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An examination of historical root rot nursery data for Ontario adapted dry bean cultivars

Larsen RJ¹, Wally OSD¹, Rupert T¹, Navabi A², Smith TH², Pauls, KP², and Park SJ¹

¹ Harrow Research and Development Centre, Agriculture and Agri-Food Canada, Harrow, ON N0R 1G0, Canada

² Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada (Contact: Jamie.larsen@canada.ca)

Root rot continues to be a concern for dry bean (Phaseolus vulgaris L.) growers in Ontario, as well as throughout Canada. A root rot nursery was created over 40 years ago at the Harrow Research and Development Centre through Fusarium sp. Inoculation of a sandy loam soil field prone to flooding. Since the nursery was established, dry beans have been grown continuously each year to maintain inoculum levels and evaluate dry bean cultivars for resistance to root rot. A non-continuous data set from white bean and large-seeded coloured bean root rot disease nurseries was compiled from data collected between 2009 and 2018. Cultivars associated with this dataset represent 29 years of dry bean breeding efforts. All data was made relative to several common cultivars that were present in each year of the trials to reduce the environmental variance component relating to disease scores. Results indicate that for all dry bean varieties evaluated there has been no significant genetic improvement to reduce root rot susceptibility. A trend towards reduced root rot symptoms in white bean cultivars was observed, but was not statistically significant. Genetic improvement for root rot resistance continues to be a challenge and a concerted effort using existing and new approaches should be employed to reduce the impact of root rot in dry beans.