1 research outputs found
Genome-Wide Association Mapping for Drought Tolerance Traits at Seedling Stage Using Nebraska Winter Wheat
Wheat (Triticum aestivum L.) is the first important and strategic cereal crop around the world. Wheat crop has been widely cultivated in very diverse environments, this means it is exposed to different biotic and abiotic stresses. Drought tolerance becoming one of the most challenge in the wheat breeding program. The most critical problem in wheat production is the shortage of water at the seedling stage, mid-season water stress, terminal stress or a combination of any two or three stages. So, the detection of genotypes variation in drought tolerance at seedling stage could help in selection intensity in the wheat breeding program for drought tolerance. In this study 157 genotypes of winter wheat in addition three checks variety (Anton, Harry as drought tolerant checks and Wesley drought susceptible check) were grown in uncontrolled greenhouse. Three drought traits were taken (days to wilting DW, leaf wilting degree LWD and stay green SG) all of these traits were visual scored and ranged from (1 no wilted or yellow color to 9 full wilted or green plants). LWD was scored 4 times each two days and all scored was summed to only one trait sum of wilting degree SWD. Highly genetic variation was found in all observed traits and the genetic heritability was found 91.44, 91.32 and 86.86 for all traits, respectively. Highly significant correlation was observed between all traits under investigation. Genome wide association study GWAS was performed using 9,765 single nucleotide polymorphism SNPs marker using mixed liner model with 20% false discovery rate and identified ten SNPs associated with two drought traits i.e., days to wilting (DTW) and sum of wilting degree (SWD). In total, ten marker-trait associations MTAs were detected. Two SNPs in the 6B chromosome were associated with SWD. Also, eight SNPs were associated with DTW three in chromosome 6B and four in 2D and one in chromosome 5B. Key words: GWAS, Drought tolerance, Winter Wheat, Seedling stage<br