Agro-morphological characterization and investigations into the response of yellow Quality Protein Maize (QPM) genotypes to low soil pH
- Authors: Bobotyana, Simthandile
- Date: 2021-04
- Subjects: Corn as food , Plants--Drought tolerance
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20528 , vital:46087
- Description: Maize (Zea mays L) is an essential food grain crop in South Africa and is mainly grown under rainfed conditions by small-scale farmers. Quality Protein Maize (QPM) contains a higher level of two essential amino acids, tryptophan, and lysine when equated to normal maize. Therefore, the QPM in communities is a vital cereal where maize is a staple crop. Among the significant abiotic stresses that adversely affect maize productivity, such as soil fertility. Low soil pH or soil acidity results in nutrient deficiencies, as well as the toxicity of minerals such as manganese (Mn), aluminium (Al), and iron (Fe). The objectives of the study were to: (1) Characterize yellow QPM inbred lines and testcross hybrids for agro-morphological variability under optimum conditions, (2) Determine the response of QPM inbred lines and testcross hybrids to Al toxicity, and (3) Estimate the combining ability of QPM genotypes for the tolerance to Al toxicity. The laboratory assessment for tolerance to Al toxicity revealed a negative relationship between relative root growth RRG and hematoxylin staining; among the inbred lines, the genotype 8Y, 17Y, and 7Y had the highest RRG and net root growth (NRG) values and exhibited the highest tolerance to Al tolerance with the least hematoxylin staining. Inbred lines 12Y, 16Y, 19Y, 2Y, 20Y, 24Y, 30Y, 27Y, 34Y, 4Y, and 11Y were moderately tolerant. On the other hand, inbred lines 13Y, 18Y, and QSY5 had the least RRG were susceptible. Forty-four testcross hybrids were generated by crossing 22 QPM inbred lines with two open-pollinated variety (OPV) testers. These hybrids were evaluated together with five checks for different agronomic traits. The hybrids were planted in the summer season of 2017/18 and 2018/19 under rain-fed conditions 7 x 7 alpha lattice design was used. The significant variations among the genotypes for grain yield and most other agronomic traits under optimum, acidic conditions and across environments on combined analysis of variance. The hybrid was 14Y x NC (3.22 t/ha), followed by QSY5 x NC (3.02 t/ha) showed the highest yielding. The mean plant height was 226.23 cm, with ranges 197.60 to 254.85cm. The number of kernels per ear was 35, with a range from 29.45 to 40.25. Conversely, the mean ear length was 19.30 cm with a range of 17.65 to 20.95 cm, and the mean ear diameter ranged from 13,50 to 16,05 cm. The highest yielding hybrid, according to ranking, was 14Y x NC (2,93t/ha), which was ranked number 3, followed by 3Y x NC (2,83 t/ha), which was ranked number 4. Twenty-two yellow QPM inbred lines were evaluated for agro-morphological characteristics. A randomized complete block design with three replicates was used under acidic and normal soil conditions at two locations. The mean performance of inbred lines for grain yield ranged from 1.6 t/ha to 3.1 t/ha under optimum conditions, whereas it ranged from 1.1.t/ha to 1.7 t/ha under an acidic environment. The highest grain yielding genotypes under the optimum environment were 14Y, 7Y, and QSY5, while, in the acidic environment, the highest yielders were 3Y, QSY5, and 17Y. The lowest grain yielder under the optimum environment was 16Y at 1.5 t/ha, whereas 6Y, 7Y, 8Y, and 29Y were the most moderate yielders under the acidic environment. Grain yield displayed positive and significant (p<0,05) correlation with ear height (0.59), plant height (0.55), leaf length (0.18), number of leaves (0.37), number of ears per plot (0,54), number of kernels per row, number of rows per ear and thousand kernel weight. Combined ANOVA revealed that the environment effect was significant for all traits except the number of rows per ear and the number of ears in both environments. A total of 71 genotypes (22 inbred lines, forty-four single crosses, and five checks) were evaluated using a 7 x 7 alpha lattice design with two replications in combining ability. Across environments, the analysis showed a mean grain yield record of hybrids that ranged from 1.78 t/ha to 3.42 t/ha. Combined analysis showed only about 4 percent of the 44 hybrids had better grain yield than hybrid checks, whereas about 11 percent of the 44 hybrids had higher grain yield than two of the five hybrid checks. The highest yielding hybrid was 14Y x NC followed by QSY5 x NC. The Mid-parent heterosis (MPH) for grain yield ranged from -32.70 for 11YxObat to 16.50 percent for 14YxNC among the top-yielding genotypes. The highest positive mid-parent heterosis (MPH) for grain yield was observed in hybrid 14YxNC followed by QSY9xNC, QSY5xOBAT, 3YxNC, 13YxNC and 4YxOBAT, while the remaining hybrids exhibited negative estimates. Inbred lines' proportional contributions to the total variances were much higher than the testers for all traits. Whereas the inbred lines' proportional contribution was lower than the interaction of line x tester except on the number of ears which displayed the highest estimates of variances due to SCA effects, significant variation was observed. The GCA effects on grain yield in both environments generally showed no significant difference among inbred lines except for inbred lines such as QSY5 and 34Y but were positive. The selected crosses showed significant SCA effects in a few agronomic yield-related traits in the combined analysis. Among the hybrids, the only crosses that showed significant and positive SCA effects for grain yield were 25YxNC under optimum and 34YxObat under acidic environment. The inbred lines were assessed for tolerance to Al toxicity under laboratory conditions. Overall, the study identified soil acidity tolerant QPM inbred lines with an excellent combining ability for high-yielding QPM test hybrids, grain yield, and related traits. , Thesis (MSc) (Agriculture, Crop Science) -- University of Fort Hare, 2021
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- Date Issued: 2021-04
Development and assessment of rifampicin loaded self-microemulsifying drug delivery systems
- Authors: Mphaphuli, Mashudu Theodore
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178503 , vital:42945
- Description: Access restricted until April 2023. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2021
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- Date Issued: 2021-04
Development and characterisation of ciprofloxacin hydrochloride solid lipid nanoparticles for ocular delivery
- Authors: Dhege, Clarence
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178446 , vital:42940
- Description: Access restricted until April 2023. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2021
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- Date Issued: 2021-04
Exploring how Grade 9 Physical Science teachers mediate learning of the topic of chemical changes
- Authors: Likando, Orrice Munukayumbwa
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Chemistry -- Study and teaching (Secondary) -- Namibia , Culturally relevant pedagogy , Pedagogical content knowledge , Prior learning -- Namibia
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177918 , vital:42890
- Description: The examiners’ reports for 2013-2018 indicated that learners consistently perform poorly in questions based on chemical changes. My assumption is that the reason why learners are challenged with understanding the topic of chemical changes could be due to the way this topic is taught. It is against this background that this study explored how grade 9 Physical Science teachers mediated learning of the topic of chemical changes. The study is underpinned by an interpretive paradigm. Within the interpretive paradigm, a qualitative case study research design was employed. It was conducted at two different schools in the Otjozondjupa region with two Physical Science teachers. Data were collected using semi-structured interviews, lesson observations, stimulated recall interviews, and teachers’ reflections. The study is informed by Vygotsky’s socio-cultural theory together with Shulman’s pedagogical content knowledge as the theoretical frameworks. A thematic approach to data analysis was adopted. That is, qualitative data were analysed inductively to come up with sub-themes to form themes. Moreover, validation and trustworthiness were completed through data triangulation, member checking, and watching videotaped lessons with the participants. The findings of this study revealed that the topic of chemical changes has many examples which can be used during mediation. Teachers seemed to be aware of integrating learners’ experiences into their lessons. Furthermore, they were aware that they should improvise resources during mediation of learning. In contrast, during lesson observations, the findings revealed an imbalance between this awareness and the actual knowledge of using easily accessible materials, and the elicitation and integration of prior knowledge throughout the science lessons. Moreover, hands-on practical activities were lacking in the mediation process and instead, traditional methods of teaching tended to dominate. Nonetheless, teachers’ reflections influenced them to analyse and strengthen their lessons. Thus, the study recommends that there is a need for teachers to have mentorships and platforms which can expose them to the knowledge of different types of easily accessible materials. This might strengthen their PCK. Teachers are also encouraged to do some reflections after very lesson as these have a potential to influence their pedagogical practices. , Thesis (MEd) -- Faculty of Education, Education, 2021
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- Date Issued: 2021-04
Framing realities : a critical analysis of perspectival distortion in the film Alice by Czech Surrealist Jan Švankmajer
- Authors: Soutter, Simone
- Date: 2021-04
- Subjects: Švankmajer, Jan, 1934- -- Criticism and interpretation , Depression, Mental -- Exhibitions , Perception , Frames (Sociology) , Surrealism -- Influence , Cubism -- Influence , Surrealism in motion pictures , Depression, Mental in art
- Language: English
- Type: thesis , text , Masters , MFA
- Identifier: http://hdl.handle.net/10962/178365 , vital:42933
- Description: My MFA exhibition Through the looking glass; altered states of perception, explores my experience of mental distress: Major Depressive Disorder (MDD), through the medium of painting and multimedia collage. Situated in the Main Fine Art building on Rhodes University campus, this practical submission takes the form of a collection of oil paintings accompanied by an immersive wall of collaged experimentations, depicting the perspectival shifts I have experienced in coping with mental distress. The paintings explore concepts of framing and perspective, both literally and metaphorically in unpacking how our perceptions are manipulated by the way in which situations and concepts are framed. I use strategies and techniques drawn from the Surrealist and Cubist movements in order to depict my distorted experience of time and space, but also to tap into my own unconscious. In this mini-thesis: Framing realities; A critical analysis of perspectival distortion in the film Alice by Czech Surrealist Jan Švankmajer, I explore the strategies and concepts developed during the Surrealist and Cubist movements in relation to strategies used by Švankmajer in his disturbing interpretation of Alice’s Adventures into Wonderland. Here, he visually explores the psyche of an imaginative child. His unique interpretation is expressed through the combination of live-action film and stop-motion animation. I position my work in relation to themes proposed by Maurice Merleau-Ponty, Ernst Jentch, Sigmund Freud and Julia Kristeva. In the first Chapter: Framing and Perspectival shifts, I unpack framing and perspectival shifts exhibited in the Cubist (a physical shift), Dadaist (a social shift), and Surrealist (an unconscious shift) movements. In Chapter Two: A critical analysis of Alice by Jan Švankmajer, I engage in an analysis of themes (examined in the above art movements) relative to the film Alice. These are found objects and assemblages, ambiguity, distortion of scale, the Unconscious, the uncanny and multi-sensory modalities. Chapter Three: Through the Looking Glass; Altered states of perception, I discuss how the themes discussed in Chapter Two apply to my own body of work and how these themes are addressed with regards to my lived experience of mental disorder and distress. , Thesis (MFA) -- Faculty of Humanities, Fine Arts, 2021
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- Date Issued: 2021-04
In silico identification of selective novel hits against the active site of wild type mycobacterium tuberculosis pyrazinamidase and its mutants
- Authors: Gowo, Prudence
- Date: 2021-04
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Multidrug resistance , Antitubercular agents , Molecular dynamics , Hydrogen bonding , Ligand binding (Biochemistry) , Dynamic Residue Network
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178007 , vital:42898
- Description: The World Health Organization declared Tuberculosis a global health emergency and has set a goal to eradicate it by 2035. However, effective treatment and control of the disease is being hindered by the emerging Multi-Drug Resistant and Extensively Drug Resistant strains on the most effective first line prodrug, Pyrazinamide (PZA). Studies have shown that the main cause of PZA resistance is due to mutations in the pncA gene that codes for the target protein Pyrazinamidase (PZase). Therefore, this study aimed to identify novel drug compounds that bind to the active site of wild type PZase and study the dynamics of these potential anti-TB drugs in the mutant systems of PZase. This approach will aid in identifying drugs that may be repurposed for TB therapy and/or designed to counteract PZA resistance. This was achieved by screening 2089 DrugBank compounds against the whole wild type (WT) PZase protein in molecular docking using AutoDOCK4.2. Compound screening based on docking binding energy, hydrogen bonds, molecular weight and active site proximity identified 47 compounds meeting all the set selection criteria. The stability of these compounds were analysed in Molecular Dynamic (MD) simulations and were further studied in PZase mutant systems of A3P, A134V, A146V, D8G, D49A, D49G, D63G, H51P, H137R, L85R, L116R, Q10P, R140S, T61P, V139M and Y103S. Generally, mutant-ligand systems displayed little deviation from the WT systems. The compound systems remained compact, with less fluctuations and more hydrogen bond interactions throughout the simulation (DB00255, DB00655, DB00672, DB00782, DB00977, DB01196, DB04573, DB06414, DB08981, DB11181, DB11760, DB13867, DB13952). From this research study, potential drugs that may be repurposed for TB therapy were identified. Majority of these drugs are currently used in the treatment of hypertension, menopause disorders and inflammation. To further understand the mutant-ligand dynamic systems, calculations such as Dynamic Residue Network (DRN) may be done. Also, the bioactivity of these drugs on Mycobacterium tuberculosis may be studied in wet laboratory, to understand their clinical impart in vivo experiments. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
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- Date Issued: 2021-04