Optic for Precision Agriculture – OptiPAG

Despite all efforts made to reduce greenhouse gas emissions, global warming is on its process and is already leading to a lot of deep changes. Changes in temperature and precipitation, sea level elevation and increasing frequency of extreme weather events will considerably reduce global food production during this century. To ensure food security while conserving natural resources, Agriculture must choose the right pathways for maintaining agricultural production, despite rarefaction of water resources.

One of the ways is the creation and selection of new varieties being more tolerant to abiotic and biotic stresses, with yields compatible with the demand. If genotyping capabilities have exploded in recent years, the identification of the mechanisms (resistance, tolerance , adaptation) is very complex and requires a detailed understanding of physiological processes in the plant development cycle in its environment. This is the main issue of phenotyping.

The challenge of phenotyping today is to identify a broader set of agronomic and physiological variables of interest. Optics, and in particular optical systems based on the Ultra-Violet – visible and near infrared spectroscopy (UV-VIS-NIR) have an undeniable potential to analyze vegetation non-destructively. But if some gene expression traits are now accessible, there are others, which are essential, which can’t be directly measured. Among these, the measurement of certain traits related to the plant response to drought.

In this project, the partners decided to gather their strengths in order to implement the latest advances in terms of instrumental optics for monitoring vegetation to better understand the response to changing growing conditions, especially facing drought.

These measures will be carried out at the scale of the leaf, on preselected sunflowers genotypes (from sensitive to tolerant). From the light/matter interaction point of view, leaves are particularly complex: in terms of biochemical composition, their structure and also the fact that they host the photosynthetic metabolism. This raises two main questions. (I) How to implement the interaction light / leaf to ensure an optimal characterization? and (ii) How the parameters measured by the optical methods can they be related to the physiological state of the plant?

Providing answers to the first question by innovative optical measurements, will lead to a set of new physio-morphological traits of interest. Answering the second question should first allow to link these variables to the physiological responses of the plant and secondly to assess the sensitivity of these measures to varying water stress conditions.

The ultimate aim is to identify the optical methods that present significant potential for the measurement of traits of interest for plant selection. A prototype will be developed and tested on crops in real field conditions to assess its relevance. This interdisciplinary project will bring the state of the art to a level well beyond the current investigations, in terms of sensor development, signal processing and scientific knowledge on the interaction light / sheet.