1. Key Laboratory of Tree Breeding and CultivationState Forestry Administration Research Institute of Forestry Chinese Academy of Forestry. Beijing 100091 China; 2. Forestry and Horticulture College of Henan Agricuh ure University, Zhengzhou 450002. China; 3. Dagujia Forest Farm Liaoning Province. Qingyuan 113305, China
In order to investigate the difference of wood tissue proportion of Japanese larch clone and to provide more theoretical instructions for improving wood properties genetic ot Japanese larch, genetic variations of wood tissue proportion of 10 Japanese larch clones at 10 years were investigated. The result revealed that tissue proportion had a significant difference among clones. The proportion of resin showed a highly significant difference among dif ferent rings. The prophase variation curve of proportion of tracheid appeared as"Trapezoid" and the latter variation curve appeared as "V"from pith to outward. The proportion of wood ray declined rapidly in the beginning while declined fluctuatly or rose until the second age ring from pith to outward. The proportion of resin canals declined slowly in the beginning, then it rose rapidly to maximum, but declined rapidly again afterwards. The wood ray pro portion was well fitted by hyperbola equation and power equation(R2>0.7). The proportion of resin canals was well fitted by exponential equation (R2=0. 609). The proportion of tra cheid was well fitted by cubic polynomial equation(Re=0. 845). The relationship between wood tissue proportion and growth and form was not significant. The relationship between the proportion of wood ray, the proportion of resin and the proportion of tracheid was significant. The broad sense repeatability estimates of clones were 0. 571,0. 453 and 0. 607,indicaring the proportion of wood ray, the proportion of resin and the proportion of traeheid were under middle and strong genetic control. The average genetic gains were 16.70% and 207. 72% for the proportion of wood ray and the proportion of resin if 20% of the best clones was selected.