Population genetic structure based on SSR markers in alfalfa (Medicago sativa L.) from various regions contiguous to the centres of origin of the species

Abstract

differentiated using mosphological descriptors, and although such descriptions are indeed useful from a breeding perspective, they are inadequate for analysis of population genetic structure. Because alfalfa is native to northwestern Iran, a high level of genetic diversity may be expected among individual plants within and between populations. Thus, the objectives of the present study were to (a) identify polymorphic SSR markers with high informative value for the Iranian alfalfa in terms of population differentiation and identification, (b) estimate the genetic population structure, and (c) compare the genetic diversity between different geographical regions, especially across different latitudes. The average within-population genetic diversity evaluated using eight simple sequence repeat (SSR) markers ranged from 0.82 in the Kerman population (low latitudes) to 0.93 in the Ghareyonjeh population (higher latitudes). The genetic relationships among populations were analysed using cluster analysis by UPGMA algorithm based on the coancestry coefficient matrix. The higher distance between Ghareyonjeh population and others was due to the presence of a specific allele in all plants within this population. The trend of changes in genetic diversity across populations was concordant with latitude changes. The obtained results suggest that SSR markers are useful for identification of alfalfa populations, for assessing interpopulation and intrapopulation genetic diversity, and for estimation of genetic differentiation.