Soil and foliar application of selenium in rice biofortification

• Selenium and main nutrients content in rice (Oryza sativa) in Brazil was studied.
• Foliar and soil application of Se increased Se concentrations in rice grains.
• Soil application was more effective.
• Selenate in the soil increased shoot dry matter production.
• Foliar application of selenate and selenite increased grain yield.

Selenium (Se) is essential for humans and animals because of its antioxidant properties, which form part of a series of chemical reactions. The aim of this study was to evaluate the effect of different Se application forms and sources on rice growth, grain yield, and rice Se concentration and accumulation, as well the content of N, P, Mg, S, B, Cu, Fe, Mn, and Zn in rice grains. The experiment was carried out in a greenhouse with 4-dm3 pots containing a sandy clay loam Red-Yellow Latosol. The experimental design was a completely randomized 2 × 2 × 2 factorial scheme (two Se doses × two forms of Se application, soil or foliar × two Se sources, selenate or selenite), with five replicates. Selenium in rice plants was analyzed by total reflection X-ray fluorescence spectrometry (TXRF). The results shows that soil selenate application was more effective for shoot dry matter production and grain Se accumulation than selenite. Foliar application of both selenate and selenite increased grain yield. This study provides useful information concerning agronomic biofortification of rice, showing that both soil and foliar Se application could be used for increasing Se content in edible parts, which could result in health benefits.