Time filter

Source Type

Mulenga R.M.,Zambia Agriculture Research Institute | Legg J.P.,International Institute Of Tropical Agriculture | Ndunguru J.,Mikocheni Agriculture Research Institute | Miano D.W.,University of Nairobi | And 3 more authors.
Plant Disease | Year: 2016

A survey was conducted from April to May 2014 in 214 farmers’ fields located across six major cassava-producing provinces (Western, Northwestern, Northern, Luapula, Lusaka, and Eastern) of Zambia to determine the status of cassava mosaic disease (CMD) and the species diversity of associated cassava mosaic geminiviruses (CMG). Mean CMD incidence varied across all six provinces but was greatest in Lusaka Province (81%) and least in Northern Province (44%). Mean CMD severity varied slightly between provinces, ranging from 2.78 in Eastern Province to 3.00 in Northwestern Province. Polymerase chain reaction discrimination of 226 survey samples, coupled with complete DNA-A genome sequence analysis, revealed the presence of African cassava mosaic virus (ACMV), East African cassava mosaic virus (EACMV), and East African cassava mosaic Malawi virus (EACMMV) as single or mixed infections of different proportions. Single-virus infections were predominant, occurring in 62.8% (ACMV), 5.8% (EACMMV), and 2.2% (EACMV) of samples relative to mixedvirus infections, which occurred in 19.5% (ACMV + EACMMV), 0.4% (ACMV + EACMV), and 0.9% (ACMV + EACMV + EACMMV) of samples. Phylogenetic analysis revealed the segregation of virus isolates from Zambia into clades specific to ACMV, EACMV, and EACMMV, further confirming the presence of all three viruses in Zambia. The results point to a greater diversity of CMG across major cassava-growing provinces of Zambia and implicate contaminated cassava cuttings in disease spread. © 2016 The American Phytopathological Society.


Giller K.E.,Wageningen University | Tittonell P.,CIRAD - Agricultural Research for Development | Rufino M.C.,Wageningen University | van Wijk M.T.,Wageningen University | And 23 more authors.
Agricultural Systems | Year: 2011

African farming systems are highly heterogeneous: between agroecological and socioeconomic environments, in the wide variability in farmers' resource endowments and in farm management. This means that single solutions (or 'silver bullets') for improving farm productivity do not exist. Yet to date few approaches to understand constraints and explore options for change have tackled the bewildering complexity of African farming systems. In this paper we describe the Nutrient Use in Animal and Cropping systems - Efficiencies and Scales (NUANCES) framework. NUANCES offers a structured approach to unravel and understand the complexity of African farming to identify what we term 'best-fit' technologies - technologies targeted to specific types of farmers and to specific niches within their farms. The NUANCES framework is not 'just another computer model'! We combine the tools of systems analysis and experimentation, detailed field observations and surveys, incorporate expert knowledge (local knowledge and results of research), generate databases, and apply simulation models to analyse performance of farms, and the impacts of introducing new technologies. We have analysed and described complexity of farming systems, their external drivers and some of the mechanisms that result in (in)efficient use of scarce resources. Studying sites across sub-Saharan Africa has provided insights in the trajectories of change in farming systems in response to population growth, economic conditions and climate variability (cycles of drier and wetter years) and climate change. In regions where human population is dense and land scarce, farm typologies have proven useful to target technologies between farmers of different production objectives and resource endowment (notably in terms of land, labour and capacity for investment). In such regions we could categorise types of fields on the basis of their responsiveness to soil improving technologies along soil fertility gradients, relying on local indicators to differentiate those that may be managed through 'maintenance fertilization' from fields that are highly-responsive to fertilizers and fields that require rehabilitation before yields can improved. Where human population pressure on the land is less intense, farm and field types are harder to discern, without clear patterns. Nutrient cycling through livestock is in principle not efficient for increasing food production due to increased nutrient losses, but is attractive for farmers due to the multiple functions of livestock. We identified trade-offs between income generation, soil conservation and community agreements through optimising concurrent objectives at farm and village levels. These examples show that future analyses must focus at farm and farming system level and not at the level of individual fields to achieve appropriate targeting of technologies - both between locations and between farms at any given location. The approach for integrated assessment described here can be used ex ante to explore the potential of best-fit technologies and the ways they can be best combined at farm level. The dynamic and integrated nature of the framework allows the impact of changes in external drivers such as climate change or development policy to be analysed. Fundamental questions for integrated analysis relate to the site-specific knowledge and the simplification of processes required to integrate and move from one level to the next. © 2010 Elsevier Ltd.


Njoroge S.M.C.,International Crops Research Institute for the Semi Arid Tropics ICRISAT | Matumba L.,NRC Group | Kanenga K.,Zambia Agriculture Research Institute | Siambi M.,ICRISAT | And 3 more authors.
Journal of Food Protection | Year: 2016

A 3-year comprehensive analysis of aflatoxin contamination in peanut butter was conducted in Zambia, sub-Saharan Africa. The study analyzed 954 containers of 24 local and imported peanut butter brands collected from shops in Chipata, Mambwe, Petauke, Katete, and Nyimba districts and also in Lusaka from 2012 to 2014. For analysis, a sample included six containers of a single brand, from the same processing batch number and the same shop. Each container was quantitatively analyzed for aflatoxin B1 (AFB1) in six replicates by using competitive enzyme-linked immunosorbent assay; thus, aflatoxin contamination level of a given sample was derived from an average of 36 test values. Results showed that 73% of the brands tested in 2012 were contaminated with AFB1 levels >20 μg/kg and ranged up to 130 μg/kg. In 2013, 80% of the brands were contaminated with AFB1 levels >20 μg/kg and ranged up to 10,740 μg/kg. Compared with brand data from 2012 and 2013, fewer brands in 2014, i.e., 53%, had aflatoxin B1 levels >20 μg/kg and ranged up to 1,000 μg/kg. Of the eight brands tested repeatedly across the 3-year period, none consistently averaged ≤20 μg/kg. Our survey clearly demonstrates the regular occurrence of high levels of AF B1 in peanut butter in Zambia. Considering that some of the brands tested originated from neighboring countries such as Malawi, Zimbabwe, and South Africa, the current findings provide a sub-Saharan regional perspective regarding the safety of peanut butter.


PubMed | International Crops Research Institute for the Semi Arid Tropics ICRISAT, ICRISAT, Indian International Crops Research Institute for the Semi Arid Tropics, Zambia Agriculture Research Institute and NRC Group
Type: Journal Article | Journal: Journal of food protection | Year: 2016

A 3-year comprehensive analysis of aflatoxin contamination in peanut butter was conducted in Zambia, sub-Saharan Africa. The study analyzed 954 containers of 24 local and imported peanut butter brands collected from shops in Chipata, Mambwe, Petauke, Katete, and Nyimba districts and also in Lusaka from 2012 to 2014. For analysis, a sample included six containers of a single brand, from the same processing batch number and the same shop. Each container was quantitatively analyzed for aflatoxin B1 (AFB1) in six replicates by using competitive enzyme-linked immunosorbent assay; thus, aflatoxin contamination level of a given sample was derived from an average of 36 test values. Results showed that 73% of the brands tested in 2012 were contaminated with AFB1 levels >20 g/kg and ranged up to 130 g/kg. In 2013, 80% of the brands were contaminated with AFB1 levels >20 g/kg and ranged up to 10,740 g/kg. Compared with brand data from 2012 and 2013, fewer brands in 2014, i.e., 53%, had aflatoxin B1 levels >20 g/kg and ranged up to 1,000 g/kg. Of the eight brands tested repeatedly across the 3-year period, none consistently averaged 20 g/kg. Our survey clearly demonstrates the regular occurrence of high levels of AF B1 in peanut butter in Zambia. Considering that some of the brands tested originated from neighboring countries such as Malawi, Zimbabwe, and South Africa, the current findings provide a sub-Saharan regional perspective regarding the safety of peanut butter.


Chikoti P.C.,Zambia Agriculture Research Institute | Shanahan P.,University of KwaZulu - Natal | Melis R.,University of KwaZulu - Natal
Australian Journal of Crop Science | Year: 2016

Despite the importance of cassava as a staple crop in Luapula province and other regions of Zambia, there is a lack of information on the resistance to diseases and associated combining ability of the locally cultivated cassava cultivars. Therefore, this study was carried out in 2010/2011 to: identify progeny with resistance to cassava mosaic disease (CMD); evaluate the performance of F1 progeny for agronomic traits and determine general combining ability and specific combining ability for resistance to CMD. A total of 809 genotypes comprising of parents and progeny were developed through controlled crossing and evaluated using a-lattice design. The general combining ability (GCA) and SCA mean squares (MS) were highly significant (P<0.001) for CMD. The total sum of squares (SS) for CMD was mainly accounted for by specific combining ability (SCA) effects (67.9%). Bangweulu a local highly susceptible cultivar had the most negative, significant (P<0.001) GCA effect among the landraces. In summary, the results indicated that the local landraces (Bangweulu and Kampolombo) used as parents can be sources of CMD resistance.


Mukanga M.,University of KwaZulu - Natal | Mukanga M.,Zambia Agriculture Research Institute | Derera J.,University of KwaZulu - Natal | Tongoona P.,University of KwaZulu - Natal | Laing M.D.,University of KwaZulu - Natal
International Journal of Food Microbiology | Year: 2010

Maize ear rots reduce grain yield and quality with implication on food security and health. Some of the pathogenic fungi produce mycotoxins in maize grain posing a health risk to humans and livestock. Unfortunately, the levels of ear rot and mycotoxin infection in grain produced by subsistence farmers in sub-Saharan countries are not known. A survey was thus conducted to determine the prevalence of the ear rot problem and levels of mycotoxins in maize grain. A total of 114 farmsteads were randomly sampled from 11 districts in Lusaka and southern provinces in Zambia during 2006. Ten randomly picked cobs were examined per farmstead and the ear rot disease incidence and severity were estimated on site. This was followed by the standard seed health testing procedures for fungal isolation in the laboratory. Results indicated that the dominant ear rots were caused by Fusarium and Stenocarpella. Incidence of Fusarium verticillioides ranged from 2 to 21%, whereas that of Stenocarpella maydis reached 37% on ear rot diseased maize grain. In addition, 2-7% F. verticillioides, and 3-18% Aspergillus flavus, respectively, were recovered from seemingly healthy maize grain. The mean rank of fungal species, from highest to lowest, was F. verticillioides, S. maydis, A. flavus, Fusarium graminearum, Aspergillus niger, Penicillium spp., Botrydiplodia spp., and Cladosporium spp. The direct competitive ELISA-test indicated higher levels of fumonisins than aflatoxins in pre-harvest maize grain samples. The concentration of fumonisins from six districts, and aflatoxin from two districts, was 10-fold higher than 2. ppm and far higher than 2. ppb maximum daily intake recommended by the FAO/WHO. The study therefore suggested that subsistence farmers and consumers in this part of Zambia, and maybe also in similar environments in sub-Saharan Africa, might be exposed to dangerous levels of mycotoxins due to the high levels of ear rot infections in maize grain. © 2010 Elsevier B.V.


Bumbangi N.F.,University of Zambia | Muma J.B.,University of Zambia | Choongo K.,University of Zambia | Mukanga M.,Zambia Agriculture Research Institute | And 4 more authors.
Food Control | Year: 2016

Peanuts, one of the most susceptible crops to aflatoxin (AF) contamination, are widely produced and consumed in Zambia. This cross-sectional study was designed to determine the levels of AFs in raw peanuts sold in Lusaka district's markets as well as identify factors associated with increased AF presence. Raw peanut samples were collected from open markets and supermarkets and analyzed for aflatoxin contamination using high performance liquid chromatography (HPLC). A questionnaire was also administered to the peanut vendors to investigate factors contributing to increased levels of AFs in peanuts. Of the 92 samples, 51 (55.4%; 95% CI: 44.9-65.4) tested positive for presence of AFs. The overall median and geometric mean ± standard deviation (SD) concentration for AF were 0.23 ppb (range: 0.014-48.67 ppb) and 0.43 ± 9.77 ppb, respectively. The association between market types and presence of AFs was not statistically significant (Pearson Χ2 = 0.0587, p = 0.809). Of 51 samples that tested positive to AF, 6.5% and 12% were above the maximum permissible limits (MPLs) set by the Codex Alimentarius Commission and European Union standards, respectively. There was a significant difference in the levels of AF between Chalimbana and Kadononga (p<0.0001), and also Chalimbana and Makulu red (p<0.0001). Chalimbana was the most at risk of AF contamination, when compared to other peanut varieties. The high level of AFs in raw peanuts from both supermarkets and open markets samples constitutes a health hazard for the population of Lusaka district. Therefore, intervention strategies that reduce the levels of AF contamination in peanuts should be given priority. © 2016 Elsevier Ltd.


Chalwe A.,Zambia Agriculture Research Institute | Melis R.,University of KwaZulu - Natal | Shanahan P.,University of KwaZulu - Natal | Chiona M.,Zambia Agriculture Research Institute
Euphytica | Year: 2015

Cassava green mite (CGM) Mononychellus tanajoa (Bondar) (Acari: Tetranychidae) is a major arthropod pest causing significant loss in the yields of storage roots and planting materials of cassava in Zambia. Its control has been mainly based on the use of exotic predatory mites as biological control agents, which unfortunately, have not established well in Zambia due to the lack of suitable host genotypes and harsh weather conditions. The current study was aimed at breeding cassava for improvement of morphological traits that are associated with resistance to CGM, which can also enable cassava genotypes to provide shelter and ensure continuous survival of natural enemies of CGM, and to determine the inheritance of these traits by assessing combining ability and therefore the type of gene action involved in their expression. Using a 5 × 5 half diallel mating design, full-sib cassava genotypes were generated out of which 300 were selected and evaluated in the field. Data were collected for CGM density, CGM leaf damage and cassava mosaic disease severity, plant growth habit, leaf morphological traits, storage root yield and root dry mass. Both general and specific combining ability effects were significant (P < 0.01) for the reaction of the F1 progeny to CGM, and for the various plant morphological traits that were measured, suggesting that both additive and non-additive gene effects play a role in the expression of the traits. © 2015, Springer Science+Business Media Dordrecht.


Ng'Uni D.,Zambia Agriculture Research Institute | Shargie N.G.,Agricultural Research Council GCI | Andersson S.C.,Swedish University of Agricultural Sciences | Van Biljon A.,University of the Free State | Labuschagne M.T.,University of the Free State
Cereal Research Communications | Year: 2016

Sorghum is, globally, the fifth most important cereal after maize, rice, wheat and barley. The crop is tolerant to semi-arid and arid climatic conditions. Twenty-five sorghum varieties grown in South Africa were evaluated in the field at two locations with the objective of identifying high yielding, micronutrient dense genotypes. Two clusters were formed based on measured traits. Tx430 (G13), CIMMYT entry 49 (G12), E35-1 (G16), Framida (G19), IS1934 (G7) and IS14380 (G14) formed cluster A. The rest of the sorghum entries formed cluster B. Wide variation was exhibited for grain yield, ranging from 1.12 t ha-1 to 3.96 t ha-1 with a mean grain yield of 2.83 tha-1. Analysis of variance also revealed significant differences among the varieties for protein, total starch, amylose and mineral content. Two varieties, Tx430 and AR-3048 exhibited very high protein content. Fe content ranged from 43.7 mg kg-1 (Kuyuma) to 61.2 mg kg-1 (IS14380) with an average of 50.5 mg kg-1. Zn content ranged from 13.7 mg kg-1 (Macia) to 23.4 mg kg-1 (Tx430) with a mean of 17.4 mg kg-1. Grain yield was significantly positively correlated with plant height, panicle weight and thousand kernel weight. Significant positive correlations were observed between Fe content and Zn, Cu, Mn and P. This data indicated that simultaneous genetic improvement of sorghum varieties for Fe and other important minerals, and starch content in the same genetic background was possible, without a penalty to grain yield. © 2016 Akadémiai Kiadó, Budapest.


Ng'uni D.,Swedish University of Agricultural Sciences | Ng'uni D.,Zambia Agriculture Research Institute | Geleta M.,Swedish University of Agricultural Sciences | Bryngelsson T.,Swedish University of Agricultural Sciences
Hereditas | Year: 2011

Twenty seven accessions of sorghum conserved in the national gene bank of Zambia, representing two of the three agroecological regions of the country, were investigated using simple sequence repeats (SSR) markers in order to determine the extent and distribution of its genetic diversity. We used 10 microsatellite primer-pairs, which generated 2-9 alleles per locus and a total of 44 alleles across the 27 accessions. The observed heterozygosity (HoP) among the accessions ranged from 0 to 0.19 with an average of 0.04 whereas the average expected heterozygosity (HeP) among accessions was 0.07 in line with the fact that sorghum is predominately inbreeder. The analysis of molecular variance (AMOVA) revealed that 82% of the total genetic variation was attributable to the genetic variation among accessions (FST= 0.824; p < 0.001) whereas the genetic variation within accessions accounted for 18% of the total genetic variation. AMOVA on sorghum accessions grouped based on four ethnic groups (Soli, Chikunda, Lozi and Tonga) associated with collection sites revealed a highly significant variation among groups (23%; p < 0.001). Although cluster analysis grouped most accessions according to their sites of collection, some accessions that originated from the same site were placed under different clusters. In addition to the extent and pattern of genetic diversity, consideration should also be given to other factors such as ecogeographic and ethnic differences when sampling sorghum genetic resources for rational and efficient conservation and utilization in the breeding program. © 2011 The Authors.

Loading Zambia Agriculture Research Institute collaborators
Loading Zambia Agriculture Research Institute collaborators