This study was performed to identify optimal harvesting time of ginseng seeds and to examine the effect of GA3 treatment for improvement of seed stratification rate. Ginseng seeds harvested from Land race, Chunpoong and Yunpoong cultivar in July 20 were tested for stratification rate. It was shown that stratification rates of land race, Yunpoong and Chunpoong cultivar were 94.1%, 93.1%, and 82.6%, respectively. Seeds of Chunpoong cultivar harvested 10-15 days later showed a comparable stratification rate to that of Land race, indicating that late harvest of Chunpoong seeds is beneficial for the increase of stratification rate. The higher stratification rate was found in mature seeds (92.3%) than immature seeds (37.8%), both of which were harvested in July 20. Stratification rate of mature seeds harvested in July 15 was 87.5%, demonstrating optimal harvesting time of ginseng seeds with higher stratification rate is after mid-July. An exponential growth of endosperms of ginseng seeds was observed from early June to mid-June and then slow growth was observed. There was no obvious growth of embryos from fertilization to mid-August. After the this time, embryos quickly grew until late October. Thus, appropriate stratification control is essential during the period (from early September to late October) in order to optimize embryo growth and development. While no increase of stratification rate was observed in seeds treated with 50 ppm of GA3, significant increases were observed in seeds treated with 100 ppm of GA3. At this concentration of GA3, the stratification rate of Land race, Chunpoong and Yunpoong cultivar was 95.0%, 95.3%, and 96.5%, respectively.

This study was carried out to identify Korean ginseng cultivars using peptide nucleic acid (PNA) microarray. Sixty-seven probes were designed based on nucleotide variation to distinguish Korean ginseng cultivars of Panax ginseng. Among those PNA probes, three (PGB74, PGB110 and PGB130) have been developed to distinguish five Korean ginseng cultivars. Five Korean ginseng cultivars were denoted as barcode numbers depending on their fluorescent signal patterns of each cultivar using three probe sets in the PNA microarray. Five Korean ginseng cultivars, Chunpoong, Yunpoong, Gopoong, Gumpoong and Sunpoong, were simply denoted as '111', '222', '211', '221' and '122', respectively. This is the first report of PNA microarray which provided an objective and reliable method for the authentication of Korean ginseng cultivars. Also, the PNA microarray will be useful for management system and pure guarantee in ginseng seed.