Studies On Genetic Diversity And Phylogenetic Relationship Of Ornamental Germplasm Resources In Bougainvillea

Bougainvillea belongs to the Nyctaginaceae with18species in the world. ItsOrnamental Germplasm posses300varieties or so including protospecies, varieties,cultivars and hybrids, and mostly originated from B. glabra, B. spectabilis and B.peruviana, however, about100varieties in China. At present, although there are a fewreports on the molecule study of Bougainvillea, especially on genetic diversity ofDNA level, single method is generally used in those researches. The development andultilization of the resourses of Bougainvillea are restricted to a certain degree. Thegenetic diversities and phylogenetic relationship of48Bougainvillea cultivars basedon RAPD, ISSR and SRAP molecular markers were studies in this dissertation. Themain results are as follows:1. The DNA extracted by the modified method of CTAB can completely meetwith the experiments related to RAPD, ISSR and SRAP marker.2. By using single-factor test and orthogonal design, the reaction system ofRAPD, ISSR and SRAP fitting for analyzing the genetic diversity of Bougainvilleawere established and optimized.3. The genetic diversity of48samples was revealed by RAPD, ISSR and SRAPmolecular markers. Seven RAPD random primers amplified a total of97DNA loci,percentage of polymorphic loci is100%. Polymorphism information content (PIC),observed number of alleles, effective number of alleles, Nei’s gene diversity andShannon’s information index were respectively0.890,2.0000,1.4595,0.2803,0.4340.Eleven ISSR primers amplified a total of140DNA loci, percentage of polymorphicloci is100%. Polymorphism information content, observed number of alleles,effective number of alleles, Nei’s gene diversity and Shannon’s information indexwere respectively0.835,2.0000,1.4189,0.2579,0.4040. Twenty-five pairs SRAPprimers amplified a total of773DNA loci, percentage of polymorphic loci is97.02%.Polymorphism information content, observed number of alleles, effective number ofalleles, Nei’s gene diversity and Shannon’s information index were respectively 0.9463,1.9702,1.4721,0.2818,0.4314. A high genetic diversity level was revealedby above parameters, and the ability of molecular marker from top to down is: SRAPmarker>ISSR marker> RAPD marker.The results of UPGMA dendrogram of48samples based on RAPD, ISSR andSRAP markers show that every sample of them can be made a distinction. However,the different results of group delimited are made because of various methods above.The ISSR is more accordant with the SRAP than with RAPD. Mostly, phylogeneticrelationships are very near. In spite of few cultivars, the samples generally originatedfrom two germ lines, of one from B. glabra, another from species including B.spectabilis, B. peruviana, B.×buttiana and B.×spectoglabra. The resolution of themolecular markers is much higher than morpho-agronomic characters to identifyindividual cultivars. Intriguingly, the cluster pattern based on the data of RAPD, ISSRand SRAP is almostly indiscriminating to that on the data of only SRAP. This impliesthat the stability and polymorphism of SRAP superior to those of RAPD and ISSR.