Project Details:

Title:
Evaluating Resistant Soybean Varieties and Seed Treatments to Help Iowa Farmers Maintain High Yields in SCN Infested Fields

Parent Project: This is the first year of this project.
Checkoff Organization:Iowa Soybean Association
Categories:Nematodes
Organization Project Code:450-46-09
Project Year:2019
Lead Principal Investigator:Gregory Tylka (Iowa State University)
Co-Principal Investigators:
Keywords:

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 hundreds of millions of dollars or more annually. The nematode has been found in all Iowa counties and up to 86% of Iowa fields (based on random survey results from 2017), its population densities (numbers) can increase 10 to 50 fold in one growing season, and it can survive for a decade or more in the soil 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 conducted in this project increases the competitiveness of Iowa soybean farmers through better and more sustained management of SCN. SCN-resistant varieties and nematode-protectant seed treatments are evaluated for agronomic performance and nematode control in field experiments conducted throughout the state, resulting in information that Iowa soybean farmers can use to help them make seed and seed treatment purchase decisions to maintain and improve their soybean yields.

The funds for this project are base funding for the Tylka SCN field research program at ISU. Personnel in this project also conduct field and laboratory research activities relating to SCN for soybean-checkoff-funded projects of other ISU faculty members. And the experiments with seed treatments in this project are 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 specific objectives, listed below, that will be addressed to achieve the goal stated above:

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, including:
• annually updated report of results from the SCN-resistant soybean variety trial experiments
• annually updated results from experiments assessing the effect of the nematode-protectant seed treatments
• annually updated list of SCN-resistant soybean varieties for Iowa soybean farmers
• annually updated list of nematode-protectant seed treatments for SCN
• articles in the Iowa State University online Integrated Crop Management News newsletter
• articles in the Iowa Soybean Association electronic ISA News E-Weekly newsletter

Progress of Work

Updated March 17, 2019:
- Compiled and prepared a publication titled “Soybean cyst nematode-resistant soybean varieties for Iowa,” posted it online - see https://store.extension.iastate.edu/Product/pm1649-pdf.

- Harvested research plots in all 9 SCN-resistant variety trial experiments and 27 seed treatment evaluation experiments to determine yields in October 2018.

- Collected soil samples from every plot in 8 of the 9 SCN-resistant variety trial experiments and all 27 seed treatment evaluation experiments to determine final SCN soil population densities in October 2018. One variety trial experiment, in southwest Iowa, was too wet to collect soil samples from before winter set in, so SCN data will not be available from that experiment.

- Extracted SCN cysts, then eggs, from 2,952 soil samples collected from the 8 SCN-resistant variety trial experiments and the 27 seed treatment evaluation experiments at harvest, then counted the eggs to determine final SCN egg population densities in November and December 2018.

- Compiled and analyzed yield and SCN population density data from the SCN-resistant variety trial and seed treatment evaluation experiments in December 2018.

- Prepared a printed report of the SCN-resistant soybean variety trial experiment results and distributed the report to 53,250 Iowans as a special insert in the January 12, 2019, issue of the Iowa Farmer Today magazine. The report also is available online - see https://store.extension.iastate.edu/Product/ipm52-pdf.

- - Updated a table of nematode-protectant seed treatments for SCN and posted it online for easy access - see https://www.plantpath.iastate.edu/files/page/files/seed_treatment_table_-_january_2019.pdf

- Began contacting seed companies to request seeds of SCN-resistant soybean varieties for 2019 field experiments in January-February 2019.

- Contacted Nufarm, Valent, and Bayer personnel for Trunemco, Aveo, and Nemastrike seed treatments, respectively, for 2019 small-plot field experiments and On-Farm Network strip trial experiments in January- February 2019.

- Began receiving seed from seed and seed-treatment companies for 2019 field experiments, and designed the 2019 field experiments and began packaging of seeds for the various experiments in March 2019.

- Conducted final soil sampling of farmer fields throughout Iowa to allow for selection of the final 2019 experimental field locations in March 2019.

- Published a scientific paper titled “Effects of Clariva Complete Beans seed treatment on Heterodera glycines reproduction and soybean yield in Iowa” in the online journal Plant Health Progress. The paper was co-authored by ISA’s Peter Kyveryga and also former ISA staff member Tristan Mueller. See https://www.plantmanagementnetwork.org/sub/php/volume19/number1/PHP-08-17-0043-RS.pdf.

View uploaded report PDF file

View uploaded report 2 PDF file

View uploaded report 3 PDF file

View uploaded report 4 PDF file

Final Project Results

Updated September 29, 2019:
- Received seed from seed and seed-treatment companies for 2019 field experiments, designed the 2019 field experiments, and packaged and organized the seeds for the various experiments. The varieties included in the 2019 SCN-resistant soybean variety trial experiments are from ASGROW, Beck’s, Cornelius, Corteva (Pioneer), Federal, GROWMARK FS HiSoy, Hoegemeyer, Kruger, Latham, LG Seeds, Legacy Seeds, Merschman, MFA Incorporated, Mycogen, NuTech, Nutrien Ag Solutions (Dyna-Gro), Stine, and Syngenta (NK).

- Set up, planted, soil sampled, and maintained nine field experiments located throughout Iowa to evaluate the yield enhancement and nematode control provided by 186 SCN-resistant soybean varieties. Some experiments didn't get planted until June 2019 because of wet weather. The latest experiment was planted June 10, 2019.

- Set up, planted, soil sampled, and maintained nine field experiments located throughout Iowa to evaluate the agronomic performance and nematode control provided by three different nematode-protectant seed treatments - namely Aveo (from Valent), Nemastrike (from Bayer), and Trunemco (from NuFarm).

- Extracted SCN cysts (egg-filled dead SCN females), then eggs, from soil samples collected from all 9 resistant variety evaluation experiments and the 27 seed treatment experiments to determine initial SCN egg population densities.

- In late September, began trimming the field research plots at the 36 variety evaluation and seed treatment experiments in preparation for harvesting. Harvest likely will begin the week of October 14, 2019.

- In late August, contacted more than 50 seed companies and gathered information about SCN-resistant soybean varieties to use to update the ISU Extension publication titled “Soybean Cyst Nematode-Resistant Soybean Varieties for Iowa”. This publication will be compiled and released in PDF format by the end of October 2019.

- Submitted a manuscript of a research paper that was accepted by the journal Plant Disease that summarizes three years of coordinated ISA On-Farm Network and ISU small-plot experiments evaluating the agronomic benefit and nematode control provided by Ilevo seed treatment (ISA scientists Peter Kyveryga and Tristan Mueller are co-authors). The manuscript will include yield difference graphs (with versus without Ilevo) using Iowa Soybean Association’s online ISOFAST tool.

View uploaded report PDF file

View uploaded report 2 PDF file

Currently there are three options for managing SCN: 1) growing nonhost crops such as corn, 2) growing SCN-resistant soybean varieties, and 3) using nematode-protectant seed treatments on soybean seeds. Annually, the results of the experiments conducted in this project are useful to Iowa soybean farmers in deciding which resistant varieties and seed treatments to purchase for use in fields infested with SCN. The results of the experiments conducted in 2019 are not yet available because the plots have not been harvested by the date of this report (30 September 2019). The report of 2018 variety trial experimental results and the 2018 list of SCN-resistant soybean varieties for Iowa are attached to this final report.

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.

And in the last decade, nematode-protectant seed treatments (such as Avicta, 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. And there is no requirement for a company to prove efficacy in order to sell a seed treatment claiming nematode control benefits.

The experiments conducted in this project are farmer-focused applied research that is unique in Iowa 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 own 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 throughout 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

- number of variety trial and seed treatment field experiments conducted in 2018 and again in 2019 = 9 and 27, respectively

- number of different soybean varieties evaluated in the variety trial experiments in 2018 - 216 and in 2019 = 186

- number of different brands of seed evaluated in the variety trial experiments in 2018 = 24 and in 2019 = 18

- number of plots planted, maintained, soil sampled, and harvested in 2018 = 3,240 and in 2019 = 2,808

- number of SCN soil samples processed and counted in 2018 = 6,480 and in 2019 = 2,808 so far, with 2,808 more to be done after harvest

- number of Iowa farmers and agribusiness personnel who will receive a printed report of the variety trial experiment results inJanuary 2019 and again in January 2020 = 53,250 each year

Project Years