Effect of Isoproturon With and Without Adjuvants on Photosynthetic Attributes of Wheat and Its Associated Weeds

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.

Efficacy of Metribuzin Doses on Physiological, Growth, and Yield Characteristics of Wheat and Its Associated Weeds

“…These fallouts are in promise with the findings by Bibi et al (2008) who exposed that herbicides have substantial impacts on wheat of 1,000-grain weight. Similarly, Javaid et al (2020) also stated that when isoproturon was applied as a foliar spray, the highest biological yield was obtained. Hamouda et al (2021) concluded that the addition of Argal or Techno oil to herbicides spray solutions at reduced rates, especially at three-fourths of the recommended rate resulted in enhancing the herbicidal activity against weeds and increasing wheat grain yield.…”

“…Phalaris minor , M. indica , F. indica , and A. arvensis are weeds of winter wheat and cause a severe reduction in wheat yield if not controlled at the appropriate stage ( Abbas et al, 2018b ; Javaid et al, 2020 ). However, an effective dose, optimum time, and suitable mixture of herbicide along with adjuvants is required to suppress the weed growth and enhance wheat yield ( Javaid and Tanveer, 2013 ; Safdar et al, 2021 ).…”

“…Similarly, Khalil et al (2010) also revealed that greater numbers of spike-bearing tillers were obtained with the application of carfentrazone-ethyl + isoproturon as compared with weedy check treatment. The increment in spike length, the height of the plant, and grains per spike with all treatments of metribuzin over the weedy check might have been due to lower weed-crop competition for available resources that enhanced the water and nutrient use efficiency of wheat crop ( Javaid et al, 2016 , 2020 ; Shah et al, 2018 ). Our findings suggested that the addition of Bio-power enhances the efficacy of metribuzin even at lower doses (105 or 140 g a.i ha –1 ) in terms of spike length, the height of the plant, and grains per spike in comparison with Ad-500 or without adjuvant treatments.…”

“…Our findings suggested that the addition of Bio-power enhances the efficacy of metribuzin even at lower doses (105 or 140 g a.i ha –1 ) in terms of spike length, the height of the plant, and grains per spike in comparison with Ad-500 or without adjuvant treatments. The greater grains per spike resulted in metribuzin + adjuvant-treated plots were due to the least competition of weeds and maximum photosynthates produced by the wheat plant ( Javaid et al, 2020 ). According to Ashrafi et al (2009) , the application of isoproturon, triasulfuron, and bromoxynil + MCPA expressively enhanced the yield constituents of wheat over weedy check.…”

“…Metribuzin, an effective postemergence triazine group herbicide with the mode of action of photosynthesis inhibition ( Shah et al, 2009 ; Štěpánová et al, 2012 ), is often applied to restrict the broadleaf and annual grass weeds in wheat, potatoes, and tomatoes ( Majumdar and Singh, 2007 ). The efficiency of herbicides that are used after emergence can be enhanced by adding adjuvants ( Javaid et al, 2012 , 2020 ; Moraes et al, 2021 ). Adjuvants help to reduce herbicide dose and improve its biological activity by altering the surface tension of spray solution, increasing absorption, translocation rate, effect on atomization, and enhanced penetration ( Hamouda et al, 2021 ).…”