The protocol developed in this project could be a new tool for blackleg resistance breeding, and a new standard for labelling the QR trait of canola cultivars against blackleg.
This study explores a protocol to measure quantitative resistance (QR) to blackleg in canola under controlled environment and field conditions.
QR or adult plant resistance is important to sustainable blackleg management in Canada. Blackleg resistance labelling is readily applicable for major-gene resistance but not yet possible for QR. This project will develop and validate a system to rate quantitative resistance (QR) against blackleg under both controlled environment and field conditions.
Once developed and validated, the method will be used to quantify QR in canola cultivars and help screen QR traits in commercial canola breeding lines.
More than 50 canola hybrids/inbred lines with varied blackleg resistance in multi-year field trials were gathered from seed companies. Initial experiments identified a relationship between the level of QR and the amount of pathogen DNA detected in infected canola tissues. This relationship was validated using petiole and cotyledon inoculations under greenhouse and field conditions.
DNA analysis using droplet digital PCR (ddPCR) can identify strong QR in breeding lines for development of canola hybrids with good QR background against blackleg. It could be a new tool for blackleg resistance breeding, and a new standard for labelling the QR trait of canola cultivars against blackleg.