| Populus davidiana Dode is a wildely distributed native tree species in China, is one of the most important mountain broadleaf trees. The material quality is quite well, the wood-color is white, its wood is homogeneous, light and soft, which is the high-quality industrial material. This study used the provenance and family conservation of Populus davidiana Dode in Qingshan Forest Farm, Linkou County, Heilongjiang Province, as the test material. The phenotype and DNA levels were researched to analyze the poplar genetic diversity. At the same time each plant genetic distance based on 208 SSR markers, with the plant material product of the characters, the core collection is eatablished and evaluated, and we establish a core vitro conservation of it, and were used to conduct a preliminary study. Designed to poplar genetic resource evaluation, protection and preservation of, genetic improvement strategies that will provide^ the scientific theoretical basis, and good use of poplar genetic resources to provide technical support. The studies come to the following key findings:1. The phenotypic variation of P. davidiana Dode is very rich in provenances and provenances in many traits, there were significant genetic variation, especially in height, diameter and volume growth traits, among provenances difference was very significant. Phneotpyic diversity index was0.664 among 0.018, among Population 0.646, Shannon infmoration index was1.469 maong Provence 0.096, among Population 1.373. Comprehensive phenotypic diversity index based clustering results may be six kinds of sources Populus divided into two categories, Fangzheng, Weihe clustered together, Hushang, Jiangshanjiao and Tieli, Shuguang force together as a classs.2.6 pairs of SSR primers were used to analyze the genetic relationship of 6 provenances of-P. davidiana, there were 29 locis amplified in the expected size fragment of the product, the percent of polymaorphic loci was 100%. Estimation of the genetic variation of 6 provenances of P. davidiana according to the Shannon index and Nei's index, the Shannon index were 1.1001 in P. davidiana, the Shannon index of FZ provenance was the highest, the number was 1.1111, the TL provenance was the lowest and the the number was 0.7508. The order or 6 provenances according to the Shannon index was:FZ>HS>WH>SG>JSJ>TL. The Nei's index of P. davidiana was 0.5957, every Nei's index was distributed from 0.4421 to 0.5944. The order according to the Shannon index and Nei's index was basically the same.3. The genetic diversity within provenance was 88.57% and the genetic diversity between provenances was 11.43%. This was indicated that the variation within provenance account for a large proportion of the sourse. The coefficient of genetic differentiation was 0.1143 which showed that the higher genetic differentiation occurred between provenances. The mean of gene flow was 1.9366, it was showed that there have gene flow between provenances, it can reduce local variation and prevent adaptive differentiation.4. Constructed the dendrogram of genetic relationship between the 6 provenances using SSR molecular markers. The genetic distance between HS provenance and JSJ provenance was close, the two provenances were clustered into one group, and SG provenance and WH provenance were clustered into one group. FZ provenance was far from other 5 provenances.5. Make use of the UPGMA clustering method, the 208 Populus make up a germplasm to and cluster random sampling method to gradually step by step cluster sampling method and packet priority clustering method, respectively,30%,25%,20%,15%,10% collected under the rate of a subset of 15 candidates, after the candidate subset of parameters of genetic diversity of a comparative study of the initial screening phase cluster sampling of priority under 20% of the core collection sampling rate of 42 Populus T3 core germplasm resources the best core collection, evaluation by the core collection of molecular diversity of 39 genotypes, alleles Na * 4.6667, effective allele Ne* 2.7288, Shannon index I* 1.1173, Nei's index H* 0.6067. Core collection phenotypic diversity assessment, the mean percentage difference was 15.42% MD%, very poor compliance rate CR79.09%, coefficient of variation was 90.00% rate of change of VR., To the core library building standards, so that the core library T30000000000000000000 Populus species should be preserved forest resources and families of 208 individuals of molecular genetic diversity of the germplasm resources preservation.6. Establish a tissue culture systerm. The optimal sterilizing method of buds was dipping into 70% to 75% alchohol for ten to twenty seconds, and then treating with 0.1% HgCl2 for about 3min; the optimal material for propogation by multiplication is of axillary buds; The optimum culture medium of differentiation was NT+6-BA1.0mg/L+KT0.3mg/L+2%sucrose, the differentiation rate was 86%, a single explant can differentiated 4.32 buds at best. The optimum proliferation culture medium was WM+6-BA1.0mg/L+NAA0.01mg/L+2%sucrose. High temperature, airtight plastic membrane and weak light can promote the vitrification, of all, the airtight plastic membrane is the most important factors. WM+IBA1.5mg/L+IAA0.01mg/L +2% surose was the optimum culture medium of rooting. The rooting rate was up to 93.2%, a single seeding has 14 roots at the most. Study on the influence of factors to rooting emphatically, There were prominent difference in the seedling age to influence on rooting rate and rooting numbers, the rooting ability which in the 30dto 35d seedling age is the most strongly.7.Populus well use for the core colledtion to factory breeding of genetic resources be used directly. Clear aspen seedlings factory production processes, simplified technology of tissue culture Populus will softwood cutting method into the tissue culture, so that the initial differentiation of the original-with the proliferation of cultured following-rooting-Nutrition Cup in four reduced to the initial phase of differentiation culture-subculture-in vitro rooting of three stages, shortening the production cycle 1 to 2 months; for different transplanting transplanting container to take a different approach, and afforestation techniques of poplar container to regulate.
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