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ItemStarch profiles and their biothysnthetic markers in selected east African highland cooking bananas(Makerere University, 2025)The East African Highland Cooking bananas (EAHCBs), a staple food and a key source of carbohydrates for millions in the Great Lakes region, are primarily consumed as cooked products. Despite their nutritional and economic significance, limited scientific attention has been given to understanding the diversity of starch properties in these cultivars and their underlying genetic basis. This study aimed to profile the starch physicochemical characteristics and identify associated genetic markers in selected EAHB cultivars to support value-added utilization of this banana and its targeted breeding for commercial industrial applications. A total of 11 banana cultivar starches were analyzed for starch content, amylose-to-amylopectin ratio, granule morphology, solubility indices and swelling power, pasting properties and molecular structure and chemical composition using standard biochemical and AOAC analysis techniques. Concurrently, molecular profiling was conducted using real time PCR for differential expression levels and Sanger sequencing to identify genetic markers linked to observed starch traits. Results revealed significant variability in the physicochemical and functional characteristics among the cultivars in key starch parameters, with certain varieties showing traits desirable for industrial or nutritional applications when compared to common commercial starches (native and modified). Marker-trait association studies identified specific gene potentially controlling starch quality attributes. PLSR analysis revealed that GBSS1, MaSSIII-1, and SDE each play distinct but complementary roles in regulating starch properties in East African Highland Cooking Bananas (EAHCB). It further pinpointed specific starch biosynthesis genes that influence specific starch parameters. For example, GBSS1 was strongly associated with viscosity-related traits, particularly pasting temperature. MaSSIII-1, by contrast, with starch yield, starch content, Particle size and mechanical strength consistent with its role in synthesizing branched amylopectin chains that form semi- crystalline regions crucial for thermal stability and gelatinization behavior. SDE while has a less dominant but still relevant role in starch functionality. It showed moderate influence on swelling power and solubility significantly affected amylose content, amylose–amylopectin ratios, and suggesting a regulatory role in fine-tuning starch granule structure and organization through the activity of debranching enzymes. These results underscore the multi-gene control of starch functionality in bananas, where GBSS1 governs quantity and structure, MaSSIII-1 modulates thermal properties, and SDE influences granule architecture thereby providing important insights for improving starch quality through targeted breeding. These findings provide foundational knowledge for the development of improved EAHCB cultivars tailored for both food and non- food applications through marker-assisted selection. The study contributes to bridging the gap between traditional crop use and modern genetic improvement approaches, enhancing the value chain of cooking bananas in the region. Future work should validate the identified markers in larger populations and explore their role in starch biosynthesis pathways.
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ItemEvaluation of Light Emitting Eiode (LED) on the in-vitro performance of selected east African highland banana cultivars(Makerere University, 2025)Tissue culture has been identified as a technology that has the potential to provide large quantities of clean planting materials all year round. Up to 500 banana plantlets can be obtained from one sucker in a year. However, the current cost of a tissue culture-derived plantlet is $0.9 which is too high for a smallholder farmer. Part of the cost is attributed to the energy used for lighting and cooling taking a reasonable percentage of the production costs. In-vitro plant propagation uses artificial growth factors to maintain asepsis in the laboratory setting among others and light. Conventional florescent lights are used in growth rooms to provide lighting to the cultures offering general spectra for growth and 30% is converted into energy for the plants to utilize while 70% is converted into heat. This generated heat that can only be regulated by running air conditioners to be able to attain the optimum temperature required for banana culture growth. The present study aimed to investigate the optimum light intensity of the new combinations of LED light as compared to the white light spectrum for banana morphogenesis in terms of multiplication rates, chlorophyll content, and survival rates at the post-flask handling stage. Three replicates of meristematic tissues used as cultures were maintained in a growth room at 27±2°C, under LED light with spectral combinations of ultraviolet, blue, green, red and far red in the following percentages A (0,14,15,54,17); B (0,12,19,61,8); C (1,21,38,36,6) and D as control was under white fluorescent light. Results show no significant effect in terms of buds’ multiplication across treatments but treatment B for specific genotype Kisansa, indicated higher rates of buds. Shoots showed a higher multiplication rate at treatment C with genotype Nabio 808 than others. Roots development showed more long roots on treatment A on genotype Kisansa while short roots where indicated on treatment A on genotype Bogoya. Chlorophyll content production varied among treatments but the highest was attained at light treatment C on genotype Kisansa, followed by light treatment B on genotype Mpologoma. At the post-flask handling stage, all three treatments showed 98.5 % survival in the acclimatization and hardening phase compared to white light. Therefore, use of LEDs for micro-propagation of the EAH banana will be adopted due to its superiority compared to conventional fluorescent white light for spectral specificity, long operational duration and reductions in energy investment although significant differences were not realised at some growth stages.
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ItemAssessment of the optimal gillnet mesh size for harvesting Brycinus nurse (Rüppell, 1832) in Lake Albert, Uganda(Makerere University, 2025)Brycinus nurse (locally known as Ragooge) within the Albertine region, is one of the commercially important fish species in Lake Albert. The species is harvested using undersize mesh gillnets that are prohibited under the Ugandan fishing regulations, raising concerns among fisheries stakeholders. These concerns are further exacerbated by the absence of scientific information on key life history traits such as sizes at maturity and optimal mesh size for harvesting this species in Lake Albert, hindering formulation of sustainable management strategies for the species. This study evaluated gillnet mesh size selectivity for B. nurse in the Ugandan waters of Lake Albert and identified the optimal mesh size for sustainable harvesting of the species to help develop species-specific management regulations. The study was conducted at four sites (Wanseko, Butiaba, Kaiso, and Ntoroko), covering both inshore and deep open water habitats. Fish sampling involved a range of gillnet mesh sizes from 25.4 mm (one inch) to 101.6 mm (four inches, which is the minimum legal mesh size for Lake Albert in Uganda). Life histories traits, including size structure, length-weight relationships, relative condition, and size at first maturity, were evaluated to assess status of the species. The length (fork length – FL) at 50% maturity of B. nurse in Lake Albert was estimated at 92.1 mm for females and 84.8 mm for males. The smaller gillnets (25.4 mm – 50.8 mm) caught a high proportion of both the target species and immature stages of various large-bodied species, raising concerns about stock sustainability. Gear selectivity analysis showed that 38.1 mm mesh gillnets were effective in catching mature B. nurse above the size at 50% maturity but also caught a wide variety of by-catch species. Based on these results, the 38.1 mm gillnet mesh size is recommended as the most effective and sustainable gear for harvesting B. nurse.
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ItemDiversity, abundance and population structure of tree species in Mabira Central Forest Reserve and adjacent fragments(Makerere University, 2025)Mabira Central Forest Reserve (CFR) and its adjacent fragments face significant anthropogenic and ecological threats, including resource extraction and changes in land use. This has led to degradation and fluctuations in forest size, biodiversity loss, an increase in invasive species, and ecological changes. Understanding the diversity of tree species and the effects of fragmentation in Mabira CFR fragments is crucial for developing informed conservation strategies, restoring habitats, promoting connectivity, and balancing conservation efforts with development to maintain biodiversity. The study aimed to assess the influence of fragmentation on tree species diversity and abundance in Mabira CFR and adjacent forest fragments of Nandagi and Namukupa CFRs. The study specifically sought to compare: a) tree species diversity in Mabira CFR and its adjacent forest fragments, and b) tree density in Mabira CFR and its adjacent fragments. Tree species diversity, community similarity, composition, community structure, and population structure were investigated. Systematic sampling was employed, and along each transect, 30 m x 30 m quadrats were established alternately. Per quadrat, trees’ DBH were recorded under the different size classes, and the total number of trees per species in a quadrat was counted. The tree species were identified at the Makerere University Herbarium. The results revealed a total of 95 tree species, belonging to 66 genera and 37 families. Eighty-six species were found in Mabira, 67 in Nandagi, and 37 in Namukupa. The evaluation of tree density across different size classes revealed that Nandagi and Namukupa exhibited an approximation of an inverse J-curve, indicative of ongoing regeneration and a relatively healthy community structure. Mabira CFR, though the most intact forest, had a less stable and unhealthy structure with inconsistent densities across size classes. Mabira CFR had the highest tree species diversity (H’ = 2.58), followed by Nandagi (H’ = 2.16) and Namukupa (H’ = 1.01), and these differed significantly (p = 1.492e-10, n = 3). The most important tree species based on their Importance Value Index values were Trilepisium madagascariense DC. In Mabira CFR, Cedrela odorata L. in Nandagi CFR, and Broussonetia papyrifera (L.) L'Hér. ex Vent in Namukupa CFR. Namukupa CFR had the highest median stem density among the three study sites (1100 trees/ha), followed by Nandagi CFR (1033.3 trees/ha) and Mabira CFR (944.4 trees/ha). However, these differences in stem density were not statistically significant (p = 0.1185, n = 3). In conclusion, the study revealed that forest fragmentation negatively influences tree species diversity, and that while tree density may increase in small fragments, it does not reflect the ecological health of the forests. Mabira was a more advanced and stable mature forest community than the other two fragments of Namukupa and Nandagi. The dominance of Broussonetia papyrifera - an invasive species in Namukupa shows a shift in community structure, poses a significant threat to native species composition, and underscores the urgent need for management interventions to prevent the degradation of ecosystem integrity. It is recommended that the National Forestry Authority (NFA) explore opportunities to reduce fragmentation and isolation of forest fragments, such as agroforestry on intervening private lands and the establishment of buffer zones around forest fragments. Future studies should assess the spatial distribution and population structures of threatened tree species or those with low IVIs to inform the development of management and restoration strategies. Sites with low stem density should be enriched with indigenous, fast-growing pioneer species to close the canopy gaps and foster forest recovery and advancement to a more primary forest community. Natural regeneration by creating protected zones within the CFRs should be encouraged to allow seedlings to grow into mature stems without interference from human disturbances.
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ItemFourier transform infrared spectroscopy as a rapid method for the detection of adulteration in groundnut powder and paste retailed in Kampala(Makerere University, 2025)Anecdotal evidence suggests that groundnut products in Uganda are frequently adulterated with maize, cassava, millet, bean, and jackfruit seed powders. Traditional detection methods currently in use such as HPLC, GC-MS, and MALDI-TOF, are costly and time-consuming, necessitating rapid, cost-effective, and non-destructive alternatives. This study aimed to evaluate the applicability of Fourier Transform Infrared (FTIR) spectroscopy as a fast and cost-effective method for detecting adulteration in groundnut products retailed in Kampala, Uganda. Methods: A cross-sectional study design involving 100 packaged and unpackaged retail samples purchased from 5 divisions of Kampala, alongside authentic groundnuts, 5 adulterants (maize flour, cassava flour, millet flour, bean seed powder, and jackfruit seed powder), and 50 deliberately adulterated groundnut samples. Spectral data (4000–400 cm⁻¹) were acquired using Shimadzu FTIR-8400S. PCA was done using SIMCA 18 to classify the adulterants in the samples. Authentic groundnuts showed distinct lipid peaks (2923, 2855, 1743 cm⁻¹), while adulterants exhibited carbohydrate (1000, 1149 cm⁻¹) and fiber (1418 cm⁻¹) markers. These spectral features helped differentiate authentic groundnut samples from those that were adulterated. PCA effectively separated clusters, with PC1 (65.4%) and PC2 (15.7%) accounting for 81.1% of the cumulative variance. Of the 100 market samples, 25 % were classified as authentic, 45 % were adulterated (cassava flour 13 %, millet flour 12 %, bean 9 %, jackfruit seed 7 %, maize 4 %), and 30 % remained unclassified (likely complex or unknown adulterant mixtures). Packaged samples showed very low adulteration (2 %), whereas unpackaged samples reached 43 %. Powder forms (40 %) were more adulterated than paste (5 %). Fourier Transform Infrared coupled with PCA, offers a nondestructive, rapid, and non-targeted method for groundnut adulteration detection in Kampala. Its integration into regulatory frameworks could enhance food safety monitoring, ensuring the authenticity and quality of groundnut products in local markets. Keywords: Food fraud, FTIR spectroscopy, Chemometrics, Principal Component Analysis, Groundnut adulteration, Kampala.