title: Analysis of the chromosome 2(2H) region of barley associated with the correlated traits Fusarium head blight resistance and heading date.
abstract: Fusarium head blight (FHB) is a major disease of barley (Hordeum vulgare L.) that results in reduced grain yield and quality through the accumulation of the mycotoxin deoxynivalenol (DON). Coincident QTL for FHB severity, DON concentration, and heading date (HD) map to a region of chromosome 2(2H) designated Qrgz-2H-8. It is unclear whether disease resistance at this locus is due to a pleiotropic effect of late HD by delaying the host exposure to the pathogen or a tightly linked resistance gene. The objectives of this study were to develop a set of near isogenic lines (NILs) for the Qrgz-2H-8 region and to genetically dissect the QTL region containing the coincident traits. Two NIL populations were developed consisting of F(2)- and F(4)-derived recombinants from a cross between a BC(5) line carrying the donor parent (Chevron) alleles in the Qrgz-2H-8 region and the recurrent parent M69. Analysis of field and marker data from these NILs revealed that the Chevron alleles conditioning FHB resistance, late HD, and low DON concentration were successfully introgressed into the BC(5) parent line and were segregating among NILs. QTL analysis of the F(4)-derived population showed that the HD QTL is adjacent to the FHB QTL. Furthermore, a single NIL was identified that was similar to the resistant BC(5) parent for FHB severity and the early flowering parent M69 for HD. These results indicate that the relationship between FHB and HD at the Qrgz-2H-8 region is likely due to tight linkage rather than pleiotropy.
authors.affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, Rm 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Nduulu
authors.forename: A
authors.initials: A
authors.lastname: Mesfin
authors.forename: G J
authors.initials: GJ
authors.lastname: Muehlbauer
authors.forename: K P
authors.initials: KP
authors.lastname: Smith
mesh_terms: D000483:Alleles; D001947:Breeding; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D005670:Fusarium / Q000472:pathogenicity*; D008040:Genetic Linkage; D006239:Haplotypes; D001467:Hordeum / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology*; D009183:Mycotoxins / Q000633:toxicity; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D030821:Plants, Genetically Modified; D040641:Quantitative Trait Loci; D014255:Trichothecenes / Q000633:toxicity
chemical_list: D018744:DNA, Plant; D009183:Mycotoxins; D014255:Trichothecenes; C007262:deoxynivalenol