Evaluation of soybean germplasm for resistance to Fusarium virguliforme, the major pathogen causing sudden death syndrome of soybean in the United States

Authors: Herman, Theresa; Bowen, Charles; Mahan, Adam; Hartman, Glen

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2022
Publication Date: 12/16/2022
Citation: Herman, T.K., Bowen, C.R., Mahan, A.L., Hartman, G.L. 2022. Evaluation of soybean germplasm for resistance to Fusarium virguliforme, the major pathogen causing sudden death syndrome of soybean in the United States. Crop Science. 63(3):1344-1353. https://doi.org/10.1002/csc2.20903.
DOI: https://doi.org/10.1002/csc2.20903

Interpretive Summary: Sudden death syndrome (SDS) is one of the most important yield limiting diseases of soybean in the United States. The disease is caused by a soil inhabiting fungus. Occurrence of SDS has increased steadily since the first report of the disease in the United States in 1971. Host resistance is among the most sustainable tools to reduce losses to SDS, and screening soybean accessions for sources of resistance is a fundamental part of discovering host resistance. This study evaluated 10,144 soybean plant introductions (PIs) in all soybean maturity groups for resistance to Fusarium virguliforme which causes of SDS. Using a tiered testing sequence and a seedling layered inoculum method in the greenhouse, new sources of resistance were identified. In the last tier of testing, 16 PIs had mean foliar severity ratings not significantly different from PI 567374, the resistance check; five of the PIs had greater relative dry shoot, root, and total weight than PI 567374. The highly resistant entries reported here will be useful for further studies to understand the resistance mechanisms to F. virguliforme and for breeding programs focused on increasing SDS resistance in elite breeding lines. This information is useful to soybean breeders, geneticists, and pathologists that have interest in improving soybean disease resistance for soybean producers.

Technical Abstract: Sudden death syndrome (SDS) is one of the most important yield limiting diseases of soybean [Glycine max (L.) Merr.]. In North America, the most common causal species is Fusarium virguliforme O'Donnell & T. Aoki. Yield losses of up to 80% have been reported. Host resistance is among the most sustainable tools to reduce losses to SDS, and screening soybean accessions for sources of resistance is a fundamental part of discovering host resistance. This study evaluated 10,144 soybean plant introductions (PIs) in soybean maturity groups (MGs) 000 to X for resistance to F. virguliforme. Using a tiered testing sequence and a seedling layered inoculum method in the greenhouse, new sources of resistance were identified. In tier VI, 60 of 127 PIs evaluated had mean foliar severity equal to or lower than a standard resistant check, PI 567374. In tier VII, 20 PIs with low foliar severity and representing a range of MGs were further evaluated for foliar response, as well as dry shoot and root weights expressed as a percentage of respective non-inoculated plants, or “relative dry weights.” At 28 DAP, 16 PIs had mean foliar severity ratings not significantly different from PI 567374; five of these PIs, 279081, PI 307847, 506757, 507568, and PI 594696B, had greater relative dry shoot, root, and total weight than PI 567374. The highly resistant entries reported here will be useful for further studies to understand the resistance mechanisms to F. virguliforme and for breeding programs focused on increasing SDS resistance in elite breeding lines.