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Eco-friendlyAgril. J. 6(09): 193- 198,2013 (September)

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CorrespondenceA. Ahmed

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-THE GENETIC DIVERSITYOF'WHITE INBREDMUNESOF QUALITYPROTEINMAIZE (QPM)

"2 k ci. Amiruzzaman , A. Ahmed,- -- -- - - - -- --- -

Abstract

Genetic diversity of 24 white QPM inbred lines was estimated by using Mahalanobis 02statistic for eleven characters. The genotypes were grouped into four clusters. The inter-cluster distances were larger than intra-cluster distances, suggesting wider geneticdiversity among the genotypes of different groups. The cluster I and III contained thehighest number of genotypes. The highest mean values for kernel yield/plant, 1O00-kernelweight, number of kernels/row and number of kernels/ear were observed in cluster III.The mean of ear length was the highest in cluster II. The lowest mean values for days topollen shedding and days to silking were found in cluster IV. The highest inter-clusterdistance was observed between cluster I and III and lowest between cluster II and IV. Thehighest intra-cluster distance was noticed in cluster I and the lowest was in cluster IV.Number of kernels/row, ear length, kernel yield and days to pollen shedding and kernelyield/plant were found to contribute maximum towards total divergence. Based onmedium and high inter-cluster distances, per se performances and desirable characters,eleven inbred lines viz. CML 144, CML 159, CML 206, CML 247, CML 251, CML 264,

I CML 444, CML 488, CML 500, CML 503 and CML 511 were selected for futurehybridization program. Crossing between these genotypes have the chance to obtainhigher heterosis with high performing crosses.

Key words: Genetic diversity, White QPM inbred lines, Genotypes,Differentclusters

and in plant variety protection. Evaluation of geneticdiversity is important to know the source of genes for aparticular trait within the available germplasm(Tomooka,1991)Multivariate analysis is an useful tool for quantifyingthe degree of divergence between biologicalpopulation at genotypic level and in assessing relativecontribution of different components to the totaldivergence both intra-and inter-cluster level (Murtyand Arunachalam, 1966; Ram and Panwar, 1970 andSachan and Sharma, 1971). The present study wastherefore undertaken to analyze the genetic divergenceof QPM maize inbreds for producing nutritionally richQPM white hybrid variety.

Introduction

Maize (Zea mays L) plays a significant role in humanand livestock nutrition worldwide. It is the world'smost widely grown cereal and is the primary staplefood in many developing countries (Morris et aI.,1999). It is a versatile crop with wider geneticvariability and able to grow successfully throughoutthe world covering tropical, subtropical and temperateagro-climaticconditions.Maize in Bangladesh is becoming an important crop inthe rice based cropping system. It is the third importantcereal crop after rice and wheat. In recent year's maizeis gainingpopularity among the farmers mainly due tohigh yield, more economic return and versatile uses. Itis the highest yielding grain crop having multiple uses.The area and production of maize is increasing day byday in Bangladesh and it continues to expand rapidlyat an average rate of 20% year-l (CIMMYT, 2008).AlthoughBARI has developed a open-pollinated whitemaize variety but there is no nutritionally rich (lysineand tryptophan enriched) white maize hybrid variety inBangladesh.Genetic diversity in maize is a valuable naturalresource and plays a key role in hybrid breedingprogram. Knowledge of germplasm diversity and therelationship among elite breeding materials has asignificant impact on the improvement of crop plants(Hallauer et aI., 1988). In maize, this information isuseful in planning crosses for hybrid and linedevelopment, in assigning lines to heterotic groups,

Materials and Methods

Twenty four white quality protein maize (QPM) inbredlines were grown in a alpha lattice design with threereplications at the Bangladesh Agricultural ResearchInstitute (BARI), Gazipur during rabi 2009-10. Seedswere sown on 23 November 2009. The seeds of eachinbred lines were sown in a single row of 5 m longplot. Spacing adopted was 75 x 20 cm between rowsand hills, respectively. One healthy seedling per hillwas kept after proper thinning. Fertilizers were applied@ 120,80,80,20, 5 and 1 kglha ofN, P2Os,K2O, S, Znand B respectively. Standard agronomic practices werefollowed (Quayyum, 1993) and plant protectionmeasures were taken when required. Data on days to50% pollen shedding and silking were recorded on

Amin et Qt. Genetic diversity of maize

whole plot basis. Ten randomly selected plants wereused for recording observations on kernel yield/plant(g), plant height (em), ear height (em), number ofkernel rows/ear, number of kernels/row, ear length(em), ear diameter (em), lOOO-kernelweight (g), huskcover (1-5 scale) and disease reaction(1-5 scale).Genetic diversity was estimated using Mahalanobisgeneralized distance (D2) extended by Rao (1952).Tocher's method was followed to determine the groupconstellation. Canonical variate analysis was alsoperformed as per Rao (1964) to confirm the results ofcluster D2 analysis. The data were analyzed usingGENSTAT 5.0 software program.

are presented in Table 1. Significant differences wereobserved among the lines for all the characters studiedand therefore diversity analysis was carried out.The twenty four inbred lines were grouped into fourdifferent clusters by using clustering techniques. Thedistribution of the genotypes in different clusters ispresented in Table 2. The maximum number ofgenotypes (7) was grouped in cluster I and III followedby 5 each in cluster II and IV.The intra-and inter-cluster values within and amongthe clusters are presented in Table 3. Intra-groupdistances appeared much smaller than the inter-groups,suggesting a lower genetic diversity among the lines ofthe same group than those from different groups. Thisis corroborated with the results of Ivy et al. (2007) andHoque et al. (2008).

Results and Discussion

The mean performances of24 white QPM inbred lines

*1= excellent, 5= unaccepted; ** 1= resistant, 5= susceptible, TLB: Turcicum leaf blight

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Table 1. Mean performances of 24 white QPM inbred lines of maize evaluated at Joydebpur during rabi 2009-10

Inbred lines Days to pollen Days to Plant height Ear height **Disease TLBsheddin silkin (em (em) (1-5 scale)

1. CML 144 95 99 120 42 1

2. CML 159 93 95 106 33 1

3. CML 202 97 99 il8 45 2

4. CML 206 90 92 120 42 I

5. CML 216 92 94 III 48 3

6. CML 247 97 101 125 52 1

7. CML 251 96 97 127 54 1

8. CML 254 98 102 129 54 2

9. CML 264 97 100 103 29 I

10. CML 376 87 90 120 43 I

11. CML 395 96 99 138 57 3

12. CML 444 91 93 115 55 1

13. CML 448 90 90 124 45 2

14. CML 456 98 105 132 42 I

15. CML 488 96 99 125 35 1

16. CML 491 90 92 139 60 317. CML 498 97 101 ill 36 2

18. CML 500 99 104 131 51 1

19. CML 503 92 94 98 29 1

20. CML 504 88 91 92 34 2

21. CML 505 99 103 128 45 1

22. CML 507 90 92 116 38 2

23. CML 509 89 92 128 41 2

24. CML 511 93 96 93 27 I

Minimum 87 90 92 27

Maximum 99 104 139 60

Mean 93 96 119 43

F- test ** ** ** **

CV (%) 0.54 0.69 3.44 7.95

LSD5% 1.01 1.22 8.32 6.99

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Table 1. Contd.

Genetic diversity of maize

Inbred lines

I. CML 144

2. CML 159

3. CML 202

4. CML 206

5. CML 216

6. CML 247

7. CML 251

8. CML 254

9. CML 264

10. CML 376

11. CML 395

12. CML 444

13. CML 448

14. CML 456

15. CML 488

16. CML 491

17. CML498

18. CML 500

19. CML 503

20. CML 504

21. CML 505

22. CML 507

23. CML 509

24. CML 511

Minimum

Maximum

Mean

F-test

CV (%)

LSD 5%

9.1

12.1

11.1

4.06

0.91

**

Intra-cluster distances varied from 0.6927 to 0.9035,the maximum being with cluster I and minimum incluster IV. Comparatively, higher intra-clusterdistances were observed in cluster I and III, and cluster1and IV, yet they were not so far diversed from others.The maximum inter-cluster distance was observedbetween clusters I and III (11.37). Medium orintermediatedistances were observed between cluster Iand IV (8.84), II and III (8.78) and I and II (7.18). Thelowest distance was shown between cluster II and IV(4.06). The genetic differences between clusters werereflected in their cluster means. Mean values fordifferentclusters are presented in Table 4. The highestmean values for kernel yield/plant, 1ODD-kernelweight, number of kernels/row and number of kernelsfear were observed in the same cluster III (Table 4).

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This means lines included in this group are better forthese parameters. Cluster III also had the lowest valuefor plant height and ear height. This cluster alsopossessed high values for yield and most of the yieldcomponents and also maintained a good husk cover(Table 1). The mean of ear length was the highest incluster II. The lowest mean values for days to pollenshedding and days to silking were found in cluster IV.Contribution of the characters towards divergence ispresented in Table 5. Results showed that, Vector Iobtained from PCA expressed that the importantcharacters responsible for genetic divergence in themajor axis of differentiation were days to silking, plantheight, ear height and number of kernels/ear. In vectorII, which is the second axis of differentiation, theresponsible characters were ear diameter, number of

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Ear diameter No. of kernel No. of No. of Kernel yield/(em) rows/ear kernels/ row kernels/ ear lant ( )3.9 12 25 321 57.5

3.7 12 18 216 42.0

3.8 12 22 248 48.5

4.3 12 25 297 68.5

3.4 10 20 190 57.5

3.9 12 24 304 49.0

3.5 12 26 297 58.5

3.8 10 19 188 51.5

3.8 10 20 204 50.5

3.8 12 24 286 47.5

4.3 12 23 268 46.0

4.2 12 24 274 64.5

4.0 12 22 256 47.0

3.6 10 19 191 56.0

4.1 12 25 298 70.5

3.8 12 25 300 45.5

3.9 10 21 197 58.0

3.5 12 24 266 57.0

3.7 14 23 308 63.0

4.2 12 22 249 50.5

4.0 12 23 276 60.5

4.1 10 18 182 52.5

3.9 12 22 265 58.0

4.1 12 23 280 62.5

3.4 10 18 182 183.0 45.5

4.3 14 25 321 294.0 70.5

3.9 12 22 257 238 54.1** ** ** ** ** **

7.60 4.31 8.93 3.17 1.72 9.41

0.61 0.73 4.09 16.71 8.57 10.57

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kernel rows/ear, number of kernels/row and ear lengthplayed their major role on genetic divergence.

Table 2. Distribution of24 white QPM inbred lines ofmaize in four different clusters

Table 3. Intra (bold) and inter-cluster distances of 24white QPM inbred lines of maize

Days to pollen shedding, ear length, number ofkernels/row and kernel yield/plant showed positivevalues in respect to both the vectors, were the majorimportant traits responsible for genetic divergence inthe major axis of differentiation. This means thatconsiderable emphasis should be given on thoseparameters responsible for genetic divergence. Theabove results are partially agreed with that of Alika etat. (1993), who reported the higher contribution ofdays to tasseling towards total genetic divergence inmaize. Contrarily, Datta and Mukherjee (2004)

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Genetic diversity of maize

observed very little role of days to tasseling and daysto silking in the discrimination of inbred lines. Theyconcluded that important yield components like earweight, ear length and kernel weight had considerablecontribution towards divergence of different maizeinbred lines in their study. Maximum contribution ofdays to tasseling, kernel weight and kernel yield/planttowards diversity of maize was also reported byAmiruzzaman (2010).

Table 5. Relative contribution of different characters tothe total divergence in maize

Based on generalized group distance, Behl et at.(1985) and Mian and Bahl (1989) opined that, theinter-varietal crosses involving low inter-clusterdistance was not heterotic. Contrarily, optimumheterosis was obtained ITom intermediate values andtapered off with higher level of divergence. Similarly,Ramanujam et al. (1974) and Ghaderi et at. (1984)also reported that parental clusters separated by 02values of intermediate magnitude generally showedhigher heterosis for kernel yield and yield componentsin their study.In a study with maize, Moll et al. (1962) observedincreased heterosis with increased genetic diversity.However, later, Moll et al. (1965) again reporteddecreased heterosis in crosses with varieties of extremediverse nature. In addition, they also obtained higherheterosis ITom optimal level of diversity, beyondwhich heterosis did not increase or may evendecreased. Gallais (1984) stated that extreme diversityor very related parents decreased heterosis. On thecontrary, Nigussie and Zelleke (2001) reported thatheterosis in maize tends to increase with increases indivergence among parents with respect to geographicalorigin.Vasal et al. (1998) suggested to select parents withhigh per se performance for obtaining heteroticcombination. They also reported that superior hybridperformance and continuing yield advantages shouldbe achieved through combined effects and strategies

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Cluster I No.of I Genotypes in different clustersgenotypes

I7 CML 159, CML 216, CML 254,

CML 264, CML 456, CML 498 andCML 507

II 5 CML 202, CML 247, CML 395,CML 448 and CML 491

III 7 CML 144, CML 251, CML 488,CML 503, CML 505, CML 509 andCML 511

IV 5 CML 206, CML 376, CML 444,CML 500 and CML 504

clusters]I

I

III

III

0.9035 7.18 11.37 8.84

II 0.7623 8.78 4.06

III 0.8321 4.84

IV 0.6927

Table4. Clustermeans for differentcharactersof 24whiteQPMinbredlinesof maize

Characters I Clustermeans

0 II I III

Days to pollen shedding 94 93 94 91

Days to silking 98 96 97 94

Plant height.(cm) 115 129 110 119

Ear height (cm) 40 52 39 45

Ear length (cm) 10.7 11.6 11.3 11.2

Ear diameter (cm) 3.7 4.0 3.9 4.0No. ofkemel rows/ear 10 12 12 12

No. ofkemels/row 19 23 24 23

No. of kernels/ear 195 275 292 274

1000-kernel weight (g) 228 196 278 236

Kernel yield/plant (g) 52.6 47.2 58.1 57.6

Characters I Vector I I Vector II

Days to pollen shedding 0.1188 0.1507

Days to silking 0.2521 -0.3588

Plant height.(cm) 0.0257 -0.0009

Ear height (cm) 0.0092 -0.0657

Ear length (cm) 0.8682 0.6874

Ear diameter (cm) -3.1462 1.9794

No. of kernel rows/ear -2.6161 1.2212

No. of kernels/row 1.543 0.8665

No. of kernels/ear 0.0416 -0.0443

1000-kernel weight (g) -0.0757 -0.0452

Kernel yield/plant (g) 0.1085 0.1278

Amin et af.

involving improved inbred performance, cross-bredperformance and on diversity. According to theminbred performance is a device factor in choosinghybrid options. Similar conclusion was drawn byDuvick (1999) who also reported that, the higheryielding inbreds have consistently tended to producethe higher yielding hybrids. Therefore, duringselection of parents, per se performances of the inbredlines were kept in mind.According to the above review of references, it isexpected that crosses between the inbred linesbelonging to cluster II with III and between cluster Iand IV, I and II and I with III having medium to highD2 values had the chance to exhibit high heterosis,earliness, dwarf type plants and higher level ofproduction.Based on medium and high inter-cluster distances, perse performances and desirable traits, the white QPMinbred lines CML 159 and CML 264 from cluster I;CML 247 from cluster II; CML 144, CML 251, CML488, CML 503 and CML 511 from cluster III andCML 206, CML 444 and CML 500 from cluster IVwere selected for future hybridization program.

Conclusion

The crosses between the above mentioned selectedinbreds of cluster 11with III; 1with those of II, III andIV would be expected to exhibit high heterosis withrecombinants of desired characters in maize. It can beconcluded that kernel yield, number of kernels/row,ear length, and days to pollen shedding contributedmaximum towards divergence. Hence major emphasisshould be given on those characters for selectingparents for hybridization in maize.

References

Alika JE, Aken'ova ME and Fatokun CA. 1993.Variation among maize (Zea mays L)accessions of Bandel State, Nigeria.Multivariate analysis of agronomic data.Euphytica, 66: 65-71.

Amiruzzaman M. 2010. Exploitation of hybrid vigourfrom normal and quality protein maize hybrids.Ph.D. dissertation. Dept. of Genetics and PlantBreeding, Bangladesh Agricultural University,Mymensingh. pp. 42-55.

Behl RK, Singh VP and Paroda RS. 1985. Geneticdivergence in relation to heterosis and specificcombining ability in triticale. Indian J. Genet.,45: 368-375.

CIMMYT (International Maize and WheatImprovement Center). 2008. Achievements ofthe Bangladesh-CIMMYT partnership foragricultural research and development.CIMMYT-Bangladesh, Banani, Dhaka. pp. 1-9.

Eco-friendly Agril. J.

Genetic diversity of maize

Datta D and Mukherjee BK. 2004. Genetic divergenceamong maize (Zea mays L) inbreds andrestricting traits for group constellation. IndianJ. Genet., 64: 20]-207.

Duvick DN. 1999. Heterosis: Feeding people andprotecting natural resources. In Coors, J.G. andS. Pandey (ed.). The Genetics and Exploitationof Heterosis in Crops. American Society ofAgronomy, Inc., Crop Science Society ofAmerica, Inc., Soil Science Society of America,Inc., Madison, WI. USA, pp. 19-29.

Gallais A. ]984. An analysis of heterosis vs.inbreeding effects with an autotetraploid crossfertilized plant Medicogo sativa L. Genetics,]06: 123-137.

Ghaderi A, Shishegar M, Regai A and Ehdaie B. 1984.Multivariate analysis of genetic diversity foryield and its components in mungbean. J. Amer.Soc. Hort. Sci., 104: 728-731.

Hallauer AR, Russell WA and Lamkey KR.] 988. ComBreeding. In: Sprague, G.F.and J.W. Dudley(eds). Com and Com Improvement, 3rd edn.Agron Monogr 18. ASA, CSSA; and SSSA,Madison,Wisconsin, USA.

Hoque M, Asaduzzaman M, Rahman MM, Zaman Sand Begum SA. 2008. Genetic divergence inmaize (Zea mays L). Bangladesh J. Agric.,9:145-148.

Ivy NA, Uddin MS, Sultana Rand Masud MM. 2007.Genetic divergence in maize (Zea mays L).Bangladesh J. PI. Breed. Genet., 20: 53-56.

Mian MAK and Bahl PN. 1989. Genetic divergenceand hybrid performance in chickpea. Indian J.Genet., 49: 119-124.

Moll RH, Saluana WS and Robionso HF. 1962.Heterotic and genetic diversity in varietycrosses of maize. Crop Sci., 2: 197-198.

Moll RH, Lonnquist JH, Fortune JV and Johnson Ee.1965. The relationship of heterosis and geneticdivergence in maize. Genetics, 52: 139-144.

Morris ML, Risopoulos J and Beck D. 1999. Geneticchange in farmer-recycled maize seed; a reviewof the evidence. CIMMYT Economic WorkingPaper No. 99-07. Mexico, D.F., CIMMYT, 1p.

Murty BR and Arunachalam V. 1966. Geneticdivergence in wheat under differentenvironmental condition. Cereal Res. Comm., 6:307-317.

Nigussie M and Zelleke H. 2001. Heterosis andcombining ability in a diallel among eight elitemaize populations. African Crop Sci. J., 9: 471.

Quayyum MA. 1993. Bhuttar Chash Paddhati (inBengali). In: Chowdhury, M.K. and M.A. Islam(ed.). Bhuttar Utpadan 0 Babohar. BangladeshAgricultural Research Institute, Gazipur. pp. 43-48.

197

~

Amin et al.

Ram J and D.V.S. Panwar, 1970. Interspecificdivergence in rice (Oryza sativa L) Indian J.Genet., 30: 1-2.

Ramanujam S, Tiwary AS and Mehra RB. 1974.Genetic divergence and hybrid performance inmungbean. Theor. Appl. Genet., 44: 211-214.

Rao CR. 1952. Advanced Statistical Methods inBiometrical Research. John Wiley and Sons,New York.

Rao CR. 1964. The use and interception of principalcomponent analysis in applied research.Sankhya, 22: 317-318.

Raut VM, Rao VSP, Patel VP and Deodikar GB. 1985.Genetic divergence in Triticum durum. Indian J.Genet., 45: 141-151.

Sachan KS and Sharma JR. 1971. Multivariate analysisof genetic divergence in tomato. Indian J.Genet., 31: 86-93.

Eco-friendly Agril. J.

Genetic diversity of maize

Smith JSC, Chin ECL, Shu H, Smith OS, Wall OS,Senior SJ, Mitchell ML, Kresovich ME andZiegle SJ. 1997. An evaluation of the utility ofSSR loci as molecular markers in maize (Zeamays L): Comparison with data from RFLPsand pedigree. Theor. Appl. Genet 95: 163-173.

Tomooka N. 1991. Genetic diversity and landracedifferentiation of mungbean (Vigna radiata L)and evaluation of its wild relatives as breedingmaterials. Tech. Bull. Crop Res. Center, Japan.No. 28, Ministry of Agr., forestry and FisheriesofJapan. P. 1.

Vasal SK. 1998. Hybrid maize technology: Challengesand expanding possibilities for research in thenext century. In: Vasal, S.K., C.F. Gonzalez andF. Xingming (ed). Proc. 7th Asian RegionalMaize Workshop. Los Banos, Philippines,February 23-27, pp. 58-62.

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