A team of researchers in the Philippines and the US have identified a gene that enables rice to survive despite being submerged in water, allowing the development of new varieties that could withstand flooding.
According to the Philippines-based International Rice Research Institute (IRRI), the discovery, which has been tested on crops in India, would help overcome "one of agriculture's oldest challenges" and offer relief to millions of poor rice farmers around the world.
The institute said it hopes that the discovery would also greatly contribute to poverty reduction, as rice is the staple food for over three billion people worldwide.
IRRI noted that while rice thrives in standing water, like all crops it would die if completely submerged for more than a few days.
"The development and cultivation of new varieties are expected to increase food security for 70 million of the world's poorest people, and may reduce yield losses from weeds in areas such as the United States, where rice is seeded in flooded fields," it said.
The researchers from IRRI and the University of California's Davis and Riverside campuses used genetic mapping to identify a cluster of three genes that appeared to make rice plants vulnerable to flooding or enabled them to withstand total submergence when flooding occurs.
The team focused on one of the genes—Sub1A—a rice variety that is normally intolerant of submergence, which when "over-expressed or hyper-activated" becomes tolerant.
The scientists theorised that the Sub1A gene was probably successful in making rice tolerant to submergence because "it affects the way the plants respond to hormones that are key to the plant's ability to survive even when inundated with water".
Actual tests conducted in India showed the rice plants boosted with Sub1A were not only tolerant to being submerged in water but also produced high yields and retained other beneficial crop qualities.
The IRRI said development of submergence-tolerant rice varieties for commercial production is already underway in Laos, Bangladesh and India.
The researchers are now trying to identify all genes that are regulated by Sub1A and use this information to further improve tolerance to flooding and other stresses.
The discovery of Sub1A can take rice production technology to new heights since one-fourth of the global rice crop is grown in rain-fed lowland plots that are prone to seasonal flooding, said IRRI.