Some of the new canola (B. napus) lines descend from the combination of two induced mutant traits ‘higholeic’and‘lowlinolenic’asshownforthecanola lines ‘45A37’ and 46A40. They have been developed through the combination of induced mutagenesis of cultivars ‘Regent’, ‘Topas’ and ‘Andor’ and crossing withlowlinoleniccanolasStellarandApollotoobtain high oleic acid trait. The processed oil of these lines
has evenhigherlevels of oleic acid than that of peanut and olive. It is considered that the induced mutation in these lines is similar to that in fad2 mutants of Arabidopsisthaliana(Health Canada, 1999). Microspore mutagenesis has also been used in combination with in vitro screening for the development of B. napus tolerant to the herbicides imidazoline and chlorosulfuron (Swanson et al., 1988). A further development has been the cloning of acetohydroxyacidsynthase (AHAS) genes from microspore mutagenesis and their transgenic transfer into canola for breeding herbicide resistant cultivars. Plants with these mutatedgenesconfera highlevel oftoleranceto sulfonylureas (e.g. chlorsulforon) and imidazolinones widely used as herbicides. The primary action site of these herbicides is the enzyme AHAS (Huang, 1992).