Mapping quantitative and qualitative disease resistance genes in a doubledhaploid population of barley (Hordeum vulgare)

Stripe rust, leaf rust, and Barley Yellow Dwarf Virus (BYDV) are important diseases of barley (Hordeum vulgare L). Using 94 doubled-haploid lines (DH) from the cross of Shyri x Galena, multiple disease phenotype datasets, and a 99-marker linkage map, we determined the number, genome location, and ef fects of genes conferring resistance to these diseases. We also mapped Resi stance Gene Analog Polymorphism (RGAP) loci, based on degenerate motifs of cloned disease resistance genes, in the same population. Leaf rust resistan ce was determined by a single gene on chromosome 1 (7H), QTLs on chromosome s 2 (2H), 3 (3H), 5 (IH), and 6 (6H) were the principal determinants of res istance to stripe rust. Two-locus QTL interactions were significant determi nants of resistance to this disease. Resistance to the MAV and PAV serotype s of BYDV was determined by coincident QTLs on chromosomes 1 (7H), 4 (4H), and 5 (1H), QTL interactions were not significant fur BYDV resistance. The associations of molecular markers with qualitative and quantitative disease resistance loci will be a useful information for marker-assisted selection .