Screening of Cabbage (Brassica oleracea L.) Germplasm for Resistance to Black Rot

Black rot of Brassica crops is the most devastating disease which causes substantial yield reduction of cabbage throughout the world. The use of resistant cabbage cultivars could be inexpensive and effective measure to combat this destructive disease. We screened cabbage inbred lines for black rot disease resistance through bioassay and identified some novel lines that showed race-specific resistance to Xanthomonas campestris pv. campestris (Xcc) races. The pathogenicity test revealed that out of 27 cabbage lines, one (SCNU-C-4074), six (SCNU-C-3631, SCNU-C-3637, SCNU-C-3639, SCNU-C-4072, SCNU-C-4073 and SCNU-C-3273), two (SCNU-C-3273 and SCNU-C-4118), two (SCNU-C-3270 and SCNU-C-4118), two (SCNU-C-3470 and SCNU-C-41148) and four (SCNU-C-107, SCNU-C-3270, SCNU-C-3470 and SCNU-C-4059) were shown to be resistant to Xcc races 1, 2, 3, 5, 6 and 7, respectively while none of these showed resistance against race 4. Furthermore, these resistant and susceptible lines were evaluated by previously reported molecular markers for black rot resistance. The molecular screening results were also revealed the existence of race-specific resistance in these cabbage lines. This result will help Brassica breeder to develop race-specific black rot resistant cabbage cultivars.