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Buah S.,National Agricultural Research Laboratories | Buruchara R.,International Center for Tropical Agriculture | Okori P.,Makerere University
Genetic Resources and Crop Evolution | Year: 2017

Common bean (Phaseolus vulgaris L.) was introduced to East Africa over 400 years ago and is today a fundamental part of food and income security of many smallholder farmers in the region. East Africa is among the top three bean producing and consuming regions of Africa with Uganda, Rwanda and Kenya being leaders in production. The leading common bean producing region in Uganda is the Southwestern (SW) highlands. Production is subsistent and farmers grow mixed varieties (accessions) to minimize losses. The aim of this study was to investigate the impact of farmer selection and production practices on genetic diversity of common bean in SW Uganda. 100 accessions were assembled from SW Uganda and assayed with 6 DNA simple sequence repeat (SSR) markers. A total of 41 alleles were detected giving an overall average gene diversity of 0.299 (30%) in both districts. The accessions clustered into two major gene pools i.e., Mesoamerican and Andean. Within each gene pool there was evidence of clonal populations suggesting wide distribution of certain accessions. Kabale district had a higher average gene diversity (38%) compared to Kisoro district (22%). Detection of Andean phaseolin in a clone set of Mesoamerican gene pool suggests introgession between the two groups. © 2017 Springer Science+Business Media Dordrecht


Tumwesigye K.S.,University College Cork | Tumwesigye K.S.,National Agricultural Research Laboratories | Oliveira J.C.,University College Cork | Sousa-Gallagher M.J.,University College Cork
Trends in Food Science and Technology | Year: 2016

Background Cassava represents a reasonable share in biobased material development globally. The production of its biopolymer derivatives using conventional techniques/methods is accompanied by significant wastes with potential negative environmental impact. Among the biopolymer derivatives, starch dominates as lone additive in cast matrices with packaging limitations, requiring other biopolymer derivatives, and/or external-source modifiers for matrix improvement. Exploiting integrated sustainable engineering process design of all biopolymer derivatives, is a novel approach in designing efficient system of cassava biobased materials for food and non-food applications. Scope and approach A critical review on the current and emerging techniques and methodologies to address cassava wastes and challenges of cassava research for application on biobased packaging are provided. The potential of integrated sustainable engineering process design framework for packaging system is discussed, and prospects for improvement suggested. Key findings and conclusions Challenges of significant waste generated during conventional processing and on the application process aiming at tailoring materials to industrial needs are reported. These materials should be improved using a holistic approach reflecting the target products, variable environment, minimising production costs and energy. Use of novel material resources, eliminating waste, and employing a standardised methodology via desirability optimisation, present a promising process integration tool for development of sustainable cassava biobased systems. © 2016 Elsevier Ltd


PubMed | International Institute Of Tropical Agriculture, Institute dEconomie Rurale, Regional Center, Africa Rice Center and 11 more.
Type: Journal Article | Journal: Proceedings of the National Academy of Sciences of the United States of America | Year: 2016

Although global food demand is expected to increase 60% by 2050 compared with 2005/2007, the rise will be much greater in sub-Saharan Africa (SSA). Indeed, SSA is the region at greatest food security risk because by 2050 its population will increase 2.5-fold and demand for cereals approximately triple, whereas current levels of cereal consumption already depend on substantial imports. At issue is whether SSA can meet this vast increase in cereal demand without greater reliance on cereal imports or major expansion of agricultural area and associated biodiversity loss and greenhouse gas emissions. Recent studies indicate that the global increase in food demand by 2050 can be met through closing the gap between current farm yield and yield potential on existing cropland. Here, however, we estimate it will not be feasible to meet future SSA cereal demand on existing production area by yield gap closure alone. Our agronomically robust yield gap analysis for 10 countries in SSA using location-specific data and a spatial upscaling approach reveals that, in addition to yield gap closure, other more complex and uncertain components of intensification are also needed, i.e., increasing cropping intensity (the number of crops grown per 12 mo on the same field) and sustainable expansion of irrigated production area. If intensification is not successful and massive cropland land expansion is to be avoided, SSA will depend much more on imports of cereals than it does today.


News Article | December 12, 2016
Site: www.eurekalert.org

Lincoln, Nebraska, Dec. 12, 2016 - Maximizing cereal crops yields in sub-Saharan Africa would still fail to meet the region's skyrocketing grain demand by 2050, according to a new study from the University of Nebraska-Lincoln, Wageningen University and multiple African institutions. Sub-Saharan Africa produces about 80 percent of the grain it now consumes. But that consumption could triple if its population rises an expected 250 percent by 2050. Presently, cereal crops account for about half of sub-Saharan Africa's food and farmland. Even if sub-Saharan yields continue rising at the rate they have over the last quarter-century, the region's existing farmland would still produce only between a third and half of the grain needed in 2050, researchers reported Dec. 12 in Proceedings of the National Academy of Sciences. "The status quo is simply not acceptable," said co-author Ken Cassman, professor emeritus at Nebraska and fellow of the Daugherty Water for Food Global Institute. "Complacency is the enemy. This is a clarion call for action."To maintain even 80 percent of its self-sufficiency in 2050, sub-Saharan Africa must reach the realistic yield thresholds of corn, millet, rice, sorghum and wheat, the study found. The region currently grows about a quarter of the cereal crops it could by optimizing its plant and soil management, the authors said. Closing this gap would require what the study called a "large, abrupt acceleration" in yield trajectories similar to the Green Revolution that transformed North American, European and Asian agriculture in the mid-20th century. "But our analysis shows that even closing the gap between potential yields using modern farming practices and current farm yields, with traditional crop varieties and little fertilizer, still leaves the area at a deficit with regard to cereals," Cassman said. "That's quite eye-opening, because my guess is that most people in the agricultural development community might have thought sub-Saharan Africa could be self-sufficient, or even produce excess cereal, if it were able to close existing yield gaps."The authors analyzed 10 sub-Saharan countries using the Global Yield Gap Atlas, which estimates the disparity between actual and potential yields while accounting for differences in soil types and climate. After assembling location-specific data and assessments from agronomists in each of the 10 countries, the team used a novel upscaling technique to estimate yield gaps at national and sub-continental levels. Meeting future cereal demands could depend on expanding responsible irrigation use to raise yield ceilings and stabilize cereal production, said Kindie Tesfaye, agronomist with the International Maize and Wheat Improvement Centre in Ethiopia. Recent analyses have documented regional aquifers that could become sources of sustainable irrigation, though the authors emphasized the importance of withdrawing only what can be replenished by rainfall and recharge. Tesfaye said irrigation could ramp up yield thresholds by allowing farmers to annually grow a crop multiple times in the same field or introduce new cereals into yearly planting schedules. Patricio Grassini, assistant professor of agronomy and horticulture at Nebraska, stressed that these efforts will require "massive and strategic investments in agricultural development on an unprecedented level." Combining the yield gap findings with socioeconomic and other data, Grassini said, could inform essential upgrades to infrastructure that might include roads and water pipelines; publicly financed research and development; and farmer access to credit, state-of-the-art equipment and pest-management resources. A failure to upgrade could force sub-Saharan Africa to transform savannahs, rainforests or other natural ecosystems into farmland - a process, the study noted, that would produce massive amounts of greenhouse gases while shrinking the habitats of native plant and animal species. If yield growth and cropland distribution remained constant across the 10 countries, seven would lack the land area to accommodate such expansion, said Abdullahi Bala, professor at Nigeria's Federal University of Technology, Minna. And the newly converted land would very likely prove less fertile than the region's current farmland, Cassman said. Though the region might also resort to importing cereal crops, the authors cautioned that many of the developing countries in sub-Saharan Africa could struggle to do so. The price spikes that often accompany drought-driven market shortages could further complicate matters. "If it is true that sub-Saharan Africa will depend more heavily on food imports," Grassini said, "the next question is: What would be the infrastructure networks needed to alleviate food shortages in the most vulnerable areas?" The researchers said several sub-Saharan countries may produce surpluses that could be shared among neighbors. Though the projected surpluses would fall short of compensating for neighboring deficits,this represents one of several opportunities the region might seize to contend with the profound challenges ahead. "To reach those goals is going to take very strategic, careful prioritization and adequate resources to do the job," Cassman said. "Having a strategic vision of what to invest in - to fund those things that can give greatest payoff - is critical. What this work does is allow for a much more surgical look at how to do that, which just wasn't possible before." The Daugherty Water for Food Global Institute, the Bill and Melinda Gates Foundation, USAID and the university supported the development of the Global Yield Gap Atlas, which agronomists at Nebraska and Wageningen created in 2011. The new study was co-authored by agronomists at the International Crops Research Institute for the Semi-Arid Tropics (Kenya); International Food Policy Research Institute; Africa Rice Center (Benin); Jomo Kenyatta University of Agriculture and Technology (Kenya); International Institute of Tropical Agriculture (Ghana); AGRHYMET Regional Centre (Niger); Federal University of Technology, Minna (Nigeria); University of Zimbabwe; National Agricultural Research Laboratories (Uganda); Institute of Rural Economy (Mali); Ministry of Agriculture Food and Cooperatives (Tanzania); Environmental and Agricultural Research Institute (Burkina Faso); and the International Maize and Wheat Improvement Centre (Ethiopia).


Mulumba J.W.,Plant Genetic Resources Center | Lwasa J.,National Agricultural Research Laboratories | Atieno F.,Bioversity International
African Journal of Ecology | Year: 2011

The aim of the study was to map the distribution of Acacia senegal and its infraspecific taxa in Uganda and predict its suitable range of occurrence based on climatic factors. The distribution of the infraspecific taxa was analysed for richness, diversity, turnover and reserve selection. Regression analysis was performed to understand the relationship between distribution of the species and climatic variables. Georeferenced species occurrence points were superimposed over temperature and vapour maps. Areas with highest taxa richness, diversity and turnover were mapped and found in the Lake Kyoga basin. The species shows preference for the northern region of the study area with dissimilar climatic pattern from the southern region and the superimposition supported findings. Variety kerensis exhibited narrower climatic, altitudinal and distribution range preference. Temperature seasonality, maximum temperature of warmest month, temperature annual range, mean temperatures of warmest and driest quarters had the highest coefficients of determination (r2>0.7) hence most important in influencing species distribution. The most appropriate locations for in situ conservation and for germplasm collection to ensure maximum diversity is secured are found in Wabisi-Wajala, Kiula, Kyalubanga, Bajo, Kasagala, Kabwika-mujwalanganda, Maruzi, Moroto and Napak Central Forest Reserves. The study recommends ecological studies to understand status of A. senegal. © 2011 Blackwell Publishing Ltd.


Kovacs G.,Catholic University of Leuven | Sagi L.,Catholic University of Leuven | Sagi L.,Hungarian Academy of Sciences | Jacon G.,Catholic University of Leuven | And 8 more authors.
Transgenic Research | Year: 2013

Transgenic banana (Musa acuminata 'Gros Michel') integrating either of two rice chitinase genes was generated and its resistance to Black Leaf Streak disease caused by the fungus Mycosphaerella fijiensis was tested using a leaf disk bioassay. PCR screening indicated the presence of the hpt selectable marker gene in more than 90 % of the lines tested, whereas more than three quarters of the lines contained the linked rice chitinase gene resulting in a co-transformation frequency of at least 71.4 %. Further, a unique stable integration of the transgenes in each line revealed some false negative PCR results and the expected co-transformation frequency of 100 %. The transgene insert number per line ranged from 1 to 5 and single transgene insert lines (25 % of all) were identified. Considerable delay in disease development (up to 63 days post-incoculation) over a monitoring period of 108 days occurred in nine lines with extracellularly targeted chitinase out of 17 transgenic lines tested and their necrotic leaf area decreased by 73-94 % compared to the untransformed susceptible control line. Finally, correlation between symptom development and rice chitinase expression was confirmed in two lines by Western analysis. The potential of rice chitinase genes to enhance resistance against M. fijiensis in banana was demonstrated as well as the usefulness of the leaf disk bioassay for early disease screening in transgenic banana lines. © 2012 The Author(s).


Tumuhimbise R.,National Agricultural Research Laboratories
Journal of Crop Improvement | Year: 2015

Taro is a marginalized tuber food crop, with wide distribution in the tropics. This study was aimed at assessing the effects of plant spacing and planting depth on corm yield and yield-related traits in taro. Dasheen, a predominant taro cultivar in Uganda, was sourced from farmers’ fields and evaluated using a randomized complete block design for two seasons. Three plant spacings (0.30 × 0.30 m, 0.50 × 0.50 m, 0.75 × 0.75 m) and two planting depths (0.15 m and 0.30 m) were used. Plant spacing had a significant effect on plant height, corm girth, corm yield plant−1, shoot yield plant−1 and corm yield hectare−1 (ha−1). Planting depth had a significant effect on corm length and corm yield ha−1. The widest spacing (0.75 × 0.75) produced largest corm yield plant−1 and shoot yield plant−1, whereas the narrowest spacing (0.30 × 0.30 m) produced largest shoot yield ha−1 and corm yield ha−1. Planting depth of 0.30 m produced higher corm yield and length than that of 0.15 m. Plant spacing was positively and significantly correlated with plant height, corm girth, and shoot yield plant−1 but negatively correlated with corm yield ha−1 and shoot yield ha−1. Planting depth was positively and significantly correlated with corm length, indicating that deeper planting of taro produced longer corms, thus enhancing corm yield. Copyright © Taylor & Francis Group, LLC.


Tomlins K.,University of Greenwich | Owori C.,National Agricultural Research Laboratories | Bechoff A.,University of Greenwich | Menya G.,National Agricultural Research Laboratories | Westby A.,University of Greenwich
Food Chemistry | Year: 2012

The sensory characteristics of biofortified sweet potato in Africa were explored over a wide range of carotenoid (0.4-72.5 μg/g fresh weight) and dry matter contents (26.8-39.4%). The logarithm of the total carotenoid content was correlated with the dry matter content (declining by 1.2% with each doubling of the carotenoid content) and a wide range of sensory characteristics that involve visual, odour, taste and textural characteristics. Multiple linear regression models were developed. The logarithmic relationship of colour to the carotenoid concentration means that those varieties with a relatively low carotenoid content may appear to be of similar intensity to those with a much higher and hence nutritionally beneficial carotenoid content. © 2011 Elsevier Ltd. All rights reserved.


Namanya P.,National Agricultural Research Laboratories | Mutumba G.,Makerere University | Magambo S.M.,Makerere University | Tushemereirwe W.,National Agricultural Research Laboratories
In Vitro Cellular and Developmental Biology - Plant | Year: 2014

Embryogenic cell suspensions of triploid East African Highland bananas (Musa AAA-EA) were initiated and generated using cooking cultivar ‘Nakyetengu’ belonging to the Nakabululu clone set. Immature male flowers produced embryogenic calli consisting of embryos and friable tissue after 4 mo culture on a modified MA1 callus induction medium. Friable calli were initiated and maintained in liquid MA2 medium. A cell growth rate of 1.5–2.0 sedimented cell volume (SCV) per month was observed. Embryo development was observed at 2.18 × 103 embryos per mL SCV. Germination of these embryos was observed at 2.8% and 6.2% for two cell suspension lines. Plant regeneration efficiency was 60–100%, all producing normal plants with a shoot and roots at weaning. In the field, somatic cell-derived plants were all normal morphology and comparable to control plants during vegetative and reproductive stages. This study is a breakthrough for recalcitrant East African Highland banana and offers a system that can provide essential raw materials for associated germplasm improvement through genetic engineering approaches. © 2014, The Society for In Vitro Biology.


PubMed | International Center for Tropical Agriculture, National Agricultural Research Laboratories, Kampala University and Copenhagen University
Type: | Journal: Microbiological research | Year: 2016

Xanthomonas campestris pv. musacearum (Xcm) causing the banana Xanthomonas wilt (BXW) disease has been the main xanthomonad associated with bananas in East and Central Africa based on phenotypic and biochemical characteristics. However, biochemical methods cannot effectively distinguish between pathogenic and non-pathogenic xanthomonads. In this study, gram-negative and yellow-pigmented mucoid bacteria were isolated from BXW symptomatic and symptomless bananas collected from different parts of Uganda. Biolog, Xcm-specific (GspDm), Xanthomonas vasicola species-specific (NZ085) and Xanthomonas genus-specific (X1623) primers in PCR, and sequencing of ITS region were used to identify and characterize the isolates. Biolog tests revealed several isolates as xanthomonads. The GspDm and NZ085 primers accurately identified three isolates from diseased bananas as Xcm and these were pathogenic when re-inoculated into bananas. DNA from more isolates than those amplified by GspDm and NZ085 primers were amplified by the X1623 primers implying they are xanthomonads, these were however non-pathogenic on bananas. In the 16-23 ITS sequence based phylogeny, the pathogenic bacteria clustered together with the Xcm reference strain, while the non-pathogenic xanthomonads isolated from both BXW symptomatic and symptomless bananas clustered with group I xanthomonads. The findings reveal dynamic Xanthomonas populations in bananas, which can easily be misrepresented by only using phenotyping and biochemical tests. A combination of tools provides the most accurate identity and characterization of these plant associated bacteria. The interactions between the pathogenic and non-pathogenic xanthomonads in bananas may pave way to understanding effect of microbial interactions on BXW disease development and offer clues to biocontrol of Xcm.

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