High-throughput field phenotyping: bridging scales from gene to canopy for trait discovery

Recent improvements in phenomics have opened up vast opportunities to understand and predict dynamic phenotypic responses to genotypic variation. To date however, a great majority of phenomics studies are conducted in controlled condition facilities, such as growth chambers and greenhouses, in which plants function as individuals. In crop species however, plants function as canopies. This drastically changes the way they function and limits the relevance of some controlled condition studies. Thankfully, field phenomics platforms are emerging. We will present the results of a prototype developed to study the response of wheat genotypes to nitrogen in France. This system, based on RGB cameras and reflectance spectroradiometers, characterized the dynamic canopy response of over 200 wheat genotypes throughout the growing season. Analysis of the phenotypic dataset generated shows that traits relative to canopy structure and function are linked to the overall yield response of wheat to nitrogen. Preliminary genome wide association and functional mapping of these traits is underway and shows promise in identifying how genetic variation modifies canopy traits. These traits should contribute to linking results at lower scales to economically important crop variables such as yield. The accessibility of the phenotyping methods presented is increasing, thanks to the development of higher-throughput and more automated systems.