Database Research Summaries2018 Monitoring Virulence Changing of Soybean Cyst Nematode and Evaluating Soybean Varieties for Resistance to New Virulent Type
Research Focus
The focus of this project is to sample twenty-one SCN-infested fields in seven other counties where new virulent types were not reported to further investigate virulence diversity of SCN in ND.
Objectives
- Monitor virulence changing of SCN in seven counties where new virulent types were not reported.
- Screen forty soybean varieties for resistance to the new SCN virulent type detected in Cass County, ND.
Results
- Among the samples collected, 34 were positive for SCN. The average density of SCN eggs in these positive samples was 4,035 eggs per 100 cm3 of soil. The highest density was prevalent in a Traill county soybean field at 42,500 eggs per 100 cm3 of soil. The lowest density of 100 eggs per 100 cm3 of soil was prevalent in soybean fields of several counties surveyed.
- All the HG type experiments performed with naturally infested soil had greater than 100 SCN white females on the susceptible check, indicating 100% experimental success. Among these, the most common HG types were HG 0 (frequency rate: 29%) and HG 7 (29%) followed by HG 2.5.7 (18%), HG 5.7 (12%), HG 2.7 (6%), and HG 1.2.5.7 (6%).
- Prior to this study, PI 548402 was not reported susceptible to SCN; however, during 2017 at least one field from Traill County had a SCN population that reproduced well on PI 548402 (Peking source of resistance), along with PI 88788 (major source of resistance), PI 209332, and PI 548316.
- The new virulent type that was tested in 2017 was confirmed as HG type 2.5.7. We found that 32 out of 37 varieties and lines showed susceptible reactions (female index ranging from 77 to 437), four of them showed moderately susceptible reactions (from 44 to 59), and only one cultivar showed a moderately resistance reaction with female index of 26. This indicates that it is necessary to screen additional soybean varieties and lines for identifying resistance against the new virulent type detected in ND.
Importance
- Monitoring virulence changing of SCN populations is important to navigate the use of resistance sources for growers and the new resistance sources that should be introduced to ND.
- This information is important to help growers select the resistant varieties for controlling this nematode disease to increase soybean yield.
For more information about this research project, please visit the National Soybean Checkoff Research Database.
Funded in part by the soybean checkoff.
