Publication

Abstract : Globally, the intensive herbicide usage has resulted in the evolution of many herbicide-resistant weeds. Rigorous herbicide usage and lack of diversity in herbicide management would rapidly accumulate resistance mutations in the weed populations. Therefore, applying herbicides at a reduced rate that provides satisfactory weed control was believed to be a strategy to reduce the frequency of herbicide resistance mutations in weed populations with the additional benefits of low input cost and less herbicide load to environment. All these considerations would have contributed to the absence of regulations in many countries to mandate the strict adherence of recommended herbicide rates. Paradoxically, lack of diversity in herbicide usage coupled with faulty herbicide management practices has resulted in the emergence of herbicide-resistant weeds in different agro-ecosystems. Evolution of herbicide resistance was very rapid in Australia, where the recommended rates of herbicides was the lowest in the world and farmers use lower than recommended rates of herbicides for economic reasons. In the light of the alarmingly increasing herbicide resistance cases, in the mid-1990s, scientists hypothesized the possibility of the accumulation of minor resistance mutations, in addition to major herbicide resistance mutations as a possible reason for the rapid evolution of herbicide resistance, although there were no studies to support this theory at that time. However, recent studies have confirmed that the recurrent application of a herbicide and herbicide selection at low dosages can be a major reason for the rapid evolution of herbicide resistance. This paper reviews the potential of major weed species to evolve rapidly under low herbicide through the accumulation of polygenic resistance traits. In addition, the feasibility of a population genetics approach in herbicide resistance management in tune with the high dose refuge strategy for insecticide resistance management is proposed for the first time and discussed.