| In order to study genetic diversity of C.meiocarpa and introgressive hybridization between C.oleifera Abel. and C.meiocarpa, C.meiocarpa populations of full distribute area and sympatric populations of C.meiocarpa and C.oleifera were chosen as material .In this study, research of phenotypic traits were carried out, oil content and fatty acid were analysed and evaluated, genetic diversity were measured by SRAP markers, introgressive hybridization between C.oleifera and C.meiocarpa was studied, the results are as follows:1. Phenotypic variation types of C.meiocarpa were very rich and level of genetic diversity was quite high. The phenotypic traits coefficient of variation ,relative range and diversity index were more than 0.2,0.48 and 2.7 respectively. The Phenotypic diversity index of 18 population was more than 2.5. 23 phenotypic traits existed extremely significant differences among and within 18 populations, also among most population in multiple comparison of Dumcan. The repeatability of seed and food was respectively high and stability is higher than leaf and flower. There existed significant correlations among some phenotypic traits, therefore, we could select important and key traits as primarily measured parameters. There were certain correlation and different influence among phenotypic traits and ecological and geographical factor. In binary tend Surface Analysis, the morphological traits of flower fitted best with longitude and latitude, among them, styles long ,corolla canopy width,petal count and diversity index of petal count were up to significant level, and some phenotypic traits of seed and fruit or leaf had significant correlation with longitude and latitude. The UPGMA cluster analysis of 18 populations of C.meiocarpa was implemented by mean value of 23 phenotypic traits, and cluster of C.meiocarpa reflected quietly obvious features of geographic region and were same as seed and fruit, which show that phenotypic traits of seed and fruit were most important and stablest among phenotypic traits. Most populations remained the same results between plot of the principal components analysis and cluster, and the relationship of different populations all could be discriminated by two ways. 2. Oil content and fatty acid of C.meiocarpa were very rich and level of genetic diversity was quite high also, but there were significant variation level among these traits. There existed obvious difference in coefficient of variation among 12 traits, and Palmitoleic was highest(0.341),however, unsaturated fatty acid was lowest(0.013). There were extremely significant differences among and within 15 populations on 12 traits of Oil content and fatty acid. The majority traits of 5 populations in southwest region did not exist significant differences and showed obvious similarity, but other population had significant differences in multiple comparison of Dumcan. the differentiation coefficient of 12 traits reached 27.1323% and oil content was the highest(52.5493%),apart from oil content where variation of among populations was slightly higher than that in populations, variation of fatty acid mainly existed in populations and far higher than that among populations. There existed certain correlation and different influence among 12 traits or their diversity index and ecological and geographical factor. In binary tend Surface Analysis, only saturated fatty acid and diversity index of palmitoleic exited obvious correction with longitude and latitude. The 12 traits factors were integrated into 4 principal components in the analysis of principal components. The quality level of 15 populations were evaluated by total scores which derive from the multiply value between principal components and contribution of corresponding principal components, and the results showed that the Zhang-pu and Min-qing population ranked top two respectively and Hu-bei population ranked last.3. The analysis of SRAP markers showed genetic diversity of C.meiocarpa reached quite high level and existed certainly difference among different populations. According to polymorphic percentage,Nei's gene diversity and Shannon's Information index, the genetic level of Gui-zhou population was highest, Ru-yong population lowest, and others ranked among them. The genetic diverity degree of C.meiocarpa was quite high in populations and species, genetic variation mainly existed within populations and but not among populations. There existed frequent gene flow (Nm =3.2235) and quite low degree of gene differentiation (Gst=0.1343)among populations. UPGMA clustering and principal components ranking demonstrated that apart from 3 Jiang Xi and 6 Fu-jian populations , others did not cluster according to geographic region. Mantel's test indicted there existed significant correction between genetic distance and geographical distance or altitude , which showed genetic drift play an important part in population differentiation of C.meiocarpa Hu., but Geographical reproductive isolation affect little.4. The research was carried out on Introgressive hybridization between Sympatric C.oleifera and C.meiocarpa ,the results are as follows: The degree of genetic diversity was up to quite high level and differed little between these two species. The degree of introgressive hybridization between Sympatric two species was quite high, which reduced the difference from these two species. The genetic relationship among C.meiocarpa and C.oleifera were very near. GST of 5 Sympatric populations among species was up to 0.0571, which was lower than mean level (GST =0.102)of wood angiosperm within and among population of species. The gene flow reached 10.0720, which showed the degree of reproductive isolation was very low and there existed obvious quite high level of introgressive hybridization between these two species. Through AMOVA analysis according to classification unit of species , we could found that most of variation (89.16%) existed within species, only little variation(0.84%) among species, so the degree of genetic differentiation was very low. The UPGMA clustering of 5 sympatric populations of two species showed sympatric populations of two species were clustered together first, which indicted there existed very near genetic relationship between these sympatric two species ,and even exceed relationship of allopatric C.meiocarpa. Apart from the factor that these two species possibly owned very high Concestor polymorphism, there existed highly near genetic relationship between these sympatric two species very likely owing to active gene flow and quite high degree of introgressive hybridization. The synthesis results showed C.meiocarpa very likely was a variety of C.oleifera. for their low reproductive isolation and highly near genetic relationship. GST of Min-qing (GST =0.0242)sympatric complex populations was obviously lower than that of others, gene flow(Nm=20.1271)was higher than that of others, the genetic distance(GD=0.0225) between these two species was nearest than that of others; GST of Qing Liu (GST =0.0242)sympatric complex populations was quite low also, and gene flow of that was up to 9.6210. The test samples of C.meiocarpa were Fu Jian farm cultivars which very likely derived from spontaneously long-term introgressive hybridization. |
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