title: Genetic Variation of Morphological Traits and Transpiration in an Apple Core Collection under Well-Watered Conditions: Towards the Identification of Morphotypes with High Water Use Efficiency.
abstract: Water use efficiency (WUE) is a quantitative measurement which improvement is a major issue in the context of global warming and restrictions in water availability for agriculture. In this study, we aimed at studying the variation and genetic control of WUE and the respective role of its components (plant biomass and transpiration) in a perennial fruit crop. We explored an INRA apple core collection grown in a phenotyping platform to screen one-year-old scions for their accumulated biomass, transpiration and WUE under optimal growing conditions. Plant biomass was decompose into morphological components related to either growth or organ expansion. For each trait, nine mixed models were evaluated to account for the genetic effect and spatial heterogeneity inside the platform. The Best Linear Unbiased Predictors of genetic values were estimated after model selection. Mean broad-sense heritabilities were calculated from variance estimates. Heritability values indicated that biomass (0.76) and WUE (0.73) were under genetic control. This genetic control was lower in plant transpiration with an heritability of 0.54. Across the collection, biomass accounted for 70% of the WUE variability. A Hierarchical Ascendant Classification of the core collection indicated the existence of six groups of genotypes with contrasting morphology and WUE. Differences between morphotypes were interpreted as resulting from differences in the main processes responsible for plant growth: cell division leading to the generation of new organs and cell elongation leading to organ dimension. Although further studies will be necessary on mature trees with more complex architecture and multiple sinks such as fruits, this study is a first step for improving apple plant material for the use of water.
authors.affiliation: Institut National de la Recherche Agronomique, UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales, Campus Cirad, Montpellier, France.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Lopez
authors.affiliation: Institut National de la Recherche Agronomique, UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales, Campus Cirad, Montpellier, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Pallas
authors.affiliation: Institut National de la Recherche Agronomique, UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales, Campus Cirad, Montpellier, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Martinez
authors.affiliation: Institut National de la Recherche Agronomique, UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales, Campus Cirad, Montpellier, France.
authors.forename: Pierre-Éric
authors.initials: PÉ
authors.lastname: Lauri
authors.affiliation: Montpellier SupAgro, UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales, Campus Cirad, Montpellier, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Regnard
authors.affiliation: Institut National de la Recherche Agronomique, UMR Institut de Recherche en Horticulture et Semences, Beaucouzé, France.
authors.forename: Charles-Éric
authors.initials: CÉ
authors.lastname: Durel
authors.affiliation: Institut National de la Recherche Agronomique, UMR Amélioration Génétique et Adaptation des Plantes méditerranéennes et tropicales, Campus Cirad, Montpellier, France.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Costes
mesh_terms: D018533:Biomass; D014644:Genetic Variation / Q000235:genetics*; D005838:Genotype; D027845:Malus / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D010641:Phenotype; D063245:Plant Development / Q000235:genetics*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018526:Plant Transpiration / Q000235:genetics*; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014197:Trees / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014867:Water / Q000378:metabolism*; D060986:Water Wells
chemical_list: D014867:Water