Genetic detection of clubroot resistance loci in a new population of Brassica rapa

• DOI: 10.1007/s13580-014-0079-5
• Publication Date: 2015-01-14T03:46:39Z
• Authors: Wenxing Pang; Shan Liang; Xiaonan Li; Pengpeng Li; Sha Yu; Yong Pyo Lim; Zhongyun Piao
• Keywords: Clubroot; Brassica rapa; Inbred strain; Genetic Analysis

Clubroot is one of the most serious diseases affecting Brassica crop production worldwide. In order to identify the location of clubroot resistance genes in Chinese cabbage, we constructed a linkage map for an F2 population derived from a cross between a resistant turnip inbred line, 'Siloga' (B. rapa ssp. rapifera), and a susceptible Chinese cabbage inbred line, 'BJN3' (B. rapa ssp. pekinensis). The newly developed genetic map included 207 markers and covered 1151.7 cM. In combination with clubroot resistance tests from the field, the data allowed us to identify three quantitative trait loci of clubroot resistance, using a composite interval mapping method. Clubroot resistance genes QS_B1.1, QS_B3.1, and QS_B8.1 were located on chromosomes A1, A3, and A8, respectively, of B. rapa. Their contribution rates were 8.18%, 70.55%, and 7.28%, respectively. QS_B1.1 was a novel locus of clubroot resistance, independent of any published clubroot-resistance loci. QS_B3.1 was first detected in 'Siloga,' mapped to the previous CRb and CRa region, whereas QS_B8.1 was closely linked to Crr1b. Epistatic interactions with additive effects were detected between QS_B3.1 and QS_B8.1.