Vineyards genetic monitoring and Vernaccia di San Gimignano wine molecular fingerprinting

The definition of the genetic profile of Vernaccia di San Gimignano (VSG) in the areas of production is an essential step for both the implementation of a plan of analytical traceability and the evaluation of the biological future potential of the same grape variety in relation to any environmental change. The genetic variability of the VSG was monitored by use of SSRs genotyping of a representative portion of individuals belonging to both the productive vineyards and the germplasm collections that represent the “mother plants” reservoir for future vineyards. 74% of the individuals have been shown to be identical to the grapevine genotype reported in databases as VSG truetype. In order to determine the wine varietal composition by DNA analysis, four wine types commercialized as VSG were DNA-tested at 14 loci SSRs. The molecular data obtained demonstrate the presence as prevalent component of the VSG in the four wine types. All the wines revealed the presence of minor varieties, whose presence/absence was estimated by extrapolating the allele configuration that best matched to a standard genotype. Molecular data allow us to exclude the presence of three aromatic white grapevines that are not allowed by the actual production rules (Disciplinare di Produzione).