Study On Genetic Diversity Of Different Provenances Of Paris Polyphylla Var.chinensis

The tubers of Paris polyphylla var.chinensis contain steroidal saponins as the main medicinal components,which have various pharmacological activities and good medicinal effects.At present,the quality of artificially cultivated P.polyphylla var.chinensis is uneven,so it is an important way to ensure the high quality and sustainable development of P.polyphylla var.chinensis by screening excellent provenances.In this study,P.polyphylla var.chinensis from different provenances in Hunan province and neighboring provinces and cities in the National Underforest Economic Demonstration Base of Hunan Academy of Forestry and the germplasm resource garden of Wanqing Breeding Cooperative in Xinning County,Hunan Province were used as research materials.Based on ITS sequence and psbA-trnH sequence of DNA barcode at molecular level,agronomic characters and medicinal components,the expression and characteristics of genetic differences among different provenances were explored,the differences among different provenances were analyzed,and the excellent provenances were selected.The results are as follows:(1)In the sequence of ITS,the sequence length of the tested provenances is 634-635bp,and there are some specific mutation sites in 7 provenances,such as Huitong,Wufeng,Huaying,Longshan,Guangze,Yongan,Huanjiang,which can be used as identification features to identify different provenances.The genetic distance is 0-0.0142,and the average genetic distance is 0.0034,which indicates that P.polyphylla var.chinensis from different provenances under ITS sequence has certain genetic diversity.Phylogenetic tree shows that all provenances are divided into two groups,A and B,and the genetic relationship among different provenances is related to their geographical distribution.(2)In the sequence of psbA-trnH,the sequence length of the tested seed source is 1024-1044 bp,and there is no specific mutation site.The genetic distance is 0-0.0127,and the average genetic distance is 0.0023.There are obvious variations only among provenances from Jishou,Baojing,Guangze and Yongan,which indicates that the intraspecific variation of psbA-trnH sequence is conservative and the genetic diversity is low.Phylogenetic tree shows that all provenances are divided into two groups,A and B,and there is no correlation between the genetic relationship among different provenances and their geographical distribution.(3)In the agronomic traits,the average coefficient of variation of the tested provenances is 22.56%,and the variation range is 9.74%-43.91%.The provenance with the greatest overall variation comes from Zhongfang,and the smallest comes from Longshan.The most variable trait is the length of petiole,and the smallest is the number of leaves.There are many significant correlations or extremely significant correlations between tuber length,tuber width,leaf length and leaf area and other traits.The test provenances can be divided into three groups,and the provenance from the third group has strong growth potential and typical high-yield characters.(4)In the medicinal components,polyphyllin Ⅰ,polyphyllin Ⅱ,polyphyllin Ⅵ,polyphyllin Ⅶ and total saponins are different among provenances.The contents of the five components are 1.303-11.286mg/g,0.372-3.708mg/g,0.000-0.581mg/g,0.203-4.815mg/g and 6.152-15.040mg/g,respectively,which indicates that their contents have a large variation range.The correlation shows that when polyphyllin Ⅰand polyphyllin Ⅱ are high,they often contain high total saponins in tubers.The test provenances can be divided into two groups:A and B,among which the provenances of Group A are characterized by low content of total saponins,and the content of medicinal components in most provenances can’t reach the average level.The provenances of Group B are characterized by high content of total saponins.Most provenances have higher than average content of medicinal components,but the content of polyphyllin Ⅵ is very low or not.(5)The excellent provenances screened out based on the membership function evaluation method are Xiushan,Taoyuan,Yongding,Liping and Yuanling.