Asia races to find drought-resistant rice

Success of a flood-proof rice variety gives researchers hope as climate stress worsens
The monsoon rains are essential for growing rice in India, but their inconsistency affects production © AFP

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Half of all people in the world, mostly those living in Asia, depend on rice as a staple food, eaten up to three times a day.

But, compared with other food grains, global production of rice has always been finely balanced against demand, with little surplus traded on the market. As Asian weather patterns, especially the distribution of monsoon rains, become more erratic due to climate change, policymakers are concerned about the stability of global rice production and the long-term welfare of rice farmers and consumers.

The International Rice Research Institute (IRRI), based in the Philippines, is working to develop seeds for new rice varieties that will be able to resist the kind of climate stresses, such as floods, drought and soil salinity, that are expected to become more frequent due to global warming.

Flood-resistant rice strains, whose development by the IRRI started in the late 1970s, are already paying off in India, Bangladesh and Nepal, where millions of farmers now grow rice varieties that can survive total submergence in water for between 14 and 20 days. Previously popular high-yielding rice varieties would be destroyed after just four or five days under water.

Uma Shankar Singh, who leads the IRRI mission in India and Nepal, says researchers are also making progress in developing drought-resistant rice varieties, which could be available to farmers within a few years.

“The world talks about climate change adaptation, but we hardly have anything to show on the ground,” says Mr Singh, the regional co-ordinator for IRRI’s Stress Tolerant Rice for Africa and South Asia (STRASA) project, which is funded by the Bill & Melinda Gates Foundation. “This is a direct example.”

Climatic stress is acute in South Asia, home to about 37 per cent of the world’s rice-growing area and prone to floods, drought, salinity, or some combination of those problems.

Floods are increasingly frequent, but so are periods of severe dryness during monsoon seasons. Many days can go by between rains, a contrast to the predictable daily downpours that older farmers say they remember. “It’s not that the total amount of rainfall has changed,” says Mr Singh. “But its uneven distribution is creating both flood and drought.”

Rice-consuming countries saw the impact of disruptions in the global supply of rice in 2008, when Bangladesh, the Philippines and parts of west Africa all suffered food riots triggered by spiralling global rice prices that had jumped 300 per cent, from $300 to $1,200 per ton, over four months.

The price spike had several causes, one of which was the imposition of export restrictions by India. Another factor was panic buying by several large rice-consuming countries including Bangladesh, which was facing a rice shortage after severe flooding in the summer of 2007 caused damage to 2.2m acres of cropland.

In fact, global rice stocks were not very low at the time and both the panic and prices subsided after a few months. But it was a warning about the kind of global ripple effect that could ensue should a shortfall occur. “There is not much surplus rice for the international trade,” says Mr Singh. “If there is any serious flood in China or India, no one can supply the rice. What rice is produced is consumed; the situation is tight.”

IRRI’s plan to develop rice that can tolerate extreme weather relies on a bank of seeds from around 127,000 traditionally cultivated rice varieties, known as “landraces”, as well as on wild rice collected from around the world.

Many of the traditional varieties are disdained by contemporary farmers due to low-yields or poor grain quality. But, having adapted over centuries in various climactic conditions, some have evolved to be able to withstand local climactic stresses.

Abdelbagi Ismail, head of the STRASA project, describes IRRI’s seed bank as “a treasure collected from all over the world, adding: “It has all the diversity and all the traits we look for in rice.”

For decades, IRRI scientists had searched for rice varieties that could combine the genes required for flood tolerance with those of other high-yield varieties developed during the Green Revolution of the 1960s, which transformed wheat and rice farming in irrigated parts of north India.

Then, in 2002, researchers identified the precise gene in a landrace from eastern India that allowed it to survive a submergence of up to 20 days. By 2006, IRRI had combined that gene with a popular high-yielding rice variety and had provided 200 grammes of the seed to the Indian government’s own rice research institute. By 2013, nearly 5m Indian farmers had some fields planted with this flood-tolerant rice, covering about 1.7 to 2m hectares in total.

The institute is now using similar methods in its effort to develop drought-resistant rice and the process has been accelerated by recent developments in genetic mapping. “We are now testing lines that are both drought and flood tolerant,” Mr Singh says. “We must make a variety that can tolerate any condition.”

The challenge is not merely scientific, but also political and logistical. South Asian governments must approve new seed varieties, then distribute these seeds to farmers, who must in turn be educated about their benefits and correct use.

In the past, regional governments have subjected new IRRI seed varieties to years of additional testing before approving them for use by their own farmers. But India has shortened the testing period and in 2014 the governments of India, Nepal and Bangladesh agreed that seed varieties approved for use in one country will be automatically approved for use in all.

“We want these new varieties to reach the farmers as fast as possible,” Mr Singh said. “The biggest challenge we are facing is making seeds locally available to farmers in remote area and taking information about these new varieties to the farmers. We have to gear up the whole system to do this.”

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