2. Protoplast fusion to transfer desirable genetic traits, particularly those carried by cytoplasmic organelles (chloroplast, mitochondria). Transfer of cytoplasmic traits such as male sterility and herbicide resistance was made possible via protoplast fusion and microinjection techniques (39).

3. Selection of cell variants with desirable agronomic characteristics (eg, herbicide resistance, drought tolerance, winter hardiness) after treatment with mutagenic agents and selection pressure of treated cells.

4. Gene transfer using suitable vectors (Agrobacterium tumefaciens) or by microinjection techniques.

Consideration is primarily given to genes responsible for herbicide and fungal disease resistance, osmotolerance, manipulation of triglyceride composition, and production of novel high value chemicals (eg, jojoba-type waxes having as precursors eicosenoic and erucic acids).

Most prevalent among the novel-trait canola cultivars are herbicide-tolerant cultivars. Several B. napus varieties that are tolerant to the herbicides glyphosate (Round-up Ready), glufosinolate-ammonium (Liberty Link), and imi-dozolonone (Smart) are presently being grown in Canada. In fact, herbicide-tolerant varieties were estimated to account for 55 to 60% of the total acreage devoted to canola production in 1998 (47). By contrast, it was estimated that only 25 to 30% of the total acreage was devoted to transgenic herbicide-tolerant varieties in 1997. In addition to the development and testing offi. napus lines, several lines of herbicide-tolerant B. rapa also have been developed and are being tested for agronomic properties. The rapid development of transgenic canola varieties in Canada has been the result of effective collaboration among industry, government, and university researchers and the fact that canola breeding in Canada is conducted primarily by private industry, companies such as Pioneer Hi-Bred, Zeneca Seeds, Plant Genetic Systems (Canada) Lyd., Saskatchewan Wheat Pool, AgrEvo, Limagrain Canada, and Svalof AB (48). The impact of genetic engineering and conventional breeding is expected to result in even more valuable and versatile Brassica oilseeds in the future. Specialty oils and by-products for both food and industrial uses, which are within reach of today's breeders, are expected to influence the production and marketing of rapeseed/canola in the years ahead.

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