Attempts to identify Cassava Brown Streak Virus in western Democratic Republic of Congo

Open Access ArticleRoot necrosis similar to those of the cassava brown streak disease (CBSD) were observed on cassava in western provinces of the Democratic Republic of Congo (DR.Congo) in the early 2000’s. However molecular laboratory diagnosis were not able to detect any causative agent responsible for the attacks, hence, the disease related to these symptoms was named CBSD-like disease. In order to assess the distribution and the incidence of the CBSD-like disease, surveys were carried out in four western provinces, comprising, Kwango and Kwilu, Sud Ubangi, Kinshasa and Kongo Central. CBSD-like disease was observed in all surveyed provinces on the basis of root symptoms because foliar symptoms were different to those of the documented cases of CBSD in other parts of east Africa. CBSD-like disease incidence was high in Kongo Central and Sud Ubangi, exceeding an average of 50 %, but low in Kwango and Kwilu (32.8%) and in Kinshasa (19.1%). During the surveys, cassava leaf samples were collected for lab identification of the causal agent. PCR diagnosis was done on these samples using primers specific for the two known CBSVs. All samples tested negative with no amplification of DNA fragments of the correct size. Thus, further analysis on the causative organism is needed using Next Generation Sequencing (NGS) approaches. NGS approaches will help also to identify the causative organism in other Central Africa countries (Angola, Congo-Brazzaville and Gabon) where such cassava root necrosis have been reported or are suspected

Fertilizer Use Issues for Smallholder Agriculture in Tropical Africa

Fertilizer is an essential input for wide-scale sustainable intensification of crop productivity in tropical Africa, but its use by smallholders is often financially constrained. Four fertilizer use issues are addressed. Smallholders need high net returns from their investments, with acceptable risk, which can be achieved with good crop-nutrient-rate choices made in consideration of the farmer’s financial and agronomic context. Soil acidification, which is affected by crop N supply, is best managed with the use of slightly more acidifying but less costly common N fertilizer, e.g., urea, coupled with lime use compared with the use of more costly but less acidifying N fertilizer such as calcium ammonium nitrate. This chapter addresses the feasibility of tailored fertilizer blends for maximizing farmer profit with respect to the nutrient supply cost, the need for flexibility in nutrient application according to the farmer’s context, and the weak justification for tailoring blends based on soil test results. The use of a well-formulated blends is justified in some cases, e.g., for some crops in Rwanda, but the supply of blends does not justify restricting the supply of common fertilizers. Farmers need to be aware that unregulated nontraditional products very often fail to provide the claimed benefits. Fertilizer use, sometimes with timely lime application, can be highly profitable with modest risk with good crop-nutrient-rate choices, adequate free-market fertilizer supply, and avoiding products with unsubstantiated claims

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Lemon technologies and adoption: measurement, theory and evidence from agricultural markets in Uganda

To reduce poverty and food insecurity in Africa requires raising productivity in agriculture. Systematic use of fertilizer and hybrid seed is a pathway to increased productivity, but adoption of these technologies remains low. We investigate whether the quality of agricultural inputs can help explain low take-up. Testing modern products purchased in local markets, we find that 30% of nutrient is missing in fertilizer, and hybrid maize seed is estimated to contain less than 50% authentic seeds. We document that such low quality results in low average returns. If authentic technologies replaced these low-quality products, however, average returns are high. To rationalize the findings, we calibrate a learning model using data from our agricultural trials. Because agricultural yields are noisy, farmers’ ability to learn about quality is limited and this can help explain the low quality equilibrium we observe, but also why the market has not fully collapsed

Final report : strengthening the capacity for research and development to enhance natural resources management and improve rural livelihoods in sub-Saharan Africa

The project worked to strengthen partnerships and build capacity of National Agricultural Research and Extension Systems (NARES) researchers, NGOs, CBOs and farmers groups to carry out research for development, using participatory research approaches and natural resource management, to improve livelihoods of the poor. The report highlights some of the project accomplishments and gives recommendations that form the basis for future work. Barriers and bottlenecks to effective agro-enterprise development need to be dissolved, such as lack of credit schemes for the farmers, which boost growth and help stabilize farmer organizations

Atlas of Sorghum (\u3ci\u3eSorghum bicolor\u3c/i\u3e (L.) Moench): Production in Eastern and Southern Africa

Grain sorghum (Sorghum bicolor (L.) Moench) is a major crop in many parts of Africa and is noted for its versatility and diversity. It is adapted over a wide range of precipitation and temperature levels and is produced at sea level to above 2000 m altitude. In eastern and southern Africa, it is primarily a crop of resource-poor, small-scale farmers and is typically produced under adverse conditions such as low input use and marginal lands. There are numerous biotic and abiotic constraints to production. The grain and stover are used in many different ways with localized preferences. Much information is needed to effectively address the problems and opportunities of this diverse crop. The Atlas of Sorghum Production in Eastern and Southern Africa presents information on sorghum in nine countries to serve information needs of researchers, extension and rural development specialists, policy makers, and emergency relief personnel. It accounts for 85% of the sorghum production on an area basis, or 3,400,000 ha, from Ethiopia south to Mozambique with most of the uncovered production in Somalia (FAOSTAT, 2008). Numerous researchers and others knowledgeable of sorghum in their country contributed information and expert opinions for the Atlas. The Atlas presents information in maps and tables for 39 sorghum production areas in nine countries addressing production constraints, cropping systems, management, uses, preferences, gender roles, and marketing

Linkages between land management, land degradation, and poverty in Sub-Saharan Africa: The case of Uganda

Poverty reduction and sustainable land management are two objectives that most African countries strive to achieve simultaneously. In designing policies to achieve these objectives concurrently a clear understanding of their linkage is crucial. Yet there is only limited empirical evidence to demonstrate the linkage between poverty and land management in Africa. Using Uganda as a case study, this analysis seeks to better understand this linkage. We used several poverty measures to demonstrate the linkage between poverty and a number of indicators of sustainable land management. In general we found a strong linkage. The results for many poverty indicators give credence to the land degradation–poverty trap, although some indicators showed negative association with land degradation. These results suggest that certain poverty reduction strategies being implemented through agricultural modernization in Africa can achieve win-win-win outcomes, simultaneously increasing productivity, reducing poverty, and reducing land degradation. Examples of such strategies include promoting investments in soil and water conservation and agroforestry. Some strategies—such as road development, encouragement of nonfarm activities, and promotion of rural finance—appear to contribute to positive outcomes without significant tradeoffs. Other strategies are likely to involve trade-offs among different objectives. The presence of such trade-offs is not an argument for avoiding these strategies; rather it suggests the need to recognize and find ways to ameliorate such negative impacts where they occur. For example, incorporating teaching of the principles of sustainable agriculture and land management into educational curricula, and into the technical assistance approach of the National Agricultural Advisory Services and other organizations, is one important way of addressing such trade-offs. Investment in poverty reduction and agricultural modernization by itself is not sufficient to address the problem of land degradation in Uganda; it must be complemented by greater efforts to promote sustainable land management practices

Atlas of Sorghum (Sorghum bicolor (L.) Moench): Production in Eastern and Southern Africa

This Atlas presents information on sorghum (a major crop in many parts of Africa, noted for its versatility and diversity) in nine countries to serve information needs of researchers, extension and rural development specialists, policy makers, and emergency relief personnel. It accounts for 85% of the sorghum production on an area basis, or 3,400,000 ha, from Ethiopia south to Mozambique with most of the uncovered production in Somalia (FAOSTAT, 2008). The Atlas presents information in maps and tables dealing with production constraints, cropping systems, management, uses, preferences, gender roles, and marketing.Dokumentigani wuxuu ka warbixinayaa masaggada laga beero meelo badan oo Afrika ka tirsan. Wuxuu si tifaftiran uga hadlayaa habka loo beerto masaggada iyo waxtarkeeda.Questo atlante presenta dati sul sorgo o sorghum (una delle maggiori colture in molte parti dell'Africa, nota per la sua varietà) in nove paesi per fornire informazioni utili ai ricercatori, agli specialisti di sviluppo rurale, ai politicanti e al personale di pronto soccorso. Rende conto dell'85% della produzione di sorgo su un'area di 3.400.000 ha, dall'Etiopia del sud al Mozambico e la maggior parte della produzione senza copertura in Somalia (FAOSTAT, 2008). L'atlante presenta le informazioni in mappe e tabelle, riguardanti i vincoli produttivi, i sistemi di coltivazione, la gestione, gli usi, le preferenze, i ruoli di genere e il mercato

Data from: Wheat nutrient response functions for the East Africa highlands

Wheat (Triticum æstivum L.) is an important East Africa highland crop but yields are low. Information is scarce for optimization of fertilizer use. Research was conducted to determine yield response functions for N, P and K, and to diagnose Mg–S–Zn–B deficiencies. The average grain yield increase in Rwanda due to N application was 1.5 Mg ha−1 with a mean economically optimal rate (EOR) of 68 kg ha−1 N. In Kenya and Tanzania, yield was increased by 29% with EOR N for two SY but unaffected by N rate for four other SY which on average had 50% of the soil organic C (SOC) as the N-responsive SY. Yield was increased, on average, with application of P and K by 0.47 and 0.23 Mg ha−1, respectively, at EOR in Rwanda but effects were inconsistent for other SY where soil test K was higher than in Rwanda. Application of Mg–S–Zn–B resulted in 0.46 Mg ha−1 more yield in Rwanda but did not affect yield at other SY where the average soil test values for these nutrients was 35% higher than in Rwanda. If the financially constrained farmer opts to apply the affordable fertilizer to twice as much land at 50% EOR compared with 100% EOR, the mean yield increase is reduced by 27% but production and PCR are increased by 43 and 72%, respectively. Nutrient effects were relatively consistent and positive in Rwanda, but less and less inconsistent elsewhere with generally less SOC, more K–Mg–S–Zn–B availability, and often lower yields