Soybean Cyst Nematode Research: Small organism, big research impacts
While an individual nematode may be small, and is often microscopic, the impact these organisms can have on plant communities is immense. Nematodes are the most abundant multicellular animals on Earth, and while many of them are beneficial to plant communities, some are serious threats to agricultural crops.
Professor Senyu Chen’s, research focuses on one of the most destructive plant-parasitic nematodes in the world, the soybean cyst nematode (SCN). In Minnesota, SCN is a major limiting factor for soybean yield, and it has been found in approximately 60 percent of soybean fields statewide.
Historically, SCN has been effectively managed through genetic resistance in soybeans. However, if the same type of resistance is continuously used for a number of years, this can select the nematode individuals that can reproduce on the resistant cultivars, leading to the development of a population that can eventually overcome the resistance. Unfortunately, in Minnesota, after a number of years (more than two decades) primarily using SCN resistant cultivars from a single source of resistance, many SCN populations have shifted to types that can overcome the resistance in commercial cultivars.
For this reason, Chen and his lab are studying the long-term interactions between resistant cultivars and the SCN population in Minnesota soybean production systems. They are searching for new sources of SCN resistance with the goal of developing soybean lines and cultivars with these new sources of resistance.
However, due to the complexity of SCN, Chen says that genetic resistance alone will not provide a long-term solution to SCN.
“In spite of the availability of a number of resistant cultivars, SCN continues to cause yield loss in soybeans because of the complexity of the organism. If we are to work toward a long-term solution, effective management strategies will need to leverage an integrated systems approach,” says Chen.
Chen’s lab also investigates other key strategies such as the cultural, chemical, and biological controls of SCN to gain an understanding of how an integrated management approach could be implemented.
For cultural practices, the lab has investigated practices such as the use of alternative rotation or cover crops, tillage, and agricultural wastes for managing SCN in greenhouses and fields. They have studied how tillage, chemical fertilizer and organic amendments such as swine manure and industrial wastes affect plant-parasitic nematodes, beneficial soil nematodes, and general soil health. To investigate biological control, they are studying microbial communities associated with the SCN, and the effects of long-term agricultural practices on the natural enemies of SCN.
Ultimately, Chen and his lab hope to increase understanding of the ecology of nematodes in agricultural soil ecosystems, and to find long-term management strategies for farmers. The research of Chen’s lab not only aims to enhance crop productivity, but to save the soybean industry from multi-million dollar SCN damage in the future.