Analysis Of Genetic Diversity And Evaluation Of Ornamental Value Of Camellia Chekiangoleosa

Camellia chekiangoleosa Hu is an endemic tree species distributed in the mountainous areas in Zhejiang, Jiangxi, Fujian, Anhui provinces in China. It has high values in ornamentals, edible oil use and Chinese medicine etc. This tree may be used as the important parent in hybridization for breeding ornamnetal camellias and edible oil varieteies. It flowering in winter and spring with splend large flowers, has become known in the world of ornamental plant treasures. It has the huge potential value in woody edible oils and flower production.It was found out that the distributions, areas and resource quantities of C. chekiangoleosa are reducing rapidly, close to be in imminent danger through field surveys of germplasm resources and literature comparative analysis. Therefore it is urgent and necessary to do a systematic research on its current status quo and the genetic diversity so as to propose conservative strategies to protect it.This study primarily discovered its distribution status, ecological environment, endangered situation, threatening factors, genetic diversity, genetic relationship of the four similar species, and evaluation of ornamental value etc by means of doing field work, community composition investigation, phenotypic character analysis, molecular markers, chloroplasts gene sequencing. The main findings are as follows:1. The study showed that wild C. chekiangoleosa is mainly distributed in Wuyi and Huaiyu Mountains, and horizontally distributed at north latitude 25°50'~31°, east longitude 113°52'~121°2', and vertically distributed between 360~1600m above sea level.The resources of plantation and semi-wild forest is in samll quantity, which only remains 2266.67hm2, mainly in the area of Lishui regional, such as Jinyun County, Qingyuan County, Songyang County, Jingning County and Qingtian County in Zhejiang province, covering 2153.33hm2 in total. So the cultivation resources mainly distribute in the southwest of mountains and central hilly basin in Zhejiang province. It also revealed that Camellia chekiangoleosa has 200-year history in Xiapu County of Fujian province. Semi-wild forest mainly distributes in Dexing region of Jiangxi province.2. The results of community component of C. chekiangoleosa indicated that there were 86 families of vascular plants, including 202 genera and 363 species in C. chekiangoleosa communities from 5 provenances. The dominent families were Rosaceae, Fagaceae, Theaceae and so on. Floristic characteristics displayed complicated ingredients in communities, and in the geographical elements of genera, tropical composition proportion was slightly lower than temperate components in proportion. The vegetation had the character of transitional from temperate to tropical. It also showed that floras of the five provenances all belonged to East-China province in Sino-Japanese. Evergreen trees dominated in communities of the five provenances. In the vertical structure the layers were obvious and there were five plant layers, among which large trees in upper tree layer were few and tree canopy in middle tree layer was not continous, the individual number in shrub layer and in middle and lower tree layer were comparatively dominant. The important value of species showed that C. chekiangoleosa was dominant in plantation and not in wild forest. The community living envirnment of each provenance was nearly similar because the high-bud plants of each provenance were all majority. The statistics of species diversity revealed that Shannon-Wiener index and Pielou index in shrub layers were significantly larger than the index in tree layers. The indexes of species diversity in lower tree layers were larger than the indexes in the other tree layers. Above all, the species diversity was all higher among the five communities.3. The analysis of phenotypic diversity of C. chekiangolesa showed the variations within populations or between populations were rich. The differences of 22 phenotypic traits of leaf, flower, fruits and seeds in 10 populations measured in this study were found to be very significant, and the coefficients of variations were comparatively larger. The depth of the splited style got the highest value of variation, the variation coefficient was 55.11%, the second was 30.95% of the petal width and flower diameter, and the lowest was 3.91% of leaf blade thickness. According to principle component analysis,the first three main components made the contribution of 66.36% to variation. Although it didn't reach over 80%, it still contained most information of phenotypic traits. The average phenotypic Differentiation coefficient (12.62%) of the 22 phenotypic traits indicated that phenotypic variations within populations (87.38%) were larger than the ones between populations (12.62%), and phenotypic variations within populations were the main variation source. High level of diversity was detected, with an average Shannon index (I) of 1.7187. The clustering results of phenotypic markers showed that: ten populations had been divided into three clusters. The clusters and geographical origin had obvious correlation. The more close in geography of the populations the more similar in phenotypes, such as Kaihua, Tiantai and Jinyun in Zhejiang province, and the three populations, such as Yuexi, Yongxing, Xiapu were independent at 15 threshold, showing that the three populations distinguish from the others.4. Genetic diversity of 210 individuals from seven populations of Camellia chekiangoleosa from its whole distribution were analyzed using ISSR molecular markers. A total of 384 loci, of which 372 were polymorphic ones, were detected using 21 ISSR primers. The results revealed an extraordinarily high level of genetic diversity at species level. Total percentage of polymorphic loci (P, % ) was 96.88% while Shannon's information index (I) and Nei's gene diversity (h) were 0.4966 and 0.3331 in the species. Whereas the genetic diversity at population level of Camellia chekiangoleosa was relatively low, and the value of P%, I and h were 59.79%, 0.3106 and 0.2077, respectively. The genetic differentiation (Gst= 0.3758) among the populations showed that the level of genetic differentiation among populations was lower than that within populations, Analysis of molecular variance (AMOVA) demonstrated that among-region variation accounted for 12.0%, the among-population component accounted for 28.0% of the total variations, while the within-population component accounted for 60.0%. The genetic differentiation was relatively high and the gene flow was low (0.8304). The pair-wise mean genetic distance among populations was 0.1696. The cluster analysis of 210 individuals showed that Kaihua population and Tiantai population were in one group, then with Jinyun, and then Xiapu, Yuexi and Nanfeng, and Yongxin population separated from all the other populations in the dendrogram. There is a certaqin association between geographical distance and genetic consistence. Thus it may be inferred that C. chekiangoleosa of Anhui Yuexi and Fujian Xiapu county might be introduced from Zhejiang Province.5. The analysis of chloroplasts gene psbA-trnH sequences showed that the four related species, such as C. chekiangoleosa, C. lucidissima, C. liberisamina, C. crassissima have the same genetic sequence of psbA-trnH, sharing the similar result of ITS sequencing analysis. This findings indicated that the genetic relationship of the four similar species is extremely close to each other. C. crassissima, however, is significantly different from the other three Camellias and its genetic relationship is relatively far from the other three ones. Thus it can be preliminarily determined that C. chekiangoleosa, C. lucidissima, C. liberisamina belong to the same species, and the genetic relationship between C. crassissima and the others needs to be studied further.6. By using AHP and questionnaire for experts methods, the level structural evaluation model and index system of ornamental character were proposed. The 16 greater weight indicators were selected, such as growth potential, plant shape, color of flowers, florescence, fruit color, bloom season, growth habit, young shoots color, flower visibility, the amount of flowers per unit area, flower fragrance, the number of flowers , fruit shape, leaf densities, colored petals types, fruit diameter etc.