Comparative study on plant traits between sexual and asexual reproduction for Pinus tabuliformis.

In this paper, grafted clones and open pollinated halfsib families with plus trees and random selected grafted individuals and seed seedlings of Pinus tabuliformis were used to study trait variation between sexual and asexual reproduction in trunk growing, crown structure, wood properties and cone production. And correlation analyses were conducted among traits in grafted individuals and seed seedlings. Results showed that parameters of tree trunks and wood density were measured relatively consistent within grafted clones and among different halfsib families. Other observed traits demonstrated no significant differences between the halfsib families and the grafted clones of plus trees, but the average value of trunk growth and needle length in the grafted clones were higher than that of halfsib family. Basic density of juvenile wood as well as mature wood was relatively consistent in grafted clones, while it was quite different in halfsib families; randomly selected grafted individuals and seed seedlings had significant difference in traits of crown structure and cone yield，but no significant in lateral branch and wood properties. Correlation coefficients of diameter at breast height with branch angle，comparative length of the branch (rate of branch wide to height of tree) and comparative wide of the branch (rate of branch wide to diameter at breast height) with index of early and later wood were positive and negative contrary，correlations between average wide of the early and late wood and wood density reached significant level. Traits among height growth, strobilus production, wood density，early and later wood were relatively independent. Results of this paper provide the theoretical basis for cloning selection, clonal afforestation and seed orchard establishment of P. tabuliformis in the future.