Screening ofBrassicagermplasm for resistance toPlasmodiophora brassicaepathotypes prevalent in Canada for broadening diversity in clubroot resistance

Abstract

Hasan, M. J., Strelkov, S. E., Howard, R. J. and Rahman, H. 2012. Screening of Brassica germplasm for resistance to Plasmodiophora brassicae pathotypes prevalent in Canada for broadening diversity in clubroot resistance. Can. J. Plant Sci. 92: 501–515. Clubroot disease of crucifers, caused by Plasmodiophora brassicae, poses a threat to the Canadian canola industry, and the development of resistant cultivars is urgently needed. Germplasm resistant to local pathotype(s) is the prime requirement for breeding clubroot-resistant cultivars. The objective of this study was to identify Brassica germplasm possessing resistance to P. brassicae pathotypes prevalent in Alberta. Pathotype-specific resistance was identified in the diploid species Brassica rapa (AA) and B. oleracea (CC), and in the amphidiploid B. napus (AACC). Among B. rapa genotypes, turnip was the most resistant, followed by winter type and spring type oilseed rape. The rutabaga group of B. napus, on the other hand, was homogeneous for resistance to Canadian P. brassicae pathotypes. The diploid species B. nigra (BB) also showed pathotype-specific resistance. However, the two amphidiploids carrying the B. nigra genome, B. juncea (AABB) and B. carinata (BBCC) were completely susceptible to clubroot.

Genotyping-by-sequencing reveals three QTL for clubroot resistance to six pathotypes of Plasmodiophora brassicae in Brassica rapa

“…brassicae have been identified in the canola progenitor species B . rapa 11, 12 . This species could be used to broaden the genetic base of clubroot resistance in canola.…”

Mapping of the clubroot disease resistance in spring Brassica napus canola introgressed from European winter canola cv. ‘Mendel’

“…Among the A and C genome Brassica species, some genotypes or varieties of B. rapa (2n = 20, AA) often possess clubroot resistance (CR) and also exhibit higher levels of resistance than B. oleracea (2n = 18, CC) (Crisp et al 1989, Hasan et al 2012; for reviews, see Piao et al 2009;Rahman et al 2014). On the other hand, Brassica species that contain the B genome, viz.…”

“…On the other hand, Brassica species that contain the B genome, viz. diploid species B. nigra (2n = 16, BB) often carry resistance (Hasan et al 2012), however, the amphidiploid species B. juncea (2n = 36, AABB) and B. carinata (2n = 34, BBCC) are mostly susceptible to clubroot disease (Crisp et al 1989;Diederichsen et al 2009;Hasan et al 2012). In B. rapa resistance is found more commonly in European fodder turnip (B. rapa spp.…”

Genetics and molecular mapping of resistance toPlasmodiophora brassicaepathotypes 2, 3, 5, 6, and 8 in rutabaga (Brassica napusvar.napobrassica)

“…In case of B. napus, some of the swede or rutabaga (B. napus var. napobrassica) genotypes reported to possess resistance to different P. brassicae pathotypes (Ayers and Lelacheur 1972;Buczacki et al 1975;Crute et al 1983; Gustafsson and Falt 1986) including the pathotypes prevalent in Canada (Hasan et al 2012). Ayers and Lelacheur (1972) reported that resistance to P. brassicae races 2 and 3 in rutabaga cv.…”

“…Wilhelmsburger carries one gene for resistance to race 3 and two genes for resistance to race 2. Hasan et al (2012) reported that the rutabaga cultivars Brookfield and Polycross carry resistance to pathotypes 2, 3, 5, 6 and 8 which are threats to the Canadian canola crop. The objectives of this research was to study the genetic basis of resistance in Brookfield, and map the resistance genes through construction of a linkage map and identify molecular markers for use in marker assisted selection.…”