Investigation on growth and yield of ten half-sib hybrid Poplar clones in Karadj

The research project consisted of two phases. At first phase, the required seedlings were propagated from seeds produced naturally on clonal material stock of P.deltoides 69.55, which is a fast growing clone for Guilan and Mazandaran provinces of Iran. Among the propagated seedlings, 254 individuals were selected and planted at a research nursery. After three years study and evaluation program, 10 samples from the nursery were selected for further trials and 10 numbers were allocated for the samples (P.d. 63.1-P.d. 63.10). Height and diameter growth and resistance to pests characteristics were used to select the samples. At the second phase, final investigation and selection of more productive clones in comparison to the material stock, was made at experimental Stations of Alborz (Karadj city), Guilan, Kermanshah, Chaharmahal va Bakhtiary and Kurdistan provinces. In 1998 cuttings were made as more as possible from clones of 63.1 to 63.10 and then planted at Karadj nursery. At the end of 1999, 75 rooted cuttings were selected from each clone (similar height) and planted under the statistical design of randomized complete blocks, with three replications, 4m×4m spacing. Besides, cuttings of P.deltides 69.55 were planted as control treatment. The annual measurements consisted of determination of sexuality, height and diameter growth, annual increment and climate records. The statistical analysis was made, using SAS software. Results showed that among the 10 clones, four clones were male, five clones were female, one clone did not produce flower yet. P.deltoides 63.10 was the most productive clone (23.9 m3/ha/y) whereas the control clone (P.deltoides 69.55) produced about 17.4 m³/ha/y wood.