Seedless Table Grape Research Articles

The Effects of Some Exogenous Applications on Quality in ‘Crimson Seedless’ Grape

‘Crimson Seedless’ is a red seedless table grape (Vitis vinifera) and although it is widely cultivated in Aegean Region, it does not develop adequate color in warm climate. The present study was carried out to estimate the effect of abscisic acid (S-ABA), ethephon and girdling on color of bunches and metabolic profile on ‘Crimson Seedless’ grapevine variety. To achieve this goal, experimental treatments were carried out during two successive seasons (2017–2018). Experimental materials were eight-year-old ‘Crimson Seedless’ grapevines grafted onto 1103P (V. berlandieri x V. rupestris) of similar vigor and grown in a loamy soil structure under drip irrigation system. In this study a randomized block experimental design with three replications was used, with each plot consisting of six grapevines. Exogenous plant growth regulator (PGR) like S‑ABA and Ethephon was applied to the plant materials in five different application method. T4 (S-ABA+ Ethephon) application for ‘Crimson Seedless’ grape among different applications yielded more effective results on maturity index (SS/TA), total soluble solids (°Brix), a*, CIRG (Color Index of Red Grapes) and cluster lenght (mm) properties than other applications. Exogenous S‑ABA+ Ethephon promoted color development in ‘Crimson Seedless’ grape berries. For this reason, it has been determined that T4 (S-ABA+ Ethephon) treatment gives the best results for “Crimson Seeddless” grape variety. These results indicate that ‘Crimson Seedless’ grapevines grown in a warm climate, where color development is poor, would benefit from a spray of 400 mg/L S‑ABA, ten days after the veraison and 500 mg/L Ethephon, ten days after the first S‑ABA application.

Phenotypic and genetic study of seedlessness in grape varieties

The phenomenon of seedlessness in grapes is a special form of sterility and it is characterized by the complete absence of seeds in the berry or the presence of their primordia. A phenotypic and genetic studies of 20 varieties of seedless grape growing at the Anapa ampelographic collection were carried out. The manifestation of the degree of seedlessness may depend on growing conditions and climatic peculiarities during crop formation. In the weather and climate conditions of 2019, which were characterized by an increased temperature regime, the degree of seedless berries of the studied varieties was determined. Genetic studies were performed on the basis of polymerase chain reaction (PCR) with the separation of reaction products by capillary electrophoresis using the automatic genetic analyzer ABI Prism 3130. The DNA-marker p3-VvAGL11, closely linked to the VvAGL11 locus, which influences to the formation of seedlessness in grapes, was used in the work. The mass of rudiments was determined by extracting seed primordia from berries and their dehydration in a drying cabinet to final unchanged mass of rudiments. In the varieties Kishmish Sogdiana, Remaily Seedless and Kishmish Kruglyi rudiments were practically absent. The greatest mass of rudiments in the berry (over 14.1 mg) was observed in the varieties Pamyati Smirnova, Yangi Yer, Vanessa Seedless, Kishmish Luchistyi. In addition to the degree of development of seed rudiments, in seedless table grape varieties, an important indicator is the size of the berry, which generally affects the consumer choice of a particular variety. By the average weight of the berry, Kishmish Luchistyi variety (5.05 g) was distinguished. The smallest mass of berries observed in varieties Rozovyi Biser, Kishmish Siyekh, Kishmish Kruglyi, Kishmish Krupnyi, Bessemyannyi Ranniy (less than 1.5 g). DNA analysis using the p3-VvAGL11 marker revealed in all genotypes the presence of a PCR-product with a size of 198 nucleotide pairs, which corresponds to published data on the correlation of this size of the PCR-product with seedless berries.

Cover Crops Affect Performance of Organic Scarlotta Seedless Table Grapes Under Plastic Film Covering in Southern Italy

In sustainable or organic vineyard systems, the introduction of cover crops could represent a powerful tool for farmers to influence, positively, the agro-ecosystem by promoting the whole soil-plant system equilibrium. Concerning table grape production, nitrogen fertilizers are medium-high; for environmental aspects, organic viticulturists are more interested in legume inter-row cover crops. Research on cover crop effects was carried out in 2015–2016, on organic table grapes (the Sugranineteen variety) in Mediterranean conditions. Three inter-row soil management techniques were compared: (TR) inter-row spacing was cultivated with subterranean clover; (V) inter-row spacing with common vetch incorporated in the soil as green manure, and (RC) inter-row spacing with common vetch flattened by the roller crimper technique, making a living mulch. No significant difference was recorded in grapevine water status among the treatments. RC vines performed the highest net photosynthesis rate from shoot growth to veràison. Cover crops did not affect cluster weight, berry weight, and juice composition; however, they influenced berry detachment force. Our research findings confirmed that legume cover crops (subterranean clover and common vetch) increased soil organic matter and could represent an economic and sustainable soil use to reduce the amount of nitrogen fertilizers applied in table grape production.

Fluorescence-Sensor Mapping for the in Vineyard Non-Destructive Assessment of Crimson Seedless Table Grape Quality.

Non-destructive tools for the in situ evaluation of vine fruit quality and vineyard management can improve the market value of table grape. We proposed a new approach based on a portable fluorescence sensor to map the ripening level of Crimson Seedless table grape in five different plots in the East, Central-North and South of the Macedonia Region of Greece. The sensor provided indices of ripening and color such as SFRR and ANTHRG correlated to the chlorophyll and anthocyanin berry contents, respectively. The mean ANTHRG index was significantly different among all the plots examined due to the occurrence of different environmental conditions and/or asynchronous ripening processes. The indices presented moderate, poor in some cases, spatial variability, probably due to a significant vine-to-vine, intra-vine and intra-bunch variability. The cluster analysis was applied to the plot with the most evident spatial structure (at Kilkis). Krigged maps of the SFRR, ANTHRG and yield were classified by k-means clustering in two-zones that differed significantly in their mean values. ANTHRG and SFRR were inversely correlated over 64% of the plot. SFRR appeared to be a potential useful proxy of yield since it was directly correlated to yield over 66% of the plot. The grape color (ANTHRG) was slightly higher over the low-yield zones with respect to the high-yield zones. Our study showed that the combination of anthocyanins and chlorophyll indices detected in the field on Crimson Seedless table grape by a portable fluorescence sensor can help in defining the best harvest time and the best areas for harvesting.

Rootstocks for the new seedless table grape ‘BRS Vitória’ under tropical semi-arid conditions of São Francisco Valley

ABSTRACT ‘BRS Vitoria’ is the most important Brazilian table grape cultivar in the domestic and foreign markets, standing out for the seedleness, pleasant flavor, high yield and mildew resistance. The aim of the present study was to determine the effect of the rootstock on the yield, production components, vigor, and physical and chemical characteristics of the ‘BRS Vitória’ grape under irrigation in the Brazilian semi-arid region. The experiment was conducted over eight consecutive production cycles in the period from 2015 to 2018 in a commercial area in the Senador Nilo Coelho project, Petrolina, PE. The treatments were represented by seven rootstocks: ‘IAC 572’, ‘IAC 766’, ‘IAC 313’, ‘Harmony’, ‘SO4’, ‘Paulsen 1103’, and ‘Freedom’, using a randomized block experimental design with four replications. The results were variable among production cycles, with significant effects of the rootstock in some cycles and/or in the overall mean of the cycles. The variables of pruning weight, sprouting, bud fertility, and titratable acidity were not affected by the rootstock in any of the production cycles evaluated in this study. ‘Harmony’ rootstock promoted greater berry mass and diameter but reduced the soluble solids content. Vines of ‘BRS Vitória’ showed moderate vigor, high bud fertility and yield, satisfactory characteristics of bunch and berry, sugars and acids content that meet the requirements of the most demanding markets in all the rootstocks evaluated in this study.

Analysis of the phenolic composition and yield of ‘BRS Vitoria’ seedless table grape under different bunch densities using HPLC–DAD–ESI-MS/MS

Grapes are considered to be a major source of phenolic compounds as compared with other fruits. To improve the quality of table grapes, some techniques like thinning can be used. In addition, grape cultivars with distinct characteristics are directly linked to its phenolic profile. This study aimed to identify and quantify the phenolic compound profile and yield of the hybrid 'BRS Vitoria' seedless table grape under different bunch densities, using a combination of solid-phase extraction (SPE) methodologies and analytical high-performance liquid chromatography-diode array detector with tandem mass spectrometry (HPLC-DAD-ESI-MS/MS). A trial was carried out in 2016, in a commercial vineyard at Marialva, state of Parana (South Brazil). Three weeks after anthesis, the following bunch densities were evaluated: 4.0, 4.5, 5.0, 5.5, and 6 bunches per m2 (corresponding to an estimation of 16, 18, 20, 22, and 24 tons ha-1). The randomized block design was used as a statistical model with each treatment was replicated four times, with one vine per plot. Different characteristics were evaluated at harvest, e.g., soluble solids content (SS), total acidity (TA), maturation index (MI=SS/TA), bunch and berry masses, yield, as well hydroxycinnamic acid derivative (HCAD), anthocyanin, flavonol, and flavan-3-ol contents by HPLC-DAD-ESI-MS/MS analysis. The evaluated bunch densities did not interfere with the physicochemical characteristics of the berries, such as SS and MI. Under the density of 6.0 bunches per m2, the highest yield of 25 tons ha-1 was reached. Under all bunch densities, the phenolic profile presented the same compounds, but at different concentrations. Under a density of 5.0 bunches per m2, the compounds belonging to the anthocyanin and flavonol families were present in high concentrations. In contrast, at the densities of 4.0 and 4.5 bunches per m2, there was a reduction in the flavan-3-ol content. With respect to stilbenes, only the trans-piceid and its cis- isomer were detected. However, their concentrations had no significant influence on the evaluated bunch densities.

Yield components of the new seedless table grape ‘BRS Ísis’ as affected by the rootstock under semi-arid tropical conditions

The new seedless table grape cultivar BRS Ísis has high bud fertility, yield and tolerance to downy mildew; its planted area is rapidly increasing in the Vale do São Francisco region in the Northeast of Brazil. The aims of the present study were to evaluate the yield performance, yield components, physical and chemical characteristics of the fruit of the cultivar BRS Ísis grafted onto different rootstocks in irrigated growing in the semi-arid region of Brazil. The experiment was conducted in a commercial vineyard in Petrolina, Pernambuco, over six production cycles in the period 2015-2018. The treatments were represented by the rootstocks IAC 572, IAC 766, IAC 313, Freedom, Harmony, Paulsen 1103, and SO4 in a randomized block design with four replications. There was a greater effect of the production cycle than of the rootstock on all the variables studied, with significant differences between rootstocks in some cycles and/or in the overall mean of the production cycles. Mean production of the six cycles was greatest for IAC 572, at 27 Kg (45 ton/ha/cycle) and 100 clusters per grapevine. The physical characteristics of the clusters and berries and chemical composition of the grape achieved the standards described for the cultivar BRS Ísis and market demands for all the rootstocks.

Postharvest Preservation of the New Hybrid Seedless Grape, ‘BRS Isis’, Grown Under the Double-Cropping a Year System in a Subtropical Area

‘BRS Isis’ is a new hybrid seedless table grape tolerant to downy mildew with a good adaptation to the tropical and subtropical climates. Gray mold, caused by Botrytis cinerea Pers. ex Fr. is known as the most important postharvest mold in table grapes, causing extensive losses worldwide. As the postharvest behavior of ‘BRS Isis’ is still unknown, the objective of this work was to evaluate the postharvest preservation and B. cinerea mold control of this new grape cultivar, grown under the double-cropping a year system. Grape bunches were purchased from a field of ‘BRS Isis’ seedless table grapes trained on overhead trellises located at Marialva, state of Parana (South Brazil). Grapes were subjected to the following treatments in a cold room at 1 ± 1 °C: (i) Control; (ii) SO2-generating pad; (iii) control with bunches inoculated with the pathogen suspension; (iv) SO2-generating pad with bunches inoculated with the pathogen suspension. The completely randomized experimental design was used with four treatments, each including five replicates. The incidence of gray mold and other physicochemical variables, including bunch mass loss, shattered berries, skin color index, soluble solids (SS), titratable acidity (TA), and SS/TA ratio of grapes, were evaluated at 50 days after the beginning of cold storage and at seven days at room temperature (22 ± 2 °C). The ‘BRS Isis’ seedless grape, packaged with SO2-generating pads and plastic liners, has a high potential to be preserved for long periods under cold storage, at least for 50 days, keeping very low natural incidence of gray mold, mass loss, and shattered berries.

Effect of two exogenous plant growth regulators on the color and quality parameters of seedless table grape berries.

Some red-pink table grape varieties, cultivated in warm climates, can fail in achieving the right level of anthocyanins responsible for the intense and uniform red color of berries. Nowadays, this is becoming an important technological issue in the Mediterranean area, which may result in decreasing market acceptance and potential economic value of table grape. Usually, plant growth regulators or phytohormones, such as S-ABA, can overcome this problem because they drive the accumulation of anthocyanins over the ripening season. Harpin proteins (HrP), which enhance the plant disease resistance, may be supposed to stimulate the anthocyanins biosynthesis in grape skin if applied close to veraison. Therefore, this research aimed at comparing the effect of HrP and S-ABA over the anthocyanin and color improvement of Crimson Seedless table grape grown in Southern Italy. For the first time, the exogenous treatment with HrP showed as effective as the less sustainable S-ABA one in favoring the anthocyanin accumulation, leading to peonidin-3-O-glucoside, cyanidin-3-O-glucoside, and malvidin-3-O-glucoside values up to 4 folds higher than control grapes and giving rise to a greater concentration of the more stable acylated anthocyanins. Overall, the color of berries was improved but keeping high the other quality characteristics.

Rootstocks for table grape ‘BRS Clara’ in the São Francisco Valley, northeast Brazil

The present work aimed to evaluate the influence of rootstocks on yield and fruit characteristics of table grape ‘BRS Clara’ under the tropical conditions of the Sao Francisco Valley, northeast Brazil. An experiment was carried out during six growing seasons from 2014 until 2017 in Petrolina, Pernambuco State, Brazil (9°09’S 40°22’W; average altitude 365.5m). ‘BRS Clara’ is a white seedless table grape released by the Genetic Grape Breeding Program of EMBRAPA. It was grafted on six rootstocks: ‘IAC 313’, ‘IAC 766’, ‘IAC 572’, ‘SO4’, ‘Harmony’ and ‘Paulsen 1103’. The results showed that yields were affected by rootstock. Higher yields were obtained for vines grafted onto rootstock ‘Paulsen 1103’ (13.7 t ha(‑1)) than those grafted onto ‘IAC 572’ (5.4 t ha‑1). The number and weight of bunches per vine were also significantly higher in vines grafted on ‘Paulsen 1103’ than on ‘IAC 572’. The physical and physico-chemical characteristics of the grapes, such as length and width of the bunch, weight and diameter of the berry, soluble solids content, titratable acidity and ratio were not influenced by the rootstock. Vines grafted on ‘Paulsen 1103’ presented average values of 21.1 °Brix for soluble solids content and 0.56 g tartaric acid 100 mL(‑1) for titratable acidity. The sugar/acid ratio of 39.8 shows that grapes of very good quality meet the requirements for consumption of different markets. In conclusion, the rootstock ‘Paulsen 1103’ is recommended for table grape ‘BRS Clara’ grown in the Sao Francisco Valley, northeast Brazil, for increasing yield without affecting other quality characteristics of the grape.

‘BRS Vitória’: a new seedless table-grape cultivar for the São Francisco Valley, northeast Brazil

‘BRS Vitoria’ is a seedless table grape released by the grape breeding program of EMBRAPA in 2012. It has attracted great interest from grape growers because of the high fertility of its buds, its exotic and pleasant taste and its tolerance to downy mildew (Plasmopara viticola). The aim of this study was to characterize the agronomic and productive behavior of the grape ‘BRS Vitoria’ under the tropical conditions of the Sao Francisco Valley. The study was carried out over four growing seasons (2014-2015) in a commercial vineyard in Petrolina, Pernambuco state, Brazil. Five plants were evaluated for the following variables: sprouting (%), fertility index of buds, production and number of bunches per plant, biometric measurements of clusters and berries, total soluble solids (SS) content and titratable acidity (TA). ‘BRS Vitoria’ presented a phenological cycle of 104 days from pruning to harvest, being characterized as an early cultivar. ‘BRS Vitoria’ presented high bud fertility and large numbers of bunches per vine. The estimated yield was 36.6 t ha(‑1). Bunches were medium sized and berries were round and black. It had a good SS content and TA and a very pleasant and exotic taste. ‘BRS Vitoria’ was well adapted to produce two crops a year, attracting great interest from table-grape growers, and the cultivated area has reached about 1000 ha in the region of the Sao Francisco Valley, northeast Brazil.

Harpin Proteins Improve Bioactive Compounds Content in Crimson Seedless Table Grape

Background:Frequently, in warm climates such as Mediterranean areas, a red-pink table grape ‘Crimson Seedless’ does not reach a good berry skin color; and an acceptable anthocyanin bioactive compounds content, responsible for the red color of berries. Harpin proteins are biotechnologically developed bio-activators that, if applied on plants during the growing period, trigger the expression of hundreds of genes among which those associated with the biosynthesis of bioactive compounds (such as anthocyanins).Aim:This research aimed at using harpin proteins to test their suitability in improving the grape skin color.Methods and Materials:Beta-harpin protein 1% p.a. (400 g/Ha) was applied to ‘Crimson Seedless’ vines three times at the beginning of veraison. Six samplings were carried out for both the treated and control grapes until commercial harvest. In the skin extracts, total and individual anthocyanins content was determined by UV-Vis and RP-HPLC-DAD analyses, respectively.Results:The collected results confirmed that the application of harpin proteins effectively stimulated the anthocyanin biosynthesis leading to make peonidin-3O-glucoside, cyanidin-3O-glucoside, and malvidin-3O-glucoside values from 2 to almost 10 folds higher in treated grapes than in control grapes (P< 0.05).Conclusion:Actually, harpin proteins improved the color of the berry skin, leading to a significantly higher concentration of anthocyanins in treated than in control grapes.

Proposal of double-cropping system for 'BRS Isis' seedless grape grown in subtropical area

‘BRS Isis’ is a new colored seedless table grape tolerant to downy mildew, the main vine disease in subtropical humid areas. This new seedless cultivar is an interspecific hybrid from the crossing of CNPUV 681-29 [Arkansas 1976 × CNPUV 147-3 (‘White Niagara’ × ‘Venus’)] × ‘BRS Linda’. However, its performance under subtropical conditions hasn´t been assessed yet, especially under double annual cropping system. For this purpose, a research was designed with the objective to characterize the phenology and the main physicochemical properties of this new cultivar. The trial was carried out in a commercial vineyard of ‘BRS Isis’ seedless grape from 2-year-old vines grafted on ‘IAC 766 Campinas’ rootstock, located in Marialva, state of Paraná (PR), Brazil, in two consecutive crops, summer season 2016 and off-season 2017. The vines were trained on overhead trellises and spaced 2.0 × 5.0 m apart. The duration of the main phenological stages of ‘BRS Isis’ were evaluated from pruning until harvest, as well its thermal demand and main physicochemical characteristics. The summer and off-season crop cycles of ‘BRS Isis’ seedless grape grown under subtropical conditions last 144 and 125 days, with thermal demands of 1,931 and 1,815 degree days, respectively. This new seedless grape cultivar can be successfully grown under a double annual cropping system in subtropical conditions, however, as it is a very fruitful cultivar, it is necessary to perform a load crop adjustment after fruit set, equivalent to a density of 5 bunches.m−2, to obtain a sustainable yield in each season. Under this growing system, the berries present in both seasons, appropriate physicochemical characteristics for table grape market, but with darker skin color in off-season. Based on these results, a detailed double annual cropping system, with some specific cultural practices, is proposed for this new hybrid seedless cultivar.

Hexanal formulation reduces rachis browning and postharvest losses in table grapes cv. ‘Flame Seedless’

Rachis browning is one of the major storage problems which reduces the quality and marketability of table grapes. Investigations were carried out to verify the potential of pre-harvest hexanal formulation ‘Enhanced Freshness Formulation’ (US Patent # 6514914: # 7198811 B2) (EFF @ 1.0%, 1.5% & 2.0% v/v) treatment to delay the rachis browning and maintaining the quality of grapes (Vitis vinifera L.) cv. ‘Flame Seedless’ during 2017 and 2018. Grape clusters from treated vines were harvested at the commercial maturity, and then stored at 0–2 °C & 90–95% RH for 60 days. Evaluation of physico-chemical attributes and other fruit quality parameters were made at 0 day (before treatment) and at 15, 30, 45 and 60 days of storage. Hexanal formulation @ 2.0% suppressed the activity of pectin methyl esterase (PME) and browning related enzyme polyphenol oxidase (PPO) with maintained rachis freshness and reduced the rate of cluster weight loss & berry shattering. Hexanal formulation treated bunches retained total soluble solids and titratable acids at higher level during the storage period. In conclusion, the pre-harvest spray of hexanal formulation @ 2.0% proved to be an effective means for delaying the rachis browning and maintaining the quality of Flame Seedless table grapes under prolonged cold storage.

Response of(Vitis vinifera L.)cv. Fantasy Seedless to water deficit treatments: Phenolic compounds and physiological activities

This paper describes an investigation on the effects of deficit irrigation treatments on phenolic compounds and physiological activities of Fantasy Seedless table grape variety. Research was conducted in Viticultural Research Institute of Manisa, located in Aegean Region of Turkey, during two consecutive years (2016–2017). Three irrigation treatments were assayed; namely full irrigation (T-F), deficit irrigations (T-35 and T-65). In T-F, soil water deficit in the 90 cm within the one week intervals was completed to the field capacity. T-35 and T-65 treatments received 35% and 65% of water applied to T-F. Sub-surface drip irrigation system was used in the research and soil water content was measured by MobiCheck probe while vine water status was monitored through midday leaf water potential before the irrigations. Results showed that water deficit treatments (T-35 and T-65) affected berry composition particularly individual phenolics [Gallic acid, (+)(−) Catechine, (−)-Epigallocatechin gallate, (−)-Epicatechin gallate, Caftaric acid, Chlorogenic acid, Caffeic acid, p-Coumeric acid, Ferulic acid, Sinapic acid, Trans-Resveratrol, Myricetin, Quercetin hydrate, Kaempferol, Oenin Chloride, Delphinidin Chloride, Cyanidin Chloride, Malvidin Chloride] differently. The highest Catechine content in the samples was obtained from T-65, T-35 and T-F treatments, respectively. Furthermore it was determined that DI treatments did not change the Myricetin and Quercetin hydrate contents in 2017. On the other hand minimum Ψmdvalue was observed from the T-35 treatment in both years. Last of all, our findings show a strong relationship between the amount of water and berry composition values especially individual phenolics which are benefical to health.

Quality and antioxidant potential of ‘BRS clara’ and ‘Arizul’ grapes influenced by rootstocks in a tropical region

ABSTRACT Seedless table grapes cultivars have been studied in the Sub-middle region of São Francisco Valley at northeast Brazil. For that region, it is important to identify cultivars with productive potential, better quality and efficiency, minimizing the expenses in terms of inputs and workforce, when compared to traditional cultivars. Specifically, the objective of this study was to determine the influence of different rootstocks on the quality and on the antioxidant potential of BRS Clara and Arizul table grapes cultivars of two production cycles. The experimental area belongs to the Experimental Field of Bebedouro/Embrapa Semiárido, located in the sub-middle region of São Francisco Valley, in Petrolina - PE, northeast Brazil. Both BRS Clara and Arizul cultivars were analyzed individually using IAC 313, IAC 572, IAC 766, SO4, Paulsen 1103 and Harmony rootstocks, during production cycles from October/2016 to February/2017 and from March/2007 to June/2017. The experimental design was planned in randomized blocks, in a 2 (production cycle) x 6 (rootstock) factorial, with three replications each. More favorable conditions to quality for ‘BRS Clara’ grapes, as evidenced by higher berry mass, lower soluble solids (SS)/titratable acidity (TA) ratio and higher antioxidant activity, were observed after the March-June, 2017 harvest, especially from scions grafted onto IAC 572, SO4 and Harmony. The Arizul cultivar was characterized by better quality after the March-July, 2017 harvest, showing higher berry mass, lower acidity and lower SS/TA ratio and a better color mainly in SO4 and Harmony rootstocks. Therefore, an appropriate rootstock enhances the quality of the grapes.

Rootstock and soil management effects on productive characteristics of ‘Princess Seedless®’ table grapes in Apulia region (southern Italy): first results

The use of rootstocks on table grape cultivars is required due to phylloxera, nematodes or soil difficulties, like high lime or salt content, drought or high ground water level. The use of inter-row cover crops (permanent or temporary) in viticulture has many advantages, such as reduction of water runoff and soil erosion, restriction of evaporation from the soil surface, improvement in soil water holding and soil organic matter, reduction of temperature fluctuations in the soil, as well as regulation of the vine growth and vigor, with influence on grape quality and quantity. The trial was carried out in 2012-2013 at an experimental vineyard, trained to “tendone trellis system” on ‘Princess®’, (Vitis vinifera L.) a white mid-season muscat-flavored seedless table grape, grafted onto 3 rootstocks: Vitis riparia × Vitis cinerea var. helleri 161.49 C., 34 E.M. and Vitis rupestris × Vitis cinerea var. helleri 140 Ruggeri. Two different soil inter-row space management treatments, tilled cultivation and permanent resident cover crop, were applied in a split-plot design. At commercial harvest, cluster and berry mass, berry diameter, yield per vine, berry chemical composition, skin berry color and berry mechanical parameters were determined. ‘Princess®’ vines exhibited a good performance on all three rootstocks tested. No significant interactions were detected between soil management/rootstocks with regard to cluster weight, berry weight and number per cluster. The soil management/rootstocks interaction was significant for all parameters of chemical composition and skin color coordinates. The highest and statistically different sugar juice content onto 140 Ruggeri and 161.49 rootstocks was noted. Finally, a temporary cover crop with resident vegetation had no negative effects on vine growth and productivity of ‘Princess®’ seedless table grape, with clear benefits of the cover crops in relation to soil compaction, soil water storage and organic matter. Moreover, the rootstocks/soil management interaction affected firmness and berry detachment force.

Estimates of repeatability for selection of genotypes of seedless table grapes for Brazilian semiarid regions

Grapevine (Vitis vinifera L.) produces one of the most consumed fruits in the world. Nonetheless, there is a lack of table grape cultivars that are adapted to Brazilian semiarid conditions. Therefore, there is a need for new table grape cultivars for formation of commercial vineyards in these areas. Thus, the objective of this study was to select promising genotypes for cultivation under semiarid conditions using the methodology of mixed models: restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) models. Eighty-one individual plants (genotypes) were evaluated, in three crop seasons, during the years 2016 and 2017, for six descriptors. The estimates of the repeatability coefficient were high for most of the key traits during table grape breeding, except for total soluble solids (°Bx), 0.28, and the ratio of total soluble solids to titratable acidity (0.30). Predicted selection gains for the 30 superior genotypes provided maximum average values of 46.84 t ha―1 per crop (the yield), 150.64 bunches per plant (number of bunches), and 745.21 g (bunch weight). The selective accuracy predicted for the six evaluated traits revealed a good degree of confidence in the inferences and high precision and selection gain. Using the minimum selection indexes proposed in this study for three crop seasons, genotypes CPATSA 01.02, 02.15, 05.02, 06.123, 15.05, 15.06, 19.06, 19.10, 21.42, and 68.06 were found to be the most promising. In this group, genotypes CPATSA 15.05 and 15.06 stood out because they are completely devoid of seeds. Therefore, these genotypes will be chosen for advanced selection to prove their potential for cultivation in Brazilian semiarid regions.

Cold Storage and Biocontrol Agents to Extend the Storage Period of ‘BRS Isis’ Seedless Table Grapes

‘BRS Isis’ is a novel hybrid seedless table grape with large reddish bunches. This cultivar is cultivated in tropical and subtropical areas and has potential to be exported overseas; however, under these growth conditions, grapes can be severely damaged by gray mold (Botrytis cinerea), the main postharvest disease of table grapes. Thus, this study aimed to evaluate different pre- and postharvest strategies to extend the storage period of ‘BRS Isis’ seedless table grapes. The treatments consisted of grapes packed into carton boxes under cold storage (1 °C and high relative humidity), pre- and/or postharvest treatment with potassium bicarbonate or a biological control agent (Bacillus subtilis), all with Botrytis inoculation. Additionally, two controls, with and without Botrytis inoculation, were also evaluated. The experimental design was completely randomized with eight treatments and three replications, and each plot consisted of four bunches. After a 50-day cold storage period, the carton boxes were kept for five days at room temperature (22 °C). Gray mold incidence and water loss, as well as soluble solids (SS), pH, titratable acidity (TA), SS/TA ratio, and color attributes were evaluated during both periods. Cold storage effectively reduced gray mold in ‘BRS Isis’ seedless grape for a period of 50 days, even when grapes were inoculated; however, no difference among treatments was observed. Higher water loss was observed in both non-treated control treatments.

Postharvest Techniques to Prevent the Incidence of Botrytis Mold of ‘BRS Vitoria’ Seedless Grape under Cold Storage

‘BRS Vitoria’ (Vitis spp.) is a novel hybrid seedless table grape recommended for cultivation in tropical and subtropical areas, especially for overseas export. The main postharvest disease of this cultivar is botrytis or gray mold (Botrytis cinerea), which occurs even under low temperatures in cold chambers. Sulfur dioxide (SO2) release pads have been used to control this disease under cold storage, but some grape cultivars are sensitive to certain levels of this compound. The objective of this work was to evaluate different types of SO2 generator pads in order to prevent the incidence of gray mold of ‘BRS Vitoria’ seedless grape, as well to avoid other grape injuries during cold storage. Grape bunches were harvested when fully ripened (16°Brix) from a commercial field trained on overhead trellis and located at Marialva, state of Parana (PR) (South Brazil). Grapes were packed into carton boxes and subjected to the following SO2 pad treatments (Uvasys®, Cape Town, South Africa) in a cold chamber (2 °C): (a) control; (b) SO2 slow release pad; (c) SO2 dual release pad; (d) SO2 dual release–fast reduced pad; (e) SO2 slow release pad with grapes inoculated with B. cinerea; (f) SO2 dual release pad with grapes inoculated with B. cinerea; and (g) SO2 dual release–fast reduced pad with grapes inoculated with B. cinerea. After a 50-day cold chamber period, the grape boxes were kept for 7 days at room temperature at 25 °C. A randomized design was used with seven treatments and four replications, with five bunches per plot. The incidence of gray mold on grapes was evaluated after the 50-day cold storage and after the 7-days-at-room-temperature periods, as well other grape physicochemical variables, such as shattered berries, stem browning, bunch mass, bunch mass loss, skin color, soluble solids (SS), titratable acidity (TA), and SS/TA. The dual release pads were more efficient in preventing the incidence of gray mold and mass loss in ‘BRS Vitoria’ seedless grapes than the slow release pads in both storage periods. The incidence of shattered berries was lower when any type SO2 pad was used during cold storage, and no effects were observed on stem browning, firmness, or berry skin color of ‘BRS Vitoria’ grapes.