Evaluation of common bean genotypes against root rot complex pathogens in West Hararghe, Eastern Ethiopia

Common bean root rot caused by different fungal pathogens is an important disease affecting common bean (Phaseolus vulgaris L.) production and productivity. In Ethiopia, this disease has become one of the most destructive biotic constraints to common bean production. Information on common bean root rot disease management is lacking for the Ethiopian common bean production system in general and West Hararghe in particular. Therefore, in the 2018 main cropping season, a field experiment was performed on 19 common bean varieties in two research fields, the ‘Bareda and Oda Baso’ farmers’ training centers. The experiment was designed to evaluate the level of resistance of a common bean genotype against root rot complex pathogens under natural conditions using a Randomized Complete Block Design (RCBD) design with three replications. The levels of resistance were evaluated based on seedling emergence, disease incidence, and severity in parallel with grain yield data and subjected to analysis of variance (ANOVA). Based on the laboratory results, four pathogenic fungi, namely, Fusarium oxysporum f. sp. Phaseoli (F. o. f. sp. Phaseoli), Rhizoctonia solani (R. soni), Sclerotium rolfsii (S. rolfsii), and Macrophomina phaseolina (M. phaseolina), a Nematode sp., and stem maggot insect were identified. The combined analysis of variance showed very highly significant variation at (p < 0.0001) across the location. There was also very highly significant variation (p < 0.0001) among treatments except for seedling emergence, incidence, and severity, which were highly significant (p < 0.001). From the experiment, seven common bean varieties (Kufanzik, Roba, Hirna, SeR-125, Cranscope, Tinike, Awash-1) that showed resistance characteristics and two susceptible varieties (Choire and Argane) were selected and recommended.