[Objective]P.deltoides cl.'Danhong'×P.nigra cl.'44'was used to establish an efficient and stable regeneration tissue culture system and genetic transformation system for black poplars(P.deltoids×P.nigra),based on the roots as explants.[Method]The 0.5～1.0 cm root segments from clone'44'seed-lings were used to induce adventitious buds.The effects of different hormone ratios on the induction and rooting of adventitious buds were investigated and the critical screening concentration of phosphine oxal-ate for genetic transformation of the root segments was explored.Agrobacterium-mediated method was employed to introduce foreign genes into the clone'44'root cells,and the transformed seedlings were identified by β-glucuronidase staining.[Result]The optimal medium for bud differentiation of clone'44'was WPM+20 g·L-1 sucrose+7.8 g·L-1 agar+0.25 mg·L-1 6-BA+0.05 mg·L-1 NAA,and the differenti-ation rate was 86.67%.The optimal medium for seedling rooting was WPM+0.075 mg·L-1 NAA+7 g·L-1 agar+0.1 g·L-1 AC,and the rooting rate was 75.00%.The optimal genetic transformation screening con-centration for glyphosate resistance in roots was determined to be 0.8 mg·L-1 through a gradient test.Exo-genous genes were introduced into roots by Agrobacterium-mediated method,and the specific PCR primers were designed for identification of the transgenic lines.Nine transgenic plants were obtained from 31 explants,with a transformation efficiency of 29.0%.[Conclusion]The efficient regeneration and genetic transformation system for clone'44'has been established,which provides a technical support for trans-formation of black poplar species and adding excellent traits through genetic transformation to clone'44'in particular.
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