Radix Scutellariae Issr Genetic Diversity Analysis And The Method Of Building The Core Germplasm Research

Scutellaria baicalensis Georgi is one old and well-known drug in tradition Chinese medicines and widely used for treatments of bronchitis, hepatitis, tumors, and inflammatory diseases. Recently, the flavonoids of S.baicalensis have been reported possessing the effects on the cardiovascular function obstacle, antioxidant, antitumor, cancer and inhibit the human immunodeficiency virus (HIV-1). During the process of wild-growing to domestic-cultivation for S.baicalensis, although the yield greatly increased and met the needs of the market, the collection resources of wild S.baicalensis has been over-dug and destroyed seriously with the increasing scarcity of wild resources. In production, medicinal herb growers or companies only cultivate without breeding for a long time, which makes the collection of cultivated S.baicalensis degrade very seriously. The heterogeneity and instability of medicinal quality and yield quality brought a lot of hidden dangers to the clinical and the market price fluctuations.In this study,107S.baicalensis samples of collection resource taken from main producing areas in six regions of two provinces were adopted as the research objects to preliminarily study the genetic diversity of collection resource with using ISSR molecular markers as the main research methods. Results revealed the phylogenetic relationships among the different collection and populationand provided the basis for further evaluation and preservation of S.baicalensis collection resources and breeding of new varieties. On the basis of molecular markers, different approaches were exploited to initially construct the core collection of S.baicalensis, and laid a foundation for improving efficient preservation and rational utilization. The main findings are as follows:1. Combining internet data with resources survey, S.baicalensis is mainly distributed in Northeast China, North China and eastern Inner Mongolia grassland, and is mainly produced in Hebei, Shaanxi, Shanxi, Inner Mongolia and northeast provinces. S.baicalensis has a strong adaptability and is mainly grown in wasteland, sunny hillside and hilltop grasslands. This study collected S.baicalensis mainly in six regions from Hebei and Shaanxi, and analyzed problems involved in the production of S. baicalensis and provided a scientific basis for the preservation of S.baicalensis collection resources. In this study, the damage of the wild resources and the degradation of the S.baicalensis germplasm are analyzed, we concluded that the evaluation and the breeding of the germplasm is the main method to solve the problem.2. Using a modified CTAB method to extract S.baicalensis genomic DNA. The extracted DNA has a higher quality and has been tested to be qualified for ISSR amplification reactions.18screened ISSR primers were used to analyze S.baicalensis genomic DNA for ISSR molecular marker analysis, and a total of480distinct bands were achieved, of which461bands were polymorphic, in which polymorphism percentage (Ap) is96.04%, Nei’s genetic diversity index is24.56and Shannon’s information index is0.3868, indicating that the collection resources of S.baicalensis have a high genetic diversity on the whole in the level of DNA molecules. Through UPGMA cluster analysis, S.baicalensis samples were divided into three groups in the position of the similarity coefficient of0.69. Further analysis of the clustering results revealed that all taxa showed a certain correlation with the geographical origin, and are also divided by different geographic origins in principal coordinates analysis; the results of two classification methods are basically consistent.3. The content of main active ingredient, baicalin, of S.baicalensis produced in different producing areas was significantly different. The baicalin content of S.baicalensis in Yan’an area is the highest, reaching an average of18.63%, whereas that from the traditional producing area Chengde, Hebei is the lowest, with an average of13.07%. Using Euclidean distance to measure the extent of the differences between the various collections and using maximum distance to perform cluster analysis in107Scutellaria hierarchical samples. Results showed that the main active ingredient of S. baicalensis is not related to the geographical origin.4. Try to construct a core collection of S.baicalensis based on molecular marker data grouping, using random sampling cluster strategy(RS), Stepwise clusters with random sampling strategy(SCR) and least distance stepwise sampling(LDSS) to construct core collection, and using genetic diversity parameter statistics and assess to analyze the three modeling methods. According to40%(43)、35%(37)、30%(32)、25%(27)、20%(21)、15%(16)、10%(11)、5%(5) of the sampling ratio, The genetic diversity of core collection and primary collection result showed when the sampling ratio is10%, the number of effective alleles, Nei’s genetic diversity index and Shannon’s information index were101.54%,102.87%,100.52%, respectively, which were higher than those in other sampling ratios, therefore, the proportion of10%is determined to be the optimal sampling ratio. Comprehensive comparison showed that of least distance stepwise sampling(LDSS) is the. Further analysis showed that the core collection has representative and can represent the genetic variation of the primary collection, Thus laid the theoretical basis of material basis for the protection and utilization of S.baicalensis.