Search Results (22)

The vigorous growth of new shoots can significantly reduce grape yield and compromise fruit quality. In order to explore the effects of prohexadione calcium (Pro-Ca) and mepiquat chloride (MC) on the control effect of new shoot growth and fruit quality of grape, ‘Shine Muscat’ grapevine (Vitis labruscana × V. vinifera) was used as the test material, and different concentrations of Pro-Ca and a combination of Pro-Ca and MC were sprayed four times before flowering of ‘Shine Muscat’ grapevines, and the effects of the different treatments on the new shoot growth and fruit quality of ‘Shine Muscat’ grape were analyzed and evaluated. The results demonstrated that low concentrations of Pro-Ca had limited efficacy in controlling shoot growth. However, the combined treatment of Pro-Ca 300 mg/L + MC 300 mg/L not only effectively inhibited shoot elongation but also significantly enhanced the chlorophyll content of the leaves opposite to the clusters and increased branch density. Additionally, this treatment improved berry size (single berry weight, vertical and horizontal diameter) and elevated the soluble solids content (SSC). These findings suggest that the combined application of Pro-Ca (300 mg/L) and MC (300 mg/L) is the most effective strategy for balancing vegetative growth and enhancing fruit quality in ‘Shine Muscat’ grapevines. Full article

Table grapes are among the main fruit crops cultivated in Brazil, supported by cultivar diversity, technological advances, and adaptation to diverse edaphoclimatic conditions. Rootstock selection is critical in viticulture, influencing phenology, yield, and fruit quality. This study evaluated yield- and fruit-related production parameters, cluster characteristics, and biochemical composition of ‘BRS Núbia’ table grape grafted onto different rootstocks. The experiment was conducted at the Experimental Farm of the Faculty of Agricultural Sciences (UNESP), São Manuel, São Paulo, Brazil, using a randomized block design in a split-plot scheme (three rootstocks × three seasons) with seven replicates. Rootstocks included ‘IAC 572 Jales’, ‘IAC 766 Campinas’, and ‘Paulsen 1103’, while subplots corresponded to the first three production seasons after grafting. Evaluated variables comprised bud fruitfulness, yield, productivity, physical attributes of clusters, berries, and rachises, and in 2022, berry biochemical traits, including total phenolics, flavonoids, anthocyanins, and antioxidant activity. Rootstocks did not significantly affect bud fruitfulness or yield-related parameters. In contrast, production season markedly influenced vine performance, with the third (2023) season showing higher cluster and berry mass and size. Regarding fruit composition, vines grafted onto ‘Paulsen 1103’ and ‘IAC 766 Campinas’ showed greater accumulation of total phenolics and anthocyanins than those grafted onto ‘IAC 572 Jales’, overall. Full article

Gibberellin (GA)-based seedless cultivation is widely used in the skin-edible interspecific table grape (Vitis labruscana × Vitis vinifera) ‘Shine Muscat’, yet when and how GA treatment reshapes fracture-type texture during berry development remains unclear. This study aimed to identify developmental stages and tissue/cell-wall features associated with GA-dependent differences in berry fracture behavior. We integrated intact-berry fracture testing at harvest (DAFB105), quantitative histology of pericarp/mesocarp tissues just before veraison (DAFB39) and at harvest, sequential cell-wall fractionation assays targeting pectin-rich (uronic acid) and hemicellulose/cellulose-related pools at cell division period, cell expansion period and harvest, and stage-resolved RNA-Seq across the same three developmental stages. GA-treated berries had a larger diameter and showed a higher fracture load and a lower fracture strain than non-treated berries at harvest, while toughness did not differ significantly. Histology revealed thicker pericarp tissues and lower mesocarp cell density in GA-treated berries, together with increased cell-size heterogeneity and enhanced radial cell expansion. Cell wall analyses showed stage-dependent decreases in uronic acid contents in water-, EDTA-, and Na₂CO₃-soluble fractions in GA-treated berries. Transcriptome profiling indicated GA-responsive expression of putative cell expansion/primary-wall remodeling genes, EXORDIUM and xyloglucan endotransglucosylase/hydrolases, at DAFB24 and suggested relatively enhanced ethylene-/senescence-associated transcriptional programs together with pectin-modifying related genes, Polygaracturonase/pectate lyase and pectin methylesterase, in non-treated mature berries. Collectively, GA treatment modifies mesocarp cellular architecture and pectin-centered wall status in a stage-dependent manner, providing a tissue- and cell wall–based framework for interpreting fracture-related texture differences under GA-based seedless cultivation in ‘Shine Muscat’. Full article

There is increasing interest in foods that support both physical and psychological health. Red and black fruits are notable for their high phenolic content and associated biological activities. However, their natural sugar content may raise concerns regarding glycemic impact. Recent breeding programs have developed new seedless table grape varieties with black skin and red pulp, aiming to enhance phenolic content and reduce glycemic response. This study evaluates these novel grape varieties using in vitro models of intestinal absorption and hepatic insulin resistance. Specifically, we assessed phenolic content, antioxidant capacity, glucose transport across intestinal cells, and the modulation of biomarkers related to insulin resistance. The results showed that the new grape varieties (hybrids) showed total phenolic contents of 52.4–187.3 mg GAE/100 g FW and antioxidant capacities ranging between 195.3 and 762.7 mg Trolox equivalents/100 g FW, both higher than those of commercial table grapes. These new varieties also showed a lower percentage of intestinal glucose transport than commercial grapes and pineapple in caco-2 cells, suggesting an improved regulation of glucose uptake. Theoretical transport values confirmed a reduced glycemic impact for most hybrids, while absorbed fractions of RF03, RF05, and RF06 also restored hepatic glycogen levels under insulin-resistant conditions, indicating enhanced glucose metabolism. Overall, our in vitro findings suggest that these new grape varieties may help modulate postprandial glucose levels, supporting their potential as a healthier fruit option. Full article

Plant growth regulators (PGRs) are widely used to enhance table grape quality, yet cultivar-specific responses and microstructural outcomes remain insufficiently resolved. We evaluated five PGRs—gibberellic acid (GA₃), 24-epibrassinolide (EBR), forchlorfenuron (CPPU), thidiazuron (TDZ), and streptomycin (SM)—in ‘Shine Muscat’ and ‘Red Muscat of Alexandria’. Twelve combinations were applied at full bloom (D0) and 14 days post-anthesis (D14), and morphological, physiological, and histological traits were monitored over 104 days. In ‘Shine Muscat’, GA₃ + TDZ and GA₃ + CPPU achieved nearly 100% seedlessness, while CPPU and TDZ markedly increased berry weight and size via cortical expansion. GA₃ increased berry weight but caused rachis thickening and reduced total soluble solids (TSS). EBR at concentrations ≥ 0.2 mg L⁻¹ inhibited berry growth, and SM reduced berry size and weight. Histology showed that TDZ and CPPU enlarged cortical area and epidermal thickness, potentially strengthening pericarp robustness, whereas GA₃ enlarged vascular bundle area. ‘Red Muscat of Alexandria’ showed generally weaker responses, reflecting differences between Vitis vinifera and hybrid backgrounds. These results demonstrate that combinatorial PGR strategies can be tailored to optimize berry development and quality through coordinated regulation of growth, metabolism, and microstructure. TDZ and CPPU exhibit strong production potential for enlargement, whereas GA₃ and EBR require careful dose optimization to balance benefits and quality risks. Full article

Table grape breeding programmes are ongoing in different countries to develop new grape cultivars suitable for rapidly changing consumer demands. Although Türkiye is among the world’s leading countries in table grape production, it does not have quality grape cultivars that can compete in foreign markets. Different breeding programmes are conducted in the country to develop new quality table grape cultivars. These breeding studies’ primary goals are to achieve table grapes that are seedless, with crispy flesh, a large berry size, unique aromas, higher phenolic contents, and improved disease resistance. This study evaluated the basic quality characteristics of 89 hybrid genotypes with different parents obtained from crossbreeding studies and passing the preliminary screening stage. The hybrid genotypes were evaluated comprehensively for many quality criteria. In particular, the hybrid genotypes that received the desired score according to tasting panel results were determined. Among these, genotypes 22BY-097, 14KS-03, 18BK-02, and 22BY-044, which are seedless and have different parents, were the highest-scoring hybrid genotypes, due to their different superior characteristics. High-scoring hybrid genotypes will be registered after these quality characteristics are evaluated in different locations in the next stage. Consequently, the accuracy and consistency of the results obtained will be confirmed, and new cultivars will be transferred to table grape growers in the future. With these high-quality new cultivars, table grape growers can earn more income. Full article

In this study, the aroma of 182 table grapes was detected using a PEN3.5 electronic nose in order to explore the aroma components of table grape berries and provide a reference for aroma evaluation and quality improvements. Table grape varieties from the Zhengzhou Fruit Research Institute of the Chinese Academy of Agricultural Sciences were used as research materials. All of them were harvested in fruit trees over 10 years old from August to October 2023, which provided a reference for aroma evaluation and quality improvement of the table grapes. Radar analysis, correlation analysis, principal component (PCA) analysis, cluster analysis, and difference analysis were used to study these aroma substances. The results show that the sensor contribution rate from high to low is W5S (nitrogen oxides), W2S (alcohols and some aromatic compounds), W1S (alkanes), and W2W (sensor contribution rate from high to low). Cluster analysis can distinguish the varieties of table grapes a with common aroma content, and the varieties with a higher content are in the second category (II). PCA showed that the contribution rate of the first and second principal components of the three main sensors was 97.6% and 2.3%, respectively, and the total contribution value was 99.9%. The contribution rates of the first and second principal components of the three aromatic sensors are 79.5% and 15.9%, respectively, and the total contribution value is 95.4%. The results showed that there were significant differences in the content and composition of aroma substances in different grape varieties. Eight special germplasm with strong aroma (organic compounds of nitrogen oxides, alcohols, alkanes and sulfur) were selected: ‘Spabang’, ‘Neijingxiang’, ‘Zaotian Muscat’, ‘Jinmeigui’, ‘Zhengguo 6’, ‘Muscat Angel’, ‘Zizao’, and ‘Qiumi’. This study confirmed that electronic nose technology can effectively distinguish different varieties of table grapes. This study not only provides a scientific basis for the variety selection for the table grape processing industry, but it can also be used for male or female grape hybridization, which provides valuable data resources for table grape breeding. Full article

Sulfur dioxide (SO₂) is the most effective preservative for table grapes as it reduces the respiratory intensity of berries and inhibits mold growth. However, excessive SO₂ causes berry abscission during storage, resulting in an economic loss postharvest. In this study, grapes were exogenously treated with SO₂, SO₂ + 1.5% chitosan, SO₂ + 1.5% eugenol, and SO₂ + eugenol-loaded chitosan nanoparticles (SN). In comparison to SO₂ treatment, SN treatment reduced the berries’ abscission rate by 74% while maintaining the quality of the berries. Among the treatments, SN treatment most effectively inhibited berry abscission and maintained berry quality. RNA-sequencing (RNA-seq) revealed that SN treatment promoted the expression of genes related to cell wall metabolism. Among these genes, VlCOMT was detected as the central gene, playing a key role in mediating the effects of SN. Dual luciferase and yeast one-hybrid (Y1H) assays demonstrated that VlbZIP14 directly activated VlCOMT by binding to the G-box motif in the latter’s promoter, which then participated in lignin synthesis. Our results provide key insights into the molecular mechanisms underlying the SN-mediated inhibition of berry abscission and could be used to improve the commercial value of SO₂-treated postharvest table grapes. Full article

Seedlessness is one of the highest valued agronomic traits in grapes. Embryo rescue in combination with marker-assisted selection have been widely applied in seedless grape breeding due to the advantages of increasing the ratio of seedless progenies and shortening the breeding cycle. However, the large number of deformed seedlings produced during embryo rescue and the lack of fast, efficient, and low-cost markers severely inhibit the process of seedless grape breeding. In this study, a total of eighty-three grape cultivars (51 seedless and 32 seeded) with diverse genetic backgrounds and two populations derived from embryo rescue, including 113 F1 hybrid individuals (60 seedless and 53 seeded), were utilized. We screened suitable media for converting malformed seedlings into normal seedlings, analyzed the association between the SNP in VviAGL11 and seeded/seedless phenotype, and developed a KASP marker related to stenospermocarpic seedlessness. Our results indicated that the transformation rate of 37.8% was obtained with MS medium supplemented with 2.0 mg·L⁻¹ of 6-BA and 0.5 mg·L⁻¹ of IBA. The presence of an A nucleotide allele at position chr18:26889437 was further confirmed to be fully associated with the stenospermocarpic seedlessness phenotype. The developed KASP marker, based on the verified SNP locus in VviAGL11, successfully distinguished the seedless and seeded genotypes with high precision and throughput. The results will contribute to enhancing the efficiency of embryo rescue and facilitate parent selection and early selection of seedless offspring with molecular markers, thereby accelerating the breeding process in seedless table grapes. Full article

Brazil has emerged as a significant producer of seedless grapes due to high consumer demand. This has led to increased production of seedless grapes in non-traditional cultivation regions, such as subtropical areas. To meet this demand, the search for new grape varieties suitable for these conditions, such as the ‘BRS Isis’ variety, has become an option for growers. The interaction between grape cultivars and rootstocks is specific, and their adaptability to climatic conditions can result in uneven performance. Therefore, the choice of rootstock should be considered before making any recommendations. The purpose of this study was to assess the productive performance, physical-chemical, and biochemical properties of the ‘BRS Isis’ vine grafted onto rootstocks (‘IAC 572’, ‘IAC 766’, and ‘Paulsen 1103’) in two production cycles. The experimental design consisted of randomized blocks, with seven blocks and three plants per plot, for a total of 63 vines. Thus, the vine’s income components, physical qualities of bunches and berries, chemical profile, bioactive substances, and antioxidant activity were assessed. The Tukey test (5% probability) was used to compare means between rootstocks. The data on scion cultivar and rootstock pairings were further evaluated using principal component analysis (PCA). There were substantial variations in the rootstocks, with ‘IAC 572’ and ‘IAC 766’ producing more bunches, generating more fresh mass, and having a longer bunch length than ‘Paulsen 1103’. However, phenolic compounds and flavonoids were greater in ‘BRS Isis’ grapes than in ‘Paulsen 1103’. ‘BRS Isis’ shows good adaptation to subtropical environments when employing the IAC 572 and IAC 766 rootstocks due to their higher yield and bioactive component accumulation compared to grapes grafted onto ‘Paulsen 1103’. However, regardless of the rootstock utilized, ‘BRS Isis’ grapes perform well commercially in subtropical environments. Full article

French-American hybrids and North American grape species play a significant role in Canada’s grape and wine industry. Unfortunately, the occurrence of viruses and viral diseases among these locally important non-vinifera grapes remains understudied. We report here the results from a large-scale survey to assess the prevalence of 14 viruses among 533 composite samples representing 2665 vines from seven French-American hybrid wine grape cultivars, two North American juice grape cultivars (Concord and Niagara), and the table grape cultivar Sovereign coronation. Based on reverse transcription polymerase chain reaction (RT-PCR) assays, ten viruses were detected. Grapevine rupestris stem pitting-associated virus, grapevine leafroll-associated virus 3, grapevine Pinot gris virus and grapevine red blotch virus were detected with the highest frequency. As expected, mixed infections were common; 62% of the samples contained two or more viruses. Overall, hybrid wine grapes were infected with more viruses and a higher prevalence of individual viruses than juice and table grapes. To validate these findings and to refine the virome of these non-European grapes, high-throughput sequencing (HTS) analyses of five composite samples representing each category of grapevine cultivars was performed. Results from HTS agreed with those from RT-PCR. Importantly, Vidal, a widely grown white-wine grape with international recognition due to its use in the award-winning icewine, is host to 14 viruses, four of which comprise multiple and distinct genetic variants. This comprehensive survey represents the most extensive examination of viruses among French-American hybrids and North American grapes to date. Full article

Seedlessness in grapes is much appreciated by consumers and especially in cultivars consumed either as table grapes or as raisins. In many parts of the world, low temperature is the main environmental stress limiting grape production. In this study, stenospermocarpic (seed abortion) cultivars were selected as the female parents while seeded cold-resistant cultivars were selected as the male parents to develop new cold-resistant seedless grapes using embryo rescue technology, which has previously been shown to be a highly efficient way of breeding seedless grapes. Here, we report optima in genotype, sampling time, and culture medium for the embryo rescue of 14 hybrid combinations. Our results indicate that the embryo development rate (39.9%) and the seedlings rate (21.5%) were highest among the 14 crosses when ‘Ruby Seedless’ was used as the female parent and ‘Beibinghong’ was used as the male parent. The best sampling times for ‘Yuehong Wuhe’, ‘Ruby Seedless’, and ‘Melissa seedless’ were 37, 55, and 52 days after flowering, respectively. Embryo rescue efficiency was highest when the sucrose concentration for seedlings was maintained at about 1.0%. Using molecular markers, we detected 91 hybrids with seedless traits and 18 hybrids with cold resistance traits. Full article

South Africa is associated with a centuries-old viticultural industry, accompanied by a diverse range of wine and table grape cultivars and an extensive history of pervasive introductions of vine material and associated viruses. The Vitis D2 collection in Stellenbosch represents the most comprehensive collection of Vitis species, hybrids, and cultivars in South Africa. We collected leaf petiole material from 229 accessions from this collection. Our metaviromic analyses revealed a total of 406 complete/near complete genomes of various betaflexiviruses. Among these, we identified the presence of grapevine rupestris stem pitting-associated virus and grapevine viruses A, B, E, F, H (GVH), I (GVI), and M (GVM). Notably, this study marks the first report of GVH, GVI, and GVM in South Africa, which were confirmed via RT-PCR. This research significantly contributes to our understanding of viral diversity and introductions in South African viticulture and emphasizes the need for vigilant monitoring and management of viral infections. Our findings lay the groundwork for strategies that mitigate the impact of viruses on South Africa’s wine industry, which generates an annual revenue of approximately 500 million USD. Full article

Grape powdery mildew caused by Erysiphe necator (Schw.) Burr. is a destructive disease in vineyards. Synthetic fungicides are the main tool to combat this disease. The search for new alternatives to reduce pesticide usage and tactical approaches for resistance management encouraged us to develop the novel strategy that we report here. We evaluated the efficacy of a new premixed hybrid fungicide containing the demethylation inhibitor (DMI) difenoconazole and essential tea tree oil (TTO), derived from the Melaleuca alternifolia plant, against grape powdery mildew in seven field trials and two large-scale demonstration trials conducted in two different regions in the world, including Chile and Israel. Foliar sprays of difenoconazole-TTO were applied as a preventive treatment in field trials at 40–80 up to 80–160 gr/ha active ingredient, and they were highly effective in controlling powdery mildew on the fruit clusters of both wine and table grapes in experimental and large-scale demonstration trials and provided up to 99% efficacy in disease incidence and severity compared with the untreated control. Difenoconazole-TTO was as or more effective than other DMI fungicides, including difenoconazole, a pre-mixed fungicide boscalid-pyraclostrobin, or treatments that included various fungicides applied in rotation or mixtures of fungicides. The results suggest that a combination of difenoconazole-TTO with a reduced synthetic chemical load can be included in powdery mildew control programs for grapevine as a strategic approach in fungicide resistance management in vineyards. Full article

This study aimed to identify the aromatic compounds present in the different aroma types of different table grape varieties and deeply understand the changes in the aromatic compounds during the growth and development process. The skin and flesh of three table grape varieties (‘Kyoho’, ‘Shine Muscat’, and ‘Ryuho’) in different growth and development stages were selected to determine their aromatic compounds using headspace solid-phase microextraction gas chromatography-mass spectrometry and principal component analysis. The results showed that the aromatic compounds of the ‘Kyoho’ and ‘Ryuho’ grapes were similar, mainly containing C₆ compounds and esters, whereas ‘Shine Muscat’ was characterized by C₆ compounds and terpenes. The levels of aromatic compounds in the skin were higher than those in the flesh. The content of esters in ‘Ryuho’ was significantly higher than that in ‘Kyoho’ and ‘Shine Muscat’. This showed that ‘Ryuho’ combines the advantages of the parents in its aroma composition. Selecting suitable parents for hybridization is one method for obtaining new varieties with a special aroma. This provides a theoretical basis for future molecular hybrid breeding and molecular-assisted breeding, as well as molecular biology research on aroma synthesis and metabolism in table grapes. Full article