Metabolite‐Mediated Nutritional and Agronomic Responses of Extra‐Early Biofortified Maize ( <scp> <i>Zea mays</i> </scp> L.) to Fall Armyworm ( <scp> <i>Spodoptera frugiperda</i> </scp> ) Infestation

ABSTRACT Fall armyworm (FAW) is a major constraint to maize ( Zea mays L.) production and nutritional quality in sub‐Saharan Africa, necessitating the development of extra‐early cultivars with stable grain yield, pest tolerance and enhanced nutritional quality. This study evaluated genetic variability and selection efficiency among 20 extra‐early provitamin A‐quality protein maize (PVA‐QPM) inbreds under natural FAW infestation across two cropping seasons (2023 and 2024) at Oke‐Oyi, Nigeria. Significant ( p < 0.01) genotypic, environmental and genotype × environment interaction effects were observed for grain yield, FAW severity, yield stability index and nutritional quality traits. Superior inbreds, including TZEEIORQ 43, TZEEIORQ 490 and TZEEIORQ 29, combined high grain yield (2720–2750 kg ha −1 ) with low FAW severity (3.2–3.4) and high yield stability (0.92–0.93). These genotypes exhibited elevated β‐carotene (8.1–8.3 μg g −1 ), tryptophan (0.86–0.87 g 100 g −1 ), iron (39–40 mg kg −1 ) and zinc (27–28 mg kg −1 ). Genotypic variation for these traits was consistent across both seasons. Untargeted LC–MS metabolomic profiling identified accumulation of chlorogenic acid, ferulic acid, β‐carotene, tryptophan, glutathione, malic acid and linolenic acid. These metabolites were associated with phenylpropanoid, flavonoid, amino acid and jasmonate‐linked pathways. Multivariate analyses revealed structured associations among metabolite profiles, FAW infestation response, grain yield and nutrient composition. Results demonstrate genetic variability among inbreds for agronomic, nutritional and metabolic traits under FAW pressure, supporting improvement of FAW tolerance, yield stability and nutritional quality in extra‐early PVA‐QPM for resilient sub‐Saharan Africa.