Screening of tomato genotypes against bacterial wilt (Ralstonia solanacearum) and validation of resistance linked DNA markers

Tomato yield losses are mainly caused due to bacterial wilt (Ralstonia solanacearum) throughout the world. The disease management is mainly done through chemicals which lead to health risks. Among non-chemical strategies, development of resistant varieties can be a good alternative. The present study was conducted to screen the fifty seven different tomato genotypes against bacterial wilt using artificial inoculation technique under greenhouse conditions. The plants showing symptoms were examined using ooze test. Morphological and molecular characterization of the bacterial strains isolated from infected plants was carried out and bacterial phylotype I was determined using phylotype-specific multiplex PCR. The bacterial-infected tomato genotypes were categorized into highly resistant, resistant, moderately resistant, moderately susceptible, susceptible, highly susceptible and extremely susceptible lines. Seven tomato genotypes viz.RIL-118, Indam-1004, Arka Samrat, PKM-1, PED, EC-802390, and EC-816105 were found highly resistant to bacterial wilt. These genotypes were also evaluated for plant growth, yield and yield-related traits and fruit quality traits under field conditions. Maximum production (2533 g/plant) was observed for the genotype Arka Rakshak followed by EC816156 (2486 g/plant).while genotype EC815157 (200 g/plant) exhibited lowest production. In addition, fourteen bacterial wilt linked markers were validated for these genotypes where SCAR marker, SCU176-534 was found to be linked with the bacterial wilt resistance significantly. This study will be significant and useful in increasing tomato production and to develop new resistant tomato varieties through marker assisted breeding.