Abstract: In order to study the relationship and identify different chromosomes between the A and C genome of Brassica, the labeled genomic DNAs of Chinese cabbage and cabbage were respectively hybridized to their metaphase chromosomes. Nonuniform distribution of the fluorescent labeled probe DNAs were observed on all the chromosomes of two species that were tested. The signal patterns varied between species and were related to the genome DNA probes. When Chinese cabbage genomic DNA as probe, the signals were almost only in the pericentromeric regions and the nucleolus organizer regions(NORs) of Chinese cabbage and cabbage, but the signal regions were larger in former than latter. While cabbage genomic DNA as probe, the signals dispersed along the chromosome lengths of cabbage and enhanced signal bands were shown in all pericentromeres and the NORs; Only were observed in the pericentromeres and the NORs of Chinese cabbage chromosomes, and that all the signal intensity was weaker than with genomic DNA probes of Chinese cabbage. Karyotypes of Chinese cabbage and cabbage were analyzed based on GISH signals. The results provided a molecular cytological basic for identification of interspecific hybrids, their chromosomic components and homologous between A and C genomes.

Key words: Chinese cabbage, Cabbage, Genome in situ hybridization, Interspecific hybrid, Chromosome, Karyotype analysis