[QTL for seed germination rate and related physiological traits of Brassica napus L].

One hundred and eighty-three recombinant inbred lines from the cross between GH06 and P174 were used for genetic analysis of seed germination rate and physiological trait analysis of Brassica napus L. Composite interval mapping (CIM) was applied to identify QTL associated with seed germination rate (GR) of the seeds that stored for two years (STY), one year (SOY), and fresh seeds (FS), respectively. The activity of lipases, seed conductivity, reducing sugar content, total sugar content, and root vitality of STY and FS were investigated. The QTL for seed GR of various stored seeds were different. Three QTLs for STY were detected on the linkage group (LG) 9, 14, and 17. Two QTL for SOY were mined on LG 5 and 9. Two QTLs for FS were detected on LG 4 and 18. The germination rate of seeds from three years was significantly different, and the QTL of GR was not identical, which indicated that the seed germination was controlled by many loci. Furthermore, the seed germination rate was negatively correlated with seed conductivity, which means that measurement of seed conductivity can be used to estimate GR, and the study of conductivity is important for GR research.

Localization of QTLs for seed color using recombinant inbred lines of Brassica napus in different environments.

Yellow seed is one of the most important traits of Brassica napus L. Efficient selection of the yellow-seed trait is one of the most important objectives in oilseed rape breeding. Two recombinant inbred line (RIL) populations (RIL-1 and RIL-2) were analyzed for 2 years at 2 locations. Four hundred and twenty SSR, RAPD, and SRAP marker loci covering 1744 cM were mapped in 26 linkage groups of RIL-1, while 265 loci covering 1135 cM were mapped in 20 linkage groups of RIL-2. A total of 19 QTLs were detected in the 2 populations. A major QTL was detected adjacent to the same marker (EM11ME20/200) in both maps in both years. This major QTL could explain 53.71%, 39.34%, 42.42%, 30.18%, 24.86%, and 15.08% of phenotypic variation in 6 combinations (location x year x population). BLASTn analysis of the sequences of the markers flanking the major QTL revealed that the homologous region corresponding to this major QTL was anchored between genes At5g44440 and At5g49640 of Arabidopsis thaliana chromosome 5 (At C5). Based on comparative genomic analysis, the bifunctional gene TT10 is nearest to the homologue of EM11ME20/200 on At C5 and can be considered an important candidate gene for the major QTL identified here. Besides providing an effective strategy for marker-assisted selection of the yellow-seed trait in B. napus, our results also provide important clues for cloning of the candidate gene corresponding to this major QTL.

[SRAP study on genetic diversity of radix plygoni multiflori in chongqing].

OBJECTIVE: To detect the polymorphisms of Radix Plygoni Multiflori in chongqing by means of a new marker system SRAP. METHOD: Different shaples of Radix Plygoni Multiflori from major production areas were collected. The SRAP was used to asses divergence among 16 populations. The data were analyzed using unweighted pairgroup method, based on arithmetic averages (UPGMA) bootstrap analysis. Cluster analyses was performed by using DPSv3.01 software, the alkaloid was extracted from P. ternate with chlorolform. RESULT: 104 combinations generated 250 polymorphie bands, the cluster analysis indicated that 16 materials could be distinguished into two main groups and one special type, Nei&Li similarity coefficient ranged from 0.23-0.99, and the average distance is 0. 44. CONCLUSION: The results of the study showed a potential application of SRAP fingerprinting for identification of Radix Plygoni Multiflori.