The effect of growth indices in competitive ability of some canola (Brasica napus) cultivars against wild mustard (Sinapis arvensis).

In order to evaluate the interference of wild mustard on growth indices of Canola cultivars an experiment was carried out in Agricultural and Natural Resources Research Institute of Gorgan during 2005-2006 growing season. The experiment was established as a randomized completely block design in a factorial arrangement of treatments with three replications. Canola cultivars, Zarfam, Sarigol, Talayh, R.G.S 003, Option 500, Hayola 401 and Hayola 330 were kept under weed free and weed infested conditions. The results indicated that, wild mustard resulted in reduction of canola dry matter, leaf area index, leaf area index duration and crop growth rate, significantly. The maximum dry matter, leaf area index and crop growth rate in control plots (weed free treatment) belonged to Hayola330 cultivar. The maximum and minimum reduction rate of dry matter and leaf area index of canola cultivars was obtained in control Option500 and Zarfam cultivars respectively. Results revealed, cultivars with higher leaf area index, relative leaf area expansion rate and better vertical leaf area distribution could be more competitive in weed-infested conditions, and can be used in breeding programs to enhance competitive ability of canola cultivars

Dose response of some wheat field grass weeds under field and greenhouse conditions to three formulations of

In order to investigate the dose response of some grass weeds of wheat fields to different Fenoxaprop-p ethyl formulations, field experiments were conducted in Khouzestan, Golestan and greenhouse experiments were conducted in Tehran, during 2003-2004. Experimental factors were three formulations of Fenoxaprop-p ethyl (Golsam, Giya and Bieser feld), each applied at four doses (0.4, 0.8, 1.2 and 1.8 L/ha). Dose response curves of the percent of reduction in number of weeds and their dry weight compared to the untreated control were fitted. Weed floras included winter wild oat (Avena ludoviciana Dur.), canary grass (Phalaris minor Retz.) and ryegrass (Lolium perenne L.) in Khouzestan, and the same weed flora but less canary grass in Golestan and winter wild oat in the greenhouse study. Results indicated that there was no significant difference between Giya and Bieser feld formulations. The efficacy of these formulations was better than Golsam. Also, the reduction in dry weight of narrow leaf weeds was similar in field studies but not in greenhouse study. Dose response of narrow leaf weeds to all Fenoxaprop-p ethyl formulations was not satisfactory at the recommended dose (1 L/ha) indicating that this herbicide should be applied at higher doses or be replaced with another narrow leaf herbicide like Clodinafop-propargil

Chemical control of weeds in wheat (Triticum aestivum L.) in Iran

Experiments were conducted in 2006-2007 at six research stations of the Iranian Plant Protection Research Institute to study the efficacy of different herbicides to control weeds in wheat. Treatments included mesosulfuron-methyl plus iodosulfuron-methyl-sodium plus mefenpyr-diethyl (WG) at 45 + 45 + 135 g. a.i./ha, respectively, sulfosulfuron at 21, 31.5, 42 and 51 g. a.i./ha, chlorsulfuron at 15 g. a.i./ha, bromoxynil plus MCPA at 600 g. a.i./ha with clodinafop propargyl at 64 g. a.i./ha, sulfosulfuron plus metsulfuron-methyl at 36 g. a.i./ha, mesosulfuron-methyl plus iodosulfuron-methyl-sodium plus mefenpyr-diethyl (OD) at 15 + 3 + 45 g. a.i./ha, respectively, and a full season weed-free control. Herbicides were applied at wheat tillering. Results showed that sulfosulfuron plus metsulfuron-methyl, and bromoxynil plus MCPA with clodinafop propargyl resulted in satisfactory weed control and wheat grain yield at most locations. Weed control efficacy of both formulations of mesosulfuron-methyl plus iodosulfuron-methyl-sodium was variable across locations. Efficacy of the OD formulation appears to depend upon location, so that application of this herbicide at Shiraz and Gorgan resulted in better weed control compared to use of the WG. Satisfactory performance of the OD formulation at Gorgan and Shiraz could be attributed in part to the even pattern of rainfall distribution during the growing season and wheat cultivar used, respectively. With respect to grain yield, however, the OD formulation was better than WG formulation at most of the locations