Wheat grain size and morphology are the main factors determining yield, and exploring the genetic loci associated with grain-related traits and screening related candidate genes will lay an important foundation for improving wheat yield. In this study, 337 wheat varieties were used as materials to perform genome-wide association studies (GWAS) of four grain traits of wheat, using a Q+K mixed linear model (MLM) in three different environments (E1: Yangling, Shaanxi Province, 2020; E2: Doukou, Shaanxi in 2020; E3: Yangling, Shaanxi Province in 2021), including 1 000-grain weight, grain length, grain width, and grain length to width ratio. In the three environments, the four grain traits of different wheat varieties showed extensive phenotypic differences, with coefficients of variation ranging from 5.31% to 14.76%. Among them, the variation range of grain length was the smallest, and the variation range of 1000-grain weight was the largest. The GWAS results showed that 49 significant SNP loci were detected in at least 2 environments, distributed on chromosomes except for 1B, 4A and 7D, explaining phenotypic variations ranging from 3.36% to 12.73%. Thirty-one pleiotropism loci were detected, three of which on chromosome 5A stably associated with three grain traits (1000-grain weight, grain length, and grain width) in the three environments, with phenotypic contributions ranging from 3.51% to 7.74%.Candidate genes were explored within a physical interval of 200 kb upstream and downstream of the stably associated SNP loci, and five genes(TraesCS2B01G225400, TraesCS4D01G016900, TraesCS5A01G454100, TraesCS5B01G459-500, and TraesCS6B01G064000) were screened as potentially related to wheat grain traits on chromosomes 2B, 4D, 5A, 5B, and 6B. |