Useful Mutants, Bred With Radiation

VIENNA — Pierre Lagoda pulled a small container from his pocket and spilled the contents onto his desk. Four tiny dice rolled to a stop.

Pierre Lagoda, the head of plant breeding and genetics at the International Atomic Energy Agency, showing mutated plants at a greenhouse in Austria.

Thats what nature does, Dr. Lagoda said. The random results of the dice, he explained, illustrate how spontaneous mutations create the genetic diversity that drives evolution and selective breeding.

He rolled the dice again. This time, he was mimicking what he and his colleagues have been doing quietly around the globe for more than a half-century — using radiation to scramble the genetic material in crops, a process that has produced valuable mutants like red grapefruit, disease-resistant cocoa and premium barley for Scotch whiskey.

Im doing the same thing, he said, still toying with the dice. Im not doing anything different from what nature does. Im not using anything that was not in the genetic material itself.

Dr. Lagoda, the head of plant breeding and genetics at the International Atomic Energy Agency, prides himself on being a good salesman. It can be a tough act, however, given wide public fears about the dangers of radiation and the risks of genetically manipulated food. His work combines both fields but has nonetheless managed to thrive.

The process leaves no residual radiation or other obvious marks of human intervention. It simply creates offspring that exhibit new characteristics.

Though poorly known, radiation breeding has produced thousands of useful mutants and a sizable fraction of the worlds crops, Dr. Lagoda said, including varieties of rice, wheat, barley, pears, peas, cotton, peppermint, sunflowers, peanuts, grapefruit, sesame, bananas, cassava and sorghum. The mutant wheat is used for bread and pasta and the mutant barley for beer and fine whiskey.

The mutations can improve yield, quality, taste, size and resistance to disease and can help plants adapt to diverse climates and conditions.

Dr. Lagoda takes pains to distinguish the little-known radiation work from the contentious field of genetically modified crops, sometimes disparaged as Frankenfood. That practice can splice foreign genetic material into plants, creating exotic varieties grown widely in the United States but often feared and rejected in Europe. By contrast, radiation breeding has made few enemies.

Spontaneous mutations are the motor of evolution, Dr. Lagoda said. We are mimicking nature in this. Were concentrating time and space for the breeder so he can do the job in his lifetime. We concentrate how often mutants appear — going through 10,000 to one million — to select just the right one.

Radiation breeding is widely used in the developing world, thanks largely to the atomic agencys efforts. Beneficiaries have included Bangladesh, Brazil, China, Costa Rica, Egypt, Ghana, India, Indonesia, Japan, Kenya, Nigeria, Pakistan, Peru, Sri Lanka, Sudan, Thailand and Vietnam.

Politically, the method is one of many quid pro quos the agency, an arm of the United Nations in Vienna, offers client states. Its own agenda is to inspect ostensibly peaceful atomic installations in an effort to find and deter secret work on nuclear weapons.

Plant scientists say radiation breeding could play an important role in the future. By promoting crop flexibility, it could help feed billions of added mouths despite shrinking land and water, rising oil and fertilizer costs, increasing soil exhaustion, growing resistance of insects to pesticides and looming climate change. Globally, food prices are already rising fast.

Its not going to solve the world food crisis, said J. Neil Rutger, former director of the Dale Bumpers National Rice Research Center in Stuttgart, Ark. But it will help. Modern plant breeders are using every tool they can get.

The method was discovered some 80 years ago when Lewis J. Stadler of the University of Missouri used X-rays to zap barley seeds. The resulting plants were white, yellow, pale yellow and some had white stripes — nothing of any practical value.

But the potential was clear. Soon, by exposing large numbers of seeds and young plants, scientists produced many more mutations and found a few hidden beneficial ones. Peanuts got tougher hulls. Barley, oats and wheat got better yields. Black currants grew.

The process worked because the radiation had randomly mixed up the genetic material of the plants. The scientists could control the intensity of the radiation and thus the extent of the disturbance, but not the outcome. To know the repercussions, they had to plant the radiated material, let it grow and examine the results. Often, the gene scrambling killed the seeds and plants, or left them with odd mutations. But in a few instances, the process made beneficial traits.

In the 1950s and 1960s, the United States government promoted the method as part of its atoms for peace program and had notable successes. In 1960, disease heavily damaged the bean crop in Michigan — except for a promising new variety that had been made by radiation breeding. It and its offspring quickly replaced the old bean.

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