The origin and dissemination of the cultivated almond as determined by nuclear and chloroplast SSR marker analysis

Sixteen nuclear and 10 chloroplast SSR markers were evaluated for 40 almond genotypes including cultivated almond, 18 related species and 5 interspecific-hybrid populations. Results establish the value of SSR (nuclear and chloroplast) markers for distinguishing different genetic lineages and characterize an extensive gene pool available to almond genetic improvement. Hierarchical analysis using integrated nuclear and chloroplast DNA markers support Prunus fenzliana, a species native to the northeast Iran, as a probable ancestor of the cultivated almond. Results also established the importance of interspecific hybridization and subsequent genetic introgression in the development of cultivated almond and demonstrate continuing value of an interspecific gene pool for modern cultivar improvement. Molecular results implicate a dissemination of the cultivated almond from Asia to the Eastern Mediterranean and subsequently the Western Mediterranean and the New World is supported by the molecular analysis of regional germplasm.