NSRL Bulletin Oct. 1999

Using samples from a new statewide testing program, scientists at the University of Illinois have launched an ambitious program aimed at better analyzing the distribution of various races of soybean cyst nematode (SCN) in the state.

"We are running race tests on samples that have come in for soil tests from the SCN Coalition and from samples submitted to the U of I Plant Clinic for diagnosis," says Greg Noel, nematologist, with the USDA Crop Protection Unit at the U of I. "The testing program provides us with unique access to samples from a wide part of the state. Eventually, we hope to run three to four race tests for each county, which will amount to roughly 300 to 400 tests."

The SCN Coalition is a partnership of state soybean boards and land grant universities in ten north-central states, as well as key industry and grower participants. The program originated from funding provided by the North Central Soybean Research Program, an alliance of ten state checkoff boards that finances soybean research projects.

The state testing program represents a cooperative effort among many groups and organizations, including the Illinois Soybean Checkoff Board, the U of I, and the Illinois Soil Testing Association. The Illinois Soybean Association and the Illinois Soybean Checkoff Board are providing financial assistance for educational resources and support for coordinating the many activities of this project.

"The SCN Coalition in Illinois has certainly played a key role by increasing awareness of the problem," Noel says. "That awareness is especially important because there are still growers around the state who know their yields are dropping yet have not taken a soil sample for testing."

He notes that his initial tests have focused on samples gathered from the central and northern parts of the state. Preliminary results from limited available data indicate that most of the samples show infestation by Race 3, with a few others from Race 1 and a single sample from Race 6.

"Those numbers basically correspond to data that we published in 1990," Noel says. "In that study, we tested about 50 samples from different counties. About 65 percent of the samples in that case were Race 3 and about 30 percent were Race 1. There were only a few samples of Race 2, Race 4, and Race 5."

He adds, however, that the single population of Race 6 identified in the new tests marks the first time that race has been found in Illinois.

"Nevertheless, it appears that the situation has not changed much because of the wide use of resistant varieties," Noel says. "I know that some of the samples from the SCN Coalition have come from fields where growers have planted resistant varieties and apparently there has not been a big shift in the race composition in the state as a result."

According to Noel, the lack of a major race shift indicates that many growers are doing the necessary things to control nematodes in their fields.

"The results tell me that the nematode populations in many fields are being reduced to low levels and that there is not a high level of selection pressure being exerted against the soybean varieties that are being planted," he says. "The danger for growers comes when they have a high level of nematodes and then plant a resistant variety without first knocking that population down by planting a non-host such as corn or by planting a resistant variety year after year."

He emphasizes that the information from the race testing program will be especially valuable for soybean breeding programs that focus on developing resistance to SCN.

"The results can provide a good indication of where we need to focus our efforts and what types of resistance we should be working on," he says. "I also have been advocating for a long time that growers need to know what varieties to plant to combat the particular race in their individual fields."

According to Noel, obtaining accurate data on the distribution of races has become even more important as the result of recent research at the U of I, which confirmed that rotating soybean varieties with different sources of resistance can reduce cyst nematodes in a field to undetectable levels.

"Once cyst nematode is introduced into a soybean field, infestations may build up and damage can appear within a few years when varieties with the same source of resistance are repeatedly planted," Noel says "The problem can be slowed down somewhat but not prevented by using a corn-soybean rotation. By rotating soybean varieties with different sources of resistance, however, we found that nematode levels can be reduced to almost zero in those same fields."

In this 11-year study, which was carried out in collaboration with Dale Edwards from the U of I’s Department of Crop Sciences, cysts from a natural infestation in a producer’s field were added to the plots to mimic what occurs during preparation for planting and during cultivation. The infested plots were then planted with soybeans using the "Peking" source of resistance.

"By the fourth and fifth years, the plots began to show a marked increase in nematode populations," Noel says. "At that point, we changed to the variety Fayette, which has a different source of resistance. We carefully measured the number of cysts in the soil each year. After five years of planting Fayette, the cyst nematode populations were reduced to non-detectable levels even in the fields that were not rotated with corn."

Noel notes, however, that the strategy will only work when the genes for virulence against the rotated source of resistance do not occur in the races present in a field.

"This means that it is important for producers to know exactly what races of cyst nematode are present in their fields," he says. "A mere guess is not good enough. If a producer makes a bad guess and plants the wrong sources of resistance, there will be as much of a problem as if a susceptible variety was planted."

Research carried out in collaboration with U of I soybean breeder Cecil Nickell has resulted in the release of five varieties and germplasm lines that are resistant to races that attack both "Peking" and Fayette.

"In addition, the North Central Soybean Research program recently funded a new multi-state project in which we are studying rotation of those soybean lines and how they affect cyst nematodes," Noel says.

He adds that one drawback to rotating sources of resistance is that there has not been an adequate testing program for growers to determine the races in their fields. Current tests occupy a large amount of greenhouse space and are time consuming.

"Recently we have been working to develop a quicker molecular assay for determining races, which could change the situation in the future," Noel says. "New work on this technique is now underway thanks to support from the Illinois Council on Food and Agriculture Research (C-FAR). The real payoff will come when we can use this new testing procedure to more easily determine the proper rotation of resistant varieties on individual fields."

As the result of efforts by the International Soybean Program (INTSOY) at the University of Illinois, entrepreneurs in such far-flung countries as Bangladesh and Bulgaria have recently developed a new appreciation for one of America’s most important crops--the soybean.

"For years, we have been training private business people from around the world how to process and use soybeans," says INTSOY Director Karl Weingartner. "Bangladesh and Bulgaria are just two of many examples where all that hard work is really beginning to pay off for U.S. producers, processors, and equipment manufacturers."

He notes that INTSOY’s most important mission in the last 25 years has been to assist the private sectors in developing countries to process and use soybeans. With support from the U.S. Agency for International Development, this program in the U of I’s Department of Food Science and Human Nutrition has established itself as an international center of excellence for soybean processing and utilization technologies.

Over the years, more than 200 people from 41 different countries have attended the annual month-long training course held at the U of I’s National Soybean Research Laboratory. Another 230 students from 33 different countries have participated in customized, short-term training programs. In addition, some 300 people from 22 different countries have participated in workshops conducted overseas.

"As a direct result of these programs, participants have opened their own businesses, developed and marketed new products, and initiated government programs for soybean utilization in their home countries," Weingartner says. "In recent years, the course has attracted many entrepreneurs who have developed lasting business relationships with U.S. food and agriculture companies."

He cites the example of an entrepreneur from Bulgaria who met with representatives from a number of U.S. agribusinesses as part of the course. After returning home, he maintained contact with INTSOY and several of the U.S. companies.

"In 1998, he formed a partnership with two other Bulgarians to remodel a former agricultural cooperative into a soybean processing plant," Weingartner says. "The factory, which recently opened, is using U.S.-made equipment to process soybeans into meal for poultry feed. In addition, they are selling their excess meal to nearby poultry producers. In spite of the problems in their country, these entrepreneurs have been able to steadily increase the production of soybean meal since they first opened."

Weingartner adds that one of the keys to their success was INTSOY’s help in designing an appropriately sized facility that allows them to produce soybean meal in quantities they can readily sell.

In another example, a businessman from Biolink Technologies Ltd. in Bangladesh returned home after attending the INTSOY course with new information that allowed him to develop and market a popular, high-protein biscuit made from soy flour.

"When the government of Bangladesh learned that Biolink Technologies was collaborating with the U of I, it began purchasing the biscuits for use in its disaster relief program," Weingartner says. "As a result of its relationship with INTSOY, the company has experienced rapid growth. It currently employs 60 people and soon plans to open a second factory."

Although those specific projects are relatively modest in scale, a number of larger soy processing ventures based on contacts with INTSOY are underway in countries ranging from Thailand to Egypt.

"One of the major success stories involves a large soymilk company in Thailand," Weingartner says. "One the company’s employees attended our course to learn more about innovative methods for processing soybeans. Since then, the company has modified its processing methods, so as to greatly improve the taste of its soymilk."

According to Weingartner, the most important element in the success of all these efforts has been the cooperation with American agribusinesses.

"In recent years, we have placed special emphasis on the need to link together foreign and domestic businesses with common concerns and interests," he says. "The results have included joint overseas workshops and country training sessions, increased visits from foreign entrepreneurs, and referrals for purchases of supplies and equipment. What we are most proud of is that, in virtually every case, these contacts have proved beneficial for both the domestic and foreign partners in the exchange."

By analyzing the byproducts from soybean processing, a research team at the University of Illinois working in collaboration with scientists from the USDA’s National Center for Agricultural Utilization Research in Peoria has identified a previously overlooked group of compounds known as soybean saponins that display strong anti-mutagenic activity in mammalian cells.

"We focused our research on the commercial byproducts because most people are exposed to the compounds in soybeans in the form of processed food," says Michael Plewa, professor of genetics in the U of I’s Department of Crop Sciences. "We found that there are an enormous number of extremely interesting compounds in the processing waste product known as soy molasses."

Working with Senior Research Specialist Elizabeth Wagner, Plewa initially developed an innovative technique that allowed them to rapidly screen the various compounds in soy molasses for their anti-mutagenic potential in mammalian cells. Support for this research was provided by the soybean checkoff through the United Soybean Board.

"Although there is a lot of work published on the health effects of a soybean diet, very few of the individual compounds in the soybean have been isolated and tested for their chemo-protective activity," Plewa says. "With this new technique, we were able to zero in on some of the most promising chemical fractions. Many of these turned out to be compounds that we knew very little about."

In collaboration with analytical biochemist Mark Berhow of the USDA, the team recently has identified one particularly promising group of anti-mutagenic compounds known as soybean saponins.

"Some of the best anti-mutagens that we found in the soybean molasses byproduct are from this one particular group of compounds," Plewa says. "The specific chemical fraction called soyasapogenol B appeared especially promising. Surprisingly, there has been relatively little work on the biological activity of the saponin compounds. Unlike the isoflavones, they are not available commercially."

He notes that a novel assay technique developed for this project allowed them to rapidly identify individual compounds that have anti-mutagenic activity.

"We also asked whether these compounds could suppress the activity of the major human dietary carcinogen that we all are exposed to when we cook meat," Plewa says. "We found that even low concentrations of soyasapogenol B will suppress this mutagenic activity. So far, we have shown that the saponins can repress some of the activity of the known carcinogens that are responsible for the high rate of colon cancer in the U.S."

After an intensive effort to isolate and chemically identify the most promising chemical fractions, the team began testing the ability of the compounds to repress the growth of cultured human tumor cells in the laboratory.

"To speed up this work, we have developed another semi-automatic assay technique that can rapidly determine if a compound can suppress the activity of a human tumor cell line," Plewa says. "This is important because current chemotherapy treatments would have more time to work if you could slow down the rate of tumor growth."

He notes that the next stage in the research will involve studies to see if these compounds can actually improve the long-term survivability of animals that have tumors.

"Although there is still a lot of work to be done, we clearly have found a treasure trove of promising compounds in the soybean byproducts," Plewa says. "We now are trying to come up with even better ways to screen those products and to pick out the real jewels so that additional work can be done on those compounds."

As a health claim linking soy protein consumption with a reduced risk for coronary heart disease awaits approval with the FDA in Washington, a study at the University of Illinois has determined the optimal dose of soy protein required to lower blood cholesterol in men.

Study participants with cholesterol levels ranging from 220 to 300 milligrams per deciliter (mg/dl) ate five servings a day of flavored muffins, flat breads, and drinks containing isolated soy protein in different amounts for six weeks. A control group consumed products with casein, a milk-based protein.

Study results showed that as little as 20 grams of soy protein per day was effective in lowering cholesterol levels, according to Clare M. Hasler, U of I assistant professor and executive director of the Functional Foods for Health Program. The pending health claim for foods containing soy protein identifies 25 grams per day to produce health effects.

While more than 45 human clinical studies have been conducted on the effects of soy protein, this is the first study to determine how much soy protein should be consumed to lower cholesterol.

"We are very pleased with the results," Hasler says. "We did not anticipate that 20 grams would be effective in lowering cholesterol in just six weeks. The results complement the health claim nicely."

Products that qualify for the pending health claim must contain 6.25 grams of soy protein per serving. To consume 20 grams of protein per day, a person might eat a soy burger containing 18 grams, and a one-half glass of soy milk.

Once the claim is approved, it is likely that the food industry will respond with new products containing soy protein. Even without the claim, the market for soy products has increased 22 percent in the past year, Hasler says. The most popular soy products are tofu and soy milk.

"It is encouraging that we can let people know that there is something else out there that will lower their cholesterol besides oats and psyllium fiber," Hasler says.

During the last 50 years, plant breeding research and improved agronomic practices have produced major increases in soybean yields. But, according to Brian Diers, soybean breeder in the Department of Crop Sciences at the University of Illinois, further yield increases will be essential if soybeans are to remain competitive in the global marketplace during the next century.

"The yield increases over the last few decades have improved the efficiency of soybean production and have helped make soybean the most important oilseed crop in the world," Diers says. "However, future yield increases could be slow because the North American soybean germplasm has a narrow genetic base."

Soybean breeder Brian Diers examines the soybean relative, Glycine soja, in a test plot at the U of I’s Crop Sciences Research and Education Center. Early research results indicate that this wild relative of the soybean could prove to be a valuable source of new genes for eventually improving the yield of the U.S. commercial crop.

He notes that more than 80 percent of the soybean germplasm in North America can be traced to only 10 soybean lines that were brought into the United States at the turn of the century.

"This genetic bottleneck, along with a bottleneck that occurred when soybeans were domesticated, has reduced the number of genes that can be selected when developing new high-yielding cultivars," Diers says. "Genetic diversity is especially important for plant breeders because genes are the raw material they use in developing higher-yielding varieties."

Diers explains that, in order to develop new varieties, breeders cross different soybean lines together and yield-test the resulting experimental lines. Lines that exceed the performance of their parents are released as new varieties.

"In this process, breeders essentially mix up genes from the parents and, through selection, identify the lines with improved combinations of genes," he says. "Because of the limited genetic diversity in soybean, breeders may well be running out of yield genes from which to select in their programs."

With support from the Illinois Soybean Checkoff Board and the U.S. Department of Agriculture, Diers is investigating whether the species Glycine soja, which is the wild ancestor of the soybean, will prove to be a valuable source of new genes for improving the yield of the crop.

"Although the wild soybeans have poor agronomic appearance, it is very likely that they have useful genes that were not brought into soybean during the domestication process," he says. "Similar studies in rice and tomato have resulted in the identification of genes from wild ancestors that have improved yields in those crops."

According to Diers, there is no reason to think the same would not be true with the wild ancestor of the soybean. To study genes from G. soja, he has developed several populations that segregate for different genes from that species.

"Those populations are currently being evaluated through yield test in the field and with genetic markers in the laboratory to determine if there are useful genes in the wild relative of the soybean," he says.

In another project, Diers is using similar genetic markers to locate new sources of genes that can offer resistance to the soybean cyst nematode (SCN), which is the leading pest of soybeans in the U.S. This effort is funded by the Illinois Soybean Checkoff Board and the United Soybean Board.

"This work is underway because the SCN-resistant varieties of soybeans that are available to growers have mostly the same resistance genes," Diers says. "Dependence on these genes could be dangerous because the nematodes could overcome this resistance, making all varieties susceptible to the pest."

Diers' search for novel resistance genes is centered on plant introductions collected from around the world, which are maintained by the USDA in the soybean germplasm collection at the U of I.

"We are determining, through the use of DNA markers, whether these plant introductions have the same resistance genes as current varieties," Diers says. "Those DNA markers provide landmarks at various regions on the soybean chromosomes that allow us to study genes in those areas."

For the DNA analysis, soybean populations are developed from crosses made between plant introductions and current SCN-resistant varieties, or from crosses between two plant introductions.

Diers is collaborating in this national project with Silvia Cianzio of Iowa State University and Prakash Arelli of the University of Missouri-Columbia. Cianzio developed the soybean populations for the project, which are being evaluated by Arelli for SCN resistance, and by Diers for their DNA makeup.

"We are testing the soybean populations with DNA markers that have been shown to be linked to SCN-resistance genes," says Diers. "This will allow us to determine whether these populations possess the same resistance genes as other populations, or if they have new resistance genes."

As many of you may know, the National Soybean Research Laboratory had the great pleasure of hosting Global Soy Forum 99 from August 4 to 7 this year. Along with our co-host, the Soybean Research Development Council (a joint venture of the Iowa and Illinois Soybean Checkoff Boards), we welcomed over 1800 guests from more than 60 countries to Chicago. With nearly 200 speakers, this diverse and comprehensive program addressed topics relevant to the entire soybean value chain. In the next issue of the NSRL Bulletin, we will bring you a special pictorial review of the many events at Global Soy Forum 99.

In my remarks here, I would like to reflect on one segment of Global Soy Forum 99 that was particularly interesting to me. As part of the plenary session on future directions of the soybean industry, six young people from around the world provided their perspectives on key issues as they embarked upon careers in soybeans. They focused on an incredible array of topics, such as human needs for protein, disease prevention, acceptance of genetically-enhanced soybeans, enhancing the efficiency of animal production, economic development and food processing, and innovations in production technologies.

Their home regions and their professional interests clearly highlighted the diversity of the world soybean community:

As an educator, it was especially gratifying for me to listen to these young people address key issues facing the soybean industry of the future. Although our focus at NSRL is necessarily on research and the benefits that research can bring, we can never forget that attracting the best young people to our industry will be one of the key determinants of our future success.

The NSRL Bulletin is published three times a year by the National Soybean Research Laboratory at the University of Illinois, 170 Environmental and Agricultural Sciences Building, 1101 W. Peabody Drive, Urbana, IL 61801; telephone (217)244-1706; e-mail nsrl@uiuc.edu; FAX (217)244-1707. Steven T. Sonka, director; Robert J. Wynstra, editor; Lisa Sheppard, contributing editor; David Riecks, photographer; Lynn Hawkinson Smith, graphic designer.

Unless otherwise stated, articles may be reproduced or quoted if credit is given to the NSRL Bulletin. The National Soybean Research Laboratory at the University of Illinois is an affirmative action and equal opportunity institution.

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