RICE plants usually love warmth. But when they start to flower, hot nights can result in meager harvests and chalky grain. So far, breeders have made slow progress in solving these challenges, which are becoming more urgent with climate change.

Now, after searching for more than a decade, researchers from Huazhong Agricultural University in Wuhan, capital of Central China’s Hubei Province, have found a culpable gene, which they describe last week in the journal Cell. They also show that a natural variant of the gene can preserve both yield and rice quality when temperatures rise.

“This paper is a major breakthrough,” says Argelia Lorence, a plant biochemist at Arkansas State University who studies heat stress in rice. The impact could ultimately be even broader than rice, as the gene is present in other cereals, such as wheat and corn, which suffer similar problems with heat.

The Chinese researchers planted 533 types of rice in four locations in China where nights have gotten warmer. After harvest, they assessed grain chalkiness by simply counting grains that were white rather than translucent. Two research varieties did particularly well: Chenghui448 and OM1723. By crossing them and tracking genetic markers in the hybrids, the team homed in on a “quality-thermotolerant” gene on chromosome 12, which they named QT12.

Under high temperatures, QT12 interacts with the protein complex NF-Y to protect rice grains like a firewall inside the grains, deterring extreme heat while also stabilizing starch and protein synthesis, said Li Yibo, the corresponding author.

Li noted that, during last year’s high temperatures, the team conducted large-scale field trials in the Yangtze River basin. The results showed that inserting QT12 into the hybrid rice breed Huazhan increased yields by 49.1%, 77.9% and 31.2% respectively in the cities of Wuhan, Hangzhou and Changsha and improved quality.

Li said the Yangtze River basin produces around two-thirds of China’s rice, but extreme heat in recent years has threatened rice farming.

The discovery provides a novel molecular mechanism and breeding solution to achieve both high yield and quality in rice under a high-temperature environment, he said, adding that the team has partnered with domestic companies to accelerate breeding applications.(SD-Xinhua)