Disease Resistance
The availability of disease resistance traits through leading genetic packages is an important tool in managing canola
rotations for long term sustainability of the crop. Blackleg, sclerotinia and, more recently, clubroot have become high
priority issues when selecting a canola hybrid.
Blackleg
Blackleg resistance has been available in commercial varieties since the early 1990s. However, in recent years, the
virulence of the blackleg fungus has been shifting, resulting in the breakdown of resistance in many traditional canola
varieties. Multigenic resistance, which is available in all canola varieties sold in Western Canada, is a combination of
qualitative and quantitative genes and is the best and most durable form of blackleg resistance. Nutrien Ag Solutions
plant breeders are constantly testing and incorporating the most effective genes into Proven Seed canola hybrids.
Sclerotinia
The recent introduction of varieties with some physiological tolerance to sclerotinia is another management tool
for growers. These varieties have demonstrated a significant ability to reduce sclerotinia severity in the field and
protect yield in years with average disease pressure, although a fungicide application may still be warranted depending
on the conditions.
Clubroot
Clubroot is quickly spreading across the Prairies. Nutrien Ag Solutions is proud to offer clubroot-resistant canola
varieties that carry genetics which result in a reduction of disease to less than 30 per cent of a fully susceptible
variety. Resistance does not mean that the variety is immune to the disease and some galls may still be produced
if the disease is present in the field. Single-gene resistant varieties, which are effective against the predominant
strains, can be grown in areas with low levels or no clubroot to keep spore levels low. These varieties should not
be grown repeatedly in a short rotation as it increases the speed of which a shift towards a more virulent strain
will occur. Two-gene resistant varieties, which have more than one resistance gene, offer additional protection,
reduce selection pressure and enable resistance to remain durable for longer. These varieties are an excellent tool
to rotate genetics where current clubroot hybrids are still effective but the risk of becoming susceptible is still high.
VARIETY BLACKLEG CLUBROOT SCLEROTINIA
PV 200 CL R S S
PV 531 G R S S
PV 540 G R S S
PV 560 GM R S S
PV 581 GC R Single-gene S
PV 585 GC R Two-gene S
PV 591 GCS R Single-gene T
R= Resistant T = Tolerant S = Susceptible
LPC Summary
• Hybrids with lower standability ratings are
typically easier and faster to swath. This can
lead to time savings in the field, and the ability
to manage acres more effectively and efficiently.
• Environmental factors cannot be controlled, only
managed. Seeding a variety of high-yielding hybrids
increases the likelihood of attaining optimum returns.
Disease resistance and tolerance is one tool in a sound
canola disease management system; rotations and
field hygiene best practices are others.
• Yield potential can be maximized by selecting the
right hybrids for the farm based on genetic potential,
standability, days to flower and maturity.
4