Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/31/2001
Publication Date: 12/20/2002
Citation: MUELLER, D.S., HARTMAN, G.L., NELSON, R.L., PEDERSEN, W.L. EVALUATION OF GLYCINE MAX GERMPLASM FOR RESISTANCE TO FUSARIUM SOLANI F. SP. GLYCINES. PLANT DISEASE. 2002. v. 86. p. 741-746 Interpretive Summary: Sudden death syndrome (SDS) of soybean is caused by the soilborne fungus Fusarium solani f. sp. glycines. Identifying new sources of resistance in the USDA Soybean Germplasm Collection may improve resistance to Fusarium solani f. sp. glycines of modern soybean cultivars. The objectives of this study were to identify resistance to F. solani f. sp. glycines based on severity of SDS foliar symptoms in 6,037 plant introductions (PIs) from the USDA Soybean Germplasm Collection and to screen selected moderately resistant PIs against several isolates of Fusarium solani f. sp. glycines. Only 60 PIs had foliar disease ratings equal to or lower than previously reported resistant checks. Moderately resistant PIs with different agronomic traits that were inoculated with five isolates of Fusarium solani f. sp. glycines had little variation for foliar symptoms among PIs within each isolate. This research is significant in that it identifies potentially new sources of resistance in PIs and provides data indicating that isolates do not cause detectable differences in foliar symptoms. The impact of this research should benefit other soybean researchers working on SDS, seed producers and growers.
Technical Abstract: Sudden death syndrome, caused by Fusarium solani f. sp. glycines, has caused increased losses in soybean production in recent years. This study was done to identify potential sources of sudden death syndrome resistance. Over 6000 soybean plant introductions (PIs) were compared to a susceptible check, Great Lakes 3302, and two moderately resistant checks, PI 520.733 and PI 567.374. Only 60 PIs had foliar disease ratings equal to or lower than (P<0.05) PI 520.733 and PI 567.374 three weeks after inoculation. Also, 14 PIs had significantly lower disease severity ratings than PI 520.733 and six PIs had lower ratings than PI 567.374 four weeks after inoculation. Lesion lengths were measured four weeks after inoculation and ranged from 25.2 to 41.5 mm for all the PIs. None of the accessions had smaller lesion lengths than the susceptible check Great Lakes 3302. The correlation between lesion length and disease foliar severity rating was not significant. There also was no plant morphological characteristic associated with higher sudden death syndrome foliar symptoms. Eighteen moderately resistant PIs with differing agronomic traits were inoculated with five different isolates of Fusarium solani f. sp. glycines. There was very little variation for foliar symptoms among PIs within each isolate. However, there was variation for symptom intensity among isolates. Isolate Mont-1 caused the greatest disease severity ratings.