Papers by Gerald Kwikiriza
African Journal of Agricultural Research, May 9, 2019
The yield of potato, an important food security and income crop in Uganda is substantially affect... more The yield of potato, an important food security and income crop in Uganda is substantially affected by pests. A survey was carried out in south western Uganda, a major potato growing area to assess the distribution and severity of potato pests in June and July 2015. In addition, leaf miner management options such as pesticide use, yellow sticky traps and mulching were evaluated for effectiveness. Trials in leaf miner hot spots in Bukimbiri and Chahi sub-counties of Kisoro district were conducted in three seasons during 2016 to 2017. In each sub-county, two sites were selected per season and trials were established in a completely randomized design with each treatment being replicated three times. From the survey, aphids and leaf miners were the major pests with high incidences in Kabale and Kisoro districts and rarely encountered in Rukungiri and Kanungu. Use of Dudu-acelamectin reduced leaf miner damage on leaves in season 1 (2017; P=0.001) and registered significantly higher yields compared to other treatments. Yellow sticky traps trapped high leaf miner fly populations but leaf miner damage on leaves and yield were not significantly different from control and mulched plots. Judicious use of pesticides in high leaf miner populations together with yellow sticky traps can reduce leaf miner populations and damage on potato.
Gender and Women's Studies, 2019
Potato (Solanumtuberosum) is an important crop in highland areas of South Western and Eastern Uga... more Potato (Solanumtuberosum) is an important crop in highland areas of South Western and Eastern Uganda. Seed potato business is a key input for increasing potato productivity and contributes to people livelihood. Attempts to increase seed potato production and its contribution to livelihoods of men and women have not addressed a gap in seed demand and on its contributions to incomes of the farming households. Seed producers and research provides 0.15 % of the total seed potato required. This has partly been attributed to lack of involvement of men and women in seed potato production business, leading to low yields averaging 7.5 t/ha. This research aimed at finding out factors affecting involvement of men and women in seed potato business. Questionnaires, focus group and individual interviews of key informants were conducted involving men and women selected from 3 different locations. Results indicated that men are more involved in seed potato production, own more capital resources, and are mostly head household giving them an upper hand in decision making. Most men tended to engage in key activities leading to preparation for marketing. This gives them an opportunity to negotiated for market prices, sell and receive cash on behalf of their wives. Women tended to concentrate in domestic responsibilities such as feed the family. Women refrained from engaging in key activities in the seed potato business, which undermines the benefits that accrue to them.
International journal of aquaculture, 2024
Cyclopoid copepods (Thermocyclop sp.) have the nutritional attributes of an ideal diet for fish l... more Cyclopoid copepods (Thermocyclop sp.) have the nutritional attributes of an ideal diet for fish larvae. However, long-term production and availability of copepods for feeding larval fish in hatcheries remain a challenge. The present study investigated the effect of density and temperature on survival and fatty acid profiles of Thermocyclop sp. at densities: 1 000, 3 000, and 5 000 individuals/L and temperatures: 4°C, 8°C, and 12°C. A log-rank test showed a significant difference between the percentage survival of Thermocyclop sp. at 12°C and 4°C (P<0.001) and a significantly higher survival at 1 000 than at 5 000 individuals/L (P<0.001). Generally, saturated fatty acids (SFAs) were dominant compared to monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). For essential fatty acids, no significant differences were observed between storage temperatures on the 7th and 14th days of the experiment. The results demonstrated that at least a 50% survival rate is obtained when these organisms are stored at 12°C with a density of 1 000 individuals/L for 14 days, with no significant changes in fatty acid profiles. Further studies are necessary to determine the effect of increased storage conditions, perhaps with aeration, on storage time.
Research Article, 2024
Cyclopoid copepods (Thermocyclop sp.) have the nutritional attributes of an ideal diet for fish l... more Cyclopoid copepods (Thermocyclop sp.) have the nutritional attributes of an ideal diet for fish larvae. However, long-term production and availability of copepods for feeding larval fish in hatcheries remain a challenge. The present study investigated the effect of density and temperature on survival and fatty acid profiles of Thermocyclop sp. at densities: 1 000, 3 000, and 5 000 individuals/L and temperatures: 4°C, 8°C, and 12°C. A log-rank test showed a significant difference between the percentage survival of Thermocyclop sp. at 12°C and 4°C (P<0.001) and a significantly higher survival at 1 000 than at 5 000 individuals/L (P<0.001). Generally, saturated fatty acids (SFAs) were dominant compared to monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). For essential fatty acids, no significant differences were observed between storage temperatures on the 7th and 14th days of the experiment. The results demonstrated that at least a 50% survival rate is obtained when these organisms are stored at 12°C with a density of 1 000 individuals/L for 14 days, with no significant changes in fatty acid profiles. Further studies are necessary to determine the effect of increased storage conditions, perhaps with aeration, on storage time.
Fishes, Apr 20, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Despite their high abundance and species richness, tilapiines have been compromised by various fa... more Despite their high abundance and species richness, tilapiines have been compromised by various factors especially overfishing, climate change, and un-controlled fish translocations. Fish translocations have negatively impacted native tilapiine populations through competition, predation, hybridization, and introgression compromising their genetic integrity. The hybridization levels of different tilapiines in the Lake Victoria basin remains an understudied aspect relatively. The study utilized nuclear microsatellite and mitochondrial DNA (mtDNA) genetic markers to investigate hybridization signals and compare the genetic diversity of different tilapiines in Lake Victoria, Kenya, using next-generation sequencing. Low levels of hybridization from Oreochromis niloticus into other Oreochromis species were detected by Bayesian clustering analysis and principal coordinate analysis (PCoA). The results contribute to the need for conservation measures of these fish species.
El Caldero de la Escuela. Publicación de la Escuela de la Orientación Lacaniana, 2010
International Journal of Fisheries and Aquatic Studies, 2016
Long larval and fry rearing period due to unreliable live food sources are problematic in fry rea... more Long larval and fry rearing period due to unreliable live food sources are problematic in fry rearing process affecting aquaculture production in most hatcheries. As a result, this study investigated the performance of African catfish (Clarias gariepinus) fry fed on live rotifers, a mixture of rotifers and formulated diet (Ugachick feed 45%). Seven days post hatch fry of Clarias gariepinus were reared under three different treatments; A, B and C with triplicates in a complete randomized design in 40L concrete tanks. Fry in treatments A and C were exclusively fed on live rotifers and formulated feed respectively. In B, the fry were fed on mixture of live rotifers and formulated feed for 15days. At the end of the experiment, final mean total length (TL), specific growth rates (SGR) and survival rates (SR) were determined. Significantly highest (P
International Journal of Fisheries and Aquatic Studies, 2016
Proximate analysis of ingredients provides reference database of the nutritional composition of t... more Proximate analysis of ingredients provides reference database of the nutritional composition of the locally available ingredients that can be used in fish feed formulation. Proximate nutrient analysis was performed on seven locally mobilized ingredients from Uganda. The ingredients were analyzed for Moisture, Ash, Crude fat, Crude protein, Gross energy contents and matter basis using standard methods. Moisture content ranged from 8.05% in fish meal to 11.28% in chicken offal, ash content ranged from 4.21% in blood meal to 12.57% in fish meal, crude fat ranged from 1.44% in cattle blood meal to 7.66% in fish meal, crude protein ranged from 56.53% in chicken offal to 70.09% in blood meal while Gross energy ranged from 3673 Kcal/kg in fish meal to 4601 kcal/kg in chicken offal. The cost per kilogram protein ranged from Uganda shillings (Ugshs) 6.19 in chicken offal to Ugshs 7.1 in blood meal. The cost per kilogram energy varied from Ugshs 0.76 in chicken offal to Ugshs 1.38 in blood me...
Low macronutrient levels in the soil greatly affect the yield of Potato (Solanum tuberosum L.) in... more Low macronutrient levels in the soil greatly affect the yield of Potato (Solanum tuberosum L.) in Uganda. The study was undertaken to determine the effect of macronutrient combinations on yield of potato. This was done in 6 sites across south western Uganda. The 5 levels of N:P:K combinations were laid in split plot arrangement with Mode of Application (MoA) allocated to main plots and nutrient combinations allocated to the sub plots. The results indicated that basal application significantly increased potato yield. Macronutrient combinations led to increase in potato yield with application of 100:75:200 performing better on ware and in season 2. Application of 75:50:150 was good for seed production and in season one when rains are not sufficient. Season 2 was the best season in the performance of macronutrient combinations. Karengyere was the best site for the potato yield response to nutrient combinations. The results showed 100:75:200 and 75:50:150 macro nutrient combination opti...
International Journal of Fisheries and Aquatic Studies, 2016
Stocking density is among the critical factors affecting fish growth. Although cage culture is gr... more Stocking density is among the critical factors affecting fish growth. Although cage culture is gravely being promoted by the government, information regarding the impact of stocking density on fish growth performance of juveniles in cages in Uganda is limited. This study examined the growth performance of Monosex Nile tilapia (Oreochromis niloticus) juveniles at various stocking densities in cages. The fish of mean wet weight and total length of 1.1±0.1g and 1.3±0.1cm respectively were transferred from nursing ponds in aerated containers to experimental cages at three stocking densities (1000, 1250 and 1500 juveniles/m3). The fish were fed on 45% crude protein formulated diet and total length and wet weight were determined weekly for eight weeks. During each sampling event, water quality parameters (temperature, dissolved oxygen and pH) were measured at the surface and 1.5-2.0 meter depth, before, within and after cages to assess the effect of cages on the water quality in and aroun...
Journal of Development and Agricultural Economics, 2017
The study evaluated the socioeconomic viability and factors influencing profitability of apple en... more The study evaluated the socioeconomic viability and factors influencing profitability of apple enterprise under smallholder farming system in Uganda. A sample of 52 apple farming households was randomly selected in the districts of Uganda: Kabale, Kisoro, Kanungu and Rukungiri. Data were collected with the use of structured questionnaires, and analyzed using descriptive statistics, gross margin analysis and multiple regression model. The results showed that apples were planted on small scale with only 6% of land allocated to total apple enterprise in 2011. However, land allocation to apple enterprise is increasing and the enterprise currently covers 20% of farm lands. The dominant varieties among apple farmers are Golden Dorset, 56.1% and Anna, 40.9%. Men constituted 74.5% of the apple farmers, while the mean age of apple farmers was 57 years, with an average experience of over 10 years. Gross margin of apple enterprise in Kabale and Kanungu district had a positive ratio of return on investment of 1.5 and 1.7, respectively. Kisoro and Rukungiri districts had a negative ratio of return on investment of (0.9 and 0.3, respectively). Ordinary least squares (OLS) results indicated that the gender of the respondent, family size, access to credit, influence of birds, type of apple variety, number of apple trees planted, amount of labor used and quantity of inorganic fertilizers applied were significant determinants of net income in apple production. There is need to reduce the labor costs in apple establishment and management, promote strategies that encourage the youth to participate in apple farming. Research has to come up with an effective but affordable remedy against the negative influence of birds in apple production. Farmers need to be linked to financial providers for credit access at low interest rate in order to facilitate routine apple management practices.
Fisheries and Aquaculture Journal, 2017
The availability of O. niloticus fingerlings remains a problem in South Western Highland Agro-Eco... more The availability of O. niloticus fingerlings remains a problem in South Western Highland Agro-Ecological Zones. Most fish farmers produce only small sized fish probably because of inbreeding in Uganda. Brood stocks of Nile tilapia, Oreochromis niloticus L. were collected from Lakes Victoria, Kyoga and Kayumbu, a minor lake in SWHAEZ. The brood-stock were conditioned and bred. Fingerlings of F1 generation of each strain were fed diet containing 35% Crude Protein for 90 days. The results showed that Victoria strain growth performance was better compared to other tilapia strains in growth performance. Survival rate was not significantly different among Nile tilapia strains. Crude protein contents in fish body was higher in Victoria (69.30%) followed by Kayumbu strains (68.125%) with Kyoga having the least crude protein content (64.5%). Fish body of Kayumbu strains contained higher values of crude fat (11.70%) followed by Victoria strain (9.90%) while Kyoga strain had the least crude lipid (8.50%). The Victoria strain (47.8 g feed/fish) had significantly higher feed intake and PER than all the other strains. Kyoga and Kayumbu strains were comparable in terms of feed intake. However, the Kayumbu strain had significantly the least PER (2.46). The lowest FCR value was obtained in Kayumbu strain (1.67), while the higher ones were obtained in Kyoga and Victoria strains 1.82 and 1.78, respectively). The poor performance of kayumbu strain was probably due to in breeding and other environmental factors like temperatures. Therefore, exploitation of the genetic variation within the different native wild strains through selective breeding can help to improve growth performance of the Kayumbu strain in South Western Highland Agro-Ecological Zones (SWHAEZ).
Agriculture, Forestry and Fisheries, 2018
The study was conducted to identify the constraints and potential opportunities of cage fish farm... more The study was conducted to identify the constraints and potential opportunities of cage fish farming in South Western Highland Agro-Ecological Zone (SWHAEZ). 82 questionnaires were administered to six respondent groups (current cage fish farmers, potential adopters of cage aquaculture, farmers who have abandoned cage aquaculture, regional and district fisheries officers, and financial institutions) to obtain insight into the challenges in cage fish farming as well as opportunities that can be exploited to promote cage fish farming. People in relevant government institutions were also interviewed. Primary results show that lack of funds and lack of government extension services are key challenges in cage fish farming. Lack of funds incapacitates farmers' failure to get aquaculture inputs like feed. It also accounted for the inability of potential adopters and farmers who have abandoned cage aquaculture to start or continue cage aquaculture respectively. Major opportunities identified include; availability of the market for the fish, willingness of the financial institutions to offer loans at a cheaper interest rate, availability of the extension services at the sub-county level. Our preliminary recommendations is that the government can also provide subsidies to most expensive inputs like feeds, seine-net, water testing kits and construction costs for aquaculture. There is need to empower and build capacity for the extension workers through improved good management practices like feed and feeding and record keeping.
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Papers by Gerald Kwikiriza