Reactions of Six Spring and Winter Types of Canola Cultivars to Slerotinia sclerotiorum (Lib) de Bary, the Causal Agent of Sclerotinia Stem Rot Disease, at Seedling Stage in Greenhouse

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most important diseases of canola in Iran and other countries. It is more distributed in north part of Iran (Golestan and Mazandaran Provinces). The reactions of four spring and two winter types of canola cultivars Sarigol, Hayola, Quantum and RGS003 (spring type)and Okapi and Talaieh (winter type) to three isolates of S.sclerotiorum, SS1Go (isolated from RGS003, Araghi Mahalleh Research Station, Golestan Province), SS2Sari (isolated from Hayola, Gharakil Research Station, Mazandaran Province) and SS3Cal (isolated from Hayola, Calale, Golestan Province), were evaluated in greenhouse conditions. Two experiment, were carried out in randomized complete block design with three replications by either wounding or non-wounding inoculation methods.Each experiment was repeated three times. Reactions were recorded as the length of the lesions five days after inoculation. Analysis of variance was applied using a factorial design for each type of inoculation separately. There were significant (P < 0.01) differences in resistance to sclerotinia stem rot among cultivars. Isolates were different in virulence and SS1Go was more virulent than the other two isolates. Winter type cultivars Okapi and Talaieh, showed more tolerance to disease, and among spring type cultivars, Sarigol was more susceptible.Wounding inoculation time was effective on lesion development and disease improvement.