Genetic Study for Earliness in Yard Long Bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdcourt)

The diallel analysis (without reciprocals) of F₁ hybrids of yard long bean showed significant difference among parents and hybrids for days to first flowering and days to harvest. The cross combination Kakkamoola Local x Palayam Local (VS 50 x VS 38) exhibited maximum negative heterosis over better parent, mid parent and standard parent respectively for days to first flowering. For the days to harvest Kakkamoola Local x Aripra Local (VS 50 x VS 29) showed maximum negative heterosis over better parent and mid parent, whereas Kakkamoola Local x Pattom Local (VS 50 x VS 16) was better over standard parent for days to harvest. The variance due to general combining ability and specific combining ability were highly significant which shows the relevance of additive and non additive gene action; however, non additive gene action was predominant for both the traits. The parents Kakkamoola Local (VS 50) and Thirupuram Local (VS 54) were good combiners for early flowering while Githika (VS 34), Kakkamoola Local (VS 50) and Pattom Local (VS 16) were superior for early harvest. The crosses Kakkamoola Local x Palayam Local (VS 50 x VS 38) and Kakkamoola Local x Pattom Local (VS 50 x VS 16) were identified as promising specific combiners for early flowering as well as early harvest.