Inheritance of Resistance to Bacterial Wilt (Ralstonia solanacearum) in Pepper (Capsicum annuum L.)

Six lines (KC350-3-4-2, KC351-2-2-2-4, KC980-3-1, KC995-2-1, KC999-3-1, KC1009-3-2) resistant to Ralstonia solanacearum, each derived from different resistance sources, were crossed to 5 susceptible cultivars or lines (Chilbok - 1, Chilbok - 4, KC201-1, KC201-7, KC256) to study the inheritance of resistance in Capsicum pepper. The relative importance of additive, dominance, and epissasis on the resistance trait was studied by generation means analysis by developing six generations viz., P-1, P-2, F-1. F-2, BC1, and BC2. The parents and their progenies were divided into 2 parts and separately inoculated with R. solanacearum isolates collected in Miryang and Sangju, Korea from 30-day-old seedlings in the greenhouse maintained from 25-25 degrees C. Resistance to R. solanacearum in pepper (C. amuum) was a quantitative character, governed by oligogenic or polygenic inheritance. Depending on the bacterial isolates inoculated and plant materials, resistance genes with low to medium heritability were exposed to the plants from partial dominance to recessive. Additive effects estimated from all crosses inoculated by different bacterial isolates were highly significant from zero. The large and positive value of additive effects indicated that predominance of additive effects were governed in the studied trait. However, under very high bacterium virulence, dominance effects seemed more important and all dominance (h) and dominance x dominance interaction (1) effects of all crosses were in opposite signs, indicating duplicate epistasis. This evidence suggests that the inheritance of bacterial wilt resistance in peppers is complicated.