Selenium biofortification via soil and its effect on plant metabolism and mineral content of sorghum plants

Sorghum has excellent potential to be used in the supplementation of selenium (Se) to humans and animals when compared with other grain crops due to its protein content, rusticity, and great tolerance to various stressing conditions. Few studies have been dedicated to explore Se biofortification strategies in sorghum plants, especially in tropical agroecosystems. In this context, the objective of this work was to evaluate the efficiency of different Se doses (0, 60, 240, and 480 µg dm−3) and Se sources (SeA - potassium hydroxy-selenide, SeB - methyl hydroxy-selenide, SeC - hydroxy-selenide, and SeD - sodium selenate) in Se biofortification of Sorghum bicolor L., as well as in its antioxidant system, and the contents of carbohydrates and mineral in response to soil Se application. The increase in Se content in the grains and the shoots were closely related to the increments in applied Se doses. The greater absorption efficiency by the roots and % Se recovery occurred with the application of SeD. Selenium application influenced both the antioxidant system and carbohydrates in a positive way. In summary, considering the parameters evaluated, the Se sources SeB (methyl hydroxy-selenide) and SeC (hydroxy-selenide) at a dose of 240 µg dm−3 of Se and SeD (sodium selenate) at a dose of 60 µg dm−3 of Se are considered promising for the biofortification of sorghum.