Spot blotch or leaf spot, most common form of leaf blights of barley, caused by Bipolaris sorokiniana (earlier Helminthosporium sativum), is a serious foliar disease of barley (Hordeum vulgare L.) which may cause a significant yield loss of more than 30% at adult plant stage. The Quantitative Trait Loci (QTLs) studies in barley have concluded debatable complex inheritance of leaf blight resistance due to different genetic backgrounds of mapping populations with very few reports coming from all over the world. An integrated approach is recommended with host resistance as a major component to identify QTLs and specific markers targeted for genomic regions involved in spot blotch resistance in barley lines. Spot blotch resistant (DWR49) and susceptible (RD2503) lines were crossed to identify QTLs associated with resistance. 283 SSR and STS primers specific to all the seven chromosomes were used to screen the parental lines, of which 50 showed polymorphism over resistant and susceptible bulks and used for genotyping of 142 RILs (Recombinant Inbreed Lines) of the cross DWR49 X RD2503 (D/R). Two QTLs, Rcs-qtl-1H-1 and Rcs-qtl-1H-2 on chromosome 1H explaining phenotypic variance of 62.2% and 7.4% were found to be associated with spot blotch resistance.
