Resistance sources to common bacterial blight and angular leaf spot of large speckled common bean genotypes in Southern Ethiopia

Abstract The common bean ( Phaseolus vulgaris L.) is one of the most important legume crops in Ethiopia due to its versatility and adaptability. The common bean is significantly affected by major diseases, including common bean bacterial blight and angular leaf spot. The present study was conducted, aiming at the identification of source resistance to common bacterial blight and angular leaf spot in the field condition. The experiment field was conducted at Adola, a research site in Southern Ethiopia, during the 2022 and 2024 main cropping seasons. The study was evaluating 76 advanced lines alongside checks over two consecutive years. The data analysis used multiple disease assessment parameters (final percentage of severity index and area under disease progression curve), multivariate analyses (principal component analysis, cluster analysis, and resistance mapping), and agronomic traits evaluation. Analysis of disease variables such as final percentage of severity index, area under disease progression curve, and other agronomic parameters showed that there were highly significant differences among common bean genotypes. Principal component analysis, cluster analysis, resistance map, and correlation of genotypes were well performed and showed significant variation of resistance reaction in genotypes during both years. Multimodal analysis showed that 32 (42.6%) of the common bean genotypes demonstrated moderate resistance and resistance reactions. Among those genotypes, G2, G20, G24, and G120 were shown as having resistant reaction to both angular leaf spot and common bacterial blight. These useful common bean genotypes could be promoted to breeding programs and released after their evaluation by breeders.