Molecular characterization of variability and relationships among seven cultivated and selected wild species of Prunus L. using amplified fragment length polymorphism

Analysis of genetic variability and differentiation within and among seven cultivated species and seven wild species of Prunus using amplified fragment length polymorphism revealed four well-supported groups corresponding to the four sections Amygdalus, Armeniaca, Cerasus and Prunophora described within the genus. The section Armeniaca showed significant differentiation from its sister section Prunophora within the subgenus Prunus. Within-species estimates of molecular variation indicated that apricots (0.0529) were the most variable among the species assayed followed by hexaploid plums (0.0359), almonds (0.0330), cherries (0.0310), and diploid plums (0.0303) with moderate levels of variability and peaches (0.0263) were the least variable. The overall distribution pattern of molecular variation within the genus indicated that about 32% of the total variance was accounted for by the within-species variance component, irrespective of partitioning based on either sections or subgenera. The remaining 68% of the variation found among species was hierarchically structured between components due to differentiation among species within and among sections (17.02 and 50.81%, respectively) or among species within and among subgenera (29.53 and 39.05%, respectively). Although cluster and principal components analyses indicate that the gene pools corresponding to the four sections to be homogenous, partitioning of molecular variation suggests considerable differentiation among the taxa within sections.