Agronomic Performance and Stability of Fall Armyworm (Spodoptera frugiperda) Tolerant Maize Single Cross Hybrids Across Environments in Uganda

Abstract

Fall armyworm (FAW) [Spodoptera frugiperda] is a new pest in sub-Saharan Africa (SSA), first reported in 2016, and has fast become a pest of economic importance, causing losses of approximately 2.5–6.1 billion U.S. dollars in the region. Developing FAW-resistant varieties presents an economically sustainable solution to mitigate this challenge. The objective of this study was to identify maize single-cross hybrids (SCH) with high yield and stability under natural FAW infestation. This study assessed 94 SCH created by crossing three FAW-tolerant inbred lines with storage weevil-resistant and elite inbred lines. The 94 SCH with 5 yield checks were evaluated using a 9 × 11 alpha lattice design, with two replications across three environments. Analysis of variance revealed highly significant differences among genotypes for grain yield (GY) and FAW resistance across environments. Genotype-by-environment interactions (GEI) and stability analyses were conducted using additive main effects and multiplicative interactions (AMMI) and genotype + genotype-by-environment interaction effect (GGE) models to select promising genotypes. Results showed significant differences for genotype, environment, and genotype-by-environment interaction. GEI contributed a great percentage (24.2%) of the total variation observed for FAW resistance; for GY, environmental effect contributed more (39.26%) to GY than GEI (16.23%). Stability analysis using GGE identified Entry 65 (CKDHL166087/CZL15088) as the preferred genotype with a mean yield of 5.07 t/ha under FAW pressure. Across environments, entries 100 (CML566/CML543), 65 (CKDHL166087/CZL15142), 81(CKDHL120348/CKLTI0043), 66 (CKDHL166087/CZL15123), and 23 (CKSBL10008/CKDHL1800803) were stable and had high mean yield performance under natural FAW infestation. The study demonstrates the potential of using existing genetic material to develop high-yielding varieties under high FAW pressure. Further evaluation of promising SCH under artificial and diverse growing conditions is needed. These hybrids could be used to generate a tolerant three-way cross with other inbred lines.