Volunteer GM wheat, mischief or carelessness?

This episode began when an Oregon farmer, whose identity and farm's location are carefully kept secrets, noticed that at the time of spraying a fallow field to clear weeds in preparation for planting, 'volunteer' wheat plants (not planted by the farmer but that sprout spontaneously among other weeds) did not die when treated with the herbicide glyphosate, which Monsanto markets as Roundup Ready (RR). The farmer had planted two kinds of soft wheat the previous growing season, neither of which was RR tolerant as such wheat seed is not commercially available.

The farmer sent samples of those herbicide-resistant volunteer plants to scientists at Oregon State University (OSU) in Corvallis for analysis. “My first reaction was 'no, it can't be,' but the plants tested positive as transgenic for the CP4 gene [cp4 epsps], which is present in all RR crops,” says OSU weed science professor Carol Mallory-Smith, the first to analyze those samples. “How that trait got there, I have no idea, and it is still a mystery.”