the rhizobacteria directly or indirectly induce resistance and hence

reduce nematode population

Different microbes have been exploited in this lab to reduce the population of plant

parasitic nematodes below the economic threshold level and could play a significant role either

singly or can be integrated with other practices to develop integrated nematode management

practices (INMP). Studies conducted at CIMAP, Lucknow so far indicate that microbial agents may


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play a significant role in limiting plant parasitic nematode population. The results of the studies

carried out on major medicinal plants like Artemisia annua, Withania somnifera, Rauvolfia

serpentina, Bacopa monnieri and aromatic plants like Abelmoschus moschatus, Artemisia pallens,

Mentha arvensis, Rosa damascena, Lavandula officinalis and Pogostemon cablin (syn= patchouli)

have proven the efficacy of microbial agents (Paecilomyces lilacinus, Glomus aggregatum,

Trichoderma harzianum, Glomus fasciculatum, Glomus mosseae, Pseudomonas fluorescens etc.)

and organic farming too in the management of nematode and for sustainable growth and yield of

medicinal and aromatic plants.

SELECTED READINGS

1. Barbosa, P, Kirschik,L & Jones, E. (eds.) 1990. Multitrophic Level Interactions among microorganisms, plants, and insects. New York: John Wiley.

2. Bagyaraj, DJ; Manjunath, A. & Reddy, DDR. 1979. Interaction of vesicular arbuscular Mycorrhizae with root-knot nematode in tomato. Plant and Soil 51: 397-407.

3. Bird, AF, and Bird J. 1991. The Structure of Nematodes. 2nd edition. 71pp. San Diego: CA Academic Press.

4. Brown, RH and Kerry, BR. 1987. Principles and Practice of nematode control in crops. Academic Press New York, 447pp.

5. Davies, KG, Kerry, BR & Flynn, CA. 1988. Observations on the pathogenicity of Pasteuria penetrans, a parasite of root-knot nematodes. Annals of Applied Biology 112, 1491–1501.

6. Elsen, A, Gervacio, D, Swennen, R and Wacle D.De. 2008. AMF-induced Biocontrol against plant parasitic nematodes in Musa sp. : a systemic approach. Mycrrhiza 18: 251-256.

7. Gupta,A. & Pandey, R. 2009. Mycorrhiza: The saviour of plants from Phytonematodes in Microbes , Applications and effects (Edited by Dr. P. C. Trivedi, Professor Department of Botany, University Of Rajasthan , Jaipur) :143-157

8. Hallmann J, Quadt-Hallmann A, Miller WG, Sikora RA & Lindow SE 2001. Endophytic colonization of plants by the biocontrol agent Rhizobium etli G12 in relation to Meloidogyne incognita infection. Phytopathol 91: 415–422.

9. Kloepper JW, Rodriguez-Kábana R, McInroy JA & Young RW . 1992. Rhizosphere bacteria antagonistic to soybean cyst (Heterodera glycines) and root-knot (Meloidogyne incognita) nematodes: identification by fatty acid analysis and frequency of biocontrol activity. Plant Soil 139, 75–84.

10. Koshy, PK, Pandey,R & Eapen, SJ. 2005. Nematode Parasites of Spices, Condiments and Medicinal Plants in Plant Parasitic Nematodes in Subtropical and Tropical Agriculture 2

nd Edition (Eds. M. Luc, ORSTOM, France, Sikora, RA, University of Bonn, Germany,

J. Bridge, CABI, Bioscience, Egham, Surrey, U.K.) : 751-791.

11. Luc, M., Sikora, RA & Bridge.J.2005. Plant Parasitic Nematodes in Subtropical and Tropical Agriculture 2

nd, 871pp., CABI, Bioscience, Egham, Surrey, U.K.

12. Pandey, R. 1998. Phytopathological impact of root-knot nematode on some medicinal and aromatic plants - Journal of Medicinal And Aromatic Crop Sciences 20: 67-84.

13. Pandey, R. 2003. Mint Nematology- Current Status and Future Needs in Advances in Nematology (Eds. P.C.Trivedi Professor, Department of Botany, University Of Rajsthan, and Jaipur): 155-166.

14. Pandey R. 2005. Field application of bio-organics in the management of Meloidogyne incognita in Mentha arvensis. Nematologia Medit. 33 (1): 51-54.

15. Price, PW., Bouton, CE., Gross, P, McPheron, BA.Thompson, J.N., and Weis, A.E.1980.

Interactions among three trophic levels: influence of plants on interactions

between herbivores and natural enemies. Annual Review of Ecology and


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Systematics 11: 41–65.

16. Sikora, RA 1992. Management of the antagonistic potential in agricultural ecosystem for the biological control of plant parasitic nematodes. Ann. Rev. Phytopathol. 30: 245-270.

17. Sturz AV & Kimpinski J .2004. Endoroot bacteria derived from marigolds (Tagetes spp.) can decrease soil population densities of root-lesion nematodes in the potato root zone. Plant Soil 262: 241–249.

18. Tian BY, Yang JK, Lian LH, Wang CY & Zhang KQ .2007. Role of neutral protease from Brevibacillus laterosporus in pathogenesis of nematode. Appl Microbiol Biotechnol 74: 372–380.

19. Willamson, VM. 1998. Root knot nematode resistance genes in tomato and their potential for future use. Annual review of Phytopathology 36: 277-293.

20. Whitehead, AG. 1998. Plant Nematode control. CAB International Wallingford, U.K. 384pp.


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Biological Control of Frost Injury: Role of Ice Nucleating Bacteria

S.C. Saxena Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

The science of plant pathology is largely a study of the mechanisms, quantification, and

alleviation of plant stresses due to biological agents. Of obvious importance are the stresses to

plants directly caused by various plant pathogenic fungi, bacteria, viruses, nematodes, insects,

etc. In such cases, plant stress is due either to direct damage to plant tissue or to an alteration in

normal plant metabolism. Some biological agents, such as the fungi that form mycorrhizae with

plant roots, may even reduce plant stress in certain situations and increase stress in others.

Plants may also be stressed directly and indirectly by various physical factors such as high

or low temperatures or air pollutants. Physical stresses such as temperature or air pollutants may

also influence the subsequent damage of plants incited by certain plant pathogens. Root infecting

plant pathogens, can make plants more susceptible to damage due to high temperatures or

drought.

Many more subtle interactions between microorganisms and plants have also been

reported. Bacteria living on the surfaces of healthy leaves and roots have been reported to

increase plant growth, possibly by production of one or more plant growth regulators. Conversely,

some bacteria isolated from root surfaces have been shown to be detrimental to root and plant

growth.

Frost injury is a serious abiotic disease of plants. Losses in plant production in the United

States due to frost injury are estimated at over one billion dollars yearly. Frost injury has been

described as one of the main limiting factors to crop production in many locations in the temperate

zone. Little attention has been paid to the mechanism of frost injury to frost-sensitive agricultural

plants that are damaged at temperatures warmer than -50C. Frost injury was considered an

unavoidable result of physical stress (low temperatures) to these plants.

Some plant frost recently has been shown to involve an interaction of certain leaf surface

bacterial as well as low temperature stress. Some bacteria cause the frost-sensitive plants on

which they reside to become more susceptible to freezing damage by initiating the formation of ice

that is required for frost injury.

In this talk, the importance of some epiphytic bacterial that initiate ice formation on plants

(ice nucleation active bacteria) are discussed in reference to their significance to the frost

sensitivity of many plants, and to initiation of disease. Some aspects of plant physiology and

physics relevant to frost damage in frost-sensitive plants are discussed to elucidate further the

unique role that ice although indirectly, the world’s most destructive abiotic disease.

Bacterial Ice Nucleation in Plant Disease

Many pathogenic strains of P. syringae have been reported to survive in large numbers as

epiphytes on a variety of symptomless host plants, including stone fruits, olive, bean and soybean.


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Since infection by P. syringae often occurs after injury to a host plant, this observation may attest

to the ubiquitous presence of this bacterium as an epiphyte.

In fact, frost injury has been reported as a predisposing factor for infection of some plants

by P. syringae. It has been reported that pear blossoms supercooled to approximately –20C. If

flowers were sprayed with a bacterial suspension after freezing, infection by P. syringae pv.

syringae was severe, whereas infection of inoculated unfrozen flowers was minimal. P. syringae

pv. syringae was found to occur in large numbers on flowers from branches from field sources but

was not found on greenhouse-grown tree.

Therefore, frozen field-grown flowers which were sprayed with water after freezing

sustained severe infection by P. syringae, whereas greenhouse-grown flowers did not. Frost injury

has also been implicated in outbreaks of bacterial blight of pea (Pisum sativum L.) incited by

P. syringae pisi in South Africa.

Freezing injury has also found to aid in the development of bacterial canker of poplar

(Poplar spp.) caused by P. syringae pv. syringae, and an unidentified pathogen of barley. A strong

relationship between frost injury to apricot (Prunus armenica L.) and development of bacterial

canker incited by P. syringae pv. Syringae was recorded.

The ice nucleation activity of P. syringae pv. syringae strains was well correlated with

development of cankers on inoculated peach seedlings frozen at –100C. The scientists suggested

that ice nucleation activity by P. syringae pv. syringae was important in the development of

bacterial canker of peach. The use of an ice nucleation-deficient mutant of P. syringae in this

study, however, would help clarify the role of ice nucleation in canker development.

Mechanism of Plant Frost Injury

Frost-sensitive plants are distinguished from frost-hardy plants by their relative inability to

tolerate ice formation within their tissues. Examples of frost-sensitive plants tissues include

herbaceous annual plants, flowers of deciduous fruit trees, fruit of many plant species, and shoots

and stems of certain forest trees such as Eucalyptus. Ice former in or on frost-sensitive plants

spreads rapidly both intercellular and intracellularly, causing mechanical disruption of cell

membranes. This disruption is usually manifested as a flaccidity and/or discoloration upon

rewarming of the plant. Thus, most frost-sensitive plants have no significant mechanisms of frost

tolerance and must avoid ice formation to avoid frost injury.

Two general types of ice nuclei exist: heterogeneous and homogeneous. Homogeneous

ice nuclei are of primary importance at low temperatures whereas hetrogeneous nuclei are more

importance at temperatures approaching 00C. Small volumes of pure water can be supercooled to

approximately -400C before the spontaneous homogeneous catalysis of ice formation occurs.

Even relatively large quantities of water readily supercool to -100C to -200C.

Catalysis of ice formation in water involves a transient ordering of water molecules into a

lattice resembling ice. The number of water molecules that must be ordered to trigger macroscopic

ice formation in super-cooled water is governed by thermodynamic and geometric considerations


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and decreases with decreasing temperature. At very low temperatures (approaching –400C),

random grouping of water molecules can efficiently trigger homogeneous ice formation within short

time intervals.

At warmer temperatures, nonaqueous catalysts for ice formation known as heterogeneous

ice nuclei are required for the water-ice phase transition. The mechanism of ice nucleation of all

heterogeneous ice nuclei is due to ordering of water molecules into an ice-like lattice, perhaps in

the case of inorganic salts, by aggregation of water molecules onto the face of fractured crystals

with lattice structures similar to ice. The efficiency of heterogeneous ice nuclei presumably

increases with increasing numbers of water molecules oriented in a rigid ice-like array.

Non-biological Sources of Heterogeneous Ice Nuclei

The most common and the most thoroughly studied source of heterogeneous ice nuclei are

mineral particles, particularly silver iodide. These mineral particles efficiently nucleate ice only at

temperatures lower than -8°C to -15°C. Most organic and inorganic materials such as dust

particles nucleate ice only at temperatures lower than -10°C to -15°C. Dust particles, particularly

certain mineral clays have long been considered as primary sources of ice nuclei. Mineral particles

of meteoric origin (are also considered abundant atmospheric ice nuclei. These minerals are active

as ice nuclei primarily at temperature colder than –150C, therefore are quite unlikely to account for

ice nucleation at relatively warm subfreezing temperatures.

Kaolinite is among the most active minerals ice nucleus sources, but it is active in ice

nucleation only at temperatures below about -9°C. Silver iodide, used in weather modification

studies as a cloud seeding agent, is active in ice nucleation only at temperatures warmer than -

8°C. Its abundance in nature is also very low.

Crystals of a number of inorganic compounds, however, are ice nuclei at temperature

warmer than -10°C. Crystals of several organic compounds also have ice-nucleation activity,

including steroids, amino acids, proteins, terpenes, metaldehyde, phenazine, and others. Although

these organic compounds are active in ice nucleation at relatively warm temperatures (warmer

than -5°C), they are active as ice nuclei only in a crystalline form. When solubilized, these

compounds lose ice nucleation activity .The natural occurrence of the crystalline form of these

organic compounds .is likely to be small.

ICE Nucleation on Plant Surfaces

• The supercooling of plant tissues is limited by the heterogeneous ice nucleus that is active

at the warmest temperature. Therefore, the number and activity of heterogeneous ice

nuclei in or on plants can be determined by analysis of the supercooling points of plant

tissue.

• The ability of many frost-sensitive plants to supercool has been recognized for some time.

It has been shown that flowers of small fruit trees supercool to only -2°C before ice

formation occurs. Extensive supercooling has been reported for lemon, grapefruit, and

other Citrus species. Wheat leaves have been reported to supercool to -4.5°C to -5.0°C.


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Several recent reports also indicate variability in the degree of supercooling, which ranged

from -2°C to -14°C for a large number of even green different plant species.

Bacterial Ice Nuclei

• Recent research has focused on the search for biological sources of ice nuclei. The

concentration of ice nuclei in the atmosphere at a given location was observed to increase

with increasing organic matter content of the soil. Decaying vegetation is a source of

abundant ice nuclei. The bacterium P. syringae, associated with decaying leaf material,

was shown to be an active ice nucleating agent.

• Recently, three species of bacteria commonly only found as epiphytes on leaf surfaces

have been shown to be catalysts for Ice formation. Many pathovars of P. syringae are

active in ice nucleation and are generally the most common ice nucleation active bacteria

found on plants in the United States. Certain strains of both E. herbicola, and P.

fluorescens are also active in ice nucleation.

• Other scientists have reported that certain strains of other Pseudomonas and stewartii are

active in ice nucleation, but these reports have not yet been verified. Approximately 50% of

the many pathovars of P. syringae examined, including P. syringae pv. coronafaciens, P.

syringae pv. pisi, and P. syringae pv. lachrymans are active in ice nucleation.

• The strains of P. syringae and E. herbicola studied to date are the most active naturally

occurring ice nuclei. These bacteria catalyze ice formation at temperatures as warm as -

1°C. Not every cell of P. syringae, E. herbicola, or P. fluorescens is active as an ice

nucleus at a given time. The fraction of cells that are active as ice nuclei increases rapidly

with decreasing temperatures below -10C.

• The strains of P. syringae and E. herbicola studied to date are the most active naturally

occurring ice nuclei yet discovered. These bacteria catalyze ice formation at temperatures

as warm as -1°C. Not every cell of P. syringae, E. herbicola, or P. fluorescens is active as

an ice nucleus at a given time. The fraction of cells that are active as ice nuclei increases

rapidly with decreasing temperatures below -10C.

Measurement of Bacterial Ice Nuclei

The study of the ecological role of bacterial ice nuclei has been facilitated by the

development of a number of rapid quantitative assays for their presence and qualitative activity.

Measurements of the cumulative number of ice nuclei active above a given temperature are

reported by several scientists A droplet freezing assay developed, has been the basis for most

measurements of bacterial ice nuclei which yields an estimate of the number of freezing nuclei,

defined as those heterogeneous ice nuclei that are active when suspended in water.

A modification of this method in which aqueous suspensions of bacteria are placed in calibrated

capillary tubes has been reported to increase slightly the accuracy of determination of ice

nucleation temperatures. The activity of bacteria as contact ice nuclei, in which dry bacterial cells

contact and nucleate supercooled water droplets suspended in an isothermal cloud chamber, .has


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also been reported.

Ice Nucleation Active Bacteria on Plants

Most field-grown plants are colonized by large epiphytic populations of one or more

species of ice nucleation active bacteria. Nearly all of 95 species of agricultural and native plants

sampled from several locations in North America, with the exception of conifers and smooth

leaved crucifers, harbored detectable populations of epiphytic ice nucleation active bacteria. Ice

nucleation active bacteria on plants have also recently been reported from Israel and Japan.

The numbers of ice nucleation active bacteria on plant surfaces vary among species as

well as temporally on a given species. The maximum populations of ice nucleation active bacteria

ranged from approximately 100 cells/g fresh weight of valencia and navel orange (Citrus sp.) leaf

tissue to over 107 cells/g fresh weight on leaves of English walnut or almond.

Many more plant pathologists have studied leaf surface populations of phytopathogenic

bacteria or their antagonists., including species now known to nucleate ice. Populations of P.

Syringae. and E. herbicola have been reported on a variety of plants throughout the world and are

ubiquitous epiphytes on nearly all plants studied. The occurrence of ice nucleation activity among

strains of E. herbicola is as yet largely unknown, but is probably low.

However, the observation that at least half of the pathovars of P. syringae are active as ice

nuclei indicates that ice nucleation active bacteria have a worldwide distribution. Similarly, strains

of P. fluorescens are common sol! and water Inhabitants. Even if a low percentage of P.

fluorescens strains are active in ice nucleation, this species may also be an important source of ice

nuclei.

Bacterial Ice Nucleation and Frost Injury

A single ice nucleus is currently thought to be sufficient to initiate ice formation and

subsequent frost injury to an entire leaf, fruit, flower, or even groups of leaves or flowers,

depending on the degree of restriction of ice propagation within a plant. Since frost-sensitive plants

must avoid ice formation to avoid frost damage, frost injury to these plants might best be

considered a quantal response – either a plant part escapes ice formation or it does not.

The extent of frost damage at a given temperature increases with increasing populations of ice

nucleation active bacteria on that plant. Frost injury at a given temperature is more directly related

to the numbers of actual bacterial ice nuclei on the plant at the time of freezing than to the

population of ice nucleation active bacteria.

Current Practices for Management of Plant Frost Injury

• involve physical warming of plant tissue to at least 00C to avoid internal ice

formation or

• By planting frost-sensitive plants in sites which do not have a history of cold

temperatures.

• Physical methods of frost prevention

• use of stationary wind machines


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• helicopters to mix the cold layer of air nearest the ground with warmer air aloft

• Heaters have been employed to heat the air in the vicinity of plants in need of

protection.

• Radiational cooling of plants

• Radiative heat losses can be reduced by the application of artificially generated

fogs or foam-like insulation to cover plants

• Application of water directly to plant parts during periods of freezing temperatures.

Application of water directly to plant parts during periods of freezing temperatures.

Although ice may from during such a process, it is limited to the exterior of the plant. Frost damage

does not result so long as additional water is applied to ice-covered plant parts during the entire

period the air temperature is below 00C. The latent heat of fusion, released when water freezes to

form ice, warms the ice-water mixture on leaves to 00C. This mixture will remain at 00C as long as

water is continuously available to freeze on plant surface. Since all plants contain dissolved salts

and other soluble components, the freezing point of the plant tissue is slightly lower than 00C. Ice

held at 00C on the surface of the plant will not penetrate and disrupt plant tissues.

Bactericides

One new alternative method of frost management has included the use of commercially

available bactericides to reduce populations of ice nucleation active bacteria on plants. Large

(100- to l000-fold) reductions in populations of epiphytic ice nucleation active bacterial are

observed following protectant bactericide applications when compared with untreated plants. The

numbers of ice nuclei on bactericide-treated plants was also significantly lower than on untreated

plants, thereby reducing the chances of frost injury to a given plant part at temperatures above -

5°C.

Antagonistic Bacteria

Only about 0.1% to 10.0% of the total bacteria found on plant surfaces are active as ice

nuclei and are therefore involved directly in frost injury. Competition or other form(s) of antagonism

between these and other epiphytic bacteria and other microorganisms on leaf surfaces appears

likely based on studies of other ecological niches.

The degree of nature competition among epiphytic microorganisms is insufficient to prohibit

buildup of significant of epiphytic ice nucleation active bacteria on most plants. However, this

natural antagonism may be augmented by altering the leaf surface microbial ecology so as to favor

increased populations of non-ice nucleation active bacteria competitors. These bacterial

competitors may then occupy a niche on the plant that might otherwise be colonized by ice

nucleation active bacteria.

Integrated Management

Integrated management of fire blight and frost injury of pear have recently been reported.

An antagonistic non-ice nucleation active bacterium applied at 10% bloom to pear trees colonized

pear flowers and leaves for over three months and reduced significantly the epiphytic populations


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of P. syringae and Erwinia amylovora.

The incidence of both frost injury, and, later, fire Blight, was reduced significantly compared

to untreated trees. The control of frost injury and fire blight from a single application of antagonistic

bacteria was nearly as good as from weekly applications of a mixture of streptomycin and

oxytetracycline or cupric hydroxide.

Frost Injury with Non-Nucleation Active Bacteria

Control of frost injury with non-nucleation active bacteria is a good model system with

which to study biological control processes for a number of Reasons:

1. Frost injury is an important, worldwide problem;

2. The target Microorganism are well known and can be well quantified based on their

Phenotype of ice nucleation activity;

3. Subtle microbial interactions on leaves may be expressed and therefore quantified

as altered ice nucleation activity of bacteria on leaves; and,

4. Even in the absence of frost injury, information gained on the ecology and control of

ice nucleation active pathovars of p. syringae could be exploited to achieve

management of the disease initiated by these and other bacteria by reduction of

epiphytic inoculums sources on host plants.

Ice Nucleation Inhibitors

Chemicals that quickly inactivate the ice nucleus associated with ice nucleation active

bacteria without necessarily killing bacterial cells have been termed “bacterial ice nucleation

inhibitors”. Laboratory tests have shown that the ice nucleation site associated with ice nucleation

active bacteria is sensitive to various physical and chemical stresses such as extremes of pH,

specific heavy metal ions in a soluble state (including copper and zinc), and certain cationic

detergents (unlike most commercial anionic surfactants used in agriculture).


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Characterization of Pathogen Population and Resistance Management: A Case Study of Rice Blast Pathosystem

J. Kumar


Rice (Oryza sativa L.) is a staple food for over 2 billion people, providing 20% of human

food calories. “Blast”, caused by the heterothallic ascomycete Magnaporthe grisea (Hebert) Barr.

(anamorphe : Pyricularia grisea Sacc.) is the most important disease of rice and can cause severe

losses in most rice-growing environments . Although only known to reproduce asexually in nature,

the pathogen is notorious for its pathotypic diversity. Disease resistant rice cultivars are the

preferred means of blast management, considering that most rice farmers are poor and that

effective fungicides are quite costly. However, resistance in such cultivars is frequently short-lived.

Typically, a variety released as blast-resistant shows signs of susceptibility after only very few

seasons of cultivation in blast-prone environments.

Resistance “breakdown” is usually ascribed to extreme diversity and/or virulence variability in

the pathogen. In the case of extreme diversity, it has been proposed that much of the observed

resistance breakdown resulted from simple “escape” due to inadequate challenge in screening

nurseries. That is, either because conditions are not suitable for disease development, or if some

pathotypes are so rare as to not encounter a compatible line, lines may be incorrectly interpreted to

be `resistant'. As a breeding line is multiplied for release and eventually planted over large areas,

chances increase for encounter between compatible pathotypes and the new variety. With a large

host population the previously rare pathotype reproduces rapidly, and the observed `new'

susceptibility of the cultivar is interpreted as a resistance `breakdown'.

There is some evidence for escape being an important phenomenon in the lack of durability of

blast resistance. By conducting a blast resistance breeding program in a site with a highly diverse

pathogen population and an environment that supports continuous blast epidemics, durably resistant

cultivars could be developed. One such cultivar, Oryzica Llanos 5, has been grown continuously over

thousands of hectares for over 15 seasons in a severely blast-prone environment. Furthermore, it

has been evaluated in a number of countries across the world and found to be highly resistant in all

sites.

The question of pathotypic variation has long been controversial. At one extreme the

pathogen was described as hypervariable, with the capacity to generate a seemingly endless array

of new pathotypes from a single asexual spore. Thus, varieties evaluated for resistance to a single

pathotype would be exposed to an infinite range of pathogenic variation once released into the

field. A variety stood little chance of surviving under the onslaught of such variation, and the

reasonable conclusion was that race-specific resistance to the pathogen could not yield durable

resistance. This led to a major effort to develop race non-specific, or partial, resistance. At the

other extreme, the pathogen was described as completely stable, with no new races generated


- 146 -

even after years of culture in the laboratory. It is noteworthy that the proponents of hypervariability

worked with isolates from Asia (the center of origin of rice), recently recovered from the field, while

proponents of stability worked largely with isolates from the US (where rice was introduced only a

few hundred years earlier) and that had been in culture for a number of years.

Blast populations are very diverse, regardless of the mechanisms (genetic or otherwise)

that generated the diversity, and the design of most breeding programs is such that a blast-

resistant variety is simply not exposed to pathogenic variants that it would likely encounter under

production conditions. In other words, real-world rice varieties would be exposed to populations of

the pathogen, not just one or two races.

Virulence variation in pathogen populations

Plant pathologists and plant breeders have long understood the importance of pathogen

variation to the effectiveness and durability of host resistance. Pathogen genotypes can interact

with specific host genotypes leading to the "breakdown" of resistance within very short periods of

time. Detection of pathogen variation has traditionally relied upon the identification of virulence

variation (races) in the pathogen population by inoculating a sample of pathogen isolates on a

series of hosts with defined resistance genes (differentials) and observing the resulting compatible

or incompatible disease phenotype. This approach to monitoring pathogen populations has been

tremendously valuable in the development and deployment of host resistance, and has provided

important insights into the evolution of pathogen populations in response to selection by host

resistance genes. Pathotype monitoring is still used extensively in many pathosystems today and

continues to provide timely information about the structure of pathogen populations that is relevant

to breeding programs and resistance deployment.

Limitations on the use of virulence phenotype

Despite the obvious value of pathotype data, the use of virulence phenotypes to assess

genetic variation in plant pathogens has several important limitations. Host differential lines used in

virulence assays are often poorly defined genetically. A common set of differentials must be used

among labs to obtain comparable data, and assays are subject to environmental variation. A more

important limitation is that virulence variation in plant pathogens is almost always determined in

terms of virulence phenotype rather than genotype, which means that frequencies of virulence

genes cannot be estimated from these assays. This lack of genetic information coupled with the

fact that virulence phenotypes are subject to strong selection by the host limits the value of

virulence markers as population genetics tools.

Molecular markers in pathogen population analysis

Lately, plant pathologists interested in genetic variation in pathogen populations have

adopted the use of molecular markers as population genetics tools. Motivating this shift has been

the availability of a myriad of molecular techniques which makes the quantification of genetic

variation a relatively straightforward endeavor. Molecular markers such as allozymes , restriction

fragment length polymorphisms (RFLP) and random amplified polymorphic DNA (RAPD) have


- 147 -

been extensively used to characterize pathogen populations. More recently, amplified fragment

length polymorphisms (AFLP) have proven to be highly polymorphic and robust markers and will

likely be used extensively with plant pathogenic fungi in the future. In contrast to virulence and

fungicide resistance markers, molecular markers are presumed to be selectively neutral and

therefore may be used to study evolutionary processes in addition to selection.

The discovery of a neutral repetitive DNA sequence, MGR (for Magnaporthe grisea repeat)

in the rice blast pathogen in the late 1980s provided a means of analyzing populations

independently of the pathogenicity of the constituent isolates. The similarity of the MGR

"fingerprints" generated by analyzing the DNA of different isolates permitted an estimate of their

relatedness. Initial analysis of archival US P. grisea isolates revealed a direct relationship between

fingerprint type (subsequently referred to as lineages) and pathogenic races . Application of this

analytical tool to the Santa Rosa population yielded a less direct, but intriguing, relationship

between lineage and race: Sets of closely related races fall within a single lineage and the race

constitution of lineages differed. Furthermore, in what had been described as an extremely race-

diverse population, all isolates could be grouped into only six lineages. This led to the suggestion

that rice breeding could focus on selecting for cultivars that combined resistance that was effective

against the virulence spectrum of all lineages in a target population.

Lineage exclusion

This breeding approach, referred to as "lineage exclusion", assumes that P. grisea

populations are comprised of a few number of discrete lineages and that these lineages have

different and stable virulence spectra. These assumptions were tested in two populations from

blast resistance screening nurseries in the Philippines. It was found that , as in Colombia, there

were relatively few lineages comprising the populations . Analysis of lineage virulence spectra (i.e.,

the virulence of isolates on sets of isolates with known and different resistance) revealed that they

were indeed different. "Composite pathotypes" could be created for a lineage by considering any

compatibility within a lineage as reflecting the virulence capacity of that lineage. Comparing the

composite pathotypes of all the lineages of a population could predict what combination of

resistance would be effective across the entire population. In the case of the Philippines, a

combination of resistance genes Pi-1 and Pi Z5 (Pi-2) should yield resistance effective across all

lineages.

A similar analysis in Santa Rosa (Colombia) also predicted that the same two genes should

yield broad-spectrum resistance. This was tested by crossing two sources of resistance and then

evaluating the progeny in the field (exposing them to a diverse, well-characterized population) and

in the greenhouse (exposing them to isolates representing the full virulence spectrum in all

lineages in the population). As expected, progeny resulted with full spectrum resistance in both

greenhouse and field evaluations. Based on this positive result, parents in crosses for blast

resistance in Santa Rosa have been selected to combine complementary resistance. This has

yielded an significant increase in the efficiency of the breeding programs.


- 148 -

How effective can lineage exclusion be as a breeding tool for obtaining durable blast

resistance world-wide? A few critical issues suggest that with present technology, all areas may

not be suitable for its adoption. The situations in the Philippines and Santa Rosa may be

somewhat atypical in that these populations are from areas where modern varieties have been

grown and, because of a bottleneck effect of earlier deployed blast resistance, the pathogen

population may be much simpler than those populations in other rice-growing regions. i.e. if

populations are very complex it could be practically impossible to characterize the virulence

spectra of all lineages. Furthermore, for lineage exclusion to yield durable resistance, lineages

should be genetically isolated from one another so that virulence genes cannot be exchanged

among lineages.

A population analysis of P. grisea from a traditional rice-growing area of northeast Thailand

revealed a very complex population: 49 lineages were identified from 527 isolates, and most were

represented by only one or a few isolates . No obvious relationships between pathotype and

lineage was discerned within these samples using either lines near-isogenic for resistance genes

or cultivars with known resistance. Very high lineage diversity was also observed in the Indian

Himalayas and very high pathotypic diversity was observed in the Himalayan Kingdom of Bhutan,

although the corresponding lineage data are sketchy. It would be impossible to determine the

virulence spectrum of lineages comprising these populations. The problems however

notwithstanding, the analysis of the NE Thailand population revealed the same complementary

effectiveness of resistance genes Pi 1 and Pi z5.

An important assumption of the lineage exclusion approach is that there is no gene flow

across or genetic recombination among lineages. Several lines of evidence suggest that this may

not be the case in some areas. Reports of sexually fertile field isolates from India , China , and

Thailand indicate that the capacity for sexual recombination exists in nature. Population structure

and dynamics of Indian Himalayan populations are consistent with sexual recombination having

influenced populations there . There is also the possibility that horizontal flow of genes, including

those mediating resistance to entire lineages, can occur across lineages via non-sexual, or

parasexual, means .

Despite indications that there may be very large areas over which a population analysis-

based lineage exclusion breeding strategies may not be appropriate, there is ample evidence that

population analyses can yield valuable dividends. First, in most cases examination of the virulence

spectra of the most common lineages should indicate to breeders which crosses are unlikely to

yield durable blast resistance, thus increasing their efficiency. Second, the repeated conclusion

that the gene combination Pi 1 and Pi z5 is effective across very different populations suggests

there is something fundamentally limiting to P. grisea carrying compatibility to both genes

simultaneously. As more blast resistance genes are identified and placed in near-isogenic

backgrounds population analyses will enable us to identify other broadly effective gene

combinations. Finally, there are large and important rice growing areas where P. grisea


- 149 -

populations are relatively simple. These may be where rice has only recently been introduced, or

where very large areas have been planted to a few varieties carrying several major resistance

genes. Breeding strategies for these areas should be adjusted accordingly.

REFERENCES

1. Correa-Victoria, F.J., Zeigler, R.S. 1995. Stability of partial and complete resistance in Rice to Pyricularia grisea under rainfed upland conditions in eastern Colombia. Phytopathology 85:977-982.

2. Correa-Victoria, F.J., and Zeigler, R.S. 1993. Pathogenic variability in Pyricularia grisea at a rice blast "hot spot" breeding site in eastern Columbia. Plant Disease 77:1029-1035.

3. Kumar, J., Nelson, R. J., and Zeigler R. S., 1996. Population structure of Magnaporthe grisea in the traditional Himalayan rice system. In: Rice Genetics III. IRRI-CABI, Los Banos, Philippines, pp 963- 969.

4. Kumar, J., Nelson, R.J., and Zeigler, R.S. 1999. Population structure and dynamics of Magnaporthe grisea in the Indian Himalayas. Genetics 152:971-984.

5. Kumar, J. and Zeigler, R.S. 2000.Genetic diversity and evidence for recombination in

6. Himalayan populations of Magnaporthe grisea. In: Proceedings of the International

7. Conference on Integrated Plant Disease Management for Sustainable Agriculture. Vol. I.

8. Indian Phytopathology Society, IARI New Delhi., pp. 127-134.

9. Leung, H., R. J. Nelson, and J. E. Leach. 1993. Population structure of plant pathogenic fungi and bacteria. Advances in Plant Pathology 10:157-205.

10. Milgroom, M. G., and W. E. Fry. 1997. Contributions of population genetics to plant disease epidemiology and management. Advances in Botanical Research 24:1-30.

11. Zeigler, R.S. 1998. Recombination in Magnaprthe grisea. Annual Review of Phytopathology 36:249-276.

12. Zeigler, R.S., Scott, R.P., Leung, H., Bordeos, A.A., Kumar, J., and Nelson, R.J. 1997. Evidence of parasexual exchange of DNA in the rice blast fungus challenges its exclusive clonality. Phytopathology 87:284-294.

13. Zeigler, R.S., Tohme, J., Nelson, R. J., Levy, M., Correa, F. J. 1994. Lineage exclusion: A proposal for linking blast population analysis to resistance breeding. pp. 267-292 in Rice Blast Disease, R. S. Zeigler, P.S. Teng, S. A. Leong (eds.) Commonwealth Agricultural Bureaux, Walllingford, UK.


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Visit to Automatic Weather Station and Meteorological Observatory at CRC

H.S. Kushwaha

Department of Soil Science, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Introduction

Since the meteorological instruments in the meteorological observatories are exposed

over the short cut grass, apparently the values of some of the important weather variables

especially the air temperature, relative humidity, leaf wetness and the wind in particular may

differ significantly from those observed in a cropped field. The major meteorological instruments

available at meteorological observatory included Stevension screen to house maximum

thermometer, minimum thermometer, dry bulb thermometer and wet bulb thermometer, three soil

thermometers each at 5, 10 and 20 cm soil depth, USWB Class A open Pan evaporimeter,

Ordinary & self recording rain gauges, Anemometer, Wind vane, Bright Sunshine recorder, dew

gauge etc. The data is recorded daily twice a day at 0712 hrs and at 1412 hrs at Pantnagar by

IMD trained meteorological observers and record is maintained in pocket registers supplied by

IMD. However, the validity of such weather data recorded at meteorological observatory at a

location from a field experiment will decrease with the distance from the meteorological

observatory. Keeping in view this constraint, for disease-weather relation studies it is,

recommended & advised to monitor these important weather variables over and within the crops

under natural field conditions. These fields have variability in terms of crops their type and

stage, soil moisture, ground water table, tillage operations for soil manipulation etc. as compared

with the meteorological observatory field. Also detailed and reliable weather information is also not

available in many locations in the country due to non-availabilty of meteorological observatories.

For this purpose, a Scientific Automatic Weather Station (AWS) attached with micrologger and

Computer will be very useful for recording of weather parameters within and over the crops

accurately and then correlate them with crop observations for understanding the real crop -

weather relationships in general and disease - weather relationships in particular for major crops

of the area. There is a close relationship between crop diseases and weather variables and,

therefore, under prevailing weather conditions, the incidence of several diseases may occur in an

area and the application of chemicals in these crops will depend on the intensity and durability of

the weather conditions prevailing at particular & sensitive crop stage. The details of observations

are discussed under following heads.

A. Meteorological observatory :

A plain area of 55 m (N-W) x 36 m (E-W) size with short cut grasses free from all

obstacles including highway, high building, big trees, canals, rivers and wild animals provides a

good exposure for installing all the meteorological instruments in the observatory. If a person

stands at the gate facing the observatory plot, he will find the tall instruments in the back row and

shorter instruments in the front rows. In general the instruments are separated at a distance of 9 m


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from each within rows of 12 m apart Fig.1.). All observations are taken manually by

meteorological observer daily twice a day.

The method of measurement of the important meteorological variables :

1). Maximum and Minimum Temperatures:

The maximum and minimum air temperatures (oC) are measured by maximum and

minimum thermometers, respectively. They are housed in a single Stevenson in approximate

horizontal position at about 4 feet height from the ground. The screen is erected on 4 wooden

posts supplied with the screen with its door opening to the north and the bottom at 4 feet

approximately above the ground level.

2). Relative Humidity:

The relative humidity (%) is measured indirectly by the readings of dry and wet bulb

temperatures. The dry and wet bulb temperatures are measured by Dry and wet bulb

thermometers which are placed in the above Stevenson screen perfectly in the vertical positions.

The height of the bulbs of dry and wet thermometers should be from 4' 3" to 4' 6" above the

ground, respectively for correct measurements. From the readings of dry and wet bulb

temperatures the relative humidity is computed using Hygrometric Tables prepared by India

Meteorological Department (IMD), Pune, based on the values of Atmospheric Pressure of the

observatory locations throughout the Country. At Pantnagar the Hygrometric Table of 1000 mb is

used.

3). Soil Temperature:

The soil temperatures (oC) in the observatory are measured by specially designed Soil

Thermometers at 5, 10 and 15 cm soil depths. The plot where these thermometers are exposed

should not receive any shadow from the neighboring instruments or objects. The bulbs should be

at a vertical depth of 5 cm, 10 cm and 20 cm below the soil surface and the slant of the stem of the

thermometer should be towards north, i.e. the observer should be able to read the instruments by

sitting to the south of the instruments.

4). Rainfall:

The rainfall is measured by Raingauge. The ordinary Raingauge is erected on a masonry

or concrete foundation of 3' x 3' x 3' size and sunk into the ground. Into this foundation the base of

the gauge is cemented so that the rim of the Raingauge is exactly one foot above the ground level

and 10" above the concrete structure, i.e. the concrete structure will project 2" above the ground

surface. While getting the gauge, great care is taken to ensure that the rim is perfectly level.

However, the continuous recording of rainfall in the observatory is done by Self Recording Rain

Gauge on Charts.

5). Bright Sunshine Hours:

The recording of the number of bright sunshine hours (hrs) is done by Campbell Stoke’s

type Sunshine Recorder. This instrument is exposed on the terrace of the roof or on a pillar in the

'open' where the horizon is clearly visible between North - East and South - East on the Eastern


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side and between North - West and South - West on the Western side. The instrument should be

placed on a solid masonry pillar of any suitable height of 5' or 10' above ground depending upon

the exposure on eastern and western sides and rigidly fixed to it after proper adjustment is made.

The number of burns on the sunshine cards are counted to compute the duration of bright

sunshine hours (hrs) in a day on daily basis. However, no burning on cards takes place on cloudy

days.

6). Solar Radiation:

The quantity and intensity of solar radiation is measured by Pyranometer. This instrument

is placed in the same way as the sunshine recorder. The output in terms of solar radiation is

expressed in W m-2 or Cal.cm-2 day-1 units.

7). Wind Speed and Wind Direction:

Wind speed (km hr-1) is measured by Anemometer while its direction (in terms of Compass

points) is measured by Wind vane. These wind instruments are erected at a height of 10 feet from

the ground on wooden posts. The site for these instruments must be as open as possible and

there must not be any object loftier than the instrument for a long distance (as far as possible)

around. Long trees and building in the neighborhood are always objectionable. Even if there are

not lofty enough to screen the instruments, they serve to cause eddies or swirls which act on the

wind vane from a direction different from that of a general air current in the neighborhood.

Such obstructions do not also allow winds from all directions to strike the anemometer cups with

equal force. The standard exposure of wind instruments over open level ground in the observatory

plot should be 10 ft. above the ground. The distance between the wind instruments and any

obstruction should be at least 10 times the height of the obstruction.

8). Dew:

Dew (mm) is measured by Dew Gauges which are exposed at four heights on a stand and

the appearance of dew drops is compared with the standard photographs to quantify the dew in

terms of mm of dew fall on daily basis.

9). Recording Instruments:

i). Air Temperature:

The continuous recording of air temperature (oC) is done by the Thermograph or Thermo-

hygrograph. They are placed in the observatory area inside the double Stevenson screen. In the

same screen, a standard thermometer is also placed for comparison with its bulb at the level of the

thermal element and at a horizontal distance of about 5" from it.

ii). Relative Humidity:

The continuous recording of the relative humidity (%) of free air in the observatory is done

by Hair Hygrograph or Thermo-hygrograph. They are exposed in the observatory in the same

above double Stevenson screen. The Stevenson screen should be located in a place where the

surrounding air is not polluted by excessive smoke or dust particles or is surcharged with brine or

oil vapour, since these instruments have a deleterious effect upon the hygroscopic properties of


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the hair.

B. Automatic weather station (AWS) :

A Campbell Scientific Automatic Weather Station has been designed and developed to a

very high standard for reliable measurement and recording of wide range of important

micrometeorological variables in and above the crops The station is soundly engineered and

based Campbell,s proven 21X micrologger whose comprehensive specification enables the user

to undertake virtually any monitoring task F.g.2.). The main and important features of the system

are described as below ::

1. Wide range of sensors : A maximum of 20 sensors can be a attached to this at a time.

2. Flexible data storage : It has Internal memory to store 19, 200 data points i.e. hourly data

for continuous 40 days at a time can be stored.

3. Versatile data transfer : Software package is available for automatic routine collection of data

at pre determined time interval which can be modified as per the need and requirement.

4. Fully protected : It has a weather proof enclosure to protect data logger and peripheral against

dust and moisture. The logger can operate over the range from - 25oC to + 50 oC without any

error.

5. Integral data processing : The processing includes the averages of maximum and minimum

averages of all weather variables, standard deviations, wind vector integration etc.

6. Robust construction : Tripod and mast are build from thick walled, galvanished steel tubing

with nickle-plated fittings. The mast is 3 metre in height with adjustable cross-arm supports for

sensors. The mast can be positoned precisely by independently adjusting tripod legs. Each leg is

provided with a flat foot with 12 mm hole which allows anchorage to the ground by stake or to

concrete. A lightning conductor and earth spike are also included to save the sensors and

datalogger from destructive effects of Thunderstorm and Lightning as and when experienced in the

area. For measurement of weather parameters in and over the Horticutural crops, a mast of 30

metre height (existing in the nearby site in the same field) can be used for sitting the sensors at

desired heights depending upon the height of horticultural crops as per the need and requirement.

7. Minimum maintenance : Once errected, the station requires very little routine attension.

8. Recording device :

It has a 21 X Micrologger as recording device. It is a rugged field-proven datalogger

suitable for any application requiring data acquisition, on line data processing or electronic control.

It is compact and powerfull battery-powered device which effectively combines the functions of

micro-computer, clock, calibrator, scanner, frequency counter and controller with one smaller

enclosure. The 12 volt Nickle-Cadmium battery is chargeable by solar pannel. The micrologger is

programmed to handle almost any task including signal averaging, exite and delay, totaling,

maximum and minimum, standard deviation, scaling, 5th order polynomial processing, low-pass

filtering and wind vector calculation which are fully supported by simple program statements,

together with a histogram command for direct calculation of frequency distributions. Software


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support is available to simplify more complex programming tasks and to avoid inspection and

processing of stored data.

STRUCTURE, FUNCTIONING AND SITTING OF VARIOUS MICRO -METEOROLOGICAL

SENSORS ON AUTOMATIC WEATHER STATION

This Automatic Weather Station (AWS) is composed (Fig.1.) with various

micrometeorological instruments / sensors for monitoring the micrometeorological weather

variables such as Air temperature (oC), Relative humidity (%), Wind speed (m s-1), Wind direction

(degrees from North), Leaf temperature (oC), Leaf wetness ( % of total wet), Solar radiation (W

m-2), Net radiation (W m-2), Rainfall (mm) , Soil temperature (oC) etc. within and above the crop

canopy. A brief description of sensors measuring these weather variables is given under the

following subheads :

1. Air temperature and relative humidity

The air temperature and relative humidity in and above crop canopy are measured by

HMP 35 AC Temperature and Relative Humidity (RH) probes (two sensors). The probe contains a

Vaisala capacitive relative humidity sensor and a precision thermistor. The probe is designed to

be housed in a 41004-5 or URSI radiation shield and is attached with a 3 m long lead wire

and a connector. The length of lead wire can be increased as per the requirement.

2. Wind speed

Wind speed in and above crop canopy is measured by A100R Switching Anemometer

(two sensors) in which a magnet rotates with the rotor spindle. The varying field forces a mercury

wetted reed switch to make contact once per resolution. This instrument is a precision

instrument which is easily interfaced with Datalogger to give accurate measurements of wind run

or mean wind speed in m/s. This instrument is constructed from anodised aluminium alloy,

stainless steels and weather resisting plastics. A stainless steel shaft runs in two precision,

corrosion-resistant ball races. The bearings are protected from the entry of moisture droplets

and dust, resulting the instrument suitable for permanent exposure to the weather. Its sensitivity

is 0.80 revolutions per metre with an overall accuracy of 2 % + 0.1 m s-1.

3. Wind Direction

The wind direction at 3 m height is measured by W200P Potentiometer Wind Vane (one

sensor). This instrument is manufactured by Vector Instruments Ltd. and measures the wind

direction directly in degrees from North. The windvane incorporates a 358 degree micro - torque

potentiomter (wire wound type). The 2 degree gap is filled to ensure operation and a long service

life. The precision ball - bearing races are corrosion - resistant and are protected against the

entry of moisture and dust.

4. Leaf Temperature

The temperature (oC) of leave is measured by K-Type Thermocouples (two sensors).

Copper and constantan thermocouple wires were twisted to form the sensors and are connected

to the leaves of the plants. There is provision of adding two more leaf temperature sensors.


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5. Soil Temperature

The soil temperature (oC) at 10 and 20 cms soil depths are measured by 107 Thermister

Probes (two sensors). These probes incorporate a precision thermistor in a water resistant probe

with a standard 3 m long cable.

6. Leaf Wetness Period

The duration of leaf wetness at crop surface is measured by 237 Wetness Sensing grid.

This grid is suitable for a range of Scientific and Industrial wetness sensing applications. It

provides a simple measure of the degree of wetness of the surface to which they are attached /

exposed and they can also be used to measure the percentage of time for which the surface is

wet or dry. The sensor consists of a rigid epoxy circuit board (75 mm x 60 mm) with interlacing

gold - plated fingers. Condensation or rain on the sensor lowers the resistance between the

fingers which is measured by the datalogger.

7. Solar Radiation

The Solar or Global radiation at 3 m height is being measured by SP1110 Pyranometer

sensor (one sensor). This is a compact high - output thermally stable solar radiation sensor. The

cosine- errected head contains a special high grade Silicon Photocell sensitive to short-wave

radiation with wavelength between 350 and 1100 nm. The head is completely sealed and can be

left indefinitely in exposed conditions. A levelling mount is also available which enables the

pyranometer to be accurately positioned. The output is 10 mv / 1000 W m-2 with excellent

linearity.

8. Net Radiation

The net radiation which is the difference between the incomming solar radiation and the

outgoing radiation received on the crop surface is being measured by Q -7 Net Radiometer (one

sensor). This instrument is high - output thermopile sensor which measures the algebraic sum of

incoming and outgoing all - wave radiation (i.e. short- and long - wave components). Incoming

radiation consists of direct (beam) and diffuse plus long wave irradiance from the sky. Outgoing

radiation consists of reflected solar radiation plus the terrestroal long-wave components. It

consists 60 - junction thermopile with low electrical resistance. The top and bottom surfaces are

painted black and are protected from convective cooling by hemispherial heavy duty

polyethelene windshileds.

9. Rainfall

The rainfall is measured by ARG 100 Aerodynamic Tipping Bucket Raingauge (one

sensor). It is a well designed tipping bucket raingauge which combines durable construction

with very reasonable cost. The gauge offers less resistance to air flow and helps to reduce the

sampling errors that inevitably occur during wind - driven rain. This instrument is constructed from

UV - resistant, vaccum - moulded plastic and consists of a base and an upper collecting funnel.

The base splits into two parts, the inner section supporting the tipping - bucket mechanism and

the outer providing protection and allowing the unit to be bolded firmly to a suitable mounting


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plinth or concrete slab. The gauge resolution is 0.2 mm / tip. the funnel diameter is 25.5 cms.

10. Micrologger enclosure

All the sensors and the logging equipment are supported on a sturly tripod and mast. A

fiberglass housing with lock and key provides as excellent environmental protection for the

datalogger and ancillary equipment. Glass fitted nylon water proof connectors are fitted to the base

of the enclosure and sensors may be removed or replaced with minimum disturbance to the

weather station.

C. Recording & data logger programming in automatic weather station

All these above sensors have been hooked into the 21X Micrologger (Datalogger) which

runs through a chargeable battery charged with Solarex Solar Panels. In order to record the

output of these sensors, a datalogger programme has been prepared in the Computer

depending upon the number of the sensors attached with different channels in the datalogger and

also the frequency and time of observations. This has been done with the help of micro -

programmes developed in the Computer, and the output is converted into the desired units for

each weather variable. Each variable is sensed after each minute and an integrated value

over a period of five minutes is calculated. Twelves such values of each data point is totalled

or averaged over a period of say one hour and is stored in the memory of the datalogger at an

appropriate location at each hour of the day. The data is also averaged or totalled from each

day called Julian day (i.e. the day of a year from Ist January) from the date of planting / sowing

of the crop in the field. In the present study the recording of micrometeorological weather

variables by AWS were started one month before the first sowing of potato crop and continued till

the end of the Potato crop season. The crop var. Kufri Bahar which is sensitive to Late Blight of

Potato was planted in three dates viz. D1 (20 - 10 - 2010, D2 (30 - 10-2010) and D3 (10 -11 –

2010-) under four irrigation treatments viz. one irrigation, two irrigations, three irrigations and four

irrigations. The observations on micro-meteorological variables in crop field since October 01,

2010 and continued till harvesting of crop of all planting dates depending upon the maturity of

crop in March 2011. The incidence of Late Blight of Potato is monitored on day by day basis and

will continue till maturity of crop in all plots. The recording of micro- meteorological data

observations is also continuing till date. The current data of this hour can be noted on the provided

sheet. At a time, the micro-meteorological data of last 40 days can stored in this datalogger and it

can be seen on hourly basis on liquid crystal display (LCD) of the datalogger.

From this data logger each week the micro-meteorological data thus stored in its memory

is transferred into the SM 192 Storage Module by connecting it to the 9 - pin serial I / O port. This

Storage Module is taken to the laboratory and connected to the Computer. From SM -192 using

SC – 532, 9 - pin Peripheral to RS - 232 interface, the data is then transferred into the Computer

in ASCII form using SMCOM programmes developed for this purpose in the form of a Computer

file. From this file the data is then splitted into the hourly as well as into daily values using splitting

programmes like SPLIT 03. PAR and SPLIT 04. PAR, respectively, which have also been


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development on Computer. The data will then be used for identification of micro-meteorological

weather conditions conducive for the occurrence of late blight of potato during the 2009-10

season.

Data sheet for recording of current observations of micro-meteorological variables in the potato field at CRC using automatic weather station The current micro-meteorological weather variables are being recorded by Automatic

Weather Station (AWS) in the field from 01-10-2010 and the date of planting of Potato crop var.

Kufri Bahar in plot is 20-10-2010 during this Rabi season of 2010 - 11 at Crop Research Centre

of the University. The current data can be read on Liquid Crystal Display (LCD) of the Datalogger

of the AWS in the table given below in the specific sequence of attached sensors :

1. Name of the crop : Potato 2. Date of Ist planting of crop : 20-10-2010

3. Stage of the crop : - 4. Julian day : 90

5. Date of observation : 31-03-2011 6. Time of observation : 1600 hrs

-----------------------------------------------------------------------------------------------------------------------------------

S.No. LOCATION NO. WEATHER VARIABLE HEIGHT UNITS

-----------------------------------------------------------------------------------------------------------------------------------

1. 1 Relative Humidity 1 3m %

2. 2 Air Temperature 1 3m oC

3. 3 Relative Humidity 2 crop %

4. 4 Air Temperature 2 crop oC

5. 5 Net Radiation crop W m-2

6. 6 Solar Radiation 3m W m-2

7. 7 Soil Temperature 1 10 cm depth oC

8. 8 Soil Temperature 2 20 cm depth oC

9. 9 Leaf Wetness crop %

10. 10 Wind Direction 3m Degrees

11. 11 Wind Speed 1 3m m s-1

12. 12 Wind Speed 2 crop m s-1

13. 13 Rainfall crop mm

14. 14 Leaf Temperature 1 crop oC

15. 15 Leaf Temperature 2 crop oC


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Toxicological Investigations on the Emerging Pest Problems in the Important Crops

S.N. Tiwari

Department of Entomology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Toxicological investigations have played very important role in increasing food production

in most of the countries. About 10,000 species of insects are known to damage different crops

most of which were unprotected till 1940 when first synthetic organic insecticide DDT belonging to

organochlorine was investigated. This insecticide along with many more active ingredients

protected so many crops for longer duration. However, due to various reasons only a few are

permitted at present in agriculture. In the past so many years many new active ingredients

belonging to organophosphate, carbamate and pyrethroids have also been investigated and used

extensively in different crops. But due to investigation of some new group such as spinosyns,

oxadiazine, pyrezole, nicotinoid, diamide, neristoxine, growth regulator, thiourea and antibiotic

which are highly effective at low dosages and comparatively safe, the plant protection scenario

have changed drastically in many countries including India. At present following active ingredients

are being used in India in different crops for its protection against insect infestation:

Chemical Group / Active Ingredients / Formulations of insecticides

Trade Name of Insecticides

Organochlorine

Endosulfan 35 EC Thiodan (B), Parrysulfan (C), Thiokill (U)

Endosulfan 4 DP Endosulfan (GP)

Lindane 1.3 DP (R) Kanodane (K)

Lindane 6.5 WP (R) Kanodane (K)

Organophosphorus

Acephate 75 SP Twinguard (G), Tamaron Gold (B), Ortain (C), Lancer (U)

Chlorpyrifos 20 EC Chlorguard (G), Trishul(C), Chlorban (U)

Chlorpyrifos 20 TC Navigator (G)

Dichlorvos 76 SC Nuvan (S), Doom (U), MarvexSuper (C)

Dimethoate 30 EC Rogor (B), Nugor (U)

Ethion 50 EC Mitoff (G)

Fenitrothion 40 WDP

Fenitrothion 50 EC Folithion

Fenitrothion 82.5 EC Folithion

Fenthion 82.5 EC

Malathion 50 EC Cythion (C)

Malathion 5 DP Malathion (GP)

Methyl Parathion 50 EC(R) Parahit

Monocrotophos 36 SL Guardian (G), Parryphos(C), Phoskill (U)

Oxydemeton-methyl 25 EC Metasystox (B)

Phenthoate 50 EC Phendal (C)

Phosphamidon 40 SL Sumidon (SC)

Phosphamidon 50 SL Kinadon (U)

Phorate 10 CG Thimet, Umet (U)


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Profenofos 50 EC Curacron (S), Ajanta (C)

Quinalphos 25 EC Quinguard (G), Bayrusil (B), Shakti(C) , Kinalux (U)

Quinalphos 1.5 DP Molquin (GP)

Triazophos 40 EC Trikon (G), Hostathion (B), Kranti (C)

Carbamate

Benfuracarb 40 EC Oncol (C)

Carbaryl 10 DP Sevin Dust (B)

Carbaryl 50 WP Sevin (B)

Carbaryl 85 WP Carbaryl (ACC)

Carbofuran 3 CG Furadan (R), Furan (U), Tatafuran (R)

Carbosulfan 3 CG Carbosulfan(ACC)

Carbosulfan 25 EC Aayudh (C)

Fenobucarb 50 EC (BPMC) Bipvin (B)

Methomyl 40 SP Lannate (DP), Astra (C)

Thiodicarb 75 WP Larvin (B)

Pyrethroid

Alphacypermethrin 10 EC Alphaguard (G)

Alphamethrin 10 EC Sherpa Alpha (B), Alphamar (C)

Bifenthrin 10 EC Canister (C)

Cypermethrin 10 EC Cyperguard 10 (G), Bilcyp (B), Cypermar(C)

Cypermethrin 25 EC Cyperguard 25 (G), Cybil (B), Cyperkill (C)

Deltamethrin 1.8 EC Bitam (B)

Deltamethrin 2.8 EC Decaguard (G), Decis (B)

Deltamethrin 11 EC Decis 100 (B)

Fenpropathrin 30 EC

Fenvalerate 20 EC Fenfen(C)

Fenvalerate 0.4% DP Molfen (GP)

Lambda-cyhalothrin 2.5EC Aakash (C)

Lambda-cyhalothrin 5 EC Karate (S),Pyrister (C)

Lambda-cyhalothrin 5 CS Karate Geon (S)

Permethrin 25 EC Permasect (C)

Etofenprox 10 EC Etofenprox (ACC)

Spinosyn Fermentation metabolite of the actinomycete Saccharopolyspora spinosa, a soil-inhabiting microorganism

Spinosad 45 EC Spintor(B) Tracer (DP)

Oxadiazine

Indoxacarb 14.5 SC Kingdoxa (G), Awant (DP), Daksh (R)

Pyrazole

Ethiprole 10 SC Ethiprole (B)

Fipronil 0.3 GR Regent GR (B), Mahaveer (G)

Fipronil 5 SC Regent SC (B), Mahaveer (G)

Fipronil 5 FS

Nicotinoid

Acetamiprid 20 SP Polar (Gharda), Rekord (DP), Scuba(C)

Clothianidin 50 WDG Dantop (N)

Imidacloprid 17.8 SL Maharaja (G), Confidor 200 (B), Seamer (DP),Parrymida (C)

Imidacloprid 70 WS Gaucho WS (B)

Imidacloprid 70 WG Admire (B)

Imidacloprid 48 FS Gaucho 600 (B)

Thiacloprid 21.7 SC Calypso (B)

Thiamethoxam 25 WSG Actara (S)

Diamides


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Chlorantraniliprole 20SC Coragen (DP), Rynaxypyre (DP)

Flubendiamide 480SC Fame (B)

Nereistoxin Isolated from a marine annelid, Lumbrineris heteropoda

Cartap 4 GR Kraft (G), Parry Ratna (C), Sanvex (N)

Cartap 50 SP Josh(C), Sanvex (N), Cartox (R)

Growth regulators

Buprofezin 25 SC Applaud (R)

Diflubenzuron 25 WP Dimilin

Flufenoxuron 10 DC Cascade

Lufenuron 5 EC Cigna (S)

Novaluron 10 EC Caesar (DP)

Thiourea

Diafenthiuron 50 WP Pegasus (S)

Antibiotic

Emamectin benzoate 5 SG Proclaim (S)

Fumigant

Aluminium Phosphide 56% Tablet (R)

Celphos (E), Quickphos (U)

Aluminium Phosphide 15% Tablet (R)

Quickphos (U)

Aluminium Phosphide 56% Powder (R)

Celphos (E),Fumino (U)

Ready to use mixtures

Chlorpyrifos 50% + Cypermethrin 5% EC

Hamala 550 (G), Catch (C)

Triazophos 35% + Deltamethrin 1% EC

Spark (B)

Deltamethrin 0.72% + Buprofezin 5.65 % EC

Dadeci 5.625 (B)

Profenofos 40% + Cypermethrin 4% EC

Polytrin (S)

Quinalphos 20% + Cypermethrin 3% EC

Prachand (C)

Acaricide

Abamectin 1.9 EC Vertimec (S)

Dicofol 18.5 EC Delcofol , Tiktok (U)

Ethion 50% EC Coromit

Fenazaquin 10% EC Magister (DP)

Rodenticide

Bromadiolone 0.005 % RB Roban (P)

Zinc Phosphide Ratol (U)

Molluscicide

Metaldehyde Snailkill (PIL)

(R)- Restricted – To be used under technical supervision

G- Gharda Chemicals Limited, B- Bayer CropScience Limited, S- Syngenta India Limited,

C- Coromandal Fertilizers Limited, U-United Phosphorus Limited, E-Excel Crop Care Limited, GP-

Gujrat Pesticides, K-Kanoria Chemicals, CA-Cynamid Agro, DP-DuPont, M-Mansanto, SC-

Sudarshan Chemicals, R-Rallis, P-PCI, H-Hindustan Antibiotic Limited, I-Indofil, B-BASF, A-Amvac

Rasayan, SK-Shivalik, N-Nagarjuna ; DK-Dhanuka, PIL-Pesticide India Limited


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HPLC – An Important Tool for assessment of Fungicide residues in Crops

Anjana Srivastava

Department of Chemistry, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

High-performance liquid chromatography (HPLC) is a form of liquid chromatography to

separate compounds that are dissolved in solution.

Compounds are separated by injecting a plug of the sample mixture onto the column. The

different components in the mixture pass through the column at different rates due to differences in

their partitioning behavior between the mobile liquid phase and the stationary phase.

Functional description of the HPLC instrument Mobile phase reservoir, filtering

Pump

Injector

Column

Detector

Data system

The choice of appropriate mobile phase and column play a very important role in optimizing

conditions for HPLC analysis. The mobile phase is less polar than the stationary phase in normal

phase HPLC but in RP-HPLC it is more polar than the stationary phase. Solvents must be

degassed to eliminate formation of bubbles. The pumps provide a steady high pressure with no

pulsating, and can be programmed to vary the composition of the solvent during the course of the

separation.

The heart of the system is the column where separation occurs. Since the stationary phase

is composed of micrometre size porous particles, a high pressure pump is required to move the

mobile phase through the column.

The chromatographic process begins by injecting the solute onto the top of the column.


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Separation of components occur as the analytes and mobile phase are pumped through the

column. Eventually, each component elutes from the column as a narrow band (or peak) which is

detected on the recorder.

Detection of the eluting components is important, and this can be either selective or

universal, depending upon the detector used. The response of the detector to each component is

displayed on a chart recorder or computer screen and is known as a chromatogram. To collect,

store and analyse the chromatographic data, computer, integrator, and other data processing

equipment are frequently used.

Quantitative analysis by HPLC

A calibration curve is created using the standard sample The area of a peak is proportional

to the concentration of the corresponding component. The concentration of the compound of

interest can be determined from the peak area of the detected compound

Attention should be given to the fact that a qualitative analysis includes many uncertainties.

Other components may also elute together with the target component. LC and GC systems are

good at determining the content of a certain component in a sample, rather than the types of the

components of a sample.

Use of HPLC in pesticide / fungicide residue analysis

Due to the indiscriminate use of pesticides for different applications, important

environmental problems are emerging that are a risk to plant, animal, and human health.

Pesticide residue in crops refers to the pesticides insecticides, fungicides, herbicides etc.) that

may remain on or in food after they are applied to food crops. The levels of these residues in foods

is often stipulated by regulatory bodies in many countries.

Pesticide residue analysis is defined as both the qualitative and quantitative analysis of the

representative samples drawn from agricultural field, market and environment for pesticides and

their toxic metabolites.

The European Union issues new and revised Maximum Residue Limits (MRLs) from time

to time for the different pesticides used across the world. The revision is intended to simplify the

previous system, under which certain pesticide residues are regulated by the Commission.

Fungicides are one group of these pesticides that are used primarily to control spoilage of crops as


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a result of fungal attack. Fungicides in general represent approximately 20 to 25 percent of all

pesticides used.

HPLC method development for fungicides

The 3 critical components considered for developing an HPLC method for fungicide

residues are: sample preparation / extraction, HPLC analysis and standardization (calculations).

1. Sample preparation / extraction and cleanup

A comprehensive literature search of the chemical and physical properties of the analytes

(and other structurally related compounds) is essential to ensure the success of the method.

Most sample preparations involve the use of organic-aqueous and acid-base extraction

techniques. Therefore, literature survey is very helpful to understand the solubility and pKa of the

analytes.

Solubility in different organic or aqueous solvents determines the best composition of the

sample solvent. pKa determines the pH in which the analyte will exist as a neutral or ionic species.

This information will facilitate an efficient sample extraction scheme and determine the optimum

pH in mobile phase to achieve good separations.

2. HPLC analysis

The LC analysis of these substances can be challenging. After suitable selection of solvent

for extraction, a proper choice of column and mobile phase is also essential. for example,

Thiabendazole,shows significant tailing on most silica based LC columns, particularly if the

analysis is performed at acid pH, but both thiabendazole and carbendazim show excellent

retention and good peak shape when analyzed at pH 10 on C18 columns.

Fungicide analysis is carried out mostly on C-8 and C-18 columns with UV, Fluorescence

detectors after appropriate extraction and clean up steps. Post column derivatization has also

been reported. A number of multiresidue determination by C-18 HPLC and UV detector have been

reported for ex. Vinclozolin, iprodione, procymidone while some like thiabendazole, biphenyl, o-

phenylphenol and diphenylamine by fluorimetric determination.

The data is obtained in the form of peaks and for recording the data high speed computers

are used. Recorded data can further be manipulated on the basis of comparison for identification

of the compound of interest.

3. Calculations / Data analysis

The data should always be in triplicate so that it can be subjected to stastistical analysis.

The primary data alongwith S.D or C.V are usually reported in tabular form. They show the spread

of the data and are a measure of precision.

The residue data can also be presented in graphical form as a persistence or dissipation

curve and with the help of these curves the half life values of pesticides / fungicides can be

calculated.

Estimation of Carbendazim fungicide in vegetable samples by HPLC

Carbendazim is a broad spectrum benzimidazole group of systemic fungicides, used for


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controlling several plant diseases. It is basic in nature having high solubility in aqueous organic

solvents.It can remain in solution form in acidic aqueous solutions. When this acidic aqueous

solution is partitioned with organic solvents, most of the coextractives are partitioned with the

solvent whereas carbendazim remains in the aqueous phase.

Extraction from vegetables 25gm vegetable sample

׀Extract with CH3OH (2x50ml)

׀Extract with CH3OH (2x50ml)

׀Partition with CH2Cl2

׀Clean up on a column packed with silica gel and NaCl and activated charcoal

׀Elute with CH2Cl2 + C2H5COOCH3

׀

Evaporate the eluate to dryness and dissolve the residue in HPLC grade CH3OH

HPLC conditions:

Stationary phase : C18 column (25cmx4.6mm i.d)

Mobile phase : CH3OH : H2O (80:20)

Detection : UV 280nm

Estimation of Pyroquilon fungicide in soil, paddy and straw

Pyroquilon, an unclassified group of fungicide used for controlling rice blast disease in rice

plants by seed treatment. It is highly soluble in polar organic solvents.

Extraction from soil, paddy and straw

50g soil/ 25g grain/ 25g straw ׀

Extract with CH3COCH3 : 0.1N HCL (80:20) Filter ׀

Neutralize extract with Na2CO3 and evaporate to dryness ׀

Partition with CH2Cl2: H2O ׀

Dry over MgSO4 and filter ׀

Concentrate the eluent to 1ml and pass through SPE cartridge loaded with silica ׀

Elute with 5ml solvent ׀

Evaporate the solvent under a stream of N2

׀Dissolve residue in 1ml mobile phase

HPLC conditions:

Stationary phase : C18 column (25cmx4.6mm i.d)

Mobile phase : CH3CN : H2O (30:70)

Detection : UV 254nm


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Novelties in Mango Malformation Research

D.K. Chakrabarti N. D. University of Agriculture and Technology, Faizabad (UP)

In recent years no other plant disease has drawn so much attention from scientists of

various disciplines and generated such high-pitched animated debate as mango malformation.

The sequence of events that unraveled the confusion in understanding its cause and thereafter

stepwise revelation of different aspects of the disease leading to a common agreement about

nature of its causal organism and developing integrated management practices makes a

fascinating story. Here attempts have been made to trace the course of research of mango

malformation since its first report in 1891 till date. The publications that have mooted new ideas

and directed the course of the investigations have been specially mentioned.

In the initial years i.e. upto the fifties, the research was limited to the visual observations and

reporting the disease symptoms and severity; attempts were also made to speculate the probable

cause and possible remedies. During this period erophyid mites were the prime suspects as

causal organism. Besides the hypothesis of virus origin of the disease was mooted, both

vegetative and floral malformation were envisaged as the manifestations of the same disease and

attempts were made to reduce the disease incidence through eradication of malformed plant parts.

Some of the important findings during this period are:

Initially the malformation was reported as abnormal manifestations on inflorescences. But

during this time manifestation of the disease on branches of grown up trees and top of the

young seedlings were recorded.

The term “Bunchy top” was first time used to denote seedling malformation; thus

distinguishing it from vegetative malformation.

The association of the eriophyid mite Aceria mangifera with malformation was a significant

report.

The idea that the disease is caused by a virus was also mooted which took long years to

clear off.

The research in the sixties are marked by systemic approach to identify the cause of the

disease. Attempts were made to prove Koch’s postulates for the first time both with eriophyid mites

and a fungus Fusarium moniliforme, the two major suspected causal organisms. The important

research findings during this period are:

Disturbed C/N ratio was implicated to contribute in the disease symptoms.

F. moniliforme was found to be associated with the malformed tissues and malformation

symptoms were reproduced by artificial inoculation with the isolated fungus.

On the other hand, a group of scientists reproduced malformed shoots and panicles by

inoculating just sprouting buds with mites taken from malformed twigs.

The role of temperature in the disease manifestation that has become a favourite aspect in


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later years was initiated this time.

A remarkable discovery of this time was control of mango malformation by removing

malformed shoots and panicles.

The research in seventies witnessed an intensive investigation on the biochemical and

physiological alteration in malformed plants. The horticulturists and plant physiologists interpreted

the changes as the cause of the malady while the plant pathologists viewed them as the resultant

of the pathogenic invasion (F. moniliforme) or physiology of pathogenesis. The important

observations are:

A control measure consisting of deblossoming and naphthyl acetic acid (NAA) spray which

is till date the favourite recommendation for horticulturists and plant physiologists was

suggested.

Differences in growth hormone gibberellins, and protein and DNA contents between

healthy and malformed tissues were determined and speculated that these qualitative and

quantitative changes of the biochemical components induced the disease symptoms.

In seventies a substantial changes in perspectives were recorded. To confirm or disprove

the contention of horticulturists and plant physiologists that the aberrant biochemical constituents

of the host cause the malady, plant pathologists first inoculated the healthy plants with the

pathogen and subsequently reproduced the similar biochemical changes. Thus convinced that the

abnormal biochemical constituents were not the cause of the disease; on the contrary, these were

the results of the pathogenic invasion.

Artificially inoculating the healthy host tissues, biochemical changes in protein and nitrogen

content, cell wall components and oxidative enzymes activity similar to that of naturally

malformed plants were reproduced.

F. moniliforme was renamed as F. moniliforme var. subglutinans.

Primary indications towards host-specificity of the pathogen and its dependence on

external wounding agencies, biotic or abiotic, to enter the host came into the fore.

The presence of toxins of F. moniliforme var. subglutinans was detected in malformed

cells; the chemical nature of the toxins and their role in producing the disease symptoms

was established.

First experimental proof of micronutrient deficiency in malformed tissues was produced.

The idea of implementation of quarantine rule to prevent distant spread of the disease was

mooted.

In the eighties, most of the research publications directly or indirectly substantiated the

pathogenic origin of the disease. In addition to the estimation of growth hormones in malformed

tissues, interest in the disease epidemiology was also become apparent.

Elaborate authentic experimentation conclusively disproved the virus origin of the disease.

Further information in support of the involvement of the fusarial toxins in the disease


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manifestation was made available. In thiscontext, a toxic compound Malformin, usually

secreted by Aspergillus niger is to be mentioned especially.

The disease specific GA and cytokinins produced by the pathogen both in vitro and vivo

were identified.

However, in depth study on the physiology of pathogenesis strongly supported the

contention that the disease manifestation is the combined effects of the aberrant host

metabolites (toxic principles, TP) or (mangiferin, zoosterols, abnormal GA or cytokinins)

and the fusarial toxins (malformation inducing principles, MIP) or (trichothecenes, T-2

toxins, zearalenone, abscisic acid).

Despite the strong evidence supporting F. moniliforme var. subglutinans as the causal

organism of the disease, some publications cast doubt on the fact that the fungus is responsible

for mango malformation. Hence, to provide unequivocal evidence, a series of studies using

molecular diagnostic tools were undertaken in nineties. This period also witnessed large number of

publications on the epidemiology that was so far poorly understood. Besides, some disease

forecasting models were proposed.

Improved technologies such as vegetative compatibility (VCG) and use of GUS reporter

gene further confirmed F. moniliforme var. subglutinans as the causal organism of the

disease.

Biochemical evidence were put forward to establish it as a physiological race of F.

moniliforme var. subglutinas and was proposed to name it as F. moniliforme var.

subglutinans f. sp. mangiferae. The mechanism of transformation of the fungus into a

physiologic race was also reported.

Various epidemiological aspects viz. structure of the epidemic, seasonal variation of the

pathogen vis-à-vis the disease incidence in relation to environmental parameters,

mangiferin content and flushing of the host, synergistic role of a new group of

mycophagus mite with the pathogen, disease dissemination and variation in symptom

expression and virulence of the pathogen under adverse agro-climatic conditions were

reported.

Role of ethylene in malformation was intensively investigated.

Mathematical models forecasting the disease outbreak and for assessment in yield loss

were proposed.

A single step control measure was replaced with integrated management strategy. The

IPM strategy was formulated keeping the disease epidemiology in view.

In the past few years, also a plethora of convincing experimental evidence supporting F.

moniliforme var. subglutinanas as the causal organism have been generated. Its taxonomic

position was reviewed and nomenclature of F. moniliforme var. subglutinanas from mango has

been revised. Subsequently many new aspects of epidemiology have been focused.


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Improved inoculation technique has been developed which has made possible to

reproduce both vegetative and floral malformation symptoms consistently and easily.

Chromosomal anomalies during microsporogenesis in malformed flowers resulting into

abortive pollens were reported.

The PR protein that imparts resistance in the host plant against the pathogen was

identified.

Studies using different molecular tools such as nuclear and mitochondrial DNA sequences

and isozymes and tests for mating types and compatibility concluded that Fusarium isolate

from malformed mango tissues represented a new species of G. fujikuroi complex and a

discrete taxon. It was described as F. mangiferae.

The studies on population genetics conducted with the F. mangiferae showed very little

variations among isolates from different region of the world. F. mangifeae in different

geographical areas was most probably introduced from India. It was also assumed that the

pathogen have originated in India.

A computerized expert system has been developed to predict the disease incidence in any

state of India and to suggest appropriate an IPM strategy.

But we have “miles to go” to completely unwind the mystery of malformation and find out an

easy and a single stroke solution. In view of the current enthusiasm among the new generation of

scientists and their improved techniques, it may be hoped that it is not far away when the stride to

tame the devastating malady will trump the success of century old efforts.

However, once India was the epicenter of mango malformation research. But now-a-days

hardly any scientist in India venture to work on this problem. On the contrary, a number of

scientists in USA, Israel, South Africa, Australia are vigorously and constantly pursuing the

research on malformation. Perhaps we are looking towards these countries to come with

technologies that will save our mango orchards from the tentacles of malformation!


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Precision Agriculture for Higher Productivity and Profitability

Rajeew Kumar and Vineeta Department of Agronomy, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Traditional agriculture provides goods required by the farming family usually without any

significant surplus or sale. But burgeoning population compel us to go for more food, which

resulted unstable farming system. The traditional agriculture is an important reserve and source of

biodiversity. Food demand laid the birth of modern agriculture where more crops can be grown on

less land. Modern agriculture is dependent on fossil fuels, mostly for mechanized agriculture. The

goal of modern agriculture practices is to help farmers provide an affordable supply of food to meet

the demands of a growing population. The challenge for the future is how to increase yields in

traditional systems while retaining a certain measure of their integrity. Future agriculture requires

to produce more food per unit land simultaneously consider the threat of deterioration of natural

resources as well as environment. Modern agriculture is based on uniform recommendation

technique. However, this is need of hour to take care of individual site/plant to enhance their

productivity. Under such circumstances precision agriculture is only alternative.

1. Precision agriculture

Precision agriculture (PA) – also known as precision farming, prescription farming, variable

rate technology (VRT) and site specific agriculture – is a current buzz word among the agricultural

circles and considered as the agricultural system of the 21st century, as it symbolizes a better

balance between reliance on traditional knowledge and information – and management – intensive

technologies. It is an integrated agricultural management strategy where farmers can adjust input

use and cultivation methods – including seed, fertilizer, pesticide, and water application, varietal

selection, planting, tillage, harvesting – according to varying soil, crop and other field conditions. In

brief, precision agriculture refers to tailoring crop and soil management practices according to

variation in crop and soil conditions within each field. PF differs from conventional farming that is

based on uniform treatments across a field. A key difference between conventional management

and precision agriculture is the application of modern information technologies can be viewed as

technologies that improves the efficiency of inputs applied but requires higher investment capital

and labor than traditional technology. It involves mapping and analyzing within field variability and

linking spatial relationships to management decisions, thereby helping farmers to look at their

farms, crops and practice from and entirely new perspective. PA thus provides a framework of

information with farmers can make both production and management decisions.

PA promises to revolutionize form management as it offers a variety of potential benefits in

profitability, productivity, sustainability, crop quality, environmental protection, on – farm quality of

life, food safety, and rural economic development. Studies in USA, Canada, Europe and Australia

have shown that PF permits reductions in input application rates without sacrificing crop yields.

Refinement and wider application of PA technologies in India can help in lowering production


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costs, enhancing higher productivity and environmental benefits, and better utilization of natural

resources. For example, site – specific application of irrigation in wheat of Punjab and Haryana,

pesticides in cotton and fertilizers applications in plantations of oil palm in South India and coffee

and tea garden of Eastern India can greatly reduce production costs and decrease environmental

loading of chemicals.

When PA technologies judiciously implemented, farmers could be benefited in many ways.

In the short term, growers can use forecast based on remote sensing and alleviate problems such

as water stress, nutrient deficiency and pests/diseases more effectivity. Database – building

benefits will be in the form of accurate farm document keeping for effective management of inputs,

property, machinery and labor, and efficient monitoring of environmental quality through recording

the amounts and location of input through applying at exact locations that produce maximum profit

margins. PF technologies also increase opportunities for skilled employment in farming, and

provide new tools for evaluating multifunctional character (including non – market functions) or

agriculture and land.

2. Integrated technology components

Precision agriculture technologies provide three basic requirements for precise and

sustainable agricultural management. These are: Ability to identify precise location of field, 2.

Ability to gather and analysis information on spatio – temporal variability of soil and crop conditions

at field level, and 3. Ability to adjust input use and farming practices to maximize benefits from

each field location. Precision farming involves integrated technologies such as (GPS), (GIS),

Remote Sensing, Variable Rate Technology (VRT), Crop models, yield monitors and precision

irrigation. Various configurations of these technologies are suitable for different PF operations.

Information technology such as the Internet is good means for some agri – business companies to

deliver their services and products.

2.1 GPS

More recently farmer in USA have gained access to site – specific technology through use

of GPS. Currently a constellation of 27 satellites developed by the US Department of Defense –

provides geospatial accuracy to farm practices and enables farmers to identify and compare

characteristic of each field site (location of soil sample or pest data are collection and compared to

soil and crop vigor map, respectively). A minimum of four satellites is required to get good position

information. If a GPS receiver is used along with a ground reference station (Differential GPS), any

location on earth can be identified to within one square meter. The value of knowing a precise

location within inches is that 1) locations of soil samples and the laboratory results can be

compared to a soil map, 2) fertilizer and pesticides can be prescribed to fit soil properties (clay and

organic matter content) and soil conditions (relief and drainage), 3) tillage adjustments can be

made as one finds various conditions across the field, and 4) one can monitor and record yield

date as one goes across the field.


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2.2 GIS

Geographic information system is a computerized data base management and retrieval

system, which offers spatial solutions to many problems relating crop productivity and agronomic

management. It can integrate all types of spatial and non spatial information collected form

different sources and interface with other decision support tools such as crop models. GIS can

display analyzed information in maps that allow (a) better understanding of interactions among

crop vigor, yield, nutrients status, pests & disease stress, weeds and other factors, and (b)

decision-making based on such spatial relationships. Recently, many types of commercial and

user specific GIS software with varying functionality are now available. For example, AGROMA

from PCI, AGRIMAPPER, DSSAT v 3.5 with Arc/View interface from IBSNAT A comprehensive

farm GIS contains base maps such as topography, soil type, N, P, K and other nutrient levels, soil

moisture, pH, etc. data on crop rotations, tillage, nutrient and pesticide applications, yields, etc.

can also be stored. GIS is useful to create fertility, weed and pest intensity maps, which can then

be used for making maps that show recommended application rate of nutrients or pesticides.

2.3 Remote Sensing

Satellite has inherent quality of providing information on spatial variability in crops caused

by natural and agronomic practices. Some farmers have already received benefits from satellite

data. Remotely sensed images from LANDSAT, SPOT and IRS LISS III have been used to

distinguish crop species and locate crop stress areas. Commercial satellites to be launched in

future are expected to have ideal sensors specifications for Precision farming such as 3-day

repeat coverage, 1 to 4 meter spatial resolution and image delivery to users within 15 minutes

after acquisition. At present, IKONOS satellite from Imaging has capability to provide multi-spectral

data with 1 to 4 meters spatial resolution for India which make it possible to have information on

actual state of crop in the field. IKONOS is clearly paving the way toward making agricultural

monitoring a reality so that farmers are able to reach their management and planning goals.

Moreover, merged of LISS III + PAN from current IRS series satellites can also shows all crop

fields and thereby helps in field boundary detection and updating of cadastral information along

with cultural and management details. Remotely sensed images can show all fields in a village or

block and spot problems sooner than ground survey, thereby allowing remedial treatments to be

taken up before the stress spreads to other parts of the field. In a field survey, GPS can be used to

pinpoint the stressed area for a detailed examination. Crop vitality indicators can also be

determined using images acquired at different times during a season. Such data when use with

crop, models through calibration of re-initialization of model, can be useful in predicting crop yields.

2.4. Variable rate technology

One method of controlling variability within field is VRT. VRT allows grower to apply the

quantity of crop inputs needed at a precise location in the field based on the individual

characteristics of that location. Typical VRT system includes a computer controller, GPS receiver,

and GIS map databases. Computer controller adjusts the equipment application rate of the crop


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input applied. The computer controller is integrated with the GIS database, which contains the flow

rate instructions for the application equipment. The computer controller uses the location

coordinates from the GPS unit to find the equipment location on the map provided by the GIS unit.

The computer controller reads the instructions from the GIS system and varies the rate of the crop

input being applied as the equipment crosses the field. The computer controller will record the

actual rates applied at each location in the field and store the information in the GIS system, thus

maintaining precise field maps of materials applied.

3. Role of precision agriculture

The real value of precision agriculture for the farmer is that he can adjust seeding rates,

plan more accurate crop protection programs, perform more timely tillage and know the yield

variation within a field. These benefits will enhance the overall cost effectiveness of his crop

production.

3.1. Seeding

Hybrid seeds perform best when placed at spacing that allows the plants to obtain such

benefits as maximum sunlight and moisture. This is best accomplished by varying the seeding rate

according to the soil conditions such as texture, organic matter and available soil moisture. One

would plant fewer seeds in sandy soil as compared to silt loam soils because of less available

moisture. The lower seed population usually has larger heads (ears) of harvested seeds providing

for a maximum yield. Since soils vary even across an individual farm field, the ability to change

seeding rates as one goes across the field allows the farmer to maximize this seeding rate

according to the soil conditions. A computerized soil map of a field on a computer fitted on the

tractor along with a GPS can tell farmers where they are in the field allowing the opportunity to

adjust this seeding rate as they go across their fields.

3.2. Crop Protection

The application of chemicals and fertilizers in proper proportions are of environmental and

economic concern to the farmers. Environmental regulations are calling for the discontinuance of

certain pesticide applications within 100 feet of a stream or water body or well or within 60 feet of

an intermittent stream. Using a GPS along with a digital drainage map, the farmer is able to apply

these pesticides in a safer manner. In fact, the spraying equipment can be preprogrammed to

automatically turn off when it reaches the distance limitation or zone of the drainage feature.

Additionally, farmers can preprogram the rate of pesticide of fertilize to be applied so that only the

amount needed determined by the soil condition is applied varying this rate from one area of the

field to another. This saves money and allows for safer use of these materials.

3.3 Tillage

The ability to vary the depth of tillage along with soil conditions is very important to proper

seedbed preparation, control of weeds and fuel consumption and therefore cost to the farmer.

Most farmers are using conservation tillage which means leaving residues on the soil surface for

erosion control. The use of GPS in making equipment adjustments as one goes across the


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different soil types would mean higher yields and safer production at lower costs. This part of

precision farming is in its infancy. The equipment companies will be announcing tillage equipment

with GPS and selected controls tailored to precision farming in the near future.

3.4 Harvesting

The proof in the use of variable rate technology (adjusting seed, pesticide, fertilizer and

tillage) as one goes across the field is in knowing the precise yields. Combines and other

harvesting equipment can be equipped with weighing devices that are coupled to a GPS. One

literally measures yields on the go. With appropriate software, a yield map is produced showing

the yield variation throughout the field. This allows farmers to inspect the precise location of the

highest and the lowest yielding areas of the field and determine what caused the yield difference. It

allows one to program cost and yield to determine the most profitable practices and rates that

apply to each field location. In my opinion, the use of yield monitors is a good place to start if one

wants to get started in precision farming. Yield data from the same field over 3 + years would

define the weak spots in the field and narrow down the probability of what is causing a log yield.

4. Role of remote sensing in precision agriculture

4.1 Management Zone and Soil Maps

Soil maps are also sometimes used to determine management zones. Soil maps are

becoming part of the GIS database. Except for semi detailed country soil surveys, remote sensing

has not gained wide acceptance as a mapping tool for soil characteristics. This is because “the

reflectance characteristics of the desired soil properties (e.g., organic matter, texture, iron content)

are often confused by variability in soil moisture content, surface roughness, climate factors, solar

zenith angle, and view angle”.

4.2 Monitor Crop Health

Remote sensing data and images provide farmers with the ability to monitor the health and

condition of crops. Stressed plants reflect various wavelengths of light that are different from

healthy plants. Healthy plants reflect more infrared energy from the spongy mesophyll plant leaf

tissue than stressed plants. By being able to detect areas of plant stress before its becomes

visible, farmers will have additional time to analyze the problem area and apply a treatment.

4.3 Water Stress

The use of remote sensors to directly measure soil moisture has had very limited success.

Synthetic Aperture Radar (“SAR”) sensors are sensitive to soil moisture and they have been used

to directly measure soil moisture. SAR data requires extensive use of processing to remove

surface induced noise such as soil surface roughness, revelation, and topography. A crop evapo-

transpiration rate decrease is an indicator of crop water stress or other crop problems such as

plant infestation. Remote sensing images have been combined with a crop water stress index

(“CWSI”) model to measure field variations.

4.4 Weed Management

Aerial remote sensing has not yet proved to be very useful in monitoring and locating


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dispersed weed populations. Some difficulties encountered are that weeds often will be dispersed

throughout a crop that is spectrally similar, and very large-scale high resolution images will be

needed for detection and identification.

4.5 Insect Detection

Aerial or satellite remote sensing has not been successfully used to identify and locate

insects directly. Indirect detection of insects though the detection of plant stress has generally not

been used in annual crops. The economic injury level for treatment is usually exceeded by the

time plant stress is detected by remote sending.

4.6 Nutrient Stress

Plant nitrogen stress areas can be located in the field using high-resolution color infrared

aerial images. The reflectance of near infrared, visible red and visible green wavelengths have a

high correlation to the amount of applied nitrogen in the field. Canopy reflectance of red provides a

good estimate of actual crop yields.

4.7 Yield Forecasting

For crops such as wheat, grain sorghum, production yields, leaf area index (“LAI”), crop

height and biomass have been correlated with NDVI data obtained from multispectral images. In

order to get reasonably accurate yield predictions this data must be combined with input from crop

growth and weather models during the growing season.

5. Scope of precision agriculture in India

Precision farming technologies is a suite of many high-tech tools but there is no need to

adopt all PF technologies at once to start benefiting from them. Many farmers can begin by using

only a part of the technology, as even partial use can bring many benefits. In fact, applying the

entire range of technologies is not profitable in several cases, particularly for technologies that are

not scale-neutral. For example, small farmers in India cannot afford on their own, but some private

sector support is needed for the advancement of data acquisition and analysis methods, including

sensing technologies, sampling methods, data base systems, and geospatial methods. Some of

the agribusiness companies like Nagarjun Fertilizers Company Limited, BAYER India Ltd. and

Mahyco Seeds Pvt. Limited should come forward and get actively involved in extending the

services on precision farming technologies to the farmers someway. There are many companies

have involved in these extension activities and helping to the farmers.

Precision farming technologies is likely to provide a greater profitability advantage for (a)

high-value crops, (b) areas where input costs are high, and (c) areas where production conditions

are very heterogeneous. The implementation of precision agriculture technologies in India should

have two different strategies – one for the low input subsistence agriculture and the other for input-

intensive profit-making agriculture. In case of former, the increase in productivity is the prime

concern. Here, the system has to be converted to information-based agriculture, where farmer has

spatial information about the soil and crop. This information can be used for efficient input

application. Since the field size are small in this situation individually bunded field or a group of


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field can be considered as a unit for variable rate application. However, for the latter case, such as

rice and wheat of Indo-Gangetic belt and the horticultural crops like grape (Maharashtra), potato

(Punjab), tea (Assam) where the field size arer large and farmers are rich, input use efficiency is

prime concern. Here, remote sensing data can be used to identify the spatial and temporal

variability and necessary actions can be adopted using sophisticated equipments like variable rate

technology. Adoption of PF techniques aimed at irrigation management, nutrient management and

integrated pest management will obviously be a priority for such crops.

6. Limitations for adoption of precision agriculture in India

There are many limitations in adopting this high-tech precision farming technology in India.

Some of them include:

High cost of obtaining site-specific satellite data

Lack of willingness to share spatial data among various organizations

Complexity of tools and techniques requiring new skills

Culture, attitude and perceptions of farmers including resistance to adoption of new

techniques and lack of awareness of agro-environmental problems

Farmers inability to afford High-tech farm equipments

Small farms, heterogeneity of cropping systems, and land tenure/ownership restrictions

Infrastructure and institutional constraints including market imperfections

Lack of success stories of PE adoption and lack of demonstrated impacts on yields

Lack of local technical expertise

Uncertainty on returns from investments to be made on new equipment and information

management system

Lack of transformation of technical know –how to farmers in local language, and

Knowledge and technological gaps including

Inadequate understanding of agronomic factors and their interaction.

Lack of understanding of the geostatistics necessary for displaying spatial variability

of crops and soils using current mapping software, and

Limited ability to integrate information from diverse sources with varying resolutions

and intensities.


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Overcoming Nutritional Deficiencies and Toxicities in Crop Plants

P.C. Srivastava Department of Soil Science, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

The growth of crop plants depends upon a number of soil, climatic and management

factors. Nutrient supply to plants play very important role in plant growth and ultimate crop yield

and quality of produce. When crops fail to absorb any nutrient in sufficient quantities, the metabo-

lism disturbances occur and crops exhibit specific hunger signs. These hunger signs are called

deficiency symptoms, which appear depending upon the mobility of nutrient in plants. Deficiency

symptoms of nitrogen, phosphorus, potassium, magnesium, molybdenum and zinc appear first on

older leaves. The deficiency symptoms of calcium, boron, manganese iron and sulphur appear first

on new leaves and buds. On the other hand, if some of these nutrients are present in excess they

produce toxicity symptoms and require immediate adoption of corrective measures.

Management of nutrient deficiencies in the field requires a thorough knowledge of the

symptoms produced as a result of deficiency or toxicity of the specific nutrient. For the

amelioration of deficiency, corrective measures need to be adopted based on the principles of

integrated nutrient supply system.

Nutrient toxicities especially, in respect of micronutrients are important in certain

geographical regions and can be best managed by using tolerant varieties and chemical

amendments.

Components of nutrient supply system:

In agricultural ecosystem, major sources of plant nutrients are:

Soil

Mineral fertilizers

Organic manures/matter

Amendments

Biofertilizers.

The main aim is to tap all possible sources in a judicious way and ensure their efficient use.

A. Soil source:

In order to enhance the supply of nutrients from soil, the following measures need to be

adopted.

Adoption of appropriate soil management and conservation practices to reduce nutrient

loss.

Amelioration of problem soils to mobilize unavailable nutrients

Maximum utilization of available soil nutrients using appropriate crop variety, cultural

practices and cropping system

Microbiological methods to mobilize unavailable soil nutrients using vesicular-

arbuscular mycorrhizae and Psuedomonas spp.

B. Chemical fertilizers:

More efficient use of chemical fertilizers in the production system is intended. In a country


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like India where the problems of low and unbalanced fertilizer use and food requirement of an ever

increasing population coexist, any approach to further reduce the fertilizer application and

supplementation through alternative sources should be advocated with great caution depending

upon the current level of fertilizer use in the system. The direction should be to maximize

production/unit area/unit time by optimizing fertilizer use efficiency through complementary use of

organics and other alternative sources of plant nutrients. Any additional nutrient applied through

other sources must be taken into account for making up the gap between the recommended and

actual level of fertilizer application.

Higher fertilizer use efficiency can be achieved through:

Use of appropriate fertilizer product

Minimization of nutrient loss by using correct method and time of application

Elimination of all nutritional limiting factors such as primary a- and secondary-nutrients

and improvement in other production factors

Scheduling of fertilizer recommendations

C. Organic manures:

Organic manure/matter is valuable bye-product of farming and allied industries. The

nutrient recycling is possible either by their composting or direct application or mulching. Some of

such sources are-

Farmyard manure, poultry litter, sheep and goat droppings.

Crop residues.

Municipal wastes (Night soil, urine, sewage, sludge)

Slaughter house (blood, bones) and fishery wastes

Bye-products of agro-industries (oil cakes, fruit and vegetable processing wastes,

press-mud rice-husk, bran)

Forest litter, marine algae, sea weeds, water hyacinth, tank silt etc.

D. Biofertilizers:

Suitable microbial culture should be used to tap unavailable soil nutrients. Besides

improving the availability of N to plants, green manuring/leguminous tree leaf manuring and use of

symbiotic and asymbiotic microorganisms also alter the supply of micronutrients. This involves use

of vesicular-arbuscular mycorrhizae and suitable strains of Psuedomonas spp. Microbes capable

of producing growth promoting, antifungal and antibacterial substances can also be used. A

combined inoculation strategy can be adopted to partly reduce the dependence on chemical

fertilizers. This involves an integration of a combination of inoculants with reduced doses of

mineral fertilizers to meet the complete requirement of the crop under a given agro-climatic

condition. The strategy has important relevance in organic farming.

REFERENCES

1. Tisdale, S.L.; Nelson, W.L.; Beaton, J.D. and Havlin, J.L. 1997. Soil Fertility and Fertilizer. 5th ed.

Prentice hall of India.

2. Srivastava, P.C. and Gupta, U.C. 1996. Trace elements in crop production. Oxford. IBH publishing.


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Precision in Soil and Nutrient Management with Special Reference to Subsoil Health

T.C. Thakur

Department of Farm Machinery and Power Engg., GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

India witnessed a remarkable growth on agricultural front particularly during 1970s and 80s

which enabled the country to become self-sufficient in food grain production. The growth in food

grain production started declining during 1990s and presently, it is almost stagnant, forcing the

country to import food grains once again. As the increase in production will come from shrinking

land and water resources, the country is left with no other option but only through improvement in

crop productivity. Soil health degradation has emerged as a major issue responsible for stagnation

in agricultural productivity. In near future, high capacity machines would be required for tillage and

sowing operations, often in a single pass to make the best use of available soil moisture. Subsoiling

and deep tillage after harvest in dry soil conditions will be needed to prevent run-off after the rain

and for enhancing the ‘green water’ storage. Seeding and fertilizer placement in deep furrows

would be required, if the soil moisture recedes beyond the normal seeding depth.

The soil cultivation in India changed over the years as per availability of farm power

sources. During 1960s, the soil cultivation was limited to around 10-12 cm depth with dominant

animate power sources. Although tractors upto 80 h.p. are now available in the country, the soil

management practices have not changed appreciably and confined to shallow depths of 10-15 cm

with rigid tine cultivators and harrows which manage soil almost similar to a country plough.

However, some of the farmers also opt for deep tillage upto 20 cm depth occasionally with mould

board/disc ploughs. It can, therefore, be postulated that the Indian subsoil (>25 cm depth) have

not been cultivated due to lack of tractor power in the past. The current decade, however, has

witnessed a definite shift to high h.p. (>50h.p.) tractors with a share of 8-10% out of over 0.42

million tractors produced annually in the country.

Subsoil compaction and hard pan formation is caused either by natural soil forming

processes or by man made activities such as use of heavy weight machinery, repeated cultivation,

indiscriminate movement of machineries, soil cultivation under wet land condition (paddy field),

slipping wheels in furrows during operation of heavy equipment and so on. The heavy equipment

such as combine harvesters, sugarcane harvesters and other specialized machineries have been /

are being introduced on Indian farms. The weight of self-propelled combines in India ranges from

about 6 t (KS-513 TD) to 7.5 t (Standard self-propelled C-514) while the sugarcane harvesters

with weight of 9 to 12 t may compact soil upto 30-40 cm depths, particularly when working under

moist soil condition. This calls for introduction of matching subsoil cultivation equipment with high

h.p. tractors on Indian farms.

For food security in India, the fertilizer security is of paramount importance. But at

present a huge amount of fertilizers is imported every year to meet the domestic demand which

(c)


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puts heavy pressure on Indian economy and drain of foreign exchange. Here again, the

fertilizer application technology has not changed resulting in poor nutrient utilization efficiency

and consequent low productivity. The application of fertilizers is generally accomplished either

through broadcasting and mixing in upper soil layers or furrow/band placement or drilling along

the seeds during sowing. Broadcasting of fertilizers, especially P and K, results in fixation

problems due to more soil contact while applied N is lost due to volatilization. It has been

reported that only 40-50% of N and 20-30% of P and K fertilizers are used effectively by crops

and the remaining get lost through numerous ways. Even in case of existing seed-cum-fertilizer

drills, the seeds and fertilizers are placed side-by-side in the top 4-6 cm depth, thus resulting in

very poor nutrient utilization efficiency. This is because of the fact that fertilizer remains in the

upper dry zone of soil profile for most part of the cropping period.

Yet another dimension of the present problem is that the soil management and fertilizer

application practices do not match with the crop roots requirement which has been very poorly

investigated in our country. The root length and density of different crops vary dramatically with

variety, soil type and condition, moisture and nutrient status as well as biotic and abiotic stress

conditions. The maximum root length of different crops, viz. wheat (1.6 m), rice (0.7 m), maize

(1.83 m), sugarbeet (0.9 m), soybean (1.8 m), cotton (1.83 m), barely (1.4 m), potato (1.0 m) carrot

(3.0 m) and so on has been reported by Van-Noordwijk and Brouwer (1991). In case of rice

(Var.: Saket 4) about 92% and in case of wheat (Var.: UP 2338) about 60.4% roots have been

found in upper 20 cm depth (Pandey and Singh, 2003). In case of sugarcane more than 50%

roots up to 20 cm depth and 85% roots upto 60 cm are generally noticed but could go deeper

even upto 6 m (Lee, 1926). For soybean about 47% roots upto 18 cm depth have been found

(Sanders and Brown, 1978). These facts call for developing tillage equipment for deep

placement of fertilizers directly into the root zone of crops as per their root density for enhanced

nutrients utilization efficiency. By increasing the uptake efficiency, the same amount of yield can

be obtained with less amount of fertilizer. At Pantnagar, over 20% saving of fertilizers has been

found incase of potato and sugarcane for the same yield as that of conventional practices in the

field experiments conducted on deep and differential placement of fertilizers under the ICAR

National Professor Scheme.

Further, a precisely levelled field is pre-requisite for an efficient surface irrigation system,

in-situ conservation of rain water and introduction of Resource Conservation Technologies (RCTs)

such as zero tillage, raised bed planting etc. The laser aided precision land smoothening

equipment have been in use for decades in many developed countries but were imported in India

in the year 2002, the first one by the Pantnagar University from Pakistan through Rice-Wheat

Consortium. Since then, their number has increased year after year. According to an estimate,

over 3000 units of laser land levellers are available in India which have levelled over 1 Mha of land

mainly in the States of Punjab, Haryana, U.P. and Uttarakhand (RWC, 2009). Results of several

hundreds participatory field trials in these States have brought out several benefits of this


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technology which include water saving of 15-30%, increased nutrient utilization efficiency by 10-

15%, enhanced field efficiency of farm equipment by over 10%, increased net cultivable area by

reduction of bunds/ridges and irrigation channels by 2-5%, and yield advantage of 15 to 30% in

different crops (Jat et al., 2006). The area under laser levelling is increasing at an exponential rate

but for tillage operations in these fields, the same old equipment i.e. mould board/disc ploughs,

harrow, cultivator etc. are being used which cause frequent changes in the level of fields.

Therefore, there is an urgent need to develop and introduce such tillage equipment which could

cultivate not only the top soil but also the subsoil without soil inversion so that the biomass in

different soil layers are maintained in the same zone and at the same time, level of the field is

disturbed to a bare minimum. Some of the subsoil health management technologies / equipment

developed under the ICAR National Professor Scheme are briefly described below :

1. Pant-ICAR Subsoiler-cum-Differential Rate Fertilizer Applicator

This machine has been designed by adopting the soil mechanics principle for maximum

soil disturbance with least resistance. It consisted of a rectangular frame with a pair of adjustable

depth control wheels, main subsoiling winged tine mounted at the centre of rear beam of the frame

for soil disturbance upto 50 cm depth, two shallow leading adjustable winged tines mounted on the

front beam of frame at a spacing of about 2 times the full working depth of main subsoiling tine i.e.

about 1 m and operate at a depth of 20-25 cm, a specially designed fertilizer box with adjustments

for vertical movement for varying application rate, three positive feed metering rollers, a floating

armed ground drive wheel to transmit power to the fertilizer metering shaft and a three point

Category-II hitching system (Fig. 1). It can meter and deliver the recommended doze of fertilizers

either in equal amount through three tines or 75-80% fertilizers by two leading tines and remaining

20-25% fertilizers by the main subsoiling tine at two depths. The metered fertilizer drops onto

inverted-V shape deflector plates mounted underneath the extended wing cover and deposits in

bands of about 22 cm width. The technology has been well adopted by the farming community

and research workers, and has been extended to over 250 ha area. Efforts are being made to get

this machine manufactured and supply to different regions of the country particularly in heavy soils

and rainfed areas for adoption in different cropping systems.

2. Pant-ICAR Deep Soil Volume Loosener-cum-Fertilizer Applicator

It consisted of a rectangular frame, two scientifically designed V-shaped tines, four

inverted-T openers tines, two floating type spiked clod crushers, two fertilizer boxes with metering

system, a floating ground drive wheel for power transmission and other accessories (Fig. 1). This

machine is being extensively used for sugarcane ratoon management as Sugarcane Ratoon

Manager and has covered an area of over 175 ha during 2009-11. It cuts the old roots of plant

sugarcane crop after harvesting by upto 30 cm depth with the help of two V-shaped tines

positioned exactly behind the tractor rear wheels and places fertilizers in bands along both sides of

rows at 20±5 cm depth and at the same time pulverizes the clods and consolidates the loose soil

for moisture conservation. This machine leaves a completely levelled field surface after operation


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and therefore, it is the most suitable machine for soil cultivation in laser levelled fields.

3. Pant-ICAR Subsoiler-cum-Vermicompost and Soil Amendments Applicator

It consisted of a subsoiling unit with wings for soil disturbance upto 40 cm depth and a

fertilizer placement unit driven by the tractor PTO for metering and placement of organic manures

(vermicompost, pressmud, FYM), inorganic fertilizers and soil amendments such as gypsum, lime,

rice husk, cement etc. at different depths. The research trials on application of vermicompost and

NPK at different depths upto 40 cm depth have shown substantial increase in yield of mustard

(Var. Kranti) by over 25% in comparison to conventional method of broadcasting and mixing

fertilizers in top 10 cm soil.

4. Pant-ICAR Conservation Tillage Combine

It consisted of a soil working unit with five winged chisel tines positioned at 450 V- angle on

three frames i.e. one tine at the centre of front beam, two tines at V-angle on middle beam and

another two tines at V-angle on rear beam, fertilizer placement unit and a floating spiked clod

crusher unit (Fig. 1). The initial field trial of Pant-ICAR Conservation Tillage Combine has revealed

that it can till soil to the depth of 20-25 cm without soil inversion and with retention of crop residues

at the surface needed for conversation agriculture, place fertilizers in bands at the tillage depth,

pulverize and consolidate the soil for moisture conservation, all in a single pass. Since all the four

wheels of the tractor move on the levelled field surface (in contrast to one side of tractor wheels

operating in the furrow and compacting / smearing the furrow bottom, thereby farming hard tillage

pan incase of conventional mould board / disc ploughing), formation of hard tillage pan could be all

together retarded. Also, there was no need felt for the levelling of field after operation of the

machine, therefore, it is the best suited for soil cultivation in laser levelled fields. The machine can

be operated with a 50-55 h.p. tractor while tilling a depth of 20 cm and cover a width of 1.6 m as

against a mold board / disc plough which covers a width of about 1.25 m only with 3-bottoms

pulled by the same h.p. range tractor and changes the field surface configuration which requires

additional levelling operation. This machine has, therefore, been developed with an ultimate

objective to replace the M.B. plough / disc plough and to solve the associated problems, as it is

capable of providing complete tillage solution.

5. Pant-ICAR Chiseler-cum-Fertilizer Applicator

This machine was developed for soil cultivation upto 20-25 cm depth and simultaneous

application of fertilizers at tillage depth. It consisted of three winged chisel tines mounted on a

rectangular frame in a V-shape i.e. one winged tine at the centre of front beam and two winged

tines mounted on the rear beam at 450 V-line w.r.t. front tine and a fertilizer box with metering and

ground drive wheel with accessories. The evaluation of the machine on potato for deep and

differential placement of fertilizers i.e. 80% of recommended dose at 15 cm and remaining 20% at

25% depth has resulted in the yield increase of more than 24% over conventional practice. It has

been designed for 35-45 hp tractor range.

The adoption of deep subsoil health management technologies developed in the ICAR


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National Professor Scheme has resulted in reduction of rhizomatous and some other kinds of

weeds, destruction of termite’s colonies and less incidence of stem borer in direct seeded rice

which need to be validated through further research. In the past, one of the reasons for failure of

soybean crop in the Tarai region was due to attack of yellow mosaic grown in comparatively wet

soil conditions. There is a need to carry out research with different tillage options such as raised

bed planter, Pant-ICAR subsoiler-cum-differential rate fertilizer applicator and other deep soil

management equipment to have a cap on high soil moisture regime and related pathological

menace.

Pant-ICAR Subsoiler-cum-Differential Rate

Fertilizer Applicator

b. Pant-ICAR Deep Soil Volume Loosener-

cum-Fertilizer Applicator (Sugarcane Ratoon

Manager)

Pant-ICAR Subsoiler-cum-Vermicompost and Soil Amendments Applicator

Pant-ICAR Conversation Tillage Combine

Fig. 1 Subsoil Health Management Technologies Developed at Pantnagar under ICAR National Professor Scheme


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Bio-control Strategies for the Management of Threatening Diseases by Use of Trichoderma spp

Najam Waris Zaidi

Department of Plant Pathology, GBPUA&T, Pantnagar-263 145 (Uttarakhand)

Trichoderma species are free-living fungi that are common in soil and root ecosystems

throughout the world. They are highly interactive in root, soil and foliar environment. They are

presently in nearly all types of soils and other natural habitats especially those containing high

organic matter. This fungus is a secondary colonizer and is frequently isolated from well

decomposed organic matter. Trichoderma species have also been isolated from root surfaces of

various plants, from decaying barks and from sclerotia and propagules of other fungi. Trichoderma

species have the ability to utilize a wide range of compounds as sole carbon and nitrogen sources

and can utilize monosaccharides, disaccharides, polysaccharides etc. for carbon with ammonia

being the most preferred source of nitrogen. The members of Trichoderma are generally

considered to be aggressive competitors although this trait has also been found to be species

dependent.

Trichoderma species are best friends of higher plants. They not only protect them by killing

or antagonizing their enemies but also improve their overall health including toning up of their

ability to tolerate diseases and pests. They act as symbiont and may colonize epidermal and

cortical cells. This colonization results in improved root growth, which in turn improves overall plant

health. Trichoderma species also make micro- and macro-nutrients available to the plants by

enhancing their availability in soil. They decompose soil organic matter which helps in plant

growth. Trichoderma spp are highly efficient producer of many extra cellular enzymes like

cellulases, chitinases, glucanases, proteases etc. They are being exploited in variety of ways like

source of cellulases (used in foods and textiles and also in poultry feed and chitinases (generating

disease resistant transgenic), in plant disease control (through their anti-fungal and anti-nematode

and plant defense inducing activities), improvement of plant growth and organic matter/compost

decomposition.

General characteristics

More than two hundred years ago, when it was first described by Persoon in 1794,

mycologists mistook Trichoderma Pers.: Fr. for a gasteromycetes. At present Trichoderma is a

readily exploitable source and how this source can be fully utilized for economic gains depends on

a clear understanding of the biology, systematics and biocontrol and other characteristics of this

genus.

Trichoderma: Biology

Most species of Trichoderma are photosensitive, sporulating readily on many natural and

artificial substrates in a concentric pattern in response to diurnal alternation of light and darkness

with conidia being produced during the light period. Trichoderma cultures exhibit “replacement wall


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building type” of conidiogenesis. Another interesting property of Trichoderma spp. is their ability to

produce chlamydospores. These resting structures also have the potential to be exploited for

biological control (Papavizas, 1985).

Most Trichoderma strains are not encountered in nature in association with their perfect

stages and are considered to be strictly mitotic, clonal fungi. This apparent lack of sexuality is also

a barrier to understanding relationships within and among Trichoderma species. Sexual

reproduction is known in Trichoderma in the sense that the only known teleomorphs of

Trichoderma are species of Hypocrea Fr. and closely related genera (Samuels, 1996).

About 35 species of Trichoderma are currently recognized on the basis of morphological

and molecular data. However, T. harzianum, T. virens and T. viride are the three most cited

species of Trichoderma for biological control of plant diseases. A detailed description of these

three species as given by Bisset is as follows:

Trichoderma: as a bio-control agent

Weindling in 1932, for the first time implicated the role of Trichoderma lignorum in the

biological control of citrus seedling disease caused by Rhizoctonia solani. Since this pioneering

work, several reports on successful biocontrol by Trichoderma spp. have accumulated. T.

harzianum, T. viride and T. virens are the most widely used/cited for biological control. They are

reported effective in controlling root rots /wilt complexes and foliar diseases in several crops and

are reported to inhibit a number of soil borne fungi like Rhizoctonia, Pythium, Sclerotinia,

Sclerotium, Fusarium spp., Macrophomina etc. and recently root knot nematode, Meloidogyne

spp.

One of the most interesting aspects of studies on Trichoderma is the varied mechanisms

employed by Trichoderma species to affect disease control. In addition to being parasite of other

fungi recent studies shows that they are opportunistic plant symbionts. They produce or release a

variety of compounds that induce localized or systemic resistance responses. Biocontrol activity of

Trichoderma is due to combination of its ability to serve as antagonist, plant growth promoter, plant

defense inducer, rhizosphere colonizer and neutralizer of pathogen’s activity favouring infection.

I. Trichoderma as a fungal antagonist

As an antagonist, Trichoderma may directly kill the pathogen by mycoparasitism and/or

antibiosis. Also, it may adversely affect the growth and development of the pathogen either by

antibiosis or by competing for the nutrient, oxygen or space. Indirectly, it may contribute by

promoting plant growth which manifests itself as increased root and shoot growth, resistance to

biotic and abiotic stresses and changes in the nutritional status of the plant.

1. Host selectivity

Although Trichoderma spp. has got a very wide host range, there is fairly good degree of

host selectivity at the level of strains/ isolates. Many soil borne fungal pathogens like Rhizoctonia,

Sclerotinia, Sclerotium, Macrophomina etc. form hard resting structure called sclerotia. These

sclerotia play vital role in long term survival of these pathogens in soil. It is difficult to kill these


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sclerotia using fungicides. In general T. virens colonizes and kill these sclerotia, whereas T.

harzianum primarily attack hyphae.

2. Mechanism of antifungal action

Against fungal pathogens, Trichoderma species rely on three major mechanisms viz.

mycoparasitism/ hyperparasitism, antibiosis and competition.

i. Mycoparasitism/ Hyperparasitism

One of the most salient characters of the genus Trichoderma is its ability to parasitize other

fungi. Weindling in 1932 for the first time described the biocontrol of R. solani (causing citrus

seedling disease) by Trichoderma lignorum to mycoparasitism. Mycoparasitism is a complex

process involving tropic growth of the biocontrol agent towards the target organism, coiling and

finally dissolution of the target organism’s cell wall/cell membrane by the activity of enzymes.

(Rather than coiling, hyphae of Trichoderma may grow attached with hyphae of R. solani, form

haustoria, which may penetrate host fungal cell to draw nutrients. Same isolate of Trichoderma

harzianum, against R. solani, may show both coiling and haustoria formation, however, one or

other mechanism may dominate depending upon isolate of the antagonist. Is there any effect of

host fungus on type of structure formed by antagonist is yet to be explored?

Studies on the molecular and cellular aspects of the process of mycoparasitism indicate

that it is an extremely complex process involving several steps and numerous separate genes and

gene products. Trichoderma can detect its host from a distance and on detection it starts

branching in an atypical way towards the fungus. This process is probably induced by nutrient

gradients arising from the host

ii). Enzymes

Most of the pathogenic fungi contain chitin and -glucans in their cell walls. Dissolution or

damage of these structural polymers has adverse effects on the growth of these fungi. Recent

research work has implicated a major role of enzymes in biological control by Trichoderma species

and the secretion of enzymes is reported to be an integral step of the mycoparasitic process of

Trichoderma. Trichoderma species secrete a number of hydrolytic enzymes, which includes

chitinases, proteases, cellulases, glucanases and xylanases. Lorito (1998) listed 10 separate

chitinolytic enzymes alone. Similar levels of diversity are reported to exist for -1,3 glucanases.

Elad et al. (1982) tested the secretion of chitinases and -1,3 glucanases by T. harzianum and

observed that the enzymes degraded hyphae of S. rolfsii. Harman et al. (1989) studied the

involvement of “chitinase and -1,3-glucanase” in Trichoderma mediated biological control.

Geremia et al. (1993) purified and biochemically characterized a serine protease enzyme. Elad

and Kapat (1999) suggested the role of proteases in biocontrol of B. cineria by T. harzianum. For

mycoparasitism of Pythiaceous fungi, -1,4-glucanases may play an important role (Thrane et

al.,1997). Ait-Lahsen (2001) isolated and characterized an exo--1,3- glucanase (AGN 13.1)

enzyme from T. harzianum that degrade - glycosidic linkages of polysaccharides of cell wall of


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fungi. The reactions between T. harzianum strains and various fungal hosts were based on

different mechanisms. This, again, indicates that factors other than chitinase activity are important

to the biocontrol process.

iii) Antibiosis

This is the second major mechanism implicated in the biocontrol of pathogens by

Trichoderma. Two years after reporting the involvement of mycoparasitism in Trichoderma- host

fungus interactions, Weindling in 1934 reported that a strain of T. lignorum produced a “lethal

principle” that was excreted into the surrounding medium. He characterized it and demonstrated

that it was toxic to both R. solani and Sclerotinia americana and named it “gliotoxin”. Later in 1983,

Howell and Stipanovic isolated and described a new antibiotic “gliovirin”, from Gliocladium virens

that was strongly inhibitory to Pythium ultimum and Phytophthora but was ineffective against R.

solani, Theilaviopsis basicola, Rhizopus arrhizus, Bacillus thuringensis and Pseudomonas

fluorescens (Howell et al.,1993). Lifshitz et al. (1986) attributed the control of Pythium species on

peas by T. harzianum to the production of an antibiotic. Similarly, suppressive activity of T. virens

to damping off of Zinnias was correlated to production of antibiotic gliotoxin by the bioagent

(Lumsden et al., 1992). Mutation studies with Trichoderma strains have revealed that mutants

deficient for antibiotic production often lack the ability to control Pythium damping off disease

(Wilhite et al., 1994). At present Trichoderma species are reported to produce a number of

antibiotics. These include gliotoxin and glioviridin from T. virens, viridin, alkyl pyrones, isonitriles,

polyketides, peptaibols, diketopiperazines, sesquiterpenes and some steroids from other

Trichoderma species (Howell, 1998).

iv). Competition and rhizosphere competence

Competition is considered as a ‘classical’ mechanism of biological control. It involves

competition between antagonist and plant pathogen for space and nutrients (Chet, 1987). The idea

of the involvement of this mechanism in biocontrol by Trichoderma has gained popularity in recent

years. It is assumed that the mechanism of competition is involved in biocontrol, if no evidence for

mycoparasitism or antibiosis is found in a particular Trichoderma-host fungus interaction. Howell

(2003) used ultraviolet light irradiation to produce mutants of T. virens, deficient for both

mycoparasitism and antibiotic production. However, the mutants still retained biocontrol efficacy

equal to that of the parent strain against both P. ultimum and R. solani causing cotton seedling

disease. This indicated that neither mycoparsitism nor antibiosis is the principal mechanisms

involved in the biocontrol of seedling disease in cotton.

The omnipresence of Trichoderma in agricultural and natural soils throughout the world

proves that it must be an excellent competitor. In studies conducted by Elad and Kapat (1999)

presented information regarding biocontrol of B. cineria by T. harzianum strain T-39. B. cineria

conidia require external nutrients for germination and infection. When conidia of T-39 were applied

to leaves, germination of conidia of the pathogen was slowed, an effect attributed in part to

competition (Elad, 2000). The competitive ability of Trichoderma and therefore its biocontrol


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potential is affected by soil properties.

v). Signal transduction

The ability of Trichoderma to sense and respond to different environmental conditions,

including the presence of a potential host, is essential for successful colonization of soil, organic

material, and developing plant roots. Sensing of such environmental conditions may occur through

a variety of transduction pathways, which determine the adequate cellular response. Mitogen-

activated protein kinase (MAPK) cascades and G-protein subunits transduce a large variety of

signals, including those associated with pathogenesis.

Mukherjee et al. (2003) investigated role of signaling pathway, mitogen-activated protein

kinase (MAPK) cascades, in parasitism of T. virens. Through single- and double-crossover

recombination, they obtained tmkA loss-of-function mutants. The TmkA transcript was not

detectable in these mutants. Against Rhizoctonia solani hyphae, the knockout mutants exhibited

mycoparasitic coiling and lyses of host hyphae similar to that of the wild type. The mutants,

however, were less effective in colonizing the sclerotia of R. solani. On Sclerotium rolfsii, the

MAPK loss-of-function mutants had reduced antagonistic properties and failed to parasitize the

sclerotia. TmkA-dependent and -independent pathways are thus involved in antagonism against

different hosts. Contrary to this Mendoza-Mendoza et al. (2003) observed that MAPK mutant (tvk1

null mutant) was more virulent against R. solani. These mutants showed a clear increase in the

level of the expression of mycoparasitism-related genes under simulated mycoparasitism and

during direct confrontation with the plant pathogen R. solani. The null mutants displayed an

increased protein secretion phenotype as measured by the production of lytic enzymes in culture

supernatant compared to the wild type. Consistently, biocontrol assays demonstrated that the null

mutants were considerably more effective in disease control than the wild-type strain or a chemical

fungicide. In addition, tvk1 gene disruptant strains sporulated abundantly in submerged cultures, a

condition that is not conducive to sporulation in the wild type. These data suggest that Tvk1 acts as

a negative modulator during host sensing and sporulation in T. virens. They concluded that that the

deletion of a MAPK gene generates a more aggressive parasite and, consequently, a better

biocontrol agent. They further suggested that Trichoderma uses different mechanisms to control

different hosts.

G-protein subunits are involved in transmission of signals for development, pathogenicity,

and secondary metabolism in plant pathogenic and saprophytic fungi. Mukherjee et al. (2004)

cloned two G-protein subunit genes, tgaA and tgaB, from the biocontrol fungus Trichoderma

virens. They compared loss-of-function mutants of tgaA and tgaB with the wild type for their ability

to overgrow colonies of Rhizoctonia solani and Sclerotium rolfsii, and the ability to colonize the

sclerotia of these pathogens in soil. Both mutants grew as well as the wild type and sporulated

normally. Both tgaA and tgaB mutants and the wild type overgrew, coiled, and lysed the mycelia of

R. solani, but tgaA mutants had reduced ability to colonize S. rolfsii colonies. Both mutants


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parasitized the sclerotia of R. solani, but tgaA mutants were unable to parasitize the sclerotia of S.

rolfsii. Thus, tgaA is involved in antagonism against S. rolfsii, but neither G protein subunit is

involved in antagonism against R. solani. T. virens, which has a wide host range, thus employs a

G-protein pathway in a host-specific manner.

II. Trichoderma as an antagonist of nematodes

In recent years Trichoderma spp., have been attributed with the ability to control diseases

caused by nematodes. Root dipping in antagonists suspension not only reduced root knot severity

caused by Meloidogyne but also enhances seedling growth in tomato, brinjal, chili and capsicum

Root dipping of rice seedlings in suspension of T. harzianum reduced severity of root lesion

nematode and improved seedling growth (U.S. Singh, unpublished information). Culture filtrate of

T. harzianum and T. virens suppressed hatching and release of second stage juveniles of

Meloidogyne. Trichoderma harzianum formed loops and trapped second stage juveniles of M.

incognita. Trichoderma penetrated nematode body by forming haustoria like structures and

colonized internally replacing all internal organs with fungal mycelia resulting in death of the

nematode. Egg masses are also penetrated and colonized by T. harzianum. Hyphae of T.

harzianum were attracted towards nematode body in Anguina tritici. This chemotactic response

was not recorded against second stage juveniles of Meloidogyne. This may be because of rapid

motility of juveniles in suspension or on agar medium. Protease production by T. harzianum has

been associated with the reduction in root galling. However, field experiments are still required to

prove the potential of Trichoderma as an effective antagonist against nematodes.

III. Trichoderma as a biofertilizers & plant growth promoter

Apart from the direct inhibition of plant pathogens, Trichoderma spp. are reported to

improve crop health by promotion of plant growth (both root and shoot). It is reported to enhance

growth in a number of plant species like rice, wheat, sorghum, tomato, brinjal, soybean, chickpea,

pea, rajma, chilli, capsicum etc. However, this growth promotary effect was not only dependent on

isolate of Trichoderma but also on plant species cultivar involved. When applied as seed treatment

maximum shoot growth promotion in tomato, brinjal, chilli and pea was caused by T. harzianum

isolates PBAT-13, PBAT-41, PBAT-14 and PBAT-33, respectively. Similarly when T. harzianum

isolate PBAT-43 was applied as seed treatment it resulted in different degree of growth promotion

in different cultivars of rice.

Plant growth promotion is one of the indirect mechanisms employed by Trichoderma spp.

which plays a role in the biocontrol of various plant pathogens and in improvement of plant health.

Treatment with Trichoderma generally increases root and shoot growth, reduces the activity of

deleterious microorganisms in the rhizosphere of plants and improves the nutrient status of the

plant. Growth enhancement by Trichoderma spp. has been observed even in the absence of any

detectable disease and in sterile soil and is not considered to be a side effect of suppression of

disease or minor plant pathogens. Secretion of hormone-like metabolites and release of nutrients

from soil or organic matter, have been proposed as the mechanisms involved in plant growth


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IV. Trichoderma as a symbiont and defense inducer

Till recently the interaction between the bioagent and the host plant was given little

attention. Recent discoveries have shown that in addition to being parasites of other fungi,

Trichoderma act as opportunistic, avirulent plant symbionts. At least some strains establish robust

and long-lasting colonization of root surfaces and penetrate into the epidermis and a few cortical

cells below. They produce or release a variety of compounds that induce localized or systemic

resistance responses. This restricts further advance of the Trichoderma and make the plants

resistant to other diseases. These root–microorganism associations cause substantial changes to

the plant proteome and metabolism. Plants are protected from numerous classes of plant

pathogen by responses that are similar to systemic acquired resistance and rhizobacteria-induced

systemic resistance. Root colonization by Trichoderma spp. also frequently enhances root growth

and development, crop productivity, resistance to abiotic stresses and the uptake and use of

nutrients.

Symbiotic colonization of roots by Trichoderma enhanced root growth, which may be

responsible for increased tolerance of plans to biotic and abiotic stresses. Wheat plants raised

from Trichoderma treated seeds tolerate drought (water stress) better under field condition.

Similarly applications of T. harzianum to roots through colonized compost or by root dip helped in

better establishment and growth of plants in Usar soil

Several studies revealed that some biocontrol agents including Trichoderma spp. are also

able to reduce disease through a plant-mediated mechanism that is phenotypically similar to SAR,

since the resistance is systemically activated and extends to above-ground plant parts. This type

of induced resistance, which is activated by biocontrol agents, is often referred to as induced

systemic resistance (ISR). In one of the first comprehensive studies on induction of resistance by

Trichoderma spp. and the accompanying changes in the host plant, Yedidia et al. (2003)

demonstrated that inoculating roots of 7 day old cucumber seedlings in an aseptic hydroponic

system with T. harzianum T-203 spores initiated plant defense responses in both the roots and

leaves of treated plants. They observed that T. harzianum penetrated the epidermis and outer

cortex of the cucumber roots and the treated plants were more developed compared to the

untreated plants throughout the experiment. The plant response was marked by an increase in the

peroxidase and chitinase activity and by the deposition of callose and cellulose enriched wall

appositions on the inner surface of cell walls even in areas beyond the site of fungal penetration.

The induction of defense response in plants by Trichoderma spp is often associated with

accumulation of various antimicrobial compounds like phytoalexins, PR proteins along with the

strengthening of cell walls and other barriers in the plant cells. Howell et. al. (2000) demonstrated

that seed treatment of cotton with biocontrol preparations of T. virens or application of T. virens

culture filtrate to cotton seedling radicles induced synthesis of terpenoids desoxyhemigossypol,

hemigossypol and gossypol in developing roots in very high concentration and also led to

increased peroxidase activity as compared to that of control. These compounds were inhibitory to


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the cotton seedling pathogen R. solani at quite low concentrations.

Induced-resistance systems in plants are complex. There are three generally recognized

pathways of induced resistance in plants. Two of these pathways involve the direct production of

pathogenesis-related (PR) proteins; in one pathway, the production of PR proteins is generally the

result of attack by pathogenic microorganisms, and in the other pathway, PR proteins are

generally produced as a result of wounding, or necrosis-inducing plant pathogens —for example,

herbivory by insects — although both pathways can be induced by other mechanisms. Typically,

the pathogen-induced pathway relies on salicylic acid produced by the plant as a signaling

molecule, whereas the herbivory-induced pathway relies on jasmonic acid as the signaling

molecule. These compounds, and their analogues, induce similar responses when they are

applied exogenously, and there is considerable crosstalk between the pathways. The jasmonate-

induced pathway is designated as induced systemic resistance. The jasmonate- and salicylate-

induced pathways are characterized by the production of a cascade of PR proteins. These include

antifungal chitinases, glucanases and thaumatins, and oxidative enzymes, such as peroxidases,

polyphenol oxidases and lipoxygenases. Low-molecular-weight compounds with antimicrobial

properties (phytoalexins) can also accumulate. The triggering molecules in the Trichoderma

responses are unknown. The third type of induced resistance has been best-described as being

induced by non-pathogenic, root-associated bacteria, and is termed as rhizobacteria-induced

systemic resistance (RISR). It is phenotypically similar to the jasmonate- and salicylate-induced

systems, as it results in systemic resistance to plant diseases. However, it is functionally very

different, as the PR proteins and phytoalexins are not induced by root colonization by the

rhizobacteria in the absence of attack by plant-pathogenic microorganisms. However, once

pathogen attack occurs, the magnitude of the plant response to attack is increased and disease is

reduced. Thus, RISR results in a potentiation of plant defense responses in the absence of the

cascade of proteins that is typical of the jasmonate- or salicylate-induced systems. Treatment with

an inhibitor of ethylene action strongly inhibited the protective effect of Trichoderma on plants thus

indicating that ethylene signal is required for ISR. Moreover, application of jasmonic acid

production inhibitor completely abolished the protective effect of Trichoderma on plants. These

experiments confirmed that like in case of rhizospheric bacteria, induction of resistance by

Trichoderma also occurs through the jasmonic acid/ ethylene signaling pathway.

The role of a mitogen activated protein kinase TmkA in inducing systemic resistance in

cucumber against a bacterial pathogen Pseudomonas syringae pv. lacrymans was investigated by

Viterbo et. al. (2005) using tmkA loss-of function mutants of Trichoderma virens. They observed

that the mutants were able to colonize the plant roots as effectively as the wild type strain, but

failed to induce a full systemic resistance against the leaf pathogen. Interactions with the plant

roots enhanced the level of tmkA transcript in T. virens and its homologue in T. asperellum. At the

protein level activation of two forms reacting to the phospho-p44/42 MAPK antibody were

detected. They further demonstrated that the tmkA mutants retained their biocontrol potential in


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soil against Rhizoctonia solani, but were not effective in reducing disease incidence against

Sclerotium rolfsii. They concluded that unlike in many plant-pathogen interactions, Trichoderma

TmkA MAPK is not involved in limited root colonization. Trichoderma, however, needs MAPK

signaling in order to induce full systemic resistance in the plant. Regardless of the exact

mechanism responsible, this study demonstrates that a conserved fungal signal transduction

pathway is involved in the three-way interaction between biocontrol fungus, plant pathogen, and

plant and that different signals control mycoparasitic activity and ability to induce plant systemic

resistance.

Therefore it may be concluded that the interactions of Trichoderma with its host fungi are

very complex often influenced by the particular strain of Trichoderma involved, the host fungus in

question and maybe several other ecological factors.

V. Trichoderma as a compost colonizer

Trichoderma can colonize and decompose dead organic matter. Recent studies have

revealed that it enhances the decomposition of organic composts like cow dung, poultry manure

and press mud. Trichoderma harzianum enhances the decomposition of compost. It changes the

colour of fresh cow dung in five days.

Trichoderma is capable of colonizing cow dung / farmyard manure (FYM) that serves as an

excellent substrate for its multiplication. It multiplies very well on cow dung /FYM not only under

laboratory condition but also at farmers’ level in their compost pits. The population of T. harzianum

on colonized cow dung may go as high as 2.46 x 1012 cfu.g-1 air-dried sample at 30% moisture

level and 320C temperature and two weeks of incubation. Exponential multiplication of

Trichoderma in cow dung is probably due to its versatile nature for carbon nutrient and major and

minor nutrients available during decomposition. Analysis of colonized compost showed that both

total and water soluble content of a number of macro and micronutrients like P, K, S, Zn, Cu and

Fe were significantly higher in T. harzianum colonized FYM as compared to non-colonized FYM.

There was almost 6 folds increase in water-soluble humic matter content in colonized FYM as

compared to non-colonized. Since humic matter is reported to have got growth promoting effect, in

addition to better availability of macro and micronutrients, higher humic matter content might also

be responsible for the better plant growth in Trichoderma harzianum colonized FYM.

Conclusion

When introduced to soil environment Trichoderma faces tough competition from other

microbes like fluorescent pseudomonads etc. Therefore, in order to fully harness its potential for

benefit of agriculture, there is need to support it even after application. One of the most effective

methods for the delivery of Trichoderma in soil is through colonized compost like FYM, cow dung;

poultry manure etc.


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Environmental Factors Influencing Ascospore Viability, Conidium Production, Dissemination, and Germination of V. inaequalis

K .P. Singh and J. Kumar

College of Forestry & Hill Agriculture, Ranichauri-249 199 (Uttarakhand)

Uttarakhand is predominantly a Horticultural State of India, since the economy of its

growers and orchardists largely depends upon the cultivation of fruits and vegetables. Ageo-

climatic conditions of the state are well suited for the production of different types of fruits ranging

from temperate to sub-tropical fruits. Apple cultivation in temperate fruit region of India has taken

an important position in fruit production. It rank 5th, first being mango followed by banana, citrus

and guava. In India, its cultivation of apple is mainly confined to the Western Himalayas covering

an area of 2,38,000 hectares with production of 1,320,590 metric tonnes. Kashmir valley has about

60,000 ha, Himachal Pradesh 47000 ha, Uttarakhand 32254 ha, Sikkim 800 ha and Arunachal

Pradesh 1802 ha under apple, beside unrecorded area in other hill regions. The main apple

varieties are ‘Royal Delicious, Golden Delicious, Red Gold, Tydeman’s-Early-Worcester, Red

Delicious, Rich-a-Red, Starkrimson Delicious, Top Red, Red Chief, William Favourite, Summer

Queen, Mcintosh, Red Fuji, Oregon spur, Crab apples, and Jonathan. The production, quality and

usage of the fruit are greatly influenced by the insect, pests and diseases. The diseases inflicting

injury partly or wholly to an apple tree are several. The most prominent among these are Apple

scab, Powdery mildew, Phytophthora root, Collar rot, Apple blotch, Canker, White root rot, Fly

speck, Sooty blotch, and Replant problem (Singh et. al. 2007). All the diseases combined did not

discourage the fruit growers to the extent as the one scavenger disease called “SCAB” did in a

couple of years. In Uttarakhand, control of apple scab is achieved primarily through a protectant

fungicides spray program. In a protectant program for primary scab control, fungicides are

generally applied after every 10 days of new growth. Applications are made regardless of whether

infection periods have occurred. In wet growing seasons, Gangotri fruit belt growers make up to

10-12 fungicides applications for scab control (Singh and Kumar 2005). To improve spraying

efficiency, with reduced fungicide use, more reliable scab warnings are needed. GBPUAT

established the effectiveness of the scab predictor for scheduling several EBI fungicides that have

post-infection control activity against apple scab. We have started experiments to study some of

the relevant epidemiologic questions related to apple scab management.

Installing an apple scab forcasting and monitoring system at Harsil, Purola-Naugaon, Koti-

Kanasar, Gwaldam and Joshimath and recorded weather parameters. A model to predict

ascospore maturity for use in Uttarakhand orchards. These model are designed to identify earliest

date of ascospores are matured and discharged. In Garhwal Himalayas, scabbed infected apple

leaves from unsprayed orchards of Red Delicious cultivars were collected periodically between 1st

week of March to June each year from 1995 to 2010. The ascospore maturity started around 2nd

week of March and continued upto last week of May at different place of Uttaranchal Himalayas.


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The ascospores can germinate and cause infection only when they are kept wet over a certain

minimum period of time, temperature ranging from 6-26°C. Production of conidia takes place over

a wide range of temperature from 4-28°C, sporulation peaks at 16-20°C. The conidia germinate at

temperature widely ranging from a minimum of 0°C to a maximum 32°C. Temperature during

spring favour pseudothecial development, maturity and discharge of ascospores, process of spore

germination and establishment of primary infection in the spring season. Intermittent wet and dry

periods are congenial for perithecial maturity and discharge of ascospores than the continuous wet

weather in early spring.

The dispersal of primary and secondary spores largely depends on air movement, during

the rainy periods in spring as well as throughout the growing season. Singh and Kumar (2010)

has revealed the wind dissemination of conidia in Gangotri valley and concluded that ascospores

discharge varied greatly with the prevailing meteorological condition. The trapped conidia of V.

inaequalis at 2500 m. asl. Height and postulated that air-borne spores were important

epidemiologically in establishing disease in scab free orchards. He also suggested that large

numbers of ascospores of V. inaequalis are discharged during afternoon than early morning. The

wetting of perithecia during light is more effective than in darkness, and more ascospores are

released from perithecia in warm and humid atmosphere. The conidial stage ordinarily remains

viable for not more than 15 days and direct sunshine even for 48 h is lethal for its survival. The

mycelia stromatic pad or cushion underneath the conidial stage appears to remain viable and can

initiate new infections with the onset of favourable weather. The summer spores are spread by

washing action of rain and not by the air current. Weather and climate influence the epidemic

development either by interacting with the pathogen or altering the host physiology. A good deal of

work has been done all over the world and also by this University through several sustained trials

at Ranichauri and elsewhere to understand the impact of this single factor. The mention of the role

of changing weather conditions in relation to epidemics influencing the two distinct stages of the

pathogen will perhaps be more appropriate for a better understanding of the scab disease

On examination of the primary infection period of 15 years data from Gangothri fruit belt,

some differences were observed between our results and Mills table developed by Mills (1944)

and Mills and La Plante (1951) for ascospores infection. Our result shows 5 to 8 light infection

periods occurred during each year in the month of March, April and May which could initiate the

primary infection and time required for symptom expression was 9 to14 days under prevailing

temperature condition. Whichever the infection time was more than precticted (1 to 4 days) as

mentioned in Mills table. Six to eight moderate infection periods were recorded in each month

during 1990-2010 and almost all indicated delay by a day in symptom expiration (1-3 days) in

orchard conditions. The third criteria as described by Mills was severe infection period, 2 to 5

infection periods were observed in most of the month at an average temperature (11.4 to 15.2 ºC)

and leaf wetness (23.4 to 27.2 hr) period and indicated 1 to 2 days delay in symptom expression.

This observation revealed 2 day (light infection), 1 day (moderate infection) and 1 day (severe


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infection) delay in symptom expression under orchard conditions. The regression analysis was

used to describe relationship between Mills infection criteria and our light, moderate and severe

infection period data of Uttarakhand for symptom appearance. In all the cases, the total variation

was high in low moderate and severe, infection curves.

The prevailing microclimatic conditions, topography and apple cultivars might be the

possible reasons for the delay of ascospore release and symptom development in Uttarakhand

Himalayas. Ascospore maturation data of ten consecutive years were pooled and plotted against

Celsius degree day accumulation from the date of first ascospore discharge of Garhwal hills.

Based on the results, two linear lines were developed, one for the use when the cumulative degree

days from 1 February to 15 May was < 657 and another for use when the cumulative degree-days

for these dates was > 657. Our results showed that 50 and 95 per cent ascospores matured after

418 and 792 cumulative degree days, respectively for the orchards situated at 1900-2200 m asl

(villages Auli, Syori, Koti-kanasar, Talwadi and Gwaldam) while for orchards situated at higher

elevation (i.e. > 2200 m; e.g. villages Harsil, Dharali, Jhalla, Sukhi and Auli) the cumulative

degree-days was > 1182 (95% ascospore maturity). The duration of ascospore discharge in the

field appeared to be longer and varied from place to place.

The scab development was monitored over 15 years in farmers’ fields from 1994 through

2010, the PAD varied from 2872 to 7, 26,852. All the variables showed highly positive correlation

with each others. PAD was high and there was no adverse effect of delaying the first spray till 14 th

day after the petal fall stage. At this time, the proportion of ascospore that was mature was very

low and the amount of foliage infection was also low. Two-three spray of EBI fungicide at the end

of primary infection inoculum season had no effect on scab development. As is evident in figure 3,

PAD was low, the first Mills infection period for the season occurred 13 days after petal fall. Fifteen

to eighteen infection period were recorded from last week of May to September, three sprays

during this period gave good control of disease compared to the unsprayed, and just one spray

reduced scab on the leaves to a great extent, and eliminated scab on the fruits during 1999 to

2001. The reason for this was probably due to winter and early springs are more mild and rainy in

the Himalayan range of Uttaranchal hills. The susceptible cultivars (Red, Royal and Golden

Delicious) also served as one of the reason for increase of inoculum under favoruable conditions.

However, the overall results of this study and of Holb and Heijne (2002) and MacHardy et al.

(1993) indicated that, the fungicide applications against apple scab can be omitted at the

beginning of the season and could be a good strategy for saving cost in integrated orchards if PAD

values are lower than 600 ascospores/ m2. Estimates of PAD are useful when comparing

management strategies or control treatments in several orchards. However, the results clearly

indicated that the PAD was not uniformly distributed in farmer’s apple orchard or other

management practice was applicable in one orchard but not in another orchard subjected to the

same weather conditions. Thus more reliable data would be obtained from managed orchard


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whether sanitation practices can be used effectively to lower the PAD and, as a consequence,

lower the fungicide dose. For this reason, reduction of primary inoculum sources could have a play

very important role in the improvement of effectiveness scab management of apple in Uttaranchal

Himalayas.

Scab predictive and warning service in Uttarakhand hills: Apple scab forewarning service

carried out under NATP, ICAR, UCOST and NAIP project is being followed in Uttarakhand hills.

Such forecasting, which usually begins in the early spring, predicts the time when initial disease

may develop and when the threat of primary scab is over, and helps the orchardists in efficient use

of spray chemicals. Ascospores emanating from the pseudothecia on the overwintered leaves in

the spring from the main primary inoculums in most of the apple growing regions of the world. The

maturity and discharge of these spores usually coincide with the pink bud to petal fall stage of the

tree. Ascospore dose measures the actual inoculums concentration in the orchard air at different

stages of host phenology and this is dependent on, (i) ascospore productivity and, (ii) factors that

influence spore release i.e. air temperature, light, time of days, climatic date, and leaf wetting by

rain/dew. Numbers of traps are available for monitoring of ascospores dose in the air. The

percentage of coloured spores increased week by week until about bloom to early petal fall stage

of ‘Delicious, cultivar and then diminished in Uttarakhand hills. Looking into 20 years data on tree

phenology at Garhwal hills, is confident of utilizing tree phonological stages in developing a

predictive equation for improving chemical control strategy.

In Uttarakhand, apple scab predictor and µMETOS were able to predict infection periods

correctly as tagged leaves showed new scab lesion accordingly. The Revised Mill’s Table indicate

the minimum number of hours of continuous wetting periods required for primary infection of apple

leaves by ascospores of Venturia inaequalis.. Some ascospores are discharged at night or rain

begins after sunset, so hours of leaf wetting should be computed from sunrise. For all other

events, times should be computed from start of rain (Singh, et. al. 2010).

Singh and Kumar (2009) developed a linear statistical model based on the accumulated

degree days from the maturation of ascospore and PAD. The development and computation of

mathematical models or predictive equations, and automatic monitoring of weather data for apple

scab, majority of the orchardists in Garhwal hills and several other places of India still rely on

initiating the first spray at green tip to early petal fall stage in spring, and following a 10 day spray

schedule thereafter till the primary scab season is over. The above information collected from

experimental sites on the infection period is passed on to the orchardists by blowing a

characteristic signaling, telephonic communication, SMS, local news paper, Govt. organization and

through personal contacts or messages flashed 4-5 times through “All India Radio, Nazibabad” on

the urgent need to undertake immediate spray or to reschedule already recommended spray

programme. Such forewarning has benefited the grower in minimizing damages due to scab and


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also reduce fungicide usage.

REFERENCES

1. Holb, I. and Heijne, B. 2002. Comparative study of Dutch and Hungarian environmentally friendly apple orchards on potential ascospore dose of apple scab. Journal of Agricultural Science 12: 31-6.

2. MacHardy, W.E., Gadoury, D.M. and Rosenberger, D.A. 1993. Delaying the onset of fungicide programs for control of apple scab in orchards of low potential ascospore dose of Venturia inaequalis. Plant Disease 77: 373-375

3. Mac Hardy, W.E. 1996. Apple Scab: Biology, Epidemiology and Management. 545 pp. Academic Press, APS St Paul Minnesota.

4. Singh, K.P. and Kumar, J. (2005). IPM of apple diseases. Techanical Bulletin, GBPUAT, CFHA 6: 1-48

5. Singh, K.P. and Kumar, J. (2008). Disease warning system for scab of apple: A field study. GBPUAT, CFHA 22: 1-18

6. Singh, K.P. and Kumar, J. (1999). Studies on ascospore maturity of Venturia inaequalis, the apple scab pathogen, in Central Himalayas of India. Journal of Mycology and Plant Pathology 29: 408 – 15.

7. Singh, K.P. and Kumar, J. (1999). Efficacy of different fungicidal spray schedules in combating apple scab severity in Uttar Pradesh Himalayas. Indian Phytopathology 52: 142 – 7.

8. Singh, K.P., Kumar, J. and Singh, H.B. (2001). Curative and protective action of ergosterol-biosynthesis inhibiting fungicides in relation to infection periods against apple scab in Uttaranchal Himalayas. Indian Journal of Plant Pathology 19: 34 - 38

9. Singh, K.P., and Kumar, J. (2009). Potential ascospore dose of apple scab fungus, Venturia inaequalis, from Indian Himalayas. Indian Journal of Agricultural Sciences 79: 184 - 189

10. Singh, K.P., Kumar, J. and Kumar, B. (2010). GBPUAT and apple disease research in the Gangotri valley region of India. In: Microbial diversity and plant disease management, 625p., Singh, K.P. and Shahi, D.K. (eds). VDM Verlag Dr. Muller GmbH & Co. KG, Germany/ USA/ U.K., pp 276-301.


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Carbon Sequestration: Bamboo-Mycorrhizae

A. Garg*, S. Das#, Y. P. Singh#, S. P. S. Rawat$ *Department of Environment Management, Forest Research Institute, University, Dehradun- 248 006

#Department of Forest Pathology, Forest Research Institute, Dehradun $Climate Change and Forest Influences Division, Forest Research Institute, Dehradun

Introduction

Copenhagen meet on climate change in 2009 brought out three key issues: 1) It raised

climate change to the highest level of government; 2) The Copenhagen Accord reflects a political

consensus on the long-term, global response to climate change; 3) The negotiations brought an

almost full set of decisions to implement rapid climate action near to completion (UNFCCC).

Current climate situation is bringing urgent issue of global climate change to the centre stage.

Climate warming or global warming is the increase in the average temperature of the earth's near-

surface air and oceans since the mid-20th century and its projected continuation. Global surface

temperature increased 0.74 ± 0.18 °C during the last century (IPCC, 2007). The term global

warming was coined in 1896 by the Swedish chemist, Svante August Arrhenius. The urban heat

island effect is estimated to account for about 0.002 °C of warming per decade since 1900

(Trenberth et al., 2007). An increase in global temperature will cause sea levels to rise and will

change the amount and pattern of precipitation, probably including expansion of subtropical

deserts (Reichler et al., 2007). The continuing retreat of glaciers, permafrost and sea ice is

expected, with warming being strongest in the Arctic. Other likely effects include increases in the

intensity of extreme weather events, species extinctions and changes in agricultural yields, more

virulent attacks of diseases and insect pests and vanishing habitats of plants and animals.

Now the question arises that what causes this climate change? One of the major reasons

for this climate change is the increase in the concentration of green house gases (GHG) in the

atmosphere. GHG are responsible for Green House Effect. The greenhouse effect is the process

by which absorption and emission of infrared radiation by gases in the atmosphere warm a

planet's lower atmosphere and surface. Naturally occurring greenhouse gases have a mean

warming effect of about 33 °C (IPCC, 2007). The major greenhouse gases are water vapour,

which causes about 36–70 percent of the greenhouse effect; carbon dioxide (CO2), which causes

9–26 percent; methane (CH4), which causes 4–9 percent; and ozone (O3), which causes 3–7

percent (Kiehl and Trenberth, 1997; Schmidt, 2005) and Nitrous oxide (N2O). Human activity since

the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere

leading to increased radiative forcing from CO2, methane, tropospheric ozone, CFCs and nitrous

oxide. The concentrations of CO2 and CH4 have increased by 36 and 148 percent respectively

since the mid-1700s (EPA, 2008). Carbon dioxide concentrations are continuing to rise due to

burning of fossil fuels and land-use change. About three-quarters of the increase in CO2 from

human activity have been produced by fossil fuel burning over the past 20 years. Most of the rest

is due to land-use change, particularly deforestation (IPCC, 2001).


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Through successively improved versions of general circulation models (GCMs), the

currently accepted estimate of the warming trend was about 3 ± 1.5 °C, for a 2 x CO2 scenario,

with regional temperature increases at mid- to high-latitudes possibly exceeding 10 °C (Overpeck,

1991). The IPCC Special Report on Emissions Scenarios gives a wide range of future CO2

scenarios, ranging from 541 to 970 ppm by the year 2100 (Prentice et al., 2001). New ice core

records show that the earth system has not experienced current atmospheric concentrations of

CO2, or indeed of CH4, for at least 650 kyr – six glacial-interglacial cycles. During that period the

atmospheric CO2 concentration remained between 180 ppm (glacial maxima) and 300 ppm (warm

interglacial periods; Siegenthaler et al., 2005). It is generally accepted that during glacial maxima,

the CO2 removed from the atmosphere was stored in the ocean. Several causal mechanisms have

been identified that connect astronomical changes, climate, CO2 and other greenhouse gases,

ocean circulation and temperature, biological productivity and nutrient supply and interaction with

ocean sediments.

As the population is swelling, its social, political and economical areas are expanding

accordingly and invading the very constant sphere of ecosystem. Human-induced climate change

has become a central theme and needs immediate response from each individual. Hence,

mitigation of green house gases has become a priority. The potential of nature to tackle elevated

CO2 cannot be ignored or underestimated. Exploring out the hidden mysteries of nature to mitigate

the carbon has become an essential need in today’s scientific world. Such a concept inspires us to

review and investigate the potential of Bamboo-Mycorrhiza as an efficient candidate in

sequestering the elevated carbon-dioxide.

Carbon Sequestration

Mitigation of global warming can be attained through reductions in the rate of

anthropogenic greenhouse gas release. To a great extent, mitigation of climate change is a matter

of understanding and manipulating the carbon cycle. Prior to the industrial revolution, the carbon

that is now floating in the atmosphere was locked permanently in large underground pools

(Schroeder and Ladd, 1991; Rubin et al., 1992). Presently, over 8 billion tons of C are added

annually to atmosphere. While retrieval of the extra C from the atmosphere is feasible, it may not

remain locked for too long in biomass. Instead, it will be passed through a chain of temporary

storage, finally returning to atmosphere. Current estimates are that, all together, plants retain

annually about 600 GtC (gigatons of carbon), with another 1600 GtC in soil (Herzog et al., 2000).

Under the Kyoto Protocol, industrialized countries have promised to reduce their carbon emission

to below their 1990 emission levels over the period 2008-2012. To fulfill their commitment, some

countries have proposed the inclusion of three broad land management activities pursuant to

Article 3.4 of the Protocol, including forest, cropland and grazing land management. These

activities can reduce atmospheric carbon stock by sequestering, or removing, carbon from the

atmosphere and storing it in soil or biomass (Feng et al., 2000). Carbon sequestration contributes

to offset the greenhouse effect and thus, reduce the pace of global warming. Models suggest that


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mitigation can quickly begin to slow global warming, but that temperatures will appreciably

decrease only after several centuries (Lowe et al., 2009).

Carbon sequestration is the long term storage of carbon in oceans, soils, vegetation

(especially forests) and geologic formations (Ecological Society of America, 2000). The first large-

scale CO2 sequestration project (1996) is called Sleipner, and is located in the North Sea where

Norway's state oil hydro removes carbon dioxide from natural gas with amine solvents and

disposes this carbon dioxide in a deep saline aquifer. In 2000, a coal-fueled synthetic natural gas

plant in Beulah, North Dakota, became the world's first coal using plant to capture and store

carbon dioxide (Petroleum Technology Research Centre, 2009). Ocean processes regulate the

uptake, storage and release of CO2 to the atmosphere. Seawater can, through inorganic

processes, absorb large amounts of CO2 from the atmosphere, because CO2 is a weakly acidic

gas and the minerals dissolved in the ocean have over geologic time created a slightly alkaline

ocean. Carbon dioxide sequestration in geologic formations includes use of site such as depleted

oil and gas reservoirs, shale formations with high organic content, unmineable coal seams and

underground saline formations. Immense quantity (about 65 × 106 GtC) of carbon stored as

carbonate rocks.

Fig.1. Simplified representation of the Global Carbon Cycle. (Source: IPCC, 2001).

Carbon sequestration in terrestrial ecosystems is either the net removal of CO2 from the

atmosphere, or the prevention of CO2 emissions from the terrestrial ecosystems into the

atmosphere (Fig.1). Two, among the most important sinks for C in the terrestrial ecosystem, are

the biosphere and the pedosphere. The potential of the pedosphere to sequester C can play an


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important role in the overall management of C (Schlesinger, 1990; Goudriaan, 1995; Paul et al.,

1997; Potter and Klooster, 1997; Trumbore, 1997; Lal et al., 1998; Lal, 1999; Marland and

Schlamadinger, 1999; Rosenberg et al., 1999; Rosenzweig and Hillel, 2000). The C in soil is a

balance of inputs and outputs. Increasing inputs (i.e. increasing plant growth) or decreasing

outputs or losses of C result in increasing soil C, called soil C sequestration or building C ‘sinks’.

The amount of C that is stored in soils is a function of climate, precipitation and temperature and

soil properties, principally clay content (Rice et al., 2007).

Plants and Carbon Sequestration

In terrestrial carbon sequestration, vegetation plays a major role. Plants remove CO2 from

the air and convert it into sugars that are used to produce substances needed to sustain their

growth and development. Many of these CO2-derived products, particularly lignin and cellulose,

are present in large quantities within the woody tissues of trees and shrubs. Hence, as long as

these plants are alive and growing, they actively remove carbon from the air around them. Even

after their biological activities cease, trees continue to retain the carbon they sequestered during

their lifetimes within their woody tissues. Thus, trees and other woody plants, aided by human

ingenuity, possess an enormous potential to sequester vast amounts of carbon for very long

periods of time (Chambers et al., 1998). The ability to remove CO2 by trees from the air grow

stronger as the air's CO2 content continues to rise, due to the well-known aerial fertilization effect

of atmospheric CO2 enrichment.

Plants assimilate carbon through the process of photosynthesis and return some of it to the

atmosphere through respiration. The carbon is added to the soil as litter when plants die and

decompose. Litter from plants grown at elevated CO2 concentrations often decomposes at a

slower rate, or to a lesser degree, than litter from plants grown at the air's current CO2

concentration. This phenomenon results in greater carbon retention times within decaying litter;

and it provides greater time for more of the litter's carbon to become incorporated into more stable

compounds that can be sequestered for longer periods of time within soils. And, of course, it

leaves a greater amount of carbon to be thus sequestered. For example, atmospheric CO2

enrichment significantly reduced litter decomposition rates in an alpine grassland species (Hirschel

et al., 1997), in seedlings of yellow poplar (Scherzel et al., 1998) and in sorghum and soybeans

(Torbert et al., 1998). Likewise, Van Ginkel and Gorissen (1998) grew this same perennial

ryegrass at 700 ppm CO2 and noted a 42 percent increase in both root and soil microbial biomass,

while root decomposition rates dropped by 13 percent relative to those measured at 350 ppm CO2.

The carbon is stored in the soil is as soil organic matter (SOM, 57% by weight). SOM is a complex

mixture of carbon compounds consisting of decomposing plant and animal tissue, microbes

(protozoa, nematodes, fungi and bacteria) and carbon associated with soil minerals. There is a

good correlation between soil aggregate stability and soil organic matter content across a wide

range of soil types, suggesting that whatever enhances soil stability will enhance the likelihood that

carbon delivered to the soil as a consequence of plant growth and decay will stay sequestered


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there for the longest time possible (Swift, 2001). Bamboo forest biomass stores a large quantity of

carbon. With a carbon percentage of 40-45 per cent, nearly half of the total biomass is carbon.

This makes them an efficient candidate in carbon sequestration.

Role of Bamboo in Carbon Sequestration

Bamboo is woody grass belonging to the sub-family Bambusoideae of the family Poacae.

There are approximately 1,500 spp. under 87 genera of bamboo worldwide (Ohrnberger, 1999; Li

and Kobayashi, 2004). Bamboo is known to be one of the fastest growing plants in the world, with

a growth rate ranging from 30-100 cm per day in growing season. Bamboo is naturally distributed

in the tropical and subtropical belt between approximately 46° north and 47° south latitude, and is

commonly found in Africa, Asia and Central and South America. Some species may also grow

successfully in mild temperate zones in Europe and North America. Bamboo is an extremely

diverse plant, which easily adapts to different climatic and soil conditions. Dwarf bamboo species

grow to only a few centimeters (cm), while medium-sized bamboo species may reach a few meters

(m) and giant bamboo species grow to about 30 m with a diameter of up to 30 cm. Bamboo stems

are generally hard and vigorous, and the plant can survive and recover after severe calamities,

catastrophes and damage. Bamboo can form a closely woven mat of roots and rhizomes

underground, which are effective in holding soil. The soil around bamboo plants is permeated by a

mass of intertwining roots (Ben-zhi et al., 2005). Bamboos have the advantage of fixing carbon in

rhizomes, which do not die at harvest, as tree roots do—which means that the below-ground

biomass sequestration is stable and must not be subtracted after harvest. Furthermore, some

species may fix much more carbon in their culms at harvestable age than in the leaf or branch

biomass of tree species.

In the terrestrial ecosystem, forest is the largest carbon inventory and it deposits 1,146 x

1015 g carbon that occupies 56 percent of the carbon inventory of the total terrestrial ecosystem.

Bamboo ecosystem is an important part of forest ecosystem and an important carbon source and

carbon sinks on the earth. Bamboo accumulates biomass quickly and offers the opportunity to

maintain and increase carbon stocks through carbon sequestration (one hectare of bamboo forest

can absorb 17 metric tons of carbon/year). In this system, bamboo biomass, bamboo litter and

bamboo soil are carbon sinks on the earth. In bamboo ecosystem, through the mechanism of

photosynthesis, bamboo, turn carbon dioxide into organic carbon and stores it as their structures.

Part of organic carbon will store in the litters and forest soil and part of which will gradually

decompose, rot and return to the atmosphere (Rh). The Net Primary Production (NPP) of bamboo

forest may be formulated as: NPP = Gp - Ra – Rh. Gross of plant (Gp) and respiration of plant

(Ra) will emit part of its carbon. In the natural situation, the Net Primary Production of bamboo

forest is positive, but due to the disturbance by human beings, NPP is negative. So, we must take

measures to protect the bamboo forest from being a carbon source and to mitigate the

greenhouse effects through carbon storage and emission from bamboo stands, litters, bamboo

forest soil and bamboo products. The bamboo ecosystem participates in the carbon cycle between


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bamboo forest and atmosphere. Bamboo forest biomass stores a large quantity of carbon. With a

carbon percentage of 40 – 45 percent, nearly half of the total biomass is carbon. Bamboo

represents one of the world’s greatest natural and renewable resources. Moreover, bamboos are

mycotrophic (dependent on mycorrhiza) due to their fast rate of growth and shallow root system

(Rawat, 2005). The dynamic role of microbes in C cycle in soil of bamboo can’t be underestimated.

Microbes and Carbon Sequestration

In soil, there is a great role of microorganisms in carbon sequestration. Microbes are

responsible for transforming many of earth’s most abundant compounds and cannot be ignored in

the search for scientific solutions to adverse global changes both the ubiquity of microbes and the

delicacy of environmental balances contribute to the planet’s sensitivity to disturbances in the

microbial world.

Microbes, cycle immense volumes of carbon in the process of recycling most of earth’s

biomass: They can fix CO2 by light driven (photoautotrophy) and geochemically driven

(lithoautotrophy) reactions, generate methane, produce CO2 as they decompose organic matter,

precipitate carbonate minerals and catalyze the polymerization of plant polymers into recalcitrant

pools of carbon in soil (Fig.2). Some microbial populations influence carbon storage in plants by

enhancing their growth through interactions with organic compounds around the root

(rhizosphere), by providing nutrients such as phosphorous and nitrogen or by suppressing plant

pathogens in the soil. Other microbial communities exert neutral or even harmful effects.

Fig.2. Carbon transformation and transport in soil (Source: The U.S. Climate Change Science Program: Vision for the Program and Highlights of the Scientific Strategic Plan, 2003).


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Soils have a finite capacity to sequester organic carbon (OC) that is determined by soil

texture and aggregation. SOC levels increase with silt + clay content and the maximum level is

achieved when soils are most highly aggregated, i.e. when they are not tilled (Duxbury, 2005).

Worldwide, SOC in the top 1 meter of soil comprises about 3/4 of the earth's terrestrial carbon

(Umadevi & Thiyagarajan, 2007). Soil organic and inorganic carbon (C) is by far the largest

terrestrial C pool, storing more than double the quantity of C in vegetation or the atmosphere

(Batjes, 1996; Eswaran et al., 2000). Changes in soil organic and inorganic C content could have a

great effect on the global C budget. Historically, the soil C pool has been a major source of

atmospheric abundance of CO2, contributing as much as 78 ± 12 Pg of C, and likely more. Such a

transfer of soil C to the atmospheric pool has created a C deficit in world soils, the so-called ‘C

sink.’ The process of transfer of atmospheric CO2 into the soil C pool, either through humification

of photosynthetic biomass or formation of secondary carbonates, is termed soil C sequestration.

The rate of soil C sequestration ranges from about 100 to 1,000 kg ha−1 yr−1 for soil organic C and

5 to 15 kg ha−1 yr−1 for soil inorganic C, depending on land use, soil properties, landscape position,

climate and cropping/farming systems. Total global C sink capacity, approximately equal to the

historic C loss of 78 ± 12 Pg, can be filled at the potential maximum rate of about 1 Pg C yr−1 (Lal

& Follett, 2009). Moreover, a potential increase in the C storage capacity of soil is a recognized

option for mitigating the buildup of atmospheric CO2 in the future (Watson et al., 2000; Lal and

Kimble, 2000).

Role of Bamboo-Mycorrhizae in Carbon Sequestration

In the terrestrial ecosystem, forest is the largest carbon inventory and it deposits 1146 x

1015 g carbon, which occupies 56 percent of the carbon inventory of the total terrestrial ecosystem.

And also bamboo forest biomass stores a large quantity of carbon with a carbon percentage of 40

-45 per cent, nearly half of the total biomass is carbon. Bamboo ecosystem is an important part of

forest ecosystem and act as an important carbon source and carbon sinks on the earth. In this

system, bamboo biomass, bamboo litter and bamboo soil are the major part in carbon sinks

(www.bamboocarboncredits.com, 2009) Moreover, plants with high growth rate and shallow root

system may be more mycotrophic like bamboos.

As a general trend, a large proportion of the additionally fixed carbon in terrestrial

ecosystems is channeled below ground, to roots (Rogers et al., 1994) and soil (Jones et al., 1998).

Soil micro-organisms, especially arbuscular mycorrhizal fungi (AMF) in addition to ectomycorrhizal

fungi (ECM) and ericoid mycorrhizal fungi (ERM) have well-recognized roles in terrestrial

ecosystems (Zhu and Miller 2003; Read et al., 2004; Rillig, 2004; Rillig and Mummey, 2006).

Arbuscular mycorrhizae (AM), ubiquitous mutualistic symbioses between the roots of the vast

majority of land plants (80%; Allen, 1991) and fungi in the Glomeromycota, are an important factor

to consider in attempts to understand the effects of elevated atmospheric CO2 on plants and

ecosystems (Hodge, 1996; Rillig and Allen, 1999; Fitter et al., 2000; Treseder and Allen, 2000;

Rillig et al., 2002).


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The arbuscular mycorrhizal symbiosis is ideal for two main reasons. First, AMF are

affected indirectly by elevated atmospheric [CO2], responding to changes in plant physiology and

growth (Staddon et al., 1998; Rillig et al., 2002; Treseder, 2004). These fungi are obligate

biotrophs that are intimately associated with plant roots and depend directly on plant

photosynthate as a source of carbon (Allen, 1991; Smith & Read, 1997). Increasing atmospheric

CO2 often results in increased allocation of carbon to roots. This increased carbon availability can

influence microbial interactions in the rhizosphere and the structure of the AMF community

(Klironomos et al., 1998; Wolf et al., 2003). Second, AMF and many of their plant hosts grow and

reproduce quickly. This allows us to study the responses of several generations over a reasonably

short period of time. AM is not always best represented as a ‘dual organism’ that can be studied as

an entity, but as a suite of plants and fungi whose organization is spatiotemporally complex,

transient and extensive (Rillig & Allen, 1999).

Fig.3. Framework for the discussion of arbuscular mycorrhizal (AM) fungal contributions to

responses to elevated atmospheric CO2 at the levels of individual host plant, plant

population, plant community and the ecosystem. ‘Ecosystem’ as defined here belongs to the

process-functional branch, and ‘community’ to the ‘population-community’ branch of the hierarchy

(see text). The bold arrows signify the different ways in which AM fungi can influence CO2

responses at the respective levels (Rillig & Allen, 1999).

The ways in which mycorrhizal fungi can potentially influence responses to CO2 at the

various levels include: (a) influencing the homeostatic adjustment of individual host plants to

elevated CO2, (b) altering the variability of responses to CO2 within a plant population, (c)

differentially responding and providing feedbacks to different plant species within a plant

community and to different plant functional assemblages in an ecosystem, (d) providing an


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increased ecosystem sink of carbon in the soil, and influencing nutrient cycling patterns. For

example, because ‘community’ and ‘ecosystem’ belong to different hierarchies, it follows that

changes in plant community composition mediated by AM fungi do not necessarily have to lead to

ecosystem changes and vice versa. It is necessary to consider which response variables are most

meaningful at each level of organization (MacMahon et al., 1978; Fig.3). For example, percent root

infection by AM fungi may yield desirable information for studying P uptake in an individual plant

(Smith & Read, 1997). However, percent infection may be a less important measure of ecosystem

soil carbon storage, for which AM extraradical hyphal length, biomass or glomalin turnover may be

more crucial. AM fungi can constitute a physiologically important carbon sink (Wright et al., 1998).

Roots with AM fungi receive about 4–20 percent more photosynthate than comparable non-

mycorrhizal (NM) roots (Smith and Read, 1997). Jakobsen and Rosendahl (1990) estimated that

AM fungi could use up to 20 percent of the total fixed CO2 in young plants. The importance of this

sink to plants grown in elevated CO2 has been recognized (Jongen et al., 1996).

It has been hypothesized that AM fungi can take up host extra carbon before it is

rhizodeposited and available to all rhizosphere inhabitants (Diaz et al., 1993; Diaz, 1996). AM

fungal inoculum potential (Koide and Mooney, 1987; Allen, 1991) and AM fungal species are non-

uniformly distributed in the environment, even on a local scale of a few square meters (Bever et

al., 1996). This means that plants from the same population can have quantitatively (percent

infection) and qualitatively (subset of the AM fungal community) different AM fungal root

colonization.

AM hyphae are not involved in litter decomposition processes, but they take up nutrients

(including nitrogen) and translocate them to the plant root. High AM fungus biomass may

therefore, impose nutrient limitations on decomposer fungi in nutrient-limited ecosystems (Allen,

1991). So far, only ectomycorrhizal fungi have been postulated to suppress decomposition by this

mechanism (Gadgil and Gadgil, 1971; Zhu and Ehrenfeld, 1996). It is not known whether AM fungi

can inhibit decomposition in similar ways, and whether this effect can be magnified by elevated

CO2. In case AM fungi prove to be important in this context, they would modify carbon cycling and

retard the release of CO2 back to the atmosphere, thereby, increasing the system carbon sink.

Among the fungi, arbuscular mycorrhizal fungi (AMF) appear to be the most important

mediators of soil aggregation for three reasons. The extraradical hyphae of AMF represent a

substantial often dominant component of soil microbial biomass (Allen, 1991; Miller et al., 1995;

Rillig et al., 1999). By directly tapping into carbon resources of the plant, they are independent of

the limiting carbon supply in bulk soil on which saprobic fungi depend (Smith and Read, 1997).

Additionally, since grazers prefer saprobic hyphae over AMF hyphae (Klironomos and Kendrick,

1996), AMF hyphae appear to have a longer residence time in soil, allowing for a less transient

contribution to soil aggregate stabilization than saprobic hyphae.

At the ecosystem scale, AMF become important through their effects on soil aggregation in

soils in which organic matter is the main binding agent. Soil aggregation, in turn, has important


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consequences for soil carbon storage (for example, via physical protection of carbon inside of

aggregates; Jastrow, 1996; Six et al., 2000). Soil organic matter is of great significance in

determining or influencing numerous aspects of soil quality, including nutrient storage capacity and

water-holding capacity (Paul and Clark, 1989). Thus, AMF are not only a factor but also key

determinants of soil quality.

Glomalin: Link between AMF and Carbon Sequestration

Recently, a new factor of presumably great importance in soil aggregation was discovered:

glomalin (Wright and Upadhyaya, 1996). Glomalin is a glycoprotein produced by AMF and its

concentration in aggregates (Wright and Upadhyaya, 1998) and soil (Rillig et al., 2001 a&b)

correlates with the percentage of water-stable aggregates (WSA). Glomalin accounts for a large

amount (about 15 to 20%) of the organic carbon in undisturbed soils. The study of glomalin started

out with a monoclonal antibody (MAb32B11) raised against an unknown epitope on crushed

spores of the AMF species Glomus intraradices Schenck & Smith (Wright and Upadhyaya 1996;

Wright et al., 1996). This monoclonal antibody reaction has been used to operationally define

glomalin (Fig.4).

Fig.4. Various lines of evidence suggest that GRSP in soil is of arbuscular mycorrhizal fungal

origin (Source: Rillig, 2004).

There is increasing circumstantial evidence accumulating from decomposition studies that

Glomalin Related Soil Protein (GRSP) is of AMF origin. When AMF growth is eliminated, e.g., by

incubating soil without host plants, it was observed that GRSP concentrations decline, along with

AMF hyphae (Steinberg and Rillig, 2003).

Glomalin is an important molecule in aggregate stabilization. When aggregates are not

stabilized, they break apart with rainfall. Organic matter and nutrients within disrupted aggregates

may be lost to rain and wind erosion. The chemistry of glomalin makes it an ideal stabilizing coat.

The aggregation reduces wind and water erosion, increases water infiltration, increases water

retention near roots, improves nutrient cycling, and improves root penetration by reducing


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compaction along with soil carbon and/or nitrogen storage.

Consequences of Increased Levels of CO2 for Microbial Communities in the Rhizosphere

Soil microorganisms are commonly C-limited. Therefore, increased C availability due to

enhance rhizodeposition, resulting from increased level of atmospheric CO2 concentrations, might

stimulate microbial growth and activity. However, studies examining effects of elevated CO2

concentrations on microbial biomass, particularly in the rhizosphere, have yielded mixed results.

Alterations in carbon supply have been shown to decrease (Diaz et al., 1993; Ebersberger et al.,

2004), increase (Zak et al., 1993) or not affect (Randlett et al., 1996; Kandeler et al., 1998) on the

growth and activities (e.g. decomposition and nutrient cycling) of soil-borne communities (Jones et

al., 1998; Hu et al., 1999).

Under elevated CO2, increased photosynthate supply stimulated mycorrhizae growth and it

could enhance plant growth in the way of increased nutrient supply. Compared with non-

mycorrhizal plants, there is more carbon translocated to root in mycorrhizal plants. Elevated CO2

stimulated photosynthetic carbon fixation and allocation of carbon to nodule may also increase.

Elevated CO2 may affect allocation of carbon in soil and ecosystems through changing

carbohydrates amount and composition in plants. Root morphological and physiological

characteristics were changed under CO2 enrichment. Since CO2 concentration in soil is about 50

times higher than that in atmosphere, effect of CO2 elevation on rhizosphere soil processes may

not be direct. However, if rhizodeposition increased with elevated CO2, it is possible that the

structure and composition of microbial community will change. This includes changes of microbial

amount and activity, population dynamic, etc. Any change in size and composition of soil microbial

community will probably affect soil evolvement and nutrients availability of plant and its symbionts.

Analyses of variation partitioning for bacterial, fungal and nematode community profiles

revealed that the bacterial community structure was the most affected by elevated CO2, with fungal

and nematode communities being influenced to a somewhat lesser extent. The factors most

influencing fungal community structures were soil origin and plant species. Moreover, the

response of the rhizosphere communities to elevated CO2 depended on the plant species. The

mycorrhizal plant, Festuca rubra, showed a strong increase in AMF infection under elevated CO2

and a more pronounced effect of elevated CO2 on the structure of the rhizosphere microbial

community. This suggests that mycelial products, potentially coupled with altered root exudation

patterns, may have an important impact on the size and structure of the soil microbial community

in response to elevated CO2.

Limitations of Terrestrial Carbon Sequestration

Soil C loss occurs through biological (soil respiration) as well as physical (leaching and soil

erosion) processes. On a global basis, soil respiration is believed to be the main C loss pathway.

The microbial biomass that plays a major role in transforming inputs of organic matter also controls

C loss. The field measurements of soil respiration in dryland agroecosystems show wide variations

due to seasons as well as types of soil amendments. Thus, apart from the controlling effect of


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environmental variables (principally temperature and soil moisture), the rates of soil respiration are

strongly affected by various management practices. It is important to understand the processes

controlling soil respiration rates in order to devise strategies for effective C sequestration.

Appropriate land management can contribute significantly to soil C sequestration by

manipulating agroecosystems, forestry and agriculture practices to generate greater biological

inputs of C than losses. Farming practices since ancient days have improvised procedures that

enhance soil fertility by increasing the input of plant materials (e.g. shifting cultivation where

cultivation is alternated with forest regeneration and growth). Precise estimates of C input and loss

from soil provide the capability to quantify in short terms changes in soil organic C storage

resulting from a specific land use change; such critical methodology may become increasingly

important in relative assessment of the different land use change options with respect to C

sequestration. Quantifying the effects of management practices and their combinations on C

sequestration is vital for improving the potential of farming systems to sequester C (Singh and

Ghoshal, 2007).

The capacity of the land-based sink is progressively decreasing in proportion to total emissions

(Canadell et al., 2007), probably due to gradual increase in extent and severity of soil degradation. Incidents

like forest fire, soil erosion, felling of trees, forest land disturbances due to constructions of dams, roads, etc.

often make the land fragile to sequester carbon for longer duration. Such disturbance also affects the soil

microbial diversity, which indirectly reduces the ability of soil to act as carbon sink.

Not all environmental effects of bamboo are beneficial or benign. Monopodial bamboos can

be invasive to the extent that tough root barriers are needed to prevent undesirable spreading.

Bamboos have caused slope failures due to dense root mats in upper soil horizons (Dura and

Hiura, 2006; Lu et al., 2007). They may emit methane or isoprene and contribute directly or

indirectly to warming.

To mitigate atmospheric carbon-dioxide is becoming an essential requirement at present

scenario. Implementation of new policies in the area of forest management, afforestration, land

management and soil conservation will boost the terrestrial carbon sequestration. The ability of soil

microbes and their role in carbon sequestration needs further research. The role of glomalin

produced by arbuscular mycorrhizal fungi in soil aggregation and ability of phytoliths (plant

stones) produced by bamboo to trap soil carbon for longer period in soils needed special attention

to enhance the capacity of terrestrial carbon sequestration (Parr and Sullivan, 2004).

Conclusion

No matter what has happened to the Kyoto Protocol, may be Copenhagen meet was highly

criticized, Himalayan glaciers won’t melt by 2035 or IPCC report might be challenged, all these

issues will never allow us to close our eyes from the harsh realities of climate change. We need to

believe that our atmosphere is changing- uneven climate patterns will draw us to the cliff of

alarming situation of global warming. GHG have to be mitigated to the possible extent by strict

actions. Our functional role should involve implementation of new approaches to improve carbon


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absorption of vegetation and soil, to reduce the emission of carbon, to enhance the Soil Organic

Matter (SOC) and to extend the storage time of carbon in soil.

Quick biomass accumulating nature of bamboos enables to trap carbon for longer period

and after death bamboos leave behind phytoliths or plant-stones in soil, which hold carbon in silica

crystals for very long period. Mycotrophic nature of bamboos helps in maintaining the soil carbon

and their glomalin plays a very important role in soil aggregation that traps the carbon in it. Also,

the efficient role of soil microbes in carbon cycle cannot be neglected. The amount of

sequestration depends on land-management practices, edaphic factors, climate and the amount

and quality of plant and microbial inputs. These situations provide valuable tools for addressing

many issues related to carbon sequestration in both natural and agricultural soils. Carbon

sequestration, in turn, will contribute in reducing atmospheric CO2 concentration and mitigate

drought, salinity stress and desertification. Thus, synergistic role of bamboo-mycorrhizae will

certainly be the one of the viable approaches towards sustainable forestry.

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Plant Healthcare for Resource Poor Farmers – Technologies for Disease Management in Low Input Systems

J. Kumar

Department of Plant Pathology, GBPUA&T, Pantnagar-263 145 (Uttarakhand)

Since recorded history, the impact of pests on different crops has been important as a

result of which many practices of “traditional” and “modern” agriculture have evolved. During the

last century high input based intensification of agricultural production and less diversified farming

systems has caused crop protection problems to multiply. As a result an impressive array of crop

protection technologies such as pest-resistant plants, cultural controls, biological controls,

pesticides, behavior-modifying substances, quarantine laws, and pest eradication programs have

evolved. Ancient farmers developed sustainable agriculture practices, which allowed them to

produce food and fibre for thousand of years with few outside inputs. Most of such practices were

developed empirically through millennia of trial and errors, natural selection, and keen

observations. Some of these practices which often conserve energy, maintain natural resources

and reduce chemical use, deserve examination. Today, perhaps over half the world’s arable land

is farmed by traditional farmers. Many of their techniques are unknown or poorly understood, but

have allowed them to produce crops and animals with minimal or no purchased inputs. The

striking diversity existing in the traditional farming systems gives them a high degree of stability,

resilience and efficiency especially on marginal lands.

Efforts to intensify agriculture production will continue as a result of the need for food

security among rapidly growing population. But changes in agricultural systems and in the intensity

of land use have impacts on pest problems. Growing food demand must be met primarily by

increasing production on land already under cultivation (productive and marginal lands) and by

reducing losses due to diseases and pests. Attention, therefore, must go to small and marginal

farmers, who till nearly 65% of world’s arable land, to increase farm productivity. Crop protection

aspects must accordingly be incorporated as an integral part of sustainable efforts to intensify

production.

Plant protection in hill agriculture

Rainfed farming and intensive cultivation on small and fragmented lands is characteristic of

hill agriculture. Less land per person requires more high yielding agriculture and often the

response is high levels of chemical inputs, reduced rotations and extensive monocultures. The

search for greater and ever-cheaper production with increased intensification reduces the

biodiversity of the system itself and makes it vulnerable (Box 1).


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Decreased biodiversity tends to result in agroecosystems that are unstable and prone to

recurrent pest outbreaks and many other problems. In a recent study¥ (Singh and Singh, 2005)

carried out in four hill districts of Uttarakhand, viz., Bageshwar (Kumaon), Nainital (Kumaon),

Uttarkashi (Garhwal) and Pauri Garhwal (Garhwal), it was found that the per hectare

agrochemical usage in the vegetable crops was quite high as compared to cereal crops. The

highest per ha consumption was recorded in tomato, which stood at 406 kg/ha of fertilizers and an

average five sprays of pesticides. Similarly in other vegetables, the agrochemical (including

pesticides) consumption has dramatically increased and will continue in future as well.

High pesticide use does not guarantee pest control. Unaware of the problems arising from

pesticide resistance and the destruction of natural enemies, farmers often respond to pest

outbreaks by applying more pesticide, which merely aggravate the problem, a situation known as

‘the pesticide treadmill’. Once on the treadmill, the farmers find himself or herself facing spiraling

pesticide input costs, potentially increased pest problems and lower yields, leading to increasingly

smaller returns on investment. To increase yield from existing land requires good crop protection

against losses before and after harvesting, which, must be achieved within the framework of

Integrated Pest Management (IPM). However, the underlying, well taken theme--that an IPM

approach can lead to reduced reliance on pesticides--has to compete with constraints such as

intensive agriculture on small and scattered holdings, poor risk bearing capacity of the farmers,

inherent susceptibility of vegetable varieties in use to a spectrum of diseases and pests and

natural calamities (like draught or incessant rains).

Integrated Pest Management

Integrated pest management (IPM) is a concept of crop production incorporating effective,

ChallengesSmall and fragmented holding; women based hill agricultureSmall and fragmented holding; women based hill agriculture

Tremendous pressure to make living from the landTremendous pressure to make living from the land

Intensive Intensive agricultureagriculture

Reduced Reduced rotationsrotations

Extensive Extensive monoculturemonoculture

ReducedReducedBiodiversity of Biodiversity of

systemsystem

Box 1


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stable, long-lasting crop protection components that minimize the negative side effects of current

pest control actions. IPM recognizes that farmers' knowledge - and not just the technology - is the

key to success. It thus takes its place in a broad school of sustainable approaches, ranging from

organic agriculture to low external-input practices. In the traditional sense, IPM has been thought

of to be the use of multiple tactics to optimize control, but slowly that vision has changed to

accommodate the integration of all pest management tactics for a crop (Box 2). Pesticides are the

option of last resort in IPM programs because of their potential negative impacts on the

environment. If chemical pesticides must be used, it is to the grower’s advantage to choose the

least-toxic pesticide that will control the pest but not harm non-target organisms such as birds, fish,

and mammals. Pesticides that are short-lived or act on one or a few specific organisms are

included in this category. More recently, a larger portion of strategies utilized in agriculture have

been biological control practices progressing towards biointenssive IPM (Box 3). The goal is to

increase farmers’ income and to ensure that it can be sustained over time, and to reduce

environmental and health risks.

IPM is especially well suited to small scale farming because it makes use of on-farm labour

and farmers’ knowledge instead of purchased inputs. If deliberate attempts are made to

strengthen the natural defenses of the ecosystem, it is likely that there will be little or no need of

chemical inputs to manage pests. Promoting improved and promising IPM strategies that can be

easily understood and implemented by small scale farmers thus remains the major objective under

two situations: one involving traditional cultivation system and subsistence crops where pests

regularly cause considerable crop losses and the other involving pesticide induced crises caused

by high-input biased intensification, where farmers are continually forced to increase the amount of

pesticides they use in order to maintain yield levels. Both the situations need to be targeted in

order to implement an IPM programme in Uttarakhand hills.

A Common Minimum Programme under IPM : a case study in Uttarakhand hills

Off-season vegetable cultivation plays a unique role in the hill farming system in

Box-2

IPM Interventions

Pesticides Biological control Physical/mechanical control

Cultural/ sanitation practices

IPM Continuum Biointensive

Biologically based control

Prevention

Reduced risk pesticides

Economic thresholds

Monitoring

Chemically intensive

Box-3


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Uttarakhand. Being low volume and high value crops they are rated to be potential cash earners.

Unfortunately, however, all these cash crops suffer recurrent chronic losses due to a variety of

seed and soil borne diseases and impact of insects like, white grub and cutworm. Farmers suffer

from limited choice of improved cultivars and have poor access to healthy seeds and propagation

material. These problems result in an injudicious use of pesticides to solve pest problems causing

a number of problems related to heavy use of pesticides, like residues in soil, ground water and

harvested produce, intoxication of farmers and development of pesticide resistance.

The problems faced by the farmers in the region are consistent with mandate of IPM. The

challenge is to apply research to issues that lead to insecurity amongst small and marginal farmers

as regards crop management and protection. While threats with regard to biotic and abiotic

causes vary from region to region, there is a range of common challenges such as recurrent

losses (over 70%) to vegetable cultivation due to seed and soil borne pathogens and pests that

warrant a regional approach of integrated management (Box 4).

The cost of soil borne pathogens and pests to society and the environment far exceeds the

direct costs to growers and consumers. Long term chemical applications may permanently alter

the microbial community structure to an extent that sustainable agriculture may be impossible.

The opportunity therefore exists to address the issues relating to IPM across ecosystems through

a Common Minimum Programme¥. Other specific problems could be addressed through

supplementary intervention(s).

The key elements of the Common Minimum Programme that provide the frame work for a

regional approach include soil solarization, vermicompsoting, use of bioagents, and value

addition of vermicompost. Each element has a strong ecological base and operates through

COMMON THREATS TO VEGETABLES IN UTTARAKHAND HILLS

Crop Threat

Potato Late blight, bacterial wilt, brown rot, cut worm, white grub

Pea Seed rot, Root rot complex, Ascochyta blight, cut worm

Bean Seed rot, Root rot complex, anthracnose, angular leaf spot

Cabbage Seed rot, Root rot complex, collar rot, black rot, head rot

Cauliflower Root rot complex, collar rot, black rot, head rot

Capsicum Root rot complex, fruit rot, Cercospora leaf spot, dieback

Tomato Seed rot, Root rot complex, early blight, fruit rot, wilt, fruit borer

Cucumber Root rot complex, Bacterial wilt

Common threats indicated in italics are those that either seed or soil borne in nature and cause

over 70 % losses to crops each season in mid and high hills.

Common crops in bold are those that are raised through nurseries and harbour severe damage

due to pre-and post emergence damping off and root rot complex in the nursery itself causing

severe losses to the farmers due to high seed costs.

Strategies that can mitigate losses (of over 70%) due to seed and soil borne causative can

enhance production by the same proportion

Box 4


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maintaining and increasing biological diversity in the soil.

1. Soil solarization:

The use of clear polythene film to cover moistened soil and trap lethal amounts of heat

from solar radiation, termed as soil solarization. The pesticidial activity of soil solarization has

been found to stem from a combination of physical, chemical and biological effects. For most

vegetables, nursery is raised from the seeds and transplanted in the field. In the nursery, the seed

and the emerging seedlings encounter a plethora of soil pathogens and insects. As a result,

substantial portion of the nursery is lost due to seed rot, damping off, root rot, collar rot, stem rot

and insect damage. The left over seedlings are usually infected and poor in growth, and carry

infection to the field. Soil solarization is a low-cost technique to reduce losses due to insect pests

and diseases. Under the technique, nursery beds are prepared 5-8 weeks in advance of seed

sowing and are irrigated. Subsequently, they are covered with a transparent polythene sheet (50-

100 μ thick) in such a manner that there is no leakage of air from any point in the nursery.

Polythene sheet is removed 3-4 days ahead of the seed sowing time. The polythene sheet gives a

green-house effect whereby sun rays are trapped underneath. As a result, temperature of the soil

increases to a level that it becomes injurious to the soil microorganisms. Besides, it reduces weed

population, improved physical and chemical properties of the soil and increases population of

useful (friendly) micro flora in the soil. Since, plant pathogens are weakened through the effect of

solarization; they are over powered by the bioagents. In order to get maximum benefit from soil

solarization, it is necessary to perform the practice for about 5-8 weeks during hottest months of

the year using a transparent polythene sheet. Nursery beds must be irrigated before being

covered by polythene sheet and organic compost must be incorporated.

2. Preparation and use of vermicompost: Traditionally farmers use undecomposed farm yard

manure, which is deficient in nutrients and does more harm than good to the crop. Undecomposed

FYM promotes diseases, insects and pests and weed populations in the soil. On the other hand,

vermicompost is more nutritious and gets ready in lesser time. For its preparation, dung, crop

residue, green manure and other wastes are used by the earthworms to convert these to nutritious

compost. Vermicompost is balanced natural compost for vegetables, fruits and cereal crops. Use

of vermicompost reduces the cost of production, increases plant’s health and resistance against

biotic and abiotic causes and fertility and water holding capacity of the soil. Since the waste

material consumed by the earthworms passes through their guts, where it is acted upon by

enzymes and hence becomes nutritious for the crops. Of other species of earthworms, Eisenia

foetida has been found to be efficient in compost making.

3. Use of bioagents : Biological control is the sum total of harmful activities, which an organism

(biological control agent, abbreviated synonym “bioagent”) inflicts on the other. The term biological

control has been used in different fields of biology, more commonly in entomology and plant

pathology. In entomology, it has been used to describe the live predatory insects,

entomopathogenic nematodes, or microbial pathogens to suppress populations of different pest


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insects. In plant pathology, the term applies to the use of microbial antagonists to suppress

diseases as well as the use of host specific pathogens to control weed populations Continuous

use of pesticide results into the development of resistance in the pests, therefore use of bioagents

is a better alternative. More so because they are environment friendly and improve soil ecology

and health. During last two decades many bioagents have become commercially available in the

market of which Trichoderma and Pseudomonas spp. are quite popular for management of plant

diseases. Bioagents (microbial antagonists) could be used as seed treatment , rhizome

treatment , seedling treatment, compost treatment , spray or drench.

Use of bioagents offers several advantages: (i) it reduces cost of cultivation, (ii) it is

ecofriendly and does not affect the health of humans and animals, (iii) through its use pathogens

do not develop resistance and (iv) use of biaogents promotes seed germination and plant growth.

4. Value addition of vermi compost/ biocompost : Vermicompost/ biocompost should be

supplemented with bioagents (@ 250 g/q). This increases the nutritive value of the compost as

well as provides opportunity to the bioagant to grow faster on the compost so that it can compete

well with plant pathogens in the soil. Further, it facilitates rapid spread of bioagent in the soil.

Bioagent colonized compost acts as both biofertlizer and biopesticide because of its nutritional

superiority. Bioagent application through colonized compost is least expensive and the best

delivery system for biocontrol agents. Colonized compost also serves as inoculum for fresh

compost.

Through adoption CMP losses through seed and soil borne diseases could be severely

minimized. The ultimate aim is to raise healthy plant, which can resist/ withstand attacks of biotic

and abiotic aganets. This is achieved through maintaining microbial diversity in the soil, creating

conditions suitable for their growth and development through providing habitats for their growth.

The CMP tends to fulfill these objectives. Through the adoption of CMP farmers can reduce cost

of production, minimize losses due to pests and diseases, increase benefit-cost ratio and raise

value added crop. CMP has been extended¥ to over 3500 farmers from over 95 villages in

Uttarakhand hills through 124 trainings (farmers’ field schools).

Field observations revealed marked differences between the farmers who were adopting

IPM practices and conventional practices. This was a yardstick, showing how far the ‘older’

farmers have come. Importantly, they are applying the results to the bulk of their crops.

Management was a crucial element in producing healthy crops. For instance, crops failed where

farmers were busy with off-farm work. By comparison, committed farmers in disease prone areas

were visiting their crops weekly – in some places daily despite heavy rains – checking for disease,

roguing plants, and applying suggested measures. Diligence was seen to be a crucial factor in

pest and disease control. Seed quality and vagaries of weather were crucial to the

implementation of technology.

Experience of farmers adopting CMP nevertheless revealed that intensive vegetable

cultivation without complete reliance on pesticides and synthetic fertilizers is perfectly possible.


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The low-cost technology while on one hand offers a solution to recurrent disease and pest

problems, on the other falls with in the frame work of organic farming, which is the state policy.

CMP has a sound basis. The enthusiasm amongst people suggested that it would have wide

acceptability.

Although there is still a long way to go for local vegetable farmers to implement IPM

perfectly, the programme has contributed a lot to local vegetable production and to the upward

changes of farmers’ idea, habits and practice in pest management activities. However, certain

guidelines, such as the following, may lead the future course of action in sustaining vegetable

cultivation in the region through adoption of IPM: i). Initiating the establishment of a regional

network for the development and application of IPM in vegetables, ii). Establishing a databank on

IPM practices of vegetable cultivation and to make the information widely available, iii).

Strengthening the capacity for extension and training in IPM in vegetables and to develop

strategies to support IPM activities at various levels of the agricultural society, iv). Extending and

multiplying the pilot-stage training of lead farmers in vegetable IPM down to village/farmer level as

widely as possible, v). Strengthening and encouraging adaptive research for the development of

farmers' adoptable IPM packages, vi). Promoting supply of certified seeds of high yielding and

pest tolerant/resistant vegetable cultivars, vii). Minimizing pesticide use and promote safe and

judicious use of chemical pest control methods, viii). Developing a monitoring and surveillance

program for major pests of vegetables, ix). Ensuring sustained supply of quality bioagents and

biopescticides and x). Strengthening quality control units.

IPM techniques still are used by only a small number of farmers, primarily in pilot initiatives.

Government adoption of IPM as a part of its agriculture policy will move IPM from the level of

individual projects to increase the take-up, and bring benefits to the State. Farmers are largely

unaware of the benefits of adopting IPM practices but use cultural mechanical and crude botanical

pesticides, as well as indigenous and traditional knowledge for pest control. Encouraging farmers

to expand and adopt these pest management strategies, creating greater awareness of the

environmental benefits of IPM practices through education and training of extension agents and

farmers, and establishing mechanisms for recognition for farmers, who successfully adopt IPM

practices would not only facilitate the implementation of the IPM programme but also significantly

minimize the identified risks associated with pesticide dependent pest control strategies.

Certification of crops raised according to IPM or some other ecology-based standards may

give growers a marketing advantage as public concerns about health and environmental safety

increase. One goal of the program, in addition to being a marketing vehicle, would be to educate

consumers about agriculture and the food system. While the other goal would be to keep all

growers moving along the “IPM Continuum.”


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Metagenomics-A Tool for Identification and Characterization of Uncultivated Microbial Diversity

Ravindra Soni, Deep Chandra Suyal and Reeta Goel

Department of Microbiology, GBPUA&T, Pantnagar-263145 (Uttarakhand)

Microorganisms constitute two third of the Earth’s biological diversity. They can be

accessed primarily by a classical approach, involving culturing the microorganism by preparing a

solid or liquid growth medium containing appropriate carbon, energy and electron acceptor

sources depending on the physiological conditions under which the organism is to be isolated.

However, general routine conditions provided in the laboratory tend to impose selective pressure,

thereby preventing the growth of large number of microorganisms, but studies have shown that

only 1–15% of microbial genomes are cultivable under laboratory conditions and more than 85%

have never studied. Further, simple morphological and physiological traits of microbes can

provide few identification clues. This problem can be rectified by the use of phylogenetically

directed isolation strategies. Therefore,culture-independent methods are required to understand

the genetic diversity, population structure and ecological roles of the majority of microorganisms.

What is Metagenomics?

Microscope can visualized only culturable bacteria and still a large variety of microbes are

invisible. There are 1.9 x106 species of microorganisms (Hammond 1995) but less than 105

species of bacteria and fungi are documented (Bull 1992). In the case of bacteria a small fraction

form observable colonies on culture media and there is no clear cut evidence that cultivable

bacterial play a significant role in their environment because enrichment cultures are for those

adapted to grow in media and selective for fast growing microbes (Torsvik and Ovreas, 2002). As

Studies reveals that 99% are unculturable in laboratory conditions (Amann 1995) showing the

biasness of cultivation based technologies. Available literature support that(Kaeberlein 2002),

one of the important reasons for bacterial unculturability is the prerequisite for cellular signals from

organisms in coculture. Therefore, to unreveal the complete microbial community an approach

should be there which provide an easy way to explore those invisible magicians.

The concept of cloning DNA directly from environmental samples was proposed by

Norman R. Pace, in 1991 wherein, a phage vector was reported for such cloning. Modification by

Delong group in direct DNA cloning from seawater provided the landmark for this field (Stein et al,

1996). After these initiative steps several other groups used this idea for the exploration of

unculturable microbial flora. Therein, new modifications and methodologies have been developed

to find out the unseen prokaryotic diversity of different environments.


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Figure 1: Basic steps of Metagenomic library construction

Approaches & techniques of Metagenomics

Two different analyses have been used to obtain information from metagenomic

libraries: a function-driven approach, in which metagenomic libraries are initially screened for

an expressed trait, and a sequence-driven approach, in which libraries are initially screened

for particular DNA sequences (fig.2).

Realizing the potential for discovery from metagenomics is dependent

on the

advancement of methods that are central to library construction and analysis. For sequence-

based approaches, the speed and cost of nucleotide sequencing will be a barrier of rapidly

diminishing significance as sequencing technology continues to improve.

Moreover, sequence-

based assignment of function will also benefit from advances in detection of homology, which

will increasingly rely on the tertiary structures of predicted proteins rather than

simply on

primary sequences. Advances that will facilitate the management and analysis of large

libraries include bioinformatics tools to analyze vast sequence databases and reassemble

multiple genomes rapidly and affordable gene chips for library profiling

(Sebat 2003) or that

readily distinguish clones that are expressing genes from those clones that are silent. On the

other hand, Functional approach will require more innovation in method development. Most

important

among these are strategies to improve heterologous gene expression

and

approaches for efficient screening of large libraries.

http://mmbr.asm.org/cgi/content/full/68/4/669#R127


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Molecular

Tools used in

Metagenomics

Figure 2: Two different Metagenomic approaches: Sequenced based and function based.

Our On-going efforts

To explore the unculturable microbial diversity of Uttarakhand Himalayan region, efforts are

underway at different fronts: one is direct quantification of bacterial rRNA gene (Soni et al.

2010)to know the bacterial load on soil and the other is isolation of functional gene like bacterial

cold shock genes (csp) (Lata et al 2009) and nifH gene (Singh et al. 2010) etc. The metagenomic

Csp library was constructed from the temperate and glacier soils. Homology search of cloned

sequence revealed their identity with the Csp genes of Pseudomonas fluorescens,

Psychrobacter cryohalolentis K5 and Shewanella sp.MR-4. Further, analysis of amino

acid sequence of Csp recombinants revealed the sequence similarity with several cold stress

induced protein like rbfA, IF2, DEAD-boxhelicase, cold acclimation protein (EFTs) and temperature

induced proteins (SRP1/TIP1). This study highlights the prevalence of Csp gene(s) from cold

Himalayan environments which can be explored for tailored made crop as per the need of that

region in future.

Besides 16s rRNA gene library was constructed and sequenced from metagenome

isolated from six places i.e. Pantnagar (29.00 N, 243.8 mts), Chamoli (30. 51°N, 79.4°E,

1300mts), Ranichauri (78°30'E, 30°15'N, 1600 mts), Pithoragarh (80°2' E, 29° 47'N, 1967 mts),

Badrinath (30.440N, 790E, 3110mts) and Mana Glacier (30.440N, 790E, 3, 133m) of Uttarakhand.

More than 30 finally selected clones were sequenced and analyzed. Most of the clones are

showing homology with free living like Nostoc sp. symbiotic: Azorhizobium, Mesorhizobium


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nitrogen fixing and others related to nitrogen fixation process Nitrobacter sp., Nitrosococcus etc.

community like. It would be interesting to further screen them completely in view of their 100%

exploitations (Soni & Goel 2010).

REFERENCES

1. Amann, R.I., Ludwig, W., Schleifer, K.H., (1995). Phylogenetic identification and in situ detection of individual microbial cells without cultivation. Microbiol. Rev. 59, 143–169.

2. Bull A.T., Goodfellow M. and Slater J.H. (1992). Biodiversity as asource of innovation in biotechnology. Annu Rev Microbio. l46:219.

3. Hammond, P.M. (1995). Described and estimated species numbers:an objective assessment of current knowledge. In: Microbial 5 diversity and ecosystem function: proceedings of the IUBS/IUMS workshop, Egham, UK. University Press, Cambridge, UK, p 2.

4. Kaeberlein, T., Lewis, K. and Epstein, S.S., (2002). Isolating ‘Uncultivable’ microorganisms in pure culture by a simulated natural environment. Science, 296, 1127–1129.

5. Latha P. K., Soni R., Khan M., Marla S. S. Goel R. (2009) Exploration of Csp gene(s)from temperate and glacier soils of Indian Himalaya and in silico analysis of encoding proteins. Current Microbiology.58:343–348

6. Sebat, J.L. (2003). Metagenomic profiling: Microarray analysis of an environmental genomic library. Applied and Environmental Microbiology 69: 4927-34.

7. Singh C., Soni R., Jain S., Roy S. and Goel R. (2010)Study of nitrogen fixing bacterial community using nifH gene as a biomarker in different geographical soils of Western Indian Himalayas. Journal of Environmental Biology.31:553-556.

8. Soni R. Shaluja B.and Goel R. (2010) Bacterial community analysis using temporal gradient gel Electrophoresis of 16 S rDNA PCR products of soil metagenomes. Ekologija..56:3&4.

9. Soni R. and Goel R. (2010) Triphasic Approach for Assessment of Bacterial Population in Different Soil Systems. Ekologija.56:3&4.

10. Stein J.L.; Marsh T.L. wu K.Y., Shizuya H, Delong E.F. (1996). Characterisation of uncultivated prokaryotes :isolation and analysis of a 40 kilobase-pair genome fragment front a planktonic marine archaeon. J. Bacteriol. 178:591-599.

11. Torsvik, V. and Ovreas, L. (2002). Microbial diversity and function in soil: from genes to ecosystems. Curr. Opin. Microbiol. 5, 240-245.


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Effect of Climate Change on Plant-Pathogen Interactions

Rupam Kapoor Department of Botany, University of Delhi, Delhi

The science of climate change has matured considerably during the past decade, both

relative to the strength of the evidence documenting the ongoing anthropogenic climate change

and in terms of the quality of climate models projecting future changes in climate. The fourth

assessment report of the Intergovernmental Panel on Climate Change (2007) projects rising levels

of greenhouse gas and global temperature. The emerging body of knowledge strongly suggests

that climate change, especially changes in precipitation events, temperature and atmospheric

composition, will significantly add to the complex interactions in influencing plant diseases.

Pathogens drastically reduce plant growth in agricultural and natural ecosystems worldwide. The

makeup and functioning of natural ecosystems can also change dramatically because of

pathogens. Despite the paramount importance of plant disease to agricultural and natural

ecosystems, little is known of how disease will be affected by global climate change.Even the most

recent commentaries on food security advocating the priorities for climate change adaptation

needs continue to ignore impacts of pest and diseases on agricultural production and quality.

Process based models linking key elements of pathogen/disease cycle to crop models would be

more appropriate in projecting climate change impacts.

Given the integral role of environmental conditions in disease expression, altered

atmospheric composition is expected to modify plant disease expression and pathogen load

indirectly through changes in host plants (Chakraborty et al., 2008; Garrett et al.,

2006).Undoubtedly the nature of host (e.g. annual vs. perennial, C3 vs. C4) and pathogen (e.g.

root-infecting vs. shoot-infecting, biotroph vs. necrotroph) population and climate (e.g.asymmetric

temperature shifts will have different effects from changes in both maxima and minima) will

determine how the impacts of climate change will be felt. Consequently, climate change will

reduce, increase orhave no effect on a disease.

Structural, physiological, and chemical changes are common to many plants grown under

elevated CO2conditions and could also alter interactions with microbial pathogens (Coakley et al.,

1999; Karnosky et al., 2001). Many of these changes in host physiology can potentially enhance

host resistance. Significant increase in rates of net photosynthesis allows increased mobilization of

resources into host resistance at elevated CO2(Hibberd et al., 1996a). Other changes, including

production of papillae and accumulation of silicon at sites of appressorial penetration (Hibberd et

al., 1996a); greater accumulation of carbohydrates in leaves; more waxes, extra layers of

epidermal cells and increased fiber content (Owensby, 2006); lowered nutrient concentration,

leading to partitioning of nitrogen from photosynthetic proteins to metabolism that is limiting to

plant growth (Baxter et al., 1994); and greater number of mesophyll cells (Bowes, 1993) can all

influence host resistance.


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Reduced pathogen penetration results from a reduction in stomatal density (Chakraborty et

al., 1999) and stomatal conductance at high CO2(Hibberd et al., 1996b). Because many plant

pathogens infect leaves through the stomata (Agrios, 1997), any changes in stomatal structure

and function induced by elevated CO2may affect the infection process (Coakley et al., 1999). For

example, reductions in stomatal density (SD) and aperture could provide pathogens with fewer

and smaller points of entry, respectively. In addition, once infection occurs, changes in leaf

chemistry induced by elevated CO2 may alter the severity of infection.Whether changes in host

physiology would equally influence susceptible and resistant cultivars or resistance in both

traditionally bred and transgenic cultivars is not well known.

Though potential effects of climate change on crops have been investigated in detail,

knowledge about the impact on plant pathogens is still lacking (Runion, 2003). In fact, pathogens

could adapt to climate changes more rapidly than their hosts, because their multiple generations

give more opportunity for adaptation than the single generation per year of the crop plants

(Coakley, 1999). In particular, changes in temperature and rainfall patterns could directly affect

survival, development and reproduction of pathogens. With regard to temperature, warmer winter

conditions could favour pathogen overwintering (Manning & Tiedemann, 1995). The higher rate of

survival during winter could lead to an increase of the amount of initial inoculum and by contrast,

the dryer summer conditions of continental areas could reduce the incidence of those pathogens

that require free water on leaf or saturated soil for infection to occur (Coakleyet al., 1999).

The biggest threat to the durability of host resistance would come from accelerated

pathogen evolution. Changes will occur at all stages in the pathogen life cycle under elevated CO2.

Despite initial delays and reduction in host penetration, established colonies grow faster inside

host tissues at elevated CO2(Hibberd et al., 1996a).A combination of increased fecundity and a

favorable microclimate within enlarged canopies will provide more opportunities for infection.

There is evidence of adaptation for increased aggressiveness in some pathogens within three

sexualgenerations and controlled crossing has shown that aggressiveness is heritable and may be

polygenically controlled (Caten et al., 1984). For sexually reproducing pathogen populations with

broad genetic diversity,increased population size and the number of generationsin favorable

microclimates would increase the probability of more damaging pathotypes evolving more rapidly.

Warming will generally cause a pole-ward shift of the agroclimatic zones and crops that

grow in these zones. Pathogens will follow migrating host plants and their dispersal and survival

between seasons and changes in host physiology and ecology in the new environment would

largely determine how rapidly the pathogens establish in the new environment.More aggressive

strains of pathogens with broad host range, such as Rhizoctonia, Sclerotinia, Sclerotium, and

other necrotrophic pathogens may migrate from agricultural crops to natural plant communities.

Similarly, pathogens that are normally less aggressive in natural plant communities could

devastate crop monocultures growing in close proximity. Pathogens, in particular unspecialized

necrotrophs, may extend their host range to cause new disease problems in migrating


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crops.Expansion of host range may even occur in specialized biotrophs, as geographical proximity

is as important as phylogenetic relatedness in influencing the host range of some rusts (Savile and

Urban, 1982). As plants in both natural and agricultural communities can be symptomless carriers

of pathogens, any early predictions of impending damage will be difficult.

Most studies considering the effect of elevated CO2have been performed in greenhouses,

controlled environment chambers, transparent field enclosures or open top chambers. Data

derived from such work may not represent all aspects of natural systems (Long et al., 2004)

because of the exclusion of contributing abiotic and biotic factors. Open Top Chambers (OTCs)

have long been known to modify the environment by altering light intensity, relative humidity, wind

speed and direction, and other environmental factors. This is particularly disconcerting for studies

of disease occurrence when the chambers may interfere with the dispersal of natural inoculum or

alter the plant’s susceptibility to a given pathogen. If host plant resistance is to remain at the

frontline of the battle against devastating diseases like rusts, strategic experimental studies must

be made in environments that mimic future climate and atmospheric composition. Implementation

of Free Air gas Concentration Enrichment (FACE) systems has allowed researchers to expose

study plants to altered atmospheric composition in agricultural and natural ecosystems with

minimal impact on microclimate and without limiting the movement of biological organisms (e.g.

insects and pathogens). Realistic assessments of climate change impacts on host–pathogen

interactions are still scarce and there are only a handful of FACE studies. One of the most

important challenges for FACE research will be incorporating results of necessarily small-scale

experiments in larger scale predictions.

The global climate change will not only effect plant-pathogeninteractions, but also disease

management will be influenced due to altered efficacy of biological and chemical control

options.The shortage of such critical data on individual plant diseases needs to be addressed

using experimental approaches. Field-based research examining the influence of a combination of

interacting factors would be needed to provide a more realistic appraisal of impacts. Outcomes

from this research will have important implications for decisions on amelioration and management

strategies. Various gaps in knowledge and challenges related to study on impact of climate

change on plant-pathogen interactionswould be discussed.

REFERENCES

1. Agrios GN. 1997 Plant Pathology, 4th edn. San Diego, USA: Academic Press. 2. Baxter R, Ashenden TW, Sparks TH, Farrar JF. 1994 Effects of elevated CO2 on three montane

grass species. I. Growth and dry matter partitioning. Journal of Experimental Botany 45: 305-315.

3. Bowes G. 1993Facing the inevitable: plants and increasing atmospheric CO2. Annual Review of Plant Physiology and Plant Molecular Biology 44: 309-332.

4. Caten CE, Person C, Groth JV,Dhali SJ. 1984. The genetics of pathogenic aggressiveness in three dikaryons of Ustilagohordei. Canadian Journal of Botany.62: 1209-1219.

5. Chakraborty S. 2005 Potential impact of climate change on plant pathogen interactions. Australasian Plant Pathology 34:443- 448.

6. ChakrabortyS , Luck J , Hollaway G , Freeman A, Norton R, Garrett A, Percy K , Hopkins A, Davis


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C and Karnosky DF. 2008 CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources3,No. 054

7. Chakraborty S, Tiedemann AV, Teng PS. 2000 Climate change: potential impact on plant diseases. Environmental Pollution 108:317–26.

8. Coakley SM, Scherm H, Chakraborty S. 1999 Climate change and plant disease management.Annual. Review of Phytopathology37:399–426.

9. Coakley SM. 1999 Biospheric change: will it matter in plant pathology? Canadian Journal of Plant Pathology 17, 147- 151.

10. Coakley, SM, Scherm, H. 1996 Plant disease in a changing global environment. Aspects of Applied Biology 45: 227-237.

11. Garrett KA, Dendy SP, Frank EE, Rouse MN, Travers SE. 2006 Climate change effects on plant disease: genomes to ecosystems. Annual Review of Phytopathology44: 490–509.

12. Hibberd JM, Whitbread R, Farrar JF. 1996a Effect of elevated concentrations of CO2 on infection of barley by Erysiphegraminis. Physiological and Molecular Plant Pathology 48: 37 - 53.

13. Hibberd JM, Whitbread R, Farrar JF. 1996b Effect of 700 mmol per mol CO2 and infection of powdery mildew on the growth and partitioning of barley. New Phytologist 1348: 309-345.

14. IPCC. 2007. Climate change 2007: the physical science basis. Contribution of Working Group I to the 4th Assessment Report of the IPCC. UK: Cambridge University Press.

15. Karnosky DF, Gielen G, Ceulemans R, Schlesinger WH, Norby RJ, Oksanen E, et al. 2001 Face systems for studying the impacts of greenhouse gases on forest ecosystems. In: Karnosky DF, ScarasciaMugnozza G, CeulemansR,Innes J, (Eds.), The Impact of Carbon Dioxide and Other Greenhouse Gases on Forest Ecosystems. CABI Publishing: New York, NY, USApp.297-324.

16. Kimball BA. Adaptation of vegetation and management practices to a higher carbon dioxide world. In: Strain BR, Cure JD, (Eds.), Direct Effects of Increasing Carbon Dioxide on Vegetation, 1985. US Department of Energy, Washington, pp. 185-204.

17. Long SP, Ainsworth EA, Rogers A, Ort DR.2004 Rising atmospheric carbon dioxide: Plants FACE the future. Annual Review of Plant Biology 55:591-628.

18. Owensby CE. 2006 Climate change and grasslands: ecosystem-level responses to elevated carbon dioxide. In: Proceedings of XVII International Grassland Congress, 1119-1124.

19. Pangga IB, Chakraborty S, Yates D. 2004 Canopy size and induced resistance in Stylosanthesscabradetermine anthracnose severity at high CO2. Phytopathology94:221–27.

20. Runion GB, Curl EA, Rogers HH, Backman PA, Rodriguez-Kabana R, Helms BE.1994 Effects of free-air CO2 enrichment on microbial populations in the rhizosphere and phyllosphere of cotton. Agricultural and ForestMeteorology 117-130.

21. Savile DBO, Urban Z. 1984 Evolution and ecology of Pucciniagraminis.Preslia54: 97- 104.


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Soil Solarization and Its Application in Plant Disease Management

Y. Singh Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

There are several methods for the management of plant diseases which include fungicidal

application, breeding for disease resistance, sanitation, crop rotation, biological control and soil

disinfestations. However, usually none of them is perfect nor can any one be used under all

circumstances. Moreover, the life cycles of pathogens may vary in different crop systems, thus

requiring different management strategies. Therefore, any new method of disease management is

of value since it adds to our rather limited arsenal of control methods.

The concept of managing soil borne pathogens has now changed. In past, control of these

pathogens concentrated on eradication. Later it has been realized that effective control could be

achieved by interrupting the disease cycle, plant resistance or the microbial balance leading to

disease reduction below the economic injury level, rather than absolute control. The integrated

pest management concept encompasses many elements. In this context soil solarization can play

a significant role.

In Israel, extension workers and growers suggested that the intensive heating that occurs

in mulched soil might be used for disease control. By mulching the soil with transparent

polyethylene sheets in the hot season prior to planting, a team of Israeli workers developed a solar

heating approach for soil disinfestation (Katan, 1995). Soil solarization is a method of controlling

soil borne pests and pathogens by raising the temperature of the soil through application of

transparent polyethylene sheet to a moist soil surface. With solarization vast possibilities for

disease control are possible.

Terms used to describe the method- solar heating, soil solarization, plastic or polyethylene

tarping, polyethylene or plastic mulching of soil, solar pasteurization.

Principles

Heat is used as a lethal agent for pest control through the use of transparent polyethylene

soil mulches (tarps) for capturing solar energy.

Recommendations:

Transparent not black polyethylene should be used since it transmits most of the solar

radiation that heats the soil. Black polyethylene, though it is greatly heated by itself, is less

efficient in heating the soil than transparent sheet.

Soil mulching should be carried out during the period of high temperatures and intense

solar irradiation.

Soil should be kept wet during mulching to increase thermal sensitivity of resting structures

and improve heat conduction.

The thinnest possible polyethylene tarp (25-30 µm) is recommended, since it is both

cheaper and more effective in heating, due to better radiation transmittance, than the


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thicker one. Polyethylene reduces heat convection and water evaporation from the soil to

the atmosphere. As a result of the formation of water droplets on the inner surface of the

polythene film, its transmissivity to long wave radiation is highly reduced, resulting in better

heating due to an increase in its greenhouse effect. An ideal plastic mulch is that which is

100% transparent to solar radiation and completely opaque to long wave radiation. This

ideal mulch can increase soil temp. by 6-80c over ordinary polyethylene.

Since temperatures at the deeper soil layers are lower than at the upper ones, the

mulching period should be sufficiently extended, usually 4 weeks or longer, in order to

achieve pathogen control at all desired depths.

The solar heating method for disease control is similar, in principle, to that of artificial soil

heating by steam or other means. There are, however, important biological and technological

differences:

With soil solarization there is no need to transport the heat from its source to the field.

Solar heating is carried out at relatively low temps. as compared to artificial heating; thus

its effects on living and nonliving components are likely to be less drastic. Negative side

effects observed with soil steaming such as phytotoxicity due to release of manganese or

other toxic products and a rapid soil reinfestation due to the creation of a biological vacuum

have not been reported so far with solar heating.

Mechanism of disease control

Reduction in disease incidence in solarized soils results from the effects on host, pathogen,

and soil microbiota as well as the physical and chemical environment which, in turn affects the

activity and interrelationships of the organisms. Although these processes occur primarily during

solarization, they may continue after the removal of the polyethylene sheets and planting. The

most pronounced effect of soil mulching with polyethylene is a physical one, i.e. an increase in soil

temperatures, for several hours of the day. However, other accompanying processes such as

shifts in microbial populations, changes in chemical composition and physical structure of the soil,

high moisture levels maintained by the mulch, and changes in gas composition of the soil, should

also be considered while analyzing mechanisms of disease control. The following equation proposed

by Baker (1968), for relating the various factors involved in biological control, should be adopted for this

analysis:

Disease severity =inoculum potential x disease potential, where inoculum potential is the energy

available for colonization of a substrate (infection court) at the surface and disease potential is the ability

of the host to contract disease. More specifically the equation becomes:

Disease severity = (inoculum density x capacity) x (proneness x susceptibility), where capacity is

the effect of the environment on energy for colonization, and proneness is the effect of the environment

on the host. Of these four components, inoculum density (ID) is the one most affected by solarization

either through the direct physical effect of the heat or by microbial processes induced in the soil. The


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other components, however (except for susceptibility which is genetically determined) might also be

affected.

The Physical effect of heat: Whenever organisms are subjected to moist heat, at temps. exceeding the

max. for growth, their viability is reduced. The thermal death rate of a population of an organism depends

on both the temperature level and exposure time, which are inversely related. The response of a

population of a particular organism to elevated temp. depends on its physiological condition eg.

Propagule type, age, and on environmental factors. Moisture level is a crucial factor since

microorganisms are much more resistant to heat under dry conditions. The effect of water can be

explained by the dependence of heat stability of proteins on hydration. In the presence of water less

energy is required to unfold the peptide chain of proteins resulting in a decreased heat resistance.

Heating dry soil is therefore not effective in pathogen control. In arid zones, summer temperatures in the

upper layers of bare soils naturally reach similar to those recorded in solarized ones. Apparently this

heating is ineffective in disease control since the soil remains dry in summer in those areas. It is

worthwhile to examine the possibility that merely keeping the soil moist during the summer in those

regions may result in disease control. The most obvious and easily measured effect of high temp. on

pathogens is their mortality and the consequent reduction in ID calculated by estimating the number of

surviving organisms. The surviving individuals may, however, be also affected. They may be weakened

or partially damaged by heat. Weakened propagules may possess lower inoculum potential and shorter

longevity due to slower germination or growth, reduced number and length of mycelia germinating from a

multicellular propagule, reduced capacity to produce enzymes, ruptures in cell membranes and leakage

of nutrients from cells. Moreover, a weakened propagule may become more vulnerable to antagonistic

action in the soil.

Biological control: Microbial processes, induced in the soil by solarization, may contribute to disease

control, since the impact of any lethal agent in the soil extends beyond the target organisms. Induced by

solarization, biological control may affect the pathogen by increasing its vulnerability to soil

microorganisms or increasing the activity of soil microorganisms toward pathogen or plant, which will

finally lead to a reduction in disease incidence, pathogen survivability, or both. Thus both short and long

term effects might be expected. The mechanisms of biological control, which may be created or

stimulated by solarization are summarized as follows:

I. The effect on the inoculum existing in the soil.

A. Reduction in ID (in the dormant stage or during host penetration) through

1. microbial killing of the pathogen, already weakened by sublethal heat;

2. Partial or complete annulment of fungistasis and subsequent lysis of the

germinating propagule;

3. Parasitism or lysis by antagonists stimulated by solarization.

B. Reduced inoculum potential (IP) due to competition or antibiosis induced by

solarization.

C. Diminished competitive saprophytic ability of the pathogen, in the absence of the


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host, due to antibiosis or competition.

II. Preventing reinfestation through activities of microorganisms possessing mechanisms A2,

A3, B, and C

III. The effect on the host due to cross protection

Combining solarization with other methods such as pesticides or biocontrol agents

improves disease control. Whenever a pathogen is weakened by heating, even reduced dosages

might suffice for improved control combining with biocontrol agents, organic amendments, etc.

Volatiles and other mechanisms

Volatiles in the soil are involved in key processes, such as fungistasis and biological

control. Ammonia has been found involved in the suppression of Fusarium by oilseed

amendments. Permeability of polyethylene to many gases is very low. It is possible, therefore, that

certain volatiles, accumulated to high amounts and heated under the mulch, play a role in

pathogen control. If this is the case, then solar heating can be improved by adding suitable OM to

the mulched soil or by using mulch that is less permeable to volatiles.

Control of Weeds and other pests: Solarization results in an effective weed control lasting in

many cases for a whole yr. or even longer. The possible mechanism of weed control: direct killing

of weed seeds by heat; indirect microbial killing of seeds weakened by sublethal heating; killing of

seeds stimulated to germinate in the moistened mulched soil; killing of germinating seeds whose

dormancy is broken in the heated soil. Volatiles may also play a role in weed control.

Increased Growth Response: Different mechanisms, not related to pathogen control, have been

suggested for explaining IGR in disinfested soils: increased micro and macro elements in the soil

solution; elimination of minor pathogens or parasites; destruction of phytotoxic substances in the

soil; release of growth regulator like substances; and stimulation of mycorrhizae or other beneficial

microorganisms.

Advantages

Soil solarization as a disinfestations method, has potential advantages. It is a non chemical

method which is not hazardous to the user and does not involve substances toxic to the consumer, to

the host plant or to other organisms. In the right perspective it is less expensive than other methods.

This technology can easily be transmitted to the ordinary farmers and can be applied in large areas

manually and mechanically. Thus, it is suitable for both developed and developing countries. It may

have a long term effect, since effective disease control lasts for more than one season. This method

has the characteristics of an integrated control, since physical, chemical and biological mechanisms

are involved and because the control of varieties of pests is achieved.

Limitations

Solarization involves limitations, difficulties and potential negative side effects. It can only be

used in regions where the climate is suitable (hot) and the soil is free of crops for about one month or

more at a time of tarping with PE sheets.


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It is too expensive for some crops and ineffective in the control of certain diseases

Heat tolerant pathogens might develop after repeated application, though selection for

tolerance to lethal agents is not likely to develop with disinfestation methods which are not

target specific

Another possibility would be an increase in pathogen population due to a harmful effect on its

antagonists

Problem of degradation of plastic

Lines of Research

Cost Reduction: Possibilities for reducing the cost of mulching: (a) Used polyethylene (e.g. from

plastic tunnels) may be as effective as the new, thus reducing the cost to nearly zero (b) Reusing

the polyethylene, providing it is durable (c) If required during the growing season, durable sheets

may be used for both solarization and mulch (d) The production of thinner polythene sheets (of an

adequate strength) will reduce the amount needed per hectare.

Other Uses: Application of solarization for controlling root diseases of existing trees in orchards

should be examined.

Combining with other methods: Combining pesticides or biocontrol agents with solarization

improves disease control. Whenever a pathogen is weakened by heating, a synergistic effect is

expected; thus reduced dosages might suffice for improved control. Combining with biocontrol

agents might be especially effective in preventing reinfestation and in extending the effectiveness

of disease control.

Plastic Technology: 1) Biodegradable plastic 2) Polyethylene recycling processes should be

further developed 3)Developing economic, novel plastic or other materials more efficient than

polythene in trapping solar energy, thus reducing our dependence on climate and making this

available to cooler regions 4) Possibility of plastic material that can be sprayed on the soil, instead

of polyethylene mulching, should be explored.

Biodegradable Plastic (Manufacturers and Suppliers)

Jaipur Polymers, Jaipur

Symphony Polymers Pvt. Ltd., Pune

Om Bioplast Pvt. Ltd., Pune

Bio-D Plastics, Gurgaon

Seazell International, New Delhi

Bio Bags, India, Chennai

Sachdeva Plastics, New Delhi

Juneja Plastic Industries, New Delhi


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Precision Farming with Special Relevance to Irrigation and Fertigation

P. K. Singh Department of Irrigation & Drainage Engineering, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Introduction

Applications of agricultural inputs at uniform rates across the field without due regard to in-

field variations in soil fertility and crop conditions does not yield desirable results in terms of crop

yield. The management of in-field variability in soil moisture, fertility and crop conditions for

improving the crop production and minimizing the environmental impact is the crux of precision

farming. It's about doing the right thing, in the right place, in the right way, at the right time. It

requires the use of new technologies, such as global positioning (GPS), sensors, satellites or

aerial images, and information management tools (GIS) to assess and understand variations.

Precision farming may be used to improve a field or a farm management from several

perspectives. Better irrigation (Precision Irrigation) is one of the engineering perspectives of

precision farming.

We first need to establish common under standing to clarify or explain the term precision

irrigation. The traditional meaning of precision irrigation has been that of given in the literature, is

referred to as irrigation scheduling. That is scheduling based on environmental data, whether that

data comes from local field sensors or from more global sources such as regional meteorological

information at precise locations (within the soil profile) or at precise times. Perhaps good example

of this traditional definition of drip irrigation, which is generally accepted as a very precise irrigation

technique because water can be precisely controlled with regard to application rate, timing and

location with respect to the plant. This definition continued to be used today in many countries

except in USA and western world where more than 60% irrigated area is under sprinkler irrigation

(centre pivot system). However, in this paper we define precision irrigation as site specific irrigation

water management , specifically the application of water to a given site ( right place) in a given

volume (right amount) at right time (when) in a right manner (irrigation method) needed for

optimum crop production, profitability and other management objectives at the specific site. This is

in contrast with a simultaneous application of single amount of water to entire area of the irrigation

system / methods. During nineties in USA precision irrigation concept have been initiated at few

locations (Camp et al. 2006) mostly concerning to the hardware development and only a few

concerning to the site specific irrigation (Lu et al. 2004(a), Lu et al. 2004(b) and Lu et al. 2005).

This method of water management continues to be more or less a research issues. Development

of hardware is mostly in the area of variable rate applicators (sprinkler nozzles, control valves,

pumps, sensors etc.), and software to operate the system. However, exiting commercial self-

propelled system such as centre-pivot and lateral-move machines are particularly amenable to site

specific approaches because of their central level of automation and large area of coverage with a

single pipe lateral. This is reflected in some commercial irrigation systems that have recently been


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modified for precision irrigation. In addition to irrigation these machine offer an outstanding

platform for mounting sensors that can provide real time monitoring of plant and soil conditions

and serve as a transport device for nutrients and other agro-chemical application system. Adoption

of micro (drip / trickle) irrigation and fertigation systems are at an accelerated rate in the developed

and developing world for the wide spared horticultural and row crops. This system also offers a

site specific management of water and nutrients in precise manner with the application of

controllers and sensors. The development of efficient and cost effective hardware and software

shall be able to accelerate the adoption of a complete precision irrigation system by the all

category growers.

Advantages and Limitations

Applying precision irrigation practices offers significant potential for saving water, energy,

and money. Further, it has the potential to increases crop yield. There is an additional positive

environmental impact from precision irrigation in that farm runoff, a major source of water pollution,

can be reduced. The major limitation associated with precision irrigation are limited application of

self propelled centre-pivot sprinklers for small land holdings, high initial cost, operation and

maintenance need skilled work force.

Irrigation Application System

In conventional types of irrigation valves, emission devices, sprinkler nozzles, application

rates have been altered by manual operations. Similarly, the movement of lateral line, travel speed

were also controlled/ adjusted manually. In newer systems use of controller and software has

made these jobs automatically in dynamic mode as per the requirement of the crop and field i.e.

site specific.

Sprinkler Irrigation: Numerous innovative technologies have been developed to apply the

irrigation water in dynamic mode (variable rate) to meet anticipated whole-field management

needs in precision irrigation primarily with centre-pivot and lateral-move irrigation systems. In

general, the operation criteria for these systems include case of retrofit to existing commercial

irrigation system, good water application uniformity within and between management zone, robust

electronics, compatibility with existing irrigation system equipment, by-directional communication,

and flexible expansion for future development and functional requirement. In addition,

management of precision water application must include the interactions between individual

sprinkler wetted diameters, the start / stop movement of towers, and solenoid valve cycling. These

new precision water application technologies generally can be classified as either (1) a multiple of

discrete fixed-rate application devices operated in combination to provide a range of application

depths, (2) flow interruption to fixed-rate devices to provide a range of application depths that

depend upon pulse frequency, or (3) a variable aperture sprinkler with time proportional control.

Multiple sprinklers, pulsing sprinklers and variable-orifice sprinklers have been developed in

different part of the world for the precision application of water to the crops.

Micro Irrigation: In low pressure irrigation system (drip, micro sprinkler, micro jet etc.) constant


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and variable discharge emitters have been developed by manufacturers to provide variable flow

rate at the specific site in the field. In micro irrigation there may be single or multiple emitters at a

point, the operation of one or more than one emitters could be possible with the precision irrigation

system. The operation time of emitters / lateral is possible through automatic hydraulic valves

controlled by the micro processor/ controller.

System Control

Various form of control systems have been developed for the surface, sprinkler and micro

irrigation system for the control of the self propelled sprinklers, emitters on the basis of time,

volume and real time feed back. The control system generally consists of a micro processor /

controller, communication system (wire / wireless), control valve and sensors. For example,

Remote Irrigation Monitoring and Control System (RIMCS) have been developed for continuous

move irrigation systems that integrate localized wireless sensor networks for monitoring soil

moisture and weather and provide control for individual or groups of nozzles with wireless access

to the Internet to enable remote monitoring and control. The RIMCS uses a Single Board

Computer (SBC) using the Linux operating system to control solenoids connected to individual or

groups of nozzles based on prescribed application maps. The main control box houses the SBC

connected to a sensor network radio, a GPS unit, and an Ethernet radio creating a wireless

connection to a remote server. A C-software control program resides on the SBC to control the

on/off time for each nozzle group using a “time on” application map developed remotely. The SBC

also interfaces with the sensor network radio to record measurements from sensors on the

irrigation system and in the field that monitor performance and soil and crop conditions. The SBC

automatically populates a remote database on the server in real time and provides software

applications to monitor and control the irrigation system from the Internet. Another example of

irrigation control system is EIT irrigation control system is a data collection and SCADA based

control system which utilizes EIT data telemetry products as well as third party supplied soil

sensors for monitoring and scheduling irrigation activities. The system is designed for flexibility

and ease of use. The Human Machine Interface (HMI) provides easy to use functions for setting a

selecting irrigation modes and soil moisture set points. The system comprises of three main

components. These are the central PC, sensor for monitoring soil moisture and telemetry for data

collection, valve and pump control.

Sensors

Sensors are the most important component of a precision irrigation control system which

provide the desired information for the control of the sprinkler nozzels / emitters, control valve etc.

Field Environmental Sensors Soil moisture sensors are the most common type of environmental

sensor employed for determining a crop’s water requirements. However, sensors for ambient

temperature and humidity in the crop’s field are also common. As stated above, full weather

stations may even be included in local sensors. Sensors are strategically located at a number of

points within a crop’s field in a way that covers variations in soil type and climate. Pressure


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transducers may also be employed in the field for monitoring the water pressure of irrigation

zones. For crops that require continuous flood conditions, such as rice, water level sensors at

various points in the field may be used. They may be used as direct real-time feedback for

automatic controls (discussed below) and/or data collection and logging. Sensor Data Collection

Sensors may be queried manually or automatically by a data collection system. Automatic data

collection systems will query at regular intervals (generally every 5-15 minutes or so) and then log

the data into a database for subsequent reference. Also, automatic data collection systems

generally require a wireless communications network of very low power data collection nodes with

solar cells and rechargeable batteries. Any node within the network may have one to several

sensors attached. Some nodes may be used only as a communication relay within the wireless

network. In addition to the wireless nodes, the network may also include switching hubs, routers,

and gateways. Viewing of real-time data as well as data in the database archive may be limited to

a local network on the farm or may be accessible from the Internet.

Auxiliary System Components

Location and alignment

The control system for most site-specific application systems use some form of spatiality

indexed data to determine the appropriate application rate for specific sites. The basis for these

spatially indexed data is typically a widely accepted georeference system, such as latitude and

longitude. Consequently, it is necessary to know the precise location of all elements of the

application system at all times during operation if accurate site specific applications are expected.

Various approaches have been used, but the greatest challenge is cost. Although it is often

desirable to have multiple location sensors along the truss length of a moving irrigation system,

cost would be prohibitive. A general solution has been to use one or two sensors to locate one or

both ends of the moving system and to calculate the location intermediate points. Because moving

irrigation systems consist of multiple segments or spans, with each end of the span moving

independently but within confined limits, the truss is not always linear. This is not a significant

problem for small systems, but misalignment can be significant for large system. Fortunately, in

many cases, the shape of the truss is consistent, predictable, and describable for specific

operational conditions.

The determination of precise locations for lateral move system is similar to that of centre

pivot systems concept that is more difficult because both ends move. Laser alignment system is

also used for such system. Although the travel path is constrained by the guidance system, some

variation usually exists in repeatability. The issues of tissue misalignment are similar for lateral

move and centre-pivot systems. In general, more sensors are required for determining locations in

lateral move systems than in centre pivot systems. Most lateral move precision irrigation systems

have used one or more GPS sensor to determine location.

Management database and decision support

Any information to be used in the precision management application must be indexed by its


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geographical location and stored in an electronic format that can be readily accessed by a

computer or computer based controller. As such, it operates as special purpose GIS. This

management database houses the data with which the control system operates the irrigation

machines, records the actual application amounts for later use or documentation, and provides the

framework on which a decision support system can operate. Data that may be stored could include

user-entered soil characteristics, cultural operations, or application maps. It could also include

historical geo-referenced data such as yield maps, past application maps, or cultural histories.

Spatial arrays of sensors either mounted on the system or in the field could potentially feed

information directly into the management database.

Variable water supply

Most conventional moving irrigation systems are designed for and operate with a constant

water flow rate and pressure to the system in which all sprinklers operate most of the time. With

precision irrigation, in which variable flow rates are required for several management zones within

the total system, water must be applied to the system at constant pressure but at a variable flow

rate. The magnitude of the flow rate variance depends upon the system design and operation

characteristics, but in extreme cases it can vary from full design flow rate to almost zero.

Nutrient application methods

In all known applications, variable rate application of nutrients has been accomplished by

maintaining a constant concentration of the nutrient in the water supply and using the variable rate

application capabilities of the irrigation machine to vary the amount of water applied. This requires

knowledge of the water flow rate: either by direct measurement or by calculation using the design

(or individually measured) flow rates of the segments that are operating at a given time. With that

information the controller must signal the nutrient pump to inject the nutrient solution at a flow rate

that is proportional to the system water flow rate.

Because site specific applications of fertilizers are often applied in less water than normally applied

during a single irrigation application, water deficits may occur in some areas within the system,

especially for arid climates in which irrigation machines must operate most of time. Furthermore,

multiple site specific fertilizer application during the growing season could further exacerbate this

problem. Conversely, site specific fertilizer applications could cause excess water application in

some areas, causing surface accumulation or possible leaching of nutrients.

Precision Irrigation and Aerial Remote Sensing

To reduce the cost of making objective precision management decision, another approach

would be to spread out the cost of information from each point over the biggest area possible

(www.precirieg.net). Borrowing on ACMG’s experience in the treatment of nears infra-red imaging

from the air, ISA and especially IMIDA, specialized in the treatment of data from space, have set

up an experiment to test this principle on the ground. They have selected in an orchard some trees

with a variable irrigation management to express symptoms that the reflectance in the visible and

near infra-red would be capable of detect.


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Major work to finely and precisely measure the water status of citrus trees has been carried

out. A pressure vessel has been used for the base leaf potential and, in the middle of the day, the

gas exchange have been measured at the level of leaves to calculate the photosynthesis rate, the

transpiration rate and stomatal conductance of the capacitative probes tom establish the soil’s

water status. After have provoked progressive water stress over a period of 50 days, the

reflectance values and vegetation indices were compared with that precise information.

They concluded that the visible band alone is not enough to establish a reliable relationship

between the real state of stress and the image observed. In contrast, the infra red canal is rather

highly correlated with stomal conductance and the transpiration rate. This allows for seriously

entertaining the possibility of using the satellite or aerial sensing using localized and quite

expensive information collection to assess water status of vast zones.

Cost-Benefit

The cost-benefit issues are certainly not the same throughout the world. The issues vary

with size of enterprise, type and size of irrigation system, crops produced, prevailing crop prices

and subsidies and production costs. Therefore, these issues will be discussed for two broad

categories-automated irrigation on medium to large sized farm and manually controlled irrigation

on smaller farms.

Large farms: Because commercially produced precision water management systems and crop

production functions needed for optimization are not yet available, it is difficult to develop accurate

cost-benefit scenarios. A critical factor is that water, fertilizer and pesticide applications should all

be included in the precision management system. Depending on crop, savings can be substantial

for pesticides applications, especially if custom applications such as aerial applications can be

avoided. Some savings may accrue from less water, fertilizer and pesticide use from selective and

improved accuracy of pesticide applications and from better utilization of manpower. Also, future

environment regulations may greatly change the feasibility of precision irrigation systems because

they may be able to accomplish applications with less environmental impact.

Smaller farms: Although the popular concept is that precision agriculture technology is

appropriate only for large, mechanized farms, primarily because of equipment cost and location

positioning systems, it is probably not true. Certainly the scale and type of equipment and possibly,

the technology will not the same for the two cases. However the basic concept of precision

agriculture, that of optimizing the management of each crop unit for maximum profit (or other

objectives) applies equally to both production scales.

Conclusions

For the profitable adoption of site specific water, nutrient and agrochemical application

systems, crop response information is needed for optimum management of these systems.

Existing control systems are generally adequate for maintaining site specific application of water,

fertilizer and pesticides if the basis for management can be represented by a digital map or file of

spatially referenced data. Although certain combinations of cost and availability of water may


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justify precision application of water alone, precision water application system must usually

incorporate fertilizer and pesticide applications to be cost effective. Initially this technology will

probably be used predominantly on higher value crops, such as vegetables but will cascade to

other crops as the cost decreases.

REFERENCES

1. Lu Y C, Camp C R and Sadler E J. 2004a. Efficient allocation of irrigation water and nitrogen fertilizer in corn production. Journal of Sustainable Agriculture, 24(4):97-111.

2. Lu Y C, Camp C R and Sadler E J. 2004b. Optimal levels of irrigation in corn production in the southeast coastal plains. Journal of Sustainable Agriculture, 24(1):95-106.

3. Lu Y C, Sadler E J and Camp C R. 2005. Economic feasibility study of variable irrigation of corn production in southeast coastal plains. Journal of Sustainable Agriculture, 26(3):69-81.

4. Camp C R, Sadler E J and Evans R G. 2006. Precision water management: current realities, possibilities and trends In: Hand Book of Precision Agriculture, Haworth pp 153-185.

5. www.precirieg.net Precision irrigation to make the best use of water resources.21p


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Induced Systemic Resistance against White Rust of Mustard by Pre-or Coinoculation with an Incompatible Isolate

R.P. Awasthi

Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand))

White rust, caused by the biotrophic oomycete pathogen Albugo candida (Pers. ex Hook)

Kunze, is an important disease of Brassica juncea (L.) Czern & Coss and B. rapa L. The pathogen

can infect all aboveground parts of the plant, producing characteristic white blisters (sori). Severe

infection culminates in systemic “staghead” infection of the inflorescence (often in association with

Peronospora parasitica), which is the main cause of yield loss in susceptible cultivars (2, 3, 16).

A candida exhibits specialization on different cruciferous species and cultivars within

species (16). The North American population of the pathogen has been categorized into races that

cause the most of severe disease on their respective homologous hosts, although some also are

capable of infecting heterologous hosts (13, 17).

In some host-pathogen systems, prior inoculation with an incompatible isolate can protect

plants against subsequent infection by a compatible isolate. There has been much interest in this

type of induced resistance, because it suggests the possibility of “immunizing” crops against

disease (10,18). Little work has been done on the interactions among isolates of pathogens

differing in virulence on the interactions among isolates of pathogens differing in virulence on

Brasica hosts, although Mahuku et al., (12) recently demonstrated that highly and weakly virulent

isolates of Leptosphaeria maculans can coexist in lesions on B. napus and described how isolates

can interact during disease development. The aim of our study was to determine the interaction

between incompatible (IN) and compatible (CO) isolates of A. candida on B. juncea. We measured

isolated interaction in terms of symptom expression and did preliminary investigations of physical

(competition for infection sites among zoospores) and host-mediated (defense-related enzymes)

factors associated with the interaction.

Fungal isolates:

Two single-pustule isolates of A. candida, originally collected by N.I. Nashaat at Pantnagar

in northern India during January 1995 (MAFF import license PHF 1307C/1253/114), were used.

The incompatible (with B. juncea) isolate (IA01A) was collected from toria (B. rapa); the compatible

isolate (IA102A) was collected from mustard (B. juncea). The isolates were maintained separately

on seedlings of accessions of the hosts from which they were originally colleted: PT-303 (B. rapa)

and Kranti (B. juncea).

Plant material:

A B. juncea accession (PPBJ-1) was used as the host throughout the experiments.

Seedlings were raised from untreated seed, either in 8-cm-diameter plastic pots or in 5-cm2 card

board jiffy pots (Nursery Trades (Lee Valley) Ltd., Cheshunt, UK.). Seeds were sown = 1cm deep

in a soilless peat-based compost mix (Petersfield Products, Cosby, U.K.). Seedlings that emerged


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were thinned to seven per pot. Compost was kept moist by placing pots in propagator trays

(35.5×21×18cm), each containing a layer of water = 1 cm deep. All plant material was raised in

1×2.5×1.3-m controlled environment (CE) cabinets set at 18/150C day/night temperatures and 16-

h photoperiod, with a photosynthetic photon flux (measured at seedling height) ranging from 70 to

110µ mol quanta sec-1 m-2. Seedlings were first inoculated 6 to 7 days after sowing, when

cotyledons were fully expanded but true leaves were still developing (i.e., growth stage (GS) 1.0,

as described by Sylvester-Bradley (21). Inoculation of first and second true leaves usually was

done 10 (GS 1.1) or 12 (GS 1.2) days after sowing. After inoculation, seedlings were returned to

the incubation chamber under the same conditions, except for a transparent propagator lid that

was placed over them to provide the high humidity required for successful infection.

Preparation of zoosporangia suspensions, inoculation, and disease assessment:

Inoculum (zoosporangia suspensions) was prepared by shaking excised cotyledons

supporting abundant sporulations in sterile distilled water (SDW) in a glass vial. Extraneous matter

was removed from the resulting suspension by filtering through several layers of muslin. Before

inoculation, zoosporangial suspensions were adjusted to the required concentration with a

hemacytometer slide and appropriate dilution with SDW. In preliminary tests, zoosporangial

germination was high (>90%) and similar at each of the inoculum concentrations used in the

experiments. Inoculation was done within 15 min of preparing zoosporangial suspensions.

Prior to inoculation, seedlings were sprayed with SDW to remove compost debris from their

surface and left to dry for 30 min. Inoculum was applied either by pipetting inoculum droplets onto

cotyledons or by spraying seedlings to runoff with an atomizer. When droplets were used, a total of

10µl was applied surface of each half of a cotyledon. Droplets of this size were used, rather larger

ones, because they were never observed to run off the inoculated cotyledon. To test the local

interaction between the IN and CO isolates, the isolates were applied either together as mixed

inoculum or separately in succession as close as possible to the same site on the cotyledons. To

test systemic interactions, various combinations of isolates were applied to opposite cotyledons.

True leaves each received a total of 25µl of inoculum in similarly sized droplets pipetted onto their

adaxial surfaces. Inoculum was agitated during application. Unless otherwise specifed, inoculum

concentrations of 1×105 (IN isolate) and 5×104 (CO isolate) zoosporangia per ml were used. In

experiments that involved different treatments to opposite cotyledons, the position of each

treatment was marked with a marker pen.

Disease reaction was assessed 7 days after inoculation, using a 0 to 9 scale (modified

from Williams (26) for both cotyledons and true leaves: 0=no symptoms or signs of A. candida

infection; 1=pinpoint necrotic flecks at inoculation site, no sporulation; 4=6to10% of leaf area

covered with pustules; 5=11 to 20% leaf area covered with pustules; 6=21 to 30% leaf area

covered with pustules; 7=31 to 50% leaf area covered with pustules; 8=51 to 75% leaf area

covered with pustules; and 9=>75% leaf area covered with pustules. At least seven seedlings

were scored for each replication of a treatment combination.


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All experiments involved three replications of each treatment, and propagator trays

receiving different treatments were arranged randomly within CE cabinets. All experiments were

repeated at least once. Mean disease severity was calculated for ach tray, and the values were

used in analysis of variance. F tests were used to assess the significance of treatment main

effects and interactions. Treatment means were differentiated using Fisher’s least significant

difference test (LSD). All analyses were done using the Genstat statistical package (Lawes

Agricultural Trust, Hertfordshire, U.K.).

Local and systemic induction of resistance:

In a preliminary experiment, batches of seedlings were either spray-inoculated with the IN

isolate or sprayed with SDW; 4 h later all seedlings were spray-inoculated with the CO isolate. In a

second experiment, seedlings were droplet-inoculated on one cotyledon (treatment A) with SDW

or the IN isolate followed by CO isolate and then inoculated on the other cotyledon (treatment B)

with either the CO or IN isolate. The possibility of systemic protection of true leaves was

investigated in a third experiment: both cotyledons of a seedling were spray-inoculated with the IN

isolate or with SDW as a control before the emergence of true leaves; 5 days later newly emerged

true leaves were droplet-inoculated with the CO isolate.

Effect of IN inoculum concentration on CO infection:

The CO isolate was droplet-inoculated either alone or in mixed suspension with increasing

concentrations of the IN isolate (0, 5×103, 1×104, 5 × 104, 1×105 zoosporangia per ml) on one

cotyledon per seedling from different seedling batches; the opposite cotyledons of all seedlings

received the CO isolate alone (1 × 105 zoosporangia per ml). Mixed suspensions were prepared in

such a way that the inoculum concentration of the CO isolate remained constant.

Importance of timing and sequence in IN and CO inoculations:

Both cotyledons of each seedling in a batch received droplet-inoculations with both the IN

and CO isolates, but the inoculations, were different time intervals between the applications of

each isolate. Both IN followed by CO and CO followed by IN combinations were tested in four

experiments. (i) In-tervals of 4 h between initial application of the CO or IN isolate or H2O followed

by application of the CO or IN isolate or H2O compared with simultaneous application of the CO

and IN isolates. (ii) Cotyledons were first inoculated with H2O or the IN isolate and subsequently

inoculated with the CO isolates 0, 1, 3, 5, or 7 days later. In similar experiments, true leaves 1 and

2 were inoculated with the CO isolate 5 or 7 days and 7 days, respectively, after initial inoculation

of cotyledons with H2O or the IN isolate. Results for cotyledons and true leaves 1 and 2 were

analyzed separately. (iii) Cotyledon 1 was inoculated initially with H2O or the IN isolates, and both

cotyledons were inoculated with the CO isolate after 0, 1, or 3 days. (iv) Cotyledons were initially

inoculated with the CO isolate and then with the IN isolate after 0, 1, 3 or 5 days. Cotyledons of

control seedlings were inoculated a second time with H2O. In all cases, disease reaction was


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scored 7 days after last inoculation.

Microscope observation of zoospore distribution:

A sub sample of four cotyledons was collected 4 h after droplet-inoculation with the IN

isolate alone. Cotyledons were washed thoroughly three times in SDW in a glass vial and mounted

in a 0.1% aqueous solution of Calcofluor on microscope slides. The location of zoospores in

relation to stomata was investigated with a fluorescence microscope (Leitz, Wetzlar, Germany)

fitted with a 380 to 440 nm exciter filter and a 475-nm barrier filter (22). The extent of zoospore

lodging over stomata was estimated by counting the number of zoospores over, or away from, 100

stomata under the site of the inoculum droplet on each replicate cotyledon.

Phenylalanine ammonia lyase and total soluble peroxidase as says:

Sub samples of cotyledons were collected at the time of droplet inoculation with the IN or

CO isolate and 1, 3, and 5 days after inoculation. SDW treated cotyledons were sampled at the

same times for the control. For each treatment combination, a 2-g sample was homogenized in 20

ml of homogenization buffer (0.1 M potassium phosphate, 50 mM sodium metabisulphite, 1 mM

phenylmethyl-sulphonyl fluoride, and 250 mM sucrose, pH 7.0). The homogenate was mixed with

2.5g of polyvinylpoypyrrolidone (standard grade, Sigma Chemical Co., St. Louis) and 1.25g of

Amberlite XAD-4 (standard grade, Sigma) ion-exchange resin for 2 min, filtered through two layer

s of muslin cloth, and centrifuged at 100,000 × g at 40C for 30 min. A 1-ml aliquot of supernatant

was purified further and desalted by centrifugation through a 2-ml Sepharose G25 mini-column

(3000 rpm for 5 min at 40C). The G25 column removes excess salt simple organic acids that might

interfere with both the phenylalanine ammonia lyase (PAL) and total soluble peroxidase (POS)

assays. PAL and POX activities were assayed by procedures modified from those reported by

Strack and Mock (20). For PAL, 50µl of supernatant was mixed with 950 µl of substrate butter

(10mM L-phenylalanine in 100mM potassium borate, pH 8.8), and the formation of trans-cinnamic

acid was measured at 290nm after 2 h of incubation at 300C. PAL activity was expressed as

nanomoles trans-cinnamic acid per gram fresh weight per hour. For POX, 50µl of supernatant was

mixed with 950µl of substrate buffer (4.5 mM guaiacol [50µl], 2.2 mM hydrogen peroxide [25µl of

30% stock], and 200 mM potassium phosphate, pH 5.8). The formation of tetraguaiacol was

recorded spectrophotometrically at 300C for 2 min, and a rate was determined. POX activity was

expressed as nanomoles tetraguaiacol formed per gram fresh weight per hour. Six assays for both

PAL and POX were performed for each sample.

Local and systemic induction of resistance:

A preliminary experiment indicated that pretreatment by spraying with the IN isolate

protected seedlings from the CO isolate (disease reaction = 3.92 versus 7.06 for the control;

standard error of difference between means = 0.326; F significant at P = 0.0006). The relative

virulence of each isolate of B. juncea accession PPBJ-1 and the local and systemic induction of

resistance to the CO isolate by the IN isolate are shown in Figure 1. Within the time (6 to 7 days) it

took the CO isolate to produce abundant white pustules on the lower surfaces of cotyledons the IN


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isolate produced few systems. Occasionally, IN-inoculated cotyledons became slightly curled, but

they had a disease reaction of only 0 or 1. Coinoculation with the IN and CO isolates

simultaneously on one cotyledon decreased disease reaction on the cotyledon, as well as on the

opposite cotyledon inoculated with the CO isolate alone. However, systemic protection (on the

opposite cotyledon) was not as great as local protection. If the opposite cotyledon was inoculated

instead with the IN isolate after the first simultaneous IN and Co inoculation, there was no change

in disease reaction on the cotyledon. There was no evidence that coinoculation with the two

isolates encouraged infection by the IN isolate.

Inoculating cotyledons with the IN isolate also protected subsequently emerging true

leaves against the CO isolate (P<0.001). The first and second true leaves were protected to a

similar extent.

Effect of IN inoculum concentration on CO infection:

The degrees of both local and systemic protection of cotyledons against the CO isolate

increased as the concentration of the IN isolate used in mixed inoculation increased (P<0.001).

Local protection was greater than systemic protection (P<0.001; Fig. 3). The pattern of protection

differed between local and systemic (P<0.001). Systemic protection was greatest at = 5 × 10 4

zoosporangia per ml, whereas, local protection continued to increase upto the highest

concentration of IN isolate applied sporangia per ml.

Importance of timing and sequence of IN and CO inoculation:

The local protection given by inoculation with the IN isolate increased when there was a

delay of as little as 4h before challenge inoculation with the CO isolate. Disease severity was

reduced compared with cotyledons inoculated with the CO isolate after 4 h of inoculations with

H2O, whether inoculation with the IN isolate took place before or after inoculation with the CO

isolate (P>0.001). However, inoculation with the IN isolate 4 h before the CO isolate gave the

greatest protection; protection was weaker with simultaneous inoculation with the CO IN isolates

and weakest with inoculation with the IN isolate 4 h after inoculation with the CO isolate.

Ther was clear evidence of both local protection of cotyledons and systemic protection of

true leaves induced by initial inoculation of cotyledons with the IN isolate (P<0.001), but there

appeared to be a decline in the systemic protection of true leaves, relative to control, when the

interval was extended from 5 to 7 days. However, the difference in disease severity between the

control and IN inoculation decreased as the delay until inoculation with the CO isolate increased

(P=0.001).

There also was evidence of both local and systemic protection of cotyledons induced by

the IN inoculation (P<0.001), but systemic protection was lower (P<0.001). Disease severity in

general decreased as the delay until inoculation with the CO isolate increased, but there was no

evidence of any change in this pattern as the length of the delay increased (P>0.35 for all

interactions with delayed inoculation with the CO isolates).

In another experiment, disease severity was reduced by = 50% when cotyledons were


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simultaneously inoculated with the CO and IN isolates compared with those inoculated

simultaneously with the CO isolate and H2O, but the difference became minimal as the delay until

inoculation with the IN isolate increased to 5 days.

Zoospore distribution on inoculated cotyledon surfaces:

At the zoosporangia concentration used for the IN isolate (1×105 zoosporangia per ml),

almost all (>97%) stomata under the inoculum droplet were occupied by encysted zoospores.

PAL and POX activities in inoculated tissues:

PAL and POX activities declined in uninoculated cotyledons during the course of the

assays, but inoculated cotyledons showed net increases in the activities of both enzymes, and the

difference from the control increased with time after inoculation (P<0.001). The activities of both

enzymes were consistently higher in IN-than in CO-inoculated cotyledons; the rate of increase in

POX activity was similar for the two isolates, but the rate of increase in PAL activity was greater

with the IN isolate. Cotyledons and true leaves that had been coinoculated with IN and CO isolates

simultaneously were not assessed.

Attempted infection of cotyledons by an IN isolate of A. candida provided various degrees

of protection of B. juncea seedlings, both local and systemic, against an CO isolate. The degree of

protection depended on the zoosporangia concentration of IN isolate applied, sequence of

inoculations, and interval between inoculations with the IN and CO isolates. However, the CO

isolate only produced symptoms comparable with an IN reaction when a very high concentration of

inducing (IN) inoculum was used. The protective effect was also greatest locally and appeared to

decline in usues remote from the point of IN isolate inoculation.

This interaction probably was not due to direct antagonism between zoospores of the two

isolates. A more likely explanation is a combination of two effects: competition between the

isolates for infection sites and inhibition of the CO isolate by host resistance responses induced by

the IN isolate.

Competition for infection sites is likely to have contributed to local protection conferred by

the IN isolate, at least in treatments involving IN isolate inoculation before the CO isolate. A.

candida zoospores must lodge over a stoma to initiate infection, and they must do so in an

orientation that allows the emerging germ tube to grow directly into the stomatal chamber.

Zoospores of the two isolates used in our study germinate from zoosporangia, encyst, and send

germ tubes into stomatal chambers at a similar rate. More than one zoospore can lodge over a

stoma, but once the stoma is occupied, the presence of one zoospore appears to reduce the

likelihood that subsequent zoospores will lodge and penetrate successfully (U.S. Singh, K.J.

Doughty, N.I. Nashaat, G.Ross, and S.J. Kolte, unpublished data). When the IN and CO isolates

were inoculated together, the IN isolate is likely to have prevented a significant proportion of the

CO isolate zoospores from penetrating successfully, particularly when a high IN zoosporangia

concentration was applied. The fact that local protection was greater when the IN isolate

inoculaum preceded the CO isolate inoculum by as little as 4h and less when the IN isolate


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followed the CO isolate than when the two isolates were inoculated together is consistent with this

hypothesis. Four hours between successive inoculations with the IN and CO isolates is long

enough to allow zoospores of the IN isolate to deny the CO isolate a proportion of stomatal

infection sites by blocking them. Also, increasing the delay between inducting (IN) and challenge

(CO) inoculations did not greatly increase the extent of local protection, and there was no

significant “curative” effect when the IN isolate was applied more than 1 day after the Co isolate.

Systemic protection against the CO isolate conferred by the IN isolate was host-mediated.

Local protection conferred by In isolate probably also was host-mediated, at least in part. For

example, treatments that involved inoculating a cotyledon with the CO isolate and then the IN

isolate (precluding the possibility of denial of infection sites by the IN isolate) also decreased the

extent of local symptom development. However, local symptom development was much less when

the isolates were inoculated at the same time or when the IN isolates was inoculated first. It is

difficult to estimate the relative contributions of competition for infection sites and induced

resistance to the local interaction between the two isolates.

Induced (IN) responses were likely to be relatively rapid ones, coinciding perhaps with

inhibition of haustorial development in the mesophyll, which appears to be the first indication of an

IN interaction (11, 23). The IN isolate probably was recognized by the host relatively early, and its

attempt to infect may have led to the release of elictors that condition the expression of plant

resistance genes-the products of which may inhibit infection by the CO isolate. This is consistent

with the earlier an greater increase in PAL activity and the slightly greater increase in POX activity

after inoculation with the IN isolate than with the CO isolate. Visible symptoms of hypersensitive

reactions of fungal infection commonly occur between 3 and 5 days after inoculation. However,

there are clearly other defense-related events that occur much earlier in resistance and

hypersensitive plants, including insolubilization of cell wall proteins and induction of various

enzymes and crucifer in-dole phytozalexins (15, 19). Both PAL and POX are associated with

induced resistance in various species and have various functions, including control of key stages

in biosynthesis of lignin precursors (PAL), strengthening of cell walls against pathogen invasion

(PAL and POX), and biosynthesis of indolylglucosinolates and in-dole phytoalexins (POX) (4, 7,

25). Dahiya and Woods (5) reported that infection by A. candida induced production of fungitoxic

phytoalexins in rapeseed (species unspecified). It is possible that increased PAL and POX

activities may contribute to protection of B. juncea against the CO isolate conferred by the IN

isolate. However, Brassica species also are capable of other biochemical responses to infection

that are not measured here, including production of pathogenesis-related proteins and

glucosinolates (6, 8, 19). Further studies need to be completed before the precise biochemical

mechanism(s) of the IN isolate-induced resistance can be identified.

The greater local and systemic protection resulting from increased inducing (IN) inoculum

corresponds with other studies (14). However, when increasing inoculum concentrations of the IN

isolate were applied to one cotyledon, there appeared to be a limit to the extent of protection of


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opposite cotyledons inoculated with the CO isolate, such that the response (and presumably the

signaling mechanism that invokes it) were greatest at relatively low inducing zoosporangia

concentrations.

The pattern of interactions between the CO and IN isolates of A. candida on B. juncea

corresponded, to some extent, to those found between highly virulent (HV) and weakly virulent

(WV) isolates of LEptosphaeria maculans on B. napus (12). However, in contrast to A. candida,

the optimum interval between WV and HV L. maculans inoculations was 24h, and it was possible

to achieve a curative effect up to 48h after HV inoculation.

Out controlled-environment studies suggest there are likely interactions in the field among

pathotypes of A. candida expressing different host specificities. In similar work, Voorrips (24)

concluded that induction of host resistance was a better explanation for interactions between

Plasmodiophora brassicae isolates deferring in virulence on B. oleracea than competition for

infection sites. In the A. candida B. juncea system, both competition and induced resistance may

be involved, although the relative importance of each in nature is determined by the amount of a

virulent inoculum present. In western Canada, where both B. rapa and B. juncea are grown, there

is a predominance of isolates that infect only B. rapa (13), and these might be expected to

interfere with infection by isolates specific to B. juncea. The scale and significance of these

interactions in crops depends not only on the virulence composition of the local pathogen

population, but also on the relative timing and proximity of cultivation of respective hosts and on

the likelihood that A. candida races differing in virulence coexist at infection sites, as is the case of

the L. maculans-B. napus (12) and other (1) systems. In our study the optimum local protection

that occurred after preinoculation with the IN isolate alone approached a response comparable to

an IN interaction when a high zoosporangia concentration (2 × 105 ml-1-) was used. The importance

of the timing and sequence of IN and CO inoculations to the induction of resistance to A. candida

in B. juncea suggests that major effects in the field are less likely than for L. maculans, for which

induced resistance appears to be more flexible (12).

Based on the results presented in out paper, biological control of A. candida based on

intervention with IN isolates appears difficult to achieve. The use of antagonistic or resistance-

inducing bacterial inoculants for control may be a more promising approach (9). However, the A.

Candida-B. juncea interactions described here may provide a useful model for identifying the

systemic biochemical responses that determine incompatibility.

Induce system resistance against white rust was demonstrated in an investigation of the

interaction between two isolates of Albugo candida that were compatible (CO) and incompatible

(IN) on a Brassica juncea accession, the IN isolate induced both local and systemic protection of

cotyledons and true leaves against the CO isolate. The extent of the protection was proportional to

the zoosporangia concentration used in the inducing (IN) inoculation. Protection was greatest

locally on cotyledons and least on true leaves (the most remote tissue from the point of the

inducing inoculation). Protection occurred when the two isolates were inoculated together but was


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greater when the interval between the IN and CO isolate inoculations was longer. The IN isolates

induced only slight protection when it was inoculated after the CO isolate. No induced

susceptibility to the In isolate occurred with any treatment. There was some evidence of

competition between Co and IN zoospores for infection sites (stomata). The occurrence of

systemic protection and changes detected in phyenylalanine ammona lyase and total soluble

peroxidase activities in inoculated cotyledons, particularly after the inducing (IN) inoculation,

suggested that host-mediated factors also may be involved in the interaction between the two

isolates.

REFERENCES

1. Awasthi, R.P., Nashaat, N.I., Heran, A., Kolte, S.J., and Singh, U.S. 1997. The effect of Albugo candida on the resistance to Peronospora parasitica and vice versa in rapeseed-mustard. Page 49 in: Abstr. ISHS symp. Brassicas; 10

th Crucifer Genet. Workshop.

ENSAR-INRA, Rennes, France.

2. Bisht, I.S., Agrawal, R.C., and Singh, R. 1994. White rust (A. candida). Severity in mustard (B. juncea) and its effect on seed yield. Plant Var. & Seeds 7: 85-89.

3. Dhaiya, J.S., and Woods, D.L. 1987. Phytoalexin accumulation in rapeseed leaves challenged with white rust (A. candida). (Abstr.) Can. J. Plant. Pathol. 9: 276.

4. Dixelius, C. 1994. Presence of pathogenesis-related proteins 2, Q and S in stressed B. napus and B. nigra plantets. Physiol. Mol. Plant Pathol. 44:1-8.

5. Doughty, K.J., Porter, A.J.R., Morton, A.M. Kiddle, G., Bock, C.H., and Wallsgrove, R.M. 1991. Variation in the glucosinolates content of oilseed rape (B. napus L.) leaves. II. Response to infection by Alternaria brassicae (Brek). Sacc. Ann. Appl. Biol. 118: 469-477.

6. Goyal, B.K., Verma, P.R., and Reddy, M.S. 1995. Suppression of white rust of mustard by foliar and seed application of microbial inoculants. (Abstr.) Can. J. Palnt Pathol. 17: 357.

7. Liu, Q., Rimmer, S.R., and Scarth, R. 1989. Histopathology of compatibility and incompatibility between noilseed rape and A. candida. Plant Pathol. 38: 176-182.

8. Mahuku, G.S., Hall, R., and Goodwin, P.H. 1996. Co-infection and induction of systemic acquired resistance by weakly and highly virulent isolates of Leptosphaeria maculans in oilseed rape. Physiol. Mol. Plant Pathol. 49: 61-72.

9. Mathur, S., Wu, C.R. and Rimmer, S.R. 1995. Pathogenic variation among A. candida isolates from Western Canada. (Abstr.) Phytopathology 85: 1175.

10. Petrie, G.A. 1988. Races of A. candida (white rust and staghead) on cultivated Cruciferac in Saskatchewan. Can. J. Plant. Pathol. 10: 142-150.

11. Pidskalny, R.S., and Rimmer, S.R. 1985. Virulence of A. candida from turnip rape (B. campestris) and mustard (B. juncea) on various crucifers. Can. J. Plant Pathol. 7: 283-286.


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Multilines and Cultivar Mixtures for Plant Disease Management

P.K. Shrotria Department of Genetics and Plant Breeding, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Introduction

Cultivation of resistant varieties is considered as most effective and economical method of

disease management. Resistance breeding involves management of two biological entities viz.

host plant and pathogen. In view of dynamic nature of pathogen the resistance gene(s) fall

susceptible after few years and therefore the resistance breeding programme is a continuating

approach. Breeding for disease resistance involve several methods like selection, line breeding,

poly cross breeding, hybrid and synthetic variety development and hybridization followed by

pedigree/bulk pedigree or back cross breeding. However for management of disease up to the

level where it is not able to cause the economic loss is important aspect of resistance breeding.

Since the mode of inheritance of resistance in host may be race specific (vertical) and/or non race

specific (horizontal) therefore, depending on the mode of inheritance several methods have been

proposed for better utilization of resistance gene(s) for disease management.

Management of Disease

Management of vertical resistance genes

Important factors for management of VR genes

VR can only reduce the outside inoculum or exodemic

VR is achieved by manipulating the host population for maximum disadvantage to

pathogen population

For management of vertical resistance genes following approaches may be useful

Recycling and sequential release of resistance genes: Varieties are replaced frequently

with each increase in new races of pathogen such that release of one gene with resistance

and wait until it become ineffective and then release second gene and so on.

Pyramiding of resistance genes: Simultaneous introduction of diverse genes for resistance

into cultivars such that the variety offer more than one physiological barrier against pathogen

and also prevent stepwise development of races virulent to varieties possessing different but

single genes for resistance.

Regional deployment of resistance gene: Resistant varieties with different resistance genes

are developed and recommended for different geographical regions of the country where the

crop covers sizable area. This type of gene deployment is essentially a geographical multiline

eg. control of Puccinia recondita of Wheat.

Chromosome or genome substitution: If genes for resistance are not available in the

cultivated species, it is some times transferred from related species/genera through inter

specific/inter genetic recombination. Whole genome/whole chromosome/chromosome

segment of recurrent parent is substituted by genome of donor parent with resistance genes.


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e.g. transfer of resistance to Clubroot disease (Plasmodeophera brassicae) from B .

campestris to B napus

Multiline Cultivar

A multiline cultivar is a population of plants that is agronomically uniform but heterogeneous

for genes that condition resistance to a disease organism. The concept of multiline is based on two

philosophies for disease management (Marshall 1977)

Clean crop approach: In this approach all component lines of the mixture will be resistant to all

prevalent races of the pathogens to be controlled. The objective of this approach is to keep the

crop as free of disease as possible and at the same time reduce the threat of disease losses due

to shift of racial composition of pathogen population.

Dirty crop approach: It is on the concept that each line in the mixture carries a different single

gene for resistance however none of the line is resistant to all known races of pathogen.

Such multiline protects the crop in two ways (Frey et al 1973). First by stabilizing the race

structure of pathogen population, thus ensuring that simple races carrying single gene for virulence

dominate in the pathogen population, and second by stabilizing each component of multiline so

that it is attacked by only one race (dominant in pathogen population) while remaining line (except

for the line to which race has virulent gene) will act as spore traps thereby reducing the rate of

spread of disease. In this way multiline cultivars would have an effect similar to the polygenic non

race specific or synthesized horizontal resistance in delaying the intercrop buildup of the

pathogen.

How the two approaches differ

Component lines of multilines in dirty crop approach require to confer resistance to only

part of the pathogen population and this will extent the useful life of strong resistance

genes present in component lines which even with moderate level of resistance is able to

control disease. Because of moderate level of resistance of component lines breeder will

have greater choice for selection of other good characters like yield, maturity etc.

With less risk of breaking down the resistance, breeder would also free/less bothered from

difficult task of continuously searching and incorporating new sources of resistant.

Moreover in both the approaches, 6-15 phenotypically similar lines differing for

gene for resistance are required.

Mechanism of action of multilines

The mechanism by which the multiline cultivars buffer against diseases is the reduction of

initial inoculum (X0) and rate of increase (r)

A component line of the multiline being selectively resistant to specific race population of

pathogen, reduces. X0 but had no effect on r whereas all component lines being resistant to all

prevalent races of pathogen does not reduce X0 but reduce r. Therefore by reducing both r and X0

the multiline matures with less damage due to less initial inoculums and reduced rate of epiphytotic


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development.

Another mechanism of action of multiline to buffer against disease can be explained on the

basis of reduced X0 and r due to spore trap. A component line of multiline has high race specific

resistance therefore reduce initial inoculum (X0) but at the same time a component line will be

completely susceptible to certain other races. However when series of such resistant genes are

placed in the multiline the population of plants serve as the spore trap which keep under control

the potential parental spore of pathogen to contribute off spring for future cycle thus reducing rate

of infection.

Vertical and horizontal resistance concept of mechanism

Vander plank (1962) introduced these terms. A variety with vertical resistance is resistant

to certain/few races of pathogen while with that of horizontal resistance the resistance is evenly

spread against all races of pathogen

Epidemy of VR and HR

Epidemiologically, VR act by decreasing the effect of oxogenous (incoming) inoculum but

doses not effect the rate increase of virulent races whereas due to HR the rate of increase in

reduced for all race

Effect of VR & HR separately and in combination on disease progress (Van der Plank

1968)

Concept of Multiline

The two programme viz. New York Programme (Jenson 1952) and Rockefeller Foundation

Programme (Borlang and Gibler 1953), introduced the concept of multilines. From the later

programme the first multiline viz. Miramer 63 of wheat having resistance to stripe rust and stem

rust, was released for commercial cultivation. From the Indian Programme, multiline viz. KSML-1,

KSML-3, KSML-4 of Kalyan Sona and PVML-1, PVML-2, PVML-4 of PV-18 having better

resistance to leaf rust as compare to their parents were developed .

Crop heterogeneity for disease management and Cultivars Mixture

Dependence on monoculture has continued to spread rapidly despites serious setback as

well as evidences that alternate methods are also feasible. In traditional agriculture, cultivation of

mixtures within and between plant species help protect crops against stresses. Report of rice

mixture containing two to five component lines matching for maturity and quality but otherwise

heterogeneous has been available. Even in the recent and modern agriculture system mixtures


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are being cultivated commonly e.g. Barley-Oat mixture, Wheat-Barley, Wheat-Gram etc.

The earliest record of value of crop heterogeneity for disease control is from eighteen

century (Groenewegen & Zadokas, 1979) where reduction in rust infection in mixtures of Wheat

and Oat has been reported. In the recent time the concept of multiline approach (Jensen, 1952) is

the example of scope of crop heterogeneity for disease control. The common theme is to have

crop heterogeneous for disease resistance character to be achieved by multilines or variety

mixtures.

Potential of mixture for disease restriction

To under stand this we have to analyze the fundamental difference in ability of mixture to

cope with abiotic and disease stress. While abiotic stress occur as single event e.g. frost, drought

etc. Neither of which are influenced either by pure variety or mixture. The mixture can survive

better through compensation between each other but will not never effect the abiotic stress. On

the other hand for biotic stress like disease/ pest, pure variety or mixture can influence

disease/insect progress directly by controlling the degree of stress. Therefore, potential of gains

from using mixture are greater for disease control/insect control (biotic stress) as compare to

protection against drought/frost etc. (abiotic stress).

Mechanism of disease restriction by mixtures

Mixture may restrict the disease spread relatively more to the mean of their components

provided that component differ in the degree of susceptibility. With appropriate mixture of spring

barley, reduction of up to 80% in powdery mildew infection compared with mean disease level of

components grown as pure stand has been reported.

Effect on out side inoculums

Mixtures affect the inoculum that comes from out side the crop differently from that

generated within the crop by providing diversification of host resistance. The amount of infection

caused by an exogenous spore shower landing on a mixture equals the mean infection of the

component lines. On the product of initial infection, mixture has its effect on restricting the spread

of pathogen population. The mechanism operates in three principal ways (Trenbath 1984, Burdon

& Chilvers 1976 & 1982 and Burdon & Shattock, 1980)

Through decrease in the spatial density of susceptible plant thus limiting the amount of

susceptible tissue in a given area, reducing survival of spores and reducing possibility of

them reaching to neighboring susceptible plant. Spore density is declined due to reduction

in plant density and smaller effect of dispersal. e.g .Due to shallow dispersal gradient,

Powdery mildew (Erysiphe graminis spread is restricted by mixtures).

Through barrier effect provided by resistant plant that fill the space between susceptible

plants. To work this mechanism, susceptible plants should be as small possible to minimize

the number of spores available to blow in to the barrier.

Through the resistance induced by non pathogenic spores such that normally pathogenic


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spores that land is same area are prevented from infecting or are limited in their

productivity. The phenomenon is cumulative at least by reducing the amount of inoculum in

each pathogen generation and can account for a considerable proportion of the disease

restriction noted in the mixtures. It should also be systemic which should increase the

cumulative effect.

Working of mechanism in epidemic conditions

As result of initiation of epidemic by exogenous inoculum, the duration of disease spread in

the mixture changes in relation to that in pure stand. The stage of disease restriction may

depend on constitution of mixture, quality and amount of exogenous inoculum at the

beginning of epidemic and number of pathogen generation during active development of the

epidemic. Infection may increase upto disease carrying capacity of pure line as it does not

reach the same level in the mixtures. The host continues to grow until it is harvested.

The amount of disease restriction varies depending on the structure of the mixture and

quality and quantity of exogenous inoculum. Based on the monitoring of the air borne

inoculum and its movement, theoretically it is possible to construct mixtures to give high

level of disease restriction.

In case of soil borne pathogen where the spread of pathogen is by spores or mycelium or

by splash dispersal, the mixture will have little or no effect on disease. Moreover the plants

resistant to soil borne pathogen will provide compensation for damage to susceptible plants

in a mixture. The value of such compensation will be determined by the distribution of initial

inoculum in the soil such that if patchy, then even un infected susceptible plants in the pure

stand may compensate for damage plants (e.g. restriction of spared of Helmithosparium

victoriae in oats- Ayanru & Browning 1977).

Adaptation of Pathogen to Mixtures

The rate at which the pathogen adapts to the mixtures, if able to do so, depends on the

selection coefficient of the phenotype with different combinations of pathogenity genes and relative

distribution of pathogen propagules within or between plants of the mixtures. It will also depend on

the quality of matching pathogenity genes. Therefore, it is always desirable to use host resistance

gene either that can not be matched by the pathogen or those which can be matched only by

pathogenity genes that carry severe penalty for survival of the pathogen. Unit area of host

genotype need to be as small as possible to maximize the restriction of disease spread.

Durability of Mixture

The potential durability of mixtures depends not only on the quality of pathogenity gene in

pathogen population but also on the number needed to overcome host mixture. The potential

durability of mixture will be much improved by increasing the number of different components or

by increasing the complexity of resistant genes (oligogenic /polygenic).

The components of variety mixture possess many differences among genes of greater as


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well as lesser effect on resistance. Due to this complexity of gene, the evolutionary process in the

pathogen in relation to resistance gene, pathogenesis will therefore slowdown and chances of

emerging out super race to overcome the resistance of mixtures may be least. Further, the

evolution of new race of pathogen reached different limits of infection on different varieties.

Therefore, if a particular mixture were to be used continuously it is desirable to provide

diversification among mixture and minimize difference in resistance between component.

Yield advantage in variety mixture for disease resistances

Mixtures with genetic variation may be expected to yield more than component mean in

variable environments. The yield advantage is achieved through restriction of disease spread

(White 1982). The gain obtained is equal to what expected through single average fungicide

treatment. Some time yield advantage may not be obtained because the restriction of infection is

not sufficient to limit the damage or because other than disease, some other stress is also

predominant.

Number & type of mixture components

The number of component should be kept to minimum with reasonable restriction of

disease progress. Dynamic use of all permutation of a small number of components will provide

greater durability. Another constraint with number is in matching the components for harvest

maturity and yield. Small number makes it easy to harvest them at the same time. While the

component varieties with similar yield help to obtain mixture yields as high or higher than that of the

best component.

Besides resistance and yield, the components should have ability to produce better quality

when in mixture with other components or better than mean of component lines (e.g. Barley

mixture have comparable mating quality).

Management of Horizontal Resistance

HR is evenly spread against all races of pathogen

It is stability is due to its polygenic inheritance

It reduce the apparent infection rate

Reduces the area of lesion progress of disease curve, sporulation capacity,

infection efficiency

Increase latent period and incubation period

e.g. Slowing down of Wheat Powdery mildew of Wheat and slow rusting of Oat of

Wheat

Multigenic variety

The Concept has been given by Watson and Singh (1982). These are true breeding

varieties/lines possessing two or more diverse genes conferring resistance to a predominant race

or spectrum of predominant races of pathogen

Genetics basis


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If a variety has two genes at locus A and B, the probability of single mutation will be 10-6

however, probability of simultaneous mutation at both loci A and B will be 10-12 therefore the

multigenic variety will have longer life.

How to develop

Select two varieties having diverse gene for resistance to same or different pathogen

Combine both the genes in one variety provided that

o Two genes should be linked

o Have different level of resistance

o Have lower level of resistance individually as compared to combination

Multilines, Line Mixtures vs. Cultivar Mixture

In multiline the component lines differ only by identified resistance genes while the line

mixtures developed from lines selected from hybridization of common parent. However in case of

variety mixtures, components may differ for many characters including disease resistance

therefore varietal mixture provides greater potential for practical application (Wolf & Berect 1980).

With varietal mixture the choice is extended to all available varieties. Besides, there is also greater

potential of mixing with resistant to a range of diseases alongwith abiotic stress each with many

qualitative and quantitative differences. Due to greater flexibility, better performance and problem

in registering multilines under Plant Breeder Right (European Economic Community), intension is

now shifted from multiline to heterogeneous crop or cultivar mixture.

Other related strategies for disease management

Growing of range of varieties, randomly dispersed in each season

Pyramiding resistance genes

o Using particular set of resistance genes in pyramid form and none of the

component gene are released for cultivation in simpler combination or alone.

Integration of different strategies to maximize effectiveness of disease control

o Diversification of variety mixture

o Combining qualitative and quantitative resistance in component lines

o Integrating use of fungicide with variety mixtures

o Dynamic use of mixtures by changing their composition in space and time to delay

the buildup of new race of major pathogens

Cultivar Mixtures: SWOT Analysis

Strength

Control of endemic for air borne foliar disease of cereals

Reduction in yield loss

Least possibility of emergence of super race

Better guarantee of high yield as compare to best variety

Inexpensively and simple strategy of disease management which can be added to


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or integrated with other strategies

Help to improve the efficiency and reduce fungicide use

Mixed seed can be provided to the farmers

Weaknesses

Problem in gaining acceptance of concept

Not acceptable to industrial agriculture which is market oriented

Compatibility of cultivars to be mixed- in terms of maturity, height, quality etc.

Opportunities

Mixtures can be grown as the seed crops

Opportunities for change of component

Opportunity to combine a range of positive characters not achievable in single crop

genotype.

Reduced dependency on mono culture

REFERENCES

1. Ayanru, D.K. G., Browning, J.A. 1977. Effect of heterogeneous oat populations on the epithytotic development of Victoria blight. New Phytol. 79:613-23.

2. Borlaug NE, Gibler JW (1953) The use of flexible composite wheat varieties to control the constantly changing stem rust pathogen. Agron Abstr p 81.

3. Burdon, J.J., Chilvers, G.A. 1976. Controlled environment experiments on epidemics of barley mildew in different density host stands. Oecologia 26:61-72.

4. Burdon, J.J., Shattock, R.C. 1980. Disease in plant communities. Appl. Biol. 5:145-219.

5. Frey KJ, Browning JA, Simons MD (1973) Management of host resistance genes to control disease. Z Pflanzenkrankh Pflanzensch 80: 160-180.

6. Groenewegen, L.J.M., Zodoks, J.C. 1979. Exploiting within-field diversity as a defense against cereal diseases: A plea for ‘poly-genotype’ varieties. Indian J. Genet. Plant Breed. 39:81-94.

7. Gupta S.K. (2008) Plant Beeding: Theory and Techniques. AGROBIOS (INDIA) Jodhpur. Pp 314-349.

8. Jensen, N.F. 1952. Intra-varietal diversification in oat breeding. Agron. J. 44:30-34.

9. Marshall, D.R. 1977. The advantages and hazards of genetic homogeneity. Ann. NY Acad. Sci. 287:1-20.

10. Singh D.P. and Arti Singh (2005) Disease and Insect Resistance in Plants. Oxford & IBH Publishing Co. Pvt. Ltd. New Delhi . pp 233-272.

11. Trenbath, B.R. 1984. Gene introduction strategies for the control of crop diseases. In Pest and Pathogen Control: Strategic, Tactical and Policy Models, Ed: G.R. Conway, pp. 142-68. Chichester: Wiley. 488pp.

12. Van der Plank J.E. (1968) Disease Resistance in Plants. Academic Press, London New York, pp 206.

13. Watson, I.A. and Singh. D. (1982). The future of rust resistant wheat in Australia. J. Aust. Inst. Agric. Sci. 28:190-197.

14. White, E.M. 1982. The effects of mixing barley cultivars on incidence of powdery mildew (Erysiphe graminis) and on yield in Northern Ireland. Ann. Appl. Biol. 101:539-45.

15. Wolfe, M.S., Barrett, J.A. 1980. Can we lead the pathogen astray? Plant Dis. 64:148-55.


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SAS: An Introduction and its Applications

S. B. Singh & R. S. Rajput Deptt. of Mathematics, Statistics and Computer Science, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Introduction

Statistical analysis is an important tool to extract as much information as possible from the

given data. Statistical computing methods enable to answer quantitative biological questions from

research data and help to plan new experiments in a way that the amount of information generated

from each experiment is maximized. Widespread use of computers and specialized high and

statistical software package have helped and greatly improved the ability of researchers to analyze

and interpret voluminous data. Developments in computerized statistical analysis have enhanced

the ability of researchers to come up with better conclusions. The statistical computing support

would be useful in improving the quality of agricultural research and make it globally competitive

and acceptable by way of publications in international refereed journals. SAS is a software that

strengthen high end computing environment for the scientists and faculty members.

What Is SAS?

The Statistical Analysis System (SAS) is a Computer Software for performing statistical

analysis of data.

SAS is a set of solutions for enterprise-wide business users and provides a powerful fourth-

generation programming language for performing tasks such as these:

data entry, retrieval, and management

report writing and graphics

statistical and mathematical analysis

business planning, forecasting, and decision support

operations research and project management

quality improvement

applications development

NAIP Project: Strengthening of Statistical Computing

Availability of SAS Software to SAU/ICAR institutes

Training programme for SAS


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Working of SAS Program

Overview of Base SAS Software

The core of the SAS System is Base SAS software, which consists of the following:

DATA step a programming language that you use to manipulate and manage your

data.

SAS procedures software tools for data analysis and reporting.

SAS Libraries

A SAS library is a folder where your SAS files are stored. After a library is created, SAS

has access to the files in that library.

A SAS library is a logical location of SAS Data.

Some Procedures

PROC CONTENTS

The contents procedure displays the descriptor portion of a SAS Data set

PROC PRINT

The print procedure displays the data portion (browsing) of a SAS Dataset

PROC FREQ

The freq procedure one-way to n-way frequency table

PROC MEANS

The Means procedure produces summary reports that display descriptive statistics.

Means, STDDEV, MIN, MAX

Some Procedures

PROC UNIVARIATE

The Univariate procedure produces summary reports that display descriptive

statistics. Moments, Basic Statistics measures, Quintiles, Extreme Observation,

PROC TABULATE

Viewing records tabulate form

Raw data

Data other

format,-Excel,

SPSS, text,

Oracle RDBM

Set

SAS

format SAS Proc Results

SAS Data step


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PROC REG

Performing Regression analysis

PROC CORR

Performing correlation analysis

Some Procedures

PROC GLM

Analysis of Variance, one way ANOVA,ANOVA with RBD,2-Way ANOVA

PROC TTEST

T-Test

PROC IML

Performing matrix algebra

PROC LOGISTIC

Analysis of Logistics Regression

Some Solution Tools

Time Series Forecasting System

The Time Series Forecasting system forecasts future values of time series

variables by extrapolating trends and patterns in the past values of the series or by

extrapolating the effect of other variables on the series.

Enterprise Miner

Analysis of data using some data mining techniques:-Decision tree, Artificial Neural

Network, Association rule, Clustering etc.

Experiment 1 - Create SAS data library & export data from excel sheet to your SAS data

Library.

Step-1 Create an Excel Work sheet that contains your data.

Step-2 On the Base SAS, Select File-> New->Library->fill your Library Name, select Engine (in

present case select Excel) and give path of Excel worksheet.

Step-3 Click OK button, your library with your excel data is created.

Step-4 Check your Library & Data.

Experiment 2-Explore sample data

Step-1 Go to explorer Tab, Click Libraries icon, Display-all active libraries.

Step-2 Click Sashelp library, Display-Contains of Sashelp Library, find Heart Data table.

Step-3 Click Heart (data table) icon, Display-Contains of table Heart

Experiment 3-Working with Proc Contents

The CONTENTS procedure displays the descriptor portion of SAS data set. General form of the

CONTAINS procedure

Proc contents data=SAS-DATA-SET;

Run;

Example


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Proc contents data=Sashelp.heart;

Run;

Experiment 4- Working with Proc Print

The PRINT procedure displays the data portion (browsing) of a SAS dataset. General Form of the

PRINT procedure

Proc print data=SAS-DATA-SET;

Run;

Example

Proc print data=Sashelp.heart;

Run;

Proc print data=Sashelp.heart;

Var Height;

Run;

Experiment 5- Working with Proc Freq

The FREQ procedure produces one-way to n-way frequency tables. General Form of FREQ

procedure

Proc Freq Data=SAS-DATA-SET<NLEVELS>;

Tables variable(s);

Run;

Example

Proc Freq data=Sashelp.heart;

Tables Weight cholesterol;

Run;

Proc Freq data=Sashelp.heart nlevel;

Tables Weight cholesterol;

Run;

Experiment 6- Working with Proc Means

The MEANS procedure produces summary report that displays descriptive statistics. General

Form of MEANS procedure

Proc means data=SAS-DATA-SET<statistics>;

Var variable(s);

Run;

Example

Proc means data=Sashelp.heart;

Var cholesterol;

Run;

Proc means data=Sashelp.heart n mean median mode std var q1 q3 nmiss max min;

Var cholesterol;


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Run;

Experiment 7-Working with Proc Univariate

The UNIVARIATE procedure produces summary reports that display descriptive statistics. The

general form of univariate procedure

Proc univariate data=SAS-DATA-SET;

Var variable(s);

Run;

The UNIVARIATE procedure produces the following section of output

Moments, Basic Statistics measures, Test for locations, Quantiles, Extreme Observations, Missing

values

Example

Proc univariate data =Sashelp.heart;

Var cholesterol;

Run;

Experiment 8-Working with Proc Tabulate

The TABULATE procedure displays descriptive statistics in tabular format. General Form of

tabulate procedure

Proc tabulate data=SAS-DATA-SET;

Class Classification –variable(s);

Var analysis variable(s);

Table page-expression, row- expression, column-expression;

Run;

Example

proc tabulate data=Sashelp.heart;

class weight height smoking;

var cholesterol ;

table weight all ,height all ,smoking all;

run;

Experiment 9 –Working with ttest proc

The TTEST analyse difference between two population means. General Form of Proc TTest

Proc TTEST data=SAS-DATA-SET;

Class Variable;

Var Variable;

Run;

Example

proc ttest data=Sashelp.heart;

class sex;

var cholesterol ;


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run;

Experiment 10 Working with Corr Proc

The CORR procedure to produce correlation statistics and scatter plots. General Form of Corr

Procedure

Proc corr data=SAS-DATA-SET<option>;

Var Variable(s);

With Variables;

Run;

Example

Proc Corr data=Sashelp.heart;

Var cholesterol;

With weight;

Run;

Proc Corr data=Sashelp.heart;

Run;

PROC corr data=Sashelp.heart nosimple plots=matrix(nvar=all histogram);

VAR cholesterol systolic smoking height weight ;

RUN;

Experiment 11 Working with Proc GLM

The GLM procedure use to analyse differences between population means. General form of GLM

procedure

Proc GLM Data=SAS-DATA-SET;

Class Variable;

Model Dependents=Independents

Run;

Quit;

Example

One way ANOVA

proc glm data=sashelp.heart plots(only)=diagnostics(unpack);

class bp_status;

model cholesterol=bp_status;

run;

quit;

ANOVA with randomized Block Design

proc glm data=sashelp.heart plots(only)=diagnostics(unpack);

class bp_status weight_status;

model cholesterol=bp_status weight_status;

run;


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quit;

Two way ANOVA

proc glm data= Sashelp.heart plots(only)=diagnostics(unpack);

class bp_status smoking_status;

model cholesterol= bp_status bp_status*smoking_status;

run;

Experiment 12-Working with REG Proc

The REG procedure enables to fit regression model to data. General Form of the REG procedure

Proc REG data=SAS-DATA-SET<option>;

Model dependent(s)= Regressor(s);

Run;

Quit;

Example

proc reg data= Sashelp.heart ;

model cholesterol=weight height;

run;

quit;

Experiment 13: Working with SAS/IML (IML: Interactive Matrix Language)

General Form of IML procedure

Proc IML;

IML statements;

Quit;

Writing a Matrix & display elements

Proc iml;

X={2 5 6, 12 23 45, 5 6 4}; /* create 3X3 order matrix */

Print X; /* display matrix */

Print X[ ,2]; /* display 2nd column */

Print X[2, ]; /* display 2nd row */

Print X[1,1,}; /* display [1,1]th element */

Quit;

Basic Operations on Matrixes

Proc iml;

a={ 1 2 3,2 4 5, 6 7 8}; /* cerate 3X3 order matrix a */

b={ 1 3 2,4 5 6, 7 6 8}; /* cerate 3X3 order matrix b */

c= a**3; /* matrix exponentiation */

d= a##3; /* element wise exponentiation */

e= a+b; /* element wise addition */


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f= a-b; /* element wise subtraction */

g= a*b; /* matrix multiplication */

h= a/b; /* element wise division */

i= a#b; /* element wise multiplication */

j= inv(a); /* calculate matrix inverse */

k= det(a); /* calculate determinant value */

l= diag(a); /* diagonal matrix */

print c,d,e,f,g,h,I,j,k,l; /* display results */

Quit;


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Innovations in Agrochemical Formulation Technology for Safety and Efficacy

Shishir Tandon

Department of Chemistry (Division of Agricultural Chemicals), GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Formulations

A pesticide product consists of two parts: active and inert ingredients. Active ingredients

are chemicals which actually control the pest. Inert ingredients are primarily solvents and carriers

that help deliver the active ingredients to the target pest; they serve to enhance the utility of the

product. Inert ingredients may be liquids into which the active ingredient is dissolved, chemicals

that keep the product from separating or settling, and even compounds that help secure the

pesticide to its target after application.

The combination of an active ingredient with a compatible inert ingredient is referred to as a

formulation.

Types of Formulations

1. On the basis of Use

Depending upon the intended use of pesticides there are different types of formulations

2. On the basis of state

Solids Liquids Gases

Dust or powders, Granules,

Pellets, Tablets Particulates or

Baits, Dry flowables, Wettable

powders, Ear tag/ Vapour

strips, Seed treatment, WDGs

Suspensions Concentrate (Flowables),

Solutions, Emulsifiable concentrates,

Gels, Aerosol, Ultra low volume

concentrates, Microemulsions,

Suspoemulsions

Fumigants,

sold as

liquids or

solids


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Factors Responsible for different types of formulations

• Chemistry of the active ingredient

• Toxicology of active ingredient

• Effectivity of the product against the pest

• Effectivity of the product on the plant, animal or surface

• Effectivity of the product on the environment

• Method of application and equipment used

• Rate of application

Choosing a Formulation

A single pesticide is often sold in different formulations. Different formulations of the same

active ingredient often behave differently. For example, some types of formulation may mix in

water better, while others may increase the chance of crop injury. Choose the formulation that is

suitable for the job. Things to consider include:

1. Percent of active ingredient.

2. Ease in handling and mixing.

3. Personal safety risk.

4. Type of environment (agriculture, forest, urban, etc.).

5. Effectiveness against the pest.

6. Habits of the pest or pest biology.

7. The crop to be protected.

8. Surface to be protected

9. Type of application machinery.

10. Danger of drift or runoff.

11. Possible injury to crop.

12. Cost.

Individual Formulations

1. Aerosols (A): Aerosols (pressurized cans, "bug bombs") very low concentrate solutions i.e.

contains a small amount of pesticide, or a combination of pesticides in the same formulation that

are driven through a fine opening as a fine spray or mist by a chemically inactive gas under

pressure, when the nozzle of can is triggered. Usually they are small, and the percentage of active

ingredients is very low.

Advantages: Aerosols are very convenient in that they are always ready to use. They are also a

convenient way to buy small quantities of a pesticide. They are easily stored and the pesticides do

not lose their strength (potency, activity) while in the can during their normal period of use.

Disadvantages: Aerosols are only practical for use in small areas. There is not much active

ingredient in any one can. Because of this, it is an expensive way to buy pesticides. Unfortunately,

they are also attractive playthings for small children and, if left within reach, are a hazard. Aerosols

can be dangerous if punctured or overheated. They may explode and injure someone. Don't ever


- 268 -

try to burn aerosol cans.

2. Dusts (D): A prepared dust is a finely ground, dry mixture combining a low concentration of the

pesticide with an inert carrier such as fine powder or talc, clay, or volcanic ash or powdered nut

hulls, or other such materials. There is a wide range in size of the dust particles in any one

formulation. They are used dry; never mix them with water. The percentage of active ingredient is

usually quite low.

Advantages: Dusts are ready to use as purchased and require no mixing. They can be applied

with simple, lightweight equipment even in commercial use. Active ingredients that may harm a

crop if applied as an EC can be applied without harm as a dust.

Disadvantages: Because dust particles are finely ground, they may drift long distances from the

treated area and may contaminate off target areas. While drifting they are highly visible and may

cause public criticism. When used outside, they are easily dislodged from the treated surface by

wind and rain and soon become inactive. Never apply dust formulations on a windy day.

3. Poisonous Baits: Poisonous bait is a food or other attractive substance mixed with a active

ingredient or pesticide that will attract and be eaten by pests and eventually cause their death. The

percentage of active ingredient is low compared to EC’s and other formulations.

Advantages: Baits are useful for controlling pests such as flies, rats, etc., that range over a large

area. Often the whole area need not be covered, just those spots where the pests gather. Baits

may be carefully placed in homes, gardens, granaries, and other agricultural buildings so that they

do not contaminate food or feed, and can be removed after use. Usually only small amounts of

pesticide are used in comparison to the total area treated, so potential environmental pollution is

minimized.

Disadvantages: Within the home, baits are often attractive and dangerous to children or pets and

therefore must be used with care. Outside, they may kill domestic animals and wildlife as well as

the pest. Often the pest will prefer the protected crop or food rather than the bait, so the bait may

be ineffective. When larger pests are killed by baits, the bodies must be disposed of. If not, they

may cause an odor and/or sanitation problem. Unfortunately, other animals feeding on the

poisoned pests can also be poisoned.

4. Granules (G): Granular formulations are made by adding the active ingredient to coarse and

porous particles (granules) of inert material like fired clay particles or corn cobs or walnut shells.

Like dusts, pesticide granules are dry, ready-to-use, low concentrate mixtures of pesticide(s) and

inert carriers. The percentage of active ingredient is lower than in an EC but usually higher than

that of a dust formulation. However, unlike dusts, almost all of the particles in a granular

formulation are about the same size and are larger than those making up a dust. A fine granular

pesticide pours like ordinary salt or sugar.

Advantages: Granules are ready to use as purchased, with no further mixing necessary. Because

the particles are large, relatively heavy, and more or less the same size, granulars drift less than

most other formulations. There is little toxic dust to drift up to the operator's face and be inhaled by


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him. They are usually safer to apply than ECs or dusts. They can be applied with simple, often

multi -purpose equipment such as seeders or fertilizer spreaders. They also will work their way

through dense foliage to a target underneath.

Disadvantages: With a few exceptions, granulars are not suitable for treating foliage because

they will not stick to it.

5. Low concentrate liquids or oil solutions (S) or Ready-To-Use (RTU): These formulations

are premixed, ready to use. These preparations are usually solutions in highly refined oils that

contain low concentrations of the pesticide. They are generally used as purchased with no further

dilution.

Advantages: Low concentrate solutions are designed to be sprayed as purchased. Because of

this, no mixing is necessary and this lessens the chances for making mistakes. Household

formulations have no unpleasant odors and usually the liquid carrier evaporates quickly and does

not stain fabrics, furniture, etc.

Disadvantages: Low concentrate formulations are usually fairly expensive for the amount of

actual pesticide bought and the uses for such materials are few and specialized.

6. Emulsifiable Concentrates (EC or E): These preparations are usually solutions containing a

high concentration of the pesticide. The active ingredient is mixed with an oil base (often listed as

petroleum derivatives) and contain wetting agents, stickers, and other additives and forms an

emulsion which is diluted with water or oil for application

Advantages: These formulations contain a high concentration of pesticide, so the price per pound

of active ingredient is rather low. Only moderate agitation is required in the tank, so they are

especially suitable for low -pressure, low-volume weed sprayers, mist blowers, and small home

ground sprayers. They are not abrasive and do not settle out when the sprayer is not running.

There is little visible residue, which generally allows their use in populated areas. Because of the

high pesticide content, the applicator is not required to store, transport, or handle a large bulk of

chemical for a particular job.

Disadvantages: It is easy to under dose or overdose because of the high concentration of

pesticide, if directions for mixing are not carefully followed. Mixtures of emulsifiable concentrates

may be phytotoxic. Also, because of the high concentration and liquid form, which is usually easily

absorbed through the skin, there may be hazard to the applicator. The hazard of improperly stored

concentrates can also be high. Because of their solvents, most liquid concentrates cause rubber

hoses, gaskets, and pump parts to deteriorate rapidly unless they are made of neoprene rubber.

Some formulations cause pitting in car finishes. They can cause a minor surface bronzing of light

colored fruit. They should be protected from freezing temperatures which can break down the

emulsifier.

7. High Concentrate Liquids, Spray Concentrates, and Ultra Low Volume (ULV)

Concentrates: They may be thought of as special EC formulations. They usually contain a very

high concentration of the active ingredient, as much as eight or more pounds per gallon. Most are


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made to be mixed with water or oil. ULV concentrates are made to be used directly without

dilution; they contain little but the pesticide itself.

8. Flowable Liquids (F or L): Some pesticides can be manufactured only as solid materials, not

as liquids as the active ingredients does not dissolve well in water or oil. Often these pesticides are

formulated as flowables. Flowables are made from very finely ground solid materials, which are

suspended in a liquid along with suspending agents, adjuvants, and other ingredients. In this form,

they can be mixed with water to form a suspension in a spray tank and applied. Flowables are

similar to emulsifiable concentrates and are used in the same way.

Advantages: Flowables do not usually clog nozzles and require only moderate agitation. They are

as easy to handle

9. Wettable or Soluble Powders (WP or SP): Wettable powders and soluble powders are dry

preparations containing a relatively high concentration of pesticides. Wettable powder formulations

are made by combining the active ingredient with a fine powder. Wettable powders do not form a

true solution and when mixed with water they form suspensions. Soluble powders formulation is

made from an active ingredient in powder form that dissolve in water completely to form solutions.

The percentage of active ingredient is usually high in SPs compared to ECs and WPs. The amount

of pesticide in these powders varies from 15% to 95%.

Advantages: As is true with liquid concentrates, the pesticides in wettable powders are relatively

low in cost and easy to store, transport, and handle. They are safer to use on tender foliage and

usually do not absorb through the skin as rapidly as liquid concentrates. They are easily measured

and mixed when preparing spray suspensions. WPs are less likely than ECs to damage sensitive

plants. In Soluble powder once in solution is prepared, agitation is not needed

Disadvantages: Wettable powders may be hazardous to the applicator if he inhales their

concentrated dust while mixing. They require good agitation (usually mechanical) in the sprayer

tank and will settle quickly if the sprayer is turned off. They cause some pumps to wear out quickly.

Their residues are more subject to weathering than liquid concentrates, and being more visible

may soil cars, windows, and other finished surfaces. Wettable powder formulations are abrasive to

pumps and nozzles. Not many SP formulations are available.

10. Dry flowables or Water Dispersible Granules (WDG): It look like granules, but are used in the

same way as wettable powders. They contain very high concentrations of active ingredient.

Advantages: They have several advantages over WPs: they can be poured from their container

and measured by volume like a liquid; they are safer to handle because there is little dust in the air

when they are measured and mixed.

11. Pressure-liquefied gases and Fumigants: Fumigants are pesticides in the form of poisonous

gases that kill when absorbed or inhaled. They are often stored under pressure. These

formulations may be injected into the soil, released under tarps, or released into a grain storage

elevator. Some liquid formulations not stored under pressure turn to gases or vapors after they

have been applied to the soil or crop.


- 271 -

Advantages: A single fumigant may be toxic to many different forms and types of pests.

Therefore, a single treatment with one fumigant may kill insects, weed seeds, nematodes, and

fungi. Fumigants penetrate into cracks, crevices, burrows, partitions, soil, and other areas that are

not gastight and expose hidden pests to the killing action of the pesticide.

Disadvantages: The area to be fumigated almost always must be enclosed. Even in outdoor

treatments the area must be covered by a tarp or the fumigant incorporated into the soil, so that it

doesn't escape. Fumigants pose a serious safety risk because they are highly toxic and easily

inhaled. Proper techniques and all recommended protective gear must be used when applying

them. Most fumigants can also burn the skin.

12. Solutions and Water Soluble Concentrates (S): These are liquids in their original state and

are completely soluble in water or other organic solvents.

Advantages: Properly prepared solutions do not leave unsightly residues. They do not clog spray

equipment.

Disadvantage: some Solutions and water soluble concentrates can damage crops.

13. Encapsulated pesticides: They are a fairly new type of formulation. The active ingredient is

contained in an extremely small capsule. The capsules are suspended in a liquid. This formulation

is mixed with water and applied with conventional sprayers.

Advantages: It is relatively easy and safe to use.

Disadvantages: It can cause significant hazard for bees because the bees may take the capsules

back to the hive with pollen.

14. Invert Emulsions: It contain a water-soluble pesticide dispersed in an oil carrier. They require

a special kind of emulsifier that allows the pesticide to be mixed with a large volume of oil, usually

a fuel oil. When applied, invert emulsions form large droplets which do not drift easily. Invert

emulsions are most often used along rights-of-way where there is a problem of pesticide drift on

non-target plants.

Advantages: Does not drift easily

Disadvantages: Special kind of emulsifier and large volume of oil is required

Catalogue of Pesticide Formulations types and International Coding System

AB Grain Bait

AE Aerosol dispenser

AF Aqueous flowable

AI Active ingredient

AL Other liquids to be applied undiluted

AP Any other powder

AS Aqueous suspension

BB Block bait

BR Briquette


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CB Bait concentrate

CF Capsule Suspension for Seed Treatment

CG Encapsulated granule

CL Contact liquid or gel (insecticidal or rodenticidal)

CP or TP Contact powder/ Tracking powder

CS Capsule suspension

DC Dispersible concentrate

DL Driftless formulation

DP or D Dustable powder or Dispersible powder/ Dust

DS Powder for dry seed treatment

EC or E Emulsifiable concentrate

ED Electrochargeable liquid

EG Emulsifiable granule

EO Emulsion, water in oil

ES Emulsion for seed treatment (Emulsifiable solution)

EW Emulsion, oil in water

FD Smoke tin

FG Fine granule

FK Smoke candle

FL or F Flowable

FP Smoke cartridge

FR Smoke rodlet

FS Flowable concentrate for seed treatment

FT Smoke tablet

FU Smoke generator

FW Smoke pellet

GA Gas

GB Granular bait

GE Gas generating product

GF Gel for Seed Treatment

GG Macrogranule

GL Emulsifiable gel

GP Flo-dust

GR or G Granule

GS Grease

GW Water soluble gel

HN Hot fogging concentrate


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KK Combi-pack solid/liquid

KL Combi-pack liquid/liquid

KN Cold fogging concentrate

KP Combi-pack solid/solid

LA Lacquer

LO Live Organism

LS Solution for seed treatment

LV Liquid vaporiser

MC Mosquito coil

ME Micro-emulsion

MG Microgranule

MV Vaporising mat

OD Oil dispersion

OF Oil miscible flowable concentrate (Oil miscible suspension)

OL Oil miscible liquid

OP Oil dispersible powder

PA Paste

PB Plate bait

PC Gel or paste concentrate

PO Pour-on

PR Plant rodlet

PS or P Seed coated with a pesticide (Pelleted)

RB Bait (ready for use)

S Solution

SA Spot-on

SB Scrap bait

SC or FC Suspension concentrate (=flowable concentrate)

SD Suspension concentrate for direct application

SE Suspo-emulsion

SG Water soluble granules (Sand granules)

SL Soluble concentrate (Slurry)

SN Active Solution

SO Spreading oil

SP Water soluble powder (Soluble powder)

SS Water soluble powder for seed treatment

ST Water soluble tablet


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SU Ultra-low volume (ULV) suspension

TB Tablet

TC Technical material

TK Technical concentrate

UL or ULV Ultra-low volume (ULV) liquid concentrate

VP Vapour releasing product

WG or WDG or DF Water dispersible granules (Dry flowable)

WP or W Wettable powder (= Water dispersible powder)

WSB Water soluble bag

WSP Water soluble pack or packet

WS Water dispersible powder for slurry treatment

WT Water dispersible tablet

XX Others

ZC A mixed formulation of CS and SC

ZE A mixed heterogeneous formulation of CS and SE

ZW A mixed heterogeneous formulation CS and EW

Test Parameters

In order to ensure the right quality of the pesticide, besides testing for the active ingredient,

it is also necessary to test other parameters give in the list below :

Type of Materials /

Formulations

Test parameters

Technical grade

pesticides

Moisture content, melting point, setting point, isomeric ratio,

relative density, acidity / alkalinity

Water dispersible powder Sieving test, suspensibility, wettability, acidity / alkalinity

Dusting powder Sieving test for particle size, bulk density after compacting,

acidity / alkalinity

Granules Encapsulation i.e. Attrition test and water run-off test, sieving

test for granule size, sieving test for dust, moisture, acidity/

alkalinity.

Emulsifiable concentrates,

Soluble liquids

Emulsion stability, cold test, acidity/alkalinity, flash point.

Combination Formulations:

Sometimes various pesticides are combined. Some pesticides are registered for use in

combination with a liquid fertilizer. If pesticides may be combined safely and effectively, they are

called compatible. If not, they are called incompatible. Incompatibility can be physical or chemical.


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Physical incompatibility means that the chemicals cannot physically be mixed together. Solid

materials may become deposited at the bottom of the spray tank or the ingredients may become

separated into two or more layers following agitation. In some cases, separate parts may come

together or foaming or curdling may occur. If chemicals are physically incompatible, the mixture

may not be sprayable or the concentrations may vary.

Chemical incompatibility: Even if some chemicals can be mixed together physically, there may

be other kinds of incompatibility that may reduce effectiveness or cause injury to the plant.

Summary

Pesticides come in various formulations. Some are easier to use than others. Some are

more effective than others in certain situations. The most commonly used formulations are

emulsifiable concentrates and wettable powders, but there are many other types available. It is

important to know which type of formulation is the safest and most effective for the crop and pest

you wish to treat. Do not combine pesticides that are physically or chemically incompatible.


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Innovations in Agro-chemical Application Technology for Safety and Efficacy

T.P. Singh

Department of Farm Machinery and Power Engineering, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

India is an agriculture based country where more than 60% of its population still depends

upon agriculture for their daily need. The country’s economy depends on the agricultural sector to

a substantial extent. Mechanization in agriculture has enhanced production and productivity of

major food grains, vegetables and fruits though timeliness of operations, better management of

inputs, improved quality of work and reduction in post harvest loses. Insects and pests cause

considerable damage to crops. According to an estimate India loses nearly 30% of its potential

crop due to insects, weeds and rodent attacks. The timely and proper application of pesticide not

only saves the crop from complete damage but its effective application may enhance the

productivity by over 30 percent. Therefore the importance of plant protection equipments can not

be undermined in agricultural production system not only for the control of insects, pests but also

for the survival of mankind.

The Pesticides industry plays a crucial role in protecting crops against possible damage by

weeds, pests, insects and fungus, both before and after harvest. India’s pesticide industry is the

largest in Asia and twelfth largest in the world. Pesticides, also referred to as agrochemicals, are

chemical compounds used for crop protection. Two main types of products being produced by

pesticide industry namely are Technical Grade Pesticides (the basic concentrated chemical

compound) and Formulations from these technical grade pesticides (the usable form of

pesticides). Agricultural usage of pesticide in India commenced in 1949 with the application of

BHC for locust control. With timely application of chemicals, according to an estimate, the crop

yield may increase between 50 to 500 percent.

Farmers use a large quantity of pesticides than actually required. During impaction and

deposition, some of the spray solution roles-off the crop and get wasted. According to a research

only about 20% of the spray volume and 1 to 3% of chemical pesticide reach the target plant

(Bowen et al., 1952). This results into losses of pesticides requiring its repeated / frequent

application. Therefore, it becomes necessary to learn about the various types of pesticide

application equipment as well as the application technique for effective control of insects, pests,

weeds etc without wasting these chemicals and also saving man and environment from its

hazardous effect.

Types of Pesticides

i) Based on type of use

Pesticides are available in various forms that are used for very specific purposes. The uses of

pesticides are listed as under:

• Insecticides that are used against insects


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• Fungicides are used for preventing fungus

• Herbicides are used for removing weeds

• Rodenticides are useful against rodents

• Nemanticides are used for killing pests in the plant root

• Regulants are used for nourishing plants

• Acaricides are used for mites, spider and ticks

ii) Based on toxicity

a) Reduced-risk Pesticides

Since 1993, EPA (Environmental Protection Agency, US) has expedited the registration of

conventional pesticides with characteristics such as very low toxicity to humans and non-target

organisms including fish and birds, low risk of groundwater contamination or runoff, low potential

for pesticide resistance, demonstrated efficacy, and compatibility with IPM. Materials meeting

these criteria are referred to by EPA as “reduced-risk.”

b) Minimum-risk Pesticides

Minimum-risk pesticides are certain products that are exempted from EPA registration and

therefore have no EPA registration number. They contain only active ingredients and inert

ingredients

c) Bio-pesticides

Bio-pesticides or biological pesticides, as defined by EPA, are certain types of pesticides

derived from natural materials such as animals, plants, bacteria, and certain minerals. These

include microbial pesticides, plant-pesticides and biochemical pesticides comprised of naturally

occurring substances that control pests by nontoxic mechanisms.

Methods of Pesticide Application

The pesticide application requires knowledge of biology of pest in order to determine that at

what stage it will cause maximum destruction. This will help in applying the pesticide at correct

place, in correct amount and in a correct method. The various application methods used for

controlling different types of pests are explained as under:

1. Pre-sowing Soil/Foliage Treatment - In this method the pesticide (Herbicide/weedicide) is

applied before sowing.

2. Pre-emergence Soil/Foliage Treatment – In this case the pesticide (Herbicide/weedicide) is

applied just after sowing but before the germination of seed.

3. Post-emergence Soil/foliage Treatment - Pesticides (Herbicide/weedicide) is applied after

the seed has emerged and may be only a few centimeters tall.

4. Foliar Application - Pesticide is applied on the leaves of plant for control of pests.

5. Directed application- Pesticide is directed on the weeds in the vicinity of plant.

6. Band soil application - Application of pesticide to a band or strip of soil where the crop will

be grown.

7. Band application - Pesticide is applied on a continuous restricted area of crop only.


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8. Soil injection - Fumigants are applied under the soil.

9. Spot treatment - Pesticide application on a particular portion of the plant.

Spray Techniques

Spray techniques are generally classified on the basis of volume of spray material to be

applied on the plant. These are high volume, low volume, ultra low volume, foam spraying and

dusting.

i) High volume spraying

High volume spraying is generally preferred for complex pest and disease management

under wide range of conditions. This method is quite expensive and both time and labor intensive.

Usually the volume of spray material to be handled is more than 400 lit/ha for cereal crops and for

orchards it is over 1000 lit/ha. Hydraulic sprayers are used to handle this large amount of solution.

ii) Low volume spraying

In this technique the volume of spray material is between 5 to 400 liters/ha. It utilizes air

stream as pesticide carrier with small quantities of liquid thus saving the material and labor. In this

case same effect can be achieved with 25 percent less spray material when compared with high

volume spraying.

iii) Ultra Low volume spraying

Spray volume to be handled is less than 5 liters/ha in this technique. The chemical is

undiluted form or formulated in oil. Ultra volume spraying technique is usually utilized in arial

spraying by aircraft as well as in hand held battery operated spinning disc sprayers.

iv) Foam spraying

In foam spraying technique foaming agent (chemical additive) is added to the spray

solution and with the help of a special nozzle (air aspirating nozzle) the spray solution is converted

into foam. The foam helps the operator to see the volume of spray material and location being

applied. This system is quite economical.

v) Dusting

In this case the chemical is applied in dust form which is carried up to the target mainly by

air stream as a carrier. Air stream is created through a fan or turbine blower. Normally chemical

application in dust form is done when the weather is calm and plants surface is wet with dew or

rain.

vi) Wet dusting

Wet dusting is suitable for the crops in semi-arid or drought area. Chemical dust and water

is discharged simultaneously which gets mixed just before the target. Higher chemical deposition

is achieved due to better adhering property.

vii) Formulated capsules

• Insecticides formulated in the form of granules is placed precisely into the developing root

zone

• Pesticide is released slowly from the pellets. This does not harm to:


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– Operator

– Animals and

– Beneficial insects

Principles of spray atomization

These are of following types:

i) Pressure or hydraulic atomization – In this case, the liquid under pressure breaks due its

inherent instability as it comes out of the nozzle.

ii) Gas Atomization – Liquid chemical is introduced into high velocity air stream which helps in

breaking of droplets.

iii) Centrifugal atomization – Liquid under low pressure is fed on a high speed rotating disc

and centrifugal force causes split of liquid into fine droplets.

Spray Quality

The spray quality is defined in terms of droplet size i.e. fine, medium or coarse. With

conventional spraying system, a large portion of the spray is often lost by airborne drifts of droplets

known as Exodrifts. Small droplets of pesticides have higher chemical effectiveness than larger

droplets. Droplets in the 120 to 300 um range has been found most efficacious.

Coarse droplets are much heavier than fine droplets and are less likely to be affected by

drift. However if the crop canopy is heavy and has a high percentage of ground cover then

medium-fine droplets are required to achieve better penetration, retention and coverage. Flat fan

nozzles do not provide good coverage and therefore the operator increase the pressure beyond

the recommended range (2-4 bar) to produce a finer droplet. These fine droplets may drift and are

less effective in penetrating the canopy.

To improve crop coverage twinjet nozzle can be used in place of flat fan nozzle which

produce the same volume of spray through two separate openings. These openings are situated at

the front and rear of the nozzle and increase the potential to hit the target by producing a finer

spray quality at a lower pressure.

Plant Protection Equipment

Plant protection equipment falls into two major categories which are:

i) Spraying equipment

These equipments are used for the dispersal of insecticide in liquid form and are commonly

known as sprayers.

ii) Dusting equipment

These are used for the dispersal of insecticide in powder form and are commonly known as

dusters.

Types of Plant Protection Equipment

The various types of plant protection equipment that are available in market can be classified as:


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i) Based on form of energy used

a) Hydraulic energy sprayer

This type of sprayer includes Hand Sprayers, Telescopic Lance Sprayer, Stirrup Pump

Sprayers, knapsack Sprayers, Rocking Sprayer, Foot Sprayer, hand Compression Sprayer, Power

sprayers and Tractor PTO Operated Sprayers.

b) Gaseous energy sprayers

This includes Knapsack Sprayer cum Duster (mist Blower), Power Operated Sprayer,

Tractor PTO Shaft Operated Sprayers and ULV Sprayers

c) Centrifugal energy sprayers

This includes Spinning Disc Sprayer where the pesticide in liquid form is dropped on the a disc

spinning at very high speed. The liquid is then broken into smaller droplets (mist) because of the

action of centrifugal force.

ii) Based on volume of spray

a) High volume sprayer- Hydraulic energy sprayers

b) Low volume sprayers- Gaseous/Centrifugal energy sprayers

c) Ultra low volume sprayers - Gaseous/Centrifugal energy sprayers

iii) Based on power source

a) Manually operated

1) Portable (Equipment carried by one person) - Hydraulic/Gaseous/Centrifugal energy sprayers,

Shoulder/belly mounted dusters, granule applicator

2) Movable (Equipment carried on wheels or lifted by two or more persons) - Hydraulic/Gaseous

energy sprayers, power dusters

b) Power operated equipment

1) Portable - Hydraulic/Gaseous/Centrifugal energy sprayers, Dusters, Granule applicators

operated by Petrol engine /tractor PTO /electric motor and self propelled

2) Movable - Hydraulic/Gaseous/Centrifugal energy sprayers, Dusters, Granule applicators

operated by Petrol engine /tractor PTO /electric motor and self propelled

iv) Based on droplet size (VMD)

i) Less than 50 micron - Rotary atomizer, Thermal Fogger, Aerosol Generator

ii) 50-100 micron - Gaseous and Centrifugal energy sprayers (mist Blowers, ULV sprayers)

iii) 100-150 micron - Gaseous/Centrifugal energy sprayers (Rotary Atomizers), ULV Sprayers,

Spinning disc sprayers, Dusters

iv) 200-400 micron - Hydraulic energy sprayers

v) 400-800 microns - Hydraulic energy sprayers

vi) Greater than 800 micron - Hydraulic energy sprayers


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Table: Volume of spray application

Sl No.

Terminology Application rate, l/ha

Field crops Trees and bushes

1 2 3 4 5

High volume Medium volume Low volume Very low volume Ultra low volume

> 600 200-600 50-200 50 < 5

> 1000 500-1000 200-500 50-200 <50

(Shahare, PU and Dave, AK 2010)

Sprayer

Sprayer is a machine which applies chemicals in liquid form mainly in the form of droplets.

Uses of Sprayers

The sprayers can be used for the following purposes.

• Application of herbicides to remove weeds.

• Application of fungicides to minimize fungal diseases.

• Application of insecticides to control insect and pests.

• Application of micronutrients on the plants.

Functions of Sprayer

The main functions of a sprayer are:-

• To break the liquid into droplet of effective size.

• To distribute them uniformly over the plants.

• To regulate the amount of liquid to avoid excessive application.

Types of commercial sprayers

Based on the power source it can be classified as:

1. Manually operated

• Hand sprayer

• Stirrup type

• Knapsack sprayer

• Foot sprayer

• Rocking sprayer

2. Power operated

• Engine operated

• Tractor operated

• Aircraft

Hand sprayer

It is also known as hand atomizer or garden sprayer. It is a small, light weight (gross weight

approximately 1.5 kg) and compact unit. The working capacity may vary between 500-1000 ml. It

works at very low pressure in the range of 0.15 to 0.35 kg/cm2. It is generally used for small

spraying jobs in small nurseries, kitchen gardens, homes, offices etc


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Hand Compression Sprayer

It has a cylindrical container of 500 to 3500 ml for holding the chemical solution with a

handle, spray lance, nozzle, cut-off device and built in air pump. The commercial size of this

sprayer varies between 12 and 14 liter. The air pump develops pressure in the range of 0.15-0.35

kg/cm2. The weight of the sprayer is approximately 6-7 kg. This sprayer is most suitable for

chemical application in kitchen gardens, animal treatments, timber treatments, preservatives,

solvents, disinfectants, liquid fertilizers and application in cereal crops etc.

Stirrup Sprayer

It is designed to pump the spray fluid directly from an open container, usually a bucket. The

hydraulic pump is put inside the bucket and held properly with the help of a foot rest. It has either

single or double barrel. As the plunger is continuously operated, pressure is built in the pressure

chamber and the delivery hose. As soon as the required pressure is built up, the spraying can be

done. It is most ideal for public health jobs like anti-malarial spraying as well as small scale

agricultural use. The sprayer weighs about 4-5 kg and provides a minimum discharge rate of 550

ml/min. The average working pressure, for public health use, is 1.8-2.5 kg/cm2 and 7 – 10 kg/cm2

for agricultural use.

Foot Sprayer

The foot sprayer consists of plunger assembly, stand, suction hose, delivery hose and

extension rod with spray nozzle. It does not have any built in tank for chemical. The pump has a

pump barrel and a pressure chamber. The plunger moves up and down when operated by foot

pedal. A ball valve is provided in the plunger assembly to allow the fluid to cross the plunger and

getting pressurized in the pressure vessel. One end of the suction hose is fitted with strainer and

the other end has flexible coupling. Similarly one end of the delivery hose is fitted with cut-off valve

and the other end with flexible coupling. The gross weight of the sprayer is about 8 kg and

provides a minimum discharge of 1200 ml/min. The working pressure is about 17-21 kg/cm2 and

can spray up to a maximum height of 6 meter. The sprayer is ideally suitable for spraying in

plantations, field crops in hilly terrain, field crops, orchards, tea, coffee, rubber, coconut, apple and

also on tall trees.

Rocker Sprayer

The rocker sprayer has a pump assembly, fixed on a wooden platform with an operating

lever, a valve assembly with two ball valves, a pressure chamber, suction hose with strainer and

delivery hose with spray lance. It is operated with a hand lever. The forward angular movement of

lever is about 15 deg where as backward angular movement is about 30 deg. By operating the

hand lever pressure is built in pressure chamber. The gross weight of the sprayer is about 10 kg

and provides a discharge rate of 1200 ml/min at a working pressure of 17-21 kg/cm2. The

maximum pressure generated is about 36 kg/cm2. This high pressure makes this sprayer more

suitable for chemical application on tall field crops, orchards and tree up to 5 meter tall.


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Ultra low volume sprayer

The sprayer has a motor powered by 6 or 12 volt battery. A spinning disc is attached to the

motor, having grooves or teeth which rotate at a very high speed (4000-9000 rpm). The disc

receives the concentrated chemical from a plastic container having a capacity of about 1 liter.

Average droplet size varies between 35-100 micron. It produces uniform droplet size with a narrow

range. The spray volume reduces to 10 % compared to a knapsack sprayer. The amount of spray

volume required to be handled is between 1-10 lit/ha.

Power Knapsack Sprayers

It is capable of applying chemicals in liquid, powder and granule form economically and

effectively. It utilizes a light weight engine (2-stroke petrol driven air cooled, 1.2 hp, 5500 rpm, 12.5

kg) to produce air stream with the help of a blower having a capacity of about 6 m3/min. The spray

liquid is discharged into air stream through an adjustable nozzle. Additional dusting attachment is

provided to convert the sprayer into a duster. The commercial unit has a chemical tank capacity of

about 11.5 liters with a small fuel tank of 1.25 liter. The discharge volume is in the range of 0.3-1.5

lit/min. It can spray up to a height of approximately 10 meters. The field capacity for manually

operated sprayer is approximately 10 hrs/ha with a spray volume in the range

of 100 to 200 lit /ha. It is suitable for spraying and dusting on field crops, orchards, tea and coffee

plantation, glass houses and tall trees up to 10 meter. The effective swath width is 4-5 meter.

Electrodyn Sprayers

The operation of an electro-dynamic type of sprayer is based on the droplet emerging from

the delivery gun with an electric charge. As each droplet has the same charge, the droplets repel

each other causing them to form a reasonably wide spray. In these oil is used as a chemical

carrier. The total volume of liquid to be sprayed over a hectare is only a litre or less than this.

Electrostatic Sprayers

Electrostatics means that the droplets are electrically charged. Electrical charging causes

an attraction force between the spray drops and the plant. Because they are charged, the droplets

do not drift away or fall on the ground. By using air-assistance in

combination with electrostatics the amount of spray material

reaching the plant is significantly increased. Under leaf coverage

has been shown to be increased by more than 70 fold. The water

is used as chemical carrier in electrostatic sprayers. A stream of

air is used to transport the droplet in air-assisted electrostatic

spraying. The deposition efficiency is more than twice than that of

hydraulic sprayers and non-electrostatic types of air-assisted

sprayers.

Air Assisted Sprayers

These can give a number of advantages: -

i) Increased penetration in dense crops


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ii) Improved work rates through the use of lower spray volume rates (lit/ha)

iii) 50-90% reduction in drift

iv) Being able to control the deposition of spray on the target location.

Types of Air Assisted Sprayers

The main types are:

i) Sleeve Boom Sprayers - A hydraulically driven fan blows air into an air sleeve of flexible

material with specially designed air outlets.

ii) Twin Fluid Atomizers (Air Jet Sprayers) - Air is fed from a high volume/ low-pressure

compressor mounted on the sprayer while the liquid is fed from a conventional pump. A

unique swirl chamber within the nozzle mixes the air and spraymix and the spray emerges

in a flat fan pattern.

Tractor operated Mist Sprayers

It is also known as aero blast sprayers and is a viable alternative to hydraulic sprayer. It

helps in chemical application on targets far from the sprayer. It uses air stream to carry the spray

liquid onto the plant canopy. In order to generate sufficient air stream a blower is provided which

gets its drive from tractor PTO through suitable drive. Turbulence of the out coming air blast

causes thorough mixing of spray fluid and air. The spray laden air proceeds from the sprayer to

displace original air in the plant canopy. Air blast distributes the chemical uniformly in the swath

The major portion of swath is covered by main spout where as the supplementary nozzle covers

the area nearer to tractor. The effective working width is about 13 meter. The effective field

capacity of such sprayers range from 2-2.5 ha/h for cereal crops and 4-4.5 ha for orchards at an

average speed of operation of 1.8 to 2.2 km/h. Aero blast sprayers have been designed for

economic and effective application of chemicals in orchards, grape gardens, vegetables and

cotton crops.

Tractor operated Air Sleeve Boom Sprayer

The control of pest can be achieved effectively if pesticides are properly applied at the

correct rate, at right time and on the target by appropriate equipment. In field crops like cotton the

pest attacks on the lower side of the leaves and mostly at the time of boll formation. The sprays

with conventional sprayer do not enter at the bottom position of the plant canopy and on the upper

and lower side of the leaves. For this purpose tractor operated air sleeve boom sprayers have

been designed for chemical application in cotton crop. The principle of working of this sprayer is

totally based on the replacement of air within the canopy of plant with spray laden air. In this

sprayer, the spray boom having hydraulic nozzles is fitted along a flexible air sleeve having series

of holes to deliver air at high velocity (28 -32 m/s) from behind the nozzles. The major components

in air sleeve boom sprayer are blower, spray boom, air sleeve, spray pump and accessories. The

length of boom is about 8.1m with 18 nozzles spaced at 45 cm. The number of orifice is 44 with 4

m long sleeve on each side. The tank capacity is 450 litres. It produces droplet size of 270- 193


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micron at 28 m/s and 187-169 micron at 32m/s with droplet density as 24-11 and 26-11

numbers/sq cm respectively. The laboratory tests have shown that the recommended value of

droplet density and droplet size could be obtained at air velocity of 26 m/s, air sleeve angle 30°,

nozzle angle 35° and height of boom 70 cm. The air velocity and air sleeve angle was observed

more effective as compared to nozzle angle and height of boom. The field capacity of the sprayer

has been found 12 ha/h. The comparative performance of air sleeve boom sprayer with tractor

operated aero blast, boom sprayer and hand compression sprayer has been found very effective

for the control of aphids, jassids, whitefly and thrips in cotton crop. This sprayer is also useful for

wide row crops.

Table: Technical specification of a commercial Air Sleeve Boom Sprayer

Sl No.

Parameters Specification

1 Length of boom, mm 7200

2 Number of atomizers 18

3 Spacing between atomizers, mm 440

4 Blower speed, rpm 3800

5 Type of pump Piston type ( 3 Numbers)

6 Tank capacity, lit 400

7 Pump capacity, lit/min 36

8 Tank material HD Polyethylene

Table: Comparative performance of air assisted and air sleeve boom sprayer

Sl No.

Test Parameters Air assisted sprayer

Air sleeve boom sprayer

1 Speed of operation, km/h 2.50 2.5-3.0

2 Effective swath width, m 13 8.8

3 Field capacity, ha/h 1.15-1.16 1.70-2.0

4 Tank filling time, min 25-27 25-27

5 Fuel consumption, l/h 3-4 3-4

Air-carrier sprayers (aero-blast sprayers)

Air-carrier sprayers are used for spray application in orchards and vineyards where the

target is far away from the sprayer. The air as carrier serves for transport of the liquid droplets

from the sprayer to the target foliage, penetration of the foliar canopy and deposition of droplets. A

blower is used to create a stream of air which carries the droplets to the required distance/ height.

The blower must have the sufficient discharge to replace the volume of plant canopy during

stipulated period for one tree. It is used for application of same quantity of chemical in 1/10th

volume compared to a hydraulic sprayer

Arial spraying

Arial spraying is done mostly with the use of an aircraft using ULV technique. It produces

very fine droplets less than 70 micron. It is used for controlling insects, pests and diseases as well

as for large scale spraying. Arial spraying is more common in developed countries where large


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sizes of farms are available with almost negligible agricultural laborers.

Hand Rotary Duster

It consists of a blower complete with a gear box and a hopper. Blower is operated by

rotating the crank at about 35-40 rpm. The blower sucks the dust or powder from the hopper and

pushes it out forcefully to achieve efficient dispersal. The operator carries the duster by means of

one or two shoulder straps and holds the lance in his left hand cranking the handle with his right

hand. The air output is about 0.3 -0.85 m³/min. A feed control lever is provided by which the

operator slide it to control the aperture at the bottom of the hopper and thereby controls control the

amount of feed. The hopper capacity is generally 5-6 litre and the weight of the duster is about 4-6

kg. Hand rotary duster is useful for continuous application of pesticide on cereals, pulses,

groundnut, cotton, tobacco, potato and other vegetable crops.

Common types of Spray Nozzles

i) Hollow cone nozzle (Disc and core type)

It is used primarily where plant foliage penetration is essential and where drift is not a

major consideration. It produces fine droplets. The spray angle is adjustable between 30-120 deg.

It is mainly used for insecticide application with knapsack sprayer

ii) Solid cone nozzle

The solid cone nozzle has 3 cores. The centre core fills the hollow cone produce by two

side cores. It produces large droplets at low pressure. The spray angle is between 20-30 deg.

Solid cone nozzles are used mainly for high volume spraying of chemical.

iii) Flood Jet nozzles

Flood jet nozzle produces wide, flat spray with large droplet size. The liquid discharged

from orifice strikes a curved deflector providing spray angle is between 70-160 deg. It is used for

fertilizer and post-emergence herbicides

iv) Flat fan nozzles

It produces medium size droplets providing even coverage. The spray angle is narrow to

medium. It is used for all type of fertilizer and insecticide application. Largely used for herbicide

application

v) Adjustable nozzles

It is a nozzle which is capable of producing a solid cone, hollow cone and jet spray pattern.

It can also produce spray pattern with different spray angles.

vi) Double swivel nozzles

This has two swivel nozzles instead of one, capable of independent movement. It is used

for high volume spraying in two different directions at a time.

Sprayer Maintenance

Sprayer should be well maintained during the spraying season.

Sprayer should be checked well before the beginning of the season.


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It should be cleaned from inside and outside after each day's work.

all moving parts should be lubricated thoroughly and regularly

Worn out, broken and damaged parts should be replaced.

Parts that are likely to be needed should be kept in stock.

Sprayer should be cleaned thoroughly before it is kept in the store to avoid corrosion

from residual chemical

Filters and Nozzles should also be cleaned thoroughly.

The pump should be greased and operating / moving parts should be well oiled.

Safety Precautions

Before spraying

Identify the pest and ascertain the damage done

Use recommended pesticide with less toxicity only if it has exceeded the Economical

Injury Level.

Read instructions manual of the pesticide and equipment.

Check the spraying equipment and accessories which are to be used.

Ascertain that all components are clean, especially filling and suction strainer, sprayer

tank, cut off device and nozzle.

Replace worn out parts such as 'O' ring, seal, gasket, worn out nozzle tip, hose clamps

and valves.

Test the sprayer and ascertain whether it pumps the required output at rated pressure.

Check the nozzle spray pattern and discharge rate

Make sure that appropriate protective clothing is available and is used.

Ensure that soap, towel and plenty of water is available

During spraying

Take only sufficient pesticide for the day's application.

Make sure pesticides are mixed in the correct quantities

Liquid formulation should be poured carefully to avoid splashing.

Selecting proper direction of spraying to avoid drift

Hold nozzle and boom at a proper height to avoid drift.

Wear appropriate clothing.

Avoid contamination of the skin especially eyes and mouth.

Follow correct spray technique.

Operate sprayer at correct speed and correct pressure.

DO NOT transfer pesticides from original container and packing into another container.

Do not spray in high wind, high temperature and rain.

Never eat, drink or smoke when mixing or applying pesticides.

NEVER blow out clogged nozzles or hoses with your mouth.


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Never allow children to be nearby during mixing.

NEVER leave pesticides unattended in the field.

Never spray if the wind is blowing towards grazing livestock or pastures regularly used

or habitat.

After spraying

Remaining pesticides left in the tank after spraying should be emptied and disposed off in

pits dug on wasteland.

Never empty the tank into irrigation canals or ponds.

Never leave unused pesticides in sprayers. Always clean equipment properly. After use, oil

it and then keep away in store room.

Do not use empty pesticide containers for any purpose.

Crush and bury the containers preferably in a land filled dump.

Clean buckets, sticks, measuring jars, etc. used in preparing the spray solution.


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Wheat Rusts: New Virulences threatening Global Wheat Production and Strategies to Manage

K.P. Singh


Introduction

Stem or black rust of wheat, caused by fungus Puccinia graminis Pers. F. sp. tritici Eriks. &

E. Henn., was at one time the most feared disease of wheat worldwide. It was not until the

beginning of the 20th century and soon after the rediscovery of Mendel’s laws, that Biffen in 1905

demonstrated that inheritance of resistance to wheat yellow rust, caused by Puccinia striiformis,

followed Mendel’s laws. After two devastating stem rust epidemics in North America in 1904 and

1916, another important finding came from the work of Stakman and Piemeisel 1917 who showed

that stem rust pathogen had various forms or races. These races varied in their ability to infect

different wheat varieties which later were found to carry distinct resistance genes or combinations

thereof. Strong emphases to identify resistance to stem rust and breed resistant wheat cultivars

were given in the USA, Canada, Australia and Europe. A simultaneous effort was also made to

understand rust epidemiology and evolution, which led to the barberry eradication programme in

North America and Europe and formulation of genetic control strategies. Efforts to find a solution to

stem rust also initiated global collaboration among wheat scientists who grew and evaluated wheat

germplasm for resistance to stem rust.

Table 1. Originating genus and species and usefulness of designated Sr genes in conferring

seedling and/or adult plant resistance to Ug99 race of stem rust pathogen P. graminis f. sp. tritici

Origin of Sr genes Stem rust resistant (Sr) genes

Infective Effective

Triticum aestivum 5, 6, 7a, 7b, 8a, 8b, 9a, 9b, 9f, 10, 15, 16, 18, 19, 20, 23, 30, 41, 42, Wld-1

281, 292, Tmp

Triticum turgidum 9d, 9e, 9g, 11, 12, 17 22, 1312, 141

Triticum monococcum 21 22, 35

Triticum timopheevi 361, 37

Triticum speltoides 32, 39

Triticum tauschii 332, 45

Triticum comosum 34

Triticum ventricosum 38

Triticum araraticum 40

Thinopyrum elongatum 241, 25, 26, 43

Thinopyrum intermedium 44

Secale cereale 31 271, 1A, 1R

Almost 50 different stem resistance genes are now catalogued (5), several of which are

incorporated in wheat from alien relatives of wheat (Table 1). All but one of 50 resistance genes

are race-specific, and are expressed in both seedling and adult plants. Race specificity derives

from the gene-for-gene relationship between the host plant resistance gene and corresponding

virulence genes in the pathogen. Gene Sr2, transferred to wheat from ‘Yaroslav emmer’ by


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McFadden 1930, is the only catalogued gene that is not race-specific. Sr2 can confer slow rusting

resistance of adult-plant nature. Resistance gene Sr2, in addition to other unknown minor genes

derived from cultivar Hope and commonly known as ‘Sr2-Complex’, provided the foundation for

durable resistance to stem rust in germplasm from university of Minnesota in the USA, Sydney

University in Australia, and the spring wheat germplasm developed by Dr. N.E. Borlaug as part of

a programme sponsored by the Mexican Government and the Rockefeller Foundation.

The importance of stem rust declined worldwide with the deployment of various other alien

resistance genes such as Sr 24, Sr 26, Sr 31 and more recently Sr 38. Translocations carrying

these genes, except that with Sr 26, also carried additional genes that conferred resistance to

some other important diseases such as leaf rust, yellow rust or powdery mildew.

Susceptibility of Global Wheat Germplasm to P. graminis tritici Race Ug 99 Present in East

Africa

Race Ug 99, first identified in Uganda during 1999, is the only known race of P. graminis

tritici that has virulence for gene Sr 31 from rye (Secale cereale). Later this race was designated

as TTKS by Wanyera et al. (2006) using the North American nomenclauture system.

Unfortunately, race Ug 99 not only carries virulence to gene Sr 31 but also this unique virulence is

present together with virulences for most of the genes of wheat origin and virulence for gene Sr 38

introduced in wheat from Triticum ventricosum that is present in several European and Australian

cultivars and a small portion of new CIMMYT germplasm (Table 1).

Predicted patterns of movement of airborne pathogens are filled with uncertainty, although

advances in air-borne modeling and prediction are offering some interesting new insights.

Typically, most spores will be deposited close to the source, however long-distance dispersal is

well documented, with three principal modes of dispersal known to occur.

The first mode of dispersal is single event, extremely long-distance (typically cross-continent)

dispersal that results in pathogen colonization of new regions. Dispersion of this type is rare under

natural conditions and by nature inherently unpredictable.

Assisted long-distance dispersal, typically on traveller’s clothing or infected plant material,

is another increasingly important is another increasingly important element in the colonization of

new areas by pathogens. Despite strict phytosanitary regulations, increasing globalization and air

travel both increase the risk of pathogen spread.

The second major mode of dispersal for pathogens like rusts is step-wise range expansion.

This typically occurs over shorter distances, within country or region, and has a much higher

probability than the first described dispersal mode. This probably represents the most common or

normal mode of dispersal for rust pathogens. A good example of this type of dispersal mechanism

would include the spread of yellow rust by a Yr9-virulent race of P. striiformis that evolved in

eastern Africa and migrated to South Asia through the Middle East and West Asia in a step-wise

manner over about 10 years, and caused severe epidemics in its path.

The third mode of dispersal, extinction and re-colonization, could perhaps be considered a


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sub-mechanism of step-wise range expansion. This mechanism occurs in areas that have

unsuitable conditions of year round survival.

Race Ug99 was first detected in Uganda in 1999. Following its detection, inverstigations in

neighbouring countries in East Africa revealed that the same race may have migrated to sites in

the Rift Valley province of central Kenya by 1998/1999, with subsequent advancement to site in

Eastern Kenya by 2001. In 2003, race Ug 99 was detected in Ethiopia with 2005 reports from at

least six dispersed site locations. Available evidence suggests that Ug99 is now established in the

eastern African highlands and spreading.

The East African highlands are a known ‘hot-spot’ for the evolution of new rust races. The

favourable environmental conditions, plus the presence of host plants year-round all favour the

buildup of pathogen populations. Available evidence emerging from the East African countries

indicates that Ug99 has exhibited a gradual step-wise range expansion, following the predominant

west-east airflows.

A major concern is that a significant proportion of global wheat germplasm is potentially at

risk from race Ug99. Reynolds and Borlaug estimated that this area might amount to 50 million ha

of wheat grown globally i.e., about 25% of the world’s wheat area. Germplasm with resistance to

Ug 99 is available, but for many parts of the world, material of this type is not present in varieties

grown in farmers’ fields. Major questions that now arise are: how likely is it that Ug 99 might

spread, where Ug99 might spread to, and what the likely consequences of any movement are.

Potential Migration Paths for Race Ug99

Most evidence, albeit circumstantial, indicate that Ug 99 is likely to spread beyond the

borders of the three East African countries in which it is currently present. The sheer mobility of

rust spores led an international panel of rust experts to conclude that it is only a matter of time until

Ug99 reaches across the Saudi Arabian Peninsula and into the Middle East, South Asia, and

eventually, East Asia and the Americas’. In addition, there is documented evidence connecting

East Africa with West and South Asia for migration of rust races of East African origin.

Strategies to Mitigate the Risks of Losses From Epidemics Caused by Race Ug 99

The best control strategy is to identify resistant wheat genotypes that can adapt to the

prevalent environments in these countries, and release them after proper testing while

simultaneously producing the seed. An aggressive strategy to promote these resistant cultivars in

farmer’s fields is the only viable option as resource-poor farmers in most of East Africa, except

some commercial farmers in Kenya, can not afford to use chemical control. A reduction in disease

pressure in East Africa will also reduce chances of migration beyond the region.

Reducing the area planted to susceptible cultivars in the Arabian Peninsula, North Africa,

Middle East and West and South Asia is also the best strategy if major losses are to be avoided

when race Ug99 migrates to these areas. The ‘Global Rust Initiative’, launched during 2005 and

led by CIMMYT in partnership with ICARDA and various National and Advanced Research

Institutions, is using the following strategies to reduce the possibilities of major epidemics:


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1) monitoring the spread of race Ug 99 beyond eastern Africa

2) screening of released cultivars and germplasm for resistance

3) distributing sources of resistance worldwide for either direct use as cultivars or for

breeding, and

4) targeted breeding to incorporate diverse resistance genes and adult plant resistance into

high-yielding adapted cultivars and germplsm (www.globalrust.org).

Table 2: Frequency of wheat cultivars and advanced breeding lines of different origins for

their field response to Ug99 race of the stem rust pathogen at Njoro, Kenya during 2006

Country/Institution Response and frequency Total

Resistant Moderately resistant

Moderately susceptible and susceptible

Bangladesh 0 3 81 84

China 1 1 116 118

Egypt 3 0 146 149

India 16 7 79 102

Iran 1 1 98 100

Khazakstan 2 1 83 86

Nepal 1 1 103 105

Pakistan 0 6 99 105

Russia 0 1 34 35

Turkey 14 2 69 85

CIMMYT-Irrigated4 94 56 400 550

CIMMYT-Semiarid4 50 9 161 220

CIMMYT-High Rainfall4 11 6 99 116

Race-specific Resistance Genes

A large portion of the highly resistant germplsm from South America, Australia and

CIMMYT possess Sr 24. There are three distinct Sr24-carrying translocations: the original one

linked to a gene for re grain colour, the shorter segment with white grain, and a third segment

where a very small segment has been retranslocated onto chromosome 1BS. In all three

segments both Sr24 and Lr 24 are present together. Therefore, selection for Lr24 with avirulent

leaf rust isolates can be used as an indirect selection strategy. This gene would look like an

attractive candidate for future breeding efforts; however it must be used in combination with other

effective resistance genes because virulence to Sr 24 is already known in South Africa and India.

Gene Sr 36 derived from Triticum timopheevi, exhibits an immunity (no symptoms) to race

Ug99 at both seedling and adult plant stages. The gene occurs in a high frequency in US soft

winter wheat. Although races with virulence for Sr 36 are common, it could be used effectively as a

component for Ug99 resistance breeding.

Breeding strategies for resistance to P. graminis tritici Race Ug99

The fastest way to reduce the susceptibility of important wheat cultivars and the best new

germplasm is to systematically incorporate diverse sources of resistance into them through limited

or repeated backcrossing. To transfer two or more effective resistance genes into an adapted

cultivar the better crossing strategy would be to first cross the resistance sources and then cross


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the F1 plants with the adapted cultivar. Molecular markers can then be used to select top-cross

plants that have desirable agronomic features and carry the targeted resistance genes.

The strategy adopted at CIMMYT is to transfer the adult-plant resistance from Pavon 76,

and a few other wheats identified so far, to a range of important CIMMYT wheat germplasm by

using the ‘single-backcross selected-bulk’ breeding approach. In this strategy the resistance

sources are crossed with the adapted high-yielding wheats and then a single backcross is made

with the recurrent parent to obtain about 400 BC1 seeds. BC1 plants were then selected for desired

agronomic features and resistance to leaf and yellow rusts, and harvested as bulk. Large F2

populations of about 2500 plants will be grown and plants will be selected in Mexico for agronomic

traits and resistance to other diseases and harvested as bulk. A similar selection will be practiced

in the F3 generation to obtain F4 populations. At this stage we will try to select for adult-plant

resistance by growing densely sown F4-buld population is Kenya or Ethiopia, under high stem rust

pressure created by inoculating with Ug99 race. Populations will be bulk harvested and plumper

grains selected to grow F5 generation in Mexico. Because stem rust affects grain filling, we expect

that plants with insufficient resistance will have shriveled grains. Moreover, by F4 generation

enough homozygosity is achieved for the selection of additive resistance genes. Individual plants

with desired agronomic features and resistance to other diseases will be selected in the F5

generation and those with good grain characteristics will be grown in F6 as hill plots or short rows

in Kenya or Ethiopia as well as small plots in Mexico for final selection. Finally, the resistant F6

plots will be harvested for conducting yield trials in the following crop season. The same

methodology is also proposed to transfer resistance from old, tall Kenyan cultivars into adapted

semidwarf wheats. The proposed approach is expected to rebuild the durable resistance in

modern wheat germplasm. Genetic analyses will be necessary to understand the number and type

of resistance genes involved in sources contributing the adult plant resistance. Genomic locations

of minor, additive resistance genes will be determined through molecular mapping. Such

information will be useful to establish and enhance genetic diversity for minor genes.

Rapid Seed Multiplication

Once UG99 resistant wheat varieties are nationally or regionally registered and ready for

release, a national strategy should be in place for the seed multiplication and distribution of quality

seed of rust resistant varieties to replace rust susceptible varieties in high areas or hot spots. As a

stating point, the initial target for rapid seed multiplication is 10% of the wheat production area. In

most countries this can be accomplished in 3-4 generations (see Table 2). The actual targets for

rapid seed multiplication will depend on the actual and potential threat of UG99 that will be

elaborated as part of the contingency planning and surveillance system.

Table 1: Planting rate of 100kg/ha with varying yields (3T/ha, 4T/ha and 6T/ha)

Generation Qty of seed produced in Tons with different Seed Multiplication Ratio

1:30 1:40 1:60

Initial seed Qty 0.05 0.05 0.05

First 1.5 (0.5 ha) 2.0 (0.5 ha) 3.0 (0.5 ha)

Second 45 (15 ha) 80 (20 ha) 180 (30 ha)


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Third 1,350 (450 ha) 3,200 (800 ha) 10,800 (1800 ha)

Fourth 40,500 (13,500 ha) 128,000 (32,000 ha) 348,000 (108,000 ha)

Fifth 1,215,000 (405,000 ha)

5,120,000 (128,0000 ha)

38,880,000 (648,0000 ha)

To provide an idea of the number of generations, area needed for seed multiplication and

area the seed can cover at various multiplication factors, the above tables will provide some basic

information of a seed multiplication system starting with 50kg of nucleus seed.

S. No. Country Area under Wheat

cultivartion 2007

10% of the

wheat area

% Area that will be covered after 4 generations with following

Multiplication Factor

1:30 1:40 1:60

1. Afghanistan 2,190,000 219,000 18.4 58.4 100

2. Algeria 1,785,000 178,500 22.6 71.7 100

3. Armenia 113,300 11,330 100 - -

4. Azerbaijan 486,990 48,699 83.4 100 -

5. Bangladesh 805,000 80,500 50.3 100 -

6. China 30,000,000 3,000,000 1.4 4.3 21.6

7. Eqypt 1,139,000 113,900 35.6 100 -

8. Ethiopoia 1,351,000 135,100 29.9 94.7 100

9. Georgia 61,000 6,100 100 - -

10. India 28,035,000 2,803,500 1.4 4.6 23.1

11. Iran 6,400,000 640,000 6.3 20.0 100

12. Iraq 531,210 53,121 76.2 100 -

13. Jordan 30,000 3,000 100 - -

14. Kenya 150,000 15,000 100 - -

15. Kyrgyzstan 354,500 35,450 100 - -

16. Lebanon 48,000 4,800 100 - -

17. Libya 257,000 25,700 100 - -

18. Morocco 1500,000 150,000 27.0 85.3 -

19. Nepal 472,000 47,200 85.8 100 -

20. Oman 275 27.5 100 - -

21. Pakistan 8,494,000 849,400 4.8 15.1 76.3

22. Saudi Arabia

462,000 46,200 87.7 100 -

23. Sudan 250,000 25,000 100 - -

24. Syria 1,850,000 185,000 21.9 69.18 100

25. Tajikistan 330,000 33,000 100 - -

26. Tunisia 974,000 97,400 41.6 100 -

27. Turkey 8,600,000 860,000 4.7 14.9 75.3

28. Uganda 11,000 1,100 100 - -

29. Uzbekistan 1400,000 140,000 28.9 91.4 100

30. Yemen 114,030 11,403 100

This second table focuses on providing an idea of indicative quantities of seed that may be

needed in each country. A tentative target of seed to cover 10% of the total area in wheat is

included. In addition the percentage of the area that can be covered by 4 generation of seed

production a multiplication factor of 30, 40 and 60 demonstrates the need to undertaken intensive


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wheat seed production in order to reduce the time to reach the target quantities.

Gene Deployment: Indian Experience

Gene deployment is the strategic usage of resistance genes over a large area to

reduce the threat of epidemics.

Gene deployment schemes with aim to prevent large-scale build up of wheat rusts

were also proposed in India.

In order for the gene deployment to be effective, information on some of key areas

- Pathogenicity survey in the country,

- Information on virulence of exogenous pathotypes

- Epidemiological studies must be acquired and made available.

In order for the gene deployment to be effective, it is very essential that role of

exogenous inoculum is ascertained. Breakdown of Kalyansona, Sonalika and Yr9

resistance against stripe rust was traced to Eastern Africa, Turkey, Syria, Iran and

Pakistan. Another challenge now is that similar route of migration has also been predicted

for Ug99.

A successful, though unintentional, deployment for stem rust resistance is the large scale

cultivation of HD2189 in Peninsular India. Presently, this cultivar is resistant to Indian stem

rust pathogen. Another Sr31- cultivar (DWR162) being cultivated in Karnataka or Nilgiris is

not able to multiply as it lands on the resistant gene. Consequently, three popular cultivars

of Central Zone namely Lok-1, Sujata and WH147, though susceptible but are protected

against any transported inoculum.

Chemical and Cultural Management of TTSK (Ug99) of Wheat Stem Rust Pathogen in

Kenya

While resistant is the most effective method of controlling stem rust, there are no

commercial varieties in Kenya with adequate resistance. Therefore, fungicides as foliar or

seed treatments will play a role in the integrated management of the disease until new

varieties with improved resistance are released.

Stem rust epidemics are causing grain losses of up to 70% in experimental plots

and over 70% in farmer’s fields. This is yield of sprayed vs. unsprayed wheat crop.

Spraying only reduces but does not eliminate the disease. It is therefore possible to get

yield losses higher than this when relative to a clean crop. In the year 2007, farmers who

never controlled the disease at all, lost 100% of their crop regardless of the variety.

Short term control of stem rust can be achieved with standard application of

fungicides, provided the infection is not severe. Some of the foliar fungicides

recommended for the control of yellow and leaf rusts can also be used to reduce/suppress

the stem rust disease. Because most farmers are not able to identify the rust, it is

recommended to apply to apply two sprays, 60 days and 75-78 days respectively, after

planting.


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REFERENCES

1. Mclntosh R.A. The role of specific genes in breeding for durable stem rust resistance in wheat and triticale. In: symonds NW, Rajaram S(eds) “Breeding strategies for resistance to the rust of wheat” CIMMY, Mexico 1988 p 101-08.

2. Ravi P. Singh et al Current status, likely migration and strategies to mitigate the threat to wheat production from Race Ug 99 of stem rust. CAB Rev. 2006, 1, no. 054.

3. Singh R.P. et al Wheat rust in Asia: meeting the challenges with old and new technologies. Proc. 4

th International Sciences Congress, Brisbane, Australia 26 Sept-1 Oct. 2004.

4. S.S. Xu et al Evaluation and characterization of seedling resistance to stem rust Ug 99 races in wheat alien species derivatives. Published online Oct 2009. Crop Science.

5. Wanyera R.; Kinyua M.G.; Jin, Y; Singh, R.P. The spread of stem rust with virulence on Sr 31 in wheat in Eastern Africa. Plant Diseases 2006: 90-113


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Plant Diseases in Changing Climate

K.S. Hooda, Kedar Nath, Shikha Sharma, Meena Shekhar and Sangit Kumar Directorate of Maize Research, Indian Council of Agriculture Research, Pusa Campus, New Delhi 12

Introduction

Greenhouse gas concentrations in the atmosphere are being altered by human activities,

thus causing global climate change. These activities, intensified after the Industrial Revolution at

the end of the eighteenth century, result from the use of natural resources such as burning of fossil

fuel, deforestation and other land use changes. The atmospheric concentration of carbon dioxide

(CO2) has reached levels significantly higher than in the last 650 thousand years (Siegenthaler et.

al., 2005). Similar trends have been observed for methane (CH4), nitrous oxide (N2O), and other

greenhouse gases (Spahni et. al., 2005; IPCC, 2007). The average global surface temperature

has increased by 0.2°C per decade in the past 30 years (Hansen et. al., 2006). Theophrastus

(370-286 B.C.) observed that cereals cultivated in higher altitude regions exposed to the wind had

lower disease incidence than cereals cultivated in lower altitude areas. Agrios (2004) estimated

that annual losses by diseases cost US$ 220 billion.

Geographical distribution of plant pathogenic prokaryotes, like other pathogens occurring in

plants, is predominantly influenced by several factors such as: local climate, distribution of host

plants, dispersal ability of pathogens, presence of animal vectors, and adaptability of pathogens to

local conditions, the ability of pathogens to infect new host plants, and resistance of local cultivars

(Garrett et. al., 2006).

There is consensus among climatologists that global warming is occurring and refers to the

gradual increase in global average surface temperature, as one of the consequence of radiative

forcing caused by anthropogenic (created by people or caused by human activity) emissions.

However, confidence in attributing some observed climate change phenomena to anthropogenic or

natural processes is limited by uncertainties in radiative forcing, as well as by uncertainty in

processes and observations (Bater et. al., 2008).

Climate Change in Agriculture Sector

Agriculture sector is particularly sensitive to climate change. From an agricultural

perspective, macroclimate can be defined as the climate above or .outside a plant canopy, in

contrast to microclimate, the climate within the plant canopy. While many events in plant disease

cycles occur within the plant canopy, the macroenvironment often exerts a major influence on

disease occurrence and pathogen dissemination (Gleaseon 2000).

Role of Environment in Causing Plant Diseases

Plant Disease Triangle:


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The three legs of the triangle – host, pathogen, and environment – must be present and

interact appropriately for plant disease to result. If any of the 3 factors is altered, changes in the

progression of a disease epidemic can occur.

Nowadays, the environment can influence host plant growth and susceptibility; pathogen

reproduction, dispersal, survival and activity; as well as host-pathogen interaction (Gaumann,

1950).

Impact of Rising Temperatures on Diseases

Temperature has potential impacts on plant diseases through both the host crop plants and

the pathogens. Research has shown that host plants such as wheat and oats become more

susceptible to rust diseases with increased temperature; but some forage species become more

resistant to fungi with increased temperature (Coakley et. al., 1999). Generally, fungi that cause

plant disease grow best in moderate temperature ranges. For example, predictive models for

potato and tomato late blight (Phytophthora infestans) show that the fungus infects and

reproduces most successfully during periods of high moisture that occur when temperatures are

between 7.2°C - 26.8°C (Wallin et. al., 1950).

Bergot et. al., 2004 have used a GCM to simulate the potential impacts of climate change

on the expansion of Phytophthora cinnamomi in oak, by modeling phloem temperature of infected

trees to evaluate overwintering probabilities. For the downy mildew of grape, caused

by Plasmopara viticola. Salinari et. al., 2006 used GCM to evaluate disease pressure.

Impact of Rising CO2 levels on Diseases

Increased CO2 levels can impact both the host and the pathogen in multiple ways.

Researchers have shown that higher growth rates of leaves and stems observed for plants grown

under high CO2 concentrations may result in denser canopies with higher humidity that favor

pathogens. Lower plant decomposition rates observed in high CO2 situations could increase the

crop residue on which disease organisms can overwinter, resulting in higher inoculum levels at the

beginning of the growing season, and earlier and faster disease epidemics. High

CO2 concentration results in benefits for plant growth, although there might be differences among

species. CO2 enrichment promotes changes in plant metabolism, growth and physiological

processes. There is a significant increase in the photosynthetic rate and a decrease in the

transpiration rate per unit leaf area, while total plant transpiration sometimes increases, due to the

larger leaf area (Jwa & Walling, 2001; Li et. al., 2003).

Karnosky et. al., 2002 also observed that the effects of O3 on leaf surface properties

resulted in increased incidence of this rust. Osswald et. al., 2006 investigated whether elevation of

CO2 (400 up to 700 ppm) and/or ozone (ambient or two-fold ambient) resulted in a change in

susceptibility of potato plants infected with Phytophthora infestans.

Using mathematical models, Carter et. al., 1996 simulated climate change in Finland and

concluded that warming will expand the cropping area for cereals by 2050 (100 to 150 linear km

per Celsius degree increase in mean annual temperature); furthermore, higher yields are expected


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with higher CO2 concentration. In this scenario, potato cropping will also be benefited with an

estimated 20 to 30% increase in yield. However, a new distribution of the potato cyst nematode

(Globodera rostochiensis) is also predicted.

Manning and Tiedemann, 1995 observed an upward trend in diseases. They analyzed the

potential effects of higher CO2 concentration on plant diseases, based on the plant responses to

this new environment. Increased carbohydrate contents can stimulate the development of sugar-

dependent pathogens, such as rusts and powdery mildews. Increases in canopy density and plant

size can promote higher growth, sporulation and spread of leaf infecting fungi, which require high

air humidity, but not rain, as rusts, powdery mildews and leaf necrotrophs. The reduction in

stomatal opening can inhibit stomata- invading pathogens, such as rusts, downy mildews and

some necrotrophs.

Drought stress and disease stress may have additive effects on plants, as observed for

infection by Maize dwarf mosaic virus (Mayek-Perez et. al., 2002 and Macrophomina phaseolina

(Olson et. al., 1990), may cause more deleterious effects on their hosts under drought conditions,

though it is unclear whether this is because of increased infection rates under drought or because

of increased impacts per infection event.

Mayek-Perez et. al., 2002 suggest that the concentration of carbohydrates in host tissues

as a result of drought stress may benefit pathogens such as M. phaseolina that can survive in

extremely dry soils. High CO2 concentration results in benefits for plant growth, although there

might be differences among species. Several authors reached the same conclusions with different

crops, natural ecosystems and forest species.

Impact of Moisture on Plant Diseases

Moisture can impact both host plants and pathogen organisms in various ways. Some

pathogens such as apple scab, late blight, and several vegetable root pathogens are more likely to

infect plants with increased moisture. Other pathogens like the powdery mildew species tend to

thrive in conditions with lower (but not low) moisture (Coakley et. al., 1999).

Major Taxonomic Groups of Pathogens Causing Plant Emerging Infectious Diseases (EID)

Viruses, fungi and bacteria are the major pathogens causing plant EIDs. Viruses cause just

under half (47%) of the reported plant EIDs which is a similar percentage to that for human (44%

[Taylor et. al., 2001]) and wildlife (43%) EIDs (Dobson et. al., 2001). However, bacteria cause a

lower proportion (16%) of plant EIDs compared with human (30% [Taylor et. al., 2001 ]) or wildlife

(w30% [Dobson and Foufopoulos (2001) ]) EIDs and fungi represent a higher proportion (30%) of

plant EID pathogens when compared with those of humans (9% [Taylor et. al., 2001]) or wildlife

(!10% [Dobson et. al., 2001]).

Climate Change as a Driver of Emerging Infectious Diseases of Plants

Range expansion of the grey leaf blight of corn, caused by the fungus Cercospora zeae-

maydis, was first noticed during the 1970s, and, in the past two decades, has become the major

cause of corn yield loss in the USA. Aflatoxin, a compound that lowers corn quality and which is a


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health risk to humans, is related to drought conditions and its concentration is raised during crop-

water deficits, which favour the growth of the fungus Aspergillus flavus.

Plant Diseases in Relation to Climate Change

It was emphasised by Coakley et. al., 1999 that most of what has been said about plant

disease in relation to climate change is based on qualitative, rule-based reasoning. For example, it

seems plausible but not sure that (i) increased air temperature would result in a poleward

expansion of the geographical range of pathogens and in more generations per year; (ii) elevated

winter temperatures would increase survival and hence the amount of initial inoculum in many

pathosystems; (iii) and that greater continental dryness during summer would reduce risk of

infection by pathogens that require leaf wetness or saturated soils for infection. In case of vector-

borne diseases, climate influences the spatial distribution, intensity of transmission, and

seasonality of diseases transmitted by vectors. Climate change can have positive, negative or

neutral impact on individual plant-bacterial pathogen interactions.

Anonymous (2008) reported that Rhizoctonia solani produced symptoms in the form of

scattered lesions after 3 days of inoculation at temperature range 26.0- 33.30C and relative

humidity 84- 86 per cent as compared to temperature range 8.8-200C and relative humidity 86-92

per cent after 20 days of inoculation.

According to Chakraborty et. al., 2000a, more aggressive strains of pathogen with broad

host range, such as Rhizoctonia, Sclerotinia, Sclerotium and other necrotrophic pathogens can

migrate from agroecosystems to natural vegetation, and less aggressive pathogens from natural

plant communities can start causing damage in monocultures of nearby regions.

Gioria et. al., 2008 showed a prediction for the main tomato diseases and argued that

climate change will not be favorable for the occurrence of late blight (Phytophthora infestans),

verticillium wilt (Verticillium albo-atrum), and white mold (Sclerotinia sclerotiorum); and will not alter

the importance of the tomato mosaic caused by the tomato mosaic virus (ToMV) and the septoria

leaf spot (Septoria lycopersici). In contrast to those diseases, the importance of powdery mildew

(Leveilula taurica) will increase in all tomato production regions across the country, just as the

importance of early blight (Alternaria solani), fusarium wilt (Fusarium oxysporum f.sp.lycopersici),

bacterial wilt (Ralstonia solanacearum), tomato spotted wilt virus - TSWV, tomato chlorotic spot

virus - TCSV, groundnut ring spot virus - GRSV, Chrysanthemum stem necrosis virus - CSNV and

yellow leaf curl virus (Geminivirus).

Emergence of Heat-loving bacteria

Most heat-loving plant pathogenic bacteria that have emerged as serious problem

worldwide belong following bacterial plant pathogens: Ralstonia solanacearum, Acidovorax

avenae subsp. aveane, and Burkholderia glumea.

Climate Change and Plant Health Care System

The predicted changes in future climate may affect growth of crop plants and their

interaction with plant pathogens. Climate change is likely to be a gradual process that will give


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researchers, plant breeders, plant health care practitioners, managers and farmers some

opportunity to adapt. Both predicted (and unpredicted) disease consequence of climate change on

plant health can most likely be minimised by such manners as follows: (i) to build a solid

knowledge base on the impact a consequence of climate change for various parts of the world; (ii)

to determine the potential for adaptation under potential changes in pathogen pressure due to

climate change (or other factors); (iii) to maintain a high index of suspicion for changes in the plant

pathosystem; (iv) to monitor systematically occurrence of diseases and animal pests in each field

and region and keep records of severity, frequency over time; (v) to develop new varieties adapted

to changed climate through traditional or transgenic methods; (vi) the farm advisory system could

be used not only to disseminate knowledge but also to adopt and introduce the new integrated

control of organisms injurious to plants.

Conclusions

1. The precise impacts of climate change on insects and pathogens is somewhat uncertain

because some climate changes may favor pathogens and insects while others may inhibit a

few insects and pathogens.

2. The preponderance of evidence indicates that there will be an overall increase in the number

of outbreaks of a wider variety of insects and pathogens.

3. The possible increased use of fungicides and insecticides resulting from an increase in pest

outbreaks will likely have negative environmental and economic impacts for agriculture.

4. The best economic strategy for farmers to follow is to use integrated pest management

practices to closely monitor insect and disease occurrence. Keeping pest and crop

management records over time will allow farmers to evaluate the economics and

environmental impact of pest control and determine the feasibility of using certain pest

management strategies or growing particular crops.

5. Global climate change affect humans, livestock and wildlife as plant diseases impact

negatively on human wellbeing through agricultural and economic loss, and also have

consequences for biodiversity conservation.

6. The analysis of the potential impacts of climate change on plant diseases is essential for the

adoption of adaptation measures, as well as for the development of resistant cultivars, new

control methods or adapted techniques, in order to avoid more serious losses.

Future Thrust

The impacts on abiotic diseases associated with the occurrence of extreme values of

environmental variables need to be discussed, in spite of an expected increase in their incidence

so it could be study.

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26. Taylor, L.H. et al. (2001) Risk factors for human disease emergence.Philos. Trans. R. Soc. Lond. Ser. 356, p. 983–989.

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Evaluation and Selection of Promising Trichoderma Isolates For the Management of Soil Borne Fungal Plant Pathogens

A.K. Tewari


Dual culture Method: This method is used for testing mycoparasitic activity of antagonist. Pour

15-20ml sterile PDA in sterile plates amended with Chloromphenicol (100 mg/lit.) or streptomycin

(100mg/lit). Place the bits (5mm) of the test pathogen as well as antagonist on the PDA plates

opposite to each other from 1.0 cm from the periphery of plates (if both are fast growing) or place it

2-3cm apart (if both are slow growing). Incubate the plates at 25+10C for desired duration.

Observe the plates regularly.

I. In-vitro evaluation and selection

(A). Mycoparasitism:

In mycoparasitism the pathogen stops growing upon contact with the antagonist and its

mycelium begin to lyse backwards and the antagonist continue to grow over the test fungal

pathogen.

Observations

First observation should be taken just after contact and measure the growth of the

pathogen in dual culture.

After contact, observations should be taken regularly at 3 day interval until the antagonist

completely parasitizes the test pathogen or antagonist stops growing over the test pathogen.

Calculate the percent inhibition (parasitized growth) of the test pathogen by comparing the growth

of the pathogen (after parasitization) with its initial growth (just after contact). To see the hyphal

interaction small bits of mycelium can be taken from interaction zone and observe under

microscope.

Mycoparasitism of Sclerotial plant pathogens

Collect freshly non-dried sclerotia , surface disinfested and wash in sterile distilled water.

Immerse these sclerotia in an aqueous spore or mycelial suspension of the antagonist for 1-5 min.

Place these sclerotia in culture plates containing sterile moist sand. Incubate it for 1-4 week at 25-

280C. After desired period of time observe colonization of antagonist on decayed sclerotia

B). Antibiosis:

The antagonists that has antibiosis effect (formation of zone of inhibition) in dual culture

must be further tested using cellophane membrane and cell free culture filtrates

Non Volatile compounds:

1. Cellophane membrane method

Place sterilized disk (90mm) of a cellophane membrane on culture medium. An agar disk of

antagonistic fungus is placed at the centre of the cellophane membrane. 3-4 days after incubation,

remove the cellophane membrane along with the growth of antagonist. An agar disk from culture


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of actively growing test pathogen is transfer to the position previously occupied by the antagonist.

Test pathogen grown on PDA plates serves as check. The radial growth of the test pathogen is

recorded 3-4 days after incubation and compare with check. The reduction in radial growth of the

test pathogen shows production of non-volatile compounds by the antagonist.

2. Cell free culture filtrate

The antagonist is grown on potato broth medium either in stationary or in shake culture.

After sufficient mycelium growth the mycelium and other cells are removed by filtration through

filter paper and then sterilized by passing through G1,G3 and G5 sintered glass filter. The cell free

sterile culture filtrate is tested for efficacy of antagonist against the fungal pathogens by following

ways.

a. Assay in solid medium

i. Food Poison technique

ii. Filter paper disc method

iii. Agar well method

b. Assay in liquid medium

c. Spore germination test

a. Assay in solid medium

i. Food Poison technique

Mix sterile cell free culture filtrate in sterilized PDA flasks (various concentrations)

and pour in Petri dishes. Inoculate the test pathogen at the centre of the PDA plates. Pathogen

on PDA plates without culture filtrate serves as control. Incubate at 25+10C for desired

duration. Per cent inhibition was calculated by measuring the radial growth of the test fungus in

amended medium and compare with check.

ii. Filter paper disc method

Pour 15ml of a PDA in sterile Petri plates. After solidification uniformly spread 4ml of 1.5%

water agar, seeded with 104 spores/ml of the test pathogen. 4-6 filter paper dics (1-2 cm dia,

autoclaved and dried) soaked in culture filtrate and dried, are place on the seeded agar medium

from 1-1.5cm periphery of the plates. After incubation measure the zones of inhibition around the

filter paper .

iii. Agar-well Method

Prepare PDA plates as above. Remove Agar plugs at a distance of 1-2 cm from the

periphery of the PDA plate with the help of cork borer of 1-2 cm dia. Fill the wells with a known

concentration and standard quantity of the cell free culture filtrate. After incubation, measure the

zones of inhibition around the wells.

b. Assay in liquid medium

Add sterile culture filtrate at desired concentration in a known volume of potato broth and

mix well. The flasks containing medium is inoculated with a 5 mm discs (2 no.) of the test

pathogen. Incubate until sufficient growth has occurred in check (medium without culture filtrate)


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flask. Measure fresh and dry weight of the test pathogen growth and calculate per cent inhibition

c. Spore germination test

Place 0.2-0.5ml of the desired concentration of the cell free culture filtrate in the wells of a

cavity slide and dry at room temp. The same amount (0.2-0.5ml) of spore suspension of the test

pathogen (5X103 spores/ml) is added over the dried culture filtrate and mix well with help of a

glass rod. Incubate it in a humid chamber at 25-280C. Spore germination and characteristics of the

germ tube is recorded at 12 hr interval and compare with check (cavity slides without culture

filtrate) and calculate per cent inhibition.

Volatile compounds:

Grow antagonist on PDA plates. 3-4 days after incubation, inoculate the test pathogen in

separate PDA plates. Place inoculated test pathogen (upper) on the 3-4 days old antagonistic

plates (lower) by removing lids of both the plates. Make pair by binding both the plates opposite to

each other with parafilm. Incubate the paired plates until full growth has occurred in check plates

(inoculated with test pathogen alone). Calculate the per cent growth inhibition by measuring the

growth of the test pathogen and comparing it with check plates. The reduction in radial growth of

the test pathogen shows production of volatile compounds.

C. Compatibility of fungal antagonist with commonly used chemicals:

‘Food Poison Technique’ is used to test the compatibility of fungal antagonist fungicides,

insecticides, herbicides and other chemicals to be commonly used for plant health.

II. Evaluation and selection of promising Trichoderma isolates in glasshouse

1. Disease Management

A. Seed treatment

B. Seedling dip treatment

C. Soil application

D. Soil drenching

Observations

i. Disease incidence / Disease severity

ii. Population dynamics (CFU /g soil at 7 days interval)

2. Systemic induced resistance

A. Seed treatment

B. Seedling dip treatment

C. pre-spraying

Observations:

a. Peroxidase,

b. Phenyl alanine ammmonia lyase

c. Polyphenol oxidase

d. H2O2 content

e. Phenol content


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f. Superoxide dismutase

g. Lypoxygenase

h. Chlorophyll content

i. Membrane stability index

3. Plant growth promoter

Observations:

a. Biomass of plant

b. Root length & weight

c. Shoot length & weigh

III. Qualitative parameters for formulation

a. Spore concentration

b. Shelf life (Viability)

c. Food for initial establishment

IV. Field Testing

V. Maintenance of culture

Selection of promising Trichoderma isolates for commercialization

i. Select broad spectrum isolate.

ii. Evaluate performance under the range of environmental conditions.

iii. Evaluate formulations.

iv. Evaluate application methods.


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Major Seed Pieces Transmissible Diseases of Sugarcane and their Management by Three Tier Seed Programme

R.K. Sahu


Sugarcane is one of the most energy rich plant and most efficient converters of solar

energy in to not only in sugars (Sucrose) but also in other renewable forms of energy. Basically, it

is an tropical region crop but grown very successfully in subtropical regions under diverse agro

ecological situation for various agro industrial purposes through out the country.

Out of total sugarcane produced, it is estimated that 70% is used in sugar industry whereas

18% is used for the production of Gur (Jaggery), Khandsari, Rav and Juice and 12% is used as

seed. In beginning the plant was domesticated only for its sweet stem but later on it was used for

various other purposes. Now a days the by products of sugar industry are of much significant.

Products like Bagasse, Molasses, Filter press cake or press mud which are generated during

sugar production are used as raw material for the production of paper, different types of boards

making, rayan, liquir, alcohal, gasohol and other derivatives of alcohal and chemicals, animal feed,

antibiotic, biofertilizer and raw material for generating electricity. Due to crisis and limited

availability of the mineral oil/crude oil, it is a hope for future ecofriendly fuel and may be a

substitute. Among several countries Brajil is one where use as fuel in transportation has

tremendously increased. Govt. of India in 2009 has also decided to mix 5% Alcohal in petrol.

It was estimated that in a typical sugar mill 100(t) of sugarcane, on an average produce 10

ton of sugar (sucrose), 4(t) of molasses from which ethanal is produced, 3(t) of press mud which is

converted in to biofertilizer, 30(t) of bagasse used for co-generation of power to yield 1,500 Kw

electricity and for manufacturing of paper. About 30(t) of cane tops and leaves are generally left in

the field which again has multifold use like animal fodder. Dry leaves are used in thaching the huts

and several other means and remaining is used for recycling in the field (mulch). Sugarcane thus

play a major role in the economy of sugarcane growing areas in particular and nation as whole and

hence increasing sugarcane production will certainly bring the smiles in the face of farmers and

other stake holders associated with this crop directly or indirectly.

The cane area estimated during 2006 were 48.32 lakh ha and 51.54 lakh ha in 2007. In

2005-06 sugar production was 19.32 MT whereas in 2006-07 it was 28.36 MT and in 07-08 it was

26.35 MT. As the population is increasingly increasing day by day and is expected to be in

between 1237 to 1262 million in the year 2011 and in between 1504 to 1690 million in year 2025.

Correspondingly the land resources, what we are having are condensing day by day because of

several uses especially in industries, infrastructure facility creation and residential purposes. To

cater the need of this growing population, we have the only way out to increase the productivity of

the crop hence forth. Productivity of southern & Maharashtra is 90-110 t/ha whereas in the major

sugarcane producing Northern states (Uttar Pradesh, Uttarakhand, Punjab and Haryana which


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accounts for 67% area of the country) the productivity of these states is ranging some where 43-60

t/ha than the national average 67 t/ha which in lower and is of major concern.

As the vagarics of agroclimatic condition and many biotic & abiotic stress sugarcane crop is

suffering. Among serval biotic stresses and constraints responsible for low cane production &

productivity, diseases are one of the major constraints causing 19-20% losses. If we can minimize

this loss, then it will help a lot for sugrpool.

More than 240 disease caused by Fungi, bacteria, Virus, Phytoplasma, Nematodes etc

have been reported from various parts of the world causing low to severe looses every year. Out

of these a dozen are important in our country which are occurring year after year. Among these

only 7disease (major) which are seed /sett borne are more prevalent and causing moderate to

severe loss depending on the severity and agroclimatic condition, cropping pattern and the

susceptibility of the host.

The diseases of sugarcane which are sett/ seed borne and exerting huge losses are Red

rot, Smut, Wilt, GSD, Mosaic, Ratoon Stunting & Leaf scaled. A short account of these diseases

are given as:

1. Red rot

In India the disease was first recorded in the Godawari Delta of Andhra Pradesh by

Barber in 1901. Presently this disease is of wide occurrence in varying degree where ever the

sugarcane crop is under cultivation in the country & particularly rampant in eastern U.P. &

Northern Bihar making these places as ‘hot spots’. This disease because of its most devastating

nature has made several promising sugarcane varieties obsolete.

The disease is caused by a fungus Colletotrichum falcatum Went. The initial symptoms

appear as third fourth leaves from the top start drying from margin inwards & ultimately entire

leave dry. Mid-rib lesions become conspicuous during monsoon. The lesions usually start as

minute red spots on the upper surface of the mid-rib & further develop forming long lesions. During

later stage, the canes become shriveled and lighter in weight. When the canes are split open

longitudinally, the pith is found reddened accompanied by white transverse patches at right angles.

In advance stage of the disease the red colour may be replaced by dirty brown & white bands look

hazy or unclear. These dried canes often emit sour odour & juice does not set well on boiling.

Diseased seed setts are the main source of survival & spread of the pathogen.

2. Smut

The disease is world-wide in occurrence except Australia, among 121 sugarcane

producing countries. During 1942-43, it assumed devastating epidemic form in Bihar affecting 66%

of the cane area. The causal organism of this disease is Ustilago scitaminea (syn. Sporosorium

scitaminea) which gets transmitted through infected seed setts and can also survive through the

spores fallen on the ground.

Affected plants are characterized by the production of long, whip like structure with black


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dusty mass of spores at apex. During early stage this structure is straight & becomes curved,

several feet in length. Subsequently, the whip remains covered with a bright whitish membrane.

On bursting of membrane the spores come out & healthy plants get infected by air. Such structure

can be observed in flushes: first during the months of May- June and secondly during October-

November. Infected plants often have slender & thin canes (look likes “Narkul” a wild grass) and

become lighter in weight due to drying of canes & sometimes many tillers develop.

3. Wilt

Earlier wilt disease was confined to northern belt of sugarcane particularly Bihar state from

where it spread to U.P., Punjab & Haryana. In Tamilnadu, during 1955-56, the disease caused

considerable damage with 5-80 percent incidence. Similarly during 1959-60 it assumed severe

proportion in Andhra Pradesh where incidence was as high as 100% in cultivar like Co 775.

The disease is caused by a fungus Cephalosporium sachari and is transmitted mainly through

infected seed setts. The fungus can also survive in the soil. This disease commonly occurs with

the infection of red rot & poor crop is more prone to wilt infection. Disease intensity largely

depends upon faulty drainage & prevailing draught or in sufficient moisture conditions in the field.

The most striking symptoms of the disease become apparent late in the season which are

yellowing accompanied by drooping of the top when the crop is ready for harvest, the growth of

plants is held up & the affected canes dry rapidly. In the initial stage of the disease when the canes

are split open, the tissues, particularly of the lowest internodes have a brick-red / dirty red colour in

the form of conical shaped spots. This reddening may be confined to a few internodes or extended

to the entire length of the cane. Such canes dry up, become hollow & there is considerable

reduction in the quality of juice. Disease canes produce characteristic foul odour.

4. Mosaic (Sugarcane mosaic)

In India the disease was first observed in 1927. Subsequently its appearance has been

reported from different sugarcane growing areas in the country. The casual virus belongs to the

potato virus ‘Y’ group and known as Sugarcane mosaic virus (Marmar Sacchri). Infection of this

disease occurs through infected seed setts. In India Rhopalosiphum maidis is the main vector

though Toxoptera graminum. (Schizaphis graminum) has also been demonstrated to be a vector

of SCMV. The virus is also sap transmissible. In India disease losses have been estimated

between 10-20 percent. The disease symptoms characteristically appear on basal portion of

foliage than on the older leaves prominently in the form of yellowish or chlorotic stripes alternate

with green space of the leaf- a mosaic pattern. Considerable increase in chloratic area over the

normal green & appearance of symptoms on the leaf sheath become common features during

advance severe infection yellow stripes also appear on the rind of the internodes & stalks finally

dry up forming ‘sunken’ areas called as canker stage of mosaic. The disease affects both in

quantity of sugar & Jaggery as well as their quality also.

5. Grassy shoot disease (GSD)

The GSD was first observed in 1919 by Barber and reported by Vasudeva in 1955 from


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Belapur, Maharastra. The disease has been recorded in most of the sugarcane growing belt in

India. But since then the incidence is being particularly high in Maharastra and is caused by

Phytoplasma.

The disease is characterized by proliferation of auxiliary buds from base of the cane giving

rise to profuse/ crowded bunch of tillers bearing narrow leaves which exhibit varying degrees of

loss of cholorophyll, ranging from total green to white (albinism). Cane formation rarely takes place

in affected clumps & if formed they are thin with short internodes giving plant a bushy appearance.

According to reports diseased clumps were observed at average. 6%, 16%,24%, 28%, 24% & 2%

in June, July, August, September, October & November, respectively.

The primary transmission of disease is through infected cane setts while the secondary

transmission is through insect vectors i.e. aphids Rhopalosiphum maidis, Melanaphis sacchari & M

indosachari. Transmission through infected knife & dodder (Cuscuta campestris) may also occur

from diseased to healthy plants.

6. Ratoon Stunting Disease (RSD)

In India the disease was first reported by Prof. Chilton from Gola Gokarannath of

Lakheempur Kheeri distt. of U.P. in 1956 in a cultivar CoS 510. Leifsonia xyli sub sp. xyli a

bacteriaum, is responsible for causing this disease in sugarcane which spreads through diseased

cane setts.

Yellowish leaves, reduced tillering, short internodes & thin stalks are the characteristic symptoms

of RSD. The infected canes when split open longitudinally orange-red vascular bundles in shads of

pink, red & reddish brown or yellow-orange at the nodes can be seen. Well defined symptoms

appear in the crop deficit in moisture, nutrients etc.

7. Leaf- Scaled

This disease is caused by Xanthomonas albileneans and is favoured by wet seasons,

water stress, water logging and low temperature. Symptoms appear in two phases one is “chronic”

and other is “acute”.

In chronic phase “white pencil line” extending in entire length of lamina reaching the margin

of young leaves and stripes diffuse resulting leaf etiolation. Since drying starts tip onwards

therefore a scaled appearence is seen and therefore the name “scaled” has been given, chlorosis

varies from total albinism to interveinal chlorosis in young leaves with bussy appearence in

standing cane if the stalk is cut, then dark colour vascular strands, & prominent streaks al node

may be seen.

In “Acute phase” the symptoms appear suddenly and die without major leaf symptoms. The

masking of symptoms are more common during monsoon and symptoms may appear suddenly

any time during crop growth.

Disease management in Sugarcane

Depending upon mode of survival of the pathogen, its transmission and source of primary

inoculum infection, various diseases occurring in sugarcane, are being managed. For instance.


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Diseases like SCMV & GSD which are primarily transmitted through diseased seed setts &

subsequently aphid vectors play crucial role in transmission of inoculum from a diseased plant to a

healthy plant. The best way to control/ manage the said maladies would be treatment of cane setts

through Moist Hot Air method at 54°C for 4 hours coupled with spray of aphidicides like Methyl-o-

demeton 25 E.C. or Dimethoate 30 E.C. at 0.1 percent concentration for the control of vectors.

Similarly, different aspects of management are taken up for the control of various diseases. When

more than one disease occur together in a crop season or locality the management of each one of

them separately would involve higher cost, more labour & would also consume more time. To over

come with such problems comfortably and effectively use of resistance varieties recommended for

the particular zone followed by the quality and healthy cane seed coupled with due thermotherapy,

chemotherapy and recommended cultural practices are the best way to manage the sett borne

diseases because, sugarcane being a vegetatively propagated crop has a low 1:6 to1:8 seed

multiplication rate and therefore, non-availability of quality seed material is one of the major draw

back faced by the farmers. Further, the bulkey, cane cuttings used for planting as seed harbor

many pest & diseases, thereby decreasing cane yield and quality drastically. Infact poor quality

seed is a major constrant in sugarcane production and disease management as well.

Three tier seed production programme in Sugarcane

As a poor quality seed increases the cost which result in poor germination and

consequently less number of malleable cane & poor production and productivity and more

incidence of disease and pest it is therefore adesible to go for three tier seed production

programme which will not only meet most of the problem but also helpful to minimise the incidence

of the seed borne diseases as mentioned above.

The three tier seed production programme includes the following:

1. Nucleus seed/Breeder seed/ Primary seed: it is genetically 100% pure and free from all kinds

of disease and insect pests. This seed is raised by the breeders of originating centers and used for

foundation seed productions.

2. Foundation seed/ Secondary seed: It is also 100% genetically pure and free from pests and

diseases. It is raised from breeder seed in supervision of Scientist/Breeders. Before planting for

foundation seed, seed material should be treated with hot water or moist hot air. During crop

period five times supervision is required.

3. Certified seed/ Commercial seed: This type of seed is raised without hot water/air treatment.

This type of seed can be raised in farmers plot of the reserve area of the factory or factory farms in

consultation with technician/ technical person. Three inspections or supervisions are required

during crop period in which 100% clumps are examined in first visit and 25% in second and third

visit.

Seed cane standards: There is no certification of seed by any agency so far as sugarcane is

concerned. Recently the seed cane standards for sugarcane have been worked out and the

approved sugarcane seed cane standards for tropical and subtropical India is as under.


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Age of the seed cane at harvest for seed purpose shall be 6-8 months and 8-10 months for

sowing in tropics and subtropical respectively. Buds of seed cane material should be undamaged

and clean. Each node of seed cane shall bear one bud. The number of nodes without sound bud

shall not exceed 5% of total number of buds for seed cane. The number of buds which have

swollen up or have projected beyond one centimeter from the rind surface shall not exceed 5% of

total number of buds.

I. Application and amplification of general seed cane certification standards.

The certified classes shall be produced from the seed canes/or mericlones where sources and

identity be assured and approved by the certification agency.

II. Land requirements

a. A seed crop of sugarcane shall not eligible for certification if planted on land on which

sugarcane was grown in the pervious season.

b. Land/seed crop shall be kept free from sugarcane residues and drainage from other

sugarcane fields.

c. Foundation stage seed should be raised through hot water/ moist hot air treatment

(MHAT).

III. Field inspection:

Seed type Date of inspection after planting (days)

First Second Third Fourth Fifth

Foundation 45-60 120-130

150 250 15 days before harvest

Certified seed or commercial seed

120 200 15 days before harvest

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IV. Field standards:

a. General requirement like isolation.

The sugarcane seed production fields shall be isolated from other fields with a minimum

distance of 5 meters to avoid mechanical mixtures of others varieties

b. At the time of final inspection, tolerance limit of diseases and insect pests should be as

under.

Sl. No.

Disease and insect- pests Affected clumps (%)

Breeder seed

Foundation seed

Certified or commercial seed

1. Red rot, Smut, Wilt, Grassey shoot, Leaf scaled.

0 0 0

2. Scale insects 0 5 5

3. Plassey/Gurdaspur borers 0 0 0

4. Other borers 10 20 20

Important points for quality seed production:

1. All off types and diseased plants shall be rogued out along with roots and destroyed.


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2. Maximum permissible limit for detrashing of dry foliage shall be 2.0%

3. The crop should not have more than 10% lodged canes.

4. Seed cane should not have nodal roots. In waterlogged areas, relaxation may be given

upto a maximum of 5%

5. Moisture in seed cane should not be less than 65% on wet basis.

6. Germinability of buds should not be less than 85%

7. Physical purity of seed should be 98%

8. Genetic purity of seed should be 100%

REFERENCES

1. Agnihotri, V.P. 1990. Diseases of sugarcane and sugarbeet. Oxford & IBH Publishing Co. (P) Ltd., New Delhi.

2. Annonymous, 2009. Souvenir on “Group meeting of AICRP on Sugarcane”. Held at RAU, PUSA (Bihar), Nov. 6-8.

3. Current Trends in Sugarcane Pathology (Prof. K.S. Bhargava Fetscrift). 1994. Eds. G.P. Rao et. al International Books and Periodicals Supply Service, Pitampura. Delhi.

4. Nagarjan, R. 2007. Breeder seed production and slandered, whinter school on sugarcane breedring and genetics in retrospect & prospects, S.B.I, Coimbatore. Oct 3-23, pp 116-118.

5. Rao, G.P.; Singh, Ashutosh; Singh, H.B. and Sharma, S.R., 2005. Phytoplasma Diseases of Sugarcane: Characterization, Diagnosis and Management. Indian J. Plant Pathology. 23(1&2): 1-21.

6. Singh, R.S. 1998. Plant Diseaes (7th ed.) Oxford & IBH Pub. Co. Pvt. Ltd., New Delhi.


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Biolog: Microbial Identification System

R.P. Singh, J. Kumar and Laxmi Rawat Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Biolog microbial identification system (Micro Station ID System) is a versatile system, with

the ability to identify and characterize a wide range of environmental and pathogenic organisms

across diverse fields of microbiology. Using all Biolog databases, over 2650 species of bacteria,

yeast and filamentous fungi can be identified with in few hours. Biolog Microbial Identification

System is based on metabolic phenotypes i.e. the principle that a species of microorganism

develops a unique metabolic finger-print on a set of carbon sources and biochemicals. The

cultured bacteria are tested for utilization of different carbon sources and biochemicals, which are

pre-filled and dried into a 96 well test plate. Cells utilizing nutrient, respire and release energy

which reduces proprietary Tetrazolium dye to form a distinct purple colour. Biolog data collection

software is used to record the unique metabolic profile into the computer which can be compared

with thousands of profiles (corresponding to thousands of species) stored in the Biolog databases.

If the profile is matched, computer displays the identified species. Biolog has designed proprietary

microplates for identification of a wide range of microorganisms up to species level, such as Gen

III plate (for gram negative and gram positive aerobic bacteria), AN plate (for anaerobic bacteria),

YT plate (for yeast) and FF plate (for filamentous fungi).

Just prepare a cell suspension and inoculate the appropriate MicroPlate. After inoculation

and incubation, the MicroPlate is placed into the MicroStation Reader for analysis. The unique

metabolic pattern generated by the organism is recorded and compared to hundreds of

identification profiles in a corresponding Biolog Database. The versatile plate reader uses dual

wavelength readings to quantify color reactions in the MicroPlate wells, adding consistency and

accuracy when reading the reaction patterns. Biolog’s patented redox chemistry makes use of

different carbon compounds including sugars, carboxylic acids, amino acids and peptides to

provide an unparalleled wealth of discriminating biochemical characterizations. This diverse set of

tests enables our systems to identify microorganisms that other kit-based methods misidentify or

fail to identify. The MicroStation System, as well as the OmniLog System, has extensive

applications also for microbial community analysis in soil, water, biofilms and other environments.

Procedure

1. Isolate a pure culture on agar media

2. Prepare inoculum at specified cell density

3. Inoculate the Biolog MicroPlate

4. Incubate the plate, observe and enter the reaction pattern to obtain ID result


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Isolate Prepare Inoculate Incubate & read

Phenotype Micro Array Technology

Phenotype MicroArray technology uses the same chemistry and format, but tests a much

larger and more diverse set of cellular properties. It enables researchers to evaluate nearly 2000

phenotypes of a microbial cell in a single experiment. With automated instrumentation, phenotypic

properties can be measured quantitatively and kinetically, and then recorded automatically into

electronic records. The rough comprehensive and precise quantitation of phenotypes, researchers

are able to obtain an unbiased perspective of the effect on cells of genetic differences,

environmental change, and exposure to drugs and other chemicals. They can correlate genotypes

with phenotypes, determine a cell’s metabolic and chemical sensitivity properties, discover new

targets for antimicrobial compounds, optimize cell lines and culture conditions in bioprocess

development, characterize cell phenotypes for taxonomic or epidemiological studies, and more.

Advantages

Robust and straightway technology

Automated incubation and data collection

Complementary to genomic and proteomic technologies

Rigid or flexible experimental designs are possible

Applications

Cell-line validation and fingerprinting

Understanding metabolism in cells for basic research

Target validation and lead optimization in drug discovery

Inferring mechanism of action of new compounds


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Role of Plant Genetic Resources in Plant Disease Management

R. K. Khulbe Department of Genetics and Plant Breeding, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Plant Genetic Resources (PGR) are the genetic material of plants which are of value for

present and future generations of human kind. Often used as a synonym to plant germplasm PGR

can be defined as seed, a plant or plant part including cell cultures, genes and DNA sequences

that are held in a repository or collected from wild as the case may be and that is useful in crop

breeding, research or conservation because of genetic attributes. PGR have proved immensely

valuable in combating the real and potential threats from the ever-evolving plant pathogens and

will continue to do so in the future as well. The realization of actual importance of PGR in crop

improvement owes much to the massive crop failures such as that caused by southern corn blight

in 1970 that led to renewed efforts at the international level towards ex situ and in situ

conservation of plant genetic resources. PGR have not contributed as much to an area of crop

improvement as disease resistance breeding, be it the incorporation of resistance genes for late

blight in potato or blight and blast in rice or the more recent for stem rust race Ug99 in wheat

In spite of the vastness of germplasm accessions in genebanks world wide (> 7.4 million

accessions), the representation of CWR (Crop Wild Relatives) is only 2-18% (FAO, 2010). Less

than 30 per cent of the accessions are estimated to be distinct. Utilization in crop improvement is

less than 5 per cent. The non-availability of low-cost tools to identity similarities and differences

among the accessions makes elimination of duplicates difficult and the limitation of resources to

extensively evaluate the accessions for various abiotic and biotic stresses restricts their utilization.

For enhancing utilization of variability in genebanks the development of core and minicore

collections has been proposed. A core collection is a subset of accessions from the entire

collection that capture most of the available genetic diversity of the species (Brown, 1989).

Generally, 10% of the crop accessions constitute the core collection representing the variability of

the entire collection. The aim is to reduce the collection to a number manageable for conducting

comprehensive phenotypic and molecular evaluation. The core collection, if large, as in wheat and

rice, may be further narrowed down to mini core collections (Upadhyaya and Ortiz, 2001), which

are 1/100th of the original collection or 1/10th of the core collection, or reference sets of between

300-400 most geographically and genetically diverse genotypes, including those of wild and weedy

relatives. Mini core collections and reference sets are developed by using the qualitative

parameters to develop trait-specific subsets and by characterizing the genetic diversity of each

core sample using molecular markers to reveal the structure of its diversity.Core/mini

core/reference sets of many crops have been developed at various national and international crop

institutes.

Core/minicore collections and reference sets are being increasingly used for assessment of

natural diversity and identification of accessions promising for various traits, for discovering allelic


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variants for important agronomic traits (allele mining) and for establishment of marker-trait

associations (association mapping). Screening/evaluation of these collections have yielded

sources of resistance to black rot in Brassica rapa; eyespot disease in tetraploid wheat; powdery

mildew, scald, leaf rust, net blotch, BYDV and BaMMV in barley; white rust in Brassica oleracea;

leaf rust, powdery mildew and stem rust in wheat; fusarium wilt, dry root rot and botrytis grey mold

in chickpea; and late blight in potato.

Association Mapping

Quantitative trait loci (QTL) for a number of traits in many species have been identified so

far by linkage analysis using populations derived from bi-parental crosses. However, the limited

number of recombination events occurring during the construction of such mapping populations

and the limited number of segregating alleles often result in poor resolution of these QTL. In

addition, the parental genotypes are often not representatives of the germplasm pool that is

actively used in breeding programmes. Hence, there is a substantial time-lag between QTL

discovery and marker assisted crop improvement practices, due to the need to confirm the stability

of the QTL in different genetic backgrounds.

As a new alternative to traditional linkage analysis, association mapping offers three

advantages, (i) increased mapping resolution, (ii) reduced research time, and (iii) greater allele

number (Yu and Buckler, 2006). Association mapping (AM) is a method that exploits the variation

in a collection of genetically diverse materials to uncover a significant association between a trait

and a gene or a molecular marker on the basis of linkage disequilibrium. AM resolves complex trait

variation down to the sequence level by exploiting historical and evolutionary recombination events

at the population level. Association mapping based on PGR collections has yielded some very

valuable marker-trait associations in the recent times. Some of these include markers for glume

blotch and fusarium head blight and spot blotch in barley; stem canker in Brassica napus; stem

rust in wheat; and dieback in lettuce.

Allele Mining

The conventional method of discovering allelic variants for a gene relies upon the

segregation pattern of progeny of two parents supposedly carrying variant alleles. Confounding of

the phenotypic effects and masking effect of stronger alleles severely limit the effectiveness of the

conventional method. Besides, the underlying base sequence variation is not revealed. Allele

mining is a promising approach to dissect naturally occurring allelic variation at candidate genes

controlling key agronomic traits which has potential applications in crop improvement programs

(Kumar et al. 2010). Identification of allelic variants from germplasm collections not only provides

new germplasm for delivering novel alleles to targeted trait improvement but also categorizes the

germplasm entries for their conservation. Allele mining has led to the discovery of numerous allelic

variants for powdery mildew of wheat; stem rust (Ug99) of wheat; leaf blast of rice; late blight of

potato; and many other important diseases in various crops.


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Pre-breeding

Pre-breeding is the preliminary phase in plant breeding that involves transfer of genes for

desirable traits from agronomically unadpted backgrounds to adapted genetic backgrounds to

facilitate utilization of such genes in crop improvement programmes. Pre-breeding makes use of

conventional plant breeding procedures such as back-crossing and pedigree methods. The advent

of Marker-Aided-Selection (MAS) procedures has greatly facilitated pre-breeding. In pre-breeding,

alternative approaches such as somatic hybridization, bridge species and irradiations etc., also are

used for introgression of desirable genes from sexually incompatible species. The most recent

examples of pre-breeding include transfer of stem rust (Ug99) resistance into cultivated wheat

from its diploid, tetraploid and wild relatives.

Future thrusts

The utilization of PGR in plant disease management may be enhanced by augmenting

diversity and reduction in size of genebank collections and development of core/minicore

collections and disease-specific ‘reference sets’ to enable comprehensive evaluation of the

accessions. Special thrust needs to be laid on collection, conservation, evaluation and utilization of

CWR (Crop Wild Resources), which are reservoirs of disease-resistance genes. The utilization

may be further enhanced by developing low-cost molecular tools for discovery of new genes and

alleles for disease resistance, which could be used to develop cultivars with broad-based disease

resistance using molecular marker-aided breeding procedures.

REFERENCES

1. Brown AHD. 1989b. Core collections: a practical approach to genetic resources management. Genome 31: 818-824.

2. FAO 2010. The Second Report on the State of the World’s Plant Genetic Resources for Food and Agriculture. Rome

3. Kumar GR et al. (2010) Allele mining in crops: prospects and potentials. Biotechnol. Adv. 28, 451–461

4. Upadhyaya HD and Oritz R. 2001. A mini core subset for capturing diversity and promoting utilization of chickpea genetic resources in crop improvement. Theor. Appl. Genet. 102:1292–98.

5. Yu J and Buckler Iv ES. 2006. Genetic association mapping and genome organization of maize. Current Opinion in Biotechnology 17:155-160


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Disease Management under Protected Cultivation

R. P. Singh and Mamta Mathpal Department of Plant Pathology, GBPUA&T, Pantnagar- 263 145 (Uttarakhand)

Protected cultivation is a cropping technique in which the micro climate, surrounding the

plants is controlled partially or fully as per the requirement of the plant species grown, during their

period of growth. With the advancement in agriculture various types of protected cultivation

practices suitable for a specific type of agro-climatic zone have emerged. Among these green

house, glass/poly house, Trench Planting, Low tunnel, High tunnel and Rain shelter are common

techniques. Under controlled environment crops could be grown under the inclement climatic

conditions when it would not be otherwise possible to grow crops under the open field conditions.

The crop yields are at the maximum level per unit area, per unit volume and per unit input basis

with high quality produce which could fetch the export markets. It can not only be used to generate

self employment for the educated rural youth in the farm sector, but income from the small and the

marginal land holdings can also increased by growing off season crops.

Though greenhouse technology is more than 200 years old, but in India, the technology is

still in its infancy stage. The area under green house cultivation as reported to be about 500 ha in

India. This figure is quite non significant when compared with the total area under green house in

the world, but the face is changing and trend is encouraging. Now a day, much needed vegetables

are being grown throughout the year in these hostile climates. Production of brinjal, capsicum,

tomato and other cucurbits is taken in the summer months on a large scale, whereas the green

leafy vegetables are being grown in the long frozen winter months when the average temperature

reaches- 30.20C. Underground greenhouses and soil trenches are also being used on a large

scale in these remote areas. Ornamental crops like gerbera, carnation and roses are being grown

for cut flowers under poly houses on large scale. Farmers are also utilizing low and medium cost

greenhouses for raising potted plants and seedlings in the nursery. In the Northern Gangetic plains

the farmers are using this technology to raise healthy seedlings of high yielding crop varieties so

that they can be transplanted early in the fields during the onset of the spring season so as to

capture the early markets and thus reap higher returns. There is a vast scope for expansion of

green house technology in India.

The incidence of pest problem under protected conditions is higher than in the open. The

green house climate is ideal for the development of plant diseases. While creating favorable

environment in the greenhouse for growing high value crops; we also create a favorable habitat for

their insect, pests and diseases. Under greenhouse conditions, natural forces which keep pest

population below threshold level are under controlled. Direct sun, ultraviolet light, and the constant

changes in temperature also play an important role in overall natural pest control often obtained

under open conditions. The greenhouse literally protects its plants and consequently their

respective pests from these environmental conditions. High day time temperatures and relative


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humidity, poor ventilation and plant hygienic condition provide ideal conditions for the introduction

and rapid multiplication of insects, as well as fungal, bacterial and viral pathogens. Inadequate soil

disinfection and absence of adequate fallow and rotations also provide ideal conditions for the

multiplication of soil borne plant pathogens. Due to high value of crops under such conditions, an

economic threshold level of most insects and disease problem are lower and requires more

monitoring and care. Right from nursery raising and seedling plantations to harvesting, crop need

very well planned disease and pest management strategies.

The planning for the protected cultivation system should include Greenhouse construction

design (especially height, heating, insect screens, and ventilation components), an irrigation

system that minimizes leaf wetness and humidity at the plant canopy level, selection of available

pest resistant varieties, pest-free and healthy transplants that minimize introduction of plant

pathogens, nematodes, and insects. Apart from this, optimum fertilizer programs that result in

healthy growth as opposed to maximum growth, scouting for diseases, nematodes and insects

during the growing season, sanitation practices that minimize microorganism movement from

diseased plants to healthy ones, including removal of all plant materials after final harvest, and

shipping practices. Such practices maximize product quality and application of such integrated

practices will ensure good quality and environmentally safe products to the consumers at the same

time, enhancing economic returns to the growers.

Disease management in poly houses may have two approaches: 1) those aimed at the root

environment, and 2) those aimed at the aerial environment.

Management of Root Environment :

Soil disinfection is an important part of control of soil-borne plant pathogens when raising

vegetables by the ground culture method or when soil-based potting mixes are used. Soil-borne

diseases include damping-off (Pythium and Rhizoctonia), root rots (Sclerotinia), and wilts caused

by Fusarium and Phytophthera. Potting mixes based on compost, peat moss, vermiculite, perlite,

and bark are typically pathogen-free and do not require prior sterilization.

Chemical biocides, electrical heat, steam heat, and soil solarization are the primary methods of

soil disinfection in greenhouse production. Another method of disease suppression is biological

control. Soil fumigation with formaldehyde is also practiced, of course, restricted in organic

production. Steam pasteurization and soil solarization are the two most viable options for sterilizing

greenhouse soils or large volumes of soil-based mixes. Biological control is complementary to

these two methods.

Management of Aerial Environment

Foliar and stem diseases include gray mold (Botrytis), powdery mildew (Erysiphe spp.),

early blight (Alternaria spp.), soft rot (Erwinia spp.), and several other fungal and viral diseases

caused by Xanthomonas, Fusarium, and Psuedomonas.

Greenhouse climates are warm, humid, and wind-free-an ideal environment for the development of

many foliar and stem diseases. For the majority of pathogenic fungi and bacteria, infection usually


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occurs when a film or drop of water on the plant surface persists. Unless temperature, humidity,

and ventilation are well regulated, this surface water can remain in the greenhouse until infection

becomes assured.

Integrated disease management, therefore, is based on climate control for disease

infection and optimum crop yield and quality. It eliminates inoculum through high standards of

hygiene (sterilizing soil or using soilless media, obtaining disease-free planting material, chlorine

bleach rinses of footwear & equipment, vegetative-free floors, etc.), cultural practices for limiting

disease spread, biological and pesticidal control, and, most important, is use of resistant varieties.

Management of Environment:

Temperature and humidity regulation, ventilation, vapor pressure, and structure-are

increasingly becoming computerized. Expert software that reduces disease-infective conditions

while promoting crop growth is available in the developed countries but its use in India is still very

limited.

Points to be considered during pest management programme:

The planning stage for the production system should include the following considerations:

a. Greenhouse construction design (especially height, insect screens, and ventilation

components) and an irrigation system that minimizes leaf wetness and humidity.

b. Use of available resistant varieties

c. Healthy and disease free transplants that minimize introduction of plant pathogens and

nematodes.

d. Optimum fertilizer programs that result in healthy growth.

e. Scouting for diseases, nematodes and insects pests incidence during the growing season.

f. Sanitation practices that minimize movement of inoculums from diseased plants to healthy

ones, including removal of plant residues after harvest.

g. Harvesting, packaging and transportation practices that maximize produce quality.

Problems in disease management under protected cultivaton:

1. Lack of available chemical control measures for the greenhouse:

2. Problem of frequent harvests over a long period of time:

3. Non availability of equipments to apply pesticides efficiently:

Conclusion

An integration of cultural practices, environmental control and natural control products is

required to manage insect pests and diseases under green house conditions and to prevent wide

spread outbreak. Integrated practices can only ensure economically and environmentally

acceptable greenhouse crops to the society.


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Engineering Resistance against Biotic Stress Affecting Horticultural and Field Crop

N.K. Singh

Department of Genetics and Plant Breeding, GBPUA&T, Pantnagar- 263 145 (Uttarkhand)

The crop yield decline due to pathogens and pets is still substantial despite of availability

and use of sophisticated and intensive crop-protection measures. Varieties bred using the

classical approach of Genetics and Plant Breeding have been used alone or in combination with

chemical or biological control measures to minimize the loss incurred due to biotic factors.

Molecular breeding has been added as another tool to manipulate the resistance gene (s).

However, classical and molecular breeding approaches rely on vertical variability only.

Advancement in science, more specifically in the areas of Molecular Biology and Genetic

Engineering, has enabled scientists to exploit horizontal variability for engineering tolerance to

biotic factors. Commercialization of Bt gene based crops is an excellent example of engineering

plants using horizontal variability. Over the past two decades, crops with intrinsic pest and

pathogen resistance have been developed using genetic transformation. Plants transformed with

insect-control-protein genes are resistant to insect pests, and new proteins from any genera or

species with novel modes of action will further provide broad spectrum resistance to pests.

Resistance to a range of fungal and bacterial pathogens has been conferred by expression of a

variety of genes, and viral-pathogen-derived genes have been used to produce crops immune to

viral infections. These advances form the basis of a ‘environmentally sound’ and economically

viable approach to pest and disease control in field as well as horticultural crops.

Insect pests and diseases caused by fungal, viral and bacterial pathogens are responsible

for substantial losses in crop yields worldwide. Thus, one of the challenges confronting scientists

worldwide is to develop new and sustainable ways of protecting crops from pests and diseases.

Controlling biotic stress and producing crops with special agronomic traits is therefore of

paramount importance for reducing the threat to crop productivity, farmers’ net income, the food

supply, and by extension, the economies of rural areas.

To combat losses caused by biotic stress, various crop husbandry techniques have been

adopted, and the most widely used management strategy is the application of agrochemicals.

However, chemical protection against bacterial pathogens has not evolved as quickly as that

against fungi, and is not applicable to viruses. The intensive use of agrochemicals has led to the

development of resistance in various pest and pathogen populations and in some cases the

chemicals are no longer used because of their high toxicity to non-target species. Nowadays, the

focus is on strategies that allow for crop production with minimal use of agrochemicals and the

most effective strategy involves breeding resistant crop cultivars. However, there are many

pathogens for which no effective sources of disease resistance have been identified.

Although enhanced resistance has been introduced into crops by traditional plant breeding


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programs with some success, effective resistance against several destructive insect pests and

pathogens is still lacking. This is evident in the commercial use of a large number of chemical, and

few biological, pesticides for crop protection. However, effective and durable resistance genes to

control many viral and bacterial diseases have not been identified in plants, and there is a need for

new sources of resistance in many crops. Recently molecular breeding approach has resulted in

transfer as well pyramiding of genes in many crop plants. In wheat, the leaf rust resistance genes

Lr24 and Lr28 were the first two genes pyramided through MAS in India in 2003-04 in the variety

HD 2329, which has been followed up with PBW 343 pyramided with the same two genes at IARI,

New Delhi. Now there are large number of combinations in different trials having components of

Lr24, Lr28, Lr9, Lr19 and adult plant resistance genes like Lr48. The genes Lr24, Lr28 and Lr9,

Lr37 have been pyramided in the genetic background of popular cultivar WH147 in various

combinations using validated molecular markers for these genes. Pyramided lines with gene

combinations Lr24+Lr28,Lr24+Lr37,Lr28+Lr37 in the genetic background of WH147 and gene

combinations Lr24+Lr28+Yr15 in the background of high yielding cultivar HD2687 have been

produced using molecular markers. In rice, MAS has been successfully exploited for pyramiding

different genes for bacterial leaf blight and blast diseases. ‘Pusa 1460’, is a new version of ‘Pusa

Basmati 1’ developed by Indian Agricultural Research Institute. This variety developed by

pyramiding bacterial leaf blight (BLB) resistance genes (xa13 & Xa21) in the background of ‘Pusa

Basmati 1’ through marker assisted backcross breeding. Similarly another variety namely ‘RP BIO

226’ developed by Directorate of Rice Research using MAS. ‘RP BIO 226’ is developed by marker

assisted pyramiding of three BLB resistance genes (Xa21, xa13 and xa5) in the genetic

background of an elite fine grained rice variety, Samba Mahsuri. Two high yielding BLB

susceptible indica rice cultivars ADT43 and ASD16, popular among farmers and consumers

across South India were introgressed with the three BLB resistance genes xa5, xa13 and Xa21

using functional markers. Thirty pyramided genotypes with two or three resistance genes

exhibited high levels of resistance against two predominant Xanthomonas oryzae isolates of South

India. Twelve pyramided genotypes (xa5 + xa13 + Xa21) were found to be significantly high

yielding with desirable agronomic characteristics and the selection efficiency of the present

markers was hundred percent. Three rice blast resistance genes, namely Pi1, Piz5 and Pita have

been pyramided in a susceptible rice variety, CO39 using RFLP and PCR-based markers for

durable blast resistance.

Genetic engineering or recombinant DNA technology, together with plant transformation

and tissue culture techniques, has facilitated the precise manipulation of desirable gene (s)

bypassing the cross incompatibility barrier and development of transgenic plant cultivars with

enhanced arthropod pest and disease resistance. In contrast to conventional breeding, which

involves the random mixing of tens of thousands of genes present in both the resistant and

susceptible plant, recombinant DNA technology allows the transfer of only the resistance gene to

the susceptible plant and the preservation of valuable economic traits. Moreover, the genetic


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sources for disease resistance are not limited to closely related plant species. Genetic engineering

work requires a gene to be transferred, systems to transfer gene in plant parts and a well

established regeneration system so that transformed cell/tissue could be regenerated into whole

plant. There are different approaches used for transfer of gene. These approaches are based on

Agrobacterium-a plant pathogenic agent, Liposome encapsulation, Electroporation, Microinjection,

DNA injection into intact plants, Incubation of seeds with DNA, Pollen tube pathway, Laser

microbeam, Silicon carbide fibre and Particle bombardment. However, Agrobacterium and particle

bombardment or gene gun mediated gene transfer approach has been most successful in transfer

and stable integration of gene in most of the plant species and all the transgenic plants are

transformed using either Agrobacterium or particle bombardment approach.

The first genetically engineered tomato plant (FlavrSavr TM) engineered for delayed

ripening was released for commercial cultivation in 1994. Since then, many crops have been

introgressed with various gene (s) from different sources and adopted for cultivation across the

Continents. The present area under the genetically engineered crops are 148 m ha where the pre-

dominant crop is soybean followed maize, cotton and canola, and the pre-dominant trait is

herbicide tolerance followed by herbicide+ insect tolerance and insect tolerance. Several crop

varieties with agronomically useful levels of resistance to insects and viral pathogens have been

generated through gene transfer, and these are rapidly moving towards commercialization.

The engineering of crops for insect tolerance has been moved quite ahead probably

because of necessity as well as availability of efficient genetic system (e.g. Bt gene). In addition to

Bt gene, many other genes from different sources such as cholesterol oxidase, lectin, β-

glucosidase gene, proteinase inhibitor, amylase inhibitors, vegetative insecticidal proteins etc have

also been used for insect tolerance. In India, cotton is the only crop where genetically engineered

crop is grown. Cotton varieties engineered with cry1Ac gene (Bollgard-I : MECH 12 Bt , MECH 162

Bt and MECH 184 Bt) was permitted first time for commercial cultivation in the year 2002.

Bollgard II technology was introduced in 2006 where two transgenes namely Cry1Ac gene and

Cry2Ab gene were stacked together to provide better control of three types of bollworms along

with Spodoptera and army worm.

The genetic engineering of virus-resistant plants has exploited new genes derived from

viruses themselves in a concept referred to as ‘pathogen-derived resistance’ (PDR). The first

transgenic tobacco plants with increased resistance to tobacco mosaic virus (TMV) resulted from

the expression of a coat protein (CP) gene. This resistance was referred to as coat-protein-

mediated resistance (CP-MR). CP-MR has been found to be effective against almost all classes

of viruses in many different plants, including melon, rice, papaya, potato and sugar beet. As was

the case for CP-MR control of TMV, plants showed resistance to the virus from which the gene for

the CP was derived, but not to other unrelated viruses. A post-transcriptional mechanism involving

homology-dependent gene silencing has been deployed in development of a variety of yellow

squash, called Freedom II. Potatoes expressing U-length PVY or potato leafroll virus (PLRV)


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replicase genes are highly resistant to all strains and isolates that have been tested so far. It has

been proposed that the replicase-mediated resistance to PVX may be due to an RNA-based

mechanism that depends on homology-dependent gene silencing. A durable and broad-spectrum

resistance to viral pathogens may be engineered through a combination of PDR strategies in

transgenic plants, or through the combination of genetically engineered resistance with resistance

achieved through classical plant breeding.

The development of transgenic crops that are resistant to fungal diseases has lagged

behind that of virus- and insect-resistant varieties. A few examples of transgenic plants exhibiting

high levels of resistance to fungal pathogens however showed prospects for engineering tolerance

to fungal diseases. Moreover, several new advances in the field further showed an optimistic

outlook for the development of fungus-resistant crops. First, several antifungal proteins with strong

in vitro antifungal activity have been identified and cloned. Second, the long awaited cloning of

fungal-disease resistance genes has now been accomplished. Third, there has been an enormous

increase in our understanding of the molecular events underlying plant-pathogen interactions,

which will hopefully aid our attempts to develop agronomically useful and durable resistance to

fungal pathogens in transgenic crops. Strategies for the production of fungus resistant transgenics

can be basically classified into two categories namely (i) production of transgenic plants with

antifungal molecules like proteins and toxins, and (ii) generation of a hypersensitive response

through R genes or by manipulating genes of the SAR pathway.

Progress in the development of bacterial-pathogen resistant crops has also lagged behind

that in the development of insect- and virus-resistant crops. However, advances in the cloning of

several new bacterial-resistance genes, such as the Arabidopsis Rps2 gene and the tomato Pto

gene, may provide insights into our understanding of plant-bacterial interactions at the molecular

level. Attempts to express antibacterial magainins or cecropins in plants for bacterial resistance

have met with little success. Some success was observed with a bacteriophage T4 lysozyme. The

expression of a bacteriophage T4 lysozyme in transgenie potato tubers led to increased resistance

to Enviniu curotovora subsp. atroseptica. The plant proteins, thionins, often display toxicity in vitro

to plant pathogens. The expression of a barley a-thionin gene significantly enhanced the

resistance of transgenic tobacco to the bacterial pathogens Pseudomonas syringae pv. tabaci.

Nonhost specific toxins are the major virulence determinants of bacterial pathogens, in particular

the pathovars of Pseudomonas syringae. Expressing a toxin inactivating enzyme has been

successfully used to engineer resistance to a bacterial pathogen. The expression of a toxin-

resistant OCTase gene in transgenic tobacco and bean plants led to agronomically useful levels of

resistance to the bacterial pathogen; evidence for this was the induction of a hypersensitive

response (HR) to infection by P. syringae pv. pkaseolicola.

Genetic engineering of crops will be a valuable option to increase and stabilize yields in a

world with a changing climate and a growing human population. It will also help in minimizing the

chemical pollutions in environment. However, GE tools must not be used in isolation rather it


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should be integrated with classical as well as molecular plant breeding to address the problems of

biotic stresses and stabilize the crop yield in eco-friendly manner. A few virus resistant and many

insect resistant GM cultivars have been on the market for more than a decade and their number

are likely to expand in the future. However, for the economically far more important fungal

diseases, more fundamental research, particularly for potential resistance mechanisms and their

durability, is still needed. Specifically, an important move would be to exploit the potential and

proven durability of natural resistance through introgression between species. In addition, the

major challenge remains in molding public opinion on the potential on the potential of diseases

resistant GM crops to reduce the need for pesticides. Despite these precautions, GM crops have

already contributed significantly in world agriculture and we strongly believe that disease resistant

crops have a role to play in future strategies for plant disease control.

VALEDICTORY ADDRESS by

Vice-Chancellor


on

April 11, 2011

It is a pleasure having to deliver the

valedictory address on the successful completion of

the 24th

CAFT training on “Climate change,

Precision agriculture and innovative disease control

strategies”. I am sure that you all have enjoyed the

scientific interaction during your stay at Pantnagar

as well as exposure trip to Ranichauri during course

of the training.

You may be aware that the world’s

population is anticipated to increase from 5.7 billion

in 1995 to 7.7 billion in 2020 with 80 per cent of the

population living in developing countries, where the

population increases by 1.9 per cent per year. Most

poor people live in areas where the land is marginal

and ecosystems are fragile. Global food production

is 5 billion tons per annum and at least 10 per cent

of global food production is lost to plant disease.

Plant pathologists cannot ignore the juxtaposition of

these figures for food shortage and the damage to

food production caused by plant pathogens.

To feed the ever growing population and

ensuring food security, the Green Revolution model

of agriculture though successfully ensured the food

security, yet there are a host of environmental and

health consequences, widely documented, and

which have implications for food consumption and

nutrition. From the pathologist’s point of view, the

most critical effect of the Green Revolution has

been the increased use of pesticides and chemical

fertilizers. As a result lots of negative effects

occurred including land degradation and genetic

erosion, which resulted in explosive growth of pests

and diseases in the crops.

Although plant breeders continue to breed high-

yielding varieties most of which have been grown

under irrigation conditions. With the addition of

fertilizer and under monocropping, ideal

environment is created for pest and weed growth.

Data suggest that pesticide use rose to over half a

billion tons in the developing world by the 1980s,

accounting for 1/5th of global production, with a

much higher rate of insecticides, which are more

toxic to humans and other organisms. In addition to

the obvious human health implications, excessive

pesticide use increases pest outbreaks by

increasing resistance to pest populations while

eliminating natural pest predators. All of these

effects have implications for food consumption and

nutrition, through complex and inter-related

pathways.

The impact of pests, diseases and weeds

on food supply is as high that they reduce

production by at least one-third, and that diseases

alone reduce production by more than 10 per cent

despite the use of pesticides worth $32 billion.

History illustrates that plant diseases can have a

significant effect on human society.

Chemical pesticides have reduced crop

losses in many situations, but even with a very

substantial increase in pesticide use, the overall

proportion of crop losses and the absolute value of

these losses from pests appear to have increased

over time. Despite this perverse relationship, a

marginal increase in pesticide use still appears to be

profitable.

Keeping in view these facts about the use

and misuse of pesticides and its long lasting effects

on agriculture, newer technological approaches to

improving pest management that do not necessarily

depend on chemical pesticides have come forward.

i

These include plant breeding, the use of biological

control agents, and biotechnology, although

elements of all these technologies are often used

together frequently with chemical pesticides.

There is clear evidence that climate change

is altering the distribution, incidence and intensity of

plant pests and diseases such as those pests

whose distribution is shifting most likely due to

climatic factors. Plant pests and diseases are not

evenly distributed over the globe, often because

they are limited by physical barriers such as

mountains, seas and deserts. The increase in

movement of people, animals, plants, goods and

conveyances has accelerated the redistribution of

plant pests and diseases and climate change will

create new ecological niches allowing for the

establishment and spread of pests and diseases

into new geographical areas and from one region to

another.

In addition, unforeseen emergence of “new”

diseases and pests has been very common.

Change in climate resulting in changes in species

composition and interactions will augment the

emergence of unexpected events, including the

emergence of new diseases and pests.

Overall climate change will result in a higher

volatility and, therefore, is likely to cause additional

crises in local agricultural production with different

consequences for socio-economic groups and

genders. Plant pests/pathogens and changes in

pest/pathogens incidence and intensity may result

in additional and inappropriate pesticide use.

Changes in rainfall, temperature and relative

humidity may favour the growth of fungi that

produce mycotoxins and thus may make food such

as groundnuts, wheat, maize, rice and coffee

unsuitable for human and animal consumption.

Plant pathologists can help identify disease

problems and help disseminate information to both

private and government organizations for use in

education and in planning actions to reduce world

hunger. Plant pathologists can also help maximize

agricultural production by assisting in crop

improvements, reducing input requirements, and

through better assessment of disease problems.

Long term solutions may be found through

sustainable agriculture and integrated pest

management (IPM). By combining knowledge and

resources, plant pathologists can work together

toward increasing food security and reducing world

hunger. The new technologies, through appropriate

policies, can be made accessible to small-scale

farmers. Instead of rejecting the solutions offered by

science, policies may be changed to ensure that the

solutions benefit the poor. A good approach would

be to integrate all the advances made in genetics,

agronomy, pathology, technology, economy and

sociology into a single system. Improved diagnosis

of diseases and pests, as well as of water, soil and

air quality remains another research challenge

because a lot of time and money is lost on

identifying the problems. One of the important ways

of enhancing food security is to support small scale

farming. It will not only increase agricultural

productivity, but will also help small farmers out of

poverty, as they could sell over-production and

reinvest gains in diversifying their production.

I am delighted to know that all such points

were appropriately addressed in this particular

training course, which I am sure was very well

designed and appropriately conducted.

It is hoped that you would use the

knowledge gained through the training in teaching,

research and extension activities at your respective

institution/university. You are now in a way alumini

of this university and I am sure that you will maintain

this linkage in a dynamic manner for our mutual

benefit in the pursuance of science of Plant

Pathology, especially in the area of plant health

management.

I wish you a safe and comfortable journey

back home and fruitful professional career ahead.

Jai Hind

ii

ANNEXURE-I

CENTRE OF ADVANCED FACULTY TRAINING IN PLANT PATHOLOGY

College of Agriculture, Pantnagar-263 145 (Uttarakhand)

Following committees have been constituted for smooth conduct of the training programme

on “Climate change, precision agriculture and innovative disease control strategies”

scheduled on March 23 to April 12, 2011.

1. Overall Supervision

Dr. J. Kumar, Director CAFTPP

Dr. R.P. Singh, Course Coordinator

Dr. H.S. Tripathi

Dr. R.P. Awasthi

Dr. V.S. Pundhir

Dr. (Mrs.) K. Vishunavat

2. Invitation, Inaugural and Closing Function Committee

Dr. H.S. Tripathi– Chairman

Mr. Narender Singh

Mr. S.P. Yadav

Mr. Mani Ram

3. Inaugural Session, Intersession Tea and valedictory function Committee

Dr. K.P.S. Kushwaha – Chairman

Dr. (Mrs.) Deepshikha

Mr. S. P. Yadav

Mr. Jagannath

4. Budget Committee

Dr. R. P. Awasthi – Chairman

Dr. Yogendra Singh

Mr. K. S. Bhatnagar (Account Officer)

Mr. A. B. Joshi

Mr. Praveen Kumar

Mr. Het Ram

5. Transport and Reception Committee

Dr. Pradeep Kumar – Chairman

Mr. Prakash Joshi

Mr. P.C. Khulbe

Mr. Bhupesh Kabadwal

6. Boarding & Loading Committee

Dr. V.S. Pundhir – Chairman

Dr. R.K. Bansal

Mr. S. P. Yadav

7. Registration Committee

Dr. (Mrs) K. Vishunavat – Chairperson

Dr. (Mrs.) Kanak Srivastava

Dr. (Mrs.) Renu Singh

8. Session Arrangement Committee

Dr. S.C. Saxean – Chairman

Dr. A.K. Tewari

Mr. Prakash Joshi

Mr. Vikram Prasad

9. Field / Excursion Trip Committee

Dr. R.K. Sahu – Chairman

Dr. Vishwanath

Mr. M.K. Sharma

Mr. K. S. Bisht

Mr. R. B. Sachan

10. Audiovisual Aid & Publicity Committee

Dr. A.K. Tewari-Chairman

Mr. R.C. Singh

Mr. Bupesh Kabdwal

11. Committee for typing correspondence work

Dr. K.S. Dubey, Chairman

Smt. Meena Singh

Mr. Rakesh Tewari

Mr. Mehboob

i

ANNEXURE-II

LIST OF PARTICIPANTS

Sl. No.

Name and Address Phone/E-mail

1. Shri. D.B. Patel

Assistant Research Scientist

Department of Plant Pathology

Centre of Excellence for Res. on Pulses

S.D. Agricultural University

Sardarkrushinagar- 385 506 (Gujarat)

(O): 02748-278158 (Mb.): 9913721465 E-mail: [email protected]

2. Dr. Rajesh Chandra Verma

Asstt. Prof./SMS (Plant Protection)

Krishi Vigyan Kendra, Hastinapur

(SVPUAT, Modipuram)

Hastinapur- 250 404 (U.P.)


3. Dr. Rudra Pratap Singh

SMS-Plant Protection

Krishi Vigyan Kendra

N.D. Univ. of Agric. & Tech, Faizabad

Kotwa, Azamgarh- 276 001 (U.P.)

(O): 0546-2243179 (R): 0546-1226428 (Mb.): 09415720507 E-mail: [email protected] [email protected]

4. Dr. Virendra Singh

SMS/Asstt. Prof. (Plant Protection)

SVPUA&T, KVK, Cotton Research Farm

, Bulandshahr- 203 001 (UP)

(O): 05732-223103 (R): 09456841516 (Mb.): 09411477003 E-mail: [email protected]

5. Dr. Chet Ram Prajapati

SMS/Assistant Professor

Deptt. of Pl. Protection

K.V.K., Khekra, Baghpat- 250 609 (UP)

(Mb.): 09450129403 E-mail: [email protected]

6. Shri. Ram Kumar Singh

Asstt. Professor

NARP-Daleepnagar, Directorate of A.E.S.

C.S.A. Univ. of Agric. & Tech.

Kanpur- 208 002 (U.P.)

(O): 0512-2534128 (R): 0512-2583343 (Mb.): 09450174634 E-mail: [email protected]

7. Dr. Mehraj-Ul-Din Shah

Assistant Professor-cum-Jr. Scientist

Division of Plant Pathology

SKUAST- Kashmir

Shalimar, Srinagar- 191 121 (J&K)

(Mb.): 09419088345 (R): 0194-2106305 E-mail: [email protected] [email protected]

i

8. Dr. (Mrs.) Magar Sunita Janardhanrao

Assistant Professor


College of Agriculture, Latur

Marathwada Agricultural University

Parbhani (MS)


9. Shri. S.S. Karande

Associate Professor & I/C Principal

Lokmangal Agriculture College

A/P-Wadala, Tal-N. Solapur

Distt. Solapur- 413 222 (M.S.)

(O): 0217-2735521 9923404691 9860704554 E-mail: [email protected]

10. Dr. S.D. Somwanshi

Assistant Professor


College of Agriculture, Udgir

Marathwada Agril. University

Parbhani (MS)


11. Dr. (Ms.) Shiwani Bhatnagar

Assistant Professor (Agriculture)

Deptt. of Education in Sci. and Mathematics

Regional Institute of Education (NCERT)

Shyamla Hills, Bhopal- 462 013 (M.P.)


12. Dr. Ashish Kumar Tripathi

SMS (Plant Pathology)

Krishi Vigyan Kendra (JNKVV)

Nowgong, Chhatarpur- 471 201 (M.P.)


13. Shri. Moti Singh Rathore

SMS (Agronomy)

Vidya Bhawan Krishi Vigyan Kendra

Badgaon, Udaipur- 313 011 (Rajasthan)


14. Mrs. Poly Saha

Assistant Professor (Plant Pathology)

Orissa University of Agric. & Tech.

Bhubaneswar-3 (Orissa)

(O): 06753-211210 (R): 08895173687 (Mb.): 08895173677 E-mail: [email protected]

15. Dr. Rupesh Kumar Arora

SMS (Plant Protection)

Krishi Vigyan Kendra, Tepla

Ambala- 133 104 (Haryana)


ii

16. Dr. Tejbir Singh

SMS/Asstt Prof. (Plant Protection)

Krishi Vigyan Kendra

Jeolikote, Nainital- 263 127 (UK)


17. Dr. (Mrs.) Shailbala

Jr. Research Officer (Plant Pathology)

Sugarcane Research Centre

Kashipur- 244 713 (UK)

(O): 05947262281 (Mb.): 9456678706 E-mail: [email protected]

18. Dr. (Mrs.) Gohar Taj

Assistant Professor,Department of MBGE

College of Basic Sciences & Humanities

GBPUA&T, Pantnagar- 263 145 (UK)


19. Dr. (Mrs.) Nirmala Bhatt

SMS/Asstt. Professor (Plant Protection)

Krishi Vigyan Kendra, Gaina-Aincholi

Pithoragarh- 262 530 (Uttarakhand)

(O): 05964 -252175 (R): 05964-264006 (Mb.) 9412044788 E-mail: [email protected]

20. Dr. Dharmendra Singh Rawat

Assistant Professor

Department of Biological Science

College of Basic Sciences & Humanities

GBPUA&T, Pantnagar- 263 145 (UK)


S U M M A R Y

Sl. No. State No. of participants

1 Gujarat 01

2 Haryana 01

3 Jammu & Kashmir 01

4 Madhya Pradesh 02

5 Maharashtra 03

6 Orissa 01

7 Rajasthan 01

8 Uttara Pradesh 05

9 Uttarakhand 05

Total Participants 20

iii

ANNEXURE-III

TRAINING

ON

CLIMATE CHANGE, PRECISION AGRICULTURE AND INNOVATIVE DISEASE CONTROL STRATEGIES

(March 23 to April 12, 2011)

Venue Committee Room, Department of Plant Pathology

Sponsored by Centre of Advance Faculty Training in Plant Pathology (ICAR, New Delhi)

GUEST SPEAKERS/CONTRIBUTORS Dr. Rakesh Pandey Scientist, Central Institute of Medicinal &Aromatic Plants

(CIMAP), Near Kukrail Picnic Spot, Lucknow (UP)

Dr. D.K. Chakrabarty Professor Plant Pathology, Department of Horticulture, NDUAT, Kumarganj, Faizabad (UP)

Dr. S.L. Chaudhary Asian Agri-History Foundation Rajasthan Chapter , Udaipur (Rajasthan)

Dr. Rupam Kapoor Associate Professor, Department of Botany, University of Delhi, New Delhi

Dr K. S. Hooda Principal Scientist, Plant Pathology, Directorate of Maize, Research, Pusa Campus, New Delhi

Dr. Y.P. Singh Principal Scientist, Forest Pathology Division, Forest Research Institute, Dehradun

LOCAL SPEAKERS

Dr. S.K. Saini Dean, College of Agriculture

Dr. M.C. Nautiyal Dean, Hill Campus Ranichauri

Dr. J. Kumar Professor and Head-cum-Director CAFT Plant Pathology

Dr. S.C. Saxena Honorary Professor, Plant Pathology

Dr. K.P. Singh Emeritus Scientist, Plant Pathology

Dr. H.S. Tripathi Professor, Plant Pathology

Dr. R.P. Awasthi Professor, Plant Pathology

Dr. (Mrs.) K. Vishunavat Professor, Plant Pathology

Dr. V.S. Pundhir Professor, Plant Pathology

Dr. R.K. Sahu Professor, Plant Pathology

Dr. Vishwanath Assoc. Prof., Plant Pathology

Dr. R.P. Singh Assoc. Prof., Plant Pathology

Dr. K.P.S. Kushwaha SRO, Plant Pathology

Dr. Y. Singh SRO, Plant Pathology

Dr. A.K. Tewari SRO, Plant Pathology

Dr. N.W. Zaidi SMS, Plant Pathology

i

Dr. S.N. Tewari Professor, Entomology

Dr. Ruchira Tewari Assistant Professor, Entomology

Dr. H.S. Kushwaha Professor, Soil Science

Dr. A.K. Agnihotri Professor, Soil Science

Dr. K.P. Raverkar Assoc. Professor, Soil Science

Dr. P.C. Srivastava Professor, Soil Science

Dr. Rajeev Kumar Shukla Asstt. Professor, Agronomy

Dr. H.S. Chawla Prof. & Head, Genetics and Plant Breeding

Dr. D. Roy Professor, Genetics and Plant Breeding

Dr. P.K. Shrotia Professor, Genetics and Plant Breeding

Dr. N.K .Singh SRO, Genetics and Plant Breeding

Dr. R.K. Khulbe JRO, Genetics and Plant Breeding

Dr. B. Kumar Professor & Head, Agriculture Communication

Dr. Shivendra Kashyap Assoc. Professor, Agriculture Communication

Dr. N.S. Murty Prof. & Head, Agrometereology

Dr. A.S. Nain Asstt. Professor, Agrometereology

Dr. Anil Kumar Professor and Head, MBGE

Dr. A.K. Gaur Professor, MBGE

Dr. Reeta Goel Professor & Head, Microbiology

Dr. K.P. Singh Assoc. Professor, Physics

Dr. Anil Sharma Assoc. Prof., Biological Science

Dr. Uma Melkania Prof. & Head, Environmental Science

Dr. Veer Singh Professor, Environmental Science

Dr. A.K. Pant Professor & Head, Chemistry

Dr. Shishir Pant Asstt. Professor, Chemistry

Dr. Anjana Srivastava Asstt. Professor, Chemistry

Dr. S.B. Singh Assoc. Professor, Mathematics

Dr. R.S. Rajput Asstt. Professor, Computer Science

Dr. Balwinder Singh Assoc. Prof., Vet. Anatomy

Dr. T.C. Thakur National Professor, Farm Machinery & Power Engineering

Dr. T.P. Singh Professor, Farm Machinery & Power Engineering

Dr. Samant Ray Professor, Computer Engineering

Dr. P.K. Singh SRO, Irrigation and Drainage Engineering

Dr. R.P. Singh Associate Director, Directorate of Extension Education

Dr. K.P. Singh Professor, Plant Pathology, Hill Campus Ranichauri

ii

ANNEXURE-IV

CENTRE OF ADVANCED FACULTY TRAINING IN PLANT PATHOLOGY G.B. Pant University of Agric. & Tech., Pantnagar-263 145 (UK)

Course Schedule (March 23 to April 12, 2011)

“Climate change, precision agriculture and innovative disease control strategies”

Venue : PG Lab- Department of Plant Pathology

Day & Date Time Topic ( Lecture/ Lab) Speaker/Contact

Wednesday

March 23

09:30-10:30 hrs Registration & Introduction with Plant Pathology Faculty Venue: PG Lab, Plant Pathology

Registration Committee

10:30-11:30 hrs Department of Plant Pathology and CAFT activities at Pantnagar

Dr. J. Kumar, Director, CAFT

11:30-11:45 hrs Tea Break

11:45-13:00 hrs T.A. claims & settlement Dr. R.P. Awasthi

13:00-14:30 hrs Lunch

14:30-17:00 hrs Visit of different research centre of the university Dr. Vishwanath

Thursday

March 24

09:30-10:30 hrs College of Agriculture at a Glance Dean Agriculture

10:30-11:30 hrs Climate change and Plant Disease Dr. H.S. Tripathi


11:45-13:00 hrs Visit to Plant Pathology Labs and MRTC Dr. R.P. Singh/ Y. Singh

13:00-14:30 hrs Lunch

14:30-15:30 hrs Climate change and food security Dr. Veer Singh


15:45-17:00 hrs Disease Prediction and precision agriculture Dr. V.S. Pundhir

Friday

March 25

10:00-11:00 hrs Inaugural Function

Venue: Conference Hall, Agriculture College


11:30-13:00 hrs Climate change and mitigatory measures with reference to hill agriculture

Dr. Uma Melkania

13:00-14:30 hrs Lunch

14:30-17:00 hrs Visit to Univ. Library & KNSCCF Dr. R.K. Sahu

Saturday

March 26

09:30-10:30 hrs Weather and plant disease forecasting Dr. N.S. Murty

10:30-11:30 hrs Impact of agricultural intensification on carbon sequestration, soil health and nutritional quality

Dr. K.P. Raverkar


11:45-13:00 hrs Seed health testing: retrospect and prospect Dr. K. Vishunavat

13:00-14:30 hrs Lunch

14:30-15:30 hrs Communication skills for teaching professionals Drs. B. Kumar & Shiven Kashyap


15:45-17:00 hrs Communication skills for teaching professionals Drs. B. Kumar & Shiven Kashyap

Sunday

March 27

09:30-17:00 hrs Visit of Indo-dutch project, Chafi, Bhimtal/Research Centre Patuwadangar/ARIS Nainital

Dr. Vishwanath

Monday

March 28

09:30-10:30 hrs Climate change in social perspective Dr. R.P. Singh, DEE

10.30-11.30 hrs Resource conservation techniques in plant health disease and management

Dr K. P. Singh

i


11:45-13:00 hrs Role of eco-friendly approaches in integrated pest and disease management

Dr. Ruchira Tewari

13:00-14:30 hrs Lunch

14:30-15:30 hrs Advances in electron microspy and application in plant pathology

Dr. Balvinder Singh


15:45-17:00 hrs Visit of EM Lab Dr. Balvinder Singh

Tuesday

March 29

09:30-10:30 hrs IPR issues in agriculture Dr. H.S. Chawla

10.30-11.30 hrs Plant disease management in precision farming Dr. V.S. Pundhir


11:45-13:00 hrs Microarray applications of rhizospheric community analysis for introducing bioagents in organic farming

Dr. A.K. Gaur

13:00-14:30 hrs Lunch

14:30-15:30 hrs GIS application in precision farming Dr. A.K. Agnihotri


15:45-17:00 hrs Visit of GIS Lab Dr. A.K. Agnihotri

Wednesday

March 30

09:30-10:30 hrs Innovations in plant disease management through microbes

Dr. Anil Sharma

10:30-11:30 hrs Nano-technology: A modern technological tool for precision agriculture.

Dr. K.P. Singh, CBSH


11:45-13:00 hrs Knowledge transfer issues and successes in relation to plant pathology

Dr. K.P. Singh

13:00-14:30 hrs Lunch

14:30-17:00 hrs Visit to University Library

Thursday

March 31

09:30-10:30 hrs Management of key nematode pests of field and horticultural crops

Dr. Rakesh Pandey

10:30-11:30 hrs Biological Control of Frost Injury: Role of Ice Nucleating Bacteria

Dr. S.C. Saxena


11:45-13:00 hrs Plant Pathology & Food Security Dr. J. Kumar

13:00-14:30 hrs Lunch

14:30-17:00 hrs Visit of Automatic weather station and observatory at CRC Dr. H.S. Kushwaha

Friday

April 01

09:30-10:30 hrs Toxicological investigations on the emerging pest problems in the important crops

Dr S.N. Tiwari

10:30-11:30 hrs HPLC: An important tool for assessment of pesticides residue in crops

Dr. Anjana Srivastava

11:30-11:45 hrs Tea Break 11:45-13:00 hrs Novelties in mango malformation research Dr. D.K.

Chakrabarty 13:00-14:30 hrs Lunch 14:30-15:30 hrs Precision farming for higher productivity and

profitability Dr. Rajeev Kumar


15:45-17:00 hrs Overcoming nutritional deficiencies and toxicities in crop plants

Dr. P.C. Srivastava

Saturday

April 02

09:30-10:30 hrs Current status of forecasting of late blight of potato Dr. V.S. Pundhir

10:30-11:30 hrs Use of variable rate farm machinery in precision farming

Dr. T.C. Thakur


11:45-13:00 hrs Bio-control strategy for the management of threatening diseases

Dr. N.W. Zaidi

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13:00-14:30 hrs Lunch

14:30-15:30 hrs Presentation by Participants



Sunday

April 03

09:00 hrs. Departure to Ranichauri

Monday

April 04

09:00-10:00 hrs Visit of Green House Gas Monitoring Station Dr. Vijendra Kumar/IMD Scientist

10:00-11:00 hrs Academic activities of Hill Campus Dr M C Nautiyal

11.00-12.00 hrs Forecasting of apple scab Dr. K.P. Singh

12.00-13:00 hrs Climate change in mid Himalayan reason Dr. R.K. Singh

13:00-14:00 hrs Lunch

14:00-17:00 hrs Visit of IPM Demonstrations at Farmers field. Dr. K. P. Singh/

Dr. Vijendra Kumar

Tuesday

April 05

08:00 hrs Departure to Forest Research Institute, Dehradun

11:00 hrs Arrival in Forest Research Institute, Dehradun

11:00-12:00 hrs Mycorhizae, bamboo and carbon sequestration Dr Y.P. Singh, FRI

12.00-13.00 hrs Visit of Forest Pathology Museum Dr. Amit Pandey

13:00-14:00 hrs Lunch

14:00-15:30 hrs Visit of Forest Research Institute

15:30 hrs. Departure to Pantnagar

Wednesday

April 06

09:15-09:30 hrs Group photograph

09:30-10:30 hrs Plant Healthcare for Resource Poor Farmers – Technologies for Disease Management in Low Input Systems

Dr. J. Kumar

10:30-11:30 hrs Metagenomics-A tool for identification and characterization of uncultivable microbial diversity

Dr. Reeta Goel


11:45-13:00 hrs Impact of Climate change on plant pathogen interaction

Dr. Rupam Kapoor

13:00-14:30 hrs Lunch

14:30-15:30 hrs Soil solarization and its application in plant disease management

Dr. Y. Singh


15:45-17:00 hrs Drip irrigation for precision farming Dr. P.K. Singh

Thursday

April 07

09:30-10:30 hrs Ancient crop protection practices: relevance as on now

Dr. S.L. Chaudhary

10:30-11:30 hrs Induced systemic resistance against white rust of rapeseed & Mustard

Dr. R.P. Awasthi


11:45-13:00 hrs Cultivar mixtures in plant disease management Dr. P.K. Shrotia

13:00-14:30 hrs Lunch

14:30-15:30 hrs Application of SAS in Biological Sciences Drs. S.B. Singh/ R.S. Rajput


15:45-17:00 hrs Application of SAS in Biological Sciences Drs. S.B. Singh/ R.S. Rajput

Friday

April 08

09:30-10:30 hrs Future prospects of immunological assays for the detection of plant pathogens

Dr. Anil Kumar

10:30-11:30 hrs ICT applications in agricultural research and knowledge management

Dr. Samant Ray

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11:45-13:00 hrs Evaluation and application of promising Trichoderma isolates for the management of soil borne plant pathogen

Dr. A.K. Tewari

13:00-14:30 hrs Lunch

14:30-15:30 hrs Chaemo-prospecting for agrochemicals form nature: design and development of novel products.

Dr A.K. Pant


15:45-17:00 hrs Innovations in agrochemical formulation technology for safety and efficacy

Dr. Shishir Tandan

Saturday

April 09

09:30-10:30 hrs Innovations in agrochemical application technology for safety and efficacy

Dr. T. P. Singh, PCT

10:30-11:30 hrs Wheat rust and its impact on global wheat production Dr K. P. Singh


11:45-13:00 hrs Scenario of maize diseases in changing climate Dr K. S. Hooda

13:00-14:30 hrs Lunch

14:30-15:30 hrs Application of remote sensing in plant disease management

Dr. A.S. Nain


15:45-17:00 hrs Visit of remote sensing Dr. A.S. Nain

Sunday

April 10

09:30-10:30 hrs Role of plant genetic resources in plant disease management

Dr. R.K. Khulbe

10:30-11:30 hrs Demonstration of Biology microbial identification Dr R.P. Singh/

Laxmi Rawat


11:45-13:00 hrs Visit of rhizosphere biology lab Drs. Anil Kumar & Anil Sharma

13:00-14:30 hrs Lunch




16:45-17:15 hrs Observation of Biolog microbial identification Dr Laxmi Rawat

Monday

April 11

09:30-10:30 hrs Characterization of race profile and resistance to pathogens

Dr. J. Kumar

10:30-11:30 hrs Seed pieces transmissible diseases of sugarcane and three tier seed production programme

Dr. R.K. Sahu


11:45 12:45 hrs Managing disease through host resistance Dr. D. Roy

12:45-14:00 hrs Lunch

14:00-15:00 hrs Disease management in Protected Cultivation Dr R P Singh

15:00-16:00 hrs Engineering resistance against biotic stress affecting horticultural and field crops

Dr. N.K. Singh

16:00-17:00 hrs Closing function

Tuesday

April 12

09:30-10:30 hrs Climate change and its implication on disease dynamics in rice, wheat and legumes

Dr. S.C. Saxena




13:00-14:30 hrs Lunch

14:30-17:00 hrs Discussion and wrap-up session

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centre of advanced faculty training in plant pathology

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Transcript of centre of advanced faculty training in plant pathology