Genetic relationship analysis and core collection construction of Eucalyptus grandis from Dongmen improved variety base: the largest eucalypt germplasm resource in China.

BACKGROUND: Eucalyptus grandis, which was first comprehensively and systematically introduced to China in the 1980s, is one of the most important fast-growing tree species in the forestry industry. However, to date, no core collection has been selected from the germplasm resources of E. grandis based on growth and genetic relationship analysis. RESULTS: In the present study, 545 individuals of E. grandis collected from 28 populations across 5 countries were selected for genetic diversity analysis using 16 selected SSR markers. The polymorphism information content (PIC) was employed to assess genetic diversity, yielding a mean value of 0.707. Genetic structure analysis was conducted on 492 individuals from 13 combined populations, revealing three clusters as the most suitable number. Principal coordinate analysis (PCoA) demonstrated that the populations were divided into three major clusters. Additionally, the analysis of molecular variance (AMOVA) indicated that the majority of variation occurred within populations. CONCLUSIONS: Based on the criteria for screening the core collection, we constructed a population consisting of 158 individuals and created unique fingerprinting codes. These results provide a crucial theoretical foundation for the protection and utilization of germplasm resources of E. grandis in China, which will be helpful in the selection of genetically distant parents for future multigenerational hybridization programs.