About half the world's population eats rice as a staple. Two-thirds of the diet of subsistence farmers in India and Bangladesh is made up entirely of rice. If rice crops suffer, it can mean starvation for millions.
"People [in the United States] think, well, if I don't have enough rice, I'll go to the store," said Ronald, a professor of plant pathology at UC-Davis. "That's not the situation in these villages. They're mostly subsistence farmers. They don't have cars."
As sea levels rise and world weather patterns worsen, flooding has become a major cause of rice crop loss. Scientists estimate 4 million tons of rice are lost every year because of flooding. That's enough rice to feed 30 million people.
Rice is grown in flooded fields, usually to kill weeds. But rice plants do not like it when they are submerged in water for long periods, Ronald said.
"They don't get enough carbon dioxide, they don't get enough light and their entire metabolic processes are thrown off. The rice plant tries to grow out of the flood, but when it does, it depletes its sugar reserves. It starts to break down its chlorophyll, important for photosynthesis. It grows really quickly, and then when the flood recedes, it just dies. It's out of gas."
Normal rice dies after three days of complete flooding. Researchers know of at least one rice variety that can tolerate flooding for longer periods, but conventional breeding failed to create a strain that was acceptable to farmers.
So Ronald and her colleagues -- David Mackill, senior scientist at the International Rice Research Institute in the Philippines and Julia Bailey-Serres, professor of genetics at the University of California-Riverside -- spent the last decade working to find a rice strain that could survive flooding for longer periods.
Fighting hunger with flood-tolerant rice (cnn.com)