Microsatellite fingerprinting of an indigenous grapevine collection.

We report our study on genetic diversity and relationships in an endangered grape germplasm collection using polymorphism at 30 microsatellite loci. A germplasm safeguard programme was set up of grapevine varieties considered as indigenous to North-Eastern Italy. In Italy indeed, as in other Mediterranean countries, grapevine (Vitis vinifera L.) used to be characterized by the diffuse presence of indigenous cultivars, originated through centuries of natural and human selection (Martin et al. 2003, Snoussi et al. 2004). To ensure that allele size of SSRs was properly scored, the SSR marker system relied on a Vitis vinifera microsatellite genotype database. For this purpose we utilized the GENRES#081 (European Network for Grapevine Genetic Resources Conservation and Characterization; This et al. 2004). The genetic profiles of 19 grapevine indigenous varieties, together with seven international ones taken as reference, were searched for possible parentage relationships and several cases of suspected synonyms have been investigated. In the indigenous varieties the number of alleles per locus ranged from two at UDV109, VVIQ61, VVIU37 and VVIV16 loci, to ten at VVMD7 locus, with an average of 4.6 alleles per locus. The native germplasm displayed a greater diversity with an higher proportion of unique alleles compared to international cultivars. This is probably due to a past contribution of wild grapevine to the cultivated genepool. Furthermore all native varieties clustered in the same branch of the UPGMA phenogram thus confirming their local origin. In this research the majority of local cultivars were demonstrated to constitute an independent source of genetic variation, and therefore a possible valuable resource of interesting genetic traits for breeders.