The genetic diversity of wild Actinidia arguta germplasm resources from China and South Korea

Abstract:【Objective】Actinidia arguta is more and more famous for its nutritional value and medical value. China, especially the Changbai mountain area, is the main distribution area of A. arguta. Most of the wild A. arguta are dioecious plants, the genealogy was not well established during the course of cultivation, management and breeding. The origin and and pedigree of some new varieties (strains) was unclear. Distant hybridization has become an important way of germplasm innovation. Understanding the genetic background of Chinese and foreign wild A. Arguta is important for the improvement of the species via hybridization. RAPD markers were employed to study the genetic diversity of the germplasm resources of wild A. arguta from China and South Korea.【Methods】The leaf DNA of 28 wild A. arguta from Changbai Mountain region (24) and South Korea (4) was extracted by the plant genome DNA extraction kit of Solarbio company. Genomic RAPD-PCR was amplified using the following amplification systems and procedures: The system included 2 μ L, 10 × PCR buffer, 2 U Taq DNA enzyme, 0.25 mmol· L-1 d NTP, 2.0 mmol· L-1 Mg2+, 0.3 μ mol· L-1 primer, 40 ng DNA template, and dd H2O supplementation to 20 μ L. The PCR reaction was carried out on the BIO-RAD T100 TMThermal Cycler PCR instrument. The running amplification reaction program was as follows: an initial denaturation 94 ℃ for 5 min, denaturation at 94 ℃ for 1 min, annealing at 36 ℃ for 1 min, extension at 72 ℃ for 2 min, reaction of 40 cycles, last extension at 72 ℃ for 5 min. The same template was repeated twice. RAPD-PCR amplification products were analyzed by 0.8% agarose gel (0.5×TAE buffer) electrophoresis.【Results】The 24 primers had high genetic polymorphisms. A total of 191 bands were amplified, of which 186 were polymorphic bands, accounting for 97.4%. Average 7.75 polymorphic bands were produced by each primer. Genetic identity and genetic distance were calculated by NTSYSpc 2.10 e software and cluster analysis was analyzed by UPGMA. The result showed that the genetic distances among the 28 wild species of A. arguta germplasm resources were 0.020 2-0.934 2. When the genetic distance was0.58, the 28 wild species could be divided into two groups. The first group included Antu coloring type, Antu No. 1-6 from Antu County and Jiaohe No. 1-5 from Jiaohe. The second group include: Erdaobaihe No. 1-4 from Erdaobaihe; Wangqing No. 1-3 from Wangqing County and Wangqing Forestry Bureau;Zuojia No. 1-3 from the Zuojia special production Institute of the Chinese Academy of Agricultural Sciences (CAAS) ; Liaoning Huanren and Helong Qingshan; South Korea No. 1-4 from Chungbuk, Jeonnam and Gyeongnam in South Korea. The similarity of RAPD markers of Jiaohe 2 and 3, the two wild species reached 98 % when the genetic distance was 0.0202. Almost all the wild species from the same area belonged to the same category within a very small genetic distance. For example, Antu No. 1-6 were within the 0.184 genetic distance; Jiaohe No. 1-5 were within 0.18 genetic distance; Wangqing No.1-3 and Erdaobaihe No. 1 and No. 4 were within 0.315 genetic distance; Zuojia No. 1-3 was within 0.25 genetic distance; South Korea No. 1-4 were within 0.23 genetic distance; Erdaobaihe No. 2 and No. 3 were within 0.41 genetic distance.【Conclusion】There was a high genetic diversity among wild A. arguta collected from different geographic regions, but genetic diversity among those collected from the same geographical area was low. The genetic diversity of the wild A. arguta from South Korea was relatively low and was closely related to the wild A. arguta from Erdaobaihe, Wang Qing and Zuo Jia. The species collected from the same geographical area had the same clustering trend.