Estratégias de adubação visando à biofortificação com zinco em grãos de feijão da cultivar carioca BRS MG Uai

Zinc is a nutrient that needs to be present in adequate amounts in the population's diet, but this is not always the case due to difficult access to foods that provide it. The enrichment of bean grains with zinc through agronomic biofortification can be an interesting strategy, since beans are a staple food present in the diet of a significant portion of the Brazilian population. The objective of this work was to evaluate the agronomic behavior of the carioca bean cultivar BRS MG Uai, as well as the zinc enrichment effect of its grains, when subjected to different zinc fertilization strategies. To this end, an experiment was installed on 03/01/2021 at the CDTT /DAG – UFLA, in Ijaci MG, in a 3x4 factorial scheme, three base fertilizers (350 kg.ha-1 (NPK) 04-28-08, 350 kg.ha-1 of (NPK) 04-28-08 with 10% zinc in the granule, 350 kg.ha-1 of (NPK) 04-28-08 associated with 50 kg.ha-1 of zinc sulfate heptahydrate ) and four foliar fertilization strategies (non-application, application of 5 kg.ha-1 of zinc sulfate heptahydrate, 6.67 kg.ha-1 of EDTA zinc chelate and 2.5 L.ha-1 of zinc oxide zinc). The foliar fertilizations were divided into two equal doses (half in each application), at stages R5 (pre- flowering - 04/03/2021) and R8 (pod filling - 04/26/2021). The design was in randomized blocks with 4 replications, the plots were formed by four lines of 4 meters in length, spaced 0.5 meters apart, the two central lines being harvested as a useful plot. At harvest (05/28/2021), 10 plants were collected at random, with which the yield components, number of pods per plant, number of grains per pod and mass of one hundred seeds were determined. The harvested grains had their moisture determined for later correction, a 100-gram sample was separated and subjected to sieves, evaluating the retention in sieves 12, 11 and bottom residue for the grains, the grain yield was determined after being adjusted to 13% moisture. For the evaluation of zinc in the grains, they were duly ground and sent to the laboratory, which, using the Nitro Perchloric digestion methodology and determination by ICP-OES, determined the zinc levels. The data obtained were submitted to analysis of variance and the effect of the treatments was verified by the F test at 5% of significance. The results obtained showed that there were no statistical differences for the component analyzes of yield and sieve retention, which is probably associated with the fact that the cultivation took place in a period of severe water deficit, with total rainfall in the cultivation cycle of 105.1 mm, being 95.4 only in the month of March. However, for the zinc content in the grains, it was possible to verify that the different sources of foliar fertilizer allowed a significant increase, in which all were superior to the control.