Dioscorea Rotundata Poir Research Articles

Genome-wide mapping uncovers significant quantitative trait loci associated with yam mosaic virus infection, yield and dry matter content in White Guinea yam (Dioscorea rotundata Poir.)

Genome-wide mapping uncovers significant quantitative trait loci associated with yam mosaic virus infection, yield and dry matter content in White Guinea yam (Dioscorea rotundata Poir.)

Effects of silver nitrate on in vitro development of yam (Dioscorea rotundata Poir) plants

Effects of silver nitrate on in vitro development of yam (Dioscorea rotundata Poir) plants

Ethno-Botanical Studies of Post-harvest Rot of White Yam (Dioscorea rotundata Poir.) in the Five South-eastern States of Nigeria

White yam (Dioscorea rotundata Poir.) is the most important species of yam in West Africa cultivated for the consumption of its starchy tuber. Indigenous knowledge and usage of white yam in some parts of South-Eastern, Nigeria was investigated. This research work aimed at conducting ethno-botanical studies of post harvest rot of white yam in the five South-Eastern states of Nigeria. A well-structured, pre-tested questionnaire on cultivation, post harvest handling of yam, and conservation was designed and administered to obtain crucial information from the respondents within the study area. Five South-Eastern states of Nigeria namely; Abia, Anambra, Ebonyi, Enugu and Imo states were randomly surveyed. Ethno-botanical studies revealed that five hundred and eighty two households about 97% of the respondents were interviewed out of the six hundred questionnaires administered which were successfully retrieved and fully responded to. It was observed that more men (63.67%) were involved in yam farming than women (33.33%) who engage in yam farming. Overall, respondents within the study area who were aware of the indigenous knowledge of yam were significantly (P˂0.05) higher than those who were unaware. This ethno-botanical study revealed the traditional concepts and practices relating to yam cultivation and its conservation. Findings from this survey will be utilized as a basis for further investigations on emerging indigenous practices and sustainability impact.

Trends in genetic gain for yam in the IITA breeding program

AbstractMonitoring genetic gain is crucial to ensure breeding programs' effectiveness and identify potential challenges and areas for their improvement. Our study provides a first overview of the trends in genetic gain for tuber yield and disease resistance traits in the IITA's (International Institute of Tropical Agriculture) yam breeding program. We used historical data (2010–2022) from multiple generations of past breeding cycles evaluated at 31 sites in the white Guinea yam (Dioscorea rotundata Poir) breeding pipeline and 28 sites in the water yam (Dioscorea alata L.) breeding pipeline of IITA and its national partners in West Africa. Our result shows positive genetic trends in fresh tuber yield while recording a gain of 1.38% or 99.17 kg ha−1 per year in the white Guinea yam and 2.18% or 252.41 kg ha−1 per year in the water yam breeding pipelines. Genetic trends for virus and anthracnose resistance were in the desired direction but negligible in white Guinea yam, while significant for virus and nonsignificant for anthracnose resistance in water yam. Our findings indicate that while the breeding program has succeeded in enhancing tuber yield, post‐harvest tuber dry matter content and disease resistance (yam mosaic virus and anthracnose) did not follow a similar trend in the material being developed. This implies that the yam breeding program needs to strike a balance between various traits, ensuring that increased yield does not come at a cost to food quality or disease resistance. Our results highlight the importance of continually monitoring and assessing the performance of a breeding program and making informed decisions about which traits to focus on for future improvement.

Changes in the rhizosphere and root-associated bacteria community of white Guinea yam (Dioscorea rotundata Poir.) impacted by genotype and nitrogen fertilization

The bacterial diversity and composition of water yam (Dioscorea alata L. cv. A-19), which can grow without chemical fertilization, have recently been characterized with no significant differences compared with the use of chemical fertilization. However, the diversity and community structure of bacteria associated with the white Guinea yam (Dioscorea rotundata), the most cultivated and economically important yam in West Africa, have not yet been investigated. This study characterized the bacterial diversity and composition associated with bulk soil, rhizosphere, and plant roots in six white Guinea yam genotypes (S004, S020, S032, S042, S058, and S074) in field experiments in Ibadan, Nigeria under N-based chemical fertilizer application. The largest diversity of bacteria was found in the bulk soil, followed by the rhizosphere and roots. Based on the alpha diversity analysis, the bacterial diversity in both S020 and S042 increased with fertilizer application among the bulk soil samples. S058 grown under no-fertilizer conditions had the highest bacterial diversity among the rhizosphere samples. Beta diversity analysis highlighted the significant difference in the composition of bacteria associated with the genotypes and fertilizer treatments, and S032 had a unique bacterial composition compared to the other genotypes. The dominant phylum across all sample types was Proteobacteria. Actinobacteriota was the dominant phylum among bulk soil samples. At the genus level, Bacillus was the most abundant bacterial genus across both the control and treated samples. Pseudomonas was predominant across all rhizosphere samples. Chryseobacterium, Sphingobium, Delftia and Klebsiella associated with the rhizosphere were shown the altered relative abundance between the control and treated samples depending on genotypes. A genus related to symbiotic nitrogen-fixing bacteria, the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade, showed higher relative abundance among all root samples, indicating that it is a core bacterial genus. Furthermore, the field application of chemical fertilizer had a significant impact on the relative abundances of two genera related to symbiotic nitrogen-fixers, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade and Bradyrhizobium in the rhizosphere and root. These results suggest that N-based chemical fertilizers and plant genotypes would influence the compositional arrangement of associated bacterial communities, including symbiotic nitrogen-fixing bacteria.

Effect of tillage, fertilizers and storage structures on quality shelf life of white yam (Dioscorea rotundata Poir) in south west Nigeria

This study examined the effect of tillage, fertilizers and storage structures on quality shelf life of white yam in South West Nigeria. The study was a factorial experiment consisting of Tillage, Fertilizers and Storage Structure. The tillage system involved Heap Tillage (HT) and Ridge Tillage (RT), while Fertilizers involved Poultry Manure (PM), N15P15K15 (NPK) and Control (CLT) and two types of Storage Structures namely; Traditional Barn (TB) and Open Sided Storage Structure (OSSS) were combined to form the treatments. The experiment was a 2x3x2 factorial combination arranged in a Randomised Complete Block Design (RCBD). The treatments were replicated three times for each location respectively. A total of 72 ridges and 144 heaps were used to make a population of 288 plants per location. The tubers were weighed to ensure uniformity before planting. The plot size was 18mx18m square with a pathway of 1.0m between blocks making a total of 324 square metres. At harvest, the tubers were weighed immediately. They were then kept separately in the two storage structures namely: Traditional Barn (TB) and the Open Side Storage Structure (OSSS) for a period of 3 months. After the 3rd months of storage, the tubers were examined and data collected. The weight of each tuber from each storage structure was taken periodically to evaluate the weight loss and assess the keeping quality periodically. The findings of this study demonstrated the significant influence of tillage, fertilizers, and storage structures on the quality, shelf life, nutrient use efficiency, and nutrient composition of white yam. Excessive fertilizer application was found to increase rotting and deterioration levels. Hence, farmers and stakeholders should carefully consider fertilizer application rates to minimize post-harvest losses and enhance food security. Further investigations are needed to explore the underlying mechanisms responsible for the observed effects and to optimize fertilizer management practices for yam storage. Organic fertilization enhances the nutrient use efficiency and nutritional quality of yam, while appropriate storage structures, play a crucial role in preserving the quality and extending the shelf life of the harvested tubers. Based on the result of the study, open sided storage should be considered by producers of yams for storing their harvested tubers due to the facts that, it performed well in minimizing nutrient lost, weight loss and decay to considerable level and prevented pests/rodents attack on yam tubers.

Identification of diagnostic KASP‐SNP markers for routine breeding activities in yam (Dioscorea spp.)

AbstractMaintaining genetic purity and true‐to‐type clone identification are important action steps in breeding programs. This study aimed to develop a universal set of kompetitive allele‐specific polymerase chain reaction (KASP)‐based single nucleotide polymorphism (SNP) markers for routine breeding activities. Ultra‐low‐density SNP markers were created using an initial set of 173,675 SNPs that were obtained from whole‐genome resequencing of 333 diverse white Guinea yam (Dioscorea rotundata Poir) genotypes. From whole‐genome resequencing data, 99 putative SNP markers were found and successfully converted to high‐throughput KASP genotyping assays. The markers set was validated on 374 genotypes representing six yam species. Out of the 99 markers, 50 were highly polymorphic across the species and could distinguish different yam species and pedigree origins. The selected SNP markers classified the validation population based on the different yam species and identified potential duplicates within yam species. Through penalized analysis, the male parent of progenies involved in polycrosses was successfully predicted and validated. Our research was a trailblazer in validating KASP‐based SNP assays for species identification, parental fingerprinting, and quality control (QC) and quality assurance (QA) in yam breeding programs.

Comparative Metabolomics Profiling Reveals Key Metabolites and Associated Pathways Regulating Tuber Dormancy in White Yam (Dioscorea rotundata Poir.).

Yams are economic and medicinal crops with a long growth cycle, spanning between 9-11 months due to their prolonged tuber dormancy. Tuber dormancy has constituted a major constraint in yam production and genetic improvement. In this study, we performed non-targeted comparative metabolomic profiling of tubers of two white yam genotypes, (Obiaoturugo and TDr1100873), to identify metabolites and associated pathways that regulate yam tuber dormancy using gas chromatography-mass spectrometry (GC-MS). Yam tubers were sampled between 42 days after physiological maturity (DAPM) till tuber sprouting. The sampling points include 42-DAPM, 56-DAPM, 87DAPM, 101-DAPM, 115-DAPM, and 143-DAPM. A total of 949 metabolites were annotated, 559 in TDr1100873 and 390 in Obiaoturugo. A total of 39 differentially accumulated metabolites (DAMs) were identified across the studied tuber dormancy stages in the two genotypes. A total of 27 DAMs were conserved between the two genotypes, whereas 5 DAMs were unique in the tubers of TDr1100873 and 7 DAMs were in the tubers of Obiaoturugo. The differentially accumulated metabolites (DAMs) spread across 14 major functional chemical groups. Amines and biogenic polyamines, amino acids and derivatives, alcohols, flavonoids, alkaloids, phenols, esters, coumarins, and phytohormone positively regulated yam tuber dormancy induction and maintenance, whereas fatty acids, lipids, nucleotides, carboxylic acids, sugars, terpenoids, benzoquinones, and benzene derivatives positively regulated dormancy breaking and sprouting in tubers of both yam genotypes. Metabolite set enrichment analysis (MSEA) revealed that 12 metabolisms were significantly enriched during yam tuber dormancy stages. Metabolic pathway topology analysis further revealed that six metabolic pathways (linoleic acid metabolic pathway, phenylalanine metabolic pathway, galactose metabolic pathway, starch and sucrose metabolic pathway, alanine-aspartate-glutamine metabolic pathways, and purine metabolic pathway) exerted significant impact on yam tuber dormancy regulation. This result provides vital insights into molecular mechanisms regulating yam tuber dormancy.

Effects of Poultry Manure on Soil Fertility, Growth and Yield of White Yam and Yellow Yam

Field experiments were conducted at Owo in the forest-savanna transition zone of southwestern Nigeria during 2007 and 2008cropping seasons to study the effect of different levels of poultry manure(0, 10, 20, 30 and 40 t/ha) on soil fertility, leaf nutrient content, growthand tuber yield of two species of yam; namely, white yam (Dioscorearotundata Poir) and yellow yam (Dioscorea cayenensis Lam). Thetreatments were factorially arranged in a randomized block design withthree replications. The soil was deficient in organic matter (OM), total N,available P, exchangeable K, Ca and Mg. The results showed that poultrymanure increased soil and leaf N, P, K, Ca and Mg, and soil OM, growthand tuber yield of the yams compared with the control treatments. Whiteyam produced significantly higher yield than yellow yam. Compared withyellow yam, white yam increased tuber yield by 19%, 26%, 36%, 3% and12%, respectively, for 0, 10, 20, 30 and 40 t/ha poultry manure.Application of poultry manure at 20 t/ha and 30 t/ha significantlyimproved growth and tuber yield of white yam and yellow yam,respectively, compared with the other treatments. These levels of poultrymanure are, therefore, recommended for the two yam species in forest-savanna transition zone of southwest Nigeria. Recommendations ofmanure for yam production should be variety specific.

Activated charcoal in the control of oxidation and in vitro growth of Dioscorea spp. nodal segments

In vitro oxidation is a problem for some herbaceous and woody species and can cause darkening of tissues and consequently death of explants and plants Therefore, this study aimed to assess the effect of activated charcoal on in vitro yam cultivation, aiming at reducing or eliminating explant oxidation and optimizing the growth of the genotypes Dioscorea alata var. purpurea (Roxb.) A. Pouchet and Dioscorea rotundata Poir. Nodal segments of approximately 1 cm, extracted from plants previously grown in vitro, were introduced into test tubes containing 10 mL of 2GGC culture medium, plus 30 g L-1 sucrose, solidified with 2.2 g L-1 Phytagel® and pH adjusted to 5.8 before autoclaving, containing activated charcoal doses of 0, 1, 2, 3 and 4 g L-1. Plants were maintained for 90 days in a growth room, with temperature of 27 ± 1ºC, photon flux density of 30 μmol m-2 s-1 and photoperiod of 16 hours, after which their development variables were evaluated. Activated charcoal, at the concentration of 4 g L-1 considerably promoted the best development of plants, and the species D. alata var. purpurea showed higher means for all variables studied.

Diversity of white Guinea yam (Dioscorea rotundataPoir.) cultivars from Benin as revealed by agro-morphological traits and SNP markers

AbstractWhite Guinea yam (Dioscorea rotundataPoir.) is indigenous to West Africa, a region that harbours the crop's tremendous landrace diversity. The knowledge and understanding of local cultivars’ genetic diversity are essential for properly managing genetic resources, conservation, sustainable use and their improvement through breeding. This study aimed to dissect phenotypic and molecular diversity of white yam cultivars from Benin using agro-morphological and single nucleotide polymorphism (SNP) markers. Eighty-eight Beninese white Guinea yam cultivars collected through a countrywide ethnobotanical survey were phenotyped with 53 traits and genotyped with 9725 DArT-SNP. Multivariate analysis using phenotypic traits revealed 30 traits as most discriminative and explained up to 80.78% of cultivars’ phenotypic variation. Assessment of diversity indices such as Shannon–Wiener (H′), inverse Shannon (H.B.), Simpson's (λ) index and Pilou evenness (J) based molecular and phenotypic data depicted a moderate genetic diversity in Beninese white Guinea yam cultivars. Genetic differentiation of cultivars among country production zones was low due to the high exchange of planting materials among farmers of different regions. However, there was high genetic diversity within regions. Hierarchical clusters (HCs) on phenotypic data revealed the presence of two groups while HCs based on the SNP markers and the combined analysis identified three genetic groups. Our result provided valuable insights into the Beninese white Guinea yam diversity for its proper conservation and improvement through breeding.

Variation in Tuber Dry Matter Content and Starch Pasting Properties of White Guinea Yam (Dioscorea rotundata) Genotypes Grown in Three Agroecologies of NIGERIA

The primary objective of this study was to assess the effects of genotype (G), location (L), and G × L interaction on tuber quality traits (dry matter content and starch pasting parameters) in white Guinea yam (Dioscorea rotundata Poir.). Variability in tuber dry matter and starch pasting properties was examined using 18 advanced breeding lines and two dominant landrace cultivars of white Guinea yam grown in three different agroecological zones (forest‒savanna transition, southern Guinea savanna, and rainforest) in Nigeria. The starch pasting properties were evaluated using a Rapid Visco Analyser. Our results show that the G × L interaction effect was low compared to the genotype and growing location effects on the variability of key starch properties. In addition, the repeatability of trait performance across locations was high and relatively uniform for key traits, suggesting that any of the three locations used in this study can be employed for their evaluation. Furthermore, TDr1100873 had a higher dry matter content than the dominant landrace cultivars (Amula and Meccakusa) but was similar to them in starch pasting properties. Hence, TDr1100873 is considered a suitable variety for future breeding activities.

Capacidad de infección de hongos asociados a la pudrición seca de los Tubérculos de Ñame

Dry rot of tubers is one of the most devastating diseases in yam production (Dioscorea rotundata Poir.) in the Caribbean region of Colombia. The disease attacks tubers causing production losses during the crop. In previous experiments, 11 fungal morphotypes were isolated and associated with this disease in yam crops in the Caribbean region of Colombia. The present investigation was carried out under greenhouse conditions to determine the infection capacity of these 11 possible causative agents, in 150-day-old plants of two yam genetic materials (0307-49SB y 0307-50CB). The results indicated that morphotypes DH2 (Lasiodiplodia theobromae), DH11 (Curvularia aeria), DH20 (Aspergillus niger), and DH17 (Fusarium equiseti), showed the highest infection capacity to yam tubers, regardless of the genetic material, therefore, they were considered as the main causal agents of the disease in the Caribbean region of Colombia. The remaining seven (7) morphotypes, despite having been inoculated in the roots of the plants, showed minor effects on tubers and affected other organs of the plant, especially stems and aerial part of yam plant. This study allows concentrating the research on these four morphotypes to develop crop management strategies that might allow reducing the incidence of this disease in the Caribbean region of Colombia.

Evaluation of seed of white yam (Dioscorea rotundata Poir) cultivars as influenced by minisett sizes in the Southern Guinea Savannah agro-ecological zone of Nigeria

Evaluation of seed of white yam (Dioscorea rotundata Poir) cultivars as influenced by minisett sizes in the Southern Guinea Savannah agro-ecological zone of Nigeria

Genetic parameter estimation and selection in advanced breeding population of white Guinea yam

ABSTRACT White Guinea yam (Dioscorea rotundata Poir.) is an important tuber crop grown extensively in tropical regions of West African yam belt. Tuber yield, dry matter content, and tolerance to yam mosaic virus are key traits used for identification and selection of superior varieties for commercial deployment. In this study, we estimated genetic parameters for fresh tuber yield, tuber dry matter content, and quantitative field tolerance to yam mosaic virus in 49 clones grown in multi-environment trials (METs). We conducted genomic prediction involving 6337 single nucleotide polymorphisms (SNPs) and phenotypic field evaluation of data collected on the three traits from four sites. Additive genetic and non-genetic factors contributed significantly to phenotypic variation of studied yam traits in METs but to varying degrees. The non-genetic effects were relatively high for most of the measured traits. Narrow-sense heritability values were low (<0.30) for all studied traits. Further analysis of the performance of the clones at test sites with additive main effects and multiplicative interaction (AMMI) analysis exhibited significant genotype by environment interactions (GEI) for the three traits. The AMMI identified TDr10/00412, TDr11/00055, and TDr09/00135 clones with lowest mean trait stability index and outstanding performance for fresh tuber yield (t ha−1), tuber dry matter, and mosaic virus resistance across sites. The elite clones identified could serve as useful source of alleles for the genetic improvement of the crop and possibly considered for release to farmers.

Genetic Diversity of White Yam (Dioscorea rotundata Poir) Accessions Maintained in Tissue Culture and Cultivated in Field using Simple Sequence Repeat (SSR) Markers and Morphological Characterization

Dioscorea rotundata is a staple food crop for millions of people in the tropical and subtropical regions. In vitro germplasm conservation is a very useful tool in yam improvement strategies but very little is known about the genetic integrity and stability of in-vitro conserved yam plants. In this study, 42 accessions from in vitro and field populations were genotyped using 11 microsatellite markers and 23 morphological descriptors to assess variability within and between accessions. Out of the 23 morphological variables used, 13 were identified as most discriminate and were used to cluster the accessions into 4 clusters using the unweighted pair group arithmetic mean average (UPGMA). Accession maintained in field as well as in in-vitro showed high genetic similarity (R2 = 0.91, p-value: 1e-04). Out of the 42 accessions analyzed, nine accessions maintained in the field and in-vitro displayed different genetic profiles. This study provided basic information on the possible somaclonal variation of yam accessions maintained through in-vitro. Further study with advanced tools such as next-generation sequencing is required to elucidate the nature of the observed variation within clones.

Simple sequence repeat‐based mini‐core collection for white Guinea yam (Dioscorea rotundata) germplasm

AbstractA core subset with a small number of accessions representing the genetic diversity of the base collection plays a vital role in facilitating efficient utilization of plant genetic resources. This is particularly relevant for vegetatively propagated large plant size tuber crops with a long growing period, such as white Guinea yam (Dioscorea rotundata Poir.). For the efficient utilization of D. rotundata genetic resources, this study was aimed at developing a mini‐core collection from a core collection of 447 D. rotundata accessions maintained at the International Institute of Tropical Agriculture (IITA). Accordingly, a D. rotundata mini‐core collection representing 102 accessions was selected using 16 simple sequence repeat (SSR) markers, retaining ∼98% of the SSR allelic diversity of the base collection. A similar level of diversity was captured within the mini‐core collection and the base collection with respect to 21 morphological traits, ploidy level, and geographic origin. The mini‐core collection demonstrated a wide range of variation in agronomic traits such as growth period, number of tubers, average tuber weight, and total yield per plant. This variation was considerable when compared with the variation observed for the same traits among the 10 lines or genotypes conventionally used in the breeding program at IITA, which were included in this study as checks. The selected mini‐core accessions could serve as a working collection to broaden the genetic variation for use in practical breeding programs, as well as in future genomic analyses aimed at the genetic improvement of D. rotundata in West Africa.

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.

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.

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.