title: Genetic dissection of heterosis using epistatic association mapping in a partial NCII mating design.
abstract: Heterosis refers to the phenomenon in which an F1 hybrid exhibits enhanced growth or agronomic performance. However, previous theoretical studies on heterosis have been based on bi-parental segregating populations instead of F1 hybrids. To understand the genetic basis of heterosis, here we used a subset of F1 hybrids, named a partial North Carolina II design, to perform association mapping for dependent variables: original trait value, general combining ability (GCA), specific combining ability (SCA) and mid-parental heterosis (MPH). Our models jointly fitted all the additive, dominance and epistatic effects. The analyses resulted in several important findings: 1) Main components are additive and additive-by-additive effects for GCA and dominance-related effects for SCA and MPH, and additive-by-dominant effect for MPH was partly identified as additive effect; 2) the ranking of factors affecting heterosis was dominance > dominance-by-dominance > over-dominance > complete dominance; and 3) increasing the proportion of F1 hybrids in the population could significantly increase the power to detect dominance-related effects, and slightly reduce the power to detect additive and additive-by-additive effects. Analyses of cotton and rapeseed datasets showed that more additive-by-additive QTL were detected from GCA than from trait phenotype, and fewer QTL were from MPH than from other dependent variables.
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.|State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wen
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Xinwang
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Guorong
authors.initials: G
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xiang
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Su-Hong
authors.initials: SH
authors.lastname: Bu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Can
authors.initials: C
authors.lastname: Yi
authors.affiliation: Soybean Genomics and Improvement Laboratory, Agricultural Research Service, United States Department of Agriculture, Maryland 20705, USA.
authors.forename: Qijian
authors.initials: Q
authors.lastname: Song
authors.affiliation: School of Agriculture, Policy and Development, University of Reading, Reading RG6 6AS, United Kingdom.
authors.forename: Jim M
authors.initials: JM
authors.lastname: Dunwell
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Jinxing
authors.initials: J
authors.lastname: Tu
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Tianzhen
authors.initials: T
authors.lastname: Zhang
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Yuan-Ming
authors.initials: YM
authors.lastname: Zhang
mesh_terms: D029741:Brassica rapa / Q000235:genetics; D004843:Epistasis, Genetic; D006823:Hybrid Vigor / Q000235:genetics*; D015810:Linkage Disequilibrium; D008957:Models, Genetic; D009010:Monte Carlo Method; D010641:Phenotype; D040641:Quantitative Trait Loci