Cross-pollination risk low scientists
WELLINGTON -- Genetically modified oilseed rape on
a Canadian farm is suspected of cross-pollinating with
natural crops.
But similar cross-pollination --
criticised by opponents of
genetic modification technology
as "transgenic pollution" -- is
unlikely to happen in New
Zealand field trials, experts say.
The growing of genetically
modified potatoes and sugar-beet has been allowed on
two different test sites in Canterbury, the former to resist
soft rot and tuber moths and the latter to resist a
herbicide.
The Environmental Risk Management Authority, which
approved the testing, said the risks of adverse effects
were negligible.
The modified beet is being grown by Wrightson
subsidiary Kimihia Research Centre in a contained field
near Christchurch, and the potatoes are being grown on a
research farm at Lincoln by the Institute for Crop and
Food Research.
The vegetables will be destroyed once the trials are
completed.
According to a recent issue of the British publication
Farmers' Weekly, a Canadian oilseed rape (also known
as canola) grower who had planted a genetically modified
variety in a field was surprised to see it growing
elsewhere in a field of conventional crops. The farmer
believed the genetic trait was transferred by pollen
movement. The authorities are investigating.
ERMA chief executive Bas Walker said that unlike the
oilseed rape on the Canadian farm, the modified potatoes
and beet were being grown here in contained areas.
Strong monitoring had been imposed to avoid release of
genetic material.
With the beet, all flowering stems were removed before
the flower buds opened, preventing cross-pollination.
A 6m-wide buffer crop of ordinary potatoes would be
planted around the potatoes.
Institute scientist Dr Tony Conner said berries and flower
buds were being removed from the modified potatoes.
The trial site, which will be kept fallow for three years
after the experiment, would be monitored for any
spontaneous plant growth. Apart from the buffer zone,
the nearest potato crop was 1km away.
The Canadian incident involved the commercial growing
of a modified crop only 30m away from conventional
crops.
Monsanto research and development manager Murray
Willocks said no cross-pollination had occurred in New
Zealand oilseed rape crops because genetically modified
canola had not been generally released here.
In New Zealand, where at least 15 new plant varieties
have reached field trials since 1988, scientists have said
few cropping plants have the weedy characteristics
needed to survive outside cropping situations, and when
crop plants crossed with wild species, the progeny were
usually not fit for the natural environment.
But scientists have also said the risk needed
commonsense assessment -- developing herbicide
resistance in New Zealand oats might be considered
unwise, given existing problems with wild oats.
Recent studies have also shown that when weeds acquire
herbicide resistance from genetically engineered crops,
they maintain their ability to pass these traits on.
A comparison of the fertilisation rate of plants that were
mutated to make them resistant to chlorsulphuron
herbicide, and plants that were genetically altered for the
same trait, showed the genetically altered plants fertilised
other plants at a rate 20 times greater than that of the
mutants. -- NZPA
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