Genetic variation in wood specific gravity of half-sib families of Pinus nigra subsp. pallasiana tested at the juvenile stage: Implications for early selection

Seeds from 7 populations (total of 281 half-sib families, progeny test) and 35 seed stands (provenance test) representing natural range of Anatolian black pine (Pinus nigra subsp. pallasiana) were sown in a forest nursery in Ankara in 1990 and raised until age 3. Stem wood specific gravity (WSG) of all seedlings was determined at age of 3. The results of this study indicated that WSG did not vary significantly neither among the 7 populations (ranging from 0.41 to 0.42) nor among 35 seed stands (ranging from 0.37 to 0.46). Differences between half sib families for WSG were, however, statistically significant. Estimated family heritablity was moderately high (0.38). Genetic correlations between seedling growth traits and WSG were low, but consistently negative. The families with better height and diameter growth had lower WSG values. Also families with late budset and budburst dates in 1991 had lower WSG values. Seedlings originating from northern latitudes had lower WSG than those from southern latitudes. From the results of the study, it seems that early selection of families for WSG (indirect selection for WSG at mature age) would be possible and substantial genetic gain in WSG could be achieved if the selection based on a multi-trait index selection by giving appropriate weights to WSG and other traits. Further implications of early selection for WSG in Anatolian black pine are also discussed in the paper.