[ RadSafe ] NYT Article: Useful Mutants, Bred With Radiation
John Jacobus
crispy_bird at yahoo.com
Fri Aug 31 21:54:08 CDT 2007
Found at
http://www.nytimes.com/2007/08/28/science/28crop.html?ex=1188964800&en=06723e3fa2418176&ei=5070&emc=eta1
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August 28, 2007
Useful Mutants, Bred With Radiation
By WILLIAM J. BROAD
VIENNA Pierre Lagoda pulled a small container from
his pocket and spilled the contents onto his desk.
Four tiny dice rolled to a stop.
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.
In the early 1970s, Dr. Rutger, then in Davis, Calif.,
fired gamma rays at rice. He and his colleagues found
a semi-dwarf mutant that gave much higher yields,
partly because it produced more grain. Its short size
also meant it fell over less often, reducing spoilage.
Known as Calrose 76, it was released publicly in 1976.
Today, Dr. Rutger said, about half the rice grown in
California derives from this dwarf. Now retired in
Woodland, Calif., he lives just a few miles from where
the descendants grow, he said.
A similar story unfolded in Texas. In 1929, farmers
stumbled on the Ruby Red grapefruit, a natural mutant.
Its flesh eventually faded to pink, however, and
scientists fired radiation to produce mutants of
deeper color Star Ruby, released in 1971, and Rio
Red, released in 1985. The mutant offspring now
account for about 75 percent of all grapefruit grown
in Texas.
Though the innovations began in the United States, the
method is now used mostly overseas, with Asia and
Europe the leading regions. Experts cited two main
reasons: domestic plant researchers over the decades
have already made many, perhaps most of the easiest
improvements that can be achieved with radiation, and
they now focus on highly popular fields like gene
splicing.
Most scientists here would say its pretty
primitive, Norman T. Uphoff, a professor of
government and international agriculture at Cornell
University, said of the method. Its like being in a
huge room with a flashlight.
But the flashlight is cheap, which has aided its
international spread.
Today, the process usually begins with cobalt-60, a
highly radioactive material used in industrial
radiography and medical radiotherapy. Its gamma rays,
more energetic than X-rays, can travel many yards
through the air and penetrate lead.
Understandably, the exposure facilities for radiation
breeding have layers of shielding. Scientists run
small machines the size of water heaters that zap
containers full of seeds, greenhouses that expose
young plants and special fields that radiate row upon
row of mature plants. In Japan, one circular field is
more than 650 feet wide. A shielding dike some 28 feet
high rises around its perimeter.
Dr. Lagoda said a rust fungus threatened the Japanese
pear, a cross between pears and apples. But one
irradiated tree had a branch that showed resistance.
He said the Japanese cloned it, successfully started a
new crop and with the financial rewards paid for 30
years of research.
The payoff was even bigger in Europe, where scientists
fired gamma rays at barley to produce Golden Promise,
a mutant variety with high yields and improved
malting. After its debut in 1967, brewers in Ireland
and Britain made it into premium beer and whiskey. It
still finds wide use.
The secret, reads a recent advertisement for a
single malt Scotch whiskey costing $49.99 a bottle, is
the continued use of finest Golden Promise barley and
the insistence on oak sherry casks from Spain.
The atomic agency in Vienna has promoted the method
since 1964 in outreach programs with the Food and
Agriculture Organization of the United Nations, in
Rome.
Starting roughly a decade ago, for instance, the
atomic agency helped scientists fight a virus that was
killing cocoa trees in Ghana, which produces about 15
percent of the worlds chocolate. The virus was
killing and crippling millions of trees.
In the city of Accra on the Atlantic coast, at the
laboratories of the Ghana Atomic Energy Commission,
the scientists exposed cocoa plant buds to gamma rays.
The mutants included one that endowed its offspring
with better resistance to the killer virus.
The scientists planted the resistant variety on 25
farms across Ghana with no evidence of a resurgence,
M. R. Appaih, executive director of the Cocoa Research
Institute of Ghana, told the agency.
The atomic agency had similar success in the Peruvian
Andes, where some three million people live on
subsistence farming. The region, nearly two miles
high, has extremely harsh weather. But nine new
varieties of barley improved harvests to the point
that farmers had surplus crops to sell.
In 2006, Prof. Gomes Pando won the Peruvian prize for
Good Government Practices for her work on the
radiation mutants.
In Vietnam, the agency has worked closely with local
scientists to improve production of rice, a crop that
accounts for nearly 70 percent of the publics food
energy.
One mutant had yields up to four times higher than its
parent and grew well in acidic and saline soils,
allowing farmers to use it in coastal regions,
including the Mekong Delta.
Last year, a team of 10 Vietnamese scientists wrote in
an agency journal, Plant Mutation Reports, that the
nation had sown the new varieties across more than one
million hectares, or 3,860 square miles. The new
varieties, they added, have already produced
remarkable economic and social impacts, contributing
to poverty alleviation in some provinces.
Dr. Lagoda said that radiation breeding, though an old
technology, was undergoing rapid growth. New methods
that speed up the identification of mutants are making
radiation breeding even more popular, he said.
Now it becomes interesting again, he said of the
method. Its not a panacea. Its not the solution.
But its a very efficient tool that helps us reduce
the breeding time.
Spreading the secret, Dr. Lagoda added as he played
with his tiny dice, is very gratifying because we
really, really help people.
+++++++++++++++++++
"All of the old-timers knew that subprime mortgages were what we called neutron loans -- they killed the people and left the houses. . . .
"LOUIS S. BARNES, a partner at Boulder West, a mortgage banking firm.
-- John
John Jacobus, MS
Certified Health Physicist
e-mail: crispy_bird at yahoo.com
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