Group Title: Agricultural research (Washington, D.C.)
Title: Agricultural research
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Title: Agricultural research
Uniform Title: Agricultural research (Washington, D.C.)
Physical Description: v. : ill. ; 25-28 cm.
Language: English
Creator: United States -- Science and Education Administration
United States -- Agricultural Research Administration
United States -- Agricultural Research Service
Publisher: Science and Education Administration, U.S. Dept. of Agriculture :
Science and Education Administration, U.S. Dept. of Agriculture :
Supt. of Docs., U.S. G.P.O., distributor
Place of Publication: Washington D.C
Publication Date: September 1998
Frequency: monthly[1989-]
bimonthly[ former jan./feb.-may/june 1953]
monthly[ former july 1953-198]
Subject: Agriculture -- Periodicals   ( lcsh )
Agriculture -- Research -- Periodicals   ( lcsh )
Agriculture -- Periodicals -- United States   ( lcsh )
Agriculture -- Research -- Periodicals -- United States   ( lcsh )
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Statement of Responsibility: U.S. Department of Agriculture.
Dates or Sequential Designation: Began with vol. 1, no. 1 (Jan. 1953).
Issuing Body: Vols. for Jan./Feb.-Nov. 1953 issued by: Agricultural Research Administration; Dec. 1953-<Sept. 1976> by: Agricultural Research Service; <June 1979>-June 1981 by: the Science and Education Administration; July 1981- by: the Agricultural Research Service.
General Note: Description based on: Vol. 27, no. 7 (Jan. 1979).
General Note: Latest issue consulted: Vol. 46, no. 8 (Aug. 1998).
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Bibliographic ID: UF00074949
Volume ID: VID00020
Source Institution: University of Florida
Holding Location: University of Florida
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Resource Identifier: ltuf - ABP6986
oclc - 01478561
alephbibnum - 000271150
lccn - agr53000137
issn - 0002-161X

Full Text

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Celebrating a
Century of Plant
1998 marks the 100th anniversary
of the U.S. Department of Agricul-
ture's plant introduction program, one
of the oldest continuing activities in
This year also marks the 50th anni-
versary of the four Regional Plant
Introduction Stations and the Inter-
Regional Potato Introduction Station
that were initiated by USDA collabor-
atively with state agricultural experi-
ment stations and are now managed
by and jointly funded with USDA's
Agricultural Research Service. This
year is also the 50th anniversary of
the National Small Grains Collection
and the 40th anniversary of the
National Seed Storage Laboratory.
These are all important compo-
nents of the National Plant Germ-
plasm System (NPGS) that maintains
and distributes plant germplasm ac-
quired from sources all over the
Plant germplasm contains all the
genetic information for a plant's
hereditary makeup. Scientists in the
United States and around the world
use plants and seeds of the nearly
10,000 species maintained in the
system to develop new and improved
varieties that underpin national and
global food security.
The United States, like most other
countries, depends on plants that orig-
inated elsewhere in the world for
most of its food supply. So scientists
everywhere need access to the global
gene pool.
The NPGS exists to preserve germ-
plasm of plants that might otherwise
be lost or unavailable to these scien-
tists. The more than 20 NPGS sites
maintain about 450,000 accessions,
each collected at a particular time and
place. These include seeds and other

parts of modern and old varieties,
wild and weedy relatives of crop
plants, and genetic stocks. Genetic
stocks are those with induced and
natural mutations, cytological
(cellular) stocks of genetic oddities,
and variations on normal chromo-
somes, marker genes, and pest-
resistant stocks.
Over the century since USDA
Secretary James Wilson created the
Section of Seed and Plant Intro-
duction, the history of this endeavor
has evolved, yet the mission has
remained the same: coordinate acqui-
sitions and preserve, characterize,
evaluate, and distribute germplasm.
Today, ARS' Beltsville (Mary-
land) Agricultural Research Center's
National Germplasm Resources Lab-
oratory facilitates plant explorations
supported by the NPGS. The Belts-
ville lab also assists curators at the
germplasm maintenance sites and
other scientists with the exchange of
germplasm with foreign countries.
Last year, the NPGS distributed more
than 108,000 samples of germplasm
to over 100 countries.
USDA has always considered ge-
netic resources to be the common
heritage of mankind. The department
maintains a policy of unrestricted and
free exchange of NPGS germplasm to
both domestic and foreign users.
Congress reaffirmed this policy in
1990 to show the U.S. commitment to
germplasm conservation and sharing.
Exploring for and collecting germ-
plasm has always involved interna-
tional cooperation. Foreign collecting
trips are planned and arranged as sci-
entific collaborations between the
United States and host countries. Col-
lected germplasm and herbarium
specimens are shared between partici-
pating countries.
In 1991, ARS created guidelines
for ethical conduct during plant ex-
ploration trips. The guidelines help
protect the natural environment and

ensure that the United States and co-
operating countries derive maximum
benefit from collecting trips.
In recent years, some countries
have voiced opposition to an open and
free exchange of germplasm as a glo-
bal policy because they feel that the
benefits derived from the use of germ-
plasm have not been shared equitably.
At the 1992 United Nations Earth
Summit in Rio de Janeiro, Brazil, the
Convention on Biological Diversity
was signed by more than 150 coun-
tries. This landmark pact, which
became effective in December 1993,
established that countries have the
right to regulate access to their plant
genetic resources and that the sharing
of germplasm is to be on mutually
agreed terms.
The issues of access to germplasm
and benefit sharing from germplasm
exchanges continue to be the subject
of a long-term negotiation of the In-
ternational Undertaking on Plant Ge-
netic Resources that is under the aus-
pices of the United Nations' Food and
Agriculture Organization (FAO)
Commission on Genetic Resources for
Food and Agriculture.
The United States hopes that the
FAO negotiations will lead to a satis-
factory compromise on very complex
issues. All countries agree that the
current global system can be im-
proved so that all countries can better
conserve, use, and benefit from these
valuable genetic resources.
Plant exchange will continue to be
vital to U.S. agriculture and the na-
tional economy. Also, as the global
population continues to grow, plants
maintained in the NPGS-freely ex-
changed among scientists around the
world-may make the difference be-
tween abundance and scarcity, surplus
or famine.

Allan K. Stoner
National Germplasm Resources
Laboratory, Beltsville, Maryland

Agricultural Research/September 1998

September 1998
Vol. 46, No. 9
ISSN 0002-161X

Agricultural Research is published monthly by
the Agricultural Research Service, U.S. Depart-
ment of Agriculture (USDA). The Secretary of
Agriculture has determined that this periodical is
necessary in the transaction of public business
required by law.
Dan Glickman, Secretary
U.S. Department of Agriculture
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Floyd P. Horn, Administrator
Agricultural Research Service
Sandy Miller Hays, Director
Information Staff
Editor: Lloyd McLaughlin (301) 504-1651
Assoc. Editor: Linda McElreath (301) 504-1658
Art Director: William Johnson (301) 504-1659
Acting Photo Ed.: Anita Daniels (301) 504-1609
Staff Photographer: Scott Bauer (301) 504-1607
Information in this magazine is public property
and may be reprinted without permission. Non-
copyrighted photos are available to mass media in
color transparencies. Order by photo number and
date of magazine issue.
Agricultural Research magazine articles and
photographs are posted on the World Wide Web
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Subscription requests should be placed with New
Orders, Superintendent of Documents, P.O. Box
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Complimentary I-year subscriptions are available
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and the news media. Send requests or comments
to: Editor, Agricultural Research, 5601 Sunny-
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This magazine may report research involving pes-
ticides. It does not contain recommendations for
their use, nor does it imply that uses discussed
herein have been registered. All uses of pesticides
must be registered by appropriate state and/or
federal agencies before they can be recommended.
Reference to any commercial product or service
is made with the understanding that no discrimi-
nation is intended and no endorsement by USDA
is implied.
The U.S. Department of Agriculture prohibits
di criminatii.o'i ;n all its programs and activities
on ihe bj~ i >'t race, color, national origin,
gender, religion, age, disability, political beliefs,
sexual orientation, and marital or family status.
(Not all prohibited bases apply to all programs.)
Persons with disabilities who require alternative
means for communication of program informa-
tion (Braille, large print, audiotape, etc.) should
contact USDA's TARGET Center at (202) 720-
2600 (voice and TDD).
To file a complaint of discrimination, write:
USDA, Director, Office ol (Ci il Rights, Room
326-W, Whitten Bldg., 14th & Independence
Avenue, SW, Washington, DC 20250-9410, or
call (202) 720-5964 (TDD). USDA is an equal
opportunity provider and employer.

Agricultural Research/September 1998

Agricultural Research

Conserving the World's Plants 4

Unique Peanuts Bring Nations Together 1

Saving Seeds for the Long Term 12

Not All Table Spreads "Butter Up" Blood Cholesterol

Cranberry-Pollinating Bee Wears a Mustache 1 6

Diagnostic Test for Cattle Tuberculosis 17

DHA Lowers Blood Triglycerides in Diet Study 18

EGPIC: An Automated Insect Census-Taker 20

New Test To Identify Screwworm Larvae 22

Cytokine Protein Helps Cows Fight Mastitis 22

Science Update 23

Cover: 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. Photo by
Scott Bauer. (K8191-21)

We have moved!

Our new mailing address is:
Agricultural Research Magazine
5601 Sunnyside Ave.
Beltsville, MD 20705-5130

Our new phone numbers are:
Editor: Lloyd McLaughlin (301) 504-1651
Associate Editor: Linda McElreath (301) 504-1658
Art Director: William Johnson (301) 504-1659
Acting Photo Editor: Anita Daniels (301) 504-1609
Staff Photographer: Scott Bauer (301) 504-1607

Correction: The August 1998 Forum referred to an "artificial diet that mimics the
potato beetle eggs that are the favored snack of Edovum wasps and their offspring."
The research on this diet is being done in Beltsville, Maryland.



the World's Plants

"The greatest service which can be rendered any
country is to add a useful plant to its culture."
-Thomas Jefferson, 1790

I n 1898, experts were predicting
food shortages and famine because
increasing population would over-
take our ability to grow sufficient
wheat by 1931. They may have been
right-except 1898 was also the year
U.S. Department of Agriculture spe-
cial 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 States.
Five years after the introduction
of wheat from Russia, wheat produc-
tion in the United States exploded
from 60,000 to 20 million bushels a
year. Not only did the drought toler-
ance 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 forgot-
ten how poor our bread was at the
time of Carleton's trip to Russia. In
truth, we were eating an almost taste-
less product, ignorant of the fact that
most of Europe had a better flavored
bread with far higher nutritive qual-
ities than ours."
One hundred years later, USDA
plant exploring and collecting, now
under the direction of the Agricul-
tural Research Service's National
Germplasm Resources Laboratory, is
still a critical ingredient in maintain-
ing and expanding agriculture's
ability to feed an ever-growing

So Many Plants, So Many Reasons
Plant exploring and collecting are
essential for agriculture because
crops must be continually enhanced
to overcome diseases and pests, ex-
pand drought and temperature toler-
ance, 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 im-
proved varieties.
"No one country or even one con-
tinent has all of the genetic resources
necessary to sustain crops at the lev-
el that is needed today," says Allan
K. Stoner, leader of the ARS germ-
plasm laboratory. "Conditions and
needs continue to change, and col-

SCOTT BAUER (K8187-12)

'* p

so ,
19 s?

** 1




Samples of seeds maintained at ARS'
National Seed Storage Laboratory in Fort
Collins, Colorado.

lecting genetic diversity is how you
have the resources to deal with
This is true for most countries, be-
cause so much now being grown
anywhere either arrived there with
immigrants who brought along their
traditional crops or was introduced to
that country by plant explorers. Most
of the United States' major crops-
fruits, vegetables, grains-originally
evolved in Asia, Europe, or South
Only 1 of the top 20 major world
crops originated in North America:
the sunflower, which now ranks
among the top 4 oilseed crops world-
wide. Of course, there are many
plants indigenous to North Ameri-
ca-including crops like strawber-
ries, blueberries, cranberries, forage
grasses, pecans, grapes, and tepary
beans-that are collected by both
U.S. and foreign plant explorers.
Interestingly, it was Russian re-
searchers 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 di-
versity, 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 cen-
turies may not be as highly produc-
tive as current varieties, but they can
have genetic traits that are exactly

Agricultural Research/September 1998

Agricultural Research/September 1998 5

Exploration in the 1990s
-- Plantcollecting has changed in many ways since USDA plant explorer
Frank N. Meyer walked a thousand miles from a railhead in China, collecting
samples:of any plant that looked interesting. He is shown here on February 26.
1908, returning "tired, but satisfied," from a successful expedition in the high
mountains of Shansi province in northern China.
Today, trips are elaborately planned to concentrate on filling specific gaps in
the plant collections of individual crops.
And the most modern technology now plays as big a role as the sturdy mules
of USDA's earliest plant explorers. For example, global positioning satellites
help pinpoint sites where new germplasm may be available for collection. And
explorers take along laptop computers to record their data.

what we need to overcome a pest or
disease problem," he says.
The wheat that USDA plant explor-
er Jack R. Harlan and his Turkish col-
league 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 sus-
ceptible 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 Introduction 178383.
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
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 re-
turned to Fakiyan Semdinli to collect
more of PI 178383 and other possibly
disease-resistant wheat.
In talking with the region's farm-
ers, Sperling discovered that they had
migrated to the area only in their
grandfathers' time. They had come

ARS botanist
Karen Williams
(center) and
Pedro Juan
Cavallero (left),
who is with the
Institute, and
Fatima Mereles,
with the National
University of
Asunci6n, search
for wild pepper

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 dis-
eases or the arrival of new insect pests
illustrates another critical reason for
having a standing germplasm collec-
tion that reflects a crop's range of
genetic diversity.
"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 un-
usually 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 repre-

Agricultural Research/September 1998

sent the diversity of a crop and its rel-
atives and preserve it until that day in
the future when a plant turns out to be
the single most important source of
some critical trait."
Another reason for plant collect-
ing-one that has become increasing-
ly urgent in recent years-is the need
to preserve germplasm endangered by
habitat destruction or the loss of tradi-
tional crop varieties.
ARS plant 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 cot-
ton 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 Agricultur-
al Experiment Station in Texas," says
But when he went to the Acala
Valley in 1984 to re-collect the origi-
nal germplasm, he couldn't find any
cotton at all.
"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 com-
mercial 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
Growers decided to eradicate what
was perceived as the source of the in-
festation-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 pre-
served 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.

Agricultural Research/September 1998

For example, Percival is concerned
about an interesting race of cotton
relatives-one with twice the custom-
ary 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 develop-
ing, building new hotels," says Per-
cival. "Who knows if these plants
will survive or disappear? Yet they
could well be the source of resistance
to insects."

An International Affair
Plant exploration by its very nature
has always been an international ac-
tivity. 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 re-
fused. Some germplasm donor coun-
tries feel that they have not received a
fair share of the benefits derived from
the plant resources originating in their


ARS botanist Karen
Williams and Pedro
Juan Cavallero
record data on a wild
pepper found near a
Toba tribal settlement
in Paraguay.

Until collected during a USDA-supported
plant expedition in Paraguay, this wild
pepper species, Capsicum schottianum, was
unrepresented in germplasm collections.
Both the flowering stage shown at top and
the fruiting stage were photographed by
Karen Williams.

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 co-
ordinates the ARS plant exploration
For example, Williams recently
negotiated terms with Paraguayan of-
ficials for a joint exploration trip
looking for wild relatives and tradi-
tional 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 germ-
plasm collection.
Because Paraguay currently lacks
modern facilities to maintain the
collected germplasm, ARS will pro-
vide 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 there.
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 plants.
"Both the United States and Para-
guay are benefiting from collabora-
tion on the pepper exploration and as-
sociated 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. Agri-
culture around the world, including in
the United States, has benefited enor-
mously from the extensive amount of
germplasm that has been made avail-
able since the beginning of the USDA
program in 1898, Williams says.

In the Beginning
The formal USDA collection pro-
gram began with a single Congres-
sional appropriation of $20,000 in
1898 and the hiring of David Fair-
child as chief, a position he held until
What Fairchild's plant explorers
brought back during this period pro-

At the Plant Genetic Resources
Conservation Unit in Geneva, New York,
horticulturist Philip Forsline examines
hybrid grapes developed in a USDA
breeding program.

foundly affected agriculture in the
United States.
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. in-
dustries. 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. Mey-
er. 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 bene-
fit from the bounty he brought back
every time they shop for groceries.
Collecting mostly in Asia and Rus-
sia, 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 impor-
tant 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 year.
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 re-
duce 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 va-
rieties over the years.
Among the soybeans that he col-
lected was the one that gave rise to
soybean oil production, an industry
worth billions of dollars today.
One contribution of his did not
quite take: Meyer was ahead of his
time in the early 1900s, when he ad-
vocated that the United States should
pick up on an Asian soybean industry
and begin producing a food called
It is hard to track the impact of
what Meyer and other USDA explor-
ers brought back, because it can be

Agricultural Research/September 1998

decades before selections from a col-
lected 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
Fairchild established the plant in-
ventory system that remains in opera-
tion today. Each accession that enters
the germplasm system, whether it is
collected by a plant explorer or the re-
sult of a breeding program, is given a
plant introduction number.
The first, PI 1, was a cabbage
accession from Moscow, Russia. Col-
lected in 1898, it was said to mature a
little earlier than the Jersey Wakefield
but to form heads too small for
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.

Plant Introduction Stations
New accessions today receive PI
numbers only after an evaluation is
done to determine that a plant repre-
sents new germplasm for the collec-
tions. Germplasm is often sent to one
of four Regional Plant Introduction
Stations managed by ARS at state ag-
ricultural experiment stations (SAES)
at Ames, Iowa; Geneva, New York;
Griffin, Georgia; and Pullman, Wash-
ington. These sites were originally
chosen to represent the main agricul-
tural environments in the United
The plant introduction station sys-
tem 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

Agricultural Research/September 1998

Apples in the ARS germplasm collection at
Geneva, New York, vary widely in size,
shape, and color.

clonally propagated fruit and nut
All of these sites concentrate today
on maintaining, characterizing, and
distributing the active collections for
particular crops.
"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, mus-
tard, 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 varie-
ties. However, most of them, whether
they are French cider apples or do-
mestic 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 cre-
ate a new flavor or respond to an out-
break 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 col-
lection is the job of ARS' National
Seed Storage Laboratory (NSSL) in
Fort Collins, Colorado.
"We provide the backup to the ac-
tive collections," says Steve A. Eber-
hart, 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 vari-
eties, 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 agricultur-
al research centers to keep samples of
their valuable collections. For exam-
ple, 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, ARS.
The scientists in this article can be
contacted through Kim Kaplan,
USDA-ARS Information Staff, 5601
Sunnyside Ave., Beltsville, MD 20705-
5130; phone 301-504-1637, fax 301-
504-1648, e-mail *

i- IT.1 W- I I IFIkK Q_'a- 1

Unique Peanuts Bring Nations Together

eanuts, native to South
America, are widely grown
on small farms in Ecuador,
which may have more varieties of
peanuts than any other country in the
The crop is planted in slash-and-
burn plots in the rainforests of the
Amazonian lowlands in the east and
in small fields on the sandy coastal
plains. Ecuadorian farmers also grow
peanuts on irrigated terraces along
river valleys in the dry southern
mountains. In the northern part of the
country, they grow them at high
To find and collect samples of this
peanut diversity, Agricultural Re-

Botanist David Williams, with the
International Plant Genetic Resources
Institute in Cali, Colombia, receives a
peanut landrace from a native farmer in
the Amazonian lowlands of Ecuador.


A peanut landrace of the variety aequatori-
ana, from Morona-Santiago Province.

search Service plant explorer Karen
A. Williams and colleagues from
Texas, Colombia, and Ecuador
traveled throughout the country in
1995 and 1996. Williams is a botanist
in the Plant Exchange Office of ARS'
National Germplasm Resources
Laboratory at Beltsville, Maryland.
Native varieties are commonly
known by scientists as landraces.
"Landraces," Williams says, "offer
rich sources of genes that breeders
can use to improve commercial
varieties. Resistance to pests, diseas-
es, and environmental stresses are
only a few of the useful traits that
may be found in these landraces.
"For centuries, the people of
Ecuador have selected peanuts that
grow best under their local conditions
and have particular characteristics
they prize. Different Ecuadorian
cultures have various uses for pea-
nuts and have selected seed for
specific traits, such as white peanuts
selected exclusively for use in
candy," says Williams.
In 1983, Donald Banks, an ARS
peanut breeder in Stillwater, Okla-
homa, collected peanut landraces in
three areas of Ecuador: Quito,
Guayaquil, and Loja. But large areas
remained unexplored, including the
Ecuadorian Amazon.
"This left major gaps in peanut
germplasm collections from Ecua-
dor," says Williams. "So in 1995 and
1996, we attempted to visit every
area of the country. The only place
we couldn't go was the far eastern
Amazonian lowlands, which are
accessible only by canoe."
Williams' mission was threefold:
fill gaps in the U.S. peanut collection,
re-establish a national peanut germ-
plasm collection in Ecuador, and
strengthen U.S.-Ecuadorian collabo-
ration in peanut and other genetic
Williams' 1995 trip included
botanist David E. Williams of the

International Plant Genetic Resourc-
es Institute (IPGRI) in Cali, Colom-
bia; and C6sar Tapia of the Ecuador-
ian Agricultural Research Center
(INIAP) near Quito. Williams made
the 1996 trip with Tapia and veteran
peanut explorer Charles E. Simpson
of Texas A&M University in
"In all, we collected more than
200 accessions of native peanut
landraces," Williams says. "The new
accessions include landraces of all
six botanical varieties of peanuts
(Arachis hypogaea): hirsuta, hy-
pogaea, fastigiata, peruviana,
aequatoriana, and vulgaris. This
shows the broad genetic diversity of
peanuts available in Equador. Some
of the landraces were previously
unknown to science."
Of the several aequatoriana
landraces they collected, only two
were previously known. "Ecuador is
the center of diversity for aequatori-
ana, which has large, rough-looking
pods containing three to five colorful
seeds," Williams says.
"Peanuts of the rare hirsuta
variety, named for their densely
hairy stems and leaves, were also
collected. The hairs may deter
insects from feeding and laying eggs.
The hirsuta peanut is believed to
tolerate cold and drought better than
other peanuts. In the northern
highlands near the Equator, we
found a hirsuta landrace at an
altitude of 8,790 feet-the highest
altitude of any peanut ever collect-
ed," says Williams.

A Two-Way Street
Ecuador gained from collabora-
tive activities that resulted from-
and reached beyond-the plant
"The political climate for germ-
plasm exploration has changed
dramatically in recent years,"
Williams says. "International agree-

Agricultural Research/September 1998

11-. .

ments have caused some countries to
place restrictions on distribution of
germplasm. To keep the doors of
exchange open, it is increasingly
important for the U.S. Department of
Agriculture to find new ways of
collaborating with countries that
provide germplasm."
After germplasm is collected,
plants must be multiplied and their
characteristics scientifically detailed,
or described, before they are distrib-
uted to plant breeders. Rather than
increase and characterize the Ecua-
dorian peanut collections in the
United States-the standard proce-
dure-this work was performed in
Ecuador by Ecuadorians under
contract with USDA.
The increased seeds were divided
between the United States and
Ecuadorian national plant collections.
ARS arranged for Charles Simpson
to travel to Ecuador to train the
Ecuadorians in methods for peanut
characterization, using the USDA
Peanut Descriptor List-a standard-
ized set of details about peanuts.
"In addition to gaining a fully
increased and characterized peanut
collection, the Ecuadorians now have
the technical knowledge to manage
it," says Williams.
"These joint efforts make sense to
both countries," she says. "Each
would have had to increase and
characterize the same accessions-a
duplication of effort-if this project
had not taken place. We accom-
plished the same goals at a much
lower cost to both countries. And we
initiated interactions between Ecua-
dorian and U.S. peanut scientists."
Another feature of this collabora-
tion was making use of the ARS
peanut collection to restore the
Ecuadorians' set of germplasm
collected in 1983 by ARS' Donald
Banks. That material had been lost in
Ecuador because of inadequate
storage conditions.

Agricultural Research/September 1998

A farmer (left) and Cesar Tapia, who is with the Ecuadorian Agricultural Research Center,
examine a rare peanut grown in the highlands of Imbabura Province, Ecuador.

"Ecuador now has a new, state-of-
the-art national genebank where this
repatriated germplasm can be safely
stored," Williams says.
Other activities resulting from the
peanut explorations will benefit
Ecuador and other countries. An
example is a new Geographic Infor-
mation System (GIS) for Ecuadorian
peanut germplasm that will correlate
locations of Ecuador's peanut land-
races with environmental, socio-
economic, and cultural variables.
"The GIS will help zero in on
peanut diversity in Ecuador and other
countries and will thus aid in planning
future peanut explorations," says
Williams. It will also help match
environmental requirements of
landraces with other locations for
possible new introductions. USDA,
IPGRI, and the International Center
for Tropical Agriculture are collabo-
rating to develop the GIS.
In addition, the landraces are being
cataloged. The work is being done by
a world authority on their taxonomy,
Antonio Krapovickas, at the North-
eastern Botanical Institute in Corri-
entes, Argentina, in collaboration
with ARS. The catalog will build on
previous unpublished descriptions of
Ecuadorian landraces and include
taxonomic keys, descriptions, illustra-
tions, and distribution maps.

"When completed, this catalog will
substantially increase the usefulness
of the collections and," Williams
says, "be a helpful tool for monitor-
ing these resources on the farms
where they are being grown.
"We won't know how many land-
races of each variety, such as A. ae-
quatoriana, or how many total land-
races we collected until Krapovickas'
study is finished," she says.
"The projects stemming from the
peanut explorations in Ecuador show
the mutual benefits that result from
international collaboration in plant
genetic resources," says ARS horti-
culturist Allan K. Stoner. He heads
the National Germplasm Resources
Laboratory, which coordinates USDA
plant exploration trips worldwide.
"Projects like this," says Stoner,
"help keep avenues of access open
and ensure the continuation of
ongoing international efforts to
conserve, study, and use genetic
resources for the benefit of all."-By
Hank Becker, ARS.
Karen A. Williams is in the USDA-
ARS Plant Exchange Office, National
Germplasm Resources Laboratory,
10300 Baltimore Ave., Beltsville,
MD, 20705-2350; phone (301) 504-
5421, fax (301) 504-6305, e-mail *

Saving Seeds for the Long Term

Electron microscopy produced this freeze-
fracture replica of a portion of a cryo-
preserved cell taken from the growing
region of an embryo of tea, Camellia
sinensis. Optimizing water content and
super-rapid cooling allow aqueous glasses
to form in seed cells. This preservation
technique doesn't appear to cause
damaging ice crystals to form. Magnified
about 15,000x.

Using a differential scanning calorimeter,
plant physiologist Christina Walters can
detect phase-state changes of water and
lipids in seeds. First she cools thin slices of
seed tissues sealed in tiny aluminum pans
(held in tweezers) to -170C. The relation-
ship she finds between a seed's water con-
tent, temperature at which its heat capacity
changes, and size of the change give clues
about the nature of glasses that form.

W ill seeds in storage today
sprout and grow when
they're needed-years,
even centuries, from now?
To find out, Agricultural Research
Service plant physiologist Christina
T. Walters is investigating little-
known glass compounds in super-
chilled seeds.
That's right, glass. It holds a key
to keeping the seeds viable.
"All seeds contain glasses that are
composed of water and other cellular
constituents," says Walters. "These
aqueous glasses have properties
similar to the silica glass in win-
dows-except that they form at
temperatures hundreds of degrees
lower. Our data suggest that they
consist of a highly complex intercel-
lular substance-perhaps a carbohy-
drate or protein mixture."
For 11 years, Walters has been
researching optimum conditions for
storing seeds at ARS' National Seed
Storage Laboratory (NSSL) in Fort
Collins, Colorado.
Some 300,000 germplasm acces-
sions representing about 8,000
species are stored at the facility. It is
the largest gene bank in the world
and is part of the ARS-maintained
National Plant Germplasm System
(NPGS) that collects plants from all
over the world. Curators and other
scientists preserve, evaluate, and
catalog the vast collections and
distribute germplasm to breeders who
use it to develop new varieties.
If scientists could accurately
predict seed viability, the continual
monitoring of stored seeds would be
unnecessary. "This monitoring for
viability is the most labor-intensive
part of seed storage in gene banks,"
says ARS plant physiologist Eric E.
Roos, who heads the Plant Germ-
plasm Preservation Research Unit at
Fort Collins.

"Seeds stored at optimum condi-
tions can last for hundreds, maybe
thousands, of years, obviating the
need to continually regrow sam-
ples-the most expensive part of
germplasm preservation," he adds.
It's critical to determine how to
keep stored germplasm alive and
capable of germinating and produc-
ing fruiting parts for many years. But
"when stored seeds deteriorate, they
lose vigor," says Walters. "They
become more sensitive to stresses
upon germination. Eventually, they
lose their ability to grow."

Aging-It's Inevitable
Whether stored in soil banks,
warehouses, or liquid nitrogen, all
seeds eventually succumb to aging.
"Seed aging," says Walters, "has
enormous implications for the seed
industry. It defines the changes in
quality that occur from the time the
seed is harvested until its germinated
plant emerges from the soil."
The rate at which a seed ages is
determined by its initial quality, its
moisture content, and its storage
"We have known for many years
that manipulating these factors
influences seed longevity," says
Walters. "But their precise interac-
tion is poorly understood, so we are
unable to predict longevity for a
particular seed lot."
A major goal is to identify seeds
that are "good keepers" or to spot
"bad keepers" before they begin to
deteriorate and to develop predictive
tools for the rate of deterioration.
Walters found that two big influ-
ences on deterioration are the nature
of water binding within seeds and the
effect of the bound water on seed
cells. Investigating further, she
applied thermodynamics and con-
cepts from materials and food

Agricultural Research/September 1998

Glass in seeds holds secrets for predicting the best way to store them.

sciences to predict optimal moisture
content for storing any seed at any
That's where seed glasses come in.
"The glassy concept explains the role
of water in food deterioration," says
Walters. She uses this same concept
to describe how seeds' intercellular
tissue responds to changing water
contents and temperature.

Seeking the Ideal
Scientists at the lab are using
Walters' approach to predict opti-
mum conditions for seed storage.
"Preconditioning seeds by holding
them at 5oC and 25 percent relative
humidity for a few weeks achieves
optimal water content for long-term
storage at -18oC," she says.
To measure changes in glass in a
seed cell, Walters uses a differential
scanning calorimeter. "This equip-
ment measures the energy required
for a phase transition, such as when
ice melts and changes from a solid to
a liquid," she says.
Walters scanned at least 30
different seed species at temperatures
from -1800C to over 1000C to see
what types of phase changes occur in
seed cells when seeds contain differ-
ent amounts of water.
"Glasses control the aging rates in
seeds by controlling the rate of
chemical reactions," she says.
"Glasses make seed cells very
viscous, so molecules move slowly.
And glasses have small pores,
preventing some molecules from
moving at all. The slower the molec-
ular motion, the slower the chemical
reactions and the aging rate."
Dense, viscous glasses make seed
last longer. But "if the glasses in seed
are fluid, the seed will age faster,"
she adds.
Walters has studied glasses in
dried and frozen beans, peas, soy-

beans, corn, sunflowers, peanuts,
lettuce, wild rice, coffee, tea, papay-
as, macadamia nuts, and yew seeds.
She has even studied glasses in
pollen from cattails and corn.
"Glasses in seeds that have been
dried too much become porous," she
says. "But glasses in seeds that are
insufficiently dried are too fluid.
Neither will store well or long."
Each plant species has a different
optimal moisture content for storage.
"That value changes with tempera-
ture," she says. "It can take more
than a decade to directly measure it at
storage temperatures used in germ-
plasm banks-that is, at 5C, -18C,
or -196oC. We can't do this for each
of the 8,000 NPGS species."
Still, Walters' findings have
provided reliable clues as to optimal
combinations of water content and
temperature. She also investigates
how chemical constituents in the seed
affect the glasses. Some seeds form
stable glasses-dense, with low
porosity. "This contributes to differ-
ent aging rates, even if the seed is
stored at the optimal water content,"
she says.
Walters does not yet know what
chemicals are most important for
stable glass formation. But she knows
they are produced in bean seeds
during the final days of maturation.
Walters plans to learn more about
how the glasses form and how they
control molecular motion. "The
knowledge will enable us to accurate-
ly predict the rate of deterioration for
a specific seed lot before deteriora-
tion begins," she says.
According to Roos, "This informa-
tion is vital to germplasm banks, such
as the NSSL, in planning germination
test schedules and choosing which
seed lots are in need of closer moni-
toring and/or regeneration."
He adds, "Cost savings achieved
when we reduce monitoring and

regeneration of good seed lots allow
resources to be applied to preserva-
tion of other types of seed or to
clonal germplasm."-By Hank
Becker, ARS.
Christina T. Walters and Eric E.
Roos are at the USDA-ARS National
Seed Storage Laboratory, 1111 S.
Mason St., Fort Collins, CO 80521-
4500; phone (970) 495-3202, fax
(970) 221-1427, e-mail +

Plant physiologist Christina Walters is
lowering a container of seeds into a vat of
liquid nitrogen that will cryopreserve them.
These vats can hold 5,000 containers of up
to 2,000 seeds each. The longevity of seeds
stored in this fashion is projected to be
thousands of years, but scientists periodi-
cally remove samples to assess their viabil-
ity and vigor.

Agricultural Research/September 1998

Not All Table Spreads "ButterUp"

Blood Cholesterol

T he 46 volunteers in a study
at the Beltsville (Maryland)
Human Nutrition Research
Center could tell the difference
between butter and those other
But they couldn't distinguish
between the margarines with and
without trans fats. Only the dietitians
who prepared the meals knew for
sure. Researchers and volunteers
were kept in the dark during the 15-
week study, to ensure objectivity.
On weekdays, the volunteers ate
breakfast and dinner in the Beltsville
center dining rooms and carried
lunch to their jobs. Weekend meals
were carried home in a cooler for
later warming. Volunteer Sandra
Laase says, "You had to eat every-
thing they gave you-and you
couldn't eat anything extra."
According to Vickie Lopez, a
veteran of several studies at the
Beltsville center, "The study got hard
when there were holiday luncheons.
We had to carry our brown bags with
our prepared lunch and eat that." But
the researchers agreed to let the
volunteers eat their own dinner on
Thanksgiving and Christmas, as long
as they used the butter or margarine
provided and recorded what they ate.
The question asked by researchers
Joseph T. Judd, David J. Baer, and
Beverly A. Clevidence was: "Do dif-
ferences in blood lipids show up with
minor changes in fatty acid profiles
among the three spreads?" says study
leader Judd. "Butter is the standard.
Americans desire hardened fats in
their spreads and baked goods."
They also want fats that reduce
risk of cardiovascular disease. So the
food industry partially hydrogenates
vegetable oils for consumer accep-
tance. And that process produces
trans fatty acids, or trans fats.
Scientists have been concerned
about their health effects for nearly
as long as oils have been hydrogen-

ated. Until 1990, the evidence leaned
toward no adverse effects.
Then a Dutch study showed that
high intakes of trans fats did indeed
raise cholesterol, says Judd-espe-
cially the artery-damaging LDL
cholesterol. Four years later, Judd,
Baer, Clevidence, and colleagues
reported similar effects on blood
lipids when volunteers in an earlier
study at the Beltsville center con-


Physiologist David Baer sorts vials of
plasma and serum stored at -80OC that will
be used for lipid analyses.

sumed as little as one-third the trans
fats fed in the Dutch study.
It's possible to harden products
such as table spreads without hydro-
genation, says Judd. The margarines
in this study were specially made by
Lipton in Baltimore, Maryland.
Their composition is compared in
the chart on page 15.

Trans-Free Fats Look Best
The 23 men and 23 women volun-
teers consumed each spread for 5
weeks as part of a typical U.S. diet.
That is to say, 35 percent of total cal-
ories were fat, 15 percent were pro-
tein, and 50 percent carbohydrates.

Most Americans don't eat as much
butter or margarine as fed in this
study, says Baer, noting that the
spreads accounted for 8 percent of
total calories. That's about 2 to 3
tablespoons each day. "We wanted to
be able to see small changes in blood
lipids," he says.
Analysis of the volunteers' blood
samples showed a stairstep effect
from the three spreads:
Butter evoked the highest LDL
and total cholesterol levels.
After eating the trans-fat marga-
rine for 5 weeks, the volunteers' total
cholesterol was 3.5 percent lower
than with butter, and their LDL was
down 5.4 percent.
Five weeks of consuming the
non-trans-fat margarine hardened
with the innocuous stearic acid
produced the lowest levels. Com-
pared to butter, total cholesterol was
down 4.7 percent and LDL was 6.7
percent lower.
"There's only one conclusion that
can be reached," says Judd. "You
limit trans fats in the diet where you
can. But don't get overly concerned
to the point where you substitute
saturated fats for trans fats. Saturated
fats average about 12 percent of the
total calories in the diet and are a
major dietary factor in cardiovascular
disease risk.
"If it's tub margarine, which
softens at room temperature, and the
primary fat on the label is liquid
vegetable oil, it's okay," says Judd,
"even if it contains some trans fats.
"Even better," he notes, "may be
some of the economical trans-free
margarines that are coming on the
market." More of these will follow as
consumers demand alternatives.
Chemically speaking, trans fatty
acids are monounsaturated fatty acids
like oleic acid-the principal fatty
acid in olive and canola oils. Health-
wise, they are not equal. The body
perceives trans fats more like the

Agricultural Research/September 1998

cholesterol-raising saturated fats.
Vegetable oils high in oleic acid, on
the other hand, tend to reduce blood
cholesterol when they replace
saturated fats.
Baer says that on average, 2 to 3
percent of total calories in the
American diet comes from trans
fats. And only about 10 percent of
that intake is contributed by the
naturally occurring trans fats in red
meat, milk, and other dairy prod-
ucts. The rest comes mostly from
partially hydrogenated oils in
margarines, in shortening used in
baked goods such as cookies,
pastries, and icings, and in restau-
rant fried foods.
Noting that she normally eats
junk food, Lopez says, "I've always
felt healthier when I've done a study
because I eat better."
Laase concurs. "I was probably
the healthiest when I was on the
controlled diet," she says. "And we
took no vitamins. It's probably the
only time I ate breakfast." Laase
says she enjoyed the study, noting
that the discipline got difficult only
toward the end.

One Fatty Acid at a Time
With the table spread study under
their belts, Judd, Baer, and col-
leagues wanted to tease apart the
effects of individual fatty acids that
raise, lower, or have no effect on
blood lipids. As each table spread
was changed, several fatty acids
changed in the diets, explained
Baer. The follow-up study varied
levels of one fatty acid or mixture of
them at a time.
Over the course of 7 months, the
researchers tested five diets differ-
ing in fatty acids and one with extra
carbohydrates. Two fatty acids-
oleic and stearic-and extra carbo-
hydrates served as controls. The
other three fatty acids tested were
trans fats, trans fats plus stearic

Agricultural Research/September 1998


In studies to determine the effects on cholesterol of eating different table spreads, food
service workers Sarah Mayock (left) and Diana Shegogue prepare meals for controlled diets
while chemist Joseph Judd looks on.

acid, and a combination of three
cholesterol-raising saturated fats.
When results are finalized, they will
help clarify the evidence needed for
expert panels to reach consensus on
the remaining dietary fat questions.
To make informed choices, "the
public needs clear health messages
from organizations like the Ameri-
can Heart Association, National In-
stitutes of Health, and the U.S. De-
partment of Agriculture," says
Judd.-By Judy McBride, ARS.

Joseph T. Judd and David J. Baer
are at the USDA-ARS Diet and
Human Performance Laboratory,
Beltsville Human Nutrition Research
Center, Bldg. 308, 10300 Baltimore
Ave., Beltsville, MD 20705-2350; fax
(301) 504- 9098;
[Judd] phone (301) 504-9014, e-mail
[Baer] phone (301) 504-8719, e-mail *

Cornpvui-5&on ol Spreads Studied

Typical Margarine

Fats (%)

Non-Trans Margarine 0

Fats (%)



SSource: Joseph T. Judd, Agricultural Research Service
", ". -. -, ... :. ,_; ; 'ss. ;" *, ,, , , ; :,_ . ". ,, '. 1 5

Fats (%)


Acid (%)



Pollinating Bee

Wears a


E very child knows bees live in
hives, make honey, pollinate
flowers, and deliver a sting if
provoked. But if pollinating cranber-
ries is the goal, there may be another,
better-suited bee.
Consider Anthophora abrupta, or
the mustached mud bee, so called
because the males use a pheromone-
soaked mustache to woo females in
the spring.
"Solitary bees are valued only for
their skill as pollinators," says
Agricultural Research Service
entomologist Suzanne W.T. Batra,
who is at the ARS Bee Research
Laboratory in Beltsville, Maryland.
"They do make honey from nectar,
but they make only a little. And they
mix it with pollen and their own body
secretions to make beebread for their
Mustached mud bees are truly as
American as the cranberries they may
someday be used to pollinate. These
native bees live in dry clay walls and
cliffs, not in hives. The adults fly
during early summer; the rest of the
year, they live inside nests. They
look like small, fast-flying bumble
Unlike honey bees, whose repro-
duction is a privilege for the queen,
every solitary bee female has a
chance at motherhood and the work
of gathering food. They are called

mud bees because females build
chimneys of mud at the nest entranc-
es. Mud bees are not as likely to
sting as honey and bumble bees.
Harold E. Bechmann, who is with
the University of Delaware, was
helped by Batra with testing these
bees as pollinators for cranberry
bogs. He explains why they're more
gentle than honey bees.
"Mustached mud bees don't have
the large investment of calories,
pollen, and wax that honey bees put

into a hive," Bechmann says. "A hive
is a honey bee's life."
Obviously, these bees were
interesting to scientists, but would
they be pollinating pros for cranber-
ries? Wet, cold cranberry bogs do not
seem like fun places for any bee, but
mustached mud bees are active in
June during cranberry bloom. The
trick would be building up a large
enough population and getting the
bees to stay-in spite of the cold,
dampness, and wind.

Together, Batra and Bechmann
gathered bees for the experiment.
Some came from Bechmann's
collection, which he found in an old
stone farmhouse near Elkton, Mary-
land, that was built in 1735-when
clay was used as mortar for homes.
Batra gave him more bees that she
found nesting in an old adobe chicken
coop near Baltimore.
"These bees are such homebod-
ies," says Bechmann. "It's hard to get
them to move to new manmade adobe
abodes. The way they see it, what
was good for the last generation of
bees is still good enough for them."
Batra gave Bechmann insights on
making the bees more comfortable in
their new homes. Wood posts sup-
porting blocks of dry clay nests seem
to work.
The first year met with little
success, the second year went better,
and each year the bees seem more
adept at life in the bog.
"The land's flat, there're no trees,
and the wind blows like mad," says
Bechmann. "But I've checked
mustached bees we've released in the
bogs and, sure enough, the females
had gathered cranberry pollen on
their legs."
Future yield data will show how
effective these bees are as pollinators,
Batra says. "Cost and ease of man-
agement will also be important
factors."-By Jill Lee, ARS.
Suzanne W. T. Batra is at the
USDA-ARS Bee Research Laborato-
ry, Bldg. 476, BARC-East, 10300
Baltimore Ave., Beltsville, MD
20705-2350; phone (301) 504-8384,
fax (301) 504-8736. +

Agricultural Research/September 1998

Diagnostic Test for Cattle Tuberculosis

new test that detects cattle
tuberculosis bacteria
within 3 days is a major
improvement over current methods
that can take up to 3 months.
Mycobacterium bovis-the culprit
in cattle tuberculosis-is similar to
two other bacteria, M. avium and M.
paratuberculosis. The inability to
distinguish among the three has been
a problem in eliminating the disease.
The new test, developed by ARS
veterinarian Janice M. Miller at the
National Animal Disease Center
(NADC) in Ames, Iowa, allows
researchers to quickly tell
which organism has infected an BRUC
animal. Miller developed the
test at the request of USDA's
Animal and Plant Health
Inspection Service (APHIS).
That agency needed the test to
aid in joint efforts with state
animal inspection agencies and
U.S. livestock producers to
eradicate cattle TB.
The test uses polymerase
chain reaction (PCR), a tech-
nique that makes many copies
of certain genetic material
found only in M. bovis. Making
so many copies of the targeted
DNA allows easy identification
of M. bovis, which couldn't be
seen before PCR amplification.
Extensive tests in other labora-
tories have proven that this
piece of DNA isn't present in
M. avium or M. paratuberculo-
sis. Researchers recently
developed new tests using the
same technology to identify
both of these organisms.
Miller and others at NADC
and at APHIS' National

Speedier diagnosis
will allow officials to
take immediate action
to identify the most
common sources of
cattle tuberculosis.

Using the new test for cattle tuberculosis, biological
technician Dennis Orcutt loads an agar gel with PCR-
amplified tissue material from the thermal cycler
(foreground). He will know within 3 days if the culture
contains Mycobacterium bovis bacteria.

Agricultural Research/September 1998

Veterinary Services Laboratory in
Ames validated the PCR test by
examining 99 known cases of TB in
cattle and elk. In 93 percent of the
cases, they could make an accurate
diagnosis within 2 to 3 days after
receiving the tissue samples.
The speedier diagnosis will allow
APHIS officials to take immediate
action to identify the most common
sources of cattle tuberculosis: import-
ed Mexican steers, the captive elk and
deer population, and large dairy herds
with low levels of infection.
TB spreads when coughing releas-
es the bacteria into the air.
Although human tuberculosis
p in the United States is usually
S caused by a different bacteri-
um-M. tuberculosis-the M.
bovis organism can cause TB
in humans, and M. tuberculosis
can cause TB in livestock and
other animals.
Humans don't get TB from
eating meat or drinking milk
from infected animals because
Pasteurization and appropriate
cooking temperatures kill the
disease organism. When milk
pasteurization standards were
developed in the 1920s, M.
bovis and M. tuberculosis were
considered the most resistant
pathogens then known.-By
Linda McGraw, ARS.
Janice M. Miller is in the
USDA-ARS Respiratory and
Neurologic Diseases Research
Unit, National Animal Disease
Center, P.O. Box 70, Ames, IA
50010; phone (515) 239-8349,
fax 239-8458, e-mail *

DHA Lowers Blood Triglycerides

in Diet Study

H igh blood levels of fats
known as triglycerides
may increase risk of heart
disease. So may an unhealthy ratio of
the good HDL cholesterol to the bad
LDL cholesterol. Coronary heart
disease that can result from these or
other factors kills more Americans
than any other disease.
Scientists with the Western
Human Nutrition Research Center
have seen triglyceride levels go down
in volunteers who ate meals supple-
mented with a moderately high level
of DHA, a polyunsaturated fatty acid.
DHA is short for docosahexaenoic
(DOE-coe-suh-hex-uh-noy-ick) acid.
The center, part of USDA's Agricul-
tural Research Service, is in San
Francisco, California.
Volunteers on a DHA-enriched
regimen also showed an increase in
HDL cholesterol, the kind known to
protect against heart disease.

What's more, DHA may do this
without unwanted side effects such as
prolonged bleeding time or slower-
than-normal blood clotting. These
negative effects have been found in
some studies of another polyunsatu-
rated fat known as EPA, or eicosa-
pentaenoic (EE-coe-suh-pent-uh-noy-
ick) acid. EPA and DHA belong to
the family of omega-3 fatty acids.
"From results with our small group
of 10 volunteers," says ARS research
chemist Gary J. Nelson, "it appears
dietary DHA may be beneficial in
altering an individual's risk of
cardiovascular disease. But longer
studies are needed before we can be
The study was designed to help
separate the effects of DHA and
"In fish oils, in particular," says
Nelson, "these two polyunsaturated
fats have been of intense interest in

Chemists Darshan Kelley (left) and Gary Nelson analyze data from the longest
yet reported with in-residence volunteers.

nutrition research since the 1970s.
That's when studies suggested that
the cardiovascular health of Green-
land Eskimos might result in part
from the predominance of oil-rich
fish in their diets. Purported benefits
include lowering the total amount of
triglycerides in the blood.
"Fish and fish oils contain both
DHA and EPA," Nelson says. "Of
the two, EPA is predominant in fish
that live in cold oceans. The presence
of both EPA and DHA makes it
difficult to determine which of the
two is the major contributor to the
health benefits claimed for fish or
fish oil."
To help differentiate the effects of
DHA and EPA, Nelson and col-
leagues used a natural oil extracted
from golden algae that contains 40
percent DHA-but no EPA. This
substance, according to Nelson, "has
only recently become available as a
source of purified DHA."
For the experiment, Nelson
collaborated with chemists Darshan
S. Kelley, Perla C. Schmidt, and
Giovanni L. Bartolini, of the nutrition
center, and David J. Kyle, vice
president of Martek Corp. The
Columbia, Maryland, company
manufactures the DHA-rich oil used
in the study.
Ten volunteers-healthy, non-
smoking males aged 20 to 39-lived
at the research center for the 4-
month-study-the longest DHA ex-
periment reported with in-residence
volunteers. For the first 30 days, the
volunteers ate a baseline diet that
provided less than 50 milligrams a
day of DHA.
For the remaining 90 days, 6
grams-about a teaspoon-of the
DHA-rich oil was mixed with salad
dressings or with bean, guacamole, or
salsa dips served to six of the volun-
teers. That's about 100 times more
DHA per day than most Americans

Agricultural Research/September 1998

consume. The other volunteers got
safflower oil instead.
All meals for all volunteers were
very low in EPA. To ensure that all
the men received enough antioxi-
dants, they took a 100-milligram
vitamin E capsule every 5 days.
Meals featured familiar foods
prepared with precision by the
research center's dietary staff. One
day's menus included, for instance,
buttermilk pancakes, maple syrup,
and sliced bananas for breakfast;
canned peaches, sliced ham with jack
cheese, lettuce, and mayonnaise on
whole-wheat bread for lunch-with a
salad of sliced cucumbers and french
dressing on the side. A dinner of
canned pineapple, roast chicken with
teriyaki sauce, brown rice, and green
beans was followed by chocolate
cake as the evening snack.
Triglycerides in blood decreased
by about 26 percent in volunteers on

Chemist Perla Schmidt uses a rotary evap-
orator to remove solvent from lipids extrac-
ted from volunteers' blood samples. She is
putting dry ice in the top of the evaporator
to cool and condense the solvent for

Gas chromotography enables chemist Giovanni Bartolini to evaluate DHA samples
obtained from participants in the San Francisco test.

the DHA regimen. Their HDL
cholesterol-the good kind-rose an
average of 9 percent.
The DHA-supplemented group
also showed an increase of about 69
percent in apoprotein-E. This com-
pound carries cholesterol from
peripheral tissues back to the liver for
breakdown and excretion. Increased
apo-E, Nelson says, "has not been
reported in other DHA or EPA
studies with humans."
Nelson and co-workers looked at
several indicators of normal bleeding
and clotting. They found no signifi-
cant differences in these measures
before or after the high-DHA diet.
"That's unlike fish oils," says Nelson.
"They have been shown to increase
bleeding times. Fish oils have also
been shown to inhibit aggregation of
blood platelets needed to form clots."
DHA and EPA are essential to
good health. Our bodies need fats to
carry fat-soluble vitamins like A, D,
and K; to make steroid hormones; to
keep skin healthy; and to perform
other biochemical chores.
But health officials today generally
recommend that fats take up no more
than 30 percent of each day's total
calories. Saturated fats-ones like
butter and lard that stay solid at room
temperature-should make up no
more than 10 percent.-By Marcia
Wood, ARS.
Gary J. Nelson, Darshan S. Kelley,
and colleagues are at the USDA-ARS
Western Human Nutrition Research
Center, P.O. Box 29997, Presidio of
San Francisco, CA 94129;
[Nelson] phone (415) 556-0899,
fax (415) 556-0425, e-mail
gnelson @
[Kelley] phone (415) 556-4381,
fax (415) 556-1432, e-mail *

Agricultural Research/September 1998

EGICAn Autom ate

Inec aesu- ake

S tored grains, fruits, nuts,
vegetables, and other foods
are a smorgasbord for rice
weevils, sawtoothed grain beetles,
and other insects that feast on stored
products. Insect infestations cause
millions of dollars in annual stored
product losses and fumigation costs.
But the free lunch for these pests
may soon be over. Scientists at the
Center for Medical, Agricultural,
and Veterinary Entomology
(CMAVE) in Gainesville, Florida,
have developed a high-tech system
that exposes the gluttonous meal
The new pest detector, developed
by electrical engineer Dennis
Shuman, is called the Electronic
Grain Probe Insect Counter, or
"Low insect populations are
difficult to detect in small samples,
so a much greater proportion of the
grain needs to be sampled to accu-

rately estimate the size of an insect
population," he says.
A probe trap is a perforated tube
inserted into grain that insects crawl
into and then drop through into a
reservoir at the lower end. Presently,
probes are left in grain bins for
prolonged periods, until an inspector
manually removes and visually
inspects them-a time-consuming
and sometimes difficult procedure.
"These methods are expensive, so
they are not repeated often. This
allows infestations to grow from
undetectable to damaging levels in a
matter of weeks," says Shuman.
EGPIC is an enhancement of
current grain probe trap technology.
It uses an infrared beam sensor to
quickly, accurately, and economi-
cally record and time-stamp insects
as they drop through the probe.
Shuman says the probes can be lo-
cated throughout a grain bin or eleva-
tor. Their sensors can transmit insect

In their Gainesville laboratory, entomologist Nancy Epsky and electrical engineer Dennis
Shuman test EGPIC probes. Displayed on the computer screen are the total number of
insect counts, time elapsed since the last count, total time the probe was active, and status of
the probe.

counts back to a central computer via
SMARTS, a data transmission net-
work Shuman designed and patented
for large-scale monitoring.
While current methods give only a
snapshot of what's going on, EGPIC
provides a continuous moving picture
of what's happening inside a storage
bin-and an accurate picture, having
a 95 percent counting accuracy rate
in lab tests.

Best of All, It's Flexible
Shuman's version has an adaptable
design and can be customized,
depending on the type of stored
product and storage environment.
Environmental factors such as
temperature, humidity, noise and
vibration, dust, and chemical pesti-
cides won't throw off its results.
Current traps require routine
maintenance and have a finite life,
since they fill up with insects and
have to be emptied or removed. To
reduce this maintenance, Shuman is
working on a version that has a long,
open-ended tube below the sensor so
insects can be counted and released
lower in the bin-virtually eliminat-
ing the need for trap servicing.
Monitoring stored-product insects
is important mainly for two reasons:
Insect infestations can cause high
damage and losses if left unchecked,
and they require costly chemical
EGPIC allows companies to avoid
or reduce insecticides. "General
practice has been to make scheduled
pesticide treatments-independent of
knowing how big the problem is,"
says Shuman.
By accurately estimating the distri-
bution of an insect population, com-
panies may not have to treat the en-
tire bin. The new system allows them
to target treatments by knowing what
is going on at any given moment.

Agricultural Research/September 1998


- --I..

A live lesser mealworm adult drops through
a cutaway-but operational-EGPIC
probe. The insect snapped its own picture
in mid-fall when it intersected an infrared
beam, triggering an electronic flash.

This is a big advantage, consider-
ing the proposed worldwide ban on
methyl bromide, a widely used,
highly effective fumigant used for
stored product insect control. The
United States, in accordance with the
U.S. Environmental Protection
Agency's Clean Air Act, plans a
phaseout of methyl bromide by the
year 2001.
Currently, there is no single re-
placement for it. Companies will ulti-
mately have to use a combination of
treatments, which could increase the
cost of fumigating. Pinpointing infes-
tations and knowing their severity
will allow companies to better plan
their fumigation strategies.
More EGPIC benefits:
It requires minimal maintenance
at sensing sites to permit monitoring
at hard-to-reach locations.
It's capable of sensing all
different stored product insect pest
species at low densities.
It's compatible with other grain
management systems.
It can be used without extensive

Agricultural Research/September 1998

Shuman says EGPIC is ready for
Eight copies of the prototype
EGPIC system are being evaluated in
lab and field tests with different
products, climates, and locations.
"We want to see if different
conditions affect the system and, if
necessary, adapt the system to meet
those conditions," says Shuman.
"Research with this new tool may
also reveal new approaches to moni-
toring pest population dynamics."
Entomologists Nancy D. Epsky
and Richard T. Arbogast are each
testing one of the copies. "The
biggest problem with traps is relating
trap catch to the population density,"
says Epsky, who works at CMAVE.
Epsky is evaluating the system's
performance for detecting a broad
range of insects. "I'm going to look at
insect density and species and how
they will affect the system. We're
trying to take all possible situations
and determine if they have an impact
on count accuracy," she says.
For instance, Epsky thinks insect
behavior may affect the trap count.
She says certain insects are more
"grabby" and thus more likely to fall
down in pairs and to be counted as
one insect.
Also, insect shape and size play a
role and affect the size of a sensor's
output signal. "By analyzing this
information and compiling guide-
lines, the EGPIC system can be
configured to discriminate between
different insect species based on their
size," Epsky says. "We're hoping to
fine-tune the system, so we can more
precisely determine what species is
infesting the grain."
Trap catch is also related to
temperature and other characteristics
of the insect's environment, such as
grain moisture content and the
amount of open space between grain
kernels, says Arbogast, who is also
based at CMAVE.

"These relationships must be
defined, to maximize the value of
EGPIC for monitoring insect infesta-
tions in actual storage situations," he
says. Recognizing this, Shuman has
incorporated automated temperature
and humidity monitoring into the
overall system design.
Among other sites testing the pro-
totypes are ARS labs in Manhattan,
Kansas, and Fresno, California, along
with researchers at Oklahoma State
University in Stillwater and at Mon-
tana State University in Bozeman.
A modified version of EGPIC
called BICAP (Beneficial Insect
Counting and Packaging Device,
patented) uses an EGPIC sensor head
and cups on a computer-controlled
turntable to count and package mass-
reared beneficial insects more effi-
ciently than by hand. Walt Disney
World's EPCOT Center at Orlando,
Florida, has been using the system to
count and package Opius dissitus, a
parasitic wasp reared in their laborato-
ry as a biological control for leafminer
pests in gardens throughout Disney
"EGPIC is one step towards high-
tech monitoring. Our focus continues
to be on innovative sensing methods
for detecting insect infestations in and
around stored products," says
Shuman.-By Tara Weaver, ARS.
Dennis Shuman, Nancy D. Epsky,
and Richard T. Arbogast are with the
USDA-ARS Center for Medical,
Agricultural, and Veterinary Entomol-
ogy, 1700 SW 23rd Dr., Gainesville,
FL 32604; fax (352) 374-5781,
[Shuman] phone (352) 374-5737,
dshuman @ gainesville. usda. ufl. edu
[Epsky] phone (352) 374-5761, e-
mail nepsky @ gainesville. usda. ufl. edu
[Arbogast] phone (352) 374-5719,
tarbogast@ gainesville. usda. *

New Test To Identify Screwworm

The same technology that brought pregnancy test kits
home is now being used to help identify larvae of the
screwworm, Cochliomyia hominivorax, in the field. The
test can differentiate them from those of a related screw-
worm, C. macellaria, which is not harmful to cattle.
A new test developed by ARS scientists at the Midwest
Livestock Insects Research Laboratory in Lincoln, Nebras-
ka, makes quick work of a complex identification process
to distinguish screwworm larvae from close relatives in the
fly family.
The test is expected to be used at airport terminals and
other ports of entry to identify suspicious insects found on
dogs, horses, and other animals which can carry screw-
worm larvae. Currently, specimens must be viewed in a lab
under microscopes by trained entomologists.
Called an ELISA, for enzyme-linked immunosorbant
assay, the test will make it easier for scientists and agricul-
tural officials in developing countries to identify and track
screwworm infestations and accidental re-introductions
and to positively identify laboratory populations quickly
and easily.
Little or no training is required to use the kit. Just crush
a suspect larva in a small container and add a few drops of
the kit's enzyme. If the sample turns a distinctive blue
color, the larva was a screwworm.
"This test is important because the screwworm larva
and its close relatives can be easily confused in the prima-
ry larval stages," says ARS entomologist Steve R. Skoda.
"This test allows anyone to make a positive identification
so steps can be taken to prevent an accidental infestation."
Before its eradication in the 1970s, screwworm was one
of the most serious insect pests of the domestic livestock
industry. It devastated livestock populations across the
southern United States and in Mexico, costing cattle
producers hundreds of millions of dollars each year.
The adult female lays her eggs in living tissue, and the
larvae hatch and feed on the wound, creating an opportu-
nity for bacterial infections. Other females lay more eggs
in the infected wounds and continue the cycle. Many
screwworm-infested animals die.
The screwworm has been eradicated from the United
States, Mexico, and part of Central America to Nicaragua.
It still persists in Costa Rica and Panama.-By Dawn
Lyons-Johnson, ARS.
Steve R. Skoda is at the USDA-ARS Midwest Livestock
Insects Research Laboratory, University of Nebraska, 305
Plant Industry, P.O. Box 830938, Lincoln, NE 68583-
0938; phone (402) 437-5267, fax (402) 437-5260, e-mail *

Cytokine Protein Helps Cows
Fight Mastitis

Mastitis, an infection of the mammary gland, affects
more than half of all U.S. dairy cows and costs the dairy
industry more than $180 per cow annually.
Marcus E. Kehrli, Jr., an ARS veterinary medical
officer at the National Animal Disease Center at Ames,
Iowa, has discovered that giving cows a natural compound
helps them ward off mastitis. The cows already make this
protein-cytokine G-CSF-in skin and other body cells. It
stimulates bone marrow to produce white blood cells that
help the immune system fight infections.
In recent studies, Kehrli injected cows with the com-
pound daily from days 3 through 7 after calving. On the
6th day, the cows were challenged with a bacterium, and
their response was monitored for several more days.
The good news is that one-half of the cows receiving
G-CSF did not become infected when challenged with the
bacteria. The other half of the G-CSF-injected cows had
shorter and less severe infections than cows in the control
group. All of the control group cows became infected and
developed mastitis.
"Besides protecting a good number of cows, we were
able to reduce the severity of infections by using this
compound," Kehrli says. Cows receiving G-CSF had good
appetites and gave more milk than those not receiving it.
The benefit of using G-CSF as a preventative: less use of
antibiotics in cows to treat mastitis.
Over the past decade, Kehrli and A.E. Freeman, an
Iowa State University (ISU) professor of animal science,
have been developing a way to identify the genetic source
of resistance to mastitis. So far, they have identified a few
cows that are naturally more resistant to mastitis
The ARS and ISU researchers are currently collaborat-
ing with 21st Century Genetics-CRI, a bull stud company
in Shawano, Wisconsin. As a result of this collaboration,
producers may someday be able to purchase cows that
have been bred for mastitis resistance.-By Linda Cooke
McGraw, ARS.
Marcus E. Kehrli, Jr., is in the USDA-ARS Metabolic
Diseases and Immunology Research Unit, National
Animal Disease Center, P.O. Box 70, Ames, IA 50010;
phone (515) 239-8462, fax (515) 239-8458, e-mail *

Agricultural Research/September 1998

Lighting Up Food's Fat Content
Shining invisible light on a beef
patty could lead to a safer, cheaper,
faster, more environmentally friendly
method for figuring out how much
saturated fat is in the burger. The
Food and Drug Administration
regulates chemical methods of fat
analysis used in the food industry to
control quality and obtain fat values
for food labels. Agricultural Research
Service scientists are testing a
nonchemical alternative called NIR,
or near-infrared reflectance spectros-
copy. Near-infrared light is just
outside the visible part of the light
spectrum. Chemical methods can
pose disposal problems and can take
2 days to yield results; NIR takes less
than 2 minutes and uses no ether or
other hazardous chemicals. A com-
puter measures how much of saturat-
ed fat's near-infrared light signature
is absorbed by a food sample, com-
pared to samples with known fat
content. To improve the technology,
ARS has entered into a cooperative
research and development agreement
with Foss North America of Eden
Prairie, Minnesota. Foss supplies
automated rapid-analysis tools for the
food and agriculture industries. ARS
and Foss plan to develop similar
techniques for chicken, sausage, and
pork. William R. Windham, USDA-
ARS Quality Assurance Research
Unit, Athens, Georgia; phone (706)
546-3513, e-mail


Bioimpedance To Estimate
Expectant Moms' Water-Weight
A technique for measuring water-
weight gain during pregnancy could
increase the odds that an expectant
mother will deliver a healthy, normal-
weight infant. Several factors in-
crease the risk of low-birth-weight
infants-less than 5-1/2 pounds. They
include inadequate diet, overly
vigorous exercise, diuretics, and drug
abuse. Such infants have an even
greater risk than preemies of health
complications. Physicians have long
known that moderate water accumu-
lation during pregnancy strongly
indicates proper fetal growth. An
ARS-led investigation (reported in
Agricultural Research, September
1994) was likely the first to show that
bioimpedance spectroscopy may offer
a safe, accurate, inexpensive way for
physicians to detect subnormal gains
soon enough to help patients take
corrective action. Scientists with
ARS, University of California at
Berkeley, and Xitron Technologies,
Inc., San Diego, California, conduct-
ed the study. They tested bioimped-
ance spectroscopy with 10 women
before and during pregnancy and
after delivery. In the technique, which
takes less than 2 minutes, a harmless
current is passed between electrodes
on the mother's hand and foot. A
computer processes the information
and prints an estimate of water load,
or "total body water." Measurements
from the scientists' test correlated
significantly with the babies' birth
weights. With further study, bio-
impedance may augment ultrasound
monitoring. Marta D. Van Loan,
USDA-ARS Western Human Nutrition
Research Center, San Francisco,
California, phone (415) 556-5729, e-
mail mvanloan @

Pine Mulch Goes Technicolor
Pine straw mulch-in blue, red,
brown, gold, black, and green-could
also put more green in farmers'
wallets. ARS scientists developed
these designer mulches, which are
being marketed to gardeners, home-
owners, and landscapers. Like other
mulches, colored pine straw con-
serves soil moisture, moderates soil
temperature, and helps stifle weeds.
Recent studies show the colored
mulch doesn't change soil pH. But
the environmentally safe dyes greatly
slow down the straw's decomposi-
tion, compared to uncolored pine
straw or conventional wood chips.
Colored mulches could generate 30
to 50 percent more profit-$400 to
$800 more per acre-for farmers
who usually grow pines for pulp and
timber. Farmers can harvest pine
straw when trees reach 8 years old.
But harvesting every year may tax
the tree's own growth and its envi-
ronment. Scientists advise harvesting
only from trees with needles over 6
inches, for ease in baling. The best
species are longleaf pine-with its
foot-long needles-along with
loblolly pine and slash pine. Catalino
A. Blanche, USDA-ARS Dale
Bumpers Small Farms Research
Center, Booneville, Arkansas, phone
(501) 675-3834, e-mail

Pine needle mulch.

Agricultural Research/September 1998

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