Gene diversity and mating system of Pinus tabuliformis in finite population seed orchard.

A total of 63 clone parents (there was repeat in the clonal parents) and 320 open-pollination progenies were identified by 10 polymorphic SSR loci from three configuration areas of a Pinus tabuliformis seed orchard. We chose the parent and progeny population of ninth configuration area as for our study on the relationship between fixed configuration and mating system. The results showed there was a high genetic diversity in the seed orchard, progeny population had all alleles detected in parent population, and even had some new alleles absent in parent population. In the analysis of the mating system at 80% confidence level, the exchange rate of the configuration area had reached 100%, indicating that most of the mating system of P. tabuliformis seed orchard was based on outcrossing under the fixed configuration. The average neighbor mating rate (7.07 m) was 21.90%; the rate within and beyond 40 m was 71.43% and 6.67%, respectively, indicating that the distribution of pollen in the fixed configuration was relatively uniform, and the range of pollen dispersal was widespread. As to the study of gene exchange between the configuration areas, we found that each of configuration area was affected by pollen from the other two configuration areas to different degrees, indicating that the gene exchange between each configuration area was relatively sufficient. In addition, we found the rate of contamination by pollen outside the seed orchard was as high as 11.88%.