Dioscorea Rotundata Research Articles

Potential for Biological Control of Postharvest Fungal Rot of White Yam (Dioscorea rotundata Poir) Tubers in Storage with Trichoderma harzianum

Potential of Trichoderma harzianum for biological control of postharvest fungal rot of white yam (Dioscorea rotundata Poir) tubers in storage was studied. Pathogenicity test revealed the susceptibility of healthy looking yam tubers to Aspergillus niger, Botryodiplodia theobromae and Fusarium oxysporum f. sp. melonganae after fourteen days of inoculation. Treatments comprising A. niger, B. theobromae and F. oxysporum each paired with T. harzianum and were arranged in completely randomized design and stored for five months between December, 2015 and April, 2016 and December, 2016 and April, 2017. Results revealed that tubers treated with the pathogenic fungi alone caused mean percentage rot of between 6.67% (F. oxysporum) and 22.22% (A. niger) while the paired treatments produced only between 2.22% (T. harzianum X F. oxysporum) and 6.67% (T. harzianum X A. niger). In the second year of storage, mean percentage rots were between 13.33% (F. oxysporum) and 28.89% (A. niger) while in the paired treatment rots were only between 6.67% (F. oxysporum X T. harzianum) and 8.89% (A. niger X T. harzianum). Tubers treated with antagonist alone produced 0.00% and 2.22% in the first and second year respectively. Result revealed that there was a significant difference (P ≤ 0.05) in mean percentage rot between the first year and the second year except where B. theobromae was inoculated alone, A. niger and T. harzianum paired and B. theobromae and T. harzianum paired. The most antagonized fungus in paired treatment for both years was F. oxysporum f. sp. melonganae while the least antagonized was A. niger and B. theobromae. The study recommended the use of T. harzianum in the control of rot causing pathogens of yam tubers in storage as better alternative ways of reducing tuber rot compared with the use of chemical fungicides which are environmentally hazardous.

Glycemic index of different varieties of yam as influenced by boiling, frying and roasting.

Yam is one of the commonly consumed carbohydrate staples. The objective of this work was to investigate the effect of boiling, roasting, and frying on the glycemic index (GI) of white yam (Dioscorea rotundata), yellow yam (Dioscorea cayenesis), and water yam (Dioscorea alata). Yam tubers were obtained (peeled, sliced, washed) deep fried in vegetable oil for 35–40 min and boiled in water for about 35–45 min. Sliced unpeeled tubers were also roasted at about 120°C for 40–45 min. The cooked yam samples were fed to 10 healthy subjects aged between 20–50 years. A glucometer was used to measure the blood glucose concentrations of the test individuals before consuming the yam diets and after the 15th, 30th, 45th, 60th, 90th, and 120th min of consumption. The average incremental area under the curves (IAUC) obtained from the recorded blood glucose concentrations were used to calculate the GI of various yam diets. The GI of the yam diets were found to be in the following increasing order: White‐yam‐boiled (44.26%) < Water‐yam‐boiled (50.12%) < White‐yam‐roasted (50.62%) < Water‐yam‐roasted (54.04%) < White‐yam‐fried (59.13%) < Yellow‐yam‐fried (65.08%) < Water‐yam‐fried (69.16%) < Yellow‐yam‐roasted (70.62%) < Yellow‐yam‐boiled (75.18%). White yam diets relatively had lower GI compared to yellow yam and water yam. Boiling was found to give generally lower GI in the white and water yams and could therefore be applied in the preparation of lower GI diets for diabetics.

Genetic parameters, prediction, and selection in a white Guinea yam early-generation breeding population using pedigree information.

Better understanding of the genetic control of traits in breeding populations is crucial for the selection of superior varieties and parents. This study aimed to assess genetic parameters and breeding values for six essential traits in a white Guinea yam (Dioscorea rotundata Poir.) breeding population. For this, pedigree‐based best linear unbiased prediction (P‐BLUP) was used. The results revealed significant nonadditive genetic variances and medium to high (.45–.79) broad‐sense heritability estimates for the traits studied. The pattern of associations among the genetic values of the traits suggests that selection based on a multiple‐trait selection index has potential for identifying superior breeding lines. Parental breeding values predicted using progeny performance identified 13 clones with high genetic potential for simultaneous improvement of the measured traits in the yam breeding program. Subsets of progeny were identified for intermating or further variety testing based on additive genetic and total genetic values. Selection of the top 5% progenies based on the multi‐trait index revealed positive genetic gains for fresh tuber yield (t ha−1), tuber yield (kg plant−1), and average tuber weight (kg). However, genetic gain was negative for tuber dry matter content and Yam mosaic virus resistance in comparison with standard varieties. Our results show the relevance of P‐BLUP for the selection of superior parental clones and progenies with higher breeding values for interbreeding and higher genotypic value for variety development in yam.

Seed Viability, Seedling Growth and Yield in White Guinea Yam

The yam is an economic tuber crop utilized for food, feed, and various industrial applications. Botanical seed viability, seedling growth, and development are among factors that influence plant population dynamics, development, structure, and sustainability. However, little is known about seed viability, growth, and yield potential of seed-progenies developed using different mating designs. This study assessed seed germination, seedling growth, and yield traits in seed-progenies developed using North Carolina I (NC-1) and polycross mating designs. For this, seed germination and seedling nursery trials established using seed-progenies from different yam crosses were used. Results revealed that days to first seed germination (DAYFG), days to 50% germination (DAYSG), coefficient of velocity of germination, seed emergence speed (SES), germination index, final germination percent, and seedling vigor index significantly (p &lt; 0.05) varied within and among NC-1 and PC-derived families. The mean days to first seed germination (DFSG) and DAYSG seed-progenies of NC-1 were significantly lower than the polycross progenies. Moreover, the seedling-progenies from the polycross produced a higher number of stems and more elongate tubers than those originated from the NC-1 mating. Progenies of family TDr1687 from a polycross mating were among the families that had the highest stem number (2.2), longest tuber (7.5 cm), and widest tuber (2.8 cm). The inter-family means of both NC-1 and polycross had a non-significant variation for mean tuber weight per plant. Our results suggest the relevance of seed germination and seedling attributes for selection of superior progenies at the early generation stage trials in yam breeding.

Physical Characteristics and Nutritional Analysis of Native and Chemically Mod- ified Starches Obtained From Yam (Dioscorea Rotundata) and Cassava (Manihot Esculeta) Tubers

Physical Characteristics and Nutritional Analysis of Native and Chemically Mod- ified Starches Obtained From Yam (Dioscorea Rotundata) and Cassava (Manihot Esculeta) Tubers

Community perceptions on causes of high dizygotic twinning rate in Igbo-Ora, South-west Nigeria: A qualitative study.

Dizygotic (DZ, non-identical) twinning rates vary widely across different regions in the world. With a DZ twinning rate of 45 per 1000 live births, Igbo-Ora Community in South-west Nigeria has the highest dizygotic (DZ) twinning rate in the world. Although several postulations exist on the causes of high DZ twinning rates in Igbo-Ora, no study has yet been conclusive on a definite causative agent. Using qualitative methods, this study explored the perceptions and beliefs of Igbo-Ora residents about the causes of high DZ twinning rates. Focus group discussion sessions and key informant interviews were organized among fathers and mothers of twins, those without twins, and health care providers. Key informant interviews were also held with persons considered to be custodians of culture who may have knowledge relevant to twinning such as traditional rulers, and traditional birth attendants; as well as health care providers, mothers and fathers of twins, and adult twins. The results showed three factors featuring as the leading perceived causes of twinning in the community. These included twinning being an act of God, hereditary, and being due to certain foods consumed in the community. Contrary to reports that the consumption of a species of yam (Dioscorea rotundata) may be responsible for the DZ twinning in this Community; yam was not prioritized by the respondents as associated with twinning. In contrast, participants repeatedly mentioned the consumption of "ilasa" a soup prepared with okra leaves (Abelmoschus esculenta) with water that is obtained from the community, and "amala" a local delicacy produced from cassava (Manihot esculenta) as the most likely dietary factors responsible for twinning in the community. Since the same foods are consumed in neighboring communities that have lower rates of twinning, we conjecture that nutritional and other environmental factors may produce epigenetic modifications that influence high DZ twinning rates in Igbo-Ora community. We conclude that more directed scientific studies based on these findings are required to further elucidate the etiology of the high rate of DZ twinning in Igbo-Ora.

Genome analyses reveal the hybrid origin of the staple crop white Guinea yam (Dioscorea rotundata)

White Guinea yam (Dioscorea rotundata) is an important staple tuber crop in West Africa. However, its origin remains unclear. In this study, we resequenced 336 accessions of white Guinea yam and compared them with the sequences of wild Dioscorea species using an improved reference genome sequence of D. rotundata In contrast to a previous study suggesting that D. rotundata originated from a subgroup of Dioscorea praehensilis, our results suggest a hybrid origin of white Guinea yam from crosses between the wild rainforest species D. praehensilis and the savannah-adapted species Dioscorea abyssinica We identified a greater genomic contribution from D. abyssinica in the sex chromosome of Guinea yam and extensive introgression around the SWEETIE gene. Our findings point to a complex domestication scenario for Guinea yam and highlight the importance of wild species as gene donors for improving this crop through molecular breeding.

EFFECT OF STORAGE AND INSECT INFESTATION ON PHYSICO CHEMICAL AND NUTRITIVE VALUES OF SUN DRIED YAM (DIOSCOREA ROTUNDATA)

Effect of storage and insect infestation on physicochemical and nutritive values of sundried yam (Dioscorea Rotundata) were studied. The samples were subjected to proximate and elemental analyses. There was a decrease in carbohydrate value of the infested yam compared with the uninfested yam which was also found to be lower than that of the raw yam. Copper, zinc, iron, magnesium, potassium, calcium and sodium were found to be 72.69 mg/100g, 70.58 mg/100g, 78.88 mg/100g, 71.70 mg/100g, 76.60 mg/100g, 60.06 mg/100g and 50.35 mg/100g in uninfested yam while the values of the mineral elements in the infested yam samples were obtained as 76.22 mg/100g, 75.91 mg/100g, 77.02 mg/100g, 76.08 mg/100g, 80.04 mg/100g, 64.55 mg/100g, 52.02 mg/100g compared to the raw yam which gave 74.44 mg/100g, 73.58 mg/100g, 79.99 mg/100g, 75.48 mg/100g, 78.26 mg/100g, 72.98 mg/100g and 51.50 mg/100g respectively. The Results showed that the samples were non–resistant to insect infestation with acute deterioration in food values.

Thermal and Morphological Characterization of Native and Plasticized Starches of Sweet Potato (Ipomoea batatas) and Diamante Yam (Dioscorea rotundata)

The objective of this study is to determine the morphological, physicochemical, and thermal properties of starches from two species of tubers, Ipomoea batatas (SP) and Dioscorea rotundata (DY), as well as the influence of glycerol as a plasticizer. The amylose/amylopectin content is 25.59/74.4 in DY; the granules are round and elliptical in shape with an average size of 25.5 $${\upmu }\text{m}$$ , and the degradation temperature is 311.01 °C. The amylose/amylopectin content is 45.9/54.1 in SP; the granules are polygonal, oval, and semi-oval in shape with an average size of 9.5 $${\upmu }\text{m}$$ , and the degradation temperature of 312.89 °C. The morphology of the granules in the different starch/glycerol formulations showed no structural damage to both species. However, increased degradation temperature was observed in the plasticized starches and in the shape and intensity of the band. Results indicate that the addition of glycerol improves the properties of native starches for processing and their potential use as bioplastics.

Plant Sex Prediction Using Genetic Markers in Cultivated Yams (Dioscorea rotundata Poir.) in Benin

Dioscorea rotundata Poir. is mainly dioecious but it also produces monoecious individuals. Recently two genetic markers were proposed to determine the sex in this species. We tested them in 119 individuals from 101 different cultivars of the national collection of Benin to verify whether they can predict the sex observed in the field. Among the analyzed individuals, 72 were male, 37 were female, 7 were monoecious and 3 were non-flowering. Our results showed that the marker sp16, associated with the W allele (female allele), was present in all female individuals but also in more than 42% of male individuals. Thus, while the absence of sp16 confirmed the male sex of the individuals, its presence did not allow sex discrimination. The marker sp1 allowed the identification of four genotypes (AA, AB, BB and AC) in the analyzed individuals with AA and AB being the most represented. Although AA was observed in 62.16% of female individuals and AB in 83.33% of male individuals, we did not observe a clear correlation between sp1 genotypes and sex identity. We concluded that the tested markers did not allow a clear sex discrimination in Beninese Dioscorea rotundata cultivars. Our results also suggest that Beninese D. rotundata cultivars have adopted a male XX/XY heterogametic system that is undergoing reorganization.

Environmental and economic impacts of pesticide treatment in the Yam Minisett Technique

AbstractWhite yam (Dioscorea rotundata) is an important tuber crop in a number of countries, but especially in West Africa where it serves as a food staple as well as a cash crop as excess production is sold in local markets. But the availability of quality planting material, most notably seed yams, for yam production remains an important constraint for farmers. Techniques have been developed to help address this limitation by cutting yam tubers into pieces (minisetts), treating them with the pesticide either via a seed dressing dust or pesticide ‘dips’ and planting to grow seed yams of the required size and quality. But while there have been many studies on the agronomy and adoption by farmers of these techniques, there have been fewer studies on their economic performance. Indeed, to date there have been no studies that compare the economic performance of treating setts compared to leaving them untreated, and neither has there been any analysis of the environmental impact of treating setts. This paper reports the results of a study designed to address these two gaps in knowledge and is based upon results from a series of farmer-managed seed yam plots established in the middle belt of Nigeria over 4 years (2013–2016). Results suggest that revenue and gross margin were higher for treated versus untreated setts although the latter still performed relatively well. Using the Field Use Environmental Impact Quotient (EIQ), the commonly recommended pesticide sett treatments were estimated to have a low-to-moderate environmental impact, and further research is needed to see how far pesticide use can be reduced to still be effective and minimise any environmental impact.

Growth parameters, mineral distribution, chlorophyll content, biochemical constituents and non-enzymatic antioxidant compounds of white yam (Dioscorea rotundata (L) var. gana) grown under salinity stress

Soil salinity has a negative impact on crop production over the world. The effect of salt stress on growth, chlorophyll content, mineral distribution, biochemical constituents and non-enzymatic antioxidant compounds of white yam (Dioscorea rotundata (L) var. gana) cultivar regularly consumed in Cameroon were investigated. Plants were subjected to four different levels concentrations of NaCl (0, 50, 100 and 200 mM), with 0 mM NaCl as a control. The supply of intake doses of NaCl in the culture medium significantly (P < 0.001) decreased the dry biomass (roots and shoots), growth parameters (number of leaves, noose diameter, leaf area and stem height) and chlorophyll contents from 100 mM NaCl. Mineral elements (K, Ca and Mg) and K/Na ratio significantly (P < 0.001) decreased in roots and shoots with increasing salinity. The higher sodium (Na) concentrations were recorded in shoots than in roots. The different biochemical constituents (proline (PRO), total soluble carbohydrates (CH), soluble proteins (PR) and total free amino acids (FAA)) and non-enzymatic antioxidants compounds (total phenolic (TP) and flavonoids (FLA) contents) significantly (P < 0.001) increased from 50 mM NaCl. The main strategy in cv. gana seems to increase osmotic adjustment through high accumulation of CH, PR, FAA and PRO in the leaves and they could eventually be considered as biochemical indicators of early selection and osmotic adjustment ability for salt tolerant plants. The gana variety could be encouraged to be planted on salt affected soils for the better development in salty areas.

Functional properties of three native starches and their modified derivatives

Starches were isolated from cocoyam (Xanthosoma sagittifollium), white yam (Dioscorea rotundata) and bitter yam (Dioscorea dumentorum). Starch modification was carried out using acetic anhydride and phthalic anhydride. The native and modified starches were characterized using Fourier Transformed Infra-red Spectroscopy (FTIR) for identification of the functional groups. Functional properties such as water absorption capacities, oil absorption capacity, swelling power, solubility, gelation temperature, least gelation capacity, amylose content and pH were determined using standard procedures. Acetylation increased the water absorption capacity, oil absorption capacity, swelling power, amylose content, and solubility of the starches while phthalation decreased water absorption capacity, oil absorption capacity, swelling power, and solubility of the starches. Native cocoyam starch has the highest gelation temperature (85 °C) while Acetylated bitter yam has the lowest gelation temperature (74 °C). The pH of the native and modified starches was within the range of 4.14 − 6.55. Phthalation and acetylation increased the bulk density of the starches. Native cocoyam, white yam, and bitter yam starches had the lowest gelation concentration (6%). Modification of native starches will improve the usage of starch in food and non-food applications.

Multinomial Regression Analysis if Yam (Dioscorea Spp.) Consumers’ Preferences and Varietal Diversification Pattern in Nigeria

Multinomial regression analysis of yam consumers’ preference and varietal diversification in the yam production system in Nigeria was the thrust of this investigation. Five major yam farming communities were sampled randomly to get 200 respondents (suppliers and consumers) of yam. Parametric and non-parametric tests were employed to analyze the primary data collected with the questionnaire. The result indicates that white yam (Dioscorea rotundata) is the dominant variety among consuming households. The majority of the respondents prefer selling of white yam (76%) followed by water yam (13%) and yellow yam (l1%) in response to consumers’ preferences. The mean value of yam supplied was 505.34kg, while the mean quantity consumed was 14.56kg. The finding shows that the statistical relationship between the varieties consumed and supplied is strong and positive. It was concluded that as the demand-end is willing to purchase more quantity of white yam supplied, yam farmers and marketers are advised to scale-up production and supply respectively to take advantage of the increasing market demand for white yam in Nigeria. Also, more research works on yam varieties should be conducted by researchers to expand the value chain / industrial uses of other yam varieties to prevent their extinction.

Comparative assessment of genetic diversity matrices and clustering methods in white Guinea yam (Dioscorea rotundata) based on morphological and molecular markers

Understanding the diversity and genetic relationships among and within crop germplasm is invaluable for genetic improvement. This study assessed genetic diversity in a panel of 173 D. rotundata accessions using joint analysis for 23 morphological traits and 136,429 SNP markers from the whole-genome resequencing platform. Various diversity matrices and clustering methods were evaluated for a comprehensive characterization of genetic diversity in white Guinea yam from West Africa at phenotypic and molecular levels. The translation of the different diversity matrices from the phenotypic and genomic information into distinct groups varied with the hierarchal clustering methods used. Gower distance matrix based on phenotypic data and identity by state (IBS) distance matrix based on SNP data with the UPGMA clustering method found the best fit to dissect the genetic relationship in current set materials. However, the grouping pattern was inconsistent (r = − 0.05) between the morphological and molecular distance matrices due to the non-overlapping information between the two data types. Joint analysis for the phenotypic and molecular information maximized a comprehensive estimate of the actual diversity in the evaluated materials. The results from our study provide valuable insights for measuring quantitative genetic variability for breeding and genetic studies in yam and other root and tuber crops.

A meta-analysis of the technical efficiency of yam production in Nigeria

ABSTRACT The paper presents the first meta-analysis of yam (Dioscorea rotundata Poir) production studies in Nigeria, with a special emphasis on technical efficiency. The focus was on published studies in journal papers and conferences. For the meta-analysis of production function, a total of 40 studies were included for ware yam and 3 for seed yam, for technical efficiency a total of 23 ware yam and 3 seed yam studies were included and for the farm budget meta-analysis, a total of 22 ware yam and 6 seed yam studies were included. The “peak” years of publication of the ware yam studies were from 2012 to 2014. The bulk of the studies took place in the major yam-growing states, such as Ekiti, Benue, and Kogi. Technical efficiency of yam production varied between and within each of the studies, with an average technical efficiency across studies of between 0.6 and 0.8. The studies highlight the importance of knowledge; it is not just about the quantity of inputs applied but how they are used that matters. The paper notes that meta-analyses of studies designed to explore the factors influencing production of agricultural crops in Nigeria are relatively sparse in number, yet given the importance of agriculture in the country, both for the livelihoods of millions of people, and export, then more such analyses are needed.

Comparative evaluation of instant 'poundo' cocoyam (Colocasia esculenta) and yam (Dioscorea rotundata) flours produced by flash and cabinet drying

SummaryCocoyam, an important staple crop especially among the low‐income earners in tropical regions of the world, is highly underutilised for industrial applications. This study investigates the nutritional, colour and rheological properties of instant flours (‘poundo’) from two cultivars of Colocasia esculenta (white‐NCe010 and purple‐NCe003) and Dioscorea rotundata (var. Oginni), and sensory attributes of doughs prepared from reconstituted flours. Tubers were processed into instant flours using cabinet and flash drying methods. Significant differences (P &lt; 0.05) in the proximate and mineral composition and pasting properties of flours were found. Sensory panellists rated reconstituted poundo yam (8.17–8.20) and white cocoyam (7.50–7.95) higher than purple cocoyam (6.60–7.10) meals. Influence of drying method on sensory characteristics of flours was not significant. Instant poundo cocoyam and yam flours could serve as novel convenience and ready‐to‐eat food products which could contribute to increasing the commercial and industrial application options for these underutilised tubers beyond their present basic use.

Phoenix dactylifera Linn fruit based-diets palliate hyperglycemia in alloxan-induced diabetic rats.

Objectives This study was designed to examine the in vitro inhibitory activities of vital enzymes related to diabetes mellitus and different biochemical parameters of Phoenix dactylifera fruit based-diet in alloxan-induced diabetic rats. Methods The aqueous extract of P.dactylifera fruit based-diet was prepared and used for determination of in vitro antioxidants as well as α-amylase and α-glucosidase inhibitory activities using standard procedures. Also, 30 albino rats were induced by a single intraperitoneal injection of 150mg/kg body weight of alloxan and grouped into A-D as normal rats placed on Dioscorea rotundata based-diet, diabetic control rats placed on D.rotundata based-diet, diabetic rats placed on D.rotundata based-diet and administered metformin orally per day, and diabetic rats placed on P.dactylifera fruit based-diet respectively. The animals were sacrificed on the fourth week of the experiment, and different biochemical parameters were evaluated. Results The P.dactylifera fruit based-diet extract demonstrated antioxidative potentials and inhibition against α-amylase and α-glucosidase activities in a dose-dependent manner. In addition, diabetic rats placed on the P.dactylifera fruit based-diet revealed significant (p<0.05) increase in body weight, insulin and glycogen levels, antioxidant enzyme activities, GLUT 2 and high density lipoprotein (HDL) concentrations when compared with the diabetic control group. Also, diabetic rats placed on P.dactylifera fruit based-diet indicate significant (p<0.05) reduction in fasting blood glucose, lipid peroxidation, cytokines levels, some gluconeogenesis enzyme activities, cholesterol, triglycerides, low-density lipoproteins and very low-density lipoproteins concentrations compared to the diabetic control animals. Conclusion This diet could be an alternative nutraceutical means of managing diabetes mellitus and its complications.

Sample Preservation and Plant Sex Prediction in White Guinea yam (Dioscorea rotundata Poir.)

Introduction: Yam (Dioscorea spp.) is an economically important staple food in tropical regions, especially for people in West Africa. Understanding of the flowering behavior of the crop to determine potential manipulation available to accomplish crop improvement at early stage remain key challenge in the yam breeding. The methods that reliably yield quality DNA and distinguishing sex type at the early stage of growth have been a challenge in yam genetics and breeding studies. This study assessed the effect of sample preservation methods on DNA quantity and quality during extraction and potential of DNA marker to diagnose plant sex at the early seedling stage in white Guinea yam. Materials and Methods: Five sample preservation methods were assessed for quality DNA extraction during field leaf tissue collection, namely liquid nitrogen, dry ice, silica gel, 95% ethanol, and oven drying. The predicted sex at the seedling stage using the molecular marker was further validated with the visual score for the sex phenotype at the flowering stage. Results: According to the findings of the present study, the DNA extracted from leaf samples preserved in liquid nitrogen, silica gel, dry ice, and oven drying methods were higher in molecular weights than samples stored in ethanol solution. Yam plant sex diagnosis with the DNA marker (sp16) identified a higher proportion of ZW genotypes (female or monoecious phenotypes) than the ZZ genotypes (male phenotypes) in the studied materials with 74% prediction accuracy. Conclusions: The results from this study provided valuable insights on suitable sample preservation methods for quality DNA extraction and the potential of DNA marker sp16 to predict sex in white Guinea yam.

Seed yam production from whole tubers versus minisetts

ABSTRACT Yam (Dioscorea rotundata Poir.) is a major staple and cash crop for millions of households in West Africa, where about 93% of the world crop is produced. The tuber serves as food and seed. Depending on the size, seed tubers are often cut into setts, minisetts, or planted whole. An experiment was conducted to investigate the effects of using whole tubers versus minisetts to produce seed yams. Six treatments constituted combinations of whole tubers and minisetts, and three tuber-size classes, viz., 30–59 g, 60–89 g, and 90–120 g (averaged and referred to as 45 g, 75 g, and 105 g, respectively). The experiment was conducted as a randomized complete block design with three replications. Results showed that plants from whole tubers emerged from the soil faster and yielded 48% more than those from minisetts. The mean yield of 105 g minisetts (18.3 t/ha) was statistically similar to that of 45 g whole seed (17.9 t/ha). Using 45 g whole seed would save about 2 t/ha of the harvested crop for use as food instead of seed. So, planting small whole tubers is more profitable than minisetts and is recommended to yam growers.