Combining ability for resistance in peanut (Arachis hypogaea) to Peanut bud necrosis tospovirus (PBNV)

The combining abilities of field resistance to peanut bud necrosis disease (PBND) caused by Peanut budnecrosis tospovirus (PBNV) were examined to understand the type of gene action governing resistance to the disease, and to identify peanut lines suitable for use as parents in a PBND-resistance breeding programme. The F, and F, progenies from a six-parent diallel cross and their parents were evaluated under field conditions. They were assessed for disease incidence at 30, 40, 50 and 60 days after planting (DAP), and reactions of the lines to the disease could be best differentiated at 50 and 60 DAP. Results indicated highly significant general combining ability (GCA) effects for PBND incidence in F-1 and F-2 generations. Specific combining ability (SCA) and reciprocal effects were also found to be significant, but their relative contributions to variation among crosses were much less than those of GCA effects. These results suggested that the type of gene action governing resistance to PBND was mainly additive, and selection for PBND resistance in these populations should be effective. Strong correlation coefficients between parental means and GCA effects for disease incidence were seen in both F-1 and F-2 generations, suggesting that per se performance of the parental line could be used as a predictor of the capability of the line to transmit its PBND-resistant attribute to progenies. The reciprocal effects were in favour of using resistant lines as female parents. The peanut lines ICGV 86388, IC 10 and IC 34 were found to be suitable for use in a PBND-resistance breeding programme.