Production of Yam Tubers Using Seed Tubers from Vitroplants Regenerated from Aerial Stems in the Yam Species Dioscorea alata (L.) and Dioscorea cayenensis-rotundata (L. & P.) in Côte d’Ivoire

The aim of this study is to produce large quantities of yam tubers in the field from seed tubers derived from vitroplants regenerated from aerial stem cuttings and farmers’ tuber seeds. Seed tubers from ten yam cultivars, including five from Dioscorea alata (cDa083, cDa053, cDa115, cDa150 and cDa266) and five from Dioscorea cayenensis-rotundata (cDr015, cDr027, cDr150, cDr206 and cDr148) with distinct agro-morphological characteristics, were used as material. A completely randomized block design with 3 replications was used. In each block, all cultivars and seed types were represented. When put into cultivation, the tubers produced by the vitroplants all germinated and gave 100% healthy plants, compared with 86% to 100% healthy plants for the seed tubers produced by the farmers. Yields per hectare ranged from 10 to 25 tonnes for seed tubers produced by in vitro plants, and from 4 to 9 tons for seed tubers produced by farmers. Seed tubers from vitroplants can therefore be recommended to farmers as a solution to the problem of seed tuber unavailability.

First Report of a Successful Development of Yam Hybrids(Dioscorea alata L.)from Lyophilized and Long-Term Stored Pollens

Various biological constraints including erratic and asynchronous flowering between male and female plants hinder successful hybrid development and genetic gains in greater yam breeding programs.Therefore,pollen storage has gained much attention to facilitate artificial pollinations and increase the genetic gains.This 4-year study aimed at developing a practical long-term pollen storage technique for the successful development of yam hybrids.Fresh pollens were collected from two Dioscorea alata males,then lyophilized(two lyophilization treatments were applied),followed by storage at room temperature(24℃–25℃)for 12 months.Moreover,the lyophilized and stored pollens were tested for viability by crossing with four female varieties.Our results showed that lyophilization is effective for achieving viable pollens after 12 months of storage.Treatment 1(48 h drying)showed higher pollen germination and fertility rates than Treatment 2(72 h drying).Although we observed a reduction in viability of lyophilized pollens after 12 months of storage,we generated hybrid seedlings with success rates from 12%to 21%compared to 21%–31%when using fresh pollens.Paternity testing based on molecular genotyping confirmed the hybrid status of the obtained seedlings,which grew well in a greenhouse.Lyophilization is a practical approach for a long-term storage of greater yam pollen samples.This protocol will positively impact yam breeding programs particularly in developing countries.

The metabolic profiling of Chinese yam fermented by Saccharomyces boulardii and the biological activities of its ethanol extract in vitro

Chinese yam(Dioscorea opposita Thunb.),as one of the medicinal and edible homologous plants,is rich in various nutrients and functional factors.In this study,Chinese yam fermented by Saccharomyces boulardii was performed to investigate its bioactive components and metabolic profile.And then,the main bioactive components and biological activities of fermented Chinese yam ethanol extract(FCYE)were evaluated.Results showed that there were 49 up-regulated metabolites and 52 down-regulated metabolites in fermented Chinese yam compared to unfermented Chinese yam.Besides,corresponding metabolic pathways analysis initially revealed that the distribution of bioactive substances was concentrated on alcoholsoluble small molecular substances.Ulteriorly,the total polyphenol content and the total flavonoid content in FCYE were significantly increased,and the corresponding antioxidant and immunomodulatory activities in vitro were also significantly enhanced.Our study provided a new reference for the comprehensive utilization of Chinese yam and laid a theoretical foundation for the development and application of natural probiotic-fermented products.

Efficiency of Legumes in Increasing Yam Yield under Sandy Ferrasol in the Forest Zone of Southwestern Côte d’Ivoire

The cropping system is based on traditional farming in rural areas. In this way, yields of some food crops like yam are very low considering their high need for nutrients. The nutrient-rich land is under high land pressure as it is occupied by cash crops such as oil palm and rubber at the expense of food crops and soil fertility is declining. The study was conducted in Grand-Lahou to assess the effect of organic matter provided by legumes in increasing yam yield. The randomized complete block design included four (4) treatments: Arachis hypogaea + yam association (T1), Acacia mangium + yam association (T2), Arachis + Acacia mangium + yam association (T3) and pure yam crop (T0). The parameters measured were: the soil nutrients content, the rate of mineralization of organic matter through the C/N ratio as well as the yield of yam through different techniques that allowed the objective of the study to be achieved. It was noted a slight improvement of nitrogen and organic carbon in all treatments with a higher value recorded in the T2 treatment. The C/N ratio decreased to 12 in all treatments compared to the control, which reflects a normal decomposition of the organic matter. Treatment T1 increased yam yield (8.4 t/ha) in contrast to treatments T2 (4.1 t/ha) and T3 (2.8 t/ha). Legume-based treatments T2 and T3 were associated with a significant decrease in yam yield, resulting in losses of −46.34% to −25.09%, while treatment T1 resulted in a gain of 28.57%. As a result, the treatments involving legumes contributed to normalizing the organic matter content of the soil. The simultaneous association of these two legumes led to a decrease in yam production, contrary to the treatment associating only groundnut.

Effect of Purple Yam(Dioscorea alata L.) on Nutritional and Physiological Functions of Growing Rats

[Objective] This study was to explore the effect of purple yam on the nutritional and physiological functions of rats.[Method] Forty SD rats were randomly divided into four groups with ten rats in each group which were reared with artificial semisynthetic feed added with 10% steamed yam powder.The four groups,the casein（CK） group which was used as the control,the purple yam（PY） group,the Tiegun yam（TY） group and common Huai yam（HY） group,were supplied with feed of equal content of energy,protein and fat.The rats were pair-fed for 56 days to observe changes of relevant nutritional and physiological indices.[Result] There were no significant differences of body weight,food conversion rate and organ indices between rats in PY group and CK group.Mean corpuscular hemoglobin in PY group was significantly lower than that in CK group;hemoglobin showed no significant difference with that in CK group;eosnophils was lower than that in CK group.Low density lipoprotein-cholesterol,total cholesterol and atherogenic index in PY group were lower than that in the other three groups;anti-atherogenic index was the highest among the four groups,while showing no significant difference;triglyceride content was lower than that in CK group.Among the antioxidant indices,the activity of catalase and superoxide dismutase were higher than that in CK group,while malondialdehyde content was lower than that in CK group.[Conclusion] Purple yam showed the trend of reducing the content of blood glucose,total cholesterol,low density lipoprotein-cholesterol,triglyceride,malondialdehyde,and raising the activity of glutathione peroxidase,superoxide dismutase and catalase,thus having certain antioxidative function.

Chinese yam(Dioscorea opposita Thunb.) Notillage Ecological Cultivation Technique

For traditional cultivation of Chinese yam, it is necessary to dig a deep trench duringsowing and harvest, wasting labor and time, and Chinese yam requires good quality of cultivated land, causing serious impact on the development of yam industry due to the competition with food production. Yam no-tillage ecological cul- ture techniques, combined with advantage of yam directional tuberization, could en- able the cultivation of yam inlow-production field, barren hills and sloping field, forest land and other non-staple food land and thus could promote farmers＇ income as well as improving the ecological environment.

Identification of Polysaccharides from Chinese Yam(Dioscoreae opposite “Qi”) by Infrared Spectroscopy

In this study, the structure of polysaccharides from Chinese yam （Dioscoreae opposite ＂Qi＂） was analyzed and identified by infrared spectroscopy within an infrared spectral range of 400-4 000 cm^-1, Characteristic absorption peaks were observed at 840 cm^-1 （α-glucosidic bond）, 759.21 cm^-1 （xylose）, 830.87 cm^-1 （rhamnose）, 812.81 cm^-1, 876.60 cm^-1 （mannose） and 842.64 cm^-1 （arabinose） in infrared spectra of polysaccharides from D. opposite ＂Qi＂, indicating that D. opposite ＂Qi＂ polysaccharides exist mainly in the form of α-glucosidic bonds, including xylose, rhamnose, mannose and arabinose. The experimental results could provide the basis for quantitative analysis, development and application of polysaccharides from D. opposite ＂Qi＂.

Comprehensive characterization of yam tuber nutrition and medicinal quality of Dioscorea opposita and D.alata from different geographic groups in China

China is an important domestication center of yams,and two main yam species of Dioscorea opposita and D.alata are commonly cultivated in China.However,the differences of nutritional and medicinal characteristics between the two species and their subgroups remain unclear,which would greatly affect the resource conservation and commercial utilization of yams.In this study,typical yam resources including the species of D.opposita(wild and cultivated Ruichang yam from southern China,and Tiegun yam from northern China)and two landraces of D.alata(Longyan yam and Anyuan yam from southern China)were selected as materials.Nutritional traits and medicinal characteristics were determined and analyzed respectively.The results showed that there was no significant differences in the content of most nutrients between D.opposita and D.alata,but most cultivated Ruichang yam of D.opposita showed higher levels of starch,soluble sugar,sucrose,and ascorbate in tuber than that in yam from D.alata.Moreover,an UPLC-MS method was developed for identification and determination of medicinal characteristics in the two species.The results showed that allantoin can be detected in all selected samples.Cultivated Ruichang yam of D.opposita possessed the highest allantoin content among the tested materials,and was significantly different with that in Tiegun yam and D.alata.Dioscin was not detected in D.alata.Overall,there was little difference in nutritional composition between D.opposita and D.alata,but the medicinal quality of D.opposita was better than that of D.alata.Due to the outstanding comprehensive quality,the local variety of cultivated Ruichang yam can be further developed and utilized.

Isolation of Nine Microorganisms from Rotten <i>Dioscorea rotundata</i>(White Yam) and Antimicrobial Sensitivity Test with Five Plant Extracts

Five yam tuber varieties were investigated for microorganisms that cause yam tuber rot from five local government areas of Benue State, Nigeria, between the months of March 2014 to March 2015. Five fungi species: Aspergillus niger, Rhizopus stolonifera, Botryodiplodia theobromae, Fusarium oxysporum, Penicillium marnessei and four bacteria species: Serratia marcescens, Erwinia caro-tovora, Klebsiella oxytoca and Pseudomonas aeruginosa were consistently isolated. Pathogenicity test carried out confirmed these organisms as the pathological agent of the rot. Antimicrobial activity of five plant aqueous extracts: Terminalia catapa (common name fruit), Passiflora edulis (passion fruit), Daniella oliveri (Chiha-Tiv), Ceiba pentandra (Vambe-Tiv), Jatropha tanjorensis (Catholic plant) was carried out on the isolated microorganims and they showed varing degrees of inhibition, the aqueous extract from Passiflora edulis, Ceiba pentandra and Jatropha tanjorensis were able to inhibit all the fungi completely.

山药(Dioscorea opposita Thunb.)赤霉素合成酶基因DoGA20ox1的克隆及功能研究

GA20-氧化酶(GA20ox)是赤霉素生物合成的关键限速酶,控制活性赤霉素的合成。以大和长芋山药和毕克齐山药为试验材料,采用RT-PCR(Reverse Transcription-Polymerase Chain Reaction)技术克隆山药赤霉素合成酶基因(DoGA20ox1);分析该基因在2个品种山药不同器官及不同发育阶段的表达模式;构建瞬时、植物表达载体进行DoGA20ox1基因功能研究。结果表明:(1)DoGA20ox1基因的ORF长为1152 bp,编码383个氨基酸。氨基酸序列比对发现山药的DoGA20ox1与几内亚薯蓣的氨基酸序列相似度较高,都具有20G-Fe(Ⅱ)oxygenase保守结构域。(2)与cDNA对应的gDNA长度为1499 bp,包括3个内含子,4个外显子。(3)在烟草叶表皮细胞中瞬时表达表明,山药DoGA20ox1蛋白定位于质膜。(4)DoGA20ox1在毕克齐茎中及大和长芋叶中表达量最高,且在块茎的整个膨大期大和长芋的表达水平都显著高于毕克齐山药。(5)将DoGA20ox1基因转入烟草,检测结果表明该基因转录水平成功表达。本研究为深入探究DoGA20ox1生物学功能,解析山药块茎调控分子机制提供理论依据。

Polyphenol Oxidase Activity and Inhibition in White Yam （Dioscorea Rotundata. Var. Laasirin） Chips as African Fries for Human Consumption

Polyphenol oxidase, a bi-functional enzyme, has been implicated in enzymatic browning of yam and other tubers in a negative way. The objective of this present study was to examine the activity of polyphenol oxidase in Dioscorea rotundata. Var. laasirin and the efficiency of heat and chemical treatments in inhibiting this enzyme. Crude Polyphenol Oxidase （PPO） of Dioscorea rotundata.Var. Laasirin was isolated and the kinetics studied using the lineweaver-burk plot. The activity of the enzyme was evaluated using spectrophotomeric method. Yam PPO catalyzes oxidation of various substrates with catechol being the most readily oxidized substrate. The Michaelis-Menten constant （Km） and maximum reaction velocity （Vmax） for yam PPO were 0.00037 and 0.3125 respectively. Inhibition data showed that the enzyme had least activity （71.70） when blanched at 95℃ for 7 mins with chemical treatment involving a combination of 0.5% Sodium metabisulphite （Food grade） and 0.5% Ascorbic acid （Food grade）. The activity was highest （83.02） when it was blanched at 95 ℃ for 7 rains. This study has shown that it is possible to inhibit polyphenol oxidase activity in white yam using the chemical pretreatments and processing conditions described in this study for possible adoption in the production of packaged frozen yam chips by food industries.

Interspecific Crossing between Yam Species (Dioscorea rotundata and Dioscorea bulbifera) through in Vitro Ovule Culture

In the present study, in vitro ovule culture technique was used to obtain interspecific cross combination of Dioscorea rotundata ufenyi and Dioscorea bulbifera wild. Ten days after pollination, ovules were excised and cultured onto 1/2 strength Murashige and Skoog (MS) medium (Basal salt mixture + Vitamins) supplemented with 6% sucrose, 0.7% agar and plant growth hormones such as GA3, BAP, Picrolam and TDZ. Cultured ovules were transferred on 1/2 MS medium with 3% sucrose and 0.7% agar after three weeks. 40 days after pollination, germination was observed from 7 months cultured ovule between D. rotundata ufenyi x D. bulbifera wild. Hybridity of the regenerated plant was checked by flow cytometric method. A close relation was observed between the fluorescence intensity of the obtained progeny with one of the parents’ fluorescence. The observed progeny can be closely correlated with an apomictic tissue from an ovule parent of D. rotundata ufenyi. Plantlets derived from ovule culture were proliferated through in vitro shoot multiplication with hormonal concentration (0.5 mg/l BAP) supplemented with 1/2 strength MS medium. Obtained ovule culture derived in vitro plantlets were successfully hardened, acclimatized and transferred to the field, where they survived and grew normally. In plant breeding, interspecific crossing is very important technique, enabling the time needed to produce homozygous lines to be shortened as compared to the conventional plant breeding techniques.

Differential Rate of Dry Rot in <i>Dioscorea rotundata</i>(White Yam) along the Tuber Length Due to Rot Causing Fungi

The susceptibility of different regions in Dioscorea rotundata (white yam) tuber to rot infecting fungi was investigated. Isolation was made from the periphery of the rotted tuber tissues, followed by a pathogenicity test and identification of isolates. Three fungi associated with D. rotundata (white yam) were isolated;they include Penicillium oxalicum, Aspergillus niger and Rhizopus stolonifer. Each of the isolates from pure cultures were inoculated on the head, middle and tail regions of healthy yam tubers. The three fungi were found to be pathogenic at different rates at the head, middle and tail ends of the yam tuber respectively. The head region was less susceptible to the three fungi with the following rot depths (P. oxalicum 25 mma, A. niger 18.2 mma and R. stolenifer 12.7 mmb). Rot depth in the middle region was (P. oxalicum 15 mma, A. niger 10.6 mma and R. stolenifer 8.8 mmb). While the tail region of the yam tuber recorded rot depth of (P. oxalicum 32.0 mma, A. niger 26.4 mma and R. stolenifer 20.8 mmb) respectively. Generally, the tail region of D. rotundata was more susceptible to fungal attack and the rot recorded in the tail region was significantly different from rot at the middle and the head. It was recommended that yam tubers should be stacked with their head on the ground to reduce incidence of rotting in stock-piled yam tubers.

Improving the Size and Market Value of an Underutilised Yam （Dioscorea esculenta） in Ghana： Implications for Crop Breeding and Production Choices

Yam, Dioscorea esculenta which is a high value commodity is a threatened species in Ghana, due to several factors including neglect on the part of science, technology, research and development. Different doses of radiation were use to improve the size and market value of D. esculenta to promote it effective use and enhance effective conservation. We observed through repeated experiments that irradiation of yam planting material at 40 Gy gave the best results producing a M1 generation with a decreased number of tubers but with an increased tuber size per vine. Some yam characteristics are valued more than others, and prices vary across species, time, and market sites. Tuber weight exhibits an increasing marginal value and price per kilogram increases above an optimum size; therefore, yam producers and dealers derive additional reward from extra-large tubers. We conclude that, to effectively access and benefit from urban markets, producers should focus on the improved size and conical shaped-tubers, which are easy to process and meet the aesthetic qualities preferred by urban consumers. The implications for research on improved variety development to reduce poverty and for crop and resource management practices are drawn.

Effect of Synthetic Hormone Substitutes on Rooting of Vine Cuttings in Water Yam (Dioscorea alata L.)

The use of yam vine cuttings as propagules with appropriate synthetic rooting hormones such as IBA (Indole-Butyric Acid) and NAA (Naphthalene Acetic Acid) has previously been reported as successful but expensive. To source for cheaper alternatives, this study compared the effect of some natural and synthetic hormones on rooting of vine cuttings in two varieties of Dioscorea alata. Vine cuttings from three months old water yam varieties were treated separately with 1%, 3% and 5% concentrations of each of the following: neem leaf ash, coconut water, 2,4-D and IBA with water as control. Treated cuttings were planted in triplicates in polythene bags using the completely randomised design and watered once in two days for 49 days. Data collected on rooting percentage, number of roots per plant, mean root length, number and length of new vines were subjected to analysis of variance tests and the means separated using least significant difference tests. A 100% rooting was observed in vines treated with 1% or 3% coconut water and neem ash. These vines also generated significantly greater number of new vines (P < 0.05) compared to those from synthetic hormones. Vines treated with 5% neem produced the highest number of roots (145.33 ± 9.21;P < 0.001) while those treated with 3% neem produced the longest roots (45.3 ± 9.23 cm) followed by those treated with 3% coconut water (24.3 ± 3.48). The study reveals that neem leaf ash and coconut water are better root promoting agents for water yam vines than 2,4-D and IBA and could be tested further for use as natural hormonal substitutes to the synthetic hormones.

Changes in biochemical constituents and induction of early sprouting by triadimefon treatment in white yam(Dioscorea rotundata Poir.) tubers during storage

The ability of triadimefon （TDM）, a triazolic fungicide, to alter the biochemical constituents and thereby minimizing the days required for sprouting in white yam （Dioscorea rotundata Poir.） tubers during storage under （30±2） ℃ in the dark, was studied. TDM at 20 mg/L was given to tubers by dipping the tubers in treatment solution containing 20 mg/L TDM on 10, 25 and 40 d after storage （DAS）. Starch, sugars, protein, amino acid contents as well as protease and a-amylase activities were estimated on 15, 30 and 45 DAS from two physiological regions viz., apical and basal regions of the tubers. In normal conditions （control） sprouting occurred on 70 to 80 DAS. The starch content decreased, while protein, amino acid, sugar contents and protease and a-amylase activities were increased due to TDM treatment and led to early sprouting.

Effect of 24-Epibrassinolide on Growth of <i>in Vitro</i>Shoot Tips of Different Yam (<i>Dioscorea</i>Spp.) Species

In this work we compared the effect of the growth regulator content of the culture medium on the growth of in vitro shoot tips of five yam accessions belonging to four yam species (one Dioscorea alata, one D. rotundata, one D. cayenensis and two D. trifida). Medium S contained 0.6 μM benzyl adenine, 1.07 μM naphthalene acetic acid and 0.23 μM gibberellic acid while medium EBR contained 0.23 μM gibberellic acid and 0.1 μM 24-epibrassinolide. After 2 months of culture, oxidation level was significantly reduced on medium EBR compared to medium S for four of the five accessions tested. By contrast, medium EBR did not have any positive effect on shoot length since length of shoots produced after 2 months of culture on medium S and EBR were similar, except with accession 3-45T, for which shoot length was shorter on medium S compared to medium EBR. These results underline the potential of 24-epibrassinolide to reduce oxidation phenomena during in vitro culture and call for its utilization for regeneration of cryopreserved yam shoot tips, which is often impeded by oxidation phenomena.

Effect of Plant Growth Hormones and Liquid Fertilizer on Rooting and Tuberization of Yam (<i>Dioscorea rotundata</i>Poir.) Vine Cuttings

Vine cutting is an effective solution to solve the problem of seed availability in yam cultivation. This study was conducted to improve the recovery and rooting rate of vine cuttings of Dioscorea rotundata. Two-node cuttings from five (5)-month-old hybrid plants were grown in liquid media consisting of phytohormones (AIA3 and GA3) and liquid fertilizer (NPK 8-8-8) at different concentrations. Observations were made weekly from the 21st day after transplanting and focused on the survival rate of the cuttings, the number of roots emitted and the number of minitubers initiated. The results obtained showed a significant effect of the different growing media on the survival rate, rooting and production of minitubers. The best survival rates were obtained for cuttings grown in NPK (8-8-8) at 0.25% (100%) and AIA3 at 25 ppm (93.3%). The highest averages root number was recorded with growing media containing 0.25% NPK 8-8-8 (20.3) and 25 ppm AIA3 (17.7). Growing media with 0.25% NPK (8-8-8) and 25 ppm AIA3 provided the highest average numbers of minitubers initiated, respectively 5 and 4.6. Growing medium containing 0.25% NPK 8-8-8 has been identified as the one that allows better roots emission and minitubers production by yam vines cuttings.

Effect of Curing Treatments on Seven Key Farmers’ Yams (<i>Dioscorea</i>spp.) in Ghana

Curing of freshly harvested yams (Dioscorea spp.) is a process for wounded yams during harvest to heal. In this work the effectiveness of straw, polypropylene and jute sack on curing of seven key farmers’ yam varieties over a duration of 7, 14 and 21 days was studied. Seven key farmers’ yam varieties identified as Pona, Lariboko, Dente, Mutwumudoo, Serwah belonging to D. rotundata, Matches and Akaba belonging to D. alata were studied under different curing treatments. The percentage weight loss of yam tubers varied among the treatments over curing period. Curing under jute sack showed all yam varieties had weight losses less than 2.0%, within 7 days of curing. Five different varieties had weight loss less than 2.0% except Dente under the straw treatment. Mutwumudoo variety showed the highest water loss (8.4%) for polypropylene sheet and 6.9% for Lariboko in the control treatment. During 7 days curing the control and polypropylene treatment did not support yam curing. After 14 days of curing of tubers, similar tends were observed as in 7 days curing. After 14 days of curing under jute sack, percentage weight loss of the tubers ranges from 2.0% - 3.7%. In the straw treatment, the percentage weight loss ranges between 1.0% - 4.7% in all other varieties except Dente (D. rotundata) (8.2%). Polypropylene sheet treatment showed the highest percentage weight loss in Mutwumudoo variety (18.4%). A similar trend was observed for the yam tubers cured for 21days as percentage weight loss of tubers under jute sacks was 2.5 – 9.8%. Curing temperature and humidity ranged between 27&degC - 40&degC and 87% - 100% rh for yam tubers under the three different treatments of polypropylene, jute and straw. However, the control treatment recorded lower humidity of 60% - 80% rh. Curing material, duration, climatic conditions and yam varieties influenced curing and Serwah variety, which is a D. rotundata is the best bet yam variety to cure under jute sack for 7, 14 and 21 days of curing.

Formulation factors affecting the binding properties of Chinese yam(Dioscorea oppositifolia) and corn starches

Objective:The quantitative effects of formulation and processing variables affecting the binding properties of Chinese yam starch（Dioscorea oppositifolia） in chloroquine phosphate tablet formulations have been investigated in comparison with corn starch using a 23 factorial experimental design.Methods:Chinese yam starch,representing the "low" level,and corn starch,representing the "high" level were used as binders at concentrations of 2.5%w/w and 10%w/w in chloroquine phosphate tablet formulations.The mechanical properties of the tablets,measured by the tensile strength（T） and brittle fracture index（BFI） as well as the release properties measured by the disintegration time（DT） and dissolution time(t80- time for 80%drug release),were used as assessment parameters.Results:The ranking of the individual coefficient values for the formulations on T was D 】 N 】】C,on BFI was N 】 D 】】C,on DT was D 】 N 】 C and on t80 was C 】 N 】 D while the ranking of the interaction coefficient on T was N-D 】 C-D 】】 N-C,on BFI was N-D 】 N-C = C-D,on DT and t80 was N-C 】 N-D 】 C-D.Changing the binding agent from Chinese to corn starch,led to a decrease in T,DT and t80 but increase in BFI of the tablets.There were significant（P 【 0.001 ） interactions between the nature of binder,N and the other two variables,C and D.Conclusion:The result showed that Chinese yam possessed stronger binding capacity than corn starch and could be useful as an alternative binder when tablets with high mechanical strength with minimal problems of lamination,and slow release are required.