1. Department of Agricultural Sciences; University of Naples Federico II; Via Università 100 80055 Portici Italy
2. CNR-IBBR Institute of Biosciences and Bioresources; Via Universita' 133 80055 Portici Italy
3. Centro de Biotecnología y Genómica de Plantas; INIA-UPM; Campus de Montegancedo 28223 Madrid Spain