Analysis Of Broussonetia Papyrifera Group Based On Morphology,Physicochemical Properties And SSR Marker

Plant group is the result of the integrated effect of genetic diversity and environment,which not only reflects the evolutionary pattern and history of species,but also enables a deeper analysis of its future evolutionary direction and potential.Broussonetia papyrifera as an important economic tree species and an important environmental plant,it has broad development prospects,and the research on its germplasm resources and genetic diversity is very essential.In this study,B.papyrifera resources collected from 6 provinces,11 counties(cities),17 samples in China were used as research materials,which were studied and evaluated from the aspects of phenotypic traits,component content,and physicochemical properties.At the same time,the genetic diversity was analyzed by SSR marker.The main findings of the study are as follows:(1)The diversity of B.papyrifera phenotypic traits can intuitively reflect genetic diversity.The leaf phenotypic traits of the 17 provenances were rich in variation,with an average coefficient of variation of 31.607 and a range of 19.667%-44.872%.The 6 phenotypic traits were ranked as follows:shape factor>Leaf petiole>leaf perimeter>leaf area>leaf width>leaf length.In addition,the six phenotypic traits of B.papyrifera had high correlation,which was a certain correlation between phenotypic traits and environmental factors such as temperature and latitude.According to the phenotypes of B.papyrifera leaves,they were clustered into four categories,among which leaf area,leaf length,leaf petiole,leaf perimeter and shape factor were the dominant factors in the clustering of B.papyrifera resources.(2)The nutrient element content of B.papyrifera leaves of different provenances has rich variation,among which the variation coefficients of 8 nutrient elements content range from 17.360-118.875%,with high degree of variation.The order of variation degree is as follows:Mn>P>Fe>Zn>Mg>Ca>N>K.In addition,there is a strong correlation between the contents of nutrient elements in B.papyrifera leaves,which was a certain correlation between Ca,Mg,K content and environmental factors.According to the element content of B.papyrifera leaves,they were clustered into 4 categories,among which Fe,Mn and Ca content were the dominant factors in the clustering of B.papyrifera resources.(3)The B.papyrifera leaves of different provenances have a high degree of variation in physiological and biochemical levels.The average coefficient of variation of protein,POD,flavonoid,and phenolic content was 61.965,and the range was 33.683-86.946%.The order of the coefficient of variation from large to small is:POD>flavonoid>phenol>protein.In addition,there were high correlations among protein,POD,flavonoid and phenolic contents in B.papyrifera leaves,which was a certain correlation between environmental factors such as altitude,longitude and latitude.According to the physiological and biochemical characteristics of B.papyrifera leaves,they were clustered into three categories,among which POD activity,total phenols,protein,and total flavonoids were the dominant factors in the clustering of B.papyrifera resources.(4)SSR marker technology has a high detection efficiency for the genetic diversity of B.papyrifera resources,and reveals the richness of B.papyrifera resources of different provenances at the genetic level.The study showed that each primer amplified 3.75 alleles on average,the average number of effective alleles was 2.189,the average value of Shannon’s index was 0.815,and the average value of polymorphic information content(PIC)was 0.421.According to the results of SSR markers,they were clustered into three groups.In addition,by comparing the clustering results of phenotypic traits,component contents,physiological,biochemical characteristics and genetic characteristics of B.papyrifera resources,it can be seen that the types of B.papyrifera resources,growth environment and other factors have a certain impact on the clustering results.The phenotypic traits,component content,physiological and biochemical characteristics of B.papyrifera resources with the same genetic clustering will also be affected by the environment.This study explored the genetic differences of B.papyrifera resources among different provenances from multiple levels,revealed the genetic relationship between B.papyrifera from different provenances.It provides a reference for the cultivation,protection and utilization of excellent B.papyrifera germplasm,and provides an important scientific basis for exploration of germplasm optimization and genetic improvement of B.papyrifera.