Abstract

Five tomato cultivars were studied for inheritance of bacterial wilt resistance. Lines AVTO1429, AVTO1424, and AVTO1314 have the resistance gene, Roma VF lacks the resistance gene, and Valoria Select is claimed to have resistance but has not been evaluated. The study, which was carried out in a split plot design, involved six generations and backcrosses that were conducted in a greenhouse and a field. Artificial inoculation of Ralstonia solanacearum was carried out in greenhouse. Parental lines AVTO1429, AVTO1424 and AVTO1314 had the lowest incidence of 37.78, 26.67 and 26.67%, respectively while Roma VF had the highest at 95%. F1 hybrids had lower incidence of ≤ 33.33% in all the crosses. Cross F1 x Parent 2 (BC2) had significantly lower disease incidence and severity compared to F2 hybrids, F1 x Parent 1 (BC1) and P1 (Roma VF) in all crosses. Computation of gene effects showed significant additive effects of 1.941 for cross Roma VF x AVTO1429 and 1.925 for cross Roma VF x Valoria select at p<0.01. Dominance effects, additive x additive, additive x dominance and dominance x dominance interaction in all the crosses were significantly different at p<0.01. The important gene effects for bacterial wilt resistance inheritance was in additive and dominance-additive portions which implied that the resistance trait was inherited.

Key words: Ralstonia solanacearum, tomato, resistance trait, inheritance, bacterial wilt.