Understanding ergot risk in spring barley

Abstract

The cereal disease commonly known as ergot is caused by the fungus Claviceps purpurea. This study comprises two field trials using spring barley varieties on the HGCA Recommended List. Ergot symptoms which developed through natural infection were assessed. Plots which were inoculated with the fungal pathogen were also assessed for disease symptoms. The results based on the 2007 season provide information on the potential genetic susceptibility of spring barley varieties to the disease. Cereals most susceptible to ergot are those with an open flowering habit which flower over a long period of time (i.e. rye). Open flowering enables the fungal spores to infect the grain sites leading to the development of ergots. Assessments of the flowering habit of the spring barley varieties were undertaken over two seasons. Differences in the flowering habit and the duration of flowering were observed. Most varieties flowered for a short duration of up to 6 days. A risk assessment was developed on the basis of the genetic resistance to ergot determined through the inoculations and on the flowering type and habit. On this basis, the assessment confirmed the susceptibility of the varieties Decanter and Maresi which both have an open flowering habit and are genetic susceptible to ergot. Varieties which showed no infection after inoculation which have a closed flowering habit were defined as being low risk. The variety Appaloosa is an example of this type of variety.