Effect of Clodinafop Propargyl and Tribenuron-Methyl Herbicides with Codacide Adjuvant on Wheat Yield and Yield Components (Triticum aestivum)

In order to investigate the effect of codacide adjuvant on the efficacy of clodinafop propargyl and tribenuron methyl, a field experiment was carried out on wheat at the Iranian Research Institute of Plant Protection in Alborz province during 2013-2014 growing season. Treatments included tribenuron methyl at three doses (10.5, 12.75 and 15 g a.i. ha-1), tribenuron methyl at three doses (10.5, 12.75 and 15 g a.i. ha-1) 0.25% V/V codacide, clodinafop propargyl at three doses (0.048, 0.064 and 0.08 L a.i. ha-1), clodinafop propargyl at three doses (0.048, 0.064 and 0.08 L a.i. ha-1) 0.25% V/V codacide, and weed-free control. Herbicides were sprayed at tillering stage of wheat. Results showed that clodinafop propargyl at 0.08 L a.i. ha-1 performed better regarding grass weed control and application of codacide adjuvant with this herbicide increased its efficacy. Application of tribenuron methyl (12.75 g a.i. ha-1) codacide resulted in highest reductions in broad-leaved weed density and dry matter (95% and 93%, respectively), which was not significantly different with weed-free control. Wheat biological yield (3275 kg ha-1), grain yield (2200 kg ha-1) and the number of fertile spikelets/spike (6.26) were 22, 40 and 13% higher than the weed-infested control, respectively. The lowest yield among herbicide treatments belonged to tribenuron methyl (10.5 g a.i. ha-1) with harvest index of 34.04% and 36.50 fertile spikelets/spike.