Application of microsatellite DNA on analyzing genetic diversity of Juglans regia

In order to study genetic diversity of different walnut varieties and to provide theoretical basis for breeding new varieties and obtaining new germplasm resources, the genetic diversities of the 18 Juglans regia species(including three strong and good seedling varieties) in nursery garden of North West Agriculture and Forestry Un iversity were studied by using SSR molecular marker technology. The PCR optimum system was set up; 12 primers with good repeatability and strong polymorphism were screened out from 27 primers; 174 bands were amplifi ed out totally, in which 118 were pollymorphism bands, accounting for 67.82% of the total, the averaged number of the polymorphic loci of each primer was 9.8. The similarity coeffi cient between Xinjiang 2 and Liaoning 4 was the maximum(0.803 6), that between Qinglin and Xilin 2 was minimum(0.159 4),the averaged value of the similarity coeffi cient was 0.815 0. Polymorphic information contents(PIC) ranged from 0.742 2 to 0.896 2, and all values were greater than 0.500 0. The cluster analyses with UPGMA method show that the 27 germplasm could be divided into 4 groups. It was indicated that 15 primers sites showed a high degree of polymorphism, also showed that the genetic resources of these samples were very rich.