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Background Grapevine reproductive development has direct implications on yield. It also impacts on berry and wine quality by affecting traits like seedlessness, berry and bunch size, cluster compactness and berry skin to pulp ratio. Seasonal fluctuations in yield, fruit composition and wine attributes, which are largely driven by climatic factors, are major challenges for worldwide table grape and wine industry. Accordingly, a better understanding of reproductive processes such as gamete development, fertilization, seed and fruit set is of paramount relevance for managing yield and quality. With the aim of providing new insights into this field, we searched for clones with contrasting seed content in two germplasm collections. Results We identified eight variant pairs that seemingly differ only in seed-related characteristics while showing identical genotype when tested with the GrapeReSeq_Illumina_20K_SNP_chip and several microsatellites. We performed multi-year observations on seed and fruit set deriving from different pollination treatments, with special emphasis on the pair composed by Sangiovese and its seedless variant locally named Corinto Nero. The pollen of Corinto Nero failed to germinate in vitro and gave poor berry set when used to pollinate other varieties. Most berries from both open- and cross-pollinated Corinto Nero inflorescences did not contain seeds. The genetic analysis of seedlings derived from occasional Corinto Nero normal seeds revealed that the few Corinto Nero functional gametes are mostly unreduced. Moreover, three genotypes, including Sangiovese and Corinto Nero, were unexpectedly found to develop fruits without pollen contribution and occasionally showed normal-like seeds. Five missense single nucleotide polymorphisms were identified between Corinto Nero and Sangiovese from transcriptomic data. Conclusions Our observations allowed us to attribute a seedlessness type to some variants for which it was not documented in the literature. Interestingly, the VvAGL11 mutation responsible for Sultanina stenospermocarpy was also discovered in a seedless mutant of Gouais Blanc. We suggest that Corinto Nero parthenocarpy is driven by pollen and/or embryo sac defects, and both events likely arise from meiotic anomalies. The single nucleotide polymorphisms identified between Sangiovese and Corinto Nero are suitable for testing as traceability markers for propagated material and as functional candidates for the seedless phenotype.

Grapevine (Vitis vinifera L. ) was an important crop in the past in Asturias (Northwestern Spain), but the phylloxera and later the boom of the mining industry almost led to its extinction in the last century. Currently, the grape growers are rescuing the old cultivars present in the region from ancient times, but the long period of abandon has originated a lack of information about their characteristics. Four red (‘Albarin Negro’, ‘Carrasquin’, ‘Verdejo Negro’ and ‘Mencia’) and two white (‘Albarin Blanco’ and ‘Godello’) minority grapevine cultivars from Asturias (Spain) were studied for phenology, fertility, vigor, production and berry quality parameters for two consecutive years. Great differences between cultivars were found: ‘Verdejo Negro’ and ‘Albarin Blanco’ had an early budburst both years, ‘Carrasquin’ was the latest harvested, and ‘Albarin Negro’ presented the highest total fertility. ‘Mencia’ had the greatest bunch weight, and, together with ‘Verdejo Negro’, the lowest total acidity and highest pH. Shikimic acid was a varietal marker, its content being higher in ‘Carrasquin’, ‘Verdejo Negro’ and ‘Albarin Blanco’. Significant differences between years in the measured parameters were also found. Agronomical evaluation is the first step to recover these minority cultivars from extinction and to provide to grape growers a deeper knowledge about the characteristics of each cultivar, allowing enriching and diversifying the wine market with different products.

The genetic varietal authentication of wine was investigated according to DNA isolation procedures reported for enological matrices and also by testing 11 commercial extraction kits and various protocol modifications. Samples were collected at different stages of the winemaking process of renowned Italian wines Brunello di Montalcino, Lambruschi Modenesi, and Trento DOC. Results demonstrated not only that grape DNA loss is produced by the fermentation process but also that clarification and stabilization operations contribute to the reduction of double-stranded DNA content on wine. Despite the presence of inhibitors, downstream PCR genotyping yielded reliable nuclear and chloroplast SSR markers for must samples, whereas no amplification or inconsistent results were obtained at later stages of the vinification. In addition, a TaqMan genotyping assay based on cultivar-specific single-nucleotide polymorphisms (SNPs) was designed, which allowed assessment of grapevine DNA mixtures. Once the wine matrix limitations are overcome, this sensitive tool may be implemented for the relative quantification of cultivars used for blend wines or frauds.

Albarin Negro is a red minority grapevine cultivar ( Vitis vinifera L.) grown in Asturias (Spain) that is currently expanding because of its high quality. Considering the capital importance of rootstock in maturation, the effects of five rootstocks (110 R, 196-17 C, 101-14 MG, 3309 C and Rupestris de Lot) on the agronomical and enological characteristics of Albarin Negro were studied for three years. The trial consisted in three repetitions of ten vines for each rootstock. The phenological stages of budburst, flowering and veraison were monitored. Vegetative and production parameters were measured, and berry analysis performed at harvest. The wines subsequently elaborated were analyzed for global parameters, acids, sugars, chromatic characteristics and volatile compounds, and sensorially evaluated. Rootstocks 110 R and 3309 C produced a higher berry yield but they delayed maturation. 101-14 MG had the lowest yield and berry weight. Rupestris de Lot produced a poor berry set, as has been reported in other studies. Wines produced from 196-17 C scored better in sensorial analysis. These results should be taken into account for future plantations.

Palestine has a wide range of agro-ecological concerns and hosts a large variety of plants. Grapes are part of the cultural heritage and provide an indispensable food ingredient. Local cultivars have been traditionally identified on the basis of morphological traits, geographical origin, or names of the vineyard owner; therefore, the occurrence of homonymy, synonymy, and misnaming significantly prevents their valorization. DNA profiling by 22 common SSR markers was used to characterize 43 putative cultivars grown mainly for local table grape consumption at the southern highland regions of West-Bank, to further evaluate genetic diversity and relationships of the population. Consistent matching of SSR markers with grapevines cultivated in neighboring countries or maintained in European germplasm collections was found for 8 of the 21 different non-redundant genotypes discovered, suggesting possible synonyms as well as the occurrence of breeding selections formerly developed in the USA. Genetic relationships inferred from SSR markers clearly assigned Palestinian cultivars to the Proles orientalis subpr. Antasiatica ancestral population, and they even remarked the connection between local resources and cultivars generated from international table grape breeding. This study supports the value of collection and conservation of vines endemic to a region of immense historical importance for viticulture.

The genetic heritage of the Asturian grapevine (Vitis vinifera L.) has been declining over the past century due to the phylloxera attack and the further abandonment of this culture. In addition, efforts in recent years to restore the Asturian vineyard with the pulling-up of old vineyards and replanting with cultivars endorsed by Cangas Quality Wine regulations are contributing even more to this genetic erosion. The aim of this study was the evaluation and identification of the phytogenetic resources of the Asturian grapevine. A total of 293 accessions were collected in old vineyards and analyzed through nine microsatellite markers. Forty-two different genotypes were obtained, including six profiles with allelic variations. Only 27 cultivars were identified when compared with national and international databases; some of them had not been found in this region before. Homonymies and synonymies have also been detected. These results provide an overview of the status of current grapevine phytogenetic resources in Asturias. Despite the substantial genetic erosion that the Asturian vineyard has suffered, a higher variability than expected has been detected. The finding of new grapevine genotypes is a fact of great importance. The genetic grapevine resources are being drastically reduced all over the world, so this new genetic material has to be included in germplasm banks for its conservation and further agronomical and enological evaluation.

International audience; Grapevines (Vitis vinifera L.) form the basis of viticulture, and are susceptible to diseases such as downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator). Therefore, successful viticulture programs require the use of pesticides. Breeding for resistance is the only eco-friendly solution. Marker-assisted selection is currently widely used for grapevine breeding. Consequently, traits of interest must be tagged with molecular markers linked to quantitative trait loci (QTL). We herein present our findings regarding genetic mapping and QTL analysis of resistance to downy and powdery mildew diseases in the progenies of the GF.GA-47-42 ('Bacchus' x 'Seyval') x 'Villard blanc' cross. Simple sequence repeats and single nucleotide polymorphisms of 151 individuals were analyzed. A map consisting of 543 loci was screened for QTL analyses based on phenotypic variations observed in plants grown in the field or under controlled conditions. A major QTL for downy mildew resistance was detected on chromosome 18. For powdery mildew resistance, a QTL was identified on chromosome 15. This QTL was replaced by a novel QTL on chromosome 18 in 2003 (abnormally high temperatures) and 2004. Subsequently, both QTLs functioned together. Additionally, variations in the timing of the onset of veraison, which is a crucial step during grape ripening, were studied to identify genomic regions affecting this trait. A major QTL was detected on linkage group 16, which was supplemented by a minor QTL on linkage group 18. This study provides useful information regarding novel QTL-linked markers relevant for the breeding of disease-resistant grapevines adapted to current climatic conditions.

Aim: Grapevine is a traditional crop in Asturias (northern Spain). However, an important part of the varietal heritage of this region is still unknown. Great biodiversity was reported in previous surveys, with varietal identification being carried out via microsatellite markers. The aim of the present study was to confirm the previous genetic identification and provide the first description of the unknown cultivars.Methods and results: Forty cultivars were described in situ over a two-year period through 58 ampelographic descriptors. A model description was performed for each cultivar and great variability was found : white, red and rosé grape cultivars ; hybrids ; winemaking and dual-use (wine and table grapes) cultivars ; and some teinturier cultivars. Cluster analysis grouped cultivars with similar characteristics.Conclusion: Ampelographic description was complementary to molecular identification in confirming the identity of the studied cultivars. Moreover, unknown cultivars have been described for the first time. Complete characterization is necessary because these cultivars constitute valuable genetic resources for crop breeding programmes.Significance and impact of the study: Considering the limited number of accessions of the unknown cultivars and the replanting of old vineyards with vines approved by Cangas Quality Wine regulations, their conservation and study is vital to provide genetic resources for potential breeding or technological purposes in the future.

The mountainous region between the Caucasus and China is considered the center of diversity for many temperate fruit crops. Also the transitional types of grapes, including wild forms of the subsp. Vitis sylvestris, cultivated landraces and ancient local varieties, were once common in this region. Despite Central Asia is considered a focal region of the world regarding grapevine development, limited information about the extent and distribution of grapevine genetic variation is available. Here we report the first assessment of genetic diversity, relationships and structure of 80 grapevine cultivars and 21 V. sylvestris accessions originated from the regions of Uzbekistan, Tajikistan and Kyrgyzstan. We expanded the coverage of this survey to include a set of 53 traditional Georgian varieties and homologous SSR genotypes of 107 cultivars representing four V. vinifera ancestral subpopulations. This allowed us to evaluate the contribution of the Central Asian grapevine germplasm to diversification of the cultivated grapevine gene pool., VITIS - Journal of Grapevine Research, Vol. 54 (2015): Vitis (Special Issue)