College of ACES
College News

Soil microbes shift as shrubs invade remnant hill prairies

Published March 11, 2014
Prairie hill remnant

URBANA, Ill. – Perched high on the bluffs of the big river valleys in the Midwest are some of the last remnants of never-farmed prairie grasslands. These patches, edged by forest, are slowly being taken over by shrubs. A recent University of Illinois study examined the soil microbes on nine patches, also called “balds,” that had varying degrees of shrub invasion and found an interesting shift in the composition of the microbial community.

“When we looked at the soil samples from a lightly encroached hill prairie remnant, it was very clear that there was a set of fungi that look like grassland fungi, a set of fungi that look like tree fungi, and the shrubs between the two have some features of both,” said U of I microbial ecologist Tony Yannarell. “As the degree of shrub encroachment increased, the amount of change in the fungal communities also increased, and as the degree of shrub encroachment increased, that shrub fungi joined the forest group to become one big woody community.”

Yannarell said that on the balds that were completely encroached, the soil samples across the entire remnant were the same. “You get this shift toward woody fungal communities that mirror how much shrub density you have in the hill prairie,” he said.

Yannarell said that forest and prairie microbial communities are always very different from each other even in this case where they are only a couple of meters apart. And because of the close proximity, with the same overall climate conditions and soil origin, they could rule out a lot of factors that would normally affect a change in microbial community structure.

The microbes in the shrub soil tend to be different, but different parts of the microbial community change in relationship to the shrub, to the forest, to the prairie. The shrub bacteria are more like what they found in open prairie than in the forest. But the shrub fungi looked a lot more like the forest fungi.

“We think what we found is the signature of these early changes, these early shifts of microbial communities toward a woody fungal community,” Yannarell said. “This first study only reveals one side of the change. We think we can firmly conclude that there are some woody, plant-liking fungi. But we don’t know if they are enhancing the invasion of it. They could be holding it back if there are shrub diseases.

“We’re also interested in knowing if the shrubs have changed these microbes because that could have an effect on a landowner’s ability to restore a heavily encroached hill prairie,” Yannarell said. “If you cut down all of the shrubs, you haven’t changed the microbial communities that live in the soil that the shrubs created. We want to know if those shrubby communities can be invaded by grasses or have they changed something fundamentally so that it will be harder to restore the prairie,” he said.

Yannarell explained that the remnant hill prairies are on portions of the bluffs where the soil is erodible, and because it is facing the sun for more of the year, it’s slightly warmer and slightly drier. More frequent fires would tip the balance toward grassland, but fires have been suppressed for many decades in the area because people live and farm nearby. The hill prairies are shrinking as the forest, and now native shrubs, such as dogwood, sumac, shrubby black locust, and eventually red cedar move in.

“We don’t know yet what kind of long-term impact this could have on the environment,” Yannarell said. “As the environment becomes unfavorable for certain microbes, those microbes will die off,” he said. “The shrubs could be driving out grass-loving fungi in favor of shrub-loving fungi. It’s yet another example of a monoculture taking over.”

Yannarell said that this research will be the foundation for a lot of work they’ll do in the future.

“Influence of Shrub Encroachment on the Soil Microbial Community Composition of Remnant Hill Prairies” was published in the February 2014 issue of Microbial Ecology. Contributing authors were Sarah E. Menning and Alyssa M. Beck.

Funding for this research was provided by the National Great Rivers Research and Educational Center.


NRES Teachers Ranked as Excellent for Fall 2013 Semester

Published March 10, 2014

NRES congratulates the following teachers ranked as Excellent for Fall Semester 2013!

  • Kingsley Allan              454
  • Matthew Carter           TA 454
  • Morgan Davis               TA 201
  • Jody Endres                 426
  • Jennifer Fraterrigo       465
  • Heather Grant             TA 415
  • Tyler Groh                    TA 102
  • *Jeffrey Matthews       285,512
  • Ronald Salemme          TA 201
  • *Cory Suski                 285,409
  • John Taft                     415
  • Anthony Yannarell       219

* -The instructor ratings were outstanding.

TA –teaching assistant

News Source:

Lezli Cline, 244-6254

Calculations for March 1 corn stocks estimate

Published March 10, 2014

URBANA, Ill. – The USDA will release an estimate of March 1, 2014, corn stocks on March 31 with potentially important implications for old-crop corn prices.  According to a University of Illinois agricultural economist, it has been difficult to correctly anticipate quarterly stocks estimates in recent years, with large surprises reflected in some estimates.

“The estimate of Dec. 1, 2013, stocks was surprisingly small and implied a record 2.426 billion bushels of feed and residual use of corn during the first quarter of the 2013-14 marketing year,” said Darrel Good. “That estimate started a price rally that was subsequently augmented by surprisingly large export sales of corn. March 2014 corn futures increased about 70 cents from Jan. 9 through March 7.

“While it has become difficult to anticipate the quarterly stocks estimate, it is useful to calculate the magnitude of stocks that might be considered neutral for corn prices,” Good said. “A large deviation from that calculation would be expected to trigger a price response. A stocks estimate that would be neutral for corn prices is one that implied that feed and residual use of corn during the first half of the marketing year supported the USDA’s forecast of 5.3 billion bushels of feed and residual use for the entire marketing year. Even that calculation is difficult to make, however. The difficulty stems from the change in the seasonal pattern of feed and residual use that has occurred over the past seven years. For the 10 years from 1996-97 through 2005-06, feed and residual use of corn during the first half of the marketing year averaged 64 percent of the marketing-year total use, in a range of 62 to 66 percent. For the four-year period from 2006-07 through 2009-10, use during the first half of the marketing year averaged 68 percent of the total, in a range of 66 to 70 percent. During the three-year period from 2010-11 through 2012-13, use during the first half of the year averaged 74 percent of the marketing-year total, in a range of 73 to 76 percent.”

Good continued, saying that the increase in feed and residual use of corn during the first half of the marketing year and the sharp decline in use during the last half of the year are difficult to explain. Most of the shift has been from the fourth (summer) quarter to the first (fall) quarter. From 1996-97 through 2006-07, first-quarter use ranged from 35 to 39 percent of the marketing-year total, and fourth-quarter use ranged from 11 to 17 percent. From 2007-08 through 2012-13, first-quarter use ranged from 38 to 48 percent, and fourth-quarter use ranged from 6 to 13 percent. For the four most recent years, fourth-quarter use averaged only 8 percent of the marketing-year total and declined to 6 percent in 2012-13.

“Some of the seasonal shift in feed and residual use of corn may be associated with high corn prices and increased feeding of other grains, particularly wheat, during the summer quarter,” Good said. “The shift in some years, particularly 2011-12, may also be associated with early harvest and the resulting shift in calculated feed and residual use from the summer quarter into the fall quarter. If those factors do explain some of the shift, feed and residual use during the fourth quarter of the current marketing year might be larger than in recent years. Corn prices are low relative to other feed ingredients, particularly wheat, and it appears that the 2014 crop will not be planted and harvested particularly early in the Midwest. The percentage of feed and residual use of corn during the first half of the current marketing year might be expected to be smaller than the 74 percent in recent years. The impact of PED-V (Porcine Epidemic Diarrhea Virus) on the number of hogs fed during the last half of the year, however, could also impact the seasonal pattern of corn feeding,” he said.

Good said that if the USDA’s 5.3-billion-bushel projection of feed and residual use of corn for the year is correct, and 70 percent was used during the first half of the year, use during the second quarter of the year would have totaled 1.284 billion bushels. Based on Census Bureau estimates for December 2013 and January 2014 and USDA export inspection estimates through February 2014, corn exports during the quarter were likely near 396 million bushels. Based on estimates of ethanol production during the quarter, corn used for ethanol production was likely near 1.265 billion bushels. Corn used in other domestic food and industrial processing should have been near 340 million bushels, resulting in a total use of 3.285 billion bushels. With Dec. 1 stocks of 10.426 billion bushels and imports during the quarter of about 6 million bushels, these calculations point to March 1 stocks of 7.147 billion bushels.

“Given the large amount of uncertainty about the potential seasonal pattern of feed and residual use of corn, a stocks estimate that varied from the calculation presented here could still support the USDA projection of 5.3 billion bushels of use for the year,” Good said. “The market will have to decide if the magnitude of use during the first half of the year is a reasonable percentage of the USDA projection for the year or if the projection will need to be changed.”

Community & Campus Day of Service April 5th

Published March 10, 2014
Campus Day of Service April 5
Campus Day of Service

The second annual Community & Campus Day of Service will be held on Saturday, April 5 at Memorial Stadium to kick off National Volunteer Week, April 6-12.  During the inaugural event last April, more than 1,500 volunteers came together to participate in a number of service projects, including a food packaging project that eventually provided 146,000 meals to the Eastern Illinois Foodbank.  It is hoped that this year even more volunteers and units will become involved in the Day of Service.  You can get involved either by volunteering for an existing project or by participating in some sort of community service on your own or as a unit during National Volunteer Week. 

Opportunities for volunteering will include:

  • A food packaging project on April 5 with a goal of providing 147,000 meals to Eastern Illinois Foodbank (1,000 meals for each year of the University’s public engagement mission)
  • Service projects throughout Champaign-Urbana as part of Austin's Day on April 12
  • Coming up with a unit volunteer project during National Volunteer Week (last year, Beckman and Fine & Applied Arts both offered projects open to volunteers inside and outside of the unit)
  • Visit for additional volunteer opportunities (individual or group)

Please be sure to report any unit or individual community service, to be included in the total hours spent in the Community & Campus Day of Service total throughout National Volunteer Week.  Remember that the projects are open to anyone in the community, and several are family friendly (children 5 years of age and up can participate in food packaging), so invite others to join you!  More information is available at, including registration and reporting for volunteer projects. 

Thank you for your support of this important annual event!

News Source:

Lezli Cline, 244-6254

Malnourished children are better fed when mothers have network of peers

Published March 10, 2014
Group of women

URBANA, Ill. – Women in rural India who participate in a vocational training program learn more than just life skills. A recent University of Illinois study found that mothers who participated in a program designed to educate and empower women gained a network of peers that led to increased bargaining strength in the home, and significantly improved their children's consumption of rice and dairy.

 “Prior to participating in Mahila Samakhya, which loosely translates to women of equal value, most of the participants reported regularly communicating with fewer than five women outside their families,” said U of I economist Kathy Baylis. “Some of the women initially said things like, ‘I never knew anybody like me could work outside of the home’ and ‘I never knew anyone like me could stand up to her husband.’ But after participating in the program, even if they didn’t go out and use that vocational training in jobs, they felt that they had a little more right to say, ‘No, I think this is how we should be spending our money in our household.’ Women were exerting more of a say over household resources,” she said.

In India, over 40 percent of children under the age of five suffer from malnutrition. This is despite the fact that per capita income has more than doubled since the mid-1990s and agricultural production is at an all-time high, with large buffer stocks of cereals in government granaries.

“There’s evidence that if women have more bargaining power in the household, particularly in developing countries where cash is very tight, quite often more resources go toward the kids,” Baylis said. “So, to test that hypothesis, we went into homes with bowls and asked how many bowls this size of rice did your kids eat yesterday? Not only do we see evidence that more is going to kids, but more food is going to girls in particular, which is good because they tend to be the least powerful persons in the household. When times are tight, the girls’ food is usually what’s cut back,” she said.

In the study, 487 women were surveyed from six of thirteen districts in Uttarakhand, four with the program and two without. Baylis said that the study shows that women who are more empowered, educated, and mobile can actually change the village culture.

“Participants told us that before joining the program they couldn’t work, had little contact outside the family, and had little say in the resources allocated to their children,” Baylis said. “Their identity was always subsumed in their husband's, brother's, father's, or in-laws' identity. But after participating in Mahila Samakhya, women realized they have their own identity, that they can work if they want to, and that they can influence household and community decisions.”

Baylis said that local men sometimes resist the program and prevent their wives from participating.  As a result, initially only a few women may participate, but as others see the benefits, they muster up the courage to participate despite family opposition.

“In this area of India, domestic violence is a huge problem,” Baylis said. “In a couple of the villages, we heard of support groups where women would go knock on doors and threaten to expose men if they didn’t stop the violent behavior. 

Baylis explained that the program is run through a branch of the Indian central government.  A worker talks to people in the villages and gets a sense of where people might be receptive and finds out their interests, for example, if they’d like additional nutritional education or if there are particular job skills they would like to have.

“It’s a very powerful program, but it is also very difficult to analyze because each program looks slightly different in each location. But the idea is the same – to bring together women in the village with some training and set up a support group,” Baylis said.

This study is one of the first to study how peer networks affect female bargaining power and child welfare and one of the first evaluations of the Mahila Samakhya program since it began in 1995. The findings were shared with those who run the program to help them see what’s working and what could be expanded. 

“Expanding Horizons: Can Women’s Support Groups Diversify Peer Networks in Rural India?” co-authored by Eeshani Kandpal, was published in the American Journal of Agricultural Economics.  Funding was provided by the Arnold O. Beckman Award from the U of I Campus Research Board.


2014 All-America Selections Winners

Published March 7, 2014

URBANA, Ill. – All-America Selections is an independent, non-profit organization that tests new varieties then introduces only the best garden performers as AAS Winners., said a University of Illinois.

“The AAS Winners offer gardeners reliable new varieties that have proven their superior garden performance in trial grounds across North America,” said Ron Wolford, a University of Illinois Extension horticulture educator.

For 2014, All-America Selections is recognizing both national and regional winners.

“As you plan your 2014 garden, think about adding some of these 2014 All-America Selections winners,” Wolford said.

Gaura 'Sparkle White': ‘Gaura 'Sparkle White' has long slender stems with a large number of dainty white flowers tinged with a pink blush. It loves full sun and is heat tolerant. ‘Sparkle White’ will bloom from late spring to frost.

Penstemon ‘Arabesque ™ Red’ F1: This hybrid has red and white bicolor large bell-shaped flowers. It does best in full sun. It will attract butterflies and hummingbirds all summer. It will bloom from summer to frost. Penstemon ‘Arabesque™ Red’ F1 is heat tolerant.

Sunflower 'Suntastic' F1: This is a new dwarf sunflower growing 10 to 24 inches tall. It is great for containers. Each plant produces up to 20, 5 to 6-inch flowers per plant in three successive blooming periods. Sunflower 'Suntastic' F1 will bloom in 65 days from seed.

Petunia 'African Sunset' F1: Plants will bloom from late spring to frost with orange flowers. The mounded spreading plants will grow 12 inches tall and spread up to 20 inches. Petunia 'African Sunset' F1 is good for containers or hanging baskets.

Bean 'Mascotte': This is a bush-type bean with long slender pods that stay above the foliage for easy harvest. Bean 'Mascotte' has white showy flowers. The stringless pods are very crisp. It goes from seed to harvest in just 50 days.  Bean 'Mascotte' is great for containers and window boxes.

Cucumber 'Pick a Bushel' F1: This heat-tolerant pickling cucumber can be picked at the gherkin or spear stage. The semi-bush plants can be planted in the garden or in patio containers. Cucumber 'Pick a Bushel' F1 takes 50 days from seed to harvest.

Pepper 'Mama Mia Giallo' F1: This is an early-maturing, yellow, sweet Italian pepper. It produces a huge yield of peppers with a sweet flavor. The peppers are 7 to 9 inches long. Pepper 'Mama Mia Giallo' F1 is resistant to tobacco mosaic virus.

Pumpkin 'Cinderella's Carriage' F1: This hybrid pumpkin has pink-red colored fruit shaped like the pumpkin carriage from the fairy tale Cinderella. Each plant will yield five to seven yellow fleshed, sweet nutty-flavored, 25- to 35-pound pumpkins. It is great for baking or for fall decorations. Pumpkin 'Cinderella's Carriage' F1 is resistant to powdery mildew.

Tomato 'Chef's Choice Orange' F1: This is an heirloom, indeterminate tomato with almost neon-orange beefsteak-shaped fruit. It will grow 5 feet tall and will yield tomatoes just 75 days from transplanting. The color does not fade when cooked. Tomato 'Chef's Choice Orange' F1 is disease resistant.

Tomato 'Fantastico' F1: This is a determinate bush tomato that will yield around 350 glossy red half-ounce fruits. Some plants will yield up to 12 pounds of fruit. It is great for small gardens, containers, and hanging baskets. Tomato 'Fantastico' F1 is resistant to late blight.

Tomato 'Mountain Merit' F1: This is a medium to large, round red beefsteak tomato that is good for slicing and sandwiches. It will yield tomatoes over a 4 to 5-week period. Tomato 'Mountain Merit' F1 is resistant to multiple diseases.

For more information about the 2014 All-America Selections winners, visit their website at

News Source:

Ron Wolford, 773-233-2900

News Writer:

University of Illinois Extension

Fertilizer in small doses yields higher returns for less money

Published March 6, 2014

URBANA, Ill. - Crop yields in the fragile semi-arid areas of Zimbabwe have been declining over time due to a decline in soil fertility resulting from mono-cropping, lack of fertilizer, and other factors. In collaboration with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), University of Illinois researchers  evaluated the use of a precision farming technique called “microdosing,” its effect on food security, and its ability to improve yield at a low cost to farmers.

“Microdosing involves applying a small, affordable amount of fertilizer with the seed at planting time or as top dressing three to four weeks after emergence,” explained U of I agricultural economist Alex Winter-Nelson. “So, instead of spreading fertilizer over the entire field, microdosing uses fertilizer more efficiently and ultimately improves productivity. Our research shows that smallholder farmers’ investment in microdosing has really unlocked the power of chemical fertilizers in some of the low-rainfall areas of Zimbabwe.”

Training is the key to adoption of the technique.  “About 75 percent of households receiving microdosing training used fertilizer in 2011,” said Winter-Nelson. “This compares to less than 25 percent of households that had not received training. Another way of looking at it is that training in microdosing raised the probability of adoption by 30 to 35 percentage points.  Knowledge of microdosing changed people’s attitudes about fertilizer.  Those who had training generally disagreed with the common notion that fertilizer is not worth its price or that it burns crops.”

Winter-Nelson said that there are some hurdles to overcome, however. “Sustaining and expanding the benefits of microdosing technology will require efforts to ensure that private agrodealers are able to stock the product in a timely manner and to package it in a manner that smallholder farmers find useful,” he said. “This is complicated by the financial capacities of agrodealers and by difficulty in projecting fertilizer demand, which varies with rainfall.

“We also need to work on extending training to underserved areas and to train extension personnel in low-rainfall areas,” he said. “Female-headed households were significantly less likely to adopt microdosing than others, possibly reflecting labor shortages or difficulties accessing fertilizer.  Understanding the particular constraints that female farmers face and adapting the methods or the training to their circumstances could also help extend adoption of the technique.”

The research data were collected via a structured household survey in eight districts in semi-arid areas with additional information about fertilizer availability and demand from key informant interviews with local extension service providers, non-governmental organizations, and agrodealers. Focus group discussions were also utilized. The household survey included questions about assets, cropping patterns, agricultural production, training in microdosing, extension techniques, and fertilizer use and adoption, with particular attention paid to management practices and output on cereal plots two previous cropping seasons.

“What was particularly encouraging from the data is that, when comparing the costs of research, development, and promotion of microdosing in Zimbabwe to the gains achieved through a 30 percent adoption rate and an estimated productivity effect, the data suggest an internal rate of return on the investment in microdosing of over 40 percent,” Winter-Nelson said. “And that’s a good motivation to continue to try to get more farmers in Zimbabwe to try microdosing.”

“Impact of Fertilizer Microdosing Research and Development in Semi-arid Zimbabwe” was produced for the International Crops Research Institute for the Semi-Arid Tropics. Other contributors to the report are Jayne L. Stack, Tarisayi Pedzisa, and Brighton M. Mvumi from the University of Zimbabwe.




Additional Images:
  • Farmland in Zimbabwe
  • Farm in Zimbabwe

Top 10 reasons to garden

Published March 6, 2014
reasons to garden

URBANA, Ill. - In our hurry-up, busy world filled with electronic gadgets such as iPhones, tablets and android devices, where does gardening fit in, asked a University of Illinois Extension horticulture educator. 

“The gadgets of gardening aren’t flashy – a shovel, pruners, hoses, and bags of seeds,” said Martha Smith. “All are simple yet practical and guaranteed to bring satisfaction and sustenance.”

A National Garden Bureau survey asked gardeners why they garden and their responses are inspiring.

Below are the top 10 reasons for gardening:

1. Garden for safe, healthy food

Reports of foodborne illnesses and contamination in foods have been widely publicized.  Interest in organic gardening and the availability of organic produce has increased. Consumers are aware of additives and preservatives found in processed foods. An easy solution is to grow your own fruits and vegetables. It’s estimated that during World War II 20 million homeowners had victory gardens that produced close to 40 percent of the fresh produce consumed in the United States. Start your own garden and know that the foods you and your family eat are fresh and safe.

2. Garden for exercise

You can get all the exercise you need in your own backyard for free! Gardening activities provide both cardio and aerobic exercise. Studies show that an hour of moderate gardening can burn up to 300 calories for women, almost 400 calories for men. Mowing the grass is like taking a vigorous walk, bending and stretching to plant a garden compares to an exercise class, and hauling plants and soil is similar to weightlifting. As we age, gardening can help reduce osteoporosis. If you have physical limitations, there are adaptive tools to help you get the job done.

3. Garden for beauty

A garden can enhance any outdoor setting. A house with a nice yard is a pleasure to look at and satisfying to live in. Simply adding a container of colorful flowers to a patio brightens your spirits.  Trees and shrubs not only provide color and shade but shelter for birds and wildlife. Think of the garden as another room to be enjoyed whether you are inside outside the house.

4. Garden to learn

You can learn by reading and you can learn by doing! Getting out and working with plants builds your gardening knowledge. Gardeners find that the more they learn about plants and gardening, the more they want to know. Plant problems lead to learning solutions. Removing a problem plant allows you the opportunity to try something else.

5. Garden to make money

The love of plants can lead to a rewarding job at a local garden center or a large landscape firm or to owning your own business. Whether growing flowers, vegetables, or herbs, there are opportunities to sell your products at local farmers markets or craft shows. Landscaping an investment property can add to the resale value by as much as 15 percent. This “curb appeal” could make the difference between your house selling versus the house next door.

6. Garden to meet people

Gardeners love to share their gardens and their knowledge. Gardening is a great way to expand your social circle. Whether it’s with a neighbor who lives next door or an internet pal on the other side of the world, gardeners love to talk about plants. Meeting other gardeners through garden clubs and sharing surplus plants is an easy way to share information, ask questions, and get involved.

7. Garden to be creative

Gardening provides an outlet for creative and artistic expression. The serene contemplative mood of a Japanese garden or the romantic feel of a cottage garden – let your creativity flow!  Try something new every season. How about a new annual or a new spring-blooming bulb? Who knows, it may become your all-time favorite plant.

8. Garden to win

For people with a competitive streak, gardening is a friendly way to show off their skills. County and state fairs provide an opportunity to show everyone the giant pumpkin, beautiful bountiful beans, or the perfect zinnia. 4H clubs promote gardening, offering educational opportunities for kids and a healthy avenue for recognition.

9. Garden for emotional needs

Gardens play an important part in our well-being. A garden might serve as a tranquil retreat or private escape from the demands of everyday life. A beautiful bouquet can lift the spirits.  Pulling weeds can be a great stress reliever. A healthy harvest provides a sense of achievement and feelings of success. Gardening builds confidence and self-esteem.

10. Garden for lasting memories

Gardening is a great activity that can be shared with children and grandchildren – the gardeners of tomorrow.  Memories of past gardens and gardeners are cherished. Help build these memories for the next generation. Today’s kids are missing the joy of cutting a bouquet of flowers for their mom or tasting the sweetness of a cherry tomato picked right from the plant in Grandpa’s garden.

“Whatever your reason – get out and garden,” Smith said.  “Turn off the television and put down that electronic gadget. Don’t tell yourself you don’t have the time. Find the time and enjoy.”

News Writer:

University of Illinois Extension

Look back at U.S. soybeans shows genetic improvement behind increased yields

Published March 5, 2014
soybean rows

URBANA, Ill. – Soybean improvement through plant breeding has been critical over the years for the success of the crop. In a new study that traces the genetic changes in varieties over the last 80 years of soybean breeding, researchers concluded that increases in yield gains and an increased rate of gains over the years are largely due to the continual release of greater-yielding cultivars by breeders.

“This research in some ways looks back and informs us how soybean varieties have changed. It’s useful to document these traits and changes,” said Brian Diers, a University of Illinois plant breeder and researcher on the study. “We can show that we really have been successful at increasing yield.”

But this study is also about the future of the soybean crop.

“The study has actually created quite a lot of interest among soybean breeders because they want to understand what’s happened, and when we look at physiological traits, we can see what has been changed. This gives us clues about what traits we should focus on in breeding for future increases based what has been inadvertently changed over time as we have selected for yield,” he said.

Diers and a multi-institutional team of researchers evaluated historic sets of 60 maturity group (MG) II, 59 MG III, and 49 MG IV soybean varieties, released from 1923 to 2008, in field trials conducted in 17 states and one Canadian province during 2010 to 2011.

The experiments included plant introductions (PIs) and public cultivars obtained from the USDA Soybean Germplasm Collection housed at the National Soybean Research Center at the U of I, as well as from varieties provided by Monsanto, Pioneer, and Syngenta.

In the process of documenting the genetic changes, the researchers observed an increase in yields over the past 80 years that is equivalent to one-third of a bushel per acre per year increase.

Diers said that the researchers estimated that about two-thirds of the yield increases in farmer’s fields are due to new varieties that breeders have introduced with the other third due to other reasons such as improved agronomic practices.

“When we compare old varieties to new varieties, the new varieties do yield much better than the old varieties. When we look at the data more closely, the yield increases have actually accelerated starting in the 1960s and 1970s. It’s different for each maturity group, but current yield increases are greater than they were earlier,” Diers said.

This research also showed that when compared to old varieties, plants in the new varieties are shorter in height, mature later, lodge less, and have seeds with less protein and greater oil concentration. 

“The new varieties tend to mature later within these maturity groups, which is something that theoretically shouldn’t happen because we classify these varieties based on when they mature. So theoretically MG II varieties should mature at the same time now as one back in the 1970s, but this is not the case,” Diers said. “Probably over time, people have been selecting varieties that are a little bit later and later, and these changes have accumulated. In some ways, it’s not a bad thing, because farmers are planting earlier than they did back in the 1970s so they actually need varieties that will mature later than back then. That’s not a bad thing.”

Other traits reported as changed over time included earlier flowering time, which has resulted in an expanded reproductive period. “We didn’t know that this reproductive period was expanding, and we are now asking whether breeding for an even longer reproductive period could further increase yields. Other studies have looked at the interaction of planting date by year of release and have shown new varieties can utilize earlier planting dates better than old varieties,” Diers said.

With soybean being a leading source of protein and oil for human food, animal feed, and other products, global rates of yield increases for the crop will need to keep up with demand in the future.

“By understanding how we’ve made these changes to date, it can help us understand how we can further improve yields and increase the rate of gain,” Diers said.

Diers plans to study ways to increase the rate of genetic gains using more modern breeding techniques.

“Most of the yield increases are the result of breeders selecting better combinations of genes that can allow plants to take sunlight and produce more seed from that sunlight. We don’t know what genes breeders are selecting that are resulting in these increases, for example, where in that pathway from the sunlight hitting the canopy to producing seed where this occurs. Breeders, by selecting new varieties that have more yield, are able to make this progress without really understanding the mechanism,” Diers said.

The study, “Genetic Improvement of US Soybean in Maturity Groups II, III, and IV,” was recently published in the Journal of Crop Science and can be accessed online at

Co-authors of the study include Keith Rincker, Randall Nelson, James Specht, David Sleper, Troy Cary, Silvia R. Cianzio, Shaun Casteel, Shawn Conley, Pengyin Chen, Vince Davis, Carolyn Fox, George Graef, Chad Godsey, David Holshouser, Guo-Liang Jiang, Stella K. Kantartzi, William Kenworthy, Chad Lee, Rouf Mian, Leah McHale, Seth Naeve, James Orf, Vaino Poysa, William Schapaugh, Grover Shannon, Robert Uniatowski, Dechun Wang, and Brian Diers.