2018 ASHS Annual Conference

Korea National Arboretum has recently started the project ‘Wild Flowers’ for the commercialization of wild flowers native to Korea. In this project, we have selected 30 herbaceous (Euphorbia jolkinii, Minuartia laricina, Veronica kiusiana var. diamantiaca, V. pusanensis, Coreanomecon hylomeconoides, and etc.) and 6 woody species (Hydrangea serrata f. fertilis, Exochorda serratifolia, Lonicera insularis, and etc.) as new ornamental crops. The project consists of four contents : 1) floral market survey, propagation, and cultivation physiology including flowering control, 2) ornamental plants breeding, 3) model garden development, 4) finding traditional knowledge with the potential plants. Among the potential plants, Coreanomecon hylomeconoides (Papaveraceae) is a perennial herb and is endemic to Korea. This species has great potential as garden and landscape plant because it has long flowering period from May to September in Korea. However, C. hylomeconoides has seed dormancy at dispersal, and thus seed propagation is difficult. Ripe seeds were collected between 16~19 June. The seeds were sown in field soil in an experimental garden. We investigated the phenology of embryo growth, germination, and seedling emergence in the natural environment. Temperature requirements for embryo growth and germination were also determined by incubating seeds under controlled laboratory conditions. The effect of GA₃ concentrations (0, 10, 100, or 1000mg·L^-1) on dormancy breaking was also tested to characterize the type of seed dormancy. Seeds had underdeveloped embryos, which was about 13% in length of fully matured seed. When tested at the time of dispersal, seeds did not germinate during 4 weeks of incubation at 25/15 °C. Thus, C. hylomeconoides seed has morphophysiological dormancy. In natural conditions, embryos grew at temperature between 5 and 15 °C (average 10 °C) on late October. However, the seed did not germinate immediately after embryo elongation. After cold temperature season during winter, the seed germinated to about 80% when the temperature increased to 0~5 °C. More than 80% of seedlings emerged when the temperature increased to about 10 °C in the natural environment. None of the seeds germinated at 25/15 °C during 40 weeks of incubation whereas the seeds germinated to about 40% when the seeds were subjected to the temperature sequence (25/15 °C → 20/10 °C → 15/6 °C → 5 °C → 15/6 °C → 20/10 °C). The GA₃ treatment increased embryo growth in the seeds, but less than 20% of them germinated at 25/15 °C with 1000 mg·L^-1. Based on these results, seed dormancy of C. hylomeconoides can be broken through warm followed by cold temperature sequence and classified as having deep simple morphophysiological dormancy (MPD).