Zinc application improves the yield and nutritional quality of three green bean genotypes grown in a Red Latosol

Abstract

Zinc (Zn) deficiency affects a large part of the world’s population. Agronomic biofortification is an important tool used to address this situation. This work aimed to: (i) evaluate the effect of Zn application on soil Zn availability using Mehlich-1 and DTPA extractants; (ii) evaluate the effect of Zn fertilization on green bean growth; and (iii) correlate Zn availability with the nutritional quality and agronomic biofortification of pods. Three green bean genotypes were grown in Red Latosol using two Zn fertilizers (ZnO and ZnSO4) at five rates (0, 5, 10, 20, and 30 mg Zn kg−1), with three replicates. Zinc application significantly increased soil Zn availability, regardless of the fertilizer used. On average, 22.8 % more Zn was extracted with Mehlich-1 than with the DTPA method. High genotypic variation in shoot, pod, and root dry weight production was observed for the different treatments. Compared to the control, the application of ZnSO4 in Manteiga and Torino genotypes increased the pod dry weight by 41.4 % and 91.0 % at 14.0 and 14.6 mg Zn kg−1, respectively, while in the Favorito genotype there was no significant increase. The highest Zn concentrations in bean pods of Favorito and Torino genotypes were obtained at 17.5 and 19.9 mg Zn kg−1 as ZnSO4, respectively. Although there was high variability of responses to the Zn treatments, the application of Zn-containing fertilizers in Zn-deficient soil increased both pod production and the agronomic biofortification of pods.