Screening of Tomato Cultivars through Qualitative and Quantitative Evaluation for Bacterial Canker (Clavibacter michiganensis subsp michiganensis) in Open and Protected Conditions

Twenty-five tomato cultivars were evaluated in two growing season and two growth conditions against bacterial canker (Clavibacter michiganensis subsp michiganensis) at the Vegetable Research Centre (V.R.C.) Pantnagar. The experiment was completely randomized in controlled conditions (glass house) and randomized block design in open field conditions. The experiment was done by two methods, first, through alteration in the enzymatic concentrations of the ROS-scavenging enzymes estimation (quantitative method) and second, through symptom expression (qualitative method) in open and protected conditions. Out of the 25 cultivars screened between September 2015–January, 2016 for the first growing season (5-35ºC), disease appearance was observed in cultivar Pusa Ruby (21.60%) followed by Rohini (20.60%) and Arka Vikash (19.56%) in open field conditions. In the protected crop conditions of glasshouse the cultivar with maximum disease appearance was Arka Vikash with a disease severity of 24.1% followed by Rohini (19.50%) and Pusa Ruby (18.00%). During the second growing season (24-45°C), Feb 16–June 16, all the cultivars exhibited susceptible disease reaction in both the open field and glass house. The cultivar screening resulted in Phule Raja, a potential cultivar with resistance by delayed expression of the pathogen presence at the end of the growth period (May), while the remaining 24 varieties exhibited susceptible disease reaction early in the growth period.