Cassava mosaic disease resistant clones’ growth and yield are prone to early drought stress

Open Access JournalThis study was conducted to evaluate the growth and yield stability of cassava mosaic disease (CMD) resistant breeding populations clones against early drought. Field trials were planted using 200 CMD resistant clones and 7 local landraces in a randomised complete block design with 3 replicates at the International Institute of Tropical Agriculture (IITA) station, Sendusu in Namulonge (Central Uganda) during the second rains of 2006 (2006B) and the first rains of 2007 (2007A). The 2007A crop suffered from drought stress in the first 4 months after planting (MAP). Data were taken on the leaf lobe length and width at 6 MAP and plant height at 12 MAP. Harvest was done at 12 MAP during which the number of storage roots per plant and storage root yield were recorded. Data were analysed using the Mann-Whitney U test to compare crop performance between the 2 seasons. The 2006B crop had significantly (P<0.01) longer leaf lobes, taller plant heights, higher number of storage roots per plant and higher storage root yield than the 2007A crop. There was no significant difference in the leaf lobe width. In this experiment, it was observed that the CMD resistant breeding clones were susceptible to early drought and thus it was recommended that selections should be done for higher water use efficiency

Towards understanding factors that govern fertilizer response in casave: lessons from East Africa

Information on fertilizer response in cassava in Africa is scarce. We conducted a series of on-farm and on-station trials in two consecutive years to quantify yield responses of cassava to mineral fertilizer in Kenya and Uganda and to evaluate factors governing the responses. Average unfertilized yields ranged from 4.2 to 25.7 t ha-1 between sites and years. Mineral fertilizer use increased yields significantly, but response to fertilizer was highly variable (-0.2 to 15.3 t ha-1). Average yield response per kg applied nutrient was 37, 168 and 45 and 106, 482 and 128 kg fresh yield per kg of applied N, P and K, respectively in 2004 and 2005. Fertilizer response was governed by soil fertility, rainfall and weed management, but was not influenced by variety, pest and disease pressure and harvest age. Relative N and K yields were positively correlated to SOC and exchangeable K, while response to fertilizer decreased on more fertile soils. Still, fertilizer response varied widely on low fertility soils (e.g. on soils wit

Ex-ante Evaluation of Cassava Research for Development in Malawi: A Farm Household and Random Utility Modeling Approach

Ex ante evaluation of agricultural research for development projects has become important in recent years for priority setting, ex post impact assessment and learning about generalizability to other populations and contexts. We apply farm household and random utility modeling to baseline survey data and evaluate the impact of a cassava research for development project in Malawi prior to its implementation. The project is being implemented to unlock the potential of cassava in response to the global food crisis. We find that a high proportion of farm households are not self-sufficient in food production and can be assisted by increasing the productivity of land and labor in production, processing and marketing of cassava to reduce deficits and increase marketed surplus. The research for development embeds research in an innovation systems network and speeds up exposure, awareness, adoption and diffusion. This increases the likelihood that incremental benefits will be generated and accrue earlier compared to the counterfactual without the project.Resource /Energy Economics and Policy,

Economic impacts of cassava research and extension in Malawi and Zambia

This paper estimates the economic impacts of cassava research and extension in Malawi and Zambia over the period 1990-2008. The data come from sample household surveys, planting material production records, and a series of cassava improvement experiments conducted in the two countries. Past investments in cassava improvement have led to the development and release of a good number of high-yielding and cassava mosaic virus disease (CMD)-tolerant cassava varieties. The results show relatively higher adoption rates for the CMD-free local varieties compared to CMD-tolerant varieties that have been released in the two countries. The adoption of new varieties has been low and slow largely due to the fact that most of these varieties lacked the consumption attributes highly valued by farmers. The multiplication and distribution of CMD-free planting materials of the recommended local varieties led to greater adoption, but infection with CMD three to four years after adoption meant that the yield gains and economic benefits could not be sustained. Nevertheless, the multiplication and distribution of clean cassava planting materials generated a modest rate of return of 24%, which is actually consistent with an earlier rate of return estimate of 9 to 22% for cassava improvement in developing countries. Analysis of the ex ante impacts of current and future investments in cassava improvement shows that cassava improvement research that focuses on the development and dissemination of varieties with highly preferred consumption and industrial attributes would yield a greater rate of return of 40%

Aflatoxins contamination in processed cassava in Malawi and Zambia

Strains of the Aspergillus fungi, especially A. flavus and A. parasiticus, primarily produce aflatoxins which are a major health concern to man and livestock because of their acute and chronic health effects. Aflatoxins pose the greatest risk to health in tropical Africa because of their widespread prevalence and high toxicity; carcinogenic (cause liver and esophageal cancer) effect, immune system suppressing and anti-nutritional  contaminants in many food commodities and even cause death. Aflatoxins have also been reported to compromise vaccine efficacy in experimental animals. Due to the seriousness of aflatoxins, international agencies have restricted levels of aflatoxins to 20 ppb in food materials as the maximum permissible level in the United States and 4 ppb total aflatoxins and under 2 ppb aflatoxin B1 in Europe. These regulations directed at minimizing human exposure to aflatoxins results in severe economic loss to producers, processors and marketers of the contaminated crop. A study was conducted in Malawi and Zambia to assess the level of fungal and mycotoxins’ contamination in commonly processed cassava products. A total of 92 and 88 samples of processed cassava products comprising makaka, flour, kanyakaska, kadonoska, scrapes and grates were collected in the rainy season of 2008 and 2009 in Malawi, respectively. Further, 22 samples of processed cassava products comprising dried cassava chips and flour were collected in the rainy season of 2009 in Zambia. The samples were analyzed for fungal and aflatoxins B1, B2, G1 and G2 contamination using the Romer mini-column method and the VICAM AflaTest  immunoaffinity fluorometric method. None of the samples in 2008 were contaminated with aflatoxins. Similar results were obtained in 2009 with almost all the samples in Malawi and Zambia having aflatoxin levels much lower (&lt;2.0 ìg/kg in Malawi and &lt;4.2 ìg/kg in Zambia) than the Codex Alimentarius Commission (CAC) maximum permissible level of aflatoxins of 10.0 ìg/kg, implying that the cassava products analyzed were safe for human consumption. However, further studies are needed to cover a larger sample size over a period of a year to represent all seasons in the cassava producing and consuming areas and conclusively make certain the safety of these products for human consumption.Key words: Cassava, consumption, aflatoxin, food, safet

Cassava response to the integrated use of manure and NPK fertilizer in Zambia

Open Access JournalCassava is Africa's second most important food source in terms of calories consumed per capita. However, farmers use little or no fertilizer on cassava and scant information is available regarding the cassava yield response to mineral and organic fertilizer inputs in Zambia. This study was undertaken to determine the response of cassava to the integrated use of organic and inorganic nutrient sources in two contrasting agroecological zones of Zambia; Mansa located in Zone III and Kabangwe located in Zone II. The treatments consisted of a factorial combination of four NPK rates (unfertilized control, 50N-11P-41.5K, 100N-22P-83K, and 150N-33P-124.5K kg/ha) with four rates of chicken manure (0, 1.4, 2.8, and 4.2 t/ha). The treatments were laid out in a randomized complete block design with three replications. Cassava height, stem girth, canopy diameter, leaf area index, and chlorophyll index were monitored over time and roots were harvested at 12 months after planting (MAP). Growth parameters and yield varied significantly (p < 0.01) both with NPK, manure application, and their interaction effects at 12 MAP. The combined application of 4.2 t/ha of chicken manure and 100N-22P-83 K kg/ha of mineral fertilizer resulted in the highest yields of 35.2 t/ha at Kabangwe. But, the highest average yield of 34.4 t/ha was recorded with the application of 2.8 t/ha manure and 100N-22P-83 K kg/ha mineral fertilizer at Mansa. This increased treatment yield by 24 and 29% over the sole NPK fertilizer application at Mansa and Kabangwe sites, respectively. Harvest index (HI) was higher when 2.8 t/ha chicken manure was applied in combination with 50N-11P-41.5K kg/ha at Kabangwe. But, the highest HI at Mansa site was achieved with the combination of 2.8 t/ha manure and 100N-22P-83 K kg/ha. This combination also resulted in the highest agronomic efficiency of N, P and K at both sites. It is concluded that cassava productivity and nutrient use efficiency can be improved through the integrated use of NPK and manure in Zambia

Evaluation of cassava processing and utilization at household level in Zambia

Open Access Article; Published online: 15 Jan 2019Cassava (Manihot esculenta Crantz) is the second most consumed staple food crop after maize in Africa and is the main food security crop after maize in Zambia. A study, aimed at analyzing cassava processing and utilization at household level in Zambia, was conducted. Surveys were conducted in five districts (Kasama, Samfya, Mansa, Serenje and Kaoma). A structured questionnaire was administered to a total of 300 randomly selected households. The percentage of households that were involved in processing were 4.3% for income, 34% for consumption and 58% for both income generation and consumption. Levels of awareness and usage of improved cassava processing methods across the districts were low, ranging between 20% and 26%. The only improved processing equipment that farmers used often (69%) was the hammer mill. Product development and utilization were still at a low level (ranging between 9% and 18%) in Zambia. Cassava is mostly consumed in its traditional form for its leaves, as a snack, and for preparing nshima (cassava flour alone or a mixture of cassava and maize meal, called maize-cassava nshima). The limited knowledge of cassava products’ diversity and the low usage of improved equipment are challenges to the production of confectionery products that could lead to increased cassava consumption. There has been no significant change over the last two decades in cassava processing and product development, which could spur cassava development. This calls for more efforts to support Government policy in diversifying crop use and crop diversification in order to create wealth