Yam Bean Research Articles

Nutritional quality and physicochemical properties of biscuit from composite flour of wheat, African yam bean and tigernut

This study investigated the effect of the supplementation of wheat flour with flour blends of African yam bean (AYB) and tigernut for the production of biscuits and evaluated the sensory characteristics. The composite flours were of ratio 70:25:5 (TWB), 70:20:10 (ATW), 70:15:15 (BTT) for wheat: AYB: tigernut, respectively, while 100 % wheat flour served as control (WTY). The composite flour samples were analyzed for proximate, functional and pasting properties. The physical and chemical properties and sensory attributes of the developed biscuits were carried out. The moisture, protein, fat, ash, crude fiber, carbohydrate, and energy contents of the composite flour ranged from 6.63 to 8.13 %, 11.22–18.36 %, 13.27–19.15 %, 0.98–0.99 %, 3.96–7.43 %, 59.97–62.55 % and 400.89 to 410.40 Kcal/100g, respectively. The results showed that protein fat, ash and crude fiber of the biscuit were improved. The water and oil absorption capacity of composite flour was low while the pasting properties of the composite flour blends reduced as the AYB flour increased. All the composite flour blend biscuit samples possessed high essential nutrients and antioxidant potential. All the biscuits samples were accepted by the panelists, however, sample BTT (70 % wheat flour+15 % AYB flour+ 15 % tigernut flour) was most accepted in appearance, aroma, taste, crispness and overall acceptability. Therefore, biscuits from the flour blends of wheat, AYB and tigernut could be nutritionally beneficial and good for adults.

Estimation of Genetic Parameters for Selected Quantitative Traits in Introduced African Yam Bean (Sphenosylis stenocarpa Hochst. ex. A. Rich Harms) Genotypes

A solid understanding of the genetic control of traits within breeding populations is essential for selecting superior genotypes and parent plants for African yam bean (AYB) cultivation. In this study, we explored the phenotypic breeding values and genetic parameter estimates for various traits in 10 introduced AYB varieties. These traits included seed emergence speed (SES), seedling vigor index (SVI), final germination percentage (FGP), seed yield, days to first flower bud initiation (DAYSFBI), days to first flowering (DAYSF), and days to first pod initiation (DAYSPI). We conducted the trial using a randomized complete block (RCB) design with the following varieties: TSs2, TSs60, TSs11, TSs33, TSs282, TSs450, TSs10, TSs432, TSs424, and TSs151B. Traits showing high and medium genotypic coefficient of variation (GCV) were seed yield (20.7), SVI (12.1), and seed emergence speed (10.8), respectively. Traits with high phenotypic coefficient of variation (PCV) included seed yield (36.8), SVI (22.8), and SES (37.5). The presence of variability in all studied traits was evident from both GCV and PCV values. However, PCV values were slightly higher than GCV, suggesting the influence of environmental factors on these traits. Seed yield exhibited high genetic advance (23.9) and intermediate heritability (31.5%), while SES showed low heritability (8.4%) and low genetic advance (6.5), and FGP displayed low heritability (8.3%) and low genetic advance (2.1). High heritability and genetic advance in certain traits indicate the presence of additive gene action, suggesting that these traits can be improved through direct selection. These findings suggest the presence of valuable variations that can be harnessed for AYB genetic enhancement and selection purposes. Our study results offer valuable insights for the genetic improvement, conservation, management, multi-location evaluations, short-term recommendations, and potential release of new AYB genotypes.

Production and Quality Assessment of Custard from Cornstarch Fortified with Roasted African Yam Bean and Solar Dried African Bush Mango

Production and Quality Assessment of Custard from Cornstarch Fortified with Roasted African Yam Bean and Solar Dried African Bush Mango

Amino acid profile and protein quality of starter cultures fermented African Yam bean (Sphenostylis sternocarp) seed condiment

African yam bean seeds condiment is an unpopular nutritive local food seasoning compared to Iru and is mostly produced by natural fermentation. Production with a defined starter culture will give a novel functional condiment with enhanced nutritive values, especially amino acids, to prevent hidden hunger, shorten the fermentation time, and improve product uniformity. The effect of different monoculture bacterial starters and natural fermentation on the amino acids profile of condiments produced from African yam bean seeds was investigated. The result revealed a total of 18 amino acids with glutamic and aspartic acids as the most abundant amino acids in all the samples portions, with a range of values of 9.79-11.44 g/100 g protein and 9.20 -10.67 g/100 g protein respectively. The inoculated samples were rich in all the amino acids quality than un-inoculated. The total amino acid content of the samples was significantly different (p ≤ 0.05). Bacillus amyloliquefacien starter fermented sample had the highest total amino acid value of 95.80 g/100 g protein while Bacillus subtilis fermented and un-inoculated seed portion samples had a total amino acid value of 86.81 g/100g and 74.04 g/100 g protein respectively. The essential amino acids (EAA10) were significantly different (p ≤ 0.05) and were in the range of 35.75-46.32 g/100 g protein with leucine, arginine, lysine, valine, isoleucine and phenylalanine the most abundant in inoculated and un-inoculated samples portions and were more concentrated in inoculated samples. Non-essential amino acids were slightly higher (38.29 - 49.47 g/100 g protein) than the total essential amino acids. The total acidic amino acids varied from 18.99 – 22.11 g/100 g protein and were significantly higher than the basic amino acids (12.88 – 15.95 g/100 g protein). The amino acid content of the Bacillus amyloliquefacien starter fermented sample was better enhanced than the sample fermented with Bacillus subtilis starter. The study concluded that controlled fermented condiments produced with B. amyloliquefacien culture boosted the amino acids value and profile.

Quality Evaluation of Breakfast Cereal Meal Produced from Finger Millet (Eleusine coracana) and Roasted African Yam Beans (Sphenostylis stenocarpa) Flour Blends

This study was carried out to evaluate the qualities of breakfast cereal meals produced from blends of finger millet and toasted African yam beans flour. Flour samples of processed finger millet were blended with roasted African yam beans flour at substitution levels of 0, 10, 20, 30, and 40%. The blended flours were processed into breakfast cereal. The breakfast cereal products were subjected to proximate, vitamin, mineral, and microbial analyses (mould count and total viable count) and sensory evaluation. The result showed that there was a significant increase in the protein, moisture, carbohydrate, and energy content of the breakfast cereals with a corresponding decrease in the ash and fiber content as the level of African yam bean flour increased in the blends. The proximate composition result of the breakfast cereal product ranged from 11.65-37.78% for protein, 13.70-4.91% for ash, 3.00-7.20% for fiber, 2.88-3.88% for moisture, 0.74-1.00% for fat, 46.41-76.77% for carbohydrate and 360.98-380.36% for energy. Vitamin composition of the products ranged from 43.17-72.14 UI for vitamin A, 0.058-0.184 mg/100 g for vitamin B1, 0.058-0.184 mg/100 g for vitamin B2, 0.006-0.015 mg/100 g for vitamin B3 0.289-0.516 mg/100 g. Mineral composition ranged from 6.50-10.01 mg/100 g for iron, 355.53-454.37 mg/100 g for calcium, and 27.65-28.75 mg/100 g for phosphorus content. The total viable count ranged from 2.7 × 102 to 2.8 × 102 cfu/g while the mould was not detected in any of the samples. Results of sensory evaluation showed that FAY60 was the most acceptable breakfast cereal meal.

Utilization of Yam Bean Juice as Nutrient Source for Bacterial Cellulose Production by Komagataeibacter nataicola TISTR 975

Background: Bacterial cellulose has attracted much interest over the years because of its diverse applications stemming from its unique properties. Alternative sources of raw materials for culture medium have become essential to reduce the cost of raw materials and scale up bacterial cellulose production. Objectives: The present study aims to investigate the cellulose-producing ability and characteristics of bacterial cellulose produced by Komagataeibacter nataicola TISTR 975 using yam bean juice as a nutrient source and optimizing the culture medium conditions to produce bacterial cellulose. Methods: Bacterial cellulose was produced by K. nataicola TISTR 975 using yam bean juice as the nutrient source in the culture medium. Fermentation was performed in static culture using 10% inoculum, with varying levels of initial total soluble solids content (8, 10, and 12 °Brix), supplemented with ammonium sulfate (0.1, 0.3, and 0.5 (% w/v)), pH 5.0, 1.4% (v/v) ethanol, and incubated at 30 °C for 10 days. The cellulose membrane was measured for cellulose yield. Physicochemical and sensory characteristics of bacterial cellulose were examined. Results: Initial total soluble solids content at 10 °Brix (equal to the sugar content of approximately 100 g/L) and supplemented with 0.1% (w/v) of ammonium sulfate improved bacterial cellulose yield. Moisture content and water holding capacity (WHC) of bacterial cellulose were high, and L*, a*, and b* values and textural properties were related to perceived sensory characteristics. Sensory evaluation showed the highest score for color and overall acceptability. Conclusion: Local edible yam bean tubers could be used as an alternative raw material for bacterial cellulose production by K. nataicola TISTR 975 using yam bean juice, and bacterial cellulose produced using yam bean juice as a nutrient source has the sensory attributes consistent with the desirable characteristics of raw material for food and processed food products.

Yam Bean (Pachyrhizus erosus L. Urban) Powder Improves Grass Carp Myofibrillar Protein Gel by Forming Disulfide Bonds, Hydrogen Bonds, and Proper Microstructure.

This study aimed to analyze the impact of different additions (0-1.25%) of yam bean powder (YBP) on myofibrillar protein (MP) gel characteristics such as the structure, water-holding capacity (WHC), chemical interaction strength of grass carp MP, and texture. The results showed that the YBP exhibited a strong water absorption capacity and filled in the protein heat-induced polymerization gel network well, which enabled the gel network to capture and retain water effectively, resulting in MP gels containing YBP with excellent WHC and gel strength (0.75%). In addition, YBP induced the formation of hydrogen and disulfide bonds in proteins and inhibited the conversion of α-helices to β-sheets and β-turn structures, facilitating the formation of high-strength gel networks (p < 0.05). In conclusion, YBP can significantly improve the thermally induced gelling properties of grass carp MP. In particular, the addition of 0.75% YBP had the best effect in terms of filling the gel network of grass carp MP, resulting in the formation of a continuous and dense protein network, leading to the composite gel with the best WHC and texture.

Complete Genome Sequence Data of Pseudomonas bijieensis SP1 Associated with Root Soft Rot of Yam Bean.

Pseudomonas bijieensis is a newly established species with antifungal activity. Here, we report the high-quality and complete genome sequence for P. bijieensis strain SP1, created by hybrid assembly using both short reads and long reads. The length of the circular chromosome is about 6.67 Mb, with a GC content of 60.89%. Bioinformatic analyses revealed gene clusters for the biosynthesis of antimicrobial metabolites 2,4-diacetylphloroglucinol as well as bacterial secretion systems (type I to III and type V to VI). Interestingly, this strain can cause soft rot symptoms in the roots of yam bean, showing the potential to be a plant pathogen. The genomic data will be a valuable resource for exploring the virulence mechanism and antifungal activity of this strain.

Nutritional properties of underutilized legumes and intercropped maize

Over the years, intercropping which is majorly carried out on legumes and cereal has been practiced to maximize the utilization of land resources and increase the productivity over a piece of land. Most studies on intercropping focus on the yield and yield parameters, leaving out other important aspects such as the nutritional value of the harvested crops. Underutilized legumes are crops which have very scanty information available on them which reduces their general acceptability and utilization. The effects of intercropping on the nutrient status of underutilized legumes and maize in an intercropping system are not well understood. Therefore, the objective of the research was to assess the effect of intercropping on the nutrient and antinutrient parameters of African Yam Bean (AYB), and Winged bean (WB) when monocropped and when intercropped with maize. Hence, this research sought to answer the following questions: (i) does intercropping with maize affect the nutrient and anti-nutrient properties of AYB and WB (ii) does intercropping with AYB and WB and the application of urea fertilizer affect the nutrient and anti-nutrient properties of maize. Five accessions each of AYB and WB were separately intercropped with two accessions of maize. The research was carried out on the research field of the International Institute of Tropical Agriculture, Ibadan, Nigeria. The field was laid out in a Randomized Complete Block Design in triplicates. The treatment consisted of sole and intercropped legumes and maize as well as maize planted with urea fertilizer. The result from the research revealed that intercropping had effects on the nutrient and anti-nutrient properties of AYB, WB and maize, even though each accession responded differently to the intercropping. For instance, in the legumes, intercropping with M2 led to a reduction in the moisture content of AYB accessions TSs4, TSs30, and TSs77, and an increase in the moisture content in winged bean accession Tpt51. Equally, a reduction in the protein content of African yam bean accessions TSs4 and 101 when intercropped with both maize accessions was observed (P ≤ 0.05). On the other hand, an increase was observed in the protein content of AYB accession TSs30 (intercropped with M2), as well as WB accession 15-4 (intercropped with M2) and Tpt51 (intercropped with M1). A reduced tannin content was observed in WB accession Tpt12 intercropped with both maize accessions, while an increased the tannin content was observed in AYB accessions TSs4, TSs101, and WB accessions 15-4, and Tpt32 when intercropped with both maize accessions (P ≤ 0.05). Finally, intercropping increased the fat content in both maize accessions, increased the tryptophan content of M1 when intercropped with Tpt32, and increased the carbohydrate content in M1 intercropped with Tpt51. In conclusion, the results from this experiment revealed that intercropping affected the nutritional and antinutritional properties of the maize and legumes. Of all the Accessions of the underutilized legumes used, AYB accession TSs30 responded better to intercropping by having a better nutritional value (an increased ash, protein, fat and carbohydrate contents as well as a reduced moisture content); it is therefore necessary to further explore this accession to ensure that the potentials embedded in itis maximally tapped into to enhance food security.

Nutrients, the Bioavailability of Micronutrients and Antinutrient Composition of African Yam Bean Tubers

Despite the huge nutritional and nutraceutical benefits associated with the consumption of African yam bean (AYB) seeds, AYB tubers are still underutilized in Nigeria, they are left to rot in farmers’ fields. To create awareness about their nutrient density and provide information on the bioavailability of micronutrients in the tubers of AYB accessions, raw tubers of TSs 9, TSs 60 and TSs 93 were analyzed using standard laboratory procedures. The AYB tubers had the following composition on a fresh weight basis: crude protein (7.55-8.27%), carbohydrate (9.36-11.12%), crude fat (0.18-0.22%), crude fibre (0.33-0.750%), crude ash (0.44-0.59%), and moisture (79.76-80.82%). The fresh tubers were rich in minerals: potassium (532.88-557.80 mg/100 g), calcium (205.75-467.50 mg/100 g), magnesium (124.75-168.50 mg/100 g), iron (15.71-27.30 mg/100 g), zinc (8.57-14.80 mg/100 g), and manganese (0.68-1.98 mg/100 g). The phytate: Zn and the phytate: Fe molar ratios indicated the bioavailability of Fe and Zn in the raw AYB tubers. The results of this study indicate that AYB tubers are good sources of protein, energy and bioavailable Fe and Zn and should be utilized for human diets and livestock feed. With good processing, AYB tubers could contribute to food and nutrition security. There is a need for research on food products developed from AYB tubers to enhance their utilization and large-scale production in Nigeria.&nbsp

Vacuum Impregnation of Polyphenols in Yam Bean: Effect on Sensory Acceptability, Antioxidant Capacity, and Potential Absorption Ability

The aim of this study was to evaluate the effect of vacuum impregnation (VI) of an ultrasound-assisted mango seed phenolic extract on antioxidant capacity (AOX), phenolic content, proximal composition, sensory acceptability, and in vitro polyphenols potentially available for absorption (PPAA) in the yam bean slice. The final parameters of VI optimizations by response surface were: slice thickness (1.5 mm), vacuum time (15 min), and restoration time (5 min). The optimal treatment (OT) showed a 412% increase in total soluble polyphenols (TSP), as well as a general increase in DPPH, ABTS, and FRAP (20.26, 129.99, and 64.52 μmol TE/g respectively), in relation to the control. However, VI increased the amount of nonextractable polyphenols in the indigestible fraction of yam bean slices and reduced the PPAA compared to the control. Therefore, it is concluded that the application of VI increases TSP and AOX, maintains sensory parameters, and decreases the PPAA in yam bean.

Nutritional, functional, and bioactive properties of african underutilized legumes.

Globally, legumes are vital constituents of diet and perform critical roles in maintaining well-being owing to the dense nutritional contents and functional properties of their seeds. While much emphasis has been placed on the major grain legumes over the years, the neglected and underutilized legumes (NULs) are gaining significant recognition as probable crops to alleviate malnutrition and give a boost to food security in Africa. Consumption of these underutilized legumes has been associated with several health-promoting benefits and can be utilized as functional foods due to their rich dietary fibers, vitamins, polyunsaturated fatty acids (PUFAs), proteins/essential amino acids, micro-nutrients, and bioactive compounds. Despite the plethora of nutritional benefits, the underutilized legumes have not received much research attention compared to common mainstream grain legumes, thus hindering their adoption and utilization. Consequently, research efforts geared toward improvement, utilization, and incorporation into mainstream agriculture in Africa are more convincing than ever. This work reviews some selected NULs of Africa (Adzuki beans (Vigna angularis), African yam bean (Sphenostylis stenocarpa), Bambara groundnut (Vigna subterranea), Jack bean (Canavalia ensiformis), Kidney bean (Phaseolus vulgaris), Lima bean (Phaseolus lunatus), Marama bean (Tylosema esculentum), Mung bean, (Vigna radiata), Rice bean (Vigna Umbellata), and Winged bean (Psophocarpus tetragonolobus)), and their nutritional, and functional properties. Furthermore, we highlight the prospects and current challenges associated with the utilization of the NULs and discusses the strategies to facilitate their exploitation as not only sources of vital nutrients, but also their integration for the development of cheap and accessible functional foods.

Studies on the Quality Characteristics of Flour Blends from Sesame Seeds, African Yam Bean and Moringa Leaf Powder for “Biscuit- Like” Manufacture

This study was aimed at investigating the quality characteristics of flour blends produced from sesame seeds, African yam bean (AYB) and Moringa leaf powder (MLP) for “biscuit- like” production. Dehulled sesame seeds were roasted for 7-13 min at 185 – 200 0C, defatted and milled into flour and tagged as DSDSF , African yam bean was toasted at 125 0C for 40 min, dehulled, milled into flour, and tagged as TDAYBF while Moringa leaf was sundried, milled into flour and tagged as MLP. All these flour samples were then blended into 18 ratios and tagged as LMDTM1-18. The ratios of DSDSF:TDAYBF:MLP were 100: 0:0(LMDTM1), 0: 100: 0(LMDTM2), 95: 0: 5(LMDTM3), 95:5:0(LMDTM4), 90: 5:5(LMDTM5), 90:10:0(LMDTM6), 80:15:5 (LMDTM7), 80: 20:0(LMDTM8), 70:25: 5(LMDTM9), 70:30: 0(LMDTM10), 60: 35: 0(LMDTM11), 60: 40: 0(LMDTM12), 50: 45: 5(LMDTM13), 50: 50: 0(LMDTM14), 40: 55: 5(LMDTM15), 40: 60: 0(LMDTM16), 30: 65: 5(LMDTM17), and 30: 70: 0(LMDTM18). The flour blends were studied for physicochemical, functional and anti-nutrients properties. After blending, the formulated samples had proximate composition of 3.37 -9.21 % moisture, 18-27.5 % protein, 0.18-3.95 fat, 1.31 – 3.9 % ash, 3.2-8.88 % crude fiber and 52.75-65.45 % carbohydrate. Each proximate component varied significantly (p&lt;0.05) between samples. While LMDTM13 had significantly(p&lt;0.05) the highest moisture content, protein, and fat LMDTM6 had the highest ash content, LMDTM2 had the highest crude fiber and LMDTM1 had the highest carbohydrate. The control sample LMDTM1 had the highest bulk density (0.711), water absorption capacity (165.52 %), oil absorption capacity (94.5 %), protein solubility (13.4 %), foaming capacity (8.0 %), but lowest swelling power (3.5 %), emulsion capacity (46.2 %), phytate (16.29 mg/100g), tannin (4.64mg/100g) and Trypsin inhibitor (1.20 mg/100g) compared to other samples. Blended flour mainly from plant sources of high-quality value can be blended when processed, giving the opportunity to increase its nutrition, consumption, and acceptability for biscuit- like production. In this study, sesame seeds were incorporated into African yam bean and moringa leaf powder to increase the quality and flavor replacing wheat flour in biscuit production.

EFFECT OF SHOOT PRUNING INTERVAL AND DOSAGE OF POTASSIUM FERTILIZER ON GROWTH AND YIELD OF YAM BEAN (PACHYRHIZUS EROSUS L.)

A study was conducted in Baratan village, district of Patrang, Jember, East Java, on the effects of shoot pruning intervals and potassium fertilizer dosages on the growth and yield of yam bean (Pachyrhizus erosus L.). Pruning of the plant shoot was done six weeks after planting, 50 cm above the soil surface. Three levels of shoot pruning treatment were: no pruning (control), shoot pruning every 7 days, and shoot pruning every 14 days. The dosages of potassium fertilizer were: 0, 75, 150, 225, and 300 kg ha1 of K2O. The experimental design adopted was the completely randomized block design (CRBD) with three replications. The results showed that pruning of shoots every 7 days with potassium fertilizer at 225 kg ha-1 gave the best effect on leaf area index, tuber diameter, tuber fresh weight, tuber dry weight, and total plant fresh weight and dry weight, respectively. Those values were 6.1; 18.88 cm; 468.56 g, 89.05 g, 710.32 g, and 143.54 g, respectively. There was an increase of 289, 175, 392, 362, 247, and 223 percent again without pruning and potassium fertilizer (control) treatments. Pruning shoots every 7 days with 300 kg ha-1 potassium fertilizer resulted in the highest tuber carbohydrate content, which was 44.99 percent higher than the control treatment (no pruning and potassium fertilizer application).

A Preliminary Evaluation of Variability, Genetic Estimates, and Association among Phenotypic Traits of African Yam Bean Landraces from Ghana

A field experiment was conducted at the Research and Teaching Farm, School of Agriculture and Technology (SOAT), University of Energy and Natural Resources (UENR), Dormaa Ahenkro Campus, Ghana, to determine the genetic variability, heritability, genetic advance, and correlation among growth and yield traits of the African yam bean in Ghana. There were significant differences ( p &lt; 0.05 ) for the traits studied, except for days to 50% emergence, petiole length, days to maturity, stem diameter, days to 50% flowering, pod weight, pod beak length, pod weight per plant, seed length, and seed width. The phenotypic coefficient of variation and genotypic coefficient of variation for the yield and yield components ranged from 9.43% to 18.92% and 3.25% to 15.93%, respectively, and from 9.35% to 20.08% and 2.15% to 23.28%, respectively, for the growth parameters. Heritability ranged from 34.54% to 91.81, and the GAM ranged from 2.77% to 45.96% for the growth parameters. The heritability and GAM for the yield parameters ranged from 11.85% to 73.56% and 1.94% to 27.64%, respectively. The correlation analysis revealed a positive and highly significant ( p &lt; 0.001 ) relationship between petiole length and leaf length (r = 0.573), number of seeds per pod and number of leaves (r = 0.520), pod beak length and peduncle length (r = 0.560), pod weight per plant and pod weight per plot (r = 0.971), seed weight per plant and 100 seed weight (r = 0.967), grain yield and 100 seed weight (r = 0.999) and seed weight per plant (r = 0.970), 100 seed weight and pod per plant (r = 0.576). The study revealed diversity among the AYB landraces collected, which provides an opportunity for improvement of the African yam bean in Ghana. There is the need for the conservation of these landraces for further evaluations and the improvement of the promising landraces and traits through breeding programmes.

Mitotic studies, pollen fertility and morphological response of African yam bean (Sphenostylis stenocarpa (Hochst. ex A. Rich) Harms) to gamma radiation

Mitotic studies, pollen fertility and morphological response of African yam bean (Sphenostylis stenocarpa (Hochst. ex A. Rich) Harms) to gamma radiation

First report of bean common mosaic virus naturally infecting yam bean (Pachyrhizus erosus) in China.

Yam bean (Pachyrhizus erosus), a high-yielding leguminous root crop with good nutritional value, is widely cultivated in southern China. In 2020, P. erosus (cv. Mumashan) plants exhibiting irregular yellow leaves and malformed seed pods (Supplementary Fig S1) were observed at Ningbo city, Zhejiang Province, China. To determine the causal agent(s) of the disease, symptomatic leaves (n=4) were collected for electron microscopy negative staining. Virus particles with a length of about 700nm, similar to viruses in the genus Potyvirus, were observed via transmission electron microscope (TEM), suggesting the presence a potyvirus(es). To further confirm which potyvirus(es) infected yam bean, total RNA was extracted from leaf samples of a total of six plants, including four symptomatic plants and two asymptomatic plants using TRIzol reagent (Invitrogen Carlsbad, CA, USA) according to the manufacturer's instructions. RNA was reverse-transcribed into cDNA with M4-T as the 3'-anchoring primer by ReverTra Ace® kit (Toyobo, Japan). Sprimer/M4 Potyviridae specific primers (Chen et al., 2001) were used for PCR analysis. A ~1,700-bp-long product was amplified from four symptomatic plants using KOD FX enzyme (Toyobo, Japan). No such band was amplified from the two asymptomatic plants. The PCR product (~1.7kb) amplified from a single symptomatic plant was ligated into the pEASY®-Blunt Zero vector (TransGen Bio, Beijing, China) and sequenced (Sangon Bio, Shanghai, China). The amplicon showed 99% nucleotide sequence identities with bean common mosaic virus (BCMV) isolate NKY021 (KJ807819). Subsequently, the complete nucleotide sequences of this BCMV isolate (referred as BCMV-NB) was amplified by overlapping RT-PCR and rapid amplification of cDNA ends with primers (Supplementary Table S1) designed from the sequence of BCMV isolate NKY021. The BCMV-NB full genome (Accession No. OL871237) consists of 10,053 nucleotides excluding the poly(A) tail and contains a large open reading frame encoding a polyprotein of 3222 amino acids. BLASTn analysis showed that BCMV-NB shared a sequence identity of 96.4% with BCMV isolate HZZB011 (KJ807815). Phylogenetic tree generated by Neighbour-Joining method revealing the BCMV-NB isolate was grouped together with Chinese isolates from Glycine max (Supplementary Fig S1). To test the infectivity of BCMV-NB, virus-free yam bean (cv. Mumashan) and Nicotiana benthamiana seedlings were mechanically inoculated with sap extracted from the symptomatic leaves of a BCMV-NB-infected yam bean plant. The inoculated yam bean plants developed typical BCMV mosaic and chlorotic symptoms at 16 days post inoculation (dpi), while Nicotiana benthamiana had no obvious symptoms at 10 or 20 dpi (Supplementary Fig S1). BCMV infections were confirmed in yam bean plants (infection rate 6/6) and N. benthamiana plants (infection rate 8/8) by RT-PCR at 16 dpi and 10 dpi, respectively. Twelve further P. erosus plants (cv. Mumashan) were collected from a field in Ningbo city and tested by RT-PCR with BCMV-specific primer pair BCMV CP (+)/(-) (Supplementary Table 1). Eight out of the 12 samples tested positive for BCMV by PCR-gel electrophoresis (Supplementary Fig S1) and Sanger sequencing, suggesting a high incidence of BCMV infection in this field. BCMV infection in yam bean has been reported from Indonesia (Damayanti et al., 2008) and Peru (Fuentes et al., 2012). To the best of our knowledge, this is the first report of BCMV naturally infecting yam bean in China. Thus, special attention and appropriate management strategies are needed to minimize the damage caused by BCMV to yam bean crops in China.

Nutritional analysis of african yam bean and bambara nut pudding

This study was to analyze and compare the nutritional contents of African yam bean pudding and Bambara nut pudding. Many important crop plants native to Africa with the potential to alleviate and reduce food insecurity in the continent are severally neglected, unimproved and under-utilized. It is of great importance to examine the nutrient, toxic substance, and anti-physiological substance composition of locally available foods in a community or country. The result of the proximate analysis showed that BNP had higher moisture content, crude fat, and protein compared to AYBP, and its statistically not significant P ≥ 0.05, BNP showed a significantly higher carbohydrate compared to AYBP P≤ 0.05. The ash and fiber content of AYBP was shown to be statistically higher than that of BNP with P≤ 0.05. The result of the vitamin analysis showed that AYBP had significantly higher vitamin C compared with BNP, and vitamin A though not significant. The vitamin E content of both puddings was shown to be equal. The outcome of the analysis showed that AYBP is rich in fiber and low in carbohydrates as such could be a meal for diabetic patients. The vitamins contained in AYBP make it a requirement for school children and could be a source of a cheap source of vitamins to the rural and low-income earners in our society. AYBP has longer shelf life compared with the BNP because of its low moisture content.

FUNCTIONAL, PASTING AND SENSORY PROPERTIES OF COMPLEMENTARY FOOD FROM ORANGE FLESHED SWEETPOTATO- ROASTED AFRICAN YAM BEAN-TIGERNUT COMPOSITE FLOUR USING RESPONSE SURFACE METHODOLOGY

This study investigated the functional, pasting and sensory properties of complementary food from blends of orange fleshed sweet potato, roasted African yam bean and tigernut composite flour using response surface methodology. Orange fleshed sweetpotato root, roasted African yam bean and tigernut seed were blended into composite flours based on D-optimal mixture design resulting into fourteen experimental runs. The Orange fleshed sweetpotato, roasted African yam bean and tigernut flour blends were analyzed for their functional and pasting properties using standard laboratory procedures. The composite flours were optimized using D-optimal of the mixture design. The optimized composite flours were used to prepare complementary food and sensory properties (taste, colour, aroma, thickness and overall acceptability) were evaluated using nine point Hedonic scale of preference. The bulk density, water absorption capacity, swelling power, dispersibility, least gelation capacity and wettability ranged from 0.82-0.85g/ml, 300.00-359.00%, 6.00-6.51%, 60.20-65.99%, 2.72-3.69% and 22.71to 40.81% respectively. Significant differences (p&lt;0.05) were observed in the pasting properties of orange fleshed sweetpotato, roasted African yam bean and tigernut flour blends. However optimized complementary prepared from the different composite flours were all accepted by the panelists except complementary food prepared from 82.95% orange fleshed sweetpotato, 10.26% roasted African yam bean and 6.78% tigernut composite flour blend.

Genome-Wide Association Study Revealed SNP Alleles Associated with Seed Size Traits in African Yam Bean (Sphenostylis stenocarpa (Hochst ex. A. Rich.) Harms).

Seed size is an important yield and quality-determining trait in higher plants and is also crucial to their evolutionary fitness. In African yam bean (AYB), seed size varies widely among different accessions. However, the genetic basis of such variation has not been adequately documented. A genome-wide marker-trait association study was conducted to identify genomic regions associated with four seed size traits (seed length, seed width, seed thickness, and 100-seed weight) in a panel of 195 AYB accessions. A total of 5416 SNP markers were generated from the diversity array technology sequence (DArTseq) genotype-by-sequencing (GBS)- approach, in which 2491 SNPs were retained after SNP quality control and used for marker-trait association analysis. Significant phenotypic variation was observed for the traits. Broad-sense heritability ranged from 50.0% (seed width) to 66.4% (seed length). The relationships among the traits were positive and significant. Genome-wide association study (GWAS) using the general linear model (GLM) and the mixed linear model (MLM) approaches identified 12 SNP markers significantly associated with seed size traits across the six test environments. The 12 makers explained 6.5-10.8% of the phenotypic variation. Two markers (29420334|F|0-52:C>G-52:C>G and 29420736|F|0-57:G>T-57:G>T) with pleiotropic effects associated with seed width and seed thickness were found. A candidate gene search identified five significant markers (100026424|F|0-37:C>T-37:C>T, 100041049|F|0-42:G>C-42:G>C, 100034480|F|0-31:C>A-31:C>A, 29420365|F|0-55:C>G-55:C>G, and 29420736|F|0-57:G>T-57:G>T) located close to 43 putative genes whose encoding protein products are known to regulate seed size traits. This study revealed significant makers not previously reported for seed size in AYB and could provide useful information for genomic-assisted breeding in AYB.