Agronomic biofortification of common bean grain with zinc

Abstract: The objective of this work was to evaluate the effects of the split and combinated application of foliar zinc (ZnF) + soil Zn (ZnS) on Zn concentration in the grains (ZnCG) of common bean (Phaseolus vulgaris). Two experiments were carried out in a greenhouse during two seasons. In the first experiment, two common bean cultivars received six ZnF rates (0, 120, 240, 480, 720, or 1,200 g ha-1), with split applications at the R5, R7, and R8, or R7 and R8, or R8 plant stages. In the second experiment, one cultivar received three ZnS rates (0, 5, or 10 kg ha-1) combined with ZnF rates (0, 1, 1.5, 3, 6, or 10 kg ha-1). In the first experiment, with the ZnF increment, ZnCG increased linearly from 15.3 to 20.7 mg kg-1. ZnF splitting did not affect ZnCG. In the second experiment, ZnF without ZnS did not affect ZnCG. ZnS doubled ZnCG in comparison with the treatment without ZnS application. At 5 kg ha-1 ZnS, the highest ZnCG (67.5 mg kg-1) was obtained with 7.8 kg ha-1 ZnF. At 10 kg ha-1, the highest ZnCG (66 mg kg-1) was obtained with 4.9 kg ha-1 ZnF. ZnF splitting is not advantageous over a single application, and the combination of ZnF and ZnS increases ZnCG in common bean, in greenhouse conditions.