title: A haplotype block associated with thousand-kernel weight on chromosome 5DS in common wheat (Triticum aestivum L.).
abstract: Spike number per unit area, number of grains per spike, and thousand-kernel weight (TKW) are important yield components for wheat (Triticum aestivum L.). TKW has the highest heritability among the three components. We validated 27 simple sequence repeat (SSR) loci associated with TKW in an F(2:5) breeding population grown in four environments. A cfd7(8265bp) marker on chromosome 5DS showed the strongest association with TKW and had a significantly positive effect on TKW compared to allele cfd7(8259bp), with mean increases of 5.17, 3.63, 4.11, and 5.16 g in the four environments. Markers cfd67 and cfd40 flanking cfd78 also showed significantly positive associations with TKW with increases of 5.11, 3.29, 4.31, and 4.50 g for cfd67(205), and 4.98, 3.49, 4.06, and 4.84 g for cfd40(187) compared with cfd67(203) and cfd40(190) in the four environments, respectively. A major quantitative trait locus for TKW spanning 2.94 cM on chromosome 5DS was detected by association mapping. Strong linkage disequilibrium (LD) (r(2)  > 0.2) was detected among the three linked markers, which formed three haplotype blocks in the F(2:5) breeding population. Mean TKW differences between HapB-I and HapB-II were 5.80, 4.41, 4.02, and 5.06 g in the four environments, respectively. Moreover, significant LD was detected only between cfd78 and cfd67 and between cfd67 and cfd40 in a germplasm collection. This study provides a base for cloning genes related to TKW on chromosome 5DS.
authors.affiliation: Crop Genomics and Bioinformatics Center and National Key Lab of Crop Genetics and Germplasm Enhancement, College of Agricultural Sciences, Nanjing Agricultural University, Nanjing, 210095, China.|Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Yuquan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Hao
authors.affiliation: Crop Genomics and Bioinformatics Center and National Key Lab of Crop Genetics and Germplasm Enhancement, College of Agricultural Sciences, Nanjing Agricultural University, Nanjing, 210095, China.|Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Ge
authors.affiliation: Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Crop Genomics and Bioinformatics Center and National Key Lab of Crop Genetics and Germplasm Enhancement, College of Agricultural Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Zhengqiang
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Crop Genomics and Bioinformatics Center and National Key Lab of Crop Genetics and Germplasm Enhancement, College of Agricultural Sciences, Nanjing Agricultural University, Nanjing, 210095, China.|Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/Institute of Crop Science, the Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Xueyong
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000483:Alleles; D001947:Breeding; D032461:Chromosomes, Plant / Q000235:genetics*; D004777:Environment; D056726:Genetic Association Studies; D056426:Genetic Loci; D005819:Genetic Markers; D006239:Haplotypes / Q000235:genetics*; D015810:Linkage Disequilibrium / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics; D010641:Phenotype; D011110:Polymorphism, Genetic; D015203:Reproducibility of Results; D014908:Triticum / Q000235:genetics*
chemical_list: D005819:Genetic Markers
keywords: Association mapping; Triticum aestivum; haplotype; thousand-kernel weight