네덜란드 와게닝건대학 식물육종연구실에서는 배추과 채소들을 형태적 지리적 근원을 찾아 대표 형태형을 나타 내는 수집단을 분류하는 Core Collection 연구가 이루어지고 있다. 배추과 채소들은 대부분 Heterogeneous 하고, Heterozygous 하기 때문에 본 실험실에서는 와게닝건 대학으부터 배추과 채소 중 8개의 형태형을 나타내는 19계통 (Chinese Cabbage 3계통, Chinese Turnip Cabbage 2계통, Pak Choi 3계통, Turnip 5계통, Broccolleto 3계통, Mizuna 1계 통, Komatsuna 1계통, Turnip green 1계통)을 분양 받아서 소포자배양을 진행 하였다. 소포자배양를 진행한 결과, 8 가지 종들 중, Komatsuna 와 Turnip Green을 제외한 6종에서 모두 배의 발생을 유도 할 수 있었고, 유도된 배들은 식 물체로의 재생을 위해 MS배지에 옮겨졌고, 토양순화, 저온처리 의 과정을 거쳤다. 이들 6종들 중 Broccolleto를 제 외한 5종에서 채종이 가능하였다. 배추과 채소의 Core Collection을 위한 19계통의 소포자배양 결과, 10계통에서 배 가 유도되었으며, 발생된 배의 개체 수에는 차이가 크게 나타났으나, MS 배지로 옮겨진 배들은 10계통 모두에서 정상적인 뿌리를 형성한 Adventitious shoot가 재생되었고, 토양에 4주 이상 적응한 식물체를 획득할 수 있었다. 10 계통 중 2계통을 제외한 8계통이 4주 동안 저온처리의 과정에 적응하였고, 이들 중 7계통에서 채종과정을 거쳐 종 자생산에 성공하였다.

For genetic mapping studies, biparental segregating populations are often useful, however recombination is limited, giving rise to large genomic regions under QTL, and one can only study alelles present in both parents. In Wageninegn UR, a core collection is being developed representing all Brassica rapa morphotypes and geographic origins. As most B. rapa accessions are heterozygous and heterogeneous, we started a project to fix the collection through microspore culture. The resulting Diversity Fixed Foundation Set will be an interesting resource for association mapping studies, which have as advantage that they present the allelec variation present in the collection, and for mapping studies recombination is increased. Nineteen accessions of eight subspecies of Brassica rapa were used for microspore culture to developdoubled haploid lines. Eight morphotypes were represented: 3 Chinese cabbage, 2 Chinese turnip cabbage, 3 Pak choi, 5 Turnip, 3 Broccolleto, 1 Mizuna, 1 Komatsuna and 1 Turnip greenfrom the 19acessions examined, embryos were obtained for 13, representing six subspecies (Komatsuna and Turnip Green had no response). The embryo yields differed significantly between these 13 accessions. We regenerated normal plants from 10 accessions that survived more than 4 weeks in the soil using microspore culture. Nine accessions flowered after 4 weeks vernalization at 5℃ and seeds were harvested from 5 accessions. From a Mizuna, we obtained 3791 seeds from one plant and total 7318 seeds were harvested from 5 accessions representing 4 subspecies(Chinese cabbage, Chinese turnip cabbage, Pak choi, Mizuna). At present, we carry out experiment for obtain more seeds and induce embryos from the other plant materials.

We have identified ATTIRTA1 transposon, a kind of mariner-type DNA transposon from Brassica rapa genome. A total of 811 inverted-terminal repeat, ITR consisting of the both terminal on ATTIRTA1 transposon were found from B. rapa v1.1 sequence. Among them 616 ITR were paired by two in each transposon, indicating three quarters of the transposon exists in original form. Around 10 percentage of the transposon, 82 ITR was located in gene, expecially only in intron. Using these ATTRRTA1, we developed a display system modified from AFLP technique and applied for this system to analyze genetic diversity of Korea Brassica rapa core collection. The collection includes 220 accessions representing the different morphotypes and geographical origin. The analysis of population structure revealed five subgroups and the clustering patterns matched well with their morphological traits. ATTIRTA1 transposon display seems useful marker system for studying genetic relationships. Presently we have profiled the components and contents of glucosinolate in the core collection to analyze genome wide association. This collection will be helpful to identify agriculturally desirable traits from other supspecies.