Scientists create low-methane rice

July 22, 2015 by Mariette Le Roux
A vendor sells rice at a market in Jakarta on February 4, 2011
A vendor sells rice at a market in Jakarta on February 4, 2011

Scientists said Wednesday they had created a rice variety with starchier grains that emits less methane, a step towards the twin goals of feeding more people and curbing global warming.

The cultivation of rice, a staple starch for billions of people, is also mankind's major emitter of , a potent climate-altering gas.

Methane lives for a shorter time in the atmosphere than carbon dioxide (CO2), the most abundant greenhouse gas, but traps far more heat radiated from Earth's surface.

Every year, rice paddies pump out 25 to 100 million tonnes of methane—the second-most important greenhouse gas at about 16 percent.

This means a high risk for the planet as rice cultivation expands to feed a growing population, said the paper, published in the journal Nature.

"There is an urgent need to establish sustainable technologies for increasing while reducing methane fluxes from rice paddies," wrote the team led by Chuanxin Sun of the Swedish University of Agricultural Sciences.

Already in 2002, scientists reported that the more grain carried by rice plants, the less methane they emitted.

The leaves and stems of rice plants take up CO2, which is transformed through photosynthesis into sugars that are used to produce starch in the shoots, roots and grains.

Indian labourers plant rice paddy cuttings in a field on the outskirts of Amritsar on June 16, 2015
Indian labourers plant rice paddy cuttings in a field on the outskirts of Amritsar on June 16, 2015

Carbon released from dead plants, or directly into the soil via the roots, is transformed by microorganisms into methane, which can escape into the atmosphere.

Larger, starchier rice grains mean there is less carbon transferred to the soil to be turned into methane.

But attempts to reduce emissions from paddies have focused on changes in farming practices, which can be onerous and expensive.

'Groundbreaking' work

Tackling the problem differently, a team from China, the United States and Sweden added a barley gene to a conventional rice cultivar to create a variety dubbed SUSIBA2.

"Three-year field trials in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant reduction in methane emissions," said the study.

"SUSIBA2 rice offers a sustainable means of providing increased starch content for food production while reducing from rice cultivation."

In a comment also carried by Nature, Paul Bodelier of the Netherlands Institute of Ecology described the research as "groundbreaking", but cautioned it also raised several "biological and ethics concerns".

"In addition to the general questions surrounding the use of genetically modified crops for human consumption, and how access to seed for such crops is controlled, we do not yet have a clear picture of how this modification affects plants' survival and general function," said Bodelier.

Long-term measurements of methane emissions would be needed to calculate the crop's potential overall impact on reduction efforts, he wrote.

Also, the reduction of carbon in soil may have unknown consequences for other types of microorganisms that could aid or harm the plants.

All said, the work should spur scientists worldwide "to conduct experiments to verify whether this variety will enable more sustainable cultivation of the crop that feeds half the human population," said Bodelier.

Explore further: Soil microbes accelerate global warming

More information: Nature DOI: 10.1038/nature14673

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6 comments

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leetennant
5 / 5 (3) Jul 22, 2015
Such an amazing achievement!
docile
Jul 23, 2015
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Torbjorn_Larsson_OM
3.7 / 5 (3) Jul 23, 2015
Here we have a burning problem [sic!] and of course just because targeted gene modifications are new, people raise unsupportable concern - never mind that targeted techniques are more efficient and involve less change than other artificial selection that has been around for 10 kyrs. :-/

@Lee: Agreed!

@docile: Not agreed!

- The question of method choice is not whether or not it is "natural" but if it is efficient. That development strategy mistake is even a fallacy, appeal to nature. [ https://en.wikipe...o_nature ]

- Fish farming is highly problematic. "Tilapia raised in inland tanks or channels are considered safe for the environment, since their waste and disease is contained and not spread to the wild.[6] However, tilapiines have acquired notoriety as being among the most serious invasive species in many subtropical and tropical parts of the world." [ https://en.wikipe..._tilapia ] Fish are also zoonotic as hell.
docile
Jul 23, 2015
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docile
Jul 23, 2015
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geokstr
1 / 5 (1) Aug 09, 2015
IMO http://i.filmot.org/E94BDt6.gif, how to reduce the methane pollution from rice crops without need of GMO's - convert it into fish meat, which we can eat too. In addition, the farming of tilapia inside the rice crops will decrease the consumption of fertilizers, increase the yield of rice by at least 10% and it can be applied to whatever cultivar of ice, suited and adopted well for climate in given area.


Reminds me of why WC Fields said he didn't drink water, "Because fish f*ck in it."

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