A Study of Variation of Growing Traits of Liriodendron and Its Excellent Provenance Selection

In this paper,Liriodendron provenance forest at the age of twenty-two in Qionglai National Forest Farm in Sichuan province was taken as the research object,the main growth traits such as tree height (H), diameter at breast height (DBH),volume (V),height under branch(HB) and crown width(CW) were determined in order to analyze the genetic variation and conduct the selection of its provenance. The results showed that there were statistically significant difference in H,DBH,and V among different provenances,while there were significant difference in HB,and CW. The average H,average DBH,average V, average CW and average HB of 9 provenances were 12.44 m,20.20 cm,0.2182 m³,3.18 m and 8.35 m respectively. The elevation level had a significant influence on the DBH growth of Liriodendron. The hereditabilities of tree height, DBH, volume of tree, CW and HB were 0.856, 0.847, 0.806, 0.576 and 0.547,which indicated that the growth traits were strongly controlled by genetic factors. Three superior provenances Liping Guizhou,Xuyong Sichuan and America A, were selected by synthetic evaluation. The selected provenances' genetic increments of DBH, H and stem volume were 19.56%, 6.60% and 35.36% respectively. Six superior individuals were selected out by comprehensive appraisal,whose average DBH,H and stem volume were 30.4 cm,15.17 m and 0.5230 m³ respectively, and exceeded the population means of 22.09%,14.47% and 66.63% respectively. This study provided the material conditions and theoretical basis for the cultivation and popularization of Liriodendron in Sichuan region.