Novel food information: Imidazolinone tolerant ClearfieldTM wheat (teal 11a)

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Health Canada has notified BASF Canada Inc. that it has no objection to the food use of grain from the Triticum aestivum line teal 11a developed through mutation breeding, which is tolerant to imidazolinone herbicides. The Department conducted a comprehensive assessment of this wheat according to its Guidelines for the Safety Assessment of Novel Foods (September 1994). These Guidelines are based upon internationally accepted principles for establishing the safety of novel foods.

The following provides a summary of the BASF Canada Inc. notification to Health Canada and the results of the safety assessment. This summary contains no confidential business information.


BASF Canada has developed wheat line teal 11a, which is tolerant to imidazolinone herbicides. It joins a family of imidazolinone tolerant crops produced in a similar way and previously reviewed by Health Canada, namely imidazolinone tolerant corn, canola, rice, and wheat.

Development and production of the modified plant

Wheat is grown widely throughout North America as a food and feed crop. The principal use of wheat grain is the production of flour which, depending on the specific type of wheat, is used in many baked goods and bread and pasta.

The petitioner has provided information describing the methods used to develop wheat line teal 11a and data that characterizes the genetic change which confers tolerance to imidazolinone herbicides. Seed from the hard red spring wheat cultivar CDC teal was mutagenized using ethyl methanesulfonate (EMS). This mutagen is commonly used in plant breeding and generates nucleic acid substitution mutations.

The mutation responsible for imidazolinone tolerance is due to a point mutation of a single nucleotide in one of three AHAS genes found in teal 11a (Triticum aestivum has three genomes). The petitioner has identified the mutation in the AHAS gene which confers herbicide tolerance by sequencing and shown it to be a single base pair change that codes for a single amino acid change in the AHAS protein. As with the previously approved imidazolinone tolerant wheats, rice, corn and canola, the single amino acid change alters the binding site for the herbicide on the AHAS enzyme while having no effect on the normal functioning of the enzyme. Because teal 11a is intended to be used as breeding material to introduce the ClearfieldTM trait into other wheat, and not as a stand-alone variety, it was not backcrossed to CDC teal. Instead, it was self-fertilized for seed multiplication.

Product information

A mutation in the AHAS enzyme in wheat could affect the biosynthesis of the essential amino acids isoleucine, leucine, and valine. The amino acid composition of ClearfieldTM wheat line teal 11a was compared to commercial cultivars, confirming that the AHAS activity of the imidazolinone-tolerant wheat was not affected by the mutation.

Dietary exposure

Imidazolinone tolerant ClearfieldTM wheat line teal 11a is expected to be used in the same applications as other wheat varieties by the food industry.


The nutrient data pertaining to ClearfieldTM wheat variety teal 11a comprised three data sets which were obtained through 3 different field trials. All three trials included the analysis of wheat grain samples from the teal 11a variety and from its parent, Gunner. In one of the trials, wheat grain samples were also obtained from the commercial variety CDC teal. The wheat grain samples were analyzed for proximates (moisture, crude fat, protein, crude fibre), 18 amino acids, minerals (iron, magnesium, phosphorous, and zinc), vitamins (niacin, pantothenic acid, thiamin, and vitamin B6,) 33 fatty acids and 2 antinutrients (phytic acid and trypsin inhibitor). There were significant differences found between the teal 11a and Gunner varieties in the levels of two fatty acids, oleic and palmitic acids, however, these differences are not biologically significant in wheat grain since the fat content of the grain is less than 2% and these fatty acids make up only a portion of the fat. If the wheat germ oil were extracted and used as an ingredient, the differences would still not be considered biologically significant since the levels in the ClearfieldTM wheat fall within the range of variation for these fatty acids as shown by the control varieties in the study and data reported in the scientific literature.

Based on the nutrient data provided in this submission, it is recommended that imidazolinone tolerant wheat variety teal 11a be permitted for food use in Canada.

Since there would not be expected to be any change to the gluten content of this variety of wheat, there is no new or additional concern for individuals with celiac disease.


The weight of evidence suggests that the mutant AHAS from teal 11a wheat is unlikely to be a toxin or allergen under normal conditions of consumption. This conclusion is based on the observations that the protein is present in very low amounts in the edible part of the wheat, its activity is heat-labile and would be destroyed during normal food preparation processes, and the protein is as sensitive to degradation in the human gastrointestinal tract by trypsin as the native protein. Consequently, systemic exposure to the intact AHAS was considered negligible. Further, the modified AHAS protein is not homologous to known allergens and did not differ from native AHAS in its similarity to known food allergens. In addition, the teal 11a wheat does not express any new major proteins or altered amounts of other proteins, which includes endogenous wheat allergens. Additional unintended effects of genetic modification affecting the chemical safety of the product, such as altered levels of endogenous or environmental toxins in teal 11a as compared with the teal wild- type wheat was not considered as issue for this product.


Health Canada's review of the information presented in support of the food use of imidazolinone tolerant wheat line teal 11a concluded that the food use of grain from this wheat line does not raise concerns related to safety. Health Canada is of the opinion that grain from wheat line teal 11a is as safe and nutritious as grain from current commercial wheat varieties.

Health Canada's opinion deals only with the food use of imidazolinone tolerant wheat variety teal 11a. Issues related to its use as animal feed have been addressed separately through existing regulatory processes in the Canadian Food Inspection Agency.

This Novel Food Information document has been prepared to summarize the opinion regarding the subject product provided by the Food Directorate, Health Products and Food Branch, Health Canada. This opinion is based upon the comprehensive review of information submitted by the petitioner according to the Guidelines for the Safety Assessment of Novel Foods (September 1994).

For further information, please contact:

Novel Foods Section
Food Directorate
Health Products and Food Branch
Health Canada, PL2204A1
251 Frederick Banting Driveway
Ottawa, Ontario K1A 0K9

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