Genetic diversity, population structure and a core collection establishment of Pinus yunnanensis using microsatellite markers

Pinus yunnanensis Franch. is an economically and ecologically important pine endemic to southwest China. A large number of low-quality and low-efficiency individuals have appeared in P. yunnanensis forests due to climate change, environmental stress, and human overexploitation. There is a lack of comprehensive information about the genetic diversity, population structure and a core germplasm collection establishment with individuals taken across its natural range. Understanding the important information will be invaluable for germplasm efficient conservation and utilization. A total of 287 individuals from 10 populations across its range were analyzed using 17 polymorphic microsatellite markers. The research revealed P. yunnanensis was a typical outcrossing plant (F-is = - 0.1), maintaining moderately high genetic diversity (H-e = 0.540). The continuous distribution and wind-dispersal traits of two-sacs pollen and winged seeds may have promoted gene flow (N-m = 12.71) and lessened genetic differentiation between populations (F-st = 0.023). There was a lack of significant isolation by distance (P = 0.07). Geographical and ecological isolation following the uplift of the southeastern margin of the Tibetan Plateau may have contributed to the formation of three discrete groups (K = 3). A core collection of 72 individuals (25% of the whole collection) was established, of which genetic diversity parameters showed no-significance from the whole collection. In situ conservation of the three populations (XC, CY, and XP) showing distinct genetic diversity was recommended, and ex situ conservation for individuals with private alleles. The core collection was recommended as a possible germplasm resource for tree breeding and improvement.