Evaluation of common bacterial blight resistance in a resistant inter-cross population of common bean




Durham, Kelli M.

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University of Guelph


Common bacterial blight CBB, caused by Xanthomonas axonopodis pv. phaseoli, is an important disease of common bean (Phaseolus vulgaris L.). Genetic resistance is the most economically-efficient, environmentally-friendly, and socially-acceptable approach to control plant diseases including CBB. To examine the main and interaction effects of the previously-identified CBB-resistance quantitative trait loci (QTL), a resistant inter-cross population of OAC Rex and HR45 was evaluated under artificial inoculation. While the QTL on chromosome B6 of HR45 accounted for 37 to 46 % of phenotypic variation in the field, the QTL on chromosome B4 of OAC Rex was only significant in more sensitive assays using image analysis under controlled condition using a select number of lines, accounting for 15% of the variation. Broad sense heritability estimates of CBB resistance and the QTL associated with BC420 were high for severity and the area under disease progress curve, promoting the continued use of this marker in selecting CBB resistant genotypes, which in combination with SU91 marker on B8 seem to provide high levels of resistance.



CBB, Image analysis, AUDPC, Phaseolus vulgaris, Visual screening, QTL, Resistance, Xanthomonas