Breeding Better Beans
June 1, 2015 Ohio Soybean Council
To those who are unfamiliar, a soybean is simply a soybean. Although anyone involved in production or processing in the soybean industry knows there are numerous varieties with intricate differences. Unique qualities of each variety can often be attributed to researchers who do the tedious work of isolating the genes for each desired quality, breeding them into a specific plant and running trials to ensure they are ready for high yielding production.
At The Ohio State University (OSU), research teams are focused on selective soybean breeding for pathogen resistance and specific traits to bring producers varieties that are more durable and specialized for specific markets as well as Ohio’s growing conditions.
“Here at OSU we have a program that focuses on identifying lines and germplasm that are actually resistant to the many pathogens attacking soybeans,” said Dr. Anne Dorrance, a professor and soybean pathologist at OSU. “From there, we characterize the resistance, how many genes contribute to the expression and what conditions are necessary for the gene to appear.”
Dorrance works largely with water molds, a problem in clay soils where it can take two to three days for rainwater to drain off. In those conditions, the water molds produce swimming spores that can attack the plants. Another disease at the forefront is the same fungus that causes head scab in wheat which can attack soybean seedlings when there is a lot of inoculum present, possibly built up from years of growing susceptible crops in the same fields.
“That’s where our strengths are, those are the primary pathogens; and we have such a diversity of growing conditions here in the state that if something survives our program, they’ll probably survive anywhere,” said Dorrance.
To begin the process of developing host resistance, researchers have to find a variety that has a viable source – most often a soybean line with origins from Asia. These varieties are not suitable for Ohio production, but hold the genes for resistance that will be bred into the high yielding, adapted Ohio lines.
Currently, they are looking at some of the severe foliar pathogens and stem rot pathogens where host resistance – being environmentally friendly, easy to deploy and low cost to producers – is an efficient and viable option. Additionally, there is no chemical treatment for pathogens such as water molds and they may attack the crop all season long, making it very difficult to manage with other methods.
“With breeding, you have your crop that’s all ready to go,” said Dorrance. “We identify lines and in many cases map the traits so we know what markers to follow and we’ll send the line that we’ve already screened to Dr. McHale to do the crosses.”
Focusing on Ohio breeds, the research of Dr. Leah McHale, associate professor in the Department of Horticulture and Crop Sciences at OSU research involves yield trials throughout the state to determine which varieties perform best. A large part of breeding is variety improvement by focusing on specific desirable traits – such as host resistance.
“We focus on a lot of specific traits – improvement of disease resistance, primarily for quantitative, or partial, disease resistance. It’s a trait that involves many different genes contributing a small part of the resistance and is usually considered non-race specific – meaning it will hold up against any race of the pathogen,” said McHale.
With race specific resistance, there may be another race of the pathogen that could overcome the resistant gene. Most cultivars McHale works with have race specific genes in addition to high levels of partial resistance as a built in fail safe. Selective breeding is not only used for host resistance with pathogens, but can be beneficial in dealing with soybean cyst nematode or soybean aphids and is a great way to develop varieties that more closely meet the needs of specialty markets.
“The primary specialty market we work with is the food grade market which consists of developing soybeans for people, as opposed to the crush market for oil and meal,” said McHale. “We work mostly with the soymilk and tofu markets that typically look for high protein, large seeded, clear hilum, smooth seed coats and seed coats free from cracking. More visual characteristics are important for that market.”
Other varieties in development include high oleic with high oil traits, looking at high oleic currently being a smaller and higher value market, the combination with high oil will provide a better value. They are also looking at some specialty oil types in anticipation of specialty products becoming available in the future and knowing the process to get the varieties on the market can take time.
“Our process can range from six to eight years from the time we conduct crosses to the time we release the material,” said McHale. “We have some preliminary phases – we carry out the cross, grow hybrids and then there’s a number of generations of inbreeding carried out so we can develop a uniform line – meaning the seeds from an individual plant will be genetically uniform.”
The inbreeding can take two to four years and is followed by three years of field evaluation in four Ohio locations. Each year the weaker material is weeded out and the resulting material is released through the Crop Variety Release and Distribution Committee. The committee is comprised of researchers, the office of technology and licensing, Ohio Foundation Seeds and Ohio Seed Improvement Association.
The many groups come together to collaborate on the best way to release the cultivars to get them into farmer’s fields – whether it is released as a public, branded, exclusive or non-exclusive cultivar.
In addition to releasing cultivars, there are research and educational components being supported along the way.
“Our research components help us understand the mechanisms, how these traits that we’re breeding for are controlled genetically and ultimately predict how useful it’s going to be when it’s deployed in the field so we don’t get surprised down the road,” said McHale.
The Ohio Soybean Council and soybean checkoff not only allocates funds for these research goals, but also provides a source of farmer feedback and a direct connection to issues producers are facing.
“We support the work at Ohio State because we recognize its importance. They are providing solutions to producer problems and advancing the markets for Ohio soybeans all while supporting research and teaching goals that will provide the next generation of plant scientists for our industry,” said Patrick Knouff, OSC Chairman and soybean farmer from Shelby County.