[1] Univ Littoral Cote Opale ULCO, Dept Econ & Management, MRSH, 21 Quai Citadelle,BP 55528, F-59383 Dunkerque 1, France
[2] Univ Montpellier, INNOVATION, CIRAD, INRAE,Montpellier SupAgro, TA C85-15,73 Rue Jean Francois Breton, F-34398 Montpellier 5, France
[3] CIRAD, UMR INNOVATION, Yaounde, Cameroon
[4] CSIR STEPRI, Sci & Technol Policy Res Inst, POB CT 519, Accra, Ghana
[5] IITA Cameroon, POB 2008,1st Main Rd IRAD, Yaounde, Cameroon