title: Multispectral airborne imagery in the field reveals genetic determinisms of morphological and transpiration traits of an apple tree hybrid population in response to water deficit.
abstract: Genetic studies of response to water deficit in adult trees are limited by low throughput of the usual phenotyping methods in the field. Here, we aimed at overcoming this bottleneck, applying a new methodology using airborne multispectral imagery and in planta measurements to compare a high number of individuals.An apple tree population, grafted on the same rootstock, was submitted to contrasting summer water regimes over two years. Aerial images acquired in visible, near- and thermal-infrared at three dates each year allowed calculation of vegetation and water stress indices. Tree vigour and fruit production were also assessed. Linear mixed models were built accounting for date and year effects on several variables and including the differential response of genotypes between control and drought conditions.Broad-sense heritability of most variables was high and 18 quantitative trait loci (QTLs) independent of the dates were detected on nine linkage groups of the consensus apple genetic map. For vegetation and stress indices, QTLs were related to the means, the intra-crown heterogeneity, and differences induced by water regimes. Most QTLs explained 15-20% of variance.Airborne multispectral imaging proved relevant to acquire simultaneous information on a whole tree population and to decipher genetic determinisms involved in response to water deficit.
authors.affiliation: Montpellier SupAgro, UMR AGAP 1334, TA-A-108/03, Av. Agropolis, 34398 Montpellier Cedex 5, France Present address: PCBS Department, Rothamsted Research, Harpenden, AL5 2JQ, UK.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Virlet
authors.affiliation: INRA, UMR AGAP 1334, TA-A-108/03, Av. Agropolis, 34398 Montpellier Cedex 5, France.
authors.forename: Evelyne
authors.initials: E
authors.lastname: Costes
authors.affiliation: INRA, UMR AGAP 1334, TA-A-108/03, Av. Agropolis, 34398 Montpellier Cedex 5, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Martinez
authors.affiliation: Montpellier SupAgro, UMR AGAP 1334, TA-A-108/03, Av. Agropolis, 34398 Montpellier Cedex 5, France.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Kelner
authors.affiliation: Montpellier SupAgro, UMR AGAP 1334, TA-A-108/03, Av. Agropolis, 34398 Montpellier Cedex 5, France jean-luc.regnard@supagro.fr.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Regnard
mesh_terms: D055864:Droughts; D005638:Fruit / Q000254:growth & development; D008040:Genetic Linkage; D027845:Malus / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D018526:Plant Transpiration; D040641:Quantitative Trait Loci; D058998:Remote Sensing Technology / Q000379:methods*; D012621:Seasons; D014197:Trees / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water
keywords: Malus×domestica; multispectral imagery; quantitative trait locus (QTL); surface temperature; thermal infrared; vegetation index.