[1] MPI Plant Breeding Res, D-50829 Cologne, Germany
[2] Albrecht von Haller Inst, D-37073 Gottingen, Germany
[3] ETSIA Univ Politecn, Dept Biotecnol, Madrid 28040, Spain
[4] Inst Pflanzengenet & Kulturpflanzenforsch, D-06466 Gatersleben, Germany
[5] CNRS, Inst Sci Vegetal, F-91190 Gif Sur Yvette, France