BLACK ROT OF CRUCIFERS AND SOURCES OF RESISTANCE IN BRASSICA CROPS

Since the early 1990s, diseases caused by Xanthomonas campestris have been spreading on new host plants and in new regions, that had not bee n previously affected by the pathogen. Still, vegetable crops of Brass ica oleracea are the most damaged plants by black rot. Recent achievem ents in the studies on resistance to black rot were reviewed. For the first time resistance genes were identified based on gene-for-gene int eraction with different races of the pathogen. Some East Asian cabbage and Portuguese Penca kale cultivars seemed to carry the homologous ge nes for race-specific resistance. Their origin in Asian cabbages was t raced to the Flat Dutch group of varieties and to heading Mediterranea n kale. It is suggested that never non-specific stem resistance found in Chinese kale, broccoli and cabbage might be an alternative means of genetic protection against the pathogen.