Abstract: The allelopathy and major allelochemicals in root exudates of hot pepper were studied by bioassay and GC-MS methods. The results showed that different components of root exudates of hot pepper had different allelopathy on lettuce. The allelopathy of aether soluble component was the highest, which was further separated and analyzed, and we found that 80％aether+20％ethyl acetate component held the highest allelopathy. Finally, the component of 80％aether+20％ethyl acetate was analyzed by GC-MS, and the main allelochemicals were identified as dibutyl phthalate, 1,2-benzenedicarboxylic acid, butyl cyclohexyl ester, 1,2-benzenedicarboxylic acid, butyl 2-methylpropyl ester, 1,2-benzenedicarboxylic acid, bis(2-methylpropyl) ester, diphenylamine, 4,4'-(1-methylethylidene)bis-phenol, 1-naphthalenamine, n-phenyl-, 1,2-benzenedicarboxylic acid, among which dibutyl phthalate held the highest level of chemical content.

Key words: hot pepper, root exudates, allelopathy, allelochemicals, lettuce