Grape Breeding Programs Research Articles

Comparative transcriptomics of Central Asian Vitis vinifera accessions reveals distinct defense strategies against powdery mildew.

Grape powdery mildew (PM), caused by the biotrophic ascomycete Erysiphe necator, is a devastating fungal disease that affects most Vitis vinifera cultivars. We have previously identified a panel of V. vinifera accessions from Central Asia with partial resistance to PM that possess a Ren1-like local haplotype. In this study, we show that in addition to the typical Ren1-associated late post-penetration resistance, these accessions display a range of different levels of disease development suggesting that alternative alleles or additional genes contribute to determining the outcome of the interaction with the pathogen. To identify potential Ren1-dependent transcriptional responses and functions associated with the different levels of resistance, we sequenced and analyzed the transcriptomes of these Central Asian accessions at two time points of PM infection. Transcriptomes were compared to identify constitutive differences and PM-inducible responses that may underlie their disease resistant phenotype. Responses to E. necator in all resistant accessions were characterized by an early up-regulation of 13 genes, most encoding putative defense functions, and a late down-regulation of 32 genes, enriched in transcriptional regulators and protein kinases. Potential Ren1-dependent responses included a hotspot of co-regulated genes on chromosome 18. We also identified 81 genes whose expression levels and dynamics correlated with the phenotypic differences between the most resistant accessions ‘Karadzhandahal’, DVIT3351.27, and O34-16 and the other genotypes. This study provides a first exploration of the functions associated with varying levels of partial resistance to PM in V. vinifera accessions that can be exploited as sources of genetic resistance in grape breeding programs.

Armenian grapevines: cytoembryological, morphological and chemical analysis

The objectives of our study was to phenotype Armenian grapevines on the base of cytoembryological, morphometric and phenolic content analysis of 10 wine and 10 table cultivars (Vitis vinifera L.). The presented results suggest that Armenian table grape cultivars have higher level of abnormalities in the process of seed formation than wine cultivars. However, during ovule development, the observed differences between table and wine varieties were not significant. The berry morphometric analysis demonstrated that table cultivars formed significantly larger and heavier berries than wine cultivars. The obtained results show that wine grapes contained significantly higher phenol concentrations than table grapes, in both colored and white grapevine cultivars. The study of phenol composition, an important chemical descriptor in grapevine phenotyping, provides oenological information useful to improve the wine quality. Cultivar characterization could be used as marker for the selection of table and wine grape breeding programs. These results will be upgraded in the database for Armenian grapevine varieties. In future Armenian germplasm will be compared with datasets of neighboring countries, to determine the varietal origins relationships.

Adaptation of leaves of Vitis vinifera L. to seasonal drought as affected by leaf age

Thermoluminescence (TL) glow curves were recorded from leaves of eight Vitis varieties grown in South-West India, viz. Thompson Seedless, Sonaka, Anab-E-Shahi, Kishmish Chami, Tas-A-Ganesh, Black Monuka, Bangalore Purple and American Dogridge belonging to the Vitis vinifera, V. labrusca and V. champini species. The TL peaks were analysed, using a computer-assisted model based on the general order kinetics theory, to determine thermodynamical parameters such as activation energy, entropy, frequency factor and free energy. It was observed that all six V. vinifera samples showed an entirely different TL pattern consisting of only one prominent and highly narrow peak at around -5 °C (peak II). The prominance oft this peak attributed to S 2 /S 3 Q a · recombination suggests a modification at the plastoquinone electron acceptor sites. On the other band, the remaining two varieties Bangalore Purple and American Dogridge showed broader TL spectra consisting of a higher number of peaks. This basic difference is attributed to the difference in species of the selected varieties. Moreover, the TL recorded from Bangalore Purple resembled the standard TL spectra of spinach. The study undertaken in this paper may be relevant in grape breeding programs.

PRELIMINARY EVALUATION OF SOME GRAPE CULTIVARS (VITIS VINIFERA) GROWN IN THE TARBIAT MODARES UNIVERSITY (TMU) COLLECTION VINEYARD

There are a wide range of grape (Vitis vinifera) cultivars and clones grown in different macro- and microclimatic conditions of Iran that produce high quality fruit. Grape germplasm in Iran is known to exhibit good diversity in seeded and unseeded fruit, and in berry size, shape and color of the skin, as well as in berry flesh color, and is rich in various physiological and pomological characters. This germplasm provides a good gene pool and excellent working material for specific breeding objectives. Studying various characters of this germplasm in relation to cultivar/clone names is needed to determine synonyms for the different planting regions of Iran is an important task in grape breeding programs as well as in vineyard establishment. The aim of the present research was to identify the name and monitor morphological grapevine and fruit characteristics of some cultivars/ clones within the Tarbiat Modares University (TMU) grape collection vineyard. Six cultivars were identified with different fruit maturity attributes. There are early, mid- and late season maturing grape cultivars in the vineyard with low to high total soluble solid (TSS) at the time of harvest. According to the results and based on the TMU breeding objectives, details on the grapevine as well as fruit characteristics will be discussed.

Transcriptome characterization of three wild Chinese Vitis uncovers a large number of distinct disease related genes

BackgroundGrape is one of the most valuable fruit crops and can serve for both fresh consumption and wine production. Grape cultivars have been selected and evolved to produce high-quality fruits during their domestication over thousands of years. However, current widely planted grape cultivars suffer extensive loss to many diseases while most wild species show resistance to various pathogens. Therefore, a comprehensive evaluation of wild grapes would contribute to the improvement of disease resistance in grape breeding programs.ResultsWe performed deep transcriptome sequencing of three Chinese wild grapes using the Illumina strand-specific RNA-Seq technology. High quality transcriptomes were assembled de novo and more than 93% transcripts were shared with the reference PN40024 genome. Over 1,600 distinct transcripts, which were absent or highly divergent from sequences in the reference PN40024 genome, were identified in each of the three wild grapes, among which more than 1,000 were potential protein-coding genes. Gene Ontology (GO) and pathway annotations of these distinct genes showed those involved in defense responses and plant secondary metabolisms were highly enriched. More than 87,000 single nucleotide polymorphisms (SNPs) and 2,000 small insertions or deletions (indels) were identified between each genotype and PN40024, and approximately 20% of the SNPs caused nonsynonymous mutations. Finally, we discovered 100 to 200 highly confident cis-natural antisense transcript (cis-NAT) pairs in each genotype. These transcripts were significantly enriched with genes involved in secondary metabolisms and plant responses to abiotic stresses.ConclusionThe three de novo assembled transcriptomes provide a comprehensive sequence resource for molecular genetic research in grape. The newly discovered genes from wild Vitis, as well as SNPs and small indels we identified, may facilitate future studies on the molecular mechanisms related to valuable traits possessed by these wild Vitis and contribute to the grape breeding programs. Furthermore, we identified hundreds of cis-NAT pairs which showed their potential regulatory roles in secondary metabolism and abiotic stress responses.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1442-3) contains supplementary material, which is available to authorized users.

Patterns of SNP distribution provide a molecular basis for high genetic diversity and genetic differentiation in Vitis species

Grape (Vitis L.) is one of the most economically valuable fruit crops in the world. The molecular basis for high genetic diversity and genetic differentiation thus conferring broad adaptability in the Vitis genus remains elusive. Genetic patterns in Vitis were comprehensively characterized by re-sequencing of 6862 nuclear SNPs in this study. Nucleotide diversity (π = 0.0073), genetic differentiation (pairwise differences, 0.24) and SNP variation in Vitis species were relatively high compared to most woody plant species. Molecular variance among accessions within species (FIS = 0.369) and among 30 species (FST = 0.511) suggested strong population structure in Vitis (P 95 %) of minor SNPs to engender high differentiation among species thus high genetic diversity in the whole genus. This confers potentially broad adaptability thus a broad base for natural selection in this genus. Species from three geographical regions were discerned into independent quadrants in the principle coordinate analysis (PCoA) plot and their clustered patterns suggested that their molecular identities represented geographical origins of Vitis species. Species extinction will be an irreversible loss for breeding and genetic conservation. Species with low diversity, low heterozygosity, and high agronomical value should be given priority for conservation. Survey of species-specific SNPs will facilitate germplasm conservation and grape breeding programs. This study greatly adds to our knowledge of genetic patterns and molecular bases for ecological habits of Vitis species and provides valuable information for germplasm conservation and utilization, and grape breeding.

DEVELOPMENT OF MOLECULAR MARKERS FOR POWDERY MILDEW RESISTANCE IN GRAPEVINES

Molecular markers linked to disease resistance can be used to pyramid resistance genes for improved durability and to improve the efficiency of evaluation. To develop molecular markers linked to resistance to grape powdery mildew (Erysiphe necator), Vitis romanetii was used to create a pseudo-backcross 2 mapping population by crossing C87-41 ((V. romanetii × V. vinifera) × V. vinifera) with B70-57 (V. vinifera). Resistance was assessed in multiple locations and years by both natural and artificial inoculation. A genetic map was constructed using 101 SSRs and 28 SNPlex markers. This source of disease resistance is qualitative, fits a single-resistance gene model, and was mapped to the Ren4 locus on chromosome 18. Two markers, VMC7f2 and SNPlexE1M4R1 were shown to be tightly linked to powdery mildew resistance and seedlessness. Together they will be a valuable tool for marker assisted selection in table grape breeding programs.

TABLE GRAPE BREEDING AT THE ARC INFRUITEC-NIETVOORBIJ, SOUTH AFRICA; ITS IMPACT ON THE SA INDUSTRY AND LATEST DEVELOPMENTS

Since its inception in 1952 and first releases in 1965, the ARC table grape breeding program released a total of 28 cultivars. In 1985 one ARC cultivar (?Bien Donne?) made a noteworthy contribution to export (3%), while the contribution of six ARC cultivars was 25,9% of the total export in 2006. Changes in consumer preferences necessitate regular revision of aims. For example, export of seedless cultivars from SA grew from a minimal contribution in 1985 to over 52% in 2006 and is still growing. New seedless cultivars are developed by in vitro embryo rescue techniques, while crosses to develop seeded cultivars with unique characteristics are also made. The first seedless cultivar was released in 1986, followed by another five seedless cultivars. Two new, early ripening, red seedless cultivars will be released in the near future to the SA industry. Since 2004, DNA technologies and molecular approaches were introduced as an essential component of the disease resistance breeding program. An extensive DNA fingerprint of table grape cultivars/selections was constructed and is used to solve identity issues. ?Regent?, an interspecies hybrid, is resistant to powdery and downy mildew (Fisher et al., 2004) and was used to introduce resistance into the ARC table grape breeding program. We report validation of the resistance loci previously identified, following a QTL approach in a ?Regent? × ?RedGlobe? population. We identified plants that phenotypically displayed resistance to both downy and powdery mildew, whilst also carrying flanking markers for both resistance QTL. These plants are prime candidates to be used in future crosses to introduce resistance, whilst also selecting for good fruit quality. The population and the genetic map is a valuable resource that can be used in future to map other disease resistance loci present in Regent or fruit quality traits of ?RedGlobe?.

Development of user-friendly functional molecular markers for VvDXS gene conferring muscat flavor in grapevine

High fruit and wine quality combined with good climatic adaptation and disease resistance are essential objectives of grape breeding. While several molecular markers are available for pyramiding resistance to fungal pathogens, molecular tools for predicting fruit composition are still scarce. Muscat flavor, caused by the accumulation of monoterpenoids in the berry, is an important target trait for breeding, sought after in both table grapes and wine. Four missense mutations in the VvDXS gene in grape germplasm have been shown to be tightly linked to muscat flavor. Here we present highly reproducible and breeder-friendly functional markers for each of the targeted polymorphisms developed by using either the multiplexed minisequencing SNaPshot™ method, the high-resolution melting (HRM) assay or the cleaved amplified polymorphic sequence system. A total of 242 grapevine accessions were analyzed to optimize these different genotyping methods and to provide allele-specific markers for accurate selection of muscat flavor at early stages of grape breeding programs. The HRM and the minisequencing SNaPshot multiplex assays allow for high-throughput automated screening and are suitable for large-scale breeding programs and germplasm characterization.Electronic supplementary materialThe online version of this article (doi:10.1007/s11032-013-9929-6) contains supplementary material, which is available to authorized users.

‘Iniagrape-one’, a New Chilean Table Grape Cultivar

‘Iniagrape-one’ (Vitis vinifera L. 3 Vitis vinifera L.) is a new and distinct midseasonripening, blue–black table grape cultivar for export markets that stores well for up to three months under the proper conditions. This cultivar presents large clusters and firm large berries with seed rudiments. This cultivar was released by the Table Grape Breeding Program at La Platina Experiment Research Center of the Agricultural Research Institute (INIA). It provides a black cultivar adapted to three growing regions in Chile and fulfills a niche market for black grapes. ‘Iniagrapeone’ fills the harvest period between the current commercial black cultivars and expands the shipping period for black grapes for the Chilean harvest season. ‘Iniagrape-one’ is harvested in mid-February in the central area of Chile (Aconcagua Valley), which is 1 week after ‘Black Seedless’ and ‘Midnight Beauty’ and 3 weeks before ‘Autumn Royal’. It also ripens by the second week of January under warm and dry growing conditions such as those found in northern Chile (Elqui Valley).

EVALUATION OF BERRY QUALITY TRAITS IN F1 PROGENY DERIVED FROM THE CROSS 'MUSCAT HAMBURG' × 'SUGRAONE SEEDLESS' (VITIS VINIFERA)

The common objective of most grape breeding programs is to produce locally adapted, high yielding cultivars with a quality that is suited for the intended use, with special emphasis on the time of ripening, colour, sugar and acid content, special aromas, as well as loose clusters and big berries. In this paper, the berries from a population of 93 plants derived from controlled crosses between the cultivars 'Muscat Hamburg' (MH, female progenitor) and 'Sugraone' (SS, male progenitor) are characterised. MH berries are dark violet, small and soft, with seeds and an intense muscat taste. On the other hand, SS is a very early maturing seedless cultivar with yellow crispy berries. For the table grape progeny, 93 hybrids were established under production and three replications of each hybrid were collected and evaluated during the 2005 and 2006 seasons. The parameters considered were: total and individual anthocyanin monoglucosides (delphinidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, peonidin 3-glucoside and malvidin 3-glucoside), sugars (sucrose, glucose and fructose) and organic acids (tartaric and malic acids). The results were analysed using the Kolmogorov-Smirnov test in order to determine the type of distribution. The parametric Student test and non-parametric Wilconson test were applied to detect the year effect on metabolite concentrations. Spearman and Pearson tests were used for correlation analysis. Glucose, fructose, tartaric and malic acids followed a normal distribution, while total and individual anthocyanins and sucrose followed a non-normal distribution during the two years of study. Significant inter-annual differences were found between the values for the two years for cyanidin-3-glucoside, glucose, fructose, sucrose and malic acid. Finally, statistically significant correlation (p<0.001) between both years was observed for all the parameters, except glucose and fructose concentration.

Inheritance of anthocyanin content in the ripe berries of a tetraploid × diploid grape cross population

Variation patterns and inheritance of anthocyanin content in the ripe berries of a tetraploid × diploid table grape cross population were investigated in two successive years. The population segregated for three different ploid levels: dipolids, triploids, and tetraploids. A total of 28 different anthocyanins were detected and quantified in the progeny population. Transgressive segregation for the total anthocyanin content was observed in all the three ploid progeny populations. The total anthocyanin content increased as the ploid level increased. The broad sense heritabilities (H2) of the total anthocyanin content were all relatively high, ranging from 0.53 to 0.98, 0.57 to 0.97 and 0.43 to 0.94 in the diploid, triploid and tetraploid population, respectively. Our results suggested that the total anthocyanin content followed an additive inheritance model in this polyploid segregation population. We also observed that the relative contribution of individual anthocyanins to the total anthocyanin content varied significantly among different ploid populations, suggesting that genetic background has important impact on the accumulation of the individual anthocyanin compounds. These results will help develop better breeding strategies in a polyploid table grape breeding program for improving the content of anthocyanins, an important class of polyphenolics possessing antioxidant activities and many other health-related benefits.

Estimates of genotypic and yearly variations on fruit quality and functional traits for tetraploid table grape breeding

We estimated genetic and environmental variance components for fruit quality traits (cluster weight, berry weight, soluble solids content, total sugar content, sugar composition, free acid content, total amino acid content, amino acid composition), and a functional trait (gamma-aminobutyric acid (GABA) content) of three commercial tetraploid table grape cultivars (Kyoho, Pione, Suiho) grown in Japan over three successive years. ANOVA showed that the effect of genotype was significant (P < 0.05) for all traits except soluble solids content and total sugar content. The effect of the year was significant for all traits except amino acid composition (γ ratio) and GABA content. The variance of genotype (σ g 2 ) was highest for γ ratio (63.6%), high in sugar composition (α ratio, 60.3%) and GABA content (58.8%), and negligible for soluble solids content (0.0%) and total sugar content (0.0%). The variance of among years (σ y 2 ) was very high in soluble solids content (82.8%), high in total sugar content (60.2%) and negligibly small in γ ratio (8.7%) and GABA content (6.4%). Some effects of genotype × year interaction, among vines within genotypes, and vine × year interaction were statistically significant, but these components were negligibly small. Except for soluble solids content and total sugar content, significant varietal differences in the traits were recorded. Variance estimates for each trait provides useful information for optimal yearly repetition to effectively discriminate genetic differences in fruit quality and functional traits for improving future tetraploid table grape breeding programs.

Genetic diversity in table grapes based on RAPD and microsatellite markers

The objective of this work was to analyze the genetic diversity of 47 table grape accessions, from the grapevine germplasm bank of Embrapa Semiárido, using 20 RAPD and seven microsatellite markers. Genetic distances between pairs of accessions were obtained based on Jaccard's similarity index for RAPD data and on the arithmetic complement of the weighted index for microsatellite data. The groups were formed according to the Tocher's cluster analysis and to the unweighted pair‑group method with arithmetic mean (UPGMA). The microsatellite markers were more efficient than the RAPD ones in the identification of genetic relationships. Information on the genetic distance, based on molecular characteristics and coupled with the cultivar agronomic performance, allowed for the recommendation of parents for crossings, in order to obtain superior hybrids in segregating populations for the table grape breeding program of Embrapa Semiárido.

Resistance to Elsinoë ampelina and expression of related resistant genes in Vitis rotundifolia Michx. grapes.

Muscadine grapes (Vitis rotundifolia Michx) are considered as excellent genetic resources for grape breeding programs as they are known for their hardiness and resistance to pests and diseases. However, contrary to popular belief, our study indicated that not all muscadine cultivars are resistant to anthracnose disease. In order to identify a source of genetic tolerance towards anthracnose among muscadine cultivars, a series of in-situ and ex-situ experiments were conducted through strict and sensitive screening processes. Two consecutive years of field evaluation of 54 grape cultivars showed various levels of anthracnose incidence among the cultivars between a scale of 0 (tolerant) to 5 (highly-susceptible). Resistance bioassay by inoculation of different spore densities of Elsinoë ampelina on 40 cultivars presented similar results and was consistent with those obtained from the field test. A real-time PCR analysis was conducted to investigate differences of gene expression between susceptible and tolerant cultivars and to confirm results by phenotypic identification. Expression of genes encoding chalcone synthase, stilbene synthase, polygalacturonase-inhibiting protein, chitinase and lipid transfer-protein was only detected in tolerant cultivars. Resistant muscadine cultivars identified in this study could be excellent candidates for grape disease resistance breeding programs.

TOWARDS THE DEVELOPING OF WELL ADAPTED GRAPES FOR TROPICAL REGIONS

The association between proper pruning and irrigation practices has made it possible to grow grapes (Vitis spp.) in tropical regions. Under these conditions, however, the physiological and sanitary behavior of most commercial varieties introduced from traditional temperate regions can be quite different. As a general rule, vegetative growing and yields are not stable. Besides, production costs are also higher as a result of the adoption of an intensive program of chemical interventions. The breeding program maintained by Embrapa Grape and Wine has been using Vitis genetic variability to contribute to the solution of problems resulting from lack of adaptation of traditional grape varieties. About 3,000 hybrids from crossings between several Vitis species, including wild tropical ones, are evaluated every year. Selected individuals are multiplied and evaluated on selection fields for 3-4 years. To be sure about these results, promising selections are propagated and a greater plot is evaluated for more 3-4 years. Depending on the purpose, this step can include sensorial analysis of table grapes, juice or microvinifications. Advanced selections are then tested on real yield conditions or commercial fields, for about 2 years. New cultivars are released only when this decision is also supported by growers. Usually, grape selection prerequisites are quality for processing or table, resistance to main diseases, particularly downy mildew (Plasmopara viticola) and powdery mildew (Uncinula necator), and bud fertility. The grape breeding program is using biotechnology tools as tissue culture, especially embryo rescue for the developing of seedless table grapes, and molecular markers also. In the last years, five processing cultivars ('Moscato Embrapa', 'BRS Lorena', 'BRS Rubea', 'BRS Cora' and 'BRS Violeta') and three seedless table cultivars ('BRS Morena', 'BRS Clara' and 'BRS Linda') released by the program are presenting good performance in tropical conditions. Currently, about 200 table and processing advanced selections are under evaluation.

Use of Genetic Markers to Assess Pedigrees of Grape Cultivars and Breeding Program Selections

In a plant breeding program, an accurate understanding of pedigrees provides useful guidance for future hybridizations. However, plant breeder records occasionally contain errors which may mislead future breeding efforts, and there is considerable value in independently testing reported pedigrees. In this project, SSR markers were used to confirm or correct pedigrees for grape varieties from the Cornell breeding program and a few key varieties used as parents. As expected, most (20 of 24) reported pedigrees were confirmed. Recognizing a heritable null allele from Ontario, at VVMD25, was necessary for parent progeny analysis of several varieties. Suffolk Red and Glenora were shown to be progeny of Black Kishmish and not Black Monukka. The advanced selection NY63.0970.07 is a hybrid of Pinot noir, not Gamay, x Chancellor. Vignoles (Ravat 51) is not descended from the reported parentage of Seibel 6905 x Pinot noir.

Use of Molecular Markers to Correct Grape Breeding Errors and Determine the Identity of Novel Sources of Resistance toXiphinema indexand Pierce’s Disease

Over the past 15 years, the grape breeding program at the University of California, Davis, has been evaluating <i>Vitis rupestris</i> x <i>Muscadinia rotundifolia</i> selections for resistance to the dagger nematode, <i>Xiphinema index</i>, and to Pierce’s disease (PD). Selections from these crosses exhibit very strong resistance to <i>X. index</i> and PD. In addition to breeding efforts, populations from these crosses have been used to develop genetic maps and locate resistance loci. Genetic mapping efforts recently began incorporating SSR markers to refine and expand existing maps. The use of SSR markers revealed that the mapping population parents were not crosses of <i>V. rupestris</i> x <i>M. rotundifolia</i>. This discovery led to testing of the entire group of 161 <i>V. rupestris</i> x <i>M. rotundifolia</i> progeny. All possible male parents surrounding the <i>V. rupestris</i> female parents in the vineyard where the crosses were made were genetically fingerprinted with up to 15 SSR markers to determine the true male parents. Results indicated that most of the male parents were from collections of forms of <i>V. arizonica</i> gathered in Mexico in 1961. These now correctly identified selections represent novel sources of very strong resistance to <i>X. index</i> and PD.

Selection of powdery mildew resistant and susceptible grapevine genotypes with molecular markers

Incorporation of competitive quality and resistance against the most important fungal diseases (powdery and downy mildew) in a cultivar is one of the most important aims of grapevine breeding. In the 20th century, the most advanced results in grapevine resistance breeding were achieved by French researchers. They used resistant cultivars in more than 30% of their growing areas. In these varieties, North American wild Vitisspecies were the resistance gene sources. The discovery of immunity-like resistance of Muscadinia rotundifolia opened new perspectives in resistance breeding. M. rotundifolia harbours a dominant powdery mildew gene, providing resistance in highquality cultivars after back-crosses with V. vinifera varieties. M. rotundifolia has been involved in the Hungarian grape breeding programs since 1996, thanks to a French-Hungarian variety exchange. In addition to traditional selection methods, application of MAS (Marker Assisted Selection) based on various types ofmolecular markers, can provide additional tools for these efforts. Run1 locus, responsible for powdery mildew resistance, was identified in Muscadinia rotundifolia. Molecular markers closely linked to this locus are very significant in screening progenies deriving from M. rotundifolia and V. vinifera crosses, making possible the discrimination between resistant and susceptible genotypes at DNA level. In our analyses BC5 progeny of {(M. rotundifola×V. vinifera) BC4}×Cardinal (V. vinifera) tested for powdery symptoms were analysed with PCR-RFLP (GLP1- 12P1P3) and microsatellite markers (VMC4f3.1, VMC8g9). Our results proved the applicability of the linked markers and reliability of marker assisted selection.

ISELA-INIA, Nueva Variedad de Uva de Mesa

A B S T R A C T Isela-INIA is a mid season ripening table grape (Vitis vinifera L.) cultivar released by the Table Grape Breeding Program at the La Platina Research Centre of the National Agricultural Research Institute, Santiago, Chile. The berries are medium-sized, seedless, green, firm and flavor-full. Giberellic acid combined with girdling can be employed for thinning so as to increase berries size. It usually shows two clusters per shoot, so one cluster can be removed. Some shoulders must be removed in order to improve fruit presentation; this thinning must be done before the veraison, to avoid bruising. It ripens before ‘Thompson Seedless’. Post harvest life in good conditions can last up to 45 days at 0oC.