1. Applied Biochemistry Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D‐06466 Gatersleben, Germany
2. Department of Plant Nutrition, Estación Experimental de Aula Dei (CSIC), Av. Montañana 1005, Campus de Aula Dei, E‐50059 Zaragoza, Spain