Degree Type

Creative Component

Semester of Graduation

Spring 2021



First Major Professor

Dr. Greg Tylka

Second Major Professor

Dr. Allen Knapp


Master of Science (MS)




Soybean cyst nematode (Heterodera glycines Ichinohe; SCN) is one of the most devastating diseases of soybeans (Glycine max [L.] Merr.) in the United States. This disease is challenging to manage due to the lack of symptoms above ground and the lack of availability of soybean varieties with diverse SCN resistance genes that could be grown long term to slow development of SCN populations with increased reproduction. Soybean seed treatments have become an added tool for SCN management. For farmers to continue to grow soybean profitably in SCN-infested fields, SCN management needs to incorporate non-hosts crops, seed treatments, and soybean varieties developed with new resistance genetics. In this study, four field experiments were conducted in 2020 examining the effects of soybean varieties with different sources of resistance to SCN treated with different seed treatments on soybean yields and SCN population densities. The experiments were conducted in Mower (location 1), Dakota (location 2), Le Sueur (location 3), and Olmsted (location 4) Counties, Minnesota in fields that growers believed were infested with SCN. Yield data from one experiment was not used because of hail damage and another experiment had no detectable SCN population densities. There were no significant treatment effects on yield in the three experiments from which yield data were obtained. In the experiment at location 1, the SCN population densities at the end of season were significantly lower where soybeans with the Peking source of resistance were grown compared to soybeans with the PI88788 source of resistance and susceptible soybeans. Furthermore, SCN population densities for the variety with the PI89772 SCN source of resistance were similarly low and not significantly different from those with the Peking variety. In the experiment at location 2, the SCN population densities at the end of the season collected from soil sampling section 3 were significantly higher than soil sampling sections 1 and 2. There were no significant differences in SCN egg population densities among treatments for location 3, and SCN data from location 4 were not analyzed due to absence of SCN. Although this study did not detect significant treatment differences or interactions with respects to yield, the issue still stands that many growers are not aware of the impact SCN can have on their soybean yields and how there are ways in order to manage this disease, including adding seed treatments such as Saltro® and ILEVO® and planting SCN-resistant varieties with unique sources of SCN resistance, such as PI89772 and Peking.

Copyright Owner

Deitloff, Nicole

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Included in

Agriculture Commons