FILE - In this July 24, 2013 file photo, a combine harvests wheat along the Oregon-Washington border, southwest of Walla Walla, Wash. The source of a patch of genetically modified wheat found Spring

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FILE - In this July 24, 2013 file photo, a combine harvests wheat along the Oregon-Washington border, southwest of Walla Walla, Wash. The source of a patch of genetically modified wheat found Spring 2013 in Northeastern Oregon remains a mystery, and farmers say they are going ahead with plans to plant their winter crop in coming weeks. (AP Photo/Walla Walla Union-Bulletin, Jeff Horner File) less 

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Associated Press
Fri, Aug 30, 2013 11:33 PM EDT