Agro-morphological characterisation, nitrogen use efficiency and combining ability of quality protein maize (zea mays l.) genotypes for low nitrogen tolerance
- Authors: AdeOluwa, Olusola Oluyinka https://orcid.org/ 0000-0003-2145-7141
- Date: 2021-08
- Subjects: Corn -- Quality
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21501 , vital:48855 , http://id.loc.gov/authorities/subjects/sh85032715
- Description: Low nitrogen stress tolerant Quality Protein Maize (QPM) genotypes will be of great benefit to farmers for increasing productivity in nitrogen depleted soils in the Eastern Cape (EC) Province, South Africa (SA). The current study evaluated: (i) QPM inbred lines for tolerance to low soil nitrogen, (ii) the Nitrogen Use Efficiency (NUE) of different QPM inbred lines, (iii) the combining ability of QPM genotypes for tolerance to low nitrogen, grain yield, and other agro-morphological traits, and (iv) the agro-morphological characteristics and adaptation of QPM hybrids to environments of different production potential in the Eastern Cape, South Africa. Thirty-two white-seeded QPM inbred lines obtained from CIMMYT-Zimbabwe and Quality Seeds (PTY) LTD were evaluated for tolerance to low soil nitrogen stress using two nitrogen (N) treatment levels: 0 kg N ha-1 and 30 kg N ha-1 under both glasshouse and field conditions at the Crop Research farm, University of Fort Hare, in two planting seasons. The study aimed at assessing the response of QPM inbred lines to low N, with a view to identifying low N tolerant types under both glasshouse and field conditions. Shoot length stress tolerance index (SHL STI) indicated lines L23, L29, L27, L13, L16, L17, L31, L14, L18 and L22 to be low soil N tolerant from the glasshouse study. From the field study, low N Stress Tolerance Index (STI) identified inbred lines L23, L31, L26, L28, L25, L29, L32, L4, L6, L3 and L2 as low soil N tolerant. These inbred lines also had high grain yields (GY) in the field under 0 kg N ha-1 (all ranked within the top ten except L2). They also had the potential for stable yields across environments considering their high Yield Stability Index (YSI), Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Susceptibility Index (SSI) values. Both the glasshouse and field studies revealed inbred lines L22, L23, L26, L28, L25, L29 and L31 were common to both the glasshouse and field studies as being low soil N tolerant. These thirty-two parental QPM inbred lines were evaluated in the field for their nitrogen use efficiency (NUE) under five different nitrogen levels: 0, 30, 60, 90 and 120 kg N ha-1. The inbred lines studied under 0 kg N ha-1 and 30 kg N ha-1 indicated that N level expressed highly significant differences (P ≤ 0.001) for total nitrogen in biomass (Bio Total N), total nitrogen in grain (G Total N), grain yield (GY), nitrogen use efficiency (NUE) and almost all the indices estimated. The top six nutrient use efficient genotypes were L9, L14, L23, L25, L29 and L32 across N levels. However, the best and highest NUE was obtained from the lowest fertilizer dose, 30 kg N ha-1. Highly significant and positive correlation coefficients were found between Nitrogen Use Efficiency (NUE) and yield (+0.9), NUE and NUtE (+0.9), NUE and HI (Harvest Index) (+0.5), NUtE and yield (+0.99), HI and yield (+0.5) and NUtE and HI (+0.5). Thus, NUE, HI and NUtE could be good predictors of yield potential under low N soil conditions. Sixty-four testcross hybrids were generated from crossing these 32 QPM inbred lines with two QPM open pollinated varieties (OPVs) as testers in a line x tester design and were evaluated under 0 kg N ha-1 and 30 kg N ha-1 in the field. The objectives of the experiment were to: (i) identify high yielding hybrids with tolerance to low soil N in the EC; (ii) determine the combining abilities and mode of gene action for various traits under low and high nitrogen conditions; and (iii) group the inbred lines into heterotic groups for future use in the breeding program. Results revealed that under 30 kg N ha-1 (30N) condition, both additive and non-additive gene effects were observed with less importance of non-additive gene action for grain yield. Based on specific combining ability (SCA) effects, hybrids LNC22, LNC31, LOB22, LNC30, LNC29, LOB11, LNC18, LOB30, LOB19 and LNC24 showed outstanding performance under 0 kg N ha-1 (0N) condition with relatively acceptable SCA under 30N for yield. Inbred lines L6 (1.63), L22 (1.74), L29 (1.83) and L30 (1.24) showed positive and significant GCAs for grain yield under 0N. They were identified as the best combiners for grain yield as they were among the top ten performers for GCA under 0N. They can be very useful sources of low N tolerance genes. Two heterotic groups were formed under 0 kg N ha-1 and 30 kg N ha-1 conditions, and they will be useful for future hybrid development in the breeding program. Furthermore, these thirty-two QPM inbred lines were utilised as parental lines to generate seventy-six single cross hybrids. These single cross hybrids were evaluated across three environments of varying production potential in the Eastern Cape (EC), during the 2016/17 and 2017/18 summer seasons. Non-QPM hybrids namely PAN5Q649R and Phb31MO7BR, as well as QPM OPVs OBATANPA and Nelson's Choice were included in these preliminary variety trials (PVTs) as checks. Twenty-five hybrids expressing high values for the Smith – Hazel selection index were identified across sites over years. Among those hybrids were two checks, namely Q16 (PAN5Q649R) and Q33 (Phb31MO7BR). The top five high – yielding hybrids selected based on the selection index were considered to be the most productive, stable and adaptable based on the GGE biplot and AMMI stability values. None of these single cross hybrids over yielded the best hybrid check (Q16) in the current study. A high potential environment, Centane, was the ideal environments for evaluating genotypes in the present study. The studies showed inbred lines L22, L23, L26, L28, L25, L29 and L31 to be low N stress tolerant at 0 kg N ha-1 based on the low N stress tolerance indices under glasshouse and the field conditions; they were also among the top ten grain-yielders under field conditions at 0 kg N ha-1. Also, in the NUE study, they were found to be among the top ten most N-efficient inbred lines under low N soils, under 30 kg N ha-1, and were among the top twenty-four inbred lines with high NUE values across the N levels in the study. Inbred lines L29 and L22 also produced testcross hybrids that were among the top twenty based on GY under 0 kg N ha-1. The testcross hybrids produced from these inbred lines were also among the top twenty-five with outstanding SCA effects for GY. These inbred lines were also parental lines of some of the top twenty- five best hybrids selected based on the Smith – Hazel selection index in the PVT study. Inbred lines L22, L23, L26, L28, L25, L29 and L31 can therefore further be evaluated and used as sources of N-tolerance genes in QPM breeding programs. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
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- Date Issued: 2021-08
The effect of marketing capabilities on the competitive advantage of Small Medium and Micro Enterprises in OR Tambo District Municipality, Eastern Cape
- Authors: Mpongwana, Konaye https://orcid.org/0000-0003-4105-1536
- Date: 2020-01
- Subjects: Market segmentation , Marketing -- Management
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20197 , vital:45407
- Description: It is usually understood that the development of technological marketing capabilities by firms provides them with immense opportunities to transform their business practices and strategies, to strategically position themselves in the market and enhance firm performance. The main objective of this study was to determine the effect of marketing capabilities (Intellectual capital, marketing strategy and market orientation) on the competitive advantage of SMMEs. Prior research has that early development of marketing capabilities enables firms to achieve competitive advantage. The issue to be attended to will be to identify the connection between the incorrect marketing capabilities and failure of SMMEs, if there is any. Furthermore, a thorough investigation looking at how the reduction of failure of SMMEs can be realised by investigating the marketing capabilities of SMMEs. Quantitative research approach was used in the study, with a population of 200 SMMEs, the Raosoft calculator is also used to calculate the sample size of 100 SMMEs which were used to collect the primary data of the study. Convenience sampling method was used by the researcher. The findings also revealed that SMMEs adopt new and advanced technologies when marketing their products and services. The study recommends that SMME Owners/ Managers should consider spending a higher proportion of their time and money engaging in activities related to marketing throughout the life of their business. Therefore, it has concluded that effective deployment of marketing capabilities can lead to competitive advantage and greater performance. , Thesis (MCom) -- Faculty of Management and Commerce, 2020
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- Date Issued: 2020-01
Production and biochemical characterization of new bioflocculants from bacteria isolated from freshwater and marine environments of the Eastern Cape in South Africa
- Authors: Mabinya, Leonard Vuyani https://orcid.org/0000-0002-0682-7282
- Date: 2013-01
- Subjects: Flocculation , Bacteria
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/24228 , vital:62445
- Description: The production and characterization of bioflocculants produced by three bacteria belonging to Arthrobacter, Halomonas and Micrococcus genera and isolated from freshwater and marine environments were evaluated both as axenic cultures and as consortia. The influences of cultutre conditions such as carbon, nitrogen and metal ions sources, as well as initial pH on bioflocculant production by individual isolates were investigated. Both Arthrobacter sp. Raats and Halomonas sp. Okoh utilized urea as a nitrogen source of choice for optimal production of the bioflocculants with Micrococcus sp. Leo having a preference for peptone. All three strains differed in as far as the carbon source of choice was concerned with lactose, glucose and sucrose the preferred carbon sources respectively. Also, all three bacterial strains produced an extracellular bioflocculant aerobically but an intial pH 7.0 of the culture media was suitable for both Arthrobacter sp. Raats and Halomonas sp. Okoh with a slightly alkaline pH of 9.0 preferred by Micrococcus sp. Leo. The presence of Mg2+ cations stimulated bioflocculant production by both Arthrobacter sp. Raats and Micrococcus sp. Leo while Ca2+ resulted in more efficient bioflocculant production by Halomonas sp. Okoh. Chemical analyses revealed the bioflocculants produced by both Halomonas sp. Okoh and Micrococcus sp. Leo to be predominantly polysaccharides whereas Arthrobacter sp. Raats produced principally a glycoprotein composed of about 56percent protein and 25percent total carbohydrate. Response surface methodology (RSM) was used to optimize production medium for bioflocculant production by a consortium of Halomonas sp. Okoh and Micrococcus sp. Leo. Plackett-Burman experimental design showed that fructose, ammonium sulphate and MgCl2 were significant in the high yield of the bioflocculant. Furthermore, central composite design showed that optimal concentration of these critical nutritional sources were 16.14 g/L, 1.55 g/L and 1.88 g/L for fructose, ammonium sulphate and MgCl2 respectively. Quantification of the bioflocculant showed a yield of 6.43 g/L which was in close accord with the predicted value of 6.51 g/L. FTIR spectrometry of the bioflocculant indicated the presence of carboxyl, hydroxyl and amino groups, typical for heteropolysaccharide, while SEM imaging revealed a lattice-like structure. The efficiency of the nutrient optimization suggests suitability for industrial applicability. , Thesis (PhD) -- Faculty of Science and Agriculture, 2013
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- Date Issued: 2013-01
Experiences of community psychiatric nurses and guardians of discharged psychiatric patients on the effectiveness of community mental health services of the Zomba district in Malawi
- Authors: Kachingwe, Bertha Maggie
- Date: 2011-12
- Subjects: Psychiatric nursing , Community mental health services
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24183 , vital:62440
- Description: Sturdy: Experiences of community psychiatric nurses and guardians of discharged psychiatric patients on the effectiveness of community mental health services of the Zomba District in Malawi. Purpose: The purpose of the study was to explore and describe the experiences of community psychiatric nurses and guardians of discharged psychiatric patients with regard to failure of Community Mental Health Services of the Zomba District, and make recommendations to improve community mental health services. Although such services exist, their effectiveness is unknown, either from the nurses’ point of view or from the consumers’ point of view. Method: A qualitative approach with phenomenological research design was used to answer the research question on the effectiveness of the services. This method was chosen because the researcher was committed to explore the lived in-depth experiences of the study participants. A purposive sampling method was used to select participants for the study, who were selected based on their knowledge of the phenomena. Data collection Instruments used were unstructured interviews, using face- to- face interaction. One broad, open-ended question was used to gather information from the participants. Data analysis was done using Atlas.ti software to help the researcher uncover complex phenomena hidden in the text. Findings: Participants from both groups overwhelmingly reported that community mental health services were not effective. Four categories and eleven themes of barriers impacting on ineffective services emerged from the nurses. For example; Inadequate service provision related to unavailability of resources (human, time and materials). Themes hindering effective services emerged from the guardians for example; Services not accessible related to inconsistent appointment dates, shortage of medications and poor economic status of participants. , Thesis (MCur) -- Faculty of Science and Agriculture, 2011
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- Date Issued: 2011-12
A comparison of ethical models for conflict resolution in the African context
- Authors: Mbangu, Muyingi
- Date: 2008
- Subjects: Africa -- Politics and government , Conflict management
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/25052 , vital:63948
- Description: Remarkably little research has been done about the potential of ethical models for violent conflict resolution in the African context. I will argue here that ethical models such as Utilitarianism, Deontologism, Virtue ethics, and African ethics can exert influence to help resolve conflict situations peacefully for the sake of African civilians generally and the DRC civilians in particular. This influence firstly becomes visible in the fact that ethical models can guide conflict resolution attempts to bring about conditions of peace, justice and freedom among African civilians in whichever nations state they find themselves. Secondly, ethical models can be established in the resolution of conflict for a lasting peace in the African context, and lastly, ethical models can be proposed as a guideline for all African leaders to lead their countries in peace. The conclusion I draw is that a normative framework of ethical models can be applied in conflict resolution in the African context. This framework draws on all four models, but leans toward deontology because of its strictness or rigour of universal rules or principles in any situation. , Thesis (MA) -- Faculty of Social Sciences and Humanities, 2008
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- Date Issued: 2008