Project Details:

Title:
Developing an integrated management and communication plan for soybean SDS

Parent Project: Developing an integrated management and communication plan for soybean SDS
Checkoff Organization:North Central Soybean Research Program
Categories:Soybean diseases, Research coordination, Communication
Organization Project Code:
Project Year:2015
Lead Principal Investigator:Daren Mueller (Iowa State University)
Co-Principal Investigators:
J. G. Arbuckle (Iowa State University)
Silvia Cianzio (Iowa State University)
Leonor Leandro (Iowa State University)
Gregory Tylka (Iowa State University)
Martin Chilvers (Michigan State University)
Albert Tenuta (Ontario Ministry of Agriculture-Food & Rural)
Jamal Faghihi (Purdue University)
Virginia Ferris (Purdue University)
Kiersten Wise (Purdue University)
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Keywords: Fusarium virguliforme, Sudden Death Syndrome (SDS)

Contributing Organizations

Funding Institutions

Information and Results

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Project Summary

The foundational management strategy for sudden death syndrome (SDS) is using resistant cultivars. Some years when environmental conditions were favorable for disease development, it is evident that resistance alone does not provide adequate control or reduce farmer risk sufficiently. The main goal of this project is to investigate management options that will help ensure resistant cultivars that will be as effective as possible, thereby reducing risk as well as providing farmers with maximum economic return on their investment even in unusually conducive SDS conditions.

This project has a direct benefit to soybean farmers in the North Central region by providing evaluations of current and future crop production practices/products and how these practices will either fit into an integrated pest management (IPM) strategy for SDS, or affect the ability of resistant cultivars to manage SDS, thus reducing economic losses to producers through better management of SDS.

Project Objectives

1. Evaluate if soybean root health can be improved to reduce SDS or be used as an indicator of SDS risk.
2. Determine how shifts in soybean production practices affect the risk of SDS development.
3. Communicate research results to farmers, agribusinesses and other soybean stakeholders.

Project Deliverables

Over this past 6 months, we were able to make great progress in each objective. Here are the highlights.
1. Completed a second year of data on the interaction between herbicide and seed treatment on SDS. Data are being summarized.
2. Published a multi-lab study evaluating performance of six qPCR assays developed for F. virguliforme in Phytopathology. In this study, we compared the strengths and weakness of six assays under different research facilities and also identified an effective protocol for better diagnosis and quantify SDS pathogen.
3. Compared seed treatments to reduce SDS foliar symptoms. In this study, we evaluated different fungicide products and application methods to see if any would complement cultivar resistance. So far, we found that the ILeVO® seed treatment or in-furrow was effective at reducing SDS severity levels in many different environments compared to control plots. Manuscript is being written for publication in peer-reviewed journal.
4. Completed a study evaluating planting date and seed treatment effect on SDS. Manuscript will be submitted for publication in next couple months. To summarize, ILeVO seed treatment reduced disease severity and increased yield nearly in all plantings and cultivars, with a maximum yield response up to 21% (Roland Iowa). Effect of planting date on foliar SDS symptoms was inconclusive.
5. Completed field experiments on determining how increasing SCN resistance to SCN-resistant cultivars will affect SDS resistance performance. Data collection and analysis are on process.
6. Presented our preliminary research at professional meetings, on Plant Management Network, gave national and international seminars, media interviews, talk in field days and conferences for farmers and also published in state newsletter articles, 20+ media releases etc. To communicate we also published in peer-reviewed journals.

Progress of Work

Update:
A population of 153 lines and a validation population of 167 lines were tested for SDS resistance in a disease nursery in Decatur, Michigan and with genetic markers to map new SDS resistance genes (these are known as QTL or quantitative trait loci). A high level of disease was observed in these tests and these results will be useful for mapping resistance genes.

Five SDS resistance genes were mapped using a new method of genetic mapping called association mapping. Three of these genes were mapped to regions where SDS resistance genes were previously mapped.

Field test were done to confirm the effect of previously mapped SDS resistance genes. The effect of three genes was confirmed which means that these genes will be especially useful in breeding programs.

The identification of genes with expression related to SDS resistance is ongoing. This is being done using pairs of soybean lines that are almost genetically identical except for two SDS resistance genes. These lines were inoculated with the fungus that causes the disease and RNA was isolated from these plants and the samples are being prepared for analysis.

Update:
We examined the effect of glyphosate on SDS. Study has been published in Plant Disease. Study of effect of interaction between herbicide and seed treatment on SDS is ongoing. We collected and analyzed the first year data.

We completed a multi-lab study evaluating performance of six qPCR assays developed for F. virguliforme. The manuscript was submitted for publication to Phytopathology. In this study, we compared the strengths and weakness of all six assays under different research facilities in terms of their specificity, sensitivity, and consistency and also identified an effective protocol for better diagnosis and quantify SDS pathogen. To summarize, assays differed in their performances and also the performance of the same assay varied among the laboratories. An assay developed in Chilvers lab showed the highest sensitivity and the second highest specificity, and thus is suggested as the most useful qPCR assay for F. virguliforme. This assay is currently being used for quantifying F. virguliforme population in root and soil in other objectives.

We identified seed treatments to reduce SDS foliar symptoms. We completed a study evaluating planting date and seed treatment effect on SDS development. Manuscripts are being written to peer-reviewed journals. To summarize, ILeVO seed treatment reduced disease severity and increased yield nearly in all plantings and cultivars, with a maximum yield response up to 21% (Roland Iowa). Effect of planting date on foliar SDS symptoms was inconclusive. Although Mid-June plantings did not have higher disease than early plantings it yielded lower grain up to 19 bu/A compared to early May plantings.

We evaluated different fungicide products and application methods to see if any would complement cultivar resistance Manuscript is being written for publication in peer-reviewed journal. We are continuing this study in 2015 replacing some products and foliar applications with new chemical and biological products. From this study, the main conclusion was that ILeVO seed treatment and Luna Privilege in-furrow were effective at reducing SDS severity in many different environments compared to the control. Foliar applications of any chemicals had no effect on SDS.

We collected SCN, SDS and yield data from all participating states and data analysis is being done. We will continue this experiment in 2015 as well. However, so far we found varieties with Peking source of resistance for SCN had lowest SDS in many environments and varieties with no resistance to SDS and SCN had the highest disease.

We presented our preliminary research at professional meetings, on Plant Management Network, gave national and international seminars, media interviews, talk in field days and conferences for farmers and also published in state newsletter articles, 20+ media releases etc. To communicate with researchers, we also published or are in the process of publishing in peer-reviewed journals. We also had several press releases, including some jointly with NCSRP, based on results from this project (e.g., glyphosate study, ILeVO study).

Final Project Results

1. We completed a multi-lab study evaluating performance of six qPCR assays developed for F. virguliforme and the manuscript has been published in Phytopathology. In this study, we compared the strengths and weakness of all six assays under different research facilities in terms of their specificity, sensitivity, and consistency and also identified an effective protocol for better diagnosis and quantify SDS pathogen. To summarize, assays differed in their performances and also the performance of the same assay varied among the laboratories. Overall, A single copy gene (FvTox1)-based assay showed the highest specificity (with lowest false positives), while multi-copy gene based assays were more sensitive (with their ability to detect very small amount). A recent assay developed in chilvers lab showed the highest sensitivity and the second highest specificity, and thus is suggested as the most useful qPCR assay for F. virguliforme. This assay is currently being used for quantifying F. virguliforme population in root and soil in other projects.
2. Effect of planting date on SDS e.g., how mid- or late April planting compares with early to mid-May plantings, is better understood. We completed this study comparing effect of planting date and seed treatment on resistant and susceptible cultivars. To summarize, ILeVO seed treatment reduced disease severity and increased yield nearly in all plantings and cultivars, with a maximum yield response up to 21% (Roland Iowa). Effect of planting date on foliar SDS symptoms was inconclusive. Although Mid-June plantings did not have higher disease than early plantings it yielded lower grain up to 19 bu/A than early May plantings.
3. We also evaluated different fungicide products and application methods to see if any would complement cultivar resistance. From this study, the main conclusion was that ILeVO® seed treatment or in-furrow was effective at reducing SDS severity levels in many different environments compared to control plots. Foliar applications of any chemicals including ILeVO showed no effect on SDS reduction.
4. Information on the importance of early season root and soil health on SDS development is generated that will elucidate i) If increased nematode reproduction on SCN resistant cultivars based on PI88788 resistance need to be considered in SDS management decisions. We are still collecting data on SCN, SDS and yield and it will be summarized as soon as the data are collected. So far we found varieties with Peking source of resistance for SCN had lowest SDS in many environments and varieties with no resistance to SDS and SCN had the highest disease.
5. Understanding for farmers and agronomists on shifts in herbicide regimes and the associated effect on SDS risk is improved. Our study suggested that glyphosate had no association with SDS incidence or severity. Farmers will be able to make informed decisions regarding herbicide choice for the weed management strategy.
6. Effect of seed treatment and herbicide interaction on root health and SDS will be better understood. Seed treatment effectiveness in light of different management strategies for example different soil-applied herbicides, different cultivars, and other crop cultivation strategies are being investigated.
7. We improved existing NCSRP resources to better communicate with farmers, agribusinesses and other soybean stakeholders. We will also evaluate the impact of our management and educational efforts.

Benefit to Soybean Farmers

This project has a direct benefit to soybean farmers in the North Central region by providing evaluations of current and future crop production practices/products and how these practices will either a) fit into an integrated pest management (IPM) strategy for SDS; or b) affect the ability of resistant cultivars to manage SDS, thus reducing economic losses to producers through better management of SDS.

Farmers will have new management tools available. They will have information available regarding how shifting in crop cultivation practices for example early planting, change in source of SCN resistance, changing herbicide management strategy affect on SDS. With the new tool to better diagnose and quantify SDS pathogen in root and soil, farmers will have options to better diagnose and quantify fungal load in their fields that might help to assess risk of SDS in coming years.

Performance Metrics

Project Years