title: Genetic basis of nitrogen use efficiency and yield stability across environments in winter rapeseed.
abstract: Nitrogen use efficiency is an important breeding trait that can be modified to improve the sustainability of many crop species used in agriculture. Rapeseed is a major oil crop with low nitrogen use efficiency, making its production highly dependent on nitrogen input. This complex trait is suspected to be sensitive to genotype × environment interactions, especially genotype × nitrogen interactions. Therefore, phenotyping diverse rapeseed populations under a dense network of trials is a powerful approach to study nitrogen use efficiency in this crop. The present study aimed to determine the quantitative trait loci (QTL) associated with yield in winter oilseed rape and to assess the stability of these regions under contrasting nitrogen conditions for the purpose of increasing nitrogen use efficiency.
  
  
  
  Genome-wide association studies and linkage analyses were performed on two diversity sets and two doubled-haploid populations. These populations were densely genotyped, and yield-related traits were scored in a multi-environment design including seven French locations, six growing seasons (2009 to 2014) and two nitrogen nutrition levels (optimal versus limited). Very few genotype × nitrogen interactions were detected, and a large proportion of the QTL were stable across nitrogen nutrition conditions. In contrast, strong genotype × trial interactions in which most of the QTL were specific to a single trial were found. To obtain further insight into the QTL × environment interactions, genetic analyses of ecovalence were performed to identify the genomic regions contributing to the genotype × nitrogen and genotype × trial interactions. Fifty-one critical genomic regions contributing to the additive genetic control of yield-associated traits were identified, and the structural organization of these regions in the genome was investigated.
  
  
  
  Our results demonstrated that the effect of the trial was greater than the effect of nitrogen nutrition levels on seed yield-related traits under our experimental conditions. Nevertheless, critical genomic regions associated with yield that were stable across environments were identified in rapeseed.
authors.affiliation: INRA, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Bouchet
authors.affiliation: AGROCAMPUS OUEST, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France. anne.laperche@agrocampus-ouest.fr.
authors.forename: Anne
authors.initials: A
authors.lastname: Laperche
authors.affiliation: AGROCAMPUS OUEST, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Bissuel-Belaygue
authors.affiliation: INRA, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Baron
authors.affiliation: INRA, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Morice
authors.affiliation: INRA, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Rousseau-Gueutin
authors.affiliation: Limagrain Europe, Ferme de l'Etang, 77390, Verneuil-l'Etang, France.
authors.forename: Jean-Eric
authors.initials: JE
authors.lastname: Dheu
authors.affiliation: Biogemma, Chemin de Panedautes, 31700, Mondonville, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: George
authors.affiliation: Terres Inovia, Avenue Lucien Brétignières, 78850, Thiverval Grignon, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Pinochet
authors.affiliation: Euralis, Chemin de Panedautes, 31700, Mondonville, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Foubert
authors.affiliation: Maisadour Semences, Route de Saint Sever, BP27, 40001, Mont de Marsan Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Maes
authors.affiliation: RAGT R2n, Rue Emile Singla, BP 3331, 12033, Rodez, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Dugué
authors.affiliation: Syngenta, Chemin de l'Hobit, 31790, Saint-Sauveur, France.
authors.forename: Florent
authors.initials: F
authors.lastname: Guinot
authors.affiliation: INRA, UMR 1349 IGEPP, BP 35327, 35650, le Rheu, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Nesi
mesh_terms: D000465:Algorithms; D005075:Biological Evolution; D029741:Brassica rapa / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D016000:Cluster Analysis; D004734:Energy Metabolism / Q000235:genetics*; D059647:Gene-Environment Interaction; D056726:Genetic Association Studies; D008040:Genetic Linkage; D018745:Genome, Plant; D055106:Genome-Wide Association Study; D023281:Genomics / Q000379:methods; D005838:Genotype; D015233:Models, Statistical; D009584:Nitrogen / Q000378:metabolism*; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D012621:Seasons
chemical_list: D009584:Nitrogen
keywords: Brassica napus L; Ecovalence; Genotype × nitrogen interactions; Nitrogen stress; Quantitative trait loci