1:00 pm - 2:00 pm
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Yingyi Liu. This seminar is open to the general public to attend.
Meeting ID: 989 3860 4584 | Passcode: 937658
Thesis Topic: Use of Turnip (Brassica rapa var. rapifera) and Rutabaga (B. napus var. napobrassica) for the Improvement of Clubroot Resistance in Spring B. napus Canola
MSc with Drs. Habibur Rahman and Gavin Chen.
Clubroot disease, caused by Plasmodiophora brassicae, is one of the most serious threats to spring Brassica napus canola production in Canada. Growing of clubroot-resistant cultivars is the key to control this disease, but the spring B. napus canola carries a narrow genetic base cannot provide strong resistance to multiple newly evolved pathotypes. In this study, two advanced-generation breeding populations of spring B. napus canola, including a BC1F8 population derived from spring B. napus canola × B. rapa subsp. rapifera European fodder turnip accession ECD 01 interspecific cross and a doubled haloid (DH) population developed from spring B. napus canola × B. napus var. napobrassica rutabaga cv. Polycross cross, were accessed for resistance to different pathotypes of P. brassicae. The clubroot resistance tests results confirmed resistance to P. brassicae pathotypes 2B, 3A, 5x (L-G1) and 3H in the turnip accession ECD 01 and resistance to pathotypes 2B, 3A, 5x (L-G1), 3H and 3D in the rutabaga cv. Polycross. Genetic linkage analysis using the DH population identified a locus qCRa_A03 on chromosome A03 associated with resistance to P. brassicae pathotypes 2B, 3A, 5x (L-G1), 3H and 3D, a locus qCRb_A03 on A03 linked to resistance to pathotypes 2B, 3H and 3D, a locus qCRc_A03 on A03 carrying resistance to pathotypes 3H and 3D, a locus qCRa_A08 on A08 co-segregating with resistance to pathotypes 2B, 5x (L-G1), 3H and 3D, and a locus qCRb_A08 on A08 conferring resistance to pathotype 3A. The loci qCRa_A03 and qCRb_A03 were located at about 16 Mb of A03, while the locus qCRd_A03 was positioned at about 25 Mb region of A03. The loci qCRa_A08 and qCRb_A08 were mapped to the region 11.3-12.7 Mb of A08. Thus, results from this thesis research indicated that the excellent resistance in the turnip accession ECD 01 and rutabaga cv. Polycross can be used to broaden the genetic base of spring B. napus canola for resistance to multiple P. brassicae pathotypes such as 2B, 3A, 5x (L-G1), 3H and 3D. Clubroot resistance on A03 and A08 of the rutabaga cv. Polycross can be used in the breeding of clubroot-resistant B. napus canola cultivars through marker-assisted selection (MAS) as well as fine-mapping of the QTL regions and map-based cloning of the clubroot resistance genes.