Abstract:

The test result from slash pine experimental forest of 43 half-sib family's planted in 1981 shows that there are significant difference in height, DBH(diameter at breast height), volume, stemform, branch diameter and timber density among different families, which possesses some heritability and the significant family effect of the tracheid length was not found; the growth and timber characteristics are controlled to certain extend by genetic factors. There are positive correlation among height, DBH and volume while the correlation among timber density, tracheid length and volume growth isn't obvious. Therefore, with the help of constraint and free selection indexes, and according to different demand between pulpwood and building timber, combination selection of growth, quality and timber properties,was carried out. Four families, No. Ⅳ-47^#,2.46^#,0.609^#and 0.464^#,are the best for pulp wood, and three families of NO. 0.187^#,0.464^# and 0.609^# are suitable for building timber.

Key words: Slash pine, Half-sib family, Genetic variation, Growth timber quality and form, Combination selection