Flooded rice fields are a known source of anthropogenic greenhouse gas (GHG) emission—as per the Intergovernmental Panel on Climate Change, such fields generate enough methane to account for 20% of global warming. Over 90% of the world’s total wetland paddy cultivation happens in Asia. And the two top rice-growers in the continent, and indeed, the world, China and India—India accounted for over 22% global rice production in 2014—also happen to be two of the top overall GHG emitters. So, it is welcome news that Chinese scientists, as per a Nature report, in collaboration with researchers in Sweden and the US, have developed a strain of rice that can cut methane emission.
So far, increasing the yield has been the focus of rice research, and not cutting methane emission. For the latter, the minimal efforts undertaken have all been concentrated on modifying agricultural practices—moderating fertiliser usage, water management, etc. SUSIBA2, the new variety developed by Chinese scientists, is the harbinger of a biotechnological intervention that can meet the twin goals of increasing yield and reducing methane emissions. The strain was created by transferring genes responsible for starch production in stem and grains using transcription factor technology. Expression of the gene routes most of the starch produced by photosynthesis to the grains and stems, which means lesser than usual is available at the roots for soil microbes to process into methane. While scientists are pondering over what the large scale cultivation of such rice would mean for the survival of beneficial soil bacteria in the long-term, there can be no doubt that SUSIBA2 represents an important breakthrough for rice-growing nations.