Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "Mating system in a clonal Douglas fir (Pseudotsuga menziesii (Mirb) Franco) seed orchard. II. Effective pollen dispersal. | 213 Ann Sci For 1995 52 213-222 Elsevier INRA Original article Mating system in a clonal Douglas fir Pseudotsuga menziesii Mirb Franco seed orchard. II. Effective pollen dispersal D Prat Laboratoire INRA-ENGREF de sciences forestleres 14 rue Girardet 54042 Nancy cedex France Received 15 February 1994 accepted 4 July 1994 Summary Genetic variation of effective pollen received by individual ramets in a Douglas fir clonal seed orchard was not representative of the genetic variation of this clonal seed orchard. This deviation was not due to selfing rate. Effective pollen dispersal might be responsible for this deviation. It was then assessed around 3 individual ramets by comparing genotypes of effective pollen with those of pollinator and surrounding trees located in a circle or in an ellipse focused on the receptor tree. The best prediction of genetic diversity of effective pollen was obtained considering a maximum pollination distance of about 20-30 m and an elliptical pollen dispersal. Effective pollen dispersal took place preferentially along rows of trees and probably depended on the wind. As the flowering period was short and particularly synchronous in the year of seed collection reproductive phenology probably did not favour some peculiar crosses. Matings between a few neighbour trees was probably the major cause of the homozygosity level in seed crop. isozyme mating system pollen dispersal Pseudotsuga menziesii Douglas fir surrounding trees Resume Regime de reproduction dans un verger à graines de Douglas Pseudotsuga men-ziesii Mirb Franco. II. Dispersion du pollen. La diversité génétique du pollen regu par des ramets individuals d un verger clonal à graines de Douglas n etait pas representative de la diversité géné-tique de ce verger. Ceci ne résultait pas du taux d autofecondation comme I ont montré des etudes anté-rieures. Une dispersion réduite du pollen pouvait en être la cause. Aussi la dissemination du pollen a été étudiée autour de 3 ramets .
