Analysis On Genetic Diversity Of Tartary Buckwheat Accessions From Tibet, Shaanxi, Yunnan, Guizhou And Sichuan

Tartary buckwheat, belonging to the Fagopyrum Gaerth genus of Polygonaceae family, is one of the two cultivated species. It can be served as edibles and medicaments and the special nutritional elements could meet the demand of nutritional balance. Meanwhile, along with the extensive research on its pharmaceutical value and health-care effect, tartary buckwheat has become the focus of attention. In addition, tartary buckwheat is significantly different from the major cultured crop (mainly belonging to Gramineae), hence the study and utilization of buckwheat will play an important role to alleviate the dilemma of the uniformity of cultured crops and cultivars and promote the diversity and balanced development of crops.The study of tartary buckwheat was conducted at late stage and little progress was made. There are still a series of problems in its production. Therefore, the work on screening and study of specific and specially-purposed original resources of tartary buckwheat will be beneficial to apply them into breeding and production and meet the demand of different kinds of products of buckwheat.In this thesis, PCR with intron-splice junction primers and long random primers, combined with morphologic method were employed to reveal the genetic diversity among 108 tartary buckwheat accessions from Tibet, Shannxi, Yunnan, Guizhou and Sichuan. The factor analysis was used to analyze the agronomic traits, and then the result was used for systematic cluster analysis. A [1, 0] data matrix was established based on the PCR data and the genetic similarity coefficients was determined and then used for the cluster analysis and constructing the evolutionary tree. The main results are as followed:1. The results of morphologic analysis showed that there were significant differences among 108 materials investigated. The variation coefficients of 8 qualitative traits were 36.73%for diameter of main stem, 28.5%for branches in the main stem, 21.77%for the width of leaves, 20.8%for plant height, 20.34%for the length of leaves,18.35%for nodes in the main stem, 12.37%for 1000 kernels weight and 10.89%for growth days. There were also variations in the 11 characterization traits, such as 9 kinds of seed colors were observed. The cluster results showed that all the accessions could be divided into four categories and 12 subclasses. The differences in the qualitative traits were obvious among these classifications, but that was not so significant in accessions from different regions since the investigated materials from the same province could be divided into different categories, indicating that the tartary buckwheat resources were diverse in the five provinces.2. The results of the molecular marker analysis showed that the genetic similarity coefficient ranged in 0.57-0.95 with an average of 0.77, indicating that there was some genetic diversity among investigated materials, but in general, the diversity was limited. It was suggested that we should expand the areas in which materials were collected to utilize more ecological kinds of resources. The cluster results showed that all the accessions could be divided into 13 categories and the former 9 categories including 86 accessions were the major clusters, the genetic similarity coefficient between every two accessions was great in each cluster, but that were smaller between every two accessions in each of the 10-13categories. The regional caharacteristic was observed in each of the former 9 categories, indicating that the origin of tartary buckwheat accessions and the difference in the agronomic traits could be well presented in the former 9 categories.3. It was advisable to pay more attention to the material named 1081 from Liuba in Hanzhong of Shannxi, which distinguished itself from the category. These materials also deserved more attention including 1100 from Ningshan in Hanzhong of Shannxi, XZK042 from Leiwuqi in Changdu of Tibet, XZK008 from Cayu in Nyingchi of Tibet, and SCK021 from Jinyang in Liangshan of Sichuan, which set themselves from other materials in individual categories.