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Prairie Grains is the official publication of the Minnesota Association of Wheat Growers, North Dakota Grain Growers Association, South Dakota Wheat, Inc. and the Minnesota Barley Growers Assocation. |
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An Update on the Flight against Fusarium Head Blight at the University of Minnesota University of Minnesota 2000 Scab Research Update What has resulted since is an integrated, systematic focus on a specific research objective. Thanks to the sustained funding commitment by the state of Minnesota, the U of M Scab Initiative has resulted in a number of structural and programmatic accomplishments over the past five years. Structural accomplishments include a working coalition between small grain producers and the U of M, stronger linkages with crop scientists regionally and nationally to focus on scab research, and increased public awareness of the community-wide impacts of agricultural disasters. The Initiative has resulted in better greenhouse and field research techniques, so that plant breeding material and pest management protocols can be tested no matter what the weather conditions. The Initiative has also resulted in a more rapid and accurate means of measuring microtoxin levels in grain samples. Programmatic accomplishments over the past five years include new wheat and barley varieties with improved scab tolerance, to be followed by even better varieties several years down the road. The Initiative has also resulted in the discovery of sources and different types of scab resistance in exotic and domestic gene pools, and a better understanding of management techniques. This includes chemical and biological control products and application techniques, as well as a better understanding of the impacts of tillage, previous crop, row spacing, companion crops, and other crop management approaches as a means of minimizing the susceptibility of wheat and barley to scab. Still, small grains producer and research leaders say that despite the considerable research progress, scab remains a threat to small grains production in Minnesota, and a sustained research effort is needed to overcome the disease.
U of M Scab Initiative Accomplishments and Results That checklist has been accomplished under five years of sustained research by the U of M Scab Initiative. Basic knowledge of the fungal disease and methods of researching it have improved substantially. More scab-tolerant wheat and barley varieties have been released as intermediate management tools, with better varieties on the way. New or more advanced research objectives and priorities are being established as initial ones are met. Some of the accomplishments of the U of M Scab Initiative over the past five years: • Creation of scab screening nurseries in Crookston and Morris, and
Development of scab-tolerant barley varieties: Don Rasmusson (left) and Kevin Smith, barley breeders at the University of Rasmusson and Smith have also evaluated 7 second or third cycle breeding populations that involve crosses between a selected scab-resistant progeny from a first or second cycle breeding population and an elite Minnesota breeding line. Progeny from these crosses are more likely to produce an acceptable variety. They have also evaluated 21 lines from advanced cycles of scab resistance breeding in yield trials last summer to assess their agronomic and malting quality properties, with evaluation of the advanced material to continue. "We're still searching for something that has an increased level of resistance, and that gets the DON level to an acceptable level," says Rasmusson. The malting and brewing industry prefers malting barley with DON levels at less than 2 parts per million. In the last year, a new technician has joined the U of M barley breeding program to evaluate and use DNA marker technology to enhance the program's effort to improve scab resistance.
Development of scab-tolerant wheat varieties: Crossbreeding wheat lines to achieve that mix of traits desirable in a new variety is difficult enough, let alone identify genes in the lines that make a cross worthwhile. It's a tall order—like searching for a needle in a haystack. Anderson's breeding program is using DNA markers to help identify genes in wheat responsible for scab tolerance. Just in the last year, Anderson's program identified an additional marker that helps explain how varieties differ in their degree of scab tolerance. Molecular markers are an accurate means of "fingerprinting" germplasm, enabling Anderson to follow traits or genetic makeup in the course of his wheat breeding efforts. Then, based on the pattern revealed by these markers, crosses are selected for better scab tolerance. Anderson's wheat breeding program has 142 lines in advanced yield trials and approximately 450 lines in preliminary yield trials that have been screened in inoculated, misted scab screening nurseries.
FHB Resistance in Wheat and Barley: Effective Screening Nurseries New varieties and potential releases of both wheat and barley are screened for their level of resistance to scab at the Northern Scab Nursery, under The U of M's field screening efforts have expanded the last few years: For example, in 1999 about 800 to 900 barley lines were evaluated in field nurseries at Crookston, the West Central Research and Outreach Center in Morris, and at the Experiment Station in St. Paul. This year, close to 2000 barley lines will be screened. Screening wheat and barley lines for scab tolerance can be challenging, since multiple environments (test locations, years, disease severities) are needed to confirm that truly superior genotypes have been identified. Still, U of M crop scientists have improved screening methods to a point where they are much more confident in the test results. U of M plant pathologist, Ruth Dill-Macky, leads the overall screening efforts. Different levels of disease pressure are created using various amounts of infected corn seed inoculum and a controlled misting system. If varieties are grown under a wide range of disease conditions, the more favorable varieties will exhibit resistance to scab across that range.
Residue Management and Inoculum Potential of Fusarium U of M Soil Scientist Albert Sims, plant pathologist Ruth Dill-Macky, and other crop scientists at the U of M are studying how scab inoculum survives on plant residue, particularly straw and small grains head tissues. The residue composition study, which began in October, 1997, clearly shows that Fusarium can survive on plant residue until flowering of a small grain crop the next year. Researchers continue to evaluate results of the study to make more advanced conclusions. Also in the works: A study on how burning of residue from small grains crops may affect the survival and inoculum production capacity of scab. The study, to be conducted on large plots situated in commercial fields in the Red River Valley, will get underway this year.
Biology, Epidemiology, and Management of Scab Biology and epidemiology studies search for answers on what increases or decreases the potential for scab development, mechanisms of plant resistance, and how environment affects disease development. Included in the research on management strategies is an evaluation of fungicide performance over multiple locations and states. The fungicide evaluation at the U of M is coordinated by Extension Plant Pathologist Roger Jones. Over the last several years, plant pathologists Ruth Dill-Macky, Kent Evans, Charles Hu, and others at the Uof M have improved the University's ability to generate inoculum of the scab fungus Fusarium graminearum for use in greenhouse and field testing, and to inoculate plants uniformly. They have been able to increase the volume of wheat and barley lines being screened (from about 1,000 to 6,000), and made progress in screening material that combines desirable resistance and agronomic traits. Greenhouse testing of wheat and barley lines is conducted three times annually at the U of M: Spring, summer, and winter. From 1994 to 1999, about 10,000 wheat genotypes (70,000 plants) including 100 Chinese wheat varieties have been inoculated and evaluated in the greenhouse at St. Paul.
About the U of M Scab Research Initiative This research partnership has resulted in what may be the largest and most comprehensive effort among agricultural experiment stations in the nation. The U of M Scab Research Initiative involves about 20 principle investigators and in all, about 75 people in four departments and three campuses (St. Paul, Crookston, Morris).
Molecular Approaches of Genetic Resistance to FHB in Wheat and Barley 1) Mapping scab resistance genes in barley—Mapping involves using molecular markers to identify regions of the barley genome that confer with scab resistance. Molecular markers are used to indicate the location of the genomic regions that carry scab resistance genes. Ultimately, the mapping will enable moving genomic regions of barley lines containing scab resistance genes to other barley germplasm adapted for production in Minnesota. 2) Defensive plant response—This work identifies genes in wheat that are involved in the plant's defense response, and specific tissues in the wheat head where infection occurs. U of M molecular scientists are comparing the response to Fusarium graminear-um in the resistant Chinese wheat called Sumai3, compared to the Wheaton variety, which is susceptible to scab. This information will help the researchers determine what types of genes are involved in resistance, or are turned on at a higher level or sooner than others. A better understanding of the infection process and what the plant does to combat infection may make it easier to develop scab-tolerant wheat plants. 3) Gene discovery—This objective is to identify antifungal genes from wheat, barley or any other organism, and isolate genes involved with degrading or detoxifying deoxynivalenol (DON). 4) Transformation—Antifungal protein genes that have been identified from previous studies and from the gene discovery aspect of the U of M's molecular research program are inserted into wheat and barley lines. The U of M has successfully developed transgenic wheat and barley plants, which carry antifungal protein genes that degrade cell walls and membranes of Fusarium. U of M researchers are now testing these transgenic plants to confirm that they will confer an enhanced level of resistance to scab, as intended. Confirming transformation success can be expensive and timely, with a cost estimated at over $75,000 and a process that can take at least 16 months. Thus, one objective of the Minnesota Scab Initiative is to develop a rapid "pre-test" of antifungal genes in engineering better scab tolerance in wheat and barley lines. U of M plant pathologist Richard Zeyen is the leader of a project designed to directly determine the efficacy of antifungal genes in preventing or retarding the growth of scab, subsequently streamlining the transformation process.
Mycotoxin Detection and Analysis The mycotoxin laboratory in the U of M's Department of Plant Pathology provides quick and reliable mycotoxin analysis to all research laboratories involved in the U of M scab research project. Dr. Weiping Xie, lab leader, says accuracy and speed are two key factors in mycotoxin analysis, which is deoxynivalenol (DON, or vomitoxin) in wheat and barley samples. Xie's lab has been able to increase the number of samples it evaluates from about 30 samples a day a few years ago to about 100 today. The lab collaborates with about a dozen other laboratories in the Midwest to cross-check sampling accuracy.
Coordination and Outreach
Pfleger serves as University liaison, working with Initiative researchers and leaders of the Minnesota Wheat and Barley Councils to keep research programs moving forward and to plan and disseminate scab research information to Initiative researchers as well as the public. Small Grains Specialist Jochum Wiersma (no relation to NROC crop scientist John Wiersma) plays a key role in the effort to educate pro
Federal Research at CDL Complements State Effort To that end, the U.S. Department of Agriculture's Cereal Disease Lab located at the U of M's St. Paul campus complements scab research conducted under the Minnesota Scab Initiative. The CDL still focuses much of its attention on rust research, including the monitoring of rust infections in small grains across the nation. However, about one-third of the CDL's research efforts now are focused on scab. Including research by Bill Bushnell, conducted cooperatively with Ron Skadsen, USDA-ARS Barley and Malt Lab, Madison, Wis. Their research has resulted in a method that greatly improves the ability to trace development of the scab fungus in infected head tissues, and ultimately, will help determine the principal pathways of infection in head tissues of wheat and barley. Corby Kistler, CDL research geneticist, is studying genetic variations of the scab pathogen nationwide, which will lead to a better understanding of how Fusarium may infect a wheat field in Minnesota as opposed to a wheat field in Michigan or Arkansas, for example. Kistler also plans to include scab sampling as a new component to the national rust survey conducted annually by the CDL. In all, about four crop scientists at the CDL devote at least a portion of their research to scab, according to Kurt Leonard, who heads the CDL. An additional researcher will join the CDL this year to further boost research efforts there. More information about CDL research may be found on the web: www.cdl.umn.edu Scabby Wheat Assessment Using Machine Vision and Neural Networks
A useable system has been developed, but the machine-method of estimating scab damage is being refined to evaluate most varieties. The technology may also have applications in identity-preserved grain sampling for end-use markets.
Fusarium Head Blight (Scab) Research Initiative Breakdown of Major Projects, Funding, Principle Contacts Development Of Disease-Resistant Wheat Varieties Bob Busch, wheat breeder, ph. 612-625-1975, email: busch005@maroon. tc.umn.edu Development of Disease-Resistant Barley Varieties Kevin Smith, ph. 612-624-1211, email: Molecular Approaches of Genetic Resistance to FHB in Wheat and Barley Biology, Epidemiology, and Management of Scab Mycotoxin Detection and Analysis FHB Resistance in Spring Wheat and Barley: Effective Screening Nurseries Residue Management and Inoculum Potential of Fusarium Support Small Grains Plant Pathologist Positions, Crookston Investigate Pathways of Head Invasions by F. Graminearum Pretesting of Antifungal Genes for Use in Genetic Engineering of Wheat and Barley Scab Research at West Central Research and Outreach Center, Morris Scabby Wheat Assessment Using Machine Vision and Neural Networks Coordination and Communication Contact: Frank Pfleger, ph. 612-625-9736; email: francisp@puccini.crl. umn.edu TOTAL: $1.65 million For more complete research project information or budget details, contact FHB Coordinator Frank Pfleger, ph. 612-625-9736; email: francisp @puccini.crl. umn.edu
Other Contacts: Kurt Leonard, USDA Cereal Disease Lab, ph. 612-625-5786, email: kurtl@ puccini.crl.umn.edu Jochum Wiersma, U of M Small Grains Specialist, ph. 218-281-8629, email: wiers002@maroon.tc.umn.edu Phil Larsen, Vice President & Dean COAFES, ph. 612-625-1999, email: phill@puccini.crl.umn.edu Tom Anderson, Chair, Small Grain Research and Education Committee, ph. 218-354-7556, email: farmandy1@aol.com Marvin Zutz, Executive Director, Minnesota Barley Research and Promotion Council, ph. 218-253-4311, email: mzutz@gvtel.com David Torgerson, Executive Director, Minnesota Wheat Research and Promotion Council, ph. 218-253-4311, email: torgerso@gvtel.com
For More Information.... More comprehensive scab research information may be found in the booklet, "1999 Wheat Research Review." It is free to the public and may be requested by contacting the Minnesota Wheat Research and Promotion Council, 1-800-242-6118. More scab research information is also available on the World Wide Web, at the MWRPC web site, www.smallgrains.org, and the University of Minnesota Agricultural Experiment Station, www.maes.umn.edu. Research conducted at the U of M and other research institutions under the U.S. Wheat and Barley Scab Initiative can be found on the Internet at: www.scabusa.org. This report prepared cooperatively by the University of Minnesota and the Minnesota Wheat Research and Promotion Council. |
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Minnesota, have evaluated seven new sources of resistance in barley
that are parents of populations that will be grown in scab nurseries this summer. They have expanded their greenhouse screening efforts and have evaluated five first-cycle
breeding populations in replicated field trials. These populations are derived from crosses between a new source of resistance to the program and an eliteMinnesota breeding line.
Bob Busch (left), who has been a USDA-ARS wheat geneticist and U of M wheat breeder
since 1978, will retire in June 2000. Jim Anderson assumed the reins of the U of M's wheat breeding program last summer.
the direction of John Wiersma at the Northwest Research and Outreach Center, Crookston, MN. Advanced lines from breeding programs in
the Dakotas, Minnesota, and Manitoba are evaluated each year in this nursery. Most of the lines are being evaluated in other FHB nurseries as well, to gauge scab tolerance in different
geographic areas. Decisions regarding release of new varieties are made after reviewing results from several nurseries and years.
Molecular geneticist Gary Muehlbauer oversees transgenic efforts at the U of M to identify and
insert genes in wheat and barley that convey increased levels of resistance to scab and Don.
Frank Pfleger, professor and head of the U of M
Department of Plant Pathology, serves as coordinator of the Minnesota Scab Initiative. He replaced Gary Lemme, former head of the West Central Research and Outreach Center in Morris, who accepted a position
with the Michigan Agricultural Experiment Station last fall.
ducers about Minnesota Scab Initiative research results. Based at the NROC since 1995, Wiersma works with county extension educators to develop educational programs as
well as address timely small grains-related production issues. He also conducts research and on-farm trials as demonstration and evaluation tools in western Minnesota.
Roger Ruan and other researchers at the U of M Department of Biosystems and Ag Engineering
are developing a machine that will replace human eyes to determine the level of visual scabby kernels in wheat.