Molecular mapping of black rot resistance locusXca1boon chromosome 3 in Indian cauliflower (Brassica oleraceavar.botrytisL.)

Abstract

Black rot is the most devastating disease of cauliflower worldwide causing severe damage to crop. The identification of markers linked to loci that control resistance can facilitate selection of plants for breeding programmes. In the present investigation, F2 population derived from a cross between ‘Pusa Himjyoti’, a susceptible genotype, and ‘BR-161’, a resistant genotype, was phenotyped by artificial inoculation using Xcc race 1. Segregation analysis of F2 progeny indicated that a single dominant locus governed resistance to Xcc race 1 in ‘BR-161’. Bulk segregant analysis in resistant and susceptible bulks of F2 progeny revealed seven differentiating polymorphic markers (three RAPD, two ISSR and two SSR) of 102 markers screened. Subsequently, these markers were used to genotype the entire F2 population, and a genetic linkage map covering 74.7 cM distance was developed. The major locus Xca1bo was mapped in 1.6-cM interval flanked by the markers RAPD 04833 and ISSR 11635. The Xca1bo locus was located on chromosome 3. The linked markers will be useful for marker-assisted resistance breeding in cauliflower.