History of Research at the
U.S. Department of Agriculture and Agricultural Research Service
the World's Plants
Watch a video to learn about this and other
discoveries that improve our daily lives.
Collecting and freely sharing plants and seeds that grow around the world is
one of the U.S. Department of Agriculture's longest continuous programs.
experts were predicting food shortages and famine because increasing population
would overtake our ability to grow sufficient wheat by 1931. They may have been
right--except 1898 was also the year U.S. Department of Agriculture special
agent Mark A. Carleton was sent on his first plant exploration trip to Russia.
He brought back new durum and hard red wheat varieties to grow in the United
Five years after the introduction of wheat
from Russia, wheat production in the United States exploded from 60,000 to 20
million bushels a year. Not only did the drought tolerance of these new
varieties open up the Great Plains and the Northwest for wheat growing, the
durum wheat tasted better in pasta, and the hard red wheat made better bread.
The USDA official who sent Carleton on his
1898 collecting trip would later write, "We have forgotten how poor our
bread was at the time of Carleton's trip to Russia. In truth, we were eating an
almost tasteless product, ignorant of the fact that most of Europe had a better
flavored bread with far higher nutritive qualities than ours."
One hundred years later, USDA plant exploring
and collecting, now under the direction of the Agricultural Research Service's
National Germplasm Resources Laboratory, is still a critical ingredient in
maintaining and expanding agriculture's ability to feed an ever-growing
Today's breads and pastas taste better and provide more nutrition thanks to
germplasm from other countries.
Plants, So Many Reasons
Plant exploring and collecting are essential
for agriculture because crops must be continually enhanced to overcome diseases
and pests, expand drought and temperature tolerance, adapt plants to new
growing conditions, and make them more productive, nutritious, durable, or
simply better tasting. The plants that collectors bring back often provide the
genetic material for breeding improved varieties.
"No one country or even one continent
has all of the genetic resources necessary to sustain crops at the level that
is needed today," says Allan K. Stoner, leader of the ARS germplasm
laboratory. "Conditions and needs continue to change, and collecting
genetic diversity is how you have the resources to deal with them."
Only 1 of the top 20 major world crops
originated in North America: the sunflower, which now ranks among the top 4
oilseed crops worldwide. Of course, there are many plants indigenous to North
America--including crops like strawberries, blueberries, cranberries, forage
grasses, pecans, grapes, and tepary beans--that are collected by both U.S. and
foreign plant explorers.
Interestingly, it was Russian researchers
who used U.S. sunflower germplasm to breed the varieties that started the
sunflower oil industry. "But our major crops came here from
elsewhere," says Stoner. "And when you are looking for genetic
diversity, the most important places to look are the centers of origin for
crops--that is, the places where they evolved and where people have been
cultivating them the longest.
"The traditional varieties that farmers
have been growing for centuries may not be as highly productive as current
varieties, but they can have genetic traits that are exactly what we need to
overcome a pest or disease problem," he says.
The wheat that USDA plant explorer Jack R.
Harlan and his Turkish colleague Osman Tosun collected from a field in Fakiyan
Semdinli, Turkey, in 1948 is a perfect example.
At the time the sample was taken, the wheat
looked terrible--it lodged, had no winter hardiness, and was susceptible to
leaf rust. By itself, "it was a hopelessly useless wheat but was dutifully
conserved," Harlan wrote of the wheat that was listed simply as Plant
Across the country, ARS scientists who work with wheat aim to make U.S.-grown
grain better all the time.
But 15 years
later, when U.S. wheat breeders were looking for a way to breed resistance to a
stripe rust outbreak, PI 178383 was found to have resistance to 4 races of
stripe rust, 35 races of common bunt, and 10 races of dwarf bunt--as well as
tolerance to flag smut and snow mold. Today, PI 178383 appears in the pedigree
of virtually all the wheat grown in the Pacific Northwest.
Interestingly, it may turn out that PI
178383 did not actually originate in southern Turkey. In 1986, ARS plant
explorer Calvin R. Sperling returned to Fakiyan Semdinli to collect more of PI
178383 and other possibly disease-resistant wheat.
In talking with the region's farmers,
Sperling discovered that they had migrated to the area only in their
grandfathers' time. They had come from northern Iraq and brought their wheat
along with them.
Wars and political instability have
precluded plant exploration of the farmers' earlier home, and no one knows if
the wheat can still be found. The Why of Plant Collecting
A sudden virulence in plant diseases or the
arrival of new insect pests illustrates another critical reason for having a
standing germplasm collection that reflects a crop's range of genetic
"It represents a crucial reservoir of
breeding material that can be turned to immediately for help when a crisis
strikes," Stoner says.
When wilt and blight became unusually
virulent and threatened to kill off the Virginia spinach industry in 1920, the
genes for resistance to these diseases were found in a spinach that had been
collected 20 years earlier in Manchuria by a USDA plant explorer.
The genetic contributions of the Manchurian
spinach have spread far beyond the Virginia Savory cultivar developed to meet
the original disease outbreak. Today, the genes are present in almost every
multidisease-resistant spinach grown.
"It is impossible to judge now just
what germplasm may be essential to our future," Stoner points out.
"All we can do is collect what seems to represent the diversity of a crop
and its relatives and preserve it until that day in the future when a plant
turns out to be the single most important source of some critical
geneticist Albert E. Percival has seen this disappearance of germplasm while
plant collecting in Mexico for traditional and wild varieties of cotton.
"Ancestors of the fine upland cotton
that is grown today in California were originally collected in the Acala Valley
of Mexico in 1906 and used in a breeding program at the Agricultural Experiment
Station in Texas," says Percival.
But when he went to the Acala Valley in 1984
to re-collect the original germplasm, he couldn't find any cotton at
"Local farmers told me that in the
1970s, a Mexican consortium decided they were going to try to grow cotton for
more than local use--as a commercial crop. The first year they had a bumper
harvest; the second year was not so good; the third year, boll weevils
destroyed the crop," explains Percival.
Growers decided to eradicate what was
perceived as the source of the infestation--the native cottons--which did not
solve the problem. Growing cotton in the region was abandoned.
"There wasn't much left to collect. It
would have been nice to have preserved those varieties for the future,"
says Percival. "There may have been genes for lint quality or some other
traits that we would like to breed into today's cotton. Now they may be gone
forever," he says.
Other times, it is the habitat as a whole
that is in danger.
For example, Percival is concerned about an
interesting race of cotton relatives--one with twice the customary number of
chromosomes--that exists only in a 2- to 3-kilometer stretch along the coast of
the Gulf of California in Mexico and only 200 to 300 meters from the water's
edge. "But this is exactly the area that a booming tourist industry is
developing, building new hotels," says Percival. "Who knows if these
plants will survive or disappear? Yet they could well be the source of
resistance to insects."
Today we enjoy tropical flowers from all over the world.
Following is a tiny taste of the immense
contributions made by USDA plant explorers during one of the department's
longest continuous programs. Corn, dates, sorghum, soybeans, potatoes, berries,
cereal grains, grapes, apples, sugar beets, forages, carrots, onions, tomatoes,
lemons, and apricots--even camellias and lawn grasses--have all been introduced
into the United States or improved by USDA-collected germplasm.
And this germplasm has been shared with
researchers, plant breeders, and farmers in hundreds of other countries.
Indeed, the descendants of collected plants have literally changed the face of
agriculture and gardening around the world. A few examples:
- Avocados that created a California industry
were brought back from Mexico, also in 1898.
- Rice varieties collected in Japan in 1900
established the beginnings of rice growing in Louisiana and Texas, two of the
United States' major rice-growing states today.
- A spinach collected in Manchuria in 1900
saved the Virginia spinach industry from blight and disaster in 1920.
- A spinach collected in Manchuria in 1900
saved the Virginia spinach industry from blight and disaster in 1920.
- Rootstock on which many U.S. peaches are
now grown descends from germplasm collected in the 1920s.
- A wild oat found in Israel in the 1960s had
genes that helped breeders develop one of the world's most disease-resistant
A closeup look at Burke, the latest pinto bean from ARS and university plant
scientists. It resists a host of harmful fungi and viruses that can otherwise
cheat growers of a bountiful harvest.
Plant exploration by its very nature has
always been an international activity. But now, worldwide political
developments are complicating free and open access to genetic resources.
USDA plant explorers have always obtained
permission from a host country for collecting. Today, it is not uncommon for
permission to be refused. Some germplasm donor countries feel that they have
not received a fair share of the benefits derived from the plant resources
originating in their countries.
To help change this perception and to keep
the pathways of germplasm exchange open, ARS has expanded collaborative
activities associated with plant exploration, explains ARS botanist Karen A.
Williams. She coordinates the ARS plant exploration program.
For example, Williams recently negotiated
terms with Paraguayan officials for a joint exploration trip looking for wild
relatives and traditional varieties of peppers, a popular U.S. crop that is
under-represented in ARS germplasm collections. During the exploration,
Paraguayan scientists got hands-on experience in germplasm collection.
Because Paraguay currently lacks modern
facilities to maintain the collected germplasm, ARS will provide long-term
storage on Paraguay's behalf. Whenever requested, samples of the germplasm will
be sent back, ensuring that unique germplasm will remain available to
Paraguayans--no matter what habitat or agricultural changes take place
In addition, ARS is helping train a
Paraguayan scientist in germplasm utilization. And to conserve wild peppers and
other crop relatives in their natural habitats, a study of the distribution of
these plants is being conducted using information from previous germplasm and
botanical samples. Working with Paraguayan institutions, ARS scientists will
provide recommendations for creation of protected areas for these
"Both the United States and Paraguay
are benefiting from collaboration on the pepper exploration and associated
activities," Williams says. Germplasm collected on USDA-supported
explorations is deposited into the National Plant Germplasm System, where it is
freely available to breeders and other researchers. Agriculture around the
world, including in the United States, has benefited enormously from the
extensive amount of germplasm that has been made available since the beginning
of the USDA program in 1898, Williams says.
Thanks to fruit-breeding research, we're able to enjoy more productive,
healthy, and flavorful new varieties of apples every year.
The formal USDA collection program began
with a single Congressional appropriation of $20,000 in 1898 and the hiring of
David Fairchild as chief, a position he held until 1928.
What Fairchild's plant explorers brought
back during this period profoundly affected agriculture in the United
In addition to Carleton's Russian wheat,
avocados, navel oranges, and other tropical fruit varieties collected by Wilson
Popenoe in South and Central America created new U.S. industries. The rice
brought back by Seaton A. Knapp from Japan not only opened up rice-growing in
Louisiana and Texas, it turned the United States into an exporter of rice
instead of an importer. Fairchild himself brought back dates, pima cotton,
pistachios, gooseberries, olives, walnuts, and many other specialties.
And then there was Frank N. Meyer.
Considered the dean of USDA's agricultural explorers, from 1905 to 1918 he
introduced thousands of plants. Although he is not well known to the public
today, consumers benefit from the bounty he brought back every time they shop
Collecting mostly in Asia and Russia, Meyer
sent back new crops--from alfalfa sprouts to zoysia grass. Apples, barley,
chestnuts, bean sprouts, Chinese celery-cabbage, and the Meyer lemon, which is
an important source of frozen lemon juice and is grown commercially in Texas,
South Africa, and New Zealand--these just scratch the surface of what Meyer
collected. He also brought back landscape plants and ornamentals: Bradford
pears, dwarf lilacs, Amur cherry, gingko trees, and a rose that provided the
rootstock on which millions of roses still bloom in the United States each
Most widely used of all the
drought-resistant trees that Meyer collected were Siberian and Chinese elms.
When the drought of the 1930s began to turn the prairie states into the Dust
Bowl, Meyer's elms formed a large part of the 17,000 miles of shelterbelts that
were created to reduce wind erosion. These tree-lined windbreaks planted
between 1935 and 1942 helped conserve millions of tons of soil.
One of Meyer's most significant
contributions was soybeans. Before he went to China in 1905, only eight
varieties of soybeans were grown in the United States, and these were for
animal forage. Between 1905 and 1908, Meyer added 42 new soybeans, which have
parented thousands of varieties over the years.
Among the soybeans that he collected was the
one that gave rise to soybean oil production, an industry worth billions of
One contribution of his did not quite take:
Meyer was ahead of his time in the early 1900s, when he advocated that the
United States should pick up on an Asian soybean industry and begin producing a
food called tofu.
It is hard to track the impact of what Meyer
and other USDA explorers brought back, because it can be decades before
selections from a collected plant can be further developed into a new variety.
For example, the zoysia grass that Meyer collected in the early years of the
century did not evolve into a commercial variety until 1951.
Fairchild established the plant inventory
system that remains in operation today. Each accession that enters the
germplasm system, whether it is collected by a plant explorer or the result of
a breeding program, is given a plant introduction number.
The first, PI 1, was a cabbage accession
from Moscow, Russia. Collected in 1898, it was said to mature a little earlier
than the Jersey Wakefield but to form heads too small for market.
Recently, PI 600,000 was awarded to a
pollinator sunflower with shorter-than-normal height. It promotes high yield in
hybrids and was developed in an ARS breeding program.
New accessions today receive PI numbers only
after an evaluation is done to determine that a plant represents new germplasm
for the collections. Germplasm is often sent to one of four Regional Plant
Introduction Stations managed by ARS at state agricultural experiment stations
(SAES) at Ames, Iowa; Geneva, New York; Griffin, Georgia; and Pullman,
Washington. These sites were originally chosen to represent the main
agricultural environments in the United States.
The plant introduction station system
created in 1948 by USDA and the SAES to maintain the collections of different
crops is celebrating its 50th anniversary this year.
ARS also set aside some locations for
specialized germplasm collections and in the 1980s, again with the SAES,
established repositories for clonally propagated fruit and nut crops.
All of these sites concentrate today on
maintaining, characterizing, and distributing the active collections for
"Because the collections have gotten so
large and resources are always limited, we focus on a core collection--about 10
percent of the main collection--that reflects the basic genetic diversity of a
crop that a researcher would need to screen to find a source for a particular
trait," explains Philip L. Forsline, who is curator of the ARS apple
collection at Geneva. It keeps cool-season grapes, Brassica (broccoli,
cauliflower, mustard, turnip), tomatoes, and some minor crops, as well as the
apples in which Forsline specializes.
"In the apple collection alone, we have
more than 2,000 named varieties. However, most of them, whether they are French
cider apples or domestic varieties from North America, New Zealand, or South
Africa, come from a very narrow genetic base," Forsline says. "That
is why we have made four trips since 1989 to collect wild varieties in
Kazakhstan, the center of origin for apples."
Whether breeders are trying to create a new
flavor or respond to an outbreak of apple scab, they turn to the collection at
Geneva as the definitive reservoir of apple genes.
On the other hand, long-term storage of the
entire germplasm collection is the job of ARS' National Seed Storage Laboratory
(NSSL) in Fort Collins, Colorado.
"We provide the backup to the active
collections," says Steve A. Eberhart, who heads the lab. "We are sort
of the Fort Knox for plants."
If a tornado, fire, or other disaster ever
hit one of the plant introduction stations or other ARS germplasm banks, NSSL
could replace lost varieties, Eberhart explains.
As one of the most advanced plant and seed
storage facilities in the world, NSSL has been asked by some countries and
international agricultural research centers to keep samples of their valuable
collections. For example, the International Rice Research Institute in the
Philippines has asked NSSL to keep a secure backup of its rice germplasm
because of concern that a typhoon could destroy parts of the collection. So
far, IRRI has not had losses from a natural disaster, but NSSL was able to
replace a few varieties that had been lost in the normal course of
"The seeds we keep secure here,"
says Eberhart, "are truly the world's treasure."--By J. Kim Kaplan,
Agricultural Research Service Information Staff.
"Conserving the World's
Plants" was published in the
September 1998 issue of Agricultural Research magazine.
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