Inheritance of traits associated with shootfly resistance in Rabi Sorghum (Sorghum bicolor (L.) Moench)

Abstract

Generation mean analysis involving six generations (P1, P2, F1, F2, B1 and B2) of four crosses associated with shootfly resistance was evaluated with the objectives to estimates the nature and magnitude of gene actions involved in control of the traits imparting to shootfly resistance in rabi Sorghum. Six diverse parents were selected and intermated to obtain six generations of four crosses viz., BJV74 x RSV1093, RSV1006 x RSV458, RSV1098 x RSV1003 and RSV1006 x RSV1093 for shootfly tolerance. The joint scaling test for almost all the characters was found highly significant in all the crosses indicating inadequacy of additive-dominance model and presence of higher order interactions. Additive, and additive x additive as well as dominance x dominance gene interactions were found in control of number of eggs per plant, per cent plant having egg and per cent dead heart, while dominance and dominance x dominance gene interactions were found in control of number of plant height at maturity, number of leaves per plant and grain yield per plant traits associated with shootfly resistance. Dominance x dominance (l) interaction was predominantly made significant contribution for plant height at maturity, number of leaves per plant and grain yield per plant. The parent RSV1006 followed by RSV1098 (P1) and RSV1093 followed by RSV458 (P2) parents which could be considered in developing shootfly tolerant genotypes. The traits governed by additive gene action, simple selection would be effective for crop improvement, while for the traits governed by dominance gene action, the better option would be adoption of heterosis breeding. Duplicate type of epitasis observed allmost all the crosses as well as all the traits associated with shootfly resistance.