Predicting the Evolution and Dynamics of Herbicide Resistance in Weed Populations

Abstract

Herbicide resistance jeopardizes the usefulness of valuable chemical tools and, therefore, weed management in many crop systems. Models must be developed to evaluate management tactics that prevent, delay, or reduce resistance. The complexity of biological processes involved in herbicide resistance also requires models to focus research and to integrate experiments. A population model was developed that improves upon previous attempts to predict herbicide resistance dynamics. The model incorporates plant population demographics with the Hardy-Weinberg concept for gene segregation. The model simulates the evolution, spread, and subsequent dynamics of resistance in the presence and absence of a herbicide. Analysis of model simulations identified two sets of biological processes as key factors in the evolution and dynamics of herbicide-resistant weed populations. These are processes that influence ecological fitness and gene flow. Several options are suggested as examples for the management of resistant weed populations.

Evolution, growth and phenology of Phalaris minor biotypes resistant to ACCase-inhibiting herbicides in Mexico

“…he application of systemic herbicides to control weeds exerts intense selection pressure on weed populations (up to 99.99 %) (Maxwell et al 1990), and the extensive application of herbicides with the same mode of action selects for mutations at the site of action or changes plant metabolism that allows plants to resist these herbicides (Powles & Yu 2010). The intense selection pressure reduces the effective plant population size to only few resistant individuals.…”

“…The intense selection pressure reduces the effective plant population size to only few resistant individuals. The continued use of the same herbicide on each generation increases the number of resistant individuals that can outcompete susceptible individuals (Maxwell et al 1990).…”

Relative fitness of s-triazine susceptible and resistant biotypes of Chenopodium album

“…Fitness plays an important rôle in herbicide résistance models (Maxwell et al 1990). In the présence of s-triazines, the résistant biotype is more fit than the susceptible because of its capacity to survive and reproduce.…”

Effect of herbicide treatments on the weed mass in a long-term experiment in Martonvásár

“…Only in long-term experiments is it possible to determine the effects of individual herbicides on the dynamics of the weed population and to monitor the transformation of the flora. In addition, long-term experiments can be used to trace the development of herbicide resistance, and in particular to check the predictions made by resistance simulation models (Gressel and Segel, 1978;Maxwell et al, 1990).…”