Postharvest Biology and Technology 52 (2009) 126–133

Contents lists available at ScienceDirect

Postharvest Biology and Technology

journa l homepage: www.e lsev ier .com/ locate /postharvbio

Biological indicators to estimate the prevalence of gray mold and hairlinecracks on table grapes cv. Thompson Seedless after cold storage

Juan Pablo Zoffoli a,∗, Bernardo A. Latorrea, Jessica Rodrigueza, José M. Aguilerab

a Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Casilla 306-22, Santiago, Chileb Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Casilla 306-22, Santiago, Chile

a r t i c l e i n f o

Article history:Received 28 July 2008Accepted 24 November 2008

Keywords:Botrytis cinereaDecayForecasting‘Thompson Seedless’Vitis vinifera

a b s t r a c t

Gray mold caused by Botrytis cinerea and hairline cracks are the major cold storage deterioration problemsof table grapes (Vitis vinifera). Currently, table grapes are treated with sulfur dioxide (SO2), but thistreatment does not sufficiently and consistently control B. cinerea. This is probably associated with latentinfections that are poorly controlled with SO2, and to the increased berry propensity to develop hairlinecracks following SO2 treatment. Therefore, the objective of this work was to obtain an early biological indi-cator to segregate grape lots at harvest to later develop according to the potential gray mold and hairlinecracks. In this study, it was possible to distinguish gray mold infections at the stylar end, cheek, and baseof the berries. However, on commercial SO2-treated lots of ‘Thompson Seedless’ table grapes, the occur-rence of gray mold after cold storage was best predicted (Y = 0.45X, R2 = 0.84, P < 0.001) by the number ofgray mold infections that developed at the base of the berry of surface-disinfected (100 �L L−1 SO2 for 1 h)grapes that were incubated at harvest in humid chambers (100% relative humidity) for 2 d at 0 ◦C then 5 dat 20 ◦C. Similarly, the occurrence of hairline cracks after cold storage was best predicted (Y = 1.48 + 0.51X,R2 = 0.66, P = 0.0002) by the number of hairline cracks induced at harvest by dipping berries in 0.1 mol L−1

citric acid, pH 2, for 3 h at 20 ◦C, and stained with 0.1 mol L−1 methylene blue for 30 s at 20 ◦C. At harvest,cuticle content and porosity also predicted the occurrence of hairline cracks after cold storage. However,the cuticle content at harvest did not significantly predict gray mold occurrence at the berry base aftercold storage. The occurrence of gray mold in commercial SO2-treated lots after cold storage was predictedby the prevalence of gray mold at the berry base at harvest. Similarly, the occurrence of hairline cracks

after cold storage was predicted by the ability to induce hairline cracks at harvest by acidic pH. Furtherrefinement in this research is needed before using these biological indicators to segregate table grape lots

1

pceMt((cgpm

0d

commercially.

. Introduction

‘Thompson Seedless’ (=Sultana) is one of the most widelylanted table grapes (Vitis vinifera L.) among the white seedlessultivars worldwide. It is produced in a wide range of agro-cological conditions in Australia, Brazil, Chile, Egypt, India, Israel,exico, South Africa, and the USA. In Chile, ‘Thompson Seedless’

able grapes are produced in a 1000 km axis from north to south27◦ to 35◦ S) from arid to mediterranean climatic conditionsNovoa and Villaseca, 1989). Decay and hairline cracks are the main

auses of ‘Thompson Seedless’ deterioration during storage. Theray mold fungus (Botrytis cinerea Pers.: Fr.) is the most aggressiveathogen during cold storage because it can grow at −0.5 ◦C, com-on storage temperature for table grapes (Nelson and Richardson,

∗ Corresponding author. Tel.: +56 26864159; fax: +56 25534130.E-mail address: Zoffolij@uc.cl (J.P. Zoffoli).

925-5214/$ – see front matter © 2008 Elsevier B.V. All rights reserved.oi:10.1016/j.postharvbio.2008.11.010

© 2008 Elsevier B.V. All rights reserved.

1967; Nelson, 1985). Additionally, ‘Thompson Seedless’ is a highlysusceptible cultivar to B. cinerea (Mlikota Gabler et al., 2003).Postharvest gray mold is associated with pre-harvest infection, andconidia remaining on the surface of stored grapes at harvest can alsocontaminate berries (McClellan and Hewitt, 1973; Nair et al., 1995;Latorre and Vásquez, 1996; Holz et al., 2003; Keller et al., 2003).

Sulfur dioxide (SO2) fumigation and the use of SO2-generatingpads are recommended to control contaminated berries duringstorage. Fumigation with SO2 has been extensively used as asurface disinfectant, applied before (Hanke and Auger, 1988),during, or immediately after packaging (Luvisi et al., 1992). TheSO2-generating pad releases SO2 gas inside the packaged grapes toarrest gray mold growth and prevent contact infections during cold

storage and transport (Nelson and Ahmedullah, 1972; Zoffoli, 2002).

It has been demonstrated that high concentrations of SO2promote hairline cracking that is characterized by fine and longcracks in stored grapes that cause a wet, juicy, and sticky conditionon berry surfaces (Zoffoli et al., 2008). Hairline cracks reduce berry

gy an

qattcTb

sgl(etpil

mdcamesoaatmt

tlgwaa

2

2

gydew2TtSctfst(2

2

3

J.P. Zoffoli et al. / Postharvest Biolo

uality and possibly favor gray mold development (Capellini etl., 1986). ‘Thompson Seedless’ is among the most susceptibleable grape cultivar to hairline cracking, and it has been reportedhat hairline cracking susceptibility increases with the use ofytokinin and overuse of gibberellic acid (Zoffoli et al., 2009).hese growth regulators are commercially applied to increaseerry size (Valenzuela and Lobato, 2000).

Currently, the SO2-treatments and cold storage (−0.5 ◦C) are notufficient to consistently preserve the high quality of Chilean tablerapes during marketing. This is probably due to the presence ofatent infections and hairline cracks, as was previously postulatedMcClellan and Hewitt, 1973; Latorre and Vásquez, 1996; Holzt al., 2003; Pezet et al., 2003; Zoffoli et al., 2008). Consideringhat high rates of SO2 during fumigation do not eradicate theathogen (Nelson, 1958) and that SO2 does not penetrate deeply

nto the berry tissue (Smilanick et al., 1990), it is unlikely thatatent infection can be controlled with SO2.

Models have been developed to predict the presence of grayold on table grapes. However, these models have been primarily

eveloped to improve the timing and efficacy of pre-harvest fungi-ide treatments (Avilés et al., 1995; Broome et al., 1995; Latorrend Rioja, 2002; Latorre et al., 2002). Prediction models based onicrobiological and molecular methods have been proposed to

stimate the risk of gray mold infection at harvest and during thetorage of table grapes (Cadle-Davidson, 2007; Harvey, 1955) andther species such as kiwifruit, pistachio, and prune (Michailidesnd Morgan, 1996; Luo and Michailides, 2003; Ma et al., 2003; Mand Michailides, 2004). Nevertheless, there is a need for a modelhat integrates biological properties of the berry and pre-harvest

anagement in order to estimate the risk of deterioration in storedable grapes.

A model to predict postharvest deterioration on SO2-treatedable grapes cv. Thompson Seedless would be useful to segregateots on the basis of their potential risk of developing postharvestray mold and hairline cracks. Therefore, the objective of this workas to obtain an early biological indicator to segregate grape lots

ccording to their potential for gray mold and hairline prevalencet harvest.

. Materials and methods

.1. Table grapes

Eight (2006–2007) and seven (2007–2008) commercial tablerape ‘Thompson Seedless’ vineyards, which were five to eightears old, were selected in the Central Valley of Chile. The potentialevelopment of gray mold during cold storage was estimated usingight cluster samples per vineyard, 10 d before harvest. Each clusteras placed in a humid chamber (100% relative humidity) at 0 ◦C ford and then at 20 ◦C for 5 d to assess the development of gray mold.his analysis facilitated the selection of vineyards according toheir predicted prevalence of gray mold during subsequent storage.elected vineyards were trained and managed using standardommercial practices in Chile such as overhead arbor (pergola)rellis systems, drip irrigation, and use of gibberellic acid (GA3) andorchlorfenuron (N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) totimulate berry growth (Valenzuela, 2000). Fungicide programso counteract powdery mildew (Erysiphe necator) and gray moldB. cinerea) were performed as is customary in Chile (Latorre,004).

.2. Table grape evaluation at harvest

In each of the selected vineyards, 46 clusters (approximately2 kg) were collected randomly from 10 vines at commercial

d Technology 52 (2009) 126–133 127

maturity (16–19% total soluble solids, TSS). Sixteen clusters wereused to characterize grape quality and to estimate the potentialgray mold and hairline crack in the laboratory. The other 30 clusterswere used to determine gray mold and hairline crack prevalenceafter cold storage.

Of the 16 cluster samples for each vineyard eight clusterswere left untreated and eight were surface disinfected with SO2using a fast release SO2 pad (0.25 g kg−1of sodium metabisulfite)(Merck, Darmstadt, Germany) included on the top of the fruitand covered with 0.3% perforated polyethylene bag for 12 h at20 ◦C. The release of SO2 inside the bag was measured with an SO2analyzer (Solus Plus®, ThermoGastech Inc., CA, USA) (Zoffoli et al.,2008). All clusters were incubated in humid chambers at 0 ◦C for2 d, followed by 5 d at 20 ◦C (100% RH) to determine the prevalenceof gray mold development at the base, stylar end, and at the cheekof the berries (Holz et al., 2003).

Table grape quality evaluated included TSS content measuredwith a thermo-compensated refractometer (Atago, Italy) andtitratable acidity by titration (4 g L−1 NaOH to pH 8.2). Firmnesswas measured with a Durofel instrument provided with a 10-mmtip (Copa Technology, France) on a 0–100 scale where 0 = soft and100 = firm. Cluster compactness was estimated by the numberof berries per rachis length. Pedicel thickness and the lengthand width of the berries were measured with a digital caliper.Cuticle content, microcracks, and micropore density were evalu-ated at harvest. Cuticle content was determined on 70 skin disks(each of 50 mm2) obtained with a cork borer from the cheeksof 35 berries per vineyard. The cuticle proper/epicuticular waxlayer was then separated from the underlying epidermal celltissue by soaking each sample in 0.22 mol L−1 ZnCl2 and 36% HClfor 24 h at room temperature (20–22 ◦C) (Holloway and Baker,1968). Disks were then rinsed three times with distilled waterand the cuticles were dried at 30 ◦C for 2 h before weighingthem.

Two samples, consisting of 10 skin disks (each of 50 mm2), wereremoved from the outer layer in the middle portion of 10 berriesper vineyard, and used to determine the number of microcracksand the micropore density.

Disk tissue incubated in 0.1% Acridine Orange in 0.05 mol L−1

citric acid buffer, pH 6.5, containing 0.5% Tween 20 (Peschel andKnoche, 2005) for 4 min was examined for microcracks under a UVepifluorescent microscope (Nikon Optihop II, Tokio, Japan) withNikon filter module B-2A, � = 450–490 nm excitation, � = 520 nmemission and 40× magnification.

Disk tissue, obtained after dipping berries in 10% fluorescein(Sigma Chemical Co., St. Louis, MO, USA) for 5 min followed byrinsing in deionized water for 30 s, was examined for microporesunder a UV epifluorescent microscope (Nikon Optihop II, withNikon filter UV-2A � = 330–380 nm excitation, 40× magnification).Micropore density was expressed as the number of micropores per50 mm2 disk (Mlikota Gabler et al., 2003). The porosity (proportionof fluorescent area of the 50 mm2 disk) of skin tissue, observablewith the naked eye after samples were excited under 330–380 nmUV light, was determined.

To predict the prevalence of hairline cracks during subsequentstorage, hairline cracking was assessed on 100 berries frompedicels per vineyard that were randomly sampled at harvest.Berries were immersed in a 0.1 mol L−1 citric acid, pH 2, for 3 hat 20 ◦C. Hairline cracks were detected after staining the berrieswith 0.1 mol L−1 methylene blue (Merck, Darmstadt, Germany)for 30 s followed by a brief rinse with tap water. Hairline cracks

were rated on a 1–4 scale based on the proportion of berrysurface affected: <4% (very low), 5–6% (low), 6–12% (moderate),and >12% (severe) (Zoffoli et al., 2008). However, only mod-erately and severely affected berries were considered in thisstudy.

1 gy an

2

apaS0u

Fta

28 J.P. Zoffoli et al. / Postharvest Biolo

.3. Table grape evaluation after storage

Three boxes of five clusters each were left untreated andnother three boxes were treated with one SO2 generator pader box, providing fast and slow release phases of 0.22 g kg−1

nd 1.1 g kg−1 sodium metabisulfite, respectively (Uvas Quality,antiago, Chile). The SO2-treated grapes were stored for 45 d at◦C, and 3 d at 20 ◦C while the non-SO2-treated grapes were eval-ated after 10 d at 0 ◦C and 3 d at 20 ◦C. Table grapes were packed

ig. 1. Symptoms of gray mold caused by Botrytis cinerea and hairline cracks on table grahe berry, (B) brown discoloration at the base of the berries, (C) brown discoloration at thecid. (For interpretation of the references to color in this figure legend, the reader is refer

d Technology 52 (2009) 126–133

into a 0.30 m × 0.40 m carton box, and prior to storage, they weresubjected to 12 h of forced-air cooling at 0 ◦C to lower pulp temper-ature from 25 ◦C to 0–4 ◦C, with the aid of a portable cooling tunnel(1 L s−1 kg−1).

Postharvest evaluation included the percentage by weight of

gray mold infected berries, showing symptoms on the cheek, base,and distal ends (Fig. 1; Holz et al., 2003). Postharvest hairlinecrack prevalence was determined on 100 randomly selectedberries per box. Berries were stained in 0.1 mol L−1 methylene

pes (Vitis vinifera) cv. Thompson Seedless. (A) Small necrotic spots at the cheek ofstylar end and (D) hairline cracks induced after dipping berries in 0.1 mol L−1 citric

red to the web version of the article.)

gy an

bibp

2

dmnapMos

Faam

J.P. Zoffoli et al. / Postharvest Biolo

lue as described above. Split berries were recorded after visualnspection of all berries from five clusters. Shatter was determinedy the percentage weight of the loose berries in five clusterser box.

.4. Statistical analysis

To predict the prevalence of gray mold and hairline cracksuring subsequent storage, cuticle content, micropore andicrocrack densities, and quality parameters (TSS content, firm-

ess, berry size, pedicel thickness) were estimated at harvest

nd regressed against the actual gray mold and hairline crackrevalence after storage using Statgraphic (Systat Software, Inc.,aryland, USA) with P < 0.05. Analysis of variance was performed

nly when normality and homogeneity of variance tests wereignificant (P > 0.05).

ig. 2. Gray mold, caused by Botrytis cinerea (%) and hairline crack prevalence (%) on tablet 20 ◦C in SO2-treated or non-treated table grape, respectively in 2006–2007 (dark bars) and after SO2-treatments. SO2-treated grapes were packed with one SO2-generating padeans ± standard deviations are indicated.

d Technology 52 (2009) 126–133 129

3. Results

Gray mold symptoms at the cheek of the berry consisted ofsmall, spherical, reddish-brown spots of approximately 0.5 mm indiameter, which later developed the ‘slip skin’ symptom charac-teristic of gray mold (Fig. 1A). At the berry base and starting atthe pedicel insertion, gray mold infection was characterized bya reddish-brown decay often comprising vascular bundles andprogressing up to approximately one-third of the berry length, butslip skin was never observed. In this case, it was possible to removeberries while completely leaving the vascular bundles attachedto the pedicel (Fig. 1B). At the stylar end, gray mold symptoms

consisted of reddish-brown decay similar to that described at thebase of the berry (Fig. 1C). These symptoms were detected after45 d at 0 ◦C and 3 d at 20 ◦C.

At the berry base, gray mold prevalence on non-SO2-treatedtable grapes were 1.8–5.0% and 6.7–14.0% in the 2006–2007 and

grapes (Vitis vinifera) cv. Thompson Seedless after 45 d or 10 d at 0 ◦C followed by 3 dnd 2007–2008 (open bars). Grapes from the same vineyards were harvested beforeper 4.5 kg carton box. Mean of three replicates per each of 15 vineyards. Overall

130 J.P. Zoffoli et al. / Postharvest Biology and Technology 52 (2009) 126–133

F ray mc treateS

2dg

t((g

op

(r

FTR

ig. 3. Relationship between cuticle content at harvest and the prevalence (%) of gv. Thompson Seedless after 45 d or 10 d at 0 ◦C followed by 3 d at 20 ◦C, and eitherO2-generating pad per 4.5 kg carton box.

007–2008 growing seasons, respectively. Gray mold prevalenceecreased to 0–0.25% and 0–1.1% in 2006–2007 and 2007–2008rowing seasons on SO2-treated table grapes (Fig. 2).

At the berry cheek, gray mold prevalence on non-SO2-reated table grapes was 19.4–67.2% (2006–2007) and 8.2–24.9%2007–2008). Gray mold prevalence decreased to 0–0.4%2006–2007) and 0–0.6% (2007–2008) on SO2-treated tablerapes (Fig. 2).

Independent of the SO2 treatment, gray mold at the stylar end

f the berry was observed in five of 15 vineyards and diseaserevalence was 0.1–4.6% (data not shown).

On non-SO2-treated berries, a second order polynomial curveY = 371.6 − 198X + 27.8X2, R2 = 0.68, P = 0.001) best described theelationship between cuticle content at harvest and gray mold

ig. 4. Total actual gray mold after cold storage (45 d at 0 ◦C followed by 3 d at 20 ◦C) inhompson Seedless (n = 15). (A) Predicted of total gray mold at harvest, (B) predicted gray2 = 0.84, P < 0.0001.

old (Botrytis cinerea) that developed at the bases or cheeks of Vitis vinifera berriesd or not treated with SO2, respectively. SO2-treated grapes were packed with one

developed at the cheek of the berry after cold storage. No relation-ship was found between cuticle content at harvest and gray moldat the berry base after cold storage or on SO2-treated berries withgray mold development at the berry cheek or at the berry baseafter cold storage (Fig. 3).

On SO2-treated grapes, predicted total gray mold and gray moldat the cheek of the berry at harvest were not related to total graymold prevalence obtained after cold storage. However, predictedgray mold at the berry base was significantly related (P = 0.001)

to gray mold prevalence after cold storage (Fig. 4). Only the latterrelationship fulfills normality and constant variance assumptionsof the regression analysis.

A linear model using combined data from both growing seasonsexplained the relationship between potential gray mold at the base

relation to the gray mold (Botrytis cinerea) observed at harvest on Vitis vinifera cv.mold at the berry cheek, and (C) predicted gray mold at the berry base, Y = 0.45X,

J.P. Zoffoli et al. / Postharvest Biology and Technology 52 (2009) 126–133 131

Ftt

ob(

g5scs

s0mc(ma(flnc

hi

Fig. 7. Relationship between hairline cracks that were induced at harvest after dip-

author did not differentiate between gray mold that developed at

Fa

ig. 5. Relationship between the predicted gray mold (caused by Botrytis cinerea)hat developed at the base of Vitis vinifera berries at harvest and actual gray mold athe berry base observed after 45 d at 0 ◦C followed by 3 d at 20 ◦C.

f the berry obtained at harvest and gray mold prevalence at thease of the berry after cold storage (Y = 0.29X, R2 = 0.83, P < 0.0001)Fig. 5).

Hairline cracks, which developed mainly on SO2-treated tablerapes, were characterized by fine longitudinal cracks that were–10 mm in length and were mostly visible after berries weretained with methylene blue (Fig. 1D). Prevalence of hairlineracks fluctuated between 0.93% and 55.9% among the SO2-treatedamples from the 15 vineyards evaluated after storage (Fig. 2).

Hairline crack prevalence obtained on table grapes after coldtorage depended on the cuticle content at harvest and was–55% in 2006–2007 and from 0.3% to 48% in 2007–2008. A linearodel best explained the negative relationship between cuticle

ontent at harvest and hairline crack prevalence after storageY = 87.2 − 21.0X, R2 = 0.31, P = 0.03). Porosity of the berry skin, as

easured at harvest, was related to hairline crack prevalencefter cold storage. A linear model best explained this relationshipY = −8.8 + 1.35X, R2 = 0.60, P = 0.0007) (Fig. 6). Micropore densityuctuated from 4.6 to 18 micropores per 50 mm2 disk however,o relationship between micropore density at harvest and hairline

rack prevalence after cold storage was found (data not shown).

The potential development of hairline cracks, as determined atarvest, ranged from 0% to 70% in 2006–2007 and from 16% to 89%

n 2007–2008. The relationship between hairline crack potential

ig. 6. Relationship between cuticle content or porosity determined at harvest and the prt 0 ◦C followed by 3 d at 20 ◦C on grapes that were packed with one SO2-generating pad p

ping berries in 0.1 mol L−1 citric acid, pH 2, for 3 h at 20 ◦C, and the prevalence(%) of hairline cracks present after 45 d at 0 ◦C followed by 3 d at 20 ◦C, on SO2-treated Thompson Seedless, Vitis vinifera, table grapes that were packed with oneSO2-generating pad per 4.5 kg carton box.

and actual hairline crack prevalence after cold storage was bestdescribed by a linear model (Y = 1.48 + 0.51X, R2 = 0.66, P = 0.0002)(Fig. 7).

Percentage of shatter after storage was low (<2%) and was notrelated to gray mold infection obtained after storage (data notshown).

4. Discussion

According to the results obtained on ‘Thompson Seedless’ tablegrapes, the potential of gray mold developed at the berry base atharvest can best predict the risk of gray mold in commercial SO2-treated lots after cold storage. The potential gray mold obtainedat the berry cheek and at the distal end of the berries were notgood predictors of the presence of gray mold after cold storage.These results are similar to the gray mold forecasting previouslydeveloped by Harvey (1955), except that in this early work the

the berry base and that at the berry cheek probably because thiswas not relevant to the grape cultivar used.

Based on these results, the risk of hairline cracks developingduring cold storage can be predicted by the potential to induce

evalence of hairline cracks on Vitis vinifera berries cv. Thompson Seedless after 45 der 4.5 kg carton box.

1 gy an

hTcwp

pcogntcictacchHwotmrgiidaSdrci

wT1cmcp

phtaotwpmrsoch

A

I1

32 J.P. Zoffoli et al. / Postharvest Biolo

airline cracks just after harvest. Other berry parameters such asSS, TA, firmness, length and width, pedicel insertion width, clusterompactness, and the densities of micropores and microcracksere not useful as early predictors of gray mold and hairline crackrevalence after cold storage.

In agreement with a previous report (Holz et al., 2003), it wasossible to differentiate gray mold development at the stylar end,heek, and base of the berry (Fig. 1). The highest natural prevalencef gray mold consistently occurred at the berry cheek, followed byrowth at the berry base. Gray mold at the stylar end was almostegligible (Viret et al., 2004). This symptom differentiation appearso be important because it may reflect differences in the infectionounts that become available during berry growth and maturationn the vineyard. Differences in the efficacy of the SO2-treatmentsan be associated with differences in the infection counts leadingo symptom differentiation on the berries. For instance, it isccepted that the SO2-treatment, as it is typically used during theommercial handling of ‘Thompson Seedless’ grapes, effectivelyontrols conidia which can contaminate the surface of berries atarvest (Marois et al., 1986; Smilanick et al., 1990; Smilanick andenson, 1992), but it is less effective against gray mold infectionsithin the berry tissue, such as those at the berry base, which often

ccur long before harvest and remain latent until after harvest. Inhis study, gray mold at the berry base was less variable than gray

old at the berry cheek after cold storage (±S.D. = 3.7 and 18.8,espectively) reflecting less variability among vineyards and amongrowing seasons. Therefore, the potential to exhibit gray moldnfections at the berry base at harvest is proposed to be a biologicalndicator to segregate table grape lots into those with a low or highecay potential when subjected to SO2-treatments. The infectiont the berry base, although relatively low (prevalence <1.19%) onO2-treated grapes, can provide inoculum for secondary infectionsuring cold storage of these grapes. These infections result inejection at ports of entrance into the USA, Europe, and otherountries. For example, the maximum percentage of gray moldnfected grapes to meet the grade for U.S. No. 1 is 0.5% (USDA, 1999).

Gray mold prevalence at the berry cheek after cold storageas negatively correlated with the cuticle content at harvest.

hese results corroborate previous research (Comménil et al.,997; Broome, 1994; Zoffoli et al., 2009). However, the cuticleontent did not appear to be a predictor of the potential total grayold after cold storage. Apparently this was due to the fact that

uticle content at harvest was poorly correlated with gray moldrevalence at the berry base after cold storage.

In agreement with a previous report (Zoffoli et al., 2008), therevalence of hairline cracks on table grapes was considerablyigher on SO2-treated grapes than on non-SO2-treated grapes. Inhis study, the development of hairline cracks induced at harvestfter dipping berries in citric acid solution was the best predictorf the risk of the hairline cracks developing during cold storage ofable grapes. Cuticle content and porosity at harvest also predictedell the risk of hairline cracks after cold storage. However, theropensity to induce hairline cracks at harvest appears to be aore usable parameter than cuticle content and porosity. Further

esearch is needed before using these biological indicators toegregate lots of other table grape cultivars to estimate the riskf developing gray mold at the berry base or develop hairlineracks during cold storage base on observations made soon afterarvest.

cknowledgements

This research was funded by Conicyt (Comisión Nacional denvestigación), Científica y Tecnológica (Chile), Fondecyt grant no.050798.

d Technology 52 (2009) 126–133

References

Avilés, J.C., Broome, J.C., Latorre, B.A., Marois, J.J., 1995. El pronóstico en el manejo dela pudrición gris (Botrytis cinerea) de la vid. Aconex (Chile) 48, 13–17.

Broome, J.C., 1994. Cultural and chemical control of Botrytis bunch rot of table grapesin Chile. Ph.D. Dissertation. University of California, Davis, CA, 81 pp.

Broome, J.C., English, J.T., Marois, J.J., Latorre, B.A., Aviles, J.C., 1995. Developmentof an infection model for Botrytis cinerea bunch rot of grapes based on wetnessduration and temperature. Phytopathology 85, 97–102.

Cadle-Davidson, L., 2007. Early detection of natural Botrytis infections. In: Proceed-ings of the 1st Annual National Viticulture Research Conference, Davis, CA, USA,pp. 22–23.

Capellini, R.A., Ceponis, M.J., Lightner, G.W., 1986. Disorders in table grape shipmentsto the New York market, 1972–1984. Plant Dis. 70, 1075–1079.

Comménil, P., Brunet, L., Audran, J.C., 1997. The development of the grape berrycuticle in relation to susceptibility to bunch rot disease. J. Exp. Bot. 48, 1599–1607.

Hanke, T., Auger, J., 1988. El efecto de la gasificación inicial sobre la condición de lauva de mesa en postcosecha. Revista Antumapu (Chile) 2, 27–33.

Harvey, J.M., 1955. A method of forecasting decay in California storage grapes. Phy-topathology 45, 229–232.

Holloway, P.J., Baker, E.A., 1968. Isolation of plant cuticles with zincchloride–hydrochloric acid solution. Plant Physiol. 43, 1878–1879.

Holz, G., Gütschow, M., Coertze, S., Calitz, F.J., 2003. Occurrence of Botrytis cinereaand subsequent disease expression at different positions on leaves and bunchesof grape. Plant Dis. 87, 351–358.

Keller, M., Viret, O., Cole, M., 2003. Botrytis cinerea infection in grape flowers: defensereaction, latency and disease expression. Phytopathology 93, 316–322.

Latorre, B.A., 2004. Enfermedades de las Plantas Cultivadas, Sexta ed. Ediciones Uni-versidad Católica de Chile, Santiago, Chile, 638 pp.

Latorre, B.A., Rioja, M.E., 2002. Efecto de la temperatura y de la humedad relativasobre la germinación de Botrytis cinerea. Cien. Inv. Agr. (Chile) 29, 67–72.

Latorre, B.A., Vásquez, G., 1996. Situación de Botrytis cinerea latente en uva de mesade la zona Central. Aconex (Chile) 52, 23–28.

Latorre, B.A., Rioja, M.E., Lillo, C., 2002. Efecto de la temperatura en el desarrollo dela infección producida por Botrytis cinerea en flores y bayas de uva de mesa. Cien.Inv. Agric. (Chile) 29, 145–151.

Luo, Y., Michailides, T.J., 2003. Threshold conditions that led latent infection to prunefruit rot caused by Monilinia fructicola. Phytopathology 93, 102–111.

Luvisi, D.A., Shorey, H., Smilanick, J., Thompson, J., Gump, B.H., Knutson, J., 1992.Sulfur dioxide fumigation of table grapes. Univ. Calif. Div. Agric. Nat. Resour.Bull., 1932.

Ma, Z., Luo, Y., Michailides, T.J., 2003. Nested PCR assays for detection of Moniliniafructicola in stone fruit orchards and Botryisphaeria dothidea from pistachios inCalifornia. J. Phytopathol. 151, 312–322.

Ma, Z., Michailides, T.J., 2004. A real-time PCR assay for the detection of azoxystrobin-resistant Alternaria populations from pistachio orchards in California. Crop Prot.23, 1259–1263.

Marois, J.J., Bledsoe, A.M., Gubler, W.D., 1986. Control of Botrytis cinerea on grapeberries during postharvest storage with reduced levels of sulfur dioxide. PlantDis. 79, 1050–1052.

McClellan, W.D., Hewitt, W.B., 1973. Early Botrytis rot of grape: time of infection andlatency of Botrytis cinerea Pers. in Vitis vinifera L. Phytopathology 63, 1151–1157.

Michailides, T.J., Morgan, D.P., 1996. Using incidence of Botrytis cinerea in kiwifruitsepals and receptacles to predict gray mold decay in storage. Plant Dis. 80,248–254.

Mlikota Gabler, F., Smilanick, J.L., Mansour, M., Ramming, D.W., Mackey, B.E., 2003.Correlations of morphological, anatomical, and chemical features of grapeberries with resistance to Botrytis cinerea. Phytopathology 93, 1263–1273.

Nair, N.G., Guilbaud-Oulton, S., Barchia, I., Emmett, R., 1995. Significance of carry-over inoculum, flower infection and latency on the incidence of Botrytis cinereain berries of grapevines at harvest in New South Wales. Aust. J. Exp. Agric. 35,1177–1180.

Nelson, K.E., 1958. Some studies of the action of sulfur dioxide in the control ofBotrytis rot of Tokay grapes. J. Am. Soc. Hortic. Sci. 71, 183–189.

Nelson, K.E., 1985. Harvesting and handling California table grapes for market.University of California Bulletin No. 1913, University of California AgriculturalExperiment Station, Oakland, CA, 72 pp.

Nelson, K.E., Ahmedullah, M., 1972. Effect of type of in-package sulfur dioxide gener-ator and packaging materials on quality of stored table grapes. Am. J. Enol. Vitic.23, 78–85.

Nelson, K.E., Richardson, H.B., 1967. Storage temperature and sulfur dioxide treat-ment in relation to decay and bleaching of stored table grapes. Phytopathology57, 950–955.

Novoa, R., Villaseca, S. (Eds.), 1989. Mapa Climático de Chile. Instituto de Investiga-ciones Agropecuarias, INIA, Santiago, Chile, p. 221.

Peschel, S., Knoche, M., 2005. Characterization of microcracks in the cuticle of devel-oping sweet cherry fruit. J. Am. Soc. Hort. Sci. 103, 487–495.

Pezet, R., Viret, O., Perret, C., Tabacchi, R., 2003. Latency of Botrytis cinerea Prs.: Fr.and biochemical studies during growth and ripening of two grape berry culti-vars, respectively susceptible and resistant to grey mould. J. Phytopathol. 151,

208–214.

Smilanick, J.L., Hartsell, P.I., Henson, D., Fouse, D.C., Assemi, M., Harris, C.M., 1990.Inhibitory activity of sulfur dioxide on the germination of spores of Botrytiscinerea. Phytopathology 80, 217–220.

Smilanick, J.L., Henson, D.J., 1992. Minimum gaseous sulphur dioxide concentrationsand exposure periods to control Botrytis cinerea. Crop Prot. 11, 535–540.

gy an

U

V

V

J.P. Zoffoli et al. / Postharvest Biolo

SDA, 1999. United States standards for grades of table grapes (Europeanor Vinifera type). http://www.ams.usda.gov/standards/stanfrfv.htm, (accessed:October 2008).

alenzuela, J., 2000. Uva de mesa en Chile. J. Valenzuela (Ed). Colec. Libros INIA

No. 5, Instituto de Investigaciones Agropecuarias, Min. Agric., Gobierno de Chile,Santiago, Chile, 338 pp.

alenzuela, J., Lobato, A., 2000. Reguladores de crecimiento, In: Uva demesa en Chile, ed. J. Valenzuela, Colec. Libros INIA No. 5 Institutode Investigaciones Agropecuarias, Min. Agric., Gob. Chile, Santiago, Chile,pp. 179–210.

d Technology 52 (2009) 126–133 133

Viret, O., Keller, M., Jaudzems, V.G., Cole, F.M., 2004. Botrytis cinerea infection of grapeflowers: light and electron microscopical studies of infection sites. Phytopathol-ogy 94, 850–857.

Zoffoli, J.P., 2002. Orientaciones para un manejo eficiente del generador de anhídrido

sulfuroso en el embalaje de uva de mesa. Aconex (Chile) 75, 20–24.

Zoffoli, J.P., Latorre, B.A., Naranjo, P., 2008. Hairline, a postharvest cracking disorderin table grapes induced by sulfur dioxide. Postharvest Biol. Technol. 47, 90–97.

Zoffoli, J.P., Latorre, B.A., Naranjo, P., 2009. Pre-harvest applications of growth regu-lators and their effect on postharvest quality of table grapes during cold storage.Postharvest Biol. Technol. 51, 183–192.