Transferring clubroot resistance from Chinese cabbage (Brassica rapa) to canola (B. napus)

• Published in: Canadian journal of plant pathology 2016-01, Vol.38 (1), p.82-90
• Main Authors: Hirani, Arvind H., Gao, Feng, Liu, Jun, Fu, Guohua, Wu, Chunren, Yuan, Yuxiang, Li, Wei, Hou, Jinna, Duncan, Robert, Li, Genyi
• Format: Article
• Language: English
• Subjects: canola; Chinese cabbage; chou chinois; clubroot resistance; de canola; de la résistance de la hernie; hybridation interspécifique; interspecific hybridization; marker-assisted selection; sélection assistée par marqueurs
• ISSN: 1715-2992; 0706-0661; 1715-2992
• DOI: 10.1080/07060661.2016.1141799

Clubroot, caused by Plasmodiophora brassicae , is one of the most important diseases of Brassica species worldwide, including vegetable and oilseed crops. A dominant clubroot resistance gene from B. rapa (Chinese cabbage) was previously fine mapped and molecular markers were developed in Chinese cabbage that could be used for marker-assisted selection (MAS) in other Brassica crops. To transfer this clubroot resistance gene to B. napus (canola), an interspecific hybridization was made between B. napus (canola) and B. rapa (Chinese cabbage). Subsequently, the F ₁ was backcrossed to the canola recurrent parent for three generations to produce BC ₁, BC ₂ and BC ₃ progenies. Using these populations, simple sequence repeat (SSR) markers flanking the clubroot resistance gene were used to perform MAS in canola. These molecular markers were then evaluated in 13 different canola and rapeseed quality genotypes in B. napus and B. rapa . These markers exhibited high reliability in identifying clubroot resistance in this diverse set of Brassica genotypes. Clubroot resistance also co-segregated with the SSR markers flanking the clubroot resistance gene in the BC ₃ and BC ₃S ₁. The segregation ratio of resistant and susceptible individuals in the BC ₃ supported the expected 1:1 ratio for the segregation of a single Mendelian gene. BC ₃S ₁ families with homozygous clubroot resistance were developed during this process, and should be valuable sources of clubroot resistance in B. napus breeding activities.