Dissertation
INFECTIVITY OF VERTICILLIUM DAHLIAE ISOLATES ON WEEDY HOSTS, LITCHI TOMATO, AND TEFF, AND THE EFFECT OF ALFALFA RESIDUE INCORPORATION ON THE NUMBER OF VERTICILLIUM DAHLIAE MICROSCLEROTIA, AND SOIL BACTERIAL METAGENOMICS
Doctor of Philosophy (PhD), Washington State University
01/2017
Handle:
https://hdl.handle.net/2376/12953
Abstract
Verticillium wilt, caused by <i> Verticillium dahliae </i>, is an important disease of many dicotyledonous crops due to a wide host range and the long-term survival of microsclerotia in soil for up to 14 years. Some <i> V. dahliae </i> isolates are aggressive on a specific plant host, such as potato, but can still infect a range of crops. Isolates of <i> V. dahliae </i> that are aggressive on potato are referred to as the potato pathotype. Litchi tomato (<i>Solanum sisymbriifolium</i>) has been grown as a trap crop for the pale cyst nematode in Idaho and teff (<i>Eragrostis tef</i>) could be a short-season rotation crop in the northwestern United States. It is unknown if litchi tomato, teff, or weeds could serve as sources of inoculum for the potato pathotype of <i> V. dahliae </i>. When sixteen weeds were evaluated for <i> V. dahliae </i>, black nightshade (<i>Solanum nigrum</i>) had significantly more microsclerotia of the <i> V. dahliae </i> potato pathotype compared to the other isolates in three of four greenhouse trials (second trial <i> P </i> 0.0158, third trial <i> P </i> < 0.0264, fourth trial <i> P </i> < 0.0193). There were no differences in numbers of microsclerotia between isolates of <i> V. dahliae </i> in infected teff, while on litchi tomato the potato pathotype of <i> V. dahliae </i> produced greater numbers of microsclerotia than other isolates in one of six trials (first trial FDR-adjusted <i> P </i> < 0.0149). Soil incorporation of alfalfa residues prior to planting potato could be a Verticillium wilt management strategy by reducing the number of viable microsclerotia in field soil. The impact of incorporating alfalfa residue on soil metagenomics is unknown. The number of <i> V. dahliae </i> microsclerotia in soil where alfalfa was incorporated was greater than when residue was not incorporated (<i> P </i> = 0.0003) when field soils were subject to soil fumigation with chloropicrin. The soil bacterial metagenome in field soils subjected to alfalfa residue incorporation did not differ from those not subject to residue incorporation after one year. Alfalfa residue incorporation alone did not reduce <i> V. dahliae </i> microsclerotia in the soil or impact soil metagenomics; the practice by itself was not an effective strategy to induce a disease-suppressive soil on short rotations.
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Details
- Title
- INFECTIVITY OF VERTICILLIUM DAHLIAE ISOLATES ON WEEDY HOSTS, LITCHI TOMATO, AND TEFF, AND THE EFFECT OF ALFALFA RESIDUE INCORPORATION ON THE NUMBER OF VERTICILLIUM DAHLIAE MICROSCLEROTIA, AND SOIL BACTERIAL METAGENOMICS
- Creators
- Zachary Andrew Frederick
- Contributors
- Dennis A Johnson (Advisor)Debra A Inglis (Committee Member)Weidong Chen (Committee Member)Mark J Pavek (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Plant Pathology
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 180
- Identifiers
- 99900581828601842
- Language
- English
- Resource Type
- Dissertation