Browsing by Author "Ssali Nantongo, Judith"

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    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.
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    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.
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    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.