dc.contributor.author	Rong, Lihua
dc.contributor.examiningcommittee	Duncan, Robert (University of Manitoba, Plant Science) Rashid, Khalid (Plant Science) Irvine, Byron (Agriculture and Agri-Food Canada, Brandon Research and Development Centre)	en_US
dc.contributor.supervisor	Fernando, W.G. Dilantha (Plant Science)	en_US
dc.date.accessioned	2018-01-10T16:07:08Z
dc.date.available	2018-01-10T16:07:08Z
dc.date.issued	2017
dc.degree.discipline	Plant Science	en_US
dc.degree.level	Master of Science (M.Sc.)	en_US
dc.description.abstract	Blackleg, caused by the fungal pathogen Leptosphaeria maculans (Desm.) Ces. & De Not, is an economically important disease in canola (Brassica napus L.) production. This study explored how temperature affects the Rlm gene- mediated resistance to L. maculans in canola. It also investigated the frequency of AvrLm genes and race structure of L. maculans in High Erucic Acid Rapeseed (HEAR) and canola fields in Manitoba, Canada. This study found that Rlm1, Rlm2, Rlm3 and Rlm4 in Topas isogenic lines (ILs) of B. napus are not sensitive to temperature, while Rlm3 in Quantum and Rlm4 in Falcon broke down at higher temperatures of 25/20 and 30/25 °C. The temperature had a significant effect on lesion size, where a higher temperature resulted in larger lesions in Topas ILs. Temperature also had a significant effect on L. maculans, where the optimum temperature was 25 °C for its growth and sporulation. Under different temperature treatments, different genotypes with the same Rlm genes responded differently to L. maculans. This may indicate that the genetic background is important in single Rlm gene-mediated resistance expression. This study also identified and examined 297 isolates of L. maculans from stubble collected in HEAR and canola fields in Manitoba in the 2013 and 2014 growing season. AvrLm6 and AvrLm5 were present in more than 90% of the population; AvrLm7, AvrLm4, AvrLm11, and AvrLm2 were present in more than 50% of isolates, while AvrLm3 and AvrLm9 had a very low frequency. In total, 85 races were identified, and AvrLm2-4-5-6-7-11 was identified in 14.8% of the population. AvrLm9 was not found in Manitoba in the 2014 growing season. The frequency of AvrLm genes and race structures varied over years, regions and cultivars.	en_US
dc.description.note	February 2018	en_US
dc.identifier.uri	http://hdl.handle.net/1993/32771
dc.language.iso	eng	en_US
dc.rights	open access	en_US
dc.subject	Temperature	en_US
dc.subject	Brassica napus	en_US
dc.subject	Leptosphaeria maculans	en_US
dc.subject	Race structure	en_US
dc.subject	Resistance	en_US
dc.subject	Blackleg	en_US
dc.subject	High erucic acid rapeseed	en_US
dc.title	Temperature effects on Brassica napus resistance to Leptosphaeria maculans and race structure survey of blackleg isolates in Manitoba	en_US
dc.type	master thesis	en_US
local.subject.manitoba	yes	en_US

Temperature effects on Brassica napus resistance to Leptosphaeria maculans and race structure survey of blackleg isolates in Manitoba

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