Blackleg has been around for what seems like forever. The stubble-borne canola disease is most prevalent in Western Canada, its severity dependent on the environment and your management practices.
“The key to managing blackleg on your farm is through scouting fields prior to harvest,” said BrettYoung Agronomic & Regulatory Services Manager, Justine Cornelsen. “Assess the level of incidence and severity and develop an estimate of blackleg risk for future crops.”
Keys to Reducing Blackleg Risk
A minimum two-year break between canola crops allows for the crop residue housing the blackleg-causing pathogen (Leptosphaeria maculans) to break down. Another important management strategy is the use of genetic resistance. Canola hybrids use two primary sources of resistance, and ideally a hybrid will include both major gene (qualitative) and quantitative resistance.
Major gene resistance involves single genes that are race specific and highly effective at blocking infection from specific pathogen races throughout all growth stages. These genes are classified into resistance gene groups to help select those that best target the pathogen populations in your fields.
Quantitative resistance involves many genes working together to slow pathogen development within the plant. This type of resistance is non-race specific, offering broader protection across pathogen races.
Stewardship of Genetic Resistance
If your field has a high risk of blackleg infection due to intense canola rotations or it has known blackleg infections, you should consider rotating blackleg-resistant hybrids. This means selecting a canola hybrid with a different major gene group(s) than the previously grown hybrid. The blackleg race identification test is a great tool to use to determine what the predominant blackleg races are in your field and which major gene groups will be the most effective.
Blackleg stubble tests determine the L. maculans genotype and phenotype expressed in the field. The phenotype is used to determine which resistance gene groups will provide protection towards the L. maculans races identified.
Key Steps for Resistance Stewardship
- Rotate resistant hybrids: Select canola hybrids with different major gene groups when high risk is present.
- Use pathogen race tests: Employ blackleg race identification tests to match hybrids to field-specific threats.
- Analyze stubble tests: Interpret genotype and phenotype results to direct resistance decisions.
- Update hybrids regularly: Avoid repeatedly planting the same resistance group to slow pathogen adaptation.
- Reference resistance tables: Use available tables to choose effective gene groups for your fields.
| L. maculans phenotype | Major Resistance Genes | Resistance Gene Groups* | BrettYoung Hybrids to Utilize |
| AvrLm4-5-6-7-11 | Rlm4, Rlm5, Rlm6, Rlm7, Rlm11 | E1, E2 | BY 6217TF, BY 6216TF, BY 6204TF |
| AvrLm2-3-5-9-S | Rlm2, Rlm3, Rlm5, Rlm9, RlmS | C, F, G | BY 6214TF, BY 6211TF, BY 7102LL, BY 5125CL |
*Not all resistance genes are classified into resistance groups as they are not currently in Canadian canola germplasm
BrettYoung Blackleg DefendR® Hybrids
Growing a blackleg-resistant hybrid is your number one line of defence when it comes to managing this common disease. Our Blackleg DefendR® trait means the canola hybrid is rated as a strong R for blackleg resistance. It also means the hybrid incorporates multiple major genes to be completely resistant against specific races of the pathogen.
Blackleg DefendR hybrids achieve an enhanced level of resistance compared to competitors’ R-rated hybrids.
DefendR Hybrid Options
- BY 6217TF: Equipped with Blackleg DefendR for strong resistance and yield potential.
- BY 6216TF: Combines multiple major genes for broad-spectrum protection.
- BY 6214TF: Provides robust resistance and consistent crop performance.
- BY 6211TF: Suitable for diverse growing conditions, with superior disease defense.
- BY 6204TF: Delivers reliable resistance, even in high-risk blackleg environments.
- BY 7102LL: Includes Blackleg DefendR traits for maximum crop security.
If you’re looking to grow a blackleg-resistant canola hybrid, BrettYoung has lots of options. BY 6217TF, BY 6216TF, BY 6214TF, BY 6211TF, BY 6204TF and BY 7102LL all come equipped with Blackleg DefendR, ensuring your crop reaches its full potential regardless of the disease.
FAQ
What is blackleg and why is it important to manage?
Blackleg is a persistent stubble-borne disease that affects canola crops, especially in Western Canada. Managing it is important because it can damage crops and reduce yields.
How can scouting help reduce blackleg’s impact?
Scouting fields prior to harvest helps assess the incidence and severity of blackleg, allowing farmers to estimate future risk and plan effective management strategies.
What crop rotation practices help with blackleg management?
A minimum two-year break between canola crops allows the crop residue with the blackleg-causing pathogen to break down, reducing the risk of future infections.
How do genetic resistance and major genes help protect canola from blackleg?
Canola hybrids with genetic resistance combine major genes, which block specific pathogen races and quantitative resistance, which slows disease progression, offering comprehensive protection.
What are Blackleg DefendR hybrids and how do they differ from other hybrids?
Blackleg DefendR hybrids are BrettYoung canola hybrids that incorporate multiple major genes for strong blackleg resistance. They achieve enhanced resistance compared to competitors’ R-rated hybrids.
Why should farmers rotate blackleg-resistant hybrids?
Rotating blackleg-resistant hybrids with different major gene groups helps ensure ongoing protection because it targets the specific pathogen races present in the field.
Which BrettYoung canola hybrids include the Blackleg DefendR trait?
BY 6217TF, BY 6216TF, BY 6214TF, BY 6211TF, BY 6204TF and BY 7102LL all come with the Blackleg DefendR trait.
