Genetic similarities among wine grape cultivars revealed by restriction fragment-length polymorphism (RFLP) analysis

RFLP data were used to assess genetic similarity among 33 Vitis vinifera L. cultivars and one interspecific cultivar. A similarity matrix was constructed on the basis of the presence or absence of 49 bands generated by eight RFLP probes and cluster analysis was performed. The mean similarity index for all pairwise comparisons was 0.696 and ranged from 0.444 between 'St. Emilion' and the interspecific hybrid 'Salvador' to 0.952 between 'Chenin blanc' and 'Semillon'. Mean similarity among all V. vinifera cultivars was 0.705. Several groupings of similar cultivars are consistent with historical reports and presumed geographic origins: 'Chardonnay' and 'Melon', 'Colombard' and 'Folle blanche', 'GeWurztraminer' and 'Trousseau', 'Cabernet franc' and 'Cabernet Sauvignon', 'Mission' and 'Palomino', The similarity between 'Mission' and 'Palomino' is the first genetic evidence to support the putative Spanish origin of 'Mission'. Some groupings are unexpected ('Sauvignon blanc' and 'Gewurztraminer', 'Chenin blanc' and 'Semillon') because the cultivars are not thought to have originated in the same regions. While some relationships suggested by this study may be artifacts of RFLP analysis or of the statistical method, they raise questions for further genetic inquiry into the origins of grape cultivars.