''Submergence-tolerant rice varieties are classic examples of adaptation to climate change,'' says Uma Shankar Singh, a rice scientist with the Philippines-based International Rice Research Institute (IRRI).

Singh, who is currently in India, told IPS that the IRRI plans to transfer its highly successful SUB1 (short for submergence1) flood-tolerant gene to popular rice varieties across Asia to confer ability to withstand total submersion for more than two weeks.

''IRRI will transfer the SUB1 gene to most rice varieties with help from national research systems since rice crops may, thanks to climate change, increasingly encounter floods,'' Singh said.

Singh said that where IRRI only provided field-tested rice lines tolerant to flooding it has now begun to proactively assist government agencies and private seed companies to propagate and distribute seeds to farmers. Field testing a new rice variety may take four to five years before release and another two to three years before it reaches farmers.

After modifying the popular Indian rice 'Swarna' with the 'SUB1' gene to produce the 'Swarna-Sub1', IRRI scientists had the new variety released in August 2009 and are gratified to see it spread so fast that it may completely replace the original variety in flood-prone areas.

"We encouraged state governments to distribute the seeds for large-scale multiplication, and disseminate the seeds directly to farmers,'' Singh said. A Sep. 14 IRRI release quoted David Mackill, a top IRRI scientist who helped isolate the SUB1 gene as saying that the new variety was ''resilient to flooding for up to 17 days while retaining the desirable traits of the original variety.''

Mackill and other IRRI scientists argue in favour of rapid release of the Swarna Sub1 and vow that rice varieties into which the Sub1 gene has been inserted will not have problems -- such as susceptibility to diseases or insects -- that the originals do not suffer from.

With that confidence the IRRI has, since August 2009, helped distribute 'Swarna-Sub1' seeds to 100,000 farmers in India. It is now being grown over 12 million of the 44 million hectares of paddy in this country.

Singh said Bangladesh, a deltaic country, seriously threatened by climate change, is moving faster than India in taking advantage of the Swarna-Sub1 variety, which has also been released in the Philippines and Indonesia.

In 2009 the Bangladesh University of Engineering and Technology (BUET) and the South Asian Association of Regional Cooperation (SAARC) Meteorological Research Centre used computer simulations incorporating data on genetic characteristics, soil, water and weather, to show that rice production in the country could drop to half by 2070.

According to IRRI estimates farmers in Bangladesh and India already lose up to four million tons of rice crop annually to flooding. Rice thrives in standing water but most varieties perish within a week of being submerged.

Not everyone is happy with technology that involves artificially inserting genes into a staple like rice and quickly releasing it for mass application. ''You may know what you are getting by inserting the SUB1 gene into a rice variety but you cannot possibly know what traits you are losing, except over a number of years,'' says food security specialist Devinder Sharma.

Sharma who runs the independent, New Delhi-based Forum for Biotechnology and Food Security said there are thousands of varieties of rice, and each has traits suited to a specific geographical area.

''For example, salt water ingress following the 2004 Asian tsunami revealed naturally growing rice varieties tolerant to salinity,'' said Sharma. Increasing salinity in coastal areas is an expected consequence of the sea level rising as polar ice shields and glaciers melt from global warming.

Flood resistance is not the only trait that is desirable, agrees Suman Sahai, agricultural scientist and founder of 'Gene Campaign' that fosters community- run seed banks in the central Indian state of Jharkhand that preserve some 2,000 traditional rice lines.

Sahai believes that long-term food security lies in preserving crop biodiversity and points to traditional varieties which are suitable for different soil types, topography, temperature and water availability.

''If coastal areas get submerged then crop varieties will need to develop tolerance not only to water-logging but also to salinity,'' says Sahai. Similarly, as inland areas become drier from climate change it will be prudent to develop drought tolerant varieties, says Sahai.

She adds that changes in weather patterns could result in proliferation of new diseases or insect pests that call for varieties resistant to these threats as well. ''All this means ready access to the required genes preserved through maintaining biodiversity.''

Since agriculture constitutes a large fraction of the GDP in South Asian countries, even a small percentage loss in agricultural productivity through climate change may result in proportionately larger income losses as compared to industrialised countries.

According to Sahai the biggest blow to food production from climate change will be to multiple cropping zones especially in the states of Punjab, Haryana and western Uttar Pradesh which now give India its comfortable surpluses. (END)

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