Eight Juglans populations (4 populations of J. sigillata and 4 of J. regia), which are distributed in Yunnan, Sichuan, Henan, and Shanxi Province, were selected to investigate their genetic structure and diversity using 8 microsatellite loci. A moderate level of genetic diversity was observed at population level by the total 71 of alleles. The mean expected heterozygosity (H_e) of all populations was 0.618. The proportion of genetic differentiation among populations accounted for 19.6% of the whole diversity, and the gene flow between populations (N_m) was 1.02. The result of UPGMA clustering indicated that the populations were congregated according to their geographic distances instead of tree species.
