Adult-plant resistance of upland rice genotypes against blast (Pyricularia oryzae Cavara) in Metekel Zone, North West Ethiopia

Rice blast disease, caused by Pyricularia oryzae Cavara is one of the main biotic factors and the most destructive of all rice diseases impeding rice production in more than 85 countries in the world. Among disease management methods, the use of host resistance is thought to be the most effective and economical for farmers to manage most of rice diseases. Successful resistance breeding program depends on the diversity of a crop with resistance genes. However, in Ethiopia, rice genotypes have not been examined in detail for their sources of resistance against rice blast disease. The present study was aimed to identify upland rice genotypes having resistance to rice blast at adult stage. A total of 36 upland rice genotypes including two checks were evaluated for their reaction to leaf and panicle blast at adult stage at Pawe Agricultural Research Center (PARC) of the Ethiopian Institute of Agricultural Research (EIAR) for two seasons during 2020 and 2021 cropping seasons. The treatments were arranged in simple lattice design (SLD). Of the 36 genotypes used in this study, none was immune and resistant to leaf and panicle blast. G9 and G20 have shown moderately resistant reaction against to leaf and panicle blast while most (61.11%) and (72.22%) of the genotypes showed moderately susceptible (MS) response to infection by leaf and panicle blast, respectively. However, 19.44% genotypes showed susceptible (S) to leaf blast and 16.66% to panicle blast. Agglomerative hierarchical clustering method of cluster analysis had grouped 36 upland rice genotypes into three classes based on the genotypes mean values for four disease traits over two seasons. In conclusion, the present investigation suggested that the majority of the tested rice genotypes were moderately susceptible against blast. However, G9 and G20 were showed moderately resistant reaction to leaf and panicle blast and can be utilized as a source of resistance in breeding program against blast of upland rice. Advanced study should consider evaluation of larger materials against the pathogen in greenhouse condition.