Allelochemicals from Chromolaena odorata (L.) King and Robinson for increasing crop productivity.

Wild varieties of many crop plants possess allelopathic chemicals that make them resistant to pests and weeds. During the course of selection for high yielding varieties, such genes are either rendered, weak or eliminated, resulting in loss of allelopathic attributes in crop plants. However, this quality still exists in most of the weeds, where such selection does not occur. Chromolaena odorata is reported to be highly allelopathic compared with some of the other weeds that are among the world's worst Allelochemicals are natural products and do not accumulate in soil as persistent pollutants. In its crude form at a particular concentration, C. odorata allelochemicals increased the vegetative growth, metabolite content and yield in pulses, grain crops and vegetables. In this study, the crude allelochemicals were used as seed invigorants, liquid fertilizers and as foliar spray on finger millet, cluster bean soybean, spinach and radish. The treated plants were even resistant to pests and diseases. Details of the preparation of allelochemicals, appropriate concentration, the crop growth pattern, yield assessment and biochemical analyses are discussed.