Posts Tagged ‘sub-Saharan Africa’

Drought tolerant maize for farmer adaptation to drought in sub-Saharan Africa : determinants of adoption in eastern and southern Africa

Posted by gabrielamartinez on , in Journal Articles

56914Author: Fisher, M., Tsedeke Abate; Lunduka, R.; Asnake, W.; Alemayehu, Y.; Madulu, R.B.

Published in: Climatic Change, In press


 

In sub-Saharan Africa (SSA), Bmaize is life,^ due to its importance to food security and economic wellbeing. Around 40 % of Africa’s maize-growing area faces occasional drought stress, resulting in yield losses of 10–25 %. Around 25 % of the maize crop suffers frequent drought, with losses of up to half the harvest. To reduce vulnerability and improve food security, the Drought Tolerant Maize for Africa (DTMA) project has made releases of 160 drought tolerant (DT) maize varieties between 2007 and 2013. These have been tested in experimental and farmers’ fields, and disseminated to farmers in 13 African countries through national agricultural research systems and private seed companies. Yields of the new varieties are superior to those of currently available commercial maize varieties under both stress and optimum growing conditions. Although the benefits of DT maize for African farmers have been repeatedly predicted, realization of those benefits depends on farmer uptake, which has received limited empirical study. We use new plot-level data from surveys of 3,700 farm households in six countries (Ethiopia, Tanzania, Uganda, Malawi, Zambia, and Zimbabwe) to country variation in farmer uptake of DT maize, from 9 % of maize plots in Zimbabwe to 61% in Malawi. The major barriers to adoption include unavailability of improved seed, inadequate information, lack of resources, high seed price, and perceived attributes of different varieties. Based on the results, we recommend that seed companies and agro-dealers ensure adequate supply of DT maize seed in local markets and sell seed in affordable micro-packs (1 or 2 kg). Furthermore, the DTMA project and partners should ramp up promotional efforts to ensure widespread awareness and understanding of the benefits of the new DT maize varieties.

Production risks and food security under alternative technology choices in Malawi: application of a multinomial endogenous switching regression

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Agricultural Economics, 2014.

Kassie, M.; Adefris Teklewold; Marenya, P.; Jaleta Debello Moti; Erenstein, O.

Employing nationally representative data, we investigate the impact of Sustainable Intensification Practices (SIPs) on farm households’ food security, downside risk and the cost of risk in Malawi. The analysis relies on a flexible moment-based specification of a stochastic production function in a multinomial endogenous switching regression framework to correct for the selection bias stemming both from observed and unobserved heterogeneity. A quantile moment approach is used to estimate the cost of risk. After controlling for the effects of unobserved heterogeneity and several observable variables on maize production and downside risk functions, estimation results show that the adoption of SIPs increases food security and reduces downside risk exposure and the cost of risk. We estimate greater food security and larger reduction in downside risk from simultaneous adoption of both crop diversification (maize–legume intercropping and rotations) and minimum tillage, suggesting that there are complementary benefits from these practices. We find most of the cost of risk comes from exposure to downside risk. Our findings imply that in dealing with production risks development agents should encourage the adoption of agronomic and resource-management practices along with other risk mitigation and food security improving strategies.

Identifying secure and low carbon food production practices: A case study in Kenya and Ethiopia

Posted by Carelia Juarez on , in Journal Articles

Published in Agriculture, Ecosystems and Environment 197 : 137-146, 2014

Bellarby, J.;  Stirling, C.; Vetter, S.H.; Berresaw Menale Kassie; Kanampiu, F.; Sonder, K.; Smith, P.; Hillier, J.

The world population is projected to increase to 9–10 billion by 2050, during which time it will be necessary to reduce anthropogenic greenhouse gas emissions to mitigate climate change. The particular challenge this places on agriculture is to identify practices which ensure stable and productive food supply that also have a low greenhouse gas (GHG) intensity. Maize is the principle staple crop in many parts of Africa with low and variable yields, averaging only 1.6 t/ha in sub-Saharan Africa (SSA). Food security and increasing crop yields are considered priorities in SSA over impacts of food production on GHG emissions. Here we describe an approach that can be used to inform a decision support tree for optimal interventions to obtain sufficient food production with low GHG intensity, and we demonstrate its applicability to SSA. We employed a derivative of the farm greenhouse gas calculator ‘Cool Farm Tool’ (CFT) on a large survey of Kenyan and Ethiopian smallholder maize-based systems in an assessment of GHG intensity. It was observed that GHG emissions are strongly correlated with nitrogen (N) input. Based on the relationship between yield and GHG emissions established in this study, a yield of 0.7 t/ha incurs the same emissions as those incurred for maize from newly exploited land for maize in the region. Thus, yields of at least 0.7 t/ha should be ensured to achieve GHG intensities lower than those for exploiting new land for production. Depending on family size, the maize yield required to support the average consumption of maize per household in these regions was determined to be between 0.3 and 2.0 t/ha, so that the desirable yield can be even higher from a food security perspective. Based on the response of the observed yield to increasing N application levels, average optimum N input levels were determined as 60 and 120 kg N/ha for Kenya and Ethiopia, respectively. Nitrogen balance calculations could be applied to other countries or scaled down to districts to quantify the trade-offs, and to optimise crop productivity and GHG emissions.

Managing vulnerability to drought and enhancing livelihood resilience in sub-Saharan Africa: Technological, institutional and policy options

Posted by Carelia Juarez on , in Journal Articles

Published in Weather and Climate Extremes 67-79, 2014

 Shiferaw, B.Kindie Tesfaye FantayeBerresaw Menale KassieAbate, T.Prasanna, B.M.Menkir, A. 

Agriculture and the economies of Sub-Saharan Africa (SSA) are highly sensitive to climatic variability. Drought, in particular, represents one of the most important natural factors contributing to malnutrition and famine in many parts of the region. The overall impact of drought on a given country/region and its ability to recover from the resulting social, economic and environmental impacts depends on several factors. The economic, social and environmental impacts of drought are huge in SSA and the national costs and losses incurred threaten to undermine the wider economic and development gains made in the last few decades in the region. There is an urgent need to reduce the vulnerability of countries to climate variability and to the threats posed by climate change. This paper attempts to highlight the challenges of drought in SSA and reviews the current drought risk management strategies, especially the promising technological and policy options for managing drought risks to protect livelihoods and reduce vulnerability. The review suggests the possibilities of several ex ante and ex post drought management strategies in SSA although their effectiveness depends on agro-climatic and socio-economic conditions. Existing technological, policy and institutional risk management measures need to be strengthened and integrated to manage drought ex ante and to minimize the ex post negative effects for vulnerable households and regions. A proactive approach that combines promising technological, institutional and policy solutions to manage the risks within vulnerable communities implemented by institutions operating at different levels (community, sub-national, and national) is considered to be the way forward for managing drought and climate variability.

Genetic relationships and structure among open-pollinated maize varieties adapted to eastern and southern Africa using microsatellite markers

Posted by Carelia Juarez on , in Journal Articles

Published in Molecular Breeding, 2014

Fentaye Kassa SemagnMagorokosho, C.Ogugo, V.Makumbi, D.Warburton, M.L.

Molecular characterization of open-pollinated maize varieties (OPVs) is fundamentally important in maize germplasm improvement. We investigated the extent of genetic differences, patterns of relationships, and population structure among 218 diverse OPVs widely used in southern and eastern Africa using the model-based population structure, analysis of molecular variance, cluster analysis, principal component analysis, and discriminant analysis. The OPVs were genotyped with 51 microsatellite markers and the fluorescent detection system of the Applied Biosystems 3730 Capillary Sequencer. The number of alleles detected in each OPV varied from 72 to 155, with an overall mean of 127.6. Genetic distance among the OPVs varied from 0.051 to 0.434, with a mean of 0.227. The different multivariate methods suggest the presence of 2–4 possible groups, primarily by maturity groups but also with overlapping variation between breeding programs, mega-environments, and specific agronomic traits. Nearly all OPVs in group 1 and group 2 belong to the intermediate-late and early maturity groups, respectively. Group 3 consisted of mainly intermediate maturing OPVs, while group 4 contained OPVs of different maturity groups. The OPVs widely used in eastern Africa either originated from the southern African maize breeding programs, or the majority of inbred lines used as parents by the two breeding programs in developing the OPVs might be genetically related. Some of the OPVs are much older than others, but they still did not show a clear pattern of genetic differentiation as compared with the recently developed ones, which is most likely due to recycling of the best parental lines in forming new OPVs.

Combining ability of maize (Zea mays) inbred lines resistant to Striga hermonthica (Del.) Benth evaluated under artificial Striga infestation

Posted by Carelia Juarez on , in Journal Articles

Published in African Journal of Agricultural Research 9 (16) : 1287-1295, 2014

Karaya, H.Njoroge, K.Mugo, S.Ariga, E.S.Kanampiu, F.Nderitu, J. 

The parasitic weed Striga affects maize on an estimated 20 million ha in Africa, making it a major cause of maize yield reduction from near world average of 4.2 t/ha few decades ago to the present 1.5 t/ha. The objectives of this study were to examine the combining ability of 20 inbred lines and identify single crosses which can be used to develop other hybrids resistant to Striga hermonthica (Del.) Benth. Fourteen female lines were mated using North Carolina Design II with all six males. The resulting 84 F1s along with six commercial checks were evaluated in four separate trials for two rainy seasons during 2010. The trials were conducted on station under both artificial Striga infestation and Striga free environments using standard procedures at the Kibos and Alupe sites, both in the Kenya’s Lake Victoria Basin. Data were recorded on Striga counts, Striga damage rating (SDR), grain yield and other agronomic traits. General combining ability (GCA) and specific combining ability (SCA) effects were computed using SAS. The new F1 hybrids outperformed the commercial checks in grain yield and reaction to Striga. Single crosses JI-30-3/TESTR 151, JI-30-18/TESTR 151, CML206//56/44-6-3-7-1/TESTR 149 and JI-30-18/TESTR 156 gave the highest yield while single cross JI10-28-#/TESTR 136 gave the lowest yield. The ratio of GCA: SCA mean squares exhibited a predominance of additive gene effects in the inheritance of Striga resistance traits as opposed to dominance gene effects. Inbred lines with good GCA for yield and Striga resistance traits were identified as TESTR 151, TESTR 156 and OSU231//56/44-6-4-17-3. The high GCA inbred lines and the superior single crosses will provide a basis for future use perse and also development of three-way and double cross hybrids to be grown in Striga prone areas of the Lake Victoria Basin in eastern Africa.

Understanding the impact and adoption of conservation agriculture in Africa: A multi-scale analysis

Posted by Carelia Juarez on , in Journal Articles

Published in  Agriculture, Ecosystems and  Environment, 2013

Corbeels, M.; Graaff, Jan de; Ndah, T.H.; Penot, E.; Baudron, F.; Naudin, K.; Andrieu, N.; Chirat, G.; Schuler, J.; Nyagumbo, I.; Rusinamhodzi, L.;Traore, K.; Mzoba, H.D.; Adolwa, I.S.

Conservation agriculture (CA) is increasingly promoted in Africa as an alternative for coping with the need to increase food production on the basis of more sustainable farming practices. Success with adopting CA on farms in Africa has been limited, despite more than two decades of research and development investments. Through analyzing past and on-going CA experiences in a set of case studies, this paper seeks to better understand the reasons for the limited adoption of CA and to assess where, when and for whom CA works best. CA is analyzed and understood within a framework that distinguishes the following scales of analysis: field, farm, village and region. CA has a potential to increase crop yields in the fields, especially under conditions of erratic rainfall and over the long-term as a result of a gradual increase of overall soil quality. The impact on farm income with the practice of CA on some fields of the farm is far less evident, and depends on the type of farm. The lack of an immediate increase in farm income with CA explains in many cases the non-adoption of CA. Smallholders have often short-term time horizons: future benefits do not adequately outweigh their immediate needs. Another key factor that explains the limited CA adoption in mixed crop-livestock farming systems is the fact that crop harvest residues are preferably used as fodder for livestock, preventing their use as soil cover. Finally, in most case studies good markets for purchase of inputs and sale of produce – a key prerequisite condition for adoption of new technologies – were lacking. The case studies show clear evidence for the need to target end users (not all farmers are potential end user of CA) and adapt CA systems to the local circumstances of the farmers, considering in particular the farmer’s investment capacity in the practice of CA and the compatibility of CA with his/her production objectives and existing farming activities. The identification of situations where, when and for whom CA works will help future development agents to better target their investments with CA.

Adapting maize production to climate change in sub-Saharan Africa

Posted by Carelia Juarez on , in Journal Articles

Published in Food Security, 2013

Jill E. Cairns, Jon Hellin, Kai Sonder, José Luis Araus, John F. MacRobert, Christian Thierfelder and  B. M. Prasanna

Given the accumulating evidence of climate change in sub-Saharan Africa, there is an urgent need to develop more climate resilient maize systems. Adaptation strategies to climate change in maize systems in sub-Saharan Africa are likely to include improved germplasm with tolerance to drought and heat stress and improved management practices. Adapting maize systems to future climates requires the ability to accurately predict future climate scenarios in order to determine agricultural responses to climate change and set priorities for adaptation strategies. Here we review the projected climate change scenarios for Africa’s maize growing regions using the outputs of 19 global climate models. By 2050, air temperatures are expected to increase throughout maize mega- environments within sub-Saharan Africa by an average of 2.1°C. Rainfall changes during the maize growing season varied with location. Given the time lag between the development of improved cultivars until the seed is in the hands of farmers and adoption of new management practices, there is an urgent need to prioritise research strategies on climate change resilient germplasm development to offset the predicted yield declines.

 

Striga hermonthica parasitism in maize in response to N and P fertilisers

Posted by Carelia Juarez on , in Journal Articles

Published in Field Crops Research 134 (12): 1-10, 2012

M. Jamil, F.K. Kanampiu, H. Karaya, T. Charnikhova, H.J. Bouwmeester

Parasitism by the parasitic weed, Striga hermonthica (Striga), constitutes a major biological constraint to maize production in sub-Sahara Africa. Nutrient deficiency is known to aggravate Striga infestation and in a number of plant species it was recently shown that this may be due to increased secretion of Strigagermination stimulants into the soil. The present study was designed to observe the connection between soil fertility, secretion of germination stimulants and Striga infection in maize under greenhouse and field conditions. The experiments were conducted during two successive cropping seasons (2008 and 2009). The greenhouse study showed that maize secretes a number of so far unidentified strigolactones that induceStriga seed germination and the amount of these strigolactones increases upon N and P deficiency. The increased secretion of germination stimulants under N and P deficiency resulted in increased Striga infection in pot experiments. The on-station and on-farm field trials in Western Kenya also showed reduction in Strigainfestation with the application of mineral nutrients but the results were less consistent than in the greenhouse. Increasing levels of N showed a fair reduction of Striga in the field especially during the first year, whereas P application did not have much effect in contrast to the greenhouse study where both N and P clearly reduced Striga infection. The likely explanation for this discrepancy is that availability of mineral nutrients under field conditions is less predictable than under greenhouse conditions, due to a number of factors such as soil texture and structure, pH, salinity, drought, leaching and runoff. Hence, further studies are needed on the importance of these factors before a fertiliser application strategy can be formulated to improve control of Striga in maize in the field.

Maize Production in a Changing Climate: Impacts, Adaptation, and Mitigation Strategies

Posted by Carelia Juarez on , in Journal Articles

Published in  Advances in Agronomy 114: 1-58, 2012

J.E. Cairns, K. Sonder, P.H. Zaidi, N. Verhulst, G. Mahuku, R. Babu, S.K. Nair, B. Das, B. Govaerts, M.T. Vinayan, Z. Rashid, J.J. Noor, P. Devi, F. San Vicente and B.M. Prasanna

Plant breeding and improved management options have made remarkable progress in increasing crop yields during the past century. However, climate change projections suggest that large yield losses will be occurring in many regions, particularly within sub-Saharan Africa. The development of climate-ready germplasm to offset these losses is of the upmost importance. Given the time lag between the development of improved germplasm and adoption in farmers’ fields, the development of improved breeding pipelines needs to be a high priority. Recent advances in molecular breeding provide powerful tools to accelerate breeding gains and dissect stress adaptation. This review focuses on achievements in stress tolerance breeding and physiology and presents future tools for quick and efficient germplasm development. Sustainable agronomic and resource management practices can effectively contribute to climate change mitigation. Management options to increase maize system resilience to climate-related stresses and mitigate the effects of future climate change are also discussed.