Evaluating the Effects of Sclerotinia Rot Resistant Genotypes on Different Indian Mustard Traits and Yield Using Generation Analysis

Sclerotinia stem rot caused by the pathogen Sclerotinia sclerotiorum is a serious threat to Indian mustard cultivation and causes up to 90% loss in seed yield. The present investigation was conducted to understand the inheritance pattern of Sclerotinia stem rot resistance through generation mean analysis, as a first step in addressing the problem. Six generations i.e.., P1, P2, F1, F2, BC1P1 and BC1P2 of a cross between a sclerotinia stem rot resistant genotype viz., RH 1222-28 and two susceptible genotypes viz., EC 766300 and EC 766123 were evaluated for sclerotinia stem rot resistance, yield and its component traits at timely sown conditions. For resistance assessment, plants were artificially inoculated with 5 days-old pure culture of S. Sclerotiorum at the post-flowering stage and stem lesion length was measured (cm) from each inoculated stem at 20 days after inoculation. Sclerotinia stem rot resistance, seed yield, and their component traits were adequately explained by the epistatic interaction model. Furthermore, additive, dominance, and epistatic gene effects were implicated in the expression of resistance, yield, and traits associated with it. In order to generate Indian mustard cultivars with high yielding potential and resistant to sclerotinia stem rot, reciprocal recurrent selection would be the most successful method.