Chen, S., Zhang, X., Ma, X. and Huang, L. 2013. Assessment of genetic diversity and differentiation ofElymus nutansindigenous to Qinghai-Tibet Plateau using simple sequence repeats markers. Can. J. Plant Sci. 93: 1089-1096. Elymus nutans Griseb., an important alpine forage grass, is widely distributed in the Qinghai-Tibet Plateau. A total of 50 E. nutans accessions from the eastern Qinghai-Tibet Plateau were analyzed using simple sequence repeats (SSR) markers from wheat and Elymus species. Our results show that a total of 144 reliable bands were generated, of which 132 (91.38%) were found to be polymorphic. Nei-Li's genetic similarity coefficients ranged from 0.515 to 0.870 with an average of 0.719, which shows a high level of genetic diversity and a broad genetic base among accessions. There was a low correlation between genetic distance and geographical distance (r=0.121, P=0.088) in the region, which is consistent with the unweighted pair group method with arithmetic average cluster analysis of accessions. The mountain ridges and river valleys in the eastern Qinghai-Tibet region could serve as genetic barriers for pollinator movement and seed dispersal. The rule of the most genetic diversity at medium altitude of E. nutans in the Qinghai-Tibet Plateau was also validated in the study. The implications of these results for the conservation of E. nutans are discussed.