Genotypic differences to crown rot caused by Fusarium pseudograminearum in barley (Hordeum vulgare L.)

Crown rot (CR), caused predominantly by Fusarium pseudograminearum, is a serious cereal disease for semi-arid regions worldwide. Growing resistant cultivars has long been recognized as an essential component in effectively managing this disease, and successful breeding requires quality sources of resistance. This paper reports the first germplasm screening to identify CR resistance sources in barley. A total of 1047 genotypes, selected to represent different geographical origins and plant types, were assessed. Several genotypes with high levels of resistance were identified. As expected, those with the best resistance were predominantly landraces or wild barley accessions. Surprisingly, genotypes with the best CR resistance with known origins were mainly derived from East Asia where CR is not a major cereal disease. Further, the majority of the genotypes with the best CR resistance are slow growing, although such genotypes accounted for only a small proportion of all those assessed in this study. Possible explanations for these intriguing phenomena are discussed.