Genetic variation among <i>Larix kaempferi</i> (Lamb.) Carrière plantations in South Korea based on microsatellite markers: implications for seed productivity

Recently, Larix kaempferi has become a major timber resource in South Korea. However, seed production for afforestation remains insufficient to meet the high demand for wood. This study analyzed the genetic variation in L. kaempferi plantations in South Korea to explore whether poor seed production in plantations was due to reduced genetic diversity during their introduction as seeds from the country of origin, Japan. The genetic diversity parameters of 10 L. kaempferi plantations in South Korea were analyzed using seven microsatellite markers. The averages number of observed alleles (NA) was 8.129. The average observed and expected heterozygosity were 0.662 and 0.706, respectively. The results suggested that the poor seed production and germination rates were not due to genetic diversity limitations during the introduction process compared with native populations on Mt. Fuji in Japan. The mean of genetic differentiation (FST) was 0.027. Analysis of molecular variance (AMOVA) indicated that 8% of the total genetic variance was differentiation among 10 plantations. Genetic variation due to differentiation among the 10 plantations was slightly higher than that in the native populations. The 10 plantations were grouped into two clusters in principal coordinates analysis (PCoA) and unweighted pair group method based on arithmetic average (UPGMA). We suggest that seed collecting from considering genetic variation of plantations. Jeongseon, Yangpyeong, Gangneung, and Hoengseong are recommended as priority sites for seed collection, given their superior genetic diversity within each cluster. It will be useful to collect seed genetically diverse for seedling and establishing seed orchard.