Response of Wild Barley (Hordeum spontaneum) and Wheat (Triticum aestivum) to Different Herbicides in Greenhouse

In order to study the response of wheat (Triticum aestivum) cv. Chamran and wild barley (Hordeum spontaneum) to different herbicides، a pot dose response experiment was conducted in a completely randomized design with three replication at Research Greenhouse of Ferdowsi University of Mashhad in 2008. Different doses of herbicides including Clodinafop propargyl، Pinoxaden، Sulfosulfuron، and Metsulfuron-methyl+ Sulfosulfuron، were applied post-emergence at 2-3 leaf stage of wheat and wild barley and Isoproturon+Diflufenican was applied pre-emergence. Plant dry weight of each treatment was determined three weeks after herbicide application، then GR50، GR25، and herbicide selectivity indices were determined for each herbicide. Results showed that due to wild barley high tolerance، no herbicide could completely control this weed in wheat without injury to wheat. Among all herbicides، Metsulfuron-methyle+Sulfosulfuron was the best one for selective control of wild barley in wheat، which reduced wild barley biomass by 32% in recommended dose. Clodinafop propargyl and Pinoxaden، even at higher doses couldn’t reduce wild barley biomass and can not be used for wild barley control in wheat. Sulfosulfuron had little influence on wild barley at recommended dose، but at higher doses reduced both wild barley and wheat biomass significantly.