Growth and Wood Traits Variation and Selection of Superior Clones of eight-year-old Liriodendron sino-americanum

Objective Liriodendron sino-americanum P.C.Yieh ex Shang et Z.R.Wang is a new-generation preferable tree species in ecological reforestation, ornamental plantation, and timber production. In order to explore the genetic variation of growth and timber wood density, as well as to select excellent clones with best growth performance and wood properties for breeding material.

Method Overall 120 eight-year-old L. sino-americanum clones, which were planted in Zhangping Wuyi State-owned Forest Farm, were used to analyze the level of genetic variation of tree height (H), diameter at breast height (D), crown width (CW), individual tree volume (V) and wood basic density (WD).The ANOVA method was used to detect the variation among clones on growth and wood traits. Phenotypic and genotypic correlation between traits were analyzed. Comprehensive selection index (I) was performed to select superior clones.

Result the variations among clones on growth and wood traits were significant (p<0.05) or extremely significant (p<0.01). Similar trend of changes (V>D>CW>H>WD) were found in genetic variation coefficient (V=25.62%, D=10.53%, CW=10.31%, H=8.94%, and WD=5.83%) and clonal repeatability (V=0.709, D=0.643, CW=0.640, H=0.602 and WD=0.552). No significant correlations were detected between growth and wood traits. Fifteen clones were identified as superior clones, with an average selection rate of 12.40% and an average selection intensity of 1.73. These clones demonstrated significant average realized gains in H at 22.25%, D at 29.45%, CW at 28.64%, V at 74.14%, and WD at 11.04%, compared to the mean values of all clones

Conclusion The tested clones exhibit significant variation and strong selection potential. Each trait evaluated is predominantly governed by genetic factors and demonstrates good genetic stability. The growth traits and basic wood density show relative independence in their genetic correlations. The fifteen selected excellent clones possess high genetic gain and can be utilized as materials for future breeding and propagation.