Linley Chiwona-Karltun

The importance of being bitter—a qualitative study on cassava cultivar preference in Malawi

We conducted qualitative interviews in Nkhata‐Bay district in Malawi to elucidate why farmers preferentially grow cassava cultivars providing bitter roots. Cassava was mainly grown to produce flour for making the staple food, kondowole. Plants were identified as belonging to one of the 54 mentioned cultivars with local names. All the farmers stated that bitter taste of roots predicted toxicity and necessity for processing. Cultivars were grouped into “cool” or “bitter” based on whether the roots could be eaten fresh, or required processing before consumption as kondowole. Farmers strongly preferred cultivars grown for flour production to have bitter roots since this protected against theft, destruction by animals and deterred household members from unplanned harvest. Since processing is done by women bitterness empowers women to control the families staple crop. Bitter cultivars reportedly yielded more and roots produced an easier to mould kondowole. Bitterness and toxicity were not perceived as a problem.

Genetic diversity and variety composition of cassava on small-scale farms in Uganda: an interdisciplinary study using genetic markers and farmer interviews.

Cassava is a tropical crop and grown for its tuberous starchy roots. In Africa it is mainly cultivated by small-scale farmers who observe, select and name their cassava varieties based on morphology, food, social and economic interest. Here we have used an interdisciplinary approach involving farmer interviews, genetic markers and morphological descriptors to study the composition of cassava varieties on small-scale farms in 11 villages located in three districts in Uganda, the genetic structure within and between these varieties and their morphology. The composition of local, newly introduced and improved varieties differed widely between villages and districts. The Ugandan farmers in our study seemed to adopt improved varieties to a greater extent when there was a nearby market, prevalence of disease epidemics and good extension service. We found considerable genetic variation both within and between cassava varieties though the variation was larger between varieties. However, most local and improved varieties showed predominating genotypes at many loci. Accessions of commonly grown varieties meeting farmers’ preferences could therefore be selected and implemented in future breeding programmes involving development, dissemination and adoption. The like-named varieties in different villages were genetically similar, demonstrating farmers’ ability to differentiate and maintain the same variety over large areas. However, some varieties with different names in different villages showed both genetic and morphological similarity, suggesting that farmers may rename plants when they are introduced into their fields. The large differences found in variety and genetic composition between villages and districts in Uganda may be a result of the diverse needs and growing conditions characteristic for traditional farming system. This suggests that efforts to conserve and increase the genetic diversity in farmers’ fields will require policies tailored to each area.

Chemical safety of cassava products in regions adopting cassava production and processing – Experience from Southern Africa

The cassava belt area in Southern Africa is experiencing an unforeseen surge in cassava production, processing and consumption. Little documentation exists on the effects of this surge on processing procedures, the prevailing levels of cyanogenic glucosides of products consumed and the levels of products commercially available on the market. Risk assessments disclose that effects harmful to the developing central nervous system (CNS) may be observed at a lower exposure than previously anticipated. We interviewed farmers in Zambia and Malawi about their cultivars, processing procedures and perceptions concerning cassava and chemical food safety. Chips, mixed biscuits and flour, procured from households and markets in three regions of Zambia (Luapula-North, Western and Southern) as well as products from the Northern, Central and Southern regions of Malawi, were analyzed for total cyanogenic potential (CNp). Processed products from Luapula showed a low CNp, <10 mg HCN equiv./kg air dried weight, while samples from Mongu, Western Province, exhibited high levels of CNp, varying from 50 to 290 mg HCN equiv./kg. Even the lowest level is five times higher than the recommended safety level of 10mg/kg decided on for cassava flour. Our results call for concerted efforts in promoting gender oriented processing technologies.

Cassava commercialization in Southeastern Africa.

Purpose - Cassava production surged noticeably in Southeastern Africa beginning in the 1990s. The purpose of this paper is to examine the commercial responses and food security consequences of cassava production growth in the region. Design/methodology/approach - The paper incorporates a mix of quantitative analysis, based primarily on original analysis of national farm household survey data, together with key informant interviews with value chain participants in the three neighboring countries of Malawi, Mozambique and Zambia. Findings - In the cassava production zones, cassavas high productivity translates into per kilogram carbohydrate costs 60 per cent to 70 per cent of the cost of cereals such as maize and wheat, thereby opening up a range of profitable opportunities for commercialization of cassava-based foods, feeds and industrial products. Despite this potential, cassava commercialization in Southeastern Africa remains in its formative stages, with only 10 per cent to 30 per cent of production currently marketed. Unlike West Africa, where cassava commercialization has centered on marketing prepared cassava-based convenience foods, the emerging cassava markets in Southeastern Africa have centered on fresh cassava, low value-added cassava flour, and experiments in industrial processing of cassava-based starches, biofuels and feeds. Strategic investment in a set of key public goods (breeding, training in food sciences and food safety, and research on in-ground cassava storage) can help to shape this transition in ways that benefit both commercial interests and the food security of vulnerable households. Originality/value - The paper compares cassava commercialization across differing agro-climatic zones, policy environments and food staple zones.

Farmer Preference, Utilization, and Biochemical Composition of Improved Cassava (Manihot esculenta Crantz) Varieties in Southeastern Africa

Farmer Preference, Utilization, and Biochemical Composition of Improved Cassava ( Manihot esculenta Crantz) Varieties in Southeastern AfricaCassava (Manihot esculenta Crantz) varieties are ethnobotanically classified by farmers into two distinct classes—“sweet” or “bitter”—based on their taste, most often reflecting the inherent cyanogenic glucoside potential and intended end use. Varietal preference based on general utilization as well as more targeted end use for preferred local and improved varieties is poorly understood and not well documented. The objectives of this study were to investigate prevailing varietal preferences based on utilization and the biochemical composition of local and recently improved cassava varieties. Interviews were conducted with farmers to document the existing varieties, their origin and taste classification, and processing in relation to end use. Biochemical composition was determined for flour samples with particular emphasis on color and perceived dryness. Of the nine varieties identified, four were classified as local, while the rest were classified as improved varieties. Two varieties were classified as bitter, and the rest were classified as sweet based on end use. The classification dichotomy based on taste is an important factor in determining potential toxicity. Labile varieties that are easily affected by microenvironmental factors were classified as bitter. Reasons for preference and utilization focus as much on the leaves for use as vegetables as on the roots. The taste classification of the roots determines how and whether they are to be processed. The varieties “Mweulu” and “Tanganyika” were perceived by farmers as having excellent characteristics for making the staple dish “nshima,” reflected by their high carbohydrate contents. The variety “Bangweulu” was identified as having “bigger and starchier” roots in interviews, and the biochemical assay verified these observations. The flour sample analysis revealed crude protein content ranged from 4.86% to 7.09%. Cluster and principal component analyses showed four groupings, with the single Malawian variety exhibiting the greatest differences from the Zambian clones, while the improved varieties bred from a single mother line displayed the closest similarities. The high energy and carbohydrate values of the nine varieties provide a good basis for acceptance; however, factors such as shelf life, storage, and other postharvest qualities such as susceptibility to weevil attacks also play a determining role in the acceptance of improved cassava varieties.Makonda a Alimi, Kagwiritsidwe Ntchito, ndi kawuniwuni wa mitundu ya Chinangwa cha makono ( Manihot esculenta Crantz) ku M’mwera Chaku M’mawa Kwa AfricaMitundu ya Chinangwa (Manihot esculenta Crantz) ilipo iwiri – “Chokoma” ndi “Chowawa” malingana ndi makomedwe ake. Mitundu iwiriyi imawunikiranso kusiyana kwa kagwiritsidwe ntchito ka mitundu imeneyi. Kagwiritsidwe nchito ka mitundu ya chinangwa yochokera mu kafukufuku kapena mitundu ina ya makolo sizimvetsetsedwa bwino komanso sizinalembedwe bwino. Zolinga za kafukufuku uyu zinali kufufuza makonda a kagwiritsidwe ntchito ka mitundu ya chinangwa ndi kawawidwe mu chinangwa cha makolo komanso cha makono. Alimi osiyanasiyana anafunsidwa pofuna kulembera mitundu yosiyana siyana imene ilipo, kumene inachokera ndi gulu lomwe chili malingana ndi kakomendwe kake, komanso kakonzedwe kake ndi ntchito yake. Kukoma kapena kuwawa kwa chinangwa kunatsimikizidwa poyesa ufa wake, polingalira mtundu ndi maumidwe ake. Mwa mitundu isanu ndi inayi imene inazindikiridwa, inayi inali ya makolo, pamene yotsalayo inali ya makono. Mwa mitundu isanu ndi inayi, iwiri inali yowawa, ndipo yotsalayo inali yokoma polingalira ntchito yomwe chimagwiritsidwa. Kusiyanitsa magawo polingalira kakomedwe, ndi chinthu chofunika kwambiri pofuna kudziwa kuopsya kumene kungakhalepo pa kudya chinangwa. Mitundu “yowawirako” imene imakhudzidwa kwambiri ndi kusinthasintha kwa nyengo inapezeka kuti ndi yowawa. Zifukwa zokondera chinangwa zimalingaliridwanso pa kakomedwe ka masamba ngati ntapasha ngati m’mene ziliri ndi mizu ya chinangwacho. Kusiyanitsa mitundu ya chinangwa mu kakomedwe kake kumapangitsanso kudziwa momwe chingakonzedwere. Alimi anawona mitundu ya “Mweulu” ndi “Tanganyika” kukhala ndi makhalidwe abwino opangira chakudya chomwe amachidalira “nsima” chifukwa ndi chokhutitsa ndiponso chopatsa mphamvu. Pochezanso ndi alimi, mtundu wa “Bangweulu” unapezeka kukhala ndi mizu yaikulu ndi ufa wambiri” ndipo kafukufuku anatsimikiziranso izi. Ufa wachinangwa unapezeka kukhala ndi puloteni wa mlingo wa pakati pa 4.86 – 7.09%. Kawuniwuni wa magulu a chingwachi anapeza magulu akulu-akulu anayi. Mtundu umodzi waku Malawi unaonetsa kusiyana kwakukulu ndi mtundu wofana nawo waku Zambia, pamene mtundu wamakono wopangidwa kuchokera ku kholo limodzi unawonetsa zinthu zofananiranako kwambiri. Kukhutitsa ndi kupereka mphamvu kwa mitundu isanu ndi inayi ya chinangwayi ndilo gwero lalikulu limene alimi amachikondera; komabe, zinthu monga nthawi yomwe chingatenge chisanaonengeke, kasungidwe, ndi masamalidwe chikakololedwa monga kugwidwa ndi anankafumbwe zimapangitsanso momwe mbewu ya makono ya chinangwa ingakondedwere.

Application of Multivariate Techniques for Characterizing Composition of Starches and Sugars in Six High Yielding CMD Resistant Cassava ( Manihot esculenta Crantz ) Varieties

High yielding and cassava mosaic disease (CMD) resistant cassava varieties have been developed by the Crop Research Institute of Ghana with varying compositions and concentrations of starches and sugars. This study characterized four of these improved cassava varieties (Ampong, Broni bankye, Sika and Otuhia) together with two traditional varieties (Amakuma and Bankye fitaa) for their composition of starches and sugars using principal component and cluster analyses. The concentration of total sugars, reducing and non-reducing sugars, sucrose, starches, amylose and amylopectin were determined using standard analytical methods. Results obtained were total sugar (4.04-18.47%), non-reducing sugar (2.08-16.21%), sucrose (1.98-15.40%), starch (15.39-31.07%) and amylose (30.57-40.33%) and these were significantly different (p < 0.05) amongst the studied cassava varieties. The improved varieties (Ampong, Broni bankye, Sika and Otuhia) had high total sugar levels ranging from 7.19 to 18.47 %. With the exception of Broni bankye (improved variety) all the improved and traditional varieties were high starch and amylose containing varieties. These differences in the biochemical composition of the traditional and improved cassava varieties could be used in their selection for specific food and industrial processing applications.

Experiences and perceptions of South---South and North---South scientific collaboration of mathematicians, physicists and chemists from five southern African universities

Faced with limited resources, scientists from around the world enter into collaborations to join their resources to conduct research. Like everywhere else, international co-publishing in southern African countries is increasingly on the rise. The aim of this study was to document and analyse the level of scientific productivity, collaboration patterns, scientists’ experiences and attitudes towards South–South and South–North collaboration. We performed 105 interviews with scientists based at five southern African Universities, namely; University of Malawi—Chancellor College, National University of Science and Technology, the University of Botswana, the University of Zambia, and the University of Zimbabwe. We also traced 192 scientists from the various departments at these universities that had jointly published 623 scientific papers in the field of basic sciences in the period 1995–2014 in Web of Science journals. Our results show that in the majority of the cases funding from the North contributed substantially to increased scientific productivity, and international co-authorship. The results also show that collaboration with southern scientists is equally valued as that with northern scientists, but for different reasons. We conclude that supporting international and national collaboration which includes increased scientific mobility, strong scientific groups and networks, are key factors for capacity building of research in southern African Universities.

Viscoelastic Properties and Physico-Functional Characterization of Six High Yielding Cassava Mosaic Disease-Resistant Cassava (Manihot Esculenta Crantz) Genotypes

Investigations were conducted to characterize six high yielding cassava mosaic disease (CMD) resistant cassava varieties (Ampong, Broni bankye, Sika, Otuhia, Amakuma and Bankye fitaa) that have been developed by the Crop Research Institute of Ghana in collaboration with the International Institute for Tropical Agriculture for their differences and similarities in viscoelastic properties and physico-functional characteristics. The viscoelastic properties (pasting temperature, peak viscosity, final viscosity, breakdown viscosity and setback viscosity), and physico-functional characteristics (swelling power, solubility and water binding capacity) were determined using standard analytical methods. The results showed wide variations in viscoelastic properties with values ranging from 270.67-380.67 BU for peak viscosity, 37.17-260 BU for final viscosity, 199.83-282.33 BU for breakdown viscosity, 21.83-98.66 BU for setback viscosity and 2.48-10.51 min time to pasting temperature. Similarly, variations in swelling power, solubility and water binding capacity were noted with values ranging between 14.34-17.04%, 73.04-79.98% and 234.53- 276.63% respectively for all the different cassava genotypes. Statistical analysis showed significant differences (P < 0.05) amongst the studied cassava genotypes with Sika (improved variety) having exceptionally high viscoelastic characteristics. The differences noted in the viscoelastic properties and physico-functional characteristics of the six CMD resistant cassava genotypes could be used in their selection for specific food and industrial processing applications.

Coping with the Double Crisis: Lake Chilwa Recession and the Great Depression on Chisi Island in Colonial Malawi, 1930–1935

Environmental history is to a large extent framed by the neoclassical principle of generalized scarcity that recognizes that nature changes, both independently and in response to human actions, and thus changes the context in which human history unfolds (McNeill 2003). At the same time, political ecology puts more emphasis on power and inequalities as direct drivers of scarcity (Blaikie and Brookfield 1987; Peet and Watts 2004; Robbins 2012). However, both approaches can enhance our understanding of the influences acting upon coping strategies during resource scarcity. During the 1930s, people in the Lake Chilwa Basin in Malawi had to cope with both the drying up of Lake Chilwa and the global economic depression. We chose to describe this confluence on Chisi Island as the ‘double crisis,’ and it may at first glance seem obvious, but on examination becomes quite complex. In the case of the Lake Chilwa, the colonial administration introduced cotton production on the dry lake bed to boost the economy of Nyasaland in the face of the economic depression. However, the people of Chisi Island successfully resisted cotton farming. The ‘double crisis’ illustrates how power-relations shape scarcity and vice versa. Environmental scarcity is understood as the decrease in quantity and quality of renewable resources caused by three main processes: i) environmental changes; ii) population increase; and iii) unequal social distribution of resources, also termed ‘structural scarcity’ (de Sherbinin and Dompka 1998). Scarcity therefore becomes a naturally recurring limitation on the availability of resources or goods within an ecological system affecting the organization and functioning of societies. Economic historians, for example, argue that land-labor ratios have had a lasting impact on inequality and power relations because the use of slavery and/or bonded labor has historically been more common in geographical areas of land abundance and labor scarcity (Austin 2008; Green 2014). Environmental historians address degradation associated with non-renewable resources, environmental change associated with human transformation of renewable resources and environmental rehabilitation, conservation, and preservation (Hughes 2001; Worsted 1993). Similarly, a key feature of African environmental historiography is its emphasis on the conservationist paradigm of managing scarcity of natural resources (Kwashirai 2012; Mulwafu 2010). Political ecologists have criticized the environmental scarcity framework for neglecting inequality and power relations. Political ecologists emphasize that power and politics determine access to and distribution of specific resources and thus have the potential to create scarcity for the society at large * Joseph Nagoli Joseph.Nagoli@slu.se

Doing things their way? Food, farming and health in two Ugandan cities.

Abstract This paper presents new data on urban households’ agriculture, food environments and non-communicable disease (obesity, diabetes, hypertension) in two intermediate-sized Ugandan cities (Mbale and Mbarara). Nutrition transition theory suggests that fast-foods, eating out and supermarket shopping, together with sedentary urban lifestyles and less agricultural activity, are drivers of growing non-communicable disease burden. We explore these claims using statistics from a 2015 socio-economic and anthropometric survey of 1995 households. Results indicate that these cities are already experiencing non-communicable diseases, despite a lack of advanced food system and nutritional transitions. Surveyed households generally had low or medium dietary diversity, and a diet pattern and an agricultural practice primarily geared towards staple foods. Food transfers (mainly staples) from rural relatives were common, particularly for agricultural households. These farming households also had better income status than non-farming households. Experience of food insecurity was relatively common. Nevertheless, high prevalence and strongly gendered patterns of obesity were identified. In contrast to some theorising of the farming practice of urban-based households, there was little evidence that such agriculture was fuelled by poverty, vulnerability or migrant status. Findings also imply that there are other drivers of epidemiologic change in these cities than those suggested by nutrition transition theory.