Selenium Biofortification of Grain Maize Through Foliar Application of Sodium Selenate: Selenium Accumulation and Recovery by the Grain

The study was conducted to investigate the effects of sodium selenate foliar application on the biofortification of selenium (Se) compositions of grain maize (Zea mays L. cvs. DKC 5783 F1). The experiment was carried out in a randomized block design with three replications, and sodium selenate (Na2SeO4) was applied at eight different levels (0, 5, 10, 15, 25, 50, 75, 100 g Se ha−1) from the foliar when the maize plant reached 50–70 cm in height. Applications did not statistically affect yields and biomass, the contents of total nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), manganese (Mn), zinc (Zn), boron (B), and molybdenum (Mo), but it affected Se content. The total Se levels varied between 27 and 523 µg kg−1, the highest value was obtained from 100 g Se ha−1 application. When the amount of foliar-applied Se was increased from 0 to 100 g Se ha−1, the Se content increased by 19.37-fold and Se accumulation increased by 19.30-fold. Se recovery showed no significant change across the Se rates with an average of 37.01%. Foliar selenium application showed a significantly greater potential for increasing the Se level in grain maize, with 1 g of Se ha−1 increasing the grains by 5.23 µg kg−1. In this study, the Se content of maize grain increased with foliar selenate application. For human Se nutrient, it would be necessary to consume more than 100 g of maize (dry weight) per day with the foliar selenate application to maize.