Development and validation of markers closely linked to crown rot resistance in wheat and barley

Crown rot (CR), caused by various Fusarium species, is a chronic cereal disease in Australia and many other parts of the world. As part of our objective of improving the efficiency of breeding CR-resistant wheat and barley varieties, we have been searching for novel sources of resistance and identifying new genes conferring CR resistance in the two crops. This paper reports on the development of more closely linked markers and validation of the effects of the previously identified wheat 3B CR quantitative trait loci (QTL) and the barley 3H major CR locus using four wheat and three barley validation populations. With an effect varied from 36.7 to 59.4% in wheat and 29.4 to 55.2% in barley, the validation experiments demonstrated that both of the 3B and 3H CR locus have a stable and significant effect in reducing CR severity at different genetic backgrounds. The huge effect of a single QTL as the CR loci detected in this study warrant a significant value of incorporating these two genes in wheat and barley breeding. The possible homoeologous relationship between these two major CR loci is preliminarily investigated by comparative mapping the two genomic regions and it warrants further investigation. Keywords Wheat; Barley; Crown rot; Validation; Com