ALPHI®, a Light Arch of Innovative Phenotyping

ALPHI® is an integrated tool that allows crop characterization from acquisition made by imaging or non-imaging sensors. It is an entirely new version of a first prototype developed during the PhenoBlé project (ANR fund, 2010-2013).


This tool was prototyped during PhenoBlé project (ANR fund 2010-2013). ALPHI® is a new version funded by Plant2Pro-Institut Carnot®.
See the Carnot Plant2Pro® video  (in French) and the website.

Technical description

ALPHI® is hitched to a tractor that moves in the direction of the rows of seedlings and embeds the sensors above the vegetation (target crops should be less than 1.3 m). Its double arch allows operators to record two micro-parcels at the same time while the asymmetrical positioning of these arches allows a fluid circulation in the field trial ("Sensors view" picture). The experimental design needs trameline to move around micro-plots.

With its RGB cameras, spectroradiometer and LIDARs, ALPHI® provides information (traits) such as soil cover fraction, green fraction, vegetation index (NDVI, MTCI, MCARI2, etc.), height and leaf angle of the plant. As they are measured without damage to the crop, all these variables can therefore be acquired with a temporal evolution.

Figure : Sensors view from ALPHI®

Main characteristics of Alphi®

Location

Mobile on 1 location per year,
2018 in Chalons en Champagne (North of France)
2019 and later in Villers St Christophe (North of France)

Targets

All thematics, crop < 1.3 m height

Principle of operation

Double measuring head towed or carried

Microplot size

> 2 m long
0.9 to 3 m wide

Number of plots

800 micro plots max
400 micro plots /day

Specificities

Driver and driveway dedicated to the passage of the tractor
Number of passages limited by the ground’s load bearing capacity

On board sensors

RGB cameras, laser light reflection (LIDAR),
Spectroradiometer passive measure

Treatment platform

Signal processing platform developed and maintained by the UMT CAPTE (Avignon)

Example of results

The first prototype of the phenotyping arch was developed within the framework of the PhénoBlé project, funded the ANR led by ARVALIS in collaboration with INRA and Biogemma. This first large-scale project in the field of high-throughput phenotyping began in 2011. Several experiments were carried out to test if this approach was relevant in wheat genotype × Nitrogen experiments. Indeed, Comar et al. 2013 and Gouache et al. 2016 demonstrated that variables like GreenFraction, MCARI2 and MTCI could be linked to N status and yield heritability.


Figure : Green Fraction kinetics measured on a wheat N trial by ALPHI® at the ARVALIS research site of Binas in 2015 (unpublished data).


 

With this first experience, ARVALIS completely revised the tool to make it more robust, more ergonomic and allow it to be fully operational in the field (fund by Plant2Pro-Institut Carnot® in 2017). Then, a new campaign of experiments was carried out in 2015 to assess the sensitivity of the various sensors and variables to discriminate N status × wheat genotype. In the example shown in Green Fraction figure, we observe wheat response to nitrogen fertilizer rate. Green fraction was measured during crop development and allows us to distinguish early growth dynamics and also senescence dynamics. These results could be interpreted by punctual value, curve parameters or area below the curve.

Scientific references

• Comar, A., Burger, P., de Solan, B., Baret, F., Daumard, F., Hanocq, J.-F., 2012. A semi-automatic system for high throughput phenotyping wheat cultivars in-field conditions : description and first results. Functional Plant Biology 39, 914.
• Gouache, D., Beauchêne, K., Mini, A., Fournier, A., de Solan, B., Baret, F., Comar, A., 2016. Applying remote sensing expertise to crop improvement: progress and challenges to scale up high throughput field phenotyping from research to industry, in : Valasek, J., Thomasson, J.A. (Eds.), p.986604.

Contacts

Katia BEAUCHÊNE, coordinator of the High Throughput Phenotyping Tools facilities  
ARVALIS-Institut du végétal, 45 voie Romaine, Ouzouer Le Marché, F 41240 BEAUCE LA ROMAINE
Antoine FOURNIER, Sensor specialist
ARVALIS-Institut du végétal (based at Photonics-Bretagne - 4 rue Louis de Broglie, 22300 Lannion, France)


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