Genetic Diversity Of Bursaphelenchalis And Its Correlation With Geographical Climatic Factors

Buffalograss (Buchloe dactyloides(Nutt.)Engelm.) is a kind of herbaceous plant which belongs to Gramineae buffalo grass. It is native to the temperate and subtropical central semi-arid regions of North America, with strong drought tolerance, heat resistance and resistance to disease, is one of the important warm-season grass lawn, it has been widely used in China, especially in arid northern region. Germplasm collection of Buffalograss and genetic evaluation it, will lay the foundation for screening excellent buffalograss breeding material, establishment of core germplasm bank, further cultivate new varieties. In this study,177 high-quality material from 61 parts of prairie which is the orgin for Buffalograss were used as objects of study, major in study the genetic diversity and distribution patterns from morphological level, ploidy level and molecular level. And analyze the correlation between phenotype, ploidy, molecular markers and buffalograss habitat geography, climatic factors. The main research results are as follows:(1) Bisongrass germplasm had extensive phenotypic diversity, there were significant variations of each phenotypic traits of bisongrass between populations within and among populations, mainly from within populations. Cluster analysis within 4 morphometric indicators demonstrate that there were 4 clustering results, which are coincide with the actual level of the geographical distribution of the population.(2) Through the ploidy determination for bisongrass germplasm by flow cytometer, indicate the most suitable flow cytometry cell lysates for bisongrass is magnesium lysates. The measurement results showed that all the materials of a total of 4 ploidy, they were diploid, tetraploid, pentaploid and hexaploid. Among them tetraploid and hexaploid are of larger number and wider distributed, diploid and pentaploid accounted for less.(3) For the first time capillary electrophoresis is used to analyze SRAP genetic diversity in 177 copies of bisongrass. In this experiment the ratio obtained SRAP polymorphism (PPB) was 99.84%. GS value based on Nei-Li similarity coefficient (GS) similarity analysis of each material in the 0.228-0.885, the average value of GS was 0.465, showed bisongrass germplasm abundant genetic diversity. All buffalograss germplasm coefficient of genetic differentiation (Gst) was 0.116, that is a variation of bisongrass between each group accounted for 11.6%, description of genetic variation within the major groups of bison grass dominated variation.(4) Bisongrass in morphology and phenotype correlation ploidy analysis showed, the greater ploidy level, means the larger phenotypic characteristics of bisongrass. In the bisongrass morphology and phenotype correlation analysis of geographical and climatic factors indicate that bisongrass of phenotypic traits and the annual average temperature and annual rainfall was a significant positive correlation, that’s to say the greater phenotypic characteristics of bison grass materials under high temperature and humid climate characterized by growth. The parameters of genetic diversity in groups based on eco-geographical analysis of the correlation between morphological phenotype of buffalo grass and SRAP markers indicate section between leaf width and diameter variation mainly from the genetic differentiation.Comprehensive study results can be seen, in morphological level,DNA ploidy level and molecular, buffalograss germplasm are more abundant in genetic diversity, genetic variation and its wide geographical distribution and environmental factors are closely related.