KOREASCHOLAR

This study was conducted to develop a seed propagation protocol of Hemerocallis taxa native to the Korean Peninsula. In this study, the seed dormancy types were classified. The germination traits of H. thunbergii, H. dumortieri, H. hakuunensis, and H. hongdoensis were also characterized. The initial embryo to seed length ratio (E:S ratio) in seeds of the four Hemerocallis species was between 0.80 and 0.90 at harvest, however, the E:S ratio did not increase until just before germination. Thus, seeds of the four Hemerocallis species had no morphological dormancy (MD), and at least 84% of seeds of all tested species germinated at 25/15℃ under light within 30 days. The lower the incubation temperature, the lower the germination rate of seeds of the four Hemerocallis species. However, the temperature range for germination was expanded due to old stratification. Gibberellin treatment increased the germination rate or germination speed at a relatively low temperature of 15/6℃. However, this treatment did not improve the germination rate as much as the temperature at 25/15℃. Under 15/5℃ of incubation, cold stratification increased the final germination percentage and rate/speed and expanded the temperature range for germination from high to low (25/15℃ → 15/6℃). This indicates that the seeds have a conditional dormancy (CD) that germinates in a narrow temperature range. In conclusions, the four Hemerocallis seeds exhibited nondeep physiological dormancy.

Introduction
Materials and Methods
    Plant materials
    Analysis of internal and external seed morphology
    Water absorption
    Effect of temperature on germination
    Effect of light on germination
    Effect of cold stratification
    Effect of GA3 treatment
    Statistical analysis
Results
    Internal and external seed morphology
    Water absorption rate
    Effect of temperature on germination
    Effect of light on germination
    Effect of cold stratification
    Effect of GA3 on germination
Discussion
Conclusions
Acknowledgments
References

• Gun Mo Kim(Department of Horticulture and Breeding, Graduate School of Andong National University, Andong 36792, Korea, Division of Wild Plant Seed Research, Baekdudaegan National Arboretum, Bonghwa 36209, Korea)
• Hak Cheol Kwon(Natural Product Informatics Research Center, Korea Institute of Science and Technology, Gangneung 25451, Korea)
• Yong Ha Rhie(Department of Horticulture and Forestry, Pai Chai University, Daejeon 35345, Korea)
• Chung Ho Ko(Garden and Plant Resources Division, Korea National Arboretum, Yangpyeong 12519, Korea)
• Seung Youn Lee(Department of Horticulture and Breeding, Graduate School of Andong National University, Andong 36792, Korea, Department of Smart Horticultural Science, Andong National University, Andong 36729, Korea) Corresponding author