Understanding genetic diversity and structure in natural populations and their suitable habitat response to environmental changes is critical for the protection and utilization of germplasm resources. We evaluated the genetic diversity and structure of 24 A. chinensis populations using simple sequence repeat (SSR) molecular markers. The potential suitable distribution of tetraploid A. chinensis estimated under the current climate and predicted for the future climate was generated with ecological niche modeling (ENM). The results indicated that the polyploid populations of A.chinensis have high levels of genetic diversity and that there are distinct eastern and western genetic clusters. The population structure of A. chinensis can be explained by an isolation-by-distance model. The results also revealed that potentially suitable areas of tetraploids will likely be gradually lost and the habitat will likely be increasingly fragmented in the future. This study provides an extensive overview of tetraploid A. chinensis across its distribution range, contributing to a better understanding of its germplasm resources. These results can also provide the scientific basis for the protection and sustainable utilization of kiwifruit wild resources.

Kiwifruit belonging to the Actinidiaceae family is a perennial, dioecious vine called ‘the king of fruits’ due to its considerably nutritious and sweet characteristics. A. chinensis complex, including two main groups, A. chinensis var. chinensis and A. chinensis var. deliciosa, is a major component of Actinidia due to their huge economic value and the high degree of development and utilization. Wild resources are widely distributed in China, but are under serious threat due to extreme environments and destroyed habitats. Thus, it is of great significance for the conservation of kiwifruit resources and the sustainable development of the kiwifruit industry to evaluate the genetic diversity of existing genetic resources and to systematically construct a core collection of the A. chinensis complex. In this study, 40 high polymorphism microsatellites markers were used to investigate all accessions from the A. chinensis complex. A total of 888 alleles were marked with 22.2 alleles in each locus. The expected heterozygosity was 0.846, the observed heterozygosity was 0.622, the polymorphism information content was 0.835, and the Shannon information index was 2.369. Among these loci, the observed heterozygosity of 38 loci was lower than expected. The inbreeding coefficient was 0.257, which indicates that frequent hybridization occurred between close relatives. Analyses of molecular variance showed that genetic variations mainly came from the population. Finally, a core collection containing 93 accessions was constructed. The bank not only perfectly represented the genetic diversity of the original population, but also had excellent potential for development and utilization. Our research provides a crucial reference for the future conservation, germplasm identification, and genetic breeding of kiwifruit.

Actinidia latifolia, with the highest vitamin C content in its genus, is a unique wild relative of kiwifruit that could be important for genetic breeding research. Climate change significantly influences the distribution range of wild plants. Accurately assessing the potential distribution of wild kiwifruit and its response to climate change is crucial for the effective protection and sustainable utilization of its germplasm resources. In this study, we utilized the optimized MaxEnt model to predict the potential habitats of A. latifolia in China, employing the jackknife test to assess the importance of environmental variables in our modeling process. The results showed that annual precipitation (Bio12) and temperature annual range (Bio7) emerged as the most influential environmental variables affecting the distribution of this kiwifruit wild relative. As radiative forcing and time increase, the potential habitats of A. latifolia in China are projected to shrink southward, thereby exacerbating habitat fragmentation. This research offers significant scientific references for the investigation, protection, cultivation, and application of wild relatives of the kiwifruit.