With rice production in Vietnam's fertile Mekong delta threatened by salt water from rising sea levels, researchers say they're turning to genetics for help.

Scientists at the International Rice Research Institute are working with Vietnamese counterparts in experiments in the Philippines to develop a variety of rice that can withstand submergence for over two weeks and also resist increased salinity.

An existing flood-tolerant variety, dubbed "scuba rice," already offers half the solution, researchers said.

"IRRI is experimenting to find a rice variety to deal with both problems," Bjorn Ole Sander, a scientist at the world's leading non-governmental research center on rice, told Inter Press Service.

"Even if we have rice crops that are tolerant to floods they can die because of salinity."

The search for a salinity-tolerant variety that could be cross-bred with scuba rice is daunting, he said.

"It will take at least four years to find a rice variety that will be tolerant to both salinity and flooding," he said.

With climate change and global warming the search for a solution is vital, he said, noting that salt water from the South China Sea now spreads 25 miles into the Mekong delta, unlike the 6 miles inland the sea tides reached 30 years ago.

"That would be the answer to the problems faced in the Mekong Delta from flooding and salinity from the rising sea tides."

Researchers in Britain and Japan also are working on developing saline-resistant rice.