| [objective]Yams (Dioseoreas pp.) are extremely important food crops in world belonging to the section Enantiophyllum of Dioseoreas genus, and embodied pharmacopoei-as in many countries because of its important medical effects. China was one of important yam domestication center, So far, four different species in Dioseoreas genus has been widely cultivated, of which was Dioscorea opposita Thunb.(Dioscorea oppostita Rhizome), Dioscorea alata Linn.(Dioscorea alata Rhizome), Dioscorea persimilis Prain et Burkill.(Dioscorea Persimilis Rhizome),and Dioscorea fordii Prain et Burkill.(Dioscorea fordii Rhizome) respectively. Thus, yam has presented a challenge to clarification due to numerous cultivars and lacking of optimum classification standards, yam germplasm resources has not still been clarified especially in genetic diversity and genetic relationship aspects. Additionly, because of different species Dioscorea Rhizomes, the identification and inherent quality evaluation of Dioscorea Rhizomes has also been a big difficult points. Therefore, it was very necessary to reveal genetic relationship and Rhizome quality difference among different yam species, in order to solve yam cultivars confusion and ensure Dioscorea Rhizomes used accurately. Thus, in this study, we studied emphatically genetic diversity, genetic relationship and quality evaluation by collecting differrent yam cultivars and different original Dioscorea Rhizomes. This study aim was to provide reliable molecular evidences for classifying yam cultivars and making clear genetic relationship, also to clear quality difference and situ ation in different speceies Dioscorea Rhizomes, further, in order to provide scientific proof for use safely of yam.[Methods and Contents]1. Study on genetic diversity in yam germplasm resources based on DNA molecular markersInter-simple sequence repeats (ISSR) molecular markers, sequence-related amplified polymorphism(SRAP) molecular markers and combining both kinds of molecular markers were applied to detect genetic diversity of twenty one yam cultivars belonging to four main yam species cultivated in China. As a result, We collected sixty one samples from eight populations. POPGENE software(ve-rsion1.32)counted respectively parameters such as observed number of alleles(Na), the percentage of polymorphic loci (PPB), Shannon’s Information index(I), Nei’s gene diversity index(h), Nei’s genetic distance(GD), the total genetic diversity(Ht), genetic flow(Nm), etc. Mega software(version4.1) carried out UPGMA(Unweighted Pair Group Method Arithmetic Averages) clustering and principal component analysis. These data was correspondingly used to explain genetic diversity, cultivars belonging, genetic relationship among species, genetic differentiation characteristics in populations.2. Study on genetic relationship in yam germplasm resources based on DNA sequenceFourteen genotypic selected in term of genetic diversity were regarded as materials. DNA Sequencing technology was utilized to sequence ITS and rbcL. Clustal x software(version1.83) performed multiple sequence alignment, and calculated nucleotide proportion of each sequence, obtained finally genetic distance and the number of nucleotide difference between each two sequences. Furthermore, mega software(version4.1)constructed the phylogenetic trees with the neighbor joining method and maximum parsimony method. The phyloge-netic trees reconstructed were used to reveal genetic relationship and evolution characteristics about yam germplasm resources in China.3. Study on identification of Dioscorea RhizomesCharacter observation, digital microscopic observation of tubers and leaves, thin layer chromatography, fourier transform infrared spectroscopy, was made one by one to find difference of four species conventional Dioscorea Rhizomes in China.4. Heavy metal, SO2detection and quality safety assessment of Dioscorea RhizomesThe Pb, Cd, As, Hg, Cu content were determined according to the method Chinese Pharmacopoeia (edition2010) appendix IX B. Meanwhile, we also analyzed SO2content by the method of Chinese Pharmacopoeia (edition2010) appendix Ⅸ U. In addition, we evaluated medical and edible safety by means of the method of single factor pollution index and Nmerow’s comprehensive pollution index(P), based respectively on green standards of medicinal plants and preparations for foreign trade and economy(WM/T2-2004), and correlation food standards.5. Comparative study on carbohydrate components of Dioscorea RhizomesOrthogonal test was designed with extraction temperature, ethanol concentration, solid-liquid ratio and reflux time as factors, to optimize extraction process of yam oligosaccharide; and response surface methodo-logy was also taken to optimize extraction process of yam polysacchari-de. Referring to the optimum processes acquired, Oligosaccharide and polysaccharide components were firstly extracted, and UV spectrophotom-etry was employed to determine contents in different species Dioscorea Rhizomes, lastly corresponding results were used to reveal carbohydrate components difference in different species Dioscorea Rhizomes.6. Study on determination of allantoin in Dioscorea Rhizomes by HPLC-DADHigh efficiency liquid chromatography equipped with DAD detector was used; to determine allantoin content, and constructed effective and sensitive determination method, we compared subsequently allantoin content difference in different species Dioscore Rhizomes7. Comparative study on saponin components in Dioscorea RhizomesUV spectrophotometry and high efficiency liquid chromatography equipped with DAD detector were utilized respectively to determine totally saponin content and dioscin content. Furthermore, we analyzed saponin components difference in Dioscorea Rhizmoesin the light of corresponding results. High performance thin layer chromatography was also employed to show special difference and common pattern in different species Dioscore Rhizomes.[Results]1. Study on genetic diversity in yam germplasm resources based on DNA molecular markers1.1Genetic diversity of yam germplasm resources detected by Inter-simple Sequence Repeats (ISSR) Molecular MarkersEleven primers produced150clear bands, among them143was polymorphic bands, the average percentage of polymorphic bands was95.3%. The Nei’s gene diversity index(H) was0.2980, Shannon’s Information index(Ⅰ)was0.4560, total genetic diversity(Ht)was0.3168, these informative charact-ers indicated extremely high genetic diversity level among yam populations. While the genetic diversity level within populations presented distinct difference, of which HNWX population was the highest (PP6=51.33%), the FJSM population was the lowest (PPb=0%). The genetic differentiation coefficient (Gst=0.7996) and genetic flow (Nm=0.0698) also showed that genetic diversity level among populations was higher than within populations. All populations were divided into four groups corresponded to their cultural species, based on genetic distance(GD) from0.0712to0.5032. Furthermore, all investigated cultivars could be also indentified truly and classified into four species by UPGMA cluster analysis, in light of genetic di stance (GD) from0.0154to0.7225.1.2Genetic diversity of yam germplasm resources detected by sequence-related amplified polymorphism(SRAP)molecular markersAs a result,309bands were amplified by sixty combinative SRAP primers, of which289bands were polymorphic bands, the average percentage of polymorphic bands was93.53%. Just like ISSR study, the Nei’s gene diversity index (H=0.2881), Shannon’s Information index (1=0.4416) and total genetic diversity (Ht=0.2891) identically revealed extremely high genetic diversity level among yam populations. Within populations, HNWX population had the highest genetic diversity(PPb=40.96%), whereas the genetic diversity was the lowest in FJSM and ZJRG populations, the difference within populations was relatively huge. The genetic differentiation coefficient (Gst=0.8658) and genetic flow (Nm=.0075) showed the same rule that genetic diversity among populations was higher than within populations. The genetic distance(GD)of all populations ranged0.0498-0.4879, well-separated groups were also formed that corresponded to their cultural specie. In the same way, twenty one inves-tigated cultivars could be distinguished by SRAP markers, and these cultivars could be fell effectively into four species that corresponded to Dioscorea opposita Thunb., Dioscorea alata Linn., Dioscore persimilis Prain et Burkill. and Dioscorea fordii Prain et Burkill.1.3Genetic diversity of yam germplasm resources analyzed base on combining ISSR markers and SRAP markersMantel test presented significant relativity between ISSR markers and SRAP markers(r=0.9523). With combined ISSR matrix characters and SRAP matrix characters, the average percentage of polymorphic bands was found up to94.12%, Nei’s gene diversity index(H)was up to0.2912, Shannon’s information index was up to0.4462, the genetic differentiation coefficient was up to0.8336, these showed very high genetic diversity level in all populations. Further analysis, it was found that genetic diversity among four yam species took up main part with83.36%of total genetic diversity, on the other hand, genetic diversity within species took only up16.64%. At different yam species level, we found that the average percentage of polymorphic bands presented the trend of Dioscorea opposite(62.31%)> Dioscorea alata (31.15%)> Dioscorea persimilis(12.20%)> Dioscorea fordii (5.88%). The genetic distance among four species ranged0.2749-0.4255, of which genetic distance between Dioscorea opposite and Dioscorea alata was the minimum, the genetic distance between Dioscorea fordii and Dioscorea persimilis was the maximum.2. Study on genetic relationship in yam germplasm resources based on DNA sequence2.1Comparative study on chloroplast rbcL sequences of fourteen genotyp-ic yamsAs a result, fourteen rbcL sequences was obtained by amplifying rbcL gene fragment from fourteen genotypic yams, of which the length ranged1115bp-1168bp, the contents of G+C was from43.9%to44.5%. When the gaps were always treated as missing, there were19variable sites, among them parsim-info sites and singletion sites were respectively6and13, and the transition/transversion bias was2.066. Among fourteen genotypic yams, the genetic distance calculated using the Kimura two-parameter model was from0to0.0118, and the number of nucleotide difference between each two sequences was from0to14. Dioscorea zinguverebsus(accession:AY939889) was regarded as outgroup, the phylogenetic trees (length=601, CI=0.9983, RI=O.9231) with stable topology structure was obtained by the maximum parsimony analysis, results showed that rbcL sequences was very conservative. The phylogenetic trees indicated that genetic relationship between Dioscorea alata and Dioscorea fordii, between Dioscorea opposite and Dioscorea persimilis were very close, whereas which between Dioscorea opposite and Dioscorea fordii was relatively distant.2.2Comparative study on ribosome ITS sequences of fourteen genotypic yamsAs another results, we also obtained fourteen ITS sequences by means of cloning ITS aim fragment from fourteen genotypic yams, of which the length were from558bp to594bp, the contents of G+C was from45.6%to52.6%. When the gaps were treated as missing, ITS1had137variable sites, of which117was parsim-info sites; ITS2had122variable sites, where117was parsim-info sites, and the transition/transversion bias was5.347. The K2-P genetic distance ranged0-0.5172, the number of nucleotide difference between each two ITS sequences was from0to184, results showed great genetic difference among all genotypic yams. In this part study, we took Dioscorea collettii var. hypoglauca (accession:DQ267931)as outgroup, and constructed the phylogenetic trees based on ITS sequences analysis. Likewise, the phylogenetic trees also indicated that genetic relationship between Dioscorea alata and Dioscorea fordii were close, and which between LNS genotypic belonging to Dioscorea opposite and Dioscorea persimilis was specially close.3. Study on identification of Dioscorea Rhizomes3.1Study on identification of Dioscorea Rhizomes based on observing character and digital microscopic imagingIn medicinal materials characters hand, the surface of Dioscorea oppostita Rhizome and Dioscorea persimilis Rhizome presented relatively smooth, whereas of which Dioscorea alata Rhizome and Dioscorea fordii Rhizome were comparatively rough. On the other hand, The differences of tuber microscopic characters were as fellows:Dioscorea oppostita Rhizome had not stone cell ring at pericycle; Dioscorea alata Rhizome presented connective or unconnective stone cell ring, and mucin cells were mainly distributed in cortex; Dioscorea persimilis Rhizome showed connective and thin stone ring; the stone ring of Dioscorea fordii Rhizome was connective and relatively thick. Leaves microscopic characters were comparatively similar.3.2Study on identification of Dioscorea Rhizomes by using thin layer chromatographyAs a result, Dioscorea oppostita Rhizome and control medicinal materials performed same spots, but the brightness of them showed a little difference; Comparing control medicinal materials with Dioscorea fordii Rhizome, Dioscorea alata Rhizome and Dioscorea persimilis Rhizome respectively, there were also slight difference of spots performed. Among four species Dioscorea Rhizomes, Firstly, at the situation of0.85R-fvalue, Dioscorea oppostita Rhizome with bright spot, while Dioscorea alata Rhizome with indistinct spots, which was distinguished from the other two species without any spots. Furthermore, at the situation of0.4R-fvalue, Dioscorea fordii Rhizome and Dioscorea persimilis Rhizome were separated in term of spots differences.3.3Study on identification of Dioscorea Rhizomes by using fourier transform infrared spectroscopyAs a rule, IR fingerprint spectra was relatively similar among four species conventional Dioscorea Rhizomes. But IR difference occurred more remarkably in the second derivative spectra. For example:at2348cm-1, Dioscorea oppostita Rhizome, Dioscorea alata Rhizome, Dioscorea persimilis Rhizome and Dioscorea fordii Rhizome had more intensity absorption peaks than control medicinal materials; at1739cm-1, a sharp absorption peaks was also presented in Dioscorea persimilis Rhizome and Dioscorea fordii Rhizome, of which the former was stronger, whereas the other two species without peaks; besides, at1707cm-1, the order of absorption intensity was showed, Dioscorea persimilis Rhizome>Dioscorea fordii Rhizome>Dioscorea alata>Dioscorea oppostita Rhizome; moreover, there were also three continuous asborsption peaks at1446cm-1,1427cm-1and1409cm-1respectively in Dioscorea persimilis Rhizome and Dioscorea fordii Rhizome, which could be used to distinguish the other two species.4. Heavy metal, S02detection and quality safety assessment of Dioscorea RhizomesIn all investigated Dioscorea Rhizomes, the five heavy metals could be determined effectively, of which the Cu content was the highest. Comparing with green medicinal standards (WM/T2-2004), we found that Cu content of medicinal materials from Henan province were already beyond the above standard, the other elements were permission. Moreover, S02content maintained around20mg· kg-1in sulfate-free decoction pieces, but which was up to above400mg·kg-1in all medicinal materials through sulfur fuming. After evaluating population based on WM/T2-2004, we found that P index was less than0.7in sulfate-free decoction pieces and was from0.76to1.29in sulfur fuming medicinal materials, results indicated that medicinal safety was at warning or slight pollution status as a whole. On the other hand, we also evaluated edible safety based on food standard (NY861-2004), the P index ranged07～5.0, most of investigated Dioscorea Rhizomes edible safety were moderate even severe pollution level.5. Comparative study on carbohydrate components of Dioscorea Rhizomes5.1Optimization of extraction process for oligosaccharides based on orthogonal test and detection The optimum extraction process was as follows:20volume folds of60%ethanol,80℃water bath, and extracting two times, each time1h. In light of the above method, most of oligosaccharide components could be extracted. UV determination indicated there were clear difference among different Dioscorea Rhizomes, the order of average content was showed, Dioscorea alata Rhizome(5.96%)> Dioscorea fordii Rhizome (4.83%)> Dioscorea oppostita Rhizome(4.29%)>Dioscorea persimilis Rhizomea(2.90%).5.2Optimization of process for polysaccharide based on response surface methodology and detectionAs another result, processing parameters were determined water-solid ratio of40, extraction under90℃water bath, and reflux time of1.5h respectively. Differences of polysaccharide average content among differ-ent Dioscorea Rhizomes were presented in the following way, Dioscorea alata Rhizome(13.18%)> Dioscorea persimilis Rhizomea(11.09%)> Dioscorea oppostita Rhizome(9.89%)>Dioscorea fordii Rhizome(8.92%).6. Study on determination of allantoin in Dioscorea Rhizomes by HPLC-DADSeparation and determination of allantoin were accessed by using a packed with5μm stationary phase HypersilODS2C18(200mmX4.6mm,5μm).The mobile phase consisted of methanol-water(10:90), of which pH was adjusted to range of4-9. The flow rate was0.5mL· min-1. Colum temperature and detection wavelength were set respectively at30℃and224nm. The linear range of the component was0.40μg～6.00μg, the regress equation:y=171.078x+16.712(R=0.9999), the average recovery of allantoin was100.32%(RSD=1.26%). Under the above conditions, allantoin in four species Dioscorea Rhizmoeswere respectively determined, of which Dioscorea alata Rhizome was the maxi-mum(1.03%), Dioscorea oppostita Rhizome were almost equivalent to Dioscorea fordii Rhizome(around0.90%), Dioscorea persimilis Rhizomea was the mini-mum (0.73%).7. Comparative study on saponin components in Dioscorea Rhizomes7.1Study on determination of total saponin in Dioscorea Rhizomes by UV spectrophotometryThe results showed that all investigated Dioscorea Rhizomes had relatively high saponin components. Among four species Dioscore Rhizomes, the average content of total sponin presented the following rule, Dioscorea oppostita Rhizome (2.255mg· g-1)> Dioscorea alata Rhizome (1.346mg· g-1)> Dioscorea persimilis Rhizomea(1.275mg· g-1)>Dioscorea fordii Rhizome(0.805mg·g-1). Moreover, the total sponin content in sulfate-free decoction pieces was always the maximum among different specifications Dioscorea Rhizomes7.2Study on determination of dioscin in Dioscorea Rhizomes by HPLC-DADThe determination was performed by a packed with5μm stationary phase HypersilODS2C18(200mm×4.6mm,5μm)with the mobile phase consisted of methanol-water (88:12). The flow rate wasl. OmL· min-1. Colum temperature and detection wavelength were set respectively at25℃and203nm. The method showed good linear relationship with the range of10.4μ g. mL-1～156.0μg. mL-1for dioscin (r=0.999), the regress equation:y=5.139X+16.815, the average recovery of dioscin was up to100.25%(RSD=1.32%). In light of above method, the average content of total dioscin presented the following relationship, Dioscorea oppostita Rhizome(814.76μg· g-1)> Dioscorea alata Rhizome (548.92μg· g-1)>Dioscorea persimilis Rhizomea(438.13μg· g-1)>Dioscorea fordii Rhizome (343.43μg· g-1). The dioscin content of sulfate-free decoction pieces presented also the highest than the other specifications.7.3Study on chromatographic fingerprint of saponin components in Dioscorea Rhizomes by HPTLCThe saponin components of Dioscorea Rhizomes were extracted methanol by means of ultrasonic. The separation was performed on pre-coated HPLTLC GF254silica-gel plate stationary phase with chloroform-methanol-water(13:7:2) as mobile phase, after pre-equilibrium30min under condition with relative temperature and humidity at25℃,35%respectively, the thin plate was developed by using10%sulfuric acid alcoholic solution. As a result, fingerprint HPTLC was obtained, which had good reproducibility and effective separation. The common pattern of twenty two Dioscorea Rhizomes consisted of8characteristic peaks, of which the similarity between Dioscorea oppostita Rhizome and common pattern presented the highest level (0.8323), the similarity between Dioscorea alata Rhizome and common pattern was0.6720, while the similarity between Dioscorea persimilis Rhizomea and common pattern was lowest with only0.5503level.Iconclusions]1. Study on genetic diversity in yam germplasm resources based on DNA molecular markers1.1ISSR markers and SRAP markers are powerful tools for revealing genetic diversity of yam resources. On the base of comprehensive results by combining ISSR markers and SRAP markers, yam germplasm resources presented highly genetic diversity level (PPb=94.12%) in China. But genetic diversity among populations contri-buted83.36%(Gst=0.8336)of the overall diversity, it is mainly ascribed to genetic variation among Dioscorea opposite, Dioscorea alata, Dioscorea fordii and Dioscorea persimili respectively, whereas within four yam species with relatively lower genetic diversity, of which Dioscorea opposite and Dioscorea alata have some genetic diversity. In a conclusion, we deem that asexual reproduction, directional selection with single character, cultivars exchange out of order, ect, are mainly factors reducing genetic diversity. It is very essential to enlarge the genetic base within yam species.1.2In this study, we also concluded that genetic distance was correlated with geographic distribution among different populations, it support the rule that samples living similar environment were clustered.After long time of cultivation, as a result, southern region(FJNP) has formed a new independent cultural population of Dioscorea opposite.1.3Moreover, ISSR markers and SRAP markers are also very effective technology to classify conventional yam cultivars, as a result, twenty one yam cultivars can be classified into four clusters corresponded to four yam species. The results by UPGMA cluster further support that all investigated yam germplasm resources was divided into Dioscorea opposite, Dioscorea alata, Dioscorea persimilis and Dioscorea fordii respectively, according with classic morphological taxonomy. ISSR markers and SRAP markers for identification and classification of numerous cultivars yam cultivars offered scientific basis.2. Study on genetic relationship in yam germplasm resources based on DNA sequence2.1The reconstructed phylogenetic trees based on rbcL, ITS sequences revealed that yam germplasm resources in China was monophyletic, of which identical ancestor was diplophyte belonging to Sect. Stenophora Uline. At systematic position, the genetic relationship was very close Dioscorea alata and Dioscorea fordii, and relatively isolated from the other species. Dioscorea alata was developed with preceding Dioscorea persimilis, it did not support that Dioscorea alata originated from crossing form between Dioscorea hamiltonii and Dioscorea persimilis. There were close genetic relationship among Dioscorea opposite, Dioscorea persimilis and Dioscorea japonica, of which Dioscorea japonica was priority evolutive, to agree with the view of Dioscorea opposite originating from Dioscorea japonica.2.2Moreover, the bases differences based on rbcL, ITS sequences in yam germplasm resources played an important role for identifying genotypic yams. The real correlation of environment and bases differences was also a reliable tool to study forming mechanism of geo-aurthentic crude drugs.3. Study on identification of Dioscorea Rhizomes3.1There were obvious differences of microscopic characters differences in tuber and leaves, it is available to distinguish different original Dioscorea Rhizomes.3.2The TLC identification method showed simple and highly specific, it can take objectively on differences among different original Dioscorea Rhizomes, this method is helpful supplement to Chinese Pharmacopoeia(edition2010).3.3According to processing FTIR fingerprint, we could rapidly identify different original Dioscorea Rhizomes.4. Heavy metal, SO2detection and quality safety assessment of Dioscorea RhizomesIn this study, sulfur fuming was deemed to an important reason of affecting medicinal safety, as a result, main Dioscorea Rhizomes with sulfur fuming was atwarning or slight pollution status. Refering to the food standard, main Dioscorea Rhizomes investigated are lack of safety insurance, with moderate even severe pollution level. So far, the medicinal materials standards in China is still relative loose, especially about SO2content, it was fail to guarantee the medicinal safety of Dioscorea Rhizomes.5. Comparative study on carbohydrate components of Dioscorea Rhizomes5.1In this study extracting process for oligosaccharides was stable and reproducible, it can provide scientific basis for development and utilization of oligosaccharide in Dioscorea Rhizomes. Different original Dioscorea Rhi-zomes have relative high oligosaccharides content, thus it was possible to evaluate the quality of Dioscorea Rhizomes by oligosaccharides.5.2According to the optimum Design-Expert, the process for polysaccharide was quite reliable, suitable and reproducible. Polysaccharide was one of the effective components in Dioscorea Rhizomes. Different originalRhizomes taking on significant differences in polysaccharide, of which content could be used to evaluate quality of Dioscorea Rhizomes.6. Study on determination of allantoin in Dioscorea Rhizomes by HPLC-DADThe HPLC-DAD detection method presented accurate, reliable and reproducible, it was an effective quality control method for Dioscorea Rhizomes. Allantoin was seen as an important effective component of Dioscorea Rhizomes, results revealed that Dioscorea alata Rhizome, Dioscorea fordii Rhizome and Dioscorea persimilis Rhizomea had relative rich allantoin, to some extent, it indicated they cloud be used for new resources of Dioscorea Rhizome. Sulfur fuming seen as traditional processing of crude drugs, it has greatly decreased the total allantoin accumulation on Dioscorea Rhizomes.7. Comparative study on saponin components in Dioscorea Rhizomes7.1The UV method was quite accurate, reproducible and stable. It could be used for the determination of total saponins of Dioscorea Rhizomes.There was obvious difference of total saponins in different original Dioscorea Rhiz-omes. Which indicated that selection for medicinal materials should be coping with differently. Sulfur fuming was also an unfavorable factor to dioscin accumulation of Dioscorea Rhizomes.7.2HPLC-DAD method of detecting dioscin was reliable, special, it could detect sensitively minim dioscin from different Dioscorea Rhizomes. As a consequence, it can provide scientific evidences for quality control Dioscorea Rhizomes.7.3The HPTLC fingerprint achieved cloud show visually evidences for distinguishing authentication and quality control of different original Dioscorea Rhizomes. The HPTLC fingerprint can also presented common pattern of all investigated medicinal materials, and it can reflect the whole differ-ences among medicinal materials, which is very consonant with synergistic action of multiple components with evaluating quality. In light of part difference among four original Dioscorea Rhizomes, that Dioscorea alata, Dioscorea fordii and Dioscorea persimilis was regarded new resources has been still questionable. Moreover, HPTLC scanning method for detecting dioscin is also effective to assess quality of Dioscorea Rhizomes.8. Main innovations in this study8.1DNA molecular markers were firstly applied to evaluate totally genetic diversity of yam germplasm resources in China, results proved scientific evidences for identification and classification of yam cultivars. On the other hand, we achieved primary rbcL, ITS sequences of fourteen conventional yam cultivars, and cleared genetic relationship among yam germplasm resources by constructing phylogenetic trees of yam resources.8.2Moreover, this study demonstrated systematically identification charact-ers, medicinal and edible safety, and quality differences based on multiple medicinal components respectively among different original Dioscorea Rhizomes. We also firstly obtained HPTLC of performing visually quality differences, and providing scientific basis for utilizing selectively Dioscorea Rhizomes. |
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