First Author:   Frédéric Rychen GREQAM - IDEP, University of the Mediterranean frederic.rychen@univmed.fr   GREQAM - IDEP, Centre de la Vieille Charité, 2, rue de la Charité Marseille Cedex 02, 13236, France   +33 6 03 95 00 15(Phone) +33 6 03 95 00 15(Fax) Second Author: Charles Figuières INRA - LAMETA figuiere@supagro.inra.fr   UMR LAMETA, 2 Place Viala Montpellier Cedex 01, 34060, France   +33 4 99 61 22 09(Phone)