Herbicides: History, Classification and Genetic Manipulation of Plants for Herbicide Resistance (original) (raw)
2014, Sustainable Agriculture Reviews
Weeds have known to affect human activities including agriculture since ages. Looking at the global scenario the major contributors of crop loss are weeds, followed by animals and pathogens. World War II started the 'chemical era' for the development of herbicide. Herbicides are used to kill weeds and are still the largest product type accounting for 47.6 % of global pesticide sales followed by insecticide (29.4 %), fungicide (17.5 %) and others (5.5 %). Herbicides have been classifi ed in various ways but classifi cation based on site of action of herbicide is comparatively better as herbicide resistance management can be handled more properly and effectively. Commonly used herbicides globally are generally broad spectrum and nonselective which restricts their use in arable lands. Thus there is need to modify the crops genetically so that the crop plants remain unaffected by herbicide application. Different strategies have been used either individually or in combination to develop transgenic plants. Reports suggest that the global area covered by herbicide-resistant transgenic plant outnumbers the area covered by any other genetically modifi ed plants. However, inadvertent use of herbicides has helped in evolution of resistant weeds. This problem is now a subject of discussion worldwide. Integrated herbicide management is important to avoid selection pressure for the evolution of resistance. Transgenic plants have really helped the mankind in increasing the crop yield but use of transgenic plant is still a debatable topic which needs meticulous research, observations and experimentations for a fi nal statement either in favour or against .
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