title: Genome-wide linkage mapping of QTL for black point reaction in bread wheat (Triticum aestivum L.).
abstract: Nine QTL for black point resistance in wheat were identified using a RIL population derived from a Linmai 2/Zhong 892 cross and 90K SNP assay. Black point, discoloration of the embryo end of the grain, downgrades wheat grain quality leading to significant economic losses to the wheat industry. The availability of molecular markers will accelerate improvement of black point resistance in wheat breeding. The aims of this study were to identify quantitative trait loci (QTL) for black point resistance and tightly linked molecular markers, and to search for candidate genes using a high-density genetic linkage map of wheat. A recombinant inbred line (RIL) population derived from the cross Linmai 2/Zhong 892 was evaluated for black point reaction during the 2011-2012, 2012-2013 and 2013-2014 cropping seasons, providing data for seven environments. A high-density linkage map was constructed by genotyping the RILs with the wheat 90K single nucleotide polymorphism (SNP) chip. Composite interval mapping detected nine QTL on chromosomes 2AL, 2BL, 3AL, 3BL, 5AS, 6A, 7AL (2) and 7BS, designated as QBp.caas-2AL, QBp.caas-2BL, QBp.caas-3AL, QBp.caas-3BL, QBp.caas-5AS, QBp.caas-6A, QBp.caas-7AL.1, QBp.caas-7AL.2 and QBp.caas-7BS, respectively. All resistance alleles, except for QBp.caas-7AL.1 from Linmai 2, were contributed by Zhong 892. QBp.caas-3BL, QBp.caas-5AS, QBp.caas-7AL.1, QBp.caas-7AL.2 and QBp.caas-7BS probably represent new loci for black point resistance. Sequences of tightly linked SNPs were used to survey wheat and related cereal genomes identifying three candidate genes for black point resistance. The tightly linked SNP markers can be used in marker-assisted breeding in combination with the kompetitive allele specific PCR technique to improve black point resistance.
authors.affiliation: Institute of Crop Science, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences (CAAS), 12 Zhongguancun South Street, Beijing, 100081, China.|Department of Plant Genetics and Breeding, State Key Laboratory for Agrobiotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, China.
authors.forename: Jindong
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute of Crop Science, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences (CAAS), 12 Zhongguancun South Street, Beijing, 100081, China.|International Maize and Wheat Improvement Center (CIMMYT) China Office, c/o CAAS, 12 Zhongguancun South Street, Beijing, 100081, China.
authors.forename: Zhonghu
authors.initials: Z
authors.lastname: He
authors.affiliation: Crop Research Institute, Sichuan Academy of Agricultural Sciences, 20 Jingjusi Road, Chengdu, 610066, Sichuan, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Wu
authors.affiliation: Wheat Research Institute, Gansu Academy of Agricultural Sciences, Lanzhou, 730070, Gansu, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Bai
authors.affiliation: Institute of Crop Science, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences (CAAS), 12 Zhongguancun South Street, Beijing, 100081, China.
authors.forename: Weie
authors.initials: W
authors.lastname: Wen
authors.affiliation: Department of Plant Genetics and Breeding, State Key Laboratory for Agrobiotechnology, China Agricultural University, 2 Yuanmingyuan West Road, Beijing, 100193, China.
authors.forename: Chaojie
authors.initials: C
authors.lastname: Xie
authors.affiliation: Institute of Crop Science, National Wheat Improvement Center, Chinese Academy of Agricultural Sciences (CAAS), 12 Zhongguancun South Street, Beijing, 100081, China. xiaxianchun@caas.cn.
authors.forename: Xianchun
authors.initials: X
authors.lastname: Xia
mesh_terms: D000483:Alleles; D002874:Chromosome Mapping; D060467:Disease Resistance / Q000235:genetics*; D008040:Genetic Linkage; D005838:Genotype; D008126:Lod Score; D010935:Plant Diseases / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D014908:Triticum / Q000235:genetics*