Genetic evaluation of Populus caspica Bornm. and establishment a collection for its protection in Iran

The destruction of Hyrcanian forests has led to the fragmentation of the Caspian poplar (Populus caspica Bornm.) habitat and the destruction of a large part of its genetic resources. This species is distributed in the southern regions of the Caspian Sea, although it has been reported in the list of endangered trees. To select various trees and conserve their gene pools via the collection, their diverse habitats throughout the southern Caspian strip from Astara to Golestan forest were studied, and subsequently, 20 habitats were identified. DNA extraction from the leaves of 359 trees belonging to these habitats was then extracted. After homogeneity removal, genetic parameters were estimated for 314 trees using 14 microsatellite markers. These primers showed 80 alleles in 314 trees of P. caspica. Expected heterozygosity values in each locus ranged from 0.085 to 0.765, while the observed heterozygosity ranged from 0.069 to 0.689. The highest and lowest amount of allelic richness with values of 3.03 and 2.17 were estimated in Loveh and Tonekabon, respectively. The inbreeding coefficient was a possible factor in the Hardy-Weinberg equilibrium deviation. Only 0.8% of trees in a population were immigrants. In general, gene flow was asymmetric and its severity was low. Mantel test showed that there was no significant correlation between genetic distance and geographical distance. However, altitude was a serious barrier to gene flow across the eastern and western slopes of the Caspian poplar distribution. Finally, to preserve its genetic resources, based on the results of molecular, some stocks of this species were clonaly propagated and planted in a relevant collection.