1. Department of Botany; Faculty of Science; Palacký University in Olomouc; Šlechtitelů 27 783 71 Olomouc Czech Republic
2. Sunflower and Plant Biology Research Unit; USDA-ARS; Fargo ND 58102 USA
3. Department of Plant Pathology; North Dakota State University; Fargo ND 58102 USA