The Study On Assessment Of Germplasm Resources Of Radix Astragali

The material of this study is based on the original plants of Radix Astragali, recorded in China Pharmacopoeia(2005 edition),which are Astragalus membranaceus (Fisch.) Bge.vat.mongholicus(Bge.) Hsiao and A.membranaceus(Fisch.) Bge.43 portions of seeds of Radix of Astragali from different areas were collected,26 parts of which are of A.membranaceus var.mongholicus,and the other 17 are of A.membranaceus,and 28 portions of medicinal root were collected from original production places,19 are of A.membranaceus var.mongholicus,9 are of A.membranaceus.To conduct germplasm comparing,Astragalus seeds were cultivated in two places of Beijing and Shanxi.16 morphological and agronomyic traits,such as growth highness,stem diameter,root leingth,dry root weight,etc,were observed and measured.The content of astragalosideⅣof medicinal roots from original production places and one-year cultivated plants was analyzed.And the genetic diversity and genetic relationship of cultivated and wild germplasms were analyzed by the method of RAPD molecular marker.Based all data obtained from each analysis,the conclusions were reached to as follows.1.From the traits of seed of A.membranaceus var.mongholicus or A.membranaceus,it was showed that,significant variance in 1000-seed weight and germination ratio resided in different varieties and different population germplasms.The seed of A.membranaceus var.mongholicus has the higher 1000-seed weight and germination ratio than that of A.membranaceus.It was also found that the population germplasms from Inner Mongolia have the lowest 1000-seed weight and highest germination ratio among the three A.membranaceus var.mongholicus production places of Shanxi,Gansu and Inner Mongolia.2.Based on the analysis of the morphological and agronomic traits of one-yeair-old Astragalus membranaceus var.mongholicus,which were cultivated in experiment field in Beijing and Shanxi,it is showed that there is significant variance in the traits,such as growth highness,stem diameter,stem branchness number,fresh root weight,dry root weight,root length,root diameter,resided among different population germplasms.But the leaf traits are stable.The traits of root have higher variance than the traits of aerial part.The variance among different population germplasms is also higher than that of different individuls within one population germplasm.3.The traits having relationship with dry root weight,the trait representing the production of Astragalus herb,and the traits having the relationship with root length and root diameter,the traits representing the apperance quality of Astragalus herb,were analyzed.It was showed that growth highness,stem brachness number,fresh root weight,root diameter have significant positive correlation with dry root weight.The compound leaf number has correlation with root length.And growth highess,stem diameter,stem branchness number,length breadth ratio of leaflet,fresh root weight,dry root weitht,branch root number have correlation with root diameter.4.Based on the principal component analysis,5 principal compenent in the expenriment field of Beijing were obtained,its total cumulative contribution is 82.561 %,the results knowed that the main variance is from the traits of root diameter,fresh root weight,dry root weight,growth highness,stem branchness number,dry root diameter,stem diameter,branch root number.and 3 principal compenent in the expenriment field of Shanxi province were obtained also,its total cumulative contribution is 84.024%.the result showed the the main variance is from growth highness,stem diameter,length of leaflet,stem branchness number,fresh root weight, root diameter,dry root weight,branch root number,diameter of 30cm length of root.5.A cluster analysis was used to generate dendrogram based on Euclidean genetic distances among 16 morphological and agronommic traits.It is showed that all the population germplasms were clustered together with 5 class at 12.5 level in the expenriment field of Beijing,and 5 class at 12.5 level in the expenfiment field of Shanxi province.The dendrogram is not well concorded with geographic distribution.6.The genetic diversity and genetic relationship were assessed based on 29 populations and 141 individule samples of A.membranaceus var.mongolicus and A.membranaceus by the method of RAPD molecular markers.At varieties and population level,the percentage of polymorphic bands of A.membranaceus var.mongholicus were 92.56%and 48.52%respectively,and those of A.membranaceus 85.95%and 31.34%respectively.It is showed that the variance is higher among different population germplasm than that within germplasm based on Nei's gene diversity(h) and Shannon's information index(Ⅰ) at variety and population level.The germplasm of A5 and B1 have the higher heterozygosity,and can be used in breeding. The germplasms having near distribution area have more chance of gene communication.There are also some exceptions,some germplasms,distributed far from each other,have close genetic distance,which may be explained that they were introduced from same areas long time ago or occurred by cross-pollination when propagated in near field.7.The contents of astragalosideⅣin one-year-old roots of Astragalus herb cultivated in experiment field,the roots collected from original production places,and the wild roots were determined by HPLC method.It is showed that the contents of astragalosideⅣare variance in all the population germplasms.Referring to 2005 Chinese Pharmacopeia,only 27%of the samples cultivated in Beijing reached the standard of astragalosideⅣ(＞0.040%),and 44%of the samples cultivated in Shanxi province reached the standard.It is demonstrated that the growth in second year is important for astragalosideⅣaccumulation.The samples from same population germplasm but cultivated in Beijing or in Shanxi,have different content.It may be explained by environment influence.Both the roots from original production places, most of which is collected after two-year growth and from wild collection,there contents of astragalosideⅣreached the standard.And the contents of astragalosideⅣof wild roots is higher than that from original production places,growing in same place. This phenomenon may be attributed to the environment and special gene influence.The germplasms from Inner Mongolia have stable and consistent contens of astragalosideⅣ.8.The results of germination ratio,morphological and agronomic traits,genetic diversity and genetic relationship and the contents of astragalosideⅣwere combined, some good germplasms of Astragalus herb can be selected,their numbers are A1,AS, A7,A12,Bland B19.