There is good news for rice farmers in the flood-prone Indian states and also in Bangladesh. Their paddy fields, submerged even for 15 days in flood waters will have a second life, if they plant the new rice variety, ‘Swarna-Sub1’.
The ‘Sub1’ is the gene that empowers paddy to lie dormant during floods and rise up more vigorously when the water recedes. Scientists of the International Rice Research Institute (IRRI) in the Philippines, created the new rice by using the gene that gives flood-tolerance quality to a low-yielding variety in Orissa, the homeland of rice. It took decades of research and trials for them to transfer the gene to high-yielding varieties like ‘Swarna’ through marker assisted selection (MAS), a non-transgenic process. Its official release for commercial cultivation is expected next year.
With the ‘Sub1’ concept well and truly proved in the labs and trial plots, IRRI sent seeds of popular variety ‘Swarna’ now developed to ‘Swarna Sub1’ to national organisations in South Asia, including the Bangladesh Rice Research Institute (BRRI), and the Central Rice Research Institute (CRRI) in Orissa, and Narendra Dev University of Agriculture and Technology in Faizabad, Uttar Pradesh, for testing and refinement. The trial results there were also extremely promising.
In November 2008, the ‘Sub1′ variety was test-planted in farmers’ fields in Bangladesh, West Bengal, UP and Orissa. Swarna Sub1 plants recovered even after 15 days of flooding while the non-Sub1 varieties perished. The results had encouraged farmers in Orissa to say “Forget Swarna! Go for Swarna-Sub1”.
According to N Shobha Rani, principal scientist at the Directorate of Rice Research, Lucknow, the new flood-proof paddy should be available for farmers by 2010. “Traditionally-bred rice must undergo testing for 3 years in all-India trials, but this has been reduced to 2 years for MAS-derived varieties. The second year of testing is in 2009. So, April 2010 is the earliest time the Sub1 varieties could be recommended by the Central Variety Release Committee for national release, she was quoted as saying in ‘Rice Today’, the official magazine of IRRI.
A quick release is also possible because plants developed through MAS are not transgenic. Therefore, the new Sub1 varieties are not subject to the regulatory testing that can delay release of transgenic products for several years. However, that release could occur on a state-basis even earlier, as in Uttar Pradesh. In February 2009, the UP seed certification committee has released the modified ‘Swarna Sub1’ variety for large-scale cultivation. IRRI is planning to take this new rice variety to the small farmers in flood-prone areas through the project ‘Stress-Tolerant Rice for Poor Farmers in Africa and South Asia’, funded by the Bill & Melinda Gates Foundation.
IRRI is also collaborating with national organisations to test Sub1 varieties in Southeast Asian countries, including Laos, Thailand, Cambodia, Indonesia, Vietnam, and the Philippines, through a project funded by Japan’s ministry of foreign affairs.
The IRRI scientists have identified how the Sub1 rice survives the floods. They say that “when submerged, rice without Sub1 gene responds by increasing the pace of its elongation in an attempt to escape the submergence. Deep water rice varieties are able to do this rapidly enough to succeed. In modern high-yielding varieties,the elongation is insufficient. If the flood lasts for more than a few days, the normal varieties expend so much energy trying-unsuccessfully-to escape that they are unable to recover. Submergence of Sub1 varieties, on the other hand, activates the Sub1 gene, which suppresses this elongation strategy, effectively shunting the rice plant into a dormant state until the floodwaters recede. The plants conserve their energy for a post-flood recovery.