Investigation on the poplar's characteristics clones in experimental nurseries in Zanjan province

The purpose of this research was to select the suitable poplar clones at seedling stage among 65 clones in a period of five years. The following parameters were investigated: Height and growth diameters, percentage of survival, percentage of cutting spruted in different time of planting, the effects of cutting at the base of shoots on the growth of side tillers, shoot growth rate at 1/1 (one year root and one year shoot), uniformity of seedling growth and major pests and diseases and the rate of sensitivity of each clones. The results demonstrate that at the end of growth period, percentage of survival for Populus alba was lower than the other species. This was due to decrease of root forming and low percentage sprouting of cuttings in P. alba. Populus alba and section Tacamahaca were less sensitive to adverse environmental conditions (specially moisture) than the other species. The study indicated that P. deltoides species had the highest growth rate and Populus alba had the least growth when "Cutting at the base of the shoot" technique was applied. Among different group of Poplars studied, section Tacamahaca was more susceptible to pests and diseases (specially wood bore insects) than the other groups, and P. alba from leuce section was among the group having the highest resistance to wood borer attack. Finally, it should be stated that among the clone of each group, there were more differences than what we have expected.