Evaluation of Resistance of Canola Cultivars Against Sclerotinia sclerotiorum, the Causal Agent of White Stem Rot, Using Cotyledon Test

Sclerotinia stem rot (white stem rot), an important fungal disease, which is caused by Sclerotinia sclerotiorum, is one of the serious diseases of various plants such as canola. Use of resistant cultivars is an effective method to control the disease. A greenhouse experiment based on cotyledon inoculation using mycelial suspension of two different isolates of S. sclerotiorum was conducted to evaluate 12 canola cultivars (including seven spring type and five winter type) against the pathogen. The results demonstrated that response to S. sclerotiorum was significantly different among cultivars (P = 0.05). Interaction between isolates and cultivars was also significant (P = 0.05). Hyola 401 with the highest and Zarfam with the lowest infections, were the most susceptible and the most resistant cultivars, respectively. The results of this experiment showed that cotyledon test is a reliable and rapid method for screening canola cultivars against white stem rot fungus.