Suppression of Orobanche cernua on tomato with Benzothiadiazole and its enzymatic changes

Benzothiadiazole (BTH) is as an elicitorwith potential to induction of resistance in some plants. In this research, the effect of different concentrations of BTH (0, 10, 100, 500 mg/ l) for induction of resistance in tomato against Orobanche cernua Loeflwas investigated. For following experiment in greenhouse condition, Early Urbana(EU) and Super Chef respectively the most tolerant and sensitive cultivars were selected. Before transplanting of tomato into contaminated pots with 20 mg broomrape seeds, the roots of plant were soaked in BTH for an hour. Also fifteen days later, the seedlings were irrigated with BTH. Growth parameters of tomato plants and pathogen were assessed 3 months later. The results demonstrated that all concentrations of BTH and tolerance variety were effective in inhibition of pathogen. The best broomrape controls were recorded by 100 percent at 100 and 500 mg/l on EU cultivar. The activity of the enzyme phenylalanine ammonia lyase (PAL) and peroxidase (POX) at 24, 48, 72 and 96 hours were estimated after irrigated plants with BTH. The results showed that there was a significant effect of the concentrations of BTH and pathogen on the activity of PAL and POX enzymes that are involved in plant defense mechanisms. The highest enzymatic activity was obtained in EU at concentration of 500 mg/l in the presence of O. cernua. In conclusions, the use of BTH commercial compounds as plant defense activator is a new, simple strategy to control broomrape and compatible with the environment for the sustainable agriculture.