Speaker
Description
Weeds are a major threat to crop production, causing the highest potential yield losses.Already since the late 1960s conventional agriculture has primarily relied on the application of herbicides for controlling weeds.However, the number of available herbicides is limited and they often share the same mode of action. The overuse of those active ingredients has led to the widespread evolution of herbicide resistance in weeds.Weedy traits that increase the persistence, like seed banks and asexual propagation, impose further challenges to weed management.Effective and sustainable weed management strategies are urgently needed. Mathematical modelling can contribute to our understanding of the processes that drive the evolution of resistance in weeds and inform the development of management tactics. In this talk, I present a population-based model of seed and rhizome propagated perennial weeds, specifically Sorghum halepense, incorporating the complete complex life cycle and control measures of herbicide application and tillage.I show that the natural frequency of target-site resistance mainly depends on the resistance cost and less on its dominance.I highlight the pivotal role of the sexual phase of the life cycle, including self-pollination and seed bank dynamics, in the persistence and rapid herbicide resistance adaptation of Sorghum halepense.In particular, I illustrate how the seed bank helps preserve genetic diversity under recurrent selective pressure imposed by herbicides. Moreover, I indicate the potential of the seed bank to ensure population survival under control by delaying extinction and increasing the probability that resistant mutants establish. I show that the speed of resistance evolution in self-pollinated plants increases in such seed and rhizome-propagated weeds.
