Grape Breeding Programs Research Articles

Genome-wide identified VvOFP genes family and VvOFP4 functional characterization provide insight into fruit shape in grape

Ovate Family Proteins (OFPs) are emerging as novel transcriptional regulators of fruit shape. Despite their established role in various species, their involvement in regulating grape fruit shape remains understudied. This study encompassed a comprehensive evaluation of 16 grape OFP genes in total at the whole genome level. Phylogenetic and synteny analyses established a close relationship between grape VvOFP genes and their tomato counterparts. Expression profiling post-treatment with gibberellic acid (GA3) and thidiazuron (TDZ) revealed that certain OFP genes responded to these regulators, with VvOFP4 showing peak expression three days post-anthesis. Functional assays via overexpression of VvOFP4 in tobacco and tomato altered the morphology of both vegetative and reproductive organs, including leaves, stamens, and fruits/pods. Paraffin sections of transgenic tobacco stems and tomato fruits demonstrated that VvOFP4 overexpression modifies cell dimensions, leading to changes in organ morphology. Additionally, treatments with GA3 and TDZ similarly influenced the shape of grape pulp cells and thereby the overall fruit morphology. These findings suggest that the VvOFP4 gene plays a crucial role in fruit shape determination by modulating cell shape and presents a potential target for future grape breeding programs aimed at diversifying fruit shapes.

Uncovering the molecular mechanisms of russet skin formation in Niagara grapevine (Vitis vinifera × Vitis labrusca)

Grape breeding programs are mostly focused on developing new varieties with high production volume, sugar contents, and phenolic compound diversity combined with resistance and tolerance to the main pathogens under culture and adverse environmental conditions. The ‘Niagara’ variety (Vitis labrusca×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document}Vitis vinifera) is one of the most widely produced and commercialized table grapes in Brazil. In this work, we selected three Niagara somatic variants with contrasting berry phenotypes and performed morphological and transcriptomic analyses of their berries. Histological sections of the berries were also performed to understand anatomical and chemical composition differences of the berry skin between the genotypes. An RNA-Seq pipeline was implemented, followed by global coexpression network modeling. ‘Niagara Steck’, an intensified russet mutant with the most extreme phenotype, showed the largest difference in expression and showed selection of coexpressed network modules involved in the development of its russet-like characteristics. Enrichment analysis of differently expressed genes and hub network modules revealed differences in transcription regulation, auxin signaling and cell wall and plasmatic membrane biogenesis. Cutin- and suberin-related genes were also differently expressed, supporting the anatomical differences observed with microscopy.

New table grape hybrids development from teinturier population with enhanced phytochemical quality

According to consumer demands, table grape breeding programs work to obtain innovative high quality seedless varieties with new flavours and shapes, high yields, adapted to environmental conditions, and resistant to diseases and pests. Therefore, our objective was to study 9 selected table grapes hybrids with potential market acceptance in terms of sensory and physicochemical quality, and their main bioactive compounds content during two consecutive seasons. A total of 71 hybrids were initially obtained from their parentals [‘Alicante Bouschet’ (AB) × ‘Itumfifteen’ (IT-15)]. Selected hybrids were classified according to the red colour of the flesh: non-coloured (NCF), partially coloured (PCF), and totally coloured (TCF). PCF and TCF hybrids showed 1.1–2-fold higher phenolic acids, 1.1–5.5-fold in flavonols, 1–5-fold in stilbenes, and between 1.3- and 48.4-fold in anthocyanins, respectively compared to their parentals (AB and IT-15). These were related to increases of 1.2–3.6-fold in total antioxidant capacity (TAC), being berry flesh responsible for the content of 43 % of such bioactive compounds. Therefore, the coloured flesh selected hybrids of the studied teinturier population were enhanced in phytochemical quality regarding their parentals, which has led in the development of potential healthier varieties for human consumption.

Multitrait selection in seedless grape hybrids in semiarid regions of Brazil

AbstractThe absence of seeds has been one of the most valued traits in grapes (Vitis spp.) for fresh consumption. However, the simultaneous selection of superior genotypes for multiple traits is complex. The objective of this study was to select genotypes of superior seedless table grapes in semiarid regions of Brazil. Multiple traits were considered by using the factor analysis and genotype–ideotype best linear unbiased prediction (FAI‐BLUP) selection index. A total of 110 grape progenies from 24 crosses were evaluated for traits of agronomic interest. Each hybrid was represented by a single vine plant, without experimental design or repetition. The mixed‐model methodology was used to predict the breeding values. The FAI‐BLUP index was used to select superior genotypes based on factor analysis and the genotype–ideotype distance. Four factors explained the 11 characteristics studied, with a variability of 81.84%. Desirable gains were observed for 10 of the 11 traits evaluated. The FAI‐BLUP index allowed the selection of superior seedless table grape hybrids, which can be used in the genetic improvement of grapevines. In conclusion, we report the selection of seedless table grape hybrids for our study to advance in the table grape breeding program in Brazilian semiarid regions.

Content of phenol and stilbene compounds and gene expression related to fruit development during ripening in Ampelopsis

Grapes are used worldwide and are rich in polyphenols, such as anthocyanins and stilbene compounds. Wild grapes contain abundant stilbene compounds, which are beneficial to humans. This study examined the polyphenol content and gene expression involved in skin coloration in the ripening stage of Ampelopsis spp. Accession compared to ‘VC-1’ (Vitis coignetiae) and ‘Super Hamburg’ (V. labruscana). The flavonoid content was generally higher in the Ampelopsis fruit than in the other grape lines, and the highest content among Ampelopsis accessions was found in ‘YG10075’ at 9.67 mg quercetin equivalent (QE) per g fresh weight. The anthocyanin content was highest in ‘VC-1’ at 1.2% (w/w), and the Ampelopsis accession with the highest anthocyanin content was ‘YG10062’ with 0.27%. The resveratrol content was highest in ‘VC-1’ at 70.4 μg/g, and the Ampelopsis accession with the highest resveratrol content was ‘YG10075’ with 48.5 μg/g. Expression levels of genes involved in skin color development increased during maturation in ‘VC-1’ and ‘Super Hamburg’, but decreased with maturation in Ampelopsis ‘YG10042’, ‘YG10075’, and ‘YG10062’. The expression of the genes related to stilbene compound synthesis, skin coloration, and reactive oxygen species (ROS) was high in the leaves of ‘YG10045’, young berries of ‘YG10075’, and ripe berries ‘YG-Songni4’. The gene expression showed different patterns depending on the accession of Ampelopsis, the organ, and the ripening stage. Our results indicate that ‘YG-Songni4’ is the most valuable Ampelopsis spp. accession with the highest expression of genes related to synthesis of stilbenic compounds throughout all organs. This accession could be a useful genetic resource in grape breeding programs.

Folic acid delays postharvest quality deterioration of table grape by regulating cell wall metabolism-associated hub WRKY31 transcription factor

Grape (Vitis vinifera L.) berries are susceptible to quality deterioration after harvest. This study aimed to investigate the effect of folic acid (FA) treatment on the postharvest quality of table grape berries. Harvested ‘Kyoho’ (V. vinifera × V. labrusca L.) bunches were immersed in 1 mg L−1 FA solution for 15 min, then stored for sample collection and phenotype observation. Treatment with FA decreased the rates of berry abscission, water loss, and berry softening, reduced the accumulation of reactive oxygen species (ROS), and altered ROS metabolism-associated enzyme activities and gene expression levels. Transcriptome analysis revealed 507, 684, and 250 differentially expressed genes (DEGs) between FA-treated and non-treated berries at 3, 6, and 9 d after treatment, respectively. The DEGs were grouped into six modules according to a weighted correlation network analysis. A hub transcription factor, annotated as a WRKY transcription factor, was screened from the module associated with cell wall metabolism and identified as VvWRKY31. Transient transformation of grape berry slices revealed that overexpression of VvWRKY31 enhanced the relative expression level of VvRboh. The dual-luciferase assay showed that VvWRKY31 was capable of binding to VvRboh promoter. The present results provide insights into the potential molecular mechanism underlying FA-induced delay postharvest quality deterioration of grape berries. Specifically, FA inhibits expression of genes associated with ROS generation by reducing VvWRKY31 expression, thereby delaying quality deterioration induced by excessive accumulation of ROS. These results will be helpful in table grape breeding programs focused on delaying deterioration in postharvest quality.

Postharvest Potential of Cold-hardy Table Grapes

The University of Minnesota Grape Breeding Program has developed cold-hardy wine grape cultivars that have facilitated the establishment of an economically important grape industry for the Midwest region. In recent years, the program has renewed efforts to breed cold-hardy table grapes. Table grapes might require postharvest storage if they are to be transported or stored for any period of time. Rachis dehydration, berry splitting, and decay can affect the postharvest quality of table grapes. In this study, we evaluated these postharvest traits in six released cultivars and nine advanced selections in the breeding program. For two growing seasons, we used industry standard packaging to assess postharvest traits (rachis dehydration, berry splitting, decay, and overall acceptability) at 2, 4, and 6 weeks of cold storage at 2.2 °C. The growing season had a significant effect on postharvest traits; therefore, the two were examined separately. There were significant differences in postharvest storage times for all traits, except berry splitting in 2020. Mean rachis dehydration reached unacceptable values (>3) after 4 weeks of postharvest storage in 2019 and after 6 weeks in 2020. All other trait means remained acceptable for many cultivars even after 6 weeks of postharvest storage. Advanced selections performed at and above the level of released cultivars, suggesting that selections will perform well in cold-hardy regions. The data collected regarding fruit quality and postharvest storage for two seasons will help to inform and improve breeding of cold-hardy grape cultivars.

Pyramiding of resistance alleles to grape powdery mildew assisted by molecular markers

Disease resistance gene pyramiding is a widely used strategy to enhance resistance durability. Marker-assisted selection (MAS) was applied to pyramide the alleles Run1 and Ren3, which confer resistance against grape powdery mildew (Erysiphe necator). Two F1 full-sibs carrying Run1 and Ren3 in heterozygosity were selfed to develop the breeding populations used in the analysis. From the 637 genotyped plants, 313 (50.6%) had the Run1 and Ren3 pyramided. Seven (1.1%) of them exhibited the two resistance alleles in homozygosity. Plants without any resistance alleles had the highest disease severity ( = 7.3), while the ones with the Run1 allele both in homozygosity and heterozygosity were highly resistant ( = 1.5). Similar level of resistance was observed in the plants containing Run1 and Ren3 pyramided ( = 1.3). Plants containing Run1 and Ren3 pyramided in homozygosity are important genetic resources for grape breeding programs in Brazil.

Embryo Rescue of Cold-hardy Table Grapes

Seedlessness is one of the most desirable traits for table and raisin grapes. Stenospermocarpic cultivars are desirable because they have large berries with superior quality. Embryo rescue techniques have been widely used to get progeny seedling populations from crosses using seedless mother plants. Selection of the female parent, sampling time, and the growth medium are the most crucial to the success of this technique. This study investigated the effect of best sampling time and media composition on embryo rescue efficiency in a cold-hardy hybrid grape breeding program. We sampled ovules 5 to 9 weeks after flowering, and we tested four media compositions. The greatest percentages of embryo germination and normal seedlings were obtained when ovules were harvest at 8 weeks after flowering, indicating that it is suitable to harvest ovules at veraison, when the extraction of ovules is easier as a result of softer berry flesh. For the media composition experiment, all ovules were harvested at 8 weeks after flowering. Nitsch & Nitsch culture medium had very low germination, and the resulting seedlings performed the lowest compared with the other treatments. Lloyd & McCown Woody Plant Basal Medium (WPM) increased the number of embryos germinated significantly, and a number of normal seedlings and plantlets developed. Although there was no significant difference among the other three media containing WPM supplemented with different doses of plant regulators, the WPM Plus medium [with cytokinin (6-benzlaminopurine), indole-3-butyric acid, gibberellin, and casein hydrolysate] promoted the greatest percentage of established plants (46.98%). Therefore, the 8-weeks-after-flowering harvest time and the WPM Plus medium were selected for use in the embryo rescue protocol at the University of Minnesota grape breeding program.

Evaluation of powdery mildew resistance of a diverse set of grape cultivars and testing the association between powdery mildew resistance and PR gene expression

Powdery mildew caused by the fungal pathogen Erysiphe necator is a global disease that reduces yield and quality in grapes (Vitis vinifera L.). Most grape cultivars are susceptible to this pathogen and thus the selection of powdery mildew resistant cultivars is a major objective of grape breeding programs. In this study, we evaluated powdery mildew resistance of a diverse set of 28 commonly cultivated local and international V. Vinifera cultivars after artificial inoculations with Erysiphe necator. Of these, 7 cultivars were found to be resistant while 10 and 11, were found to be moderately resistant and susceptible to powdery mildew, respectively. We also analyzed pathogen-responsive expression profiles of two defense genes, VvPR1 and VvGLP3 encoding a pathogenesis-related protein 1 homolog and a Germin-Like protein, respectively, in the same cultivars by qRT-PCR to determine whether defense gene expression is correlated with powdery mildew resistance. There was no significant correlation between powdery mildew ratings and induction patterns of these two defense genes. However, a significant correlation was found between VvPR1 and VvGLP3 expression only in cultivars that showed increased powdery mildew resistance. In addition, the grape cultivars we analyzed differed by berry ripening times, were shown to influence disease resistance. However, no significant correlation was found between powdery mildew ratings and the ripening times. Although potential mechanisms of powdery mildew resistance or susceptibility remain unclear, powdery mildew resistant grape cultivars identified here will be useful for growers and breeders interested in using these lines as parents in grape breeding programs.

Immunogenic breeding program. Stage I-phytopathological screening of the grape gene pool

At the present stage of science development it is necessary to develop and implement the grape breeding programs for immunity basing on the international level of knowledge about the genetics of immunity to pathogens that cause culture diseases. The extensive material on genes of grape resistance to Plasmopara viticola and Erysiphe necator (Uncinula necator), which cause mildew and oidium diseases, has been collected thanks to the MAS technology. There is an evidence of necessity to pyramidize genes of resistance to these pathogens in one progeny genome for consistent field resistance to the complex of these pathogens. However, even at present, the issue of study the transfer of specific genes of resistance from parents to the progeny, their combining ability in one genome, and gene expression during pathogenesis remains relevant. This publication discusses the formation of grape breeding program in the FSBSI Institute Magarach of the RAS on introgression of resistance genes of the species Vitis rotundifolia (Muscadinia rotundifolia), and also presents the results of phytopathological screening of populations resulting from crossing with this species.

Genetic structure and molecular diversity of Brazilian grapevine germplasm: Management and use in breeding programs.

The management of germplasm banks is complex, especially when many accessions are involved. Microsatellite markers are an efficient tool for assessing the genetic diversity of germplasm collections, optimizing their use in breeding programs. This study genetically characterizes a large collection of 410 grapevine accessions maintained at the Agronomic Institute of Campinas (IAC) (Brazil). The accessions were genotyped with 17 highly polymorphic microsatellite markers. Genetic data were analyzed to determine the genetic structure of the germplasm, quantify its allelic diversity, suggest the composition of a core collection, and discover cases of synonymy, duplication, and misnaming. A total of 304 alleles were obtained, and 334 unique genotypes were identified. The molecular profiles of 145 accessions were confirmed according to the literature and databases, and the molecular profiles of more than 100 genotypes were reported for the first time. The analysis of the genetic structure revealed different levels of stratification. The primary division was between accessions related to Vitis vinifera and V. labrusca, followed by their separation from wild grapevine. A core collection of 120 genotypes captured 100% of all detected alleles. The accessions selected for the core collection may be used in future phenotyping efforts, in genome association studies, and for conservation purposes. Genetic divergence among accessions has practical applications in grape breeding programs, as the choice of relatively divergent parents will maximize the frequency of progeny with superior characteristics. Together, our results can enhance the management of grapevine germplasm and guide the efficient exploitation of genetic diversity to facilitate the development of new grape cultivars for fresh fruits, wine, and rootstock.

Assessment of genetic diversity of cultivated and wild Iranian grape germplasm using retrotransposon-microsatellite amplified polymorphism (REMAP) markers and pomological traits.

Understanding the genetic diversity and relationships between genotypes is an effective step in designing effective breeding programs. Insertional polymorphisms of retrotransposons were studied in 75 cultivated and wild grape genotypes using retrotransposon-microsatellite amplified polymorphism (REMAP) technique. In the morphological part of work, seven pomological traits with a high breeding interest were also analyzed in the cultivated genotypes. A total of 328 markers were produced by 42 primer pairs, out of which 313 markers (95.43%) were polymorphic. Number of markers ranged from 4 in loci Tvv1Fa-873, Vine1-811, Gret1Ra-855 and Tvv1Fa-890 to 12 in locus Vine1Ra-841 with an average value of 7.45. Similarity values based on Dice's coefficient among all 75 grapevine genotypes varied from 0.41 to 0.77. Classification of genotypes using unweighted pair-group method using complete-linkage clustering led to six distinct groups. Some wild and cultivated varieties placed in the same groups. It seems there are close relationship between wild and cultivated genotypes and maybe wild genotypes are ancestor of native grapevines. Grouping of grapevine genotypes based on molecular marker data was not in agreement with clustering by agro-morphological data indicating that the most of multiplied sequences are confined to the non-coding regions of transposon elements. Results showed a substantial level of genetic diversity at molecular and pomological level and the potential of this diversity for future grape breeding programs.

Agronomic performance of seedless table grape genotypes under tropical semiarid conditions

ABSTRACT The Sao Francisco Valley is the main producing region of table grape in Brazil. The objective of this work was to evaluate the agronomic performance and physicochemical characteristics of 14 seedless table grape genotypes to select those with potential to be used in commercial crops in the Sao Francisco Valley, Brazil, or as parents in breeding programs. The experiment was carried out over five crop seasons (2014 to 2018), in Petrolina, PE, Brazil. The treatments consisted of 14 seedless table grape genotypes. The results showed significant effects for all variables evaluated. The highest estimated yield per production cycle were found for ‘Marroo Seedless’ (26.5 t·ha-1), ‘BRS Linda’ (26.4 t·ha-1), ‘CNPUV 23’ (24.9 t·ha-1), ‘A1105’ (24.3 t·ha-1),and ‘A Dona’ (20.2 t·ha-1). Soluble solid (SS) content varied from 13.35 oBrix (‘CNPUV 23’) to 21.63 oBrix (‘A Dona’). The titratable acidity (TA) of the genotypes varied from 0.27 g·100 mL-1 (‘CNPUV 23’) to 0.72 g·100 mL-1 (‘Crimson Seedless’). Principal component analysis showed that the first three principal components explained 81.9% of the data variance, and grouped the best genotypes for production components and fruit chemical composition on different sides of the X-axis. These results allowed the identification of a group of seedless grape cultivars that can be used for commercial crops or as parents for controlled crossings in a local table grape breeding program.

The genetic basis of sex determination in grapes

It remains a major challenge to identify the genes and mutations that lead to plant sexual differentiation. Here, we study the structure and evolution of the sex-determining region (SDR) in Vitis species. We report an improved, chromosome-scale Cabernet Sauvignon genome sequence and the phased assembly of nine wild and cultivated grape genomes. By resolving twenty Vitis SDR haplotypes, we compare male, female, and hermaphrodite haplotype structures and identify sex-linked regions. Coupled with gene expression data, we identify a candidate male-sterility mutation in the VviINP1 gene and potential female-sterility function associated with the transcription factor VviYABBY3. Our data suggest that dioecy has been lost during domestication through a rare recombination event between male and female haplotypes. This work significantly advances the understanding of the genetic basis of sex determination in Vitis and provides the information necessary to rapidly identify sex types in grape breeding programs.

The inheritance of cold tolerance in seven interspecific grape populations

The interspecific cross is an important breeding strategy in grape breeding program. Vitis amurensis is a wild species native to China that can withstand extreme cold temperatures. In this study, we used seven populations of different combinations, and six of these populations are of Vitis amurensis pedigree. The low temperature exotherms (LTEs) were used to evaluate the cold tolerance of grapes, and the results indicated that the cold tolerance inheritance of V. amurensis is very strong and additive and the broad-sense heritability ranged from 0.54 to 0.71 in seven populations. The LTE values distributed in the progeny in a normal, continuous manner despite a wide range of variation, indicating that their presence and concentration is a quantitative trait, controlled by polygenes. In addition, evidence of transgressive inheritance was noted, indicated by the exceptionally high cold tolerance observed amongst some of the progenies. These results are of both practical and scientific interests for further breeding efforts and researches on different cold tolerance in grape.

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

‘BRS Maria Bonita’ is a red seedless table-grape cultivar developed by Embrapa’s grape breeding program. This work aimed to study the influence of rootstock on production components and physico-chemical characteristics of ‘BRS Maria Bonita’ grapes in the tropical conditions of the Sao Francisco Valley. The experiment was carried out in the experimental field of Embrapa Semiarido in Petrolina, PE, Brazil, during five production cycles, using six rootstocks: ‘Harmony’, ‘SO4’, ‘Paulsen 1103’, ‘IAC 572’, ‘IAC 313’ and ‘IAC 766’. The experimental design was random blocks with three replicates. The averages of five production cycles presented statistically significant differences for most variables. Rootstock ‘IAC 766’ increased yield and number of bunches compared with ‘Harmony’ and ‘SO4’. An average of 14.8 t ha(‑1) per cycle and 35 bunches per plant was obtained on ‘IAC 766’. The sizes of the bunch and berry were lower with rootstock ‘SO4’, but did not differ with the other rootstocks. Soluble solids content (SSC) was not influenced by rootstock, reaching mean values of 16.24 °Brix, while the titratable acidity (TA) was higher when the grapes were grafted on ‘SO4’ (0.56 g tartaric acid 100 mL(‑1)) in comparison with ‘Harmony’ (0.45 g tartaric acid 100 mL(‑1)) and’ IAC 313 ‘(0.47 g tartaric acid 100 mL(‑1)). The SSC/TA ratio also did not show differences between rootstocks, ranging from 32.4 (‘SO4’) to 41.8 (‘Harmony’). Rootstock ‘IAC 766’ should be used to increase yield and number of bunches of ‘BRS Maria Bonita’ grown in the Sao Francisco Valley, northeast Brazil.

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.

Postharvest evaluation of cold-hardy table-grape breeding lines

The University of Minnesota grape breeding program has evaluated a small number of cold-hardy cultivars and advanced selections for postharvest storage traits. This is the first experiment for comparing advanced selections to table-grape cultivars for these traits. Nine genotypes were evaluated for cluster weight and fruit chemistry at harvest. Three clusters per genotype were packed in ventilated polyethylene bags and arranged in carton boxes. Paper pads and SO(2) pads were placed on top of the bunches in each carton. The cartons were stored at 2.2°C for 2, 4, 6, and 8 weeks. Clusters were destructively sampled at each storage time point and evaluated for change in fruit weight, berry splitting, berry decay, juice chemistry, and an overall rating of acceptability. An advanced selection, ‘MN1296’, was the top-performing seedless cultivar for overall acceptability for postharvest traits, but has berries that tend to shatter. ‘Louise Swenson’, ‘Swenson Red’, and ‘MN1296’ were rated as the best-performing lines for stem dehydration, in descending order. ‘Swenson Red’ is the largest-fruited Elmer Swenson/UMN cultivar, but has limited commercial planting because of its seeded berries; ‘Swenson Red’ also had no shattering after storage. Berry splitting was worst in ‘Louise Swenson,’ a seeded white grape with multiple uses including wine. ‘Jupiter’ had severe rachis browning after 8 weeks, but little at 2, 4, or 6 weeks, whereas ‘Vanessa’ and ‘MN1369’ both suffered from decay. ‘Jupiter’ and ‘Vanessa’ had the largest clusters, but can be grown in Minnesota with only marginal success using the J-vine training system. Additional research on bud survival and consumer preference will be needed to determine whether any of the advanced selections are suitable for cultivar release.

‘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.