Population pressure, climate change drive search for new rice varieties

Like many farmers in Bangladesh, Abdul Aziz from Naogaon District in northwestern Bangladesh has had to adapt his plantings to increasingly erratic weather: “Twenty years ago we had a rainy season at this time. Now we don’t even know when the seasons come…Twenty years ago we experienced five months of monsoon, now it’s only 15-20 days in two or three months.”

To adjust to the unreliable rains, local farmers for the past 20 years have been using ‘pariza’, an indigenous rice that requires less irrigation and can be harvested off-season, from May to August, between the dry season `boro’ rice and the monsoon ‘aman’ rice.

Aziz and his friends are now also using new varieties developed by the Bangladesh Rice Research Institute (BRRI) and the Philippines-based International Rice Research Institute (IRRI). They are drought-tolerant, dry season varieties - dubbed BRRI dhan 6, 28, 29 and 33 - and harvested in April.

Bangladesh is seen as one of the country’s most susceptible to climate change and is seriously affected by droughts and flooding.

With a population of 160 million, growing at about 1.4 percent per year, Bangladesh produces about 30 million tons of rice each year - 2.5 million less than it needs to feed itself. As arable land decreases by about 1 percent a year, more productive crops are urgently needed.

“The population pressure on land resources is the key driving force for the use of the new technologies,” said Mahabub Hossain, executive director of the Bangladesh Rural Advancement Committee (BRAC) and former head of IRRI’s social sciences division.

Rice race

Bangladesh’s population boom in the 1950s led to farmers cultivating two crops a year instead of one. The 1960s saw increased yields thanks to modern inputs like chemical fertilizers. IRRI, set up in 1959, sought new ways of feeding growing populations.

Photo: David Swanson/IRIN
Developing new rice varieties is key in Bangladesh

“In the 1960s, one rice variety was developed called IR8. It’s a semi-dwarf variety.

They introduced a dwarfing gene, which reduces the rice plant from tall to small,” Hossain said.

The idea was that if the plant was smaller, it could absorb more nutrients.

“They improved the yield from about four tons per hectare to 10 tons per hectare as a result of that discovery,” he said.

Since BRRI was set up in 1970, work by IRRI has been passed on to BRRI to test in Bangladesh and see which varieties make the grade.

“Increased production of rice can only be done through the development of modern rice varieties,” said Khairul Bashar, BRRI’s chief scientific officer. “Now we have three and a half, four times higher yields than in the 70s, but in the future, our population will increase again.”

Natural disasters

Bangladesh is prone to a variety of natural disasters throughout the year, meaning rice often needs to be imported to make up for losses.

“Bangladesh is affected by tidal surges, cyclones, drought, flash-flood submergence. That’s why we need to develop new varieties that can actually tolerate those situations,” Bashar added.

BRRI scientists have released three salt-tolerant varieties, two-submergence tolerant varieties, and in the pipeline are drought-tolerant and some cold-tolerant varieties.

Western Bangladesh is hardest hit by drought, while flash-flooding takes its toll in central regions, and salinity affects crops in southern coastal areas.

Developing a new variety of rice can take 4-10 years.

Among this year’s innovations are BRRI dhan 51 and 52, which were released in June and can survive 15 days underwater while also withstanding salinity.

“When it goes under water, it goes into hibernation so it doesn’t use energy and it remains dormant, so it uses that mechanism to survive,” said Mohammed Abedin, IRRI’s senior scientist and representative for Bangladesh. “What is important now is to develop varieties with multiple stress tolerances.”

Aziz, the farmer in Naogaon, said he ideally needs a high-yielding rice that can withstand extreme drought, something Hossain from BRAC says is still a little way off.

“In the area of drought, no real progress has been made. This is a major environmental problem… If we are successful, then we can make another breakthrough in increasing rice production, particularly during the monsoon season.”