qu ,. Ch
[tr. *-m e
Down the Yellowstone, the Milk, the
White and Cheyenne;
The Cannonball, the Musselshell, the
James and the Sioux;
Down the Judith, the Grand, the Os-
age, and the Platte,
The Skunk, the Salt, the Black, and
The Allegheny, the Monongahela,
Kanawha, and Muskingum;
Down the Miami, the Wabash, the
Licking, and the Green,
Teaming Up for
Better Water Quality
How is USDA's water quality pro-
gram like the Mississippi River?
It, too, involves many rivers-not
quite all the rivers carried by the
Mississippi to the Gulf, but some major
tributaries like the Platte, the Des
Moines, the Red, and the Missouri.
And the program includes almost all
the states bordering the river, from its
start as a meandering creek in northern
Minnesota to its end at the Gulf of
Mexico-2,500 miles later.
Begun in 1990, the Management Sys-
tems Evaluation Areas (MSEA) was an
unprecedented water quality effort led by
two USDA agencies-the Agricultural
Research Service and the Cooperative
State Research Service (now the Coop-
erative State Research, Education, and
Extension Service, CSREES)-and uni-
Until 1996, MSEA was a Midwest
program. But then it was partnered with
CSREES' Agricultural Systems for En-
vironmental Quality. This broadened
MSEA's scope, bringing in Ohio's Lake
Erie Basin, the Mississippi Delta region,
and the eastern Coastal Plain.
Both the delta and Coastal Plain ar-
eas are experiencing problems with al-
gal blooms. In the Gulf, a growing
hypoxic--oxygen-starved-dead zone is
killing shellfish. Along the eastern
Coastal Plain, problems with fish-killing
The Cumberland, the Kentucky, and
Down the Ouachita, the Wichita, the
Red, and Yazoo-
Down the Missouri, three thousand
miles from the Rockies;
Down the Ohio, a thousand miles from
Down the Arkansas, fifteen hundred
miles from the Great Divide;
Down the Red, a thousand miles from
Pfiesteria and red tide have been
Nitrogen and phosphorus are possible
causes of these blooms. Nitrate-nitrogen
is a byproduct of nitrogen fertilizer used
on nearly all cropland, as well as on
lawns and other areas. Phosphorus and
nitrogen reaching waterways also come
from nonfertilizer sources, such as waste
Reducing nitrogen loadings into the
Mississippi by 20 percent could increase
oxygen levels in the Gulf, according to
the National Science and Technology
Council's Integrated Assessment Re-
In many places, our research through
MSEA has shown how farmers can
reduce these loadings to safe levels in
surface water and groundwater. As a
result, MSEA has brought new tech-
nology to the forefront. For example,
portable chlorophyll meters can now de-
tect nitrogen levels in plant leaves. TDR
(time-domain reflectometry) electronic
probes can monitor soil moisture.
MSEA has packaged new and not-so-
new techniques into workable systems,
such as growing corn and soybeans on
raised seedbeds. The ridge tillage system
was tested at all the Midwest MSEA
sites-Iowa, Kansas, Minnesota, Mis-
souri, Nebraska, the Dakotas, Ohio, and
Wisconsin. It reduced herbicide and
In fact, the most pleasant surprise from
the Midwest program has been a virtual
absence of herbicides in groundwater.
Down the great Valley, twenty-five
hundred miles from Minnesota,
Carrying every rivulet and brook,
creek and rill,
Carrying all the rivers that run down
two-thirds of the continent-
The Mississippi runs to the Gulf
-from Virgil Thomson's 1937 score
for Pare Lorentz'New Deal-era film
documentary "The River"
Popular herbicides like atrazine and
alachlor just didn't show up at the levels
We must continue to evaluate the
extent to which the newer pesticides-
along with other compounds, such as
hormones and antibiotics-can be car-
ried away in runoff from farms and
watersheds to pose environmental or
health risks. We must also continue to
study toxic organisms in runoff, such as
Cryptosporidium, which can occur in
human and animal wastes.
The good news has to be balanced
against Missouri's experience with very
high levels of pesticides in farm runoff.
This was caused by local soil conditions,
but those conditions are representative
of 7 million acres of midwestern crop-
land with potential for similar problems.
USDA is determined to give farmers
as many tools as possible to help them
greatly reduce their share of the water
quality problem. A good example is in
Iowa, where farmers voluntarily adopt-
ed practices when they saw they could
get the same or better corn yield with 50
pounds less nitrogen fertilizer per acre.
Its not just in Iowa, however, that
farmers are adopting practices to control
runoff and protect groundwater. The
Midwest program has taught us that if
some adopt new practices, others will
follow-and that's exactly what is hap-
pening in many areas.
ARS National Program Leader for
Water Quality and Management
Vol 48, No I
Agricultural Research is published monthly by
the Agricultural Research Service. U.S Depart-
ment of Agriculture I LSDA i. The Secretary of
Agriculture has determined that this penodical is
necessary in the transdcton of public business
required by laaw.
Dan Glickman. Secreiar
U S Department of Agnculture
I. Mile) Gonzalez. Lnder Secretar)
Research, Education. and Economics
Flu)d P. Horn, Administrator
Agricultural Research Service
SandI MNiller Ha,'. Director
Acung Editor: Robert Sowers
An Director. William Johnson
Photo Editor Anta Daniels
Staff Photographers Scott Bauer
Information in this magazine is public property
and may be repnnied withoutt permission. Non-
copy nghted photos are a ailable to mass media in
color transparencies Order by photo number and
date of magazine isue.
Agncilrrual Research magazine article, and
photographs are posted on the World Wide Web
monthly at http://, aw.ars.usda go%/is/AR/.
Subscripnon requests should be placed ith New
Orders. Supenntendent of Documents. P 0 Box
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Editor..Arnc ilcurl Reiearch'5. 5601 Sunn) side
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armagditasrr arsusda go\.
This magazine maj report research involving pes-
ticides. It does not contain recommendations for
their use, nor does it imply that uses discussed
herein haje been registered All uses of pesticides
must be registered by appropnate .late and/or
federal agencies before they can be recommended
Reference to any commercial product or service
is made % ith the understanding that no dicrimi-
nation is intended and no endorsement b\ LISDA
The Ui S Department of Agriculture prohibits
discrnnination in all its programs and acii ilie>,
on the basis of race. color ridtlonal origin.
gender religion, agc. diabilit). polical beliefs.
sexual orientation. and martial or family status
SNot all prohibited bases apply to all programs i
Persons \a Ih disability, who require allernatme
means tor communication of program informa-
tion iBraille. large print, audiotape. etc. should
contact USDA's TARGET Center at i 2111 720-
2600 s noice and TDDi.
To file a complaint ol[ discrimination. rute:
USDA. Director. Office of Civil Rights, Room
326-W'. While Bldg., 14th & Independence
Avenue, SW, Washington, DC 202 50t -94 I0, or
call I 202 i 720-5964 (Voice and TDDi. USDA is
an equal opportunity pros ider and employer.
Precise Inputs for a Cleaner Environment 4
Corn Seed Pretreatment Reduces Fusarium 8
The Degreening of Canola 9
Inter-Bacterial Communication! 10
Biodegradable Decoy Reduces Insecticide Use 12
Dates Go Under Cover 15
Vitamin K: Another Reason To Eat Your Greens 16
CORN: Taking Genetic Stock 18
Ultra-Narrow-Row Cotton 20
Science Update 23
COVER: Technician Jeff Nichols collects a water sample from the Walnut Creek
watershed in Ames, Iowa. Samples are collected weekly from this area and
surrounding watersheds to study the effects farming practices have on water quality.
Photo by Keith Weller. (K8721-3)
In the next issue!
(I HOLDING BACK FLOODWATERS ARS scientists are using a software
program called SITES to analyze and design new flood-control structures to replace
thousands that are in urgent need of rehabilitation.
(0 WHAT ATTRACTS MOSQUITOES TO US? The answer to this question may
lead to better repellents.
( EAT SOY! Soy is believed to calm signals between cells. This calming effect may
reduce the chance of developing some chronic diseases.
Precise Inputs for a Cleaner Environment
When the sandhill cranes
pass over the Platte River
Valley in Nebraska this
spring on their annual
flight north, they'll fly over a cleaner
A decade has passed since the U.S.
Department of Agriculture began a ma-
jor clean water effort in the Corn Belt
from the Platte River to the Des Moines
River to the Mississippi River to the
In 1990, USDA began five compre-
hensive research and demonstration
projects to evaluate and develop farming
methods that safeguard water resources.
Known as the Management Systems
Evaluation Areas (MSEA), the sites are
in Iowa, Kansas, Minnesota, Missouri,
Nebraska, the Dakotas, Ohio, and
Wisconsin. MSEA, led by USDA's
Agricultural Research Service; Coop-
erative State Research, Education, and
Extension Service; and university
colleagues, involves close cooperation
with federal, state, and local agencies.
MSEA's cornerstone is the close
integration of research and education
activities. This water quality program
merged in 1996 with a broader USDA
program called ASEQ, for Agricultural
Systems for Environmental Quality.
With this merger, the joint program
expanded to Mississippi and North
The work initially emphasized reduc-
ing the amount of pesticides reaching
groundwater, says Dale A. Bucks, ARS
national program leader for water qual-
ity management. But the emphasis soon
expanded to include nitrates in surface
water and groundwater and pesticides in
"Now the program also emphasizes
phosphorus and collects data on air qual-
ity, soil management, off-site impacts,
and newer farm practices," Bucks says.
Pesticide levels in groundwaters were
far less than originally anticipated. Iowa
results were typical: The common herbi-
cide atrazine showed up in well water at
levels above the U.S. Environmental
Protection Agency's standard for drink-
ing water only once in 8 years of inten-
sive sampling. Bucks warns, however,
that more research is needed on newer
pesticides and other synthetic chemicals,
such as hormones and antibiotics, in run-
off from fields, farms, and watersheds.
SCOTT BAUER (K8701-1)
so01 scientist Jim achepers measures
canopy reflectance from several plants
using real-time sensors being developed
for mobile applications. Selected colors
monitored by this inexpensive sensor are
compared with more extensive data
collected by costly spectroradiometers.
Why the emphasis on nutrients?
Because they have generally been a
problem at the study areas, Bucks says.
Annual "dead zones" off the Gulf Coast
and fish kills from Pfiesteria on the East
Coast also pushed nitrogen and phos-
phorus into the limelight. These nutrients
can feed harmful algal blooms asso-
ciated with these problems.
The Midwest part of the joint pro-
gram is still going strong, changing the
landscape of American farming, often
far beyond the Corn Belt.
In Nebraska-Groundwater Quality
James S. Schepers, an ARS soil nitro-
gen expert at Lincoln, Nebraska, says that
groundwater in the Platte River Valley has
less nitrate and pesticides in it today be-
cause of the program. Nitrate-nitrogen
levels in the groundwater have been re-
duced from 30 parts per million (ppm) to
10 to 15 ppm. EPA's standards for drink-
ing water call for a maximum of 10 ppm.
"The techniques that led to these re-
ductions are being adopted across the
country," says Schepers. "Basically, they
center on the burgeoning field of preci-
sion agriculture and split applications of
nitrogen fertilizer." Schepers serves on a
committee promoting solutions like this
Farmers traditionally apply nitrogen
fertilizer in the fall based on the results
of a soil test. They often add "insurance
fertilizer," the rate of which is based on a
guess about how much more fertilizer
might be needed by spring planting time.
Fertilizer has been cheap enough that
farmers would rather overapply it than
risk having an anemic corn crop, says
The Midwest program came up with
an alternative: Apply nitrogen in two or
more applications-beginning with a
starter dose in spring-and monitor for
nitrogen deficiency before applying
The Nebraska scientists developed
several ways to monitor, including the use
of a portable chlorophyll meter to in-
stantly test plants for nitrogen deficiency.
Farmers could combine the meter with a
special soil test at planting time and
another when the corn is 18 inches tall.
Applications Become More Precise
MSEA scientists have documented
that crop yields and nitrogen needs with-
in a field vary tremendously. So one of
their main priorities was to develop
equipment that can apply nitrogen at a
Agricultural Research/January 2000
The Nebraska scientists designed sen-
sors to pinpoint nitrogen needs based on
sunlight reflected from crop leaves.
Mounted on a high-clearance sprayer,
the sensors look like small headlights.
One stares skyward so it can measure
daylight intensity. Another points toward
the plants and measures light reflected
from the crop to detect how much nitro-
gen the plants have in their leaves. Farm-
ers can drive though the cornfield-no
matter how tall the crop is-and auto-
matically add nitrogen where needed.
ARS scientists in Nebraska developed
the sensors through a cooperative re-
search and development agreement with
a private company. Now they are work-
ing on second-generation sensors, says
Schepers. Similar reflectance techniques
are being tested on airplanes and
Variable-rate equipment is key to the
precision agriculture revolution current-
ly brewing in the agricultural equipment
industry, fueled in part by the program
for water and environmental quality.
In precision agriculture, farmers ap-
ply only the type and amount of inputs-
water, pesticides, or fertilizer-that
plants need for optimal yields. To do this,
they rely on sensors that collect data on
plant and soil conditions as the tractor
moves across the field. GPS (Global Po-
sitioning System) receivers locate the
tractor in the field, and computers on-
board the tractor calculate the best pos-
sible yield and the soil's capacity to hold
chemicals. The results of the calculations
are used by the computer to adjust the
application rate of each chemical as the
tractor moves along. The onboard com-
puters can also use data from stored maps
or aerial photographs instead of sensor
But Schepers says the first line of de-
fense against nitrate leaching is wisely
managing irrigation and drainage water.
"It's excess water that carries nitrate to
groundwater," he says.
Excess phosphorus from animal
manure applied as fertilizer can also be
a water quality concern. So ARS soil
scientist Brian J. Wienhold, also at
Lincoln, is testing manure from swine
raised on a new corn variety bio-
engineered to reduce phosphorus ex-
cretion. Wienhold is assessing the
potential this low-phosphorus manure
has for reducing runoff losses of
In Missouri-Soil Type Does
As in Nebraska, scientists working at
the Missouri site rely on sensors to
achieve the best use of fertilizer nitrogen
within each field. "Our tactics are
different, based on different soil con-
ditions," says Eugene Alberts, "but the
goal is the same: to not over- or under-
apply nitrogen fertilizer." Alberts leads
the ARS Cropping Systems and Water
Quality Research Unit in Columbia,
To set variable rates for nitrogen, the
Missouri scientists experimented with
sensors for estimating claypan topsoil
depth. These relied on measuring the
soil's electrical conductivity. The lower
the conductivity, the deeper the topsoil.
As it deepens, crops are higher yielding,
justifying more nitrogen fertilizer.
"There's no sense in fertilizing for a
yield of 200 bushels of corn an acre on
soil that could never yield even 100 bush-
els," says Alberts.
The research focuses on the claypan
soil region in north-central and north-
eastern Missouri. The region is repre-
sentative of more than 7 million acres of
Midwest cropland. Newell R. Kitchen,
an ARS soil nitrogen management expert
who works with Alberts, says, "A clay-
pan layer restricts roots and lowers crop
yields. The claypan also causes surface
runoff that has high herbicide levels in
spring and early summer."
The main study area in Missouri is the
28-square-mile Goodwater Creek water-
shed, with 50- to 90-acre commercial
Agricultural Research/January 2000
JAMES SCHEPERS (K8696-19)
'P, :!. -
"" ": ":'' ;
ir' i'2 'I~"~
Mounted on a high-clearance sprayer, crop canopy sensors monitor plant greenness, which
is translated into a signal by an onboard computer that controls the application rate of
nitrogen fertilizer to the soil.
SCOTT BAUER (K8700-1)
cornfields and 1-acre study plots. One-
fourth of the wells in the watershed ex-
ceed the drinking water standard for ni-
trate. Most drinking water comes from
municipal reservoirs, but people in iso-
lated areas get their drinking water from
Kitchen says, "we need to find a way
to fine-tune farming methods to avoid
loading the groundwater with nitrate.
Ken Sudduth, an ARS agricultural engi-
neer, and I are field-testing several in-
novative strategies for applying nitrogen
at a variable rate.
"Over the last 4 years, the Missouri
program has expanded to include most
of the northern and some of the central
parts of the state."
In Iowa-Less Is Better
In one Iowa watershed, farmers used
MSEA findings to lower nitrogen fertil-
izer use by 50 pounds per acre over 20
percent of the watershed.
ARS scientists in Ames, Iowa, credit
the reduction to split nitrogen appli-
cations and a technique they developed
to reduce nitrate leaching. In the Corn
Belt states-the nation's heaviest users
of nitrogen fertilizer-most nitrogen
fertilizer is injected into the soil as a
pressurized gas called anhydrous
ammonia. Knifelike blades cut a slot in
the soil into which the gas is dispensed
through a hose alongside the blade.
The scientists at the National Soil
Tilth Research Laboratory worked with
Iowa State University colleagues to in-
stall a disk behind each "knife" to mound
soil on both sides of the slit. This pre-
vents the slot from funneling rainwater
that could carry nitrate toward ground-
Jerry L. Hatfield, head of the Soil
Tilth Laboratory in Ames, says he and
his colleagues are starting to test newer
herbicides that are highly selective and
applied at doses a fraction of those of
conventional herbicides. The new her-
bicides also break down in the soil in a
Spectroraaiometers can be used to measure
and record the spectral signature of
reflectance from an individual leaf. Here,
technician Jim Tringe uses the device to
identify special wave bands or colors
unique to a given crop stress, such as
Technician Andrew Pond uses an iron
oxide test strip to measure the amount of
phosphorus present in a runoff sample.
"Part of the natural evolution of this
water and environmental quality pro-
gram is a response to changes in pesti-
cide technology as well as farm
practices," Hatfield says.
The Iowa site has high nitrate levels
in water drained off fields by under-
ground pipes. This water pours directly
into streams. Hatfield says 40 percent
of the Midwest has poorly drained soils
that require similar pipes. The pipes have
perforations so some drained water can
leak back into the soil as it flows the
length of the pipe into a stream.
The researchers are testing various
solutions. One is installing the pipes in
a bed of woodchips and planting deep-
rooting alfalfa over the top. The wood-
chips are a carbon source to feed
microbes that break down the nitrate into
harmless components as it leaches from
the pipes. Any nitrate that manages to
leach below the woodchips will be
caught by the alfalfa roots.
Again in line with program findings,
the Des Moines water treatment plant
reported record levels of nitrate this year
from the Des Moines and Raccoon Riv-
ers, but no problem with herbicides.
Hatfield says the researchers' goal is
to design farming systems that mesh
practices for better use of water with
those for better use of nutrients.
"We've been developing practices
that lower subsurface drainage nitrate
content and improve yields at the same
time," Hatfield says. These concepts are
being applied to the Lake Springfield
watershed in Illinois to help improve
water quality in the lake.
In Ohio-Handling Drainage
Researchers in Ohio are focusing
their efforts on the effects of drainage
on surface water quality. They are
studying poorly drained areas of Ohio
as part of the ASEQ program. The main
concerns are nitrates and pesticides
reaching surface water after leaving
underground drainage pipes.
Agricultural Research/January 2000
Amy Morrow, a chemist in Ames, Iowa, inspects the operation of the soil extraction robot that is used to remove herbicides from soil
samples. This unit has processed soil samples throughout the life of the MSEA program.
They have built a highly successful
system for poorly drained soils. This
system, which uses uniformly spaced
drainage lines, was designed by scientists
at ARS' Soil Drainage Research Labora-
tory in Columbus, Ohio, working with
researchers at Ohio State University.
The system supplies irrigation water
that goes into the drainage pipes during
the summer, says Norman R. Fausey,
who heads the Columbus lab. The plants
get a uniform water supply, thus promot-
ing nutrient use and maximum yields.
Almost no nitrates or pesticides leach
below the pipes, and the amount of ni-
trates and pesticides leaving the field
through the drains in the fall, winter, and
spring is greatly reduced.
Recently, the Ohio researchers began
testing the treating, storing, and reusing
of drainage and surface runoff water to
irrigate. The water is routed to a wetland
constructed for that purpose. The wet-
land removes sediment and nutrients
before the water is stored in a reservoir.
The system has the potential to produce
zero discharge to streams-helping to
improve water quality and reduce peak
In Minnesota-Ridge Tillage
Scientists in Minnesota are looking
at how ridge tillage affects pesticide
leaching. Robert H. Dowdy, of ARS'
Soil and Water Management Research
Unit at St. Paul, Minnesota, says that ro-
tating crops with the ridge tillage sys-
tem caused an 85-percent reduction in
the amount of atrazine herbicide used
over an 8-year period, compared to con-
tinuous corn grown conventionally.
"We reduced atrazine by using it only
every other year when corn was grown
and by applying it in bands over the row.
This allowed us to use two-thirds less
on each application," Dowdy says.
"Ninety-eight percent of the atrazine is
gone by the end of the corn season."
Dowdy's team evaluated the ability of
an ARS-developed Root Zone Water
Quality Model to predict leaching of
herbicides in soil. "We found that it
accurately predicted pesticide levels in
the top 6 inches of soil," Dowdy says.
"It overestimated leaching below that
depth because of flaws in the lab
technique used to provide the model with
leaching information. We have since
developed a new technique that corrects
The Northern Sand Plain scientists
also found a way to irrigate crops more
precisely by a weekly check of soil
moisture with a portable time domain
reflectometry (TDR) unit.
Agricultural Research/January 2000
SCOTT BAUER (K8699-1)
Soil scientist Brian Wienhold and
technician Julie Paschold examine a runoff
sample collected from plots on which
nitrogen and phosphorus losses are studied.
The plots received swine manure differing
in phosphorous content.
"While the MSEA program has used
new technology like the TDR unit and
the chlorophyll meter, many of the
practices in the successful ridge tillage
system are not new. What is new about
this program is that it packages practices
together into systems that work, pro-
tecting water quality and growing crops,"
The same is true for all the sites in the
environmental quality program.-By
Don Comis, ARS.
This research is part of Water Quality
and Management (#201) and Soil Re-
source Management (#202), ARS Nation-
al Programs described on the World
Wide Web at http://www.nps.ars.usda.
Scientists mentioned in this story can
be contacted through Don Comis, 5601
Sunnyside Ave., Beltsville, MD 20705-
5129; phone (301) 504-1625, fax (301)
504-1641, e-mail firstname.lastname@example.org.
Corn Seed Pretreatment Reduces Fusarium
Finding kinder, gentler microbial friends for corn plants has led to a strategy for
controlling a fungal toxin-even before the crop is planted.
The fungus. Fusarium montliforme, is especially dangerous if it gets into corn
fed to horses or swine, says ARS microbiologist Charles W. Bacon. While con-
tamination with the funonisin toxin produced by E nioniliforme is rare in the
United States, the Food and Drug Administration established tolerance-or max-
imum allowable-levels as a precaution in early 1999.
Bacon heads the Toxicology and Mycotoxin Research Unit in Athens, Georgia.
He and fellow microbiologist Dorothy M. Hinton found a safe, convenient way to
prevent corn contamination from the moment the seedlings come up. They began
working on the project in 1996.
Now a company is developing a seed treatment with a harmless natural bacteri-
um that suppresses F moniliforme. Farmers may have access to the treatment in a
year or two, pending final field tests.
Fusarium thrives inside corn plants, dwelling in ,paces between the cells. And
one obstacle to removing it has been that many isolates actually benefit the plants.
"While the fungus is bad news for mammals, we found that most strains of it
seem to help improve corn root growth." says Bacon. "This better enables the
plant to survive dry conditions and related stress. What we've done is substitute a
bacterium that is harmless to both plants and animals."
Last year, Bacon and Hinton found that a strain of Bacillus subtilis fills up
corn's intercellular spaces before F moniliforme gets the opportunity. Scientists
call this competitive exclusion.
And the B. subtilis wants the plant all to itself. In petri dishes, it actually re-
pelled F. moniliforme and may do more for plants' roots than Fusarium does. The
helpful B. subtilis has shown promise not only in the lab but also in greenhouses
and small-scale field plots in Georgia and lowa.
Bacon and Hinton filed a patent on the technology, which caught the eye of
Donald S. Kenney, director of technology for Gustafson LLC, a seed treatment
company in Piano, Texas.
"To control fungal toxins in an ear of corn through a seed treatment is especial-
ly interesting to us." says Kenney. "You're protecting the harvest by doing some-
thing far upstream, before the farmer even buys the seed."
Scientists have found other strains of B. subrilis that prevent corn from being
contaminated with Fusarium. But the growing plants would have to be "vaccinat-
ed" with the microorganism through sprays or other treatments. And that's im-
practical for farmers.
However, seed treatments are very practical. "We use a fermentation process to
stabilize the bacteria and increase concentrations," says Gustafson plant patholo-
gist Philip Brannen. "Seed companies would bu) the product from us in a liquid or
Another benefit is the product's stability. Corn seed sellers get about 10 percent
of their product returned from retailers each year, says Kenney. Pretreated seed
may have to be stored a year before it can be resold. The treatment seems to last at
least 2 years, which is plenty of time for resale.-By Jill Lee, formerly with ARS.
This research is part of Food Safety, an ARS National Program (#108) de-
scribed on the World Wide Web at http://www.nps.ars.usda.gov/programs/
Charles Bacon is in the USDA-ARS Toxicology and lMycotoxin Research Unit.
Richard B. Russell Research Center, 934 College Station Rd., Athens. GA 30605;
phone (706) 546-3158. faxi (706) 546-3116. e-mail email@example.com. *
Agricultural Research/January 2000
The Degreenng of
KEITH WELLER (K8718-2)
I n the world of plants, green is usually good
... except in canola seeds. That's because
too much green means too much chlorophyll
has remained in the seed-meaning the seed
hasn't matured. Freezing temperatures can
prevent maturation, causing the seed to stay green.
An early frost can cost North American canola
growers up to $150 million.
"The freezing interrupts chlorophyll break-
down in canola seeds," explains Agricultural
Research Service plant physiologist C. John
Whitmarsh. "Seeds can reach maturity and have
a high oil content, but if they're green, their priceLar
s, Laser light i
drops." material ext
Seed crushers remove the green from the oil canola seeds
with bleaching clays, which produce an added
expense and pose an environmental problem.
Canola is an oilseed crop grown mainly in parts of western
Canada, with some acreage in Ontario and the Pacific North-
west, north-central, and southeastern United States. Its yellow
flowers produce pea-shaped pods that contain tiny seeds har-
vested for their oil. Canola oil contains omega 3 fatty acids,
acclaimed for improving human immune and vascular systems.
"Ultimately, we may be able to provide industry with genet-
ically altered canola plants tailor-made to tolerate freezing tem-
peratures," says Whitmarsh, who is based at Urbana, Illinois.
"Many plants break down chlorophyll even after a freeze. That's
what happens in the fall when chlorophyll disappears and other
leaf pigments become visible, creating spectacular fall foliage."
KEITH WELLER (K8717-61
Postdoctoral research scientist Adriana Ortiz-Lopez uses a spectrophoton
examine the different pigments contained in canola seed extracts while pi
physiologist John Whitmarsh prepares a new sample for analysis.
Whitmarsh works collaboratively with
Donald R. Ort, head of the ARS Photosyn-
thesis Research Unit. Their lab experiments
have shown that seed degreening in Arabi-
dopsis-a close relative of canola-mimics
canola's freeze sensitivity. Their goal is to
identify Arabidopsis mutants that develop
little or no seed chlorophyll, as well as other
mutants that display early chlorophyll break-
down during seed maturation.
To check seed degreening, postdoctoral
research scientist Adriana Ortiz-Lopez puts
plants in a growth chamber with freezing air
ed to analyze blowing over them. She also keeps watch
over other plants maintained at above-
freezing temperatures. After a few weeks, she
notes that seeds from plants exposed to
freezing air are green, while those from plants
held at slightly warmer temperatures are brown.
Ortiz-Lopez uses chlorophyll fluorescence to illuminate the
breakdown products of chlorophyll. She's looking for the stage
in the degradation process that is blocked and is hoping to
identify which proteins and genes are involved in chlorophyll
The mutant seeds that degree appear to be more freeze
tolerant. The next step is to identify the modified genes that
are responsible for tolerance to freezing temperatures in
selected mutants. This accomplishment will open the door to
cloning the mutated genes and introducing the freeze-tolerance
genes into a wild plant. Ultimately, transgenic
canola plants can be developed and tested for
freeze tolerance. If successful, plants will
S: produce seeds without chlorophyll, even after
exposure to freezing temperatures.
"Ten years ago, we did the basic research,"
says Whitmarsh. "Now our work demonstrates
the possibility of going from basic molecular
research to an applied solution."-By Linda
This research is part of Plant Biological
and Molecular Processes, an ARS National
Program (#302) described on the World Wide
Web at http://www.nps.ars.usda.gov/
C. John Whitmarsh and Adriana Ortiz-
Lopez are in the USDA-ARS Photosynthesis
Research Unit, University of Illinois,
190PABL, 1201 W Gregory, Urbana, IL
$to 61801-3838; phone (217) 333-2947, fax (217)
aeter o 244-4419, firstname.lastname@example.org. *
Agricultural Research/January 2000
-i. .. ..
. . . . .
New Salmonela Finding
tive form of communication-much as some insects use pheromones to
lure a mate or signal an attack. An Agricultural Research Service scien-
Stist found this happens with Salmonella bacteria, and her discovery could
have big implications for food safety.
Veterinarian Jean Guard-Petter, who is in ARS' Southeast Poultry Research Unit
at Athens, Georgia, found that the food pathogen Salmonella enteritidis uses acyl-
homoserine lactone, or AHL, as its chemical "call to arms."
"This chemical tells cells to rewrite their genetic programming," JEAN GUARD-PETTER (K8732-1)
says Petter. "It enhances their ability to grow as much as a hundred-
fold and signals cells to produce molecules that increase virulence-
the ability to invade living things and cause disease."
Over the last 15 years, occurrences of S. enteritidis food poisoning
have increased fourfold in the United States and fortyfold in Europe.
Better's findings are a first look at how a major foodborne patho-
gen couples heightened growth potential with virulence factors to main- -
tain itself as a food-safety threat.
In an animal host, the bacteria swim along, putting out low levels
of AHL, Petter explains. But once there are a lot of bacteria
concentrated in a confined space-like the spleen of a chicken-the
chemical builds up and signals an aggressive attack, so the next This large bacterial
battlefront-usually a hen's eggs-can be occupied. colony of Salmonella
enteritidis grew rapidly
Salmonella enteritidis in eggs can be a big problem. The infected teridis grew rapidly
I (62 millimeters in
hens don't appear sick, so farmers won't know anything is wrong. diameter in 16 hours)
The contaminated eggs, however, can make people seriously ill. and readily contami-
Fortunately, the new USDA Hazard Analysis and Critical Control nated eggs when given to
chickens by injection but
Points (HACCP) inspection system uses sensitive detection techniques not when givectn by
to keep pathogen numbers as low as possible. mouth.
Petter was the first to see that AHL is a factor in this bacterium's
rapid growth and spread. It was J. Woodland (Woody) Hastings at
Harvard University who, in the late 1960s, discovered that microorganisms can
communicate chemically. Scientists call the phenomenon quorum-sensing.
Petter made her discovery by using a special plasmid reporter system developed
at the University of Nottingham in England. This reporting system puts genes in S.
enteritidis bacteria that cause them to emit light if they are producing AHL. The
theory was that as the light came on and got brighter, growth to a high cell density
would happen at the same time.
The samples showed this was happening. Now, Petter is working with ARS micro-
biologist Amy Charkowski in Albany, California, to understand the chemical structure
Petter theorizes that egg contamination is a cooperative effort by two forms of S.
enteritidis produced by certain strains. The first are "scout cells" that are ingested by
hens and move from the gut to the spleen. Scout cells can't infect eggs any better
than common Salmonella strains. But they blaze a trail for a second type of the bac-
terium that is very good at producing AHL and growing to unexpectedly high levels
within the body of the bird.-By Jill Lee, formerly with ARS.
This research is part of Food Safety, an ARS National Program (#108) described
on the World Wide Web at http://www.nps.ars.usda.gov/programs/appvs.htm.
Jean Guard-Petter is with the USDA-ARS Southeast Poultry Research Laboratory,
934 College Station Rd., Ail ii GA 30605; phone (706) 546-3446, fax (706) 546-
3161, email@example.com. *
KEITH WELLER (K8650-9)
Entomologist Michael McGuire examines biodegradable pesticide-treated spheres in an apple orchard.
Agricultural Research/January 2000
In New England, apples on about 95 percent of unsprayed trees
are typically damaged by apple maggots.
J ust as appearances can be de-
ceiving, so can taste buds be
fooled. A case in point: apple
maggot flies that fall for a bio-
degradable decoy baited with
sugar and laced with insecticide.
The people responsible for the taste
bud trickery are Agricultural Research
Service scientists and university and in-
dustry cooperators who designed the
fatal attractions to be unattractive to
many nontarget creatures. The scientists
say similar decoys can be tailor-made
for other insect pests closely related to
the apple maggot fly.
"In small and large orchards alike, we
want apple maggots to get their just des-
serts in an environmentally friendlier
way than they would with repeated
spraying of trees," says Michael R.
McGuire. He heads the Bioactive Agents
Research Unit at the ARS National Cen-
ter for Agricultural Utilization Research
(NCAUR) in Peoria, Illinois.
From time immemorial, apple mag-
got flies, Rhagoletis pomonella, have
flitted among apple, pear, cherry, and
other rose family species in the eastern
and midwestern United States.
If not controlled, apple maggot flies
can inflict millions of dollars in damage
to orchards. They feed on honeydew
excreted by other insects and then lay
eggs just beneath the apples' skins. Mag-
gots hatch and feed, creating tunnels
through the apples, which begin to de-
cay and drop to the ground. In New En-
gland, apples on about 95 percent of
unsprayed trees are typically damaged
by apple maggots.
Commercial growers usually control
infestations by spraying the trees with a
chemical insecticide about three times
during the growing season, says Ronald
J. Prokopy, an entomologist at the Uni-
versity of Massachusetts, Amherst. Con-
trolling the pest with an insecticide-laced
decoy would leave the apples free of in-
KEITH WELLER (K8653-11
Painting the apple decoy is an essential step
in the production of this insect control
device. Above, technician Erica Bailey
applies the final coat of paint that provides
the appropriate color to attract the apple
To Build a Better Decoy
Prokopy found that the 1/4-inch-long,
black-and-white-striped adult fly was be-
guiled by a decoy with suitable color,
shape, size, and surface texture. Red is a
favorite color, but the latest decoy ver-
sions are another favorite: black. Neither
reflects ultraviolet light. Visually hom-
ing in on an apple decoy, the fly lands,
and its feet detect the sweetness of sug-
ar and sticky high-fructose corn syrup.
While stuck on the sweet stuff, the fly
eats a hearty fill of sugar-along with
whatever insecticide is mixed in.
Before Prokopy sought ARS collab-
oration, his decoys were red wooden
spheres coated with a captivating sticky
substance. Hung in trees, those spheri-
cal death traps worked well until they
accumulated so many captured flies they
lost their effectiveness. Weekly cleaning
and recoating of decoys proved labor in-
Then Prokopy modified the wooden
decoys. He coated them with a concoc-
tion that included sugar and red latex
paint, along with much smaller amounts
of imidacloprid-an insecticide with low
toxicity to mammals-than would nor-
mally be sprayed on trees. Those decoys
worked well until heavy rains quickly
washed much of the sugar away.
That's where ARS scientists in Peo-
ria came in.
Funded partly by the Peoria-based
Biotechnology Research and Develop-
ment Corporation (BRDC), the research-
ers had developed expertise in produc-
ing starch formulations that controlled
the rate of release of various substances.
Coming up with a formulation with the
right features for apple decoys involved
working with BRDC chemist Baruch S.
Shasha, formerly with ARS.
ARS, BRDC, and the University of
Massachusetts have been granted a
patent on the improved biodegradable
decoy. Its inside consists of table sugar,
high-fructose corn syrup, water, corn
flour, and sorbic acid, an anti-mold agent.
Outside is a coating of sugar, latex enam-
el paint, and an insecticide such as imi-
dacloprid. To prevent consumption by
wildlife and other unintended victims,
the researchers have include a hefty dose
of hot cayenne pepper, which the apple
maggot flies don't mind.
Some of the feeding stimulant-the
sugar-still rinses out with each rain,
leaving microscopic pores in the paint.
But as the soaked sphere dries, sugar
from inside is drawn through the pores,
recharging the surface. Recharging with
the insecticide is not needed, since it's
insoluble in water and little washes off.
Preliminary field tests showed the
decoys maintained 70 percent of their
insect-killing power after 11 weeks in
Agricultural Research/January 2000
Massachusetts orchards. And in other
tests, Prokopy and his colleagues found
that once similar decoys were in place,
they protected apples as well as three
applications of the commonly used in-
Aware of the decoys' effectiveness in
Massachusetts, Mark E. Whalon and
Oscar E. Liburd, entomologists with
Michigan State University at East Lan-
sing, wanted to try them in Michigan
orchards. They required 300 of them for
placement about 27 feet apart.
"We realized then that we soon need-
ed to find a way to mass-produce them,"
The Nitty Gritty of Scale-Up
Chemical engineer J.L. Willet, who
heads NCAUR's Plant Polymer Re-
search Unit, began designing a continu-
ous extrusion process to blend the
formulation and make the decoys. To do
this, he needed spherical stainless steel
molds. But considering the fairly small
numbers of spheres needed for the
experiments, purchase of the molds
would greatly drive up the cost per unit.
Then, while at a local fast-food res-
taurant, NCAUR entomologist Robert
W. Behle noticed hollow plastic balls in
a children's area and acquired a few from
the manager. The balls worked sat-
isfactorily as molds. The re-
searchers bought hundreds,
filled them with the extrud-
ed formulation, cooled
them, stripped away the
plastic, and applied an out-
er coating of latex paint.
Supplied with their 300 de-
coys in 1998, the scientists at
Michigan State University, with
colleagues at Kalamazoo College, Kala-
mazoo, Michigan, and the University of
Massachusetts were ready to begin. Co-
operators included the Michigan apple
industry and growers of other fruits
threatened by Tephritidae family rela-
tives of the apple maggot.
In the Michigan field tests, more than
half the attracted apple maggot flies suc-
cumbed immediately, falling to sticky
Chemical engineer J.L. Willett (right) feeds corn-flour-based stock into an extruder as
entomologist Robert Behle assists with the spherical mold during experimental production
of apple decoys for controlling apple maggot flies.
Agricultural Research/January 2000
Plexiglas panes beneath the decoys-to
be counted among the dead. Liburd
concluded that most others became
deathly ill. The evidence: Commercial
monitoring traps just 2 meters away cap-
tured only about one-fifth as many flies
as traps placed near decoys that
lacked only insecticides.
In other Michigan tests,
blueberry maggot flies
fell victim to insecticide-
treated spheres painted
This year, scientists
called for thousands of the
decoys, to continue research
on blueberry and apple maggot
flies and to begin experiments involv-
ing the walnut husk fly in California and
the cherry fruit fly in Washington and
Oregon. The test decoys were made by
the Shady Corporation in Philo, Illinois,
using a production process slightly mod-
ified by Jim Payne.
Commercial manufacture and sale of
the decoys containing pesticides regis-
tered for use in the United States would
require approval by the U.S. Environ-
mental Protection Agency.
ARS is seeking an industrial co-
operator to produce decoys for larger
scale tests. A cooperative research and
development agreement might entail
temporary use of a company's scaled-
up research equipment in a recently ren-
ovated NCAUR pilot plant.-By Ben
This research is part of Crop and
Commodity Pest Biology, Control, and
Quarantine, an ARS National Program
(#304) described on the World Wide Web
Michael R. McGuire is in the USDA-
ARS Bioactive Agents Research Unit,
National Center for Agricultural Utili-
zation Research, 1815 N. University St.,
Peoria, IL 61604; phone (309) 681-
6595, fax (309) 681-6693, e-mail
D ales-those ,.eei. che\w\.
fiber-packed fruits-may be
making a comeback in Cali-
fornia, thanks to sustainable
agricultural practices that have improved
In recent years, growers began notic-
ing a decline in date fruit quality and
suspected it was because the trees were
aging. Looking for help, growers called
ARS plant physiologist ArefAbdul-Baki.
He discovered that it wasn't the trees that
needed help, but the soil.
Abdul-Baki, with ARS' Vegetable
Laboratory in Beltsville, Maryland, has
been active in helping vegetable grow-
ers learn about the value of sustainable
cover crops. He's shown them how to
improve crop yields and reduce produc-
tion costs by adopting a system in which
cover crops improve soil quality by add-
ing organic matter, fixing nitrogen, and
recycling nutrients. Although vegetable
growers are evaluating his system, it
hasn't been used in date orchards.
In 1997, he and date growers teamed
up on a study in California's Coachella
Valley in collaboration with USDA's
Natural Resources Conservation Service
and the California Date Commission.
"Farmers thought old trees were the rea-
son for declining fruit quality, but some
60-year-old trees are still very produc-
ti\e.'" -a\, AbduI-Bakj
He adds, "Our results from an exten-
sive soil profile study of date orchards,
covering about 1,400 acres, reveal many
orchards are suffering from poor nutri-
tion and compacted soil. Soil compac-
tion prevents roots from pushing down
deep into the soil profile. Roots are un-
able to get the amount of water and nu-
trients they need."
Growers are working to correct this
problem by adopting Abdul-Baki's no-
tillage system. They planted two legume
cover crops-Lana vetch and Clay Iron
cowpeas. Lana vetch is planted in the
fall and reseeds itself. The cowpea crop
is grown in the spring and must be re-
seeded each year.
Both cover crops fix a lot of nitrogen
and produce high yields of biomass that
serve as organic matter to enrich the soil.
Abdul-Baki says this no-tillage system
reduces cultivation and production costs,
loosens compacted soils, adds organic
matter, recycles nutrients, and reduces
soil temperature. High soil temperature
stresses roots, he explains.
All is going well in the study thus far,
but it takes about 5 years to see the full
benefits of a sustainable no-tillage sys-
tem, Abdul-Baki points out.
"We've changed the way we manage
our soils and have improved fertilizer
use," says Albert P. Keck, vice chair of
the California Date Commission in Indio,
California. "We know significant chang-
es take time. So far, we're pleased and
are hoping these orchards will bear more
fruit in the future."
As a result of Abdul-Baki's work in
California, about 5,000 acres in the
Coachella Valley are incorporating cover
crops into vegetable and fruit production.
About 90 percent of U.S. dates come
from California; the rest are produced in
Arizona. The industry is small. Annual
production is about 24,000 tons and is
valued at about $62 million annually. The
research could help growers stay com-
petitive-particularly with foreign date
producers.-By Tara Weaver-Missick,
This research is part of Crop Produc-
tion, an ARS National Program (#305)
described on the World Wide Web at
Aref Abdul-Baki is located at the
USDA-ARS Vegetable Laboratory, Bldg.
10A, 10300 Baltimore Blvd., Beltsville,
MD 20705-2350; phone (301) 504-5057,
fax (301) 504-5555. *
Agricultural Research/January 2000
Vitamin K: Another Reason
To Eat Your Greens
SCOTT BAUER (K8691-1)
worldwide, only a handful L
of researchers study vi-
tamin K-long known
V for its critical role in
blood clotting. But with the aging of the .i
U.S. population, this vitamin may com-
mand a bigger following as its impor-
tance to the integrity of bones becomes
increasingly clear. It activates at least
three proteins involved in bone health,
says Sarah Booth. She is in the Vitamin
K Laboratory at the Jean Mayer USDA
Human Nutrition Research Center on
Aging at Tufts University in Boston. i:
"Not too long ago," Booth says, "it
looked like Americans consumed several
times the recommended dietary allow-
ance for vitamin K. But improved
analytical methods show that the vitamin
isn't as abundant in the diet as once
thought." The RDA is 65 gg (micro-
grams) per day for adult females and 80
gg per day for adult males.
Many People Get Too Little
A recent survey Booth conducted in
collaboration with the Proctor & Gamble
Company supported what she had seen
in an earlier study of U.S. diets by the
vitamin K lab. If you're between the ages
of 18 and 44, there's a good chance you
didn't get enough vitamin K today-or
any other day.
She and her colleagues estimated vi-
tamin K intake from 14-day food intake
diaries of a nationwide sample of about
Phylloquinone, the most common
form of vitamin K, was the researchers'
benchmark for vitamin K intake.
"People over age 65 consumed more
phylloquinone than those in the 20 to 40
age bracket," she says. Only half the fe-
males age 13 and over and less than half
the males got the RDA, she notes. "This
confirms there are very low intakes na-
Booth says recent evidence suggests
the current RDA may not be sufficient
for maximizing vitamin K's function in
bones. The vitamin adds chemical
Nutritionist Sarah Booth (right) and technician Molly Damon review an HPLC
chromatogram that shows phylloquinone and dihydrophylloquinone in human plasma.
Vitamin K analysis is conducted under yellow light because the nutrient is sensitive to
entities called carboxyl groups to
osteocalcin and other proteins that build
and maintain bone. Exactly how much
vitamin K is needed to optimize this
function is still being established.
Phylloquinone is found in some oils,
especially soybean oil, and in dark-green
vegetables such as spinach and brocco-
li. For instance, one serving of spinach
or two servings of broccoli provide four
to five times the RDA of phylloquinone.
Most of the survey respondents also
consumed another form of vitamin K-
during the hydrogenation of oils. About
half of U.S. soybean oil is hydrogenated,
according to the Institute of Shortening
and Edible Oils in Washington, D.C. The
degree of hydrogenation ranges from
light, for margarines, spreads, and cook-
ing oils used in restaurants, to heavy, for
deep frying and bakery products.
Booth says that as much as 30 per-
cent of total vitamin K intake may come
in the form of dihydrophylloquinone, but
it is less biologically active than phyllo-
quinone. In fact, it was half as active with
a clot-forming protein and was complete-
ly inactive with a bone-forming protein.
"So hydrogenated oils shouldn't be con-
sidered an important source of vitamin
K," she emphasizes.
Agricultural Research/January 2000
Veggies vs. Oils
What is the best source of vitamin K?
Vegetables provide the lion's share of this
vitamin in the diet. But nutritionists have
assumed that people absorb more from
oil or oil-based supplements than from
To find out, Booth led a study with
colleagues at Yale University School of
Medicine to compare the absorption and
use-known as bioavailability-of
vitamin K from broccoli and from oil
fortified with the vitamin. For 5 days
each, volunteers consumed a helping of
broccoli or fortified oil along with a base
diet. This increased their phylloquinone
intake to around 400 tg/day-five to six
times the RDA.
"What's really exciting," Booth says,
"is to look at the functional markers for
vitamin K status. There were no differ-
ences between vitamin K from broccoli
and vitamin K from oil overall. That's
good because green leafy vegetables con-
tain so many other nutrients."
For instance, when the volunteers ate
broccoli, blood levels of an important
to when they ate the base diet only.
Booth says scientists are now using
different measures of vitamin K status
because the traditional yardstick-blood
coagulation time-is not sensitive
enough to detect changes in status. So the
researchers relied on changes in plasma
phylloquinone levels and two functional
One functional marker is the bone-
building protein osteocalcin. To be fully
active, it must be saturated with carbox-
yl groups, and that's vitamin K'sjob. So
the researchers looked for changes in sat-
uration in the osteocalcin. After 5 days
of eating broccoli or oil fortified with
vitamin K, says Booth, more osteocalcin
was saturated with carboxyl groups.
The second functional marker-uri-
nary Gla-didn't change. Short for gam-
ma carboxyglutamic acid, Gla indicates
overall vitamin K activity in the body.
Its lack of change was expected, says
Booth, because the supplementation pe-
riod was short. She has since found that
it takes 10 days on the same diet to cause
a change in urinary Gla.
Phylloquinone in blood plasma in-
creased as expected. Booth says chang-
es in plasma levels help show recent
changes in intake. But they are not good
markers of long-term vitamin K status
because they fluctuate according to the
Older and Younger Adults Benefit
The study included 18 older men and
women and 18 younger volunteers to see
whether bioavailability changes with age.
There was no difference between the 20-
to 40-year-old group and the 60- to 80-
year-old group. This surprised the re-
"Older people tend to have higher
blood levels of phylloquinone," explains
Booth, "so we thought they might not
respond to dietary increases as much as
the younger group.
"Instead, the study showed that older
people can get just as much benefit from
increasing vitamin K intake." And that's
good news because there is some
evidence that hip fractures may be
associated with lower saturation of
osteocalcin.-By Judy McBride, ARS.
This research is part of Human Nu-
trition, an ARS National Program (#107)
described on the World Wide Web at
Sarah L. Booth is at the Jean Mayer
USDA Human Nutrition Research Cen-
ter on Aging at Tufts University, 711
Washington St., Boston, MA 02111;
phone (617) 556-3231, fax (617) 556-
3149, e-mail firstname.lastname@example.org. *
SCOTT BAUER (K8692-2)
Dietitian Judy Lee instructs study
volunteer Sheila Wolf on the foods to be
eaten as part of the metabolic study.
Agricultural Research/January 2000
These ears of corn demonstrate some of the different mutations maintained at the Maize
Genetics Cooperation Stock Center.
One day in 1959, University
of Illinois scientist John
Laughnan absentmindedly popped dry
corn kernels into his mouth while
shelling mutant seeds off cobs. He was
surprised by the sweetness of one of the
kernels from a particular mutant ob-
tained from the university's Maize
Genetics Cooperation Stock Center in
That particular mutant was known as
shrunken2. Its shriveled-up kernels
became what the world now knows as
Sweet corn with this trait holds its
sweetness, whereas traditional sweet
corn with the sugary trait loses its
sweetness rapidly after picking. In 1998,
commercial sweet corn, which is now
mostly shrunken2-both for fresh mar-
ket and processing-was worth about
The shrunken2 mutant is just 1 of
more than 3,000 stored and maintained
at the stock center.
"The mutants in this collection
provide maize scientists with a wealth
of knowledge about corn as a biological
organism," says Martin M. Sachs.
Director of the center, he is a maize
geneticist with the Agricultural Re-
search Service, which operates the
center at the University of Illinois. "This
knowledge can lead to applications that
may improve corn agronomically and
bring tastier and more nutritious food to
our dinner tables," he says.
Sachs entertains visitors by pulling
out corn oddities from a plastic "shoe
box" and telling corn riddles like this
one: "Ever wonder how corn chips at the
health food store got their purplish-blue
"They're derived from purple ears of
corn, and the purplish color was selected
by early Native American breeders for
ornamental and religious purposes,"
Sachs explains. "In the High Andes of
South America, this purple color was
selected for expression in plant tissue and
was thought to protect corn from the
sun's ultraviolet rays."
Getting Back to Basics
Most of the mutants in the collection
are used mainly for basic research. This
is important, says Sachs, because maize
is highly regarded as a test organism for
certain genetic studies. The collection
represents the working stocks for maize
geneticists and provides a service simi-
lar to that provided to chemists by a
chemical supply house.
The idea of the Maize Genetics
Cooperation Stock Center was born in
1928. At that time, the "father" of maize
genetics, Cornell University professor
Rollins A. Emerson, met with a few
maize workers in a New York hotel room
and discussed maize linkage maps.
The center was originally located at
Cornell University. The stocks were
transferred to their present Illinois home
in 1953. Today, the collection at the stock
center is considered an international trea-
While most of the mutants are too
extreme for commercial breeding, a few
have affected the marketplace. Stock
center researchers have discovered useful
traits, such as those that affect starch
quality and abundance of the amino acid
lysine, which are important in animal
Agricultural Research/January 2000
"The mutants in this collection provide maize
scientists with a wealth of knowledge about corn
as a biological organism."-Martin M. Sachs
feed. The Archer Daniels Midland
Company of Decatur, Illinois, uses the
product of a mutant from this center for
producing its pure amylopectin, a
branched starch that is an important
ingredient in human foods.
Some mutants produce seedlings with
varied colors: yellow, albino, purple,
golden, or striped. Others bear odd-
shaped ears, such as one that looks like
an onion bulb or another that is branched,
with a tassel resembling a Christmas tree.
The total collection has about 80,000
individual samples. The majority of the
stocks are maintained so they can be used
for specific research purposes.
KEITH WELLER (K8710-1)
Maize geneticist Martin Sachs observes the
branched tassel trait of romosal mutant
The Source of This Diversity
Maize geneticists and breeders around
the world have submitted the bulk of the
genetic variations and aberrations. But
most of the chromosomal aberrations in
the stock center were deliberately in-
duced by radiation during atomic bomb
tests in 1946 and 1948, in an experiment
to observe its effects on living organisms.
Important contributions in assembling
and maintaining stocks of chromosomal
aberrations have been made by Univer-
sity of Missouri, Iowa State University,
and Indiana University scientists. Others
were generously submitted by farmers
and breeders who found them in their
Maintaining the collection isn't an
easy chore. Seed samples are increased
by hand planting, pollination, and har-
vesting of each ear individually. Ears are
shelled individually, too, and seed sam-
ples from each ear are stored in packets
and labeled with genetic symbols. For
long-term storage, the cold room is kept
at 45 OF with less than 30 percent rela-
Toward Flood-Tolerant Corn
When he has time, Sachs is able to
pursue an important research interest:
how corn responds to oxygen depriva-
tion-which is what happens when wa-
ter is standing in a field.
In 1989, he started identifying va-
rieties with tolerance to drowning, while
he and his colleagues screened over
1,000 North American and Latin
American corn lines for flood tolerance.
A genetic trait for submergence tolerance
could help U.S. corn withstand anaerobic
stress from loss of oxygen while under
water-giving farmers another kind of
Over the years, Sachs has identified
10 different breeding lines that show a
simple dominant trait for increased flood
tolerance. He found the flood-tolerant
corn while screening 400 genetic land
races from the International Maize and
Wheat Improvement Center in Mexico
City. The fate of the 10 selected lines: to
have their seedlings completely sub-
merged long enough that the submer-
gence would kill normal corn seedlings.
One mutant was found to be so sensi-
tive that its seedlings died within hours.
But a few of the more tolerant varieties
survived up to 6 days. The vast majority
of corn lines survive 3 days of flooding
under experimental conditions.
For now, Sachs uses traditional breed-
ing techniques to cross the desired trait
into American corn lines. But he envi-
sions that genetic engineering will allow
him to someday fortify corn with even
more flood tolerance from rice.
It will still be several years in the fu-
ture before Sachs has made the necessary
genetic improvement in water-tolerant
corn lines. But someday, seed breeders
will benefit from this work-just as
today's consumers have benefitted from
sweet corn derived from shrunken 2.-
By Linda McGraw, ARS.
This research is part of Plant, Micro-
bial, and Insect Genetic Resources, Ge-
nomics, and Genetic Improvement, an
ARS National Program (#301) described
on the World Wide Web at http://
Martin M. Sachs is at the USDA-ARS
Maize Genetics Cooperation Stock Cen-
ter, University of Illinois, S-123 Turner
Hall, 1102 S. Goodwin Ave., Urbana, IL
61801; phone (217) 333-6631, fax (217)
333-6064, e-mail email@example.com.
Visit the Maize Genetics Cooperation
Stock Center web page at http://
KEITH WELLER (K8713-1)
Agricultural Research/January 2000
lll !(3JU, -. li~ l ..;: .. i -.... .- -..... ..... : = =-' -- '; = :
PEGGY GREB (K8706-7)
planted cotton in wide rows
about 30 to 40 inches apart.
Their choices were limited, as
was their equipment, which was
usually just a mule-driven plow.
Today, farmers are experimenting
with planting cotton much closer togeth-
er, in rows ranging from about 7-1/2 to
10 inches wide. Research is under way
at ARS locations to make production of
this ultra-narrow-row (UNR) cotton
more economical for farmers.
"With UNR cotton, a farmer can
plant more rows and potentially harvest
more cotton per acre," says William T.
Molin, a plant physiologist with ARS'
Southern Weed Science Research Unit
in Stoneville, Mississippi. "Also, since
rows are planted closer together, cotton
crowds the weeds out, reducing the need
for midseason herbicide applications."
Molin and other ARS researchers are
participating in a 10-year project look-
ing at varying aspects of long-term UNR
cotton production-from managing
weeds to processing.
"There's not enough solid informa-
tion on UNR cotton available to farm-
ers," says Molin. "So they are either
growing UNR cotton and seeing what
works best, or they are avoiding it alto-
gether because of lack of information."
In 1998, Molin began field studies on
40 acres to compare UNR cotton with
conventional cotton. "We grew 12 pop-
ular varieties, using both wide and ultra-
narrow rows," says Molin. "Our results
showed the UNR crop was comparable
in yield to conventional cotton."
Molin also looked at key fiber
characteristics of UNR and conventional
cotton. Although the fiber characteristics
are more favorable in conventional
cotton-fibers are longer and less
tangled-he says by improving crop
management and harvesting techniques,
UNR cotton quality should also im-
"We're working toward developing
management systems that will establish
Samples of spindle-harvested, conventionally grown cotton (left) and stripper-harvested
UNR cotton. Cotton harvested with a stripper harvester contains more stems and leaves.
criteria for growing UNR cotton in the
Delta," Molin says.
Conservation practices are important
in growing cotton-a primary cash crop
for early U.S. settlers. As they scurried
to plant more acres in the 1700s, exces-
sive planting allowed more soil erosion
to occur. Now ARS scientists with the
Soil Dynamics Research Laboratory in
Auburn, Alabama, and the Coastal Plains
Soil, Water, and Plant Research Center
in Florence, South Carolina, are helping
farmers put conservation practices that
help prevent soil erosion to work.
For two growing seasons, ARS agron-
omists D. Wayne Reeves and Philip J.
Bauer conducted a study to look at the
effects of residue management and ni-
trogen fertilization on UNR cotton in
Auburn and Florence.
"We used conservation tillage prac-
tices in ultra-narrow-row cotton," says
Reeves, with the Auburn unit. "The cot-
ton was grown on Coastal Plains soils
that are typically sandy, subject to soil
compaction, and unproductive for row
crops like cotton."
Bauer adds, "We found the rate of
nitrogen fertilizer for UNR cotton should
be between 60 and 80 pounds of nitro-
gen per acre-about the same as for
conventional-row-width cotton on these
soils." He says that when cotton is
planted after a legume cover crop, less
nitrogen fertilizer is needed.
Another study using cover crops re-
vealed a 60 percent higher lint yield when
UNR cotton followed a cover crop of
black oats or wheat, compared to con-
ventionally planted cotton in 40-inch
rows. Merging the UNR system with
modern conservation technologies and
using cover crops can reduce crop pro-
duction inputs, conserve soil and mois-
ture, and improve yields, says Reeves.
Examining Fiber Quality
Many farmers are concerned about the
possible lower quality of UNR cotton.
Researchers in the ARS Southern
Regional Research Center's Cotton Fiber
Quality Research Unit, at New Orleans,
Louisiana, are trying to ease their
Plant physiologist Judith M. Bradow's
specialty is scrutinizing the properties
Agricultural Research/January 2000
that make cotton fiber the prized com-
modity it is today. Bradow and col-
leagues did side-by-side comparisons of
UNR and conventional cotton fibers.
Though their work is still preliminary,
the scientists are finding few if any dif-
ferences in lint fiber properties, unless
it is harvested with a stripper harvester.
When a stripper is used, unwanted
trash gets mixed into cotton. "Trash is
primarily sticks-the stems that help
support the bolls-and leaves that don't
fall off the plant," explains Bradow.
"Fiber properties start going downhill
when you use the stripper harvester.
Once trash gets stuck to the fiber, it
doesn't come off easily," he says.
Farmers use stripper harvesters
primarily for UNR cotton. Fingers or
brushes strip plant parts and cotton bolls
from the plant, thus picking up excess
trash. "This is a negative aspect of har-
vesting UNR cotton, particularly for
ginners," says W. Stanley Anthony, an
agricultural engineer with ARS' Cotton
Ginning Research Laboratory in
Most conventionally grown cotton
uses a spindle harvester that has many
rotating barbed spindles. The spindles
grasp the fiber and selectively pull it out
of the boll, leaving unwanted plant parts
or trash behind. Spindle harvesting
yields about 100 pounds of trash per bale
compared with 400 pounds of trash per
bale from stripper harvesting. A bale is
500 pounds of fiber.
In a 1998 gin study, Anthony found
that UNR cotton quality measured up to
that of conventionally grown cotton
based on traditional grading. He evalu-
ated cotton grown at 10 locations in the
South and Southeast.
Anthony says that when additional
cleaning machinery was used for the
UNR cotton at the gin, the grades of
UNR cotton were equivalent to those of
conventional cotton. But since more gin
machines are used and more material
must be processed, it costs more to gin
UNR cotton, and the fiber suffers more
damage-mainly in the form of increased
neps and shorter fibers.
Cleaning Is the Key
Once the UNR cotton was ginned at
Stoneville, Anthony sent it to ARS'
Cotton Quality Research Unit at
Clemson, South Carolina, where it was
processed at the pilot spinning plant.
Initial evaluation by textile researcher
David McAlister showed minimal
disadvantages during textile operations.
"Our 1998 study showed only minor
differences in fiber properties between
UNR and conventionally grown cotton,"
says McAlister. "However, the differenc-
es in fiber properties did not affect the
quality of the yar." He's hoping their
research will help cotton mills understand
how to process and handle UNR cotton.
Supporting this evidence, a previous
study conducted at Clemson gave now-
retired ARS scientist Charles K. Bragg a
clue as to how UNR cotton might act in
textile processing. He says that limited
preliminary experiments suggest UNR
cotton does not act differently than stan-
dard conventional cotton.
UNR in Other Regions
V.T. Walhood, in Shafter, California,
who has since retired, conducted pio-
neering experiments in the 1960s through
1980s on the growth and yield of ultra-
narrow-row cotton. His experiments
showed that planting three rows of early-
maturing cotton in the space normally
allocated for one row of a mid- to late-
season cotton produced the same yield
and gave a bonus: They harvested the
early cottons before populations of pink
bollworms had a chance to build up to
Another Shafter scientist, Angus Hyer,
included narrow-row cottons in his
research nursery of more than 150 experi-
mental lines. When he offered his
experimental cottons, with features such
as improved resistance to insects or
diseases, to commercial breeders in the
Cotton stripper harvesting UNR cotton
near Altha, Florida.
UNR cotton planted into a cover crop of
black oats. Narrower rows promote canopy
closure in just 33 days, helping to reduce
erosion and control weeds.
late 1980s, most U.S. cotton seed compa-
nies tried some.
Several years after Hyer's death, F.
Douglas Wilson, a collaborator at ARS'
Western Cotton Research Laboratory,
Phoenix, Arizona, scrutinized Hyer's
collection to make sure the best-
performing lines made their way safely
into ARS genebanks as permanent
resources for breeders worldwide.
At Lubbock, Texas, ARS scientists in
the Cotton Production and Processing
Research Unit are also conducting
experiments comparing yield and fiber
quality of UNR versus conventional
cotton using two varieties. ARS agri-
cultural engineer Alan D. Brashears
harvested 40-inch-row cotton and
narrow-row cotton. "Our preliminary re-
sults showed there wasn't much dif-
ference in quality or yield between UNR
and conventional cotton," he says.
Soil scientist R. Louis Baumhardt, at
ARS' Conservation and Production
Agricultural Research/January 2000
Research Laboratory in Bushland, Texas,
is testing whether UNR cotton can be
grown in the northern Texas Panhandle.
Farmers in this area usually don't grow
cotton because yields are low from cooler
temperatures and a shorter growing
season. Instead, they grow grain sorghum
and wheat with rest periods in between.
However, by using new early-season
cotton varieties and by growing more
plants per acre, farmers could boost
cotton yields enough to make the crop
more profitable than wheat.
The Bottom Line Is Profits
With low commodity prices and tough
international competition, farmers are
looking hard at the economics of grow-
ing cotton. Current information about
the economics of UNR cotton produc-
tion is lacking. Martin Locke, head of
the Southern Weed Science Research
Unit, and Ray Williford, head of ARS'
Application and Production Technolo-
gy Research Unit in Stoneville, began
cooperative studies this year to evalu-
ate UNR cotton in various tillage and
Results from these and other stud-
ies could mean a promising future for
UNR cotton.-By Tara Weaver-Mis-
sick, Hank Becker, Don Comis, Jan
Suszkiw, and Marcia Wood, ARS.
This research is part of Soil Re-
source Management (#202), Integrat-
ed Farming Systems (#207), Crop
Protection and Quarantine (#304),
Crop Production (#305), and New
Uses, Quality, and Marketability of
Plant and Animal Products (#306),
ARS National Programs described on
the World Wide Web at http://www.nps.
Scientists mentioned in this story
can be contacted through Tara
tion Staff, 5601 Sunnyside Ave.,
Beltsville, MD 20705-5129; phone
(301) 504-1619, fax (301) 504-1641,
e-mail firstname.lastname@example.org. *
WILLIAM MOLIN (K8720-1)
Agricultural Research/January 2000
~Ljl/~f~ q if; q 7 4.... '% rL~c.r~
Chesapeake Bay Day
ARS held the first Chesapeake Bay
Day at Beltsville, Maryland, last Septem-
ber 28. Among the research featured was
work on finding out if pasteurization kills
microbes in cow manure. Equipment lent
by N-Viro, International, of Toledo, Ohio,
may show whether pasteurization kills
Escherichia coli, Cryptosporidium
parvum, and other pathogens that can
lurk in manure. It mixes manure with
recycled materials like cement or lime
kiln dust, coal ash from electric power
plants, and gypsum. The experiment will
compare pasteurization with composting,
assessing both systems for odor control
and effectiveness in killing disease-
causing organisms. Researchers want to
see if pasteurization will convert
phosphorus in manure to a form less
likely to leach into streams and rivers.
They will also test materials such as alum
for their ability to stabilize phosphorus
in manure. If the experiment works, it
could help prevent the escape of
phosphorus and pathogens in farm runoff
and provide a safe outlet for two
materials found in excess in Chesapeake
Bay coastal areas: high-phosphorus
chicken litter and harbor dredging spoils.
Patricia D. Millner, USDA-ARS Soil
Microbial Systems Laboratory, Beltsville,
Maryland; phone (301) 504-8163, e-mail
What Hispanic Americans
Public health professionals, research-
ers, educators, and dietitians serving the
Hispanic community can now spot
dietary patterns that could affect health.
That's thanks to the 1994-96 What We
Eat in America Survey (also known as
the CSFII) that inventoried food and
nutrient intakes. The data show that
Mexican Americans eat more fiber than
other Hispanics, non-Hispanic whites,
and non-Hispanic blacks-17 grams
daily, on average, for all Mexican
Americans. This is closer than the other
groups to the 20 to 30 grams recom-
mended by the National Institutes of
Health. Adult Mexican American males
age 20 and over consumed nearly 24
grams of fiber on average, while teenage
males consumed nearly 20.
Legumes may contribute a large
portion of that fiber, since adult Mexican
American males averaged 107 grams of
legumes a day and teenage males, 71.
That's double the intake of other
Hispanics and almost four times that of
non-Hispanic groups. Not surprisingly,
Mexican Americans eat more tortillas
and taco shells than other Hispanics-
about twice as many-while the latter
group eats three times more rice. Sixty-
three percent of the milk consumed by
Mexican Americans is whole (rather than
low-fat alternatives), compared to 59
percent for other Hispanics, 70 percent
for U.S. blacks, and 25 percent for
whites. In 1994-96, both Hispanic groups
were low in the same nutrients as the
general population, with intakes of
vitamin E, calcium, and zinc below
Recommended Dietary Allowances.
Blacks also fell below the RDA for
magnesium. Katherine Tippett, USDA-
ARS Food Surveys Research Group,
Beltsville, Maryland; phone (301) 504-
0170, e-mail email@example.com.
The raw survey data are available on
CD-ROM from the National Technical
Information Service at 1-800-553-6847
(Accession No. PB98-500457). Data
tables can be viewed on the USDA's
Food Surveys Research Group web site
Collaring Deer Ticks To
Reduce Lyme Disease
An automatic device that puts a pes-
ticide-impregnated collar around a
white-tailed deer's neck may help reduce
Lyme disease in the Northeast and help
control cattle fever ticks along the Tex-
as-Mexico border. Lyme disease is the
most prevalent tickborne human disease
in the United States, with about 90 per-
cent of the cases reported to the Centers
for Disease Control and Prevention oc-
curring in northeastern states.
Pesticide collars are commonly used
for controlling ticks and other parasites
on domestic animals. But until now,
collaring wildlife has meant trapping or
tranquilizing the animals. The new
collaring unit, patented by Agricultural
Research Service scientists, lures deer to
a specially designed feeder. To eat, an
animal must place its neck near the
collaring mechanism, which releases a
flexible, self-adjusting collar similar to
flea collars worn by cats and dogs. ARS
researchers in Kerrville, Texas, who
tested the collars on captive deer, found
no ticks attached and feeding on the
animals. The collars are impregnated
with amitraz, a pesticide approved for
livestock that also kills ticks on deer hair
and skin. If approved for use on deer, it
would be safe to use during hunting
season, from October through Decem-
ber, when most adult blacklegged
ticks-the culprits behind Lyme
disease-are feeding. Further research,
along with a cooperative research and
development agreement with Wildlife
Management Technologies of Noank,
Connecticut, should lead to refinements
of this tick-control method. J. Mathews
Pound, USDA-ARS Livestock Insects
Research Laboratory, Kerrville, Texas;
phone (830) 792-0342, e-mail jmpound
Agricultural Research/January 2000
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