RAPD markers linked to locus controlling resistance for race 4 of the black rot causative agent, Xanthomonas campestris pv. Campestris (Pamm.) Dow. in Brassica rapa L.

摘要

Association between th RAPD markers and the resistance to race 4 of the black rot causative agent was studied in Brassica rapa L. Experiments were carried out using doubled haploid lines, obtained via crosses between the race 4-susceptible fodder turnip and resistant pak-choi, and the F_2 progeny of the crosses between the doubled haploid lines with contrasting resistance. The WE22_980 RAPD marker inherited from the pak-choi and associated with the clubroot susceptibility was also linked to the locus responsible for the resistance to race 4 of Xanthomonas campestris pv. Campestris. The two other RAPD markers were linked to susceptibility to black rot. Simultaneous association of the same DNA marker with the resistance/susceptibility to two different obligate pathogens favored the hypothesis on cluster organization of the resistance genes in plants. The markers described can be sued in plant breeding and in further investigation of the genetic bases of reassistance in plants.