Mikocheni Agricultural Research Institute MARI

Dar es Salaam, Tanzania

Mikocheni Agricultural Research Institute MARI

Dar es Salaam, Tanzania
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Tippe D.E.,Wageningen University | Rodenburg J.,Africa Rice Center | Schut M.,International Institute Of Tropical Agriculture | Schut M.,Wageningen University | And 3 more authors.
Crop Protection | Year: 2017

Rain-fed rice production in sub-Saharan Africa is often hampered by parasitic weeds. This study assessed farmers’ awareness, use, preference and adoption criteria of parasitic weed management practices in rain-fed rice production environments in Tanzania. Surveys and workshops were organized in three affected rice growing areas in Morogoro-rural, Songea and Kyela district, supplemented with on-farm experiments in Kyela. In all districts, farmers were aware of the locally occurring parasitic weed species, Rhamphicarpa fistulosa (lowland) and Striga asiatica (upland), and they considered these weeds more problematic than non-parasitic weeds. Though they mostly practise hand weeding, farmers were aware of a wide range of control options. Local access, affordability, ease of implementation and control efficacy were considered important criteria for adoption, whereas trade-offs, like lack of preferred grain quality traits in resistant varieties, were mentioned as an important break on adoption. Based on informal discussions with farmers, altered sowing times, resistant rice varieties and soil amendments were marked as feasible control options and tested in a farmer-participatory manner in four years of experimentation in upland and lowland fields. In both types of fields, the contribution of soil amendment to parasitic weed suppression was not evident, but rice husk was marked as a suitable and cheap alternative to inorganic fertilizers. Control of R. fistulosa in lowlands was perceived to be best realized by early crop establishment, escaping major parasite damage due to the relatively slow early development of this weed species. The local variety Supa India, appreciated for its grain qualities and marketability, remained the preferred variety. For the control of S. asiatica, late planting was preferred, requiring a short-duration variety to minimize risk of drought stress during grain filling. The short-duration NERICA-10 was most preferred, as it combined a favourable short cycle length with resistance to S. asiatica and good grain appearance. Farmer participation in technology testing showed to be crucial in defining locally adapted and acceptable parasitic weed control strategies. Yet, it is argued that without lifting important constraints related to credit and input supply, it will be impossible to sustainably solve the parasitic weed problem in rain-fed rice. © 2017 Elsevier Ltd

Du Plessis H.,North West University South Africa | Seguni Z.S.,Mikocheni Agricultural Research Institute MARI
Pest Management Science | Year: 2013

BACKGROUND: Cashew, Anacardium occidentale, is an economically important cash crop for more than 300000 rural households in Tanzania. Its production is, however, severely constrained by infestation by sap-sucking insects such as Helopeltis anacardii, H. schoutedeni and Pseudotheraptus wayi. The African weaver ant, Oecophylla longinoda, is an effective biocontrol agent of hemipteran pests in coconuts in Tanzania, but its efficacy in the control of Helopeltis spp. and P. wayi in Tanzanian cashew has not been investigated so far. The aim of this study was therefore to evaluate the efficacy of O. longinoda in the management of these insect pests in the cashew crop at different sites of the Coast region of Tanzania. RESULTS: Colonisation levels of O. longinoda, expressed as weaver ant trails, varied from 57.1 to 60.6% and from 58.3 to 67.5% in 2010 and 2011 respectively. The mean number of leaf nests per tree varied from five to eight nests in 2010 and from five to nine nests in 2011. There was a negative correlation between numbers of nests and pest damage. Oecophylla longinoda-colonised cashew trees had the lowest shoot damage by Helopeltis spp. of 4.8 and 7.5% in 2010 and 2011, respectively, as opposed to uncolonised cashew trees with 36 and 30% in 2010 and 2011 respectively. Similarly, nut damage by P. wayi was lowest in O. longinoda-colonised trees, with only 2.4 and 6.2% in 2010 and 2011 as opposed to uncolonised trees with 26 and 21%. CONCLUSION: Oecophylla longinoda is an effective biocontrol agent of the sap-sucking pests of cashew in the Coast region of Tanzania and should be considered as an important component of IPM. © 2012 Society of Chemical Industry.

Du Plessis H.,North West University South Africa | Seguni Z.S.,Mikocheni Agricultural Research Institute MARI
International Journal of Tropical Insect Science | Year: 2015

The efficacy of fish- and hydramethylnon-based baits for conservation of the African weaver ant (AWA) Oecophylla longinoda Latreille was evaluated at orchards in Bagamoyo and Mkuranga districts, Coast region of Tanzania, during the cashew off-seasons in 2011 and 2012. The baits were applied at monthly intervals; the dynamics of AWA were monitored by counting the number of leaf nests/tree and the colonization trails on main branches. The numbers of leaf nests recorded before baiting ranged between 3.5 and 5.3 and were not significantly different at both sites and in both seasons; after baiting, they ranged between 3.2 and 11.6 at Bagamoyo and between 3.0 and 10.2 at Mkuranga. The colonization of AWA trails recorded before baiting was also not significantly different at both sites and in both seasons and ranged between 37.9 and 50.0%; after baiting, this ranged between 35.9 and 75.1% at Bagamoyo and between 34.6 and 79.2% at Mkuranga. The provision of fish- and hydramethylnon-based baits can effectively contribute to the conservation of AWA during the cashew off-seasons. The fish-based bait is cheaper and more easily affordable by local farmers and can, therefore, be used as an alternative diet for AWA at this time. Copyright © ICIPE 2015.

Schut M.,Wageningen University | Schut M.,International Institute Of Tropical Agriculture | Klerkx L.,Wageningen University | Rodenburg J.,Africa Rice Center | And 6 more authors.
Agricultural Systems | Year: 2015

This paper introduces Rapid Appraisal of Agricultural Innovation Systems (RAAIS). RAAIS is a diagnostic tool that can guide the analysis of complex agricultural problems and innovation capacity of the agricultural system in which the complex agricultural problem is embedded. RAAIS focuses on the integrated analysis of different dimensions of problems (e.g. biophysical, technological, socio-cultural, economic, institutional and political), interactions across different levels (e.g. national, regional, local), and the constraints and interests of different stakeholder groups (farmers, government, researchers, etc.). Innovation capacity in the agricultural system is studied by analysing (1) constraints within the institutional, sectoral and technological subsystems of the agricultural system, and (2) the existence and performance of the agricultural innovation support system. RAAIS combines multiple qualitative and quantitative methods, and insider (stakeholders) and outsider (researchers) analyses which allow for critical triangulation and validation of the gathered data. Such an analysis can provide specific entry points for innovations to address the complex agricultural problem under study, and generic entry points for innovation related to strengthening the innovation capacity of agricultural system and the functioning of the agricultural innovation support system. The application of RAAIS to analyse parasitic weed problems in the rice sector, conducted in Tanzania and Benin, demonstrates the potential of the diagnostic tool and provides recommendations for its further development and use. © 2014 The Authors.

Schut M.,Wageningen University | Schut M.,International Institute Of Tropical Agriculture | Rodenburg J.,Africa Rice Center | Klerkx L.,Wageningen University | And 3 more authors.
Agricultural Systems | Year: 2015

Parasitic weeds such as Striga spp and Rhamphicarpa fistulosa in smallholder rice production systems form an increasing problem for food and income security in sub-Saharan Africa. In this paper we implement the Rapid Appraisal of Agricultural Innovation Systems (RAAIS) as a diagnostic tool to identify specific and generic entry points for innovations to address parasitic weeds in rain-fed rice production in Tanzania. Data were gathered across three study sites in Tanzania where parasitic weeds are eminent (Kyela, Songea Rural and Morogoro Rural districts). The results demonstrate that in Tanzania, weeds in general and parasitic weeds in particular receive little attention in agricultural research, training and education curricula. Crop protection policies mainly focus on the control of (insect) pest and diseases and there is relatively little attention for weed prevention, which is essential for addressing parasitic weed problems effectively. Specific entry points for innovation include increasing awareness of parasitic weed problems among farmers, extension and crop protection officers and policymakers. In regions where awareness is relatively high, participatory research approaches can provide a basis for developing locally adapted parasitic weed management strategies. Generic entry points for innovation include enhanced collaboration and interaction between stakeholders across different levels, for example in multi-stakeholder platforms. This can provide the basis for developing and implementing coherent policy and development strategies to address structural constraints in the agricultural system, including the promotion of clean local seed systems, investments in physical and knowledge infrastructure development, adequate backstopping of agricultural extension officers, agribusiness training for farmers, quality control of agricultural inputs, timely access to agricultural inputs, and improved access to markets for farmers. Together the specific and generic entry points can strengthen the innovation capacity of Tanzania's agricultural system to address parasitic weed problems, as well as other complex agricultural problems. © 2014 Elsevier Ltd.

PubMed | International Institute Of Tropical Agriculture, Mikocheni Agricultural Research Institute MARI, National Root Crops Research Institute NRCRI, Cornell University and 7 more.
Type: Journal Article | Journal: Nature biotechnology | Year: 2016

Cassava (Manihot esculenta) provides calories and nutrition for more than half a billion people. It was domesticated by native Amazonian peoples through cultivation of the wild progenitor M. esculenta ssp. flabellifolia and is now grown in tropical regions worldwide. Here we provide a high-quality genome assembly for cassava with improved contiguity, linkage, and completeness; almost 97% of genes are anchored to chromosomes. We find that paleotetraploidy in cassava is shared with the related rubber tree Hevea, providing a resource for comparative studies. We also sequence a global collection of 58 Manihot accessions, including cultivated and wild cassava accessions and related species such as Cear or India rubber (M. glaziovii), and genotype 268 African cassava varieties. We find widespread interspecific admixture, and detect the genetic signature of past cassava breeding programs. As a clonally propagated crop, cassava is especially vulnerable to pathogens and abiotic stresses. This genomic resource will inform future genome-enabled breeding efforts to improve this staple crop.

PubMed | University of Sheffield, Mikocheni Agricultural Research Institute MARI and Africa Rice Center
Type: | Journal: Field crops research | Year: 2015

The parasitic weeds

Rodenburg J.,Africa Rice Center | Cissoko M.,Africa Rice Center | Dieng I.,Africa Rice Center | Kayeke J.,Mikocheni Agricultural Research Institute MARI | Bastiaans L.,Wageningen University
Field Crops Research | Year: 2016

The facultative parasitic weed Rhamphicarpa fistulosa, is a widespread problem in rain-fed rice production systems in Africa. Little is known about rice varietal differences in infection level and yields in fields infested by this root hemi-parasite. During three cropping seasons (2012-2014), an experiment was conducted to address these knowledge gaps and to identify suitable variety selection criteria for R. fistulosa resistance and tolerance. Sixty-four adapted lowland rice varieties, including all interspecific lowland varieties of NERICAs, their most common parents - IR64 and TOG5681 - and two locally popular varieties - Mwangulu and Supa India - were grown in an R. fistulosa-infested field in southern Tanzania. As expected from a facultative parasite, host plant varieties had no effect on R. fistulosa numbers. Consistent varietal differences in R. fistulosa biomass were however observed, with no Year×Variety effects, and this parameter can therefore be used to select for resistance. Parasite-free observation plots were established in the last year. Due to the facultative nature of the parasite, creating such R. fistulosa-free plots was simply obtained by regular early weeding. The presence of parasite-free control plots enabled assessment of worthwhile additional information such as parasite-free yield, parasite-inflicted yield losses (RYLR) and varietal differences in tolerance. Under R. fistulosa-infested conditions (3-season averages, no Year×Variety interaction effect), rice grain yields ranged from 1.2tha-1 for the worst performing variety (TOG5681) to 2.4tha-1 for the best performing varieties (NERICA-L-39, -20). Under R. fistulosa-free conditions (2014 only) rice grain yields ranged from 2.4 (NERICA-L-22) to 5.4tha-1 (NERICA-L-17). Tolerant varieties were characterized by a low RYL R and a high parasite biomass (e.g. Supa India, NERICA-L-20). The selection measures identified are effective, easy and practical under field conditions. They facilitated identification of thirteen varieties with high resistance, sixteen varieties with low RYL R and two varieties with high tolerance. These varieties would be invaluable for future rice breeding programs. For farmers in R. fistulosa-endemic areas the most promising varieties are probably NERICA-L-40 and -31, as they combine good yields under infested conditions with low levels of parasite infection. © 2016 Elsevier B.V.

Bull S.E.,University of Bath | Ndunguru J.,Mikocheni Agricultural Research Institute MARI | Gruissem W.,ETH Zurich | Beeching J.R.,University of Bath | Vanderschuren H.,ETH Zurich
Plant Cell Reports | Year: 2011

Knowledge and technology transfer to African institutes is an important objective to help achieve the United Nations Millennium Development Goals. Plant biotechnology in particular enables innovative advances in agriculture and industry, offering new prospects to promote the integration and dissemination of improved crops and their derivatives from developing countries into local markets and the global economy. There is also the need to broaden our knowledge and understanding of cassava as a staple food crop. Cassava (Manihot esculenta Crantz) is a vital source of calories for approximately 500 million people living in developing countries. Unfortunately, it is subject to numerous biotic and abiotic stresses that impact on production, consumption, marketability and also local and country economics. To date, improvements to cassava have been led via conventional plant breeding programmes, but with advances in molecular-assisted breeding and plant biotechnology new tools are being developed to hasten the generation of improved farmer-preferred cultivars. In this review, we report on the current constraints to cassava production and knowledge acquisition in Africa, including a case study discussing the opportunities and challenges of a technology transfer programme established between the Mikocheni Agricultural Research Institute in Tanzania and Europe-based researchers. The establishment of cassava biotechnology platform(s) should promote research capabilities in African institutions and allow scientists autonomy to adapt cassava to suit local agro-ecosystems, ultimately serving to develop a sustainable biotechnology infrastructure in African countries. © 2011 Springer-Verlag.

Lyimo L.D.,The University of Dodoma | Tairo F.M.,Mikocheni Agricultural Research Institute MARI | Rweyemamu C.L.,Sokoine University of Agriculture
International Journal of Integrative Biology | Year: 2012

Genetic diversity of thirty nine (39) Tanzanian landraces of cassava (Manihot esculenta Crants) was studied using below and above-ground morphological descriptors followed by genomic DNA characterization using 13 SSR primers. Analysis of variance showed that all the characters evaluated were significantly different (P<0.01) between the genotypes. The dendrogram obtained using both phenotypic and molecular markers separated the genotypes into three major clusters with a Euclidean distance ranging from 0.53 to 0.91 and 0.33 to 0.88 respectively. The 85 SSR loci revealed a total of 89 alleles, out of which 75 alleles were found to be polymorphic with 84% level of polymorphism. The results, summarized on both dendrograms, showed wide genetic diversity among landraces providing scope for their improvement through hybridization and selection. In both methods no cassava duplicate was identified, though the most morphologically closely related cassava landraces were Sindani and Ndingiwaka with similarity coefficient of 0.91. Similarly the most genetically closely related cassava landraces were Mama and Mahuhu that had Jacquard's coefficient of 0.88. High polymorphic information content (PIC) was recorded in all primers except SSRY171 which had 0.22. The plot of the first three principal components scored generated 3-dimension scatter graph that showed the relationship between the 39 cassava landraces. © OmicsVista Group, All rights reserved.

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