Genetic structure of three wild almond populations (Prunus scoparia)

Iran ranks the third one in the world for the production of almond and over 30 Amygdalus (Prunus) species, subspecies or ecotypes have been identified in the country. Among the wild almond species, P. scoparia is used as the rootstock for almond in southwest of Iran. This species provides a gene pool of valuable characteristics for breeding and improvement of the cultivated almond. The present study considers genetic diversity analysis of three P. scoparia populations by using ISSR markers. We tried to show genetic divergence versus admixture of these populations. ISSR loci showed 50% polymorphism among 38 wild almond trees studied. The highest values for the genetic diversity, shannon index and percentage of polymorphism were observed in Deihook (Yazd) population. In cluster analysis, Deihook population stands much separated from the other two populations while, Rashm-Moalem (Semnan) and Fasa (Fars) populations showed higher genetic exchange among their trees. AMOVA test showed great genetic difference among the studied populations. The Mantel test did not show association between the genetic and geographical distances of the studied populations. This is possibly due to gene exchange among these populations which was also shown by reticulation and STRUCTURE analyses.