Seed priming and soil application of zinc decrease grain cadmium accumulation in standard and zinc-biofortified wheat cultivars

ABSTRACT Context. Cadmium (Cd) is a toxic metal for both plants and humans. Wheat grown on Cd-contaminated soils may accumulate toxic levels of Cd in grains. Aim. This study aimed to compare soil zinc (Zn) application and seed Zn-priming for decreasing grain Cd concentration in standard and Zn-biofortified wheat cultivars grown on Cd-spiked soil. Methods. Standard (Jauhar-2016) and Zn-biofortified (Zincol-2016) wheat cultivars were grown in pots filled with Cd-spiked soil (8 mg Cd kg−1). The tested Zn treatments were un-primed, hydro-primed, and Zn-primed seeds with and without soil Zn application at 8 mg kg−1. Key results. Zinc treatments significantly mitigated the toxic effects of Cd on the growth and physiological parameters of both cultivars. As compared to control, all Zn treatments significantly increased Zn and decreased Cd concentration in grains of the cultivars. On average, the maximum increase in grain Zn concentration over control was approximately 36% with Zn-priming + soil Zn. The same treatment, as compared to control, decreased grain Cd concentration by 42% in Zincol-2016 and 35% in Jauhar-2016. Grain Cd concentration was within the permissible level (≤0.2 mg kg−1) in Jauhar-2016 at all Zn treatments and in Zincol-2016 at Zn-priming + soil Zn. Conclusion. Soil Zn application, seed Zn-priming, and their combination were effective in decreasing grain Cd accumulation in wheat grown on Cd-contaminated soil. Implication. Zinc treatments, especially the combination of soil Zn application and seed Zn-priming, should be recommended for wheat grown on Cd-contaminated soil.