title: Association mapping of quantitative resistance to Phaeosphaeria nodorum in spring wheat landraces from the USDA National Small Grains Collection.
abstract: Stagonospora nodorum blotch (SNB), caused by Phaeosphaeria nodorum, is a destructive disease of wheat (Triticum aestivum) found throughout the United States. Host resistance is the only economically feasible option for managing the disease; however, few SNB-resistant wheat cultivars are known to exist. In this study, we report findings from an association mapping (AM) of resistance to P. nodorum in 567 spring wheat landraces of diverse geographic origin. The accessions were evaluated for seedling resistance to P. nodorum in a greenhouse. Phenotypic data and 625 polymorphic diversity array technology (DArT) markers have been used for linkage disequilibrium (LD) and association analyses. The results showed that seven DArT markers on five chromosomes (2D, 3B, 5B, 6A, and 7A) were significantly associated with resistance to P. nodorum. Genetic regions on 2D, 3B, and 5B correspond to previously mapped quantitative trait loci (QTL) conferring resistance to P. nodorum whereas the remaining QTL appeared to be novel. These results demonstrate that the use of AM is an effective method for identifying new genomic regions associated with resistance to P. nodorum in spring wheat landraces. Additionally, the novel resistance found in this study could be useful in wheat breeding aimed at controlling SNB.
authors.affiliation: Department of Plant Pathology, North Dakota State University, Frago, ND, USA. tika.adhikari@ndsu.edu
authors.forename: Tika B
authors.initials: TB
authors.lastname: Adhikari
authors.forename: Eric W
authors.initials: EW
authors.lastname: Jackson
authors.forename: Suraj
authors.initials: S
authors.lastname: Gurung
authors.forename: Jana M
authors.initials: JM
authors.lastname: Hansen
authors.forename: J Michael
authors.initials: JM
authors.lastname: Bonman
mesh_terms: D000483:Alleles; D001203:Ascomycota / Q000276:immunology* / Q000502:physiology; D001947:Breeding; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D005838:Genotype; D015810:Linkage Disequilibrium; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*; D036226:Seedlings / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D014908:Triticum / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D014481:United States; D016885:United States Department of Agriculture
chemical_list: D005819:Genetic Markers