Herbicide Resistant Canola

Friesen, L.F., Nelson, A.G. and Van Acker, R.C. (2003). Evidence of contamination of pedigreed canola (Brassica napus) seedlots in western Canada with genetically engineered herbicide resistance traits . Agron J, 95, 1342-1347. 

Legere, A. (2005). Risks and consequences of gene flow from herbicide-resistant crops canola (Brassica napus L) as a case study , Pest Manag Sci., 61, 292-300. 

Rieger, M.A., Lamond, M., Preston, C., Powles, S.B. and Roush, R.T. (2002). Pollen-mediated movement of herbicide resistance between commercial canola fields, Science, 296, 2386-2388. 

Brimner, T.A., Gallivan, G.J. and Stephenson, G.R. (2005) Influence of herbicide-resistant canola on the environmental impact of weed management. Pestic Manage Sci, 61, 47—... 

Upadhyay, B.M., E.G. Smith, G.W. Clayton, K.N. Harker, and R.E. Blackshaw (2006). Economics of integrated weed management in herbicide-resistant canola. Weed Sci., 54 138-147. 

New introductions, including herbicide-resistant canola, virus-resistant papaya, and other food crops, have been accepted. Soybean producing an oil containing the co-3 fatty acid stearidonate has been developed for the nutraceutical and fish farm feed market [3]. Interestingly, the earliest genetically engineered oilseed crop was... 

In 2005, GM crops were cultivated in 21 countries with 71% of those acres being accounted for by herbicide resistant traits in soybean, corn, canola, and cotton. This percentage increases to 82% if one includes herbicide resistance trait acres that are stacked with other biotechnology traits. Globally, GM herbicide resistant soybean, cotton, canola, and corn were grown on 134.4 (60%), 12.1 (14%), 11.4 (18%), and 24.5 (7%) million acres, respectively. (Fig. 6.1.1) [1]. 

This section includes data for herbicide resistant crops generated by both selection and biotechnology processes. The first commercially available herbicide resistant crop in the United States was imidazolinone resistant corn introduced in 1992. This was followed by glyphosate resistant soybean and canola in 1996. 

Canada cultivates 90% of the canola acres in North America and is the focus of this survey. The three primary commercial herbicide resistant traits in canola are glyphosate resistance (Roundup Ready , RR), glufosinate resistance (Liberty Link , LL), and imidazolinone resistance (Clearfield , CF). There are two other herbicide resistant traits that are used on a relatively small number of acres and these are bromoxynil resistance (BXN ) and triazine tolerance (TT). In 2004, herbicide resistant traits were grown on over 90% of the 12-13 million total canola acres in Canada (Fig. 6.1.5) [7, 8]. 

Fig. 6.1.5. Percentage of total acres of herbicide resistant canola by trait.

As mentioned above, there is a key exception to the rule that sulfonylurea herbicide selectivity is based on metabolic inactivation. This exception is the case of plants which, through mutation, selection, or genetic engineering methods, have acquired a gene coding for a herbicide-resistant form of the ALS enzyme. Crop species which have been selected or engineered for broad resistance to sulfonylureas by this mechanism include soybeans (28), tobacco (17, Ig), and canola (22), with similar efforts proceeding in other crops (40 ... 

The outcrossing of GE crop traits to native germplasm has occurred in some cases and introduction of herbicide resistance to closely related species that are invasive weeds is a major concern (Warwick et al 2009). Engineered crops can be planted with a buffer zone of nonmodified crops for containment of any outcrossing to native germplasm or related weeds and to reduce the development of insect resistance to biopesticides introduced in the GE crop. Buffer zones are also used for non-GE crop plants such as canola and rapeseed, where outcrossing can occur over some distance resulting in seed with undesirable composition. 

Jhala, A.J., Raatz, L., Dexter, J.E., Hall, L.M., 2010. Adventitious presence volunteer flax (Unum usitatissimum L.) in herbicide resistant canola (Brassica napus L.). Weed Technol. 24,244-252. 

Bettini, P, S. McNally, M. Sevignac, H. Darmency, J. Gasquez, and M. Dron (1987). Atrazine resistance in Chenopodium album Low and high levels of resistance to the herbicide are related to the same chloroplast psb A gene mutation. Plant Physiol., 84 1442-1446. Beversdorf, W.D., B.J. Hume, and M.J. Donelly-Vanderloo (1988). Agronomic performance of triazine-resistant and susceptible reciprocal spring canola hybrids. Crop Sci., 22 932-934. 

The cleaning of all tillage equipment prior to leaving the site will limit SMGF. The choice of crop to follow transgenic safflower will depend on thresholds for AP of PMP in commodity crops. In a cereal or some canola systems (glyphosate and imidazolinone resistant), field operations and herbicides limit safflower volunteer survival and fecnndity, but they are not eliminated. 

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