Growth characters and number of strobili in clonal seed orchards of Pinus sylvestris

Observations were made on six grafts for each of 25 clones in three Scots pine (Pinus sylvestris) seed orchards in Turkey. The characters studied were number of female and male strobili, height below and above the longest branch, total height; diameter at base and breast height, crown diameter, and number of branches. Variation, broad-sense heritability (H ²) and correlations between characters were estimated. Variation among clones was lower than among grafts within clone for all characters. The genetic variation for number of strobili varied between 0 and 17% of total variation, while that for growth characters values varied between 2 and 13%. The number of female strobili appeared more variable among trees than the number of male strobili. H ² was not consistently high for any character or seed orchard. The number of strobili increased with the size of the tree, but not dramatically. Correlations between measures of tree size (both on clone level and individual graft level) and the number of strobili were in the magnitude r ≈ 0.3. Diameter at breast height seems a reasonable predictor for number of strobili.