Browsing by Author "Lejju, Julius B."

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    Alpine grassland palaeoecology of the Virunga Volcanoes, East Africa: A new phytolith record from Mt. Muhavura
    (Quaternary International, 2017) Murungi, May L.; McGlynn, Gayle; Lejju, Julius B.
    This study presents a first attempt at using phytoliths from a high-altitude crater lake as a palaeoecological tool at a tropical montane site. Mt. Muhavura (4127 m asl) at the border of Uganda and Rwanda is part of the Virunga volcanoes located in the Albertine Rift, one of the most biodiverse areas in Africa. To investigate the potential of phytoliths to record grassland history in an Afroalpine environment, a unique and little studied ecosystem, we analysed the phytolith content of 37 sediment samples from a 159 cm sediment core from the crater lake at the summit of Mt. Muhavura representing the last ca. 2400 years BP. Ten plant species from the Alpine belt were also analysed for their main phytolith morphotypes. Phytoliths from the sediments were grouped into 12 main categories and the most frequently occurring individual morphotypes were bilobate (33%), oblong (16%), elongate (17%) and globular psilate (13%). The phytolith assemblage consists predominantly of phytoliths characteristic of grasses (70%). A literal interpretation of the results would be that Panicoideae grasses (mainly C4) that are characteristic of warm and wet climate and C3 Pooideae subfamily grasses characteristic of cold climate/ high altitude have co-existed throughout the late Holocene in this belt. As only C3 cold climate grass subfamilies are known to occur at this altitude today, the abundance of short cell phytoliths (bilobates) typical of Panicoideae grasses in the lake sediments at this altitude presents a new perspective to the phytolith discussion. The C3 Pooideae grasses analysed did not produce bilobates. In this study, the phytolith index, Ic that is used as a proxy of past grass subfamily dominance is not representative of the taxonomic significance for which it is known. This study suggests that caution needs to be taken when using bilobate morphotypes and the Ic as indicators of grass subfamily dominance at high altitude on East African mountains as the bilobates may not be taxonomically representative of the grasses for which they are typically known. This highlights the inherent problem of phytolith redundancy even at an altitude where C3/C4 grass distribution is better delineated.
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    Exploring the genetic diversity of jackfruit (Artocarpus heterophyllus Lam.) grown in Uganda based on SSR markers
    (Genetic Resources and Crop Evolution, 2020) Nakintu, Justine; Albrecht, Christian; Muller, Christina M.; Kagoro-Rugunda, Grace; Andama, Morgan; Olet, Eunice A.; Lejju, Julius B.; Gemeinholzer, Birgit
    Artocarpus heterophyllus Lam. is an economically important tree crop that is widely cultivated inUganda for its fruit. Despite its economic importance, little is known about the genetic diversity of jackfruit in the country. This puts the crop’s genetic resource at risk as farmers selectively grow varieties based on market demand. The study analyzed the genetic diversity of A. heterophyllus trees from 12 districts belonging to three agro-ecological zones and three political regions of Uganda. Ten SSR loci were used to assess the genetic relationship among 200 trees, 197 from Uganda and 3 out-group individuals. All SSR loci were polymorphic with an average of 10.9 alleles per locus. STRUCTURE analysis proposed two genetic clusters: Cluster 1 was composed of samples from Eastern and neighboring Central districts, and Cluster 2 which constituted outgroups and samples from Western and neighboring Central districts. Results of STRUCTURE analysis were confirmed by PCoA. Mbarara District exhibited the highest genetic diversity (He = 0.79, I = 1.71), while Kamuli (He = 0.61, I = 1.08 and Pallisa (He = 0.59, I = 1.12) displayed the lowest genetic diversity despite high abundances of jackfruit trees. Molecular variation was higher within populations than among populations. Moderate and significant genetic differentiation was registered among geographical zones, while varietal differences displayed little insignificant genetic differentiation. Soft and white pulped varieties, considered inferior on the market, harbored private alleles which may be genetically valuable resources. Therefore, sustainable utilization and conservation efforts of the jackfruit genetic resource should consider preserving inferior varieties for future crop improvement.
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    Jigger Flea (Tunga penetrans) Infestations and Use of Soil-Cow Dung-Ash Mixture as a Flea Control Method in Eastern Uganda
    (International Journal of Agricultural and Biosystems Engineering, 2018) Amatre, Gerald; Lejju, Julius B.; Andama, Morgan
    Despite several interventions, jigger flea infestations continue to be reported in the Busoga sub-region in Eastern Uganda. The purpose of this study was to identify factors that expose the indigenous people to jigger flea infestations and evaluate the effectiveness of any indigenous materials used in flea control by the affected communities. Flea compositions in residences were described, factors associated with flea infestation and indigenous materials used in flea control were evaluated. Field surveys were conducted in the affected communities after obtaining preliminary information on jigger infestation from the offices of the District Health Inspectors to identify the affected villages and households.Informed consent was then sought from the local authorities and household heads to conduct the study. Focus group discussions were conducted with key district informants, namely, the District Health Inspectors, District Entomologists and representatives from the District Health Office. A GPS coordinate was taken at central point at every household enrolled. Fleas were trapped inside residences using Kilonzo traps. A Kilonzo Trap comprised a shallow pan, about three centimetres deep, filled to the brim with water. The edges of the pan were smeared with Vaseline to prevent fleas from crawling out. Traps were placed in the evening and checked every morning the following day. The trapped fleas were collected in labelled vials filled with 70% aqueous ethanol and taken to the laboratory for identification. Socioeconomic and environmental data were collected. The results indicate that the commonest flea trapped in the residences was the cat flea (Ctenocephalides felis) (50%), followed by Jigger flea (Tunga penetrans) (46%) and rat flea (Xenopsylla Cheopis) (4%), respectively. The average size of residences was seven squire metres with a mean of six occupants. The residences were generally untidy; with loose dusty floors and the brick walls were not plastered. The majority of the jigger affected households were headed by peasants (86.7%) and artisans (13.3%). The household heads mainly stopped at primary school level (80%) and few at secondary school level (20%). The jigger affected households were mainly headed by peasants of low socioeconomic status. The affected community members use soil-cow dung-ash mixture to smear floors of residences as the only measure to control fleas. This method was found to be ineffective in controlling the insects. The study recommends that home improvement campaigns be continued in the affected communities to improve sanitation and hygiene in residences as one of the interventions to combat flea infestations. Other cheap, available and effective means should be identified to curb jigger flea infestations.
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    Potential of Fermentation in Detoxifying Toxic Cassava Root Tubers
    (Journal of Agricultural Science and Technology, 2012) Andama, Morgan; Lejju, Julius B.
    Quantitative determination of hydrogen cyanide (HCN) content in a toxic local cassava variety “Rutuga” with an initial total HCN of 16.65%, free HCN of 9.19% and bound HCN (cyanoglycosides) of 7.46% in the fresh peeled root tubers was done to assess the effectiveness of aquatic and terrestrial (heap) fermentation in detoxifying cassava root tubers for obtaining dried product used in making flour. This was indirectly done by getting the difference in HCN content that remained after processing the root tubers using some traditional processing techniques. The findings indicated that aquatic fermentation in water from river Rwizi for days only removed 1.23% of total HCN, 0.05% of free HCN and 2.68% of Cyanoglycosides (bound HCN) while terrestrial (heap) fermentation for 4 days removed 50.33% of total HCN, 20.84% of free HCN and 86.66% of Cyanoglycosides (bound HCN). Therefore, terrestrial (heap) fermentation has a higher potential in removing total HCN, free HCN and cyanoglycosides (bound HCN) than aquatic fermentation, especially in water from river Rwizi.
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    Potential of Soaking and Sun-Drying in Detoxifying Toxic Cassava Root Tubers
    (International Journal of Food Science and Biotechnology, 2017) Andama, Morgan; Lejju, Julius B.; Oloya, Benson
    Root tubers of cassava (Manihot esculenta Crantz) have cyanogenic glucosides which liberate hydrogen cyanide (HCN) on hydrolysis in quantities that can be toxic to humans. As a result, several techniques have been used to detoxify the tubers including among others, soaking, sun-drying and fermentation which has been found to be the most effective. However, fermentation is associated with the growth of potentially mycotoxigenic moulds (fungi) which compromise the quality of the processed product hence suggesting the use of alternative mould free processing techniques like soaking and sun-drying. Therefore, this study investigated the potential of soaking and sun-drying in detoxifying root tubers of a toxic cassava variety, “Rutuga”, (interpreted as “strangler”) of cyanogens (total HCN, free HCN and bound HCN) in South Western Uganda. The cyanogens were determined by a standard titration method. The results indicated that soaking peeled cassava root tubers in cold distilled water for 4 days removed about 78% of bound HCN while sun-drying of peeled cassava chips for 5 days removed about 74% of free HCN. However, both methods are less effective in removing total HCN (soaking, 47%; sun-drying, 43%) due to the ineffectiveness of soaking and sun-drying in removing free HCN (21%) and bound HCN (3%) respectively. Hence a mixed approach employing both methods would be more appropriate in detoxifying cassava of total HCN.
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    Regeneration of indigenous trees in Mgahinga Gorilla National Park, Uganda
    (African Journal of Ecology, 2001) Lejju, Julius B.; Oryem-Origa, Hannington; Kasenene, John M.
    This study examines the regeneration of indigenous tree species in the formerly encroached area in Mgahinga Gorilla National Park (MGNP), south-western Uganda. Before gazetting in 1992, MGNP had basically been agricultural land for well over 50 years. The distribution of exotic vegetationwas established using a Geo- graphical Positioning System receiver and indigenous vegetation was sampled by establishment of quadrats along transect lines.
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    Vegetation dynamics in western Uganda during the last 1000 years: climate change or human induced environmental degradation?
    (African Journal of Ecology, 2009) Lejju, Julius B.
    A multi-proxy analysis of microfossils from sedimentary records, together with evidence from historical and archaeological data, has provided evidence of vegetation dynamics and human environment interactions in western Uganda for the last 1000 years. Pollen, fungal spores and phytoliths extracted from sediment cores obtained from a papyrus swamp at Munsa archaeological site indicate a relatively wet and forested environment in western Uganda prior to ca 1000 yr bp (cal 977–1159 ad). A subsequent decline in forest vegetation occurred from ca 920 yr bp (cal 1027–1207 ad). However, the deforestation period occurred during a wet period as registered in the River Nile water records, suggesting a human induced deforestation at Munsa rather than reduced precipitation. Increased numbers of herbivores, presumably domesticated cattle, postdeforestation are evidenced by the presence of dung fungal spores and broad accord with the archaeological evidence for initial occupation of the site at Munsa and the establishment of a mixed economy based on crops, cattle and iron working between 1000 and 1200 ad.
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    Vegetation regeneration in formerly degraded hilly areas of Rwampara, South Western Uganda
    (Journal of Ecology and The Natural Environment, 2015) Kyayesimira, Juliet; Lejju, Julius B.
    Rwampara hills located in South Western Uganda have long been subjected to intensive degradation due to increased human activities. The hills have been left bare as a result of vegetation clearing for agricultural land, charcoal burning and grazing. In 1998, the National Environmental Management Authority (NEMA) attempted to restore the degraded hilly areas with the aim of establishing the restoration potential. With the cooperation of the local people, NEMA set aside some parts of the hills to allow natural regeneration, while another parts were planted with exotic tree species mainly Eucalyptus spp. and Pinus patula. This paper presents findings of an assessment on the level of indigenous vegetation regeneration in the three zones namely; restored, planted and areas undergoing degradation due to grazing. The indigenous vegetation was sampled using nested quadrats set along line transects. The results indicate that species richness was different among the three habitat types with the highest number (17 species) recorded in the degraded (grazing) area, followed by the restored area (12 species) and the plantation had the least (10 species). Species density was highest in the restored zone (289.83/ha) and least (80.2/ha) in the plantation zone. The most common indigenous tree species regenerating in all the three study zones were; Olea europaea subsp. africana, Albizia adiathifolia and Markhamia lutea.