Abstract:

Seed production, interval yielding and bearing habits of different clones were analysed systematically based on the data from 1973～1995 in the seed orchard of L. Kaempferi on Dagujia Forest Farm, Liaoning Province. The Primary seed orchard with 158 clones was established in 1965 coving an area of 14.7 hectares. The mother trees are taller due to failure to keep the height under well control. Seed collection started in 1973 though a few of trees flowered and beared in 1971. Up to the year of 1995, 1935.58kg seed was harvested in total. Seed production was quiet low within 16 years since the orchard had been established, and the maximum yield was no more than 2.1kg/hm²·a. Seed yield increased to 25.0kg/hm² when the orchard was 25 years old, yet productivity still remained in low level (5.81kg/hm²·a) during the orchard was 22～26-year-old. Interval yielding was obviously in the seed orchard of L. Kaempferi and aboundant year occurred 5～6 year interval. There were significant to extremly significant positive correlation between seed yield and age of orchard, number of producing trees, but significant negative corretion was found between seed qulity(Percentage of empty seeds) and age of orchard, number of producing tree, seed production. Significant to extremely significant positive correlations were also found between crown diameter of mother trees and cone production in aboundant year, total cones produced in recently three years, but there was not any obvious correlation between the height of mother trees and cone yielded. Cone production differed obviously for different clones. Rank correlation analysis indicated that there was significant correlation between cone yield at the early and final stage. It is possible that the early selection of high-yield clones of L.Kaempferi can be conducted according to the cone yield in the first three years, and five years later, final selection could be made according to cone yield in the first eight years. The main factors to lead low productivity of the Jepanese Larch Orchard are extremely difference of seed production on-year and off year, a long interval period between on-years, and less high-yield clones.

Key words: Seed orchard of L.kaempferi, Seed yield, Productivity, Fruiting laws, Jurenile-mature correlation of seed production