Unravelling the Genetics Basis of Copper Tolerance and the Effects of Elevated Soil Copper on Wheat Yield Components

ABSTRACT Copper (Cu) contamination of agricultural soils poses a serious risk to wheat productivity and grain quality. This study evaluated the effects of elevated soil Cu on yield‐related traits in wheat and dissected the genetic basis of Cu tolerance using a diverse panel of 195 spring wheat genotypes grown under Cu‐contaminated and non‐contaminated soils. Contaminated soils exhibited higher Cu concentrations than controls (158.53 vs. 18.07 mg kg −1 ), whereas soil pH and major nutrients showed only minor differences between treatments. Highly significant treatment and genotypic effects were detected for most spike and yield traits, with high broad‐sense heritability (H 2 = 0.75–0.96) and no significant genotype × treatment interactions. Grain Cu concentration varied widely among genotypes (0.096–207.75 mg kg −1 ), with the majority exceeding acceptable limits. Cu concentration was not correlated with yield traits or their reductions under Cu stress. Copper stress increased heading date, spike length, spike density, and grain number per spike but reduced spike weight and kernel size traits. Genome‐wide association studies identified 61 significant SNPs for Cu concentration and numerous loci for yield and kernel traits, distributed across most wheat chromosomes. Candidate gene analysis revealed 41 genes associated with Cu content and 209 genes linked to yield traits, including loci with moderate phenotypic effects. Two SNPs were jointly associated with reduced Cu accumulation and favourable yield traits. One genotype (Maris Ensign) combined low grain Cu with competitive yield. However, 19 other genotypes were selected for high‐yielding and intermediate levels of Cu, highlighting their potential for cultivation and breeding in Cu‐contaminated environments.