Together with the International Rice Research Institute (IRRI), the university has been working on aerobic rice that is grown like an upland crop such as wheat and corn in soil which is not flooded or paddled.

Aerobic rice requires 50-70 percent less water, although its yields are about 30 percent less than hybrid rice -- a strain that brought about the Green Revolution in the 1960s, Wang told Reuters on the sidelines of a workshop in Beijing.

"Our objective is to help farmers cope with decreasing water availability. Water is getting scarce," said Bas Bouman, a senior scientist at IRRI.

IRRI said aerobic rice could be considered a mature technology in temperate countries such as northern China or Brazil, where breeding programmes since the 1980s have resulted in the release of several high-yielding aerobic rice varieties.

In tropical countries such as Thailand, the largest rice exporter, India and Philippines, aerobic rice systems are still in the research and development phase, said IRRI in a report.

SERIOUS DAMAGE

Wang said the water shortage was already taking its toll on lowland rice in China, with the average yield dropping to 6 tonnes per hectare from 7.5 tonnes.

About a third of 4.6 million ha planted with lowland rice in northern China faced water shortages, while drought led to damage to lowland rice in the south, the country's major rice areas, he said.

In some areas in China's central province of Hubei, water supply for irrigating rice shank to 30 percent of the level in the 1960s due to sprawling cities and industries, Bouman added.

"In Yangtze River areas, where there is plenty of water, more water are used as cities and industries grow, but not for agriculture," said Bouman.

With Beijing handing out subsidies to grain farmers, prompted by surges in prices in 2003, Chinese rice output has increased each year to reach 186 million tonnes this year, up from the trough of 160 million tonnes in 2003.

However, Wang said China would need to produce about 20 percent more rice by 2030 to feed its increasing population, while limited irrigation infrastructure coupled with declining freshwater resources and farmland, limit potential for flooded rice in China.

Aerobic rice is also able to withstand flooding, prevalent in Auhui and areas along the Yellow River in the summer months and that can damage or destroy alternative summer crops such as maize or soybeans.