Allelopathic research on chickpea seeds in Chhattisgarh (India) region : an overview

摘要

The term Allelopathy is derived from two Greek words Allelon means each other and Pathos means to suffer i.e., the injurious effects of one upon another. However, Molisch (1937) coined this term which refers to all biochemical interactions (stimulatory and inhibitory) among plants, including micro-organisms. It represents the plant against plant aspect of the broader field of chemical ecology. Some authors have used the term in a more restricted sences to describe only the harmful effect of one higher plant upon another. Allellochemicals which inhibited the growth of some species at certain concentrations may stimulate the growth of same or different species at lower concentrations (Narwal, 1994). Allelopathy is relatively a new branch of science(Lal and Oudhia, 1999). With the help of allelopathy, weed-crop, crop-weed, crop-crop and weed-weed interactions can easily be explained. Under field conditions weed infestation is one of the major factors responsible for yield reduction in crops. Historically, most investigators have attributed these losses to various forms of competition between the weeds and crops and allelopathic interactions between them were not considered. However, findings after 1950's have shown that allelopathic interactions between the crops and weeds were also partly responsible for such losses in crop yields. As the allelopathic effects are both positive and negative, both of these effects can be utilized for higher crop production (Oudhia et al., 1999a). Negative (stimulatory) allelopathic effects of any weed on crops can be utilized to develop ecofriendly, cheap and effective 'Green growth promoters'. Similarly, the positive (inhibitory) allelopathic effects of any weed or crops on weeds can be utilized to develop 'Green herbicides' (Oudhia et al., 1999b). Many studies conducted at the Department of Agronomy, IGAU, Raipur to know the allelopathic effects of common weeds on germination and seedling vigour of many popular agricultural crops like rice, wheat, maize, groundnut etc. and these studies have revealed that all weeds are not harmful and also beneficial extracts of these weeds can be utilized for crop production (Oudhia and Tripathi, 1999a). Chickpea is one of the major rabi crops of Chhattisgarh. Many weeds infest chickpea fields every year (Oudhia and Dixit, 1994; Oudhia and Tripathi, 1999b). Due to non-availability of any information on allelopathic effects of common chickpea weeds on germination and seedling vigour of chickpea, series of experiments were conducted during 1994-2000. The major objectives of these studies were (a) To evaluate the allelopathic potential of different parts of weeds (b) To find out farmer's friendly method for preparation of weed extracts (c) To identify the promising and potential extract for increasing chickpea production.