Dynamics of anthocyanin and flavonol profiles in the ‘Crimson Seedless’ grape berry skin during development and ripening

‘Crimson Seedless’ grapes (Vitis vinifera L.) do not develop adequate berry colour in different parts of the world including Australia and USA leading to serious economic losses to the growers. In the present study, various anthocyanins and flavonols were identified in the skin of the ‘Crimson Seedless’ grape berries using LC/PDA/ESI-MS and their changes in the berry skin during development and ripening of ‘Crimson Seedless’ grape berries were investigated during 2005–2006 and 2006–2007. Eleven anthocyanins and two flavonols were identified in the berry skin using LC/PDA/ESI-MS. Of the anthocyanins identified, four anthocyanins including cyanidin 3-O-(6″-O-acetyl)-glucoside, peonidin 3-O-(6″-O-acetyl)-glucoside, malvidin 3-O-(6″-O-acetyl)-glucoside and malvidin 3-O-(6″-O-coumaroyl)-glucoside were not reported earlier. During both the years, the concentration of the 3-O-glucosides of delphinidin, petunidin, peonidin, and malvidin as well as the acetyl and coumaroyl esters of the 3-O-glucosides of cyanidin, peonidin, and malvidin in the berry skin increased during berry development and ripening. During 2006–2007, the concentration of cyanidin 3-O-glucoside in the berry skin increased during the early stages of berry ripening and subsequently declined till harvest while in 2005–2006, the concentration increased during the initial phase of berry ripening and remained relatively stable thereafter till harvest. The concentration of total anthocyanins in the berry skin was higher during 2006–2007 as compared to 2005–2006. During both years, the concentration of quercetin 3-O-glucoside in the berry skin increased during berry development and ripening while the concentration of quercetin 3-O-glucuronide in the berry skin decreased during the same period. To the best of our knowledge, this is the first report on the evolution of different anthocyanins and flavonols in the ‘Crimson Seedless’ berry skin during berry development and ripening.     

Berberis buxifolia fruiting: Kinetic growth behavior and evolution of chemical properties during the fruiting period and different growing seasons

This work studied the growth of Berberis buxifolia fruits and some of their chemical attributes during the fruiting period and different growing seasons (2004/2005, 2005/2006, 2006/2007) from November (14 days from full flower phase) till March (126 days from full flower phase) for plants growing in a natural environment near Ushuaia city (Tierra del Fuego, Argentina). B. buxifolia fruit growth and composition presented significant changes during the fruiting period and the studied growing seasons. Fresh and dry weight of B. buxifolia fruits exhibited a typical double sigmoid curve. The first period of rapid growth was from full flower phase till 42–56 days after, while the second phase of rapid growth began around the 56–70 days from full flower and ended approximately 4 months later. On a dry weight basis the maximum fruit biomass (119.5 mg) was reached 112 days after full flower while maximum fresh weight fruit biomass (424.3 mg) occurred by day 84. Evolution of fruit growth was related with the compositional changes evaluated. By day 126 from full flower, soluble solids (24.9°Brix) and anthocyanin concentration (761.3 mg/100 g fruit fresh weight) were at their maximum values, while at this time the total titratable acidity was at a minimum value (2.56%). The results obtained not only contributes to the knowledge of the quantitative content of anthocyanin, a metabolite with nutraceutical value but, gives some tools for the definition of the optimal harvest time of B. buxifolia fruits, what it is important for fruit destination.     

不同土壤条件对酿酒葡萄生理及果实品质的影响

【目的】为了探索不同土壤条件对酿酒葡萄生理及果实品质的影响,【方法】以‘蛇龙珠’酿酒葡萄为试材,研究了宁夏贺兰山东麓地区,黄河淤土、含石的沙壤土和风沙土3种土壤对葡萄糖分卸载的影响,测定了不同土壤栽培条件下葡萄果实的单果质量、可溶性固形物、可滴定酸、可溶性总糖、色素、单宁及葡萄叶片的光合速率。【结果】结果表明,在葡萄开始着色至葡萄完全成熟期间,在含石的沙壤土栽培条件下葡萄可溶性总糖含量(22.4%)比黄河淤土栽培条件下和风沙土栽培条件下分别高7%、9%;葡萄色素(5.14 mg.g-1)和叶片光合速率也最高,黄河淤土栽培条件下葡萄的含酸量(8.28 g.L-1)和单粒质量(2.32 g)较高,然而,风沙土条件下,单宁(籽单宁1.15 mg.g-1,皮单宁0.30 mg.g-1)的含量最高。【结论】土壤条件对酿酒葡萄果实品质影响较为显著,含石的沙壤土条件下葡萄品质最佳。     

毛欧杂种葡萄‘NW196’花色苷组成与相关基因表达分析

以不同发育期毛欧杂种葡萄‘NW196’为试验材料,利用HPLC–MS检测其果皮中花色苷的组成及含量,Real-time PCR检测花色苷合成相关基因表达水平,并与欧亚种‘赤霞珠’比较。结果表明,成熟后期‘NW196’果皮中花色苷总量显著高于‘赤霞珠’;采收期‘NW196’葡萄果皮中共检测到23种花色苷,成熟后期单糖苷所占比例高于双糖苷,其中含量最高的是花翠素–3–O–葡萄糖苷,3’5’–羟基取代花色苷比例高于3’–羟基取代花色苷;与欧亚种‘赤霞珠’相比,‘NW196’果皮中酰化和甲基化花色苷比例较低。结论:毛欧杂种‘NW196’花色苷组成与欧亚种‘赤霞珠’差异明显,这与其品种特性有关,并受到类黄酮代谢路径相关基因的调控;此外,花色素双糖苷主要在转色初期合成。     

成膜型抗蒸腾剂对‘赤霞珠’葡萄成熟进程的影响

为探讨成膜型抗蒸腾剂对酿酒葡萄成熟进程的影响机理,以酿酒葡萄品种‘赤霞珠’为试材,在始熟期前(花后55 d)对果实定期喷施3次成膜型抗蒸腾剂Vapor Gard(有效成分为帖烯聚合物松脂二烯),对照喷施清水。成膜型抗蒸腾剂处理对成熟初期葡萄果粒横、纵径及百粒质量影响不显著,但降低果实还原糖、可溶性固形物及总酚积累量,提高果实含酸量。成膜型抗蒸腾剂处理延缓了始熟期果实膨压的下降及果实转色,通过下调果实花色苷合成通路中关键基因MYBA、OMT、UFGT的表达降低了成熟初期果实总花色苷含量及修饰类花色苷在总花色苷中所占的比例。因此推测成膜型抗蒸腾剂处理可能通过减少果实水分蒸腾来保持果实的膨压,从而延迟果实转色和成熟进程,因而此抗蒸腾剂可被用来调节葡萄果实的发育进程。     

不同高度结果部位对酿酒葡萄果实品质的影响

以泾阳县主栽的酿酒葡萄赤霞珠和北醇为试材,研究了距地面40、801、20 cm结果部位成熟果实的糖、酸、总酚、单宁及花色素苷含量。结果表明:赤霞珠和北淳在结果部位高度距地面80 cm时,葡萄果实中的还原糖、单宁、总酚及总花色素苷含量均显著高于40 cm及120 cm。单宁和总酚含量在80 cm部位高度表现最高。说明,结果部位过高或过低均不利于葡萄果实中糖分和酚类物质的积累及果实中酸的条件。综合比较,在陕西泾阳,赤霞珠和北醇均以80 cm结果部位的果实品质最好。     

Delayed harvest improves red blush development and quality of ‘Cripps Pink’ apple

The poor red blush development on ‘Cripps Pink’ (Malus x domestica Borkh.) apple fruit at commercial maturity (CM) reduces the economic return to apple growers in warmer regions of the world. The effects of delayed harvest maturity up to 6 weeks following CM on the development of red blush and fruit quality of ‘Cripps Pink’ apple were investigated at two locations in Western Australia during 2003 and 2004. The red blush, export-grade fruit, total anthocyanin, cyanidin 3-galactoside, chlorogenic acid, catechin, and epicatechin of apple fruit skin tissues increased with advancement of harvest maturity at both locations in both years, whereas hue angle, concentration of phloridzin, fruit firmness, and titratable acidity (TA) of apple fruit tissues decreased with delayed harvest. The internal ethylene concentration was elevated with the delayed harvest. The concentrations of quercetin 3-galactoside, quercetin 3-arabinoside, quercetin 3-rutinoside, quercetin 3-rhamnoside, and quercetin 3-glucoside increased up to 2 weeks following CM, and then declined in 2003 at both locations and at Perth Hills in 2004. Delayed harvest resulted in improved development of red blush on the fruit surface, accumulation of total anthocyanin, cyanidin 3-galactoside, chlorogenic acid, catechin, epicatechin, and quercetin glycosides in fruit skin, SSC:TA ratio and reduced fruit firmness possibly due to the increased ethylene production.     

Application timing and concentration of abscisic acid affect the quality of ‘Redglobe’ grapes

Summary

The plant hormone abscisic acid (ABA), the concentration of which increases in grape berry skins at the onset of maturation (veraison), appears to be involved in the regulation of anthocyanin accumulation. Preliminary tests suggested that exogenous applications of ABA could improve grape berry colour, but its high cost precluded the development of commercial applications. Recently, a lower-cost ABA production method was developed, which led to the evaluation of different concentrations of ABA, applied at or around veraison, on the quality of ‘Redglobe’ grapes. In two of three years of tests, several ABA treatments enhanced the anthocyanin content of grape skins. ABA, applied at approx. 300 mg l^–1 at veraison, may be required to reliably increase pigmentation, and improve the colour of ‘Redglobe’ grapes. Although the total anthocyanin content was increased by ABA treatment, anthocyanin composition was not affected. Applications of ABA had few effects on fruit size or composition, although they did cause fruit softening, which is undesirable. A secondary objective of this study was to determine how the anthocyanin content of berry skins affected berry colour characteristics. Strong curvilinear relationships between anthocyanin content and lightness and hue showed that these colour characteristics were saturated by anthocyanin contents over 0.02 mg cm^–2 of skin. These data suggest that colour measurements may be needed to evaluate the effect of cultural practices on colour in table grapes.     

Improving yield,quality, and shelf life of Thompson seedless grapevine by preharvest foliar applications

Ten-year-old Thompson seedless grape vines were sprayed during 2009 and 2010 growing seasons with putrescine (Put), gibberellic acid (GA₃), ascorbic acid (AA), ethephon (Eth), salicylic acid (SA), cytofex (CPPU) and calcium chloride (CaCl₂) at two stages of berry development; pea stage (4–5 mm fruitlet diameter, ∼30–35 days after fruit set) and veraison stage (when approximately 20% of the berries on 50% of the clusters had softened) in order to investigate their influence on yield and postharvest fruit quality characters at commercial harvest day as well as the berry keeping quality. Cluster and berry quality characters as well as vine yield were improved by all sprayed chemicals, especially Put, GA₃, SA, CPPU and CaCl₂. GA₃ increased cluster and berry width, and resulted in better clusters shape. A positive increase in berry firmness was obtained by Put, GA₃, CPPU, SA and CaCl₂ sprays. Berry adherence strength increased and the percentage of unmarketable berries decreased by all sprayed compounds except Eth. Shelf life (keeping quality) was increased by spraying Put, GA₃, SA, CPPU and CaCl₂, as they increased berries firmness and decreased the percentage of unmarketable berries after keeping at ambient temperature for seven days after harvest.     

油菜素内酯和脱落酸调控葡萄果实花色苷合成的研究

【目的】为研究2,4-表油菜素内酯(2,4-epibrassinolide,EBR)和脱落酸(abscisic acid,ABA)处理对葡萄花色苷合成与可溶性固形物含量、果皮苯丙氨酸解氨酶(PAL)和类黄酮糖基转移酶(UFGT)活性以及果实内源ABA含量的影响,探索油菜素内酯调控葡萄果实成熟及花色苷合成的机理。【方法】以酿酒葡萄‘赤霞珠’(Cabernet Sauvignon)和‘烟73’(Yan 73)为试材,在葡萄转色前分别用0.1、0.4、0.8 mg.L-1EBR,1mg.L-1Brz(brassinazole,BR生物合成抑制剂)和200 mg.L-1ABA,均匀喷施于葡萄果实,在葡萄成熟过程中测定葡萄果皮花色苷含量及PAL和UFGT酶活性,同时测定果实ABA和可溶性固形物含量。【结果】在果实着色初期,‘赤霞珠’和‘烟73’葡萄果皮PAL和UFGT活性及果实内源ABA含量均逐渐升高,当果实接近成熟花色苷含量基本稳定时ABA含量开始降低。与对照相比,0.4mg.L-1EBR和200 mg.L-1ABA处理显著增加了果实内源ABA含量,提高了果皮PAL和UFGT活性,促进了果皮花色苷的合成和果实可溶性固形物的积累。0.1 mg.L-1和0.8 mg.L-1EBR处理总体增加了果实内源ABA含量,促进了花色苷的合成和可溶性固形物的积累,并提高了UFGT和PAL酶活性,但比0.4 mg.L-1EBR处理提高的幅度小,且差异显著。1 mg.L-1Brz处理使果实ABA的合成推迟,果实可溶性固形物含量、果皮PAL和UFGT活性以及花色苷含量均低于对照,但差异不显著。【结论】外源EBR和ABA处理促进了葡萄成熟和花色苷合成,在不同浓度EBR处理中,以0.4 mg.L-1处理效果较好;内源ABA可能参与了EBR对葡萄成熟和花色苷合成的调控。     

Changes in fruit quality in black chokeberry (Aronia melanocarpa) during maturation

Summary

Black chokeberry fruits are rich in anthocyanins and can be used as a raw material for the production of natural food colourants. Fruit quality was studied during maturation in three true black chokeberry cultivars and in three cultivars derived through hybridization between chokeberry and rowans (Sorbus spp.). For each trait studied, the three black chokeberry cultivars were very similar. The three hybrid cultivars differed however from the black chokeberry cultivars for some traits in both timing and size of the response which indicates that cultivar selection for improvement of fruit quality can hardly be done among the true black chokeberry genotypes but may be efficient when the hybrid cultivars are also included. For the black chokeberry cultivars, maximum berry weight was reached already by the 22 August. Anthocyanin content increased by 180% during the period mid-August to mid-September. Meanwhile, the content of undesirable brown compounds increased by 100%. The content of malic acid remained unchanged whereas total acidity decreased in the initial part of the study period. Variation among sampling dates in total acidity was negatively correlated with variation in berry weight which suggests that dilution by water uptake affects total acidity. For the true black chokeberry cultivars, optimal harvest date was determined to be 8 September for this trial, when both mean berry weight and anthocyanin content had reached their maximum. By harvesting one week earlier browning was reduced by 32% but with a simultaneous decrease in anthocyanin content of 20%.     

Fruit quality in ‘Cripp's Pink’ apple,especially colour,as affected by preharvest sprays of aminoethoxyvinylglycine and ethephon

‘Cripp's Pink’ apple grown in Western Australia often develops poor colour at commercial harvest resulting in economic losses. To determine if fruit colour could be improved without advancing ripening, ‘Cripp's Pink’ apple fruit on trees were sprayed with aminoethoxyvinylglycine (AVG) alone, ethephon alone, or AVG followed by ethephon. The experiments were conducted at two different locations in Western Australia in 2002 and 2003. Fruit sprayed with AVG alone had retarded colour development at harvest. However, ethephon applied after AVG enhanced percent red blush, anthocyanin concentration and reduced chlorophyll concentration in the fruit skin in both locations. These fruit had similar colour to those treated with ethephon alone. Internal ethylene concentration and fruit firmness were unaffected by the different treatments in 2002. However, in 2003 AVG with or without ethephon reduced internal ethylene concentration and maintained firmness compared to ethephon alone. In conclusion, AVG treatment alone delayed colour development and ripening of ‘Cripp's Pink’, while AVG application 5 weeks before harvest followed by an ethephon application 2 weeks later enhanced red colour at commercial harvest. This is, therefore, an effective tool for improving colour of ‘Cripp's Pink’ apples at commercial harvest without adversely affecting other fruit quality attributes.     

成熟期土壤含水量对‘北玫’葡萄果实中酚类物质积累的影响

以‘北玫’葡萄为试材,采用HPLC法测定葡萄果实中单体酚类物质的含量,研究了成熟期不同土壤含水量处理对果实品质和酚类物质含量的影响,以期为贺兰山东麓酿酒葡萄产区酿酒葡萄品质的提高提供参考依据。结果表明:降低土壤含水量处理可以提高果实中可溶性总糖含量,降低可滴定酸含量。50%~60%相对土壤含水量处理极显著提高了采收期果实中甲基花青素、花翠素葡萄糖苷的含量,显著提高了二甲花翠素的含量;总花色苷和单宁含量极显著高于CK,总酚含量也显著高于CK。对采收期果实中酚类物质指标进行主成分分析,50%~60%相对土壤含水量处理综合得分最高。     

Harvest and post-harvest apple fruit quality following applications of kaolin particle film in South African orchards

Sunburn on apples in the Western Cape region of South Africa can result in yield losses of up to 50%. Application of kaolin-based particle film (Surround^® WP) increases leaf and fruit surface reflectivity, thus potentially reducing heat load and sunburn. Trials were performed during 2002/2003 and 2003/2004 to assess the effectiveness of kaolin particle film in controlling sunburn on ‘Granny Smith’, ‘Braeburn’, ‘Fuji’, ‘Royal Gala’ and ‘Cripps’ Pink’ apples. Fruit quality and ripening were monitored following 1–4 months in regular atmosphere cold storage at −0.5 °C. Sunburn on exposed fruit was significantly reduced in ‘Granny Smith’ and ‘Fuji’. Kaolin treatment improved fruit colour of ‘Granny Smith’ and ‘Royal Gala’, and delayed starch conversion in ‘Granny Smith’ at harvest and during the early storage period but not thereafter. Incidence of watercore at harvest was significantly reduced by kaolin treatment, but this disorder disappeared during cold storage in both treatments. There were no effects on skin anthocyanin or phenolic concentrations in any cultivar compared to unsprayed fruit.     

外源6-BA对‘美乐’葡萄花色苷合成的影响

【目的】探究6-BA对葡萄花色苷合成的影响。【方法】以酿酒葡萄’美乐’为试材,喷施不同浓度的6-BA,以喷施清水为对照,研究6-BA对花色苷含量、组分及其生物合成途径相关基因表达的影响。【结果】100和200 mg·L^-16-BA处理提高了果实着色百分率和内源激素ABA的含量,其中200 mg·L^-1处理促进了花青素的积累,其含量是对照组的4.82倍,相关性分析表明200 mg·L^-1处理组的蔗糖与花色苷含量呈显著正相关。100和200 mg·L^-16-BA处理组的葡萄果实CHS1、F3’H、F3’5’H和UFGT基因的表达量在花后90 d显著提高,6-BA处理组通过影响F3’H和F3’5’H基因的表达量来影响不同花色苷的含量,从而影响果皮色泽。【结论】在果实着色后期,低质量浓度的6-BA通过提高内源激素ABA、可溶性总糖的含量以及相关基因的表达量,促进了花色苷的积累,其中200 mg·L^-16-BA处理效果更佳。     

5–氨基乙酰丙酸促进桃果皮提前着色机制研究

 在‘早白花’桃果实着色前,用300、100和50 mg · L^-1的5–氨基乙酰丙酸（5-aminolevulinic acid,ALA）溶液涂布果实。结果表明：ALA处理可促进果皮提前着色,促使果实提前成熟,且以300 mg · L^-1效果最为明显,比对照早约5 d。ALA处理还显著促进了UFGT、DFR、LDOX和CHS的提前表达,并且基因表达水平与花色素苷的积累趋势具有很好的一致性。据此推测ALA可能参与了桃果实成熟以及花色素苷合成的调控,对果皮花色素苷提前合成具有促进作用。     

Physico-chemical changes during growth of persimmon fruits in the East Mediterranean climate region

Physico-chemical changes were monitored during growth of pollination variant non-astringent ‘Harbiye’ persimmon fruits (Diospyros kaki L.) grown at low or high altitude of the East Mediterranean Region of Turkey for two growing seasons (2001–2002 and 2002–2003). Fruit growth in diameter followed a typical double sigmoid curve, consisting of two rapid growth stages, stage I and stage III, separated by a period of slow growth (stage II) at both altitudes. The durations of stages I, II and III were 105–119, 21–35 and 21–42 days, respectively, at low and high altitude. ‘Harbiye’ persimmons showed significant decreases in soluble tannin concentration and total carotenoid content during stage I. At the end of stage I, ‘Harbiye’ persimmons became non-astringent. Stage II was characterized with slow growth, the beginning of acid degradation and a significant increase in total sugars, especially in the sucrose component. At end of stage II, the fruit began to turn yellow-orange, indicating the occurrence of colour break. The greatest increase in total soluble solids (TSS) content occurred in the final month before harvest during stage III when pronounced changes in skin colour and softening of fruits were observed. The 175 and 168 days after full bloom (DAFB) at low and high altitudes, respectively, are appropriate timing for harvest of the ‘Harbiye’ persimmon fruits in the East Mediterranean region. At these stages, ‘Harbiye’ persimmon fruits reached the best quality for consumers.     

Fruit growth and chemical properties of Ribes magellanicum “parrilla”

The aim of this work was to study the time course and pattern of fruit growth and the evolution of some of the chemical attributes such as soluble solids, acidity, and anthocyanin content in Ribes magellanicum plants growing in a natural environment near Ushuaia city, Tierra del Fuego (Argentina). Fruit growth and composition presented significant changes along the days from the full bloom phase. Fresh and dry fruit weight exhibited a typical double sigmoid curve. The first period of rapid fresh fruit growth was from full bloom phase until 28 days after, followed by a lag period until 42 days from the full bloom phase, and then by a second period of rapid increase until 56 days from the full bloom phase. Then, fresh fruit weight increased slowly (days 70–98 from the full bloom phase), reaching its maximum. Afterwards, fresh fruit weight decreased significantly until the end of the summer, and the fruiting period approximately ended 112 days from full bloom phase. On a dry weight basis the maximum fruit biomass was reached 98 days from the full bloom phase. Evolution of fruit growth was related with the compositional changes evaluated. By day 98 from the full bloom phase, soluble solids (17.5°Brix) and anthocyanin content (240.1 mg/100 g fruit fresh weight) were at their maximum, while at this time the total titratable acidity was at a minimum (0.4%). The results obtained not only contribute to the knowledge of the quantitative content of anthocyanin, a metabolite with nutraceutical value, but also give some tools for the definition of the optimal harvest time of R. magellanicum fruits, which it is important for fruit destination.     

Effects of fruit bagging on coloring and related physiology,and qualities of red Chinese sand pears during fruit maturation

Red Chinese sand pears (Pyrus pyrifolia Nakai) are particular to China. In order to determine the effects of fruit bagging treatments (including bag types, bag removal patterns and dates) on fruit qualities and to understand the mechanism of coloring of red Chinese sand pears, two experiments were carried out. In the first experiment, fruit of ‘Meirensu’ were firstly covered by light-impermeable paper bags with different levels of light permeable liners during their early development stage, then, the whole bag were/not removed or only the outer layer of bags were removed 3, 2 or 1 weeks before harvest. Thus, the fruit were/not totally re-exposed or were under different levels of sunlight transmission (80.31% or 34.71%). Non-bagged fruit were used as the control. Bagging treatments significantly affected the concentration of anthocyanin and the visual qualities of pear fruit. Compared to control, fruit re-exposed totally for 2 or 3 weeks accumulated the largest amount of anthocyanin and fruit receiving 80.31% and 34.71% of sunlight for 1–3 weeks could synthesize a little anthocyanin, indicating that high light intensity is imperative for coloring in red Chinese sand pears. Bagging treatments did not affect contents of total soluble sugars, but decreased organic acids contents in fruit. In the second experiment, fruit of ‘Meirensu’ and ‘Yunhongli No. 1’ were covered with only one type of light-impermeable bag during the early development stage and totally re-exposed after the bag removal 15 days before harvest. Fruit were then collected at different intervals to trace the time-course of coloring, and related physiology and inner qualities. With increasing time after the bag removal, the concentration of chlorophyll, carotenoid, flavonoid and total phenols changed little, but the concentration of anthocyanin accumulated extremely fast within 10 days after the bag removal in both cultivars and thereafter kept constant. ‘Yunhongli No. 1’ had higher anthocyanin contents and lower hue angle than ‘Meirensu’, indicating a higher potential of anthocyanin synthesis. After the bag removal, the sucrose contents and PAL activities increased gradually and correlation analysis revealed that they were highly correlated with anthocyanin accumulation in two cultivars. This study suggests that anthocyanin biosynthesis in red Chinese sand pears is a highly light dependent process and modified by genotypes. Based on the current results, in order to obtain red Chinese sand pear fruit with attractive appearance and good inner qualities, fruit must be covered with light-impermeable bags at the early stage of fruit development and the bag should be removed totally at least 10 days before harvest.     

Partial rootzone drying maintains fruit quality of ‘Golden Delicious’ apples at harvest and postharvest

Partial rootzone drying (PRD) has been evaluated at harvest, but its effects on apple fruit postharvest life is little known for apples grown in semi-arid regions. The objective of this study was to test the hypothesis that water savings via PRD may affect fruit quality at harvest and postharvest-life of ‘Golden Delicious’ apples grown in a semi-arid region. The experiment was conducted from 2005 to 2007. The irrigation treatments were commercial irrigation as control (CI) and PRD. After 3 years of evaluation, fruit quality at harvest, measured as fruit weight, flesh firmness, and total soluble solids concentration, was similar between CI fruit and PRD fruit. Dry matter concentration (DMC) was higher in PRD fruit than in CI fruit in 2005. The fruit quality after 18 days storage at room temperature (13–18 °C and 51–56% relative humidity) was similar between CI fruit and PRD fruit. The DMC was the highest in PRD fruit in the 2005 and 2007 growing seasons, and tended to be higher in PRD fruit than in CI fruit in 2006. Total soluble solids concentration was ≈8.7% higher in PRD fruit than in CI fruit in 2007. Fruit weight loss was similar between treatments. This study suggests that water deficit via PRD did not damage fruit quality at harvest or after storage at room temperature. Additionally, PRD irrigation saved about 3240 m³ of water per hectare. Therefore, PRD can be recommended for commercial use in semi-arid regions and to those growers interested in either long-term storage or distant markets.