Spring-type oilseed Brassica napus L., commonly known as canola, has become the cornerstone of agricultural production in Western Canada, with the total acreage seeded increasing in each production year over the past two decades. However, the narrow genetic base of spring B. napus canola coupled with the ever-increasing acres planted have led to the emergence of clubroot disease, caused by Plasmodiophora brassicae, in the canola production areas. Brassica napus var. napobrassica, or rutabaga,

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... a biennial fodder-type Brassica species that has the potential to not only serve as a source of genetic diversity for B. napus, but also to provide strong resistance to P. brassicae pathotypes prevalent in the canola fields in Western Canada. An F 2 -derived population of Rutabaga-BF × A07-26NR and a three-way cross-derived population of (A07-45NR × Rutabaga-BF) × A07-26NR were evaluated for different agronomic and seed quality traits, including resistance to P. brassicae pathotypes prevalent in Western Canada. The three-way cross and F 2 -derived populations both produced families that exceeded the checks for agronomic and seed quality traits for both the 2013 and 2014 yield trial experiments. The three-way cross-derived population produced several families with stable, non-segregating resistance to P. brassicae pathotype 3, as well as newly emerging pathotypes found in northern Alberta. Genetic diversity analysis showed that both the three-way cross and F 2 -derived populations produced families of canola-quality B. napus plants with spring growth habit that were genetically similar to the parent Rutabaga-BF, indicating that rutabaga is a viable germplasm source for broadening the narrow genetic base of spring-type B. napus. iii Acknowledgments First and foremost, my sincere thanks to my supervisor Dr. Habibur Rahman for his persistence and resolve in helping me complete my program from start to finish. Forcing me to think and critically examine data from an academic and research perspective was an invaluable experience, and although I may not have recognized this at certain points during my research, I recognize and am grateful for his efforts and persistence as I complete my program. , as well as Victor Manoli and Kelly Dunfield with the Pathology group. Thank you for all your help, expertise and advice; it was invaluable throughout my research. This research would not have been possible without the help of Tim Darragh. For the suggestion of attempting an MSc., and going above and beyond aiding me in the process at the start of my program, words cannot express my debt to you. Also, my thanks to Dr. Alan Grombacher for his recommendation and advice throughout my program. My fellow grad students, during the longest days, it was good to know that I was not the only one under stress. Thanks for your advice, discussions and most importantly, friendship. To my parents, Lyndon and Dallas Flad, and my brother Devon, thanks for the support and encouragement throughout my program.