Use of selenium-enriched urea in biofortification of dry beans

Abstract

Dry beans (Phaseolus vulgaris L.) is a crop of global importance, serving as a food source for millions of people. Improving its capacity to effectively nourish populations is therefore an urgent need for research with this important staple food crop. One of the strategies in this regard is genetic biofortification, which allows the selection of most appropriate genotypes for providing nutrients to humans efficiently. Selenium (Se) is one of such nutrients and is very relevant because of its several benefits for human health. This work aimed to select dry beans genotypes that are more efficient in accumulating Se, through the application of Se-enriched urea under different experimental conditions. The experimental areas are located in four municipalities in the State of Minas Gerais, Brazil: Patos de Minas, Lambari, Lavras, and Uberaba. The experiment followed a completely randomized design in a split-plot system, with 12 dry beans genotypes, 2 Se application treatments (normal prilled urea - control - and Seenriched urea), and 4 replicates, totaling 96 subplots. The Se source used to enrich urea was sodium selenate with 98% purity, which was mixed with the nitrogen fertilizer at the concentration of 480 mg kg -1 of Se, resulting in the dose of 48 g ha -1 of Se, applied as topdressing fertilization (100 kg ha -1 of urea). Selenium-enriched urea improved grain yields under water stress conditions in Lavras in most genotypes, as well as the protein content in grains of selected genotypes, in Uberaba. Synergistic and antagonistic interactions occurred in the absorption of selenium and phosphorus, and selenium and sulfur in the genotypes, depending on grain yield and soil characteristics of each experimental area, with emphasis on pH and clay content. Selenium-enriched urea was efficient in increasing the selenium contents in the grains in all genotypes evaluated. However, the most recommended for biofortification were the earlycycle genotypes, especially BRS 9435 Cometa, followed by BRSMG Madrepérola and BRSMG Realce.