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transgene contamination of seed stocks



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Transgenic Contamination of Certified Seed Stocks

Yet more evidence that transgenic contamination is inevitable and
unavoidable. Prof. Joe Cummins reports.

The spread of transgenes from genetically modified crops is a great
threat to the quality of certified seed. Canola (oilseed rape in the UK)
(Brassica napus, B. rapa, B. campestris) is the second most valuable
crop in Canada. The Canadian Food Inspection Agency (CFIA), a sub
department of Agriculture Canada, requires a distance of 200 metres
separation between fields growing certified seeds from any other
Brassica, and a distance of 50 metres from weedy relatives. Recently,
however, producers of hybrid canola seed have required a separation of 2
kilometers from a Brassica crop, in recognition that pollen from a
Brassica crop may travel as far as a kilometer or more. CFIA separation
distances are evidently inadequate for insuring the purity of certified
seeds.

Friesen, Nelson and Van Acker in the University of Manitoba in Winnipeg,
Manitoba, Canada, studied certified canola seed stocks for contamination
due to transgenes for herbicide tolerance to glyphosate, glufosinate or
thifensulfuron [1]. Certified seed stocks were studied in field plots to
which herbicides were applied. The results showed that 95% of 27
certified seed lots were contaminated with herbicide tolerance
transgenes; with 52% of the seed lots exceeding the 0.25% maximum
contamination standard set for certified seed. Some lots were tolerant
to both glyphosate and glufosinate.

A year earlier, Downie and Beckie from AgriFood Canada in Saskatoon,
Saskatchewan [2], examined 70 certified canola seed lots using a
laboratory Petri dish assay. They found 59% of the seed lots had
detectable herbicide tolerance and 25% had contamination levels
exceeding the maximum acceptable standard for certified seeds. The
standard for cross contamination was established for conventional not
transgenic cultivars, and presently, there are no standards for
transgenic contamination of certified cultivars in Canada. Standards for
transgene contamination of canola oil or oilseed cake for animal feed
would be desirable, and even necessary for export purposes, given the
requirements for labeling and traceability in Europe.

The extensive contamination of certified canola seed with transgenes for
herbicide tolerance is staggering. The Canadian canola crop extends over
some 5 million hectares, of which roughly 60% are planted with
transgenic varieties. The extensive cross contamination by transgenic
varieties could have been foreseen and predicted at the time field
trials of transgenic crops were carried out. By now, it seems unlikely
that transgene- free canola can be produced in western Canada. It is
disturbing that CFIA appears to be totally unconcerned over the
extensive contamination, which is evidence of gross negligence in
oversight on its part.

  1. Friesen LF, Nelson AG and Van Acker RC. Evidence of contamination
of pedigreed canola (Brassica napus) seedlots in western Canada with
genetically engineered herbicide resistance traits. Agron. J. 2003, 95
(in press).
  2. Downey RK, and Beckie H. 2002. Isolation Effectiveness in Canola
Pedigree Seed Production. Internal Research Report, Agriculture and
Agri-Food Canada, Saskatoon Research Centre, Saskatoon, Saskatchewan,
S7N 0X2, Canada, 2002, 14 pp.


This article can be found on the I-SIS website at
http://www.i-sis.org.uk/TCCST.php