Near-isogenic lines developed for a major QTL on chromosome arm 4HL conferring Fusarium crown rot resistance in barley

Ten pairs of near-isogenic lines (NILs) were developed for a major quantitative trait locus conferring Fusarium crown rot (FCR) resistance in barley. The locus locates on the long arm of chromosome 4H and the presence of the resistance allele reduced FCR severity by between 32.8 and 63.4 % with an average of 43.9 % across these NILs. Histological and quantitative PCR analyses all confirmed that the rates of Fusarium infection and disease development were much slower in the resistant isolines compared with those in the susceptible isolines. The contrasting phenotypes in FCR severity between the isolines for each of these NIL pairs would facilitate efforts in cloning and functional analyses of genes conferring resistance to this disease.