Role of secondary metabolites of wild marigold in suppression of Johnson grass and Sun spurge

ABSTRACT

OBJECTIVE: To analyze the wild marigold [(Tagetes minuta L.) (T. minuta)] leaf extract with respect to phytochemicals and allelopathic activity. METHODS: The aqueous extracts of T. minuta leaves at concentrations of 50%, 75% and 100% were prepared. Preliminary phytochemical analysis was carried out and then allelopathic effect of T. minuta on root length, shoot length, germination, fresh and dry weight of Johnson grass and Sun spurge was tested on filter paper and in soil. RESULTS: Qualitative phytochemical analysis showed the presence of alkaloids, tannins, saponins, flavonoides and terpenoids. The higher concentrations proved to be significantly effective in reducing almost all the parameters of Sun spurge and Johnson grass in filter paper bioassay. Supplemented with the soil, all concentrations of leaf extract showed reduction in germination, root and shoot growth, fresh and dry weight of Sun spurge; however, 100% concentration significantly reduced the germination of Johnson grass. CONCLUSIONS: This study suggests that marigold allelochemicals can be used as an integrated weed management for the production of better crop yield.