Rice is the staple food for more than three billion people

Most rice plants die within a week of being underwater, but the researchers hope the new gene will offer greater protection to the world's rice harvest.

Farmers in south-east Asia lose an estimated £524m ($1bn) each year from rice crops being destroyed by flooding.

The findings have been published in the science journal Nature.

The team from the University of California, Davis, US, and the International Rice Research Institute (IRRI) based in the Philippines says the gene, called Sub1A-1, will give the plants greater protection against damaging flooding.

They say it will also offer farmers greater crop protection, especially those who live in vulnerable areas.

Flood risks

Although rice production has doubled over the past 40 years, demand is continuing to grow. The crop is the staple food for more than three billion people around the globe.

Attempts to breed that tolerance into commercially viable rice failed to generate successful varieties

Dr David Mackill, paper's co-author

Many rice growing regions in southern Asia are located in low-lying areas that are at risk from flooding during the monsoon season.

Plants submerged in water for longer than a few days are deprived of carbon dioxide and soon wither and die.

Dr David Mackill, from the International Rice Research Institute and one of the paper's authors, said scientists had been trying for half a century to develop a water resistant crop.

"Several traditional rice varieties have exhibited a greater tolerance to submergence, but attempts to breed that tolerance into commercially viable rice failed to generate successful varieties," he explained.

Another member of the team, Dr Pamela Ronald from the University of California, Davis, added: "Our research team anticipates that these newly developed rice varieties will help ensure a more dependable food supply for poor farmers and their families."

Takuji Sasaki, from Japan's National Institute of Agrobiological Sciences, said the researchers had succeeded where others had failed.

"The particular impact of this study lies in [the] accurate and effective introduction of Sub1A-1 into local rice varieties subject to seasonal flooding."

The team members said that they were confident that "even more important" discoveries were in the pipeline.