Plasmodiophora brassicae Wor. is the one of the causative agent of disease of the family of Brassicaceae, that results in decrease of white head cabbage yield up to 10-60%. The aim of the work was the study of genetic variability of doubled haploid lines of white head cabbage obtained by the isolated microspore culture in vitro aimed at selection of the lines resistant to P. Brassicae and development of resistant hybrids. The doubled haploid lines of white head cabbage were evaluated for resistance to Plasmodiophora brassicae using the method of inoculation of seedlings by pathogen in the control condition of the chamber room. As a result of assessment, the high disease distribution among doubled haploid lines was found (25- 100%), but disease development was not higher than 68%. The score of infestation was 0.5-3.3, that was comparable with the standard (3.5). The plants of the lines 3-3-3 did not exhibit any symptoms of disease that can indicate of efficiency of its gene resistance or pathogen heterogeneity. The lines with high resistance to P. brassicae were used as a parental lines for development of F1 hybrids. Using the top-crossing method the forty-two hybrid combinations were developed based on self-incompatibility. These hybrid combinations were analyzed for clubroot resistance in the field conditions on an artificial infectious background in Moscow region. Based on the data of two-year experiments, all tested hybrid combinations were divided into the groups of relatively tolerant (52.4%) and susceptible (45.2%) genotypes. Only one hybrid combination developed with line 3-3-3 has proved to be tolerant. The score of infestation of hybrid combinations varied from 0 to 1.8. The score of infestation of the standard was 2.5. The disease distribution reached 80% but disease development varied from 0 to 25%.

Clubroot disease (Plasmodiophora brassicae Wor.) is among the most economically important and harmful diseases of the cole crops. In the Federal Scientific Vegetable Center annual monitoring the biological agent dissemination, buts also a phytoimmunological evaluationof collection and selection specimens and also directional material are carried out in order to find new resistance sources. For this purpose an artificial infection background is used: compost obtained from decomposed nodules on the cabbage roots affected with clubroot disease (infection load 10sup5sup-10/sup6/sup spores/cm3) was applied. The resistance of white cabbage varieties was evaluated during the harvesting period using a 5-point scale of the root system damage, which formed the basis for categorization into resistance groups. For the analysis of artificial background intensity and specimen ranking plants of the white cabbage variety Slava 1305 (a susceptibility standard) were randomly planted throughout the infectious area. The influence of weather conditions of the research year on the results of phytopathological evaluation of the breeding cabbage samples with infection was shown. Under unfavorable conditions for pathogen development (2014) most specimens (74%) were categorized as relatively resistant, while in pathogen favourable year - 2015 such samples comprised only 5% of the total number of studied specimens. Since the same specimen may show a different level of resistance depending on the year conditions, the stability of character manifestation is the important criterion for identification of the resistance sources. Phytopathological evaluation aimed at selection of clubroot-resistant forms in the Moscow region should last at least three years even with the use of infection background. Long-lasting evaluation showed that the strains No 234/15, 140/14, 216/17 exhibiting high resistance to clubroot against artificial infection background regardless of the year conditions are the most valuable for selection. | Одним из наиболее экономически значимых и опасных заболеваний капустных культур является кила, (возбудитель – Plasmodiophora brassicae Wor.). В Федеральном научном центра овощеводства проводят не только ежегодный мониторинг распространения возбудителя, но и непрерывную фитоиммунологическую оценку коллекционных и селекционных образцов, а также линейного материала с целью поиска новых источников устойчивости. Для этого используют искусственный инфекционный фон: вносят компост из разложившихся желваков корней капусты, пораженных килой (инфекционная нагрузка – 10sup5sup-10/sup6/sup спор/см3). Оценку на устойчивость сортообразцов капусты белокочанной проводили в период уборки по 5-ти балльной шкале поражения корневой системы, на основании которой образцы дифференцировали по группам устойчивости. Для анализа напряженности искусственного фона и ранжирования образцов рендомизированно по всей площади инфекционного высаживали растения сорта Слава 1305 – стандарта восприимчивости. Показано влияние погодных условий года исследования на результаты фитопатологической оценки селекционных образцов капусты на инфекционном фоне. При неблагоприятных условиях для развития патогена (2014 г.) большая часть образцов (74%) вошла в группу относительно устойчивых, тогда как в благоприятном 2015 г. таких образцов было всего 5% от общего числа изученных. Поскольку один и тот же образец может проявлять разную степень устойчивости в зависимости от условий года, то при выделении источников устойчивости важным критерием является стабильность проявления признака. Фитопатологическую оценку с целью отбора устойчивых форм к киле в Московской области необходимо проводить не менее трех лет, даже с использованием инфекционного фона. По результатам многолетней оценки, наиболее селекционно ценными являются линии №№ 234/15, 140/14, 216/17, у которых независимо от условий года проявлялась высокая устойчивость к киле на искусственном инфекционном фоне.