Stability in performance of normal and nutritionally enhanced highland maize hybrid genotypes in Eastern Africa

Maize (Zea mays L.) is a major crop in Eastern Africa in terms of production, consumption and income generation. Although highland ecologies in Eastern Africa have high potential for maize production, few varieties have been developed. Breeding efforts have been also concentrated on Quality Protein Maize (QPM) as a viable and cheaper method to alleviate malnutrition. Twenty conventional and 20 QPM three-way hybrid genotypes were developed and evaluated in a randomized block design across 11 and 8 environments in Ethiopia, Kenya, Rwanda and Uganda in 2010. The objective was to identify superior and stable varieties from genotypes. Data were recorded on major agronomic traits (grain yield t ha-1). Additive main effects and multiplicative interactions (AMMI) statistical model was used to assess stability in performance for grain yield. Combined analysis of variance across environments indicated highly significant differences among non-QPM and QPM genotypes. Variations due to environment and genotypexenvironment (GxE) were suggesting genotypes performed differently across environments. Environments of Gisozi, Holleta, Kongoni and Kapchorwa were favourable and stable while Kulumsa was favourable but unstable. Other environments were of medium to low potential. The AMMI analysis ranked 5 non-QPM genotypes were with above-average yield (6.34 t ha) and 8 for stability performance across environments. While for QPM 3 genotypes were yielded better than best check (6.941 ha) and 7 genotypes were stable. Genotype 9 (7.15 t ha) was the only non-QPM genotype with yield better than the best check across environments. The information obtained will help to streamline highland maize testing programs in the region