Copper is an essential trace element in humans, and copper deficiency can compromise health. Wheat is a major staple crop worldwide, and biofortification of wheat grain with copper is a cost-effective strategy to help alleviate dietary copper deficiency. However, the genetic basis of grain copper content in wheat remains poorly understood. Here grain copper content was evaluated in 349 wheat accessions, and a genome-wide association study (GWAS) was performed using the Wheat 660K SNP array. In total, 775 significant SNPs were identified, mainly on chromosomes 1B, 4A, and 7A; among these, 56 SNPs were consistently detected in four or more replicates. Haplotype analysis indicated that GCuCHap₁B and GCuCHap₄A are key loci associated with grain copper content and show a significant pyramiding effect. Based on bioinformatics and haplotype analysis, TraesCS1B03G1265400 and TraesCS4A03G0093900 were proposed as candidate genes for regulating grain copper content. These results clarify the genetic architecture of grain copper content in wheat and provide a valuable foundation for developing germplasm with elevated grain copper content for wheat quality improvement breeding.
Xi et al. (Fri,) studied this question.