Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/19/1997
Publication Date: N/A
Technical Abstract: Four soybean plant introductions (PIs) and one soybean cultivar were inoculated under greenhouse conditions with four isolates of Fusarium solani that cause soybean sudden death syndrome. Foliar disease severity was greatest on PI 567.659, followed by cv. Great Lakes 3202, PI 520.733, PI 567.650B and PI 567.374. No significant interaction occurred between isolates and soybean entries. Several experiments were conducted using isolate Mount-1 to determine if entries differed in disease development, degree of root colonization, and differed in their response to uptake of fungal cultural filtrate. Foliar symptoms developed rapidly on PI 567.659 and Great Lakes 3202, and slowly on PI 567.374, which had a significantly (P<0.01) lower area under the disease progress curve (AUDPC) value. There were no differences among the five entries in the number of tap root lesions, dry-weight root loss, and degree of stem length discoloration. AUDPCs based on foliar disease severity of cut seedlings in culture filtrate differed significantly (P<0.001) as the AUDPC PI 567.374 was lower than the other entries. There was a significant (P<0.05) positive correlation (r=0.94) between AUDPC values of the five entries inoculated with the fungus and the cut seedling test using fungal culture filtrate.