Microsatellite DNA polymorphism analysis of clones of Vitis vinifera 'Sangiovese'

Allelic polymorphism at seven microsatellite loci (VVMD5, VVMD6, VVMD7, VVMD8, VVMS2, VVMS4, and VVMS29) was analyzed in 12 clones of Vitis vinifera L. 'Sangiovese', an ancient Italian wine grape cultivar. Eleven of the clones were identical at all seven loci, but one clone (SG 8T) differed from the others by one allele at each of four loci. These data suggest that the eleven identical clones most likely originated from a single seedling progenitor and that SG 8T could be a seedling, parent or sibling of this progenitor. A strict definition of cultivar (monoclonal origin) would require that SG 8T be excluded from 'Sangiovese', but a broader definition, that includes the possibility of polyclonal origin from closely related individuals, is widely accepted in the wine grape research community. If analysis at additional loci confirms the close genetic relationship between SG 8T and the other clones that is suggested by this study, then, by the broader definition, SG 8T might still be included in the cultivar Sangiovese. The ability to detect allelic differences that is afforded by microsatellite analysis may force a clarification of the economic definitions of "cultivar" and "clone" with respect to wine grapes.