Studies On Genetic Diversity Of Ginkgo Germplasm Resources Based On AFLP Technique

Ninety germplasms of Ginkgo biloba from foreign and domestic countries were used as tested materials, genomic DNA of them were extracted using the cetyltrimethyl ammonium bromide (CTAB) method. Seven-eight primer combinations that produced clearly and highly polymorphic bands were screened from 64 EcoRI/MseI primer combinations (MseI fluorescent labeled). The genetic diversity of 90 germplasms of G. biloba from the U. S., Holland, Japan, France and China was analyzed. Band patterns were dealt with Genescan3.1 software (Apllied Biosystems, Foster city, CA. USA), the binary data matrix was constructed. The Dice similarity coefficient (SC) matrix was obtained by using NTSYS.pc2.11f software (Apllied Biosystems, Setauket, NY. USA), and cluster analysis based on SC matrix was performed with unweighted pair-group methods of arithmetic averages (UPGMA). The results were obtained as following:Genetic diversity of ornamental cultivars of G. biloba: The genetic diversity of twenty-one G. biloba ornamental cultivars from the U S, Holland, Japan, France and China was analyzed with 8 primer combinations. These primer combinations produced a total of 1119 bands, 229 specific loci (including 54 absent bands, 175 monomorphic bands), 983 polymorphic bands, the percentage of polymorphic bands(PPB) was 88%, and the identification percentage (IP) per primer combination was 100%. Genetic similarity coefficient (SC) among all cultivars varied from 0.49 to 0.84, and all cultivars were divided into four clusters when SC was set at 0.73. The cultivars from the same origin did not fall into the same group. The cultivars from France and China were classified into three groups, respectively. According to the comprehensive analysis based on specific loci, similarity coefficient, and clustering results, 8 cultivars'Fastigiata','Tit','Tubifolia','Daeryinxing','Variegata','Horizontalis,'Pendula', and'Yiyuanyeziyinxing'were considered to be important germplasms of ornamental cultivars of Ginkgo biloba. The average PPB (35.86%) of 14 foreign G. biloba ornamental cultivars was higher than that (31.51%) of 7 domestic G. biloba ornamental cultivars.