Construction Of DArT System In Brassica Rapa

Diversity Arrays Technology is a new type of molecular marker technology based on the hybridization to microarray. The restriction loci which are different in various genotypes, result in polymorphic markers generated. The advantages of DArT technology are high throughput, low cost, high quality in scoring. DArT is especially suited for the genomes without any sequence information. Brassica rapa is one of the most important vegetables in China. The development of DArT for B. rapa is very important for genetic analysis for agronomic traits and quality traits and breeding program.We used four B.rapa accession(sZ16,L58,L143,L144)and 16 individuals from a BILs population and 32 accessions of B.napus to develop DArT arrays for Brassicea. We firstly optimized genomic complexity reduction method. Two complexity reduction methods were used to creat DArT libraries. The developed DArT array was used to screen a B.rapa BILs population. The results we got were listed as follows:1. The combinations of Pst I with BstN Ior Ban II are the most efficient methods for genome complexity reduction.2. Using combinations of Pst I with BstN I or Ban II, we created libraries for B.rapa by four representative accessions, Z16 (Chinese cabbage), L58 ( Caixin), L143 (Yellow sarson), L144 (Rapid cycling) and 16 lines from the BILs population developed from L58×L144. Each library consists of 1536 clones. In the same way, we created libraries using 32 accessions of B.napus.3. Samples of thirty-five BILs lines were hybridized to DArT array to measure the polymorphim of the arrays developed in the present study. Polymorphic clones are 235 for library of Pst I + BstN I and 187 for that of Pst I + Ban II, respectively. The corresponding polymorphic levels are 15.3% and 12.2%.4. We used DArT array to screen the BILs. Combining with the previous SSRs and SRAPs genetic linkage map was constructed with 16 main linkage groups covering a total distance of 1277.7cM. This map includes 356 DArT markers,85 SSR markers and 102 SRAP markers. The average interval distance was 2.97cM.