The Effects of Different Application Times of Broadleaf Herbicides on Winter Wheat Sayed Komeil Sayed Shourbalal*1 And Lida Hashemi2 1-PhD Student of agronomy, Department of Agronomy and Plant Breeding, Khorasgan (Isfahan) Branch, Islamic Azad University, Isfahan, Iran 2-PhD Student of genetic and Breeding, Department of Agronomy and Plant Breeding, Khorasgan (Isfahan) Branch, Islamic Azad University, Isfahan, Iran * Corresponding author email: komeil_shourbalal@hotmail.com Received: Accepted: ABSTRACT To Investigate the effects of different application times of broadleaf herbicides on winterwheat, a study was carried out (2015-16) in research farm of Islamic Azad University- Arak Branch as split plot experiment in randomized complete blocks design with twelve treatments and three replications. Main treatments were 2, 4-Dichlorophenoxyacetic acid (2,4-D), no herbicide, tribenuron-methyl, 2, 4-Dichlorophenoxyacetic acid (2,4-D) + tribenuron-methyl and subplots were time of using herbicides at initial establishment, tillering and start of stem elongation. Studied traits were the number of grains per spike (NGS), number of leaves per plant (NLP), spike’s dry weight (SDW), total dry weight (TDW) and grain yield (GY). According to the results, the highest GY (5.52 tha−1) was obtained from 2,4-D at start of stem elongation whereas the treatment of no herbicide at initial establishment had the lowest yield (4.12 tha−1). Also, the highest NGS (52.67) was produced by using of 2,4-D application at start of stem elongation which was not different from application 2,4-D at two other times. The lowest NGS (41) was belonging to no herbicide treatment. Keywords: 2,4-D, Tribenuron methyl, Tillering, Grain yield, Winter wheat تفاصيل المقالة