Combining Ability and Gene Action Influencing Bacterial Wilt Resistance in Brinjal

Abstract

This study employed a line × tester mating design to evaluate bacterial wilt resistance in brinjal at the seedling stage. Four lines viz., L1 (SM 10), L2 (IC111010), L3 (IC89989), and L4 (IC427008) and three testers viz., T1 (IC253967), T2 (IC255756), and T3 (IC256708) were crossed to produce twelve F₁ hybrids, which, along with parents and checks, were screened at the seedling stage using the artificial root-dip inoculation method. Percent Disease Incidence (PDI) served as the criterion for resistance classification. Among all genotypes, the hybrid L3 × T1, tester T2 and the resistant check Arka Anand exhibited complete resistance, showing no visible wilt symptoms. Four hybrids namely, L1 × T2, L2 × T3, L3 × T2 and L4 × T2 along with line L3, testers T1 and T3 and the check Neelima were moderately resistant. Hybrids L1 × T1 and L4 × T1, line L4 and Haritha were moderately susceptible, while the remaining hybrids and lines showed moderate to high susceptibility. Combining ability analysis identified L2 × T3 (IC111010 × IC256708) as the most promising hybrid due to its desirable specific combining ability effect for resistance. Additive variance was low and negative, whereas dominance variance was high, confirming the predominance of non-additive gene action. The major contribution of line × tester interaction (64.12%), compared with lines (12.04%) and testers (23.83%), also emphasizes non-additive, dominance gene action and the significance of hybrid breeding as a better strategy to develop bacterial wilt resistant hybrids here.