China's farmers will speed up cultivation of new super rice varieties in the next 15 years to raise yields to 13.5 tons a hectare as early as possible.

Minister of Agriculture Du Qinglin said China's agricultural scientists and researchers had an important mission in the next 15 years to maintain the country's lead in the development of super rice, hybrid high-yield rice strains.

Du told a national conference on agricultural science and technology in Beijing that China had made a great breakthrough with the super rice that can produce up to 12 tons per hectare.

After four years of trial crops, a variety named "State Rice No.6" was developed with an average yield 12.07 tons per hectare in east China's Zhejiang Province, with a record yield of 12.37 tons per hectare.

Although State Rice No.6 was yet to undergo a national evaluation, its qualities had been recognized by many seed companies, said Zhai Huqu, president of the Chinese Academy of Agricultural Sciences.

The China National Rice Research Institute last year earned a record 10 million yuan (US$1.21 million) from licensing the production of State Rice No.6.

China faces a challenge in maintaining a secure food supply given a growing population, shrinking croplands and scarce water resources.

The government started the "super rice" project in 1996 to improve the production and quality of rice, the staple food of more than 60 percent of its population and accounting for 40 percent of the country's total grain consumption.

China's total rice output fell from 1999 to 2003, along with a drop in the per-hectare yield.

Under a Ministry of Agriculture plan, by the end of 2010, the country will sow 30 percent of the total rice acreage with 20 major super rice varieties.

National grain output reached 484.01 million tons in 2005, up 3.1 percent from the previous year, but China is a grain importer.

The government aims to raise annual production to 500 million tons by 2010, a key target in the drive to build a new socialist countryside.

A stable grain output was crucial to food security, farmers incomes, and global demand-and-supply capacity, experts said.