Genetic architecture of biochemical traits for heterosis and combining ability in bitter gourd (Momordica charantia L.)

Bitter gourd is an important cucurbitaceous vegetable valued for its nutritional and medicinal properties. However, limited availability of superior quality hybrids has restricted its improvement for biochemical traits. The present investigation was conducted to study heterosis, combining ability and gene action governing biochemical traits in bitter gourd. Seven diverse inbred lines, namely PK-1, PK-2, PK-3, LBG-4, LBG-5, LBG-6 and P-14, were crossed in a half-diallel mating design to produce 21 F₁ hybrids, which were evaluated along with the commercial check ‘Solan Hara’ in a randomized complete block design with three replications. The hybrid P-14 × LBG-5 exhibited superior performance with significant desirable heterosis for TSS, ascorbic acid, chlorophyll, phenols, flavonoids, antioxidant activity and dry matter, while showing desirable negative heterosis for acidity, sugar content and moisture content. Combining ability analysis identified LBG-5, P-14 and PK-1 as good general combiners for improvement of quality traits. Significant and desirable specific combining ability effects were observed in hybrids P-14 × LBG-5, PK-3 × PK-2, LBG-5 × PK-2 and LBG-5 × LBG-4 for most biochemical characters. Genetic analysis revealed low GCA:SCA and predictability ratios, indicating the predominance of non-additive gene action for all traits. Dominance variance was higher than additive variance along with high broad-sense and low narrow-sense heritability estimates. The findings suggested that heterosis breeding could be effectively utilized for improvement of nutritional quality in bitter gourd and the hybrid P-14 × LBG-5 may be exploited further in future breeding programmes and commercial cultivation.