Transgenic Herbicide Tolerant Canola—The Canadian Experience

Canola is a Canadian development, having been derived through conventional plant breeding of rapeseed (Brassica napus L. and B. rapa L.). The acceptance of canola in the marketplace has been assisted by the proliferation of new cultivars registered under the mandate of the Canadian Food Inspection Agency (CFIA). New cultivars, whether conventional or transgenic, are evaluated and approved for registration by a national committee known as the Western Canada Canola/Rapeseed Recommending Committee (WCC/RRC). Regulatory approval for transgenics is granted by the CFIA and Health Canada, who oversee the confined and unconfined release of these products into the environment. Transgenic canola cultivars, Roundup Ready {glyphosate [N-(phosphonomethyl)glycine] tolerant}, and Liberty Link {glufosinate [2-amino-4-(hydroxymethylphosphinyl)butanoic acid] tolerant} were first registered in Canada in 1995, while Navigator [bromoxynil (3,5-Dibromo-4-hydroxybenzonitrile) tolerant] cultivars appeared later. Herbicide tolerant (HT) transgenics have enjoyed increased market share since their development, and now occupy ≈55% of the canola acreage in western Canada. The popularity of these cultivars appears to arise more from agronomic rather than economic advantages. Tolerance tests have failed to show any significant effect of the herbicides on the cultivars.