Herbicide tolerance

CFIA (Canadian Food Inspection Agency) (1995). Decision Document DD95-02 Determination of Environmental Safety of Monsanto Canada Inc. s Roundup Herbicide-tolerant Brassica napus Canola Line GT73, Canadian Food Inspection Agency, Ottawa,... 

Lawton, M. (2003). Management of Herbicide Tolerant Crops and Future Research, Canadian Food Inspection Agency, Plant Products Directorate, Plant Biosafety Office Technical Workshop on the Management of Herbicide Tolerant (HT) Crops Report. www.inspection.gc.ca/english/plaveg/bio/consult/herbtolrepe.shtml 7. Accessed June... 

WERCK-REICHHART, D., HEHN, A., DIDIERJEAN, L Cytochromes P450 for engineering herbicide tolerance, Trends Plant. Sci., 2000,3, 116-123. 

Genetically modified crops, 13 533-534 herbicide-tolerant, 13 534-535 Genetic complementation, 12 503 Genetic differences, influence on toxicity, 25 212... 

A more recent factor affecting weed management has been the introduction of crops genetically altered for tolerance or resistance to herbicides. The first herbicide-tolerant field com (IMI hybrid corn) was developed as a way to reduce the effects of carryover from imidazolinone and sulfonylurea herbicides applied to soybean in a corn-soybean rotation. These hybrids also soon found use in areas where triazine use was restricted. 

Chloro- -triazines have been shown to be metabolized in plants by one of four competing processes hydrolytic dehalogenation, oxidative /V-dcalkylation, nucleophilic displacement of the chlorine atom with glutathione, and ami-nation or deamination reactions. Much of the early research focused on the first three processes and attempted to determine the relative importance of each process to herbicide tolerance. The relevant research undertaken between 1961 and 1973 will be discussed. 

Hilton, H.W. (1957). Herbicide tolerant strains of weeds. Hawaiian Sugar Planters Association. Annual Report, p. 69. 

Triazine herbicides provide cost-effective, broad-spectrum weed control and are key tools in conservation tillage. Although the chemical alternatives to the triazines are more costly and generally less efficacious, they are considerably more reliable as weed control methods and more compatible with current farming operations than available nonchemical weed control methods. Even as more com acreage shifts to herbicide-tolerant com, the need remains for residual herbicides such as the triazines to manage resistant weeds and to avoid the need for multiple tillage passes for weed control. 

In general there are two categories for testing for the presence of food derived from modem biotechnology. Testing for the phenotype (herbicide tolerance or proteins) includes ... 

Traits Herbicide tolerance Most herbicide tolerant and insect protected plants All... 

Soybean Herbicide tolerance Leaf Agrobacterium tumefaciens CP4 EPSPS (44)... 

Brandao et al. also applied the bottom-up approach to compare seed-protein profiles of herbicide-tolerant soybean and its near-isogenic line (60). Some 2-DGE parameters such as the loaded mass of the proteins, the pH separation range, and manual/automatic image editing were optimized prior to the evaluation (Figure 2). Of the 10 proteins with at least 90% variation found to be differentially expressed between the GM soybean and its counterpart, 8 proteins were successfully identified by MALDI coupled to a quadrupole (Q)-TOF MS. 

She is referring to the GE crops that are engineered with a bacterial protein that makes them tolerant to the herbicide glyphosate. This is the main component of Monsanto s Roundup, (box 5.2). Conventional farmers like these GE crops because they can spray the herbicide on the weeds. The weeds die, and even if the herbicide drifts onto the GE crop, the crop will survive. Because no hoeing or cultivating is needed, herbicide-tolerant GE crops are now widely grown. 

First commercialized in 1996, today, Bt crops are the most commonly grown transgenic crops in the world. In 2004, an estimated 200 million acres of GE crops with Bt and/or herbicide tolerance were cultivated in seventeen countries worldwide, a 20% increase over 2003. U.S. acreage accounts for 59% of this amount followed by Argentina (20%), Canada and Brazil (6% each), and China (5%) (Fernandez-Cornejo and Caswell 2006). 

One model for coexistence between GE and non-GE crops is the program established for publicly owned land in Boulder County, Colorado (Byrne and Fromherz, 2003). The county leases about 4,000 acres of cropland to farmers, some of whom have chosen to grown insect resistant or herbicide tolerant GE corn. An advisory committee of farmers, scientists, and concerned citizens developed a set of protocols to minimize cross-pollination to nearby non-GE corn fields. The protocols include grower notification to the county of their planting intentions, communication among neighboring farmers to work out an acceptable coexistence plan, and establishment of a 150-foot buffer zone between fields to minimize cross-pollination. 

Herbicide-tolerant (HT) crop A crop able to survive the application of one or more synthetic chemical herbicides, many of which are toxic to both crops and weeds. Includes those conventionally bred and those genetically engineered to contain genes (or mutated genes) that make them insensitive to or able to detoxify herbicides. 

Devos, Y. Reheul, D. De Schrijver, A. Cors, F. and W. Moens (2004) Management of herbicide-tolerant oilseed rape in Europe a case study on minimizing vertical gene flow.- Environ. Biosafety Res.3, 135-148. 

There is much controversy, at least in Europe, concerning genetic modification of plants. The three major crops affected so far are maize, soyabean and rapeseed. All of these, in addition to their other uses, are sources of oil. The reasons for modification in all these cases are related to herbicide tolerance and resistance to insects. For the varieties generally available at present, there is no known difference from non-modified strains with respect to fatty acid composition, oil yield, tocopherol level, or the level of any other minor oil constituent. 

Herbicide tolerance in food crop USDA Safe to grow... 

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