1. Department of Horticultural Sciences, Centro de Investigaciones Científicas y Tecnológicas de Extremadura, Ctra. A-V, Km 372, 06187 Guadajira, Badajoz, Spain.
2. Department of Agricultural Chemistry and Soil Science, University of Córdoba, Campus Rabanales, Edificio Marie Curie — Ctra, Nacional IV-Km 396, 14071 Córdoba, Spain.
3. IPB Escola Superior Agrária de Beja, 7800-295 Beja, Portugal.