2020
Identification of New Sources of Resistance / Tolerance of Sclerotinia sclerotiorum among soybean germoplasm showing resistance to Phytophthora sojae
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Contributor/Checkoff:
Maryland Soybean Board
Category:
Sustainable Production
Keywords:
Crop protectionDiseaseField management
Parent Project:
Identification of New Sources of Resistance/Tolerance to Sclerotinia sclerotiorum among Soybean Germplasm Showing Resistance to Phytophthora sojae (root rot)
Lead Principal Investigator:
Kathryne Everts, University of Maryland
Co-Principal Investigators:
Project Code:
Contributing Organization (Checkoff):
Maryland Soybean Board
$19,488
Institution Funded:
University of Maryland
$19,488
Brief Project Summary:

One of the most practical and reliable methods for controlling plant disease is to use disease-resistant varieties. However, only limited sources of natural tolerance have been reported showing moderate resistance against Sclerotinia stem rot in soybean. This project’s goal is to identify new sources of Sclerotinia stem rot resistance in soybean, and to provide soybean breeding programs with germplasm containing that resistance. Work intends to characterize S. sclerotium isolates from soybean and other crops in the Delmarva region and evaluate soybean germplasm for resistance to Sclerotinia stem rot under greenhouse conditions.

Key Benefactors:
farmers, agronomists, Extension agents, soybean breeders, seed companies

Information And Results
Project Deliverables

Final Project Results

Update:

View uploaded report Word file

Sclerotinia stem rot of soybean caused by Sclerotinia sclerotiorum (Lib.) de Bary is an important disease in soybean-production areas of the United States. The disease is endemic in the mid-Atlantic region of the U.S. where common rotational crops are also hosts, including common bean, lima bean, canola, tomato, and pea. In addition, weather, including moderate to cool temperatures during parts of the growing season, and relative humidity greater than 80% that exist in the region are highly favorable for stem rot development
Of the 40 isolates of S. sclerotium collected from soybean and other crops in Delaware, Maryland, and adjacent states, the mycelial compatibility groupings (MCG) of the population appear similar to those in other regions. The similarity of the population, at least for MCG, to other populations is important for guiding management decisions. It is an indication that our populations of S. sclerotiorum in the Mid-Atlantic region may be genetically similar to populations in other areas of the country.
Phytophthora sojae-resistant soybean germplasm lines and soybean accessions from the USDA Soybean Germplasm Collection were evaluated. The "straw" test was conducted at the Plant Science and Landscape Architecture greenhouse at University of Maryland College Park in 2018, 2019, 2020 and 2021. To challenge the soybean lines, we selected four isolates of S. sclerotiorum that varied in aggressiveness in previous tests. Each trial used two of these isolates. Germplasm lines were grown in the research greenhouse, in controlled conditions, inoculated individually with one isolate of S. sclerotiorum per plant, and rated for the disease severity. The test was repeated on each line two or three times over the project period. Among the Phytophthora sojae-resistant soybean germplasm lines that we evaluated, we identified several that appear less susceptible to Sclerotinia stem rot. Germplasm that developed significantly shorter stem lesions than the susceptible check, Williams, included PI378702, PI417015, PI407162, PI567336, PI96983 and PI603170.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.