Fungi contribute to key processes in the sustainable function of terrestrial ecosystems including nutrient cycling and transport of water to plants. However, some fungal species are of interest because their infection of a susceptible host crop results in diseases negatively affecting food supply and quality. These diseases are expected to be influenced by rotation crops which could impact the development of plant pathogens and their genetic biodiversity. The objectives of this study were to assess the biodiversity of fungal pathogens in durum wheat, to identify the naturally occurring fungi that could have biocontrol potential, and to define the impact of crop rotation with non-cereal crops on fungal populations in durum wheat. For this purpose, in 2004, 2005, and 2006, soil and durum wheat plant samples were collected after preceding crops of <i>Pisum sativum</i> L. (pea), <i>Lens culinaris</i> Medik (lentil), <i>Cicer arietinum</i> L. (chickpea), <i>Brassica napus</i> L. (canola) and <i>Triticum turgidum</i> L. (durum) in a long term experimental site in Swift Current, Sakatchewan. Samples were analyzed using a combination of traditional cultivation techniques and polymerase chain reaction (PCR), sequencing, and denaturing gradient gel electrophoresis (DGGE) techniques. <p>Fusarium species, known as the causal agent of Fusarium head blight (FHB) and Fusarium damaged kernels (FDK) were among the most ubiquitous and abundant in durum tissues. The most prevalent of all Fusarium at the study site were <i>F. avenaceum, F. reticulatum</i>, and <i>F. tricinctum</i>. Other recovered potential fungal pathogens belonged to the genera Bipolaris, Phaeosphaeria, Pyrenophora, Cladosporium, Epicoccum, Alternaria, Cladosporium, Arthrinium, Nigrospora, and Microdochium. Principal component analysis revealed negative correlations between Acremonium, Chaetomium, Penicillium, and pathogenic Fusarium, Bipolaris, Pyrenophora, and Alternaria. These isolates could be antagonistic, and their potential as biocontrol agents against pathogens colonizing durum wheat in the semiarid Saskatchewan should be assessed.<p>Crop rotation had a limited impact on the abundance of fungal pathogens. Fusarium torulosum was less abundant in durum following canola while Bipolaris sorokiniana was less abundant in durum following pea. Even if no single crop rotation reduced significantly the prevalence of F. avenaceum in durum wheat, results suggest that a successful control of this important pathogen requires an integrated approach using diversified rotations.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-07212008-143535 |
| Date | 23 July 2008 |
| Creators | Mavragani, Delia Crina |
| Contributors | Qiu, Xiao, Korber, Darren R., Kaminskyj, Susan G. W., Chantal, Hamel, Vujanovic, Vladimir |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-07212008-143535/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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