Studies On Genetic Diversiy Of Germplasm Resources In Genus Paulownia By ISSR Marker

Paulownia, native to China, is a kind of important fast-growing trees providing with wood. The germplasm resources are extraordinary abundant such as species,varieties, morphological variation, and elite clones in China, due to. mutation and creating a hybrid etc. In order to make clear relationships between species, varieties, as well as genetic differences within plants in Paulownia. Inter-simple sequence repeat(ISSR) markers was employed to analyze genetic similarity and relationship within these 45 accessions includes species,varieties, morphological variation, and clones.of Paulownia, aiming to provide scientific basis for the Classification and identifieation of plants in Paulownia. At the same time, to provide references for the Paulownia systemamtics of intraspecies and interspecies of Paulownia fortunei, as well as genetic variations and genetic diversity among 38 provenances of Paulownia fortunei were evaluated by the same means in this paper. In order to offer some molecular biology theories on breeding of elite provenance and plants and hybridization breeding. in Paulownia fortunei. The main results were summarized as follows:(1) ISSR-PCR optimization reacting system of Paulownia, in a total volume of 20μl included the following components:1×buffer, template DNA of 40ng, Mg2+ of 1.5mmol/L, dNTP of 0.30mmol/L, primer of 0.4μmol/L, and Taq polymerase of 1U. (2)The ISSR fingerprintings of 45 accessions in genus Paulownia were consrtucted, and proved that ISSR were a very effective tool and robust method in accessions discrimination in Paulownia There were 2 independent ways t o identify these 45 accessions (unique band pattenrs and a eombination of the band pattenrs provided by dieffrent Primers.The result showed the cultivars had unique ISSR fingerprinting, (Figures in brackets refer to serial number in table 2.1)①P.fortunei (4):P855-1400bp, P855-850bp, P810-950bp②P.fargesii (5):P807-2000bp, P807-850bp, P834-1700bp③Morphological variation types of P.tomentosa:P807-960bp P836-1700bp, P880-2000bp④Morphological variation types of P. tomentosa8 (26):P834-800bp⑤Morphological variation types of P.fortunei:P811-3000bp, P815-2700bp, P810-550bp⑥Morphological variation types of P.fortunei 4 (27):P815-3000bp⑦Elite tree of P.fargesii1 (35):P810-250bp(3) Results from ISSR maker researches on genetic diversity of 45 plants in Paulownia.9 out of 100 primers were screened, and total 109 fragments were amplified of which 103 bands are polymorphic. Percentage of polymorphic loci(PPL) among different primer was between 80%and 100%. Genetic Identity is ranging from 0.37 and 0.85, the mean observed number of alleles (Na), the mean effective number of alleles (Ne), the mean Nei's gene diversity index (H) and the mean Shannon's Information index (I) of Paulownia were 1.9541,1.5391,0.3154,0.4744, respectively, indicating the genetic diversity among Paulownia is in rich.UPGMA cluster analysis showed clear genetic relationship among 45 accessions in Paulownia. The genetic relationship among P.elongata, P. lamprophylla and P elongata f.albais is close, then P elongata f. alba is the variation of P.elongata. P.catalpifolia, P.henanensis, P.ichangensis, and P.tomentosa var. lucida all have the close relationship with P. tomentosa. Meanwhile P.catalpifolia is variaty of P. tomentosa, then P.catalpifolia and P. tomentosa was created a hybridation of P.henanensis. Both P.tomentosa var. luci a and P.ichangensis are independ species. The group with close relationship is consist of P.australis, P.albiphloea, P.jianshiensis and P.albiphloea var.chentuensis. Another group with close relationship is consist of P.fortunei, P.fargesii, P.kawakamii, Which illustrates P.australis and P.kawakamii are different species. A PCoA analysis has similar divisions with cluster analysis.(4) Results from ISSR maker researches of 38 provenances of P.fortunei9 out of 100 primers were screened, and total 95 fragments were amplified of which 88 bands are polymorphic. Percentage of polymorphic loci(PPL) among different provenances was between 32.63%and 56.84% with the average of 47.16%. Genetic Identity is ranging from 0.39 and 0.82, the mean observed number of alleles (Na), the mean effective number of alleles (Ne), the mean Nei's gene diversity index (H) and the mean Shannon's Information index (Ⅰ) between provenances of P.fortunei were 1.8571,1.3910,0.2424,0.3765, respectively, The coefficient of Population differentiation(GsT) was 0.4716. It is estimated that the genetie variation between and within provenances respectively account for 47.16%, and 52.83%, indieating that the genetie variation between provenances was higher than that of within provenances.38 provenances of P.fortunei could be divided into 5 major groups obviously based on the UPGMA cluster analysis. A rotated PCoA plot with the markers as observations was used to determine the 4 big groups based on Eigen values>1.