Genetic Diversity In Populations Of Ginkgo Biloba.L Detected By RAPD And ISSR

Ginkgo biloba L., which is now unique in Ginkgopsida, is referred as a"living fossil" plant. And it has high economic and scientific values.75 individuals of 5 populations, including possible wild populations inside of China were analyzed by random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) markers to determine the genetic diversity and genetic variations of among and within the populations.from this study, the conclusions were as follows:1 A total of 65 loci were amplified using 12 random primers for RAPD and a total of 68 loci were amplified using 12 ISSR primers for ISSR.The average percentage of polymorphic bands (PPBs) are 72.06% for ISSR and 66.67% for RAPD respectively. The genetic diversity of ginkgo revealed by ISSR (the average effective number of alleles is 1.8780, the average Nei's gene diversity is 0.4652, and the average Shannon's information index is 0.6574) are all higher than those by RAPD (the average effective number of alleles is 1.7842, the average Nei's gene diversity is 0.4317, and the average Shannon's information index is 0.6211), while the standard errors of the parameters estimated by ISSR were lower. Therefore, ISSR molecular markers are more suited than RAPD molecular markers when testing the genetic diversity of ginkgo populations and determining the genetic relationship of among populations or among individuals which are much similar hereditarily.2 The five nature populations of ginkgo have higher genetic diversity than the cultivated populations through ISSR and RAPD analysis. The populations of DH,TM,WC,JF have the most genetic diversity, which are regarded as the survival habitats in glacial period.3 The genetic variation among the natural populations of ginkgo revealed by Nei's analysis , Shannon's information index analysis and analysis of Molecular Variance (AMOVA)( ISSR :Gst=0.1955, ([Isp-Ipop)/ Isp]= 0.1903,φST= 17.63%;RAPD:Gst=0.2882, [(Isp-Ipop)/ Isp]= 0.2949,φST=36.69%) was greater than other kinds of anemophilous plants. The genetic differentiation among populations might be caused by human selective pressures and barriers of geography. The anlysis of UPGMA cluster among the five natural populations showed that: except the population of WY, the other populations have similar hereditarily,and the populations of TM,DH have the most similar hereditarily.4 It suggested that the protected of natural populations should be combined with in situ and transferred because of a certain extent genetic variation among the natural populations. The populations of DH, TM and WC are the concentration places of wild Ginkgo biloba L.. Among these populations, there are a great numbers of seedlings, which have more strong renovative ability .Therefor, these are the best regions to protect the gentic diversity using combined with in situ and transferred and should establish conservation areas in these places.