Variation among clones and ortet-ramet relationship in grafted Scots pine (Pinus sylvestris L.)

摘要

In order to study the relationship between ortets and ramets (grafts) growing in the same environment or at widely different localities, clone trials were established with 20 and 45 clones, respectively, at two localities in central Sweden. The ortets selected were plus trees or trees with poor to normal growth and quality, and of considerably varying age. The characteristics studied in 1-3 years were stem dimensions; number of branches; branch length, diameter and angle; stem straightness; and cone yield. The variation among clones was studied and the components of variance estimated. The main source of variation were the site differences within each locality. The variation between clones was pronounced in most traits, particularly in cone yield, and increased with age. The repeatability in each clone was good in one test field but poor in the other. Correlations among various clone characteristics, e.g. cone production and graft habitus, have an impact on the gain to be obtained in a seed orchard. The relationships beween ortets and ramets varied but were not as close as those reported from other similar investigations with the exception of those concerning branch angles.