Genetic variability in light-related parameters of maize models revealed by linking 3D-reconstruction of plant architecture with light model and phenotyping platform

TSU-WEI CHEN; CHRISTIAN FOURNIER; SIMON ARTZET; NICOLAS BRICHET; JÉRÔME CHOPARD; CHRISTOPHE PRADAL; SANTIAGO ALVAREZ PRADO; LLORENÇ CABRERA-BOSQUET; CLAUDE WELCKER; FRANÇOIS TARDIEU

Qingdao

Congreso; 2016 IEEE International Conference on Functional-Structural Plant Growth Modeling, Simulation, Visualization and Applications (FSPMA 2016); 2016

Radiation interception efficiency(RIE) and radiation use efficiency (RUE) are the main driving forces of drymass accumulation, so parameters related to RIE and RUE, e.g. light extinction coefficient(k) and photosynthetic parameters, havestrong impacts on yields. Since these parameters are strongly related to thecanopy structure, architectural traits of plants are important for characterizationof the genetic variability of these parameters, a critical work for modelling theinteractions between yield and environmental conditions and predicting future geneticgain. In this work, we propose a new method to estimate the RIE- and RUE-relatedparameters of maize for the crop models by a high-throughput phenotyping platform,PHENOARCH (https://goo.gl /x3C6oN).In autumn 2014, 330 maize lines were grown under non-stressed condition withfive repetitions. For each plant, one top image and 12 side images of the plantwere taken every 2-3 days. These images were used to reconstruct the 3D-architectureof the plants. To estimate RIE of a maize line on day t, the 3D plants of this line were used for constructing a virtualcanopy consisting of 15 plants in three rows. Based on the architecture of thisvirtual canopy, RIE was calculated by the RATP light model and leaf area index(LAI) was estimated by the images analyses and the reconstructed 3D-architecture.k was obtained by computing the slopebetween natural logarithm oflight transmittance through the canopy and LAI. Relationship between RIEand plant developmental stage was fitted to a sigmoidal function with threeparameters: maximum RIE (RIEmax), maximum change of RIE (smax) and time taken to reachsmax (ts). Maize lines were genotyped with 354K polymorphicSNPs and genome wide association analysis (GWAS) was performed over modelparameters. Between genotypes, significant differences in k, RIEmax, smaxand ts were found, rangingfrom 0.31-0.75 (unitless), 0.43-0.98 (unitless), 0.12-0.27 (d-1) and18.3-39.5 (d), respectively. GWASrevealed 16 QTL for k, 77 for RIEmax,1 for smax and 7 for ts. This study is anexample of model-assisted phenotyping and we conclude that using the 3Darchitecture of plants reconstructed by phenotyping platform has strongpotential to discover the genetic variability of light-related traits. Furtherpossibilities include the estimation of radiation use efficiency and relativecanopy photosynthetic capacity.