Impact of Ramularia collo-cygni on Barley Malt Quality and Potential for Resistance Breeding

This research investigates the impact of the emerging fungal pathogen Ramularia collo-cygni (Rcc), the causal agent of Ramularia Leaf Spot (RLS), on barley malt quality and evaluates the potential for disease control through host-resistance. Rcc is a growing global threat to barley crops and downstream industries such as brewing and distilling. As fungicide resistance increases, the development of low-input control methods becomes essential.

The study explores the resistance potential of genetically diverse barley landraces compared to elite varieties. Field trials will assess phenotypic disease symptoms under natural and fungicide-treated conditions. Genotypic data from these landraces will be used to identify potential candidate resistance loci and genes.

In parallel, the project investigates how Rcc affects malting quality. Pre-malt and malt quality traits, including germination energy, enzyme activity, starch composition, B-glucan content, and wort quality parameters such as free amino nitrogen and density, will be analysed. Rcc DNA will be tracked throughout the malting process, with a specific focus on whether steeping, germination, and kilning affect infection levels. The study also tests hot water pre-treatment as a potential method to reduce seed-borne Rcc infection.

By integrating pathology, genomics, and malting science, this project aims to enhance understanding of Rcc, inform breeding strategies for disease resistance, and safeguard the quality of barley malt critical to the UK's food and drink sector.