Multiple herbicide resistance in grass weeds

Abstract

Evolved resistance to herbicides in black-grass is a major constraint to cereal production in the UK. This project examined the evolution and management of herbicide resistance in black-grass, from the genetic to the agroecosystem level.

Multiple herbicide resistance (MHR), whereby black-grass evolves resistance to multiple active agents irrespective of chemistry or mode of action, has been a particular focus for the project.

Arranged into five work packages, the project has addressed five key questions:

• What is the molecular physiological basis of MHR?

• What is the extent and impact of MHR?

• What are the major drivers of resistance evolution?

• Can applied evolutionary models aid in resistance management?

• What are the economic and environmental consequences of novel weed and resistance management?

Cutting-edge research approaches were used to understand herbicide resistance and its evolution in the field. The results were used to develop new tools and knowledge for black-grass management.

The key outcomes from the programme are:

• Key proteins that are causatively linked to MHR have been identified.

• Understanding how these proteins function in resistance and how they could be disrupted in future have been improved.

• Evidence for sub-types of MHR, linked to specific herbicide chemistries, has been found.

• Latent viruses in black-grass, which could be of value in future biocontrol programmes, have been characterised.

• Epigenetic mechanisms were deemed unlikely to be an evolutionary driver of MHR inheritance.

• The first evidence for active roles for transporter proteins functioning in MHR and their coupled function with detoxifying enzymes was found.

• Practical diagnostics for MHR in black-grass, which can be used to detect resistance in the field in 10 minutes, have been developed.

• A national audit of resistant black-grass populations has been conducted an linked to previous management.

• A characterised collection of herbicide resistant black-grass populations provide an essential research resource.

• Knowledge that can help reduce the likelihood of resistance evolution has been underpinned.

• Predictive models of herbicide resistance have been aligned to on-farm decisions.

• Environmental and economic valuation of cost and mitigation of resistance has been published.