Abstract
For 17 Japanese cedar (Cryptomeria japonica D. Don) clones planted in a progeny test plantation, we investigated the male flower setting four times during 17 years in 26 to 42-years-old trees, particularly examining mast years. The 17 clones were 15 plus trees and 2 local varieties. As a result, the clones with high male flower setting as of 26 years old showed the tendency for male flower setting to be high, to 42-years-old. The clones with low male flower setting showed a low tendency to 42-years-old. Therefore, estimation of the male flower setting of Japanese cedar clones became clear as of 26 years old. Moreover, results suggest that the change of male flower setting accompanying aging of the 17 investigated clones is not uniform and that male flower setting varies with heredity. In addition, as of 42-years-old, the clones to which the male flower setting index became smaller than the clones selected as a Japan cedar with little pollen existed in the clones expected to be stable also by aging while male flower setting has been low, therefore, it was thought that clones with little pollen might be chosen more.
