Browsing by Author "Kyamanywa, Samuel"
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Item Assessment of Municipal Organic Solid Waste, as a Potential Feedstock for Briquette Production in Kampala, Uganda(Uganda. Journal of Sustainable Bioenergy Systems, 2020) Abondio, Richard B.; Komakech, Allan J.; Kambugu, Robert K.; Kiggundu, Nicholas; Wanyama, Joshua; Zziwa, Ahamada; Kyamanywa, SamuelThe current shortage of energy resources coupled with environmental degradation problems resulting from deforestation in Uganda has contributed to increased demand for renewable energy resources including municipal organic solid waste and agricultural residues. However, organic waste from Municipal Solid Waste (MSW) may contain contaminants that are harmful to public health and the environment. This study determined the heavy metal concentration in MSW in Kampala City, Uganda. Also, the physicochemical properties of briquettes produced from the MSW were compared with charcoal. The waste samples were collected from residential, institutional and market areas over a period of two weeks. They were then analyzed for the presence of heavy metals. Briquettes were made from the bio-waste and were subjected to calorific and proximate analysis. Results indicated that the mean concentrations of Cd, Cr, Cu, Fe, and Pb were 1.25 mg/kg, 2.04 mg/kg, 38.2 mg/kg, 3.97 mg/kg and 1.99 mg/kg respectively while Hg was not detected. The calorific values of briquettes ranged from 8.9 to 15.3 MJ/kg and were lower than those of charcoal. Heavy metal concentrations in bio-waste collected were below the permissible acceptable limits. These findings indicate that the sampled MSW does not pose a health hazard arising from the presence of such heavy metals and therefore could be a safe source of renewable energyItem Can Occurrence and Distribution of Ground Beetles (Carabidae) Be Influenced by the Coffee Farming System in the Mount Elgon Region of Uganda?(Neotropical Entomology, 2021) Raphael Ijala, Anthony; Kyamanywa, Samuel; Cherukut, Scola; Sebatta, Christopher; Hilger, Thomas; Karungi, JeninahThe Mount Elgon region of Uganda has coffee farmlands distributed along the slopes of the mountain, in a mosaic of differing crop combinations, and semi-natural vegetation. Thus, there are parcels of varying microclimate that create disparities in occurrence of key insect functional groups. The study quantified the occurrence of Carabidae in 72 coffee farmlands categorized by altitude: low (1400–1499 m.a.s.l), mid (1500–1679 m.a.s.l), and high (1680–2100 m.a.s.l); and farming system: coffee monocrop, coffee+annual crops, coffee+banana, and coffee+banana+shade trees. The results revealed highly significant effects of altitude, farming systems, and the interaction of the two on occurrence of three Carabidae genera (Anisodactylus, Chlaenius, and Harpalus.). The abundance of Harpalus spp. was higher at lower altitudes in coffee monocropped farming systems; Anisodactylus spp. were more abundant at higher altitudes in coffee+annual crop systems; and Chlaenius spp. were highest in the coffee+banana+shade tree system at mid altitudes. The belowground microclimate parameters of soil moisture, pH, EC; and the aboveground diversity of semi-natural vegetation explained some of the differences in occurrence of the different Carabidae genera. This distinctiveness in preference of different genera in the same family hinders collective recommendations but looks to a more pragmatic strategy in nurturing diversity on a holistic scale.Item Contrasting effects of shade level and altitude on two important coffee pests(Journal of Pest Science, 2015) Jonsson, Mattias; Ijala, Anthony Raphael; Ekbom, Barbara; Kyamanywa, Samuel; Jeninah, KarungiThe diversity and abundance of natural enemies of insect pests is often higher in agroforestry plantations than in sun-exposed monocultures, and it is often assumed that this will lead to improved pest suppression. The effect that incorporating trees in cropping systems will have on pest populations, however, also depends on the habitat requirements of the pests themselves. In Eastern Uganda, we studied how shade level (full [50 trees per acre, moderate 21–50 trees per acre, and low 0–20 trees per acre) and altitude (high 1,717–1,840 m.a.s.l. and low 1,511–1,605 m.a.s.l.) influenced the abundance of the white stem borer Monochamus leuconotus and the coffee berry borer Hypothenemus hampei. We found that the effect of shade trees differed between the two pest species. The coffee berry borer was more common on sun-exposed plantations, whereas the white stem borer was more common in shaded plantations. Furthermore, the effect of shade level on the white stem borer depended on altitude, with the differences between shade levels being most pronounced in plantations at low altitudes. This implies that the impact of agroforestry on pest regulation both under current conditions and in a global warming scenario will be highly context dependent; it will depend on the identity of the most important pests in the area, and on environmental factors such as altitude.Item Factors Influencing Genomic Prediction Accuracies of Tropical Maize Resistance to Fall Armyworm and Weevils(Plants, 2021) Badji, Arfang; Machida, Lewis; Kwemoi, Daniel Bomet; Kumi, Frank; Okii, Dennis; Mwila, Natasha; Agbahoungba, Symphorien; Ibanda, Angele; Bararyenya, Astere; Ndapewa Nghituwamhata, Selma; Odong, Thomas; Wasswa, Peter; Otim, Michael; Ochwo-Ssemakula, Mildred; Talwana, Herbert; Asea, Godfrey; Kyamanywa, Samuel; Rubaihayo, PatrickGenomic selection (GS) can accelerate variety improvement when training set (TS) size and its relationship with the breeding set (BS) are optimized for prediction accuracies (PAs) of genomic prediction (GP) models. Sixteen GP algorithms were run on phenotypic best linear unbiased predictors (BLUPs) and estimators (BLUEs) of resistance to both fall armyworm (FAW) and maize weevil (MW) in a tropical maize panel. For MW resistance, 37% of the panel was the TS, and the BS was the remainder, whilst for FAW, random-based training sets (RBTS) and pedigree-based training sets (PBTSs) were designed. PAs achieved with BLUPs varied from 0.66 to 0.82 for MW-resistance traits, and for FAW resistance, 0.694 to 0.714 for RBTS of 37%, and 0.843 to 0.844 for RBTS of 85%, and these were at least two-fold those from BLUEs. For PBTS, FAWresistance PAs were generally higher than those for RBTS, except for one dataset. GP models generally showed similar PAs across individual traits whilst the TS designation was determinant, since a positive correlation (R = 0.92***) between TS size and PAs was observed for RBTS, and for the PBTS, it was negative (R = 0.44**). This study pioneered the use of GS for maize resistance to insect pests in sub-Saharan Africa.Item Identification of candidate genes associated with resistance to bruchid (Callosobruchus maculatus) in cowpea(Plant Breeding, 2019) Miesho, Belay; Hailay, Mehari; Msiska, Ulemu; Bruno, Awio; Malinga, Geoffrey M.; Obia Ongom, Patrick; Edema, Richard; Gibson, Paul; Rubaihayo, Patrick; Kyamanywa, SamuelCowpea is an important legume crop widely grown in sub‐Saharan Africa for food and feed. However, it is largely challenged by bruchid, a serious storage pest resulting in losses in quantity and quality of grains. Therefore, this research was designed to contribute to the breeding of cowpea resistance to bruchid through the identification of candidate genes associated with resistance to bruchid. A total of 217 mini‐core cowpea accessions were genotyped and phenotyped for their reactions to bruchid. To determine the genomic regions linked with bruchid resistance, 41,948 polymorphic SNP markers were used. Genome‐wide association study identified 11 SNPs linked to the average number of eggs, holes, insect emergence and development period and Dobie susceptibility index. Gene search via Phytozome identified six candidate genes (Vigun08g132300, Vigun08g158000, Vigun06g053700, Vigun02g131000, Vigun01g234900 and Vigun01g201900) associated with the resistance traits. These candidate genes could be incorporated into the farmers preferred but susceptible cowpea varieties to bruchid. The SNP markers associated with the resistance traits can be used in marker‐assisted breeding for accurate and rapid screening of cowpea resistant genotypes to bruchid.Item Influence of wetland borders on prevalence of fall armyworm and wasps in maize-soybean cropping system in Eastern Uganda(International Journal of Pest Management, 2021) Ojuu, David; Kyamanywa, Samuel; Odong Lapaka, ThomasThe non-crop habitats within agro-ecosystems are important resources for ecological and biological insect pest management. Diversified cropping systems are known to influence pest populations, however, how neighboring habitats affect pest population dynamics is not clear. This study focused on understanding the influence of wetland borders on Fall Armyworm (FAW) and wasps prevalence in a maize-soybean intercrop system in Eastern Uganda. FAW and wasps population estimates were carried out in twelve farmers’ fields stratified within 0–300 and 500–1100 meters from the wetland borderline. Data were collected biweekly from emergence until post flower growth of the crops. Results showed the prevalence of FAW was significantly higher on maize-soybean fields 500–1100 meters compared to those within 0 to 300m from the wetland borders. While the prevalence of wasps was significantly higher in the crops at 82–219 meters from wetland borderline. It is concluded that wetland borders play a crucial role in negatively affecting crop pest populations while positively influencing natural enemy populations and these effects are influenced by distance of crop fields from the wetland border.Item IPM Vegetable Systems in Uganda(Springer, Dordrecht., 2016) Karungi, Jeninah; Erbaugh, J. Mark; Ssonko, Robinah N.; Bonabana- Wabbi, Jackline; Miller, Sally A.; Kyamanywa, SamuelSmallholder famers in Sub-Saharan Africa (SSA) have been encouraged to produce horticultural crops as an agricultural and rural development strategy to enhance incomes and improve household nutrition. In Uganda, intensifi ed production of marketed vegetable crops has led to changing agricultural practices, including crop and input-intensifi cation, a changing set of pests, and increased use and reliance on synthetic pesticides to manage these pests. Beginning in 2002, the IPM CRSP team in Uganda implemented a participatory IPM program with smallholder farmers to develop and disseminate alternative pest management strategies for managing priority pests and reducing pesticide usage on tomato. The major pest constraints addressed were late blight, bacterial wilt, viruses, bollworm, aphids, thrips and white fl ies. Baseline farmer surveys indicated that farmers were spraying a variety of pesticides 12–24 times per growing season. The component technologies developed into a package and disseminated to farmers included a bacteria wilt resistant tomato variety MT56, mulching, staking, and a minimum spray schedule of 3–4 pesticide sprays per season. Impact assessments indicated that yields were 40 % higher when the package was used and reduced production costs (by reducing the number of sprays) that led to higher net revenues for IPM-practicing tomato farmers. Use of MT56 and mulching led to a 21 % reduction in production costs and led to an internal rate of return of 250 % if adopted. Use of tomato variety MT56 reduced production cost by 21 % with a Benefi t: Cost ratio of 770. Other IPM technologies developed included grafting using bacterial wilt resistant rootstocks; seedling production using low tunnel systems for pest/vector exclusion; and good nursery management practices.Item Maize Combined Insect Resistance Genomic Regions and Their Co-localization With Cell Wall Constituents Revealed by Tissue-Specific QTL Meta-Analyses(Plant Science, 2018) Badji, Arfang; Otim, Michael; Machida, Lewis; Odong, Thomas; Bomet Kwemoi, Daniel; Okii, Dennis; Agbahoungba, Symphorien; Mwila, Natasha; Kumi, Frank; Ibanda, Angele; Mugo, Stephen; Kyamanywa, Samuel; Rubaihayo, PatrickCombinatorial insect attacks on maize leaves, stems, and kernels cause significant yield losses and mycotoxin contaminations. Several small effect quantitative trait loci (QTL) control maize resistance to stem borers and storage pests and are correlated withsecondary metabolites. However, efficient use of QTL in molecular breeding requires a synthesis of the available resistance information. In this study, separate meta-analyses of QTL of maize response to stem borers and storage pests feeding on leaves, stems, and kernels along with maize cell wall constituents discovered in these tissues generated 24 leaf (LIR), 42 stem (SIR), and 20 kernel (KIR) insect resistance meta-QTL (MQTL) of a diverse genetic and geographical background. Most of these MQTL involved resistance to several insect species, therefore, generating a significant interest for multiple-insect resistance breeding. Some of the LIR MQTL such as LIR4, 17, and 22 involve resistance to European corn borer, sugarcane borer, and southwestern corn borer.Item New sources of cowpea genotype resistance to cowpea bruchid Callosobruchus maculatus (F.) in Uganda(International Journal of Agronomy and Agricultural Research, 2018) Belay Miesho, Weldekidan; Gebremedhin, Hailay Mehari; Msiska, Ulemu Mercy; Mohammed, Khalid Elsiddig; Malinga, Geoffrey Maxwell; Sadik, Kassim; Lapaka Odong, Thomas; Rubaihayo, Patrick; Kyamanywa, SamuelCowpea bruchid Callosobruchus maculatus (F.) is a major constraint to cowpea production throughout subsaharan Africa. The identification of sources of C. maculatus resistance and their incorporation into breeding programs would be a beneficial strategy to combat the devastation caused by the bruchid in stored cowpea. We evaluated 145 cowpea genotypes from Uganda and introductions from Kenya and Nigeria for resistance to bruchids. The mean number of eggs and number of holes, percentage pest tolerance, percentage weight loss, bruchid developmental period, bruchid growth and Dobie susceptibility index were significantly different among the 145 genotypes. Based on Dobie susceptibility index value, there were 18 resistant, 114 moderately resistant and 13 susceptible genotypes. Dobie’s susceptibility index correlated negatively with insect development period and percentage pest tolerance, and positively with number of eggs, growth index, number of holes and weight loss. The study identified new sources of cowpea from the studied genotypes that could be used by cowpea breeders to develop cultivars with relatively high resistance to cowpea bruchid. However, further investigations and identifcation of biochemicals that are responsible for cowpea seed resistance to bruchid are recommended.Item Parasitism of Hypothenemus hampei (Coleoptera: Scolytidae) in different farming systems and altitudes of Mount Elgon, Uganda(Journal of Applied Entomology, 2019) Raphael Ijala, Anthony; Kyamanywa, Samuel; Cherukut, Scola; Sebatta, Christopher; Karungi, JeninahAltitude and farming system play a vital role in modifying the niche for arthropods, by directly influencing microclimatic conditions, the quality and quantity of vegetative cover, which act variably on the behaviour of the pests, and their natural enemies. The objective of the study was to determine their effect on the abundance and parasitism of the Coffee berry borer (Hypothenemus hampei) in the Mount Elgon region. Altitude was categorized as: low (1,400–1,499 m.a.s.l); mid (1,500‐1,679 m.a.s.l); and high (1,680–2,100 m.a.s.l), and farming system was categorized as: Coffee monocrop; Coffee + annual; Coffee + banana; and Coffee + banana + shade trees. For each altitudinal range, each farming system was represented three times. The study was in two districts of the Mt. Elgon, covering a total of 72 Arabica Coffee study sites. The work involved field pest infestation inventories, followed by laboratory rearing for the abundance and parasitism studies. The results revealed highly significant interactions between altitude and farming system in influencing the abundance of the pest and its four parasitoids: Phymastichus coffea, Cephalonomia stephanoderis, Prorops nasuta and Heterospilus coffeicola. C. stephanoderis was highest in the mid‐altitudes within Coffee + banana+shade tree system; P. nasuta was highest at high altitude within Coffee + banana system; P. coffea was most abundant at mid‐altitude within Coffee + banana system, whereas H. coffeicola was highest at high altitude within the Coffee + annual cropping system. H. hampei counts were highest at low altitudes, especially in the Coffee + annual system. Some of these trends can be explained by the condition of the microclimate in the Coffee fields. There was a negative relationship between temperature and abundance of all the four parasitoids. Only C. stephanoderis had a relationship (+) with semi‐natural vegetation species counts. And only H. coffeicola had a relationship (+) with light intensity. These contrasted with H. hampei, which was positively related to temperature and negatively to light intensity.