Cross And F1Generation Seedlings Test Of Local Populus Of Sichuan

To make full use of the rich germplasm resources of Sichuan local poplars and breed some new species which are more suitable for Sichuan ecological environment, this thesis studied the cross between local poplars, local poplars and P. deltoids, and the test of genetic research of the F1hybrid offspring, discussed application of soil and water culture devices, the crossability of hybridization, the variability of the offspring and the heritability of the important characters. The result can offer the theoretical guide to for future local poplar hybridization and parents selection, and laying the material foundation to the selection of excellent subsequent hybrid breeding clones. The main research conclusions are as follows:(1)219combinations were carried out and69combinations of them produced seeds. According to sowing and isolated culture of immature embryo,31combinations of them were germinated, which including21poplar species. This indicated that all these21combinations has crossability and can produce stable genetic hybrids.(2) The germination rate and survival rate of the seeds from the cross combinations of P. cathayana (10-25)×P. deltoids (10-19),"Erlang poplar"(10-12)×P. cathayana (10-1),"Erlang poplar"(10-12)×P. deltoids (10-19), P. szechuanica (10-22)×P. deltoids (10-19) and P. trinervis (10-8)×P. deltoids (10-19) were high."Erlang poplar"(10-12)×P. cathayana (10-1)not only produced the most seeds but the germination rate and survival rate were also the highest. The survival rate of cuttage and transplant of combination of P. cathayana (10-25)×P. deltoids (10-19),"Erlang poplar"(10-12)×P. cathayana (10-1),"Erlang poplar"(10-12)×P. deltoids (10-19), P. szechuanica (10-22)×P. deltoids (10-19), P. trinervis (10-8)×P. deltoids (10-19) were higher.(3) The water and soil culture method was efficiently combined both the advantages of water culture and soil culture in breeding poplar branches which can obviously prevent flower and fruit from dropping and insured the success rate and the quality of fruits. The micro branches cottage had Significantly effects which increased to67.06%. The maximum survival rate can reach83.33%and the lowest was also above50%.(4) The isolated culture method of immature embryo is efficient for saving the immature embryo. The difference of the germination rate between different cross combinations was quite large. The highest germination rate was P. deltoids (10-15)×P. cathayana (10-1) which was68.75%, but P. deltoids (10-18)×P. lasiocarpa (10-21) did not germinate at all. The concentration of appropriate germination sugar among different cross group was different too. The optimum germination concentration of P. deltoids (10-17)×P. trinervis (10-9) was3%, but P. deltoids (10-18)×P. szechuanica (10-22) can well germinated at3%and5%, and P. deltoids (10-15)×R cathayana (10-1) can have the highest germination rate at7%.(5) The characters, growth and the level of damage by diseases and insect of hybrid seedlings were significant different. Their dispersal level was high and the selection foundation was wide which can have higher possibility to produce better offspring. The P. szechuanica (10-22)×P. deltoids (10-19) had the highest growth, the height of this group was over24.97%than average and the diameter was over18.8%than average. The P. trinervis (10-8)×P. deltoids (10-19) had the highest resistance to insect and P. yunnanensis (10-13)×P. trinervis (10-9) had the highest resistance to disease.(6) The broad heritabilities of combinations was bigger than individual ones. The heritability of hybrid combinations belong to higher heritability range and the individual heritability belong to lower heritability range, which indicated the group was suitable for the selection of cross combinations choice in order to get the maximum benefits. The GCA of P. deltoids (10-19) was the highest, and P. cathayana (10-1) was the lowest, which indicated the good characters could be stablely inherited and their offspring would present well. Furthermore, the SCA of P. szechuanica (10-22)×P. cathayana (10-1) and "Erlang poplar"(10-12)×P. cathayana (10-1) was higher than P. szechuanica (10-22)×P. deltoids (10-19) and "Erlang poplar"(10-12)×P. cathayana (10-1)(7) According to average value of each parameters and use the point system to give an overall evaluation, three cross combinations were primarily selected:"Erlang poplar"(10-12)×P. deltoids (10-19)、P. szechuanica (10-22)×P. deltoids (10-19)和P. trinervis (10-8)×P. deltoids (10-19). Then selected30individuals which had high growth and without diseased from these three combinations. The height gain of these30individuals increased31.85%～140.57%and the diameters gain increased27.51%～156.22%.