Renewal of wild grapevine (Vitis vinifera L. subsp. sylvestris (Gmelin) Hegi) populations through sexual pathway : some Italian case studies

Wild Euro-Asiatic grapevine (Vitis vinifera L. subsp. sylvestris (Gmelin) Hegi) is an opportunistic liana with reproductive patterns characterized both by vegetative propagation and sexual reproduction. Vegetative propagation would ensure a rapid vine regeneration and land colonization, while sexual reproduction would assure genetic recombination and chromosome re-assortment crucial for evolution and survival of the species. The aim of this study was the analysis of the parentage relationships within and between fourteen Italian wild grapevine populations, in order to characterize the natural mating system of this taxon. Beside parentage relationship analyses, the estimation of genetic diversity, genetic distance and genetic differentiation were assessed. The populations showed a good extent of genetic diversity and low levels of genetic distance and isolation between them, indicating gene flow among sites. This result was supported by parentage relationships between different populations. Nevertheless, populations from North Italy showed the lowest genetic diversity, while internal relatedness and inbreeding estimation values were higher than the populations from Central and Southern Italy. One of the northern populations resulted particularly high in inbreeding intensity. The parentage relationship analysis pointed out in all sites a, sometimes active, sexual reproduction within populations. Seed dispersal by frugivorous vectors among neighbouring sites seemed less frequent and depending on specific environmental circumstances.