Heterosis and Combining Ability in Bottle Gourd

Combining ability and heterosis studies were carried out through line x tester using 10 parents with 3 testers in two seasons at NDUAT, Faizabad. The high manifestation of heterosis for marketable fruit yield per plant was evidenced by the superiority over better parent in both the environment. The lowest magnitude of heterobeltiosis and standard heterosis was lower in rainy season as compare to summer season. In the days first harvest range of upper and lower limits of heterobeltiosis as well as standard heterosis were more or less similar in both seasons. The range of heterosis identity in number and of crosses exhibiting significantly negative and positive over standard check and better parent showed considerable differences from summer season to rainy season. This indicated that the genotype x environment interaction played an important role in expression of heterotic expression in F1s for all the characters under study. The expression of significant and desirable heterobeltiosis and standard heterosis in general and specific combining ability effects was also examined. In case of marketable yield per plant the crosses exhibiting positive and significant heterobeltiosis and standard heterosis were found to posses positive, negative and average sca effects for this character in almost same frequencies. However majority of crosses sowing positive and significantly heterobeltiosisand standard heterosis for marketable fruit yieldper plant inthe two environments involved high x general combiner parent followed by high x low and high x medium combinations.