Yam Dioscorea Research Articles

Sensitivity of antioxidant status of plant cells to furostanol glycosides

The present paper reports that in vitro plant objects (test tube plants and cell cultures), when subjected to furostanol glycosides (FG), underwent nonspecific reactions related to antioxidant status—decrease in peroxidation of lipids (POL) and increase in guaiacol-dependent peroxidase activity. The level of superoxide increased as early as after 5 min from contact with yam (Dioscorea deltoidea Wall) cells with FG. In this case, changes in POL processes and in activities of peroxidase and aldehyde-disposing emzymes were also observed. Upon a short-term cell exposure to FG, the levels of the primary POL products (conjugated dienes) increased, and that of the secondary POL products decreased compared to the control. These events were preceded by a rise in SOD activity and in an antioxidant activity of peroxidase along with a concurrent decrease in its oxidase (prooxidant) activity. The elevated activities of aldehyde-disposing enzymes aldehyde dehydrogenase and aldehyde reductase favored the reduction in the content of the secondary products of POL. Upon a long contact of FG with cells, the effect of FG was seen only at the initial and final phases of the culture growth cycle. Namely, FG diminished the POL level at the exponential growth phase and at the end of the cell degradation phase but had no effect at the stationary phase and the onset of the degradation phase. Therefore, the treatment with FG retarded the cell culture degradation and made the fall in cell viability not so dramatic by the end of the growth cycle. Actually, by the end of the degradation phase, the viability diminished down to 40% in the control but remained at 70% in the FG-treated counterpart.

Effect of phosphoric acid treatment on physicochemical, functional, and structural properties of starch extracted from yam (Dioscorea rotundata)

ABSTRACTThis work was designed to elucidate selected physicochemical, functional, and structural properties of native and modified yam (Dioscorea rotundata) starch. The isolated starch was chemically modified using 5, 10, 15, 20, and 25% phosphoric acid solution at 50°C for 1 h, and yield, swelling power, gelation, water holding capacity, paste clarity, blue value, and amylose and amylopectin content of the native and modified yam starch were determined. Structural changes in the native and starch modified with 25% phosphoric acid were evaluated using Fourier transform infrared spectroscopy and optical microscopy. The result showed that the yield, swelling power, water holding capacity, paste clarity, blue value and amylose and amylopectin content of native yam starch was 33.38% (217 g), 3.84 g/g, 1.0 v/g, 10%, 0.52 and 25.96, respectively, whereas gelation study of the native and modified starch indicated that native starch was viscous and modified starch firm. However, yield, swelling power, water holding capacity, paste clarity, blue value, and amylose content of modified yam starch reduced in a dose dependent manner with phosphoric acid. The reduction in the values of the various functional properties could be associated with the effect of phosphoric acid on the starch granular structure. The result of Fourier transform infrared spectroscopy and optical microscopy revealed that the yam starch was modified by phosphoric acid with changes in functional groups spectra such as –OH stretch (3177 cm−1), H2O absorbed (1644 cm−1) (amorphous region), C-H stretch (2923 cm−1), CH2O (1253 cm−1), and C-O-C (1078 cm−1) when compared to native starch. The morphology of native and modified yam starch granules ranged from oval to eliptical. However, modified starch granules were rough in surface. In conclusion, the characterized physicochemical and functional properties and structure exhibited by native and modified yam starch indicated that, yam could be a cheap and valuable source of starch for industrial application.

Fostering entrepreneurship to help provide a sustainable clean seed yam production system in flood prone areas of Idah, Kogi State, Nigeria

ABSTRACTThe article outlines some of the findings and insights achieved from efforts to establish a sustainable seed yam (Dioscorea rotundata) supply system in Idah, Kogi State, Nigeria. The activity was part of a project entitled “Yam Improvement for Income and Food Security in West Africa,” spanning from 2012 to 2016, and this article covers the results of a novel and ambitious intervention designed to establish seed yam entrepreneurs as part of a wider initiative to establish a sustainable seed yam value chain in an area where none had previously existed. Seed yam production by the entrepreneurs was based on the adapted yam minisett technique (AYMT) and results between 2013 and 2015 suggest that the agronomic performance of AYMT under “farmer-managed” conditions was good, with reasonable yields of yam and an average weight (0.8 kg) in the required range for grade 1 seed yams. The entrepreneurs achieved a good economic return (gross margin) and this translated into a return on investment of around 400–600%. However, for the seed yam system to be sustainable in the Idah area, there is a need to establish a value chain that links traders with growers.

Physicochemical Properties and Starch Digestibility of Autoclaved-Cooled Water Yam (Dioscorea alata L.) Flour

Water yam (Dioscorea alata L.) is suitable for resistant starch high flour because of its high amylose content. The purple, yellow, and white water yams were treated by autoclaving and cooling with one, two, and three cycles to obtain resistant starch. Water yam tubers were cooked in an autoclave for 15 min, and then cooled prior to drying. Autoclaving–cooling of water yams decreased protein, fat, dietary fiber, water soluble polysaccharide, dioscorin, and diosgenin but increased amylose and sugar. The treatments significantly raised resistant starch and reduced in vitro starch digestibility that depended on water yam types, and affected starch granule morphology.

Physicochemical and Organoleptic Properties of Dried Synbiotics Yoghurt from Lesser Yam Tubers (DioscoreaesculentaL.)

There are many variations of Yam ( Dioscorea spp.) which spread out in the world including Indonesia. Those variations could be categorized based on their shape, size, colour, and flavour of their tuber. The genus of Dioscorea spp. has more than 600 species, such as Dioscorea hispida , Dioscorea esculenta (lesser yam), Discorea bulbifera , Dioscorea alata (purple yam), Dioscorea opposita (white yam), Dioscorea villosa (yellow yam), Dioscorea altassima , and Dioscorea elephantipes. At the present, the utilization of yam tubers is seen to be limited. The purpose of the research was to evaluate the properties/characteristics of dried synbiotics yoghurt from lesser yam tubers. The treatment on this study was performed by the number of substitution of lesser yam tubers and the fermentation time. The results show that the dried synbiotics yoghurt that most preferred by consumers was G 2 F 3 (lesser yam 40% and fermentation time 22 hours) with an average value 3.65. It is followed by the total LAB (lactic acid bacteria) 8,15 log cfu/g, pH 4.27, total lactic acid 1.02%, yield of dried synbiotic yoghurt 32.30%, and total soluble protein 4.53%.

Putative endophytic fungi from taro (Colocasia Esculenta), greater yam (Dioscorea Alata) and elephant foot yam (Amorphophallus Paeoniifolius)

Endophytic microorganisms which remain asymptomatically inside plants have the potential to be used widely in agricultural field and valuable for agriculture as a tool to improve crop performance. Tuber crops are the second most important group of crop plants and among them tropical root and tuber crops which include cassava, sweet potato, yams and aroids, are essential as staple food and are utmost important for world food security. Research on these crops has been neglected and regarding endophytic colonisation, some of these tuber crops have been examined. Healthy asymptomatic leaves of three tropical tuber crops viz. taro (Colocasia esculenta), greater yam (Dioscorea alata) and elephant foot yam (Amorphophallus paeoniifolius) were inoculated on potato dextrose agar media to detect endophytic colonisation. Total six different putative endophytic fungi were isolated from these crops which were found to be non-sporulating when observed under microscope. Further works are being carried out for the identification and utilisation of these organisms in tuber crops improvement. This communication is to report the presence of putative endophytic fungi in taro, yam and elephant foot yam for the first time.

Effects of Calcium Fertilization on the Susceptibility of Dioscorea Species to the Yam Storage Pathogens Aspergillus Niger van Tiegh and Botryodiplodia Theobromae Pat

The effects of soil amendment with basal dose of nitrogen (60 kg ha- 1), phosphorus (30 kg ha-1) and potassium (75 kg ha-1) for Yams Dioscorea species in South West Nigeria and calcium carbonate were assessed on yield and susceptibility to two storage rot pathogens, in Dioscorea alata TDa 92-2, D. rotundata TDr 131 and D. esculenta TDe 89-1. The study site at the Teaching and Research Farms of the Federal University of Agriculture, Abeokuta, had been monocropped to yams without fertilizer for three years before the study. A 3 by 5 factorial desgn, with the Dioscorea species as main plots and 0 kg ha-1, 2 kg ha-1, 4 kg ha-1, 6 kg ha-1 and 8 kg ha-1 calcium carbonate as subplot treatments, was used in each of two years. Aspergillus niger van Tiegh. and Botryodiplodia theobromae Pat. were the two yam storage pathogens used. Pre-planting soil analysis in the two years revealed calcium, magnesium and potassium below the critical levels required for Dioscorea species in South Western Nigeria. Calcium fertilizer enhanced resistance and reduced weight loss in yam ‘’sections;’’ of D. rotundata TDr 131 and Dioscorea alata TDa 92-2 to the pathogens after long-terms storage of over four months in both years. Response of whole tubers incubated for an additional (after the four months) period of ten weeks and six weeks in years one and two respectively, was not significantiy (P=0.05) different from the control. Futher work to determine endogenous or physiological reasons for this is necessary. D. esculenta TDe 89-1 was more susceptible to the rot pathogens than the other two species. D. esculenta TDe 89-1 was also not significantly different in infection or weight loss than the control in the two years, necessitating a need to ascertain optimum fertilizer placement methods for this species in Nigeria. There were no differences in tuber number or tuber weight per plant at the treatment levels.

Response of yams exposed to different sources and doses of nitrogen fertilizers in the State of Maranhão, Brazil

This study was carried out at the State University of Maranhão, São Luís, Brazil from January to November 2012. We assessed the behavior of the yam Dioscorea cayenensis ‘Da Costa’, fertilized with different rates and sources of nitrogen (N). The experimental design was randomized, with treatments in a 6 × 2 factorial design. The factors were represented by six rates of N fertilization (0, 50, 100, 150, 200, and 250 kg·ha-1) and two sources (ammonium sulfate and urea) by using four replicates. We evaluated the mean mass, commercial root yield, leaf N content, starch content in the tubers, and percentage of tubers with symptoms of nematode infection (dry and thick skins). The maximum values for the mean masses of commercial tubers were 2.5 and 1.9 kg with doses of 130 and 160 kg of N ha-1 from ammonium sulfate and urea, respectively. Doses of 130 and 154.3 kg of N ha-1 produced the maximum yields of commercial tubers of 19.7 and 14.9 t·ha-1 with ammonium sulfate and urea fertilization, respectively. The maximum levels of foliar N by using urea and ammonium sulfate were 36.5 and 29.3 g·kg-1, respectively, at a dosage of 250 kg·ha-1. The maximum starch contents of 25.7 and 28.3 % were obtained at doses of 114 and 116 kg of N ha-1 of ammonium sulfate and urea, respectively. The percentage of tubers infected with nematodes was 10% when the N source was urea and 15.6% when the source was ammonium sulfate, both at a dosage of 250 kg·ha-1.

EFFECT OF FUSARIUM NYGAMAI INFECTION ON THE CHEMICAL COMPOSITION OF FLOUR FROM TWO YAM VARIETIES

Yams (Dioscorea spp) are among the oldest food crops. It is estimated that after six months of storage up to 56% of the crop is lost to rot. In Nigeria, fresh yam tubers are used for production of Elubo (yam flour) for preparation of amala, as it is called among the Yoruba in Western Nigeria, and akwunaji in the east of the River Niger. Many researchershave emphasized the importance of microbial rotting in causing storage losses. This study evaluated the effect of yam rot on the nutritional values of Fusarium infected yam tubers.Tubers from two yam (Dioscorea rotundata Poir.)varieties-Nwopoko and TDr95/19177-were infected with Fusarium nygamai pure culture and stored for 12 weeks, after which the tubers were used to produce yam flour and were analyzed for their nutrient composition comprising: dry matter/ moisture content, ash, total sugar, starch, amylose, vitamin C, protein and tannins. Wholesome yams of the same varieties were also used to produce yam flour and equally evaluated for the same nutrients. Infection with Fusariumnygamai led to a significant reduction (p<0.05) in the nutrient composition of the infected yam flour compared with those ofwholesome samples. Vitamin C content reduced from 41.10 to 27.26 (mg/100g) in variety Nwopoko and 36.30 to 30.53 (mg/100g); in variety TDr95/19177. Corresponding values for protein content was from 5.05 to 4.60% and 4.93 to 4.62%; Ash Content from 1.32 to 1.30% and 1.36 to 1.24%; Total Sugar Content from 5.34 to 5.20% and 5.21 to 5.02%; Starch 78.71 to 77.61 and 89.28 to 81.53%; Amylose from 29.95 to 28.87% and 30.01 to 27.95%. However, an increase in the tannin content – (1.84 and 1.94 mg/g) as against (0.31 and 0.26 mg/g) in Nwopoko and TDr 95/19177 varieties respectively was observed. The increase in the tannin content implies an increase in the antinutrient composition. The tendency to produce Elubo used for preparation of amala with rotten yam (possibly Fusarium infected) should be discouraged.

Yam storage protein dioscorins modulate cytokine gene expression in BALB/c and C57BL/6 lymphocytes

This study aimed to evaluate the effects of dioscorins isolated from 2 yam species, Dioscorea alata (Da-dioscorins) and Dioscorea japonica (Dj-dioscorins), on mouse immune activities. Results from cytokine array indicated that Dj-dioscorins increased the production of tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-3, IL-6, IL-10, IL-12p40, IL-13, monocyte chemoattractant protein (MCP)-1, regulated on activation, normal T cell expressed and secreted (RANTES), and granulocyte colony-stimulating factor (GCSF) in the spleen cells of BALB/c mice. In RAW264.7 macrophage, Da-dioscorins upregulated the expression of TNF-α, IL-1β, IL-6, IL-10, RANTES, MCP-1, and GCSF genes to a greater extent than Dj-dioscorins did. TNF-α, IL-1β, IL-6, IL-10, and RANTES gene expression was higher in spleen cells than in bone marrow and thymus cells in Da-dioscorin- or Dj-dioscorin-treated BALB/c and C57BL/6. Overall, our results suggest that dioscorins exert distinct immunomodulatory effects on mouse immune cells, and that different mouse strains respond differently to dioscorins.

Cassava (Manihot esculenta Crantz) and Yam (Dioscorea spp.) Crops and Their Derived Foodstuffs: Safety, Security and Nutritional Value

Cassava (Manihot esculenta Crantz) and yam (Dioscorea spp.) are tropical crops consumed by ca. 2 billion people and represent the main source of carbohydrate and energy for the approximately 700 million people living in the tropical and sub-tropical areas. They are a guarantee of food security for developing countries. The production of these crops and the transformation into food-derived commodities is increasing, it represents a profitable business and farmers generate substantial income from their market. However, there are some important concerns related to the food safety and food security. The high post-harvest losses, mainly for yam, the contamination by endogenous toxic compounds, mainly for cassava, and the contamination by external agents (such as micotoxins, pesticides, and heavy metal) represent a depletion of economic value and income. The loss in the raw crops or the impossibility to market the derived foodstuffs, due to incompliance with food regulations, can seriously limit all yam tubers and the cassava roots processors, from farmers to household, from small-medium to large enterprises. One of the greatest challenges to overcome those concerns is the transformation of traditional or indigenous processing methods into modern industrial operations, from the crop storage to the adequate package of each derived foodstuff.

CLEANING ROOT CROP PROPAGULES TO INCREASE FARM PRODUCTIVITY AND SUPPORT GAP SYSTEM

The use of clean planting materials is a good agricultural practice to improve crop yield, quality and food safety. This is of particular importance for asexually propagated crops such as root crops. Sweetpotato (Ipomoea batatas L.), cassava (Manihot esculenta Crantz) and yam (Dioscorea alata L.) are usually propagated using vine cuttings, stem cuttings and tuber slices, respectively; as such, pathogen load accumulates and is passed on from one generation to the next. The systemic presence of pathogens within the plant has no visible symptom except for depressed vigor and yield which is usually misdiagnosed resulting in unnecessary use of additional farm inputs such as pesticides and fertilizers. In an attempt to produce clean planting materials, several ex vitro and in vitro methods were tested; among these methods, the serial application of greenhouse preconditioning, thermotherapy, and meristem culture was established to be the best technique. Virus indexing tests confirmed the disease-free nature of the plantlets which were then mass propagated for field evaluation in comparison to conventional propagules. Plants produced from clean propagules remarkably outperformed those from conventional propagules as they had better field performance and higher yields than the latter. It is strongly recommended that Good Agricultural Practice (GAP) for root crops and other asexually propagated crops should integrate the use of clean planting materials.

Climate change impact and potential adaptation strategies under alternate climate scenarios for yam production in the sub-humid savannah zone of West Africa

Globally, yam (Dioscorea spp.) is the fifth most important root crop after sweet potatoes (Ipomoea batatas L.) and the second most important crop in Africa in terms of production after cassava (Manihot esculenta L.) and has long been vital to food security in sub-Saharan Africa (SSA). Climate change is expected to have its most severe impact on crops in food insecure regions, yet very little is known about impact of climate change on yam productivity. Therefore, we try estimating the effect of climate change on the yam (variety: Florido) yield and evaluating different adaptation strategies to mitigate its effect. Three regional climate models REgional MOdel (REMO), Swedish Meteorological and Hydrological Institute Regional Climate Model (SMHIRCA), and Hadley Regional Model (HADRM3P) were coupled to a crop growth simulation model namely Environmental Policy Integrated Climate (EPIC) version 3060 to simulate current and future yam yields in the Upper Oueme basin (Benin Republic). For the future, substantial yield decreases were estimated varying according to the climate scenario. We explored the advantages of specific adaptation strategies suggesting that changing sowing date may be ineffective in counteracting adverse climatic effects. Late maturing cultivars could be effective in offsetting the adverse impacts. Whereas, by coupling irrigation and fertilizer application with late maturing cultivars, highest increase in the yam productivity could be realized which accounted up to 49 % depending upon the projection of the scenarios analyzed.

International Research Journal of Agriculture and Soil Science

Low multiplication ratio of yam and scarcity of planting materials are major constraints militating against sustainable yam production. In order to evaluate the behavior of the four various types of seeds of two species of yams Dioscorea cayenensis and Dioscorea rotundata, cultivated on the experimental ground of the Higher National Institute of Agronomy and Biotechnology (INSAB), a test was realized in a randomized complete block design with six replications. The samples were cut and three levels of each tuber were used: proximal, medial and distal parts of the tuber. The fragments of tuber and the whole tuber represent the various types of seed used in this work. The results showed significant (P<0.05) differences in number of plants emerged and time of emergence in a mixture of 40% soil and 60% sand three months and half after planting. For all species, the proximal parts sprouted earlier than the medium parts and then the distal parts. The fragmentation of tubers in three (3) parts can show the existence of a gradient along the tuber in its potential for sprouting and growth. There was a highly significant (P<0.05) difference between yield performances after nine (9) months of culture. This technique improves the production of tubers in both species.

Nutrient elements distribution in cultivated and uncultivated soils and sediments of surrounding streams of Okai and Kwanta in Aabiriba, Abia state, Southeastern Nigeria

A study was conducted in 2009 to investigate the distribution of nutrient elements in cultivated and uncultivated soils, and sediments of surrounding Okai and Kwanta streams in Abiriba, Abia State of Southeastern Nigeria with the intention to determine the impact of agricultural practices on the water quality of these streams. The Okai stream was surrounded by a three-year old fallow land dominated by oil palm ( Elaeis guineensis ), raphia palm ( Raphia spp), cocoyam (Colocasia esculentus ), avocado tree ( Persea Americana ), shrubs (mainly Sponelias munibin ) and sparsely distributed grasses. The upland farm close to this stream was grown to cassava ( Manihot esculenta ), pepper ( Capsicum spp), and yam ( Dioscorea spp). The Kwanta stream was located near a six-year old fallow land with a scanty bush predominantly composed of bamboo tree ( Bambusa spp), oil palm ( Elaeis guineensis ), shrubs and grasses. The upland around this stream was a cultivated cassava farm. Crop rotation was the only means of replenishing used nutrients. Three sediment samples were collected at random at three points within the edges of each stream, bringing the total number of sediment sample to six. Three soil samples were collected randomly at two depths (0-20cm and 20-40cm) within the cultivated as well as the uncultivated farm, giving a total of 24 soil samples. Physical (particle size distribution) and selected chemical laboratory analyses were carried out on the soil and sediment samples. As the results showed, though both soils were generally low in nutrient elements, the Kwanta soil was a little more fertile than that of Okai. The cultivated soils were richer chemically than the uncultivated soils at both Okai and Kwanta sites. The nutrient load of Kwanta stream was higher than that of Okai stream, and this translated into more eutrophication in the former than in the latter. The sediments from the two streams were sandy, while the cultivated and uncultivated soils from the two study locations were loamy sand in texture. The soils from the sites varied (P < 0.05) significantly in Na and CEC values, while the sediments from the two streams showed significant difference (P < 0.05) in K and H contents. The soils of Okai and Kwanta farms are similar to the sediments of their respective streams in terms of chemical properties; this implies that the agricultural activities in the study area exerted some influence on the sediment and water quality of nearby streams

Antiglycative and Antioxidative Properties of Ethyl Acetate Fraction of Chinese Purple Yam (&lt;i&gt;Dioscorea alata&lt;/i&gt; L.) Extracts

Antiglycative and Antioxidative Properties of Ethyl Acetate Fraction of Chinese Purple Yam (&lt;i&gt;Dioscorea alata&lt;/i&gt; L.) Extracts

Quality Characteristics of Yackwa made with Yam (Dioscorea batatas Decne) Powder

Quality Characteristics of Yackwa made with Yam (Dioscorea batatas Decne) Powder

Quality Characteristics of Yackwa made with Yam (Dioscorea batatas Decne) Powder

Quality Characteristics of Yackwa made with Yam (Dioscorea batatas Decne) Powder

Evaluation of cross protection by an attenuated strain of Chinese yam necrotic mosaic virus in Chinese yam

We evaluated the cross protection effectiveness of an attenuated strain of the Chinese yam necrotic mosaic virus (CYNMV), KM3, in the field. Chinese yam (Dioscorea opposita) cv. Nagaimo plants infected with KM3 were protected from subsequent CYNMV infections in the field for 5 years, whereas non-inoculated plants were easily infected with CYNMV. Furthermore, KM3 infection did not induce the deterioration of the internal quality of the tubers. Total tuber and grade A tuber yields of KM3-infected plants were 25 and 57 % higher, respectively, than those of the non-inoculated plants after 5 years of cultivation. Additionally, grade A tuber yield of KM3-infected plants was 31 % higher than that of the non-inoculated plants grown from virus-free seed tuber. The results of this study indicate that KM3 is an effective agent for controlling necrotic mosaic disease in cv. Nagaimo.

마(Dioscorea japonica) 분말 첨가 프랑크푸르터 소시지의 품질과 저장 특성

Quality changes in frankfurter sausages with yam (Dioscorea japonica) powder added were investigated during their storage at 10°C for six weeks. The sausage samples were prepared using four concentrations of yam powder: 0% (C), 0.5% (T1), 1.0% (T2), and 2.0% (w/w) (T3). After the addition of yam powder, the crude protein contents decreased, but the crude fat and carbohydrate contents increased. The thiobarbituric acid values during the storage of the frankfurter sausages were lower in the samples with higher yam concentrations. Over the storage period, the volatile basic nitrogen values increased with the increase in the amount of added yam. With the increase in the yam concentration, the L* and a* values tended to decrease, whereas the b* value increased. The instrumental texture analysis showed that the hardness value decreased with the increase in the yam concentration. The first indication of sensorial quality deterioration was noticed at week 4 for T3 and at week 5 for C, T1, and T2. In conclusion, the quality and shelf-life of the frankfurter sausages were not noticeably influenced by the addition of yam powder with a concentration of up to 1.0% (w/w), but the functional and health-promoting effects of yam were positively incorporated.