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 relationsh ips among them. Mutations were detected in 3.2-kb and 2.1-kb amplified regions of variable cpDNA, cut with 21 and 10 restriction endonucleas es, respectively, to reveal polymorphisms. Parsimony and cluster analy ses were performed. The species pairs P. persica-P. dulcis, P. domesti ca-P. salicina, and P. cerasus-P. fruticosa were completely monophylet ic. All of the species were grouped with conventional subgenus classif ications. The subgenus Cerasus was the most diverged. Cerasus ancestor s separated from the remainder of Prunus relatively early in the devel opment of the genus. P. persica-P. dulcis, P. domestica-P. salicina an d P. armeniaca formed a second monophyletic group. Prunophora species were less diverged than Amygdalus species. The results also suggest th at the rate of mutation in Cerasus spp. chloroplast genomes is signifi cantly greater than for the other subgenera sampled.