Genetic diversity and population structure analysis of wild kiwifruit (Actinidia spp.) using SRAP markers

Southwest China is one of the most concentrated regions of wild kiwifruit germplasm. With the increased instances of extreme weather and the impact of human activities, the wild kiwifruit population is being destroyed. However, there is little research on the wild kiwifruit resources. Therefore, strengthening research on wild resources of kiwifruit and determining the genetic diversity of kiwifruit are essential. In this study, 110 wild kiwifruit germplasms were collected as test materials. We selected 13 primers out of 256 pairs to analyze the genetic diversity. A total of 178 loci were amplified, including 175 polymorphic loci, accounting for 98.31%. The genetic similarity coefficient ranged from 0.551 to 0.905, with an average of 0.721. The effective allele number (Ne), Nei's gene diversity index (H) and Shannon's information index (I) were 1.452, 0.245 and 0.439, respectively. Very low genetic differentiation (Gst: 0.051) and very high gene flow (Nm: 11.899) were observed. When the genetic similarity coefficient was 0.652, the kiwifruit germplasms were divided into four categories, and the geographical distribution of samples in different categories was inconsistent. The result of principal coordinate analysis (PCoA) and structure analysis showed that the population of wild kiwifruit was divided into two subgroups. Our research contributed to identifying the genetic background of wild kiwifruits in Guizhou Province, China, and can be an important reference for the protection of wild kiwifruit and the breeding of new kiwifruit varieties.