RAPD Analysis of Germplasm Resources of Kudingcha Species in Oleaceae

The random amplified polymorphic DNA marker (RAPD) was applied to detect the genetic relationships and diversity among 21 germplasm materials of Kudingcha species in Oleaceae, which involved 8 species, i.e., Ligustrum robustum (Roxb.) Blume, L. henryi Hemsl., L. japonicum Thunb, L. japonicum Thunb. var. pubscens Koidz, L. lucidum Ait., L. pedunculare Rehd, Osmanthus masumuranus Hayata, and L. delavayanm Hariot. 20 RAPD primers selected were applied for the amplification on the 21 germplasm materials mentioned above. 427 bands were obtained, and the percentage of polymorphic bands (PPB) was 97.7%. The genetic similarity coefficients (GS) ranged from 0.1522 to 0.8322 with an average of 0.5466. There was a significant genetic difference among germplasm materials of Kudingcha species in Oleaceae, and UPGMA cluster based on the GS of RAPD could distinguish all test germplasm materials clearly and indicated the relationship of the 8 species mentioned above, all of which indicated that RAPD markers could be used for the studies of genetic diversity and relationship and classification of germplasm resources of Kudingcha species in Oleaceae. Analysis results of RAPD showed that L. japonicum Thunb. var. pubscens Koidz has closer genetic relationship with L. pedunculare Rehd and further genetic relationship with L. japonicum Thunb. among all tested species. The authors suggest that further research is needed to study whether L. japonicum Thunb. var. pubscens Koidz should be classified into a variata of L. japonicum Thunb, or should be considered as an independent species. The analysis results supported that L. pururascens Y. C. Yang should be combined into L. robustum (Roxb.) Blume.