Variation Regularity Arnd High Growth Gene Screening Of Half-sibling Families Of Ancient Ginkgo Biloba L.

Ginkgo biloba L. is a valuable economic tree species whit high economic value. Its fruit,leaf and wood have been widely used. Besides, as an ancient relic plant in the gymnosperms,ginkgo biloba has extremely important theoretical value and great significance of ginkgo.China's ancient ginkgo tree resources, although relatively abundant, it is greatly decreasing due to the environmental change and many other factors. Therefore, the protection and utilization of ginkgo trees is particularly urgent.By far, the study of half-sibling families for local ginkgo biloba, especially the family of morphological indexes has been carried out in some part of our country. However, collecting seeds of ginkgo biloba on the nationwide and studying the half-sibling families have not been reported. In this study, we collected 130 ginkgo tree seed in 98 countiesin the nationwide ,planted seedlings, and then builded ginkgo half-sibling families germplasm resources nursery.Then the growth indexes were measured, the karyotype analysis and the AFLP molecular markers of the half-sibling families of ginkgo biloba were studied. We analyzed the variation characteristics of ginkgo half-sibling families from growth, cell level and molecular level,respectively, evaluating the excellent the half-sibling families with good growth at seedling stage. According to the morphological characteristics of ginkgo tree species, the distribution rules of ginkgo biloba seeds were analyzed to provide reference for the further evaluation of improved varieties. In addition, in this study we excavated candidate genes related to high-growth traits of half-sibling families using BSR technology by high throughput sequencing .This study will provide valuable information for the follow-up study of functional gene and molecular breeding practice. Also, it will give insights into the construction of genetic linkage map, the main effect of growth traits QTL and so on.The main results of this study are as follows:(1) According to the ginkgo half-sibling families growth for 3 consecutive years, we selected 8 excellent half-sibling Ginkgo families, such as Guangxi Xing'an (72) et al.According to the ginkgo half-sibling families genetic diversity results,we found that the genetic diversity of northern and south western regions, is higher than the central region and eastern region. In addition, 28 ginkgo half-siblings families karyotype analysis showed that the evolution of the ginkgo biloba direction from northeast to southwest and Guizhou, sichuan area. According to the analysis of the evolution trend and genetic diversity of Ginkgo biloba,we ultimately selected 2-3 excellent Ginkgo half-sibling families in western region, south region, north region and the eastern region, respectively.(2) In this study, eight pairs of AFLP primers have used to amplify 297 of ginkgo half-sibling families. In total, 1727 bands were detected, all of which were polymorphic bands.And half of the 8 pairs of primers have single band. Thus, ginkgo half-sibling families showed high levels of polymorphism. The flow value of Nm estimated by Gst was 1.4085 among ginkgo half-sibling families, which showed that there is a certain degree of genetic exchange between the free pollination families of ginkgo biloba, but the level is low.(3) According to the morphology difference of ginkgo seed, this study will be the main distribution area of the ancient ginkgo seed is divided into 5 regions: the eastern region,middle region, northern region, the southern region and Western region. Besides, there is no significant relationship between the nutrient composition and geographical area according to the analysis of seed nutrient composition. Eastern region seeds, which mainly distributed in Shandong, Jiangsu and Zhejiang provinces, are relatively large, and can focus on the selection of nuclear with ginkgo seed.(4) In this study, BSR technique was used to carry out the sequencing for two ginkgo half-sibling families (high growth and low growth) in Panxian, Guizhou Province in two mixed pools. 601 differentially expressed genes were identified, in which 513 were functional annotated. SNP analysis of two samples of high growth and low growth have been detected.Totally, 119 genes have been associated , in which 58 genes were functional annotated.