Toward a Greener
For centuries, the success of agricul-
ture has been measured by the number of
bushels harvested per acre. But it's be-
coming increasingly clear that food pro-
ducers inthe future will have to do more
than put up big yield numbers to meet the
nutritional needs of the world's popula-
Chronic malnutrition, even in coun-
tries where people get enough calories, is
forcing researchers to take a closer look
at the micronutrient content of the foods
produced by agricultural systems.
While some developing nations still
fail to meet the basic caloric needs of
their people, it is even more alarming
that new research shows many develop-
ing-and even developed-countries
are producing agronomically successful
crops that fail to provide adequate nutri-
ents to meet essential health and nutri-
tional needs. Estimates are that 40
percent of the world's people do not re-
ceive adequate and balanced nutrients to
meet their basic dietary requirements.
Some 840 million people have insuf-
ficient intakes of protein and calories.
And more than 2 billion consume diets
that are less diverse than they were 30
years ago-the result of overdependence
on a shrinking number of high-yielding
staples. The result: A growing number of
people are consuming diets with inade-
quate levels of micronutrients such as
vitamin A, iodine, iron, selenium, and
At greatest risk are the world's poor-
especially women, infants, and children.
They become caught up in a vicious cy-
cle of malnutrition, poor health, and pov-
erty-without much hope for a better
standard of living. In the United States,
feeding programs such as USDA's Spe-
cial Supplemental Nutrition Program for
Women, Infants, and Children (WIC)
help alleviate the problem. But the dis-
advantaged in developing nations often
do not have access to such assistance.
The consequences of micronutrient
malnutrition, or "hidden hunger," are
enormous in terms of a nation's health-
care costs, lost productivity, and slug-
gish development. For example, defi-
ciencies of iron, iodine, and zinc lead to
increased mortality and morbidity rates,
decreased cognitive abilities in children
born to deficient mothers, reduced fam-
ily livelihood, and immense suffering
among those afflicted.
Even in North America, compro-
mised health related to improper diet
occurs. For example, it is common to
find obesity and iron deficiency anemia
among premenopausal women, as well
as low birth weights, diabetes, and zinc
deficiency among children in certain
According to a 1996 report published
by USDA's Economics Research Serv-
ice, of the 10 leading causes of death in
the United States, 4 are related to im-
proper diet: coronary heart disease, can-
cer, stroke, and diabetes. These diseases
account for over half of the deaths in the
United States each year. Possibly 20 per-
cent of them could be prevented by prop-
er diets. These diet-related chronic
diseases cost the U.S. economy an esti-
mated $250 billion annually in medical
treatment and lost worker productivity.
We must find sustainable ways to
produce accessible food supplies of ade-
quate quantity and nutritional quality
that promote health.
The Agricultural Research Service is
an ideal agency for human nutrition re-
search because of its dual mission to
solve basic problems in both agricultural
production and human nutrition. Among
the agency's many laboratories, the U.S.
Plant, Soil, and Nutrition Laboratory at
Ithaca, New York, is one of the few lab-
oratories in the world looking at this
problem from a holistic vantage point.
The laboratory's mission is to im-
prove human and animal health through
research on nutrient movement through-
out the soil-plant-animal food chain. Its
findings are used to improve the nutri-
tional quality and safety of plant-based
This holistic approach emphasizing
the functional relationship between all
aspects of food production, acquisition,
and use offers new hope for providing
sustainable solutions to food system fail-
ures. But holistic solutions cannot pro-
vide short-term fixes. They are by nature
long term-requiring long-term com-
mitment by government and institutions
We must begin now if we are to alle-
viate the misery and correct the conse-
quence of the world's failing food
systems. With 2 billion people suffering
from poor nutrition around the globe,
nations must produce not only more
food, but more nutritious food.
This will require a change in how we
think about agriculture. A holistic ap-
proach to food production could hasten
Third World development by improving
human health and well-being, helping to
bring about a "greener" revolution.
Ross M. Welch
U.S. Plant, Soil, and Nutrition Laboratory
Ithaca, New York
Agricultural Research/May 1999
Vol. 47, No 5
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Making Harvests More Nutritious 4
Moderate Grazing Promotes Plant Diversity 7
Attracting & Tracking an Intractable Pest 8
Prospecting for Health Protectants in Soy 10
Days of Wine ... and Pickles 11
New Accuracy in Sex Selection 12
Baking Sure New Wheats Measure Up 14
Allergic to Rubber? 18
Lactic Acid From Alfalfa 20
Smut--Not Always a Bad Word in Sugarcane Country 21
Fats Ratio Crucial to Lowering Cholesterol 22
Women's Depression Not Linked to Low Iron 22
Science Update 23
Cover: A significant source of quality nutrition, beans-and other staples, like wheat,
corn, and rice-are being improved by plant breeders intent on increasing the
vitamins and trace elements they contain. Photo by Scott Bauer. (K8438-1)
In the next issue!
FRIENDLY FARMING: A 5-year, multimillion-dollar project is look-
ing at environmentally sound practices for the Mississippi Delta that
can also help improve the region's water quality.
SAFER SALADS: Under a new Produce and Imported Foods Safety
Initiative, scientists seek to minimize microbial contamination of fresh
produce as it moves from farm to table.
A GRAPE IS A GRAPE-but it takes DNA fingerprinting to distin-
guish among 14,000 different ones known by more than 50,000
Agricultural Research/May 1999
ARS plant physiologist Ross M.
Welch wants to change the way we mod-
Rather than only increasing yields or
improving disease- and insect-resistance
in plants, Welch wants to harness the
immense power of plant breeding to
solve one of the world's biggest malnu-
trition problems: the shortage of trace
elements and vitamins in the diets of bil-
lions of people.
"Thanks in large part to the legendary
Green Revolution, many more people
around the world get enough calories
from food for their basic sustenance-
except in times of famine," says Welch.
"The Green Revolution increased
overall production of the high-yielding
rice, wheat, and maize that provide large
quantities of most macronutrients, nota-
bly carbohydrates and proteins.
"Unfortunately," he says, "the huge
boost in food production was followed
by a global increase in micronutrient
malnutrition. These high-yielding foods
do not provide enough of the micronutri-
ents-iron, zinc, iodine, essential trace
elements, and vitamins-that are just as
critical to health, though needed in much
During his career as a federal scien-
tist, Welch has worked to transform pro-
duction agriculture to a system that
meets people's micronutrient needs. He
and a small group of scientists at the U.S.
Plant, Soil, and Nutrition Laboratory at
Cornell University in Ithaca, New York,
want to bring the tools and knowledge
base of plant breeding to bear on the
problem of micronutrient malnutrition.
Welch and several colleagues, includ-
ing Robin D. Graham at the University of
Adelaide, South Australia, and Howrath
Bouis of the International Food Policy
Research Institute in Washington, D.C.,
are spearheading an international effort
to identify varieties of rice, wheat, corn,
beans, and cassava that are high in mi-
This research is a collaborative effort
with scientists at several Consultative
Group on International Agricultural Re-
search (CGIAR) centers, including the
International Center for Tropical Agri-
culture (CIAT) in Colombia, the Interna-
tional Maize and Wheat Improvement
Center (CIMMYT) in Mexico, and the
International Rice Research Center
(IRRI) in the Philippines.
Their goal: breed plants that more ef-
ficiently take up trace metals from the
soil and transport more of the micronu-
trients to edible plant parts, especially
the seeds. They also want to propagate
plants that synthesize more phytonutri-
ents-that is, plant-based nutrients and
Technician Larry Heller, of Cornell
University, examines barley plants treated
with plant growth hormones. Scientists
want to know if such treatments affect the
amount of iron in the grain.
beneficial substances such as beta caro-
tene-in their edible parts.
"It's important for plants to accumu-
late these micronutrients in forms that
are biologically available to the human
digestive tract for uptake and use," says
Plants possess genes that regulate
how much of these metals is taken up
from the soil by roots and deposited at
other locations within the plant. These
genes first regulate mechanisms that
make metals in soil more soluble in soil
water. Next, they generate transport
molecules that move metals into root
cells, from which they enter the plant's
vascular system for further transport to
other parts of the plant.
"Breeders can selectively produce
plant varieties in which these traits are
especially prominent," Welch says.
Beans, Beans, a Marvelous
Iron deficiency is the most prevalent
micronutrient problem in the world, af-
fecting over 2 billion people globally,
many of whom depend on beans as their
Welch is working with a laboratory
colleague, ARS animal physiologist
William A. House, Cornell University
research associate Zhiqiang Cheng, and
CIAT scientist Steven E. Beebe in Cali,
Colombia. The team selected 24 breed-
ing lines, or genotypes, of common bean
seeds from the CIAT bean seed bank.
These beans came from diverse genetic
backgrounds but shared a common
trait-an enhanced ability to accumulate
iron and zinc.
The micronutrient-dense CIAT beans
selected were grown in a greenhouse in
Ithaca in nutrient solution labeled with a
Agricultural Research/May 1999
radioactive iron isotope, 59Fe. At matu-
rity, radiolabeled bean seeds were har-
vested, cooked, and freeze-dried. The
dried beans were ground up and fed to
marginally iron-deficient young rats for
"These beans had been genetically
selected for their different iron, zinc, sul-
fur, tannin, and phytic acid concentra-
tions," says Welch. "Both phytic acid
and tannins are known antinutrients that
interfere with iron bioavailability in hu-
mans. The beans' iron levels ranged
from 51 to 157 micrograms per gram of
dry weight. Their zinc levels ranged
from 30 to 65 micrograms per gram."
Seed color, Welch says, is somewhat
correlated to seed tannin levels. White-
seeded beans contain low levels of tan-
nin. "To assure variability of seed tannin
concentration, we included two white
beans in the study," he says.
"Sulfur concentration is an indicator
of sulfur-containing amino acids in
seeds," Welch adds. "These sulfur-con-
taining amino acids may make it easier
for humans to take up and use micro-
nutrients like iron and zinc in foods made
"Our research showed that by select-
ing beans with high iron concentrations,
we also produced beans with greater
quantities of bioavailable iron. The en-
hanced level of iron was readily taken up
and used by the rats' bodies," Welch
"Depending on the genotype, isotope-
labeled beans contained a wide range of
bioavailable iron, phytic acid, and tannin
concentrations. However, when we fed
the cooked bean meal to rats, we found
no relationship between iron, phytate,
KEITH WELLER (K8402-201
With ICP emission spectrometry, ARS plant physiologist Ross Welch can determine the
amount of iron and zinc in this liquid obtained by acid-digesting bean seeds. ICP uses the
unique characteristic light emitted from an element when heated to 8,000oC in an argon
plasma to indicate the element's quantity.
and tannin concentrations and the
amount of bioavailable iron."
According to House, the bioavailable
iron varied from 53 to 76 percent of the
total iron found in the bean seed.
The international team next plans rat-
feeding studies to screen more iron- and
zinc-enriched genotypes selected from
1,440 accessions in the Cali bean collec-
tion for their iron and zinc bioavailabil-
ity. "This core collection represents the
full range of potential genetic variability
among bean species for any given trait,"
In the future, other rat studies are
planned with scientists at other CGIAR
centers, including CIMMYT and IRRI.
These will determine the iron and zinc
bioavailability in select micronutrient-
enriched lines of rice, wheat, corn, and
"Our results indicate that plant breed-
ing can be used to enhance micronutrient
concentrations in staple plant foods,"
Breeding staple plant foods for higher
iron, zinc, and provitamin A carotenoid
concentrations could contribute signifi-
cantly to improving the micronutrient
status of people depending on these
foods as major components of their diet.
What Fertilizing Can Also Do
Besides changing the expression of
genes in the plants themselves, Welch
says farming systems and agronomic
practices can be modified to improve the
healthfulness of food supplies.
"The nutritional quality of food crops
can be greatly affected by the types of
fertilizer used and their placement with-
in the soil," he says. "Adequate fertiliza-
Agricultural Research/May 1999
tion can significantly increase levels of
vitamins in plant tissue. Well-nourished
plants produce more vitamins than those
But while certain micronutrient fertil-
izers and fertilizer practices are well
suited to increasing the density of micro-
nutrients in plant foods, others are not.
For example, using zinc fertilizers can
increase the zinc content of food crops
like beans and wheat-improving them
as a micronutrient source. However,
"For this to happen, the zinc in the fertil-
izer must be available to the roots for
absorption while the plant is making
seeds," Welch says.
Several years ago, he led a research
team in a field study on zinc uptake.
Their study included peas, snap beans,
cabbage, and table beets. They applied
zinc sulfate and phosphorus in narrow
strips at varying rates-from 0 to 80 ki-
lograms per hectare.
The response, they found, depended
on the levels of phosphorus and zinc
used. Zinc uptake improved with in-
creasing supply when phosphorus was
applied at rates needed for optimum
"On the other hand, the study showed
that applying phosphorous without zinc
decreases zinc concentration in seed," he
says. "Only when adequate levels of
phosphorus and more than adequate lev-
els of zinc are applied, do seed concentra-
tions of zinc begin to rise."
Placement of fertilizer in the soil is
also important. Welch cites research
showing that zinc fertilization 2 feet be-
low the soil surface or foliar applications
during reproductive growth are much
more effective than surface applications
at changing the zinc concentrations of
He says that during grain develop-
ment, the amount of subsoil zinc avail-
able is more important than zinc on the
soil surface. During plant development,
many surface soils become dry, while
subsoils remain moist longer, enhancing
"Zinc fertilizer is fairly immobile in
soils," he says. "Thus, root activity is
greater in the moist subsoil during seed
KEITH WELLER (K8400-15)
Growing rice plants in a hydroponic solution containing radioactively tagged iron and zinc
will enable Cornell research associate Zhiqiang Cheng to see how much iron and zinc in the
harvested rice is nutritionally available.
Cornell plant scientist Matthew Wheal
runs a high-performance liquid
chromatograph that quantifies molecules
implicated in iron and zinc uptake by
filling, while roots in the drier surface
soil become less active in acquiring zinc
during this phase of plant development."
Welch says that "to meet the enor-
mous challenges imposed by increasing
global population pressures, a new
greener revolution must build on historic
gains. It must emphasize the rediversifi-
cation of farming systems that include
micronutrient-rich crops-like beans,
peas, lentils, fruits, and vegetables-as
well as cereals. It must address the in-
creasing need for all staple foods without
sacrificing essential micronutrients in
the bargain."-By Hank Becker, ARS.
This research is part of Human Nutri-
tion Requirements, Food Composition,
and Intake, an ARS National Program
described at http://www.nps.ars.usda.
Ross M. Welch is at the USDA-ARS
U.S. Plant, Soil, and Nutrition Research
Laboratory, Tower Road, Ithaca, NY
14853; phone (607) 255-5434, fax (607)
255-1132, e-mail rmwl@ cornell.edu. *
Agricultural Research/May 1999
Colorado study shows the best compromise
between beef production and mix of grassland
DOUG WILSON (K1223-19)
S scientists researching the inter-
dependence of plants and ani-
mals have found that a
moderate level of cattle graz-
ing makes for a more diverse
ecosystem-at least on the
"It evens out the production of indi-
vidual plant species, preventing any one
from dominating," says Richard H.
Hart. He is a rangeland scientist with
USDA's Agricultural Research Serv-
ice. His conclusions come from a graz-
ing study at the Central Plains
Experimental Range (CPER) near
The range is managed by the ARS
Rangeland Resources Research Unit,
which is headquartered at the High
Plains Grassland Research Station near
The High Plains station recently cel-
ebrated its 70th anniversary. The CPER
was established in 1937 on plowed or
overgrazed lands abandoned by farmers
and ranchers during the Dust Bowl
years. So it's no surprise that the cattle-
grazing experiment may well be the
longest running rangeland grazing ex-
periment in the world. Yearling heifers
have grazed the range here for 5 to 6
months each year since 1939, continuing
the work of previous cattle-and the buf-
falo before them.
In a study comparing rangeland
grazed by low to high numbers of cattle,
researchers have found that plant biodi-
versity-as well as ranch profitability-
is highest on land grazed moderately.
"Moderate" is defined as one yearling
heifer for every 16 acres for 5 to 6 months
Plant biodiversity is highest when
high numbers of plant species are com-
bined with a more even distribution of
production among species. Hart and his
colleagues found 46 species of plants on
the moderately grazed land, compared to
43 under heavy grazing and 36 under
While totally ungrazed land had the
same number of plant species as the mod-
erately grazed land, its biodiversity was
undercut by the dominance of prickly-
pear cactus. Prickly pear contributed
nearly half of the total standing crop veg-
etation. Moderately grazed land retained
the same number of species, while reduc-
ing the prevalence of prickly pear to
about 20 percent. It also reduced the
dominance of blue grama and buffa-
lograss, native prairie grasses that are
encouraged by heavy grazing.
All in all, moderate grazing offers the
best compromise when balancing num-
bers of species and their dominance with
beef and forage production.
Hart says cattle weight gains decrease
significantly when the land is grazed
heavily, because there are not only more
mouths to feed, but less forage to graze.
The greater number of cattle does give
the rancher more beef per acre, but the
higher costs of maintaining more cattle
cancels out this advantage.-By Don
This research is part of Grazinglands
Management, an ARS National Program
described on the World Wide Web at
Richard H. Hart is in the USDA-ARS
Rangeland Resources Research Unit,
8408 Hildreth Rd., Cheyenne, WY
82009-8899; phone (307) 772-2433, fax
(307) 637-6124, e-mail
Agricultural Research/May 1999
Entomologist Mohammed A. Latheef tests the response of adult
corn earworm moths to various mixtures of feeding stimulant and
E ntomologist Peter D. Lingren (now retired) had a sim-
ple plan for keeping farmers' most damaging pest-
the corn earworm-out of their corn and cottonfields.
He would find out what adult corn earworm moths
like to eat, attract them with it, and kill them with a
In the South, corn earworm moths, Helicoverpa zea, feast on
corn before they move on to damage cotton. Each year, these
pests cost farmers about $2 billion in losses and control costs.
Lingren's push against the corn earworm began in 1987.
That's when researchers in the ARS Areawide Pest Manage-
ment Research Unit at College Station, Texas, began gathering
information about the insects' taste in food and their capacity
for flight. [See "Migratory Pests: Hit 'Em With All We've
Got," Agricultural Research, December 1994, pp. 4-8.]
A Fatal Attraction
ARS entomologist Juan Lopez, Jr., and agricultural engineer
Kenneth R. Beerwinkle are ushering Lingren's dream into its
commercial development phase. They have applied for a patent
on an attractant that can be used with a feeding stimulant and
insecticide to lure both male and female moths of several insect
species to their last meal.
"Female moths are the prime target because of their egg-
laying and reproductive role," says Lopez. "But this attractant
isn't based on a sex pheromone. Moths of both sexes are lured
to an artificial aroma of night-blooming Gaura plants."
Once attracted, the moths begin feeding. The stimulant helps
them pig-out on the toxic dish so that only a light serving-.01
percent, or 100 parts per million-of carbaryl, a commonly
used household insecticide, is needed to kill them.
The attractant is the culmination of years of research data
gathered by Lopez, Beerwinkle, and retired ARS chemist Ted
N. Shaver. They investigated not only the moths' favorite
foods, but also the chemical aromas, or volatiles, given off by
flowers and their effect on feeding behavior.
Identifying these aromas was tedious. Beerwinkle and Shav-
er collected them in a jar from plant blooms. They looked for
volatiles that were common to different plants. Searching for
just the right scent, they placed hundreds of moths inside a
Plexiglas chamber sectioned into tunnels. Each tunnel con-
tained a cotton roll saturated with a different scent. An attrac-
Agricultural Research/May 1999
Mexican tree-tailed bat dines on a moth in midnight.
tant was deemed a success if the moths followed the scent re-
leased by a cotton roll.
In a 1997 field study, Lopez gave corn earworm moths a
lethal dish that killed 730 moths in a 54-foot cornrow. But not
all of the insects that died from the toxic food were found intact.
"On the morning after treatment, we found wings without
bodies, which we estimated to represent another 150 moths.
Those insects were likely eaten by predators," says Lopez.
"The second night after treatment, we found more dead moths."
Lopez and other ARS researchers at Charleston, South
Carolina, and Ames, Iowa, have tested the attractant on melon-
worms, pickleworms, cabbage and soybean loopers, and on
European corn borers that alone cause losses of $350 million
The pickleworm damages pickling cucumbers. This crop
often requires between six and eight applications of insecticide
at costs ranging from $5 to $15 per acre, according to a North
Carolina State extension specialist.
The Texas researchers are establishing a cooperative re-
search and development agreement with an industry partner to
help commercialize this type of feeding attractant for a wide
range of agricultural insect pests.
Going a Little Batty
While some Helicoverpa moths feed on cotton after leaving
southern corn, others travel north to ravage midwestern corn
crops. In early June, billions of corn earworm moths emerge
from the Lower Rio Grande Valley along the border of Texas
and Mexico. These moths are known to fly as high as 10,000
feet and are often carried more than 250 miles per night by wind
currents, according to ARS meteorologist John K. Westbrook,
who is also in College Station.
To gobble up these airborne moths, researchers are looking
"The voracious appetite of Mexican free-tailed bats may be
a valuable resource for farmers to help reduce populations of
Helicoverpa moths," says Westbrook.
Corn earworm moths are one of the bats' favorite foods. A
million bats can eat nearly 10 tons of insects in just one night,
according to bat specialist Gary F. McCracken of the Univer-
sity of Tennessee. So the 20 million Mexican free-tailed bats
living in Bracken Cave near San Antonio, Texas, could signif-
icantly reduce populations of corn earworm moths.
"About 30 minutes before sunset, you can hear adult bats
leaving the cave on a mission to feed and bring back food to
their young," says McCracken.
While weather specialists use the National Weather Ser-
vice's Doppler radar system (NEXRAD) to detect precipita-
tion, Westbrook uses it primarily to detect moth migration.
In a collaborative study with McCracken and Merlin Tuttle
of Bat Conservation International, Westbrook used the system
to detect the foraging flights of bats traveling toward concen-
trations of migrating Helicoverpa moths.
Westbrook attached radiomicrophones provided by Mc-
Cracken to helium-filled balloons called tetroons. They lis-
tened to the audio signals transmitted while the tetroons drifted
at an altitude of about 2,500 feet. The radiomicrophones picked
up the high-frequency sounds of bats preying on moths. Mc-
Cracken analyzed the content of bat feces, or guano, to confirm
the consumption of corn earworm moths and other insects.
"With insect-detection radar, we could follow moths only to
a range of a few miles," says Westbrook. "But the wide view of
the NEXRAD Doppler radar system allows us to detect masses
SCOTT BAUER (K8404-11
Electrical engineer Paul Schleider (left) and meteorologist John
Westbrook examine clear-air imagery from a NEXRAD Doppler
weather radar. It shows large populations of corn earworm moths
migrating northward from irrigated cornfields in northeastern
Mexico and southern Texas.
Agricultural Research/May 1999
Prospecting for Health
Protectants in Soy
of moths over 60 miles away from a radar site, one of which is
located in Brownsville, Texas. By tracking the insects, we can
determine where they go when they leave Texas cornfields."
He envisions having a system by 2002 that could hand off data
to other radar units, so that changes in insect populations could
be measured within a pest management area with a diameter of
200 to 400 miles. This information could be used by individual
corn farmers or a consortium of pest managers involved in area-
wide pest management.
Like firefighters putting out the "hot spots," the NEXRAD
radar research may be used to develop time-critical maps to help
control infestations over a large area. Pest advisories could alert
growers in agricultural production areas downwind of infested
"One of the strengths of this system is its ability to survey
insects over brushland, dryland, and irrigated cropland," says
James R. Coppedge, who leads the Areawide Pest Management
Research Unit. This unit has one of the most active radar-ento-
mology research programs in the world.-By Linda McGraw,
The research described in this article is part of Integrated
Crop Production and Protection Systems, an ARS National Pro-
gram described on the World Wide Web at http://www.nps.
ars. usda.gov/p rograms/cppvs. htm.
Juan Lopez, Jr., Kenneth R. Beerwinkle, John K. Westbrook,
and James R. Coppedge are in the USDA-ARS Areawide Pest
Management Research Unit, 2771 F&B Rd., College Station, TX
77845; phone (409) 260-9351, fax (409) 260-9386, e-mail
k-beerwinkle @ tamu. edu
A corn earworm moth sips nectar from a night-blooming Gaura plant.
The soybean, long known in the Orient as a "yellow
jewel," has been processed in the United States for vegeta-
ble oil and protein since the mid-1920s. Now it's clear this
plant gem may hold even more valuable health treasures.
Agricultural Research Service scientists and their Uni-
versity of Illinois colleagues are prospecting for compo-
nents that might help cancer-free animals and humans stay
"While some natural and synthetic chemicals disrupt
DNA and sometimes result in malignancies, other com-
pounds in our food supply help protect against irreversible
DNA damage," says Mark A. Berhow. He is an ARS
chemist at the National Center for Agricultural Utilization
Research in Peoria, Illinois.
The idea is to provide DNA-friendly dietary com-
pounds-termed chemoprotectants-to counter unfriendly
ones in food or the environment.
In search of the extra treasure, the scientists are examin-
ing some leftovers from soybean oil and protein extraction.
The leftovers make up a gooey molasses called phyto-
chemical concentrate (PCC). Until now, PCC has been pro-
cessed into a light-brown powder for livestock feed. But
compounds isolated from the leftovers may become more
valuable than the main processed soy products.
Someday, soybeans may be bred or genetically trans-
formed to contain greater amounts of chemoprotectants.
The current search for these substances, supported in part
by the United Soybean Board, may serve as a model for
research on other foods.
Geneticist Michael Plewa of the University of Illinois at
Urbana-Champaign and his colleagues expose cell cultures
of Chinese hamster lungs and ovaries to PCC components
prepared by Berhow and ARS plant physiologist Steven F.
Vaughn. Plewa's team then challenges these cells with a
chemical known to induce tumors. PCC and some of its
components prevent DNA damage.
The university researchers assess DNA breakage in the
cells. Once the scientists associate a particular PCC portion
with minimal cell breakage, they further purify it for exper-
iments designed to precisely identify the protective compo-
In preliminary studies, mice fed certain PCC compo-
nents for 2 weeks were protected from cell damage.-By
Ben Hardin, ARS.
MarkA. Berhow and Steven F. Vaughn are in the USDA-
ARS Bioactive Agents Research Unit, National Center for
Agricultural Utilization Research, 1815 N. University St.,
Peoria, IL 61604; phone (309) 681-6595, fax (309) 681-
6693, e-mail firstname.lastname@example.org
Agricultural Research/May 1999
Days of Wine ... and Pickles
Y ou wouldn't nor-
mally think of
wine and pickles
but an enterpris-
ing ARS researcher has
found a way to improve qual-
ity analysis of both products.
Using high-performance ..
liquid chromatography ,
(HPLC) is nothing new. It's
been around for 30 years. But
for food scientists studying
cal magic that turns cukes
into pickles and grapes into
wine-HPLC is both a help-
ful tool and a hassle.
The HPLC needs as little
as a hundredth of a drop for
analysis. But with fermented
vegetables and wines, there are so many
components that the instrument can't
separate them all. This has meant that
scientists studying these products have
had to prepare and inject multiple sam-
"In pickle fermentation, there are two
sugars present, as well as multiple acids
and alcohols," says chemist Roger F.
McFeeters, who is in the ARS Food Sci-
ence Research Unit at Raleigh, North
Carolina. "Wine chemists have it
worse-there are even more compo-
But McFeeters changed this well-
known scientific instrument so the meas-
urements could be done in 20
minutes-without multiple runs. That
cuts running time in half. Better still, sci-
entists don't have to lose several hours
reconfiguring the HPLC to run the sepa-
rate tests for sugars and acids.
McFeeters devised his time-saving
method against the advice of the HPLC
manufacturer who said that it wouldn't
work. He added one detector that finds
acids by how they conduct electricity
and another that measures alcohols and
sugars by electrochemical detection. In
this way, he was able to concurrently an-
A Further Step Towa
alyze for both a sugar and an acid that the
HPLC column couldn't separate.
He found the same technique could
also be modified slightly to detect and
measure sulfites in wine. Added to
crushed grapes, sulfites ensure a quality
wine by killing wild yeasts that can pro-
duce poor flavor. Unfortunately, re-
search 20 years ago showed that even
at low concentrations, sulfites can
trigger a potentially fatal allergic-
like reaction in people with asthma.
With the new HPLC technique
McFeeters developed, sulfites
can be detected at levels as low as
3 parts per million. That's the
equivalent of a drop of water in a
"Keep in mind, I found that
most U.S. wines contain almost
no sulfites," says McFeeters. "To
test the HPLC, I had to spike Amer-
McFeeters ran the spiked wine
and saw sulfites on the printout. To
confirm, he treated the samples with a
sulfite-destroying chemical and reran
the test. The printouts showed no sulfite
bump, confirming the technique's accu-
racy. That got McFeeters thinking.
"It seems possible that
packers could use sulfites to
preserve pickles in storage-
then remove the sulfites with
a food-safe chemical like
peroxide when the pickles
are ready to be packed and
sold," says McFeeters. "It's
an idea that flows from the
wine, right back to pickles,
my main research."-By Jill
This research is part of
'rd Crop Production, Product
Value, and Safety, an ARS
National Program described
on the World Wide Web at
Roger F. McFeeters is in
the USDA-ARS Food Science
Research Unit, Box 7624, Raleigh, NC
27695-7624; phone (919) 515-2979, fax
(919) 856-4361, e-mail
Agricultural Research/May 1999
New Accuracy in Sex Selection
F or more than a decade, it has
been our goal to provide live-
stock producers the opportunity
to predetermine the sex of off-
spring to increase reproductive
efficiency, says ARS animal physiolo-
gist Lawrence A. Johnson.
Now, what may have once appeared
impossible to accomplish is possible.
In 1989, Johnson, head of the Germ-
plasm and Gamete Physiology Labora-
tory in Beltsville, Maryland, first
developed a method to separate living
and male-producing (Y-chromosome)
sperm based on their DNA content.
USDA has patented this method, called
the Beltsville Sperm Sexing Technolo-
gy, and licensed it to several firms for
commercial development for livestock
reproduction and in human medicine.
Initially, Johnson proved the method
worked with rabbits, pigs, and cattle, but
he could only sort 1.5 million to 2 mil-
lion sperm per day with 75- to 90-per-
cent accuracy. [See "Good Breeding:
From Simple Beginnings to Genetic En-
gineering," Agricultural Research, No-
vember 1991, pp. 4-9.] The technology
has come a long way since that initial
The principles on which the method
is based are still the same, but Johnson
and his colleagues have transformed the
technology in a major way. They have
proved its effectiveness in sheep, labo-
ratory animals, and other species. Re-
cently, scientists with Colorado State
University and XY, Inc., of Fort Collins
reported the birth of a filly from sexed
So how does one separate something
that the naked eye can't see?
Johnson uses a fluorescent dye that
sticks to the DNA. The dye binds to the
sperm based on how much DNA the X
and Y chromosomes in the sperm are
carrying. Female-producing X sperm
contain 2.8 to 7.5 percent more DNA
than male-producing Y sperm, depend-
ing on the species.
Sperm cells are analyzed and sorted
using a flow cytometer/cell sorter. When
a laser beam illuminates the dye, each
10 4g ,
Heifer calf born to a cow inseminated with sorted X-chromosome-bearing sperm.
sperm gives off light proportional to its
DNA content and is separated into dif-
ferent tubes, depending on the amount
of light emitted. The X sperm always
glows brighter because of the greater
amount of DNA.
"Cell sorters are built and sold pri-
marily for the medical community and
are used in cancer and other types of
medical research," Johnson says. "Since
blood cells are spherical, we had to adapt
the cell sorter for domestic animal
sperm, which generally have paddle-
shaped heads and long tails. Then we did
what had never been done before on a
consistent basis: separated living sperm
for use in producing offspring."
Johnson and colleagues Glenn R.
Welch and Wilem Rens have made
three significant enhancements to the
Beltsville technology that dramatically
increase the practicality and chances
that the animal industry will adopt the
"First," Johnson says, "we improved
our sperm-processing procedures, re-
ducing the sperm's exposure to excess
dye. Second, we developed a new nozzle
[patent pending] for the flow cytometer
cell sorter that allows 70 percent of the
sperm-compared to only 30 percent
with the older version-to be properly
aligned to the laser beam and sorted into
the correct tube. Third, we modified a
newly developed commercial high-
speed cell sorter and adapted it not only
for sorting sperm, but to fit our new noz-
The combination of these improve-
ments has led to a 15- to 20-fold increase
in production rates of sorted sperm pop-
ulations. Now, 35 to 40 million of both X
and Y sperm can be sorted in an average
8-hour day, compared to 1 to 2 million
Johnson notes that accuracy depends
on the DNA difference between the X
and Y sperm, which varies with the spe-
cies being sorted. This difference allows
sorting to take place and determines the
accuracy of a positive selection,
Agricultural Research/May 1999
displays a pig born as
a result of studies
using sorted sperm
and in vitro
Biologist Glenn Welch operates the
Beltsville high-speed sorter that separates X
and Y sperm. Livestock inseminated with
the sexed sperm will produce offspring of
the selected sex with 90-percent accuracy.
For example, boars carry about 3.6
percent more DNA in their X sperm than
in their Y sperm; bulls, 3.8 percent
more; and humans, 2.8 percent. The
wider the difference, the easier it is to
sort with greater accuracy.
Sperm-sorting technology can now
be used with both conventional and
deep-uterine artificial insemination in
With conventional artificial insemi-
nation, sperm are placed just inside the
cow's uterus-a procedure that requires
about 5 million sexed sperm and an hour
of sorting time. With deep-uterine in-
semination, only about 300,000 sperm
need to be placed to get pregnancy.
Because pigs require much larger
doses of semen for artificial insemina-
tion, the scientists must use in vitro fer-
tilization with sexed sperm. The embryo
is implanted in a surrogate sow.
In a recent experiment showing the
effectiveness of the sperm-sexing tech-
nology, eight litters of pigs were born at
Beltsville using sorted X-chromosome
sperm. Ninety-eight percent of the
pigs-or 43 of 44-in the 8 litters were
female. Three control litters produced at
the same time with unsexed sperm re-
sulted in equal numbers of male and fe-
To date, more than 500 animals have
been born using sexed semen, and all
have been healthy and normal. Johnson
says the technology could potentially
save the cattle industry millions of dol-
"Sexing sperm could help farmers
get the required numbers of the desired
sex without producing the other sex,"
says Johnson. "This speeds the rate at
which they can achieve genetic improve-
ment while reducing production costs."
Johnson says the clearest example of
this is with dairy cows. "Normally a
farmer would use the top 40 percent of
his herd to reproduce enough female re-
placement calves. With sexed semen, a
farmer would only need to use the top 20
Another benefit of sex-sorting sperm
is efficiency in conserving genetic re-
sources. Johnson says that when storing
rare germplasm for use by later genera-
tions, conservators can maintain only the
sperm needed to produce sexed offspring
desired for particular situations, like se-
lecting a cow versus a bull, for example.
"Sex preselection provides an oppor-
tunity to improve management flexibili-
ty using this technology," he says.
Johnson is collaborating with several
scientists around the world to help estab-
lish the technology for use in livestock
and to perfect it for commercial use.-
By Tara Weaver, ARS.
This research is part ofAnimal Germ-
plasm, Resources, Conservation, and
Development, an ARS National Program
described on the World Wide Web at
Lawrence A. Johnson, USDA-ARS
Germplasm and Gamete Physiology
Laboratory, Bldg. 200, Rm. 124, 10300
Baltimore Ave., Beltsville, MD 20705-
2350; phone (301) 504-8545, fax (301)
Agricultural Research/May 1999
Baking Sure New Wheats Measure Up
SCOTT BAUER (K7219-2)
millers, and bakers have
special problems in meet-
ing the challenges associ-
ated with delivering our
daily bread to our dinner tables.
Millers and processors demand vari-
eties developed for specific end uses.
Information needed for every stage of
production is available from four ARS
wheat quality laboratories located in
Manhattan, Kansas; Wooster, Ohio;
Fargo, North Dakota; and Pullman,
Washington. These laboratories were
established to help breeders improve the
quality of wheat varieties grown in their
respective regions. The labs were
charged with determining what factors
are important to wheat quality and devel-
oping reliable tests for measuring these
Before a new wheat seed is ever made
available to growers, the researchers at
these quality labs have thoroughly ana-
lyzed the milling and baking quality of
thousands of experimental breeding
lines from federal, state, and private
For Bread and Buns-Hard Winter
Each year, at the Hard Winter Wheat
Quality Laboratory in Manhattan, Kan-
sas, researchers evaluate about 5,000
hard winter wheat samples from 3 feder-
al regional breeding nurseries and 18
state and private breeders. Hard winter
wheat is used to make white pan bread
and hot dog and hamburger buns.
To obtain accurate information, the
Manhattan researchers have adapted
two powerful analytical tools: near-in-
frared reflectance and single-kernel
The data on protein, moisture, and ash
from these predictive measurements and
from biochemical analyses help ARS
food technologist Bradford W. Sea-
bourn and chemist Okkyung Kim Chung
develop end-use quality prediction
equations. The analyses show the rela-
tive quantity and composition of pro-
teins, lipids, enzymes, and starches in
many wheat lines so that scientists can
see how these differ and how the differ-
ences between varieties are related to the
differences in end-use quality.
In 1998, Seabourn, Chung, and South
Dakota State University researchers de-
veloped a relational database now avail-
able to breeders through the World Wide
Web. Instead of poring through a thick
publication, breeders can opt for a user-
friendly computer file to zero-in on a
wheat line's major deficiencies and rank
each line based on its milling and baking
Because protein plays a major role in
the quality of bread each wheat variety
produces, ARS chemist George L.
Lookhart has adapted capillary electro-
phoresis to quickly identify protein pat-
terns as genetic fingerprints. These can
be used to distinguish between varieties
and to predict end-use quality.
Lookhart also developed a fast meth-
od for measuring the amount of insoluble
polymeric protein. The more there is in a
wheat, the better the dough-mixing prop-
erties of its flour.
One important accomplishment has
been the adaptation of methods using
small quantities of flour for a mixograph
analysis of dough strength. These meth-
ods, which have reduced the flour needed
Agricultural Research/May 1999
from 35 grams to 5, permit earlier evalu-
ation of potential varieties.
"Occasionally, breeders can't supply
enough flour from their experimental
wheat lines to perform adequate baking
tests. To overcome this problem, we
designed thimble-sized baking pans that
hold tiny loaves made from only 2 grams
of flour," says ARS baker Margo S.
Caley in Manhattan.
"Our location in the Great Plains is
important to our customers-the grow-
ers and breeders of hard winter wheat,"
says Chung, who leads the Grain Quality
and Structure Research Unit and directs
the Hard Winter Wheat Quality Labora-
tory at Manhattan.
"We know firsthand the environmen-
tal factors influencing this class of
wheat. The same varieties grown in dif-
ferent environments may vary greatly.
About 60 percent of the variations in
wheat quality are caused by environmen-
For Cakes and Cookies-Soft Red Win-
Future generations will likely benefit
from wheat flour improvements made
today by researchers at the Soft Wheat
Quality Laboratory in Wooster, Ohio.
"We're working on the wheat flour
that will be used in your wedding cakes,"
says ARS food technologist Charles S.
Gaines to young people touring the lab-
He says that because it takes 8 to 14
years to breed a new commercial wheat
variety, and it' 11 be about that long before
these students will begin to marry. Since
1992, Wooster scientists have been coor-
dinating a worldwide consortium for
mapping the genome of soft red winter
wheat varieties, which are used to make
cookies, cakes, pastries, and crackers.
ARS food scientist Patrick L. Finney
says that today's mapping technology is
allowing wheat scientists at the Wooster
lab to tie all their knowledge about the
functional properties of soft red winter
wheat to individual genes.
"We're focused on the practical
side-milling and baking-but we're
still dealing in genetic engineering,
physics, chemistry, biology, and food
technology," says Finney, who directs
the Wooster lab.
The number of new wheat variety re-
leases has risen sharply since the 1930s,
or even the 1970s. For the past decade,
Wooster researchers have evaluated
more than 8,000 wheat samples a year
submitted by about 20 public and a dozen
private breeding organizations.
Researchers are devising tests for
more realistic assessments of wheat
condition than the current method of
weighing test batches. Gaines found a
way recently to separate shriveled ker-
nels from rain-puffed ones. Both lower a
grain's test weight and market value. But
unlike shriveled kernels, rain-puffed
ones have all the flour that millers expect
and are softer than nonpuffed kernels.
When breeders are really serious
about a variety and close to releasing it,
scientists do the final quality test: They
use the flour to bake cookies. The larger
and softer the cookie, the better the
For Asian Noodles and Flatbreads-
Soft White Western Wheat
The ARS Western Wheat Quality
Laboratory in Pullman, Washington,
helps bring tasty Asian and Middle East-
ern dishes to the table. Flatbreads, noo-
dles, and Japanese sponge cakes, as well
as some traditional American cookies
and cakes, are made with soft white
wheat grown in the Pacific Northwest.
"Farmers in this region grow all mar-
ket classes of wheat except soft red win-
ter," says ARS cereal chemist Craig F.
Morris, director of the Pullman lab. But
soft white wheat is predominant. Most of
it is exported to Pakistan and Pacific Rim
countries to make dozens of types of flat-
breads and noodles.
Each year, the lab evaluates up to
7,000 genetically unique samples rang-
ing from a few tablespoons to 2 bushels
each. As at the other wheat quality labs,
Pullman researchers tell how each line or
variety performs in milling and baking
trials so breeders can make the best
"Out of 2,000 samples, only 1 or 2
may eventually become commercial va-
rieties," says Morris.
The Pullman lab is also leading one of
the biggest research efforts in North
America on waxy wheat through a coop-
erative research and development agree-
ment with a major food company. Waxy
wheat contains a natural mutation that
prevents the kernels from making a
starch called amylose that is present in
Agricultural Research/May 1999
"Starch from waxy wheat absorbs
much more water than normal wheat
starch, stays gooey after heating and
cooling, and doesn't lose water when
frozen and thawed," says Morris.
What are these traits good for?
"That's what we hope to find out," he
says. "It's almost like going to the Am-
azon jungle and bringing back a new
plant species. We've never had this kind
of wheat before."
ARS provides the wheat and quality
testing, while company researchers look
for ways to use the wheat. Japanese udon
noodles already use wheat with a related
mutation, called partially waxy.
For Pizza, Pasta-Hard Red Spring
and Durum Wheat Classes
At the ARS Wheat Quality Laborato-
ry at Fargo, North Dakota, researchers
evaluate up to 2,000 hard red spring
wheat breeding lines for milling and
Food technologist Gary Hareland and
physical science technician Dehdra Puhr
evaluate the quality of test bread loaves
made with a blend of durum and spring
baking quality and up to 1,000 durum
wheat breeding lines for milling and pas-
ta quality. Durum wheat is used primari-
ly for pasta and noodles. Hard red spring
wheat is noted for its high gluten content,
which accounts for good loaf volume.
Food technologist Gary A. Hareland,
director of the Fargo lab, explains, "Glu-
ten imparts flexibility and strength to
dough as it rises and helps maintain
structure during baking."
About half of the hard red spring
wheat grown in the United States is ex-
ported. Much of the rest is blended with
winter wheat flour to improve the quality
of white pan bread. The flour is also used
in non-pan breads such as bagels, pizza
crust, and hard rolls.
Durum wheat breeding lines used to
make pasta are also rated for firmness
and weight of cooked spaghetti. The sci-
entists are studying ways to measure
spaghetti stickiness, which is unaccept-
able to consumers.
Durum prices vary more from year to
year than prices of other wheats. "To
help even out the price swings," says
Hareland, "we're trying to find another
niche for durum besides pasta."
Traditionally, 65 percent of a durum
kernel is milled into semolina, a granular
material that is mixed with water and
SCOTT BAUER K8423-11
The quality of pasta made from semolina-
the purified middlings of milled durum
wheat-is an important consideration in
breeding new varieties. To evaluate the
semolina, physical science technician
Jadene Wear extrudes spaghetti, which will
be dried and test-cooked.
In response to demands from wheat growers and processors for improved
varietiess suitable for their geographic regions. the U.S. Congress established
four ARS \heat quality laboratories.
1936-To correct poor milling and baking qualities of commercial soft red
winter wheat varieties, the Soft Wheat Quality Laboratory was established at
1937-To answer the requests of Great Plains wheat growers seeking im-
provements in hard winter wheats, the Hard Winter Wheat Quality Laboratory
was established in Manhattan, Kansas. Whereas there were only three varieties
in the 1930s, today there are hundreds. This lab helped standardize quality
analysis for these wheats.
1946-To analyze and evaluate the quality of wheat (mostly soft white)
grown in the Pacific Northwest, the Western Wheat Quality Laboratory was
established in Pullman, Washington.
1963-To put researchers closer to growers of hard red spring and durum
wheat classes, the Hard Red Spring and Durum Wheat Quality Laboratory was
relocated from Washington, D.C., to Fargo, North Dakota.
Agricultural Research/May 1999
extruded into pasta. Another 10 to 12
percent of the kernel is milled into flour
for noodles or, if the quality is low, into
livestock feed. Durum's use in noodles
may decline with the advent of new
white winter and spring wheats.
Coming to the rescue are durum
breeding lines for dual-purpose bread
and pasta wheat. The feat involves trans-
ferring certain glutenin protein genes
from bread wheat to durum wheat.
But even conventional durum flour
could find its way into more bread.
Hareland and colleagues have dis-
covered a way to make a good loaf with
up to 60 percent durum. Durum flour
makes a more flavorful bread with a
slightly nutty taste. Until now, baking
qualities of such breads have been poor
unless the flour mix included no more
than 25 percent durum.-By Linda
McGraw, Don Comis, Kathryn Barry
Stelljes, and Ben Hardin, ARS.
Food technologists Charles Gaines (left) and Ron Martin watch as a stream of air in the
large tube separates light, shriveled kernels of soft red winter wheat from fully filled out,
higher density kernels. The amount of flour produced from the heavier kernels will
represent the full genetic flour yield potential of the wheat.
This research is part of New Uses,
Quality, and Marketability of Plant
Products, an ARS National Program de-
scribed on the World Wide Web at http:
//www. nps. ars. usda. gov/programs/
Okkyung Kim Chung is at the USDA-
ARS Grain Marketing Research and
Production Center, 1515 College Ave.,
Manhattan, KS 66502; phone (785) 776-
2703, fax (785) 776-2792, e-mail
okchung @ usgmrl.ksu. edu.
Patrick L. Finney is in the USDA-ARS
Soft Wheat Quality Research Unit, 1680
Madison Ave., Wooster, OH 44691;
phone (330) 263-3890, fax (330) 263-
pfinney postboxx. acs. ohio-state. edu.
Craig F. Morris is at the USDA-ARS
Western Wheat Quality Laboratory, Rm.
209, Johnson Hall, Pullman, WA 99164-
6420; phone (509) 335-4062, fax (509)
GaryA. Hareland is at the USDA-ARS
Wheat Quality Laboratory, Harris Hall,
P.O. Box 5677, Fargo, ND 58105-5677;
phone (701) 239-1340, fax (701) 239-
hareland@ badlands.nodak.edu. +
Agricultural Research/May 1999
To better understand milling
performance, ARS food technologist Gary
Hareland (right) and North Dakota State
University food technician Merle
Skunberg evaluate the quality of semolina
from a cultivar of durum that was milled
in the pilot mill.
"An estimated 20 million Americans," says plant physiolo-
gist Katrina Cornish, "are allergic to the latex in gloves, cathe-
ters, condoms, or other products made from the most widely
used source, the Brazilian rubber tree."
Cornish, with ARS at Albany, and agency colleagues in
Phoenix, Arizona, explore new ways to make production of
guayule latex practical, efficient, and profitable. The ARS ex-
periments-some in cooperation with universities in Califor-
nia, Arizona, New Mexico, Texas, and Utah-address
conventional breeding and genetic engineering of the plant, as
well as its planting, cultivation, and harvesting. Other studies
investigate techniques for extracting, storing, and processing
Composed of rubber particles in a water-based suspension,
latex is a higher value product than solid rubber. This fact, plus
the urgent need for hypoallergenic alternatives to conventional
latex, has made guayule's latex-as opposed to its solid rub-
ber-the focus of the ARS re-
search. JACK DYKINGA (K8360-1)
Until this decade, most stud-
ies of guayule, Parthenium ar-
gentatum, dealt primarily with
its rubber, which hasn't been
produced commercially in this
country since 1929.
Today's guayule plants are
superior to those of the past,
thanks to plant breeding by ARS ,
and university scientists in Ari-
zona. In 1997, these researchers. 4 ,
offered growers seed from gua- .i;
yule plants selected for fast ..
growth and high latex content. lti
Plant physiologist Katrina Cor
ARS geneticists Terry A. Mau examine guayule plantlet,
Coffelt and David A. Dierig, engineered.
who are at the U.S. Water Con-
servation Laboratory in Phoe-
nix, are continuing the quest for
even better guayule. They are
screening thousands of candidate plants in greenhouses and
outdoor plots. Their experiments also help breeders pinpoint
whether environment or genetics is the dominant factor affect-
ing growth rates and latex yields.
In her laboratory, plant physiologist Katrina Cornish checks
seedlings produced for use in experiments to improve guayule
plants. The prototype, allergen-free latex products shown were
made from guayule. Photo by Jack Dykinga. (K8358-1)
Biotech experiments by Cornish focus on genetically engi-
neering guayule plants to boost their latex levels. "Guayule
lines that we've tested," says Cornish, "contain up to 10 percent
latex. Even a small increase in that latex level could mean a
significant increase in potential profits for growers and proces-
Cornish, along with Christopher J.D. Mau and Mary H.
Chapman at the Western Regional Research Center in Albany,
and former Albany researcher Javier Castill6n, developed a
faster, easier way to move new genes into guayule tissue in the
Their procedure, patterned after one used by scientists else-
where with other plant species, relies on bathing pieces of
leaves in a solution containing a reworked form of a microbe,
Agrobacterium tumefaciens. The modified bacterium has the
experimental genes inside and can slip them into guayule cells.
The leaf pieces are nurtured to form shoots and, later, roots.
The team is apparently the
first to use this approach suc-
cessfully with guayule.
Says Mau, "With this tech-
nique, we get more genetically
engineered guayule plants than
with an earlier, more cumber-
some procedure. That other ap-
proach required piercing plants
with a very thin needle to make
an entryway for the microbe."
Castill6n and Cornish also
produced a new, simplified pro-
identical copies-or clones-of
promising plants, using shoots
h and associate Christopher promising plants, using shoots
at they have genetically snipped from the parent plant.
They cultivate shoots in small
containers filled with a nutrient-
rich liquid and plugs-small,
stubby rolls of a papery material
that look something like minia-
ture, tightly compressed rolls of paper towels. Later, they move
the developing plantlet, with new roots anchoring it to the plug,
directly into greenhouse pots.
This procedure, not yet reported by any other guayule re-
searchers, causes little if any damage to guayule's young, frag-
ile roots. An earlier technique was riskier: A plantlet had to be
pried from a test tube and nutrient gel pulled from its roots
before it could be transplanted to pots.
Plantlets raised with the Albany technique form roots as
readily as those grown with the earlier procedure. And they
adjust to the greenhouse in a few days instead of several weeks.
Used successfully at Albany for more than 3 years, the new
Agricultural Research/May 1999
Lactic Acid From Alfalfa
procedure has been adopted by a lab in South Africa. It is ex-
pected to be in use in a guayule display planned for next year at
Disney's Epcot Center in Florida.
Estimating What You've Got
ARS scientists Francis S. Nakayama and Stephen H. Vin-
yard in Phoenix collaborated with Cornish, Chapman, and stat-
istician Linda C. Whitehand at Albany to develop a simple,
reliable procedure for estimating latex levels in guayule sam-
The basic approach requires cutting branches into half-inch-
long pieces, grinding them for precise periods in a blender, and
filtering the resulting liquid, or homogenate. The liquid is spun
in a device called a microcentrifuge to separate the creamy latex
from the rest of the slurry. Then the latex is coagulated, dried,
"We estimate," says Nakayama, "that we're extracting at
least 90 percent of the latex in each specimen without having to
use harsh solvents."
The researchers anticipate that it won't be practical for latex
producers to always process guayule shrubs immediately after
harvest. Earlier studies already showed that guayule rubber
levels decrease in storage, but the Albany and Phoenix scien-
tists were the first to track changes in latex levels from both
stored shrubs and stored homogenate.
Medium-size branches-those about one-fourth- to one-
half-inch in diameter-consistently had more extractable latex
than smaller or larger branches tested throughout a 5-week pe-
riod. Stored branches retained all of their latex for 2 weeks. But
homogenates didn't begin to lose latex until the beginning of the
fifth week, "meaning that homogenate is the best option for
processors who need to store the harvest for more than 2
weeks," says Cornish.
"Up until that time," says Nakayama, "it is probably cheaper
to store the crop as whole shrubs, provided they are not allowed
to dry out. Further studies will give us more details about the
cost advantages of the two storage options."-By Marcia
This research is part ofNew Uses, Quality, and Marketabil-
ity of Plant Products, an ARS National Program described on
the World Wide Web at http://www.nps.ars.usda.gov/pro-
Katrina Cornish is in the USDA-ARS Process Biotechnology
Research Unit, Western Regional Research Center, 800 Bucha-
nan St., Albany, CA 94710; phone (510) 559-5950, fax (510)
559-5777, e-mail email@example.com.
Francis S. Nakayama is in the USDA-ARS Environmental
and Pant Dynamics Research Unit, U.S. Water Conservation
Laboratory, 4331 E. Broadway Rd., Phoenix, AZ 85040; phone
(602) 379-4356, ext. 255, fax (602) 379-4355, e-mail
Lactic acid-a colorless or slightly yellow, syrupy liquid-
is naturally formed by the fermentation of lactose, or milk sug-
ar. Its name comes from the Latin word "lac," which means
milk. Commercially, lactic acid can be made synthetically from
chemicals or organically as a byproduct of corn fermentation.
Last year, ARS agricultural engineer Richard G. Koegel in
Madison, Wisconsin, and University of Wisconsin researchers
were the first scientists to make lactic acid from alfalfa. This
accomplishment will give alfalfa an extra economic boost.
The USDA-Wisconsin research partnership has already pro-
duced several alfalfa-derived products, such as carotenoids and
protein concentrates, worth from $1,000 to $2,000 per acre
Lactic acid is commonly used as a food additive for flavor
and preservation, but a new market for organic lactic acid exists
for making biodegradable plastics. The current lactic acid mar-
ket in the United States is about 50,000 tons per year, more than
half of which is imported.
The alfalfa fibrous fraction, from which lactic acid is made,
results when juice is expressed from freshly cut herbage to
make other high-value products, including food- and feed-
grade proteins and carotenoids.
ARS research with transgenic alfalfa also produced industri-
ally valuable enzymes.
Instead of using chemical treatments, Koegel pretreated al-
falfa fiber for 2 minutes in hot water at 430oF and 350 pounds-
per-square-inch pressure. With hot-water pretreatment,
hydrolytic enzymes, and a Lactobacillus bacterium, the re-
searchers got lactic acid yields as high as 60 percent.
"Many microorganisms can ferment either five- or six-car-
bon sugars. The Lactobacillus bacterium that we used is an
exception because it can ferment both," Koegel says.
Koegel is now attempting to boost lactic acid yields using the
microbe without pretreatment. If this work proves successful, it
may help lower industry's cost of production.
Growing alfalfa in some agricultural areas is preferred over
corn and soybeans, which require more fertilizer and soil tillage
that can lead to soil erosion. Another benefit: Alternating alfalfa
with corn and soybeans reduces pesticide use and increases
yield of corn and beans.-By Linda McGraw, ARS.
Richard G. Koegel is at the USDA-ARS U.S. Dairy Forage
Research Center, 1925 Linden Drive West, Madison, WI
53706; phone (608) 264-5149, fax (608) 264-5275, e-mail
Agricultural Research/May 1999
Not Always a Bad Word in Sugarcane Country
D during a time when most concerned citizens want to
wipe out smut, Rex W. Millhollon is trying to encour-
His campaign isn't over freedom of speech. In-
stead, the respected agronomist is studying new ways
to fight a noxious southern weed with a lethal dose of smut-
loose kernel smut, that is.
Sphacelotheca holci, as it's called scientifically, is a natural
fungus that attacks johnsongrass, a perennial weed that
plagues many crops.
In Louisiana's bayou country, where Millhollon conducts
his research, sugarcane growers rely on herbicides to rid their
fields of the pesky grass. But this raises concerns over the
potential buildup of chemical residues in the environment.
Cost is another concern, says Millhollon, who is in the Agri-
cultural Research Service's Sugarcane Research Unit at Hou-
Cane growers spend up to $50 per acre applying herbicides,
an expense they anticipate recovering through increased sugar
yields. But each season, they must renew the fight, drawing on
the chemicals once again.
Now, Millhollon is exploring smut's biological control
potential to break that cycle.
One of the weed's few known pathogens with mycoherbi-
cide potential, the S. holci fungus infects the seedhead, turning
its reproductive structure into a crumbly, black mass. Yet, its
ability to attack only johnsongrass and related sorghum spe-
cies keeps this smut from exacting a similar toll on other grass
crops like sugarcane and wheat, which succumb to other spe-
cies of smut. Most sorghum cultivars were found resistant to
loose kernel smut ofjohnsongrass, but a few can become in-
"It's an obligate parasite that can only complete its life
cycle on the host plant," says Millhollon.
"In nature, when wind-blown spores come in contact with
the johnsongrass host and germinate, the hyphae enter the
plant, colonize growth tissue in the tips of buds, stems, or
rhizomes, and complete the fungus' life cycle by producing
spores in the reproductive tissue of newly formed seedheads,"
"If you can get it to infect the whole plant, the fungus will
stunt its growth, reducing competitiveness with sugarcane and
cutting down on the production of seed that, if dispersed, can
remain viable in soils for many, many years."
In greenhouse experiments with johnsongrass, Millhollon
injected a spore solution of smut directly into the weed's tis-
sues. The result: smutted seedheads and plant infection rates
of 75 to 85 percent.
But injection isn't practical under field conditions. So Mill-
hollon used lab culture techniques to grow billions of sporidia,
an infectious form of the fungus. This enabled him to formu-
late a mycoherbicide spray.
Outdoors, Millhollon observed plant infection rates of 50 to
80 percent 40 to 60 days after applying the spray. Though prom-
ising, the treatment didn't protect the cane crop as well as con-
"If we inject the spores into the plant, the whole plant be-
comes infected," Millhollon explains. "But when we spray it in
the field, we get only partial infection. So weed growth isn't
greatly affected, and we still get a lot of weed seed production."
Greater virulence-or disease-causing ability-he says,
may help to overcome the problem. One approach is to breed the
fungus with other races of smut that exchange their genes sex-
ually. The trick: ensuring the new breed won't pose a new threat
to cereal crops like sorghum.
A more "surgical" approach might be to use biotechnology
techniques to increase virulence by manipulating specific fun-
gal genes. In either case, says Millhollon, giving smut a helping
hand could "take it to the next level and add one more element
to johnsongrass control."-By Jan Suszkiw, ARS.
This research is part of Integrated Insect, Mite, and Weed
Control," an ARS National Program described on the World
Wide Web at:
Rex W. Millhollon is in the USDA-ARS Sugarcane Research
Unit, P.O. Box 470, Houma, LA 70361; phone (504) 853-3174,
fax (504) 868-8369, e-mail firstname.lastname@example.org. *
RAPRV FIT7FlAI fl lunl-lam
Johnsongrass, Sorghum halepense, a perennial weed through much
of the South, may be facing a new biological control.
Agricultural Research/May 1999
Fats Ratio Crucial to
If you go on a low-fat diet, you will surely lower your cho-
lesterol count, right?
Not necessarily, reports chemist Gary J. Nelson with the
ARS Western Human Nutrition Research Center.
Among 11 healthy men aged 20 to 35 who volunteered for
a study led by Nelson, cholesterol levels didn't change signif-
icantly-regardless of whether the
men were on a low-fat or high-fat
Stint. Fat calories made up 39 percent
of the day's total calories in the high-
f fat menus, while accounting for only
2 percent during the low-fat regi-
r men-meaning that fat calories were
nearly cut in half for those days.
Why didn't such a drastic drop in
fat intake lead to a similar decrease in
"Perhaps because we didn't change
the ratio of fats; that is, saturated to
polyunsaturated to monounsaturat-
ed," says Nelson. "We stayed with 28
percent saturated fat-the kind in but-
ter or lard; 33 percent monounsaturat-
ed; 6 percent monounsaturated
transfats, as are found in some marga-
rine; and 29 percent polyunsaturated
fats-the kind in healthful cooking
oils. Other minor fatty acids made up
the remaining 4 percent.
"These findings," Nelson says, "should be of interest both
to people who are trying to lower their cholesterol and to health
care providers advising patients on how to change their diets to
improve their cardiovascular health."
For the experiment, all volunteers ate the high-fat diet for 20
days. Then, six volunteers ate low-fat meals for 50 days, while
the other five volunteers ate the high-fat foods-whole milk
instead of nonfat and cream cheese, notjelly, on their breakfast
bagels, for example. After that, the two groups crossed over to
the opposite menus for the final 50 days of the study.
Nelson collaborated in the study with ARS chemists Perla
C. Schmidt and Darshan S. Kelley at the Nutrition Center.-By
Marcia Wood, ARS.
Gary J. Nelson is at the
USDA-ARS Western Human
Nutrition Research Center,
University of California, One
Shields Ave., Davis, CA
95616; phone (530) 752-
5356, fax (530) 752-8966, e-
Women's Depression Not Linked
to Low Iron
Women experience more depression during their childbear-
ing years. And twice as many women as men are clinically
depressed, according to standardized tests. This gender differ-
ence begins in adolescence and is more pronounced among
married women aged 25 to 45 with children.
Researchers at ARS' Grand Forks Human Nutrition Re-
search Center in North Dakota wanted to know if this phenom-
enon is related to marginal iron levels.
About 1 in 5 women of childbearing age has low iron stores,
compared to 1 in 60 men, says Janet R. Hunt, a nutritionist and
dietitian. So she and psychologist James G. Penland tested the
iron status and psychological state of 384 women aged 20 to 45
"Other studies on the question have tended to go both
ways," Hunt says. "But there has never been a strong case for
a relationship. Our study indicates no relationship between
marginal iron status and depression."
The survey volunteers filled out a standard psychological
profile and mood checklist and also gave a blood sample. Hunt
says the study used the most sensitive tests of iron stores and
standardized psychological profiles, unlike some earlier tests.
The researchers found no relationships between mood
scores and three signs of iron status in the blood-serum fer-
ritin, serum iron, and hemoglobin. But the study did yield some
surprises, says Hunt.
Women with low ferritin levels were less likely to describe
themselves as depressed or tired than women with normal fer-
ritin. The researchers believe the finding may be unique to this
group of women and not representative of the population in
A severe iron deficiency, however, could cause fatigue and
depression, Hunt says. Anemia would show up in a simple
hemoglobin or hematocrit test. "So women experiencing these
symptoms would not need to have their ferritin levels tested as
has been suggested in the lay press," says Hunt.
More surprises: Iron stores were not associated with meat
consumption or the use of iron supplements. But iron stores
were higher in women who used oral contraceptives and lower
in women who regularly donate blood.-By Judy McBride,
Janet R. Hunt is at the USDA-ARS Grand Forks Human
Nutrition Research Center, P.O. Box 9034, University Station,
Grand Forks, ND 58202-9034; phone (701) 795-8328, fax
(701) 795-8395, email@example.com. *
Agricultural Research/May 1999
Science Project Ideas for
Elementary to high school students in
a hurry can visit a new web site for a list
of 140 publications full of ideas for sci-
ence projects-most related to the agri-
cultural sciences. The site, "Projects and
Experiments for Young Scientists," was
set up by the Technology Transfer Infor-
mation Center of ARS' National Agri-
cultural Library. It's the latest effort by
ARS to interest young people in science.
The publications list hundreds of project
ideas on subjects ranging from Christ-
mas tree farming to Samoan fruits and
vegetables. Many of the publications
should be available at local public and
school libraries. The site's address is
Also for kids is a web site produced by
ARS' Information Staff, "Science for
Kids." It has stories about ARS research
geared to students ages 8 to 13 and can be
found at http://www.ars.usda.gov/is/
kids. Kate Hayes, USDA-ARS National
Agricultural Library, Beltsville, Mary-
land; phone (301) 504-6875, e-mail
khayes @ nal. usda. gov.
News on Cancer Link to
Excess Beta Carotene
Why did high doses of beta carotene
supplements apparently increase lung
cancer rates in smokers in two large in-
tervention trials a few years ago? A study
of ferrets may have found an answer.
These animals absorb and metabolize
beta carotene much as humans do. In the
study, excess beta carotene stored in the
ferrets' lungs became oxidized into
byproducts that decreased a tumor sup-
pressor and increased a tumor promoter.
ARS and the National Institutes of
Health (NIH) funded the research.
The findings emphasize the advan-
tage of getting important nutrients
through foods, rather than supplements.
Several studies have suggested that
people who eat abundant fruits and veg-
tables rich in beta carotene and other
carotenoids have a lower incidence of
cancer, particularly lung cancer. Body
cells convert some beta carotene into a
vitamin A-like compound, retinoic acid,
that may dampen cell division. It is being
used to treat skin cancer and leukemia.
But the new study suggests that an excess
of beta carotene-if exposed to high
oxygen levels in lung cells and oxidizing
effects of cigarette smoke-could thwart
its protective potential.
In tests, some ferrets received beta
carotene in amounts proportional to the
30 milligrams per day given in large hu-
man trials by NIH and researchers in Fin-
land. For 6 months, one group of ferrets
received both the supplements and expo-
sure to cigarette smoke that was equiva-
lent to a person smoking 1-1/2 packs a
day. Two other groups got just the sup-
plements or the smoke; a control group
got neither. Gene products that promote
cell division were highest in the group
that got both treatments-three to four
times higher than in the control group.
Robert Russell and Xiang-Dong Wang,
Jean Mayer USDA Human Nutrition Re-
search Center on Aging at Tufts, Boston,
Massachusetts; phone Russell at (617)
556-3335, Wang at (617) 556-3130, e-
mail russell @ hnrc.tufts.edu.
More Clues on Horse
New findings may lead to help for a
disease that destroys brain cells in hors-
es. Equine leukoencephalomalacia, or
ELEM, is a rare disease caused by a toxin
that frequently contaminates corn, but at
concentrations of less than 1 or 2 parts
per million. In 1995, ELEM killed 38
horses in Kentucky and Virginia.
The toxin in corn, fumonisin, is made
by the fungi Fusarium moniliforme and
F. proliferatum. Dietary concentrations
in excess of 15 ppm can make a horse
sick, and the damage is irreversible. The
toxin interrupts the way in which a
horse's liver, kidney, and possibly other
tissues make fats known as sphingolip-
ids. It also causes sphinganine-an inter-
mediate fat molecule-to accumulate,
while depleting supplies of other neces-
According to a study by ARS and
University of Georgia scientists, there is
another fungal compound that can tem-
porarily reduce sphinganine accumula-
tion in mice. Several species of fungi
make this compound, known variously
as ISP-I, myriocin, or thermozymocidin.
If the finding is confirmed, it may lead to
treatments for sick horses, as well as to
ways to prevent the toxin from harming
them. ARS and Emory University scien-
tists have received a patent on a tech-
nique to detect fumonisin poisoning in
an animal's tissue, blood, and urine
based on changes in sphinganine. The
Food and Drug Administration is consid-
ering recommendations to protect both
humans and livestock from fumonisin.
Ronald T. Riley, USDA-ARS Richard B.
Russell Agricultural Research Center,
Athens, Georgia; phone (706) 546-
3377, e-mail firstname.lastname@example.org.
Correction: This photo should hate
appeared on page 15 of the April 1999
issue with the following caption:
rescue in a test
plot at the ARS
tion and Soils
tonr in Kimherl..
Agricultural Research/May 1999
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On the World Wide Web
what we eat in
Learn what-and how much-as well as how we fare nutritionally. Check out
the ARS Food Surveys Research Group's web site at http://