title: Genotypic differences in architectural and physiological responses to water restriction in rose bush.
abstract: The shape and, therefore, the architecture of the plant are dependent on genetic and environmental factors such as water supply. The architecture determines the visual quality, a key criterion underlying the decision to purchase an ornamental potted plant. The aim of this study was to analyze genotypic responses of eight rose bush cultivars to alternation of water restriction and re-watering periods, with soil water potential of -20 and -10 kPa respectively. Responses were evaluated at the architectural level through 3D digitalization using six architectural variables and at the physiological level by measuring stomatal conductance, water content, hormones [abscisic acid (ABA), auxin, cytokinins, jasmonic acid, and salicylic acid (SA)], sugars (sucrose, fructose, and glucose), and proline. Highly significant genotype and watering effects were revealed for all the architectural variables measured, as well as genotype × watering interaction, with three distinct genotypic architectural responses to water restriction - weak, moderate and strong - represented by Hw336, 'Baipome' and 'The Fairy,' respectively. The physiological analysis explained, at least in part, the more moderate architectural response of 'Baipome' compared to 'The Fairy,' but not that of Hw336 which is an interspecific hybrid. Such physiological responses in 'Baipome' could be related to: (i) the maintenance of the stimulation of budbreak and photosynthetic activity during water restriction periods due to a higher concentration in conjugated cytokinins (cCK) and to a lower concentration in SA; (ii) a better resumption of budbreak during the re-watering periods due to a lower concentration in ABA during this period. When associated with the six architectural descriptors, cCK, SA and ABA, which explained the genotypic differences in this study, could be used as selection criteria for breeding programs aimed at improving plant shape and tolerance to water restriction.
authors.affiliation: ASTREDHOR - Institut Technique de l'Horticulture, Paris France ; Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences (INRA-Agrocampus Ouest-Université d'Angers), Angers France.
authors.forename: Camille
authors.initials: C
authors.lastname: Li-Marchetti
authors.affiliation: Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences (INRA-Agrocampus Ouest-Université d'Angers), Angers France.
authors.forename: Camille
authors.initials: C
authors.lastname: Le Bras
authors.affiliation: Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences (INRA-Agrocampus Ouest-Université d'Angers), Angers France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Relion
authors.affiliation: INRA, Institut Jean-Pierre Bourgin Centre de Versailles-Grignon, Unité Mixte de Recherche 1318 (INRA-Agro-ParisTech-CNRS), Versailles France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Citerne
authors.affiliation: INRA, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, (INRA-Agrocampus Ouest-Université d'Angers), Beaucouzé France.
authors.forename: Lydie
authors.initials: L
authors.lastname: Huché-Thélier
authors.affiliation: Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences (INRA-Agrocampus Ouest-Université d'Angers), Angers France.
authors.forename: Soulaiman
authors.initials: S
authors.lastname: Sakr
authors.affiliation: INRA, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, (INRA-Agrocampus Ouest-Université d'Angers), Beaucouzé France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Morel
authors.affiliation: INRA, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, (INRA-Agrocampus Ouest-Université d'Angers), Beaucouzé France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Crespel
keywords: Rosa; architectural analysis; genotype × environment interaction; hormones; water restriction tolerance