USDA Test; Higher CO2 Levels Promote Growth Of Weedy Rice; More Vigorous, Herbicide-Resistant
Oops.
EDIT
Agriculture Department scientists raised rice in controlled lab environments. They grew some in CO2 levels reflecting atmospheric concentrations from a century ago — through to what’s expected to exist in coming decades. And with each rise in CO2 levels, the weedy rice increasingly hybridized with the crop plants, reinserting wild genes that breeders had spent great effort to remove or modify.
The result was a diminishing of the value and quality of the cultivated rice — essentially transforming it into a weed, explains Lewis Ziska of the USDA Agricultural Research Service in Beltsville, Md. “That’s sort of the science fiction aspect of this,” he says. Likening it to Invasion of the Body Snatchers, “Whatever [seed] the good plant produces is now going to be bad seed.”
EDIT
For instance, the weedy rice began flowering earlier. Now its pollen production was in sync with crop plants (where previously, most feral rice had flowered too late to pollinate cultivated rice). In addition, the red rice grew taller stems and more flowers — each conferring additional reproductive advantages, since pollen production increased and its release from unusually tall stems allowed it to travel beyond the plant that produced it (most rice tends to be self-pollinating).
The ability of the feral rice to successfully cross with the crop plants tripled between the lowest and highest CO2 environments, the plant physiologists showed. The new seeds tended to be more fragile (with the hulls cracking easily — creating a grain that commands less money in the marketplace) and to have a diminished nutrient content. These impacts have likely been developing in rice fields over the past half-century, unbeknownst to farmers, Ziska says, as CO2 concentrations have been climbing. In addition, hybrids in the new tests retained the crop plant’s genetic immunity to a weed killer. Indeed, Ziska says, the latter feature may partially explain the diminishing value of herbicide treatments on rice in recent years.
EDIT
http://www.sciencenews.org/view/generic/id/340980/title/Science_%2B_the_Public__Rising_CO2_promotes_weedy_rice
