Screening of Common Bean Genotypes for Their Resistance to Bean Stem Maggot (Ophiomyia Spp.) in Ethiopia

Abstract

Common bean production in Africa faces various constraints, including biotic and abiotic stress. Among biotic stresses, bean stem maggots (BSM) (Ophiomyia spp.) are the most damaging insect pests of common beans in central and sub-Saharan Africa, especially under poor soils and dry conditions. Various control measures are available for bean stem maggots; however, there is insufficient information regarding the resistance of common bean genotypes to this pest. The present study aimed to identify sources of resistance to BSM in two groups of genotypes, namely red mottled and sugar bean, at Negelle Arsi and Shalla in Ethiopia during 2016 and 2017. A total of 111 genotypes with 56 belonging to the red mottled group and 55 to the sugar bean group were assessed for their resistance levels in open fields with a history of BSM infestation following randomized complete block design with three replications. In the 2016 assessment, 23 genotypes exhibited significantly lower numbers of dead seedlings and damage scores in both bean groups and locations. The results for the second year (2017) indicated that four genotypes from the red mottled group (DAB-365, DAB-398, DAB-449, and DAB-331) and four from sugar beans (DAB-500, DAB-512, DAB-483, and DAB-54) were moderately resistant to BSM in both locations. The combined findings from the 2016 and 2017 cropping seasons revealed that DAB-500, DAB-512, DAB-483, and DAB-541 from the red mottled group, and DAB-365, DAB-398, DAB-449, and DAB-331 from the sugar bean group, exhibited resistance to BSM at both locations. Therefore, based on the aforementioned information, these eight genotypes from both groups are recommended as potential sources of resistance to bean stem maggots for further common bean breeding purposes.