Testing of Inoculation Methods and Susceptibility Testing of Perspective Cabbage Breeding Lines (Brassica Oleracea convar. Capitata) to the Black Rot Disease Caused by Xanthomonas Campestris pv. Campestris

The susceptibility of twenty-four cabbage breeding lines to Xanthomonas campestris pv. campestris was evaluated. The selection of appropriate inoculation method was done on 4 cabbage cultivars ('Cerox', 'Sintex', 'Sonja' and 'Avak'). One month old plants were infected by 5 inoculation methods (spraying, injection by syringe, multiple pricking, carborundum abrasion and scissor clipping method). Four different bacterial isolates of Xcc (WHRI 3811, 3971A, 1279A; SU) and their mixture were evaluated for the aggressiveness on 'Cerox' and 'Sonja' cultivars. On the basis of obtained results, breeding lines of head cabbage were inoculated by mixture of all tested isolates using multiple pricking method. The disease severity of inoculated seedlings proved high susceptibility of young plants to the Xcc infection. The disease incidence determined 75 and 105 days after sowing showed changes for 16 of tested lines and indicated that resistance testing should be observed until mature stage. The study revealed five breeding lines (DP25, T1, IT10, Kalibos and Avak1) with disease incidence lower than 20 % as perspective sources of resistance for further breeding.