Genetically engineered oilseed rape in Canada
Canada was the first country to approve the commercial cultivation of genetically engineered herbicide tolerant oilseed rape. Currently herbicide tolerant oilseed rape is grown on eight million hectares in Canada. The spread of genetically engineered oilseed rape became public when a study claimed that nearly all of the conventional Canadian seed supply of oilseed rape contained transgenes. Several other studies published later on found that throughout the main cultivation areas feral populations had developed at the edges of fields and along roadsides. In 2008, a study showed that 88 percent of feral oilseed rape populations examined in the province of Manitoba contained glyphosate tolerant plants. 81 percent were glufosinate tolerant. About 50 percent of the plants were tolerant to both herbicides. According to research, populations are able to sustain themselves due to large-scale cultivation that leads to gene flow from transgenic oilseed rape. In 2010, scientists found that between 93 and 100 percent of feral oilseed rape plants along field edges or roadsides in Manitoba tested positive for transgenic constructs. According to another publication, feral genetically engineered oilseed rape is also present in Québec. Additionally, all feral populations that were tested contained hybrids with Brassica rapa. Persistence of such hybrid populations over time was affirmed. A long-term survey showed that feral hybrid populations of B. napus x B. rapa had decreased fitness, but nonetheless persisted over six consecutive years.