Genetic Divergence of the Chinese Fir Fast-growing Genotypes Revealed by SRAP Markers

In this study, sequence-related amplified polymorphism (SRAP) markers were used to genotype 32 fast-growing Chinese fir (Cunninghamia lanceolata) clones, and therefore evaluated the polymorphisms and genetic similarity, and generated a UPGMA dendrogram of the clones. The result indicated that 21 SRAP primer combinations produced 237 clear and stable bands, and notably, 214 of these were polymorphic. Different primer combinations seemed to have a divergent discrimination power in clones with NG (number of genotype identified) of 10-31. Based on the SRAP markers, the population diversity parameters of PPB (percentage of polymorphism band), PIC (polymorphism information content), GD (gene diversity), N_a (number of different alleles), N_e (number of effective alleles), I (Shannon′s information index) and H_e (expected heterozygosity) were found to be 90.3%, 0.218 7, 0.268 2, 1.903、1.392、0.380 and 0.243 respectively, reflecting a moderate degree of diversity in present Chinese fir collection. Impressively, the SRAP-based UPGMA tree help clarify the molecular genetic distance of the clones with a pairwise genetic similarity coefficient of 0.400 0-0.599 9 for most (95.5%) of the clone pairs. Briefly, it could be concluded that there still has large amount of variation among clones (n=32), albeit a restricted selection for their growth traits (fast-growing). Intra-population (n=32) reselection and crossing is rather promising for this collection.