Application Of RAPD In The Study Of Genetic Diversity And Systematics Of Ulmus Pumila Var.sabulosa

U. pumila var. sabulosa, whose classified position was disputed, is one of native trees in Hunshandake sandland, and plays an important role in recovering and regenerating of grasslands ecological system. In this thesis, RAPD technique was used to study U. pum i/a var. sabu/osa, trying to determine its systematic position and level of genetic diversity. The results are as follows:(1) 16 effective primers were used to amplify genomic DNA samples of six U. pumila var. sabulosa populations and two contrasted populations of U. pumi?a. Altogether 115 fragments were produced, among which 49 fragments (at a proportion of 42.6%) were polymorphic at the level of population, above the statistical average value(34%), and 89 fragments(at a proportion of 77.4%) showed polymorphism at individual level. (2)Cluster analysis (UPGMA) was performed on genetic distance. At the level of population, when threshold value was 0.1, populations of U. pum i/a var. sabu/osa and contrasted populations can be sorted into 2 different groups. The result demonstrated that U. pum i/a var. sabulosa can be regarded as a variety of U. pum i/a. Cluster analysis of individual level indicated that there was certain differentia among populations of U. pum i/a var. sabu/osa, which was related to geographical distribution. (3)By means of genetic diversity index analyzing, it was indicated that there was clear genetic differentia in populations of U. pum i/a var. sabu/osa, and coefficient of gene differentiation was 0.20, which indicated U. pum i/a var. sabulosa has relatively high level of differential potentialities within populations. The results of this thesis demonstrates applicability of RAPD in the study of genetic diversity and systematics of U. pum i/a var. sabulosa was practicable. Furthermore, the relation between genetic diversity and breeding system of U. pumila var. sabulosa was discussed.