The inheritance of clubroot resistance in Brassica napus L

Abstract

The inheritance of resistance of Brassic napus L. to races Band C of Plasmodiophora brassicae Wor. was investigated in glass-house cxperiments. In crosses between white-fleshed N.Z. Clubroot Resistant rape and yellow-fleshed N.z. Wilhelmsburger swede, resistance to race Band race C was determined by single dominant, non-allelic genes. There was no linkage between flesh colour and clubroot resistance. N.Z. Wye swede was in general resistant to races Band C. Resistance to race B in crosses between Wye swede and Club root Resistant or Giant rape was controlled by one do-minant gene. Resistance to race C in crosses between Wye and Wilhelmsburger swedes was controlled by one dominant gene which was non-allelic with the one present in Clubroot Resistant rape. The F1 of Wye swede and Giant rape was predominantly susceptible to race C. F1 crosses between different plants of Wye swede and Sensation swede varied from full susceptibility to predominant resistance. It is suggested that resistance in Wye swede was controlled by a combinat;on of dominant and recessive genes or that race B and race C were mixtures of bictypes with differing pathogenicity to Wye swede. © Taylor & Francis Group, LLC.