Present address: Warwick HRI, University of Warwick, Wellesbourne Warwickshire CV35 9EF, UK
Evidence for an ecological cost of enhanced herbicide metabolism in Lolium rigidum
Article first published online: 5 MAY 2009
© 2009 The Authors. Journal compilation © 2009 British Ecological Society
Journal of Ecology
Volume 97, Issue 4, pages 772–780, July 2009
How to Cite
Vila-Aiub, M. M., Neve, P. and Powles, S. B. (2009), Evidence for an ecological cost of enhanced herbicide metabolism in Lolium rigidum. Journal of Ecology, 97: 772–780. doi: 10.1111/j.1365-2745.2009.01511.x
- Issue published online: 16 JUN 2009
- Article first published online: 5 MAY 2009
- Received: 16 November 2008; accepted: 2 April 2009Handling Editor: James Cahill
- enhanced herbicide metabolism;
- fitness costs;
- herbicide resistance;
- plant defence;
- resource allocation;
- resource competition;
- 1In some cases, evaluation of resource competitive interactions between herbicide resistant vs. susceptible weed ecotypes provides evidence for the expression of fitness costs associated with evolved herbicide-resistant gene traits. Such fitness costs impact in the ecology and evolutionary trajectory of resistant populations.
- 2Neighbourhood experiments were performed to quantify competitive effects and responses between herbicide-susceptible (S) and resistant (R) Lolium rigidum individuals in which resistance is due to enhanced herbicide metabolism mediated by cytochrome P450.
- 3In two-way competitive interactions between the S and R phenotypes, individuals of the S phenotype were the stronger effect competitors on both a per capita and per unit-size basis. The S phenotype also exhibited a stronger competitive response to wheat plants than did the R phenotype, displaying significantly greater (30%) above-ground biomass at the vegetative stage. When subjected to competition from wheat, R individuals produced significantly fewer reproductive tillers and allocated fewer resources to reproductive traits than individuals of the S phenotype.
- 4The role of potential mechanisms underlying this resistance cost driven by traits such as plant size and tolerance to low resource availability, as well as the evolutionary implications of the results are discussed.
- 5Synthesis. Evolved herbicide resistance due to enhanced-herbicide metabolism mediated by cytochrome-P450 in L. rigidum has been shown to be accompanied with an impaired ability to compete for resources. These results are consistent with the resource-based theory that predicts a negative trade-off between growth and plant defence.