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Blackleg in canola seed and dockage: Can it cause plant infections?
D. FERNANDO (1), B. Demoz (1). (1) University of Manitoba, Winnipeg, MB, Canada

Blackleg disease caused by <i>Leptosphaeria maculans</i> is one of the major diseases of canola in the world. The pathogen can infect all parts of the plant but mainly causes girdling at the stem base causing subsequent yield loss. This study assessed the level of blackleg infection in seed and dockage, the type of spores produced by dockage, and ability of seed and dockage to cause infection in Canadian grown canola. Canola seed samples from different areas of the Prairie Provinces of Canada were tested for the presence of the aggressive <i>L. maculans</i> and the less aggressive <i>L. biglobosa</i>. One thousand seeds per sample were assessed using blot test. Isolates collected from each infected seed were identified with PCR using species-specific primers. The most frequently isolated species was <i>L. biglobosa</i> (4.04%) compared to <i>L. maculans</i> (0.24%). Infected seeds that germinated could not grow into adult plants; the cotyledons rotted. DNA was extracted from dockage and PCR tests showed the presence of <i>L. maculans</i> in dockage samples. Dockage samples incubated at different temperatures produced pycnidiospores but not ascospores. The ability of dockage to cause infection was tested by growing wounded cotyledons on flats covered with dockage pieces. Two weeks after wounding, infections marked by the presence of pycnidia were evident on cotyledons. Although <i>L. maculans</i> can be found in seeds, it is present at very low levels. Dockage could produce pycnidiospores and cause infection on cotyledons.<p><p>Keywords: Fungus

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