Allelopathic interaction of an alien invasive specie Anthemis cotula on its neighbours Conyza canadensis and Galinsoga parviflora

We studied the allelopathic effects of aqueous leaf leachate of alien invasive plant Anthemis cotula L., on seed germination and seedling growth of its two co-associates: Conyza canadensis (L.) Cronq. and Galinsoga parviflora Cav. in filter paper and soil bioassays. Allelopathic inhibition of seed germination showed species-specific and dose-dependent response with highest inhibition occurring at the leachate concentration of 10,000 ppm. Inhibitory effect was more pronounced in filter paper bioassay than in soil bioassay and G. parviflora was more sensitive to allelochemical(s) than C. canadensis. Interestingly, the seed germination of A. cotula was promoted by its own leachate at low concentration and inhibited at high concentration. Contributory role of allelopathy and soil in relation to invasiveness of A. cotula is highlighted.