ABSTRACT:
Among various weed management strategies, chemical weed control is considered the most effective method. However, optimum dose and suitable combination of herbicide with adjuvants play a vital role in controlling weeds at an acceptable level and produce maximum crop yield. A field study was conducted to investigate the effect of post-emergence herbicide isoproturon alone or with combination of adjuvants on winter wheat and its associated weeds. The treatments were isoproturon at 175 g a.i. ha-1, 140 g a.i. ha-1 and 105 g a.i. ha-1 applied alone or with adjuvants Ad-500 or Bio-enhancer at 400 mL ha-1 each and weedy check as a control treatment. Isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1 was most effective treatment for control of Melilotus indica, Anagallis arvensis, Phalaris minor and Fumaria indica as it decreased the photosynthetic activity, fresh and dry biomass of these weeds. In case of wheat, highest productive tillers, plant height, 1000-grain weight, biological and grain yield were achieved with isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1. However, highest values of gas exchange parameters of wheat were observed where no herbicide was sprayed. It can be concluded that isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1 might be a profitable approach to achieve optimal yield of wheat by causing the maximum suppression of these tested weeds. Moreover, the herbicide at reduced dose with adjuvants was not much effective in terms of weed control or increased yield.
Keywords:
fresh and dry weight; gas exchange traits; growth and yield; herbicide doses; Triticum aestivum L.; weed control
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T1 = Weedy check, T2 = Isoproturon at 175 g a.i. ha-1, T3 = Isoproturon at 140 g a.i. ha-1, T4 = Isoproturon at 105 g a.i. ha-1, T5 = Isoproturon at 175 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T6 = Isoproturon at 140 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T7 = Isoproturon at 105 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T8 = Isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T9 = Isoproturon at 140 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T10 = Isoproturon at 105 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1.
T1 = Weedy check, T2 = Isoproturon at 175 g a.i. ha-1, T3 = Isoproturon at 140 g a.i. ha-1, T4 = Isoproturon at 105 g a.i. ha-1, T5 = Isoproturon at 175 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T6 = Isoproturon at 140 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T7 = Isoproturon at 105 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T8 = Isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T9 = Isoproturon at 140 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T10 = Isoproturon at 105 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1.
T1 = Weedy check, T2 = Isoproturon at 175 g a.i. ha-1, T3 = Isoproturon at 140 g a.i. ha-1, T4 = Isoproturon at 105 g a.i. ha-1, T5 = Isoproturon at 175 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T6 = Isoproturon at 140 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T7 = Isoproturon at 105 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T8 = Isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T9 = Isoproturon at 140 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T10 = Isoproturon at 105 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1.
T1 = Weedy check, T2 = Isoproturon at 175 g a.i. ha-1, T3 = Isoproturon at 140 g a.i. ha-1, T4 = Isoproturon at 105 g a.i. ha-1, T5 = Isoproturon at 175 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T6 = Isoproturon at 140 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T7 = Isoproturon at 105 g a.i. ha-1 + Ad-500 at 400 mL ha-1, T8 = Isoproturon at 175 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T9 = Isoproturon at 140 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1, T10 = Isoproturon at 105 g a.i. ha-1 + Bio-enhancer at 400 mL ha-1.