Genetic expression of fruit physico-chemical characters in bitter gourd inter-specific crosses

ABSTRACT

Improvement of bitter gourd (Momordica charantia L.) has been constrained by a lack of adequate information on genetic control of fruit characteristics. Generation mean analysis was employed to understand the nature of gene action involved in conditioning of the fruit physico-chemical characters length, diameter, weight, total chlorophyll, β-carotene, and ascorbic acid contents, utilizing two contrasting crosses involving botanical varieties of bitter gourd. In both crosses, dominance, additive, and most of the epistatic components, were significant indicating a complex nature of inheritance for all characters under study. The dominance × dominance interaction effect was larger than the additive × additive effect. Duplicate epistasis in both crosses indicated hindrance in advancement through selection. Most characters are under control of non-additive gene action, and the magnitude of additive component was lower than dominance × dominance component; selection for most characters might be difficult. Dominance estimates indicated there would be less likelihood of isolating genotypes with fruit of increased size and having high β-carotene content from the crosses involving small-fruited M. charantia var. muricata Willd. as a parent because small fruit exhibited dominance. There would be a possibility of isolating genotype with fruit having high ascorbic acid content in segregating generations of these cross combinations. Selection for improvement of fruit physico-chemical characters should be delayed to later generations of segregating populations in bitter gourd. The modified bulk method of selection is recommended, in which selection is performed after attaining homozygosity for maximum heterozygous loci.

KEYWORDS:

• Momordica charantia
• gene action
• generation mean analysis

Acknowledgments

The study supported financially by the Board of Research in Nuclear Sciences, Bhabha Atomic Research Centre, Trombay, India.