scholarly journals Genetic diversity of aflatoxin-producing Aspergillus flavus isolated from groundnuts in selected agro-ecological zones of Uganda

2019 ◽  
Author(s):  
Amos Acur ◽  
Renée S. Arias ◽  
Steven Odongo ◽  
Samuel Tuhaise ◽  
Joseph Ssekandi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Aspergillus Flavus ◽  
Lake Victoria ◽  
Farming System ◽  
Aspergillus Species ◽  
Lake Victoria Basin ◽  
West Nile ◽  
Ecological Zones ◽  
Post Harvest ◽  
Agro Ecological Zones

Abstract Background Aspergillus is the main fungal genus causing pre- and post-harvest contamination of groundnuts. Aspergillus flavus belongs to section Flavi, a group consisting of both the aflatoxigenic species (A. flavus, A. parasiticus and A. nomius) and non-aflatoxigenic species (A. oryzae, A. sojae and A. tamarii). Aflatoxins are food-borne toxic secondary metabolites produced by Aspergillus species, causing hepatic carcinoma and stunting in children and are the most toxic carcinogenic mycotoxins ever identified. Despite the well-known public health problems associated with aflatoxicosis in Uganda, information about the genetic diversity of the main aflatoxin causing fungus, Aspergillus flavus in this country is still limited. Results A cross-sectional survey was therefore carried out in three main groundnut-growing agro-ecological zones (AEZs) of Uganda; West Nile farming system, Lake Kyoga basin mixed farming system and Lake Victoria basin farming system. This was to assess the genetic diversity of A. flavus and to establish the contamination rates of groundnuts with Aspergillus species at pre- and post-harvest stages. Out of the 213 A. flavus isolates identified in this study, 96 representative isolates were fingerprinted using 16 insertion/deletion microsatellite markers. Data from fingerprinting were analyzed through Neighbor Joining while polymorphism was determined using Arlequin v 3.5. The pre- and post-harvest contamination rates were; 2.5% and 50.0% (West Nile farming system), 55.0% and 35.0% (Lake Kyoga basin mixed farming system) and 32.5% and 32.5% (Lake Victoria basin farming system) respectively. The Chi-square test showed no significant differences between pre- and post-harvest contamination rates among AEZs (p = 0.199). Only 67 out of 96 isolates produced suitable allele scores for genotypic analysis. Analysis of genetic diversity showed higher variation within populations than among populations. Two major clusters (aflatoxigenic and non-aflatoxigenic isolates) were identified as colonizing groundnuts at pre- and post-harvest stages. Conclusions These findings provide a first insight on the existence of non-aflatoxigenic strains of A. flavus in Uganda. These strains are potential candidates for developing local Aspergillus bio-control agent.

scholarly journals Genetic diversity of aflatoxin-producing Aspergillus flavus isolated from selected groundnut growing agro-ecological zones of Uganda

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Amos Acur ◽  
Renée S. Arias ◽  
Steven Odongo ◽  
Samuel Tuhaise ◽  
Joseph Ssekandi ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Aspergillus Flavus ◽  
Ecological Zones ◽  
Agro Ecological Zones

Genetic Diversity of Aphid (Hemiptera: Aphididae) Species Attacking Amaranth and Nightshades in Different Agro-Ecological Zones of Kenya and Tanzania

2018 ◽  
Vol 26 (2) ◽  
pp. 407-421
Author(s):  
A.C. Kipnyargis ◽  
F.M. Khamis ◽  
E.U. Kenya ◽  
S. Ekesi ◽  
K.K.M. Fiaboe
Keyword(s):  
Genetic Diversity ◽  
Ecological Zones ◽  
Agro Ecological Zones

scholarly journals Wetland Use/Cover Changes and Local Perceptions in Uganda

2013 ◽  
Vol 2 (4) ◽  
pp. 95 ◽  
Author(s):  
Nelson Turyahabwe ◽  
David Mwesigye Tumusiime ◽  
Willy Kakuru ◽  
Bernard Barasa
Keyword(s):  
Lake Victoria ◽  
Water Levels ◽  
Livestock Grazing ◽  
Wetland Classification ◽  
Local Perceptions ◽  
Ecological Zones ◽  
And Migration ◽  
Major Factors ◽  
Agro Ecological Zones ◽  
Wetland Use

<p>With increasing population, coupled with land shortage and weather variations, wetlands in Uganda have continued to face degradation due to mainly conversion for agricultural, industrial and settlement purposes. The objective of this study was to determine the spatial and temporal wetland use/cover changes and local perceptions attributed to these changes. The study utilized three sets of ortho-rectified and cloud free Landsat TM/ETM+/MSS temporal images (30 m) of 1986, 2000 and 2011. The classification procedures were carried out using an Integrated Land and Water Information System (ILWIS) software version 3.7. A wetland classification system for Uganda developed by the National Biomass Study, 2003 was adopted to describe the wetland use/cover types. The classified images were validated in a ground truthing exercise using Global Positioning System (GPS) to improve on the classification accuracy. Key informant interviews and focus group discussions were conducted with communities adjacent to the wetlands in each of three of the ten Ugandan agro-ecological zones to determine the underlying drivers of wetland use/cover changes, while household interviews generated information on local perceptions of the changes. Significant changes were mainly observed in wetland use/cover between 1986 and 2011. Major factors responsible for these changes were subsistence farming due to intensification of growing paddy rice in Kyoga plains, an influx of migrants who accessed wetlands for daily subsistence (livestock grazing) in South western farmlands and proximity to urban centres in the Lake Victoria Crescent. In all the sampled agro-ecological zones, increased crop farming in wetlands was due to changing opportunities created by existent large markets for wetland crops. Majority (60%) of the local people perceived wetlands in their proximity to have undergone high degradation within the last 10 years, and to have declined in quantity and quality of vegetation, soil fertility and water levels. There was a noticeable variation across the sampled agro-ecological zones, with the highest proportion of local communities perceiving degradation being in Kyoga plains (76%), followed by Lake Victoria crescent (63%) and South-western farmlands (41%). Locally perceived threats to wetlands were mainly from crop growing that accounted for 33% of the frequency of mentioned threats, collection of wetland resources (30%), and prolonged floods and droughts (12%). This study confirms the importance of economic opportunities from new market outlets and migration in its various forms as key factors in land use change, especially at timescales of a couple of decades.<strong></strong></p>

L'élevage en cage à faible niveau d'intrants: vers la sécurité alimentaire et L'amélioration du niveau de vie en zones rurales au Kenya.

2020 ◽  
Author(s):  
Harrison Charo-Karisa ◽  
Jonathan M Munguti ◽  
Herwig Waidbacher ◽  
David Liti ◽  
Werner Zollitsch
Keyword(s):  
Lake Victoria ◽  
Low Cost ◽  
Farming System ◽  
Cage Culture ◽  
Lake Victoria Basin ◽  
Sécurité Alimentaire ◽  
Aquaculture Production

Abstract Recent experiences and successes, including the decline in capture fisheries and the overall increase in aquaculture production, have sparked the development of commercial cage culture in Africa. This case study focuses on tilapia cage culture in the waters of Lake Victoria in Kenya and in secondary dams in the Lake Victoria basin. It highlights the challenges and innovations that Kenyan fish farmers and fishermen have demonstrated to achieve success. In particular, the study takes into account the public's ever-growing interest in and questioning of the sustainability of this farming system in the lake, both ecologically and environmentally. This study presents how fish farmers and researchers have successfully reared caged fish with low cost feed, to produce quality seeds, and to use locally available materials for the construction and safety of cages. Cage farming can be profitable in the Lake Victoria basin if the obstacles that arise as the process develops are gradually overcome.

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