HAIKOU, Dec. 31 -- Chinese scientists have cultivated a high-yield salt-resistant rice variety that boasts an output of six tonnes per hectare.

In an experimental program, two professors from Hainan University and additional researchers from the Hunan Provincial Academy of Agricultural Sciences planted 18 salt-resistant varieties on 3 mu (0.2 hectares) of saline-alkali land along the sea coast in the city of Yancheng in eastern Jiangsu province this year.

After harvesting in October, one variety has proved to have similar output as varieties growing on normal farmland, said Lin Qifeng, one of the professors from Hainan University.

The progress marks a big breakthrough in the application stage as the varieties were planted in real saline-alkali soils rather than in labs, Lin said.

The professor said they will expand the experimental plantation to 100 mu in Yancheng in 2014 to further evaluate the performance of the salt-resistant varieties.

Yancheng currently has 410,000 hectares of coastal marsh, but saline-alkali land is expanding by 2,000 hectares per year.

If it proves successful in further tests and is approved by agricultural authorities, the high-yield salt-resistant variety could mean enormous economic benefits by helping the world's most populous nation cultivate its vast idle saline-alkali land, he said.

Cultivation, together with the use of rice straw and other organic fertilizers, could help improve soil conditions in the long term, said Li Guanyi, another professor with Hainan University.

China has some 13.3 million hectares of saline-alkali soils with the potential to be cultivated, equivalent to one tenth of the country's total farmland, according to data from the Chinese Academy of Sciences.

Wang Cailin, chief scientist of the rice breeding program in Jiangsu, said more than one quarter of the world's land is saline-alkali soil and another 20 percent of farmland is at risk of salination.

Traditional methods of desalination, such as soil replacement and watering down the salt, are less efficient and also costly, while the research progress on salt-resistant plants points to promising new prospects.

The professors inserted a salt-resistant gene from a wild plant into a normal rice variety six years ago. After five years of screening, they have obtained 18 salt-resistant rice varieties.

The two began to dedicate themselves to research on the development of salt-resistant varieties as early as 1992. They managed to cultivate salt-resistant vegetables, including tomatoes, eggplant, cowpeas and pepper, years later in the late 1990s.

Scientists in other countries, including the United States, have also developed salt-resistant varieties such as barley, wheat, sorghum and tomatoes. However, most saline-alkali soil exploitation worldwide focuses on landscape greening rather than the cultivation of crops and vegetables.