Preharvest applications of growth regulators and their effect on postharvest quality of table grapes during cold storage

Over 54,600 ha of table grapes (Vitis vinifera), mainly cvs. ‘Thompson Seedless’, ‘Flame Seedless’ and ‘Redglobe’, are planted in Chile. Almost the entire production is exported to the USA, Europe, Asia, or one of several Latin American countries, which typically requires 15–40 d of maritime transportation. During this period, several physical, physiological, and pathological factors cause table grape deterioration. Because berry size is the main quality factor in international markets, farmers often overuse the growth regulators, gibberellic acid (GA₃) and forchlorfenuron (CPPU), in an effort to increase berry size. We examined the effect of preharvest growth regulators on seedless (‘Thompson Seedless’, and ‘Ruby Seedless’) and seeded (‘Redglobe’) table grape cultivars during cold (0 °C) storage plus a shelf life period of 3 d at 20 °C. The overuse of GA₃, eight instead of two GA₃ applications on Thompson Seedless, and the use of one GA₃ application on Redglobe and ‘Ruby Seedless’, increased berry pedicel thickness and lowered cuticle content but induced shatter and predisposed grapes to gray mold caused by Botrytis cinerea. In contrast, CPPU increased berry pedicel thickness and cuticle content but did not increase shatter or gray mold incidence. Clusters that were subjected to overuse of combined GA₃ and CPPU were highly sensitive to shatter, had the thickest pedicel, and developed a high gray mold incidence during cold storage. Hairline, a fine cracking developed during cold storage, was induced on ‘Thompson Seedless’ and ‘Ruby Seedless’ by growth regulators, but no hairline occurred on ‘Redglobe’ table grapes. Therefore, berry quality during cold storage is greatly influenced by growth regulator management in the vineyard.     

三个特色无核葡萄品种规范性贮藏保鲜技术

介绍无核白(Thompson Seedless)、克瑞森无核(Crimson Seedless)和火焰无核(Flame seedless)三个特色葡萄品种的果穗果实特征特性及贮运特征特性,提出三个无核品种葡萄的规范性贮藏工艺技术和独特保鲜技术,旨在为我国无核品种葡萄的产业化贮藏保鲜提供技术支持。     

Modified ethanol atmosphere to control decay of table grapes during storage

The efficacy of three methods of applying ethanol to prevent storage decay was tested on two cultivars of table grapes, ‘Superior’ and ‘Thompson Seedless’. Ethanol was applied by: (1) dipping grapes in 50% ethanol for 10 s followed by air drying before packaging; (2) placing a container with a wick and 4 or 8 ml ethanol/kg grapes inside the package; (3) applying 4 or 8 ml ethanol/kg grapes to paper and placing this paper above the grapes in the package. The grapes were stored for 6 or 8 weeks at 0 °C and assessed after an additional 3 days at 20 °C. All methods of application controlled decay as well as or better than a SO₂-releasing pad. The ethanol impregnated paper caused high levels of berry browning, perhaps because of high levels of acetaldehyde inside the package. However, the taste of the berries was not impaired by any of the ethanol applications. The taste of ‘Thompson Seedless’ grapes stored for 8 weeks in modified atmosphere storage was affected by CO₂ levels above 7%. Some methods of applying ethanol used here show promise as alternatives to SO₂ to prevent decay of grapes during storage while maintaining fruit quality.     

葡萄果实结构与耐贮性关系的研究

通过对巨峰、红地球、秋红、秋黑四个品种葡萄果实结构与耐压力、耐拉力关系的研究,发现葡萄浆果耐拉力大小与果柄粗细、果蒂大小以及果刷面积成正相关,与单位面积果柄和果蒂上所承受的浆果自重成负相关,耐压力强弱不仅受果肉质地影响,还与果粒大小有一定关系,与果皮厚度关系不大。果梗发育程度对葡萄耐贮性的影响远远大于果梗占果穗的比重,耐压力与耐拉力之间无明显关系。     

Application of abscisic acid (ABA) at veraison advanced red color development and maintained postharvest quality of ‘Crimson Seedless’ grapes

‘Crimson Seedless’ is a popular table grape cultivar, but in warm-climates, its fruits often fail to develop adequate red color, even after they have been treated with ethephon. Application of abscisic acid (ABA) may improve color more effectively than ethephon, but its potential effects on postharvest quality must be considered before recommending its use on table grapes. Therefore, we compared the postharvest quality attributes of grapes treated preharvest with 250 μL L⁻¹ ethephon, the current industry standard, to that of grapes treated with 150 or 300 μL L⁻¹ ABA, or nontreated. Treatment with either ethephon or 150 μL L⁻¹ ABA allowed grapes to be harvested 10 d before nontreated fruit, and fruits treated with 300 μL L⁻¹ ABA attained marketable quality 30 d before nontreated fruit. Early harvest was possible because the treatments induced more rapid coloring of the grapes, and though total yield was not affected by any plant growth regulator (PGR), all PGRs doubled packable yields by improving the color of the grapes. ABA-treated grapes were characterized by superior appearance both in berries and clusters’ rachises compared to ethephon-treated and control grapes. Other quality attributes such as firmness, berry weight, decay incidence, and shatter remained unaffected among treatments. Therefore, ABA is an effective alternative to ethephon for enhancing the color and maintaining postharvest quality of ‘Crimson Seedless’ grapes.     

秋季喷肥对三种葡萄萌芽及花粉生活力的影响

摘要:通过秋季对无核白、克瑞森和红地球三个葡萄品种进行不同配方叶面肥喷施试验,第二年春季测量三个品种各处理葡萄芽的大小、芽的萌发率和花粉生活力,获得最佳秋季喷肥配方,以期为葡萄优质丰产栽培提供理论依据。结果表明,三个葡萄品种喷肥处理芽纵横径长度和花粉生活力均比对照好。处理4芽横径增幅最大,处理4和处理5花粉生活力高,与CK有显著性差异。三个品种各处理的纵径与花粉生活力有显著相关性。     

Prestorage application of high carbon dioxide combined with controlled atmosphere storage as a dual approach to control Botrytis cinerea in organic ‘Flame Seedless’ and ‘Crimson Seedless’ table grapes

Pre-storage application of 40% CO₂ at 0 °C for 24 or 48 h and controlled atmosphere (12% O₂ + 12% CO₂) storage at 0 °C for up to eight weeks on decay control and quality of organic ‘Flame Seedless’ and ‘Crimson Seedless’ table grapes were studied as a postharvest disease control alternative. To simulate different potential field conditions, these organic treatments were applied to organic-grown grapes that were naturally infected (without inoculation), surface inoculated (berries inoculated by spraying with a conidia suspension), and nesting inoculated (clusters inoculated by placing in the middle an artificially infected berry) with the pathogen Botrytis cinerea, the cause of grape gray mold. Under these three conditions, a 40% CO₂ for 48 h pre-storage treatment followed by controlled atmosphere reduced the gray mold incidence from 22% to 0.6% and from 100% to 7.4% after four and seven weeks, respectively. High CO₂ pre-storage alone limited botrytis incidence in both naturally and artificially infected grapes, but was more effective when combined with CA. These treatments did not affect visual or sensory fruit quality. Exposure to high CO₂ for 24 or 48 h effectively inhibited mycelial growth of B. cinerea in PDA plates incubated at 22 °C for up to 72 h. Conidia germination in PDA plates was reduced ∼60% after 12 h incubation. In vitro studies demonstrated a fungistatic effect, but further studies on the mechanism of action could improve treatment performance. This novel high CO₂ initial fumigation followed by controlled atmosphere during storage or transportation could be a commercially feasible alternative for postharvest handling of organic and conventional table grapes. Our results encourage validating this combined physical treatment in other cultivars and under commercial conditions.     

Moisture loss is the major cause of firmness change during postharvest storage of blueberry

Blueberry softening is known to be influenced by cell wall modifications accompanying ripening but these changes appear to be largely complete by the time of harvest. In this study postharvest storage conditions were controlled so only the extent of water loss varied between treatments. A linear relationship between weight loss and loss of firmness (as assessed by a non-destructive compression test) was demonstrated. This relationship did not hold at very low weight loss, where instead, firming of blueberries during storage was found. Magnetic resonance imaging of berries confirmed significant shrinkage and loss of water in berries which had high weight loss, compared with more subtle effects on sub-epidermal water content in berries with very low weight loss. Treatments which restrict blueberry water loss to below 8% are likely to be beneficial in retaining acceptable berry firmness for up to three weeks’ storage.     

Biocontrol of fungi isolated from sour rot infected table grapes by Saccharomyces and other yeast species

Sour rot is an important disease of grapes caused by an etiologic complex of microorganisms in which filamentous fungi play a key role. Yeasts are used for biocontrol of pathogenic filamentous fungi on fruits. The major objective of this study was to assess in vivo on detached berries the effect of viticultural yeasts on phytopathogenic fungi involved in grape sour rot. Yeasts that were found to be effective in vivo against the fungi were assayed for their possible pathogenicity in humans: growth at 42 °C, pseudohyphal formation, adhesion, and phospholipase and protease activity. A total of 234 yeasts belonging to 14 genera were assayed against the following pathogens: Aspergillus caelatus, Aspergillus carbonarius, Aspergillus terreus, Aspergillus versicolor, Fusarium oxysporum, Penicillium comune, Rhizopus stolonifer and Ulocladium sp. Forty-three (16 Saccharomyces and 27 non-Saccharomyces) showed antagonistic properties against some of the fungi assayed in grapes at 25 °C. Yeast isolates determined as biocontrol agents under in vivo conditions were isolated from fermenting musts (35), viticultural soils (6) and grape berries (2). Twenty biocontrol agents did not show phenotypical characteristics associated with pathogenicity in humans.     

果穗曝光对酿酒葡萄果实品质影响的研究进展

影响葡萄果实品质的因素很多,对于特定的葡萄产区而言,在大气候、小气候、土壤、品种等条件相对一定的前提下,通过改变栽培技术措施来改善果实区域微气候,从而提高果实品质显得尤为重要。简述了果实区域曝光,一项操作简便、高效,且能够实现机械化而备受国内外学者关注的新技术,在提高酿酒葡萄果实品质方面的研究概况,包括对总酚、花色苷、单宁等酚类物质含量、香气成分,尤其是甲氧基吡嗪类物质含量的影响。此外,就果穗曝光处理在调节葡萄产量、降低果穗紧实度从而减少病害发生率等方面进行了总结。以及该技术在我国农村劳动力不断减少,劳动力成本不断攀升,葡萄产业亟需集约化、机械化、简单化的大背景下的应用前景和研究方向进行了简要的分析。     

6个葡萄品种（系）抗旱性比较研究

比较6个主栽或杂交育种常用品种（系）的抗旱性差异,为旱区葡萄栽培品种和抗旱育种亲本选择提供依据。在干旱胁迫下,测定各植株生长量、旱害、叶片水势、电导率及胁迫后根系状况,研究各品种（系）间的抗旱性强弱。结果表明,严重胁迫下,‘弗雷无核’和‘无核白鸡心’生长受重创,旱害严重,电导率变化大,根系生长不良,个别干枯;‘温宿红葡萄’、‘新郁’、‘无核白’表现相对较好,‘SP522’次之。‘温宿红葡萄’、‘新郁’、‘无核白’抗旱性强,‘SP522’次之,‘无核白鸡心’和‘弗雷无核’弱。     

复合盐碱胁迫对鲜食葡萄生理生化指标的影响

为筛选出较耐盐碱的新引鲜食葡萄品种,以10个葡萄品种为材料,研究不同浓度复合盐碱（盆土干重的0.29%、0.58%、0.87%）胁迫30天后葡萄生理生化指标的变化特征,对所有指标进行相关性分析,并采用主成分分析法综合评价其耐盐碱能力。结果表明,随着盐碱浓度的增加,根系活力和叶片相对含水量呈逐渐下降趋势,相对电导率、丙二醛和脯氨酸含量呈逐渐上升趋势,超氧化物歧化酶活性呈先上升后下降或持续上升2种趋势。相关性分析发现,叶片丙二醛含量、根系丙二醛含量、叶片脯氨酸含量三者之间两两极显著正相关,根系超氧化物歧化酶活性与叶片丙二醛含量、叶片超氧化物歧化酶活性显著负相关。主成分分析法提取出特征值大于1的3个主成分,累计贡献率77.99%,最终得出10个葡萄品种耐盐碱性顺序由强到弱依次为‘紫甜无核’‘、黑脆无核’‘、户太8号’‘、早夏无核’‘、丝路红玫瑰’‘、阳光玫瑰’‘、深红玫瑰’‘、夏黑’‘、甜蜜蓝宝石’‘、浪漫红颜’。     

西藏昌都市芒康县盐井葡萄生育期界定及气象条件分析

为更好地推进西藏自治区昌都市芒康县盐井乡葡萄产业长足发展，本研究采取平行观测、数理统计的方法开展盐井葡萄物候期人工观测和所在区域气象要素自动监测，根据所得数据分析葡萄生长的不同阶段对气候条件的适应性，并提出灾害防御对策。结果表明，盐井葡萄一般在3月上旬—下旬开始萌芽，5月上中旬进入开花期，6月下旬—7月上旬进入浆果膨大期，1个多月后葡萄开始转色，10月中旬进入成熟期，10月下旬开始落叶随即进入休眠期。从萌芽到成熟，盐井葡萄约需200天左右。盐井光照条件完全能满足葡萄的正常生长和发育的需要，在芽萌动期间逐日气温大都高于10℃，在开花期日平均气温为16.4～20.6℃，且80%以上的时间大于25℃。浆果膨大期日最高气温平均为21.9～28.0℃，期间风力大，20多天风速都达到10 m/s。从萌芽到坐果期，降水很少，从浆果膨大期开始雨水不断增多，但依旧不能满足葡萄生长发育，必须通过灌溉才能满足。     

葡萄霜霉病田间初始发生相关因素分析

【目的】为明确葡萄霜霉病田间初始发生与孢子囊、气象因素及葡萄品种的关系。【方法】连续6年定点调查了无核红宝石、玫瑰香、蛇龙珠上的葡萄霜霉病初始发生时期,同时利用孢子囊捕捉器捕捉葡萄霜霉病菌孢子囊,并通过农田小型气候站监测田间气象数据,分析温度、湿度、降雨等气象因素与霜霉病初始发生的关系。【结果】结果表明在葡萄霜霉孢子囊发现后10 d左右,田间始见病斑;不同品种葡萄上霜霉病的初始发生时期有所不同：红宝石发病最早,其次为玫瑰香,蛇龙珠发病最晚;葡萄霜霉病的发生与气温、相对湿度、降雨量等气候条件密切相关,其中降雨量是影响葡萄霜霉病初始发生的主导气象因子。【结论】通过对以上数据分析,本研究提出多种直接又简便的预测方法,用于葡萄霜霉病的预防防治。     

葡萄果实单萜生物合成与调控的研究进展

萜烯是一系列以异戊二烯为单元的烯烃类化合物,在葡萄果实中主要以单萜为主,它们具有愉悦的花、果香气味。因为萜烯类物质的阈值很低,所以尽管它们在葡萄果实中的含量不高,依然对葡萄果实与葡萄酒的香气品质有着重要贡献,提高果实单萜含量则成为了葡萄香气育种的主要目标。本研究主要综述了葡萄果实单萜合成途径关键基因-单萜合成酶基因和糖基转移酶基因的研究进展,分析了基因型和气候因素对单萜生物合成的影响,结果发现:不同品种的葡萄果实中,单萜合成路径的关键酶VvGT7以及VvDXS都在关键活性位点存在氨基酸种类的差异,且已经证实这种差异会导致萜烯含量的不同;光照、水分以及温度等环境因素的差异都是导致葡萄果实中萜烯含量不同的原因。最后对单萜在转录水平上的调控研究进行了展望。     

Effects of selection on early stage genetic evaluation for berry weight in breeding table grapes

The effects of random and directional selection on estimates of heritability and estimated breeding values were investigated using data collected for grape berry weight during seasons 1999 and 2000 from the CSIRO table grape breeding population. In 1999, all berry‐bearing vines available (4834) were assessed, while in 2000 a randomly selected sample of 1344 vines was evaluated. In addition, a simulated directional selection was imposed such that the berry weights for half of the vines with lighter berries sampled in 2000 were discarded to produce a biased data set. The results showed that heritability of berry weight in 2000 was biased downward and estimated breeding values were over‐ or under‐estimated if analyses were based on directionally selected data sets alone. By incorporating data from 1999 into bivariate analyses, bias in heritability and EBV could be eliminated to a large extent. The implications for grapevine breeding are discussed.     

Integration of continuous biofumigation with Muscodor albus with pre-cooling fumigation with ozone or sulfur dioxide to control postharvest gray mold of table grapes

An integrated approach was evaluated that combined biological and chemical fumigation of table grapes to control postharvest gray mold caused by Botrytis cinerea. After fumigation of the grapes with ozone or sulfur dioxide during pre-cooling, the fruit were then exposed to continuous biofumigation by the volatile-producing fungus Muscodor albus during storage. Biofumigation was provided by in-package generators containing a live grain culture of the fungus. This grain formulation of M. albus survived the initial ozone or sulfur dioxide fumigation, but sulfur dioxide reduced its production of isobutyric acid, an indicator of the production of antifungal volatiles. Gray mold incidence was reduced among inoculated ‘Autumn Seedless’ grapes from 91.7 to 19.3% by 1 h fumigation with 5000 μL L^?1 ozone, and further reduced to 10.0% when ozone fumigation and M. albus biofumigation were combined. The natural incidence of gray mold among organically grown ‘Thompson Seedless’ grapes after 1 month of storage at 0.5 °C was 31.0%. Ozone fumigation and M. albus biofumigation reduced the incidence of gray mold to 9.7 and 4.4, respectively, while the combined treatment reduced gray mold incidence to 3.4%. The use of commercial sulfur dioxide pads reduced the incidence to 1.1%. The combination of ozone and M. albus controlled decay significantly, but was less effective than the standard sulfur dioxide treatments. Although less effective than sulfur dioxide treatment, ozone and M. albus controlled decay significantly, and could be alternatives to sulfur dioxide, particularly for growers complying with organic production requirements.     

Postharvest treatment of polyamines maintains quality and extends shelf-life of table grapes (Vitis vinifera L.) cv. Flame Seedless

Investigations were carried out to verify the potential of putrescine and spermidine as a postharvest dip treatment for maintaining quality and extending storage life of table grapes (Vitis vinifera L.) cv. Flame Seedless during the 2012 and 2013 seasons. Grape clusters were manually harvested at the commercial mature stage and were dipped in different concentrations (0.0, 0.5, 1.0 and 1.5 mM) of putrescine and spermidine, and then stored at 3–4 °C, and 90–95% RH. Evaluation of physico-chemical parameters and other fruit quality attributes were made at 0 day (before treatment) and at 30, 45, 60 and 75 days of storage. Putrescine and spermidine at the lowest dose (0.5 mM) effectively maintained berry firmness, peel colour (L*, C*, h°) and stabilized anthocyanins as well as suppressing the activity of pectin methylesterase and reducing the rate of electrolyte leakage. The polyamines also retarded the degradation of TSS and TA while maintaining higher total phenol content and reduced decay incidence. Putrescine and spermidine at 1.0 mM exhibited almost similar effects with a 0.5 mM dose. The highest doses (1.5 mM) of both polyamines showed detrimental effects, especially on weight loss, decay incidence, rachis browning and organoleptic properties, as found in the control group, which was commercially acceptable only up to 45 days. Furthermore, analysis of linear regressions and correlations showed that many quality parameters were interdependent. The postharvest dip treatment of spermidine or putrescine at a dose of 0.5 mM for 5 min could be an effective means for prolonging storage and increasing shelf-life of ‘Flame Seedless’ grapes.