Comparative Evaluation of Foliar-Applied Selenium Biofortification in Different Rice Genotypes

Selenium (Se) biofortification in rice presents a promising strategy to address Se deficiency in populations relying on rice as a staple food. This study evaluated the impact of foliar Se application on Se accumulation, its distribution in unpolished and polished rice grains, grain yield, and antioxidant capacity across 21 rice genotypes. Foliar Se application significantly improved grain yield, with increases ranging from 5.7 to 67.5% compared to non-foliar Se application. Se concentrations in both unpolished and polished grains were notably enhanced by foliar application, reaching 41.1–543.9 µg kg−1, whereas non-foliar treatments resulted in much lower concentrations (0–30.5 µg kg−1). Foliar Se also altered Se partitioning, decreasing Se retention in unpolished grains (from 9.8–100% under non-foliar application to 19.7–66.1% with foliar Se application) and increasing its proportion in polished rice. Se loss during polishing was genotype-dependent and generally reduced by foliar Se application (9.4–72.3%). Antioxidant capacity was highest in unpolished rice and varied among genotypes, increasing further with foliar Se. A positive correlation between grain antioxidant capacity and Se concentration was observed in unpolished, but not polished rice. Overall, these findings demonstrate the effectiveness of foliar Se biofortification in enhancing Se content and antioxidant properties, emphasizing the importance of genotype selection such as RD16, RD79, KDML105, K2, KJ CMU 107, and HMD to maximize biofortification benefits.