Researches On Genetic Diversity Of Half-sib Families Of Ginkgo Biloba L. With SRAP

Ginkgo biloba L. is the only remained species in Ginkgopsida and known as a "living fossil", therefore its genetic resources is very precious and the research of which is of both great theoretical and practical significance. China is the native land of Ginkgo biloba, Hubei province has abundant ginkgo resources. In this paper, researches on genetic diversity of36half-sib families of Ginkgo biloba collected from Hubei were carried out with SRAP molecular marker technique. Main results were as follows:(1) Eight SRAP primer pairs screened out from100primer pairs were used for PCR amplification of the180samples. A total of62bands were produced,60of which were polymorphic bands and the percentage of polymorphic band was96.77%. The number of bands produced by each primer ranged from5to12, and the number of polymorphic bands produced by each primer was from5to11.(2) Analysis on indexes of genetic diversity showed:①The percentages of polymorphic band (PPB) of the families were from41.46%to3.23%, the average was21.47%, the highest occurred in ZY49and the lowest in ZQ37, the difference is38.23%;②the observed number of alleles (A) was in the range of1.0161to1.3065, with the highest in ZY49and the lowest in ZQ37, and the mean was1.1362;③the effective number of alleles (N) was in the range of1.0158to1.2184, with the highest in ZY49and the lowest in ZQ37, and the mean was1.0961;④the Gene diversity index (H) was in the range of0.0532to0.008, with the highest in ZY49and the lowest in ZQ37, and the mean was0.0533;⑤The Shannon’s information index (I) was in the range of0.1645to0.0111, with the highest in ZY49and the lowest in ZQ37, and the mean was0.0780;⑥In addition, the order of indexes A, N, H and I was basically identical.(3) The comparison of genetic diversity between5family groups from4counties or cities showed that the highest genetic diversity occurred in Kedian group with8half-sib families.(4) The genetic similarity coefficient of the36half-sib families was in the range of0.57to0.98, and that between ZY46and ZY47is the highest (0.98). Cluster analysis indicated that most families grouped geographically. (5) There were rich genetic diversity within ginkgo families, and the genetic diversity of different families differed. It suggested that to protect ancient ginkgo trees according to their genetic diversity. For example, ZY49and ZY48which have higher genetic diversity, should be protected with precedence and special measures.