Preliminary Study On The Genetic Diversity And Seedling Traits Variation Of Castanopsis Sclerophylla

Castanopsis sclerophylla is a kind of evergreen tree which belongs to Fagaceae family, and it's an important ecological and potential economic species in subtropical area .So it's necessary for us to carry out researching in genetic resources, economic traits and genetic variation. This study would provide guideline for genetic and plantation improvement. Moreover, it will supply the lack of natural subtropical domain trees study.After field investigation and collection of seeds and blade in natural distribution of C. sclerophylla,geographic variation of seed characters of C. sclerophylla in different areas was analyzed. By SSR markers with the experimental materials, the study found out genetic variation and population genetic structure of C. sclerophylla.At the same time, we further researched genetic structure of the typical C. sclerophylla population and variation of seedling characters of C. sclerophylla. The main results were as follows:(1)The study on the structure and spatial were carried out in six Castanopsis sclerophylla sampling plots of Tianmu Mountain.The result shows that all the populations of C. sclerophylla were spindle type. The age of structure of populations were declining due to lacking seedling and sapling. The overall population distribution followed a random type. Population dynamics analysis showed the spatial distribution pattern changed from aggregate type to random type during the course of population growth. One reason is that Scores of seeds from populations were fallen pray to rodents, the other reason is that the patterns not only were closely related to the ecological and biological characteristics of each species and relationships of competitive exclusion among them, but also to the environment. The character of population reproductive mode is that the contribution rate of asexual reproduction is far greater than sexual reproduction. Maintenance and natural regeneration of C. sclerophylla populations adopted mostly sprout regeneration. To a certain extent, it affects the direction of succession. C. sclerophylla populations should restore the ecological balance through transforming environmental factors.(2)Research of genetic diversity using SSR markersThe study of population genetic diversity should be essential to conserve it effectively. Population genetic diversity of ten natural C. sclerophylla populations was studied with 6 microsatellite loci. The result showed that a middle level genetic diversity was detected in the C. sclerophylla. Populations.Average number of alleles were 4.8.The mean expected heterozygosis was 0.53,The major of genetic variation occurred within populations, which could be concluded from the coefficient of genetic differentiation(FST=0.1299) was low. The level of gene flow(Nm=1.6746) was high.(3)Genetic structure of different origin ways of Castanopsis sclerophylla populationsGenetic diversity of the population with different origin way was studied using SSR molecular marker. The results showed the gentic levels of diversity was seed tree> seedling. and C. sclerophylla of 19 possible genetic offspring distribution pattern analysis showed that 84.2% seedlings delivered from selfing within population results. The main reason was that the mother plants have more ramets and get more genes form mother plants. Then, it reduced to accept foreign pollen effectively and caused gene flow. It was easy causing genetic drift and inbreeding genetic differentiation. It's impossible for population to cause genetic structure of recession.(4)Variation of Castanopsis sclerophylla seed charactersThe Castanopsis sclerophylla seed length, seed diameter, seed length×seed diameter, seed length / seed diameter and hundred grain weight from nine areas were studied. Results showed that extremely significant difference was found in C. sclerophylla seed characters of different areas. Most coefficient of variation is hundred grain weight and much less is seed length / seed diameter. Correlation analysis showed that seed length and seed diameter were the significant positive correlation with hundred grain weight ; seed would became bigger and heavier according to dropping latitude, Annual average temperature and frost free period become longer;hundred grain weight is significant positive correlation with rainfall, seed length/seed diameter is significant negative correlation with rainfall.(5)Research results of genetic variations of seedling characters in different areasThe growth processes of C. sclerophylla at seedling could be divided into tow periods: fast-growing period(5-9months) and induration period. There were significant differences in seedling height and diameter (DFH, diameter at floor height). There were significant differences in seedling height and diameter (DFH, diameter at floor height). And seedling traits were mainly controlled by heredity. Correlation analysis showed the growth of seedling height was also remarkably correlated to latitude, and base diameter wasn't correlated to longitude. In addition to Seed length/ seed width, other seed traits were nothing with seedling characters by correlation analysis. Variance analysis for seedling height and diameter was that the difference was significant,and Shangrao was most significant in nine provenances. So Shangrao was best in nine nine provenances.