Study on Selection and Breeding for Multifunction of New Variety of Populus tomentosa

13 year poplar clonal stand in the 3 sites of Beijing, Hebei, Henan are observed and surveyed for properties of heights, DBH, timber density, timber length.Remarkable variance is shown among the observed traits.The genetic stability, growth adaptability, stem straightness coefficient, form shape coefficient, anti-blight index exhibited certain difference.The interactive variation of site×clone is extremely remarkable.The observed clones can be categorized into 3 types as "general adaptive", "high yielding" and "low yielding".The volume increment, timber density, stem straightness coefficient, form shape coefficient and anti blight index and repeatability are estimated as 0.580, 0.536, 0.390, 0.411 and 0.500 respectively .The economical trait weight is 0.35, 0.25, 0.10, 0.10 and 0.20 respectively.A multi functional clonal selective index is developed, the breeding gain of the clones which exhibits 15% more than that of CK can be selected as excellent clones.Respectively 8, 7 and 6 excellent clones are selected for the 3 sites mentioned above and the average comprehensive gain is 23.9%, 24.9% and 21.0% respectively.In respect to clones No.37, 351, 9832 and 1012 which are commonly selected as excellent clones, the average comprehensive gain can be as high as 25.1%.The clones selected are all of male sex, the greening effect can be enhanced greatly.