Abstract

West African okra occurs in wild and unselected variants in Nigeria but farmers desire stable and high-yielding cultivars. Twenty-five West African okra genotypes from diverse geographical backgrounds were evaluated in five different environments for stability of performance. Performance was measured by number of days to 50% flowering, number of pods per plants, number of seeds per pod, plant height at maturity and seed yield per plant. A regression method, Additive main effects and Multiplicative Interaction (AMMI) and Genotype main effect and genotype x environment Interaction (GGE) were employed in the evaluation. Joint regression and AMMI analyses showed significant (P< 0.01) G x E interaction with respect to seed yield, and both identified NGAE-96-0060 and NGAE-96-0063 as stable genotypes. The AMMI and GGE biplot analyses are more efficient than the Eberhart and Russell analysis. The GGE biplot explains higher proportions of the sum of squares of the GxE interaction and is more informative with regards to environments and cultivar performance than the AMMI analysis. GGE-biplot models showed that the five environments used for the study belonged to three mega-environments with environment 2 (Upland, 2007) being the most representative and most desirable of all. The GGE results also confirmed NGAE-96-0063 as being stable with NGAE-96-04 as the most stable. NGAE-96-04 was identified as most superior genotype in terms of yield and stability of performance and could be recommended for cultivation.

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