Estimation of Genetic Diversity between and within Biparental Clones and Full-Sib Families of the Chinese Pine Using SSR Markers

Abstract

Quantifying the genetic diversity present in plant populations is crucial for the success of selection of elite plants and breeding programs. The population structure and partition of genetic variance within and between plant populations allows inferences about the distribution and extent of variation available in plant breeding populations. The Chinese pine (Pinus tabuliformis Carriere) is a native species that is ecologically and economically important to Northern China. Studying the genetic variation and partition of P. tabuliformis will be invaluable for its efficient utilization. In this study, we selected 21 pairs of SSR primers to estimate the genetic diversity of 35 clones from four populations and 216 progenies from 22 full-sib families of P. tabuliformis. Our results showed that P. tabuliformis was a typical outcrossing plant (FIS = −0.053/−0.165) containing moderately high genetic diversity (He = 0.542/0.605) both for the clone populations and the progenies produced by the clone crosses via controlled pollination. The genetic differentiation between the clones (FST = 0.076) was lower than that between the full-sib progenies (FST = 0.155). Such diverse FST may be promoted by different gene flows (Nm = 3.881/1.546) due to distinct pollination patterns. The clustering methods showed a lack of significant division of the clone populations, with a similar genetic admixture found for each of the clones. However, two groups were found between the full-sib families with genetic admixture between them. The analysis of molecular variance (AMOVA) showed that the most plentiful genetic variability exists between the cloned individuals (98%) as well as within the full-sib progenies (89%). Such distribution of genetic variation suggests rich internal variance and thus it is feasible to select the elite plants within each population or family. These results provide genetic materials and theoretical guidance for the selection and breeding of the Chinese pine.