Read the magazine story to find out more.

ARS researchers have been studying plant reactions to changes in C02 levels, from the Ice Age—13,000 to 18,000 B.C.—to the year 2050 A.D. by growing them in long, plastic-covered "time tunnels."

Why invasive plants take over   Elevated carbon dioxide spurs shrub growth   More forage, but less filling

Time-Tunneling for Climate Change Clues

By Don Comis
November 20, 2009

If you look closely at individual plant species' responses in the past, you may find that the largest effects of high carbon dioxide (CO₂) levels occurred decades ago, according to Agricultural Research Service (ARS) scientists. That is when the botanical structure of the world's grasslands changed dramatically, offering clues to the future.

For several years, Wayne Polley and Philip Fay, ecologists at the ARS Grassland Soil and Water Research Laboratory in Temple, Texas, have been studying plant reactions to a gradient of CO₂ levels, from the Ice Age—13,000 to 18,000 B.C.—to the year 2050 A.D. Their research supports the U.S. Department of Agriculture's priority of developing long-range global change strategies.

The ecologists do their research with "time tunnels." These are long, plastic-covered tunnels in which tall prairie grasses are exposed to increasing levels of CO₂. These tunnels are an alternative to traditional open-top outdoor chambers in which plants are exposed to only one level of CO₂ per chamber.

Among their recent findings is that grasses respond to higher CO₂ levels by using water more efficiently. They have been measuring plant water use for four years now, ever since they modified the tunnels by placing them over steel-lined, soil-filled pits with soil-weighing lysimeters to measure soil water loss.

More efficient water use by prairie grasses sounds like a good thing, but weedy shrubs and grasses also benefit from increased water use efficiency. This may help weeds outcompete desirable forage plants. But the cumulative effects of these individual species' responses on plant communities won't be obvious for years.

Read more about this and other climate change research in the November/December 2009 issue of Agricultural Research magazine.

ARS is USDA’s principal intramural scientific research agency.

ARS computational biologist Doreen Ware and colleagues have completed a four-year effort to sequence the genome of corn. Click the image for more information about it.

Corn research unlocks basis of natural diversity   Here's one a-maize-ing website   ARS produces online databases for maize, blueberries.

USDA Scientists, Colleagues Sequence Corn Genome

By Dennis O'Brien
November 19, 2009

WASHINGTON, November 19, 2009—U.S. Department of Agriculture (USDA) scientists and their colleagues have completed a four-year effort to sequence the genome of corn, an achievement expected to speed up development of corn varieties that will help feed the world and meet growing demands for using this important grain crop as a biofuel and animal feed. The results represent the largest and most complex plant genome sequenced to date, and are the cover story in the November 20 issue of the journal Science.

"Sequencing the corn genome will help researchers in the United States and around the world develop corn varieties to confront critical global challenges like climate change, hunger, and renewable energy," said Edward B. Knipling, administrator of USDA's Agricultural Research Service (ARS), USDA's principal intramural scientific research agency. "This effort will provide scientists a preliminary blueprint for identifying genetic pathways that will lead to a better understanding of corn and enable scientists to improve corn in a number of ways."

The sequencing will help researchers uncover the relationships between corn genes and traits, develop an overall picture of the plant's genetic makeup, and broaden understanding of how the complex interplay of genetics and environment determines the plant's health and viability. The work also is expected to lead to development of corn varieties with higher yields and better tolerance of droughts, pests and diseases. It also should help scientists produce varieties with fibers, stalks and cellular structures that will make corn a better source of biofuel.

The team, which included Doreen Ware, a computational biologist at the ARS Robert W. Holley Center for Agriculture and Health in Ithaca, N.Y., has released the most comprehensive draft sequence to date, providing the most detailed look thus far at the functional portions of the corn genome. Ware led the computational effort and is a lead author of the report along with Richard Wilson of Washington University School of Medicine in St. Louis, Mo., and Patrick S. Schnable of Iowa State University at Ames. Other key participants in the project included the University of Arizona at Tucson and Cold Spring Harbor Laboratory in New York. USDA's National Institute of Food and Agriculture, along with the National Science Foundation and the U.S. Department of Energy, jointly funded the $29.5 million effort.

Edward Buckler, an ARS geneticist at the Holley Center, and Ware also have used next generation sequencing data to assemble a haplotype genetic map of the corn genome that lays out portions of the genome shared by 27 diverse inbred lines of corn. A haplotype is a combination of alleles—alternative forms of genes—that are located closely together on the same chromosome and tend to be inherited together. The corn lines in the haplotype genetic map were selected specifically because they represent the vast majority of the genetic diversity in corn. By searching through these lines, researchers and breeders can unlock corn's genetic potential and significantly accelerate the breeding of plants to meet the demands of the growing world population and the challenges of global climate change. Buckler's "HapMap," which also is published in Science, shows a 30-fold variation in recombination rates, which are the rates that genetic material from parents mix to show up in the progeny. The map is designed to function like the human genome HapMap, making it easier to link genes and genetic patterns with significant traits, Buckler said. The researchers already are linking the HapMap to the basis of hybrid vigor.

Corn, known among scientists as maize, is one of world's most important crops. Corn was a $47 billion crop in the United States last year. It is the largest production crop worldwide, providing not only food for billions of people and livestock, but also critical feedstock for production of biofuels. Ware said the work should serve as a foundation for understanding and improving on other agricultural crops as well. Plants previously sequenced include rice, sorghum, poplar, grape and Arabidopsis thaliana, a plant widely studied as a model organism.

ARS scientists have developed a microwave meter that measures moisture and density of in-shell peanuts faster and easier, both important quality indicators. Image courtesy of Microsoft clipart.

Online peanut warehouse ventilation calculator available   Technology improves peanut grading, moisture detection   Measuring peanuts' moisture—while still in the shell

Microwave Meter Measures Moisture and Density of In-Shell Peanuts

By Sharon Durham
November 19, 2009

A microwave meter that instantaneously measures both moisture and density of in-shell peanuts has been developed by Agricultural Research Service (ARS) scientists, making it easier and faster for producers and processors to determine these important quality indicators.

Moisture content is the most important factor in peanut quality. Kernel moisture content must be less than 10.5 percent, because higher levels can lead to the growth of fungi that produce aflatoxins, which cause illness in animals and humans.

The new apparatus measures density and moisture independently, eliminating an extra testing step and improving an earlier ARS technology that used radio frequencies to determine moisture content.

Using the new technology, peanut graders can determine peanut kernel moisture content with only about 0.5 percent standard error. ARS engineer Samir Trabelsi and retired ARS engineer Stuart O. Nelson, in the ARS Quality and Safety Assessment Research Unit at the agency's Richard B. Russell Agricultural Research Center in Athens, Ga., developed the microwave meter. The method is rapid, nondestructive and eliminates the need for shelling the peanut pods.

In the new process, in-shell peanuts are loaded directly into the sample holder of the microwave meter, and an antenna transmits low-intensity microwaves into the peanut pods. The microwaves pass through the pods and are received by another antenna facing the transmitting antenna. Alterations in the energy level and velocity of the microwaves, as they pass through the pods, reveal moisture content in the kernels and bulk density of the peanut pods. A computer is attached to record moisture and density measurements. For moisture content determination, the new technique also eliminates the need for multiple calibrations and compensates for density and temperature.

The technology has been given a provisional patent and is being tested at five peanut buying stations in Georgia, Alabama and South Carolina.

This research supports the U.S. Department of Agriculture (USDA) priority of ensuring food safety. ARS is USDA's principal intramural scientific research agency.

Nettle moth caterpillar (Darna pallivitta). Click the image for more information about it.

Pesky white peach scale targeted in tropical studies   New USDA research facility to open in Hawaii

Invasive Nettle Moth Triggers Hawaii Research

By Marcia Wood
November 18, 2009

Like children everywhere, kids in Hawaii love to run barefoot through tall grass. But an invasive pest called the nettle moth caterpillar can take the fun out of this simple childhood pleasure, according to Agricultural Research Service (ARS) research entomologist Eric B. Jang.

The sharp, spiky hairs of the caterpillar, Darna pallivitta, can cause a painful, stinging sensation. Besides being a hindrance to childhood play, this agricultural pest poses a hazard to people working with palm plants and other commercially grown ornamentals that the insect attacks.

That's why Jang, who’s at the U.S. Pacific Basin Agricultural Research Center in Hilo, Hawaii, is working with colleagues in that state and elsewhere to explore new ways to thwart the insect.

In a highly experimental approach, Jang plans to use sexually sterilized fruit flies, such as sterilized melon flies, as winged carriers of an alluring nettle moth scent, a component of what's known as a pheromone. Sterile melon flies are a logical choice because techniques for producing large numbers of them—to disrupt their normal reproduction and cause their populations to crash—are already in place.

In theory, sterilized melon flies, each carrying a drop of the nettle moth chemical on its back, could be set free in moth-infested locales in Hawaii to quickly and inexpensively distribute the scent wherever they fly. Like decoys, the melon flies would create confusion among amorous male moths that use the scent to find female moths.

Jang and colleagues have described the concept and pheromone component in published scientific articles. ARS and the State of Hawaii Department of Agriculture have provided funding to Jang and co-researchers to pursue this innovative idea, known as "mobile mating disruption."

Former postdoctoral research associate Matthew S. Siderhurst identified and synthesized the nettle moth pheromone compound in early experiments funded by ARS and the Hawaii Invasive Species Council.

The pheromone component can also be placed in traps to detect the caterpillar and monitor its spread, Jang noted.

ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.

Read the magazine story to find out more.

ARS scientists have found that using alternative types of fertilizers can cut back on greenhouse gas emissions from crop production, at least in one part of the country. Click the image for more information about it.

Organic dairy manure may offer fertilizer option   ARS seeks partner for new environmentally friendly fertilizer   More about no-till and greenhouse gas emissions

Studying Fertilizers to Cut Greenhouse Gases

By Dennis O'Brien
November 17, 2009

Agricultural Research Service (ARS) scientists have found that using alternative types of fertilizers can cut back on greenhouse gas emissions, at least in one part of the country. They are currently examining whether the alternatives offer similar benefits nationwide.

Nitrogen fertilizers are often a necessity for ensuring sufficient crop yields, but their use leads to release of nitrous oxide, a major greenhouse gas, into the atmosphere. Fertilizer use is one reason an estimated 78 percent of the nation's nitrous oxide emissions come from agriculture, according to Ardell Halvorson, a soil scientist at the ARS Soil Plant Nutrient Research Laboratory in Fort Collins, Colo.

Halvorson compared nitrous oxide emissions from corn fields treated with either a conventional nitrogen fertilizer (urea) or either of two specially formulated urea fertilizers—one with "controlled release" polymer-coated pellets, and the other with inhibitors added to "stabilize" the urea to keep more of it in the soil as ammonium for a longer period.

In a two-year experiment at Fort Collins, he collected the emissions using static vented chambers, similar to small "pillbox" structures placed over the soil. He chose a no-till cropping system because it's known to reduce carbon dioxide emissions. He found that the controlled-release fertilizer cut nitrous oxide emissions by a third, and that the stabilized fertilizer cut them almost in half.

Halvorson's results are so far limited to the irrigated fields and cool, semi-arid conditions in and around Fort Collins. But nitrous oxide releases are the result of a complex interplay of conditions that vary from one area to the next, such as soil water content, soil temperatures, soil types, microbial activity, climactic conditions and rainfall patterns. So Halvorson is expanding the study, with support from the fertilizer industry and cooperation of other ARS locations, to see how the fertilizers respond at seven sites around the United States.

The research supports the U.S. Department of Agriculture (USDA) priority of responding to climate change.

Read more about ARS climate change research in the November/December 2009 issue of Agricultural Research magazine.

ARS is USDA's principal intramural scientific research agency.

ARS scientists have found that certain fungi can prevent compounds in grapefruits from interfering with some prescription medicines. Photo courtesy of Florida Department of Citrus.

U.S.-Thai scientific efforts peg guava's nutritional value   Citrus peel waste a potential source of ethanol

Fungi May Hold Key to Reducing Grapefruit Juice Interactions with Medications

By Sharon Durham
November 16, 2009

A fungus may help solve a problem of a grapefruit compound that interacts negatively with certain prescription drugs, according to studies by Agricultural Research Service (ARS) scientists.

Grapefruit contains furanocomarins (FCs), which inhibit the enzymatic activity responsible for metabolizing certain prescribed medications and allowing more of the medication to enter the bloodstream. FCs are phytochemicals commonly found in plants. Two well-known phytochemicals are Vitamins C and E.

Grapefruit juice can interfere with the metabolism of certain medications used to treat a wide range of conditions such as allergies, abnormal heart rhythm, depression, hypertension, infections, heart disease, and high cholesterol. The grapefruit industry may have lost customers who no longer drink grapefruit juice due to their medications.

ARS chemists Kyung Myung and John Manthey and microbiologist Jan Narciso at the ARS Citrus and Subtropical Products Laboratory in Winter Haven, Fla., began the study using a fungus—Aspergillus niger—to bind and break down FCs in grapefruit juice.

Grapefruit juice contains three main FCs. Myung found that A. niger either bound these FCs or enzymatically broke them down into other products. Enzymatic inactivation of these compounds may be a means of eliminating them from commercial grapefruit juice, and work to identify these enzymes in A. niger is in progress. A. niger is one of the most common species of the genus Aspergillus that can cause black mold on certain fruits and vegetables but often doesn’t cause human disease.

Myung and his team decided to also test edible fungi, or mushrooms. In studies, they found that edible mushrooms such as morels, oyster and button mushrooms—when dried, pulverized and added to grapefruit juice—also removed FCs. That provides researchers with evidence that fungal proteins could be responsible for removing the FCs from the grapefruit juice.

This research was published in the Journal of Applied Microbiology and Biotechnology and the Journal of Agricultural and Food Chemistry.

ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture.

Read the magazine story to find out more.

Current atmospheric ozone levels are already suppressing soybean yields, according to a new study from ARS and cooperators. Photo courtesy of the Department of Energy.

Computer program eases climate change research   Climate change and groundwater recharge   New crop-yield study casts doubt on a climate-change prediction

Scientists Find Ozone Levels Already Affecting Soybean Yields

By Stephanie Yao
November 13, 2009

Current atmospheric ozone levels are already suppressing soybean yields, according to Agricultural Research Service (ARS) scientists and university cooperators studying the effect of global climate change on crops.

ARS plant physiologists Don Ort and Carl Bernacchi, molecular biologist Lisa Ainsworth and geneticist Randall Nelson have been working with University of Illinois scientists on a project called “SoyFACE”—short for Soybean Free Air Concentration Enrichment—to measure how the projected increases in carbon dioxide (CO2) and ozone will affect soybean production. This research supports the U.S. Department of Agriculture priority of responding to climate change.

In their studies, the scientists found that soybean yields increase by about 12 percent at the elevated CO2 levels predicted for the year 2050 (550 parts per million)—only half of what previous studies estimated. They also found that increased ozone is quite harmful to soybean yields, reducing them by about 20 percent.

In addition, current levels of ozone are already suppressing soybean yields by up to 15 percent, according to Ort, who is also research leader of the ARS Photosynthesis Research Unit in Urbana, Ill.

These results led the scientists to examine the combined effects of CO2 and ozone changes on soybeans. They found that elevated CO2 partially offsets the ozone damage, confirming general results obtained with open-top chamber studies conducted at other ARS laboratories.

The ability of SoyFACE technology to test effects of CO2 and ozone in the open air, without the environmental modifications caused by the chambers themselves, means greater confidence in understanding how plants respond in the real world, including the actual estimates of impact on crop yields, according to Ort. FACE technology was first used for crop research by ARS scientists in Maricopa, Ariz., and cooperators.

There is much more to be learned about how other interacting factors that affect ozone uptake may come into play by mid-century. Results from these studies will help breeders develop soybean varieties better adapted to the changing climate.

Read more about this research in the November/December 2009 issue of Agricultural Research magazine.

ARS is USDA’s principal intramural scientific research agency.

A new study by ARS has demonstrated that carefully controlled laboratory tests can accurately detect toxicological risks that might emerge in the field from genetically engineered corn. Photo courtesy of the Department of Energy.

Non-target insects probably affected more by insecticides than by Bt crops   Insect virus could spell doom for potato pest

Predicting the Environmental Effects of Transgenic Bt Crop Lines

By Alfredo Flores
November 12, 2009

Potential risks from new transgenic Bt crop lines can be assessed using carefully controlled laboratory tests, according to findings of a study by Agricultural Research Service (ARS) scientists and cooperators. This finding will help streamline the assessment process for introducing new insect control technology to the marketplace, while ensuring environmental safety.

Bt (Bacillus thuringiensis) is a biological control bacterium that is effective against a number of key insect crop pests. Crops that contain Bt genes have a built-in defense against these insects, but such crops need to be studied to make sure they don’t pose a risk to non-target organisms.

To test whether the impact of these transgenic crops in the field was predictable from laboratory experiments, scientists from ARS collaborated with researchers at Santa Clara University in California to compare all current laboratory and field studies on non-target effects using meta-analyses. Findings of the ARS study suggest that researchers should be able to more accurately predict from laboratory studies the impact that new experimental lines may have in the field.

Entomologists Jian Duan, Jonathan Lundgren and Steven Naranjo led the study. Duan works at the ARS Beneficial Insects Introduction Research Unit in Newark, Del. Lundgren is based at the ARS North Central Agricultural Research Laboratory in Brookings, S.D. Naranjo is the research leader of the ARS Pest Management and Biological Control Research Unit in Maricopa, Ariz.

The study was initiated to test the underlying assumption of biotechnology risk assessment—that laboratory tests can accurately identify potential risks of transgenic insecticidal Bt crops in the field.. The new ARS study demonstrated that carefully controlled laboratory tests can accurately detect toxicological risks that might emerge in the field, thereby reducing the need for more expensive and time-consuming tests.

The study, completed earlier this year, was published in the journal Biology Letters.

ARS is the primary intramural scientific research agency of the U.S. Department of Agriculture.