New clubroot pathotypes and second generation resistance

Key Result

This project is currently in progress, but it is focused on determining the nature of the interaction between the clubroot pathogen and 2nd generation CR canola, facilitating knowledge-based breeding and the strategic deployment of CR canola cultivars, in order to benefit growers and the canola industry as a whole.

Project Summary


Clubroot, caused by Plasmodiophora brassicae, is one of the most important disease issues facing Canadian canola growers. An integral part of the multi-pronged approach to clubroot management in canola, genetic resistance represents the most efficient and effective tool of the management efforts. In recent years, as resistance has come under pressure from the emergence of ‘new’ pathotypes of the clubroot pathogen, there has been a concerted effort to develop canola with novel resistance traits.

This effort has resulted in the recent release of multiple cultivars advertised as having “2nd generation” resistance. Unfortunately, the identification of 2nd generation clubroot resistant (CR) canola with symptoms of clubroot disease indicates that this resistance may also be at risk. Since the nature of 2nd generation resistance is not in the public domain and may differ across varieties, it is important to gain an understanding of the virulence of the clubroot pathogen on these cultivars in order to develop appropriate mitigation measures. Unless a clear understanding of the virulence of P. brassicae on 2nd generation resistance can be obtained, there is a great risk of jeopardizing this resistance as well.


This project will:

(1) evaluate the infectivity of the most important P. brassicae pathotypes on a suite of canola cultivars with 2nd generation resistance

(2) determine the pathotype composition on 2nd generation CR canola recovered from commercial fields

(3) assess the cross-infectivity of these pathotypes across 2nd generation CR canola cultivars.