the impact of herbicides on weed control and physiological traits in wheat (triticum aestivum l.)

Objective: this study aimed to evaluate the impact of new and commonly used herbicides on weed control and physiological traits in wheat (triticum aestivum l.).methods: the experiment was performed as a randomized complete block design with four replications at the agricultural and natural resources research center of moghan during the 2022-2023 growing season. the wheat variety used was chamran, a winter-type cultivar. the herbicides included 2-methyl-4-chlorophenoxyacetic acid (mcpa) + furosulam (wp 42%) at rates of 300, 400, 500, 600, and 700 g/ha, fluorosulam (florex wp 10%), 2, 4-d + mcpa (u46 combi fluid 67.5% sl), bromoxynil + mcpa (bromicide 40% ec), bromoxynil + 2,4-d (buctrile univeral 56% ec), bentazone + dichlorprop (basagaran dp 56.6% sl). a hand-weeded treatment and a weedy check treatment served as controls.results: the analysis of variance of the data showed a significant difference between treatments in terms of density and biomass for weeds, and plant height, number of spikes, biomass, grain yield, chlorophyll index (spad), proline, and catalase enzyme activity for wheat. the use of 600 and 700 g/ha of mcpa + fluorosulam, u46 combifloid, bacteril universal, bromacid, and basagran dp herbicides had a favorable effect on the weed control, and resulted in a 10% to 25% increase in wheat grain yield. the results showed that the highest chlorophyll content of wheat was associated with treatments of florex, u46 combi fluid, buctrile univeral, and bromicide. but increasing the rate of mcpa + furosulam decreased the chlorophyll content in wheat. also, increasing the rate of mcpa + furosulam increased the proline content and activity of catalase enzyme in wheat.conclusion: in summary, the results indicated that treatments with a higher weed control shifted the competitive conditions towards the cultivated crop, leading to an increase in leaf weight and photosynthetic capacity, ultimately resulting in increased wheat grain yield. therefore, it seems that the use of 600 g/ha of mcpa + fluorosulam herbicide in alternation with other permitted herbicides can have an effective role in controlling weeds and increasing wheat yield.