Evaluation of the genetic structure present in natural populations of four subspecies of black cherry (Prunus serotina Ehrh.) from North America using SSR markers

Black cherry (Prunus serotina) is a fruit tree native to North America, and almost all parts of this plant have some use. This species is a complex of five subspecies with morphological differences and distinctive habitats. The genetic structure of 18 natural populations of black cherry was evaluated with 16 microsatellite markers. One hundred sixty-four individuals were collected across seven states of Mexico, and another 14 in Texas. These individuals represented subspecies capuli (38), eximia (14), serotina (53), and virens (73). A total of 246 alleles was detected for the 16 markers. A Neighbor-Joining tree and a principal coordinate analysis (PCoA) revealed two major groups of individuals while Bayesian clustering analysis detected six main clusters that do not clearly correspond to the four putative subspecies studied. At the p ≥ 0.900 cut off values, the composition of these clusters indicates geographical structuring of the samples; their genetic differentiation suggests gene flow among populations with geographical proximity. This is the first time that molecular markers have been used to assess the genetic structure present in natural populations of four subspecies of black cherry with the goal of evaluating their taxonomic classification and providing guidelines for in situ conservation of genetic resources of the species.