Clubroot-resistance in Bmssicomphanus (an= 36 ; ccrr genome), which originated from the progeny of Bms.sica oleracea var. capitata cv. Miikechuseix Raphunus sativu.s var. longipinnatus (the cultivar is unknown), was tested using Williams’ races 2 and 4 in comparison with some cruciferous crops with an insertion-inoculation method. Three strains of Brassicoraphunus were not infected with the two physiological races suggesting this intergeneric plant has a stable and strong resistant gene to clubroot disease. Neither hybrids between Bmssicoraphunus and high to moderate resistant cultivars of Japanese radish or cabbage nor hybrids between Brassicoraphanzls and susceptible cultivars of Chinese cabbage or turnip were infected with the two races. It is concluded from these results that clubroot resistance in Bmssicoraphunus is controlled by a dominant gene, and that Bmssicoraphunus is useful for breeding clubroot resistant cruciferous plants.