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.

Trait components of whole plant water use efficiency are defined by unique, environmentally responsive genetic signatures in the model C4grassSetaria

“…Strong correlation between plant size and water use was observed in spite of the fact that these traits can potentially be controlled by different physiological mechanisms. A similar trend has also been described in experiments designed to study water use efficiency in Arabidopsis thaliana , apple and wheat (Lopez et al, 2015; Nakhforoosh et al, 2016; Schoppach et al, 2016; Parent et al, 2015; Vasseur et al, 2014). The magnitude of this correlation is likely inflated in this study due to the large differences in size between parental lines and segregants within the A10 x B100 RIL population.…”

“…Automated or manual gravimetric measurement of pot weight has proven to be a reliable estimator of plant transpiration but only if the evaporative loss of moisture from soil can be accounted for. Results presented in this study indicate that inclusion of empty pots (or pots that contain plastic plants (Parent et al, 2015) or fabric wicks (Halperin et al, 2017)) is an appropriate empirical method to estimate the experimental time point at which transpiration contributes meaningfully to total pot evapotranspiration (Coupel-Ledru et al, 2016; Lopez et al, 2015; Pereyra-Irujo et al, 2012). Estimation of evapotranspiration after this critical time point has been effectively used by several other groups to identify and eliminate confounding data points collected early during similar experiments (Vasseur et al, 2014; Coupel-Ledru et al, 2016; Ge et al, 2016).…”

“…This was achieved by modeling plant size as a function of water use and examining the resulting values of the model fit (plant size given water use) and deviations from this relationship (residual of plant size given water use). This linear modeling approach has been used much less frequently in the literature (Lopez et al, 2015; Nakhforoosh et al, 2016) than the more commonly used WUE ratio (Adiredjo et al, 2014; Honsdorf et al, 2014; Aparna et al, 2015; Fahlgren et al, 2015; Lopez et al, 2015). While the genetic architectures associated with the WUE ratio and WUE residual in this population are closely related (Fig.…”

Combining Genome-Wide Information with a Functional Structural Plant Model to Simulate 1-Year-Old Apple Tree Architecture

“…When trees were 3-year-old in Experiment 1, the maximal individual leaf areas along four randomly chosen shoots were measured on each tree at the end of the growing season (end of September 2009). This maximal leaf area has been already observed to be highly heritable and to display lower variability than individual leaf areas along the trunk (Lopez et al, 2015). …”

Phenomenal: An automatic open source library for 3D shoot architecture reconstruction and analysis for image-based plant phenotyping

“…In all experiments, plants were grown in polyvinyl chloride (PVC) 9 L pots (0.19 m diameter, 0.4 m high) filled with a 30:70 (v/v) mixture of a clay and organic compost. Detailed descriptions of most of the experiments can be found in the literature (MA14: Lopez et al, 2015; ZB12, ZA13, ZB13 and ZA16 (Alvarez-Prado et al, 2017); ZA17 (Brichet et al 2017); ZB14 and GA16, unpublished). The PhenoArch image acquisition system takes RGB color images (2056 x 2454 pixels) from the top and the side of the plant (Cabrera-Bosquet et al 2016).…”