Lead Researcher | Gary Peng |
Co-Researcher(s) | Dilantha Fernando, Fengqun Yu, Sheau-Fang Hwang, Stephen Strelkov |
Start Date | April 2013 |
End Date | March 2017 |
Funding Partners | ACIDF, Manitoba Association of Agricultural Societies Inc., Manitoba Canola Growers, WGRF |
Status | Complete |
All commercially available cultivars rate as R or MR for blackleg, but severe blackleg infection (up to 100% disease incidence) has been found in fields across the prairies in 2012.
Identify new virulent races of L. maculans that are at high risk for overcoming specific R genes by monitoring pathogen race dynamics through yearly analysis of Avr gene prevalence.
AvrLm2, AvrLm4, AvrLm6 and AvrLm7 were found at high frequencies, while AvrLm1 and AvrLm3 were generally low. Rlm3 and Rlm1 are the more commonly R-genes found in Canadian cultivars, therefore other mechanisms may be influencing resistance such as quantitative and/or nonspecific race resistance.
By mapping the distribution of various blackleg races, better management strategies can be developed based on rotating resistant varieties carrying specific resistant genes. Caution should be used when recommending canola cultivar rotation based on specific R-genes as the pathogen can change substantially from one field to another. Where blackleg severity is high, longer crop rotation should be the first line of defence.
Keywords: Blackleg, Quantitative resistance, R genes, Resistance breakdown, Leptosphaeria maculans, L. maculans, Major gene resistance, Rlm3, Rlm1