Abstract: [Objective] The objective of this study was to reveal the genetic variation in parents and progenies and the effects of mating patterns on genetic diversity of the progenies. Furthermore, it also provides a scientific basis for the genetic management of the seed orchard of Schima superba.[Method] The study site is located in Lanxi nursery, Zhejiang province. A total of 44 parent trees and 328 open-pollinated progenies from 11 clones in the seed orchard of S. superba were analyzed using 13 polymorphic SSR loci.[Result] We detected 5-9 and 5-11 alleles (N_a) respectively in parent and progeny population, with an average of 6.286 and 7.786, respectively. The effective number of alleles (N_e) was 3.097 and 3.751 in parent and progeny population, respectively. The N_a and N_e in progeny population was 1.500 and 0.654 larger than those in the parent population, respectively. The progeny population had all alleles detected in maternal population, and one to five alleles not detected in the maternal population. The level of genetic diversity of the progeny population (H_e=0.600) was slightly smaller than that of the parent population (H_e=0.632). The observed heterozygosity (H_o) was higher in the progenies than in the parents, but not significantly different. The results indicated that the genetic uniformity and the proportion of observed heterozygosity in the progenies displayed an increase compared to the parents, but not at a significant level. The Shannon's information index (I) and Nei's genetic diversity (h) was 1.152 and 0.611 in progeny population, respectively. The value of I and h were all basically consistent with the parent population. There was an obvious heterozygosis excess in progeny population (F=-0.143). Results from multilocus mating system analysis revealed that the multilocus outcrossing rate in the seed orchard was 1.000 and the single-locus outcrossing rate (t_s) was 0.939, and there was no significant inbreeding between parents (t_m-t_s=0.061). A slight biparental inbreeding was detected in this seed orchard. We found a small number of effective pollen donors (N_ep=2.3). The D-value between multilocus correlation of paternity and singlelocus correlation of paternity (r_p(s)-r_p(m)) was 0.012>0, indicating that only few pollen donors were close relative relationship. The difference of correlation of paternity (r_p) between the 11 families was from 0.210 to 0.762. And the number of valid pollen donor was 1.3-4.8, showed that the degree of correlation was inconsistent among paternal parents, the highest was clone 31, and the lowest was clone 48. However, outcrossing rate was not significantly different among parents (t_m:0.092-1.073), and a few selfing events were detected in some families (No.31:t_m-t_s=0.107;No.9:t_m-t_s=0.117).[Conclusion] There was a high outcrossing rate, and a lower biparental inbreeding in this seed orchard. Gene exchange among clones was relatively sufficient, and genetic diversity in the progenies was kept as high as in the parents.

Key words: Schima superba, seed orchard, SSR, genetic diversity, outcrossing rate