Researches On Conservation Of Germplasm Resources Of Superior Chinese Date (Ziziphus Jujuba Mill.) And Its Propagation Techniques And Introduction Of Ziziphus Mauritiana Lam.

1. Chinese jujube(Ziziphus jujuba Mill.) is one of the special fruit crops originated in China. In order to effectively conserve and make use of the existing elite Chinese jujube resources, it has been studied that how to collect and conserve them based on the climatic demarcation result of the central jujube distributing area. In addition, the propagation techniques of elite Chinese jujube cultivars are studied in the present dissertation. According to the data of 13 geographic and climatic factors collected from the 40 sampling places in main distributing area of Chinese date, the area is divided into 4 climate zones, 3 sub-climate zones by the methods of principal component analysis (PCA) and clustering. Based on the climatic demarcation result, more than 70 superior cultivars of Chinese date (Ziziphus jujuba Mill.) are primarily selected and 65 of them are used to establish the germplasm plantation of superior jujube cultivars according to DNA fingerprint identification. These elite cultivars come from 13 provinces, cities or autonomous regions, i.e. Beijing City, Heibei Province, Shandong Province, Shanxi Province and so on, and respectively belong to different climatic regions. The collected elite cultivars involve each climatic distributing area of Chinese date by and large. A 2hm2 germplasm plantation of superior jujube cultivars was established in Huangfa seedling nursery, Daxing County, which located in the south suburb of Beijing City. The layout of the plantation conforms to completely randomized block design, repeats 4 times and 5 trees in each plot. The plantation is worth being conserved and used permanently, because new elite cultivars can be selected in it, in addition, ordinary and advanced breeding plan can be carried on and lots of superior seedlings can be propagated in the plantation. Compared with other germplasm and experimental gardens, the germplasm plantation is the largest, most integrated and most normative one in China, which would surely play an important role in researches on the jujube resources conservation and jujube breeding. These cultivars are greatly different in tree characters, phenological phase , fruit shape, fruit quality and resistance. Therefore they have broad genetic background, and can adapt to a variety of environmental conditions.2. It has been studied that the appropriate factors in tissue culture to rapidly propagate some elite jujube cultivars including Tongbaidazao, Zanhuangdazao and Pingguozao. The optimal initiation, multiplication and rooting mediums for rapidly propagate Tongbaidazao are MS + BAl.Omg/L+IBAO.Ol-O.lmg/L, MS + BA1.5mg/L + IBA0.5mg/L + GA0.5 mg/L, 1/2MS + BAO.Olmg/L + IBA2.0mg/L + IAA0.5mg/L respectively. The fast propagation approach for Tongbaidazao is presented. In addition, the fairly suitable multiplication and rooting mediums for propagating Zanhuangdazao and Pingguozao have been selected.Using Chinese Jujube (Ziziphus jujuba Mill. cv. Jinsixiaozao) as cutting test material, the physiological mechanism of stem planting has been probed. By comparing the rejuvenated and adult softwood cuttings of Chinese jujube, which were treated by NAA, it can be found that the premodium differentiation of roots appeared on the rejuvenated cuttings and the increasing callous, but no roots, on the adult cuttings within 15 days. On ninth day, the quantity of endogenous auxin (IAA) reaches the peak in rejuvenated cuttings. However, the quantity of endogenous auxin (IAA) is steadily low in the adult cuttings. The quantity of endogenous bascisic acid (ABA) in the rejuvenated cuttings is remarkably different from that in the adult cuttings on the ninth and twelfth day after stem planting. Furthermore, the activities of peroxidase and indoleacetic acid oxidase in rejuvenated cuttings are relatively lower than in the adult cuttings. Also, the bands of peroxidase isozyme of the two kinds of cuttings are different after stem planting.3. In this paper, the classification status of Z.mauritiana in the genus Ziziphus, its adaptivity, the selection of climatic zone suitable to introduce Z.mauritiana, and its propagation techniques are studied. The main results are as follows:The method of cladistics was used to analyze phylogenetic relationship of 13 species of the genus Ziziphus distribute in China. Based on the morphological comparison, 27 characters with 66 states were chosen to be computed using the computer program Hennig86 (1.5) and a most parsimonious tree (L=152,CI=60,RI=71) were obtained. The 13 species of genus Ziziphus were divided into 4 groups by the tree of phylogenetic relationship. Z. mairei Dode. is the most primitive group and Z.mauritiana and Z.oenoplia (L.) Mill, constitute a monophyletic group. These results could be the theoretical basis of Z.mauritiana breeding and cultivation, moreover, these could offer a framework to study the phylogenetic relationship of the genus Ziziphus in the future.The diurnal Tr variation of all the tested Z.mauritiana materials showed single-peak; along with the decrease of soil water content, the Pn of Z.mauritiana rootstocks fromdifferent provenances decreased simultaneously; the wild type of Z.mauritiana was less influenced by drought stress than other tested material; as to the capability to produce solid substance, the Z.mauritiana of Guangzhou provenance is among the highest of the tested materials under drought stress. Along with the decrease of soil water content(SWC), the water using efficiency (WUE) of the tested materials decreased, however, the WUE slightly increased when the SWC was less than 8%^—10%. The tested materials have drought-avoiding mechanism in different degree. The wild type of Z.mauritiana has the highest drought resistant capacity according to the index of WUE. In Beijing, the Z.mauritiana could grow and bear fruit perfectly if it is cultivated in conservatory, and the quality of the fruit should be assayed.Using the methods of gray clustering and gray connecting analysis, the climatic factors, i.e. temperature, humidity, rainfall of the provenance of Ziziphus mauritiana and the regions that plan to introduce the genus Ziziphus mauritiana in, are fully analyzed and compared in this paper. According to the results, the map of climatic zone suitable to introduce Z.mauritiana is worked out. As to the limited factors of the different regions, the problems, which should be paid attention to, are put forward.The experiment to grow seedlings of Z.mauritiana rootstock showed that:l) the endocarp retarded water penetration of the seeds; cracking the endocarp caused the seeds to germinate 20 days earlier; 2) treated by GA3, the germination couldn't be improved significantly; 3) Treated by ABT rooting powder of different concentration, the highest rooting percentage and survival rate of Z.mauritiana cuttings reached 76%.