Chitosan, a sensitizer for Sclerotium resistance in groundnut

摘要

The possibility of using chitosan, a polymer of b-1, 4-linked glucosamine as pre-sowing seed treatment of susceptible groundnut cv. J-ll against Sclerotium rolfsii Sacc. has been explored. Against heavy symptoms and high mortality in the untreated plants, those in chitosan treatments reduced disease index by 35-88% and plant mortality from 68% to 11-21%. In such effective treatments, the infected host tissue recorded marked reductions in specific galacturonase activity and moderate increases in calcium and magnesium levels, besides substantial increases in total and ortho-dihydroxyphenol contents and also enhanced polyphenoloxidase activity. Chitosan at 0.3 % showed better results in both respects.