Herbicide tolerant canola volunteers in roadside habitats in southern Manitoba.
Knispel, Alexis*,1, McLachlan, Stéphane1, 1 Department of Environment and Geography, Winnipeg, Manitoba, Canada
ABSTRACT- In 2004, farmers in the prairie provinces produced 98.7% of the total Canadian harvested acreage of canola, almost 80% of which was transgenic herbicide tolerant (HT) canola. Concurrently, canola is the most prevalent in-field volunteer in Western Canada, and is a prominent naturalized species of roadsides, where its presence may facilitate the movement of seed and pollen into adjacent fields. In 2004, we examined canola populations occurring in roadside ditches in southern Manitoba. Our objectives were to determine the importance of herbicide tolerant (HT) varieties of canola occurring in roadside habitats, and to assess the potential for persistence of these populations. Eight roadside canola populations were identified and sampled in two regions in southern Manitoba. Within each population, ten reproductive plants were collected and their offspring tested for herbicide resistance. Species composition and canola presence and reproductive output were also recorded. Canola tended to occur in blinking populations with high individual turnover, though most populations survived the entire growing season and produced viable seed. All populations produced HT offspring. On average, 75% of sampled plants produced offspring resistant to glyphosate, and 20% of plants produced offspring which were resistant to both glyphosate and glufosinate. The large-scale release of HT canola in Canada, coupled with the high incidence of volunteers, poses challenges to the successful co-existence of conventional and HT varieties of this crop. Roadsides and other semi-natural habitats appear to play an important role in the movement of HT canola in agricultural landscapes.×
Key words: canola, volunteer, herbicide tolerant, roadside habitat
All materials copyright The Ecological Society of America (ESA), and may not be used without written permission.