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Browsing by Author "Gwali, Samson"

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Building community based adaptation and resilience to climate change in Uganda
(World Vision, 2014) Gwali, Samson
Climate change and its impacts are already being felt in Uganda in the form of erratic rains, drought, famine, floods and landslides. These hazards do not only affect the crop life cycle but also the entire value chain from pre-production to post-harvest storage, marketing and transport. This ultimately leads to serious socioeconomic consequences in food security, health, and economic development. The reality of climate change is no longer in doubt and therefore, it is important to prepare and adapt to its impacts through appropriate adaptation and resilience strategies. However, resource – poor communities, households and individuals with least resources have the least capacity to adapt to the impacts. Since the linkages between climate change and land degradation are very high, there is a real need to devise community adaptation and resilience strategies that include sustainable land management. These adaptation and resilience strategies include a range of re-greening interventions, such as farmer managed natural regeneration and its variants such as “Ngitili” and community exclosures as well as conservation agricultural practices like “bocage” and “Zai” in West Africa. This paper presents a set of adaptation and resilience interventions implemented by the National Forestry Resources Research Institute (NaFORRI) in various parts of Uganda. These range from agroforestry, avoided deforestation to alternative livelihoods. It is, however, recommended that, in designing and implementing these community adaptation and resilience interventions, great care and consideration should be taken of the gender relations, wealth, power relations, culture and traditions existing in the local communities.
Diversity and composition of trees and shrubs in Kasagala forest: a semiarid savannah woodland in central Uganda
(African journal of ecology, 2010) Gwali, Samson; Okullo, Paul; Hafashimana, David; Mujuni Byabashaija, Denis
The diversity and composition of trees and shrubs of ‡5 cm diameter at breast height (DBH) were investigated in Kasagala woodland in central Uganda using 1 ha permanent sample plots. A total of 2745 trees and shrubs with a mean stem density of 686 ha)1 were recorded. These included 69 tree species belonging to 28 families and 47 genera. There was a larger number of small stems compared with that of larger stems. There was significant variation in stem size class distribution between the plots (F = 3.14, P = 0.027). The variation in stem densities (counts) across different size classes was significant (F = 8.31, P < 0.001). Species diversity was higher in the low lands compared with that in the elevated sites in the woodland. The species encountered were unevenly distributed across the plots. Species abundance was not significantly different across the sample plots (F = 2.63, P = 0.053). We suggest that the structure of the forest is typical of any regenerating forest, but other human influences may have played a part in the dominance of size classes <10 cm DBH. The causes of the present status and composition of the woodland require further investigation.
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, Fabrice
Fat 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.
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, Peter
Folk 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.
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-Marc
Shea 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.
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 Richard
This 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.
Local knowledge, identification and selection of shea tree (Vitellaria paradoxa) ethnovarieties for pre-breeding in Uganda
(The Journal of Agriculture and Natural Resources Sciences, 2020) Odoi, Juventine Boaz; Muchugi, Alice; Akias Okia, Clement; Gwali, Samson; Odong, Thomas L.
Local knowledge is important in characterizing and selecting shea tree ethnovarieties since the local communities have lived with the species for quite so long. The communities have developed their classification methods based on specific phenotypic traits used to distinguish one ethnovariety from another. This has helped them select and conserve specific genotypes of their interest on farm. Variants of shea trees exist in different populations known by the local communities. This study aimed at identifying and selecting high oil yielding shea tree “ethnovarieties” in Katakwi; Otuke; Amuru; Moyo; Arua and Nakasongola districts of Uganda using local knowledge. The districts were selected because of their long historical association with shea trees which has become part of their socio-cultural and economic lifestyle, so they have broad local knowledge about shea tree variations within their areas. The study aimed at identifying and selecting superior individual shea tree ethnovarieties with high oil yield using local knowledge for seed collection to raise a half sib population. Data was collected in the months of November and December 2017 from 246 shea tree farmers through interviews, 8 focus group discussions conducted, and 6 Key informer interviews with opinion leaders, civic leaders and local leaders in the districts. List of fifteen shea butter tree ethnovarieties with their descriptive characteristics was generated per district. 53.4% of the people who were interviewed were women and 46.4% were men. Data analysis using Statistical Package for Social Sciences (SPSS 20v) was run using multivariate analysis and multiple regression analysis to test for any differences in local knowledge of shea tree ethnovarietis. Differences in local knowledge in the research districts was moderately significant with P = 0.043, df = 4 and X2 =9.837.
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, Peter
Vitellaria 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.
Morphological variation among shea tree (Vitellaria paradoxa subsp. nilotica) ‘ethnovarieties’ in Uganda
(Genetic resources and crop evolution, 2012) Gwali, Samson; Nakabonge, Grace; Lamoris Okullo, John Bosco; Eilu, Gerald; Nyeko, Philip; Peter, Vuzi
Vitellaria 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 %), stemdiameter (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.
Nutritional prospects of jackfruit and its potential for improving dietary diversity in Uganda
(BMC research notes, 2022) Nantongo, Judith S.; Odoi, Juventine B.; Agaba, Hillary; Gwali, Samson
A sustainable way of providing essential nutrients from crops for the poor and undernourished is biofortification, through plant breeding. This study characterised the intraspecific variation of selected nutritional elements in the flakes and seeds of Ugandan jackfruit (Artocarpus heterophyllus) plus the phytochemical composition of leaves. The overall aim was to explore possibilities of selecting for varieties that are higher in selected essential nutrients. Selecting for nutrient dense crops has been mostly done for annual agricultural crops, and rarely for perennial fruit trees. Results: Uganda’s Jackfruit has high macronutrients, especially magnesium and calcium. This study revealed that the amounts of these macronutrients were higher than those found in commonly consumed fruits, giving jackfruit a nutritional advantage with respect to these nutrients. The varieties sampled also differed significantly (p < 0.01) for some nutrients such as vitamin C, crude fat, crude fibre, total soluble solids and juice yield, highlighting the potential for selection for targeted nutritional gains. The seeds however, had less amounts of most of the quantified nutrients that also differed among the varieties. Significant intraspecific variation of the leaf total phenolics was also observed. With regard to the quantified nutritional elements in the flakes, the ethno-varieties were separated in space along PC1 (p < 0.001), PC2 (p < 0.001) and PC3 (p < 0.01) indicating their distinctness.
Selectivity Of Forest Tree Species For Debarking By Elephants In Rabongo Forest- Murchison Falls National Park, Uganda
(Researchjournali’s Journal of Ecology, 2016) Odoi, Juventine Boaz; Babweteera, Fred; Gwali, Samson; Tweheyo, Mnason
Selectivity of the different forest tree species for debarking by elephants in a forest ecosystem is an important phenomenon for understanding the interactions between the large herbivores and the woody community in the tropical forest ecosystem. Here we present a long term investigation on elephant preference to forest trees debarking in Rabongo Forest spanning 20 years since 1992 in seven (7) one hectare plots established in 1992 distributed over 46 hactare in Rabongo Forest which is an important habitat for most large herbivores in Murchison Falls National Park. Diospyros abyssinica; Holoptelea grandis; Trichilea prieuriana and Cynometra alexandri were the most debarked/preferred tree species and also the most abundant in the forest in Rabongo Forest although the number of the debarked trees ≥ 10cm dbh reduced by 4%. Synthesis. There should be close monitoring of the number of elephants that visit Rabongo Forest over the years to relate with the number of stems debarked over the years to guide on the need to maintain the right elephant carrying capacity for the forest. We also recommend for further investigation for what attributes make the above tree species be preferred by elephants in Rabongo Forest
SilicoDArT and SNP markers for genetic diversity and population structure analysis of Trema orientalis; a fodder species
(Plos one, 2022) Ssali Nantongo, Judith; Odoi, Juventine Boaz; Agaba, Hillary; Gwali, Samson
Establishing the genetic diversity and population structure of a species can guide the selection of appropriate conservation and sustainable utilization strategies. Next-generation sequencing (NGS) approaches are increasingly being used to generate multi-locus data for genetic structure determination. This study presents the genetic structure of a fodder species -Trema orientalis based on two genome-wide high-throughput diversity array technology (DArT) markers; silicoDArT and single nucleotide polymorphisms (SNPs). Genotyping of 119 individuals generated 40,650 silicoDArT and 4767 SNP markers. Both marker types had a high average scoring reproducibility (>99%). Genetic relationships explored by principal coordinates analysis (PCoA) showed that the first principal coordinate axis explained most of the variation in both the SilicoDArT (34.2%) and SNP (89.6%) marker data. The average polymorphic information content did not highly differ between silicoDArT (0.22) and SNPs (0.17) suggesting minimal differences in informativeness in the two groups of markers. The, mean observed (Ho) and expected (He) heterozygosity were low and differed between the silicoDArT and SNPs respectively, estimated at Ho = 0.08 and He = 0.05 for silicoDArT and Ho = 0.23 and He = 0.19 for SNPs. The population of T. orientalis was moderately differentiated (FST = 0.20–0.53) and formed 2 distinct clusters based on maximum likelihood and principal coordinates analysis. Analysis of molecular variance revealed that clusters contributed more to the variation (46.3–60.8%) than individuals (32.9–31.2%). Overall, the results suggest a high relatedness of the individuals sampled and a threatened genetic potential of T. orientalis in the wild. Therefore, genetic management activities such as ex-situ germplasm management are required for the sustainability of the species. Ex-situ conservation efforts should involve core collection of individuals from different populations to capture efficient diversity. This study demonstrates the importance of silicoDArT and SNP makers in population structure and genetic diversity analysis of Trema orientalis, useful for future genome wide studies in the species.
Taxonomic diversity, distinctness, and abundance of tree and shrub species in Kasagala forest reserve in Uganda: implications for management and conservation policy decisions
(Tropical Conservation Science, 2010) Gwali, Samson; Okullo, Paul; Hafashimana, David; Mujuni Byabashaija, Denis
The successful management of natural resources requires access to adequate information on social, economic, ecological, and cultural changes in order to mitigate their impacts through conservation interventions. In most cases, such information is provided in the form of simple diversity indices, which may not predict the complex nature of species functioning in ecosystems. In this study, we used rank abundance, analysis of similarities (ANOSIM), similarity percentages (SIMPER), and taxonomic-diversity and distinctness indices to show the status of tree and shrub species in Kasagala forest reserve in central Uganda. Four 100 × 100 m plots were established in four vegetation strata of the strict nature reserve of the forest, and diameter at breast height (DBH) of trees and shrubs ≥ 5 cm measured. There was no significant difference in species abundance in the four vegetation strata (Kruskal Wallis H = 2.614, p = 0.453; ANOSIM: R = -0.334, p = 0.995). The taxonomic diversity and distinctness of the four vegetation types ranged between 2.414 and 2.786 while the taxonomic distinctness values ranged between 2.897 and 2.978. The taxonomic diversity of the forest is generally even, suggesting a homogeneous community. We suggest that the managers of the forest constitute a continuous monitoring program aimed at controlling the impact of anthropogenic factors, one of the main influences for such low taxonomic distinctness values observed for this forest.
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, Peter
Traditional 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.
Tree species diversity and abundance in coffee farms adjacent to areas of different disturbance histories in Mabira forest system, central Uganda
(International Journal of Biodiversity Science, Ecosystem Services & Management, 2015) Gwali, Samson; Agaba, Hillary; Balitta, Paul; Hafashimana, David; Nkandu, Joseph; Kuria, Anne; Pinard, Fabrice; Sinclair, Fergus
Coffee production in Uganda is done on small-scale farms containing a very significant tree component. However, there is little information on how tree species abundance, richness and diversity change in coffee farms as distance from forest changes. The main objectives of this study, therefore, were to assess (a) abundance and (b) diversity of tree species in the coffee production systems in proximity to disturbed and undisturbed forest around Mabira forest, one of Uganda’s Robusta coffee-growing areas. Seventy-nine 0.1 ha plots were established in nine villages close to undisturbed and disturbed forest, and over 5 km from the forest. A total of 875 trees belonging to 63 species were recorded. There was significant similarity in species composition among the three study sites (analysis of similarity R = 0.09, p < 0.01; analysis of variance: F3,12 = 0.353, p = 0.79). Non-metric dimensional scaling supported these findings (stress value = 0.224 at k = 2) and showed that tree species composition in the three proximity categories was very similar. These results demonstrate that tree species composition and diversity is similar in coffee farms regardless of their distance from the nearest natural forest and forest exploitation history.
Variability of phenolic and alkaloid content in different plant parts of Carissa edulis Vahl and Zanthoxylum chalybeum Engl.
(BMC research notes, 2018) Ssali Nantongo, Judith; Odoi, Juventine Boaz; Abigaba, Grace; Gwali, Samson
The objective of the study was to investigate the relative abundance and effect of post-harvest treatment on total phenolics (TP) and total alkaloids in the leaves and bark of Carissa edulis and Zanthoxylum chalybeum, which would give an indication of the suitability of leaves as alternative sources of medicine in these plant species. Results: Results indicated higher levels of total phenolics than total alkaloids in both of the species under both freezing and air drying conditions. While more alkaloids were found in leaves compared to bark, there was no difference in abundance of phenols between the plant parts of both species. Air drying preserved more TPs than freezing and the opposite was true for alkaloids. For sustainability, leaves are recommended as an alternative source of medicine instead of the preferred root or stem bark. However, the choice of whether to dry or freeze will depend on the specific compound of interest. Assessment of spatial variability of medicinal properties is highly recommended.
Variation in phenotypic traits of high oil yielding and early maturing shea trees (Vitellaria paradoxa) selected using local knowledge
(The Journal of Agriculture and Natural Resources Sciences, 2020) Boaz Odoi, Juventine; Odong, Thomas L.; Akias Okia, Clement; Muchugi, Alice; Gwali, Samson
Shea trees (vitellaria paradoxa) grow in West Nile, Teso, Lango and Acholi subregions of Uganda existing in different forms called enthnovarieties. Farmers from each of these subregions use phenotypic characteristics to differentiate one ethnovariety from the other. We conducted phenotypic characterization of shea trees identified by farmers as high oil yielding and early maturing and verified the farmers’ descriptors with standard phenotypic characterization. The study was conducted in the districts of Amuru, Arua, Katakwi, Moyo and Otuke between May and June 2017. One hundred eighty mature shea trees were purposively sampled from the five districts based on local knowledge. Descriptive statistics was then used to determine the variation among the different shea tree phenotypes characterized using standard descriptors. Twenty-seven ethnovarieties were recorded using farmers’ descriptors which were later on reduced to sixteen phenotypic traits using standard phenotypic descriptors related to fruit shapes, texture and kernel color. Variation in the kernel weights, fruit length and fruit width were significant (p < 0.05) and the shea fruit and seed width were highly correlated (78.6%) to their weights. We identified significant variation in shea trees within sites and fruit and seed weights between sites (p ≤ 0.001). Although variability within sites was significant, most parameters (height, diameter at breast height (dbh at 1.3 m), crown shape and height at first branching) were not. Shea fruit/kernel traits are important in characterizing varieties since they exhibit different forms across the sites since tree phenotypic attributes do not vary from location to location in Uganda. This lack of variability of ethnovarieties across the shea belt in Uganda is important in breeding for traits that can be acceptable by all the communities within the shea growing regions. The different shea ethnovarieties are therefore important in influencing policy decisions on their conservation.
Variation in seed and seedling traits of the different ethno-varieties of jackfruit, a potential fruit tree species for food security
(Trees, Forests and People, 2022) Ssali Nantongo, Judith; Mudondo, Scovia; Oluk, Richard; Agaba, Hillary; Gwali, Samson
A key component of the performance of plant seeds is the germination capability as well as seedling survival and vigor. Seed traits from five jackfruit ethno-varieties (infra-specific diversity as understood and managed by farmers) were assessed. A greenhouse experiment was conducted to determine the survival of seeds, emergence and germination rate. Seeds from different ethno-varieties differed in their length (F (4,145) = 6.31, p < 0.001). The difference was highest between seeds from white, orange or yellow ethno-varieties. The width also slightly differed among ethno-varieties (F (4,145) = 3.29, p < 0.05). The average fresh and dry weights tended to be higher in seeds from the soft ethno-variety than the rest of the ethno-varieties. Differences in the survival of seeds and germination rate were also exhibited among ethno-varieties, where the white ethno-variety showed the highest pre-emergence mortality but at the same time the least germination time. Over the six-week period of germination, the soft ethno-variety exhibited the highest root:shoot ratio but also grew faster than all other ethno-varieties. There is potential evidence of phylogenetic constraints on seed size, germination and seedling vigor. Optimum growth for most of the traits was achieved between 6 and 7 weeks after sowing, which can guide on the time seedlings should be left in the pots before being transferred to the field. Further progeny tests should be undertaken on these provenances in the field over a longer period so as to obtain better distinction of the growth traits among the ethno-varieties.
Variation in Seedling Germination and Growth in Five Populations Of vitellariaparadoxa C.F. Gaertn.subsp. Nilotica: A Threatened useful fruit Tree Species in Uganda
(Research Square, 2020) Boaz Odoi, Juventine; Odong, Thomas L.; Akias Okia, Clement; Lomoris Okullo, JohnBosco; Okao, Moses; Kabasindi, Harriet; Muchugi, Alice; Gwali, Samson
We studied seedlings germination and growth performance in an economically and socially important fruit tree species of Vitellaria paradoxaC.F. Gaertn.subsp. nilotica (Kotschy) in Uganda. The study aimed at determining variability in germination of the five shea tree seed lots and seedlings growth performance based on their growth traits. Five populations were considered from four agroecological zones of Uganda and 180 candidates plus trees (16 ethnovarieties) selected as seed trees based on their traits for faster growth and high oil yield. A total of 1204 biological seeds were collected and sown in a general tree nursery at Ngetta Zonal Agricultural Research and Development Institute (NgeZARDI)during the month of June 2018 in a randomized incomplete block design with three replications. Results: Significant variation (χ = 526; p < 0.01) was observed in seedling phenotypic traits within and between populations. Regression equation for height growth and leaf size index were given asy = 0.3787 + 12.671x and y = 0.6483 + 15.413x respectively. Root collar diameter was more correlated to leaf size index (0.425) than to height growth (0.30). Clustering of shea tree seedlings based on phenotypic growth traits revealed one aggregated cluster indicating that most of the seedlings from the five populations were similar (Jaccard index 0.92, p < 0.01). However, clustering based on SNP markers revealed three different populations. We recorded higher growth (χ = 708; p< 0.001) in Arua shea population (19.69 cm)compared to the population average (19.04 cm). Red seeded; thin pulped and hairy fruited shea tree ethnovarieties assumed faster growth than the rest. Conclusions: The phenotypic analysis of shea tree seedlings revealed some fast-growing genotypes from the five studied populations. Thesegenotypes can be selected for faster growth for shea tree breeding in Uganda.

Browsing by Author "Gwali, Samson"

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