Browsing by Author "Okullo, John Bosco Lamoris"
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Item Fat Content and Fatty Acid Profiles of Shea Tree (Vitellaria paradoxa subspecies nilotica) Ethno-Varieties in Uganda(Forests, Trees and Livelihoods, 2012) Gwali, Samson; Nakabonge, Grace; Okullo, John Bosco Lamoris; Eilu, Gerald; Forestier-Chiron, Nelly; Piombo, Georges; Davrieux, FabriceFat content and fatty acid composition are important nutritional properties of shea fruits. Farmers in Uganda report the presence of local shea tree ethno-varieties, but it is necessary to investigate their relative fat content and fatty acid composition to evaluate the economic importance of these ethno-varieties. Near infrared spectrophotometry (NIRS) was used to determine the fat content as well as the fatty acid composition of 44 ethno-varieties. Wet chemistry (soxtec petroleum – ether fat extraction and gas chromatography) methods were used to validate the results from NIRS. Fat content ranged from 43.9% to 58.4% while fatty acid composition was dominated by oleic (47–62%) and stearic acid (25–38%). Other fatty acids present were palmitic, vaccenic, linoleic, linolenic and arachidic acids. There was no significant difference in stearic, palmitic and oleic acid composition between ethno-varieties. However, significant variation of fat content, vaccenic and linoleic acids was observed between some ethno-varieties, perhaps due to locality, climatic and tree-to-tree differences. These findings can be utilized for the selection of ethno-varieties that are suitable for commercial production of shea oil in Uganda.Item Folk Classification of Shea Butter Tree (Vitellaria paradoxa subsp. nilotica) Ethno-varieties in Uganda(Ethnobotany research and applications, 2011) Gwali, Samson; Okullo, John Bosco Lamoris; Eilu, Gerald; Nakabonge, Grace; Nyeko, Philip; Vuzi, PeterFolk knowledge has been the basis for selection and improvement of many food crops such as potatoes, sorghum, yams, cassava and rice. In Uganda, there is strong potential to utilize folk knowledge to select and domesticate the shea butter tree (Vitellaria paradoxa C.F. Gaertn.subsp. nilotica (Kotschy) A.N. Henry & Chithra & N.C. Nair), an important economic tree species. Farmers report high variation in fruit yield, tree form and pulp taste. In this study, we documented shea tree folk classification by interviewing 300 respondents, 15 focus groups and 41 key informants across three farming systems of Uganda. Data were analyzed using Kruskall-Wallis and Spearman’s tests, Chi-square, Multivariate, Factor and Discriminant Function Analyses. Folk classification and nomenclature of shea tree ethno-varieties is based on fruit/nut organoleptic (color and taste) and morphological attributes. Interestingly, despite the socio-cultural importance of shea oil, it does not feature as a factor in the folk classification and nomenclature of shea tree ethno-varieties. There was no significant difference in classification knowledge across the three farming systems (Kruskal – Wallis χ2 = 28, df = 28, p > 0.05; Spearman’s R > 0.8, p < 0.0001) although there was significant influence from ethnicity of the respondents (Pillai’s trace = 0.817, p < 0.001). While this study provides a record of shea tree ethno-varieties and associated classification criteria, there is need to validate these ‘ethno-varieties’ using detailed morphological, biochemical and molecular analyses.Item Genetic Diversity in Shea Tree (Vitellaria Paradoxa Subspecies Nilotica) Ethno-Varieties in Uganda Assessed with Microsatellite Markers(Forests, Trees and Livelihoods, 2015) Gwali, Samson; Vaillant, Alexandre; Nakabonge, Grace; Okullo, John Bosco Lamoris; Eilu, Gerald; Muchugi, Alice; Bouvet, Jean-MarcShea trees (Vitellariaparadoxa C. F. Gaertn.) are classified locally into several folk or ethno-varieties by farmers in Uganda. It is, however, not clear whether this folk classification is supported by genetic differentiation between ethno-varieties. Genetically linked traits from folk classification are useful in conservation and breeding programmes. A total of 118 individual shea trees constituting 28 ethno-varieties sampled from three farming systems of Uganda were analysed using microsatellite markers. The number of alleles amplified per microsatellite locus ranged from 6 to 13 with an average of 9.5, with a total of 106 alleles identified. Observed (Ho) and expected heterozygosity (He) per locus ranged from 0.366 to 0.934 and 0.580 to 0.840, respectively. Mean Ho and He values for all loci across all ethno-varieties were 0.633 and 0.727, respectively. Analysis of molecular variance indicated that most of the variation (86.28%) occurred within individual trees; 11.25% was found among individual trees within ethno-varieties while 2.47% was found among ethno-varieties. The in-breeding index (f = 0.130), fixation index (θP = 0.025), gene flow value (Nm = 6.56) and cluster analysis show that all shea tree ethno-varieties were a single out-crossing population with very low genetic differentiation and high gene flow. The low differentiation in shea tree ethno-varieties was most likely due to the utilization of non-genetic traits in folk classification. However, while ethno-variety genetic structure was very weak, overall spatial population structure indicated the presence of three populations (West Nile, Northern and Teso). The West Nile population was more distantly related to the other two most likely due to isolation barriers such as the Rift Valley, Lake Albert and River Nile.Item Influence Of Rooting Media And Indole-3-Butyric Acid (IBA) Concentration On Rooting And Shoot Formation Of Warburgia Ugandensis Stem Cuttings(African Journal of Plant Science, 2011) Akwatulira, Florence; Gwali, Samson; Okullo, John Bosco Lamoris; Ssegawa, Paul; Tumwebaze, Susan Balaba; Mbwambo, John RichardThis study investigated the influence of different rooting media and indolebutryic acid (IBA) hormone concentration on root and shoot development in stem cuttings ofWarburgia ugandensis. Stem cuttings were treated with three different levels (0.3, 0.6 and 0.8% w/w) of IBA concentration (including a control- no IBA hormone) and propagated in three rooting media (milled pine bark, top forest soil and sand) under non-misting propagators. Data on root and shoot development, callusing, number and length of roots and shoots were analyzed using analysis of variance (ANOVA) and Chi square test. Callusing, root and shoot development were significantly (p<0.05) influenced by rooting media and IBA concentration. Milled pine bark and 0.8% w/w IBA concentration gave the highest percentages of stem cuttings that callused, rooted and shooted (38, 37, 41% and 57, 41, 59%), respectively. Similarly, milled pine bark and 0.8% w/w IBA concentration gave the greatest number and longest roots and shoots per stem cutting. Vegetative propagation of W. ugandensis through stem cuttings can be appropriately achieved by treating the cuttings with 0.8% w/w IBA hormone using milled pine bark as a growth medium.Item Morphological Variation among Shea Tree (Vitellaria paradoxa subsp. nilotica) ‘Ethnovarieties’ in Uganda(Genetic resources and crop evolution, 2012) Gwali, Samson; Nakabonge, Grace; Okullo, John Bosco Lamoris; Eilu, Gerald; Nyeko, Philip; Vuzi, PeterVitellaria paradoxa C. Gaertn. (shea butter tree) is an indigenous African tree species that is widely distributed in the dry areas of northern and eastern Uganda. The species is widely known for its oil which is used in cooking, cosmetics and traditional medicine. Local folk classification recognises the presence of different ethno-varieties on the basis of fruit and nut characters. In the present study, 176 trees representing 44 ethno-varieties from three farming systems of Uganda were assessed to determine the patterns of morphological variation and establish the congruence between morphological variation and folk classification. The results show high variation in pulp weight (CV = 35.9 %), stem diameter (CV = 28.48 %), fruit weight (CV = 27.81 %) and canopy diameter (CV = 26.69 %). There was a strong positive correlation between pulp and fruit weight (r = 0.963, p < 0.001), leaf length and leaf width (r = 0.652, p < 0.001) and between petiole length and leaf length (r = 0.788, p < 0.001). There was no underlying quantitative morphological structuring among the 44 ethno-varieties. Hierarchical cluster analysis using quantitative morphometric data produced three groups without clear aggregation based on ethnographic or geographic separation. However, a combination with qualitative traits as perceived by farmers provided good congruence with folk classification. Quantitative morphological data alone does not resolve any discrete forms of V. paradoxa that are related to folk classification. There is need to utilise biochemical and molecular markers to unravel the underlying variation for use in selection and improvement of shea butter tree ethno-varieties.Item Proximate composition of wild and on-farm Tamarindus indica LINN fruits in the agro-ecological zones of Uganda(J. Nutr. Health Food Eng, 2018) Okello, Jaspher; Okullo, John Bosco Lamoris; Eilu, Gerald; Nyeko, Philip; Obua, JosephProximate composition of wild and on-farm Tamarindus indica Linn fruits (pulp and seeds) were evaluated from three agro ecological zones and land use types in Uganda. The study objectives were: to compare the proximate composition of T. indica pulp and seeds among agro-ecological zones and land use types, and to determine the relationships between the pulp and seeds proximate composition variables among the agro-ecological zones and land use types in Uganda. Samples were analysed using standard procedures for moisture content, total ash, crude protein, crude fibre, crude oil and total carbohydrates. The results show that there were significant differences (P˂0.05) in the pulp and seeds proximate variables between agro-ecological zones except the seed ash content that showed significant difference between land use types. Only total ash contents showed significant interactions between agro-ecological zones and land use types while samples from the Lake Victoria Crescent agro-ecological zone were rich in proximate contents than other zones. The proximate composition revealed the presence of pulp and seed samples for: moisture content (27.40-31.60; 9.00-13.90%), total ash (4.60-5.00; 2.20-2.40%), crude protein (15.70-16.10; 4.30-4.50%), crude fibre (7.10-8.40; 8.00-9.00%), crude oil (0.27-0.29; 2.64- 2.98%) and total carbohydrates (50.20-56.20; 56.20-61.00%) respectively. There were no significant relationships among the proximate variables with agro-ecological zones and land use types. Both pulp and seeds showed good proximate contents, but the traditionally inedible seeds (thrown away after depulping) have more prospects and are recommended for consumption due to the high proximate contents than pulp, but first need to be processed before incorporation into human and animal diets.Item Traditional management and conservation of Shea trees (Vitellaria paradoxasubspeciesnilotica) in Uganda(Springer, 2016) Gwali, Samson; Okullo, John Bosco Lamoris; Eilu, Gerald; Nakabonge, Grace; Nyeko, Philip; Vuzi, PeterTraditional practices are universally recognised as a basis for conservation ofbiodiversity. However, such practices are often not included in natural resource conser-vation policies. This study assessed local conservation practices of shea trees (Vitellariaparadoxa) within different farming systems in Uganda and developed conservationguidelines for the species. The assessment involved 300 respondents, 15 focus groups and41 key informants. Content analysis was used to identify the most important managementand conservation practices. Local uses were categorised on the basis of shea tree productswhile differences in conservation practices were analysed using the Friedman test. Theresults show that eight shea tree products are used for 36 different purposes. Respondents’age significantly influenced their knowledge about the shea tree. Traditional conservationpractices include on-farm retention during cultivation and the use of folklore (mainly taboos), customs and rituals. Traditional management practices include weeding, bushburning, pollarding and pruning. Based on the current management and traditional con-servation practices, a framework for the conservation of shea trees is proposed for inte-gration into conservation policy decisions.