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International Clubroot Working Group (ICWG)

The International Clubroot Working Group (ICWG) was founded in the early 1970s with the twin aims of providing a means for the informal exchange of information between researchers and developing an agreed series of differential genotypes which could be accepted internationally. Founding scientists were: Hille Toxopeus (The Netherlands), Peter Mattusch (Germany) and Geoffrey R Dixon (United Kingdom). During a meeting of Eucarpia held at what is now the John Hutton Institute at Invergowrie, Dundee (previously the Scottish Crop Research Institute, SCRI, and at the time Scottish Horticultural Research Intitute, SHRI) with Paul Williams (United States) contributing the European Clubroot Differential (ECD) Series was adopted. Initially seed of the 15 differentials was conserved and distributed by Hille Toxopeus from his Institute (SVP de Haaf, Wageningen). This role was later taken over by the Gene Bank at Wellesbourne, Warwickshire, UK, from where seed is currently still available.

The founding group also agreed to publish a Clubroot Newsletter which ran for about ten years. It contained a continuing record of tests made worldwide using the ECD series. This activity has in later years been adopted by the Cruciferae Newsletter which is still made available from INRA at Rennes, France. 

Research interest in both the causal organism Plasmodiphora brassicae and Clubroot disease has waxed and waned over the ensuing time. There would between 50 to 100 scientists actively interested internationally at any one time. The disease was seen as one of primary importance to horticultural brassica crops which despite its potential for devastating valuable crops grown intensively did not command the funding resources available for broad acre crops. Nevertheless, it has been possible over the years to maintain the founding objectives of providing means of communication and the availability of the ECD series. Meetings of interested scientists continued normally linked with larger events. Particularly helpful in this respect have been linkages with the Brassica Symposia and Crucifer Genetics Co-operative meetings and Congresses of the International Society for Plant Pathology. This has meant that at about two-yearly intervals active clubrooters (a term coined by Peter Mattusch) have gathered and discussed their findings.

Since about 2000 the pathogen and the disease which it incites has gained much increased importance by an aggressive advance into brassica oil seed crops. Clubroot disease had been recognised in Europe particularly as causing losses in oil seeds from about the mid 1980s. This stimulated private breeding companies to commence programmes aimed at developing resistant cultivars. But public funding for basic studies remained very limited. The invasion of crucially important oil seed crops in Canada and China by P. brassicae has stimulated much increased research effort and the availability of increased funding. The Canadian epidemic in particular has resulted in a substantial flow of important basic and applied research information. This has also meant that meetings of clubrooters are happening more regularly and in some instances as stand-alone events.

This website is another result of the increased research activity associated with rising recognition of the biological, agricultural, economic and social importance of clubroot disease and its causal microbe, P. brassicae. It offers much increased opportunities for clubrooters communications please make sure that you use it.

Professor Geoffrey R Dixon
Chairman Emeritus
12th January 2015