A little radiation could lift food production

The Joint FAO/IAEA Division helps develop crop varieties that thrive in an environment suffering from the consequences of climate change
(V. Schoehl/IAEA)

Gloomy predictions of less food in Africa and Asia in another decade as a result of climate change and low investment can be turned around with a little help from nuclear science, says the International Atomic Energy Agency (IAEA).

It's just a matter of exposing seeds of staple grains to radiation to induce desired changes in plants, making them resistant to drought, to certain diseases, or [giving them] an ability to thrive in saline soil, said Chikelu Mba, Head of the Plant Breeding Unit of Agriculture and Biotechnology Laboratory at the IAEA. The laboratory is run jointly with the UN Food and Agriculture Organisation (FAO).

If countries cannot afford access to "radiation breeding", the IAEA will do it for them at no charge. So why has it not solved the world's food crisis?  "Few people are aware of these facilities," said Mba.

In a year when food shortages have combined with rising demand to create a new global food crisis, the IAEA and FAO were "calling for a revival of interest in this safe, cost-effective and proven technology, especially for producing crops that are adapted to the consequences of the burgeoning climate change and variations such as drought, flooding, salt pollution and extreme weather conditions," Mba said.

"Countries in sub-Saharan Africa, with more vulnerable agricultural systems, stand to benefit most from the routine integration of radiation-induced mutations in their national crop improvement activities. It is our opinion that there is no reason why the results of the use of this technology in Asia and Europe couldn't easily be replicated in sub-Saharan Africa."

Fiddling with the blueprint

All species have a blueprint, called the genome, which determines a variety of actual and potential characteristics; for instance in plants it controls height, yield, susceptibility or resistance to disease, and many others. But only a few of the many possibilities get the opportunity to develop. A plant can adapt to different conditions through a process of spontaneous mutation and natural selection.

It was the survival of certain edible plants in adverse conditions that first attracted hunter-gatherers thousands of years ago, said an IAEA press release. "They selected the robust, easy-to-harvest wild grains, consumed the crop and saved the seeds for planting the following year. Modern plant breeding was born."

Plant breeding can be done in several ways. A breeder looking for pest resistance, for example, might find the characteristic in a wild variety that has poor quality and yield. This will be crossed with a plant that has good quality and yield, and any offspring with the desired traits will then be selected and propagated. The process can take seven to ten years, whereas spontaneous mutation occurs naturally and can take very much longer.

"We call spontaneous mutation the motor of evolution. If we could live millions of years, and survey billions of hectares of land with 100 percent precision, we would find variants with all of the traits we're looking for, but which have mutated naturally," said Pierre Lagoda, Head of the FAO/IAEA Joint Division's Plant Breeding and Genetics Section.


"But we can't wait millions of years to find the plants that are necessary now if we want to feed the world. So, with induced mutation we are actively speeding up the process."

In induced mutation, scientists apply mutagens — for example, gamma rays or chemicals — to accelerate the process. Unlike genetic modification, which introduces new material into a plant's genetic makeup, induced mutation accelerates the natural process of spontaneous changes occurring in plants, the IAEA press release explained.

Exposure to radiation makes minute changes in a plant's blueprint, creating a variant that is different from the parent plant. A number of variants are produced in the search for desired traits. Those that seem promising are selected and given to plant breeders, who work to incorporate that quality, perhaps by cross-breeding, into unmodified plants.

''If countries cannot afford access to "radiation breeding", the IAEA will do it for them at no charge''

Induced mutation also provides a solution to bottlenecks in classical plant breeding, in which hybrids - the product of crosses - are only as good as the source parents.

"With many decades of monocultures, the variations amongst candidate parents have become very narrow. This endangers food security, as resistance to yet latent biotypes of pests and diseases and extreme weather conditions may have become severely eroded. Additionally, it is becoming increasingly difficult to prospect for plant genetic resources across national boundaries," the IAEA noted.

Millions of variants are produced by induced mutation, and breeders then have to screen for the desired traits and crossbreed. Nature can help this process: if improved varieties are planted in a diseased field, the survivors will be the resistant ones.

Because fewer pesticides are needed for disease- and insect-resistant crops, they are more environmentally friendly and reduce the production costs of poor farmers.

Still some resistance

Radiation breeding faces some resistance, and there has been public concern over words like "radiation" and "mutation". "I understand that people are suspicious of these technologies, but in our case it's important to understand that in plant breeding we're not producing anything that's not produced by nature itself," said Lagoda. "There is no residual radiation left in a plant after mutation induction."

The IAEA has been working on radiation breeding for the past 44 years, said Mba, and has had successes. In the mid-1990s the IAEA and counterparts like the Cuu Long Delta Rice Research Institute in Vietnam had an important breakthrough with the introduction of the "VND series", a variety of rice that was shorter, which prevented the crop from falling over, and also made it easier to harvest.


The latest variety, VND95-20, is now grown on 30 percent of the Mekong Delta's one million hectares of rice-growing area, and is the most widely used rice in Vietnam. It thrives in the delta's saline conditions and has good resistance to a major insect pest, the brown plant hopper. 

Another variety in the series, VND99-3, can be harvested three times a year, and within 100 days of planting the seeds, greatly improving food security for Vietnam's 84 million people. 

IAEA scientists are collaborating with plant breeders in several African countries, using nuclear techniques to improve the safety of cassava and enhance its nutritional content, yield and resistance to disease. 


This article was produced by IRIN News while it was part of the United Nations Office for the Coordination of Humanitarian Affairs. Please send queries on copyright or liability to the UN. For more information: https://shop.un.org/rights-permissions

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