| Brassica campestris originated in China. It is well used as an oil crop and also a vegetable. There are rich germplasm of B.campestris in China. B.campestris has several elite traits such as tolerance to poor soil and drought, resistance to coldness etc. These good traits including long pod, yellow-seeded, multi-chamber and high oil content etc. can be transfered into B.napus by interspecific hybridization to improve target traits of B.napus and enrich its genetic background.In this study, 172 germplasm selected from the previous collection were used to study the genetic diversity of B.campestris in China by RAPD technology. Based on the results of morphological identification and RAPD analysis, a part of collection with similar genetic background was removed in the further study. The left 82 varieties were employed to study the origin and evolution of B.campestris in China using MEGA software (Molecular Evolutionary Genetic Analysis) . Multi-chamber and self-compatible B.campestris were discovered during the identification of germplasm. Buds were sampled from different developmental stages to carry out the anatomic study. Homologue sequence and PCR walking were employed to clone SZ-G and eSRK. The reason of self-compatibility was analyzed based on comparison of DNA and arnino acid sequences predicted between self-compatible and self-incompatible B.campestris. The main results are as follows:1 Genetic diversity of B.campestris in China1.15. campestris were separated into 15 groups: 6 groups from northern origins, 8 groups with southern origins and one mixture group.1.2 The origins of B. campestris in China were significantl related to geographical distribution. The diversity level of spring-type is higher than that of winter-type.1.3 The genetic variation of landraces from Yunnan-Guizhou-Hubei and Qinghai-Gansu-Xinjiang provinces is more than from other provinces because the genetic diversity of them is much higher than landraces from other provinces. This might be related to origin of B.campestris.2 Origins and evolution of Brassica campestris in China2.1 Based on morphological, RAPD and RAPD-morphological combined data, three phylogenetic trees were constructed and revealed origins and evolution of B.campestris in China. The results are in correspondence with previous study. The phylogenetic relationships of B.campestris revealed by three phylogenetic trees are coincident.2.2 It was showed that B.campestris var. oleifera originated earlier than B.chinensis var. oleifera. In B.campestris var. oleifera, winter type originated earlier than spring type. B.chinensis var. oleifera might originate in the area of Yunnan, Guizhou, Sichuan and Hubei. The evolution of B.chinensis var. oleifera was later than B.campestris var. oleifera, but different landraces formed because of southern geographical diversity.3 Anatomic study on multichamber character in B. campestris3.1 Anatomic structure was studied by investigation of ovary crossing sections in different developmental stages. In multichamber ovary, there are 12-16 carpel vascular bundles which link into a circle during carpel development. Afterwards, carpel chamber begin to differentiate. Ovule and pseudo-septum generate simultaneously separating the ovary chamber into tri-chamber or tetra-chamber. Some ovarys develop into bi-chamber because of degeneration of pseudo-septum. In contrast, there are 8 carpel vascular bundles in bi-chamber ovary. Ovule and pseudo-septum generate simultaneously separating the ovary chamber into bi-chamber, developing intobi-chamber pods. 3.2 The multichamber trait was controlled by one pair of recessive genes (memo) andaffected by environmental factors. 4 Cloning of SLG and eSRK genes and comparative analysis4.1 Homologue sequence method was used to clone S-locus gene: eSRK (extracellular SRK) and SLG. The fragment size of SLG of qinhuang, yellow sarson and guanzhong were 882 bp (GenaBank ID: AY448026, AY448028, AY448030). The eSRK of qinhuang, yellow sarson and guanzhong were 915 bp, 914 bp and 94...
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