Symptomless Infection of Barley:resistance breeding and integrated crop protection strategies (SIBLINGS)

Despite fungicide applications valued at over £25M, 'Rhynchosporium' continues to be the most problematic and economically damaging disease of barley leading to annual yield losses of ~£7M. Research has shown the importance of extensive growth of this pathogen before symptoms are visible, even on resistant cultivars, and this has changed our understanding of its epidemiology. Previously we based our understanding of resistance on visible symptoms only - this new knowledge explains some of the difficulties in managing the disease. Understanding the impact of pre-symptomatic colonisation on yield and its impact on disease management is pivotal and our breeding and crop protection strategies need to change to exploit this new knowledge. We will identify, characterise and combine sources of barley resistance to improve durability and use knowledge of the mode of action of different defence mechanisms to improve crop protection strategies to increase the effectiveness of currently available fungicides. Using host plant gene markers together with microscopy methods using fluorescently-tagged pathogen isolates we will characterise sources of resistance, identify candidate genomic locations and obtain flanking diagnostic molecular markers. This knowledge will be used to develop new varieties and to validate optimal disease management programmes against this important pathogen.