title: Screening for drought tolerance of maize hybrids by multi-scale analysis of root and shoot traits at the seedling stage.
abstract: We studied the drought response of eight commercial hybrid maize lines with contrasting drought sensitivity together with the reference inbred line B73 using a non-invasive platform for root and shoot phenotyping and a kinematics approach to quantify cell level responses in the leaf. Drought treatments strongly reduced leaf growth parameters including projected leaf area, elongation rate, final length and width of the fourth and fifth leaf. Physiological measurements including water use efficiency, chlorophyll fluorescence and photosynthesis were also significantly affected. By performing a kinematic analysis, we show that leaf growth reduction in response to drought is mainly due to a decrease in cell division rate, whereas a marked reduction in cell expansion rate is compensated by increased duration of cell expansion. Detailed analysis of root growth in rhizotrons under drought conditions revealed a strong reduction in total root length as well as rooting depth and width. This was reflected by corresponding decreases in fresh and dry weight of the root system. We show that phenotypic differences between lines differing in geographic origin (African vs. European) and in drought tolerance under field conditions can already be identified at the seedling stage by measurements of total root length and shoot dry weight of the plants. Moreover, we propose a list of candidate traits that could potentially serve as traits for future screening strategies.
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerpen, Belgium.
authors.forename: Viktoriya
authors.initials: V
authors.lastname: Avramova
authors.affiliation: IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
authors.forename: Kerstin A
authors.initials: KA
authors.lastname: Nagel
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerpen, Belgium.
authors.forename: Hamada
authors.initials: H
authors.lastname: AbdElgawad
authors.affiliation: Instituto de Investgatión de Fisiología y Recursos Genéticos Vegetales, Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), X5020ICA Cordoba, Argentina.
authors.forename: Dolores
authors.initials: D
authors.lastname: Bustos
authors.affiliation: Department of Plant Production and Soil Science, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, South Africa.
authors.forename: Magdeleen
authors.initials: M
authors.lastname: DuPlessis
authors.affiliation: IBG-2: Plant Sciences, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
authors.forename: Fabio
authors.initials: F
authors.lastname: Fiorani
authors.affiliation: Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerpen, Belgium gerrit.beemster@uantwerpen.be.
authors.forename: Gerrit T S
authors.identifier: http://orcid.org/0000-0001-6014-053X
authors.initials: GT
authors.lastname: Beemster
mesh_terms: D000222:Adaptation, Physiological; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D055864:Droughts; D006824:Hybridization, Genetic; D010641:Phenotype; D018517:Plant Roots / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D018520:Plant Shoots / Q000254:growth & development / Q000502:physiology*; D030821:Plants, Genetically Modified; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D036226:Seedlings / Q000502:physiology*; D003313:Zea mays / Q000235:genetics / Q000502:physiology*
keywords: Kinematics; leaf growth; phenotyping; rhizotron; root growth; water deficiency.