More than three dozen alfalfa growers in eastern South Dakota have the option of improving their yield next year as a result of a research project conducted this summer at Dakota State University.
Known for its cyber program, not its ag research, the university was the site of groundbreaking work by Andrew Sathoff, assistant professor of biology, and two undergrad biology majors, Jenni Giles and Conner Tordsen. They conducted an alfalfa disease survey focusing on Aphanomyces root rot, a fungus that can live in the soil for as long as a decade. Over the course of the summer, they checked 43 sites in 15 counties.
"We found it in 10 out of the 15 counties surveyed," Sathoff said.
In Lake County, not only did the researchers find the fungus, but they also found two races. In biology, a race is a distinct genetic type within a species or subspecies. Learning that both are found in their fields enables farmers to choose the right variety of seed.
"A lot of varieties are only resistant to Race 1. We also found Race 2, so they might still have trouble getting alfalfa established," Sathoff explained.
The research project was funded through a grant from Mustang Seeds, so the researchers began their project this summer by contacting growers on a list provided by the seed company. A number of them suspected a problem, according to Tordsen.
"They were having trouble getting it [the alfalfa] established," he said.
Once the sites had been identified, Giles and Tordsen headed out to get soil samples.
"It was at least a couple thousand miles they drove," Sathoff indicated.
When they returned to the lab, they attempted to grow alfalfa in the soil samples using growth chambers. Although they look like refrigerators, the growth chambers allow both light and temperature to be regulated. The chambers were set for 16-hour days at approximately 75 degrees, with nights set for 66 degrees.
"We're growing the plants and looking for symptoms," Sathoff explained.
The affected root was then cut off and placed in a petri dish with a synthetic medium which promotes fungal growth. Once that occurs, a DNA test is run to confirm the presence of Aphanomyces root rot.
For the student researchers, the first step was establishing protocols since research of this nature was being conducted for the first time at DSU. Initial results did not produce the expected results.
"We knew what it was supposed to look like, but we weren't getting any positive results," Tordsen said.
They learned they were not extracting enough DNA to get results from the testing. Once they had established the appropriate protocols, they were able to get the desired results. The testing was followed by practical application.
"After we get the results back, we call all the growers and let them know the results," Giles said.
Once the Aphanomyces has been identified, farmers have a couple of options. They can choose a variety of alfalfa which is resistant to the fungus, which has a tendency to grow over time so the concentrations increase, or they can rotate their crops.
"You can grow corn on it for a while so some of the pathogens die," Sathoff indicated.
While the fieldwork is wrapping up for the season for the team of researchers, their work is not done. Because it is the first study of this nature conducted in South Dakota, they are preparing a paper for publication in a peer-reviewed journal called Plant Disease.
"It will be published as a first report," Sathoff indicated. In addition, they will be making a presentation at Dealer Days for Mustang Seeds.
Both Giles and Tordsen are also continuing what Sathoff has identified as graduate-level projects. Giles is currently conducting a review of the literature to identify best practices.
"Writing a literature review is a thankless task. It's usually a grad student's first publication," Sathoff said.
In addition, Giles has applied for a Student Research Initiative grant through DSU to conduct a study similar to the one which was done this summer. Rather than looking for Aphanomyces root rot, she will be looking for phythium, a leading cause of seed rot and seedling blight in alfalfa. She will be using soil samples taken this summer.
Tordsen is also seeking a Student Research Initiative grant, but he intends to continue the summer research project by testing Koch's postulates, which were developed by Robert Koch in the 19th Century as guidelines for identifying pathogens. His project will involve isolating the Aphanomyces DNA, having it sequenced, reinfecting soil and then growing alfalfa in that soil to see if it is affected.
Both students were grateful for the opportunity provided by the summer project.
"It was a great opportunity to learn a lot of different lab techniques," Giles said.
Tordsen echoed that, noting that in classes everything is set up for an experiment, but the research project provided the opportunity to experience the entire process.
So while farmers in Beadle, Brookings, Brown, Clark, Codington, Deuel, Faulk, Hamlin, Kingsbury, Lincoln, Miner, Minnehaha, Moody, Spink and Lake counties benefited from DSU's first ag research project, so did the students involved. That's the kind of winning outcome that Sathoff was seeking when he initiated conversations with Mustang Seeds.