Variation in Plasmodiophora brassicae and resistance to clubroot disease in brassicas and allied crops: a critical review

Variation in Plasmodiophora brassicae and resistance to clubroot disease in brassicas and allied crops: a critical review

1980

A:PS

Plasmodiophora brassicae Wor., the causal agent of clubroot of crucifers, exhibits considerable variation in pathogenicity and pathotypes can easily be identified. Various systems of identifying and naming such pathotypes have been used, but recently a uniform system of coding field collections has been developed using one set of host genotypes referred to as the European Clubroot Differential (ECD) set. The theoretical capabilities of the ECD set are explored in this review together with the constraints on describing and quantifying pathogenic variatio in P. brassicae. The potential sources of such variation are also considered. Differential resistance to P. brassicae has been incorporated into cultivars of Brassica napus L. and B. campestris L. This resistance is governed by a few dominant genes and, when effective, is expressed at a high level. In contrast, there have been few attempts to breed for resistance in B. oleracea, in which the available resistance appears to be under recessive polygenic control, is incomplete in effect, and yet may also be differential. High levels of resistance are apparently present in lines of some Raphanus species. Limited success in transferring genes for resistance has been achieved by interspecific and intergeneric hybridization although recovery of crop type is difficult. Breeding techniques and strategies which may be appropriate to the control of P. brassicae by the development of resistant crop cultivars are discussed together with the areas in which there is need for further research. [AS]

v.50(2):91-104, PLANT BREEDING ABSTRACTS

Research > Published Articles