title: Development of a multiple-hybrid population for genome-wide association studies: theoretical consideration and genetic mapping of flowering traits in maize.
abstract: Various types of populations have been used in genetics, genomics and crop improvement, including bi- and multi-parental populations and natural ones. The latter has been widely used in genome-wide association study (GWAS). However, inbred-based GWAS cannot be used to reveal the mechanisms involved in hybrid performance. We developed a novel maize population, multiple-hybrid population (MHP), consisting of 724 hybrids produced using 28 temperate and 23 tropical inbreds. The hybrids can be divided into three subpopulations, two diallels and NC (North Carolina Design) II. Significant genetic differences were identified among parents, hybrids and heterotic groups. A cluster analysis revealed heterotic groups existing in the parental lines and the results showed that MHPs are well suitable for GWAS in hybrid crops. MHP-based GWAS was performed using 55 K SNP array for flowering time traits, days to tassel, days to silk, days to anthesis and anthesis-silking interval. Two independent methods, PEPIS developed for hybrids and TASSEL software designed for inbred line populations, revealed highly consistent results with five overlapping chromosomal regions identified and used for discovery of candidate genes and quantitative trait nucleotides. Our results indicate that MHPs are powerful in GWAS for hybrid-related traits with great potential applications in the molecular breeding era.
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Xu
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Zifeng
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Xu
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Shanhong
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Chuanxiao
authors.initials: C
authors.lastname: Xie
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Wen-Xue
authors.initials: WX
authors.lastname: Li
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Zou
authors.affiliation: Institute of Crop Science, National Key Facility of Crop Gene Resources and Genetic Improvement, Chinese Academy of Agricultural Sciences, Beijing 100081, China.|International Maize and Wheat Improvement Center (CIMMYT), El Batán 56130, Texcoco, Mexico.
authors.forename: Yunbi
authors.initials: Y
authors.lastname: Xu
mesh_terms: D002678:Chimera / Q000235:genetics*; D002874:Chromosome Mapping; D000069599:Crop Production; D017343:Genes, Plant; D055106:Genome-Wide Association Study; D005838:Genotype; D006823:Hybrid Vigor; D010641:Phenotype; D003313:Zea mays / Q000235:genetics*