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Study On Genetic Diversity Of The Worldwide Wild Trifolium Repens Germplasm Resources

Posted on:2014-06-02Degree:MasterType:Thesis
Country:ChinaCandidate:J Y ZhangFull Text:PDF
GTID:2253330425951162Subject:Grassland
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White clover(Trifolium repens) is legume (Leguminosae) clover (Trifolium) perennial herb with relatively abundant agronomic characters in the world.In this study,70wild Trifolium repens germplasms are collected in30countries as the experiment materia. Genetic diversity was studied through phenotype, SRAP molecular markers and SSR molecular marker. The main results were as follows:(1) The tested white clover germplasm phenotypes have obvious difference and rich diversity. The plant height variation coefficient is as high as67.13%; The ordinal number is leaf area and flowers ordinal number per unit area with the variation coefficient61.85%and59.95%respectively; Reproductive shoot height coefficient of variation is relatively high, and it is34.60%; Variation of number of florets per spike was smaller, and the coefficient of variation is25.84%. Among plant height, reproductive shoot height, leaf area and florets per spike, it exists the extremely significant positive correlation (P<0.01). While between flowers ordinal number per unit area and the other four indexes it presents the extremely significantly negative correlation (P<0.01). Based on phenotypic traits clustering, the tested white clover germplasm can be divided into three large groups. Materials from East Asia, Central and SouthernEurope, West Asia germplasm were respectively divided into one category, and the three groups have obvious morphological differences.(2) Using SRAP molecular markers, research genetic diversity and phylogenetic relationship of the70wild white clover germplasm. The results show that using SRAP molecular markers can be detected more genetic loci. Screen26random primers combination from240pairs of SRAP primer combinations to amplify a total of429legible bands, including372polymorphic bands, average each pair of primers14.31, polymorphismlocus (PPB)86.71%;The tested material polymorphic information content (PIC) range of0.1660-0.4276revealed by26pairs of SRAP primer combinations; Labeling index (MI) of screened SRAP primer combinations is1.0495-9.9282. GS value of the tested70wild white clover germplasm is0.5291-0.9207, an average of0.6618, genetic distance GD (1-GS) from0.0793to0.4709, ranged from0.3916. The materials PI634088and PI634079from the USA have the biggest genetic similarity coefficient for0.9207, indicating the closest relationship of the two materials; while the materials PI634079from the United States and PI204514from Turkey have the smallest genetic similarity coefficient for0.5291, indicating that the farthest kinship of the two materials. Based on the genetic similarity coefficient of Nei-Li and according to the UPGMA method (unweighted group average method),cluster analysis and principal component analysis showed that70parts of white clover material can be divided into three categories of southeast Asia, West Asia and the Caucasus and Europe, North Africa and North and South America on the genetic similarity coefficient level of0.674.Cluster the same geographic groups and the origin of the material into one group,showing the discipline of geographical distribution.(3) Using SSR molecular markers, study genetic diversity and phylogenetic relationships of70white clover. The results showed that SSR markers can be detected more white clover genetic loci and is an effective marking methods to analysis white clover genetic diversity.Screen20pairs of primers form the42pairs SSR primer to amplify a total of203legible bands, including181polymorphic bands, average each pair of primers10.15, polymorphismlocus (PPB)89.16%; polymorphic information content (PIC) range of0.1660-0.4276, average0.3342; The genetic similarity coefficient of70white clover material is0.4974-0.9458, and the GS for an average is0.6613ranging from0.4484. PI180491and PI414366from South India with the minimum similarity coefficient for0.4974, indicating the closest relationship of the two materials; According to the cluster analysis of UPGMA method and principal component analysis in the0.662level for the tested white clover can be divided into3categories of Asia and the Caucasus, Europe and north Africa, and the same materials of geographical groups can be clustered into one group.
Keywords/Search Tags:Trifolium repens, morphological character, SRAP molecular markers, SSRmolecular markers, genetic diversity
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