A database of 502 recent European wheat varieties, mainly of winter type, was constructed using 19 wheat microsatellites and one secalin-specific marker. All datapoints were generated in at least two laboratories using different techniques for fragment analysis. An overall level of >99.5% accuracy was achieved. The 199 alleles detected allowed discrimination between all of the varieties except duplicates, and varieties derived from identical parents. Approximately 25% of the varieties showed some heterogeneities, with the highest level of heterogeneity in south-eastern European material. The highest genetic diversity and the highest number of rare alleles were found in varieties from southern Europe. The relative allele frequencies varied for most microsatellites in different geographical regions.

We have identified 19 QTLs for rachis architecture, a key and complex trait for grapevine production. Fifty out of 1,173 genes underlying these QTLs are candidates to be further explored. In the table grape industry, the rachis architecture has economic and management implications. Therefore, understanding the genetics of this trait is key for its breeding. The aim of this work was to identify genetic determinants of traits associated with the cluster architecture. Characterisations of eight traits was performed on a 'Ruby Seedless' × 'Sultanina' crossing (F1: n = 137) during three seasons, with and without gibberellic acid (GA3) applications. The genotypic effects and the genotype × GA3 interactions were significant for several traits. Rachis length (rl), lateral shoulder length and node number along the central axis were the most prominent traits. On average, the heritability of these traits was ~71 %, with heritability of rl being 76 % as estimated under different seasons. Quantitative trait loci (QTLs) analyses showed that linkage group 5 (LG5) and LG18 harboured the largest number of QTLs for these traits. According to the variance explained, the main QTL (corresponding to rl) was found on LG9. These QTLs were supported mainly by a paternal additive effect and revealed possible pleiotropic effects. Based on the grapevine reference genome, we identified 1,173 genes located under these QTL confidence intervals. Fifty of the 891 annotated genes of this list were selected for their further characterisation because of their possible participation in the rachis architecture. In conclusion, the QTLs detected indicate that these traits and their GA3 responsiveness have a clear genetic basis. Due to the percentage of the total variance explained, they are good candidates to participate in the genetic determination of the cluster architecture.

Background and Aims: Bioactive gibberellins are commonly applied to increase the size of berries in seedless tablegrapes. The genetic determinants for the response of berry size to gibberellic acid (GA3) were investigated in a progeny (n = 137) of Ruby Seedless × Sultanina. Methods and Results: Seed and berry size-related traits were measured at harvest (18°Brix). Heritability was high (∼79%) for all traits under study, especially seed dry mass (>90%). All these traits responded to GA3 and showed interaction between genotype and treatment (g × GA3). Based on quantitative trait loci (QTL) analysis and the grapevine reference genome, we identified about 200 annotated genes located in the corresponding confidence intervals in linkage groups 2 and 18. Nineteen of these genes were selected for further characterisation because of their possible participation in g × GA3.Conclusions: The response to GA3 has an important genetic basis which is given by QTLs localised on linkage groups 2 and 18. Under GA3 treatment, the seed loses its genetic control on berry size given by its major QTLs, indicating a possible interaction between this genetic determinant and GA3. Despite the masking effect, VvAGL11 is associated with the intensity of the response to GA3. Significance of the Study: These results indicate the complex role of g × GA3 at the genetic level in the control of berry size.

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