| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
a Dep. of Agricultural Food and Nutritional Sci., Univ. of Alberta, Edmonton, AB, Canada T6G 2P5
b AAFC-Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, Canada, S7N0X2
c Svalof Weibull Ltd, 2-411 Downey Rd, Saskatoon, SK, Canada S7N 4L8
d Monsanto Canada Inc., Suite 206-111 Research Dr., Saskatoon, SK, Canada S7N 3R2
* Corresponding author (gary.stringam{at}ualberta.ca).
 |
ABSTRACT |
|---|
 TOP ABSTRACT REFERENCES |
|---|
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.
Abbreviations: CFIA, Canadian Food Inspection Agency • HT, herbicide tolerant • WCC/RRC, Western Canada Canola/Rapeseed Recommending Committee
CANOLA ORIGINATED IN Canada through genetic modification of rapeseed by conventional plant breeding, and emerged in the 1970s as a viable oilseed, equipped with the appropriate genetics to transform the oil and meal from unacceptable to highly sought after products for both human and animal consumption (Shahidi, 1990). Since the 1970s, canola has enjoyed remarkable acceptance among consumers, largely because of its unique fatty acid profile. Nutritionists consider canola's fatty acid profile to be the most desirable of all available vegetable oil profiles.
The development of canola has been followed by intensive plant breeding efforts resulting in large numbers of new cultivars. In Canada, these cultivars are registered based on a merit system administered by the federal CFIA. A national expert committee, WCC/RRC, consisting of producers, seed and processing industry personnel, and researchers (including those with quality, pathology, and breeding expertise) evaluates each cultivar. Guidelines for cultivar acceptance have been established along with a series of check cultivars. A cultivar is automatically approved for registration by the Committee if certain minimum standards are met. A cultivar is not required to be superior to the checks, but usually would not be accepted in the marketplace unless it was at least equal in performance to the checks. Normally, 3 yr of data are required (first year private data, and 2 yr of public co-op data) to obtain registration approval. Canola cultivar registration is possible after 2 yr, providing the cultivars have exceptional merit as defined in the committee guidelines (Western Canada Canola and Rapeseed Recommending Committee, 2001). Registration is granted by the CFIA after formal request by the breeder(s) or representative of the cultivar. Seed sales of named cultivars are prohibited by law in Canada until such registration is granted.
Although the data required for cultivar registration are public information, most producers do not have ready access to them. The first opportunity for producer evaluation comes from the first year Regional Trials conducted independently by each province. A cultivar may enter the trial after the first year private trial with permission of the provincial coordinator. The breeder assumes the risk the cultivar may not receive registration approval. Provincial Regional Trials data are widely distributed to producers in provincial publications (Alberta Agriculture, Food, and Rural Development, 2003).
The regulation of all transgenics in Canada falls under the mandate of the CFIA and Health Canada. The CFIA is responsible for unconfined release of transgenics into the environment, and requires each transgenic to undergo stringent safety assessments before release (Plant Biosafety Office, 2000). These include human food, livestock feed, and environmental safety. The proponents of the transgenic construct are required to submit their data collected under regulatory guidelines, and data must show that the mandatory tests have been completed. The agencies review the data, and if acceptable, confined field testing will be allowed. Under certain circumstances, confined release can take place concurrent with cultivar testing in the co-op system, although recent changes in the regulations target the separation of these two activities (Grant Watson, 2001, personal communication).
The policies developed by Canadian federal agencies, CFIA, and Health Canada to assess transgenic crops are based on the view that the product is regulated and not the process. Therefore, if a transgenic crop is deemed to be substantially equivalent to the nontransgenic crop, it is generally considered safe for consumption. Approval of a particular transgenic event is usually forthcoming, following careful review of the data package submitted by the inventor.
The approval process for registration of transgenic cultivars is similar to that for nontrangenics. All breeding lines with approved constructs are treated as all other cultivars in that they are placed in unsprayed trials with conventional checks. The same data package is assembled as with the nontransgenics and submitted for approval by the WCC/RRC. Additional data required for HT transgenics relate to cultivar tolerance to the respective herbicide. Tolerance trials are conducted by the breeding company sponsoring the cultivar under the following guidelines: (i) trials must be conducted at a minimum of three locations in a four-replicate test, and (ii) must include seed yield, oil content, protein content, and chlorophyll content of each breeding line sprayed at 2 x the recommended rate at the two- to four-leaf stage, and under unsprayed conditions. The unsprayed nontransgenic checks must also be included (Western Canada Canola and Rapeseed Recommending Committee, 2001). The tolerance data package demonstrates whether or not there are detrimental herbicide effects on the performance of a cultivar. The data package forms part of the total submission to the CFIA when approval for registration is granted by the WCC/RRC, and the sponsor of the line requests registration of the cultivar.
Transgenic canola was introduced in Canada in 1995 (Monsanto Co., 2001, personal communication). Canola was one of the first crops to be transformed because of the ease with which this crop responds to both conventional and molecular genetic manipulation (Kott et al., 1990). At the time, two types of herbicide tolerance were available to be tested in the marketplace: Roundup Ready (GT73 construct) and Liberty Link (HCN92 construct). When the first transgenic cultivars were submitted for approval, no guidelines were available from the WCC/RRC to evaluate the material, although the lines would have been field-tested previously under confined release, isolation, and production guidelines provided by CFIA. Consequently, new transgenic breeding lines were included in the regular WCC/RRC testing program. Since they were a new cultivar class, extra merit points were assigned to compensate for their slightly lower performance in relation to the checks and to ensure they were given a fair exposure in the marketplace during the first years of testing.
After the transgenic candidate cultivars had gone through the regular registration process in 1995, commercial production became possible. There was uncertainty as to an appropriate marketing plan at the time. Following thorough discussions between the seed trade and the breeding organizations responsible for the development of both Liberty Link and Roundup Ready cultivars, the seed trade agreed that they would produce only enough product for a closed-loop domestic production and distribution system. This was done to ensure there would be no harm to the industry resulting from any unforeseen marketing problems, as no approval was available for sale of transgenic products in off-shore markets. When approval in Japan, the most important off-shore market, was obtained the following year, transgenic canola began to move through the regular seed channels without prejudice. The European market, however, remained closed to transgenic crops and their products. In Canada, there was very close cooperation among all segments of the canola industry to ensure that the new products entered the marketplace in a timely and orderly fashion, with minimal disruption to the industry.
Although initial transgenic cultivars were slightly inferior to the standard cultivars of the day, breeding progress was rapid. Today, cultivars utilizing Roundup Ready and Liberty Link technologies are at least as productive, and in many cases superior to conventional cultivars, with equal quality to the nontransgenic check cultivars. Also, no evidence is available to date suggesting the performance of transgenic cultivars are affected in any substantial manner by spraying of their respective herbicides. In a randomly chosen sample of cultivars representing each transgenic HT type, all sprayed cultivars were similar in their performance to the nonsprayed controls (Tables 1–3) . Although the bromoxynil (OXY235 construct) cultivars (approved in 1997) are at present inferior to the standard check (2000, unpublished data), rapid improvements are anticipated. In fairness, the breeding history of these cultivars has been much shorter than the others.
|
|
|
55% of the total western Canadian canola acreage (Canola Council of Canada, 2001). The survey found that producers embraced the technology more for ease of weed control rather than economic advantages, despite the documented yield advantages of transgenic cultivars (Table 4)
.
|
Consumer acceptance of transgenic canola has generally been very good in Canada and its trading partners, except in Europe where there is a ban on the use and sale of transgenic canola and its products. Recent attempts by certain consumer groups in Canada to sway public opinion to reject the use of products derived from transgenics has largely proven unfruitful. The furor has raised the issue of voluntary and/or mandatory labeling of transgenic products. This may be important to consumers in the future as new transgenic products are released for consumption. For now, the Canadian Government has rejected proposed legislation mandating labeling of products of transgenic organisms.
It is fully appreciated by the developers of transgenic canola technology that not all tolerance tests can or will be conducted on every transgenic cultivar. For example, the herbicide effects on traits such as lodging and seed size have not been extensively studied in new cultivar releases. The effects on quality components such as fatty acid composition of the oil have been examined for the initial approval of the technology; however, these tests are not currently required for registration (except for saturates), and are considered to be of lesser importance than the major agronomic and quality traits such as yield, maturity, and oil and protein content. These issues relate to the time involved and the perceived necessity of the tests, with respect to return on investment.
During the expansion of the transgenic technologies into canola cultivars, a rapid decrease in public resources to fund such research became apparent. This meant that more of the burden of proof fell to private industry, which has resulted in reduced-tolerance research and the associated broad-based testing for all parameters. Furthermore, there are no standardized conditions specified as to how the field trials are to be conducted, such as till vs. no-till, uniformity of seed source, and soil tests. Because of costs, all trials must be conducted on a small-plot basis rather than field-scale replicated strip trials. Strip trials require a large land base, and are generally not suitable for tolerance trials because of their size and the difficulty in employing replication.
Canada is currently undergoing a cultivar registration review, and draft proposals suggest the country may be moving more toward a U.S. system where national registration is not required for cultivar release. If these changes occur, then cultivar release requirements currently in place in Canada will likely be reduced, resulting in an erosion of the present regulations for herbicide tolerance testing in Canada.
Received for publication July 5, 2002.
|
REFERENCES |
|---|
|
TOPABSTRACTREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  J. Wan, R. Griffiths, J. Ying, P. McCourt, and Y. Huang Development of Drought-Tolerant Canola (Brassica napus L.) through Genetic Modulation of ABA-mediated Stomatal Responses Crop Sci., August 7, 2009; 49(5): 1539 - 1554. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Vadose Zone Journal | |||
| Journal of Natural Resources and Life Sciences Education |
Soil Science Society of America Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
