Development of micropropagation system for yam (Dioscorea spp.) using somatic embryogenesis

Inadequate availability of disease-free planting materials remains a major constraint to yam production. The tissue culture technique has been used to regenerate disease-free plantlets from pre-formed, heattreated meristems followed by micropropagation. This procedure, however, has a low multiplication ratio with an average of 1: 4 every eight weeks. Embryo production from somatic cells (somatic embryogenesis, SE) is a system in which each somatic cell can regenerate a complete plantlet. However, previous reports show low SE induction frequencies and significant variations in success rates among different genotypes while hardly any report exist for improved varieties that farmers desire, especially in Nigeria. Studies were carried out to evaluate the effects of different plant growth regulators (PGRs) on induction of somatic embryogenesis of the following genotypes: one improved Dioscorea alata (TDa 291) and three improved (TDr 95/19177, TDr 89/2665, TDr 95/18544) and one landrace (Obioturugo) of Dioscorea rotundata. Leaf, stem, and axillary bud explants were cultured in MS basal medium containing fifteen treatment combinations of 2,4-Dichlorophenoxyacetic acid (2,4-D), Naphthaleneacetic acid (NAA), Benzylaminopurine (BAP), Picloram, and Uniconazole-P (UP). The genotype TDr 95/19177 was tested for SE in Temorary Immersion Bioreactor System (TIBS). The incidence of induction of callus formation and plantlet regeneration from the three explants were recorded. Embryogenic callus induction was highest (87%) from axillary buds cultured on modified MS + 2 mg/l of 2,4-D + 1 mg/l of NAA while 1 mg/l of BAP + 9. 9 mg/l of UP had the highest percentage plantlet regeneration of 50% in TDr 95/18544 and an average of 37% across genotypes at a mean of 5 plantlets per explant. The genotype TDr 95/19177 was successfully regenerated via indirect somatic embryogenesis in the SETIS Type Temporary Immersion Bioreactor System

Upscaling cassava processing machines and products in Liberia

Open Access JournalCassava is produced by more than 80% of farming households and is an important contributor to gross domestic product (GDP) in Liberia. It is therefore important to assess the status of cassava processing into food and other products. A total of one hundred and sixty (160) well-structured questionnaires were used for the collection of information from eight counties, with twenty respondents from each county. It was found out that all the counties lack adequate modern cassava processing machines, with almost all cassava processing operations being done with rudimentary equipment. Gari and wet fufu are common products in Liberian markets, with no high-quality cassava flour (HQCF) or derivatives. Consequently, user and gender friendly processing machines were installed in six established modern cassava processing centres, and new cassava products, such as fufu powder, tapioca, and HQCF with its value-added products (10% bread and pastries), were introduced. This upscaling will enhance the cassava value chain in Liberia with improvement in livelihoods, especially for vulnerable women and unemployed youth

Assessment of the suitability of different cassava varieties for gari and fufu flour production in Liberia

Open Access Article; Published online: 15 Feb 2020Different cassava varieties are available in Liberia, but there is little knowledge of their product suitability. Hence, the need to assess the potentials of these varieties to produce gari and fufu flour. The two products from ten improved and two local cassava varieties were characterized based on their yield and chemical, pasting and functional properties using standard methods. The results showed that TMS 96/0097 (gari 27.54%) and Butter cassava (fufu flour 27.35%) have the highest percentage yields. The starch content was higher in gari produced from TMS98/0505 (92.00%) and lower from TMS95/0289 (82.62%); the fufu flour starch content was higher in TMS98/0505 (90.59%) and lower in Bassa girl (84.75%). Gari and fufu flour produced from TMS96/0097 (507.38 RUV) and TMS00/0357 (506.04 RVU) had the highest final viscosity, and the products from TMS95/0289 (338.46 RVU and 336.80 RVU) had the least. The highest swelling power was found in gari (12.74%) and fufu flour (13.55%) produced from TMS92/0057 and the lowest in TMS91/0416 gari (8.23%) and TMS01/1235 fufu flour (8.31%). All the samples may form a paste below the boiling point of water (100°C) at < 7 min. However, cassava varieties and the interactions between varieties and locations had a significant (P < 0.05) effect on the properties of the products: Chemical (except ash content), pasting (except pasting temperature) and functional. Therefore, all the varieties may be suitable for gari and fufu flour production based on the quality preferred by the consumers

Incidence and diversity of mixed viruses lower in yam tubers and tuber sprouts compared with field leaf samples: Implications for virusfree planting material control strategy

Millions of people around the world, particularly in West Africa, depend on yam for food and income, however global yam production has been fluctuating since 2007. Virus infections contribute to yam yield losses and the occurrence of mixed virus infections is potentially catastrophic. Planting of certified virus-free/resistant tubers is advocated therefore knowledge of the role of yam planting material in the virus dynamics in yam fields is crucial for effective yam virus control. In this study, yam tubers bought from markets in six West African countries were planted in an insect proof screen-house. Leaf samples from the tuber sprouts were tested by ELISA and/or IC-PCR/IC-RT-PCR to determine the incidence of Yam mosaic virus, Yam mild mosaic virus, cucumber mosaic virus, and Dioscorea Bacilliform viruses. Yam tubers from Nigeria and Ghana, as well as yam leaves collected from yam fields in Nigeria were also tested. All the viruses assayed for were detected. Most of the virus infections detected in the tuber (83%) and tuber sprouts (95%) were single infections of either Dioscorea bacilliform viruses (DBV) or Yam mosaic virus (YMV). The incidence of mixed infection in the field samples (49.3%) was about 3 times and 10 times more than those detected in the tubers (17%) and the tuber sprouts (5%). These results suggest that other factors other than the tubers used as planting materials contribute to the vast incidence of mixed virus infections in yam fields. These factors must be properly appraised and be factored into any yam virus control strategy equation in order to achieve a sustainable yam production in West Africa in particular and the world in general

Harnessing modern biotechnology for tropical tuber crop improvement: Yam (Dioscorea spp.) molecular breeding

Yams (Dioscorea spp.) constitute a staple food crop for over 100 million people in the humid and subhumid tropics. They are polyploid and vegetatively propagated. The Guinea yams, Dioscorea rotundata and D. cayenensis, are the most important yams in West and Central Africa where they are indigenous, while D. alata (referred to as water yam) is the most widely distributed species globally. The genetics of yams is least understood among the major staple food crops due to several biological constraints and research neglect. Research to unravel the apparent complexity of the yam genome will have far-reaching implications for genetic improvement of this important tuber crop. Some progress has been made in recent years in germplasm characterization and the development of molecular markers for genome analysis. A genetic linkage map based on amplified fragment length polymorphism (AFLP) markers has been constructed for Guinea and water yams. These linkage maps were used to scan the genome for quantitative trait loci (QTL) associated with genes conferring resistance to Yam Mosaic Virus (YMV) in D. rotundata and anthracnose (Colletotrichum gloeosporioides) in D. alata. In addition, candidate random amplified polymorphic DNA (RAPD) markers associated with major genes controlling resistance to YMV and anthracnose have been identified that could be used for selection and pyramiding of YMV and anthracnose resistance genes in yam improvement. Also, molecular markers such as RAPDs, AFLPs, and microsatellites or simple sequence repeats (SSRs) have been developed for yam genome analysis. An initial c-DNA library has been constructed in order to develop expressed sequence tags (ESTs) for gene discovery and as a source of additional molecular markers. This paper will review the advances made, discuss the implications for yam genetic improvement and germplasm conservation, and outline the direction for future research. Key words: Genetic mapping, genome analysis, molecular breeding, PCR-based markers, QTLs, resistance genes, yam. African Journal of Biotechnology Vol. 2 (12), pp. 478-485, December 200

Acceptability of chicken powder in home prepared complementary foods for children in Ghana

The persistent problem of childhood malnutrition and growth faltering in sub-Saharan African countries such as Ghana despite food aid intervention programs, suggests rethinking of the content and mode of delivery of such food programs. While several food programs and formulations exist for the treatment and management of childhood malnutrition, most are neither culturally appropriate nor easily accessible to families at the household level. There is, therefore, a need for a food product that can be tailored to a particular culture and local food produce which provides the necessary macronutrients and micronutrients in adequate amount and is easy to use at the household level to prevent malnutrition. The aim of this study was to evaluate the acceptability of incorporating chicken powder into the  Ghanaian child’s everyday meal. Participants in the study included mothers and their pre-school age children. The chicken powder was incorporated into a breakfast meal (“Tom Brown”) and lunch/supper meal (rice and gravy) on weight basis according to predetermined proportions of the raw  ingredients. Each meal consisted of a control sample (not containing chicken powder) and 3 test samples containing different amounts of chicken powder (15%, 20% and 25% by weight). Overall, both mothers and children rated both control samples highest compared to their respective test sample for preference. Interestingly, mothers were able to tell the differences in the test samples, but the children could not tell the  difference between the test samples by the content of the chicken powder according to the results of the test for homogeneity. The results from the acceptability test as well as individual observation by the research team suggest that chicken powder can be used as animal source protein in the treatment and management of malnutrition by incorporating it into  common staple foods. According to findings of this study, parents are more likely to incorporate the chicken powder (an animal source quality protein) in their children’s diet, if not for the entire family. The incorporation of chicken powder into complementary foods will improve the nutritional value, especially the protein and micronutrient content.Key words: Chicken, Acceptability, Ghana, Malnutrition, Feedin

Anaemia, vitamin-A deficiency, anthropometric nutritional status and associated factors among young school children in Kodzobi, Ghana, a peri-urban community

Anaemia, vitamin-A deficiency and under nutrition are prevalent among children at levels of public health significance in developing countries of which Ghana is no exception. The objective of this study was to assess the anaemia, low vitamin-A level and anthropometric nutritional status of 162 randomly selected young Ghanaian school children 4 – 8 years in Kodzobi, a peri-urban community and establish associated factors. Questionnaires were used to collect background data from parents of study participants. Vitamin-A and haemoglobin concentrations were determined using High Performance Liquid Chromatography and Haemocue hemoglobinometer, respectively. Malaria parasitaemia was examined by the Giemsa staining technique. Weight and height measurements were taken according to WHO’s standard procedures to assess participants’ nutritional status. The mean haemoglobin and serum retinol concentrations were 11.6 ± 1.1 g/dl and 22.8 ± 6.5 μg/dl, respectively. Prevalence of anaemia and vitamin-A deficiency among study participants were 38.3 % and 24.0 %, respectively. The prevalence of underweight, stunting, thinness and overweight were 9.3 %, 9.9 %, 4.3 % and 3.7 %, respectively. Haemoglobin correlated positively and significantly with weight, weight-for-age and body mass index-for-age z scores. Child’s sex, vitamin-A status and parental monthly income associated with anaemia status. Females had a higher risk of being anaemic compared to males (OR = 2.519; 95 % CI: 0.965 - 6.580; p = 0.049). Participants with normal vitamin-A concentration were at lower risk of being anaemic (OR = 0.302; 95 % CI: 0.109 - 0.840; p = 0.022) than those with low vitamin-A concentration. Anaemia and young child age negatively associated with vitamin-A status, at p = 0.039 and p = 0.037, respectively. Anaemia and vitamin-A deficiency are issues of public health importance among school-aged children in Ghana. There is, therefore, the need to invest in actions that prevent their occurrence and management especially among children of school going age.Keywords: Anaemia, vitamin-A deficiency, nutritional status, retinol, haemoglobin, school children, peri-urba