Downy mildew on oilseed Brassicas — understanding the drivers of disease epidemics and potential of novel host resistances

This is the first research to demonstrating expression of pathotype-independent host resistances to the downy mildew pathogen Hyaloperonospora brassicae across an extensive set of canola varieties and diverse Brassicaceae. Highly resistant varieties were identified. Studies of the effect of temperature and plant age explain, for the first time, why the incidence and severity of downy mildew is most severe on seedlings and why both have increased as season temperatures increase as a consequence of climate change. The new set of Brassicaceae plant host differentials developed provides the first practical means for monitoring changes in pathotype structure within H. brassicae populations.