title: Mapping of common bunt resistance gene Bt9 in wheat.
abstract: The Bt9 resistance locus was mapped and shown to be distinct from the Bt10 locus. New markers linked to Bt9 have been identified and may be used to breed for resistance towards the seed-borne disease. Increasing organic wheat production in Denmark, and in other wheat-producing areas, in conjunction with legal requirements for organic seed production, may potentially lead to a rise in common bunt occurrence. As systemic pesticides are not used in organic farming, organic wheat production systems may benefit from genetic resistances. However, little is known about the underlying genetic mechanisms and locations of the resistance factors for common bunt resistance in wheat. A double haploid (DH) population segregating for common bunt resistance was used to identify the chromosomal location of common bunt resistance gene Bt9. DH lines were phenotyped in three environments and genotyped with DArTseq and SSR markers. The total length of the resulting linkage map was 2882 cM distributed across all 21 wheat chromosomes. Bt9 was mapped to the distal end of chromosome 6DL. Since wheat common bunt resistance gene Bt10 is also located on chromosome 6D, the possibility of their co-location was investigated. A comparison of marker sequences linked to Bt9 and Bt10 on physical maps of chromosome 6D confirmed that Bt9 and Bt10 are two distinct resistance factors located at the distal (6DL) and proximal (6DS) end, respectively, of chromosome 6D. Five new SSR markers Xgpw4005-1, Xgpw7433, Xwmc773, Xgpw7303 and Xgpw362 and many SNP and PAV markers flanking the Bt9 resistance locus were identified and they may be used in the future for marker-assisted selection.
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.|KWS LOCHOW GMBH, Ferdinand-von-Lochow-Straße 5, 29303, Mons, Germany.
authors.forename: Philipp Matthias
authors.initials: PM
authors.lastname: Steffan
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Torp
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.|Agrologica, Houvej 55, 9550, Mariager, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Borgen
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.|Department of Organic Agricultural Sciences, University of Kassel, Nordbahnhofstraße 1a, 37213, Witzenhausen, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Backes
authors.affiliation: Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark. skr@plen.ku.dk.
authors.forename: Søren K
authors.identifier: http://orcid.org/0000-0001-6169-2504
authors.initials: SK
authors.lastname: Rasmussen
mesh_terms: D001487:Basidiomycota; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D006238:Haploidy; D018895:Microsatellite Repeats; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D040641:Quantitative Trait Loci; D014908:Triticum / Q000235:genetics*
chemical_list: D005819:Genetic Markers