Genetic diversity in ancient apple germplasm from northwest Italy

36 apple (Malus × domestica Borkh.) cultivars belonging to local germplasm of the Piedmont Region (northwest Italy), together with eight commercial cultivars, were analysed using nine microsatellite [simple sequence repeat (SSR)] markers, chosen from a set of previously described SSRs isolated in Malus. The aims of the research were to determine genetic identities, to estimate genetic diversity, and to identify genetic relationships between the 44 accessions. A high level of variation was detected, with a mean of 10.9 alleles per locus. The mean observed heterozygosity was 0.82 (range = 0.43 – 0.98). Of the 44 cultivars studied, 17 were triploid. Triploidy was particularly common in the ‘Renetta’ group. The selected loci showed 36 genetic profiles, suggesting the existence of possible synonyms. Two cases of homonymy were also found, and the genetic relationships between cultivars are discussed considering historical records regarding their origins.