AWORUNSE, OLUWADUROTIMI SAMUEL and Covenant University, Theses (2023) ETHNOBOTANY AND GENETIC DIVERSITY ASSESSMENT OF Telfairia occidentalis HOOK F. (FLUTED PUMPKIN) IN SOUTHERN NIGERIA. Masters thesis, COVENANT UNIVERSITY.
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Abstract
The cultivation of Telfairia occidentalis constitutes a significant source of revenue for several small-holder farmers in Southern Nigeria. However, a decline in the indigenous knowledge and limited information on genetic diversity are major constraints to developing improved varieties in the species. The aim of the study was to evaluate indigenous knowledge variation, and phenotypic and genetic diversity of T. occidentalis in Southern Nigeria. Two hundred and ninety-five (295) respondents across four ethnic groups were interviewed. Uses cited by the respondents were grouped into categories. Quantitative ethnobotanical indices including fidelity level (FL %), use value (UV), and overall use value (OUV) of the different use categories were computed. Thirty-two (32) T. occidentalis landraces were evaluated for variability in 26 quantitative and 5 qualitative traits. The landraces were also assessed for molecular diversity using 8 start codon targeted (SCoT) primers and 18,469 single nucleotide polymorphism diversity array technology sequencing (DArTseq-SNP) markers. Six (6) use categories were identified, with utilisations as food and medicine exhibiting 100 % fidelity levels. The UVs differed significantly (p < 0.05) among the ethnic groups, gender, age group, and occupation, with the Efik/Ibibio linguistic group, females, aged respondents, and farmers possessing better ratings on local knowledge. The landraces displayed significant variability (p < 0.05) in all the quantitative traits evaluated except for the number of pods per plant and number of vines per plant. Principal component analysis (PCA) involved floral and vegetative traits as distinguishing characters that accounted for higher variabilities across the landraces. Cluster analysis based on the quantitative traits partitioned the landraces into five heterogeneous groups. A comparison of the cluster means revealed that ToIm002, ToIm003, ToOn002, ToIm002, ToRv003, ToRv001, ToRv002, and ToOn003 were early flowering and maturing landraces. Genetic diversity assessment using the SCoT markers amplified 66 fragments across the T. occidentalis genomes with an average polymorphic information content (PIC) of 0.77. A SCoT-based hierarchical clustering and principal component analysis (PCA) assembled the landraces into four clusters. Population-based genetic diversity using the SCoT markers showed a Nei’s gene diversity of 0.28 ± 0.01, indicating that the landraces were of a narrow genetic base. This was further corroborated by a high genetic identity and close genetic distance between the populations. The 18,469 DArTseq-SNPs exhibited a mean PIC value of 0.17. The mean observed heterozygosity (0.13) of the populations was lower than the expected (0.18), suggesting a low genetic diversity. Discriminant analysis of principal components (DAPC), analysis of molecular variance (AMOVA) and fixation index (Fst) estimates revealed no evidence for genetic differentiation and population structure between populations of the landraces. A DArTseq-SNP cluster analysis stratified the landraces into three admixed groups without reference to the collection regions. Overall, the study showed that the indigenous knowledge and use of T. occidentalis are structured along gender, age group, and occupation lines. Furthermore, both SCoT and DArTseq-SNP markers revealed a narrow genetic base for the plant, despite evidence of high morphological diversity. The results of this study have significant implications in the characterisation, conservation, improvement and utilization of fluted pumpkin.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Telfairia occidentalis, ethnobotany, genetic diversity, SCoT and DArTseq-SNP |
| Subjects: | Q Science > Q Science (General) Q Science > QH Natural history > QH301 Biology |
| Divisions: | Faculty of Medicine, Health and Life Sciences > School of Biological Sciences |
| Depositing User: | AKINWUMI |
| Date Deposited: | 03 Oct 2023 15:09 |
| Last Modified: | 03 Oct 2023 15:09 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/17340 |
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