author(s)
Dalip Kumar, Dilbag Singh Ahlawat, Surender Singh Yadav, Lomash Kumar, Deepika Kalkal and Vivek Kumar Saini

abstract
Sugarcane genotypes selected on the basis of dead hearts formation were studied for biochemical based characters of resistance. Variations were recorded in the NDF and ADF contents of the shoots of low and high susceptibility across the stages of shoot development. However, in general, at 45 and 60 days after planting, the neutral and acid detergent fibres were higher in least susceptible genotypes than that of highly susceptible ones. At 45 DAP, the least susceptible variety CoS 767 showed 71.9 percent NDF and 42.8 percent ADF, while CoJ 64, the highly susceptible variety recorded 66.7 percent NDF and 37.6 percent ADF. Both, NDF and ADF showed a significant inverse relationship to borer susceptibility. At 60 DAP, the average NDF of least susceptible (70.8 percent) and moderately susceptible (68.2 percent) genotypes were more than that of highly susceptible genotypes (66.8 percent). There were considerable differences in the contents of cellulose, lignin and silica of spindle in 45 and 60 days old shoots of low, moderate and high susceptible genotypes. Higher levels of cellulose, lignin and silica were observed at 60 DAP than at 45 DAP with significant differences in contents of least, moderately and highly susceptible groups. Both, cellulose and lignin contents were found to be lower where the borer incidence was higher. Compared to cellulose; the lignin content showed a sharper contrast between entries of different susceptibility. The lignin contents ranged from 5.4 percent (CoJ 64) to 6.9 percent (CoS 767), while the cellulose content varied between 31.8 percent (CoJ 64) to 34.0 percent (CoS 767). All three biochemical constituents thus revealed a significant increase relationship with the incidence, with lignin being of a higher order (r = -0.861, 45 DAP) than cellulose (r = -0.746, 45 DAP) and silica (r = - 0.465).