Univ. Grenoble Alpes, CNRS, Grenoble INP, TIMC-IMAG, 38000 Grenoble, France.|UR 1115 PSH, INRA, F-84914 Avignon Cedex 9, France.|UR 1115 PSH, INRA, F-84914 Avignon Cedex 9, France.|Virtual Plants, INRIA, Montpellier, France.