A groundbreaking new rice variety developed through traditional crossbreeding methods has the potential to cut methane emissions from rice cultivation by nearly 75%. This innovation comes as rice farming accounts for approximately 12% of global anthropogenic methane emissions, a greenhouse gas that is 25 times more potent than carbon dioxide in its warming effects.
Methane emissions primarily arise from soil microbes in flooded paddy fields, where they decompose root exudates produced by rice plants, generating methane in the process. Researchers conducted experiments using two strains of rice: the Japanese cultivar Nipponbare, known for average methane emissions, and the genetically modified SUSIBA2, which is engineered to emit less methane. The study revealed that while SUSIBA2 produced less fumarate—a key contributor to methane production—its lower emissions were also attributed to a significant release of ethanol, which appears to inhibit methane generation.
To further enhance sustainability, the research team turned to conventional breeding methods, developing a new strain by crossing a high-yield elite variety with the low-fumarate, high-ethanol producing Heijing cultivar. Results from two years of field trials in China showed that this novel strain achieved impressive yields of over 8 tonnes per hectare, starkly higher than the global average of just over 4 tonnes, and reduced methane emissions by 70% compared to the elite variety.
The study exemplifies successful research targeting greenhouse gas emissions in agriculture without resorting to advanced genetic engineering techniques. A notable researcher highlighted that the focus on traditional crossbreeding methods underscores the potential for developing rice lines that mitigate methane synthesis effectively.
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