Bangladesh's crop scientists find an ally to better cope with climate change

By Laura Gil

Bangladesh, whose populous and low-level delta region is expected to be severely affected by rising sea levels, is using nuclear technology to adapt to this threat. Scientists are looking for ways to protect the country’s agriculture against flood and salinity, as well as drought and changing temperatures. With support from the IAEA and the Food and Agriculture Organization of the United Nations (FAO), they are developing climate change resilient crop varieties that will help feed the country’s growing population.

“We are in constant fight. We fight salinity in our soil, extreme temperatures, drought and floods,” said Mirza Mofazzal Islam, chief scientific officer and head of the Plant Breeding Division at the Bangladesh Institute of Nuclear Agriculture (BINA). “But, for all these problems, we have a solution — at least as far as crops are concerned.”

Scientists at BINA have been developing radiation-induced plant varieties that can resist diverse climatic conditions. In the last decades, these plant varieties have helped farmers increase rice production three-fold, ensuring food security and giving this predominantly agricultural country an important economic push.

The more than 60 plant varieties the scientists can offer to farmers today have been developed through a process called plant mutation breeding (see Plant mutation breeding). These varieties of rice, lentils, chickpeas, peanuts, mustard, sesame, soybean, jute, tomato and wheat have now become popular across Bangladesh, accounting for about 8% of its crops, helping farmers produce a steady supply of these crops and improving livelihoods.

“Irradiation can be used to induce mutations in plants to produce varieties that display improved product quality, have higher yields and yield stability, greater resilience to climate change and tolerance to environmental stresses,” said Ljupcho Jankuloski, plant breeder and geneticist at the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. “The rice mutant varieties developed at BINA have helped Bangladesh increase its rice production in the last few decades.”

Salt, water, air

The Joint FAO/IAEA Division, through the IAEA technical cooperation programme, has been training scientists at BINA since the 1970s, establishing expertise and setting the stage for the development of improved varieties with climate-resilient traits. With the threat of putting 27 million people at risk by 2050, climate change is expected to take a strong toll in this part of the world. Sitting on low land and relying heavily on agriculture, the country is especially vulnerable to climate change.

“It is especially now in the face of increasingly extreme weather conditions and the need for more yields that nuclear science and technology in agriculture has become indispensable,” said Syahril Syahril, project manager at the IAEA responsible for technical cooperation with Bangladesh.

One new mutant rice variety, for example, needs less time to grow while producing more rice, in comparison to local conventional varieties. Another, resistant to salinity, is being deployed near the Bengal Bay, a one-million hectare spread of saline soil. “Before, this area could grow no crops,” Mofazzal Islam said. “Seeing that crops can thrive here gives us hope, especially because we are expecting rising sea levels and higher salinity in soil to be one of the biggest threats to our agriculture.”

Scientists have also developed rice varieties that can do better in flood-prone areas. “In general, crops can survive even when completely submerged, but only for three to four days,” Mirza Mofazzal Islam added. “But with modern breeding, the new rice varieties can live underwater for more than three weeks.” At the same time, a new rice variety developed by New Rice for Africa, or NERICA, in Uganda can thrive under drought conditions.

“We have gone from worrying about hunger to focusing on nutrition,” Mirza Mofazzal Islam said. “From food security to nutritional security. This means we are not only interested in ensuring access to food, but to healthy, nutritious food. Our aim is to be self-sufficient by 2021 with the help of these new varieties.”

The science

Plant mutation breeding

Applied since the 1930s to accelerate the process of developing and selecting new valuable agronomic traits, mutation breeding uses a plant’s own genetic make-up, mimicking the natural process of spontaneous mutation. The mutation process generates random genetic variations, resulting in mutant plants with new and useful traits.

The process consists on exposing plant seeds or plant explants to radiation, such as gamma rays or x-rays, and then planting the seeds or cultivating the plant explants in a sterile medium, which generates a plantlet. The individual plants are then screened (or phenotyped) for their traits. Individual plants with improved agronomic traits are selected and multiplied. Molecular marker-assisted breeding, often referred to as marker-assisted selection, is used to accelerate the selection of plants with desired traits, carried by genes of interest.

Plant mutation breeding does not involve gene modification, but rather uses a plant’s own genetic resources and mimics the natural process of spontaneous mutation, the motor of evolution. By using radiation, scientists can significantly shorten the time it takes to breed new and improved plant varieties.