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.”
A minimum two-year break between canola crops allows for the crop residue housing the blackleg-causing pathogen (Leptosphaeria maculans) to breakdown. Another way to manage blackleg is through the use of genetic resistance. Canola hybrids use two sources of resistance and it’s best to have a combination of major genes (qualitative resistance) and quantitative resistance within a hybrid.
Major gene resistance are single genes that are race-specific and highly effective at blocking infection of specific blackleg pathogen races at all growth stages. Major genes are identified and classified by resistance gene groups to help you select genes that are relevant to the pathogen causing blackleg damage.
Quantitative resistance involves many genes working together to slow the progression of the pathogen within the plant. This form of resistance is non-race-specific, providing protection towards 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. That 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.
| 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.
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.
