PHYLOGENETIC-RELATIONSHIPS OF CULTIVATED PRUNUS SPECIES FROM AN ANALYSIS OF CHLOROPLAST DNA VARIATION

Chloroplast DNA (cpDNA) restriction-site mutations in seven cultivated Prunus species were compared to establish the phylogenetic relationships among them. Mutations were detected in 3.2-kb and 2.1-kb amplified regions of variable cpDNA, cut with 21 and 10 restriction endonucleases, respectively, to reveal polymorphisms. Parsimony and cluster analyses were performed. The species pairs P. persica-P. dulcis, P. domestica-P. salicina, and P. cerasus-P. fruticosa were completely monophyletic. All of the species were grouped with conventional subgenus classifications. The subgenus Cerasus was the most diverged. Cerasus ancestors separated from the remainder of Prunus relatively early in the development of the genus. P. persica-P. dulcis, P. domestica-P. salicina and P. armeniaca formed a second monophyletic group. Prunophora species were less diverged than Amygdalus species. The results also suggest that the rate of mutation in Cerasus spp. chloroplast genomes is significantly greater than for the other subgenera sampled.