SCREENING THE BRASSICAS CZECH NATIONAL COLLECTION FOR SOURCES OF CLUBROOT RESISTANCE

Centre of Applied Research of Vegetables and Special Crops of the Crop Research Institute holds genetic resources collections of vegetables, aromatic, medicinal and special plants in Olomouc. Brassica vegetables collection consists of 353 accessions including landraces, old and advanced cultivars as well as breeding materials from 26 countries. Recommended amount of 12 thousand seeds are stored in gene bank in -18°C in active and/or basic collection. Passport data of accessions are available online. All these genotypes are free for breeding, teaching and research activities. Each accession is characterised, conserved and also evaluated for clubroot disease (Plasmodiophora brassicae). A total of 126 accessions of cabbage (Brassica oleracea var. capitata), 50 cauliflower (Brassica oleracea var. botrytis) and 30 kohlrabi (Brassica oleracea var. gongylodes) varieties were screened for resistance to clubroot disease under controlled conditions in the plant growth chamber. Thirty-eight the most resistant genotypes of cabbage were selected for further Plasmodiophora brassicae tolerance testing for yield in the infested and non-contaminated fields. The highest resistance of cabbage under artificial conditions was found in genotypes Early Wakefield, Boehmerwaldkohl-Sumavske and Turnovske, the most resistant cultivars of cauliflower were Brilant and Agora and the most resistant genotypes of kohlrabi were represented by cultivars Adriana, Nichtschiessender and Indigo. The highest tolerance of cabbage under field conditions was found in Wiam cultivar. The tolerance of plants growing in infested field was 58.1% of the yield of plants from non-infested field. Tolerant are also cultivar Jersey Queen and breeding line OR-100. There was not found any fully tolerant genotype from the whole collection of 38 accessions. Tolerance of evaluated genotypes ranged between 8.4 and 58.1%. Screening for tolerance under field conditions is the aim of the follow up research.