Onno Muller is deputy head of the research area ‘Shoot Dynamics’ and group leader field phenotyping at the Institute of Bio- and Geosciences 2 : Plant Sciences at Forschungszentrum Jülich. His expertise is on the plant response to the environment focusing on photosynthesis. In different positions in Japan and the USA he worked in natural ecosystems with seasonal changes in temperature and light and combined with experimental warming at a forest scale or in growth chambers on various crops. In Germany he implemented and is coordinating field phenotyping under elevated CO2 in the BreedFACE, as well under photovoltaics in the APV 2.0. project among others where he combines ground-based positions systems as well as UAVs. In the Cassava source-sink project the UAV approach was adapted to Cassava growing in breeders plot in Nigeria and experimental cassava field trials in Taiwan where it is currently being combined with photosynthesis measurement. Plant ecophysiology /Active chlorophyll fluorescence measurements / controlled field experiments