Impact of allelochemicals from sorghum and sunflower on germination parameters of wheat and Phalaris minor

A laboratory experiment was conducted in seed physiology laboratory of Department of Agronomy, GBPUA&T, Pantnagar to evaluate the allelopathic potential of aqueous extracts of sorghum and sunflower on germinating seedlings of Phalaris minor and wheat. Sorghum and sunflower aqueous extracts were applied at the rate of 10% (w/v) on the seed of Phalaris minor and wheat and the parameters like germination percent, total seedling length, seed vigour index, root length, shoot length, relative elongation ratio of root, relative elongation ratio of shoot, phytotoxicity percent were calculated. In all the calculated parameters it was found that the aqueous extracts of both sorghum and sunflower are highly allelopathic to Phalaris minor and they have a very little effect on wheat. Both sorghum and sunflower aqueous extracts significantly reduced the germination of Phalaris minor as compared to control (distilled water), but sunflower was more allelopathic than sorghum with 85.5% of germination inhibition.