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Can transgenic crops create
November 20, 1996 - An article in the October 11, 1996 issue of
Science reported the opinions of an assortment of scientists on the potential for genes
moving from transgenic crops to wild plants, therefore creating a "superweed".
As might be expected, there were a wide range of views on this topic. The article reported
results of two studies that documented unusually high rates of gene flow between
cultivated varieties of sunflower and stawberry into wild types of the two species. In
sunflower, marker genes were found at a frequency of 28% in wild sunflower growing near
fields where sunflower had been grown as a crop for 10 years, whereas the frequency was
38% after 35 years. An ecologist from Clemson University reported that 50% of the wild
strawberries growing within 150 feet of a strawberry field contained marker genes from the
cultivated strawberries. This relatively high rate of gene flow between cultivated and
wild biotypes has raised the concern that genes from transgenic crops could move into wild
plants, thereby creating a superweed. Researchers in Denmark found than the same movement
can happen with genes from transgenic crops. They reported that a transgenic herbicide
resistance gene moved from oilseed rape to its weedy relative, field mustard (Brassica
Source: Science, Oct. 11, 1996. Vol. 274:180-181.
Prepared by Bob Hartzler, extension weed management specialist, Department of Agronomy, Iowa State University
more information contact:
ISU Extension Agronomy
2104 Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1923
Fax: (515) 294-9985
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