Abstract：To explore an effective and reliable karyptyping method in Brassica crop plants, genomic DNA was isolated from Brassica oleracea genome, labeled as probe with DIG-High Prime Mix kit; genomic DNA was isolated from Brassica rapa genome as block reagent. In situ hybridization to mitotic spreads, specific fluorescent signals were showed on each pair of homologous chromosome. Nine pairs of Brassica oleracea genome were exactly identified. It provided a feasible and accurate method to discriminate species with small chromosomes. And it set up an important found to research localization of self-incompatible genes.
