Identification of genes associated with zinc and copper concentrations in walnut (Juglans regia L.) by GWAS analysis

154 walnut genotypes from various geographic regions were analyzed in the study. Micronutrient concentrations of zinc (Zn) ranged from 1.61 to 8.98 mg/100 g, and the concentrations of copper (Cu) varied between 0.12 and 0.38 mg/100 g. 16,473 SNPs were generated using Diversity Array Technology (DArT) for genome-wide association (GWAS) studies. The Mixed Linear Model (MLM) utilizing the Q + K model revealed seven associated markers for the element Zn in 2021 and four in 2022. The MLM (Q + K) model indicated two associated markers for the element Cu in 2021 and three in 2022. The markers found in this study were significantly associated with the levels of Zn and Cu in different walnut genotypes. One potential candidate gene for Zn was identified based on sequences showing homology to linked SNP. The markers associated with Zn and Cu can be effectively used in walnut plant breeding programs to assist in selecting Zn and Cu traits.