A farmer operates a tractor to plough and prepare for sowing winter grain in Taihe county, East China's Jiangxi Province on October 27, 2022. Photo: VCG

Scientists from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences believe that the combination of the two genes — SD6 and ICE2, which regulate seed dormancy — would work together to prevent the loss of crops caused by pre-harvest sprouting.

Seed dormancy is an important survival mechanism for plants since it allows them to survive conditions not conducive to their healthy growth. On the other hand, excessive dormancy may lessen cultivation time. 

In response, farmers often plant low-dormancy cultivars of rice and wheat in order to achieve a higher, more uniform emergence rate after sowing. Unfortunately, this practice has led to a worldwide production problem called pre-harvest sprouting, which severely reduces both grain yield and quality.

According to the research team, in rice, pre-harvest sprouting damages about 6 percent of the acreage of conventional rice and as much as 20 percent of hybrid rice acreage due to the long-term wet weather during the harvest season in southern China. In bread wheat, the direct economic loss caused by pre-harvest sprouting is estimated to be near $1 billion per year.

Temperature has a major effect on the strength of seed dormancy. The researchers revealed that the SD6/ICE2 molecular module controls rice seed dormancy in a temperature-dependent manner.

SD6 is up-regulated to trigger seed germination when seeds are at room temperature. However, at low temperature, SD6 is down-regulated while ICE2 is up-regulated to maintain seed dormancy.

By editing SD6 in rice cultivars and wheat varieties, the scientists found that it would improve crops’ pre-harvest sprouting resistance.

China has been improving its capability for ensuring domestic food supply with higher annual output, contributing to global food security, and technologies related to crop seeds have become a major focus of efforts to ensure food security.
The number of national seed breeding and production bases in China increased to 216 amid the country’s efforts to bolster seed production, according to the Ministry of Agriculture and Rural Affairs in April.

In 2022, the nation's summer grain output hit 147.4 million tons, a record high. A bumper autumn harvest is also expected, as 97.6 percent of autumn grain nationwide had been harvested as of end-November, according to official data. 

Global Times