Stemphylium blight of lentil caused by <i>Stemphylium botryosum</i> Wallr., is a serious problem in Bangladesh, northeast India and Nepal causing more than 60 % yield losses under epidemic conditions. The pathogen started to appear on lentil in Saskatchewan in recent years and is widely distributed throughout western Canada but it is not well understood. An investigation of inheritance of resistance to stemphylium blight was done in the lentil cross Barimasur-4 × CDC Milestone. In order to develop a reliable indoor screening technique for this inheritance study, a suitable isolate of <i>Stemphylium botryosum</i>, a suitable culture medium for inoculum production and an appropriate plant age for indoor inoculation were identified. The maximum differential of disease severity was observed when lentil genotypes were inoculated at 14 days after planting (DAP). At 14 DAP, lentil plants rapidly defoliated but were capable of regrowth which caused variability in scoring for disease reaction. Inoculation at 42 DAP, close to the flowering stage, was found to be better for consistently scoring disease reaction. V8P medium was most suitable for inducing conidia production. Based on ability to sporulate, the isolate SB-19 from Saskatchewan was identified as suitable for conducting genetic studies of resistance to stemphylium blight. It was compared to isolate SB-BAN from Bangladesh for aggressiveness on two lentil cultivars. The SB-BAN isolate was found to be more aggressive. A preliminary screening of local and exotic germplasm done with the two isolates revealed considerable variability for disease resistance. Resistance to <i>S. botryosum</i> appeared to be quantitatively inherited in the cross Barimasur-4 × CDC Milestone according to both field and indoor screenings. The results of this study also confirmed that Precoz, one of the parents of Barimasur-4, was resistant to <i>S. botryosum</i>.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-08072007-234748 |
| Date | 15 August 2007 |
| Creators | Kumar, Pramod |
| Contributors | Vandenberg, Albert |
| 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-08072007-234748/ |
| 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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