China's Perennial Rice 23 (PR23) was ranked in Science's top 10 breakthroughs in 2022.

Rice, like other world's major food crops, must be planted anew for every harvest. This means a lot of work for farmers and a burden to environmental problems, such as soil erosion. But with PR23, farmers' burdens can be eased.

Once planted, PR23 can be continuously harvested without tillage for three to four years. From the second season, farmers do not need to buy seeds, cultivate seedlings, plow, or a transplant, but only need to make field management and harvest. This helps to save production costs.

The variety marks a milestone in the field of perennial food crops based on interspecific hybridization.

PR23 was created years ago by crossing a commercial variety of Asian rice with perennial wild rice that grows in Africa.

In 2018, researchers at Yunnan University and other institutions released the variety to farmers in China, enlisting them in a large-scale experiment.

In November 2022, researchers published a thesis in Nature Sustainability, reporting that PR23 yielded just as much grain as regular and seasonally planted rice.

Other scientific breakthroughs in Science's list include NASA's James Webb Space Telescope, the finding of a surprisingly massive microbe, a new insight into the Black Death, and an ancient ecosystem reconstruction.