[BEIJING] Chinese scientists have identified a rice gene that could simultaneously control the crop's yield, plant height, and number of days to flowering.

Publishing their study in Nature Genetics online this month (4 May), researchers from Wuhan-based Huazhong Agricultural University (HZAU) say the gene could play a role in improving rice productivity.

The scientists found that in individual rice breeds, the three traits appear strong –– or weak –– simultaneously.
"This fact makes us infer that the three traits were controlled by a single gene," says Xing Yongzhong, one of the lead authors and a professor at HZAU.

Previous studies have found that a region on chromosome seven of rice can regulate all three traits but the specific gene involved had not been discovered.

The HZAU scientists mapped the relevant gene site on chromosome seven and located the specific gene named Ghd7. They discovered that shorter rice plants with fewer grains per cluster of flowers and earlier flowering do not have the gene Ghd7.

When they transferred Ghd7 into Ghd7-free varieties of rice, they found that time to flowering was increased by 105 per cent, they grew around 70 per cent taller, and the plants had more rice grains per cluster of flowers.

Numerous rice genes have been reported to control such traits alone, but Ghd7 is notable because of its large, multiple effects on an array of traits, write the authors.

Xing told SciDev.Net that the gene could be incorporated into varieties with traditional breeding. "Although we have used the genetically modified method in the study, we need not adopt this method in the practical seeding because the gene is identified from the rice itself."

The team of scientists also studied the status of Ghd7 in 19 rice varieties from rice growing in a wide geographic range in Asia and found five different versions of the gene.

"We are exploring the subtypes of Ghd7-containing rice that are most suitable to their growing regions, so as to cultivate the most appropriate high-output rice varieties," Xing adds.

Huang Dafang, former director of the Institute of Biotechnologies of the Chinese Academy of Agricultural Sciences, welcomes the study as a major scientific breakthrough.

But he says that usually, multiple genes regulate the traits related to rice yields, and whether the Ghd7 could play its claimed role in promoting yields needs further research and seeding tests.