Development of EST-SSR Markers and their Use in Assessing Genetic Diversity in Chinese Fir Infusion Populations

In advanced-generation tree breeding program, infusion populations are often used as an effective method to expand and maintain genetic diversity. To analyze the genetic diversity and population structure of six Chinese fir (Cunninghamia lanceolata) geographical populations, a total of 20 expressed sequence tag-derived simple sequence repeat markers pairs (EST-SSR) were developed and applied for genetic diversity analysis. The evaluated populations exhibited moderate genetic diversity with the following parameters: number of alleles (Na: 4.850), effective number of alleles (Ne: 2.920), information index (I: 0.958), observed heterozygosity (Ho: 0.319), expected heterozygosity (He: 0.481), unbiased heterozygosity (uHe: 0.496), and fixation index (F: 0.321). The analysis of molecular variance (AMOVA) suggested that only 9.42 % of genetic variation existed among populations, whereas the majority (90.58 %) resided within populations. Cluster analysis showed one population (Sichuan Dechang) as a separate taxon, likely due to its geographical isolation. The present study demonstrated the effectiveness of the developed EST - SSR in analyzing genetic diversity for population.