Investigating the conditions favoring verticillium stripe development and yield losses in canola

Key Result

This project is still in progress, but aims to examine the interactions between blackleg and verticillium stripe in field conditions, and to quantify the combined effects of the two diseases on canola at various growth stages, from seedling to seed set, under varying soil pH levels, and to generate a large collection of V. longisporum isolates from across the Prairies. This project will also screen canola lines and accessions for verticillium stripe resistance, and assess the effects of verticillium stripe seed infection rate on disease severity.

Project Summary

Verticillium stripe has recently been identified on the Canadian Prairies, first in Manitoba in 2014, then in Saskatchewan and finally in Alberta, where many cases were confirmed across a wide area of the province in 2023. Verticillium longisporum is a difficult fungus to isolate and complicated to identify, and more research is needed to manage its spread. Verticillium stripe contributes significantly to yield losses in canola. In addition, preliminary reports documenting synergistic interactions between blackleg and verticillium stripe have surfaced.

Now is the time to gather the knowledge necessary to break synergistic interactions between L. maculans and V. longisporum before their combined impact leads to further losses in canola production. This project is designed to examine the interactions between these two pathogens in detail, as they occur in living plants and field conditions.

This research will study and quantify the combined effects of the two pathogens on the canola crop at various growth stages, from seedling to seed set, examine the dynamics of the interaction under varying soil pH levels, and generate a large collection of V. longisporum isolates from across the Prairies.

A practical model will be developed to relate verticillium and blackleg infection levels to yield losses in the field. The project will also screen canola lines for resistance to verticillium, examine the effects of canola defense mechanisms for one pathogen on its reaction to the second pathogen, and determine the range of host specificity among the V. longisporum isolates collected.

Genetic markers associated with resistance to verticillium stripe will be identified. While seedborne transmission of blackleg is well-established, more research is needed to determine the potential for seedborne transmission of V. longisporum, including the evaluation of seed sanitation and treatment strategies to reduce or eliminate this possibility.

This project addresses the management of these two diseases that have the potential to develop a synergistic relationship and cause further crop damage than either on its own.