Crossing Experimentation Of Several Catalpa And Variation Of Clones

Pollen morphology of Catalpa Scop.was observed,the pollen vitality,the feasibility of cross-breeding,the variation of germplasm resources of Catalpa bungei C.A.Mey.and Catalpafargesii Bur.f.fargesii was studied emphatically,all investigations provide theoretic foundation for further utilization and innovation of germplasm resources.the major research results were summarized as follows:1.Pollen morphology of Catalpa Scop.was observed,all of them were aggregated into tetrad.The difference among these species is mainly in the size and exine sculpture of the pollen tetrads,the pollen of Catalpa speciosa(Warder ex Barney)Engelmann is the largest with 55.8μm in average,Catalpa ovata G.Don is the smallest with 42.4μm,among them are Catalpa fargesii Bur.f duclouxii(Dode) Gilmour 52.9μm,Catalpa fargesii Bur.f.fargesii 47.2μm,Catalpa bungei C.A.Meyer 42.7μm in tum,Catalpa bungei C.A.Meyer is similar with Catalpa fargesii Bur.f.duclouxii(Dode)Gilmour in exine sculpture,and that,Catalpa fargesii Bur.f fargesii,Catalpa ovata G..Don and Catalpa speciosa(Warder ex Bamey)Engelmann are semblable.2.Pollen vitality of three Catalpa bungei of Catalpa Scop.were studied.The results shown that the optimal terms of pollen germination in vitro were consistent.Variance of pollen germination rate showed obvious significance among infraspecific individuals.3.Intraspecific and interspecific hybridization of Catalpa Bungei C.A.Mey.were undertaken using traditional approaches,results indicate that interspecific hybrids showed better growth performance,therefore,during the future breeding work,interspecific hybridization should be undertaken actively,moreover,the selection of male and female parents should given more attention.4.Abundant variation exists among Catalpa bungei C.A.Mey.clones,the results of principal component and cluster analysis provide theoretic foundation for male and female parents selection.5.Extensive variation exists among and within provenances of Catalpa fargesii Bur.f fargesii,the variation among provenances was the mainly variation source,accordingly,the superior provenances will become the principal choice of eximious clones and male or female parents.