Production environment effect on agronomic performance of okra breeding lines and their F₂ populations

ABSTRACT

The type of production environment can affect agronomic performance of West African okra [Abelmoschus caillei (A.Chev) Stevels] breeding lines and their progenies. The study was conducted to (1) compare agronomic performance of West African okra lines and F₂ populations under upland and bottomland environments, (2) identify sources of genes with potential to improve pod yield, (3) estimate genetic and phenotypic correlations for evaluated traits, and (4) estimate expected response to selection for pod yield and other agronomic traits through intergeneration correlation and regression. Twenty-three genotypes (9 F₂ populations and their corresponding 14 parents) were grown in two production environments at the research farms of the Federal University of Agriculture, Abeokuta, Nigeria. Results were analyzed using principal component analysis, correlation and regression analyses. Unique trait profiles in genotypes responses to production environments occurred. Most genotypes indicated adaptation to the bottomland environment by reducing days to physiological maturity. Hybrid AGA97/066/5780 × NGAE-96–-0062-2, which combines early maturity with superior expression of pod yield between production environments, may be used to improve earliness in West African okra. Principal component analysis revealed three major factors that explained more than 66% and 69% of interrelation among traits in upland and bottomland, respectively. Changes of genotypic correlations between pod yield and other agronomic traits occurred between environments indicating the influence of environmental factors to trait correlation. A significant, positive correlation, and regression coefficients, between parents and the F₂ generation for pod yield occurred between production environments, indicating the effectiveness of selection for pod yield in the early segregating generation. Generally, bottomland production environment offered a higher potential for agronomic trait expression in breeding lines and F₂ population of West African okra.

KEYWORDS:

• Abelmoschus caillei
• correlation
• hybridization breeding
• regression

Acknowledgments

We are grateful to the National Center for Genetic Resource and Biotechnology and Centre for Environment, Renewable Natural Resources Management, and Development, Ibadan, Oyo State, Nigeria for the West African germplasm provided for the study. Special thanks is expressed to Mr. O.J. Olalekan for assistance with data collection, and several anonymous reviewers for helpful comments on an earlier draft of this manuscript.