Journal of Plant Studies; Vol. 8, No. 1; 2019 ISSN 1927-0461 E-ISSN 1927-047X Published by Canadian Center of Science and Education 30 Screening Common Bean (Phaseolus vulgaris L.) Germplasm for Resistance against Angular Leaf Spot (Pseudocercospora griseola) Disease under Field Condition Yayis Rezene 1 & Shiferw Mekonin 1 1 Southern Agricultural Research Institute (SARI), P.O. Box 06 Awassa, Ethiopia Correspondence: Southern Agricultural Research Institute (SARI), P.O. Box 06 Awassa, Ethiopia. E-mail: rezene77@gmail.com Received: December 26, 2018 Accepted: January 11, 2019 Online Published: February 12, 2019 doi:10.5539/jps.v8n1p30 URL: https://doi.org/10.5539/jps.v8n1p30 Abstract Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola is one of the most destructive disease in Latin America and eastern Africa countries. The fungus, P. griseola is highly variable and a diverse sources of resistance genes is required to manage this economically important disease. The use of genetic resistance is the most practical and economic way to manage angular leaf spot of the common bean. Common bean (Phaseolus vulgarise L.) germplasm were screened for resistance against Angular leaf spot (ALS) under field conditions at Wonodogenet and Areka Research farms. Out of 300 common bean accessions evaluated only 14 (4.6%) common bean accessions were resistant to naturally epidemics of angular leaf spot disease under field condition. Therefore, all common bean germplasm that showed resistance reaction can be involved in breeding program for the improvement of the common bean. Keywords: screening, angular leaf spot disease, disease reactions 1. Introduction Common bean (Phaseolus vagaries L.) one of the most important pulse crop in terms of nutrition, food security and economy, is cultivated in different regions of Ethiopia (Lemessa and Tessfaye, 2005). Among the most cause of poor yield in common bean production includes fungal, bacterial and viral diseases (Ferreira et al., 2003; Rezene et al., 2018). Angular leaf spot caused by Pseudocercospora griseola, may induce up to 40 to 80% yield loss when a susceptible variety is grown in a region with cool to moderate temperatures (13-26 0 C) and abundant moisture (Lemessa et al., 2011). Several strategies can be used to manage angular leaf spot but the use of genetically resistant common bean cultivars is the most effective controlling measures farmers to adopt (Pastor-Corrales et al., 1998; Schwartz et al., 1999; Wagara et al., 2003). The main drawback to resistant cultivars is the possible breakdown of the resistance caused by adaptation of the pathogen to host resistance (Guzman et al., 1979; McDermott et al., 1993). A number of exotic sources of ALS resistance do exist and have been utilized in breeding programs targeting ALS and the cultivars with sources of resistant includes Mexico 54, MAR1, MAR2, AND277, G5686, G10909 and G10474 (Mahuku et al., 2003; Caixeta et al., 2005). Besides, majority of resistance sources are with a climbing growth pattern; such attributes are not readily accepted by farmers in Africa at large (Beebe et al., 1981) and specifically in Ethiopia. But landraces and introductions with bush type growth habit adapted and maintained by farmers have for a long time been known to have useful agronomic traits. Indeed, most existing resistant sources developed elsewhere, have been derived from landraces (Busogoro et al., 1999). For instance, G5686, which is a good source of ALS resistance and a member of the ALS differential set, is a landrace that originated from Ecuador (Mahuku et al., 2009). Though resistance may exist in bean collections, the high degree of genetic variability of P. griseola often compromises the use of ALS resistance derived from landraces (Nietsche et al., 2001). This is due to continuous emergency of new races, which break down disease resistance (Young et al., 1998). Hence, the need for continuous screening of germplasm to identify new sources of resistance that can regularly be introgressed into commercial cultivars (Young & Kelly, 1996). This will counteract the new emerging races and reinforce resistance in existing ALS resistant sources. Therefore, this screening study was conducted to asses and identify resistant common bean accessions to be used