Genomic composition of microspore-derived plants from a Chinese cabbage (Brassica rapa ssp pekinensis) x heading cabbage (B-oleracea var. capitata) allotriploid (ACC) hybrid based on genomic in situ hybridisation

摘要

Genomic in situ hybridisation (GISH) was used to investigate the chromosome composition of five microspore-derived plants previously obtained from a Chinese cabbage (Brassica rapa ssp. pekinesis) x heading cabbage (B. oleracea var. capitata) allotriploid hybrid (ACC). Chromosome numbers and compositions varied between the microspore-derived plants examined. Plant 'GB-17' contained 17 chromosomes, of which ten and seven were derived from B. oleracea (genome C) and B. rapa (genome A), respectively. Plant 'GB-18' contained 18 chromosomes, including nine C and nine A chromosomes. Plant 'GB-19' was an allodiploid plant that contained 19 chromosomes, including nine C and ten A chromosomes. Plant 'GB-20' contained 20 chromosomes, including eight C and 12 A chromosomes. Plant 'GB-26' contained 26 chromosomes, including 12 C and 14 A chromosomes. Recombinant chromosomes were observed in plants 'GB-17' and 'GB-20'. The morphological features and meiotic behaviour of plant 'GB-19' were further examined and compared with the two parental plants. Chromosomal homoeology between the A and C genomes was revealed. Our results provide credible evidence to identify the different chromosomes between the two genomes. In addition, GISH was shown to be a powerful tool with which to characterise the genomic composition of hybrids and to reveal chromosome recombination events during hybridisation.