Analysis of Genetic Diversity and Tapping Elite Alleles for Plant Height in Drought-Tolerant Wheat Varieties

Abstract

To make advances in wheat breeding,it is important to study germplasm diversity of winter wheat accessions,and identify SSR markers associated with important agronomy traits,for example plant height.Plant height reduction has observably contributed to the lodging resistance and yield increase of wheat in the last decades.In this study,we selected 136 historical winter wheat accessions planted in northern China and 117 SSR markers evenly distributing on the chromosomes of wheat to reveal the genetic diversity.A total of 1484 alleles of loci were detected from the accessions.The average alleles per locus were 12.6 which varied from 2 to 42.The polymorphism information content(PIC) value ranged from 0.016 to 0.941,with an average of 0.640.Most of the similar varieties were cultivated by the same breeders or belonged to the similar ecotype.Some of them were in accordance with the pedigree information.The most varieties cultivated in different ages were also clustered together.A total of 19 significant markers associated with plant height were identified(P0.01) under drought stress.Among them,Xbarc168(2D),Xgwm285(3B),Xgwm126(5A),Xgwm95(2A),Xgwm212(5D),and Xwmc396(7B) were significantly associated with plant height(P0.001).In well-watered environment,a total of 19 significant marker-trait associations were also identified(P0.01),of which Xgwm285(3B),Xgwm95(2A),Xbarc125(7D),Xgwm212(5D),Xwmc396(7B),Xgwm130(2B),and Xgwm495(4B) were strongly associated with plant height(P0.001).220,181,167,and 99 bp were the elite alleles of Xgwm285,Xgwm495,Xbarc125,and Xgwm212 for reducing plant height,respectively.With the rapid development of molecular biology and genomics,it is expected to utilize association analysis more widely in genetic research,germplasm enhancement and breeding in wheat.