Thousands of farmers in China have started to grow a remarkable new version of rice, one that realizes an old scientific dream. It's a perennial form of the grain, which doesn't have to be planted anew each season, but emerges year after year from long-lived roots in the soil just as many wild grasses do.
Researchers at Yunnan University in Kunming, China, worked for more than two decades to create this rice, and have now revealed details of their success in the journal Nature Sustainability. Their perennial rice, they report, requires much less labor, dramatically reducing a farmer's costs while producing about the same amount of grain. Its long-lived roots may deliver big environmental benefits, too, although scientists need more data to confirm that.
"This is a really big deal. This is a change in the way that we think about agriculture," says Erik Sacks, a plant geneticist at the University of Illinois who collaborated with the Chinese scientists and co-authored the new study.
Some scientists, including Sacks, are hoping that this version of rice is a foretaste of future perennial crops that will transform agricultural landscapes, preserving vulnerable soil and enriching natural ecosystems. Other scientists are skeptical that this success can be replicated in other major crops such as wheat or corn.
Shilai Zhang, one of the leaders of the Yunnan University research group, wrote in an email to NPR that Chinese researchers first tried to create a perennial version of rice in the 1970s, but failed. They achieved a crucial breakthrough in 1996 by cross-pollinating a conventional rice variety with a relative of rice that grows wild in Africa, and is perennial. The resulting embryo wouldn't normally survive, but scientists used a laboratory technique called tissue culture to grow a new, hybrid rice plant from it. This plant had permanent living roots, like its African parent, but could also be cross-bred with standard cultivated rice.
Zhang and his colleagues grew thousands of offspring from this hybridization, trying to find a variety that was perennial, yet also delivered bountiful harvests of top-quality rice. "We failed again and again," Zhang wrote. Local farmers thought that they were only planting weeds, rather than true rice.
In 2018, however, the researchers finally had a perennial variety in hand that passed muster, and they released it to farmers in China. Other varieties went on the market two years later. They appear to be catching on. According to the researchers, about 11,000 small farms planted perennial rice in 2020, on a total area of roughly 9000 acres. A year later, the number of farms willing to try the new varieties had quadrupled, and the planted area jumped to 38,000 acres.
According to Zhang, many farmers are attracted to perennial rice because it takes less work. In some rice-growing areas of China, he wrote, "young people are moving away, and the rest of the rice producers are old." Perennial rice allows them to avoid the hard work, and the cost, of planting seed and transplanting seedlings into paddies each year. The Yunnan University researchers say that this cuts the cost of raising a crop roughly in half during the years when farmers don't have to plant it.
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