Genome-Wide Association Study Reveals the Genetic Variation and Candidate Gene for Grain Calcium Concentration in Bread Wheat

Abstract Calcium (Ca) plays important roles in the human body. Wheat grain provides the main diet for billions of people worldwide but is low in Ca concentrations. Here, grain Ca concentration (GCaC) of 471 wheat accessions was determined in four field environments. The wheat accessions for the Huang-Huai-Hai plain, the major wheat production region in China, contained lowest mean values for GCaC. Phenotypic data was further used for a genome-wide association study (GWAS) using a wheat 660 K single nucleotide polymorphism (SNP) array. Twelve quantitative trait locus (QTLs) for GCaC were identified on chromosomes 1A, 1D, 2A, 3B, 6A, 6D, 7A, and 7D, which was significant in at least two environments. Haplotype analysis revealed that the phenotypic difference between the haplotypes of TraesCS6D01G399100 was significant (P ≤ 0.05) across four environments, suggesting it as an important candidate gene for GCaC.