Combining ability and genetic architecture of yield and quality traits in bottle gourd (Lagenaria siceraria (Mol.) Standl.)

Abstract

Bottle gourd (Lagenaria siceraria (Mol.) Standl.) is an important cucurbitaceous vegetable crop widely cultivated in tropical and subtropical regions due to its high nutritional value, adaptability, consumer preference and potential for yield improvement through heterosis breeding. The genetic improvement of bottle gourd requires a clear understanding of the relative contribution of additive and non-additive gene that govern yield and quality traits. The present investigation assessed general combining ability (GCA) and specific combining ability (SCA) in seven diverse parental lines and their 21 F₁ hybrids developed through a full diallel mating design (excluding reciprocals). The experimental material comprising seven parental lines and 21 F₁ hybrids was evaluated in a randomised complete block design (RCBD) with 3 replications for 10 agronomic and quality traits. Analysis of variance (ANOVA) revealed significant GCA and SCA effects for most traits, including fruit length (83.05 and 10.80), fruit girth (20.31 and 3.79), yield (183.2 and 760.3) and total soluble solids (0.11 and 0.19), respectively, with SCA variance predominating for yield and its major components, indicating the importance of dominance and epistatic interactions. Among parents, BRBG 65 exhibited desirable GCA effects for primary branches per vine (1.06), vine length (0.27) and fruit length (3.20), while BRBG 190 showed positive GCA effects for fruit girth (1.50) and yield (21.65), identifying them as superior general combiners for yield and quality attributes. Among the hybrids, BRBG 65 × Punjab Komal recorded high positive SCA effects for yield (16.25), fruit girth (2.81) and earliness for first fruit harvest (-4.82), whereas BRBG 51-2 × BRBG 190 exhibited high and desirable SCA effects for fruit length (6.89) and yield (10.16). The hybrid BRBG 21-2 × Pusa Naveen also showed significant positive SCA effects for yield (9.75) and total soluble solids (0.71), demonstrating substantial heterotic potential. The findings of the present study indicated the predominance of non-additive gene action and suggested that hybrid breeding could be effectively utilised for yield enhancement in bottle gourd. Furthermore, the identified superior parents and promising hybrids may serve as valuable genetic resources for future hybrid development and population improvement programmes under eastern Indian agro-climatic conditions.