Successful chickpea production in western Canada typically requires multiple applications of fungicides to minimize the severity of Ascochyta blight (AB) caused by <i>Ascochyta rabiei</i>. Although planting resistant cultivars could be economical and environmentally safer than fungicide usage, varieties with a high level of resistance are not available. The objectives of this research were i) to determine the effect of different seeding arrangement treatments on ascochyta blight severity and seed yield of two cultivars (moderately resistant and susceptible) of kabuli chickpea; ii) to compare one and four fungicide applications at recommended and reduced rates and their impact on disease severity and cost; and iii) to assess organ-specific reaction to AB in chickpea in leaves, stems and pods of 12 desi and 12 kabuli varieties that are of economic significance to western Canada. <p>Treatments significantly influenced AB severity on both moderately resistant and susceptible cultivars in a season with a severe epidemic. Seed yield was significantly influenced by treatments for both varieties in both years. Contrast analyses revealed that four fungicide applications significantly reduced the AB severity for both varieties in a season with a severe epidemic and for the susceptible variety in a season with a moderate epidemic. Seed yield of both varieties was significantly higher under four fungicide applications compared to a single application. Solid seeding and paired row arrangements did not differ in their effect on seed yield and AB severity for both varieties in both years, except that the susceptible variety benefited from paired row planting with respect to seed yield and reduced AB severity in the season with a severe epidemic. Reducing fungicide rates and seeding rate could reduce the cost of cultivation without significantly affecting disease control and yield. Economic assessment revealed that in a severe epidemic season, the gross returns were high for the moderately resistant variety under four fungicide applications than one fungicide application. Gross returns for the susceptible variety were higher under four fungicide applications in both years.<p>There were differences among varieties for AB severity on leaves, stems and pods, seed yield and 1000 seed weight at all site-years tested. The variation was greater in kabuli varieties than desi varieties. AB severity on leaves, stems and pods was lower under high fungicide regimes, with few exceptions. Varieties with a fern leaf type had lower AB severity than those with unifoliate leaves. There was a positive correlation among AB severity on leaves, stems and pods. No differences in organ-specific reaction were observed.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-06062007-194226 |
| Date | 08 June 2007 |
| Creators | Chandirasekaran, Rajamohan |
| Contributors | Shirtliffe, Steven J., Gan, Yantai, Coulman, Bruce E., Banniza, Sabine, Warkentin, Tom D. |
| 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-06062007-194226/ |
| 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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