About the heritability influence to the growth performance in Scots pine (Pinus sylvestris L.) progeny trials

Abstract

About the heritability influence to the growth performance in Scots pine ([Pinus sylvestris] L.) progeny trials

The aim of the present paper is to estimate heritability of tree height and DBH of the Scots pine experimental plantation in Järvselja Training and Experimental Forest District, using data of the 39- and 40-year-old progeny trials.

In 1965 and 1966 cones were collected for the progeny trial from 12 plus trees and 30 single trees (not recorded in the plus tree register) from different regions in Estonia. Spatial and dendrometric data of selected mother trees are presented in Tables 1 and 2. In 1967 and 1968 total of 5.65 ha were planted with two-year old seedlings by 1.5×1.25 m. In 2007 all trees of progeny trial were callipered and nine sample trees were measured for height on each plot. Our progeny data set consists of 3707 DBH and 513 height measurements.

We present the statistical analysis of a set of progeny tree measurements, carried out with the SAS package, Release 9.1 (SAS Institute Inc. 2004). We exploited the SAS procedure MIXED experimenting with the Residual Maximum Likelihood method (REML). Heritability of the DBH is very low but still statistically significant as seen from Table 3. The heritability of tree height is high, which has also been noted in our previous study (Kurm [et al.], 2000). We found a significant positive relationship (R[2] = 0.25) between age of mother tree and progeny height. Also, average height of plus tree progeny was slightly greater than average height of single trees. According to Tukey HSD test for multiple comparison of means on progeny height data, we distinguished two groups of regions: (1) single tree progenies from regions close to sea and (2) tree progenies from South-East and North-East Estonia.