Habitat features and genetic integrity of wild grapevine Vitis vinifera L. subsp. sylvestris (C.C. Gmel.) Hegi populations: a case study from Sicily

Wild grapevine represents a valuable genetic resource for both future breeding programmes of cultivated grape and conservation of biological diversity in natural environments. In Sicily, the knowledge of this species is quite scarce and fragmentary. Therefore, in order to assess the presence and the genetic quality of wild grapevine in the island, eight populations from different locations were investigated. Their habitats were characterized and the genetic diversity was measured by microsatellite markers in order to evaluate possible relationships between genetic features and the ecological behaviour of populations. With the exception of one population found in a scree-type habitat, all the others were present in flooded areas. Grapevine populations growing in riparian habitats were characterized by low inter- and intra-population variability. Conversely, the scree-type population proved to be the most compact and distinctive, as well as the most genetically isolated. Interestingly, together with other two populations from the northern mountain range of the island, this scree-type grapevine population was genetically rather distant from local domestic accessions, suggesting a weak gene exchange with the cultivated grapevines in Sicily. On the contrary, the other populations showed evidences of probable introgression events, as a result of either gene flow between domestic and wild plants, or of possible secondary domestication/genetic improving processes, based on the use of native wild material.