Microsatellite-based assessment of genetic diversity in stripe rust resistant NUWYT candidate lines

Abstract

Stripe rust is one of the most devastating diseases, caused by Puccinia striiformis f. sp. tritici, affecting a huge amount of wheat crops worldwide. In this study, the genetic diversity of 16 National Uniform Wheat Yield Trial (NUWYT) candidate lines was evaluated by using 22 screened microsatellite markers. These lines were found resistant for stripe rust at adult plant stage. These wheat microsatellite markers identified a total of 38 alleles, with an average of 2.3 alleles per microsatellite locus. The number of alleles ranged from one to five alleles and the highest number of alleles were associated with B genome (25), as compared to D (11) and A (2) genomes. The allelic polymorphism index content (PIC) reflecting the gene diversity of these microsatellite markers ranged from 0.00 to 0.66, with an average of 0.27. The maximum PIC value of 0.66 was observed for xgwm 159-5B and 0.64 for xgwm 413-1B. The gene diversity ranged from 0.00 to 0.71, with an average of 0.30. The genetic similarity matrix was used to construct a dendrogram and the cluster analysis was performed by the use of unweighted pair-group method with arithmetic average algorithm. This divided the entire 16 candidate lines into three main clusters on the basis of their similarity. Our results indicate that the genetic diversity among the 16 candidate NUWYT lines was very narrow.

Keywords:

• genetic diversity
• SSR analysis
• stripe rust resistance

Acknowledgements

The authors are extremely thankful to the Higher Education Commission, Pakistan (HEC) (Project No. IPFP/HEC/2011/0213) for funding the study. The authors are also obliged to Dr Abdul Mujeeb Kazi, Project Director of Wheat wide crosses and Cytogenetics, NARC Islamabad, for his technical assistance.