Malting Barley Production In A Challenging Policy Environment

Published on 17 March 2009 in Sustainability and Communities


The malting barley industry requires varieties which provide both a stable yield and a quality product for distilling and brewing. This is a challenge in a business environment full of uncertainty and risk. The purpose of this project is to improve disease management of barley through the development of more durable variety resistance which will lead to a reduction in fungicide use. It will also assist the industry achieve the stability and quality it requires to succeed. Maintaining effective varietal disease resistance over several cropping years has its challenges since the fungal pathogens which cause disease continually change and break down the varietal resistance. Unpredictable weather events which are one consequence of climate change also make disease forecasting a greater challenge. Changes in the types of pathogens or the populations of existing pathogens also increase uncertainty in providing malting barley requirements of the industry. Changes to pesticide legislation will also lead to an increase in uncertainty and the challenge will be to make fungicides the last line of defence as opposed to the way they are used today as the first line of defence to manage disease.

Key Points

The two key methods to manage plant disease are the use of resistant varieties and fungicides.  Over-reliance on either of these methods can lead to changes in pathogen populations resulting in the breakdown of host resistance and development of resistance of pathogens to fungicides.

This research will lead to improvements in the durability of disease management by several routes.

  • Better targeting of fungicides through improved understanding of barley diseases
  • Diversifying the range of mechanisms exploited in host defence including disease avoidance, induced resistance, disease tolerance and crop diversification
  • Identification of novel resistance genes which can be used by breeders in future barley breeding programmes
  • Improved disease forecasting and risk assessment

The approaches taken in the research need to be both economically viable and environmentally sustainable.

Research Undertaken

Barley seed is now recognised as a major source of inoculum for both rhynchosporium and ramularia. For ramularia, seed infection is a key source and airborne spores only appear once symptoms have developed. For rhynchosporium, seed infection is one of many sources of infection and weather conditions, for example, rainfall can exert a considerable influence on disease epidemics.


Crop disease (Ramularia) kills plants leading to loss of yield and quality required by the malting barley industry

Future methods of disease management will focus on seed health through non-chemical methods of control and greater knowledge on the pathogens present on seed and the movement of seed from one country to another.

Yeast and bacteria from leaf surfaces have been identified and shown to compete with rhynchosporium. Fungicides can affect this balance between leaf surface microbes, and could compromise our ability to control rhynchosporium and other pathogens.
Crop characteristics such as the height of a variety and the inclination of its leaves can influence the severity of rhynchosporium infection and its effect on yield.
Elicitors will be used to enhance the resistance of a variety to a range of pathogens, including rhynchosporium and ramularia. As a result, elicitors offer the prospect of using less fungicide in a season, while maintaining yield.
Another approach to minimise disease is to use mixtures of varieties that differ in resistance and this may have significant effects on the evolution of pathogen populations and their ability to overcome the crop’s resistance mechanisms.
Making best use of historical information is an important basis of understanding how disease epidemics may change in the future. The crop disease information collected since 1983 will be used to study the impact of climate change on crop disease.
Crops in a flooded field
Crops in the future will have to survive extreme weather events including flooding and drought

Policy Implications

The malting barley industry’s requirement to use a single variety over a long period of time is currently only achievable through the reliance on fungicides to manage disease, particularly in the later years of a variety's lifespan. This research demonstrates alternative methods to fungicides, but the unpredictability of disease outbreaks through changes in the pathogen and environment as a consequence of extreme weather events mean fungicides will continue to be required as a method of last resort to manage disease.

Getting the malting barley industry to accept different methods in the short term will be a challenge since there is a perception that mixing varieties causes processing difficulties.
Longer term aims in designing varieties which can tolerate or escape from disease threats is more achievable. The cost benefit analysis and research in this programme will provide useful information to determine which alternative methods need to be pursued over the long term which:
·         meet the requirements of the industry
·         are cost-effective
·         reduce our reliance on fungicides
Over the next ten years, many pesticides used today will no longer be available to the industry as a consequence of a review of EU Directive 91/414EEC. This could have immediate implications arising from the loss of existing active ingredients. There are also longer term implications for pesticide resistance to the limited range of active ingredients remaining on the market.


Dr Simon Oxley, Senior Researcher (Plant Pathology), SAC


Sustainability and Communities

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