Rice (Oryza sativa L.) Biofortification with Selenium: Enrichment Index and Interactions among Nutrients

Selenium is an antioxidant trace mineral important for human health and development. Therefore, the growing demand for efficient, bioeconomic and sustainable strategies to increase Se content in cereals, namely, rice, is justified. In this context, biofortification is a strategy that can promote nutrient enhancement in food crops and, therefore, increased nutrient uptake in the human body. In this framework, a technical itinerary was implemented using a rice genotype (OP1509), through foliar spraying with two selenium concentrations (25 and 100 g Se.ha−1) of sodium selenate (Na2SeO4) and sodium selenite (Na2SeO3). It was found that the average Se biofortification index was 1.8–4.7- and 5.4–6.0-fold in selenate and selenite treatments, respectively. The contents of Se, Ca, Fe, K, P, C, H and O in brown rice grains were also quantified and it was found that both forms of fertilizers increased Zn contents with 25 g Se.ha−1, but decreased with 100 g Se.ha−1. Moreover, Ca only increased significantly with selenate pulverization. The application of both forms also increased grain weight, but did not affect the colorimetric analysis. It is concluded that the applied itinerary can be implemented to minimize Se malnutrition.