Variation in the phenotypic performance of top-cross fall armyworm resistant maize hybrids under rain-fed growing conditions in a derived savanna agroecology
Abstract
Fall armyworm (Spodoptera frugiperda) threatens maize production in sub-Saharan Africa. Developing maize hybrids that are resistant to fall armyworm and achieve high grain yields can enhance productivity and stability, particularly in the savanna agroecology. This study evaluated 32 maize hybrids, including commercial checks, for: (i) phenotypic performance, (ii) trait relationships among newly developed top-cross maize hybrids, and (iii) promising maize hybrids using the genotype by yield × trait (GYT) biplot analysis under natural fall armyworm infestation at the Teaching and Research farm of Ladoke Akintola University of Technology, Ogbomoso, Nigeria. The trial was laid out in an 8 × 4 α-lattice design with three replications. Analysis of variance revealed highly significant (p < 0.001) differences among hybrids, environments, and hybrid × environment interactions for grain yield and other agronomic traits. Hybrid G1 (FAWSYN-1/(TZLComp.1 C6-W-39-1-1)-B-B) had the highest grain yield of 5223.3 kg ha−1, showing a 26.8% yield advantage over the top check. Approximately 30.7% of tested hybrids outperformed the highest yielding check (G31: Oba Super 9). Grain yield showed significant (p < 0.001) negative phenotypic correlations with foliar fall armyworm damage, plant aspect, and husk cover ratings. Plant aspect showed the strongest individual association with grain yield among evaluated traits. Fall armyworm infestation significantly (p < 0.01) reduced grain yield, husk cover, plant, and ear aspect ratings. The genotype by grain yield × trait (GYT) biplot identified five hybrids (G1, G9, G21, G18, and G3) that combine high yield with moderate tolerance to fall armyworm under natural infestations. Moderate broad-sense heritability across traits suggests genetic potential but highlights environmental influence. These promising hybrids are recommended for multi-locational yield trials before farmer recommendations for the derived savanna agroecology.