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Date: | Sun, 18 Mar 2007 06:53:55 -0400 |
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Bill Truesdell wrote:
> I would love to see the full study done on bees preferring non-GM
> crops since all I can find are abstracts which leave more questions
> than answers. Especially since they talk of both B. napus and B. rapa.
> The latter piqued my curiosity.
Peter Borst kindly sent me the full study. I was correct that the
organic farmer had B. raps and the GM crops were B. napus. The
intermediate farms could have combinations of both.
The use and twisting of the abstract was even worse than I thought. The
pollination deficit was not really a deficit but the difference that can
be obtained with pollination on B. napus compared to not pollinating it.
Also interesting is that the self pollinating B. napus produced as many
seeds without pollinators as the pollinated organic B. rapa. But B.
Napus has larger seeds so the yield from the GM fields was actually
greater than the organic.
The B. rapa in the organic fields should have had many more seeds than
B. napus, so the organic method was not optimum for seed production.
That came across if you noted that the organic field suffered from
fairly high pest damage. That would explain the observation of about
equal seeds between B. rapa and B. napus, which, all things being equal,
B. rapa should have had more seeds.
So what we can actually deduce from the study is B. napus benefits with
additional pollination and will then have up to 33% more (and larger)
seeds than a pollinated organic field. That the organic field is not
optimum for seed production because of pest damage and the GM field
outproduces it (same number of seeds but larger seeds) even without
pollination.
Also interesting is that the GM fields were large and organic fields
were small, so you had more diversity in the organic area than the
mono-crop GM. The organic fields were so small that the researchers
could not go the same distance into the field as the GM fields or they
would be out of the organic field or back by the edges. So you had
closer access to other plants and nectar sources.
GM fields were also sprayed with pesticide, which did not help the
pollinators. Some of the fields were further north and there were no
bees. Since B. napus does not need pollinators, one could assume that
they were in this region. With all that it is sort of obvious that there
would be more pollinators on the organic fields. We do not even know if
the organic farmer/s kept bees.
The third group, which was between organic and GM fared the worst. There
was another study I read, trying to find this one, that looked at the
issues between pure GM and other strategies for growing canola. They
found that the problems were such that the in-betweens fared worst, not
because of pollination but plant gender, bloom times and distribution
of plants. That same study discussed the numbers of empty pods on all
canola varieties. Even if pollinated, many pods just do not set seed,
and they have no good idea why.
There is also a bloom time difference and bloom duration difference
between varieties. Lots more going on than any good scientist would
like. Got to control the variables. All the trial was set up to do was
see if pollination made a difference and it did with the self
pollinating B. napus. But that has been shown in earlier studies. Many
self pollinators fare better with pollinators.
Completely different than the propaganda that bees shunned the GM crops.
What does come from the study is that pollinators help to optimize
yields on self pollinating canola; they are in short supply; and the
more you can get the better off you are.
Or bees are good.
Bill Truesdell
Bath, Maine
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