Abstract
With the increase in the use of genetically modified organisms (GMOs) in the last 15 years, the influence of GMOs on the environment continues to receive more attention within and outside the global scientific community. The distribution of herbicide-tolerant Brasica napus (2n=38) and gene flow to relative species, B. rapa (2n=20) and B. juncea (2n=36), have been investigated since 2003 in Japan. Using samples collected from the 12 areas including the major ports through which oilseed rape imports to Japan passed, the presence of glyphosate- and/or glufosinate-tolerant B. napus has been confirmed in 8 of these areas. Samples of B. napus that are simultaneously tolerant to 2 herbicides have been detected for 4 continuous years (2005–2008) in Yokkaichi area, suggesting the possibility of outcrossing between two kinds of herbicide-tolerant B. napus populations. Moreover, in 2008, a possible natural hybrid between herbicide-tolerant B. napus and B. rapa (2n=29) was detected at Yokkaichi site. We are going to continue the investigation thence, with focus on gene flow to feral relative species, and the possibility of persistence of these herbicide-tolerant plants in biodiversity.
