Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Flowering and cone production variability and its effect on parental balance in a Scots pine clonal seed orchard. | Ann Sci For 1997 54 129-144 Elsevier INRA 129 Original article Flowering and cone production variability and its effect on parental balance in a Scots pine clonal seed orchard JBurczyk1 w Chalupka2 1 Pedagogical University Department of Biology and Environment Protection ul Chodkiewicza 30 85-064 Bydgoszcz. I 2Polish Academy of Sciences Institute of Dendrology 62-035 Kórnik Poland Received 26 June 1995 accepted 19 February 1996 Summary - Clonal variation in flowering characteristics and cone production was investigated in a Scots pine Pinus sylvestris L clonal seed orchard consisting of 32 clones. At the time of observations the orchard was 17-19 years old. It was found that on average within a clone female flowers were receptive about 1 day before the beginning of pollen shedding and there was a significant correlation between the ranks of clones according to their onset of flowering in 2 consecutive years. Male and female flowering periods were synchronized among the majority of clones and the index of phonological overlap was over . Significant variations among clones were found for male and female cone production as well as for some selected pollen-related characteristics. On average individual clones in the orchard produced in total from to kg of pollen and from 900 to 6500 cones a year. It was found that 25 and 50 of clones produced 46 and 72 of pollen respectively. Analogous numbers for cone production were 35 and 63 . Some patterns of sexual asymmetry among clones were detected however genetic correlations between pollen and cone productions were positive. Effective population sizes were generally high but the estimate was lower for pollen than for cone production . The expected outcrossing rate based on effective population size calculated using both male and female contribution and background pollination was high . The efficiency of the orchard and its potential use for reforestation purposes is discussed. Pinus sylvestris I .
