SOURCES OF RESISTANCE TO BACTERIAL-BLIGHT OF STOCK (MATTHIOLA-INCANA RBR)

Accessions of M. tricuspidata (L.) R. Br., M. aspera Boiss. and Matthi ola longipetala (Vent.) DC. were tested for their reaction to bacteria l blight of stock (M. incana R. Br.), caused by Xanthomonas campestris pv. incanae. Potted plants were sprayed with bacterial cell suspensio n, adjusted to 10(8) cells/ml. The tested accessions of the three spec ies were found highly resistant, while control plants of M. incana wer e severely infected. Interspecific F-1 hybrid plants between M. incana and M. tricuspidata also exhibited high resistance to the disease. Th e implications and the expected difficulties in breeding stock for bac terial blight resistance are discussed.