Allelopathic effect of Niger Plant (Guizotia abyssinica L.) on abundance of selected weeds

Abstract

Plants release many secondary metabolites to the environment that can be harnessed for important uses. These secondary metabolites are known as allelochemicals. The current worldwide demand for cheaper, more environmentally-friendly weed management technologies have motivated a number of studies on the allelopathic interaction between crops and weeds. Niger plant has been observed to have allelopathic effects on certain weeds. In order to evaluate the influence of Niger plant on selected weeds, an experiment was laid out in Randomized Complete Block Design (RCBD) with three replicates. Three cultivars of beans (Rosecoco, Mwitemania and Mwezi Mbili) were used. Data collection included the total number of four prominent weeds over a span of four weeks. A 50 x 50 quadrat was laid on the same spot in all the treatments and the weeds enclosed within were counted separately. Data analysis was done by ANOVA in Genstat and results were presented using graphs. Results showed that Niger plant enhanced the bean growth and development, whereas it inhibited the germination and growth of some weeds i.e. field mustard, broom weed, double thorn and couch grass. It was concluded that Niger plant exhibited negative allelopathy on the weeds that were studied and positive allelopathy on all the bean cultivars. From the results, it is recommended that further research needs to be carried out on more crops and more weeds to have an in-depth understanding of this subject.