Wild Yam Species Research Articles

Wild edible yams from Madagascar: New insights into nutritional composition support their use for food security and conservation.

Yams (Dioscorea species) are an important food resource in Madagascar, where both cultivated winged yam (D. alata) and wild edible yams are consumed. However, there is limited knowledge on the nutrient composition of wild edible yams in Madagascar, and on how they compare with the cultivated winged yam. Therefore, in this study, nine wild edible yam species, one with two subspecies from Madagascar (D. bako, D. buckleyana, D. irodensis, D. maciba, D. orangeana, D. pteropoda, D. sambiranensis subsp. bardotiae and subsp. sambiranensis, D. seriflora, and Dioscorea species Ovy valiha), were analyzed for their nutrient composition, compared with cultivated D. alata. They include 6/6 of the most favored wild edible yam species in Madagascar. New nutrient composition data (protein, carbohydrate/starch, energy, lipid, β-carotene, and minerals) are presented for these nine wild edible yam species. The results show that they contain comparable levels of lipids and starch to D. alata, but none are better sources of protein than D. alata. The results show that D. irodensis contains a significantly higher β-carotene content when compared to all other edible yams analyzed, and that D. buckleyana, D. irodensis, and D. sambiranensis subsp. bardotiae have a higher calcium content than cultivated D. alata, while all nine wild edible yam species analyzed contain a higher iron content, compared to cultivated D. alata. The nutrient composition data presented could provide new incentives to conserve wild edible yams and inform on strategies to select Dioscorea species for sustainable cultivation and use, providing opportunities to enhance future food security in Madagascar.

Blending neglected and underutilised wild yam tubers from forest to functional food

The exploitation of neglected and underutilised wild yam species is an important livelihood strategy for tribal community along with providing food and nutritional security. In order to integrate them into developmental interventions, a region-specific assessment of their consumption, traditional processing, and optimal use by tribal groups is necessary. This study analysed the traditional use, consumption pattern and preferences of different wild yam species by tribal communities from 45 villages of Koraput (part of Eastern ghats of India). There are eight wild Dioscorea species have been used as food and medicine by the tribal people of this region. Among the wild species, D. pubera was the most preferred species with highest use vale (UV) of 1.76 followed by D. pentaphylla by the tribal communities. Further these two wild tubers were selected for making value-added products such as cookies and namkeen. From sensory evaluation, D. pubera cookies and namkeen showed better taste, crispiness, smell, colour and over all acceptability of a good score. In addition, these value-added products recorded higher protein, fiber, energy, antioxidants and nutritionally superior than conventional products. These functional foods from wild yam will helpful for mass consumption and will encourage the start-ups for enhancing economic growth of tribal people of the locality.

Physico-chemical compositions, nutraceutical properties, and starch-related techno-functional, thermal, and morphological characteristics of underutilized yam flour (Dioscorea spp.) from Odisha

High-yielding wild species of yam (Dioscorea spp.) play a vital role in the diet, nutritional, and economic stability of the tribal community. Lack of in-depth research provides scant information on the nutritional value and quality characteristics of tubers. In the present study, physicochemical, nutraceutical, antinutrients, structural, morphological, and thermal properties of lesser-known yam species: Dioscorea pentaphylla (five-leaf yam), Dioscorea bulbifera (bitter yam), Dioscorea hispida (intoxicating yam), and Dioscorea tomentosa (locally called ‘targai kanda’) were investigated. Total protein, fat, fiber, ash, carbohydrate, and metabolic energy of the investigated species are 5.05–8.79%, 0.33–1.01%, 3.53–14.15%, 3.30–5.31%, 62.60–78.26%, and 1241–149 kJ/100 g, respectively. Significant variations (P ≤ 0.05) were observed among the species for antioxidant, bioactive compounds, and physicochemical attributes, where Dioscorea tomentosa exhibited the highest antioxidant capacity. The starch and amylose content varied between 24.7–57.8% and 12.7–29%. X-ray diffractograms of D. pentaphylla and D. bulbifera displayed a B-type pattern, A-type starches in Dioscorea hispida, and CB–type starch for D. tomentosa. The FT-IR spectra confirmed the polysaccharide nature of the yam flours. The particle size ranged between 9.6 and 72.4 μm. The TG/DTG curves revealed that the yam flour could be subjected to cooking up to 180 °C without carbonization. The reported wild yam flours may have tremendous potential for industrial application. However, the study revealed that the presence of antinutrients might affect the mineral bioavailability, cause toxicity, and health hazards. Thus, this could be overcome by processing before safe consumption. The current study also recommended that these wild yam species are safe and can meet potential nutrition and food security through mainstream cultivation.

Environment factors influencing abundance and growth of wild yam in broadleaved forest, Tsirang District, Bhutan

Yams (Dioscorea) consist of approximately 600 species in the world. Yams are considered a staple food in Asia, tropical and subtropical regions. Genetic erosion and unsustainable harvesting practices are among the main problems associated with wild yam plants. This study was conducted with the objectives to enumerate wild yam species composition and environmental parameters affecting its growth and abundance. Systematic sampling of the study site was carried out based on different land aspects. Line transects were laid out in selected land aspects within the elevation range of 825 – 1935 m. Five plots in each transect with a 100 m plot interval comprising seven transects were laid out in the study area. Each plot was divided into sub-plot of 20 x 20 m, 5 x 5 m, and 1 x 1 m to enumerate trees, shrubs, and herbs respectively. Seven species of yams were found from the broadleaved forest and spearman correlation showed negative association of yam abundance with tree counts and canopy closure. The areas with higher density of trees had low count of yam abundance. Yam grows well in open canopy in lower altitudes comparing to high altitudes. Yam abundance was positively related with shrubs, herbs, soil moisture, soil organic matter, soil organic carbon, and nitrogen content. Analysis of Variance (ANOVA) showed significant difference of yam abundance in 7 different transects due to different ecological parameters influencing the abundance in different transects though transect being in a broadleaved forest.

Tracing the Supply Chain of Medicinal Wild Yam Species (Dioscorea spp.) in Cundinamarca, Colombia

Tracing the Supply Chain of Medicinal Wild Yam Species (Dioscoreaspp.) in Cundinamarca, Colombia. Wild yams (Dioscorea spp.) are widely distributed non-timber forest products that are traditionally used as medicine in Cundinamarca, Colombia, and represent a source of income for rural families in the region. The market for these native medicinal species has been growing due to their increasing popularity as a remedy for circulatory and blood problems; however, the supply and demand dynamics of this plant in the forest have not yet been documented. Through qualitative research methods, this study identifies the links and distribution of the wild yam supply chain in Cundinamarca and considers the implications for conservation and sustainability of the resource. Tuber collection was documented in forested areas in 14 municipalities in the Department of Cundinamarca. The tubers are destined for wholesale markets in Bogotá and are purchased by retailers from all over Cundinamarca, even those based in the municipalities from which the tubers were extracted. The collection, distribution, and consumption of Dioscorea species in Cundinamarca respond to growing demand and rely on extraction of the species directly from forest remnants within the Department; these could be at risk of overharvesting if management measures are not taken, or if participatory propagation programs that benefit harvesters and sellers are not implemented. This is the first study of the supply chain in an emerging new market for wild yams in Latin America. It highlights the dynamic, evolving nature of the medicinal plant trade from the local to the national scale, and beyond.

Patterns of transmission and horizontal gene transfer in the Dioscorea sansibarensis leaf symbiosis revealed by whole-genome sequencing

Leaves of the wild yam species Dioscorea sansibarensis display prominent forerunner or "drip" tips filled with extracellular bacteria of the species Orrella dioscoreae.1 This species of yam is native to Madagascar and tropical Africa and reproduces mainly asexually through aerial bulbils and underground tubers, which also contain a small population of O.dioscoreae.2,3 Despite apparent vertical transmission, the genome of O.dioscoreae does not show any of the hallmarks of genome erosion often found in hereditary symbionts (e.g., small genome size and accumulation of pseudogenes).4-6 We investigated here the range and distribution of leaf symbiosis between D.sansibarensis and O.dioscoreae using preserved leaf samples from herbarium collections that were originally collected from various locations in Africa. We recovered DNA from the extracellular symbiont in all samples, showing that the symbiosis is widespread throughout continental Africa and Madagascar. Despite the degraded nature of this DNA, we constructed 17 symbiont genomes using de novo methods without relying on a reference. Phylogenetic and genomic analyses revealed that horizontal transmission of symbionts and horizontal gene transfer have shaped the evolution of the symbiont. These mechanisms could help explain lack of signs of reductive genome evolution despite an obligate host-associated lifestyle. Furthermore, phylogenetic analysis of D.sansibarensis based on plastid genomes revealed a strong geographical clustering of samples and provided evidence that the symbiosis originated at least 13 mya, earlier than previously estimated.3.

Ethnobotanical survey of wild edible plants used by Baka people in southeastern Cameroon

BackgroundForest inhabitants worldwide, and indigenous people especially, have depended for generations on plants and animals harvested in these ecosystems. A number of Baka hunter-gatherer populations in south-eastern Cameroon became sedentarised in the 1950s, but still rely on hunting and gathering to meet their basic needs. The use of wild edible plants (WEP) by these communities remains largely undocumented. In this study, we record the diversity of WEP used by Baka people in dense rainforests in the Mintom region. The area still contains relatively undisturbed forest expanses, just south of the Dja Biosphere Reserve, one of the most important protected areas in the Congo Basin.MethodsWe conducted two ethnobotanical surveys in 2019 in four villages on the Mintom road. In the first survey, we interviewed a total of 73 individuals to determine WEP usage. In our second survey, we specifically quantified WEP harvested and consumed daily in a number of households over a 2-week period during the major rainy season, when use of forest products is highest. Specimens of all recorded plants were collected and identified at the National Herbarium of Cameroon.ResultsWe documented 88 plant species and 119 unique species/plant organ/recipes in 1519 different citations. A total of 61 genera and 43 families were noted. Excluding 14 unidentified wild yam species, 17 WEP species had not been reported in previous ethnobotanical surveys of the Baka. Our results showed that cultivated starchy plant foods make up a significant proportion of our study population’s daily nutritional intake.ConclusionsA high diversity of WEP is consumed by the studied Baka communities. The study area is likely to be significant in terms of WEP diversity since 18 out of the 30 “key” non-timber forest products, NTFP, in Cameroon were mentioned. Documentation of the use of WEP by indigenous communities is vital to ensure the continuity of traditional knowledge and future food security.

Natural antioxidant potential of selected underutilized wild yams (Dioscorea spp.) for health benefit.

Modern research is directed towards finding naturally-occurring antioxidants of plant origin for improving nutrition and health benefit. Wild yam species are used as indigenous food and medicine by various tribal groups of Koraput, India. However, detailed analysis of health promoting bioactive compounds and antioxidant properties are lacking. The present study aims to evaluate the flavonoid, total antioxidant capacity and in vitro antioxidant activity of different wild and cultivated Dioscorea species of Koraput. The extract of these tuber was screened for its potential antioxidant activities by various tests, such as DPPH, nitric oxide, superoxide and ABTS radical cation assay. The phenol, flavonoid and total antioxidant capacity of the samples were ranged from 2.19 to 9.62mgg-1 dry weight, 0.62-0.85mgg-1 dry weight and 1.63-5.59%, respectively. The IC50 values were 77.9-1164, 101.2-1031.6, 27.0-1022.6 and 47.1-690µgml-1 for DPPH, ABTS, superoxide and nitric oxide scavenging activity, respectively. Taken together, some wild yam species such as D. bulbifera, D. pubera and D. pentaphylla had significantly higher flavonoids content and antioxidant capacity along with the lower IC50 values than the standards in compared to the other species. The present studies confirmed that some wild yam tubers have superior potential for scavenging deleterious free radicals effectively. Results indicated that these wild yam species should be promoted as natural source of antioxidants.

Nutritional, anti-nutritional and physico-functional properties of wild edible yam (Dioscorea spp.) tubers from Koraput, India

Wild yams (Dioscorea spp.) make a significant contribution to the diets and economic welfare of tribal people of Koraput, India. However, there is a lack of information on the food quality of the tubers. The present study was carried out to evaluate the proximate, nutritional and anti-nutritional compositions as well as the physico-functional properties in 8 wild and one cultivated Dioscorea species. The proximate compositions, i.e., moisture, ash, fat, fiber, and crude protein content of yam tubers ranged from 54 to 83, 2.5 to 5.4, 0.56 to 2.0, 1 to 2.02 and 5.4–10.3% respectively. The mineral composition ranged from 31.4 to 89.4 mg 100 g−1 of sodium, 0.83–1.36 g 100 g−1 of potassium, with significant amounts of vitamin C and E. In addition, some wild species showed better nutritional and physico-functional parameters in comparison to the cultivated ones. Furthermore, the anti-nutritional compounds such as diosgenin, amylase- and trypsin-inhibitors were also significantly higher in some wild Dioscorea species. The biochemical characterization with multivariate data analysis led to a feasible classification of the usage of wild yam species. Taken together, the wild species, such as D. oppositifolia, D. hamiltonii and D. pubera showed better nutritional composition than the other yam species. The study also suggested that these wild yam species are a safe food source for local consumption and domestication, leading to potential improvement of food security.

‘From Elephant’s Foot … to Cortisone’: Boots Pure Drug Company and Dioscorea Sylvatica in South Africa, c. 1950–1963

ABSTRACTIn 1949 scientists in the United States announced the dramatic effects of a new drug, cortisone. They found that cortisone could be made cheaply from diosgenin, extracted from Mexican wild yam species, and began a global search for supplementary plants. By the early 1950s, South African botanists had identified the yam Dioscorea sylvatica, elephant’s foot, as promising. Boots, a major British pharmaceutical company, was keen to develop a source of diosgenin to manufacture corticosteroid medicines and started a factory in Johannesburg in 1955 to process D. sylvatica. Systematic extraction began in the eastern Transvaal and Natal. Our article focuses first on the global pharmaceutical context, as well as the identification and extraction of this plant. Second, we examine the conflicts that developed around harvesting, especially in Natal. Natal Parks Boards officers were uneasy about mass exploitation of a wild plant and attempted to enforce strict conditions. By 1960, they succeeded in terminating permits and Boots ceased production of South African diosgenin. This was a significant case for a fledgling provincial conservation authority. Third, we explore briefly issues of bioprospecting: the scientific exploitation of plant properties and whether this was a case of direct appropriation of local or indigenous knowledge.

Genetic variability and inter species relationship between wild and cultivated yams (Dioscorea spp.) from Koraput, India based on molecular and morphological markers.

Wild yams (Dioscorea spp.) are important tuber crops used both as vegetable and medicine by the tribal people of Koraput, India. There is deficiency of documented information on genetic structure and diversity of wild yams and its genetic assessment is necessary for crop improvement program. The present study assessed the level of genetic diversity of eight wild and one cultivated yam species of Koraput by using different morphological and molecular markers. Significant variation in different yield and morphological traits was observed among the studied yam species. The major morphological traits such as branch number, stem thickness, tuber depth, tuber length, number of tubers per plant and yield showed high genetic heritability accompanied with high genetic advance and major determinants of phenotypic diversity. Molecular profiling was carried out by taking five simple sequence repeat markers. A total of 10 polymorphic bands with an average of two were detected at the loci of the five markers across the nine yam species. Genetic similarity analysis revealed that some wild yam species such as D. oppositifolia, D. hamiltonii and D. pubera showed higher genetic similarity with cultivated (D. alata) species. The knowledge of the extent of genetic variations of wild yam species is important for planning of the genetic conservation and the utilization of this resource especially for genetic improvement.

Effect of ultrasonic dormancy breaking on seed germination and seedling growth of three wild yam species (Dioscorea spp.) from SW-Madagascar

In rural areas of Madagascar, wild yam species (Dioscorea spp.) serve as a food supplement and are therefore overexploited during food shortage periods. Domestication of wild species and promotion of their cultivation could reduce this pressure. To this end the regeneration abilities of seeds of three wild yam species from the Mahafaly region in SW-Madagascar exposed to pre-germination treatments were investigated. These consisted of chilling at 5 °C for 2 weeks, submersion in a water bath at 40 kHz for 10 min and 20 min, and a control whereby seeds were sown after soaking in running water for 1 h. Treatment effects on germination were species-specific (P < 0.001). For Dioscorea alatipes Burkill & H. Perrier (71%) and Dioscorea fandra H. Perrier (90%) germination was highest when seeds were exposed to 10 min of ultrasonic waves. For Dioscorea nako H. Perrier, however, highest germination was obtained when seeds were soaked in running water. Pre-chilling induced an early germination in D. fandra, which supports the importance of temperature in the germination of Dioscorea spp. from warm climates. Growth-enhancing effects of ultrasonic treatments were noticed at the initial stages of seedling development, such as seedling emergence. At the exposures tested no negative effect of ultrasound was noticed in any species. For the germplasm tested this study supported earlier evidence of ultrasonic treatment on seed germination and early seedling growth of Dioscorea spp. that could be helpful in the cultivation of wild yams, especially under drought conditions such as in SW Madagascar.

Adaptations and evolution of a heritable leaf nodule symbiosis between Dioscorea sansibarensis and Orrella dioscoreae.

Various plant species establish intimate symbioses with bacteria within their aerial organs. The bacteria are contained within nodules or glands often present in distinctive patterns on the leaves in what is commonly referred to as leaf nodule symbiosis. We describe here a highly specific symbiosis between a wild yam species from Madagascar, Dioscorea sansibarensis and bacteria of the species Orrella dioscoreae. Using whole-genome sequencing of plastids and bacteria from wild-collected samples, we show phylogenetic patterns consistent with a dominant vertical mode of transmission of the symbionts. Unique so far among leaf nodule symbioses, the bacteria can be cultured and are amenable to comparative transcriptomics, revealing a potential role in complementing the host's arsenal of secondary metabolites. We propose a recent establishment of a vertical mode of transmission in this symbiosis which, together with a large effective population size explains the cultivability and apparent lack of genome reductive evolution in O. dioscoreae. We leverage these unique features to reveal pathways and functions under positive selection in these specialized endophytes, highlighting the candidate mechanisms enabling a permanent association in the phyllosphere.

Evaluation of mineral bioavailability and heavy metal content in indigenous food plant wild yams (Dioscorea spp.) from Koraput, India.

Wild yam (Dioscorea spp.) tubers, an indigenous food makes a significant contribution to the diets of tribal people of Koraput, India. However, there is dearth of documented information of their mineral bioavailability and heavy metal content. To know their quality and safety concerns about their use, minerals and heavy metal concentrations were evaluated in eight wild and one cultivated yam species from Koraput. The samples were further investigated for their antinutrients to determine bioavailability of minerals. The majority of the wild yam tubers were rich in some of the essential minerals like calcium (18.08-74.79mg/100g), iron (11.15-28.61mg/100g), zinc (2.11-6.21mg/100g) and phosphorous (179-248mg/100g). The heavy metals concentration (mg/100g) ranged from: cobalt (1.06-1.98), nickel (0.30-0.89), chromium (2.10-4.53) and lead (0.11-0.93) among the studied yam species. These values were lower than the recommended tolerable levels proposed by WHO Expert Committee on Food Additives. Based on these results of molar ratio between phytate and Fe, Zn and Ca were below the suggested critical values indicating the bioavailability of Fe, Zn and Ca to be high. The study also suggests these wild yam species as the safe food sources for mass consumption and can be beneficial for health.

In vitro propagation of endemic wild edible yams of Western Ghats – the hotspot of global biodiversity and its conservation in India

North-Eastern Himalayas and Western Ghats are two hot spots of global biodiversity, showcasing the rich diversity in wild relatives of root and tuber crops, especially Dioscorea. Fifty different species of Dioscorea are reported from India, of which 44% are endemic and 16 of them occur in the southern Western Ghats. The Central Tuber Crops Research Institute (CTCRI) being the National Active Germplasm Site (NAGS) for tropical tuber crops addresses issues like collection/augmentation, characterization, evaluation, conservation, exchange and breeding work on yams. 5175 yam accessions consisting of 50 species including 231 accessions of wild Dioscorea collected from different agro-climatic regions of India are conserved here. The present investigation focuses on the in vitro propagation studies of eight endemic wild edible yam species, with distribution in the southern Western Ghats. These species are ethnically important as secondary staple among the local tribal population. Protocols were standardized for rapid clonal multiplication of these species through nodal segment culture, direct organogenesis as well as in vitro bulbil induction, which facilitated multiplication of true to type plants and dissemination of these valuable wild clonal materials to national programmes and their conservation. In vitro bulbil induction was achieved in the non-bulbil bearing species which is an excellent tool for conservation and international exchange programmes. Cytokinins (BAP/Kin/TDZ) alone or in combination proved best for direct de novo shoot organogenesis. Successful rooting and hardening with 85-94% survival of regenerants with underground tuber development enabled us to design effective management and conservation strategies for their sustainable utilization in crop improvement programmes.

Modelling the distribution of four Dioscorea species on the Mahafaly Plateau of south-western Madagascar using biotic and abiotic variables

Wild yam species (Dioscorea spp.) provide important supplementary food and thus contribute directly to the livelihood and well-being of local people in SW Madagascar. Given the ongoing exploitation of this resource, there is a necessity to identify and predict yam species distribution along environmental gradients to improve our understanding of sustainable management of this resource. Therefore, the aims of the current study were to identify predictors for the distribution of important wild yam species and to spatially predict their availability. To this end species abundance and environmental variables were collected in the field using a systematic sampling approach within a yams collection area of four villages (58 plots). A redundancy analysis (RDA) was conducted to investigate the relationship between wild yam species and 12 environmental variables. Species distribution models and species response curves were established for the most abundant wild yam species using nonparametric multiplicative regression (NPMR). These models were subsequently used in conjunction with geospatial data for predictive mapping. RDA depicted a clear pattern of species habitats with D. alatipes occurring in dry spiny forests on calcareous soils at remote places, while D. bemandry and D. fandra were found in forest habitats on sandy soils with high harvest intensities. The NPMR models explained 88% (D. alatipes), 82% (D. bemandry) and 37% (D. fandra) of the variation in species abundance. Sensitivity analysis indicated the importance of vegetation structure, human interventions, and soil characteristics in determining wild yam distribution. Predicted distribution maps showed that the population of wild yam is scarce and mostly located in restricted areas of open spiny forests and dry spiny forest thickets, where harvest intensity is high. This study highlights the need for long-term assessment and public awareness actions on yam harvest practices as well as the importance of anthropogenic factors for the distribution of yam as a key forest resource in SW Madagascar.

Effects of socio-economic household characteristics on traditional knowledge and usage of wild yams and medicinal plants in the Mahafaly region of south-western Madagascar.

BackgroundRural households in the Mahafaly region of semi-arid SW-Madagascar strongly depend on the exploitation of natural resources for their basic needs and income regeneration. An overuse of such resources threatens the natural environment and people’s livelihood. Our study focuses on the diversity and use of wild yams and medicinal plants.MethodsWe hypothesized that knowledge on the use of these resources highly depends on farmers’ socio-economic household characteristics. To test this hypothesis, an ethnobotanical survey was conducted based on semi-structured interviews recording socio-economic base data and information on local knowledge of medicinal and wild yam species. This was followed by field inventories compiling plant material for botanical identification.ResultsSix species of wild yam and a total of 214 medicinal plants from 68 families and 163 genera were identified. Cluster and discriminant analysis yielded two groups of households with different wealth status characterized by differences in livestock numbers, off-farm activities, agricultural land and harvests. A generalized linear model highlighted that economic factors significantly affect the collection of wild yams, whereas the use of medicinal plants depends to a higher degree on socio-cultural factors.ConclusionsWild yams play an important role in local food security in the Mahafaly region, especially for poor farmers, and medicinal plants are a primary source of health care for the majority of local people. Our results indicate the influence of socio-economic household characteristics on the use of forest products and its intensity, which should be considered in future management plans for local and regional forest conservation.

Phylogenetic relationship of wild and cultivated yam species (Dioscorea spp.) of India inferred from PCR–RFLP analysis of two cpDNA loci

The genus Dioscorea comprises approximately 600 species worldwide and about 50 in India. Dioscorea is economically very useful because of its food and medicinal value. Polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis was employed to study interspecific relationship between four cultivated and thirteen wild species belonging to seven taxonomical sections found in India. Restriction digestion analysis was performed for the amplified products of chloroplast DNA (cpDNA) loci psbA–trnH and trnL-F regions. Out of 17 restriction endonucleases tested, 5 endonucleases had restriction sites in psbA–trnH region and 6 endonucleases had restriction sites in trnL-F region. Digestion of amplified products with these restriction endonucleases showed 70 fragments of which 62 fragments (88 %) were polymorphic. Dendrogram obtained from UPGMA cluster analysis of two combined loci shows D. bulbifera of section Opsophyton to be closely placed with species of sect. Enantiophyllum. High similarity values obtained in this study between D. pentaphylla (sect. Botrysicyos) and D. esculenta (sect. Combilium) support their common origin. The average of genetic similarities between the ten species of Enantiophyllum section was 82.3 % showing their closeness. The present study suggests that the less studied New World species, D. floribunda (sect. Heterostemon) could have evolved from old world section, Lasiophyton. The principal component analysis (PCA) obtained from data of the two loci shows D. deltoidea of sect. Stenophora to be an outgroup. Interspecific genetic similarities showed D. deltoidea with low similarity values ranging from 27.5 to 37.5 % compared with other species and was, therefore, the most divergent species. D. deltoidea of section Stenophora shows distinctness because of its primitive characters. This study, therefore, establishes species relationships between wild and cultivated yams of India which would help in yam crop improvement programmes.

Technical Sheet of Some Wild Yam (Dioscorea) Species Starch Functional Properties

ABSTRACT: The starches extracted from the tuber of some wild yam species (D, praehensilis, D hirtiflora. D.bulbifera (bulbil and tuber) D. multifera, D burkilliana, D. dumetorum and D. togoensis) picked in the Ivory Coast forest zone, have been studied according to their functional properties which included: iodine absorption spectrum, viscosity, swelling and solubility, syneresis and clarity. These studies showed a wide variety of starches from one species to another at the morphological level.

Classification of Some Wild Yam Species Tubers of Ivory Coast Forest Zone

The tubers of some wild yam species (eight) found in the Ivory Coast forest were collected and their classification according to their nutrients and antinutritional factors was made by principal component analysis (PCA). The principal component analysis (PCA)of individuals,constituted by the yam species ,according to nutrients considered as the variables, showed two principal axes of correlation F1 and F2 .The percentages of variablesdispersionaround the principal axes F1 and F2 were equal to 72.86% and 20.24% respectively. Theindividuals projected on the principal axes F1 and F2 grouped into four classes around the axes. Around the axis F1 (72.26%): The class gathering the tubers of wild yam s peciesD. minutiflora;D. will hirtiflora and D. bulbiferabulbil which contained more Moisture and the class gathering the tubers of wild yam species D. burkilliana;D.bulbiferatuber;D. dumetorum;D. praehensilisand D. mangenotiana which had the highest Energy Value. Around the axis F2 (20.24%): The class gathering the tubers of wild yam speciesD. burkilliana ;D. bulbiferatuber;D. dumetorum and D. praehensiliswhich contained more Soluble carbohydrates and the class gathering the tubers of wild yam speciesD. minutiflora; D. hirtiflora ; D. bulbiferabulbil andD. mangenotiana which contained moreash. The principal component analysis(PCA) of individuals, const ituted by wild yam species ,according to their Antinutritional factors