Submitted to: Plant Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/13/1995
Publication Date: N/A
Technical Abstract: Markers locating disease resistance loci can be used for allelism tests and selection. Loci showing Mendelian inheritance can be mapped directly while those showing quantitative inheritance can be mapped as QTL. Because disease resitance loci are often present in upadapted backgrounds, linkage drag and negative pleiotropic effects are of concern. Mapping in a reference population tested in multiple environments allows for detection of coupling and repulsion linkages and coincident QTL, which could either indicate pleiotrophy or tight linkage. We mapped determinants of resistance to the PAV strain of BYDV (barley yellow dwarf virus), leaf rust (Puccinia hordei), stripe rust (Puccinia striiformis), and scald (Rhynchosporium secalis) in a population of doubled haploid lines and related these to effects detected for agronomic and malting quality traits. Determinants of resistance to leaf rust, BYDV, and scald mapped as Mendalian loci to chromosomes 1 and 3, respectively. Determinants of resistance to stripe rust were mapped as QTL to chromosomes 4 and 7 in greenhouse and field tests, respectively. Agronomic and malting quality trait QTL were mapped using data from field environments where these diseases were absent. There were no repulsion linkages, or coincident QTL in a repulsion phase, of resistance loci with agronomic or malting quality traits. QTL for grain yield and two malting quality traits coincided with stripe rust resistance QTL, but the resistant parent contributed favorable alleles. Thus, intra-population manipulation of disease resistance loci can proceed without negative effects on performance. The association of these resistance loci with agronomic and quality traits in other germplasm remains to be determined.