Effect of zinc and iron foliar sprays on biofortification and yield of wheat grain

Abstract:

Micronutrient deficiency among wheat-dependent populations has been trending upward across South Asia for two decades, yet agronomic biofortification through foliar sprays offers a cheap, immediate fix that doesn't require breeding new varieties. This research evaluated the effect of zinc sulphate (0.25%, 0.50%) and ferrous sulphate (0.25%, 0.50%) foliar applications, alone and in combination, on grain micronutrient concentration, yield, and quality of wheat variety BARI Gom 33 during Rabi 2022-2023 at Barisal Agricultural College, Bangladesh. The combined spray of ZnSO₄ 0.50% + FeSO₄ 0.50% at booting and grain-filling stages raised grain zinc from 24.3 to 42.4 mg/kg (+74.5%) and grain iron from 32.1 to 49.3 mg/kg (+53.6%) without affecting yield (4.51 vs. 4.43 t/ha for control). Zinc and iron concentrations correlated positively (r = 0.88), suggesting synergistic uptake. These results demonstrate that two foliar sprays costing under USD 15/ha can meaningfully biofortify wheat grain for zinc- and iron-deficient Bangladeshi populations.