Assessment of losses in yield and yield components of rice in relation to different severity levels of brown spot

摘要

Correlation coefficients between yield components and different severity levels of brown spot, caused by Helminthosporium oryzae, indicated that grain weight panicle~(-1) (r = -0.991) and number of filled grains panicle~(-1) (r = -0.980) decreased andnumber of unfilled grains panicle~(-1) (r= 0.986) increased significantly with an increase in the disease severity level. However, correlation between disease severity and number of total grains or discoloured grains panicle~(-1) was not significant. Further, correlation matrix of yield with yield components and multiple regression analysis showed that the reduction in grain yield was largely due to reduction in filled grains panicle~(-1).