Effect of seed zinc content on grain yield and zinc concentration of wheat grown in zinc-deficient calcareous soils

Field experiments were carried out to study the effect of different seed-zinc (Zn) content on grain yield and grain Zn concentration in a bread wheat cultivar Atay 85 grown in a severely Zn-deficient soil under rainfed and irrigated conditions for two years. Three groups of seeds with Zn contents of 355, 800, and 1,465 ng Zn seed-1 were obtained through different number of foliar applications of ZnSO4.7H2O in the previous crop year. Experiments were carried out with 23 kg Zn ha-1 (as ZnSO4.7H2O) and without Zn fertilization to the soil. Grain yield from seeds with 800 and 1,465 ng Zn seed-1 content was significantly higher than that from low seed-Zn, especially under rainfed conditions. In the first year, under rainfed and Zn-deficient conditions, yield of plants grown from the highest seed-Zn content was 116% higher than the yield of plants grown from the low seed-Zn content. However, in the first year soil-Zn application combined with low-Zn seed resulted in a yield increase of 466% compared to nill Zn treatment with low-Zn seed, indicating that higher seed-Zn contents could not compensate for the effects of soil Zn application. Soil Zn application significantly increased Zn concentrations in shoot and grain. However, the effect of different seed Zn contents on Zn concentrations of plants was not significant, probably due to the dilution of Zn in tissues resulting from enhanced dry matter production. The results presented show that wheat plants grown from seed with high Zn content can achieve higher grain yields than those grown from the low-Zn seed when Zn was not applied to the soil. Therefore, sowing seeds with higher Zn contents can be considered a practical solution to alleviate Zn deficiency problem, especially under rainfed conditions in spite of it being insufficient to completely overcome the problem.