Intraspecific Variability Resistance Evaluation of Brassica oleracea to Clubroot

3,791 plants of 8 cultivars of Savoy cabbage (Brassica oleracea L. var. sabauda L.), 1,304 plants of 14 cultivars of curly kale (Brassica oleracea L. var. sabellica L.) and 420 plants of 5 cultivars of Brussels sprout (Brassica oleracea L. var. gemmifera DC.), in total 5,515 plants of 27 cultivars of Brassica oleracea from plant genetic resources of cruciferous vegetables collection maintained by Crop Research Institute in Olomouc were tested for resistance to Plasmodiophora brassicae Wor., casual agent of clubroot disease under controlled conditions and compared intraspecific resistance of these crops. The most tolerant crop according to disease index was curly kale, the most susceptible was Savoy cabbage. The highest percentage of resistant plants with no visible swelling or very light swelling was found at curly kale, on the other hand the lowest was found at Brussels sprout. Disease Index varied from 52.84 to 84.26, percentage of plants in grade 0 a 1 varied from 9.29 to 41.87.