Genetic diversity and relationships among Italian and foreign almond germplasm as revealed by microsatellite markers

Italian germplasm is characterized by a wide diversity rapidly developed determining a massive genetic pool of cultivars in several growing areas. On the whole, regions of southern Italy, and in particular Sicily, were considered as one of the main trade routes along which almond was spread throughout the shores of the Mediterranean Sea. In this work, 9 SSR markers have been used to analyze 113 almond cultivars and accessions coming from ex-situ conservation, including most of almond genotypes spread in Sicily and Apulia and foreign cultivars from Mediterranean, American and Australian areas in order to determine the level of genetic diversity within Italian genotypes and elucidate phylogenetic and possible parentage relationships between Italian accessions and foreign germplasm. Distance and model-based analyses revealed a high level of variability both among and within geographical areas. In total, 159 alleles were detected altogether, which identified the average of 44 genotypes in the population investigated. The wide genetic diversity detected in the Italian almond cultivars represents a valuable source of variability to be applied for breeding. These data represent the first overview of genetic diversity among Italian almond cultivars using molecular markers.