RAPD MARKERS LINKED TO A CLUBROOT-RESISTANCE LOCUS IN BRASSICA-RAPA L

Linkage of random amplified polymorphic DNA (RAPD) markers with resist ance genes to clubroot (Plasmodiophora brassicae Wor.) in Brassica rap a L. was studied in a doubled haploid (DH population obtained by micro spore culture. Thirty-six DH lines were obtained from F-1 plants from a cross between susceptible 'Homei P09' and resistant 'Siloga S2' plan ts. 'Homei P09' was a DH line obtained by microspore culture of the Ch inese cabbage variety 'Homei', which is highly responsive in microspor e culture. The resistant line 'Siloga S2' was obtained by two rounds o f selfing of the fodder turnip 'Siloga'. Three RAPD markers, RA12-75A, WE22B and WE49B, were found to be linked to a clubroot-resistance loc us. These three markers were linked in the DH lines and an F-2 populat ion and should be useful for marker-assisted selection in breeding pro grams.