Genetic Variation and Initial Selection of Clones from Hybrid between Populus deltoides Marsh.×P.cathayana Rehd.

The controlled hybridization between a female Popupus deltoides Marsh.'55/65' and 5 provenances （10 individuals each provenances） of the male P.cathayana produced the hybridization system with multile-level variations for breeding with F1 clones.For 5 years after planted in plantation,115 clones of 25 families were experimented.The growth traits,including height,diameter at breast height and volume,of F1 hybrid clones and their different resistance ability to Dothiorella gregaria （poplar canker） were analyzed.The analysis of variance showed that among F1 hybrid clones,the significant differences of 5-year-old growth traits existed among clones of male-parent P.cathayana from 5 provenances,among families within 5 male-parent provenances and among clones within families.The significant difference of 5-year-old growth among F1 clones showed that the selection potential was greater among F1 clones.On base of growth traits and resistance to D. gregaria,36 super clones were selected and used for multi-traits selection in future.