Evaluation of Ready-Mix herbicide Efficiency of Clodinafop Propargil+ Metribuzin in Comparison with Registered Herbicides in Weed Control of Wheat (Triticum aestivum) in Fars

Introduction Wheat (Triticum aestivum) is one of the most important crops in Fars province and Iran. The area under cultivation of this crop is 337,000 hectares in Fars’s province. The weeds are one of the most famous factors limiting in the production of wheat in Iran and the world. Weeds can decrease grain yield of wheat by competing for resources such as water, light and nutrients and production of allelopathic compounds. If weeds are not controlled at this crop, cause great damage to the wheat. The amount of weed damage in wheat fields of Iran has been reported to be about 20 to 25%. The most important weeds of wheat in Fars are including Mavla neglecta Wallr., Centaurea solstitialis L., Veronica persica L., Carthamus oxyacanthus M.B., Capsella bursa-pastoris, L., Descurainia Sophia (L.) Webb&Berth, Hirschfeldia incana L., Lolium rigidum L., Avena fatua L., Bromus tectorum L. Application of herbicides is the most prevalent method of weed control in wheat fields. There are 26 herbicides registered for weed control in wheat in Iran, which are mainly used post-emergence. Herbicides are recommended for weed control in wheat included of Total, Othello, Atlantis, Geranestar, Bromicid MA, Apiros, Tapik and Axial. Therefore, it is necessary to register new herbicides with different site of action in this crop. This experiment was conducted to investigate the new herbicide efficacy of clodinafop propargil+ metribuzin in control of wheat fields, determination of the most appropriate dose, comparison of the effectiveness of new herbicide with the herbicides was recorded in wheat and the reaction of wheat to the herbicideMaterials and Methods In order to study the effect of herbicides to control weeds of wheat fields, an experiment was conducted during 2020- 2021 at Fars Agricultural and Natural Resources Research and Education Center, Darab, Iran. Plots were located on a clay loam soil with pH 7.9. This experiment was carried out in randomized complete block design with 13 treatments and 4 replications. The treatments included post emergence application of Total (methsulfuron+ sulfosulfuron, 80% WG) at dose rate of 40 g ha-1, Othello (mesosulfuron+iodosulfuron+ diflufenican, 6% OD) at dose rate of 1.6 L ha-1, Tapik (clodinafop propargil, 8% EC) + Geranestar (tribenuron, 75% DF) at dose rates of 0.8 L ha-1+ 20 g ha-1, Tapik (clodinafop propargil) + Bromicid MA (bromoxynil+ MCPA, 40% EC) at dose rates of 1 L ha-1+ 1.5 L ha-1, ACM– 9 (clodinafop propargil + metribuzin, 29% WP) at dose rates of 500, 600, 700 g ha-1, Shagun 21-11 (clodinafop propargil+ metribuzin, 54% WG) at dose rates of 200, 300, 400, 500, 600 g ha-1 and weeding control. The herbicides were applied using a Matabi sprayer equipped with an 8002 flat fan nozzle tip delivering 350 L ha-1 at 2 bar spray pressure. Weed numbers and dry weights were determined in random 0.50-m2 quadrates per plot. The grain yield and biological yield were recorded for a 2 m2 and 0.50 m2 from each plot, respectively. Parameters were recorded including and control percentage of density, weed biomass, plant height, grains per spike, number spikes, 1000 grains weigh, grain yield and biological yield. Statistical analyses of data were done with SAS var 9 software and comparison of mean was tested using the LSD test at 5% level.Results and DiscussionThe weed infestations in the study consisted of Hirschfeldia incana L., Centaurea pallescens L., Veronica persica L., Malva neglecta L., Lolium rigidum L., and Convolvulus arvensis L. Among these weeds, Centaurea pallescens had the highest relative weight at 24%, while Convolvulus arvensis had the lowest relative weight at 8%. In terms of relative density, Veronica persica had the highest value at 44%, while Convolvulus arvensis had the lowest at 7%. Statistical analysis of the data revealed that the application of herbicides significantly reduced weed density and biomass. It also led to increased plant height, number of spikes per m2, grains per spike, 1000 grains weight, grain yield, and biological yield. Visual observations confirmed the effective control of these weeds using the ACM herbicide at a dose rate of 700 g ha-1. The best herbicide treatment for weed control was Tapik+ Bromicid MA, followed by ACM herbicide at a dose rate of 700 g ha-1. The ACM herbicide at a dose rate of 700 g ha-1 resulted in a significant reduction in biomass for Malva neglecta (87%), Lolium rigidum (76%), Hirschfeldia incana (81%), Centaurea pallescens (90%), Veronica persica (86%), and total weed (80%) compared to the weed control. Furthermore, when the ACM herbicide was applied at a dose rate of 700 g ha-1, the grain yield and biological yield were 5.65 and 14.51 tons ha-1, respectively. This treatment also led to a 26% increase in grain yield and a 25% increase in biological yield compared to the control.Conclusion Results showed that applications of powder formulation of clodinafop+ metribuzin herbicide at dose rate of 700 g ha-1 had acceptable weed control efficacy and increased wheat yield. Therefore, the application of clodinafop+ metribuzin (WP) herbicide at dose rate of 700 g ha-1 is suggested for wheat fields.