| Crueifelae Brassica species are important vegetable and oil crops in the world. There are many Crueifelae Brassica cultivars and wild species in China. The rapeseed yield in China accounted for about thirty percent of world. The major cultivated crop is Brassica napus (2n=38, AACC). As transgenic technology developing and commercial applying, the varieties of transgenic rapeseed crops and its cultivated area increased. Some countries have large-scale cultivation of transgenic rapeseed crops and maybe import to China. Their safety issues currently receive more and more attention. The occurrence and frequency of intraspecific gene flow can vary according to having enough-scale cultivation of transgenic rapeseed crops, relative species density, the outcrossing rate, synchrony of flowering, and geographical proximity. Using data on rapeseed wild relatives from herbarium, flowering season and cultivated area in China a formula for the Risk Index (RI) is set up in this study. The highly risky area by the calculated result is Sichuan province, followed by Jiangsu province, Guizhou province, Zhejiang province and Shanghai, etc. It is suggested to avoid transgenic rapeseed cultivation in these locations to reduce gene flow according to the evaluation result of RI index. Xinjiang has the most wild relative species, but cultivated area This research utilizes distribution data of cultivated rapeseed and wild relatives to analysis the risk of transgenic gene-flow in China, andproposes the preventive methods.We hope to collect more data on rapeseed wild relatives to do more comprehensive evaluation.Using data on rapeseed wild relatives from herbarium, a large number of wild Brassica species are retain in Xinjiang.The crop wild relative has been used for cultivar development and breeding in order to improve crop production and quality. Argument remained for the species identification of wild Brassica in Xinjiang. Seed coat morphology is known to be an excellent character for taxonomic and evolutionary studies, thus understanding its structure and inheritance has been a useful support for species identification and utilization. The material was12accessions (XJ-14～14and XJ-Baicheng) provided by the Xinjiang (XJ) Agricultural Academy, and13accessions (ZS-2～16) collected in2011by the authors from Zhaosu (ZS), Xinjiang, China. This study aims to identify wild Brassica species collected from Xinjiang in China, through hybridization compatibility, seed coat microsculpturing (SCM), flow cytometry, and specific DNA markers. The results showed that wild accession ZS-11, ZS-13and XJ-Baicheng were hybridized relatively well with B.juncea, tetraploid and contained both A and B genomes specific loci, and that their SCM was reticulate pattern and similar to that of B. juncea. The other wild accessions were hybridized relatively well with Sinapis arvensis, diploid and carried S-genome specific DNA makers, and the seed coat of which was rugose pattern and similar to S. arvensis. It was worth mentioning that XJ-Baicheng maybe crop because of100%germination, large seed size, and yellow seed coat by maternal effect. Therefore, XJ-Baicheng could be an escaped cultivar of B. juncea species. Additionally, the characteristic of SCM was found to be inheritable in the interspecies hybrid progenies formed between Brassica species. It was implicated that the characteristic of seed coat pattern is related to genomic type and maternal effect. The result could provide theoretical support for the taxonomy of the wild Brassica species and is helpful in understanding the relationship between seed coat phenotypes and genetic characteristics.The sustainable utilization of the crop wild relatives in China needs to do more research. |
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