Evaluation of genetic diversity among bread wheat varieties and landraces of Pakistan by SSR markers

Genetic diversity of 48 Pakistani wheat varieties and 12 landraces was assessed, loss of genetic diversity in bread wheat during the change from traditional landraces (LVs) to modern breeding varieties was examined, and recent trends of national wheat breeding programmes were identified. A total of 29 SSR markers, representing at least one marker from each chromosome of wheat, were used to analyze the genetic diversity. A total of 80 alleles were generated by the 29 loci with an average of 2.76 alleles per marker. A significant loss of genetic diversity was observed from LVs to elite cultivated varieties. Average genetic similarity between landraces was 61% while varieties released after 1990 showed 73% similarity. Range of genetic distance observed between all possible pairs was from 1.41 to 4.90. It was also observed that most of the varieties released from one source showed comparatively lower diversity indicating the utilization of common elite breeding material or interbreeding of released varieties.