MAGNÉSIO NO METABOLISMO SECUNDÁRIO E NA QUALIDADE BIOQUÍMICA DE GRÃOS DE SORGO

Abstract

Sorghum (Sorghum bicolor L.) has great agricultural importance due to its adaptability to adverse environmental conditions and the nutritional and functional potential of its grains. In this context, nutritional management may influence both productivity and the synthesis of secondary metabolites such as flavonoids and tannins. The objective of this study was to evaluate the effect of different magnesium doses on isoflavone, tannin, magnesium contents, and grain yield of second-crop sorghum. The experiment was conducted at the experimental area of the Federal University of Mato Grosso do Sul using a randomized block design with five magnesium doses: 0, 445, 890, 1335, and 1780 g ha⁻¹. Catechin, daidzin, genistein, genistin, quercetin, ellagic acid, procyanidin B2, grain magnesium content, and grain yield were evaluated. Statistical analyses included analysis of variance, regression analysis, canonical variables, and Pearson correlation. Magnesium doses significantly influenced catechin and ellagic acid contents, showing a quadratic response. No significant effects were observed for grain yield or magnesium content in grains. Multivariate analyses demonstrated associations between phenolic compounds and changes in secondary metabolism in response to magnesium supplementation. Magnesium doses close to 600 to 700 g ha⁻¹ promoted the most favorable responses for the evaluated bioactive compounds, indicating potential for improving the functional quality of sorghum grains.