Abstract:

Genetic variation on rooting ability of stem cutting and 3～5 years old growth of 12 Larix kaempferi×L. olgensis hybrid families，including polycrossed and fullsib families，and 4 corresponding openpollinated female parent families were analysed and contribution of parents on the variation among hybrid families were studied. Result indicated that there were very significant differences in both rooting traits and growth traits among hybrid families, which demonstrated that maternal and paternal effects were obvious and these traits had great potential for hybrid family selection. The phenotypic and genotypic correlations within rooting traits, and within growth traits of families were highly significant, while the correlation between rooting traits and growth traits was insignificant. This results showed that it was highly promising to pick out the right families with better performance in fast growth and high rooting quality. According to the subordinate function values, 4 fast growing and high rooting families were selected, whose mean height, basal diameter and 3 year survival rate after afforestation were higher than the average of 4 open pollinated families by 24.7%，28.9% and 55.6% respectively, while the rooting ability remained the same.

Key words: Larix kaempferi×L. olgensis hybridization, heterosis, rooting variation, growth variation, multiple selection