Financial support: The present work has been done in the framework of a research programme (1997-2001) developed in the area of viticulture and wine making funded by the Tuscan regional authority ARSIA (Agenzia Regionale per lo Sviluppo e l'Innovazione nel Settore Agricolo-Forestale).

Keywords: clone variation, polymerase chain reaction, sequence tagged sites, variety identification.

Abbreviations: PCR, polymerase chain reaction; AFLP, amplified fragment length polymorphism; Cy5, Cy^TM5 amidite (5'-cyamine-d[seq]) fluorochrome technology.

Microsatellite polymorphism analysis on 25 different "Sangiovese" accessions was carried out at eight microsatellite loci (VVS2, VVS4, VVS29, VVMD3, VVMD6, VVMD7, VVMD17 and VVMD21). In order to evaluate variability within the "Sangiovese" variety and to confirm variety identification, genotype analysis, allele distribution and pedigree information were processed with a DNA-automated sequencer running AlleleLinks software.

DNA typing revealed three cases of genetic dissimilarity compared to registered "Sangiovese" clones and the divergent accessions thought to be different clones of the same variety. The divergent accessions were different from "Sangiovese" at four microsatellite loci (VVS2, VVS4, VVMD7 and VVMD21). An innovative non-radioactive modification of AFLP genome profiling confirmed the data obtained by microsatellite amplification test. These results underline the importance of biotechnological testing, such as the PCR-based DNA tests together with traditional ampelography, in Vitis vinifera L. clone and variety selection programmes to avoid misnaming and erroneous identification and to evaluate genetic relatedness and variability within populations.