Effect of seeding date on winter canola (Brassica napus L.) yield and oil quality in southern Ontario

Winter canola or winter oilseed rape (Brassica napus L.) is not commonly grown in Canada. While winter oilseed rape is the dominant growth form in Europe, Canadian canola production is dominated by spring types in western Canada. Research conducted in the 1980s indicated that the environmental conditions in southern Ontario are well suited to the production of winter canola. Since then, however, interest in the crop has ebbed, and little to no research has been conducted on the agronomic issues that potentially limit its adoption in the province. The objective of this research was to identify an optimal seeding date for winter canola in southern Ontario. Three winter canola hybrids were evaluated across five seeding dates, ranging from early September to late October. The results established the first two weeks of September as the optimal seeding period for winter canola in southern Ontario. Seeding winter canola during this period, such that greater than 600 growing degree days could be accumulated before the first fall frost, not only reduced winterkill to approximately 20%, but also maximized yield potential and ensured optimal oil quality. Winter canola showed great potential for production in southern Ontario, and its addition to current crop rotations would diversify and enhance crop production practices in this portion of the province.