Assessment of Root Rot Pathogens of Common Bean (Phaseolus Vulgaris L.) and Reaction of Genotypes to the Pathogens in West Hararghe Zone, Ethiopia

Abstract

Common bean root rot caused by fungal pathogens is an important disease affecting common bean crops in Ethiopia. Information on pathogen identification, characterization, and management options is lacking for the Ethiopian bean production system. This study aimed to assess the major causal fungal pathogens and their management through host resistance methods. Initially, a field survey was conducted in three districts in 2016. It was cored forty-five (45) common bean fields. In the mean time, disease samples were collected for laboratory analyses. Secondly, pathogen identification and characterization were done in Laboratory at Haramaya University, followed by a pathogenicity test. Thirdly, a genotypic reaction was done on twenty common bean varieties by using four fungal genera (F. oxysporum, S. rolfsii, M. phaseolina, and R. solani) as experimental materials that were arranged in (CRD) design with three replications. Out of forty-five (45) common bean fields assessed 33 farms exhibited the disease. In the pathogenicity test, all the isolates were found pathogenic and showed a significant (p < 0.05) difference. In addition, the analysis of variance also showed that out of the tested twenty varieties, some released varieties (Dandesu, Tinike, SER-125, Dursitu, and Chorie), Chorie and (Dursitu, Chorie, Cranscope, Argene and SAB 632) showed highly significant at (p≤ 0.001) to Fusarium oxysporum f.sp. phaseoli, Sclerotium rolfsii, and Rhizoctonia solani while they didn’t exhibit any significant (p < 0.05) difference to Macrophomina phaseolina. In conclusion, those varieties showing resistance characters were recommended for growers.