Project Details:

Improving SCN management through field research on SCN resistant soybean varieties and nematode protectant seed treatments

Parent Project: This is the first year of this project.
Checkoff Organization:Iowa Soybean Association
Categories:Nematodes, Soybean diseases
Organization Project Code:450-46-07
Project Year:2016
Lead Principal Investigator:Gregory Tylka (Iowa State University)
Co-Principal Investigators:

Contributing Organizations

Funding Institutions

Information and Results

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Project Summary

The soybean cyst nematode (SCN) is Iowa’s most damaging soybean pathogen. Yield loss due to SCN can cost Iowa farmers tens to hundreds of millions of dollars annually. The nematode has been found in approximately 74% of Iowa fields, its population densities (numbers) can increase 10 to 50 fold in one year, and it can survive for a decade or more in the absence of soybeans.
Currently there are three primary options for managing SCN:
1) growing nonhost crops (such as corn)
2) growing SCN-resistant soybean varieties
3) using nematode-protectant seed treatments on soybean seeds
The field research proposed in this project will increase the competitiveness of Iowa soybean farmers through better and more sustained management of SCN. That is, SCN-resistant varieties and nematode-protectant seed treatments will be evaluated for agronomic and nematode-control benefits in field experiments conducted throughout the state, resulting in information that Iowa soybean farmers can use to maintain and improve their soybean yields.
The funds requested for this project represent base funding for the Tylka SCN field research program. Personnel in this project also conduct various field and laboratory research activities relating to SCN for the soybean-checkoff-funded projects of six other ISU faculty (S. Cianzio, E. Hodgson, L. Leandro, D. Mueller, A. Robertson, and D. Singh). Also, the experiments with seed treatments in this project will be coordinated with and directly complementary to ISA On-Farm® Network strip trials assessing the effects of the same nematode-protectant seed treatments.
This project addresses the targeted research area of “Soybean disease, nematode, insect pest and abiotic stress biology, management and yield loss mitigation” in the Iowa Soybean Association’s Request for Research Proposals from Iowa State University for 2015-2016 Funding.

Project Objectives

The overall goal of this project is to provide Iowa farmers with the best possible research-based information about varieties and seed treatments for management of SCN. There are three objectives that will be addressed to achieve the goal stated above. The objectives are to study:
1) the agronomic performance and nematode control provided by SCN-resistant soybean varieties being marketed to Iowa soybean farmers
2) the effects of increasing SCN reproduction on yields of SCN-resistant soybean varieties
3) the effects of nematode-protectant seed treatments on agronomic performance and reproduction of SCN on resistant soybean varieties

Project Deliverables

There will be numerous deliverables and outcomes emanating from this project:
• annually updated report of results from the SCN-resistant soybean variety trial experiments (direct mailed to 70,000 Iowa farmers and agribusiness personnel)
• annually updated list of SCN-resistant soybean varieties for Iowa soybean farmers
• articles in the Iowa State University online Integrated Crop Management News newsletter
• articles in the Iowa Soybean Association electronic Advance newsletter

Progress of Work

Project progress from 1 October 2015 through 31 March 2016 included:

- Compiled and prepared a publication titled “Soybean cyst nematode-resistant soybean varieties for Iowa,” posted it online, and promoted its availability and use in an Integrated Crop Management News article titled “Record Number of SCN-Resistant Soybean Varieties Available, More with Peking Resistance” in October 2016 (see

- Harvested research plots in all 9 resistant variety evaluation experimental locations to determine yields in October 2016.

- Collected soil samples from every plot in all 9 resistant variety evaluation experimental locations to determine final SCN soil population densities in October 2016.

- Extracted SCN cysts, then eggs, from samples collected from all 9 resistant variety evaluation experimental locations to determine final SCN egg population densities in November and December 2016.

- Compiled and analyzed yield and SCN population density data from all 9 resistant variety evaluation experimental locations in December 2016.

- Prepared a printed report of resistant variety evaluation experimental results (PDF file attached), and distributed the report to 70,000 Iowans as a special insert in the Iowa Farmer Today magazine in January 2016.

- Began contacting seed companies to request seeds of resistant soybean varieties for 2016 field experiments in January-February 2016.

- Contacted Bayer CropScience and Syngenta personnel for seed treatments for 2016 small-plot field experiments and On-Farm Network strip trial experiments in January- February 2016.

- Began received seed from seed and seed-treatment companies for 2016 field experiments, and design the 2016 field experiments and began packaging of seeds for the various experiments in March 2016.

- Conducted final sampling of fields throughout Iowa to allow for selection of the final 2016 experimental field locations in March 2016.

Final Project Results

Benefit to Soybean Farmers

There is no legal definition of how much soybean varieties must suppress reproduction of SCN in order to be considered “SCN resistant.” And SCN resistance involves numerous genes, so not all SCN-resistant varieties possess the full complement of genes. Therefore, yield and nematode control vary greatly among the hundreds of SCN-resistant soybean varieties from which Iowa soybean farmers have to choose.

In the last decade, nematode-protectant seed treatments (ex. Clariva, Ilevo, Votivo) have begun to be sold to Iowa farmers as an additional management tool for SCN. But increased yields and suppression of SCN reproduction by these seed treatments is not guaranteed to occur.

The research conducted in this project is farmer-focused applied research that is unique in Iowa and the nation in that SCN-resistant soybean varieties and nematode-protectant seed treatments are intensively evaluated under real Iowa field conditions and nematode data are collected from each individual 4-row research plot at the time of planting and again at the time of harvesting. The intensive-scale information emanating from these experiments is not available anywhere else in the U.S. The research results give Iowa soybean farmers first-hand information generated in their state about the performance that can be expected when these SCN-resistant soybean varieties and the nematode-protectant seed treatments are used.

Furthermore, the experiments with nematode-protectant seed treatments are coordinated closely with the Iowa Soybean Association’s On-Farm Network in order to generate a robust set of data from through Iowa to illustrate to Iowa soybean farmers what can be expected in terms of yield increase and SCN reproduction suppression when the seed treatments are used.

Performance Metrics

- Completion of data collection and analysis from nine field experiments distributed throughout Iowa to generate data applicable to Iowa soybean farmers in all areas of the state.

- Compilation of applied, field research results and dissemination of the results directly to 70,000 Iowa farmers and agribusiness personnel.

- Completion and promotion of a publication that provides a single source of information for Iowa soybean farmers of the SCN-resistant soybean varieties that are available to them.

Project Years