Assessing genetic diversity for drought and heat stress tolerance of Nepalese wheat genotypes by SSR markers.

The productivity of wheat in Nepal is low compared to the world average and very low compared to countries like New Zealand and Ireland, and it has remained nearly stagnant in the past ten years. Genetic factors, water and climate seem to be a limiting factor for wheat productivity in Nepal. Breeding for tolerance to biotic and abiotic stress and study of their genetic stability under stress are important for improving the productivity of wheat. We assessed the genetic diversity of 20 genotypes of wheat released or in the pipeline in Nepal, by 12 SSR markers linked to drought tolerance and 4 SSR markers linked to heat stress tolerance. The first set clustered 20 genotypes into 4 clusters, 3 of which further sub clustered into 8 sub clusters. 2 of the genotypes, namely BL-4707 and NL-1325, are distantly related to the rest of the genotypes. The second set of SSR markers clustered 20 genotypes into 5 clusters, 2 of which further subclustered into 4 subclusters. 2 of the genotypes, namely NL-1247 and NL-1325, are distantly related to each other and the rest of the genotypes. This study identified both closely related genotypes and distantly related genotypes of wheat in alleles presumably linked to drought and heat stress tolerance. The finding of this study is expected to be useful for breeding for drought and heat stress tolerance and study of the interaction of genotypes and environment as well. [ABSTRACT FROM AUTHOR]