Comparative Analysis Of Genetic Diversity Between Qinghai-Tibet Plateau Wild Barley And Chinese Landraces

The potential of SSR markers to detect the genetic relationships of barley was evaluated with 51 SSR markers distributed on seven chromosomes. The 90 barley samples originated from a wide range of regions in China, including 54 landrace accessions and 36 Qinghai-Tibet Plateau wild barley accessions. At the 51 SSR loci, 205 alleles were detected among the 90 accessions, of which 111 were common alleles. The private allele of Qinghai-Tibet wild barley (24) was about 1.3 times higher than that of the Chinese Landrace accessions (19). The number of alleles per locus ranged from 1 to 9 (Hvm20), with an average of 4.208. PIC value ranged from 0 to 0.856 among all the varieties, with an average of 0.557. The PIC value of Qinghai-Tibet Plateau wild barley varied from 0 to 0.813, with an average of 0.554, while in Chinese landraces, the markers showed a scale of 0 to 0.790. For the 49 polymorphic SSRs, the mean number of alleles per locus was 7.4. Qinghai-Tibet Plateau wild barley possessed more information than that of Chinese landraces. 24 private alleles were detected in Qinghai-Tibet wild barley, with an average of 3.429 per chromosome, while 19 private alleles were found in Chinese landraces with an average of 2.714 per chromosome. The largest number of private alleles found of Qinghai-Tibet wild barley was located on chromosome 3H, and for that of Chinese landraces, it was on chromosome 2H. The chromosome 2H of Chinese landraces was the only one showed a higher average allele per locus than that of Qinghai-Tibet Plateau wild barley, which may reflect the fact that this chromosome has been actively selected for adaptation of barley to various regions as barley chromosome 2H contains the most important genes for development and adaptation. Two dendrograms based on SSR data were constructed by using the unweighted pair-group method with arithmetic averages (UPGMA) and Neighbor-Joining analysis. Phylogenetic analysis using parsimony (PAUP) also generated a tree that was in large agreement with the two dendrograms.Our results found that: (1) The Qinghai-Tibet Plateau wild accessions showed significantly higher genetic diversity than the Chinese landrace accessions; (2) SSR markers can be used for allele identification of barley accessions; (3) The accessions could be clustered into groups according to their geographical distribution and row type; (4) at the same replicates level 2000, Neighbour-joining method generates more information than UPGMA based on our SSR markers; (5) These results suggested that Qinghai-Tibet Plateau region might be a center of genetic diversity for Chinese landraces in this study, and Qinghai-Tibet Plateau wild barley might be the ancestor of Asian barley.