Vitis vinifera ssp. silvestris: the state of healt of wild italian and spanish populations estimated using nuclear and chloroplast SSR analysis

Genetic relationship among six Italian and four Spanish populations of wild grapevine (Vitis vinifera ssp. silvestris) were investigated using nuclear and chloroplast SSR analysis. Results show that the Italian populations are characterized by high genomic diversity within and among populations, with a peak of heterozygosity (Ho = 0.8419) for a population collected in Southern Italy. The demonstration of high gene flow among the Italian populations suggests a central role for the Italian peninsula as a principal refugial area of wild grapevines during the last glaciation. On the other hand, the low haplotype richness and the high level of genetic distance detected among the Spanish populations combined with their low gene flow shows that these populations suffered from a genetic erosion. Genetic relationship between Italian and Spanish populations was investigated and results showed a clear genetic divergence between the Italian and the Spanish wild grapevines. On the other hand, the Nm values and genetic distances calculated in the case of Sardinia population showed a gene flow value equally with the Italian and the Spanish populations. The genetic structure of Sardinia population suggests a possible connective role for this island in germplasm exchange between Italy and Spain during postglacial recolonization. By providing information on population history, genetic structure and gene flow, and by identifying areas harboring high levels of wild grape variability, this study provides the bases for the preservation of biodiversity of wild grapevine.