Evaluation of resistance and biochemical responses of different varieties of tomato to Dodder (Cuscuta campestris Yunck.)

Dodder is a one of the major parasitic weeds in the world. Dodder infestations reduce crop yield and increase harvesting costs. Different methods have been suggested to control of dodder, but none of them have been able to control these plants reliably. It seems that using resistant varieties is the best option to achieve this goal. In this study, resistance of 15 varieties of tomato to dodder infection (Cuscuta campestris Yunck.) were investigated under greenhouse conditions. Among these varieties, two susceptible and resistant varieties (Supra Urbana and Super Chef, respectively) were selected and catalase, guaiacol peroxidase, ascorbate peroxidase, total phenolic compound, proline, flavonoid and soluble sugars was evaluated at different times after infection (0, 24, 48, 72, 96, 120 and 240 Hours). The results showed that dodder infection increased the enzymes concentration (catalase, guaiacol peroxidase, ascorbate peroxidase) compared to the non- infection treatment. Also, the amount of these enzymes in resistant cultivar were higher than susceptible cultivar. Variety and sampling time affected on total phenol content, proline, flavonoids and soluble sugars. Total phenolic compound and flavonoid levels increased after attaching the dodder to the tomato and reached its highest level at 240 h after attachment. This results indicates the induction antioxidant defence system in tomato under dodder infection. The results of this study show that contamination of tomato with dodder induces the immune system in this plant. Given that it is not possible to perfect control of parasitic weeds without crop damage, it can be very useful to know the defence mechanisms by which cultivars resistant to parasitic plants stand.