Sulphur and selenium foliar fertilization enhances the protein profile and reduces anti-nutritional compounds in common wheat

Context or problem Enhancing the nutritional and technological quality of wheat is increasingly critical in the face of global micronutrient deficiencies. Traditional crop improvement has prioritized yield over nutritional value, resulting in staple crops with limited concentrations of essential nutrients and higher levels of antinutritional factors. Foliar fertilization strategies, particularly with micro- and macronutrients, such as selenium (Se) and sulphur (S), respectively, have emerged as promising solutions to improve both nutrient content and functional quality in wheat grain. Objective or research question This study aimed to investigate the effects of foliar-applied S and Se on yield, protein composition, mineral bioavailability, and dough properties in two common wheat (Triticum aestivum L.) varieties. Bologna and Sieve were selected as representative modern and old wheat varieties, respectively. Methods A split-split-plot field experiment was conducted across two growing seasons under rainfed conditions in Tuscany, Italy. Treatments included five Se application rates (0–20.54 g Se ha⁻¹ as sodium selenite) and three S levels (0, 3.2, and 6.4 kg S ha⁻¹ as wettable S), applied at the watery ripe and booting stages, respectively. Bologna and Sieve were evaluated for agronomic performance, grain composition, and technological qualities. The key traits measured included yield components, free asparagine, phytic acid (Phy), protein fractions, mineral concentrations, dough strength and dough tenacity/extensibility ratio. Results Grain yield was not significantly affected by either Se or S treatments, reinforcing the dominant role of genotype. Protein concentration was strongly influenced by variety (86.05 % of total variation) and moderately by Se rate. S showed no significant effect on total protein but altered the composition, decreasing gliadin and increasing glutenin content. This shift modified the gliadin-to-glutenin ratio, with potential implications for dough rheology. The dough strength and dough tenacity/extensibility ratio were primarily genotype-dependent, though S-induced variety-specific responses. Phy, a key anti-nutrient, was significantly reduced by increasing Se levels. The resulting decline in Phy:Se, Phy:Fe, and Phy:Zn molar ratios indicate improved mineral bioavailability. Free asparagine, a precursor to the carcinogen acrylamide, was most affected by S treatment, which accounted for 82.5 % of the variation. Se further reduced free asparagine, particularly under adequate S conditions. Conclusions This study demonstrates that while genotype was shown to predominantly control wheat quality traits, Se and S foliar applications significantly enhanced the nutritional value and processing quality of wheat grain. Implications or significance These findings support the adoption of targeted foliar fertilization strategies combining Se and S to improve wheat quality. Future research should investigate varietal responses under broader environmental conditions and refine application timing to maximize benefits.