The Sicilian Peach (Prunus persica L. Batsch) Germplasm: Evaluation of Genetic Diversity Using SSRs

The decrease in worldwide consumption of peaches due to the poor flavour quality of the fruit has increased the demand for new tasty cultivars. The availability of plant genetic resources is an important prerequisite for improving fruit quality by breeding. In Sicily there is a large collection of local cultivated peaches, whose production fills a niche in the local markets, but which is at risk of disappearing. Their characteristics include highly aromatic fruit and late ripening. Because of their important agronomic characteristics, the Department of Colture Arboree of Palermo University has collected the most interesting accessions to safeguard them and to use the indigenous resources in breeding programmes. To assess the molecular diversity within the Sicilian germplasm, 26 cultivars were screened with 15 SSRs. Eight international cultivars were also included in the analysis as controls. The number of alleles per primer pair ranged from 3 to 10 (mean = 4.7) and 15 cultivars showed a unique fingerprint. The observed heterozygosity was 0.44. Some cases of homonyms and synonyms were found. Furthermore several phenotypically different accessions were indistinguishable at the molecular level, maybe because of the occurrence of co-ancestry and inbreeding. The genetic relationships among the Sicilian cultivars were presented in a dendrogram constructed using the UPGMA method. Clusters reflected their geographical origins.