Genetic diversity and spatial genetic structure of Caucasian apple (Malus orientalis Uglitzk.) populations based on microsatellite markers for conservation strategy

In Eurasia, M. orientalis Uglitzk. (Caucases apple) is a tree with important ecological and economic (fruit) benefits. We measured eight quantitative morphological traits, none of which showed significant differences among the investigated Caucasian apple populations. In this research, we used 26 microsatellite (SSR) markers to investigate genetic diversity and define unit conservation in the Caucases apple. The mean values of genetic diversity,allelic richness (Ar), private allele (Ap), expected heterozygosity (H _E ) and observed heterozygosity (H _O ) were 1.74, 0.21, 0.65 and 0.76, respectively. In the regions studied, three major genetic clusters and two significant genetic barriers were discovered. Our gene flow findings revealed that there is little connection between M. orientalis population in the Caucasus indicating habitat fragmentation. Two regions in the Hyrcanian forest and one in the Zagros forest were identified as having the highest priority for conserving the genetic diversity of the Caucases apple.