title: Deciphering the genetics of flowering time by an association study on candidate genes in bread wheat (Triticum aestivum L.).
abstract: Earliness is very important for the adaptation of wheat to environmental conditions and the achievement of high grain yield. A detailed knowledge of key genetic components of the life cycle would enable an easier control by the breeders. The objective of the study was to investigate the effect of candidate genes on flowering time. Using a collection of hexaploid wheat composed of 235 lines from diverse geographical origins, we conducted an association study for six candidate genes for flowering time and its components (vernalization sensitivity and earliness per se). The effect on the variation of earliness components of polymorphisms within the copies of each gene was tested in ANOVA models accounting for the underlying genetic structure. The collection was structured in five groups that minimized the residual covariance. Vernalization requirement and lateness tend to increase according to the mean latitude of each group. Heading date for an autumnal sowing was mainly determined by the earliness per se. Except for the Constans (CO) gene orthologous of the barley HvCO3, all gene polymorphisms had a significant impact on earliness components. The three traits used to quantify vernalization requirement were primarily associated with polymorphisms at Vrn-1 and then at Vrn-3 and Luminidependens (LD) genes. We found a good correspondence between spring/winter types and genotypes at the three homeologous copies of Vrn-1. Earliness per se was mainly explained by polymorphisms at Vrn-3 and to a lesser extent at Vrn-1, Hd-1 and Gigantea (GI) genes. Vernalization requirement and earliness as a function of geographical origin, as well as the possible role of the breeding practices in the geographical distribution of the alleles and the hypothetical adaptive value of the candidate genes, are discussed.
authors.affiliation: UMR de Génétique Végétale, INRA/CNRS/AgroParisTech/Univ. Paris XI, Ferme du Moulon, 91190 Gif sur Yvette, France. mrousset@moulon.inra.fr
authors.forename: Michel
authors.initials: M
authors.lastname: Rousset
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bonnin
authors.forename: Carine
authors.initials: C
authors.lastname: Remoué
authors.forename: Matthieu
authors.initials: M
authors.lastname: Falque
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Rhoné
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Veyrieras
authors.forename: Delphine
authors.initials: D
authors.lastname: Madur
authors.forename: Alain
authors.initials: A
authors.lastname: Murigneux
authors.forename: François
authors.initials: F
authors.lastname: Balfourier
authors.forename: Jacques
authors.initials: J
authors.lastname: Le Gouis
authors.forename: Sylvain
authors.initials: S
authors.lastname: Santoni
authors.forename: Isabelle
authors.initials: I
authors.lastname: Goldringer
mesh_terms: D000483:Alleles; D001483:Base Sequence; D002874:Chromosome Mapping; D035264:Flowers / Q000235:genetics* / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D056726:Genetic Association Studies; D014644:Genetic Variation; D005838:Genotype; D006239:Haplotypes; D015810:Linkage Disequilibrium; D005810:Multigene Family; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014908:Triticum / Q000235:genetics* / Q000502:physiology*
chemical_list: D010940:Plant Proteins