Boosting protein crops in Europe: enhancing lupin nutritional value through selenium biofortification

Introduction Lupin is gaining increasing attention in Europe as a sustainable protein source due to its high protein content, resilience, and suitability for low-input farming systems. Agronomic biofortification with selenium (Se) offers a straightforward strategy to enhance crop nutritional quality. Methods A two-season field experiment (2021/22 and 2022/23) was conducted in Southwest Spain using a split-plot design, with genotype as the main plot and Se treatment as the subplot. Three lupin species ( Lupinus luteus, L. albus , and L. angustifolius ) were evaluated under four Se rates (0, 10, 20, and 40 g Se ha -1 ). Agronomic performance, grain nutritional composition, and Se accumulation were assessed. Results Selenium application significantly increased Se accumulation in lupin grains but did not affect grain yield or nutritional composition, which were mainly influenced by season and genotype. All species showed a linear increase in grain Se concentration with increasing Se doses, with L. luteus exhibiting the highest accumulation. L. albus achieved the highest average grain yield (2036.3 kg ha -1 ), followed by L. angustifolius (1039.0 kg ha -1 ) and L. luteus (642.3 kg ha -1 ). In contrast, L. luteus showed the highest protein content (48.4%), followed by L. albus (42.8%) and L. angustifolius (29.8%). Discussion These findings demonstrate that selenium enrichment of lupin grains through agronomic biofortification is feasible, although strongly influenced by genotype and environmental conditions. The results highlight the potential of lupins as alternative protein crops in Europe, with L. albus combining superior yield performance and high protein content.