LOS BANOS (Philippines) • Rice-growing techniques learnt through thousands of years of trial and error are about to be turbocharged with DNA technology in a breakthrough hailed by scientists as a potential second "green revolution".

Over the next few years, farmers are expected to have new genome sequencing technology at their disposal, helping to offset a myriad of problems that threaten to curtail production of the grain that feeds half of humanity.

Drawing on a massive bank of varieties stored in the Philippines and state-of-the-art Chinese technology, scientists recently completed the DNA sequencing of more than 3,000 of the world's most significant types of rice.

With the huge pool of data unlocked, better rice varieties may be developed and passed on to farmers' hands in less than three years, compared with 12 without the guidance of DNA sequencing.

"This will be a big help to strengthen food security for rice eaters," said Dr Kenneth McNally, an American biochemist at the Philippines-based International Rice Research Institute (IRRI).

A multinational team undertook the four-year project with the DNA decoding primarily done in China by BGI, the world's biggest genome sequencing firm.

Leaf tissue from the samples were ground by Dr McNally's team at a laboratory in Los Banos, near Manila's southern outskirts, before being shipped for sequencing.

A non-profit research outfit founded in 1960, IRRI works with governments to develop advanced varieties of the grain.

Farmers and breeders will require the new DNA tools, which scientists take pains to say is not genetic modification, because of the increasingly stressful conditions for rice growing expected in the 21st century.

While there will be many more millions to feed, there is expected to be less land available for planting as farms are converted for urban development, destroyed by rising sea levels or converted to other crops.

Floods, droughts and storms are also expected to worsen with climate change.

And fresh water, which is vital for growing rice, is expected to become an increasingly scarce commodity in many parts of the world.

The scientists behind the project hope that it will lead to a second "green revolution".

The first began in the 1960s as the development of higher-yielding varieties of wheat and rice was credited with preventing massive global food shortages.

AGENCE FRANCE-PRESSE