An examination on the site–family interaction of tree height of open-pollinated families of hinoki (Chamaecyparis obtusa) plus trees in the Kansai Forest tree breeding region

摘要

Stability analyses to evaluate site–family interaction for tree height at 15 years old were conducted in trials of open-pollinated families of hinoki (Chamaecyparis obtusa Endl.) plus trees established in the Honshu and Shikoku area of the Kansai Forest tree breeding region, Japan. The Honshu area included 103 sites (226 families), and the Shikoku area included 27 sites (62 families). Analyses of variance indicated that the interaction between site and family was not significant in the Honshu area, whereas in the Shikoku area the interaction was significant. The stability analyses regressed the family–site means against site means. The linear regression analysis was carried out using the data for 164 families that were tested at five or more test sites from the 130 test sites. Approximately 93% of families had values of linear regression coefficient that were not significantly different from unity. These results suggest that almost every open-pollinated family of hinoki plus trees have average stability and are equally well adapted to good and poor sites. The differences in the reaction of a family to site productivity are not the main causes of the interaction.