GGE biplot application for adaptability of African yam bean grain yield to four agro-ecologies in Nigeria

Abstract

Genotypes respond to environments differently; therefore it is important that their response to growing environment should be investigated in order to identify most suitable genotype(s) for specific environment. The objective of this study was to understand the adaptability of some accessions of African yam bean to different agro-ecologies of Nigeria. Thirty African yam bean (AYB) (Sphenostylis stenocarpa (Hochst ex. A. Rich) Harms) accessions were evaluated for grain yield adaptability to four agro-environments in Nigeria. Genotype by environment (GE) interaction was significant (P < 0.01) for grain yield, with a range of 239.29 kg ha^-1 (TSs 89) to 4130.46 kg ha^-1 (TSs 33). Two principal component axes generated in the biplots explained 70.9% of the total variation due to the accessions and their interaction with the environments. The superior genotypes for each location were TSs82 (Ibadan), TSs116 (Mokwa), TSs24 (Ikenne) and TSs33 (Ubiaja). Three mega-environments arose from the study; namely Ikenne, Ubiaja and Mokwa (Ibadan merged with Mokwa to form a single megaenvironment). Ikenne was a more representative environment for AYB production, having a mean grain yield of 1074.53 kg ha^-1, closest to the grand mean of 1075.57 kg ha^-1. However, Ubiaja was most supportive for grain production of AYB. Some of the accessions identified with high yielding, adaptable/stable in the study included TSs101, TSs111, TSs93, TSs94, TSs57, TSs104B and TSs109.

Key Words: Accessions, mega-environment, principal components, Sphenostylis stenocarpa