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dc.contributor.supervisorMcLachlan, Stephane (Environment and Geography)en
dc.contributor.authorKnispel, Alexis L.
dc.date.accessioned2010-09-22T16:11:23Z
dc.date.available2010-09-22T16:11:23Z
dc.date.issued2010-09-22T16:11:23Z
dc.identifier.citationKnispel, A.L., McLachlan, S.M., Van Acker, R.C. & Friesen, L.F. (2008) Gene flow and multiple herbicide resistance in escaped canola populations. Weed Science, 56: 72-80en
dc.identifier.citationKnispel, A.L. & McLachlan, S.M. (2010) Landscape-scale distribution and persistence of genetically modified oilseed rape (Brassica napus) in Manitoba, Canada. Environmental Science and Pollution Research, 17: 13-25en
dc.identifier.urihttp://hdl.handle.net/1993/4224
dc.description.abstractGenetically modified (GM) canola (Brassica napus L.) has been widely adopted in Canada since its commercial release in 1995 and now represents over 85% of the canola grown in western Canada. Concurrently, GM canola volunteers have become an increasing management problem in cultivated fields and are ubiquitous in adjacent ruderal (non-cropped disturbed) habitats. However, systematic post-release monitoring is lacking and the ecological and agronomic impacts of escaped GM canola are poorly understood. In this dissertation, I characterize the escape, demography and distribution of GM canola in ruderal habitats in southern Manitoba, at multiple spatial and temporal scales. I characterized GM herbicide tolerance traits in 16 escaped canola populations. The progeny of 129 plants were tested in herbicide trials; 74% of plants produced glyphosate-tolerant progeny, 63% produced glufosinate-tolerant progeny, and 34% produced multiple herbicide-tolerant progeny as a result of gene flow between escaped plants. At the population-scale, four escaped GM canola populations were monitored and periodic matrix models were constructed to describe the dynamics and persistence of flowering plants. Escaped populations were observed to flower in synchrony with adjacent crops and were projected to persist for 2 to 5 years, confirming the potential for gene flow between escaped and cultivated canola populations. At the landscape-scale, the distribution of escaped canola was surveyed in three agricultural regions. Regional factors were important determinants of distribution; escaped canola density was positively correlated with canola cropping intensity and with traffic intensity, and was negatively correlated with distance to grain distribution centres. Local seed dispersal had negligible impact on distribution compared to landscape-scale anthropogenic seed inputs resulting from agricultural transport. These findings suggest that escaped canola persists as a metapopulation, where long-distance dispersal and colonization compensate for frequent extinction of local populations. Escaped populations play an important role in the persistence and spread of GM traits at large spatial scales, with substantial implications for the coexistence of GM and non-GM crops, and especially for organic and reduced-tillage farming operations. Landscape-scale management approaches, designed and implemented collaboratively by multiple stakeholders, are necessary to mitigate the risks of contamination resulting from GM trait escape. Regulation and ongoing monitoring of GM crops must acknowledge and address the dynamic regional nature of seed- and pollen-mediated gene flow.en
dc.format.extent1878689 bytes
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.rightsinfo:eu-repo/semantics/openAccess
dc.subjectGM cropen
dc.subjectgene flowen
dc.subjectherbicide toleranceen
dc.subjecttransgene spreaden
dc.subjectmetapopulationen
dc.titlePost-release monitoring of genetically modified canola (Brassica napus L.) in western Canada: escape, persistence and spread of novel traitsen
dc.typeinfo:eu-repo/semantics/doctoralThesis
dc.typedoctoral thesisen_US
dc.degree.disciplineEnvironment and Geographyen_US
dc.contributor.examiningcommitteeWalker, David (Environment and Geography) Van Acker, Rene (University of Guelph) Beckie, Hugh (Agriculture and Agri-Food Canada)en
dc.degree.levelDoctor of Philosophy (Ph.D.)en_US
dc.description.noteOctober 2010en


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