Genotype-Environment Interaction in Maize (Zea mays) Varieties Grown Across Agroecological Zones in Borno and Taraba States

Understanding genotype-environment (GxE) interaction is fundamental to crop improvement and varietal recommendation in Nigeria, where agroecological conditions vary markedly between zones. Maize is a staple crop cultivated across diverse environments from the Sudan savanna of Borno State in the North East to the Guinea savanna of Taraba State in the same region. This study evaluated GxE interaction for yield-related traits in selected maize varieties across these contrasting environments. Six improved open-pollinated maize varieties released by the International Institute of Tropical Agriculture were planted in randomised complete block designs at two sites in each state during the 2023 cropping season. Agronomic data including days to anthesis, plant height, ear length, grain weight per cob, and grain yield per hectare were collected. Analysis of variance and GGE biplot analysis were applied to assess stability and adaptability. Results identified varieties with broad adaptability across both environments and others with specific adaptation to high-rainfall environments in Taraba. The findings offer practical guidance to extension workers and smallholder farmers in choosing appropriate varieties for their specific agroecological niches in North East Nigeria. Keywords: genotype-environment interaction, maize, Borno State, Taraba State, GGE biplot