The inherent genetic similarity between oat (<i>Avena sativa</i> L.) and wild oat (<i>Avena fatua</i> L.) precludes selective herbicide use to control wild oat. Consequently, large reductions in oat yield and quality due to wild oat consistently constrain oat production in western Canada. Traditionally, delayed seeding followed by tillage prior to planting was used to control wild oat, but new studies have shown that this practice also results in substantial reductions to oat yield and quality. Thus, new methods are needed to ameliorate the adverse effects of wild oat competition on oat. Planting more competitive varieties with earlier emergence and larger seeds may minimize losses associated with wild oat competition. Therefore, the objectives of this research were i) to determine the influence of wild oat emerging at different times and varying densities on oat yield and quality and ii) to determine the relative importance of seed size and genotype in affecting wild oat oat competition. High densities of early emerging wild oat greatly reduced oat yield and increased wild oat contamination. Observed oat yield losses were as great as 70% and resulted in a 15% wild oat contamination level. Wild oat that emerged before oat also had higher biomass and reproductive output than wild oat that emerged after oat. Furthermore, early emerging wild oat reduced percentage plump oat kernels and increased percentage thin kernels. Oat plants established from large caryopses produced 18% more biomass and 15% more panicles m<sup>-2</sup> than plants established from small caryopses. In addition, wild oat produced 31% less biomass and fewer panicles m<sup>-2</sup> when grown with oat plants established from large caryopses. CDC Boyer appeared to be the most competitive of the varieties examined, having significantly higher biomass and panicle production both in the presence and absence of wild oat competition. Conclusions that emerge from this research are i) emergence time is critical to wild oat oat competition, ii) it is essential for oat producers to control early emerging wild oat and ensure crop emergence precedes wild oat emergence, iii) planting large seed of competitive cultivars may improve the competitive response of oat to wild oat.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-12212004-101918 |
| Date | 21 December 2004 |
| Creators | Willenborg, Christian James |
| Contributors | Shirtliffe, Steven J., Rossnagel, Brian G., Hughes, Geoffrey R., Ball, Rosalind A., Wolf, Thomas |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-12212004-101918/ |
| Rights | unrestricted, 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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