The Study On The Breeding Of New Clones Of Populus Davidiana×P.tremuloides

This research project is the first large scale and systematic to carry through breeding about P. davidiana×P tremuloides. The advanced international breeding procedure "B-S-C-S" was adopted to carry out geographic distant crossing, and the new good clones were selected. Improving the genetics character of P. Davidiana has more important value. By the research on microbody propagative techniques, the optimized system that was suitable to clone breeding of P. Davidiana×P tremuloides was built, which could resolve the difficulties of clone breeding and low propagative rate of Populus Davidiana. The result of the thesis is as follows.The firstly, by mean of crossing breeding and another realitive techniques, the eight good families,the ten good single trees and the four choiceness hybrid clone were selected, which were Id42-1, Gd42-1, Ca42-1, Gh32-2. The hybrid Id42-1, Gd42-1 were the triploid .Those four were growing fast, and the tree height of 7 years old over 9.5m to 10.5m, DBH 8.7cm to 10.9 cm, volume 0.0255m3 to 0.0448 m3; and the new clones with high resistance and no freeze injury have very good propagative potential.The secondly, the culture medium WM was feasible beginning culture medium; The improved culture medium WM was fit for continuous passage multiplication.The multiplication coefficient was 11 ~ 15;During the tissue culture of P. davidiana X P tremuloides,both cane sugar and agar had influences on vitrification.The best cane sugar and agar combination was cane sugar 7g/l,agar 30g/l. High temperature,plastic film of bad ventilate nature and insufficient light intensity accelerated vitrification seedlings producing remarkably;The improved culture medium WM and 1/2MS were fit for rooting culture of hybrid clone,the rooting rate was up to 92.8%~93.3%.By means of improving the tissue culture programme,the wand cuttage was used into tissue culture. These techniques overcame the difficult problems of asexual propagation of P. Davidiana ×P tremuloides,curtailing the breeding period, optimizing the propagation programme.The thirdly, the SSR molecular marker was used to analysis genetics biodiversity of 3 type with Populus Davidiana with 5 special primers, through Shannon index and Nei's index guess genetics diversity, we can make sure that the Populus Davidiana had the highest genetics diversity, and the second was P.davidiana×P. tremuloides(Xiaoxinganling), and the least was P. davidiana ×P tremuloides (Zhang guangcai ling). Using the genetics distance matrix analysis, and the result was that: on the basis of genetics distance, the each hybrid of P.davidiana×P. tremuloides was congregated as one sort at first, then with the P.davidiana as one sort.