45 Our Advertisers Appreciate Your Business Better Farming | September 2024 Blackleg race testing Blackleg race testing has been on the market for several years. It goes beyond indicating the presence of the disease and instead gives an exact race breakdown of the sample. There are several labs across the Prairies that now do race testing. Each of them has their own set of lab protocols and sampling instructions that should be followed closely when collecting samples. A list of labs can be found at blackleg.ca. Keep in mind that your results are only as valuable as the sample sent in. Always follow the specific lab instructions and confirm with them if you have any questions. Interpreting blackleg race test results You sent off your sample and have received the results. Now what? On each sample you will receive a result that shows a genotype and a phenotype of the race of blackleg pathogen. The genotype reflects a much more complicated relationship between Avr genes and Rlm genes. For our purposes we just focus on the phenotype. The phenotype lists the Avr genes detected within the blackleg race in your field. Each Avr gene will match up with a major gene (Rlm). From there you need to choose a corresponding resistance group based on the major gene to narrow down the right cultivar choice for the field. For example: Phenotype: AvrLm2-4-5-6-7-11 Above we see six Avr genes within the blackleg race detected in the field. Using the table in Figure 2, we can choose corresponding major genes to our Avr genes. In the case above, we have Avr 2, 4, 5, 6, 7, and 11 which means a cultivar with one of the following major genes would work: Rlm 2, Rlm 4, Rlm 5, Rlm 6, Rlm 7, or Rlm 11. Currently only Rlm 2, 4, and 7 have cultivars on the market. As long as our cultivar matches a single Avr gene in the blackleg race present, it will be able to recognize the disease and trigger a response. Due to this, we could use any cultivars with the following resistance groups: RG B (corresponds with Rlm2), RG E1 (corresponds with Rlm4) or RG Ag Insights PLANT the WAVE Maizex offers high-performance corn and soybean seed developed for Canadian farmers by a company owned by Canadian farmers. Contact your local Maizex representative today. FIELD by FIELD | maizex.com Ride the wave to higher yields. Maizex_BF Prairies_Plant_3.375X10_7_30_24.indd 1 7/30/24 3:44 PM A diagram showing the defence response from a canola cultivar when its major gene corresponds with the avirulence genes in a blackleg race. Canola Council of Canada photo
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