Increased output

Salt-tolerant rice can grow in saline soil with water containing 0.6 percent salt, which covers a relatively high percentage of China's saline soil, thus increasing the nation's rice production.

Zhang Guodong, vice-director of the Qingdao research center, said, "Quite a high proportion of saline soil in China has a salt content of more than 0.6 percent, but by watering the rice plants, we keep the salt content in water surrounding their roots at around that level, thus helping them grow well."

In 1930, it was discovered in Ceylon — now Sri Lanka — that wild rice could grow in saline soil, marking the start of research in this field.

In comparison, such research in China did not begin until the 1980s, when Chen Risheng, an agricultural scientist in Zhanjiang city, Guangdong province, found that some rice plants could grow on the coast in this area.

Chen collected more than 500 seeds and grew them on an area of local wetland. After five years, he harvested 3.8 kg of seeds that had grown steadily — naming the crop Sea Rice 86 to mark the year in which he made the discovery.

After decades of research, China took the lead globally in seawater rice research thanks to the late academician Yuan Longping, known as the "father of hybrid rice", and his team.

Zhang said, "Seawater rice breeding is part of hybrid rice breeding, in which China has long been the undisputed champion of the world." In 2012, Yuan and Chen set up a team to research seawater rice. By 2016, Yuan had coordinated national resources and founded the Qingdao Saline-Alkali Tolerant Seawater Rice Research and Development Center.

Yuan set three goals for the pair: Seawater rice must be able to withstand water with a salt content of 0.6 percent or more, thus saving water resources; to be economically sustainable; the yield must reach 300 kg per 0.67 hectares; and the total plantation area should be more than 6.67 million hectares for planting seawater rice to be a sustainable industry in China.

The Qingdao center turned to a range of innovations to work toward these goals, including gene sequencing to locate genes that enable the rice plant to tolerate salt and alkali, and hybrid breeding to accumulate as many salt-tolerant genes of a single rice plant as possible to reproduce such plants.

The center also signed contracts with China Aerospace Science and Technology Corp for seawater rice seeds to be transported into space.

The measures adopted enhanced the efficiency of breeding seawater rice. On Dec 5, the first batch of rice seeds grown in space returned to Earth with three astronauts on the Shenzhou XIV spaceship after spending 120 days on China's space station.

The first two goals set by Yuan have been met as a result of the measures taken.

In 2017, the Qingdao center developed seeds that yielded 620 kg of rice per 0.67 hectares in water containing 0.6 percent salt. In the past four years, the center has planted seawater rice on 6.67 million hectares of land nationwide, yielding a record-high 698.4 kg per 0.67 hectares last year.

In addition, Chinese teams have received invitations from nations with large areas of saline soil to share their technologies with them.

In July 2018, Khaleej Times, which is based in Dubai, United Arab Emirates, reported that a team of Chinese scientists had started harvesting rice in diluted seawater, aiming to cover about 10 percent of the UAE with paddy fields to increase grain output on the sand-covered land.

Chinese teams are now cooperating with local officials on seawater rice projects in many other countries.