Grain Moisture Measurements May Divert Mold, Insect Infestation

Grain storage bins are routinely monitored for temperature to control insect and mold problems. Now an Agricultural Research Service (ARS) scientist and his colleagues at Kansas State University (KSU) have preliminary research findings showing that monitoring carbon dioxide--along with humidity and temperature--also may help detect problems more effectively.

Grain moisture content and temperature are the primary factors affecting grain deterioration in storage. If these factors are not properly monitored and controlled, grain quality can deteriorate quickly due to mold growth and insect infestation.

ARS engineer Paul Armstrong at the agency's Grain and Marketing and Production Research Center in Manhattan, Kan., and Haidee Gonzales and Ronaldo Maghirang at KSU monitored a simulated grain storage bin during aeration to determine if high-moisture grain, or adverse storage conditions, in the bin top could be detected using sensors to measure relative humidity, temperature and carbon dioxide levels.

Relative humidity and temperature can be used to estimate grain moisture, while carbon dioxide levels indicate the amount of respiration due, primarily, to molds. Current technology allows relative humidity and temperature sensors to be placed at multiple points within the grain mass. Carbon dioxide sensing is more feasible at an aeration duct.

In the study, sensors were placed at different depths in the bin. High-moisture grain-- comprising about 11 percent of the volume--was placed at the top of the bin and produced high amounts of carbon dioxide, which in most cases was easily detectable during aeration.

Lowering grain temperature with aeration diminished the amount of carbon dioxide produced, making it more difficult to detect unless the carbon dioxide sensor was located very close to the wet grain.

Relative humidity and temperature sensing gave good estimates of grain moisture for all conditions, but under some grain conditions, high carbon dioxide levels persisted for grain considered to be at safe moisture and temperature conditions. Combining relative humidity, temperature and carbon dioxide measurements gave reasonably accurate measurements of grain moisture content as well as overall storage conditions.

ARS is the U.S. Department of Agriculture's scientific research agency.

ARS Scientists Test MRI Device to Measure Body Fat in Piglets

A new magnetic resonance imaging (MRI)-based device--more advanced than the technology used today for body composition tests--can accurately and precisely measure total body fat in piglets using the principles of quantitative magnetic resonance (QMR), according to Agricultural Research Service (ARS) scientists who evaluated the new technology.

The new device, called EchoMRI, was tested by ARS researchers to measure not only total body fat, but lean tissue mass, free water mass and total body water in piglets. The research was done under a grant from the National Institutes of Health, which wants to know if the new technology could have future applications for human pediatric use.

Standard MRI systems are commonly used to scan and visualize tissue in humans. However, when used for body composition analysis, imaging systems are subject to substantial error rates caused by the interpretation of visual images using software that relies on population averages.

EchoMRI uses a new type of QMR methodology to obtain body composition results. Its measurement principle depends on the density of hydrogen nuclei and the physical state of the tissue.

ARS animal scientist Alva Mitchell at the Animal Biosciences and Biotechnology Laboratory in Beltsville, Md., tested the device, developed by Echo Medical Systems, to determine EchoMRI's precision and accuracy in piglets as compared to dual x-ray (DXA) technology and chemical analysis.

Twenty-five piglets, each weighing between 3.5 pounds and 8 pounds, were screened live, anesthetized, and post-mortem, using a prototype EchoMRI device for infants. The piglets were also scanned using DXA and then subjected to chemical analysis.

After DXA scans, EchoMRI screenings, and chemical analyses were completed, EchoMRI was found to be a precise and accurate method suitable for measuring piglet whole body composition, total body fat, lean tissue mass, free water mass, and total body water. While these studies were conducted on piglets, EchoMRI may be transferable to market-weight pigs.

EchoMRI allows for measurements to be conducted in only a few minutes without anesthesia or sedation, is radiation-free, and does not require the subject to remain completely motionless. This facilitates convenient, low-stress repeated tracking of small changes in body composition and can be advantageous to researchers to optimize feed utilization. It could also help researchers identify high-value hogs for breeding.

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

“Fingerprinting” Helps Make Great Grapes

At about this time next year, nearly all of the 2,800 wild, rare and domesticated grapes in a unique northern California genebank will have had their "genetic profile" or “fingerprint” taken. These fingerprints may help grape breeders pinpoint plants in the collection that have unusual traits--ones that might appeal to shoppers in tomorrow's supermarkets. Other grapes might be ideal for scientists who are doing basic research.

That’s according to Agricultural Research Service (ARS) plant geneticist Mallikarjuna Aradhya. He's heading the grape fingerprinting venture.

The grape collection that Aradhya is fingerprinting encompasses vineyards and screened enclosures, called “screenhouses." It is part of what’s officially known as the ARS National Clonal Germplasm Repository for Tree Fruit and Nut Crops and Grapes, in Davis, Calif.

To glean a distinctive genetic fingerprint of each member of the collection, Aradhya uses pieces of genetic material--or DNA--known as microsatellite markers. Eight markers are all that are needed for a genetic fingerprint of more familiar grapes, like close relatives of those already used for making wine or raisins or for eating out-of-hand.

But the lesser-known ones--wild grapes and some prized types from China, for instance--require twice as many markers for reliable identification. That’s due, in part, to the fact that the taxonomy, or relatedness of one kind of grape to another, is quite jumbled, Aradhya noted.

He has already fingerprinted 1,100 better-known grapes and 300 wild specimens.

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

Hydrogen-Producing Bacteria Provide Clean Energy

A new "green" technology developed cooperatively by scientists with the Agricultural Research Service (ARS) and North Carolina State University (NC State) could lead to production of hydrogen from nitrogen-fixing bacteria.

Renewable sources of energy—such as hydrogen—that don't produce pollutants or greenhouse gases are needed to solve global energy shortages. Fossil fuels such as coal, oil and natural gas are nonrenewable energy sources implicated in global warming.

The invention holds promise as a source of hydrogen for use in fuel cell technology. Fuel cell devices combine hydrogen and oxygen to produce electricity and water, and are considered efficient, quiet and pollution-free. Fuel cells are now being tested in a range of products, including automobiles that release no emissions other than water vapor.

ARS inventors Paul Bishop and Telisa Loveless and NC State inventors Jonathan Olson and José Bruno-Bárcena developed the patent-pending technology.

Nitrogen-fixing bacteria play a key role in agriculture. They live in soil and on certain plant roots, and convert nitrogen from the air into a chemical form that plants can use to grow. The researchers developed a way to identify strains of these bacteria that produce hydrogen gas.

Bishop first demonstrated novel aspects of bacterial nitrogen-fixing more than two decades ago. Building on that work, the team developed a method that uses a selecting agent to identify these special hydrogen-producing strains. The selecting agent allows researchers to identify these bacterial strains without the need for genomic sequencing or genetic modification.

Using the selecting agent, the inventors identified a gene that inactivates the bacteria's hydrogen uptake system so that all of the hydrogen produced is released. Because the bacterial cells cannot recycle the hydrogen, the hydrogen they produce can be captured and used as a fuel whose byproduct is water and heat.

Licensing information can be obtained by contacting the ARS Office of Technology Transfer or the Office of Technology Transfer at NC State.

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

Scientists Tie Chickpea Disease to Fungal Culprit

The fungus Sclerotinia trifoliorum plagues legume crops worldwide. But chickpeas seem to have escaped its wrath, with the exception of Australia's crop. Now, that's no longer the case, report Agricultural Research Service (ARS) and collaborative university scientists.

During the 2005-06 chickpea growing season in central California, the team observed stem and crown rots reminiscent of Sclerotinia infection. But subtle irregularities in the symptoms led the researchers to believe their prime suspect—S. sclerotiorum, which infects more 400 plant species—had an accomplice, namely S. trifoliorum.

ARS research plant pathologist Weidong Chen led the team, which included Fred Muehlbauer (now retired) with the ARS Grain Legume Genetics Physiology Research Unit in Pullman, Wash., and University of California-Davis and Washington State University researchers.

They examined 10 Sclerotinia isolates from their collection from chickpea stems and subjected each to three identification criteria: growth rate, ascospore morphology and DNA markers indicative of S. trifoliorum. The team's analysis showed that S. trifoliorum isolates were slower-growing, displayed "ascospore dimorphism," which is the formation of two versions of the same spore type, and harbored a set of group I intron markers while S. sclerotiorum did not.

Chen suspects S. trifoliorum's occurrence on central California chickpeas stems from prior plantings of alfalfa—another legume host—and not an accidental introduction from Australia, the only continent where the fungus has previously been reported on chickpea. Identification of this new chickpea pathogen should aid in improving disease-management practices and developing resistant chickpea cultivars for farmers.

The research is part of the ARS National Sclerotinia Initiative. More information on this initiative is available at:

http://www.whitemoldresearch.com

The research study was published recently in the journal Plant Disease, and is available online at:

http://apsjournals.apsnet.org/doi/interp/10.1094/PDIS-92-6-0917

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

Scientists Tie Chickpea Disease to Fungal Culprit

The fungus Sclerotinia trifoliorum plagues legume crops worldwide. But chickpeas seem to have escaped its wrath, with the exception of Australia's crop. Now, that's no longer the case, report Agricultural Research Service (ARS) and collaborative university scientists.

During the 2005-06 chickpea growing season in central California, the team observed stem and crown rots reminiscent of Sclerotinia infection. But subtle irregularities in the symptoms led the researchers to believe their prime suspect—S. sclerotiorum, which infects more 400 plant species—had an accomplice, namely S. trifoliorum.

ARS research plant pathologist Weidong Chen led the team, which included Fred Muehlbauer (now retired) with the ARS Grain Legume Genetics Physiology Research Unit in Pullman, Wash., and University of California-Davis and Washington State University researchers.

They examined 10 Sclerotinia isolates from their collection from chickpea stems and subjected each to three identification criteria: growth rate, ascospore morphology and DNA markers indicative of S. trifoliorum. The team's analysis showed that S. trifoliorum isolates were slower-growing, displayed "ascospore dimorphism," which is the formation of two versions of the same spore type, and harbored a set of group I intron markers while S. sclerotiorum did not.

Chen suspects S. trifoliorum's occurrence on central California chickpeas stems from prior plantings of alfalfa—another legume host—and not an accidental introduction from Australia, the only continent where the fungus has previously been reported on chickpea. Identification of this new chickpea pathogen should aid in improving disease-management practices and developing resistant chickpea cultivars for farmers.

The research is part of the ARS National Sclerotinia Initiative. More information on this initiative is available at:

http://www.whitemoldresearch.com

The research study was published recently in the journal Plant Disease, and is available online at:

http://apsjournals.apsnet.org/doi/interp/10.1094/PDIS-92-6-0917

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

More Strawberries, More Antioxidant Absorption

Agricultural Research Service (ARS) scientists have assessed the human body's capacity for absorbing certain antioxidant compounds in strawberries, and have found that the absorption of one key beneficial plant chemical was not "maxed out" as volunteers ate more of this popular fruit. Foods high in antioxidants may be excellent sources of healthful compounds, and researchers are striving to learn more about their ability to be absorbed and utilized within the human body.

The study was conducted at the ARS Beltsville Human Nutrition Research Center (BHNRC) in Beltsville, Md., where scientists have pioneered methods for identifying and measuring various plant compounds in fruits and vegetables. Physiologist Janet Novotny, with the BHNRC's Food Components and Health Laboratory, led the study, which was published recently in the Journal of Nutrition.

Marketed year-round, strawberries are the fifth most consumed fresh fruit in the United States, and consumption more than doubled in the past decade, according to experts. Strawberry's antioxidants come in the form of both long-established vitamins and newly defined plant chemicals. Berries are particularly well endowed with a series of compounds called anthocyanins--the source of the berries' blue, purple and red pigments.

In the study, 12 volunteers consumed three different serving sizes of strawberries during three separate treatment periods. Each two-day meal treatment included either 3.5 ounces, 7 ounces, or 14 ounces of blended strawberries, along with a full diet of carefully controlled foods. Each treatment period was separated by a one-week break.

The study showed that the human body is capable of assimilating more anthocyanin pigments as intakes increase. The results will help nutrition scientists evaluate the healthful properties of individual anthocyanins and aid plant breeders in developing varieties with optimal anthocyanin content.

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

Sweet Potato Out-Yields Corn in Ethanol Production Study

In experiments, sweet potatoes grown in Maryland and Alabama yielded two to three times as much carbohydrate for fuel ethanol production as field corn grown in those states, Agricultural Research Service (ARS) scientists report. The same was true of tropical cassava in Alabama.

The sweet potato carbohydrate yields approached the lower limits of those produced by sugarcane, the highest-yielding ethanol crop. Another advantage for sweet potatoes and cassava is that they require much less fertilizer and pesticide than corn.

Lew Ziska, a plant physiologist at the ARS Crop Systems and Global Change Laboratory in Beltsville, Md., and colleagues at Beltsville and at the ARS National Soil Dynamics Laboratory in Auburn, Ala., performed the study. The research is unique in comparing the root crops to corn, and in growing all three crops simultaneously in two different regions of the country.

The tests of corn, cassava and sweet potato were in the field at Beltsville, and in large soil bins at Auburn.

For the sweet potatoes, carbohydrate production was 4.2 tons an acre in Alabama and 5.7 tons an acre in Maryland. Carbohydrate production for cassava in Alabama was 4.4 tons an acre, compared to 1.2 tons an acre in Maryland. For corn, carbohydrate production was 1.5 tons an acre in Alabama and 2.5 tons an acre in Maryland.

The disadvantages to cassava and sweet potato are higher start-up costs, particularly because of increased labor at planting and harvesting times. If economical harvesting and processing techniques could be developed, the data suggests that sweet potato in Maryland and sweet potato and cassava in Alabama have greater potential than corn as ethanol sources.

Further studies are needed to get data on inputs of fertilizer, water, pesticides and estimates of energy efficiency. Overall, the data indicate it would be worthwhile to start pilot programs to study growing cassava and sweet potato for ethanol, especially on marginal lands.

The additional research could help develop new biofuel sources without diverting field corn supplies from food and feed use to fuel.

ARS is a scientific research agency within the U.S. Department of Agriculture.