Background : Rehmannia glutinosa root (R. root) has been used as traditional medicine, and is important resource for natural medicines and functional foods. However, R. root have catalpol which have bitterness, and undigested sugars, including stachyose, raffinose, and verbascose as main compounds, and these compounds can cause diarrhea and abdominal pain. Therefore, this study was performed to determine the changes in reducing sugar producted from undigested sugars and catalpol contents as a bitter taste compound in R. root with aging treatment conditions. Methods and Results : R. root was treated at 10 - 70℃ for 0 - 48 h, and extracted with 50% ethanol solution. Their catalpol content was analyzed using HPLC-UVD, reducing sugar content generated from undigested sugars was measured by the Nelson-Somogyi methods, and these reaction rates were calculated from their variation according to aging time and temperature. During aging treatment, reducing sugar content increased and catalpol content decreased. Their formation and degradation rates were highest at 50℃ and 30 - 40℃, and their rates were 1.89 ㎎/g·h and 23.09 - 23.33%/h, respectively. Conclusion : These results indicated that aging treatment can positively affect the sweetness and digestibility of R. root slurry. Therefore, aging treatment could be considered for improving the sensory qualities and digestibility of R. root.

Background : Rehmannia glutinose Liboschitz is a perennial herb belonging to the family of Scrophulariaceae. Its roots have been used as a traditional medicine. For cultivation of varieties of Rehmannia glutinose Liboschitz, the pure line selection method, which is to select the best line among those cultivated in farms for pedigree breeding, replicated yield test and regional adaptation test before registering as a new variety, is widely used. Until now, there are 8 registered varieties of Rehmannia glutinose Liboschitz in Korea. The needs for development of disaster-resistant varieties with better chances of surviving when high temperature, salts and disease are increasing. Therefore, this study focused on cultivation of disaster-resistant varieties among those selected for their disaster tolerance and salt tolerance through regional adaptation test. Methods and Results : As a result of examining the incidence of pest insects of the selected 1 - 2 years old varieties used in the study, among the 2-years-old crops, RGES 20 showed the lowest rate in ground parts. Among the 1-year-old crops, the lowest rate incidence of pest insects in ground parts was observed in RGES 23. In addition, RGES 20 and RGES 23 showed superior growth in under ground part with the highest dry root amount. Conclusion : Based on the above results, RGES 20 among the 2-years-old crops, RGES 23 among the 1-year-old crops showed superior growth in under ground part with the highest dry root amount.

Background : Rehmannia glutinosa belonging to the family of Scrophulariaceae have been utilized as a traditional medicine. This study was conducted to elucidate an effect of air curing for seed rhizome of R. glutinosa on storaging ability and yield. Methods and Results : The root of R. glutinosa cultivar (Dagang) was harvested in the end of November. Seed rhizomes were air curing for one to seven days then wrapped with newspaper and further stored in a plastic container box at 1℃. The weight loss and decay rates were significantly lower in seed air curing treatment than in untreated. Especially, the decay rate of control was approximately 50% at 120 days after storage. But, the decay rate of all air curing treatment groups was less than 1%. Also air curing led to an increase in germination rate of seeds and root yield compared with untreatment. Taken together, the best air curing treatment period was 3 days, under the that conditions, germination rate and yield were 88.7% and 2,185 ㎏/10 a, respectively. Conclusion : This study has successfully demonstrated that the air curing of rhizome as a seeds led to considerable increasement of both storaging ability and yield in R. glutinosa.

Background: Rehmannia glutinosa is a perennial herb belonging to the family Scrophulariaceae. Its roots have been utilized as a traditional medicine. The aim of this study was to elucidate the basic information of the roots of the R. glutinosa cultivars and their utilization. Methods and Results: The roots of R. glutinosa cultivars were harvested in the end of March. The two iridoid glycosides, aucubin and catalpol, were analyzed by liquid chromatography/mass spectrometry (LC/MS), whereas γ-aminobutyric acid (GABA) was analyzed by gas chromatography/mass spectrometry (GC/MS). The aucubin content was the highest in the Dakang cultivar, whereas no aucubin was detected in the five cultivars. All cultivars had more than 12 ㎎/g catalpol content, and the maximum catalpol content was found in Jihwang 1. The GABA content was the highest in Suwon 1, and it was 40 times more than that in the Yeongang cultivar. Conclusions: The highest aucubin, catapol and GABA contents were detected in the Dakang, Jihwang 1, and Suwon 1, cultivars respectively. This study provides the crucial information regarding the versatile utilization and pedigree selection of R. glutinosa cultivars.

Background : Rehmannia glutinosa is a perennial herb belonging to the family Scrophulariaceae. Its roots have been utilized as a traditional medicine but the aerial parts (flower, flower stalk, leaf) were not used. In this paper, we aimed to determine the content of three compounds [aucubin, catalpol, and γ-aminobutyric acid (GABA)] in different organs of R. glutinosa. Methods and Results : The flower, flower stalk, leaf, and root of R. glutinosa were harvested in the end of August. The aucubin and catalpol were analyzed by LC/MS, whereas GABA was analyzed by GC/MS. The aucubin content was the highest in the leaf, while catalpol and GABA were the highest in the flower. The aucubin content of in the leaf was 1.43, 0.81, and 1.07 ㎎/g, respectively. The catalpol content of flower in Dakang, Tokang, and Suwon 9 was 41.06, 28.78 and 37.48 ㎎/g, respectively. The GABA content of flower in Dakang, Tokang, and Suwon 9 were 0.79, 0.76 and 0.65 ㎎/g, respectively. Conclusions : The contents of aucubin, catalpol, and GABA were higher in leaf and flower than that of root. This study provides the important information of R. glutinosa leaf and flower as a potential supplement.

Background : In the year 2015, the area under rhizome of Rehmannia glutinosa in Chungnam province increased to 65% (105 ha) of domestic total cutivation area and is recognized as income crop. Since proper strorage method of rhizome has not been established, rhizome decay rate is so high during storage. This experiment was carried out to establish proper strorage method for stable production of rhizome of Rehmannia glutinosa Methods and Results : Korea jiwhang was used for this experiment and rhizome was cured under vinyl house and room temperature for 1, 2, 3 days respectively. Rhizome was stored for 140 days at –2 - 0℃ after curing, and rhizome quality and saprogen were investigated after storage. Trimming loss was 11.3 - 21.9%, higher in longer curig time and rice hull packing. Moisture content was 70.0 - 75.1%, higher in shorter curing time and no rice hull packing. Curing efficacy was better in vinyl house than room temperature, decay rate by weight and number of rhizome was lowest in 48hrs curing and no hull packing as 0.5% and 2.0% respectively. Identified saprogen during storage was Fusarium oxysporum, Fusarium tricinctum, Penicillium verrucosum, Mucor racemosus. Conclusion : Curing efficacy was better in 48hrs treatment under vinyl house with lowest decay rate and rice hull packing increased decay rate considerd due to saprogen existing in rice hull. 4 saprogens including Fusarium oxysporum were identified during storage of rhizome.

A new Rehmannia glutinosa cultivar ‘Tokang’ was derived from ‘Jihwang 1’ seedlings by medicinal crop breeding team of National Institute of Horticulture and Herbal Science, RDA in 2009. It has pink flower, dark brown seed coat, light yellow root cortex. The plant type was some rising from the ground. The content of catalpol and extract were higher than the ‘Jihwang 1’(check variety). The content of catalpol was 4.55% and the extract was 71.2%. It showed stronger resistance to root rot compare with the ‘Jihwang 1’. The regional yield trials were conducted at three different locations from 2007 to 2009. The average yield of ‘Tokang’ was 21.1ton/ha, which was 12% more than the ‘Jihwang 1’. This cultivar is adaptable to the whole of Korea except for mountain areas. (Registration No. 4725)

Background: Rehmannia glutinosa is a perennial herb belonging to the family Scrophulariaceae. Its root has been utilized as a traditional medicine but the aerial parts (flower, flower stalk, leaf) are not used. We aimed to determine the content of three compounds [aucubin, catalpol, and γ-aminobutyric acid (GABA)] in the different organs of R. glutinosa cultivars (Dakang, Tokang, and Suwon 9) Methods and Results: The flower, flower stalk, leaf, and root of R. glutinosa were harvested at the end of August. The aucubin and catalpol contents were analyzed by LC/MS, whereas the GABA content was analyzed by GC/MS. The aucubin content was the highest in the leaf, while catalpol and GABA were the highest in the flower. The aucubin contents of leaf in Dakang, Tokang, and Suwon 9 were 1.43, 0.81, and 1.07㎎/g, respectively. The catalpol contents of flower in Dakang, Tokang, and Suwon 9 were 41.06, 28.78, and 37.48㎎/g, respectively, the GABA contents were 0.79, 0.76, and 0.65㎎/g, respectively. Conclusions: The aucubin, catalpol, and GABA contents were higher in the leaf and flower than that in the root. This study show that R. glutinosa leaf and flower can be used as a potential supplement.

Background : This study was development of moisture tolerance and high-yielding Rehmannia glutinosa cultivar. Methods and Results : Segang is developed by the medicinal crop breeding team of National Institute of Horticulture and Herbal Science(NIHHS), Rural Development Administration(RDA), during the period from 2005 to 2015. The reproduction of Rehmannia glutinosa has been accomplished mainly by vegetative propagation with its seedlings have many variants. The cultivar was selected from seedling of Jihwang 1(check variety). The plant type of Segang is some rising from ground. Regional yield trials conducted at three site from 2014 to 2015. The root yield of Segang was 21.1ton per hectare, which was increased 12% compared with Jihwang 1. Also, Segang has higher catalpol content and dried root ratio compared with Jihwang 1. Conclusion : Segang is a moisture tolerance and high-yielding Rehmannia glutinosa cultivar.

Background : Jiwhang (Rehmannia glutinosa L.) cultivation area of chungnam province was 62ha(219 farms, 53.9% of domestic cultivation area, M.A.F.R.A. 20142)). Recently, jiwhang is rapidly spread to 150ha ( Geumsan administration statistics, 2015) as taking place of income crop in Chungnam. High quality jiwhang GAP production and improvement of the distribution system including magnus customers, producer association fosterage and conventional market Vitalization were the reason of rapid cultivation area increase of Rehmannia glutinosa L. in Geumsan. This study was performed to set up the standard Rhizome size for planting in Rehmannia glutinosa L. Materials and Methods ○ Experiment variety : Togang ○ Treatment(rhizome length) : ① 1cm ② 2cm ③ 3cm ④ 4cm ⑤ 6cm(control) ○ Planting date : May 6, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : In the aboveground growth was no significant difference among treatments. In the root characteristics, there was no significant difference among treatments. Take a 1∼2cm rhizome planting saved rhizome amount and planting time to 73.8%∼64.3% and 68.4%∼ 57.8% respectively than 6cm(control).

Background : Generally, price of Jiwhang(Rehmannia glutinosa L.) is highest in August. In this study, Economic Evaluation and Productivity of 9 Jiwhang varieties w ere analyzed according to harvesting tim es of August and October. Materials and Methods ○ Experiment variety : Jiwhang 1, Korea jiwhang, Daegyung, Gogang, Togang, Dagang, Wongang, Hwanggang and Yeongang ○ Treatment : ①Initial-August harvest ②Mid-August harvest ③Ended-August harvest ④Ended-October harvest ○ Planting date : April 17, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : The higher roots yield at August harvest was in Gogang, Dagang and Togang. The lower roots yield at August harvest was in Korea jiwhang and Hwanggang. The higher economic feasibility at August harvest was in Gogang, Togang, Dagang and Wongang. The higher economic feasibility at ended-October harvest was in Gogang, Yeongang, Togang, Dagang and Wongang.

Background : According to medicinal plant standard culture, flower stalk should be removed at the stage of 4-5 main leaves appearance but there is no detail information on stalk removal in jiwhang (Rehmannia glutinosa L.). This study was carried out to examine effect of flower stalk removal on the increase of total yield in Rehmannia glutinosa L. Materials and Methods ○ Experiment variety : Korea jiwhang, Wongang ○ Treatment : ① Peduncle non-cutting ② Peduncle cutting ○ Planting date : April 18, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : Aerial part growth was no significant difference according to treatments in Wongang and aerial weight was havier in Peduncle cutting than in Peduncle non-cutting. Aerial part growth was no significant difference according to treatments in Korea jiwhang. The roots yield in Korea jiwhang was increased about 5.2% in Peduncle cutting. The roots yield in Wongang was increased about 24.9% in Peduncle cutting.

Background : Jiwhang (Rehmannia glutinosa L.) cultivation area of Chungnam province was 62ha (219 farms, 53.9% of domestic cultivation area, MAFRA. 20142)**). Recently, jiwhang is rapidly spread to 150ha (Geumsan administration statistics, 2015) as taking place of income crop in Chungnam. High quality jiwhang GAP production and improvement of the distribution system including magnus customers, producer association fosterage and conventional market vitalization were the reason of rapid cultivation area increase of Jiwhang in Geumsan. But low emergence rate caused by spring drought should be solved. This study was carried out to obtain basic data for emergence rate improvement in jiwhang. Materials and Methods ○ Experiment variety : Korea jiwhang ○ Treatment : ①Control ② 1 time irrigation at planting time ③1 time irrigation at planting time + transparent vinyl mulching ○ Planting date : April 30, 2015 ○ Planting distance : 30×15cm ○ Experiment place : Ginseng and Medicinal Plant Research Institute (Geumsan-gun, Chungcheongnam-do) Conclusion : There was no significant difference in the aboveground growth among treatments. The seedling emergence rate was higher in 1 time irrigation at planting time + transparent vinyl mulching(1ITVM) than control or 1 time irrigation at planting time(1I). Aerial part weight was significantly havier in 11ITVM than control or 1I. The roots yield was also more in 1ITVM than control or 1I. According to economic analysis, total income in 1ITVM compared to 1I and control was 125.1% and 54.0% higher respectively.