Genetic variation of height growth rhythm between clones of Larix kaempferi x L-gmelini based on logistic models

Fifty-three larch interspecific hybrid clones (Larix kaempferi x L. gmelini) and their parent clones were used for growth curve analysis of height variations. The growth curves of the 55 clones were 'S'-shaped and 36 exhibited similar curves as the male parent. The coefficients of the logistic models were higher than 0.943, indicating that our results were effective in the simulation of the growth curves. ANOVA analysis showed significant differences in height of different clones (P < 0.01). Average date of maximum height growth was Day 173, and average duration of rapid growth lasted for 50 days. Annual average increase in height was 9.7 cm d(-1) and daily average increase was 0.2 cm. The ratio of GR to the total annual increase in height ranged from 51.2 to 68.8%, with the average being 59.8%. There was a positive correlation between k values and plant heights which benefited from the evaluation of early plant height. There was also a positive correlation between GR (growth stage), GD (plant height) and annual increase in height. These results are informative to the evaluation of the elite clone selection and provide a theoretical basis for breeding and management.