xBrassicoraphanus, a new synthetic intergeneric hybrid between Brassica rapa L. ssp. pekinensis and Raphanus sativus L., also locally known as ‘Baemoochae’, is an interesting subject for studying polyploidy and genome plasticity in the family Brassicaceae, but very few genomic and cytogenetic information. Here, we analysed the chromosome complements and pairing of the most fertile lines, BB1 and BB5, using dual-color fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) to check their chromosomal segregation stability. The somatic chromosome complement of B. rapa was confirmed to be 2n=20 (2.8~4.8μm), of R.sativus, 2n=18 (2.0~3.3μm), and of xBrassicoraphanus, 2n=38 (2.2~5.0μm). There were eight, eight, and seventeen metacentric pairs and two, one, and two submetacentric pairs in B. rapa, R. sativus, and xBrassicoraphanus, respectively. Additionally, three, two, and five pairs of 5S rDNA and five, three, and eight pairs of 45S rDNA were observed in B. rapa, R. sativus, and xBrassicoraphanus, respectively. This suggests that both B. rapa (AA) and R. sativus (RR) genomes, particularly the rDNA arrays, co-exist in xBrassicoraphanus (AARR) genome. In meiosis I, nineteen bivalents were most frequent, and GISH analysis showed ten bivalents from the A genome. This study would provide a useful information for further genomic study of xBrassicoraphanus and its improvement as a new promising breeding variety.

본 연구에서는 양파와 파간 종간교잡 F1의 불임성의 한 요인으로 여겨지는 염색체 이상과 교잡식물체의 염색체의 조성을 밝혀 향후 종간교잡을 이용한 양파의 형질개량과정에 종간교잡 육종의 효율성을 높이고자 하였다. 종간교잡식물체의 감수분열 염색체를 관찰한 결과 중기에 7쌍의 2가염색체와 2개의 1가염색체가 관찰되었다. 체세포 염색체수는 16개로 양파, 파의 염색체 수와 같았으며 GISH한 결과 파와 양파의 염색체가 각각 8개씩 확인되었다. 5S, 45S, T