Zinc concentration (mean value)
Intact seeds of common bean accessions were manually cleaned to remove impurities, damaged grains, broken grains, and any signs of deterioration. For each accession, 25 g of seeds were washed with deionized water, followed by ultrapure 18 MΩ-cm water to remove possible contaminants from the harvest. The washed seeds were then sieved in a plastic strainer, and excess water was removed using sterile gauze. The seeds were dried at 60 °C for 3 days in a convection oven. Once dried, seeds were ground using a batch mill and then stored at 4 °C in polyethylene containers until further analysis. To determine each accession's Fe and Zn concentrations, we used an energy-dispersive X-ray fluorescence spectrometer, applying three replicates per accession. All equipment and utensils used were previously washed with a solution of nitric acid (5 %) and then rinsed with 18 MΩ-cm water.