Selenium biofortification of rice grains and implications on macronutrients quality

Selenium is an essential element for human health but its intake is low. Accordingly, biofortified rice with this trace element can be prophylactic to consumers. In this context, this study aimed to develop an agronomic itinerary for rice biofortification with selenium, considering sodium selenite and selenate as foliar fertilizers. Since both forms of selenium fertilizers have different metabolic specificity among genotypes, the implications on sugars, fatty acids and proteins quality were also assessed. Biofortification was performed in field trials, in four target genotypes, applying both foliar fertilizers with concentrations ranging between 0 and 300 g Se ha⁻¹. It was found that biofortification with sodium selenite caused, relatively to sodium selenate, a higher accumulation of selenium in the grain. Application of high concentrations of sodium selenite and selenate increased total lipids in all the genotypes, mostly oleic acid (C18:1), linoleic (C18:2) and palmitic acid (C16:0). Sugars (with the concentration pattern being sucrose > glucose > raffinose > fructose) and proteins showed a similar trend. It is concluded that biofortification of crops with selenium is more effective with 120–300 g Se ha⁻¹, but macronutrients quality in the flour varies significantly within rice genotypes.