Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Genetic Diversity of Potato Cultivars for Nitrogen Use Efficiency Under Contrasting Nitrogen Regimes
Getahun, Baye Berihun ; Kassie, Molla Mekonen ; Visser, Richard G.F. ; Linden, Gerard van der - \ 2019
Potato Research (2019). - ISSN 0014-3065
Dutch potato cultivars - Ethiopian potato cultivars - Genetic diversity - Nitrogen use efficiency - Path coefficient analysis

Developing cultivars that use nitrogen more efficiently is a sustainable strategy for reducing nitrogen use in crop production. To assess the genetic diversity for nitrogen use efficiency (NUE) and related traits in potato, a total of 97 (88 for the Western-European market and 9 Ethiopian) cultivars were evaluated at two nitrogen levels (40 kg/ha and 120 kg/ha) for 24 quantitative traits in Debre-Tabor and Injibara (Ethiopia) in the 2013 main rainy season (June to September). Highly significant variation was found among genotypes for almost all measured traits. Plant height, NUE, tuber yield, and yield-related traits and model parameters for canopy development (maximum canopy covers area under the canopy curve) were significantly affected by N levels across locations. Dutch cultivars had more rapid initial canopy development and matured earlier than the Ethiopian cultivars at both N levels and locations. A hierarchical cluster analysis grouped the cultivars in 9 and 11 genetically distinct classes at low and high N, respectively. The genetic component accounted for a large portion of the phenotypic variation for plant height, tuber number per plant, average tuber weight, and NUE under both N regimes, as indicated by a high heritability. Strong phenotypic correlations were observed between NUE and tuber number per plant, days to maturity, tuber dry matter %, maximum canopy cover, and area under the canopy curve under both low and high N conditions. The result is indicative to set the best parental line selection criteria for crossing purpose and utilize the cultivars for further potato NUE breeding programmes.

Aquaponics, an inclusive business to save land and water and to provide nutritious diets to vulnerable groups
Slingerland, M.A. ; Kappers, B. ; Abebe, T. ; Getahun, A. - \ 2018
Genetic diversity of potato for nitrogen use efficiency under low input conditions in Ethiopia
Getahun, Baye Berihun - \ 2017
Wageningen University. Promotor(en): R.G.F. Visser, co-promotor(en): C.G. van der Linden. - Wageningen : Wageningen University - ISBN 9789463436595 - 219
solanum tuberosum - potatoes - genetic diversity - nitrogen - plant breeding - ethiopia - nutrient use efficiency - solanum tuberosum - aardappelen - genetische diversiteit - stikstof - plantenveredeling - ethiopië - nutriëntengebruiksefficiëntie

Potato is a prime food security crop for smallholder farmers in the highland part of North western Ethiopia. In this region, nutrient availability, especially nitrogen (N) is a major constraint for crop productivity. To obtain insight in the possibility of improving potato for growth under low N input conditions in Ethiopia, we evaluated CxE diploid back cross population, modern European and Ethiopian potato cultivars and local Ethiopian cultivars for their ability to grow and produce tubers under low and high N input conditions. The experiments were conducted under rainfed and irrigation conditions. Eighty-eight Dutch cultivars and 9 Ethiopian cultivars were evaluated in three locations in North-western Ethiopia, in 2013 and in 2015. The two years represent two different growth seasons: rain-fed (June-October 2013) and irrigated cultivation (February-June 2015). Similarly 100 CxE diploid back cross potato genotypes were evaluated in both rainfed and irrigation production seasons in 2014. The Growth of the plants was monitored throughout the growth cycle using canopy cover measurements, with modelled canopy characteristics, and other agronomic traits were measured as per the description. The effect of season and location was further investigated by a GGE Biplot genotype-by-environment interaction analysis, and genetic factors determining phenotypic traits and yield were identified through QTL mapping and association mapping. Ethiopian cultivars showed a remarkable, environment-dependent difference in utilisation of the canopy for tuber production. While total photosynthetic capacity was higher in Ethiopian cultivars than in Dutch cultivars in rainfed production season at Injibara, tuber production was higher in Dutch cultivars. This low radiation use efficiency was not observed in the other rain-fed location (Debre-Tabor). A Genotype by Environment analysis using GGE biplots demonstrates that, Irrespective of the N levels and locations, rainfed production season test environments were grouped as one mega environment and irrigation production season test environments as the other mega environment, indicating most of the variation for yield and nitrogen use efficiency (NUE) in the dataset may be caused by the effect of rain-fed vs irrigation season. Further trials are needed to confirm this result. The QTL mapping with the CxE diploid population and GWAS analysis with the Dutch cultivars discovered both season-environment and N-specific QTL as well as constitutive QTLs. Overall, N availability affects Dutch and Ethiopian cultivars differentially, with strong environmental interaction on canopy and yield traits. Rainfed and irrigated seasons in Ethiopia may require different breeding programs for improved yield under varying fertilizer levels. Both constitutive and environment-specific QTLs were identified that may be targets for breeding prorgams towards improved yield under Ethiopian cultivation conditions.

Prevalence of subclinical mastitis and associated risk factors at cow and herd level in dairy farms in North-West Ethiopia
Mekonnen, Sefinew Alemu ; Koop, G. ; Melkie, S.T. ; Getahun, C.D. ; Hogeveen, H. ; Lam, Theo J.G.M. - \ 2017
Preventive Veterinary Medicine 145 (2017). - ISSN 0167-5877 - p. 23 - 31.
Dairy - Ethiopia - Intramammary infection - Mastitis - Risk factor

Knowledge of mastitis pathogens and their predominance as well as understanding of risk factors are prerequisites to improve udder health in a herd, region or country. In Ethiopia, such information is scarce, despite the fact that mastitis is an important cattle disease in the country. A cross-sectional study that describes prevalence and causative agents of subclinical mastitis (SCM) as well as risk factors at cow and herd level was conducted on 167 dairy farms in North-West Ethiopia. On average, 33% of the quarters and 62% of the cows were California Mastitis Test (CMT) positive, but the within herd quarter level prevalence ranged between 0 and 100%. A total of 1543 milk samples, being 27 quarters that showed signs of CM, 606 CMT positive quarters and 910 CMT negative quarters were cultured, respectively 40%, 67% and 47% was positive on bacteriological culture. Coagulase negative staphylococci (CNS) (31%) followed by Staphylococcus aureus (9%) were the pathogens most frequently isolated. Based on face-to-face questionnaire data, 35 herd level and 13 cow level factors were evaluated for their association with SCM (based on CMT) and with a positive culture for any bacteria, CNS or S. aureus. Cows with a history of CM, of higher parity, >150 days in milk (DIM) and herds with owners that have >10th grade level of education had higher odds of SCM. The odds of being culture positive for any bacteria was higher in cows with ≥25% Holstein Friesian blood level (HBL), >150 DIM, housed on cemented floors, and milked by squeezing rather than stripping. Similarly, the odds of culturing CNS was higher in cows with 25–50% HBL, >150 DIM, and milked by squeezing. Staphylococcus aureus was more often found in cows with a history of CM and in larger herds. Checking the udder for mastitis, feeding cows according to their requirements and allowing calves to suckle the cows were negatively associated with SCM, with culturing any bacteria and with culturing CNS, respectively. Higher odds of SCM and of culturing CNS were found in herds owned by members of a dairy cooperative. In summary, we identified a high prevalence of SCM and intramammary infections with substantial variation between farms, and we found a number of risk factors explaining this variation. The risk factors for mastitis that were identified in this study can form the basis of an udder health control program specific for the dairy industry in North-West Ethiopia.

Prevalence of Escherichia coli O157 : H7 in beef cattle at slaughter and beef carcasses at retail shops in Ethiopia
Abdissa, Rosa ; Haile, Woynshet ; Fite, Akafete Teklu ; Beyi, Ashenafi Feyisa ; Agga, Getahun E. ; Edao, Bedaso Mammo ; Tadesse, Fanos ; Korsa, Mesula Geloye ; Beyene, Takele ; Beyene, Tariku Jibat ; Zutter, Lieven De; Cox, Eric ; Goddeeris, Bruno Maria - \ 2017
Bmc Infectious Diseases 17 (2017)1. - ISSN 1471-2334
Antimicrobial resistance - Beef cattle - Carcass - E. coli O157:H7 - Skins

Background: There is paucity of information regarding the epidemiology of Escherichia coli O157: H7 in developing countries. In this study, we investigated the occurrence of E. coli O157: H7 associated with beef cattle at processing plants and at retail shops in Ethiopia. Methods: Various samples were collected from beef cattle at slaughter/processing plants, carcass at retail shops and humans at health centers. E. coli O157: H7 was isolated, identified and characterized for antimicrobial resistance, using standard microbiological methods. Results: At the processing plants E. coli O157: H7 was detected in 1.89% of fecal, 0.81% of intestinal mucosal swab, 0.54% of skin swab and 0.54% of carcass internal swab samples. At retail shops it was detected in 0.8% of carcass and 0.8% of cutting board swab samples, while all samples from utensils, hands from workers, and fecal and stool samples were negative. All isolates were resistant to Amoxicillin, moderately resistant to Cefoxitine and Nitrofurantoins but susceptible to other antimicrobials tested. Conclusions:E. coli O157: H7 occurs at low prevalence in beef cattle, and the current sanitary dressing procedures in the processing plants and storage conditions in the retail shops are effective against E. coli O157: H7.

Sustaining reservoir use through sediment trapping in NW Ethiopia
Getahun, Mulatie Mekonnen - \ 2016
Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): Saskia Keesstra; Jantiene Baartman. - Wageningen : Wageningen University - ISBN 9789462579101 - 132
sediment - soil conservation - reservoirs - dams - models - ethiopia - sediment - bodembescherming - reservoirs - dammen - modellen - ethiopië

To increase crop production and improve food self-sufficiency, rain-fed agriculture need to be supplemented with irrigated agriculture. To this end, a large number of reservoirs had been constructed in Ethiopia. However, reservoirs are suffering from sedimentation. This study was conducted in Minizr catchment, NW Ethiopia to (1) quantify the sediment entering Koga reservoir, (2) to assess the functioning and effectiveness of the existing man-made sediment trapping (ST) measures and natural sediment sinks, and (3) to design a possible solution to tackle the problem. Results of three years (2013-2015) field data show that 38% of the transported sediment was trapped within the Minizr catchment. Although considerable efforts were made to trap the sediment within the catchment through implementing various ST measures, lack of an integrated ST approach causes the remaining 62% of the sediment load still entering Koga reservoir.

Low-land gully formation in the Amhara Region, Ethiopia
Rijkee, P. ; Keesstra, S.D. ; Getahun, M.M. - \ 2015
Geophysical Research Abstracts 17 (2015). - ISSN 1029-7006 - 1 p.
Land degradation and related processes such as gullying, flooding and sedimentation, are global phenomena. Their
economic consequences however are more severe in developing countries, which lack resources for prevention
and mitigation. In Ethiopia, therefore, gully erosion as a form of land degradation is a prime issue. Over the
past decade, gullies have formed in the foothills of the Minizr sub-catchment in the highlands of North-Western
Ethiopia. Local extension workers have reported increased gully growth rates in the past five years in the
downslope foothill areas. This study answers the following questions: has the gully growth rate indeed increased
over the past five years compared to historical rates? What is the mechanism behind gully formation in the study
area? In addition, this study looked at three possible root causes for increased erosion rates: changing land use,
an increase in the ground water level, and the implementation of soil and water conservation measures in the
watershed of the study area.
The merit of this study is twofold. First, it shows the applicability of a fast, accessible and accurate way to
digitally represent gullies through the use of video footage and photogrammetry. Secondly, it shows the dominant
processes in gully formation in the area, allowing for a justified selection of measures to halt further gully growth
and rehabilitate existing gullies.
Two medium and one large gully were selected for detailed analysis. All gullies were located in gently-sloped areas
(0-5%), with Vertisol-dominated soils. Gully shape and volume were derived using terrestrial photogrammetry
in AgiSoft PhotoScan Professional. Still frames exported from video footage served as input. Approximately 30
points per gully were sampled weekly for soil moisture content over the course of September, November, and
December 2014. In addition, the sites were checked for signs of subsurface flow at the end of the rainy season and
again 3 months into the dry season.
We expect that erosion rates have increased compared to historical rates. Gully formation in the study area is
primarily driven by subsurface flow, leading to dispersion and bank collapse. Extensive signs of subsurface flows
are visible in and around all research gullies. Land use has not changed significantly over the past decade, so
will not have played a role in the increased erosion rates. The influence of the change in groundwater level since
reservoir construction (2011) is pending analysis of current groundwater levels. With the implementation of stone
bunds and fanja yuu on all fields on every hillslope surrounding the study area, infiltration will have increased
significantly. Although this has decreased overland runoff, it will have increased ground water flows toward the
study area and therefore made the area more susceptible to erosion through subsurface flow mechanisms.
Soil conservation through sediment trapping: a review
Getahun, M.M. ; Keesstra, S.D. ; Stroosnijder, L. ; Baartman, J.E.M. ; Maroulis, J. - \ 2015
Land Degradation and Development 26 (2015)6. - ISSN 1085-3278 - p. 544 - 556.
streamside management zones - forest riparian buffers - agricultural watersheds - grassed waterway - filter strips - loess plateau - land-use - semiarid environment - conceptual-framework - northern ethiopia
Preventing the off-site effects of soil erosion is an essential part of good catchment management. Most efforts are in the form of on-site soil and water conservation measures. However, sediment trapping can be an alternative (additional) measure to prevent the negative off-site effects of soil erosion. Therefore, not all efforts should focus solely on on-site soil conservation, but also on the safe routing of sediment-laden flows and on creating sites and conditions where sediment can be trapped. Sediment trapping can be applied on-site and off-site and involves both vegetative and structural measures. This paper provides an extensive review of scientific journal articles, case studies and other reports that have assessed soil conservation efforts and the sediment trapping efficacy (STE) of vegetative and structural measures. The review is further illustrated through participatory field observation and stakeholders interview. Vegetation type and integration of two or more measures are important factors influencing STE. In this review, the STE of most measures was evaluated either individually or in such combinations. In real landscape situations, it is not only important to select the most efficient erosion control measures, but also to determine their optimum location in the catchment. Hence, there is a need for research that shows a more integrated determination of STE at catchment scale. If integrated measures are implemented at the most appropriate spatial locations within a catchment where they can disconnect landscape units from each other, they will decrease runoff velocity and sediment transport and, subsequently, reduce downstream flooding and sedimentation problems
Sediment storage dam: a structural gully erosion control and sediment trapping measure, northern Ethiopia.
Getahun, Mulatie - \ 2014
Zooplankton, fish communities and the role of planktivory in nine Ethiopian lakes
Vijverberg, J. ; Dejen, E. ; Getahun, A. ; Nagelkerke, L.A.J. - \ 2014
Hydrobiologia 722 (2014)1. - ISSN 0018-8158 - p. 45 - 60.
fresh-water zooplankton - top-down control - trophic relationships - subtropical lake - nutrient state - body-size - sri-lanka - shallow - reservoirs - food
Fish and zooplankton populations of nine Ethiopian freshwater lakes were quantitatively sampled along a North–South gradient. Differences in altitude and latitude resulted in a temperature gradient from North to South. We tested three hypotheses: (1) the degree of zooplanktivory decreases with water temperature, i.e. from North to South; (2) the degree of zooplanktivory increases with the abundance of large-bodied zooplankton; and (3) the pattern of zooplanktivory in eutrophic Ethiopian water bodies differs from other tropical and temperate water bodies. Proportions of zooplanktivory in the fish communities did not show a geographical trend, but mainly depended on fish species, zooplankton density and the availability of large-bodied cladocerans. The degree of zooplanktivory in eutrophic Ethiopian water bodies differs from other eutrophic water bodies, both temperate and tropical. In Ethiopia, the degree of zooplanktivory can be both low and high, in contrast with other tropical water bodies where zooplanktivory is generally low and with temperate eutrophic water bodies where it is generally high. As a result, predation pressure on zooplankton by fish varies dramatically amongst Ethiopian water bodies.
The Fish Fauna of Lake Victoria during a Centruy of Human Induced Perturbations
Witte, F. ; Kish-Machumu, M.A. ; Mkumbo, O.C. ; Wanink, J.H. ; Goudswaard, P.C. ; Rijssel, J.C. van; Oijen, M.J.P. van - \ 2013
In: Proceedings of the Fourth International Conference on African Fish and Fisheries / Snoeks, J., Getahun, A., Tervuren : Royal Museum for Central Africa (Zoological Documentation Online Series ) - ISBN 9789491615146 - p. 49 - 66.
The composition of fish communities of nine Ethiopian lakes along a north-south gradient: threats and possible solutions
Vijverberg, J. ; Dejen, E. ; Getahun, A. ; Nagelkerke, L.A.J. - \ 2012
Animal Biology 62 (2012)3. - ISSN 1570-7555 - p. 315 - 335.
rift-valley lakes - fresh-water ecosystems - species flock pisces - reproductive segregation - cyprinidae - tana - barbs - strategies - diversity - example
Fish populations of nine Ethiopian freshwater lakes were quantitatively sampled with a standardized protocol, using multi-mesh gill nets. In total, 27 species were identified, but only 14 species were common. Based on the common species, the fish communities showed large differences in their species composition, except for Lake Abaya and Lake Chamo which were similar. Most fish species were observed in only one or two lakes. Compared with the information reported in literature the present study generally underestimated the species richness. The empirical model of Amarasinghe and Welcomme (2002) for African lakes was used to estimate fish species richness, which was compared with species presence reported in literature. Biodiversity in the two northern highland lakes is low, but not lower than the model estimate. Lake Tana has a high biodiversity which is close to what is estimated by the model, but three Rift Valley lakes have low biodiversity, lower than estimated by the model. There are also strong indications for the Rift Valley lakes that species richness was higher in the past because the species richness reported in the older literature was generally much higher than those observed by us in the present study and those reported in the more recent literature. Threats like overfishing, high sediment load and degradation of habitats were identified. It is recommended that Ethiopia should develop guidelines for fishery legislation and implement it through an enforcement agency. Moreover, catchments management should be practiced to save the water bodies and their fish communities
Spawning migrations of the endemic Labeobarbus (Cyprinidae, Teleostei) species of Lake Tana, Ethiopia: status and threats
Anteneh, W. ; Getahun, A. ; Dejen, E. ; Sibbing, F.A. ; Nagelkerke, L.A.J. ; Graaf, M. de; Wudneh, T. ; Vijverberg, J. ; Palstra, A.P. - \ 2012
Journal of Fish Biology 81 (2012)2. - ISSN 0022-1112 - p. 750 - 765.
The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning during the rainy season (July to October), whereas eight other species are absent from these rivers and probably developed a new strategy of lacustrine spawning (macro-spatial segregation). One species (L. intermedius) probably spawns in the lake as well as in the rivers. Between the early 1990s and 2000s, the riverine spawners showed a decline of 75% in both biomass and number in both fishery independent surveys and in commercial catches. Reproductive migration makes fishes vulnerable to fisheries and other threats like habitat modifications. Lacustrine spawners are probably more resilient as they are not known to form spawning aggregations that can easily be exploited by fishermen. In addition, upstream rivers and catchments around Lake Tana are highly degraded by erosion and recently subjected to intensive habitat modification for irrigation and hydroelectric power generation. This article reviews results of field studies on the Labeobarbus spawning migration from Lake Tana to spawning rivers, giving emphasis on segregation and homing. It also summarizes existing and emerging threats which form potential causes for the decline of the migratory Labeobarbus species. Knowledge gaps on the reproductive biology are identified for further investigation
Lake Tana's (Ethiopia) Labeobarbus Species Flock (Cypriniformes: Cyprinidae): a Future of Biodiversity Conservation and Sustainable Exploitation?
Graaf, M. de; Nagelkerke, L.A.J. ; Dejen, E. ; Wudneh, T. ; Osse, J.W.M. ; Sibbing, F.A. - \ 2008
In: Proceedings of the 4th International Conference on African Fish and Fisheries, Addis Ababa, Ethiopia, 22-26 September 2008. - Tervuren, belgium : Royal Museum for Central Africa - p. 31 - 47.
Lake Tana, the source of the (Blue) Nile, is situated in the north-western highlands of Ethiopia and harbours an extraordinary diversity of cyprinid fishes. While cyprinid fishes are common and abundant throughout the world’s fresh water systems, the Labeobarbus species of Lake Tana form the only remaining intact species flock of large cyprinid fishes. Lake Tana and its Labeobarbus species flock provide(d?) an unique opportunity to study the selective forces driving speciation due, among others, to its relatively undamaged state. However, this undamaged state of the Labeobarbus species flock is seriously threatened by anthropogenic activities that have intensified over the past 30 years. Between the 1990s and early 2000s, Labeobarbus stocks decreased by 75%, most likely due to the increased fishing pressure after the introduction of a motorized commercial gillnet fishery. Many of the lake’s Labeobarbus species are highly vulnerable to exploitation during their spawning aggregations and upstream migrations. Erosion due to poor land use might have also contributed to habitat degradation of the upstream spawning sites. Between 2000 and 2010 the commercial fishing fleet has expanded from 5-10 to 50-100 boats, but the Labeobarbus CPUE of the commercial fishery appeared to have declined a further ~50% over the same period. A (final) blow to the survival of the species flock will probably be the planned and realized (Rib River) irrigation dams in the spawning rivers.
Looking ahead the 21st century in Ethiopia : a quest to achieve the millennium declaration goals in Ethiopia
Woldehanna, T. ; Getahun, T. - \ 2002
UNDP - 58 p.
The major histocompatibility class II alpha chain in salmonid fishes
Grimholt, U. ; Getahun, A. ; Hermsen, T. ; Stet, R.J.M. - \ 2000
Developmental and Comparative Immunology 24 (2000). - ISSN 0145-305X - p. 751 - 763.
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