GENOTYPE BY ENVIRONMENT INTERACTIONS AND YIELD STABILITY OF MAIZE (Zea mays L.) HYBRIDS AND THEIR REACTIONS TO FALL ARMYWORM IN GAMO LOWLANDS, SOUTHERN ETHIOPIA

Abstract

There is limited information about the performances of maize genotypes under specific environmental conditions and with fall armyworm infestations in the Gamo lowlands of Ethiopia. The development of maize hybrids, which are high-yielding and relatively stable when grown in dif erent environments, is fundamental importance to boost maize production. This study aimed to assess the interaction between genotype and environment as well as determining the yield stability of maize hybrids and their reactions to fall armyworm in the Gamo lowlands of southern Ethiopia. The experiment was conducted in two dif erent locations Arbaminch and Shele for two consecutive years (2022 and 2023) cropping seasons (March-September). A total of thirty-two maize hybrids including local check (BH-546) were evaluated under field condition using a 4x8 alpha lattice design with three replications. Various agronomic traits, grain yield, and fall armyworm score data were collected. Statistical analyses were performed to determine the significance of genotypes, environments, and genotype x environment interactions. The analysis of variance result revealed significant genotype x environment interactions for fall armyworm scores and several traits related to plant and ear aspects, husk cover, and Phenological traits. However, traits such as grain yield, plant height, ear height, and ears per plant were not significantly af ected by genotype by environment interactions. In general, the result of dif erent stability parameters were dif ers in the selection of the best performing and stable genotypes. Among the tested hybrids, AS200119 and AS200121 demonstrated consistent and stable performance across the four environments. The biplot analysis revealed that Environment 1 (AM22), Environment 4 (SH23), for grain yield, and Environment 1(AM22) and 2(SH22) for fall armyworm were the most discriminating environments, while Environment 3(AM23) and Environment 4(SH23) were the most representative environment for yield performance and fall armyworm, respectively. This result showed that there were stable and superior hybrids for grain yield improvement and fall armyworm tolerance in the study area. Our study provides insight into fall armyworm larval preferences and performance on some maize hybrids, showing that there are dif erences between hybrids in these variables and the parents of those highly stable and superior hybrids can be used for variety development to enhance productivity and fall armyworm tolerance. Further research should be conducted to address comprehensive evaluation, long-term studies, environmental factors, trait analysis, and farmer part research.