Response of Elite Dry Bean ( <i>Phaseolus vulgaris</i> ) Genotypes to <i>Fusarium oxysporum</i> and <i>Rhizoctonia solani</i> Root Rot

ABSTRACT Root rot is a major yield‐limiting disease of dry bean ( Phaseolus vulgaris ) production in the United States and worldwide. Specifically, disease symptoms conferred by the soil‐borne fungal pathogens Fusarium oxysporum and Rhizoctonia solani cause significant yield loss in susceptible dry bean cultivars through damage of root biomass, reduced vigour and plant death. This study was conducted in Michigan during 2021 and 2022 to evaluate field resistance to root rot conferred by these pathogens across a diverse set of breeding and diversity panel lines. Secondary objectives were to establish correlations between field and greenhouse trials and non‐destructive traits correlated to root rot resistance to F. oxysporum for ease of future high‐throughput phenotyping. All trials were successful in identifying significant variation for root rot resistance. Significant correlations were found between rankings in field and greenhouse trials (GH; p = 0.03, r = 0.71). Significant trait correlations were also identified between root rating and fresh ( p = 0.01, r = −0.67) and dry root ( p = 0.01, r = −0.64) and dry shoot ( p = 0.04, r = −0.43) biomass in the greenhouse. Ultimately, multiple lines with improved levels of resistance were identified as parents for future root rot resistance breeding efforts.