Mycelial Compatibility Groups and Pathogenicity of Isolates of Sclerotinia sclerotiorum (Lib.) De Bary, Causal Agent of Cabbage Head Rot in Urmia

Yousefdoost, Vahideh; Ghosta, Youbert

doi:10.22055/ppr.2015.11980

Mycelial Compatibility Groups and Pathogenicity of Isolates of Sclerotinia sclerotiorum (Lib.) De Bary, Causal Agent of Cabbage Head Rot in Urmia

Document Type : Research paper-Persian

Authors

assistant professor

10.22055/ppr.2015.11980

Abstract

In this study, 223 isolates of Sclerotinia sclerotiorum, the causal agent of cabbage head rot, were collected from different fields in Urmia. Identification of mycelial compatibility groups (MCGs) were done on Potato Dextrose Agar (PDA) culture media amended with McCormick's red food coloring. A total of 36 MCGs were identified. 23 MCGs (63.88%) consisted of one isolate each and the others more than one isolate. Aggressiveness of the isolates was done on detached cabbage leaves in laboratory conditions and lesion development were determined on treated leaves. All the tested isolates were pathogenic on cabbage leaves and developed disease symptoms, but the aggressiveness was varied greatly among the isolates. There was not any correlation between aggressiveness of the isolates, MCGs and isolation location. Isolates obtained from one field grouped in different MCGs, and there was difference in aggressiveness of isolates within and among MCGs. Results of this study showed that there was high level of mycelial incompatibility among the Sclerotinia sclerotiorum isolates obtaind from cabbage fields in Urmia. The high level of mycelial incomtibility indicates the genetic heterogenity in this fungus and should be noted in management strategies especially using resistant cultivars.

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