Genotype × environment interaction effects on pod yield and pod number in West African Okra

ABSTRACT

As year-to-year weather fluctuation increases, the need for better understanding of their effects on crops becomes ever more pressing. Genotype × environment (G × E) interactions for pod yield and pod number were assessed in a set of 25 West African okra genotypes that were cultivated in four successive years (otherwise called environments) through field trials, arranged in a randomized complete block design, with three replicates. Significant G × E interactions in measured traits were detected, suggesting that selection for stable genotypes, with respect to these traits must be environmental specific. Consequently, additive main effects and multiplicative interaction model was applied to dissect G × E interactions. For pod yield, the highest percentage (38.4%) of the treatment sum of square was attributable to genotypes followed by G × E interactions (36.0%) and environment (25.6%), indicating predominance of genotypic variation for this trait. Conversely, prevalence of G × E interactions was observed for pod number. The biplots of the grand mean and IPCA 1 score revealed that the environments tended to discriminate genotypes in dissimilar fashion. Rainfall, relative humidity, wind speed and soil temperature were identified as strong driving forces for development and growth, affecting pod yield. The identified genotypes could be suitable candidates for further study.

KEYWORDS:

• Biplots
• environmental factors
• genotype × environment interactions
• multi-environmental trials
• Pod yield

Acknowledgments

The author acknowledges and appreciates the support of National Centre for Genetic Resources and Biotechnology, Ibadan, Nigeria for providing West African okra accessions used in the study. Also, the technical assistance of Prof. O. J. Ariyo is gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author.