Establishment Of Regeneration System Of Rhododendron Chrysanthum Pall.Leaves And Studies On The Interspecific Hybridization

In this study, the Rhododendron chrysanthum Pall. of Changbai Mountain and its tissue cultured plantlet, Rhmucronulatum Turcz., Rhmucronulamm Turcz.f.album Nakai, Yabuli dujuan and Rh.schlippenbachii Maxim. as test material, the factors which influence the leaf differentiation of Rh.chrysanthum Pall and the cross compatibility of Changbai Mountain rhododendron’s interspecific hybridization were studied. It is expected to lay a solid foundation for selection on somaclonal variation and germplasm innovation. The results were as follows:1. The effects of TDZ on leaf callus induction and differentiation was significantly better than ZT, the best medium was modified MS+TDZ0.2～0.5mg·L-1+IBA0.5mg·L-1the differentiation rate up to97.44%. After subculture all multiple shoots can be elongation growth. The average differentiation number of adventitious buds up to37.75. But the effect of TDZ on proliferation was not as well as ZT in subculture.2. Root growth situation of tissue culture seedling of Rh. chrysanthum Pall.was better on the medium of modified MS+IBA0.5mg·L-1+Active Carbon2.0g·L-1, rooting rate up to91.11%. The better transplanting medium of plantlets was peat soil:humus soil:perlite=2:1:1, survival rate was reached88.33%.3. There is a significant difference compatibility of reciprocal cross of rhododendron’s interspecific hybridization. When the Rh. chrysanthum Pall. as female parent, hybrid with Rh.mucronulatum Turcz., Rh.mucronulamm Turcz.f.album Nakai, Yabuli dujuan, the fruit set percentage of three hybridized combination in harvest time was respectively92.55%,94.14%,92.42%, and it have no significant difference with control group (the Rh.mucronulatum Turcz. spontaneous pollination). But when the reciprocal cross, the fruit set percentage was significantly decreased, the fruit set percentage of Yabuli dujuan×Rh. chrysanthum Pall. is the highest, it was36.51%; hybrid with Rh.mucronulatum Turcz. was6.52%; hybrid with Rh.schlippenbachii Maxim. was0.4. The optimal medium for seed embryo culture of Rh. chrysanthum Pall. was Read+GA32.0mg·L-1, when direct cross the hybrid embryo’s germination rate of Rh.chrysanthum Pall hybrid with Rhmucronulatum Turcz.,Yabuli dujuan and Rh.schlippenbachii was respectively13.60%,11.59%,4.12%. The growth of hybrid seedlings was weak, it has more albino seedlings and found that hybrid seedlings showed up abortion. After subculture two or three times, the growth status of hybrid seedlings has recovered modestly, and the differentiation rate was significantly higher than the control, but the colour of plants still flavo-green. But in the reciprocal cross, the hybrid embryo’s germination rate of Yabuli dujuan×Rh.chrysanthum Pall. was significantly higher than the direct cross, the germination rate as high as39.81%, and the growth of hybrid seedlings was very strong and there is no need to subculture. After3months culture in the embryo culture medium, the hybrid seedlings can be directly acclimatization and transplanting.5. Suitable for Rhododendrons hybrid seedlings rooting medium was1/2Read+IBA0.5mg·L-1+Active Carbon2.0g·L-1, after40days cultivate, the rooting rate reached60%.