Genetic variation among Iranian Medicago polymorpha L. populations based on SSR markers

Burr medic (Medicago polymorpha L.), a native of the Mediterranean Basin, has become a worldwide weed. Pasture cultivars have been selected, especially in Australia. The species is extremely variable, and there is little agreement on its infraspecific classification. Towards a better understanding of its variation pattern, present study examined population genetic structure and genetic diversity in Iran, employing co-dominant SSR markers. Seventy-one randomly collected plants from 14 geographical populations were sampled. Six primer pairs generated 21 polymorphic bands. The average polymorphic information content was high (0.923). Genetic diversity parameters were determined in these populations. STRUCTURE analysis and K-Means clustering identified two and three gene pools in the country. Mantel test results revealed isolation by distance among the studied populations. The cluster analysis showed correlation between genetic and geographical distance. AMOVA revealed a significant genetic difference among populations and showed that 46% of total genetic variation was due to among population diversity. These data may be useful for future breeding and conservation of this important and potentially agricultural plant.