BIOCHEMICAL ANALYSIS OF RESISTANT AND SUSCEPTIBLE COTTON GENOTYPES AGAINST ALTERNARIA AND CORYNESPORA

Cotton leaf samples of 10 genotypes LAHB-1, L799, L 389, L770 and LPS 141 (resistant); L 1060, L 2551, L 2503, L 397 and L 2559 (susceptible) along with one control (Jaadoo BG II hybrid) against Alternaria and Corynespora were analyzed at flowering and boll development stages for the estimation of total phenols, total proteins, total sugars, reducing sugars, nonreducing sugars, chlorophyll and peroxidises. Results showed that all the biochemical parameters,except peroxidase enzyme, showed decreasing trend from flowering to boll development stage. There was significant reduction in phenols at flowering stage (16.23% to 53.30%) and at boll development stage (22.71% to 58.37%), total proteins at flowering stage(16.91% to 58.19%) and at boll development stage (9.51% to 51.43%), total sugars at flowering stage (15.71% to 51.32%) and at boll development stage (28.10% to 65.05%), reducing sugars at flowering stage (9.59% to 53.00%) and at boll development stage (35.56% to 69.93%), nonreducing sugars at flowering stage (18.38% to 49.53%) and at boll development stage (10.53% to 92.84%) and total chlorophyll at flowering stage (24.80% to 48.46%) and at boll development stage (9.19% to 32.86%). However, there was increase in peroxidase content at flowering stage (59.94% to 225.35%) and at boll development stage (38.79% to 138.79%) as the disease severity increased.