Response of Wheat and Accompanied Weeds to Allelophathic Extracts of Rice Straw and Some Herbicides

The objective of this work is to evaluate the allelopathic effects of the aqueous and methanolic extract of rice straw (Oryza sativa L.) on wheat (Triticum aestivum L.) and wheat weeds, including wild oat (Avena fatual L.) andcanary grass (phalaris minor). Three concentrations (5, 10 and 20%) of each aqueous and methanolic extract as well as the recommended dose of chemical herbicide clodinafop propargyl (140 g/ fed) and diclofopmethyl (750 ml/fed) were used on the tested plants as a postemergence treatments. Response of the treated plants were measured by using 7 parameters includes: germination %, seedling shoots and root length, dry weight, chlorophyll content, plant height, plant number and spike length and weight of treated wheat. Data of each parameter were discussed separately. Generally, treatments with higher concentrations (20% rice straw aqueous and methanolic extract) showed negative effects on wheat weeds at the same time cause increasing the wheat productivity. However, rice straw methanolic extracts showed suppressive effect on wheat seed. Comparing the efficacy of the straw extract with the tested conventional herbicides, the obtained data showed that clodinafop propargyl and diclofopmethyl were the most effective against the time tested weeds as it severely reduced the weed population and other tested parameters.