Genetic diversity and relationships of ancient Chinese fir (Cunninghamia lanceolata) genotypes revealed by sequence-related amplified polymorphism markers

Some more than a century old Chinese fir genotypes with high biomass that are now rare in China were historically called "the king of Chinese fir". The genetic diversity and relationships of those ancient Chinese fir genotypes were investigated using morphological analysis and sequence-related amplified polymorphism markers. The morphological analysis indicated that the tree volume parameter had the maximum variable coefficient value (70.2 %). In total, 18 selected primers generated 154 bands, and 150 bands were polymorphic (97.4 %). Higher values of genetic diversity parameters (h = 0.3593, I = 0.5283) were maintained at the species level, indicating that the ancient Chinese fir in China has retained a relatively high level of genetic diversity. AMOVA indicated that 73.16 % of the variation resided within provenances. The UPGMA dendrogram and genetic structure analysis identified 3 major clusters and grouped the genotypes in agreement with their geographic origins. A Mantel test revealed a significant correlation between genetic distances and geographic distances among the genotypes (r = 0.4275, p < 0.01). Overall, we recommend a combination of conservation measures including a germplasm repository and the implementation of in situ conservation.