Shimelis Hussein

The Potential of Orange-Fleshed Sweet Potato to Prevent Vitamin A Deficiency in Africa

PURPOSE Vitamin A deficiency is among major health problems worldwide that leads to blindness, retarded growth and death, particularly in developing countries. In these countries, vitamin A deficiency largely affects pre-school children, pregnant and lactating mothers, and the rural poor. For instance, the predicted prevalence of vitamin A deficiency for 36 sub-Saharan African countries is 19.1%. METHODS Different strategies, including vitamin A supplementation, food fortification and dietary diversification, have been used to combat this problem. However, these strategies are not sustainable due to their high costs. RESULTS Orange-fleshed sweet potato (Ipomoea batatas L. Lam) is a low priced crop, which is part of staple foods in most of sub-Saharan Africa that can be a year-round source of vitamin A. Most of the orange-fleshed sweet potato varieties contain 3000-16000 μg 100 g(-1) of β-carotene and this contributes to 250 to 1300 μg 100 g(-1) Retinol Activity Equivalents (RAE). Therefore, by using orange-fleshed sweet potato, it is possible to improve vitamin A status, increase the bio-availability of different micro-nutrients such as Fe, Zn, Ca and Mg, reduce vitamin A deficiency and hence reduce child mortality rates by 23 to 30%. CONCLUSION The article highlights the significance of vitamin A for human nutrition, the effect of vitamin A deficiency, the different prevention methods and the potential of orange- fleshed sweet potato as a food crop to prevent vitamin A deficiency.

Technology generation to dissemination: lessons learned from the tef improvement project

Indigenous crops also known as orphan crops are key contributors to food security, which is becoming increasingly vulnerable with the current trend of population growth and climate change. They have the major advantage that they fit well into the general socio-economic and ecological context of developing world agriculture. However, most indigenous crops did not benefit from the Green Revolution, which dramatically increased the yield of major crops such as wheat and rice. Here, we describe the Tef Improvement Project, which employs both conventional- and molecular-breeding techniques to improve tef—an orphan crop important to the food security in the Horn of Africa, a region of the world with recurring devastating famines. We have established an efficient pipeline to bring improved tef lines from the laboratory to the farmers of Ethiopia. Of critical importance to the long-term success of this project is the cooperation among participants in Ethiopia and Switzerland, including donors, policy makers, research institutions, and farmers. Together, European and African scientists have developed a pipeline using breeding and genomic tools to improve the orphan crop tef and bring new cultivars to the farmers in Ethiopia. We highlight a new variety, Tesfa, developed in this pipeline and possessing a novel and desirable combination of traits. Tesfa’s recent approval for release illustrates the success of the project and marks a milestone as it is the first variety (of many in the pipeline) to be released.

Soil acidity under multiple land-uses: assessment of perceived causes and indicators, and nutrient dynamics in small-holders’ mixed-farming system of northwest Ethiopia

ABSTRACT Knowledge on farmers’ perspectives is of paramount importance in order to design appropriate agricultural research and development interventions attuned to local farming systems. A participatory rural appraisal was conducted in order to understand perceived causes and indicators of soil acidity under multiple land-uses in three Districts of northwest Ethiopia. Soil samples were also collected from five dominant land-uses. The samples were analysed for soil pH, exchangeable acidity and other physico-chemical properties. The result indicated that the pH(H2O) of most of the soils in the study sites were in a strongly acidic range (4.6–5.5). Gashena Akayita of the Banja District was the most acidic of all. Among the land-uses, eucalyptus fields were the most acidic followed by crop outfields and grazing lands in that order. At all the study sites, exchangeable Al was detected in soils having a pH of less than 5.0. Overall, the nutrient dynamics showed variation across land-uses and study sites. Farmers’ perceived causes of soil acidity included: soil erosion; contending use of fertility replenishing local resources; abandoning traditional fertility management practices and minimal use of external inputs. The farmers attributed the exclusive use of acid-forming inorganic fertilizers to exhaustion of the soil. Various land and soil characteristics, plant growth attributes, changes in genetic diversity were mentioned as indicators of soil acidity. Particularly, the farmers used prevalence of acidophilic weed species on crop fields and grazing lands as marker of strongly acidic soil. Farmers’ perceived causes and indicators were in agreement with scientific facts and can be utilized as input in designing sustainable acid soil management strategies. Decline in genetic diversity of the once widespread crop species and land races, and expansion of newly introduced soil acidity tolerant species, suggests the need to undertake rescue collections in these areas.

Diagnostic assessment of sweetpotato production in Ethiopia: Constraints, post-harvest handling and farmers’ preferences

Production and post-harvest handling of sweetpotato are constrained by many factors. The objective of the study was assessing and documenting the major constraints affecting production, pre- and post-harvest handling and farmers’ preferences for sweetpotato in Ethiopia. It was conducted in three selected major sweetpotato growing zones in Ethiopia using a participatory rural appraisal methodology. The identified production constraints were heat and drought at 21.6%, shortage of planting materials (20.1%), shortage of land (15.7%), diseases (10.0%), insect-pests (9.4%), a lack of draft power (8.1%), shortage of money (7.9%), a lack of labour (5.1%) and weeds (2.0%). Poor access to markets at 22.6%, poor market prices (19.1%), low yields (14.2%), low root dry matter content (13.6%), a lack of knowledge on processing (11.7%), a lack of processing equipment (11.1%) and transportation problem (7.7%) were identified as the major post-harvest constraints. The major farmers’ selection criteria for sweetpotato varieties were resistance to heat and drought (19.6%), dry matter content (16.4%), taste (14.3%), root yield (13.6%), resistance to disease and insects (13.3%), earliness (11.6%) and cookability (8.9%). Results of this study can serve as a baseline reference for strategic breeding and other interventions to develop sweetpotato varieties according to the needs of the farmers.

Analysis of Biochemical Composition of Yams ( Dioscorea spp.) Landraces from Southwest Ethiopia

Yams make a significant contribution to food security and medicinal importance in developing countries. In Ethiopia, there is insufficient scientific study on biochemical composition of Ethiopian yams. In order to fill the knowledge gap, this study was conducted to assess the biochemical composition of yams collected from Southwest Ethiopia. Flour from storage tuber of 36 yam landraces collected and the samples run in duplicates. Data on 14 biochemical traits were collected and subjected to various data analysis. Results of the analysis of variance indicated significant variation (p<0.01) among the landraces on organic matter, total nitrogen, protein, fat, carbohydrate, total phosphorus, total energy, tannin and saponin contents. The flour moisture contents ranged from 17.75 to 27.47% with a mean of 22.03%. The ranges of dry matter (15.80 to 27.28%), organic matter (21.38 to 43.56%), ash (1.13 to 3.56%), organic carbon (0.63 to 1.98 g), crude fiber (0.41 to 2.05%), total nitrogen (1.00 to 1.32%), protein (6.25 to 8.28%), fat (0.09 to 0.65%), carbohydrate (12.71 to 33.94%), total phosphorus (23.7 to 53.0 mg/100 g), total energy (92.66 to 173.30 kcal/100 g DM), tannin (19.80 to 181.0 mg/100 g) and saponin (2.31 to 13.94 mg/100 g) contents. The cluster and distance analysis of biochemical traits showed the existence of eight divergent groups. The maximum inter cluster distance was found between clusters VI and VII (133.59), followed by clusters V and VI (109.19), clusters II and VI (105.22), clusters I and VI (100.42), and clusters III and VI (89.25) in order of magnitudes. Maximum genetic divergence between the clusters points out the fact that hybridization among the landraces included with them would produce potential and meaningful hybrids and desirable segregants. Besides, investigation of the existed yam landraces based on molecular marker analysis is vital for better assessment of genetic diversity of yams in Ethiopia.

Key maize production constraints and farmers’ preferred traits in the mid-altitude maize agroecologies of northern Tanzania

Maize productivity in Tanzania is very low, owing to various biotic and abiotic production constraints. Examining production constraints and farmers’ preference in maize-growing agroecologies will assist in designing improvement strategies based on farmers’ priorities. The objective of this study was to determine farmers’ preferred traits of maize and prioritise farmers’ perceived constraints that limit potential maize production in northern Tanzania. Twelve maize-growing villages from Babati, Arumeru and Hai districts were surveyed using participatory rural appraisal, involving a total of 500 farmers across the study area. Data collected were analysed using a semi-structured questionnaire, focus group discussions, transect walks, matrix scoring and pair-wise ranking. The most preferred traits were high yield (71.9%), disease resistance (70.0%), drought tolerance (69.9%), good grain milling quality (65.3%), grain palatability (60.7%), dense grain (59.0%) and early maturity (55.8%). Other important traits were large grain size, intercropping suitability, large cob size, storage pests’ resistance and multiple ears. Major biotic and abiotic constraints limiting maize production are identified. The results of this study will assist breeders in defining their maize breeding strategies.

Genotype-by-environment interaction and stability of sweetpotato genotypes for root dry matter, β-carotene and fresh root yield

Abstract The study was conducted to estimate the magnitude of genotype x environment interactions (G x E) and to select stable and high yielding sweetpotato genotypes for root dry matter content (RDMC), β-carotene content and fresh root yield, and to identify the most discriminating and representative test environments in Ethiopia. The study was conducted across six environments (Halaba, Kokate, Areka, Arbaminch, Hawassa and Dilla) in southern Ethiopia. Twenty four selected genotypes and one check variety (Tula) were evaluated using a 5 × 5 simple lattice design. Stability analysis was conducted using Genotype plus Genotype by Environment Interaction (GGE bi-plot). Environment, genotype and G × E interaction variances were significant (p < 0.001) for the three traits. The magnitude of environment and G x E interaction was 66.8% for fresh root yield, 44.0% for RDMC and 7.6% for β-carotene content. Three genotypes designated as G1, G6 and G20 were identified as having above average RDMC of 31.82, 32.60 and 30.06%, high β-carotene content of 12.48, 14.27 and 13.99 mg 100 g-1 and, stable and high fresh root yields of 25.09, 26.92 and 25.46 t ha-1, respectively. These genotypes were selected for final evaluation and recommendations. Among the test environments, Arbaminch, Halaba and Areka better discriminated among genotypes for RDMC and fresh root yield while Areka, Dilla and Halaba were the environments better discriminated among genotypes for β-carotene content. Four environments, Arbaminch, Halaba, Areka and Dilla can be considered good environments for sweetpotato screening in southern Ethiopia. Kokate is not a good environment for sweetpotato testing in Southern Nation, Nationalities and People’s Regional State (SNNPRS). Generally, the current study demonstrated the possibility of breeding sweetpotato varieties with combined high RDMC, β-carotene content and a high fresh root yield, with wide adaptation for large scale production.

Screening of ethyl methane sulphonate mutagenized tef [Eragrostis tef (Zucc.) Trotter] population identifies Al-tolerant lines

ABSTRACT About 15,000 M2 seeds of ethyl-methane-sulphonate (EMS)-mutagenized population were screened along with Al-tolerant and sensitive checks and the M0 variety. Strongly acidic soil with an external application of a toxic Al-solution and exposure to moisture stress was used to maximize selection pressure. Twenty-one M2 plants with root lengths of greater than the mean of the tolerant check were selected and planted for seed production. Candidate M3 plants were investigated for Al-tolerance and for morpho-agronomic traits under greenhouse and field conditions, respectively. Highly significant differences were observed for Al-tolerance between the candidate mutant lines and the M0 (P < .001), and between mutant lines and the sensitive check (P < .001). Similarly, significant differences were observed between the mutant lines for 16 of the 20 quantitative traits measured. This study is the first to report successful induction of enhanced Al-tolerance in tef by using EMS mutagenized population.

Early generation genetic variation and heritability of yield and related traits among tef populations

The extent of genetic variation and heritability of a trait are among the major determinants of selection gains in plant breeding programs. The aim of this study was to determine the magnitude of genetic variation and inheritance of grain yield, and component traits of newly developed tef populations under moisture-stressed and non-stressed conditions for drought tolerance breeding. Seventeen crosses along with the parents were evaluated in the F2 generation under moisture-stressed and non-stressed conditions in northern Ethiopia during 2015 and 2016. There were marked genotypic and phenotypic variation among the crosses in the F2 generation for plant height, panicle length, peduncle length, number of productive tillers per plant, main shoot panicle seed weight, biomass yield, and grain yield under both test conditions, important for successful selection and genetic advancement. The families of DZ-Cr-387 x 207832 and DZ-Cr-387 x 222076 were high grain yielders with early maturity under both test conditions.

Evaluation of candidate orange-fleshed sweetpotato clones for nutritional traits

ABSTRACT Information on the nutrient contents of newly developed orange-fleshed sweetpotato (OFSP) varieties is required for recommendations to growers and the food industry. Therefore, the objectives of this study were to determine the nutritional value of newly developed OFSP clones and to establish the associations between β-carotene content and micro-nutrients for targeted large scale production to alleviate nutrient deficiencies. Seventeen OFSP and eight white/cream-fleshed sweetpotato clones were evaluated across six diverse environments (Halaba, Kokate, Areka, Arbaminch, Hawassa and Dilla) in southern Ethiopia in 2014 using a 5 × 5 simple lattice design. Nutritional traits data were collected on dry-weight basis and subjected to analysis of variance and correlation analyses. Environment, genotype, and genotype × environment interaction effects were highly significant (p < 0.01) for all parameters measured. A newly developed genotype, designated G8, had the highest contents of β-carotene (20.01 mg 100 g−1), protein (7.08%), iron (2.55 mg 100 g−1), zinc (1.42 mg 100 g−1), fructose (4.45%), glucose (5.34%) and sucrose (16.20%). Genotypes G15 and G19 also performed relatively well for the above nutritional traits. The three genotypes, G8, G15 and G19 had mean fresh root yield of 23.5,13.7 and 21.3 tha−1, respectively. These genotypes had root dry matter content of 26.99%, 25.23% and 33.09%, respectively. Β-carotene content had significant positive correlations with iron, zinc, fructose, glucose and sucrose content. This reflects the potential to breed for OFSP varieties enriched with the important micro-nutrients. Overall, the candidate OFSP clones, G8 (Resisto × PIPI-2), G15 (Resisto × Temesgen-23) and G19 (Resisto × Ogansagen-23) were good sources of nutritional traits such as vitamin A, iron, zinc, protein, sucrose, glucose and fructose. The selected genotypes can be recommended for large-scale production, food processing or further sweetpotato improvement to alleviate nutrient deficiencies in Ethiopia or similar environments in sub-Saharan Africa.