T. V. Padma, SciDev.Net

Nine varieties of rice that survived in fields flooded by seawater when last year's Indian Ocean tsunami struck are the subject of a hunt for salt-tolerance genes.

Indian scientists — from the M. S. Swaminathan Research Foundation in Chennai, the Tamil Nadu Agriculture University and the Indian Agriculture Research Institute in Delhi — observed the plants growing in waterlogged fields in Tamil Nadu state.

Researchers now aim to identify genes that helped the rice plants survive the salty conditions, and which could be used to develop improved salt-tolerant varieties.

When the tsunami struck on 26 December last year, seawater intruded three kilometres into the Indian state of Tamil Nadu, depositing 30-centimetre thick sediments and damaging rice, groundnut, onion and other crops.

"We found a series of lines of rice standing when all others had died," said M. S. Swaminathan, a crop scientist and chair of the foundation that bears his name, in a 27 June press conference.

The surviving rice plants are tall, have red kernels and low yields. They are known by local names such as kundhali, kallurundai and soorakuvai.  

Swaminathan says these native varieties can serve as an important source of genetic material to help rehabilitate areas struck by similar coastal disasters.

Their seeds have been collected and are being multiplied so the researchers can conduct trials in experimental plots, he told SciDev.Net.

The scientists plan to artificially create conditions where soils are inundated with seawater and study the plants' survival.

In laboratories, the scientists will look at whether and how much the plants are genetically distinct from other varieties that do not tolerate salt, and whether they use different genes to help them survive in salty conditions.

Salt-tolerant varieties of rice have already been used to restore agriculture to lands that were destroyed by the tsunami (see Tsunami-hit farmers to grow salt-tolerant rice).

They are also the focus of research to help coastal farmers adapt to climate change by providing them with rice plants that can cope with the effects of rising sea levels.