Biology and Agriculture Division, Bhabha Atomic Research Centre, Trombay, Bombay-400085
Online published on 25 January, 2012.
The X-ray induced large pod mutant was crossed to the Spanish parent as well as to the virescent mutant with a view to combine useful characters.
Genetic studies on eleven characters in F2 and F3 generations showed that these characters were controlled by quantitative genes. Increased branching, leaflet length and kernel size expressed as dominant characters in F1. The subsequent behaviour of kernel size, however, was unlike its F1 expression, perhaps, due to modifying factors influencing large pod character.
Heritability values representing the amount of genetic variance available for selection, were more than 40% for all the characters excepting for yield, which had negligible variance. Hence, direct selection for improved yields was not successful.
Economically imporant characters such as, shelling %, kernel size and oil content were less influenced by environment. Therefore, it was easy to stabilise selections in them.
Phenotypic correlations showed disadvantageous associations between kernel size/oil content and pod size/shelling % resulting in a limited scope for selecting plants having large kernel with increased oil content and improved shelling %. Inspite of these associations, a few selections having large kernels, improved oil content and increased shelling % were isolated in the cross between the two mutants. This indicated the advantages of cross-breeding among the induced mutants.
