Abstract
Seven papaya genotypes- Shahi, P020, P045, P092, Pusa Nanha, Pusa Dwarf and CO.2 of which the first four are local genotypes and the rest are exotic, were crossed in all possible combinations without reciprocals in a diallel fashion. It was done to know the nature and magnitude of heterosis, obtain information on combining ability of parents and their crosses and the pattern of inheritance of some vegetative and fruit characters in papaya. The study was conducted at the Central Research Station of Bangladesh Agricultural Research Institute, Gazipur during the period from September, 1993 to March, 1996. Both positive and negative heterosis at varying levels were recorded in all the characters under study. The highest yield heterosis was recorded in the cross Shahi x Pusa Nanha (43.24%) over better parent followed by P092 x C0.2 (39.04%) and P045 x C0.2 (37.77%). Heterotic effect up to 26.72% was recorded in the cross Pusa Nanha x Co.2 for total soluble solids (TSS). In respect of plant height the highest negative heterosis was recorded in the cross P020 x Shahi (20.25%) over mid-parent.
The parents P020, Shahi and Pusa Nanha were estimated as good combiners and the cross P020 x Pusa Nanha exhibited the highest positive sca effects followed by Pusa Nanha x Pusa Dwarf and Shahi x Pusa Nanha for fruit yield per plant. High gca effects in the desirable direction for total soluble solids were shown by the parents P020, P045 and Shahi and the promising crosses were Pusa Nanha x Co.2, P092 x Co.2 and P092 x Shahi.