SCREENING OF DIFFERENT WHEAT GENOTYPES AGAINST BIPOLARIS LEAF BLIGHT

Abstract

A total of 89 wheat genotypes were screened against Bipolaris leaf blight caused by Bipolaris sorokiniana under field condition. The experiment was conducted at Wheat Research Center Nashipur, Dinajpur during 2007-2008 crop seasons. Disease severity was rated three times as percent leaf area diseased (%LAD) on flag and flag-1 leaves of main tillers under three different dates of sowing. Percent disease index (PDI) and area under disease progress curve (AUDPC) were calculated using standard formulae. The genotypes were graded for their reactions into different resistance groups based on the final disease ratings on flag leaves averaged over three dates of sowing. Result shows that out of 89 genotypes screened, 10 were moderately resistant, 56 moderately susceptible and 23 susceptible. But none of the genotypes were found highly resistant or highly susceptible. The moderately resistant genotypes showed relatively lower PDI and AUDPC values than those of the susceptible ones. Plant growth and yield varied significantly among the different lines and varieties tested.