A split-plot experiment was conducted to study the optimum planting density of Nuomi yam in directional groove shallow cultivation. Nuomi yam was the main local cultivar of Dioscorea. The study of this paper may help to give valuable instructions of local production. Three different planting densities and shallow groove diameter were designed in the experiment. The results showed that the fresh weight of aerial part per plant, yield and planting benefit of Nuomi yam tuber were the highest when the planting density was 12 000 plants/hm~2 and the diameter of shallow growth groove was 11.0 cm, while they were the lowest when the planting density was 22 500 plants/hm~2 and the diameter of shallow growth groove was 7.5 cm. Along with the increase of planting density, the fresh weight of aerial part, tuber, fresh yield, benefit and commercial tuber rate of Nuomi yam also decreased. The commercial tuber rate of Nuomi yam of 11.0 cm diameter in shallow growing pot was the highest, while it was the lowest with no shallow growing pot. On the contrary, the content of amylopectin and mucin was the highest when there was no shallow groove, and was the lowest when the diameter of shallow groove was 7.5 cm, although there was no significant difference between the two treatments. Therefore, Nuomi yam with the directional cultivation combination of planting density of 12 000 plants/hm~2 and shallow groove diameter of 11.0 cm showed high yield, good appearance quality, high planting benefit and no obvious adverse effect on internal quality.
Dioscorea

Leaf spot symptoms were frequently observed on yam plants grown in the Yeoju area in Korea during a disease survey in 2008. A total of five isolates of Pseudophloeosporella sp. were obtained from the infected leaves of yam plants. All of the isolates were identified as Pseudophloeosporella dioscoreae based on their morphological and cultural characteristics. A phylogenetic tree derived from the internal transcribed spacer sequences of the fungal isolates showed that the fungus is distinctly separated from species in other related genera. P. dioscoreae isolates caused very tiny spots on leaves of yam plants two weeks after artificial inoculation which were similar to those observed in the field. This is the first report that Pseudophloeosporella dioscoreae causes leaf spot in yams in Korea.
Cultural Characteristics ; Dioscorea ; Fungi ; Korea

During 2007 survey of post-harvest diseases of yam performed in May and June, severe tuber loss caused by blue mold was observed in Iksan, Cheonbuk Province. Two species of Penicillium were isolated from the infected tubers. Based on beta-tubulin gene sequence analysis, and cultural and morphological characteristics, the isolates were identified as Penicillium sclerotigenum and P. polonicum. P. sclerotigenum, which is a novel to Korea, is presently described and illustrated.
Dioscorea ; Fungi ; Korea ; Penicillium ; Sequence Analysis ; Tubulin

Animals ; Diabetic Nephropathies ; drug therapy ; Dioscorea ; chemistry ; Polysaccharides ; pharmacology ; Rats

To breed a new yam cultivar of Dioscorea alata, the different and excellent germplasm resources were investigated within artificially cultivated population and some superior individuals, with a higher yield and medicinal properties, were selected. Considering results of the yield and medicinal properties during 2006-2013 cropping season, strains and lines were established and selected. As a result, the yield of the new developed cultivar (Wenshanyao No. 1, WSY01-1) reached 2217. 0 kg per 667 m2 (fresh weight) and 348.3 kg per 667 m2 (dry weight), and increased 23.8% and 23.9% comparing with control cultivars (landraces). Comparing with control cultivars, the level of polysaccharide, allantoin, and dioscin increased 36.9%, 48.3%, 20.9%, and reached 12.2%, 1.30%, 579.7 µg · g(-1), respectively. This result showed that the systematic selection method can significantly improve yield and medicinal properties of D. alata, and the developed " Wenshanyao No. 1" exhibits wide spreading prospects.
Allantoin ; analysis ; Breeding ; Dioscorea ; chemistry ; genetics ; growth & development ; Diosgenin ; analogs & derivatives ; analysis ; Polysaccharides ; analysis

OBJECTIVETo study the production technology of extraction in combination hydrolysis in situ for isolating diosgenin from Dioscorea nipponica by orthogonal design.

METHODThe optimum production conditions were investigated with the recovery of diosgenin as an index by extraction in combination hydrolysis in situ, and were compared with the traditional method.

RESULTExtraction in combination hydrolysis in situ conducted in 1.5 mol x L(-1) sulfuric acid of water containing 75% isopropanol at 100 degrees C for 4.5 h could get higher recovery of diosgenin than traditional methods.

CONCLUSIONThis production technology can get higher recovery of diosgenin, and it is simple, time and money saving.

Dioscorea ; chemistry ; Diosgenin ; isolation & purification ; Hydrolysis ; Pressure ; Sulfuric Acids ; Technology, Pharmaceutical ; methods ; Temperature ; Time Factors

OBJECTIVETo develop an HPLC method for the determination of pseudoprodioscin in Dioscorea panthaica and provide scientific basis for quality control of it and its preparation.

METHODThe analysis was carried out on a Merck Purospher STAR RP-18e column eluted with acetonitrile and water as mobile phases in gradient mode. The detection wavelength was 203 nm, and the flow rate was 1.0 mL min(-1).

RESULTThe pseudoprodioscin in D. panthaica extract was well separated. The linear range is between 0.0800-4.00 microg, r =0.9999. The average recovery and RSD are 99.9% and 2.3%, respectively.

CONCLUSIONThis method for quantitation of pseudoprodioscin in D. panthaica is simple, accurate and reliable and can be used for the quality control of D. panthaica and its preparations.

Chromatography, High Pressure Liquid ; methods ; Dioscorea ; chemistry ; Diosgenin ; analogs & derivatives ; analysis ; Drugs, Chinese Herbal ; analysis

OBJECTIVETo extract polysaccharides from Dioscorea opposita by alpha-amylase and ultrasound.

METHODThe optimum condition of enzyme-assisted extraction has been obtained through orthogonal test according to the yield of polysaccharides.

RESULTA higher yield of polysaccharides was achieved at 55 degrees C, pH 5.5 , with a load of alpha-amylase 10 mg for 1.0 hour, the extraction rate was increased by in compare of sonolysis treatment alone.

CONCLUSIONTo carry out an enzyme treatment before ultrasound--assisted extraction elevated the yield of polysaccharides.

Dioscorea ; chemistry ; Hydrogen-Ion Concentration ; Polysaccharides ; chemistry ; isolation & purification ; metabolism ; alpha-Amylases ; metabolism

OBJECTIVETo study the chemical constituents of Dioscorea opposita.

METHODThe chemical constituents were isolated and purified by silica gel column chromatography, and the structures were elucidated by their spectroscopic data and physico-chemical properties.

RESULTTwelve compounds were obtained and identified as palmitic acid (1), beta-sitosterol (2), oleic acid (3), beta-sitosterol acetate (4), 5-(hydroxymethyl)furfural (5), nonanedioic acid (6), beta-daucosterol (7), cyclo-(Phe-Tyr) (8), cyclo-(Tyr-Tyr) (9), 6-methyl citrate (10), 1, 5-dimethyl citrate (11), trimethyl citrate (12).

CONCLUSIONCompounds 3-12 were isolated from this plant for the first time and cyclodipeptides were firstly isolated from the Dioscoreae family; Compound 9 was a new natural product.

Chromatography, Gel ; Dioscorea ; chemistry ; Drugs, Chinese Herbal ; chemistry ; Magnetic Resonance Spectroscopy ; Mass Spectrometry

Making textual research on Bencao and documents, this article inquires to the origin and development of genuine medicinal herbs of Shanyao (Rhizoma Dioscoreae) on the points of change of the growing areas and the development of cultivating and processing techniques and clinical uses. The study indicates that the medicinal use of Dioscorea oposita went through several periods: the period of the use of wild D. oposita before Tang dynasty, the period of the mixed use of wild and cultivating D. oposita from Song to the middle of Qing dynasty, and the period of the main use of cultivating D. oposita after the latter stage of Qing dynasty (18th century). It considers that the growing area of genuine medicinal herbs of Shanyao appeared in Ming dynasty and finally formed "Huaishanyao" on the early of 20th century. The acknowledgement of Huaishanyao as genuine medicinal herbs is related closely to its cultivating and processing techniques and clinical uses. The development of cultivating techniques provided the resource of Shanyao, the invention of processing techniques improved its appearance and quality, and the clinical uses and practices by modern and contemporary famous medical men played an important role to the social approval and development of Huaishanyao.
Dioscorea ; growth & development ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Phytotherapy ; methods