Of the things I get worked up over, genetically modified crops aren't that high up the list. (As an aside, I think the UK farm-scale trials of a few years back did a good job in showing that GM crops tended to reduce agricultural biodiversity, but that this was a result of the changes in farming methods associated ith them, rather than any property of the crop per se. Likewise, I think the issues around GM crops are more to do with big agribusiness controlling the food chain, loss of varietal diversity and so on, rather than that the technology is somehow immoral or that eating them is bad for you. It's striking that in places where they don't have the luxury of squeamishness about agriculture, such as India and China, GM is rather less of an issue.)
That said, I think this paper in Molecular Ecology by Suzanne Warwick et al is interesting. They show that herbicide resistance genes from oil-seed rape (Canola) have crossed into a weedy relative, Brassica rapa and set up home there (they've been there for 6 years, apparently).
"Most hybrids had the [herbicide resistance] trait, reduced male fertility, [and] intermediate genome structure", say Warwick et al. Whether they are more or less fit than the wild variety - and what consequences this has for the weediness of B. rapa - they don't say in the abstract. That's clearly something worth studying; I don't think panic is in order, but vigilance is, so well done to these researchers for playing the long game. Although by the time we find out we've created a super-weed it may be a bit late.