Thesis
Verticillium dahliae asymptomatically and differentially infects rotation crops of potato in the Columbia Basin, Washington
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/102850
Abstract
Verticillium dahliae Kleb. is an ascomycetous fungus that infects hundreds of plants, causing Verticillium wilt in some hosts and no symptoms in other hosts. Crop rotation is a potential tactic to control Verticillium wilt; however, some rotation crops may be infected by V. dahliae and contribute to soil inoculum. The hypothesis that rotation crops of potato and mint are asymptomatically infected by V. dahliae was tested by inoculation of rotation crops and isolation of V. dahliae from stems of rotation crops grown in fields with a history of Verticillium wilt. Mustards, sweetcorn, barley, wheat, sudangrass, Austrian winter pea, peppermint, native mint and potato were planted in soil infested with eight isolates of V. dahliae in two experiments. Rotation crops were grown to senescence and inoculum density of V. dahliae was estimated from stems, seed, roots and soil on a semi-selective medium. At least one V. dahliae isolate was detected from all asymptomatic rotation crops. A rotation crop by isolate interaction (P < 0.01) occurred and inoculum density of V. dahliae was different among rotation crops and among isolates within each rotation crop. Stem, root and seed biomass increased, were not affected, or decreased (P ≤ 0.04) in rotation crops inoculated with different isolates of V. dahliae relative to non-inoculated controls. Potato and peppermint were grown in infested soil after rotation crops to simulate crop rotation. Incidence of infected stems of potato and peppermint were restricted to plants grown in soils where potato and mustards where grown. Stem samples of rotation crops grown in 21 commercial fields with a history of Verticillium wilt of potato or mint were collected and tested for V. dahliae to corroborate results. V. dahliae was detected in stems of rotation crops from eight fields (38%). Incidence of infected stems was 0% in arugula, buckwheat, dill, pea, beans, timothy, oats, and corn, 1% in corn, 2% in millet and wheat, 8% in buckwheat, 10% in barley, 24% in sunflower, 6% in white mustard and,14 and 63% in brown mustard fields. Based on these results specific rotation crops are asymptomatically and differentially infected by isolates of V. dahliae.
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Details
- Title
- Verticillium dahliae asymptomatically and differentially infects rotation crops of potato in the Columbia Basin, Washington
- Creators
- David Linnard Wheeler
- Contributors
- Dennis A. Johnson (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Plant Pathology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525060101842
- Language
- English
- Resource Type
- Thesis