> Government's statutory advisors on the release of
> genetically engineered crops into the environment,
> stated that "at a standard separation distance of
> 200 metres between the organic sweetcorn and the GM
> maize the likely cross-pollination frequency would
> result in no greater than 1 sweetcorn kernel in
> every 40,000 being a GM hybrid"(5). However, Dr
> Jean Emberlin, having looked at all the research
> available, concluded that "in conditions of moderate
> wind speeds the rates of cross-pollination at 200
> metres would be in the order of 1 kernel in 93."
The truth is probably somewhere in between. Using the standard isolation of
200 meters from commercial corn, we routinely produce seed with well under
1% outcrossing. The rate of introgression of field corn pollen into
sweetcorn will usually be less than that for the following reasons:
1. The sweetcorn production field has 5 times more plants shedding pollen
than a seed field planted in the typical 4:1 (female to male) row pattern.
2. Sweetcorn plants produce way more pollen than modern field corn, swamping
potential contamination.
3. Sweetcorn crops often flower earlier than adapted field corn.
> Evidence is cited in Dr Emberlin's report that maize pollen
> is collected by bees in notable amounts. In this way the
> pollen is transported several miles
Bees work the tassels for pollen to eat. They don't work the silks.
But, rather than argue theory, why don't those of you who produce "organic"
sweet corn find out experimentally. In several spots in the field at
increasing distances from the foreign pollen source, leave some ears
unharvested for at least a week past the eating stage (preferably longer).
Pick the ears and dry them slowly. Keep the ears from the different spots
in the field separate. Examine the ears for starchy kernels. Pollination
by field corn (or certain other kinds of sweetcorn) will result in starchy
kernels because starchiness is dominant. I'll bet you'll usually have to
look at a lot of ears to find any starchy kernels (unless you have a really
small patch of sweetcorn).
> The Soil Association is calling on the Government to honour
> these pledges and provide a response to this report with
> the utmost urgency in order to avoid potential cross-
> pollination from GE trial plots due to be planted in 1999.
I guess I don't understand the sense of urgency. After all, half the world
is eating transgenic crops all the time now. If it were so dangerous, don't
you think we would notice a problem? Eating that one out of 10,000 or so
GMO-pollinated kernels in your sweet corn is a purely esthetic problem.
Dale
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