Genetically engineered rice that borrows a single gene from barley may dramatically reduce methane emissions in the atmosphere, at the same time yielding up to 50 percent more grain to feed the world’s population, a new study has shown.
Rice, being the world’s second most important grain crop following only maize based on production volume, is also one the largest sources of methane emissions. As the world population has grown, so has the need to cultivate more rice. Currently rice paddies are responsible for up to 17 percent of atmospheric methane – a natural byproduct of anaerobic breakdown of organic matter in flooded rice fields.
“Warm waterlogged soil and exuded nutrients from rice roots provide ideal conditions for methanogenesis in paddies with annual methane emissions of 25–100-million tonnes,” the study says.
In order to reduce the greenhouse effect buildup and offer more food to the world, the Swedish University of Agricultural Sciences has engineered a “high-starch low-methane-emission rice” capable of producing a strong yield in an ecologically friendlier manner, by making the roots smaller and grain bigger.
“It is expected that rice cultivation will need to increase” to feed the world’s growing population, wetlands microbe biologist Paul Bodelier, told LA Times. “Unless something changes, that will also mean increased methane emissions. Any reduction in this area is quite important.”
That is why biologist Chuanxin Sun, the author of the new study published in the Nature Journal, decided to add a single transcription factor gene from barley into the rice strain. The new GMO rice plants were then planted alongside conventionally grown Nipponbare rice in two small test fields in China.
The data measured by Sun’s team in the summer and fall focused on individual plant methane emission and starch levels the plants allocated to their seeds, stems and roots. Measurements were also taken on methane-producing bacteria around the plant roots.
The three-year field trials showed that, as predicted, the GM plants grew starchier grains than their traditional counterparts, and smaller root system with less methane-producing bacteria around it.
The methane emission of the modified plants was measured at less than 10 percent of the conventional rice, and down to 0.3 percent depending on the season. The modified strain also produced much more yield with dry weight of the rice grains increasing from 16 to 24 grams per plant.
While the initial measures might seem tremendous, scientists believe larger-scale trials are needed to draw more conclusive results and see how the controlled experiment works out in the field.
Moreover there are still biological and environmental concerns regarding the possibility of genetically engineered strain spreading in the wild, as GM rice has not been approved for commercial cultivations anywhere in the world.
Scientists however hope they could achieve similar results using traditional breeding methods and get a new strain of rice to the market in the next ten years.
“Right now of course it’s a GMO issue, and we cannot deliver this variety directly to farmers,” Sun told MIT’s Technology Review. “We have to use traditional breeding methods and breed the new, society-acceptable variety for farmers.”