Preliminary Study On Intergeneric Hybridization Within Chrysanthemum In Broad Sense(Ⅸ) Utilizations Of Hippolytia Germplasm Resources

There are lots of wild species in broad sense of Chrysanthemum with excellent resistance which can be utilized to improve the chrysanthemum cultivars’ resistance. The research included collecting wild germplasm resources in broad sense of Chrysanthemum and finding out the most efficient way for rapid propagation of Chrysanthemum mongolicum and Arctanthemum arcticum. It mainly focused on wide-cross breeding with the resources of Chrysanthemum, Hippolytia, Ajania and Brachanthemum. Some of the hybrids had ornamental hybridizations. F2 of inter-generic hybrids of Hippolytia and related genera showed the fertility of F1, which can be used in further cross breeding. The barrenness in some cross combinations was also discussed here. The main results and conclusion are listed as follows:1. The rare resources Chrysanthemum mongolicum and Arctanthemum arcticum were expanded by rapid propagation.The initial medium of them:MS+6-BA 1.00 mg/L+NAA 0.10 mg/Lwas more suitable. The multiplicative culture medium of Chrysanthemum mongolicum was:MS+6-BA 1.00 mg/L+NAA 0.05 mg/L. And MS+6-BA 1.00 mg/L+NAA 0.10 mg/L was more suitable for Arctanthemum arcticum.1/2 MS+NAA 0.20 mg/L was quite suit for rooting culture. It was the first time to use general multiplicative culture medium and out Test-tube rooting in broad sense of Chrysanthemum which could improve the efficiency of micro propagation.2. This research involved 7 generas,35 combinations and 16537 florets. At last,1055 seeds and 95 plants were obtained. Some important hybrids were identified by morphological, cytological and sequence analysis of the internal transcribed spacer. The confirmed real hybrids were Hippolytia trifida x C. chanetii, Hippolytia trifida x’Jinseqionglu’, Hippolytia trifida x (C. naktongense×C. argyrophyllum) and Ajania achilloides x(C. naktongense x C. argyrophyllum). 909 seeds were obtained from hybrids of Hippolytia trifida by Open Pollinated in natural condition.It proved the good fertility of F1.3. The research observed fertilization of the barrenness cross combinations.The results showed that the incompatibility was characterized by low pollen adhesion, low pollen germination and callose deposited on the stigma. It was the pre-fertilization barrier. On the other hand, the high temperature may lead to reduce the pollen viability and stigma receptivity of the crossing parents. Comprehensive analysis that the barrenness between Chrysanthemum, Hippolytia and Brachanthemum was caused by pre-fertilization, and it also Influenced by temperature of the environment.