Investigation the performance and biological control of the various tomato cultivars against the bacterial wilt disease (Ralstonia solanacearum)

Bacterial wilt caused by Ralstonia solanacearum is one of the most destructive disease which negatively affects the tomato production worldwide. Considering the importance of the disease, searching for resistant varieties and using biological control agents could be effective approaches in reducing the damage of the pathogen. In this study, the cultivars including Super CH, falat-111, Peto, Falkata, Queen and Early Urbana were studied. The experiments were conducted with completely randomized factorial design with a disease factor in two levels as inoculated and not inoculated. Seven cultivars (treatments) with four replicates were evaluated. Statistical analysis were performed using SAS software. The antagonistic strains of Bacillus subtilis B7, Pseudomonas flourecsens CHAO and Trichoderma harzianum T.BI and mobil cultivar were utilized. In vitro anti-bacterial evaluations were conducted and T. harzianum T.BI and B. subtilis B7 showed 3 and 5 mean distance of inhibition zone respectively but P fluorescens CHAO showed no inhibition effects. The results of means comparison showed that the stem length of cultivar Queen had the lowest reduction while the highest reduction in stem length was related to the cultivar early urbana. Regarding the fresh weight, the minimum reduction was related to cv Queen while the maximum ones were relevant to cvs Super CH, falat and Falkata cultivars. Moreover, the minimum decrease of dry weight was associated with the Queen cultivar.The results of using antagonists showed that T. harzianum T.BI and B. subtilis B7 regarding index of stem length, shoot and root fresh weight, dry weight of roots and shoots are the best options to control bacterial wilt.