Evaluation of Rice Germplasm for Resistance against Pyricularia oryzae the Cause of Rice Leaf Blast

Rice blast caused by Pyricularia oryzae is one of the most important diseases in rice growing areas of the world. Fifty two rice genotypes including one susceptible check, Basmati C-622, were evaluated to find out new sources of resistance and assess their diversity based on the reactions against P. oryzae. The test genotypes were evaluated against leaf blast after three weeks of inoculation by following the standard evaluation system for rice introduced by the International Rice Research Institute, Philippines. Diversity of the 52 genotypes was also assessed based on blast symptoms. Moderately resistant reactions were observed with genotypes KSK-470, KSK-463, KSK-460, PK 8685-5-1-1-1, KSK-462, KSK-474, PK 3810-30-1, KSK-471 and KSK-472. The 52 genotypes were grouped in 4 clusters. The grouping of some genotypes in same cluster is based on their similar reaction against leaf blast. The results of this study can be useful for selecting suitable genotypes for the development of blast-resistant rice varieties through hybridization.