title: The genetic architecture of grain yield and related traits in Zea maize L. revealed by comparing intermated and conventional populations.
abstract: Using advanced intermated populations has been proposed as a way to increase the accuracy of mapping experiments. An F(3) population of 300 lines and an advanced intermated F(3) population of 322 lines, both derived from the same parental maize inbred lines, were jointly evaluated for dry grain yield (DGY), grain moisture (GM), and silking date (SD). Genetic variance for dry grain yield was significantly lower in the intermated population compared to the F(3) population. The confidence interval around a QTL was on average 2.31 times smaller in the intermated population compared to the F(3) population. One controversy surrounding QTL mapping is whether QTL identified in fact represent single loci. This study identifies two distinct loci for dry grain yield in the intermated population in coupling phase, while the F(3) identifies only a single locus. Surprisingly, fewer QTL were detected in the intermated population than the F(3) (21 vs. 30) and <50% of the detected QTL were shared among the two populations. Cross-validation showed that selection bias was more important in the intermated population than in the F(3) and that each detected QTL explained a lower percentage of the variance. This finding supports the hypothesis that QTL detected in conventional populations correspond mainly to clusters of linked QTL. The actual number of QTL involved in the genetic architecture of complex traits may be substantially larger, with effect sizes substantially smaller than in conventional populations.
authors.affiliation: Institut National de Recherche Agronomique, UMR 0320/UMR 8120 Génétique Végétale, F-91190 Gif-sur-Yvette, France.
authors.forename: Yung-Fen
authors.initials: YF
authors.lastname: Huang
authors.forename: Delphine
authors.initials: D
authors.lastname: Madur
authors.forename: Valérie
authors.initials: V
authors.lastname: Combes
authors.forename: Chin Long
authors.initials: CL
authors.lastname: Ky
authors.forename: Denis
authors.initials: D
authors.lastname: Coubriche
authors.forename: Philippe
authors.initials: P
authors.lastname: Jamin
authors.forename: Sophie
authors.initials: S
authors.lastname: Jouanne
authors.forename: Fabrice
authors.initials: F
authors.lastname: Dumas
authors.forename: Ellen
authors.initials: E
authors.lastname: Bouty
authors.forename: Pascal
authors.initials: P
authors.lastname: Bertin
authors.forename: Alain
authors.initials: A
authors.lastname: Charcosset
authors.forename: Laurence
authors.initials: L
authors.lastname: Moreau
mesh_terms: D002874:Chromosome Mapping; D002523:Edible Grain / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D005838:Genotype; D006824:Hybridization, Genetic / Q000235:genetics*; D010641:Phenotype; D040641:Quantitative Trait Loci / Q000235:genetics; D015203:Reproducibility of Results; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D014867:Water