Agronomic biofortification of common bean (Phaseolus vulgaris L.) cultivated in Oxisol with soil- and foliar-applied zinc

Consumption of foods with low zinc (Zn) contents has contributed to the onset of malnutrition and physiological problems in the population. Seeking to improve the nutritional quality of the grains, foliar applications of Zn have been carried out. The aim of this study was to evaluate Zn-EDTA and Zn-Amino as alternatives to ZnSO4, in foliar application, to improve the nutritional quality of the common bean cultivar 'BRSMG Madreperola'. An experiment was carried out in a greenhouse, in a factorial scheme [(3 x 5 + 1) + (1 x 3)], corresponding to three sources, five doses of foliar-applied Zn (2.5, 5.0, 10.0, 15.0 and 20.0 mg dm(-3)), one control, without Zn application and three doses of KCl (0.0, 0.2 and 0.4%) along with the 5 mg dm(-3) dose of Zn, through foliar application of ZnSO4, in a randomized block design with four replicates. The foliar application of Zn-EDTA was found to be more effective than other sources in increasing the levels and quantities of zinc and other nutrients in common bean grains. Furthermore, increasing doses of Zn-EDTA resulted in lower phytotoxic effects in common beans when compared to doses of ZnSO4 and Zn-Amino, with only a minimal reduction in grain yield at the dosage that promoted higher zinc contents in the grains. The foliar application of different doses and sources of zinc leads to increased zinc contents in grains, which could help improve their quality and nutritional value for human consumption, reducing zinc malnutrition.