1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 90183 Umea, Sweden
2. Centre de Ressources Régionales en Biologie Moléculaire, Université de Picardie Jules Verne, 80039 Amiens, France
3. Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 78371 Olomouc, Czech Republic
4. Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 90187 Umea, Sweden
5. Department of Agronomy and Horticulture, University of Nebraska, Lincoln, Nebraska 68583-0915
6. University of Agricultural Sciences and Veterinary Medicine, 400372 Cluj Napoca, Romania
7. Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318 Institut National de la Recherche Agronomique–AgroParisTech, Institut National de la Recherche Agronomique Centre de Versailles–Grignon, F-78026 Versailles cedex, France