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 1997
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: VID00010
Source Institution: University of Florida
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issn - 0002-161X

Full Text


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J /



Many Rewards
From International
Agricultural researchers in the
United States today are repeating
Christopher Columbus' explorations,
in reverse. Scientists with the Agri-
cultural Research Service are travel-
ing from the New World to the Old in
search of solutions to key agricultural
problems: how to combat a devastat-
ing crop pest, boost plants' resistance
to a particular disease, or increase
plants' tolerance to adverse settings.
That's because so many of the
crops we now consider "as American
as apple pie" are actually borrowed
from other lands-soybeans from
China, wheat from the Mediterranean
and southwest Asia, rice from Asia.
In fact, there's been a steady
stream of new crops to this country,
carried by the unceasing human river
that started with a handful of English
settlers at Jamestown, Virginia, in
1607. And just as many of our crops
hailed originally from other shores,
so did many of our crop pests. For
example, Hessian flies that supposed-
ly came to this country with merce-
nary troops fighting in the American
Revolution ultimately waged war on
the U.S. wheat crop. Descendants of
boll weevils that migrated northward
from Central America in the 1890s
today cost the U.S. cotton industry
$300 million annually.
This agency-and American
agriculture-have already benefited
in many ways from international
cooperation, with the promise of
many more rewards to come. A few
0 ARS scientists at Baton Rouge,
Louisiana, are collaborating with
Russian scientists on studies of bees
from Russia's Primorsky region that
appear more resistant than U.S. bees
to the devastating varroa mite. Within

U.S. honey bee colonies, this mite
has taken a drastic toll since it arrived
from Mexico in the mid-1980s.
American beekeepers must typi-
cally treat their colonies twice to
fight back the mites, whereas Russian
beekeepers treat only once annually
and find far fewer varroa mites in
their colonies. If the Russian bees
have some extraordinary built-in
resistance to the mites, they might
eventually be made available to U.S.
beekeepers for breeding or cross-
breeding, as a natural alternative to
current chemical treatments of
fluvalinate to combat the mites.
An ARS researcher teamed with
scientists in Brazil, Poland, and
Mexico to find a gene in rye that
could help wheat, a major food
staple, grow on millions of acres
worldwide that are now inhospitable
to the crop. The gene enables wheat
to resist toxins in aluminum often
found in acid soils-the type of soil
that covers 5 billion acres in this
country and overseas. If wheat can be
adapted to tolerate aluminum-heavy
soils, the vital result could be signifi-
cantly more food for a mushrooming
world population.
ARS and French scientists have
collaborated on development of
reliable technology to transfer new
genes into insects. Agricultural
benefits could include reducing the
need for chemical insecticides by
increasing effectiveness of beneficial
insects that attack weed and insect
pests. But the possible benefits reach
far beyond the farm: Genes might be
transferred into mosquitoes, for
example, that would prevent them
from transmitting the parasite that
causes malaria, the killer of about 2.7
million people worldwide every year.
Collaboration between ARS
researchers and a professor of
biological sciences in Kazakhstan has
resulted in American explorations in
the mountains of Kazakhstan and

Kyrgyzstan to collect wild apple
germplasm that might harbor genes to
help U.S. apples naturally resist pests
and diseases. It's believed that the
domestic apple, Malus x domestic,
was born and evolved in Central
Asia's rugged mountain terrain. A
trip in 1993 resulted in gathering of
129 apple samples, called accessions,
including many in the wild species
Malus sieversii, a major genetic
contributor to the apples grown in the
United States. Some of the seedlings
grown from seeds gathered on the
1993 trip have shown natural resis-
tance to apple scab, a fungal disease
that's one of the most serious prob-
lems for apple growers.
International cooperation takes
many forms: swapped cotton germ-
plasm in Uzbekistan; a winter nursery
for cotton and kenaf at Tecoman in
Mexico for use by American federal,
private, and university plant breeders,
courtesy of a joint agreement be-
tween the Mexican government and
the United States' National Cotton
Council; field tests of hairy vetch as a
natural mulch for vegetable crops in
Poland; and, as you'll read in this
issue of Agricultural Research
magazine, collaborative efforts with
South Africa to develop new blooms
for the American floral industry-
and new markets for small South
African farmers.
By giving researchers the freedom
to go back to crops' historical roots to
find natural resistance to or natural
enemies of important crop pests, we
dramatically increase the odds that
the projected 9-billion world popula-
tion in the year 2046 will have
sufficient food, drinkable water, and
clean air. No matter which seat you
occupy at the world's table, that's a
worthwhile goal.

A. Rick Bennett
Actg. Assist. Admin., ARS Office of
International Research Programs

Agricultural Research/September 1997

September 1997
Vol. 45, No. 9
ISSN 0002-161X

Agricultural Research is published monthly by
the Agricultural Research Service, U.S.
Department of Agriculture, Washington, DC
The Secretary of Agriculture has determined
that this periodical is necessary in the transac-
tion of public business required by law.
Dan Glickman, Secretary
U.S. Department of Agriculture
I. Miley Gonzalez, Under Secretary
Research, Education, and Economics
Edward B. Knipling, Acting Administrator
Agricultural Research Service
Sandy Miller Hays, Acting Director
Information Staff
Editor: Lloyd McLaughlin (301) 344-2514
Assoc. Editor: Linda McElreath (301) 344-2536
Art Director: William Johnson (301) 344-2561
Acting Photo Editor: Scott Bauer (301) 344-2957
Assoc. Photo Ed.: Anita Daniels (301) 344-2956
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.
Subscription requests should be placed with
New Orders, Superintendent of Documents,
P.O. Box 371954, Pittsburgh, PA 15250-7954.
See back cover for order form.
Complimentary 1-year subscriptions are
available to public libraries, schools, employees
of the U.S. Department of Agriculture, and the
news media. Send requests or comments to:
Editor, Agricultural Research Magazine, Room
408, 6303 Ivy Lane, Greenbelt, MD 20770. E-
To visit Agricultural Research magazine on the
Internet, go to and select
News and Information.
This magazine may report research involving
pesticides. It does not contain recommendations
for their use, nor does it imply that uses dis-
cussed herein have been registered. All uses of
pesticides must be registered by appropriate
state and/or federal agencies before they can be
Reference to any commercial product or service
is made with the understanding that no discrimi-
nation is intended and no endorsement by the
U.S. Department of Agriculture is implied.
USDA prohibits discrimination in its programs
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religion, age, diabii3t), pohlical beliefs, and
marital or familial status i Not all prohibited
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(Braille, large print, audiotape, etc.) should
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nity employer.

Agricultural Research/September 1997

Agricultural Research

GEM Searches for Treasures in Exotic Maize 4

Soybean Cyst Nematodes, Look Out! 7

Floral Gems-New Blooms for America's Markets 8

Cooperation Delivers Livestock Embryos 14

Reviving Trap Cropping 1 6

Stopping Erosion With Gypsum and PAM 18

Polyacrylamide Keeps Soil in Its Place 21

Helping Cereals Resist Head Scab 22

Steadfast Trefoil's a Survivor 22

Science Update 23

Wild new blooms from
South Africa (page 8).

Seed companies live by their
reputation when selling
farmers disease-resistant and
high-yielding seed corn.
Now these firms are rely-
ing on ARS scientists to KEITH WELLER (K
help them in an all-out ef-
fort to breed their elite
lines using tropical or
other exotic corn.
The Germplasm En-
hancement for Maize, or --
GEM, project is a mas-
sive effort to develop
commercially attractive
hybrids containing germ-
plasm that is exotic-that
is, from outside the United
States. There are 19 com-
panies involved and 39 public re-
search facilities.
For half a century, scientists have
been trying to breed exotic/domestic
lines for companies to cross to
produce hybrids that farmers would
buy. The summer of 1996 marked the
first time public and private research-
ers cooperatively field-tested GEM
breeding materials with both exotic
and domestic germplasm. The tests
were at Raleigh, North Carolina, and
35 other U.S. locations.
"Latin American maize germplasm
has been extensively collected," says
Marty L. Carson, who is in the ARS
Plant Science Research Unit at
Raleigh. "But until now, most of the
exotic germplasm was being stored
like museum pieces and helping no
GEM is a followup to ARS'
multinational Latin American Maize
Project, or LAMP, that was financed
by Pioneer Hi-Bred International of
Des Moines, Iowa. LAMP evaluated
13,000 Latin American and U.S. corn
varieties for their breeding value and
narrowed the number of candidates
down to 260. The GEM program is
currently using the top 51 picks from
LAMP and 7 tropical hybrids donated

by DeKalb Genetics of DeKalb,
"Everyone wants their corn lines to
have a broader genetic base, but


developing these lines can take about
20 years-with no guarantee of
success. Private companies are
reluctant to allocate resources to such
a long-term effort," says Randall N.
Holley. He is a maize germplasm
enhancement specialist in Henderson,
Kentucky, working with Novartis
Seeds, the seed company created by
the merger of Ciba Seeds and
Northrup King. "This project
wouldn't be possible outside of a
public/private partnership."
Holley hopes private and public
financial support grows for this
program because as the domestic gene
pool for corn becomes more closely
related, less can be done to enhance
yields, and varieties become ever
more vulnerable to disease. GEM
received half a million in public funds
in 1996, and companies gave
$450,000 in in-kind contributions.

You've Got To Check 'em Out
Under GEM, seed companies cross
their top corn lines with promising
exotic sources and send the resulting
hybrids to public researchers like
Carson, who can test their yields and
disease resistance.

"We've been evaluating for
resistance to a host of disease patho-
gens, including fusarium ear rot, grey
leaf spot, southern leaf blight, and
Aspergillus flavus,"
says Carson. "We may
be throwing out a lot of
poor performers, but
we're also finding
germplasm with real
value for U.S. breeding
"There are 300 races
of corn in the world,
and the United States
uses one-Corn Belt
Dent," says Carson's
collaborator, Major
Goodman, who is a William Neal
Reynolds distinguished professor at
North Carolina State University. "It
seems somewhat silly to say that out
of all that genetic material we have
the best of everything."
Corn originated in what is now
Latin America. Since exotic varieties
thrive in that environment that lacks
killing frosts to give respite from
pests and fungi, they must have
evolved powerful resistance, says
Not that crossing exotic and do-
mestic lines is simple. Corn in Chia-
pas, Mexico, grows year round, rely-
ing on the sun for cues on when to
stop growing and reproduce. That
close to the equator, daylight doesn't
extend much beyond 12 hours. But
exposed to Iowa's 5-month growing
season with its 8:00 p.m. summer
sunsets, the Mexican corn may shoot
up to 20 feet and flower late in Sep-
tember-just in time for killing frosts.
Previous studies by the plant
science research group at NC State
found that only a small number of
genes control photosensitivity. This
opened the door to modifying the trait
by selective breeding.

Agricultural Research/September 1997

New, climate-adapted corn
germplasm will do more than
enhance corn yields and resistance to
disease. Providing a source of traits
such as improved protein, starch, and
oil composition and easier process-
ing characteristics is also an impor-
tant goal, says ARS geneticist Linda
M. Pollak of Ames, Iowa. She
coordinates the GEM program.
This year Pollak and ARS biolo-
gist Susan A. Duvick will work in
the field and lab with 6,000 breeding
lines derived from LAMP's and

DeKalb's materials. The lines were
developed for traits such as high
protein, high oil, or both; high starch;
and various fatty acid compositions.
The researchers analyze for fatty
acid content to catalog the potential
of GEM materials to change the
composition of oil in specialty corns.
A corn oil high in palmitic acid
would be in demand for margarine
production, requiring less chemical
processing. And cooking oil high in
oleic acid would be beneficial to
consumers' health, says Mack N.

Shen, an ARS food technologist
working with Pollak and staff of
Iowa State University's Center for
Crops Utilization Research.
Development of specialty corns is
an avenue for increasing the U.S.
share of the agricultural export
market and helping domestic users
avoid buying corn as a commodity of
somewhat variable quality.
A major quality trait improvement
on the grain industry's wish list is
kernels that are hard and less suscep-
tible to breakage. Pollak and her


North Carolina State University professor Major Goodman (left) examines the offspring of a cross between a tropical corn from Chiapas,
Mexico, and a private midwestern line. It shows little southern corn leaf blight, whereas B73, a domestic midwestern genetic stock being
checked by ARS plant pathologist Marty Carson, is extensively blighted.

Agricultural Research/September 1997

James Nyanapah, a North Carolina State University Ph.D. candidate in plant pathology,
prepares a culture of Exserohilum turcicum, the fungus that causes northern leaf blight.
He will use it to inoculate corn plants, to test their blight resistance.

"Linda Pollak's been analyzing these
exotics' oil and protein content. It
would be great to find a promising
candidate to cross with elite lines."
Raising oil from 4 percent to 6
percent would bring faster growth in
swine and poultry, Harper says.
That's why, he explains, feed
producers would like to see the
changes and why companies like
Holden's are trying to meet their
expectations.-By Jill Lee and Ben
Hardin, ARS.
To reach scientists mentioned in
this article, contact Jill Lee, USDA-
ARS Information Staff, Room 439,
6303 Ivy Lane, Greenbelt, MD
20770; phone (301) 344-2783, fax
(301) 344-2311, e-mail *


colleagues have found some exotic
flint corns with harder grains than
U.S. hybrids that can be crossed in
small amounts with Corn Belt
germplasm without reducing farm-
ers' yields.
On another encouraging note,
GEM scientists have found many
genes in exotic germplasm that cause
natural modifications of cornstarch.
These findings have bearings on
issues such as storability characteris-
tics and food product texture. Some
specialty starches could help certain
food products maintain a gel struc-
ture during freezing and thawing,
remain unaltered by heating, or resist
degradation when incorporated into
acidic foods such as tomato paste,
salad dressings, and lemon pudding.
Cornstarch research at Ames is
moving forward with a new rapid
viscoanalyzer that measures the ease
with which starch solutions flow.
Duvick, who is GEM's value-added
traits specialist, is investigating the

relationship of the viscosity of starch
to digestibility. Breeding corn for
improved digestibility, as well as
enhanced protein and oil composition,
would enable livestock to produce
more milk or meat with less feed.
Pollak says at least two high-
yielding lines with protein levels
above 16 percent and oil levels of
about 6 percent are being developed
from GEM breeding crosses. Corn
Belt hybrids typically have less than
10 percent protein and about 4 percent
oil. Increasing these nutrients in corn
fed to livestock could reduce the need
for more expensive soybean meal
used to balance rations.
"The livestock feed industry wants
corn with more oil. They also want
changes in starch and protein content
and quality," says corn breeder David
Harper, who is with Holden's Founda-
tion Seeds.
"Many exotics were used for
human consumption, so they might
enhance nutrient value," he says.

The greener leaf of the tropical corn line
on the left shows that it is more resistant
to corn leaf blight than the severely
damaged domestic leaf on the right.

Agricultural Research/September 1997

Soybean Cyst Nematodes, Look Out!

L ike a stealth army, soybean
cyst nematodes, Heterodera
glycines, can invade a
soybean field and cause plant damage
and yield loss without ever being
seen-until it's too late. This nema-
tode is the No. I disease pest of
soybeans, contributing to annual
losses estimated at 64 million bushels
The soybean cyst nematode feeds
on the roots of soybeans. It is named
for the egg-filled cyst that forms
from the body of the female and
overwinters in the soil. The eggs
hatch the following spring.
Soybean growers may lose 10 to
15 percent of their yield to this
pest-even before they see any
physical evidence of the nematode,
says Gregory R. Noel. He is an
Agricultural Research Service plant
pathologist in the Crop Protection
Research Unit at Urbana, Illinois.
"By the time a grower sees the
telltale yellow plant leaves, the nema-
tode has probably been present in the
soil for a decade or more," he says.
Now some relief is on the horizon.
Noel has been studying a bacterial
parasite that may expand growers'
defenses. Small-scale field trials
indicate Pasteuria can keep soybean
cyst nematode infestations below the
economic damage thresholds.
Pasteuria attacks the nematode
and uses it to complete its own life
cycle, killing the nematode in the
process and thus reducing damage to
the soybeans.
The bacterium is an obligate
parasite. This means it must have the
soybean cyst nematode to complete
its life cycle.
It reproduces by means of spores
called endospores that are released
into the soil. These attach to juvenile
nematodes moving through the soil in
search of a root to use to complete

their own life cycles. The spores then
germinate and infect the nematodes.
Noel reports the bacterium was an
effective control of soybean cyst nem-
atodes in his own experiment plots.
"Over an 8-year period, we saw a
decline in nematode populations in
plots in which we were attempting to
grow the nematodes for our experi-
ments," he says.
"My graduate assistant, N.
Atibalentja, has just completed a 3-
year study of the Pasteuria and
soybean cyst nematode populations.
We believe it may be a new species,
because it is morphologically distinct
from the only other Pasteuria found
on soybean cyst nematodes, which
was reported from Japan several
years ago.
Soybean growers have a limited
arsenal of defenses against the
nematode, Noel says.
"Several years of careful manage-
ment are required to reduce nematode
populations below damaging levels."
Farmers have had to rely on crop
rotation with nonhost crops-like
corn-and planting resistant soybean
varieties to deal with soybean cyst
"Resistance is most effective when
used with crop rotation to lower
nematode populations," says Noel.
"But even then, there are races of
soybean cyst nematode for which
there is no resistance. So the grower's
only option is to plant a nematode-
susceptible soybean and suffer yield
losses," he says.
The next steps in Noel's research
are to identify the species of Pasteur-
ia and to determine the effectiveness
of this bacterium as a biological
control agent for soybean cyst nema-
todes.-By Dawn Lyons-Johnson,
Gregory R. Noel is in the USDA-
ARS Crop Protection Research Unit,

N-325 Turner Hall, University of
Illinois, 1102 South Goodwin,
Urbana, IL 61801; phone (217) 244-
3254, fax (217) 244-4419, e-mail *

The bodies of female soybean cyst
nematodes feeding in plant roots form
bulbous, egg-filled nodules from which
young will hatch the following spring.

Agricultural Research/September 1997

he U.S. National
Arboretum in Washing-
ton, D.C., is a unique r
installation in the
Agricultural Research .
Service. Of around 100
ARS locations world-
wide, it is the only one
that serves as an educa-
tion center and national
garden, as well as a
federal research labora-
tory. This year, the U.S. Plant breed
National Arboretum, one plants to U.S
from right)
of the largest arboretums Commission
in the country and the
only federally funded
one, celebrates its 70th anniversary.
The anniversary celebration began
in March with the unveiling of
"Celebrating Science: 70 Years of
Discovery" by arboretum director
Thomas S. Elias. "This exhibit
highlights the many accomplishments
of the arboretum since it was estab-
lished," he says.

er Gail Littlejohn (right) explains the growth habit
. Department of Agriculture Secretary Dan Glickn
and members of the U.S.-Republic of South Africa I
's agriculture committee.

The celebration continues this fall
with special exhibits of fresh and
dried floral plants, highlighting
exotic and rare cut and potted plants
from South Africa. Sponsored jointly
by USDA's Agricultural Research
Service, the South African Embassy,

and the Agricultural
Research Council
(ARC) of South Africa,
the month-long autumn
exhibition will showcase
the great floral diversity
of South Africa and the
progress of mutually
beneficial collaborative
o activities.
According to Elias,
one of the highlights of
of Fynbos the exhibit will be the
fan (second introduction of potted
national bulbs of a new Orni-
thogalum. It was devel-
oped and named by re-
searchers at the ARC Fynbos (pro-
nounced FINN-bose) Unit near Cape
Town. These plants will be brought
from South Africa by a contingent of
the country's representatives.
"South Africa is noted for its
tremendous diversity and richness of
flowering plants-like nowhere else


Binational Cooperation Yields a Wealth of New

Blooms for America's Markets

Agricultural Research/September 1997

The 70th anniversary celebration of the U.S. National Arboretum highlights plants

from South Africa.

on the planet," says Elias. "It's
especially rich in an assortment of
bulb plants such as gladiolus and
amaryllis. Several South African
plants well known to U.S. garden-
ers-members of the genera Ger-
bera, Sansevieria, Aloe, and Plumba-
go-will be featured in the exhibit."

Unusually Varied Flora
Although South Africa occupies
less than 1 percent of the world's
land mass, it contains 10 percent of
all the Earth's species of plants. In an
area smaller than Ver-
mont, the so-called Cape
Floral Kingdom hosts
more than 8,600 plant
species, 5,800 of which
are unique to the area.
South Africa has a
third of the world's
succulent plant species,
over 2,000 Mesembryan-
themaceae species, and

more than 100 Pelargonium (gerani-
um) species.
"The South African exhibit will
feature plants that show the area's
unique diversity and richness of
flowering plants," says Elias. "Espe-
cially interesting is the incredible
assortment of exotic bulb plants. Many
are virtually unknown to U.S. growers,
nurseries, and consumers."
According to Ruxton H. Villet, ARS
Deputy Assistant Administrator for
international programs, "In 1995, nine
animal and plant projects with South
Africa were implemented by ARS and

funded by the U.S. Agency for
International Development. Their
objective is to develop small-scale
farming with high-value agriproducts
that could lead to small business
enterprise in rural areas. Ornamental
plants is one area of focus."
This year, ARS will begin a
cooperative project with South Africa
to develop and introduce these many
new plants to U.S. consumers.
The project's mission:
Identify high-potential plants for
cooperative research with South
African scientists;
Develop them as
new ornamentals and cut

"What's disconcerting," says
Elias, "is that about 1,700 of the
8,600 flowering plants indigenous to
the Cape are listed as being critically
rare, endangered, or vulnerable. An
appalling 29 of these are known to
have already become extinct." This
loss is the result of alien plant
invasion, uncontrolled fires, injudi-
cious flower picking-as well as
agricultural and urban expansion.
But because of the great variety of
plants and animals found in South
Africa, important
segments have
been protected by
an extensive
national park
system and
Visitors to the
arboretum exhibit
will discover the
seven major types
of ecological

communities, or biomes, in South
Africa. They are forest, thicket,
grassland, savanna, nama karoo,
succulent karoo, and the fynbos.
Much of the country's floral diversity
is found in the Cape region in the
fynbos (Dutch for fine-leafed plants)

A Magical, Botanical Land
The Cape Floral Kingdom, or
Fynbos, contains an exceptionally

diverse and biologically unique
flora. The Fynbos comprises about
17,000 square miles of the southern
and southwestern Cape. It is located
at the southernmost tip of Africa,
where the Indian and Atlantic
Oceans meet.
The Cape Floral Kingdom is both
the smallest and richest floral
kingdom, with the highest known
concentration of plant species-
about 1,300 per 4,000 square miles.
Its nearest rival, the South American
rain forest, has a
ARC FYNBOS UNIT concentration of
only 400 plants
per 4,000 square
miles. The total
world range of
some of these
plant species is
an area smaller
than half a
soccer field.
vegetation is an
unusual mixture

of plant types of different shapes
and sizes, though trees are rare in
natural fynbos. Four plant growth
types occur: tall protea shrubs with
large leaves, called proteoids;
heathlike shrubs, the ericoids;
wiry, reedlike plants, called
restioids; and bulbous herbs, or
The abundant ericoids comprise
more than 3,000 species, including
the 627 different species of the
Erica family. Erica species are
used in the international horticul-
tural trade as potted plants. Currently
in South Africa, Ericas are harvested
only in the wild for the cut flower
ARS and ARC will begin a 3-year
study in 1998 to develop new potted
plants of Erica species, Elias says.
Restioids, members of the Res-
tionaceae family, resemble reeds or
rushes and consist of 310 species that
include Elegia (32 species). Potted
plants of this interesting South
African family will be part of the

King Protea, Protea cynaroides, the
national flower of South Africa.

Bird of Paradise, one of South Africa's many
contributions to the ornamental nursery and
floral industries.

arboretum exhibit. "These plants are
a new substitute for ornamental
grasses," says Elias.
South Africa has the richest
geophyte flora in the world. It is
home to over 2,000 flowering bulb
species, of which more than 1,400 are
found in the Cape Floral Kingdom.
Many of these bulbous species have
been collected by visiting botanists
and then cultivated in foreign coun-
tries. They include some of the most
popular bulbous plants in the world,

Aloe growing in the wild in the
Drakensberg Mountains of South Africa.

belonging to genera like Freesia
(iris family), Nerine (amaryllis
family), and Gladiolus.
Elias says that South Africa has
96 of the 160 Gladiolus species
found throughout the world. "The
country also boasts 88 recorded
species of the lily Lachenalia, out
of an estimated world total of 110.
Several examples of new Lachena-
lia hybrids developed by the ARC-
Roodeplaat in Pretoria will be
displayed at the arboretum," says

A Boon to Small Growers
Realizing the inherent potential of
small-scale floriculture farming to
improve the economic situation of
previously disadvantaged people,
ARC has redirected the focus of its
Fynbos Unit. "This unit has taken the
lead in applying science, together
with economics and community
development, to form a comprehen-
sive regional approach to conserva-
tion," says Villet.


Red pincushion protea, Leucospermum

Agricultural Research/September 1997

Flowers most commonly associat-
ed with the Fynbos are proteas. Aptly
named after the Greek god Proteus,
who could assume many different
forms at will, proteas come in many
shapes and sizes.
Native to the southern hemisphere,
the proteas found in South Africa
number about half of those found in
the world. The curious diversity in
form and color of the Proteaceae is
evident in the majestic King Protea,
P. cynaroides, which is the South
African floral emblem; the delicate
Blushing Bride, Serruria; the fasci-
nating Pincushions, Leucospermum;
and the Cone Bushes, Leucadendron.
"The flowers and fruits of certain
proteas are attractive and unusual in
form and color, making them ideal
for fresh or dried flowers and for use
in artistic arrangements," says Elias.
In all, South Africa has 15 indige-
nous genera and more than 400 spe-
cies. Over 50 different cultivated


forms of proteas will be featured in
the arboretum exhibit.
Says Villet, "South Africa's di-
verse and beautiful groups of flower-
ing plants can bring excellent prices
in international markets. But there
are problems.
"The wildflower industry in the
western Cape has a long history.
Fresh and dried flowers, valued at
about $20 million a year, are export-
ed annually to Europe and the East
and involve about 20,000 people de-
pendent on the industry. But since
flowers are still largely picked from
plants in the natural habitat, this ulti-
mately has a negative environmental
effect," says Villet. "And the product
rarely meets the stringent quality re-
quirements for global markets."
So ARS, in collaboration with the
ARC Fynbos Unit, is working to co-
develop technologies that will permit
establishment of cultivation systems
leading to high productivity and qual-

Spring wildflowers bloom along the Cape
of Good Hope coast near Cape Town,
South Africa.

ity that meet exacting standards re-
quired for international trading.
The unit has set up well-organized
programs to train small farmers. It
also has an active research and devel-
opment program to boost the indus-
try. The collaboration with ARS will
lead to new cultivars, new links with
U.S. industry, and environmentally


Leucadenaron, an indigenous member of
the Protea family.

Watsonia, a common bulbous herb.

Agricultural Research/September 1997

satisfactory farming operations in
South Africa, says Villet.
"It is important to have an effi-
cient chain of operations-from pro-
duction to processing and from pack-
aging to marketing. The Fynbos Unit
provides expertise and guidance in
production and processing; the small
farmers have taken the responsibility
on themselves for marketing their at-
tractive products," he says.

And We Gain, Too
Elias says the South African coop-
erative research program is "another
step in the arboretum's mission; that
is, to develop and implement new and
innovative technologies for U.S. flo-
ral and nursery industries-to keep
them competitive in world markets."
Over the years, the arboretum has
genetically improved major cut flow-
ers and flowering plants, including
carnations, chrysanthemums, glad-

ioli, hydrangeas, irises, lilies, poinset-
tias, roses, and many other plants.
"During the last 10 years, the labo-
ratory has developed several new re-
search programs involving both basic
and applied research to improve floral
crops," says Elias. "The result has
been development of many new tech-
nologies in tissue culture, biotechnol-
ogy, and entomology-as well as new
floral and nursery plants.-By Hank
Becker, ARS.
Thomas S. Elias is at the USDA-
ARS U.S. National Arboretum, 3501
New York Ave., NE, Washington,
D.C. 20002; phone 202-245-4539, fax
202-245-4574, e-mail telias@ars-
Ruxton H. Villet is at the USDA-
ARS Beltsville Agricultural Research
Center, Bldg. 005, 10300 Baltimore
Ave., Beltsville, MD 20705-2350;
phone 301-504-5605, fax 301-504-
5298, e-mail *

Cooperation Begins at
Highest Levels
Research cooperation between
the Agricultural Research Service
and its South African counter-
part, the Agricultural Research
Council, had its beginnings in a
U.S.-Republic of South Africa
Binational Commission that Vice
President Al Gore and South
African Deputy President Thabo
Mbeki signed into being in 1994.
The agreement provided a
framework to facilitate collabora-
tion in business development,
energy, the environment, human
resources and education, and
science and technology that
would be of benefit to both
countries and help enhance the
stability of democracy in South
Africa. Agriculture was added as
a specific focus in 1995.
Exchanges of scientists,
coordinated research projects,
joint seminars, shared research
facilities, and other partnerships
between ARS and ARC are all
encouraged under the Binational
Commission. Current projects
include commercialization of
indigenous goat farming prod-
ucts, developing high-value
indigenous ornamental plants,
and enhancing earnings for
small-scale farming.
Other partnerships have been
created to help enhance small-
scale farming ber~ween ARS and
other South African institutions
including universities, small farm
cooperatives, and local business-
es, as well as the Ministry of
Agriculture and Land Develop-
ment. Many projects involve
developing high-value products
such as novel biopesticides for
sustainable agriculture.

Angus surrogate mother nur
the influence of surrogate br
weaning weights.

F ive years of research were on
the line, and Agricultural
Research Service physiolo-
gist Chad Chase was nervous. A
Venezuelan national guardsman said
he needed to inspect Chase's cannis-
ter of cryo-preserved Romosinuano
cattle embryos before the scientist
could board a flight back to Florida.
Inspection would mean death for the
Chase, a Venezuelan colleague,
and a veterinarian with USDA's
Animal and Plant Health Inspection
Service tried to explain this, but the
guard was firm.
The veterinarian had put special
seals on the canisters to prove they
would not bring disease into the
United States. And he'd told ARS'
Chad Chase that if the seals were
broken, the embryos would have to
be destroyed.
The travelers decided to put off
their flight-until the next day.
But the next day was worse. The
guard on duty then wanted to use an
X-ray as an alternative to opening the
canister. The X-ray could deform the
embryos. Unfortunately, Chase

ses her Romosinuano embryo transfer calf. Initially, scientists are investigating
eed on Romosinuano calf traits such as length of gestation and birth and

couldn't argue; he was told to
proceed to the boarding gate.
His colleague, Venezuelan profes-
sor Jorge Beltran of the University of
Central Venezuela at Maracay,
stayed behind, calmly explaining the
situation to the guard and producing
documentation to prove the "Vapor-
Shippers" held cattle, not contraband.
Finally, the guard relented.
Today, 67 Romosinuano calves
with a big future enjoy life at the
ARS Subtropical Agricultural
Research Station in Brooksville,
Florida. They owe their lives in part
to the professor's ability to keep cool
under pressure.
"I was very persistent. I think
that's what saved us," says Beltran,
who heads his university's cattle
breeding and genetics program. "The
final call for boarding came and they
were still held up at the gate, but I
just kept talking. I think that's what
finally made the guard give up."
"I was relieved when I saw the
canisters with their seals unbroken at
air cargo pickup in Miami," says
Chase. It wasn't the first time, he
says, that he had relied on Beltran to

solve problems. The professor had
laid much of the groundwork for get-
ting the embryos to the United States.
"To me, it was exciting to see so
many people working on this collabo-
rative USDA project. We all worked
together; there were no stars," says
Beltran. "It opens new opportunities
in cooperative research."
The Romosinuano project was the
brainchild of animal scientists
Andrew C. Hammond and Timothy
A. Olson. Hammond heads the
Brooksville lab where Chase works,
and Olson is a professor of animal
breeding at the University of Florida
at Gainesville. They made the initial
visits to Costa Rica and Venezuela to
evaluate the breed's potential.
Their plan was to give the South-
east an animal with improved temper-
ament, good heat and pest tolerance,
and early maturation. Brahman cattle,
often favored in the Southeast, offer
heat and disease tolerance, but their
temperament and meat quality vary.
They also raise a farmer's overhead
by taking longer to reproduce.
Beltran had done a sabbatical with
Olson and Hammond. And he knew

Agricultural Research/September 1997

Romosinuano breeder Carlos Rod-
riguez, also from Venezuela, which
made him a natural contact.
"It's the breeders and ranchers we
need to thank," says Chase. "Caracci-
olo Carrero, president of ASORO-
MO, the Romosinuano breeders'
association in Venezuela, and his
colleagues, Carlos Rodriguez, Luis
Mantilla, and Valmore Sanchez-
they made this possible; they encour-
aged us."
And encouragement was needed.
Romosinuanos are native to Colom-
bia, but civil strife there had halved
the number of animals surviving
since 1987. Many survivors were sent
to Venezuela. But getting embryos
from there also required disease
In Venezuela, there were nearly
500 purebred Romosinuanos owned
by five breeders. But there was
something else there, too: foot-and-
mouth disease, a virus that causes
painful sores on livestock's feet and
mouths, making them stop eating and
sometimes killing them. Controlling
even a modest U.S. outbreak could
cost more than $50 million, accord-
ing to APHIS.
Foot-and mouth disease has been
eradicated in the United States. The
last outbreak was in 1929. Congress,
in 1950, made it unlawful to possess
live foot-and-mouth virus on the U.S.
mainland-even in the form of
vaccines. Study of the disease here is
restricted to USDA's Foreign Animal
Disease Laboratory at Plum Island,
New York.
Importing embryos from countries
where the virus was endemic was
illegal before 1991. But APHIS
designed special protocols for legal,
disease-free importation of bovine
embryos. Agency veterinarians tested
donor animals' body fluids, such as
blood and the uterine fluid expelled
when embryos were collected.

Agricultural Research/September 1997

To further guard against infection,
APHIS required all embryo transfer
equipment to come from the United
States. Meeting this mandate proved
challenging when airline embargoes
caused shipping delays.
Chase and his team also gave the
embryos a special washing treatment
required by law to guard against
infection. After washing, the leftover
solution was tested for traces of foot-
and-mouth virus.
qr.nTT RAIIR f7R11-171

Senopol surrogate mother with
Romosinuano embryo transfer calf. A
tropically adapted breed from the
Caribbean, Senopols are increasingly
popular throughout warmer U.S. regions.

APHIS veterinarian David Vogt
also inspected the Venezuelan
university's facility. It is in a valley
isolated by mountains, so no other
cattle herds could come in contact
with the parent animals. The self-
contained center has barns, labora-
tories, and a housing complex for the
Why all the effort? This project is
probably the only chance U.S.
researchers will have to fully evaluate
this breed. Foot-and-mouth-disease-
free Costa Rica has Romosinuanos.
In fact, Chase and his colleagues
have raised a herd from Costa Rican
embryos collected by University of
Missouri researchers in 1990 and
1992. But these animals aren't pure
Romosinuanos, so they don't tell

much about Romosinuanos' true
A purebred Colombian Romosinu-
ano, however, must be paid for with
lots of planning and discussion.
Many scientists, both in the United
States and Venezuela, brought their
expertise to the project. Ron Randel,
a researcher with Texas A&M
University, served as a consultant.
Geneticist Larry V. Cundiff from
ARS' Roman L. Hruska U.S. Meat
Animal Research Center in Clay
Center, Nebraska, accompanied
Chase and Olson to help pick the
Romosinuano parents. A total of
eight Romosinuano families were
included in the project to ensure
genetic diversity of the U.S. Ro-
mosinuano herd.
Chase says credit also goes to
embryo transfer specialists, Jim
Griffin of Reproductive Technology
International in Plant City, Florida,
and to Clifton Murphy, a veterinarian
from the University of Missouri who
flew to Venezuela to meet Chase and
collect the embryos. Reproductive
physiologists Juan Troconiz and
Pedro Bastidas from the University
of Central Venezuela in Maracay
also cooperated, he says.
"That's what scared me about the
national guardsman at the airport,"
says Beltran. "So many people gave
so much to make this project a
success, and just one person could
have undone everything."
"We did have some difficult
situations, but ultimately we were
successful," says Chase. "It's been a
fantastic group effort." -By Jill
Lee, ARS.
Chad C. Chase, Jr., and Andrew
C. Hammond are at the USDA-ARS
Subtropical Agricultural Research
Station, 22271 Chinsegut Hill Rd.,
Brooksville, FL 34601-4672; phone
(352-796-3385, fax (352) 796-2930,
e-mail [Chase]
[Hammondlach@ *

Reviving Trap Cropping

Melon growers' next battle cry

against insect pests could be

Squash 'em!

Once warmed by spring's arrival,
cucumber beetles and squash bugs
are soon on the move.
They are looking to feast SCOTT BAUER (K7765-1
on the tender seedlings
of watermelon or other
cucurbits, like canta-
loupe. This can put mel-
on growers on the defen-
sive, forcing them to
blanket their crop fields
with insecticide. Cucumber beet
But some growers in
central Texas and south-
central Oklahoma are taking a differ-
ent tack. Rather than resort to broad-
cast spraying, they're "squashing"
their beetle and bug foes instead.
Yes, squashing them-and also
saving on insecticides and beneficial
insects like the lacewing. But grow-
ers don't use their bootheels to do the
job. Instead, they follow the direction
of ARS entomologist Sam D. Pair.
His advice: Line the edge of the
melon field with a few rows of
squash-the beetles' and the bugs'
cucurbit crop of choice.
This integrated approach to pest
management does three things, says
Pair, who is at ARS' South Central
Agricultural Research Laboratory in
Lane, Oklahoma.
It lures hungry insects away from
melon seedlings, leaving them to
grow, unmolested, into fruit-bearing
plants. It encourages the insects to
congregate on squash plants, where a
judicial application of insecticide can
kill them. And it eliminates the need
to spray the entire field.
"If we can concentrate insect pests
early in the season in a preferred host
crop and control them there," Pair ex-

plains, "then we can also reduce the
late-season buildup of insect off-
spring in the primary
crop at its fruiting stage."
This tactic is called
trap cropping. Its
strength lies in a key
weakness of the insect
pests: an inherent prefer-
ence for squash over wa-
termelon or cantaloupe.
le. What, precisely, attracts
the insects to squash isn't
known. Scientists have
yet to pin down whether it's the scent
of the plant, its size or color, nutri-
tional content, or possibly a combina-
tion of all these traits.
Whatever the attraction, Pair has
sought to make it fatal.
In field studies with melon, the
squash lured more than 66 percent of
cucumber beetles and 90
percent of squash bugs. A
single application of either a
systemic or foliar insecticide
spelled doom for those
drawn to the treated squash
"Normally the squash at-
tracts enough of the popula-
tion that what's left in the
melon crop is not a prob- Squash
lem," Pair notes.
Bob Whitney, a Texas A&M Uni-
versity extension agent in Comanche
County, Texas, reports excellent re-
sults from five producers who used
the approach last year against cucum-
ber beetles.
The 1/4-inch-long pest jeopardizes
some 10,000 to 12,000 acres of mel-
ons grown in Comanche, located
about 200 miles north of San Anto-

nio. Whitney says that depending on
the type of insecticide, melon grow-
ers can spend $10 to $40 per acre on
active ingredient, with about a $4 ap-
plication fee attached. The cost of
spraying a 100-acre field just once,
for example, could range between
$1,400 and $4,400.
During the course of the growing
season, melon producers may resort
to insecticide as many as three or
four times, or whenever scouting de-
tects one beetle for every four or five
plants. But with squash as a beetle
decoy, "there's no need to have an in-
secticide in the melon crop at all,"
Whitney says. May and June are the
months the beetle is most trouble-
some. "That's when we plant a lot of
melons," says Whitney, who suggests
transplanting squash 3 to 7 days be-
fore melon.
ER (K7763-1) Left-un-
checked, cucum-
ber beetles can
wipe out an entire
seedling stand.
In Comanche
County, the
squash bug is less
of a problem. But
its mischief can't
bug. be ignored either,
particularly since
it breeds prolifically. The 3/4-inch-
long bug sucks juices from both seed-
lings and fruit-bearing plants. It can
also compound plant stress, such as
that caused by drought.
Often, a systemic insecticide is
called on. "But we don't like to use
those," says Whitney. "The few that
we have that are good for cucumber
beetles and squash bugs are harsh and

Agricultural Research/September 1997



Entomologist Sam Pair inspects squash plants for cucumber beetles and squash bugs
lured to this trap crop and away from developing melons.

require special precautions so grow-
ers can use them."
That's also a concern of producer
Mark Weatherly, who grows 350 to-
tal acres of melon in Love County,
Oklahoma. He's in his second season
of using squash trap crops.
Unlike Comanche County grow-
ers, his chief concern is the squash
bug. Because his field is subject to
wind-driven assaults, Weatherly
plans to bolster his squash defenses
with additional rows. "I'd like to
plant some rows in the middle of the
field," he says.
Last year, wind-blown bugs land-
ing in the melon crop, coupled with a
lack of adequate squash rows, forced
Weatherly to spray one of his fields.
Armed with his new squash defense,
"I'm going to try it again and see," he

Great for Beneficials
Besides cutting back on acreage
that requires chemical protection, a
squash trap crop can offer another
benefit: grant predatory insects like

Agricultural Research/September 1997

lacewings a new lease on life. Minus
insecticide, they can prowl crop
fields for secondary pests like aphids,
which can flourish in the absence of
bug or beetle competitors.
"When the fields are without in-
secticides, lacewings and ladybugs
just go crazy," Whitney says. "This
has helped keep our aphids in check."
Pair and plant pathologist Benny
D. Bruton see another benefit: pro-
tecting melons from cucumber beetles
that harbor Erwinia tracheiphila, the
organism that causes bacterial wilt.
"If you can reduce the number of
beetles carrying this bacterium," says
Pair, "you should be able to reduce
the incidence of the disease in the
main crop."
This would probably benefit grow-
ers of the Midwest or mid-Atlantic
states like Maryland, he says, where
the wilt generally poses more of a
melon threat than in the Southern
Other than curbing beetle-borne
disease, "We're looking at using trap
cropping as a management strategy

against the insect vector of yellow
vine decline," Pair says.
He and Bruton are investigating
whether squash can attract the mys-
tery insect that spreads this disease
before it finds its way into the melon
crop. One suspect is the leaf hopper,
which can pass along disease-causing
microbes as it probes plant tissues to
Whatever the culprit, what worries
growers like Rodney Stephens of
Comanche County is that yellow vine
decline "can take out the whole field
Over the past 4 years, Stephens'
crops have remained unscathed, but
he's still uncertain whether to credit
the squash around his fields. "We
haven't seen it when using squash for
trap cropping, but we also haven't
seen [the disease] without it," says
Stephens, who grows 50 to 100 acres
of melon each season.
Stephens plans to continue his
squash trap crops. "One of the things
I like is a little different source of
income with squash," he says. And
"if it helps keep insects out of my
melons, then I'm getting a double
Key to this is selecting a high-
yielding squash variety and keeping it
well-watered and fertilized. Scouting
for insect activity is also important to
prevent migration into the melon
Pair hopes to capitalize on
squash's success further with other
tactics. One is using colored plastic
mulch, either as a repellent or added
attractant to further tempt beetles or
bugs into being "squashed."-By Jan
Suszkiw, ARS.
Sam D. Pair and Benny D. Bruton
are at the USDA-ARS South Central
Agricultural Research Laboratory,
P.O. Box 159A, Lane, OK 74555;
phone (405) 889-7395, fax (405) 889-
5783, e-mail *


- -*~ ~



Stopping Erosion With Gypsum and PAM

I n the late 1700s, Benjamin
Franklin, whose interest in
scientific experiments is now
legend, demonstrated the value of a
natural geological substance called
gypsum, used in making plaster, as a
soil amendment.
On a prominent hillside, Franklin
applied gypsum in a word pattern that
read, "This land has been plastered."
The increased grass growth in the
area on which the gypsum had been
applied served as an effective demon-
stration of its value as a fertilizer.
Two hundred years later, gypsum
is again being studied-this time as a
way of controlling erosion by in-
creasing water infiltration.
"New technologies to improve KEIT
air quality have produced more
and more gypsum byproducts
with potential for beneficial use
in agriculture," says ARS soil
scientist L. Darrell Norton. He is
at the National Soil Erosion
Research Laboratory (NSERL) in
West Lafayette, Indiana. "The
removal of sulfur from flue gases
in coal-fired power plants has
resulted in immense stockpiles of
these byproducts that can supply
sulfur to crops and may also So
serve as a liming agent." W(
"Each year, power plants pro- of
duce about 100 million tons of
gypsiferous material, high in cal-
cium and sulfur, as a byproduct of
capturing sulfur dioxide emissions,"
says W. Doral Kemper, who formerly
led the ARS national program in soil
management research. "That's
enough to apply a ton per acre to a
quarter of U.S. farmland."
Norton and Kemper believe that
recycling these low-cost byproducts
of industry to control erosion and
increase yield is a win-win situation.
They say gypsum can be used on
many soils nationwide to improve
water infiltration and help plant

Agricultural Research/September 1997

The two believe the increased
yields are explained by studies
conducted by ARS soil scientists K.
Dale Ritchey at Beaver, West Virgin-
ia, and Ronald F. Korcak at Belts-
ville, Maryland, and their coworkers.
These studies have shown that
calcium from gypsum applied to
acidic soils gets down into the
subsoil where it is needed, so crop
roots can grow deeper and access
more water.
Norton says, "Using gypsiferous
byproducts would give farmers a
low-cost remedy for acid, sodic, and
erosion-prone soils."

H WELLER (K7755-2)

il scientist Darrell Norton (left) and Ralph
oodward, a cooperating corn farmer, assess the effe
field application of gypsum on plant root growth.

Several years ago, ARS scientists
at the NSERL worked with world-
renowned soil scientist Isaac
Shainberg, who is now director of the
Volcani Institute in Israel. They
wanted to determine how electro-
lytes, which are natural electrical
conductors in rainfall and runoff
water, could affect estimates of soil
erodibility. During Shainberg's visit,
the idea of using gypsum and other
soil amendments to control soil
erosion by water from agricultural
fields was also discussed.

"We suspected that gypsum could
reduce surface sealing and improve
water entry and reduce erosion," says
Norton. "In lab studies, we found the
powdered waste product releases
electrolytes that keep clay particles
clumped together, reducing crusting."
About the same time, Shainberg
became interested in another white
powder-PAM, short for polyacryla-
mide-a material used in water
treatment plants as a flocculent to
clean up the water by precipitating
small particles.
"According to the literature, you
could stabilize a soil with PAM, but it
was very expensive for practical use
when mixed in the entire
plowed layer," says Norton. A
series of lab studies conducted
by Shainberg and ARS scien-
tists on some small flumes
confirmed that as little as 5 to
10 parts per million of PAM
mixed with water almost
eliminated rill erosion-the
tiny gullies caused by water
moving over the soil.
At the NSERL, Norton and
S Shainberg, working with three
ki ARS colleagues-soil micro-
biologist Diane E. Stott,
ct agricultural engineer John M.
Laflen, and soil scientist Joe
M. Bradford-studied how
adding PAM both to simulated
rainfall water and to the soil surface
affected erosion. They soon came to
recognize that if the soil surface
could be stabilized down to just a
very small depth, erosion might be
greatly reduced.
"Most important," says Norton,
"was the finding that PAM didn't have
to be mixed into the soil. Only the sur-
face layer-less than the top one-six-
teenth inch or less of soil-has to be
treated, to let water into the soil."
NSERL agricultural engineer
Dennis C. Flanagan, working with
Norton and Shainberg, conducted

field tests to examine how effective
both gypsum and PAM could be at
controlling soil loss on a steep and
erodible silt loam soil. They tested
surface applications of 2.2 tons per
acre of gypsiferous byproduct from
the Purdue University power plant in
West Lafayette, Indiana, as well as a
liquid solution of 18 pounds per acre
of PAM sprayed on the soil and
allowed to dry.
They found that the byproduct
improved infiltration and could
potentially reduce runoff and erosion
problems on similar U.S. soils. The
PAM surface treatment was very
effective at controlling rill erosion,
even for water inflows up to 16
gallons per minute per rill.
"PAM is a polymer produced from
petrochemicals," says Stott. Efforts
are under way with ARS researchers
at the National Center for Agricultural
Utilization Research in Peoria,
Illinois, to develop a cheaper, starch-
based copolymer.
Stott and ARS soil scientist Rod-
rick D. Lentz at Kimberly, Idaho,
have tested many commercial syn-
thetic PAM forms to pinpoint desir-
able characteristics. So far, they've
found some types of PAM materials
work better than others to reduce
crusting, increase water infiltration,
and promote seedling emergence.
NSERL lab experiments in 1992
showed that gypsum byproducts
tested on three soils, using simulated
rainfall, produced some valuable
results. A byproduct of almost pure
gypsum from a special coal-burning
technique in power plants increased
water infiltration and reduced soil loss
by about one-fourth. A type of
gypsum left over from fertilizer
manufacturing did almost as well in
reducing soil loss between rows.
Other related work at NSERL
includes the blending of several
byproducts like fly ash and organic-
rich industrial sludge. This appears

Samples of runoff water examined by soil scientist Darrell Norton were collected from
an experimental plot in farmer Ralph Wood's gypsum-treated cornfield in Carlisle,

very promising, says Norton, in
producing a high-organic-matter,
high-nitrogen, and high-phosphorus,
soil-like material that is environmen-
tally friendly.
This work has been done coopera-
tively with Purdue researchers and
has received funding from several
Indiana sources-the Eli Lilly
Company, Lafayette; Purdue Univer-
sity power plant, West Lafayette;
Amax Coal Company, Brazil; and the
Indiana Department of Commerce,
Now that Norton and NSERL
scientists have documented some of
the chemical, physical, and biological
processes that occur on soils that
have gypsum applied, they are
currently studying the effects on crop
Cooperating farmers report
encouraging results. In one of over
50,000 acres of field tests, Ken Curtis
of Prairie City, Illinois, used high-
purity gypsum, a scrubber byproduct
from a coal-fired unit of City Water,
Light, and Power of Springfield,
Illinois. He applied 3 tons of gypsum
per acre to a 20-acre field of no-till
soybeans, randomly applying various
"Treated soybeans yielded 63
bushels per acre-4 bushels more
than the nongypsum control. I didn't
expect that much response so quick-
ly," says Curtis.

Norton plans to expand the test
acreage to further assess benefits of
gypsum on wheat, corn, and soy-
beans in several eastern states.-By
Hank Becker, ARS.
L. Darrell Norton is at the USDA-
ARS National Soil Erosion Research
Laboratory, 1196 Soil Bldg., Purdue
University, West Lafayette, IN 47907-
1196; phone (765) 494-8682, fax
(765) 494-5948, e-mail *

Adding a tracer dye enables graduate
student Katerina Dontsova to measure the
velocity of water flowing across an
experimental plot.

Agricultural Research/September 1997

PAM Keeps Soil in

Its Place

Water that rushes down irrigation furrows on

western farmlands takes little if any topsoil
with it if an erosion-fighting white powder is
mixed in. An ounce of the synthetic compound-called
polyacrylamide, or PAM for short-helps anchor as much
as 1,000 pounds of topsoil that might otherwise be swept
away by irrigation water.
Extensive outdoor tests during the past 6 years by ARS
scientists based at Kimberly, Idaho, have shown western
U.S. growers and state regulatory agencies that water-
soluble, negatively charged polyacrylamides are a safe,
convenient weapon for fighting erosion on furrow-
irrigated farmlands.
"Growers tell us," says ARS soil scientist Rodrick D.
Lentz, "that PAM-treated water leaving their furrows is
often cleaner than when it came in." Lentz is with the
ARS Northwest Irrigation and Soils Research Laboratory
at Kimberly.
And data from experiments by Lentz and Robert E.
Sojka, who is also at Kimberly, have proven that small
doses of PAM can boost infiltration by as much as 60
percent. That saves water.
The ARS team's careful determinations of what kind
of PAM to use and when, where, how, and how much to
add to irrigation water contributed to USDA Natural
Resources Conservation Service's recent decision in
some states to approve PAM's use as a conservation prac-
tice. And the ARS findings were instrumental in garner-
ing, within the past 3 years, regulatory approval from 13
western states for agricultural use of the chemical.
What's more, increased use of PAM on western farms
has led four innovative businesses to begin manufacturing
equipment designed especially for adding precise
amounts of PAM to irrigation water at the top, or head, of
the irrigation furrow.
Too, the Idaho scientists landed a cooperative research
and development agreement with Cytec Industries, a
Stamford, Connecticut, maker of polyacrylamides for
farms, water purification plants, and other markets. The
collaboration included experiments with a new test that
researchers Lentz, Sojka, and James A. Foerster at
Kimberly developed to measure leftover polyacrylamide
in water that leaves the end of the furrows after use,
called tailwater.
Faster and simpler to use than many other techniques,
the test has shown that more than 99 percent of the
applied PAM remains-appropriately-on treated fields
to biodegrade. This result holds true if growers apply the
prescribed rate of 10 parts per million-that is, a table-
spoon of PAM for every 750 gallons of irrigation water

Soil scientists Robert Sojka (left) and Rodrick Lentz check for
PAM residues in water running off furrow-irrigated fields.
Almost all the PAM applied to fields stays in place and eventually

until the first of this water reaches the end of the furrow.
Another research spin-off: Lentz created a software
package called WASHOUT to quickly estimate the
amount of sediment in irrigation runoff, based on mea-
surements from small samples of tailwater. Says Lentz,
"You could also use this software to monitor other
components that wash out of furrows when they're
irrigated, like nutrients or pesticides."
For their research, Lentz and Sojka won a 1996
technology transfer award from the International Erosion
Control Association. The group credited the team with
opening the door to use of PAM to thwart erosion on
more than 50,000 acres of farmland in 1995. That pre-
vented some 1 million tons of topsoil from eroding. A
more recent industry estimate places on-farm use for
1996 at about 400,000 acres.-By Marcia Wood, ARS.
Robert E. Sojka and Rodrick D. Lentz are at the
USDA-ARS Northwest Irrigation and Soils Research
Laboratory, 3793 N. 3600 E., Kimberly, ID 83341; phone
(208) 423-5582, fax (208) 423-6555, e-mail
Visit the PAM site at
pampage.htp *

Agricultural Research/September 1997

Helping Cereals Resist Head Scab Steadfast Trefoil's a Survivor

Head scab annually causes millions of dollars' worth
of losses in wheat, rye, barley, and other cereal crops in
the Great Plains and Midwest.
All this damage is caused by the fungus Fusarium
graminearum, which got nicknamed "head scab" because
of the blisters or scabs it forms on the grain-bearing
structure, or head, of grain plants.
The disease is cyclical, severely infecting crops one
year and then disappearing for several years before
reappearing again. A recurrence of severe infestations of
head scab across the Great Plains and Midwest in recent
years has sent plant breeders and researchers scrambling
for new ways to combat the disease.
Plant breeders typically attempt to reinforce cereal
crop defenses by breeding for greater resistance to the
fungus. Thomas M. Hohn, a microbiologist in the ARS
Mycotoxin Research Unit at Peoria, Illinois, says he and
colleagues decided to look for the genetic equivalent of
an Achilles's heel in the fungus
SUSAN MCCORMICK and found it.
They have successfully
disarmed the fungus' ability to
produce its toxin, tricho-
thecene, by identifying the
gene that is responsible for the
production of an enzyme,
trichodiene synthase.
This enzyme enables the
fungus to produce tricho-
thecene. Scientists at the lab
disabled the toxin-producing
gene and were able to success-
Premature bleaching of fully demonstrate that the
wheat infected with genetically altered fungus was
Fusarium graminearum is less damaging to crops.
a typical symptom of head ARS scientists say this new
scab. knowledge of the importance
of toxin production by the
fungus will give wheat breeders more ammunition for
fighting costly head scab.
"We know disease resistance in wheat and barley is
based on several factors and that current wheat breeding
strategies provide only partial resistance," says Hohn.
"We believe our findings linking toxin production with
the amount of disease caused by the fungus may be
another tool for wheat breeders to use in combating this
disease."-By Dawn Lyons-Johnson, ARS.
Thomas M. Hohn is in the USDA-ARS Mycotoxin
Research Unit, National Center for Agricultural Utiliza-
tion Research, 1815 N. University St., Peoria, IL 610604;
phone (309) 681-6380, fax (309) 681-6665, e-mail *

The first commercial variety of birdsfoot trefoil in the
world with both the ability to spread and to resist root
diseases is now available.
Birdsfoot trefoil is a fine-stemmed, yellow-flowered
forage crop that resembles alfalfa; but it tolerates poor
soil conditions and abuse from grazing animals much
better than alfalfa. It is palatable to animals, nutritious,
and doesn't cause bloating that animals can get from
other legumes.
"Steadfast is a fitting name for the new variety,
because its ability to spread by rhizomes helps plants
keep from being killed by root diseases that normally
plague trefoil varieties," says Paul R. Beuselinck, an
ARS plant geneticist.
In Morocco, in the late 1980s, Beuselinck discovered
wild birdsfoot trefoil that produces rhizomes-under-
ground runners that allow the plant to spread to new
sites. The Moroccan wild types he collected contributed
to the parentage of Steadfast, which was released jointly
by ARS and the University of Missouri in 1995.
Rhizomes occur below the soil and can root and make
new plants. Even if the original parts of the mother plant
die from disease, new plantlets that develop from rhi-
zomes allow the plant to survive and spread.
Root diseases have retarded the popularity of birdsfoot
trefoil in the United States. "Over time, stands of Ameri-
can varieties without rhizomes will likely thin out. But
stands of Steadfast, which has rhizomes, can be expected
to thicken, making more forage available for animals,"
says Beuselinck.
The variety should do well in areas of intensively
managed animal grazing systems for producers wanting a
nonbloating, cool-season legume as a component of their
grass-based pastures.
"Producers can use it on acres now planted only in
grass or that are considered unimproved," says
Peterson Seed Company, Inc., in Savage, Minnesota,
has obtained an exclusive license to sell and distribute
Steadfast.-By Linda Cooke, ARS.
Paul R. Beuselinck is in the USDA-ARS Plant Genet-
ics Research Unit, University of Missouri, 207 Waters
Hall, Columbia, MO 65211; phone (573) 882-6406, fax
(573) 882-1467, e-mail *

Agricultural Research/September 1997

Science Update

Let Us Eat Tastier Rice Cake
From 1992 to 1995. supermarket
sales of rice cakes, a healthful, fat-free
snack, rose from $157 million to near-
1 $S249 million. Improving their fla-
vor could win even more fans. Often,
manufacturers simply put a coating of
cheese or other flavor on the cake's
surface. While this works well for
thin, mini-size rice cakes, it doesn't
always provide uniform flavor in the
thicker, standard-size product. To
boost taste appeal, ARS scientists and
a manufacturer of organic rice prod-
ucts are devising a process for evenly
spreading the added flavors. The work
is being done under a cooperative re-
search and development agreement
(CRADA) between ARS and Wehah
Farm, Inc., of Richvale, California.
William J. Orts, USDA-ARS Western
Regional Research Center, Albany,
California, phone (510) 559-5730,

Silenced, Corn Genes May Speak
In the corn plant, genes orchestrate
flowering and other events that yield
an earful of fat, nutritious kernels. To
learn what part a given gene plays-
by silencing it-ARS scientists have
begun a new project. They are joining
with colleagues at Pioneer Hi-Bred In-
ternational, Inc., of Johnston, Iowa.
Under a CRADA, scientists hope to
discover functions of certain corn
genes. These are genes recently found

Geneticist Sara Hake checks experimental
corn for genetic change.

Agricultural Research/September 1997

bN researchers in California who are
with ARS and the University of Cali-
fornia. Their studies already reveal
that one of the genes tells a corn plant
how many flowers to make. It may
prove possible to restructure some of
the genes to boost yields or enhance
tomorrow's plants in other ways. The
ARS and UC scientists are using Pio-
neer Hi-Bred's "Trait Utility System
for Corn" to reveal what jobs the new-
ly discovered genes perform. TUSC
relies on a strategy called loss-of-
function. Through it, a selected gene
can be turned off in experimental
plants. Sarah C. Hake, USDA-ARS/
University of California at Berkeley
Plant Gene Expression Center, 800
Buchanan St., Albany, California,
phone (510) 559-5907, e-mail

Prettier Pea Soup
Split pea soups could be a deeper
green or a brighter yellow in a few
years. And farmers will benefit from
larger pea size and better disease re-
sistance from three new varieties of
dry peas. An ARS researcher devel-
oped and released the new varieties in
cooperation with Washington State
University and the University of Ida-
ho. Joel, a green dry pea, resists pow-
dery mildew and has greater yields
and larger seeds than popular varieties
now grown. It also keeps its dark
green color after cooking. Fallon and
Shawnee are yellow dry peas. They
have higher yields, larger seeds, and
better color than the industry stan-
dards. Fallon is semi-dwarf and semi-
leafless. The traits help plants stand
upright instead of falling over from
wind or rain. The semi-leafless trait
improves air circulation, reducing
dampness that favors some diseases.
Washington and Idaho produce most
of the nation's dry pea crop. About
two-thirds is exported to Europe and
Central and South America. For seed,
growers can contact the Washington

and Idaho state crop improvement as-
sociations. Fallon and Shawnee
should be available for the 1998
growing season and Joel in 1999. Fre-
derick J. Muehlbauer. USDA -ARS
Grain Legume Genetics and Physiolo-
gy Research Unit, Pullmanm, Washing-
ton, phone (509) 335-9521, e-mail

Elk Unaffected by Pine Toxin
Pregnant elk that eat Ponderosa
pine needles develop no reproductive
problems. This discovery by ARS sci-
entists could lead to ways to protect
pregnant cattle. University of Iowa
and Iowa State University researchers
collaborated in the study. Ponderosa
pines are common on grazing lands in
the West. Scientists and ranchers al-
ready knew the needles can be toxic if
eaten by pregnant cattle in the last tri-
mester. Blood flow to the uterus de-
clines, the cow delivers early, and
calves often die. By the most recent
estimate available, 1988, the problem
costs cattle ranchers some $20 million
annually. ARS scientists are testing
several ruminants including bison,
sheep, and goats to find ways to pre-
vent so-called "pine needle abortions"
in cattle. The scientists believe the
toxins are made harmless by natural
microorganisms in the elk's rumen
(the first of the four stomach compart-
ments in a ruminant mammal). Now
they are trying to determine differenc-
es between the natural microbial pop-
ulations of the elk and cow rumen. In
related studies, the university-ARS
team discovered and patented poten-
tially useful chemicals, waxy lipids,
in Ponderosa pine needles. The lipids
may have potential for treating post-
partum hemorrhages and other ail-
ments in people. Robert Short, USDA-
ARS Fort Keogh Livestock and Range
Research Laboratory, Miles City,
Montana, phone (406) 232-4970, fax
(406) 232-8209, e-mail
bshort@ larrl.ars.

U.S. Department of Agriculture
Agricultural Research Service
Room 408
6303 Ivy Lane
Greenbelt, MD 20770

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Using a bait made from wild
buffalo gourd root and carbaryl,
the U.S. Department of Agricul-
ture launched the first areawide
foray against the corn rootworm
in six states this summer.

Pumpkins, corn, and
sunflowers share something in
common at a 120-acre site near
Ames, Iowa. They are being
hand-pollinated to maintain the
genetic variability of a treasure
trove of seeds and plants
gathered from around the world.

Two new bell peppers
developed at ARS' Charleston,
South Carolina, lab are
undaunted by the southern root-
knot nematode, a formidable
pepper pest held in check only
by methyl bromide-until now.

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