Genetic analysis of resistance to watermelon bud necrosis orthotospovirus in watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai]

An experiment was conducted to study the genetics and nature of gene action of resistance to watermelon bud necrosis orthotospovirus (WBNV) in watermelon. The experimental materials comprised of two resistant (BIL-53 and IIHR-19) and one susceptible (IIHR-140) parents. Each of the resistant parents was crossed with the susceptible parent to develop six generations (P1, P2, F-1, F-2, BC1 and BC2) to study genetics. The results of segregation in F-2 and backcross progenies suggested that resistance is governed by a major dominant gene along with other background minor genes in both the crosses. BIL-53 was found to possess higher degree of resistance with simple inheritance and hence may be of interest to breeders. Simple selection can be effective for improving the trait in the cross BIL-53 x IIHR-140 as additive gene action is prevalent.