To utilize as the basic data for the crossing between Korean native and introduced azaleas, several studies were conducted such as the lethal temperature, alcohol concentration and pollen storage method. The results are summarized as follows:
1. The pollen viability of native azaleas such as Rhododendron mucronulatum, R. schlippenbachii, R. yedoense var. poukhanense was generally longer than introduced azaleas such as R. simsii hybrids (cv. Mission Bell) and R. mucronatum.
All azaleas except R. mucronulatum used in this experiment did not germinate after 150 days storage at room temperature condition, whereas pollen viability of R. mucronulatum showed less than 10%.
Native three azaleas increased the preservation ability as the temperature got below 5℃.
The pollen survival rate of the azalea showed high pollen survival rate at -20℃ as well as -10℃. R. simsii hybrids (cv. Mission Bell) and R. mucronatum did not survive at 5℃, and they showed less than 10% survival at -10℃ and -20℃.
2. Pollen viavility of native three azaleas were relatively kept very high in 60 days at 5℃, and the high pollen germination rate was maintained untill 150 days, while less than 10% survival rate except R. mucronulatum was obserbed after 300 days at 5℃ storage, the pollen germinations viability of R. obtusum (cv. Mother´s Day) were very low during whole period. R. japonicum showed more or less high pollen viability in 60 days whereas they were less than 10%, and completely dead after 300 days.
3. The pollen lethality by high temperature treatment on R. yedoense var. poukhanense wheres R. schlippenbachii was influenced to 50% survival under the treatment of 50℃ for one hour, whereas it was completely dead 50% for 16 hours in R. yedoense var. poukhanens, whereas R. schlippenbachii gave results less than 9% survival.
In the treatment of 70℃ for one hour and four hours pollen survival was very low and for 16 hours all were dead. While in the temperature of 90℃ treatment, they showed all death for one hour and for four hours and 16 hours as well.
4. In the pollen survival rate by the treatment of different concentration and dipping time of methyl alcohol, R. schlippenbachii was as a whole higher than R. yedoense var. poukhanense.
The most of pollens were survived by the treatment at the 25% concentration of methyl alcohol from one to 10 minutes dipping, whereas 50% concentration of it showed
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