Crown rot of winter cereals: integrating molecular studies and germplasm improvement

Abstract

Crown rot of winter cereals is a major constraint on grain production across most growing regions in Australia, particularly where stubble retention is practiced to maintain soil structure and retain soil water. The predominant cause of this disease is infection with Fusarium pseudograminearum (Fpg), although in some southern areas Fusarium culmorum infections are also significant. These Fusarium species are able to grow saprophytically on stubble remnants over the summer and provide inoculum for crop infection in the following season. Losses due to crown rot are highest in seasons featuring a dry finish in which maturing plants experience water stress, with symptoms including basal stem browning and white heads bearing no grain. Control of this disease is challenging and is currently based on management practices centred on crop rotation strategies. At present, there are no resistant commercial varieties of bread wheat, durum or barley available for deployment. Durum wheats are particularly susceptible. Here we report on recent successes in pyramiding sources of partial resistance and discuss progress in transferring resistance from hexaploid sources into a durum background.