Differentiation of agronomic, β-carotene, and tryptophan traits in provitamin A quality protein maize under fall armyworm infestation

Abstract

Fall armyworm (FAW) infestation poses a critical constraint to maize production across sub-Saharan Africa, with disproportionate impacts on extra-early maturing genotypes that are vital for ensuring food security in climate-sensitive and resource-constrained environments. This study provides the first systematic evaluation of extra-early provitamin A quality protein maize inbred lines for grain yield, biofortification traits, and FAW resistance under natural infestation. It employs multivariate analysis to integrate earliness, nutritional quality, and pest resilience for climate-smart maize breeding. Field evaluations were conducted during the 2023 and 2024 rainy seasons at Oke-Oyi, Nigeria, using a randomized complete block design. Multivariate analysis of variance revealed highly significant differences among inbred lines for key agronomic and nutritional traits. Notably, top-performing genotypes such as TZEEIORQ 14 exhibited grain yield advantages of 25.9% and 41.7% over standard checks. Multiple inbred lines surpassed the biofortification threshold of 12 µg/g for β-carotene and consistently demonstrated elevated tryptophan concentrations relative to the standard checks. Canonical discriminant analysis grouped the inbreds into distinct clusters, with grain yield, β-carotene, and tryptophan emerging as the primary discriminating traits. Conversely, leaf damage score and anthesis–silking interval were the most negative contributors to genotype separation. Inbreds TZEEIORQ 5, 10, 11, 14, and 18 emerged as promising candidates for breeding programmes aimed at enhancing FAW tolerance, nutritional quality, and grain yield. These findings demonstrate the effectiveness of multivariate tools in deciphering trait interrelationships and facilitating the selection of elite genotypes for sustainable maize improvement.