Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2000
Publication Date: N/A
Technical Abstract: Host specific resistance genes control dwarf bunt of wheat caused by Tilletia controversa. The virulence/avirulence reaction to the resistance genes Bt-1 through Bt-10 has been described previously for the named dwarf bunt races D-1 through D-17. Recently, wheats have been identified that are monogenic for the additional resistance genes Bt-11, Bt-12, Bt-13, Bt-14, and Bt-15. These wheats have been added to the list of differential cultivars used to determine pathogenic races of dwarf bunt and common bunt fungi. This study determined the virulence reaction of the named dwarf bunt races to Bt-11 through Bt- 15. Twelve additional geographically diverse isolates were also tested against these genes. Of all the isolates tested, two were slightly virulent to Bt-11 and Bt-12 whereas all other isolates were avirulent to Bt-11 and Bt-12. Most isolates were virulent to Bt-14 and Bt-15, and about one third of the isolates were virulent to Bt-13. This information further characterizes the named dwarf bunt races and will provide a basis for future investigations of pathogenic races. The resistance of Bt-11 and Bt-12 to all isolates demonstrates these genes to be useful sources of resistance.