Genetic modification rapeseed

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. 

Finally, genes required for particular aspects of fatty acid and triacylglycerol biosynthesis can be identified in appropriate sources, cloned, and transferred to other plants. Rapeseed has proved to be particularly flexible in this respect, and its fatty acid composition has been modified in several ways, some of which have now reached or are very close to commercial application (Section 9.4). Genetic modification procedures are also applied to soybean and other oilseed crops. 

Genetic modification of rapeseed to produce a high-stearate oil using antisense technology to reduce expression of stearoyl-ACP desaturase was reported in 1992 by Knutzon et al. When tested in the field, lines from the first modified plants showed stearate contents between 20 and 30% with total saturates slightly above 30%. Seed yield and germination under standard conditions were normal. 

As shown in Table 1, rapeseed/canola, sunflower, soybean, and safflower can all be modified by traditional breeding methods or by genetic modification to produce high-oleic varieties containing >70-90% oleic acid. The content of saturated acids is generally <10% and is lowest in the modified canola oils. 

---