| Hoya carnosa R. Br, belonging to Asclepiadaceae family and Hoya genus, derives from southeast Asia and Australia. It has been studied that Hoya has excellent adaptability to different environment and has high ornamental value and medicinal value. However, at present, there are fewer studies on the genetic background of Hoya germplasm resources and tissue culture technology, which restrictes the variety breeding and large-scale factory production of Hoya. Therfore, in the study, ISSR molecular marker technology was combined with softwares like NTSYS to analyze the genetic polymorphism of these many Hoya germplasm resources introduced from local areas of Fuzhou and Southeast Asia, and at the same time, the Hoya tissue culture technology was studied. These studies were aimed at providing the scientific basis and technical support for further development and application of Hoya germplasm resources, the medicinal composition analysis and large scale production. The results are as follows:1 Analysis of genetic polymorphism of HoyaISSR molecular marker technology was used to carry out ISSR-PCR analysis on the 43 Hoya germplasm resources. We got 12 ISSR primers, whose electrophoretic bands are clear and polymorphic is good, selected from 42 ISSR random primers. From the obtained Hoya fingerprint map, we totally got 69 bands between 200 bp to 2500 bp with the 12 primers. The bands were all polymorphic, and the percentage of polymorphism reached 100%, which indicated there was high genetic polymorphism in Hoya germplasm resources.2 the analysis of genetic similarity coefficient of Hoya germplasm resourcesNTSYS2.10e was used to analyze the genetic similarity coefficient of 43 Hoya samples. The results showed that the genetic similarity coefficients between individuals among Hoya germplasm resources are between 0.464 and 0.797, which further proved the rich genetic diversity among Hoya germplasm resources. Among those, the genetic similarity coefficient between Hoya carnosa and Hoya acicularis was lowest (0.464), which meant the greatest genetic distance between them. However, the genetic similarity coefficient between Hoya bella in and Hoya bella out was highest (0.797), which meant the nearest genetic relationship between them.3 The genetic cluster analysis of Hoya germplasm resources based on the genetic distanceBased on the genetic distance, NTSYS2.10e was used to cluster the 43 Hoya germplasm resources. According to the clustering tree, the Hoya germplasm resources could be divided into two big groups with a threshold of 0.527. Hoya carnosa, from the local Fuzhou, and the morphologically different Hoya acicularis, were classified in the A group, the left were classified in the B group. When the threshold was set to be 0.545, the two different Hoya in the A group further separated. When the threshold was set to be 0.574, the B group was divided into B-a and B-b two subgroups. among those, Hoya compacta var in and Hoya compacta var were classified in a subgroup, and the others were classified in the other subgroup. Genetic clustering analysis results were consistent with the geographically distribution or morphological differences of different Hoya germplasm4 The induction and proliferation of Hoya callusThe heart-shape leaves of Hoya were used as experiment material to study the effect of different media on the induction, proliferation, and differentiation of Hoya callus. The results showed that, the medium (MS+6-BA2.0 mg/L+NAA 0.5 mg/L+ 2,4-D 1.0 mg/L+GA 1.Omg/L) with 3% sucrose was optimal in the study for the induction of callus, with the induction rate of 70.8%; the induced Hoya callus got highest proliferation efficiency (8.80) on the medium (MS+6-BA2.0mg/L+ NAA0.5mg/L+2,4-D1.0mg/L+GA1.5mg/L+sucrose 3%), and the callus were of bright colour and growing well; in the study on differentiation of Hoya callus, highest differentiation efficiency rate (0.37) and best effect were got from the medium (MS+NAA 0.5 mg/L+GA 1.0 mg/L+KT 1.0 mg/L+sucrose 3%). |
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