Effects of clubroot-resistant canola lines on soil infested by Plasmodiophora brassicae

The Challenge

Due to its long-lived spores and its ability to rapidly multiply within a field, understanding the short- and long-term effects of clubroot-resistant canola lines at different infection levels is essential to maintain favourable and successful canola yields across the prairies.

The Project

Develop an integrated approach for mitigating clubroot on canola, focussing on reducing soil populations of P.brassicae.

• Determine the effect of spore loading on yield losses in canola
• Demonstrate the potential benefits and risks arising from use of resistant canola cultivars in infested soil
• Demonstrate how various crop rotations affect clubroot severity in a susceptible crop

The Results

• The susceptible cultivar resulted in greater soil spore populations, higher disease levels, more root hair infection, reduced plant height and seed yield compared to the resistant cultivar.
• At high inoculum densities in naturally infested soil dilutions, variations in inoculum density did not affect clubroot severity, but yield and seedling emergence declined as inoculum density increased.

Grower Benefits

With this research, growers now understand that if clubroot resistant varieties are not deployed soon enough within fields, the potential to build a high spore which can affect plant height, seedling emergence, and yield can be accomplished within one growing season of a susceptible variety.