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

Based on the results of the morphologic studies on genus Dioscorea, the paper summarized the entire chemical constituent that isolated from this genus and analyzed it with the methods of chemotaxonomy. The rules of the chemical constituent and pharmacodynamic effects were analyzed. Seventeen species which belong to Sect. Stenophora Uline of Dioscorea contain steroidal sapogenin. Other species with different main components such as polysaccharide and tannin have have different effects. This chemotaxonomic view point will conduce to establish a phylogeny of the genus Dioscorea.
Animals ; China ; Dioscorea ; chemistry ; classification ; genetics ; growth & development ; Humans ; Phylogeny ; Plant Extracts ; chemistry ; pharmacology

To establish a HPLC-ELSD fingerprint for total steroid saponins in herbs of Dioscorea zingiberensis. Welchrom C,8 (4. 6 mm x 250 mm,5 microm) chromatographic column was adopted and eluted with the mobile phase of acetonitrile (A)-water (B) at the flow rate of 1.0 mL min-1. The column temperature was room temperature. The ELSD conditions were as follows: the temperature of drift tube was 90.0 degreeC, the flow rate of carrier gas (N2) was 2. 8 L min-1, and the injection volume was 10 microL. After the detection of 10 batches of samples,the common mode of HPLC-ELSD fingerprint for total steroid saponins in herbs of D. zingiberensis was established for the first time,and 25 common peaks were determined. Among them, 10 peaks were identified by comparing with reference substances. The similarities of 10 batches of herbs were evaluated in the common mode. All of them were higher than 0. 80. This method is so accurate, reliable and highly repeatable that it can provide scientific basis for evaluating and controlling the quality of total steroid saponins in herbs of D. zingiberensis.
Chromatography, High Pressure Liquid ; methods ; Dioscorea ; chemistry ; classification ; cytology ; Saponins ; analysis

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

This article assessed the genetic relationship and genetic diversity in Dioscorea alata. Twenty samples were examined to identify their original plants, and analyzed by ISSR markers. The results showed that 20 samples were classified into three different plants, such as D. alata, D. persimilis, and D. fordii. There was significant difference in genetic similarity coefficient between D. alata and D. persimi as well as D. fordii. There was distinct differences in D. alata, the genetic similarity coefficient was resulted from 0.672 9 to 0.990 7. With UPGMA clustering method, 16 samples of D. alata could be divided into 4 groups. After comparing samples with the phenotypic characteristics of original plants, it showed that the color and the number of tuber were the most important characteristics of judging the genetic relationship of D. alata. It is concluded that the genetic variation of Dioscorea spp is significant, especially the genetic diversity in D. alata were in a high level. This article supplied a molecular biologic support for distinguishing Dioscorea spp, and also provided basis for breeding of D. alata.
DNA, Plant ; genetics ; Dioscorea ; classification ; genetics ; Genetic Variation ; Phylogeny ; Repetitive Sequences, Nucleic Acid

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.

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.