Water-use efficiency Decision Support System for irrigation in smallholder farms using machine learning
- Authors: Mndela, Yonela
- Date: 2024-09
- Subjects: Irrigation farming , Agriculture--Economic aspects , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29933 , vital:79207
- Description: Small-scale farmers in arid and semi-arid regions rely mostly on irrigation to boost agricultural production and reduce dependency on unpredictable rainfall. However, due to poor farming knowledge, the efficiency of irrigation in these farms is low as crops are irrigated equally across the entire field without considering spatial variations in crop water requirements. This study was aimed at devising irrigation scheduling for various small-scale crops cabbage, sweet potato, maize, garlic, Florida broadleaf mustard, Solanum Retroflexum, green beans, sugar beans and spinach in the Mutale River catchment, based on changes in crop water status obtained from the regression models generated from the association between remotely sensed data and field data. Remotely sensed data in the form of unmanned aerial vehicle UAV imagery was used as the base from which crop spectral signatures and spatial patterns in water content were obtained. Endmember spectral analysis was performed to analyse spectral patterns of the crops. The Green Normalized Difference Vegetation Index GNDVI, Normalized Difference Vegetation Index NDVI, Normalized Difference Red edge NDRE, and Optimized Soil Adjusted Vegetation Index OSAVI were generated from the UAV imagery to serve as the base from which crops were characterized, and spatial patterns in water content were observed. Field survey method was carried out on the various crop plots to acquire leaf water content data fresh weight, turgid weight, and dry weight. The stratified random sampling method was used to select crops from which leaf samples would be extracted for measurements, based on crop type and growth stage. The measured leaf water content data was used to compute the Relative Water Content RWC which was used as an indication of water content in the crops. Field based RWC was used to observe spatial patterns in crop water content, as well as calibration and validation of crop water content empirical models retrieved from the Unmanned Aerial Vehicle UAV imagery. The Levene’s k-comparison test was performed to determine the spatial patterns in crop water content. A simple linear regression technique was employed to determine the nature and significance of the association of field based RWC and spectral vegetation indices. The linear regressions with the highest coefficient of determination r2 were used for modelling crop water content using spectral vegetation indices maps as the explanatory variable in the models. The time series regression technique was employed to simulate water changes across the crop types in the study area. The endmember spectral analysis results revealed variations in the spectral reflectance patterns of crops across the UAV spectral channels. A slight difference in spectral reflectance was noted across Solanum Retroflexum, green beans, sweet potato, pepper, maize, and sugar beans, as they all exhibited low and high reflectance in the red and near infrared channels, respectively. The spectral patterns of peas and cabbage were relatively easy to distinguish from the other crops because they exhibited high reflectance in the red-edge and green channels, respectively. The analysis of the spectral vegetation maps revealed that GNDVI, NDVI, NDRE, and OSAVI can be used to observe spatial variability of water content across various crops. In this study, the healthier plants were identified by a higher spectral index value (closer to +1) while unhealthy plants showed lower values closer to -1. The linear regression analysis revealed a significant association between GNDVI and water content of sweet potato, maize, sugar beans, and Florida broadleaf mustard, with r2 values of 0.948, 0.995, 0.978, and 0.953, respectively. NDVI revealed a strong association with water content of Solanum Retroflexum, pepper, and cabbage, with the r2 values of 0.949, 0.956, and 0.995, respectively. NDRE, on the other hand, revealed a strong relationship with water content in peas and green beans, with r2 values of 0.961, and 0.974, respectively. OSAVI was observed to be the least sensitive spectral index to water content across the surveyed crop types. The remotely sensed models produced in this study revealed that, RWC can be successfully predicted from UAV imagery. Time series regression revealed a gradual decrease in water content with an increase in the number of days for all the surveyed crops. The simulations revealed that Solanum Retroflexum, sweet potato, maize, sugar beans, and Florida Broadleaf Mustard reached their respective wilting points at day four after irrigation, implying that irrigation of these crops should be scheduled after every four 4 days basis. Peas, green beans, pepper, and cabbage reached their respective wilting points at day five after irrigation, implying that irrigation of these crops should be scheduled after every five days. The results of this study revealed that, with the current irrigation scheduling interval of seven days in the study area, the crops are subjected to water stress which has a huge impact on the quality and yield of the crops. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024-09
- Authors: Mndela, Yonela
- Date: 2024-09
- Subjects: Irrigation farming , Agriculture--Economic aspects , Agricultural development projects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29933 , vital:79207
- Description: Small-scale farmers in arid and semi-arid regions rely mostly on irrigation to boost agricultural production and reduce dependency on unpredictable rainfall. However, due to poor farming knowledge, the efficiency of irrigation in these farms is low as crops are irrigated equally across the entire field without considering spatial variations in crop water requirements. This study was aimed at devising irrigation scheduling for various small-scale crops cabbage, sweet potato, maize, garlic, Florida broadleaf mustard, Solanum Retroflexum, green beans, sugar beans and spinach in the Mutale River catchment, based on changes in crop water status obtained from the regression models generated from the association between remotely sensed data and field data. Remotely sensed data in the form of unmanned aerial vehicle UAV imagery was used as the base from which crop spectral signatures and spatial patterns in water content were obtained. Endmember spectral analysis was performed to analyse spectral patterns of the crops. The Green Normalized Difference Vegetation Index GNDVI, Normalized Difference Vegetation Index NDVI, Normalized Difference Red edge NDRE, and Optimized Soil Adjusted Vegetation Index OSAVI were generated from the UAV imagery to serve as the base from which crops were characterized, and spatial patterns in water content were observed. Field survey method was carried out on the various crop plots to acquire leaf water content data fresh weight, turgid weight, and dry weight. The stratified random sampling method was used to select crops from which leaf samples would be extracted for measurements, based on crop type and growth stage. The measured leaf water content data was used to compute the Relative Water Content RWC which was used as an indication of water content in the crops. Field based RWC was used to observe spatial patterns in crop water content, as well as calibration and validation of crop water content empirical models retrieved from the Unmanned Aerial Vehicle UAV imagery. The Levene’s k-comparison test was performed to determine the spatial patterns in crop water content. A simple linear regression technique was employed to determine the nature and significance of the association of field based RWC and spectral vegetation indices. The linear regressions with the highest coefficient of determination r2 were used for modelling crop water content using spectral vegetation indices maps as the explanatory variable in the models. The time series regression technique was employed to simulate water changes across the crop types in the study area. The endmember spectral analysis results revealed variations in the spectral reflectance patterns of crops across the UAV spectral channels. A slight difference in spectral reflectance was noted across Solanum Retroflexum, green beans, sweet potato, pepper, maize, and sugar beans, as they all exhibited low and high reflectance in the red and near infrared channels, respectively. The spectral patterns of peas and cabbage were relatively easy to distinguish from the other crops because they exhibited high reflectance in the red-edge and green channels, respectively. The analysis of the spectral vegetation maps revealed that GNDVI, NDVI, NDRE, and OSAVI can be used to observe spatial variability of water content across various crops. In this study, the healthier plants were identified by a higher spectral index value (closer to +1) while unhealthy plants showed lower values closer to -1. The linear regression analysis revealed a significant association between GNDVI and water content of sweet potato, maize, sugar beans, and Florida broadleaf mustard, with r2 values of 0.948, 0.995, 0.978, and 0.953, respectively. NDVI revealed a strong association with water content of Solanum Retroflexum, pepper, and cabbage, with the r2 values of 0.949, 0.956, and 0.995, respectively. NDRE, on the other hand, revealed a strong relationship with water content in peas and green beans, with r2 values of 0.961, and 0.974, respectively. OSAVI was observed to be the least sensitive spectral index to water content across the surveyed crop types. The remotely sensed models produced in this study revealed that, RWC can be successfully predicted from UAV imagery. Time series regression revealed a gradual decrease in water content with an increase in the number of days for all the surveyed crops. The simulations revealed that Solanum Retroflexum, sweet potato, maize, sugar beans, and Florida Broadleaf Mustard reached their respective wilting points at day four after irrigation, implying that irrigation of these crops should be scheduled after every four 4 days basis. Peas, green beans, pepper, and cabbage reached their respective wilting points at day five after irrigation, implying that irrigation of these crops should be scheduled after every five days. The results of this study revealed that, with the current irrigation scheduling interval of seven days in the study area, the crops are subjected to water stress which has a huge impact on the quality and yield of the crops. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024-09
Optimization of automatic speech recognition under noisy environment using machine learning techniques
- Authors: Yamkela, Melane
- Date: 2024-04
- Subjects: Automatic speech recognition , Speech processing systems , Computational linguistics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29954 , vital:79216
- Description: Speech recognition technology is a fascinating field that enables machines to comprehend and interpret human speech. It allows users to interact with computers, smartphones, and other devices, using spoken commands rather than traditional input methods, like typing. Speech recognition systems analyse audio input, typically in the form of spoken words or phrases, and convert them into text or commands that computers can understand. The journey of speech recognition technology has been remarkable, evolving from simple command-based systems to advanced natural language processing algorithms capable of understanding context, accents, and even emotions. While speech recognition has made significant strides, challenges persist, particularly in accurately handling noisy environments and distinguishing between similarsounding words. This study aimed at developing an optimal automatic speech recognition system under a noisy environment, using machine learning techniques. In addition, the study aimed at evaluating the performance of the developed system. Speech recognition methodology involves several key steps to accurately transform verbal words into written commands or text, such as - Audio Input, Preprocessing, Feature Extraction, Acoustic Modeling, and Language Modeling. The model was developed using Google Collab and TensorFlow, an open-source machinelearning platform. This model used a transformer-hugging face, which is a pre-trained model. Transformers deploy convolutional neural networks that were trained with data collected by Facebook wac2 vec. For evaluation, the model made use of a confusion matrix, precision and accuracy metrics; the model was tested on real-time data and good results were achieved. Evaluation is continuing to observe the model's performance under different noisy backgrounds. This research adds to the corpus of knowledge, particularly in the field of speech recognition and for future work, the study will seek to use large live data and also investigate the error rate. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Yamkela, Melane
- Date: 2024-04
- Subjects: Automatic speech recognition , Speech processing systems , Computational linguistics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29954 , vital:79216
- Description: Speech recognition technology is a fascinating field that enables machines to comprehend and interpret human speech. It allows users to interact with computers, smartphones, and other devices, using spoken commands rather than traditional input methods, like typing. Speech recognition systems analyse audio input, typically in the form of spoken words or phrases, and convert them into text or commands that computers can understand. The journey of speech recognition technology has been remarkable, evolving from simple command-based systems to advanced natural language processing algorithms capable of understanding context, accents, and even emotions. While speech recognition has made significant strides, challenges persist, particularly in accurately handling noisy environments and distinguishing between similarsounding words. This study aimed at developing an optimal automatic speech recognition system under a noisy environment, using machine learning techniques. In addition, the study aimed at evaluating the performance of the developed system. Speech recognition methodology involves several key steps to accurately transform verbal words into written commands or text, such as - Audio Input, Preprocessing, Feature Extraction, Acoustic Modeling, and Language Modeling. The model was developed using Google Collab and TensorFlow, an open-source machinelearning platform. This model used a transformer-hugging face, which is a pre-trained model. Transformers deploy convolutional neural networks that were trained with data collected by Facebook wac2 vec. For evaluation, the model made use of a confusion matrix, precision and accuracy metrics; the model was tested on real-time data and good results were achieved. Evaluation is continuing to observe the model's performance under different noisy backgrounds. This research adds to the corpus of knowledge, particularly in the field of speech recognition and for future work, the study will seek to use large live data and also investigate the error rate. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024-04
A hybrid optimisation model for water quality prediction using Naive Bayes and SMO algorithms:: The bagging technique
- Authors: Mcedani, Lazola Asadumodwa
- Date: 2024-03
- Subjects: Water quality , Learning classifier systems , Time-series analysis--Data processing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29911 , vital:79189
- Description: This study comprehensively evaluates machine learning classifiers to predict water quality using time-series data. The objective is to identify the most effective classifiers, assess the influence of reconfigurations on their performance, and construct a hybrid model using the superior classifiers. Additionally, the study seeks to ascertain the most suitable ensemble technique. The methodology incorporates the knowledge discovery in databases KDD process and scrutinises 56 classifiers available in WEKA. The investigation reveals support vector machine optimisation SMO and Naive Bayes as the leading classifiers, with 74.37 percent and 70.01 percent prediction accuracies, respectively. Performance enhancements were observed following reconfigurations, with the refined SMO model achieving an accuracy of 79.9827 percent on a novel unseen dataset and the adjusted Naive Bayes model reaching 78.3784 percent. The hybrid model, which amalgamates Naive Bayes and SMO, exhibited improved accuracy without compromising efficiency. Bagging was identified as the most influential ensemble technique, delivering the highest accuracy and overall model efficacy. Bagging achieves a prediction accuracy of 86.4865 percent, surpassing the best-performing base model. It also demonstrates a Kappa statistic of 0.7628, indicating substantial agreement with the ground truth, along with an impressive F-measure of 0.859 and other notable metrics, highlighting its robust performance across various evaluation criteria. This study contributes to developing water quality prediction models, providing valuable insights for researchers and practitioners, and enabling more informed decision-making in environmental management, public health, and resource allocation. The research advances algorithm design, optimises techniques, and pioneers novel hybrid models while offering a robust evaluation framework to compare the performance of various classifiers and ensemble techniques. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024-03
- Authors: Mcedani, Lazola Asadumodwa
- Date: 2024-03
- Subjects: Water quality , Learning classifier systems , Time-series analysis--Data processing
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29911 , vital:79189
- Description: This study comprehensively evaluates machine learning classifiers to predict water quality using time-series data. The objective is to identify the most effective classifiers, assess the influence of reconfigurations on their performance, and construct a hybrid model using the superior classifiers. Additionally, the study seeks to ascertain the most suitable ensemble technique. The methodology incorporates the knowledge discovery in databases KDD process and scrutinises 56 classifiers available in WEKA. The investigation reveals support vector machine optimisation SMO and Naive Bayes as the leading classifiers, with 74.37 percent and 70.01 percent prediction accuracies, respectively. Performance enhancements were observed following reconfigurations, with the refined SMO model achieving an accuracy of 79.9827 percent on a novel unseen dataset and the adjusted Naive Bayes model reaching 78.3784 percent. The hybrid model, which amalgamates Naive Bayes and SMO, exhibited improved accuracy without compromising efficiency. Bagging was identified as the most influential ensemble technique, delivering the highest accuracy and overall model efficacy. Bagging achieves a prediction accuracy of 86.4865 percent, surpassing the best-performing base model. It also demonstrates a Kappa statistic of 0.7628, indicating substantial agreement with the ground truth, along with an impressive F-measure of 0.859 and other notable metrics, highlighting its robust performance across various evaluation criteria. This study contributes to developing water quality prediction models, providing valuable insights for researchers and practitioners, and enabling more informed decision-making in environmental management, public health, and resource allocation. The research advances algorithm design, optimises techniques, and pioneers novel hybrid models while offering a robust evaluation framework to compare the performance of various classifiers and ensemble techniques. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024-03
A longitudinal study on the distribution of SARS-CoV-2 genome in wastewaters from typical urban and peri - urban communities in the Buffalo City Municipality, Eastern Cape, South Africa
- Authors: Ngqwala, Balisa
- Date: 2024
- Subjects: COVID-19 (Disease) , SARS-CoV-2 disease , SARS coronavirus 2 disease
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29888 , vital:79184
- Description: The global health system and economy has been convulsed by the origin of Severe Acute respiratory Syndrome Coronavirus 2 SARS-CoV-2 infections which causes Coronavirus disease 2019 COVID-19. SARS-CoV-2 infections has become a recent global health concern, with drastic increase of illnesses and mortality cases. COVID- 19 originated in Wuhan, the capital of Hubei province in the People’s Republic of China, nonetheless, the diseases had spread to over 229 countries to date. COVID-19 clinical spectrum varies from mild fulminant pneumonia with acute respiratory distress to asymptomatic or mild respiratory infection or multi-organ failure resulting in death. Over 691 million cases with approximately 6.9 million fatalities have been recorded due to COVID-19 globally. The main route of transmission of this disease is reported to be respiratory droplets from an infected individual. However, previous studies demonstrate the presence of the virus in faces and urine as SARS-CoV-2 RNA fragments have been detected in wastewater and river waters around the world. The focal aim of this study was to profile and compare the incidence of SARS-COV-2 genomes in wastewater samples obtained from wastewater treatment facilities located in typical urban and peri-urban communities within the Buffalo City Municipality in the Eastern Cape Province, South Africa. Raw wastewater (influent) samples were collected by the grab sampling technique on a weekly basis for a period of 12 months sampling regime. Ribonucleic Acids were extracted from the collected wastewater WW samples, using the commercial QIAGEN Powersoil Total RNA Extraction kit, following the manufacturer’s guideline. The extracted RNA samples were further profiled for the presence and quantity of SARS-COV-2 genomes from the collected wastewate samples by Quantitative Real Time Polymerase Chain Reaction qRT-PCR technique. The findings of this study revealed the prevalence of SARS-COV-2 genomes from the raw wastewater samples across the urban and peri-urban study sites with the concentrations that ranged from 0.22 × 103 to 17.60 × 103 genome copies per millilitre GC/mL. Furthermore, various environmental matrices were utilized in the present study to estimate the potential health risk to plant operators associated with the exposure toSARS-CoV-2 viral particles using the quantitative microbiological risk assessment QMRA model. Different exposure scenarios were employed for the QMRA model and the findings indicate a probability of infection ranging from 0.93 percent to 37.81 percent across the study sites. Overall, the findings obtained in the current study highlight the bothersome concerns that reveal sewage systems as a transmission pathway for the dissemination of SARS-CoV-2 genomes in the environment. Therefore, this study accentuates the need for continued surveillance and constant environmental monitoring of SARS-CoV-2 other microbial pathogens through the wastewater based epidemiological model to timeously detect and recognize possible infections at a community level. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024
- Authors: Ngqwala, Balisa
- Date: 2024
- Subjects: COVID-19 (Disease) , SARS-CoV-2 disease , SARS coronavirus 2 disease
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29888 , vital:79184
- Description: The global health system and economy has been convulsed by the origin of Severe Acute respiratory Syndrome Coronavirus 2 SARS-CoV-2 infections which causes Coronavirus disease 2019 COVID-19. SARS-CoV-2 infections has become a recent global health concern, with drastic increase of illnesses and mortality cases. COVID- 19 originated in Wuhan, the capital of Hubei province in the People’s Republic of China, nonetheless, the diseases had spread to over 229 countries to date. COVID-19 clinical spectrum varies from mild fulminant pneumonia with acute respiratory distress to asymptomatic or mild respiratory infection or multi-organ failure resulting in death. Over 691 million cases with approximately 6.9 million fatalities have been recorded due to COVID-19 globally. The main route of transmission of this disease is reported to be respiratory droplets from an infected individual. However, previous studies demonstrate the presence of the virus in faces and urine as SARS-CoV-2 RNA fragments have been detected in wastewater and river waters around the world. The focal aim of this study was to profile and compare the incidence of SARS-COV-2 genomes in wastewater samples obtained from wastewater treatment facilities located in typical urban and peri-urban communities within the Buffalo City Municipality in the Eastern Cape Province, South Africa. Raw wastewater (influent) samples were collected by the grab sampling technique on a weekly basis for a period of 12 months sampling regime. Ribonucleic Acids were extracted from the collected wastewater WW samples, using the commercial QIAGEN Powersoil Total RNA Extraction kit, following the manufacturer’s guideline. The extracted RNA samples were further profiled for the presence and quantity of SARS-COV-2 genomes from the collected wastewate samples by Quantitative Real Time Polymerase Chain Reaction qRT-PCR technique. The findings of this study revealed the prevalence of SARS-COV-2 genomes from the raw wastewater samples across the urban and peri-urban study sites with the concentrations that ranged from 0.22 × 103 to 17.60 × 103 genome copies per millilitre GC/mL. Furthermore, various environmental matrices were utilized in the present study to estimate the potential health risk to plant operators associated with the exposure toSARS-CoV-2 viral particles using the quantitative microbiological risk assessment QMRA model. Different exposure scenarios were employed for the QMRA model and the findings indicate a probability of infection ranging from 0.93 percent to 37.81 percent across the study sites. Overall, the findings obtained in the current study highlight the bothersome concerns that reveal sewage systems as a transmission pathway for the dissemination of SARS-CoV-2 genomes in the environment. Therefore, this study accentuates the need for continued surveillance and constant environmental monitoring of SARS-CoV-2 other microbial pathogens through the wastewater based epidemiological model to timeously detect and recognize possible infections at a community level. , Thesis (MSci) -- Faculty of Science and Agriculture, 2024
- Full Text:
- Date Issued: 2024
Assessing the impact of access to climate services on smallholder farmers cropping decisions and household food security in Elundini Municipality, Eastern Cape province
- Authors: Nocezo, Yanga-Inkosi
- Date: 2023-11
- Subjects: Food security -- Climatic factors , Vegetation and climate , Crops and climate
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28882 , vital:75366
- Description: Climate variability has significant implications for crop production and overall food security. Climate services which provide tailored and localised climate information have the potential to enhance farmers understanding of climate patterns and support informed decision making. The purpose of the study was to assess the impact of climate services on smallholder farmers cropping decisions and household food security. The study adopted a cross sectional household survey on 217 smallholder crop farming households from Elundini Municipality. Structured questionnaires and face to face interviews were used to collect the required data from the farmers. Descriptive analysis was used to identify the types of climate service accessed by smallholder crop farmers in the study area. The probit model was used to examine factors influencing smallholder crop farmers access to specific climate services. The household dietary diversity score was used to measure household food security among smallholder crop farmers. The propensity score matching model was used to assess the impact of accessing specific climate services on cropping decisions and household food security. The results indicated that most farmers 77 percent in the study area had access to climate services. The results further showed that many farmers had access to short term weather forecast 79 percent with very few accessing seasonal forecast 22 percent. The results also revealed that access to both short term weather and seasonal forecasts is positively influenced by ownership of mobile phones and access to extension services. Similarly access to short term weather forecasts is positively influenced by age monthly income ownership of radio timely climate information and perceiving that climate change has negative effects on crop production. Land size knowledge of climate change and climate services accuracy are positive and significant factors influencing access to seasonal forecasts. Most of the smallholder farming households in the study area had higher dietary diversity scores 66 percent. Moreover access to short term weather and seasonal forecasts has a positive and significant impact on cropping decisions and household dietary diversity scores. The study concludes that climate services improve cropping decisions and household food security among smallholder crop farmers in Elundini Municipality. The study recommends that there should be investments in awareness programmes that will educate farmers about the importance of climate services and how to acquire and interpret both weather and seasonal forecasts. Stakeholders interested in improving smallholder farmers access to climate services should consider whether farmers own smart phones and have access to extension services arable land knowledge of climate change and if the climate services are accurate for smallholder farmers. In addition to improve crop production and household food security in the face of climate change access to climate services by smallholder farmers should be considered. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-11
- Authors: Nocezo, Yanga-Inkosi
- Date: 2023-11
- Subjects: Food security -- Climatic factors , Vegetation and climate , Crops and climate
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28882 , vital:75366
- Description: Climate variability has significant implications for crop production and overall food security. Climate services which provide tailored and localised climate information have the potential to enhance farmers understanding of climate patterns and support informed decision making. The purpose of the study was to assess the impact of climate services on smallholder farmers cropping decisions and household food security. The study adopted a cross sectional household survey on 217 smallholder crop farming households from Elundini Municipality. Structured questionnaires and face to face interviews were used to collect the required data from the farmers. Descriptive analysis was used to identify the types of climate service accessed by smallholder crop farmers in the study area. The probit model was used to examine factors influencing smallholder crop farmers access to specific climate services. The household dietary diversity score was used to measure household food security among smallholder crop farmers. The propensity score matching model was used to assess the impact of accessing specific climate services on cropping decisions and household food security. The results indicated that most farmers 77 percent in the study area had access to climate services. The results further showed that many farmers had access to short term weather forecast 79 percent with very few accessing seasonal forecast 22 percent. The results also revealed that access to both short term weather and seasonal forecasts is positively influenced by ownership of mobile phones and access to extension services. Similarly access to short term weather forecasts is positively influenced by age monthly income ownership of radio timely climate information and perceiving that climate change has negative effects on crop production. Land size knowledge of climate change and climate services accuracy are positive and significant factors influencing access to seasonal forecasts. Most of the smallholder farming households in the study area had higher dietary diversity scores 66 percent. Moreover access to short term weather and seasonal forecasts has a positive and significant impact on cropping decisions and household dietary diversity scores. The study concludes that climate services improve cropping decisions and household food security among smallholder crop farmers in Elundini Municipality. The study recommends that there should be investments in awareness programmes that will educate farmers about the importance of climate services and how to acquire and interpret both weather and seasonal forecasts. Stakeholders interested in improving smallholder farmers access to climate services should consider whether farmers own smart phones and have access to extension services arable land knowledge of climate change and if the climate services are accurate for smallholder farmers. In addition to improve crop production and household food security in the face of climate change access to climate services by smallholder farmers should be considered. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-11
Assessing the invasive status of the Oenothera species (evening primroses) in South Africa
- Authors: Scott, Zimbini
- Date: 2023-10
- Subjects: Evening primrose , Invasive plants -- Biological control -- South Africa , Ecological assessment (Biology)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28414 , vital:74321
- Description: Oenothera species (Myrtales: Onagraceae), commonly known as evening primroses, were introduced to South Africa for various purposes, where they established alien populations and expanded their distribution nationwide. Although some of these species are listed as emerging invaders in South Africa, their invasive status is currently unclear. This study assessed the invasive status of eight Oenothera species listed as emerging invaders in South Africa, namely, O. biennis, O. glazioviana, O. laciniata, O. indecora, O. stricta, O. jamesii and O. rosea. The study also focused on the biotic interactions of Oenothera with native arthropod species to assess any potential ecological impacts. The distribution of the eight Oenothera species was mapped using available occurrence records from sources such as the SAPIA database, herbarium records, and BRAHMS database. Additional records were collected by conducting field surveys in KwaZulu- Natal and Eastern Cape provinces. The distribution of these species was mapped using QGIS. Most Oenothera species were found in the Eastern Cape, KwaZulu-Natal, Gauteng, Free State, Mpumalanga and Western Cape provinces, while North-West, Northern Cape, and Limpopo provinces had fewer species. The grassland, savanna and fynbos biomes had more Oenothera species than other biomes in South Africa. The results indicated that O. biennis, O. glaziviana, and O. rosea are spreading at a preceding rate. In South Africa, the species flower predominantly in the spring and summer seasons. Species distribution modelling was conducted using Maxent to identify climatically suitable areas for establishing evening primrose populations. Species distribution models results show that the climatically suitable areas are concentrated in the central, eastern, and south-western regions of South Africa. The most considerable climatic variables contributing to the distribution of most Oenothera species were the annual mean temperature and precipitation during the driest month. To evaluate biotic interactions between native arthropods and Oenothera species and assess the potential ecological impacts, arthropods were collected from two Oenothera species (O. biennis and O. glazioviana) in different localities (only in Eastern Cape: East London and Fort Beaufort). The arthropods collected were identified, and diversity indices were calculated to determine the diversity of native arthropods collected in sites where these species are present. The overall number of individual arthropods collected was 768, belonging to six orders. These arthropod species belong to three feeding guilds: herbivores, predators, and palynivores. The ANOVA results showed that these species statistically differ in diversity for all the diversity indices. Overall, there were significant interactions between the arthropods’ orders and their feeding guilds. Lastly, the risk analysis framework assessed the potential for managing and listing two species (O. biennis and O. rosea) in the NEM: BA A&IS list. After considering all the likelihood elements, environmental, socioeconomic, and potential impacts, the risks posed by Oenothera biennis in South Africa were found to be high. The recommendation of this analysis suggests that O. biennis and O. rosea species be listed as category 1b in the NEMBA A & IS regulations list. The results of this study indicate that these congeners experience ecological differences, resulting in their varied distribution and invasion. Furthermore, they offer new insights regarding the geographical patterns and potential distribution of Oenothera species in South Africa. Moreover, it also provides recommendations for the management of the species in the South African context. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-10
- Authors: Scott, Zimbini
- Date: 2023-10
- Subjects: Evening primrose , Invasive plants -- Biological control -- South Africa , Ecological assessment (Biology)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28414 , vital:74321
- Description: Oenothera species (Myrtales: Onagraceae), commonly known as evening primroses, were introduced to South Africa for various purposes, where they established alien populations and expanded their distribution nationwide. Although some of these species are listed as emerging invaders in South Africa, their invasive status is currently unclear. This study assessed the invasive status of eight Oenothera species listed as emerging invaders in South Africa, namely, O. biennis, O. glazioviana, O. laciniata, O. indecora, O. stricta, O. jamesii and O. rosea. The study also focused on the biotic interactions of Oenothera with native arthropod species to assess any potential ecological impacts. The distribution of the eight Oenothera species was mapped using available occurrence records from sources such as the SAPIA database, herbarium records, and BRAHMS database. Additional records were collected by conducting field surveys in KwaZulu- Natal and Eastern Cape provinces. The distribution of these species was mapped using QGIS. Most Oenothera species were found in the Eastern Cape, KwaZulu-Natal, Gauteng, Free State, Mpumalanga and Western Cape provinces, while North-West, Northern Cape, and Limpopo provinces had fewer species. The grassland, savanna and fynbos biomes had more Oenothera species than other biomes in South Africa. The results indicated that O. biennis, O. glaziviana, and O. rosea are spreading at a preceding rate. In South Africa, the species flower predominantly in the spring and summer seasons. Species distribution modelling was conducted using Maxent to identify climatically suitable areas for establishing evening primrose populations. Species distribution models results show that the climatically suitable areas are concentrated in the central, eastern, and south-western regions of South Africa. The most considerable climatic variables contributing to the distribution of most Oenothera species were the annual mean temperature and precipitation during the driest month. To evaluate biotic interactions between native arthropods and Oenothera species and assess the potential ecological impacts, arthropods were collected from two Oenothera species (O. biennis and O. glazioviana) in different localities (only in Eastern Cape: East London and Fort Beaufort). The arthropods collected were identified, and diversity indices were calculated to determine the diversity of native arthropods collected in sites where these species are present. The overall number of individual arthropods collected was 768, belonging to six orders. These arthropod species belong to three feeding guilds: herbivores, predators, and palynivores. The ANOVA results showed that these species statistically differ in diversity for all the diversity indices. Overall, there were significant interactions between the arthropods’ orders and their feeding guilds. Lastly, the risk analysis framework assessed the potential for managing and listing two species (O. biennis and O. rosea) in the NEM: BA A&IS list. After considering all the likelihood elements, environmental, socioeconomic, and potential impacts, the risks posed by Oenothera biennis in South Africa were found to be high. The recommendation of this analysis suggests that O. biennis and O. rosea species be listed as category 1b in the NEMBA A & IS regulations list. The results of this study indicate that these congeners experience ecological differences, resulting in their varied distribution and invasion. Furthermore, they offer new insights regarding the geographical patterns and potential distribution of Oenothera species in South Africa. Moreover, it also provides recommendations for the management of the species in the South African context. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-10
Tourism and economic growth in the Republics of Botswana and Madagascar: an empirical investigation of causal links
- Authors: Masvingise, Kudzai
- Date: 2023-09
- Subjects: Tourism -- Botswana , Economic development -- Botswana , Econometric models
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28334 , vital:74267
- Description: This study investigated the Granger causality of tourism and economic growth in the Republics of Botswana and Madagascar during the period 1995 2019. The study was inspired by speculation regarding the influence of tourism on the economic growth of the two countries, given that the literature cautions that the relationship is not always direct and obvious, but rather depends on the country and changes over time. The ARDL-bounds F-test was used to test for co-integration and for Granger causality, with the ECM-based multivariate Granger-causality test used. The results confirm that tourism and economic growth have a prevailing stable, long-run co-integration in both countries, with a unidirectional causation, in that tourism is propelled by economic growth. These findings support the growth-led tourism GDP TOR hypothesis for both countries, and do not corroborate the popular tourism-led growth TPR GDP hypothesis. The study findings imply that both countries’ rich natural resources are insufficient to propel tourism growth and drive GDP in the absence of a supportive economic environment. The study therefore recommends that investment and policy efforts in Botswana and Madagascar focus more on overall economic development than at tourism per se. This would create an environment conducive for attracting and retaining visitors to these countries, and thus boost tourism. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-09
- Authors: Masvingise, Kudzai
- Date: 2023-09
- Subjects: Tourism -- Botswana , Economic development -- Botswana , Econometric models
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28334 , vital:74267
- Description: This study investigated the Granger causality of tourism and economic growth in the Republics of Botswana and Madagascar during the period 1995 2019. The study was inspired by speculation regarding the influence of tourism on the economic growth of the two countries, given that the literature cautions that the relationship is not always direct and obvious, but rather depends on the country and changes over time. The ARDL-bounds F-test was used to test for co-integration and for Granger causality, with the ECM-based multivariate Granger-causality test used. The results confirm that tourism and economic growth have a prevailing stable, long-run co-integration in both countries, with a unidirectional causation, in that tourism is propelled by economic growth. These findings support the growth-led tourism GDP TOR hypothesis for both countries, and do not corroborate the popular tourism-led growth TPR GDP hypothesis. The study findings imply that both countries’ rich natural resources are insufficient to propel tourism growth and drive GDP in the absence of a supportive economic environment. The study therefore recommends that investment and policy efforts in Botswana and Madagascar focus more on overall economic development than at tourism per se. This would create an environment conducive for attracting and retaining visitors to these countries, and thus boost tourism. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-09
Developing logit calibration model for wildfire smoke characterization based on sentinel-2 multispectral data and machine learning techniques
- Authors: Sali, Athule
- Date: 2023-07
- Subjects: Wildfires -- Prevention and control -- Contracting out , Smoke plumes , Remote-sensing images
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28467 , vital:74338
- Description: Wildfires are complicated incidents that arise as results of both natural causes and anthropological activities. They have long been regarded as the most devastating phenomena globally. Wildfires are considered a powerful natural factor which has detrimental effect on the global environment. This study was aimed at developing logit calibration models for wildfire smoke prediction based on Sentinel-2 multispectral data and machine learning techniques. Remotely sensed data, in the form of the Sentinel-2 imagery, was used as the base from which wildfire smoke plumes were spectrally characterized and distinguished from clouds and flame using endmember selection. The Smoke Detection Index (SDI) was generated to detect the relative abundance of smoke from the imagery. The Cloud Detection Index (CDI) was also generated from Sentinel-2 imagery to detect the relative abundance of clouds. The bi-level thresholding technique was also used to characterize wildfire smoke from the imagery. The logit models were developed through multilayer perceptron (MLP) neural network to predict wildfire smoke plumes. The Relative Operator Characteristic - Area Under the Curve (ROC-AUC) metrics was used to evaluate the logit models performance. The spectral signature pattern from endmembers revealed that wildfire smoke behaves different across Sentinel-2 multispectral channels with shortwave 1 channel (SWIR-1) exhibiting the highest radiance value. The signature patterns from endmember selection also revealed the distinctive spectral characterization of smoke from those of clouds. The findings showed that whilst smoke exhibited high radiance value on SWIR-1 channel, clouds exhibited high radiance value in the near infrared (NIR), signifying that smoke and cloud are spectrally separatable in the NIR. The smoke-containing pixels from bi-level thresholding were characterized by SDI values that ranged between 0.089 and 0.561. Suggesting that pixels associated with wildfire smoke are limited to this range of values. The logit models developed showed that smoke is predicted in SWIR-2. The ROC-AUC value obtained by this model was 0.77. The Implications emerging from the ROC-AUC results revealed that MLP model employed on the SWIR-2 band present a viable and accurate prediction of wildfire smoke plume. The findings of this study suggest that wildfire smoke is efficiently predicted at the shortwave channels of the electromagnetic spectrum. The wildfire smoke can be spectrally distinguished from cloud in the near infrared channel. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-07
- Authors: Sali, Athule
- Date: 2023-07
- Subjects: Wildfires -- Prevention and control -- Contracting out , Smoke plumes , Remote-sensing images
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28467 , vital:74338
- Description: Wildfires are complicated incidents that arise as results of both natural causes and anthropological activities. They have long been regarded as the most devastating phenomena globally. Wildfires are considered a powerful natural factor which has detrimental effect on the global environment. This study was aimed at developing logit calibration models for wildfire smoke prediction based on Sentinel-2 multispectral data and machine learning techniques. Remotely sensed data, in the form of the Sentinel-2 imagery, was used as the base from which wildfire smoke plumes were spectrally characterized and distinguished from clouds and flame using endmember selection. The Smoke Detection Index (SDI) was generated to detect the relative abundance of smoke from the imagery. The Cloud Detection Index (CDI) was also generated from Sentinel-2 imagery to detect the relative abundance of clouds. The bi-level thresholding technique was also used to characterize wildfire smoke from the imagery. The logit models were developed through multilayer perceptron (MLP) neural network to predict wildfire smoke plumes. The Relative Operator Characteristic - Area Under the Curve (ROC-AUC) metrics was used to evaluate the logit models performance. The spectral signature pattern from endmembers revealed that wildfire smoke behaves different across Sentinel-2 multispectral channels with shortwave 1 channel (SWIR-1) exhibiting the highest radiance value. The signature patterns from endmember selection also revealed the distinctive spectral characterization of smoke from those of clouds. The findings showed that whilst smoke exhibited high radiance value on SWIR-1 channel, clouds exhibited high radiance value in the near infrared (NIR), signifying that smoke and cloud are spectrally separatable in the NIR. The smoke-containing pixels from bi-level thresholding were characterized by SDI values that ranged between 0.089 and 0.561. Suggesting that pixels associated with wildfire smoke are limited to this range of values. The logit models developed showed that smoke is predicted in SWIR-2. The ROC-AUC value obtained by this model was 0.77. The Implications emerging from the ROC-AUC results revealed that MLP model employed on the SWIR-2 band present a viable and accurate prediction of wildfire smoke plume. The findings of this study suggest that wildfire smoke is efficiently predicted at the shortwave channels of the electromagnetic spectrum. The wildfire smoke can be spectrally distinguished from cloud in the near infrared channel. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-07
Exploring the involvement of the SARS-CoV-2 Replicase in the synthesis of polyamines and heat shock proteins
- Authors: Mthembu,Yamkela
- Date: 2023-07
- Subjects: Post COVID-19 condition (Disease) , COVID-19 (Disease) , Polyamines in the body
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:74275
- Description: A disease named COVID-19 almost destroyed the human population. It is caused by the SARS CoV 2 virus which emerged in 2019 and rapidly spread worldwide forcing all countries to shut down. This virus uses non-structural proteins to complete its invasion and development inside the host. The non-structural protein 2 NSP2 defined as the RNA binding protein involved in coronavirus genome replication and decreases the human immune response is key for this virus’s development and invasion. It is believed that the NSP2 associate themselves with polyamines and heat shock proteins inside the host cell, to proceed with the viral development and this study aimed to investigate how SARS CoV 2 virus key non-structural proteins NSP2 utilizes polyamines and heat shock proteins using the molecular docking approach and molecular dynamics MD. In this present study a docking approach was used. The dockings were done on ClusPro, and analysis was done on Discovery Studio, chimera, and PyMOL. One of the enzymes that are involved in the regulation of polyamine biosynthesis, adenosylmethionine decarboxylase AdoMetDC was used in investigating the polyamine binding to the viral NSP2, and major heat shock proteins HSPs HSP40, HSP70, and HSP90 were used in the investigation of the binding of HSPs to viral non-structural proteins NSP2. The results obtained show that 32 interactions were formed when docking heat shock protein 40 HSP40 with the SARS CoV 2 NSP2, but the area that has the highest interactions was from amino acid Ala554 to His557. Asp553 plays a very crucial role in this interaction forming six interactions. Heat shock protein 70 produced about 28 interactions when docked with the SARS CoV 2 NSP2. But the section with the most bonds was from position 550 to 560 of the ligand. Human heat shock protein 90 HSP90 formed 19 interactions when docked with the SARS CoV 2 viral NSP2. MD revealed Arg458, Asn508, Met297, Arg301 and Tr417 active residues. And pharmacophore modeling indicated zinc inhibitors as crucial for inhibiting this virus. Enough interactions were produced with ideal bonds lengths, and it can be said that the functioning of the SARS CoV2 viral non-structural proteins functioning majorly depends on the presence of the heat shock proteins at hand for proper formation and depends on polyamines for complete development and correct functioning. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-07
- Authors: Mthembu,Yamkela
- Date: 2023-07
- Subjects: Post COVID-19 condition (Disease) , COVID-19 (Disease) , Polyamines in the body
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/${Handle} , vital:74275
- Description: A disease named COVID-19 almost destroyed the human population. It is caused by the SARS CoV 2 virus which emerged in 2019 and rapidly spread worldwide forcing all countries to shut down. This virus uses non-structural proteins to complete its invasion and development inside the host. The non-structural protein 2 NSP2 defined as the RNA binding protein involved in coronavirus genome replication and decreases the human immune response is key for this virus’s development and invasion. It is believed that the NSP2 associate themselves with polyamines and heat shock proteins inside the host cell, to proceed with the viral development and this study aimed to investigate how SARS CoV 2 virus key non-structural proteins NSP2 utilizes polyamines and heat shock proteins using the molecular docking approach and molecular dynamics MD. In this present study a docking approach was used. The dockings were done on ClusPro, and analysis was done on Discovery Studio, chimera, and PyMOL. One of the enzymes that are involved in the regulation of polyamine biosynthesis, adenosylmethionine decarboxylase AdoMetDC was used in investigating the polyamine binding to the viral NSP2, and major heat shock proteins HSPs HSP40, HSP70, and HSP90 were used in the investigation of the binding of HSPs to viral non-structural proteins NSP2. The results obtained show that 32 interactions were formed when docking heat shock protein 40 HSP40 with the SARS CoV 2 NSP2, but the area that has the highest interactions was from amino acid Ala554 to His557. Asp553 plays a very crucial role in this interaction forming six interactions. Heat shock protein 70 produced about 28 interactions when docked with the SARS CoV 2 NSP2. But the section with the most bonds was from position 550 to 560 of the ligand. Human heat shock protein 90 HSP90 formed 19 interactions when docked with the SARS CoV 2 viral NSP2. MD revealed Arg458, Asn508, Met297, Arg301 and Tr417 active residues. And pharmacophore modeling indicated zinc inhibitors as crucial for inhibiting this virus. Enough interactions were produced with ideal bonds lengths, and it can be said that the functioning of the SARS CoV2 viral non-structural proteins functioning majorly depends on the presence of the heat shock proteins at hand for proper formation and depends on polyamines for complete development and correct functioning. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-07
Knowledge, awareness, and molecular epidemiology of fasciolosis in dairy cattle slaughtered in three commercial abattoirs in Eastern Cape Province, South Africa
- Authors: Mpisana, Zuko
- Date: 2023-06
- Subjects: Farm management -- South Africa -- Eastern Cape , Dairy cattle -- South Africa -- Eastern Cape , Fascioliasis
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28173 , vital:73792
- Description: Flukes and snail-borne diseases present significant challenges to livestock production, particularly impacting the dairy industry in the Eastern Cape Province, South Africa. Despite the challenges faced by the dairy sector, the level of knowledge and awareness among dairy farm personnel regarding the prevalence of bovine fasciolosis is unknown in Eastern Cape Province. Additionally, the genomic sequence of Fasciola spp. in dairy cattle slaughtered under abattoir conditions remains undisclosed. The primary objective of the titled study is to evaluate the knowledge, awareness, and molecular epidemiology of fasciolosis in dairy cattle slaughtered in three commercial abattoirs in the Eastern Cape province of South Africa. A structured questionnaire was prepared and randomly administered to 152 dairy farm personnel to investigate the knowledge and awareness of the aetiology, risk factors, and clinical signs of bovine fasciolosis among dairy farm personnel in the Eastern Cape Province, South Africa. A higher proportion of respondents from coastal regions were knowledgeable about the aetiology P equals 0.001 and the intermediate host P equals 0.000 of fasciolosis than those from the inland farms. A higher proportion of dairy farm personnel were not knowledgeable about the clinical signs of fasciolosis P equals 0.000 and the zoonotic potential P equals 0.001 of the disease. All farm personnel knew that season P 0.001 is a risk factor associated with snail-borne disease and occur throughout the year. However, the majority 63.2 percent of farm personnel agreed that fasciolosis was more prevalent in the summer followed by spring 27.6 percent, autumn 4.7 percent and winter 4.7 percent. Experiment 2 examined the body condition scores, fluke intensity, liver pathology, and carcass quality of various dairy cattle genotypes affected by Fasciola spp. infection, within three high-capacity abattoirs located in the Eastern Cape Province, South Africa. Milder infections were significantly noted to occur at a higher rate P 0.05 in Cross-bred cattle 46.9 percent followed by Holstein Friesian 39.5 percent and Jersey 30.9 percent cattle. Conversely, moderate infections were more prevalent P 0.05 among Jersey cattle 28.0 percent followed by Holstein Friesian 15.4 percent and Cross bred 1.9 percent cattle. Severe infections were more frequent P 0.05 in Holstein-Friesian 45.1 percent, followed by Jersey 41.9 percent and then Cross-bred 31.7 percent cattle. Heavy infections were observed in cattle with poor body condition scores in CA3. Mild infections were observed more in cattle with moderate body condition scores in CA3 and CA1 and less in CA2. Chapter 5 compared the detection rate of Fasciola infections using four different methods real-time quantitative polymerase chain reaction qPCR faecal sedimentation, antibody enzyme linked immunosorbent assay Ab ELISA and post-mortem liver examination among naturally infected cattle slaughtered at the abattoirs in the Eastern Cape Province, South Africa. A total of 145 slaughter cattle were screened for Fasciola infestation by liver examination, and corresponding samples from individual animals were analysed in the laboratory using Ab ELISA faecal sedimentation, and qPCR. The detection rate by liver inspection gold standard was significantly P 0.0001 higher than that by sedimentation and Ab ELISA but not significantly P 0.05 different from that by qPCR P equals 0.198. Post-mortem liver examination 94.5 percent and qPCR 90.4 percent had higher detection rate compared to Ab ELISA 22.6 percent and sedimentation 3.53 percent, respectively. The agreement between Ab ELISA and sedimentation was poor to slight kappa equals to minus 0.09 and with qPCR it was 0.008. The fourth experiment investigated genomic sequence of Fasciola spp. from faecal sample of slaughtered dairy cattle in Eastern Cape Province South Africa. Sequential and phylogenetic analyses were conducted to detect the presence of Fasciola spp. from the faecal samples obtained at the high throughput abattoirs. Fasciola hepatica and F. gigantica ITS 2 sequences were obtained by amplifying the 364 bp and 300 bp genes, respectively using species specific conventional PCR assays followed by cloning and sequencing. The phylogenetic tree revealed the presence of Fasciola hepatica as the only aetiological agent infecting dairy cattle in the Eastern Cape Province South Africa. The study concluded that dairy farm personnel lacks knowledge about zoonotic potentials, aetiological agents of fasciolosis high fluke intensity and its impact on carcasses sensitivity and suitability of detection methods. The study observed Fasciola hepatica as the only trematode spp. present in Eastern Cape Province South Africa. , Thesis (PhD) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-06
- Authors: Mpisana, Zuko
- Date: 2023-06
- Subjects: Farm management -- South Africa -- Eastern Cape , Dairy cattle -- South Africa -- Eastern Cape , Fascioliasis
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/28173 , vital:73792
- Description: Flukes and snail-borne diseases present significant challenges to livestock production, particularly impacting the dairy industry in the Eastern Cape Province, South Africa. Despite the challenges faced by the dairy sector, the level of knowledge and awareness among dairy farm personnel regarding the prevalence of bovine fasciolosis is unknown in Eastern Cape Province. Additionally, the genomic sequence of Fasciola spp. in dairy cattle slaughtered under abattoir conditions remains undisclosed. The primary objective of the titled study is to evaluate the knowledge, awareness, and molecular epidemiology of fasciolosis in dairy cattle slaughtered in three commercial abattoirs in the Eastern Cape province of South Africa. A structured questionnaire was prepared and randomly administered to 152 dairy farm personnel to investigate the knowledge and awareness of the aetiology, risk factors, and clinical signs of bovine fasciolosis among dairy farm personnel in the Eastern Cape Province, South Africa. A higher proportion of respondents from coastal regions were knowledgeable about the aetiology P equals 0.001 and the intermediate host P equals 0.000 of fasciolosis than those from the inland farms. A higher proportion of dairy farm personnel were not knowledgeable about the clinical signs of fasciolosis P equals 0.000 and the zoonotic potential P equals 0.001 of the disease. All farm personnel knew that season P 0.001 is a risk factor associated with snail-borne disease and occur throughout the year. However, the majority 63.2 percent of farm personnel agreed that fasciolosis was more prevalent in the summer followed by spring 27.6 percent, autumn 4.7 percent and winter 4.7 percent. Experiment 2 examined the body condition scores, fluke intensity, liver pathology, and carcass quality of various dairy cattle genotypes affected by Fasciola spp. infection, within three high-capacity abattoirs located in the Eastern Cape Province, South Africa. Milder infections were significantly noted to occur at a higher rate P 0.05 in Cross-bred cattle 46.9 percent followed by Holstein Friesian 39.5 percent and Jersey 30.9 percent cattle. Conversely, moderate infections were more prevalent P 0.05 among Jersey cattle 28.0 percent followed by Holstein Friesian 15.4 percent and Cross bred 1.9 percent cattle. Severe infections were more frequent P 0.05 in Holstein-Friesian 45.1 percent, followed by Jersey 41.9 percent and then Cross-bred 31.7 percent cattle. Heavy infections were observed in cattle with poor body condition scores in CA3. Mild infections were observed more in cattle with moderate body condition scores in CA3 and CA1 and less in CA2. Chapter 5 compared the detection rate of Fasciola infections using four different methods real-time quantitative polymerase chain reaction qPCR faecal sedimentation, antibody enzyme linked immunosorbent assay Ab ELISA and post-mortem liver examination among naturally infected cattle slaughtered at the abattoirs in the Eastern Cape Province, South Africa. A total of 145 slaughter cattle were screened for Fasciola infestation by liver examination, and corresponding samples from individual animals were analysed in the laboratory using Ab ELISA faecal sedimentation, and qPCR. The detection rate by liver inspection gold standard was significantly P 0.0001 higher than that by sedimentation and Ab ELISA but not significantly P 0.05 different from that by qPCR P equals 0.198. Post-mortem liver examination 94.5 percent and qPCR 90.4 percent had higher detection rate compared to Ab ELISA 22.6 percent and sedimentation 3.53 percent, respectively. The agreement between Ab ELISA and sedimentation was poor to slight kappa equals to minus 0.09 and with qPCR it was 0.008. The fourth experiment investigated genomic sequence of Fasciola spp. from faecal sample of slaughtered dairy cattle in Eastern Cape Province South Africa. Sequential and phylogenetic analyses were conducted to detect the presence of Fasciola spp. from the faecal samples obtained at the high throughput abattoirs. Fasciola hepatica and F. gigantica ITS 2 sequences were obtained by amplifying the 364 bp and 300 bp genes, respectively using species specific conventional PCR assays followed by cloning and sequencing. The phylogenetic tree revealed the presence of Fasciola hepatica as the only aetiological agent infecting dairy cattle in the Eastern Cape Province South Africa. The study concluded that dairy farm personnel lacks knowledge about zoonotic potentials, aetiological agents of fasciolosis high fluke intensity and its impact on carcasses sensitivity and suitability of detection methods. The study observed Fasciola hepatica as the only trematode spp. present in Eastern Cape Province South Africa. , Thesis (PhD) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-06
Effect of Nitrogen application , leaf age, and drying method on growth, yield and quality of sweet potato
- Joko, Lungisa Banathi https://orcid.org/0000-0002-6369-7146
- Authors: Joko, Lungisa Banathi https://orcid.org/0000-0002-6369-7146
- Date: 2023-05
- Subjects: Nitrogen in agriculture , Sweet potato leaves , Sweet potatoes -- Harvesting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28244 , vital:73957
- Description: Root crops, such as sweet potatoes, are important sources of carbohydrates in the pacific region where soils are generally of inferior quality. Sweet potato leaves are said to be more nutritious when compared with storage roots, therefore can be used as a source of nutrition by human beings. Sweet potatoes like other vegetables are perishable and therefore they need to be processed in order to increase storage life. The shelf life of perishable vegetables can be increased by the use of drying methods. This brings an opportunity area for research to realize the full potential of sweet potatoes. Sweet potatoes can be developed as a sustainable crop for diverse nutritionally enhanced and value-added food products to promote human nutrition. Thus, the study sought to develop nitrogen level that could result in maximum yield of tubers while the green leaves are harvested for human consumption. The study also sought to find the best suitable drying method to extend the shelf life of orange-fleshed sweet potatoes OFSP leaves. The research was conducted at the University of Fort Hare glasshouse, Alice, in the Eastern Cape Province of South Africa. OFSP plants were grown at the UFH research farm, harvested and sorted according to their different age groups. The leaves were then taken to the glasshouse for the experiment to be conducted. The first experiment followed CRD 4x3 factorial replicated 3 times, with 4 levels of leaf age (upper, middle, lower, basal) and 3 levels of drying sun, shade, oven. The second experiment followed a RCBD replicated five times, with 4 levels of N 50 100 150, and 200 kgha randomly allocated. All the nutritional analysis was done based on the recommendations by the Association of Official Chemists A.O.A.C. Statistical analysis was done using SAS, Version 9.1. Where a significant difference was detected, variable means were separated using Fisher’s protected least significant difference p 0.05. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-05
- Authors: Joko, Lungisa Banathi https://orcid.org/0000-0002-6369-7146
- Date: 2023-05
- Subjects: Nitrogen in agriculture , Sweet potato leaves , Sweet potatoes -- Harvesting
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28244 , vital:73957
- Description: Root crops, such as sweet potatoes, are important sources of carbohydrates in the pacific region where soils are generally of inferior quality. Sweet potato leaves are said to be more nutritious when compared with storage roots, therefore can be used as a source of nutrition by human beings. Sweet potatoes like other vegetables are perishable and therefore they need to be processed in order to increase storage life. The shelf life of perishable vegetables can be increased by the use of drying methods. This brings an opportunity area for research to realize the full potential of sweet potatoes. Sweet potatoes can be developed as a sustainable crop for diverse nutritionally enhanced and value-added food products to promote human nutrition. Thus, the study sought to develop nitrogen level that could result in maximum yield of tubers while the green leaves are harvested for human consumption. The study also sought to find the best suitable drying method to extend the shelf life of orange-fleshed sweet potatoes OFSP leaves. The research was conducted at the University of Fort Hare glasshouse, Alice, in the Eastern Cape Province of South Africa. OFSP plants were grown at the UFH research farm, harvested and sorted according to their different age groups. The leaves were then taken to the glasshouse for the experiment to be conducted. The first experiment followed CRD 4x3 factorial replicated 3 times, with 4 levels of leaf age (upper, middle, lower, basal) and 3 levels of drying sun, shade, oven. The second experiment followed a RCBD replicated five times, with 4 levels of N 50 100 150, and 200 kgha randomly allocated. All the nutritional analysis was done based on the recommendations by the Association of Official Chemists A.O.A.C. Statistical analysis was done using SAS, Version 9.1. Where a significant difference was detected, variable means were separated using Fisher’s protected least significant difference p 0.05. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-05
Viability of government funded broiler production : lessons from Northern KwaZulu Natal, South Africa
- Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Date: 2023-04
- Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27843 , vital:69947
- Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Mdletshe, Sifiso Themba Clement https://orcid.org/0000-0002-2668-0193
- Date: 2023-04
- Subjects: Broilers (Chickens) -- Economic aspects , Broilers (Poultry) , Broilers (Chickens) -- Breeding
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27843 , vital:69947
- Description: Generally, rural areas continue to experience high poverty levels and low incomes, which seem to be occasioned by high unemployment rates, limited educational attainments, and devastating floods and droughts. This situation is further exacerbated by increase in crime rates, making livelihoods even more difficult. To mitigate such adverse situations, rural households employ diverse strategies, including maintaining community gardens, one-home-one-garden schemes, as well as livestock and poultry production. The most prevalent livelihood strategy in South Africa or KwaZulu-Natal is broiler production, since it needs less space and a short production cycle compared to other livestock or crop enterprises. At the same time, income is generated over a short period. Besides, the government of KwaZulu Natal has actively intervened in the sector as part of its broader poverty reduction strategy and farmer support programmes. In KwaZulu-Natal Province, the provincial government has been supporting broiler producers for many years. While substantial research work has been done in the province on livelihood strategies, including livestock production on a province-wide basis, there is no information about how successful the broiler production funded by the government has being. Broader concerns about production problems have not been assuaged based on systematic studies and evidence. It is this wise that this study was initiated. The objective is to assess the economic viability of government-funded small-scale broiler projects in the KwaZulu-Natal Province of South Africa and determine the implications for poverty reduction and food security. Data were collected from the government-funded small-scale broiler producers that are residing in Northern KwaZulu-Natal districts uThungulu, Zululand and uMkhanyakude. A total of 75 small-scale broiler projects 25 broiler projects in each district were selected by probability sampling procedure for the interviews. Questionnaires that combined both close-ended and open-ended questions were used to collect primary data, which include production and marketing, as well as the factors that influence the profitability of the small-scale broiler projects. After collection, data were captured and encoded on spreadsheets in Microsoft Excel and exported to Statistical Package for the Social Science (SPSS) software version 26 and STATA for analyses. Descriptive statistics applied include frequencies and means. In addition, a gross margin (GM) and gross profit margin (GPM) analysis were employed to assess the profitability of government-funded small-scale broiler projects. Both profitability and gross margin analyses were used as proxies for farmers’ motivation and incentives to participate in broiler production. Further analyses were conducted to determine the model that best explains the underlying relationships. Initially, the Multiple Linear Regression Model was applied to determine the factors influencing the profitability of government-funded small-scale broiler projects. The indication was that while positive profits were revealed, the system seemed to fall short of its potential. In light of that, it was decided to fit another model to estimate the technical efficiency of the system and gain an understanding of the causes of any inefficiency that might exist in the production system. In that regard, the one-step Stochastic Frontier Model was employed to show that the technical efficiency of broiler production systems in the project area was positively and significantly influenced by flock size, the quantity of feeds and labour costs, while medication played no role possibly because of weak extension coverage. An inefficiency model fitted as part of the one-step model suggested that age, gender and educational level were significant influencers of technical inefficiency, with the possibility that the older the farmers, the more technically inefficient the system possibly because of the strenuousness of commercial poultry production. In addition, it was found that the more educated the farmer, the less inefficient the farm, which conversely means that the system becomes more efficient as the farmer receives more education. The negative coefficient of the gender variable also implies that for farms managed by female farmers, the system was less inefficient, which is more technically efficient, and this can be explained by women’s propensity to be more gentle, caring and sensitive in managing the chickens than their male counterparts. Heteroskedasticity tests and corrections were conducted in the one-step estimation technique to show that variations in the inefficiency term (μ) and the stochastic error term were explained by age and educational level for the most part. Clearly, improvements in the broiler industry in KwaZulu-Natal will depend to a large extent on the knowledge and experience of the farmers and substantial enlargement of the flock size of adequately fed birds. Attention to these elements is expected to have important practical implications for sustainable broiler poultry development and food security in the project area, as well as locations possessing identical features and characteristics. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-04
Evaluation of spatial distribution and health risk of pesticide residues in the environmental matrices of buffalo river estuary and their removal using nanosponges and modified cyclodextrins
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Mdeni, Nonkululeko Landy
- Date: 2023-03
- Subjects: Chemicals , Hazardous substances , Dangerous chemicals
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27629 , vital:69321
- Description: The contamination of lotic ecosystems caused by agricultural, industrial, and anthropogenic activities has attracted the attention of researchers, authorities, and scientists because these waterbodies are of social and economic importance to human livelihoods. Pesticides and insecticides are a group of compounds that are toxic to pests and insects, respectively. Organophosphate pesticides (OPs) can be released into different environmental matrices through several sources including agricultural and urban runoff. They are one of the three main classes of synthetic organic pesticides that are used in agricultural sector and very often end up in other destinations than their target sites. In this study, four OPs, namely, ronnel, malathion, parathion and Durban were investigated. The Buffalo River Estuary, located in East London, is one of most popular areas and the river is a major source of raw water abstraction for three municipalities in the Eastern Cape Province, South Africa. Sediment samples were collected from six points in the estuary and soil samples were taken from a nearby dumpsite in winter and spring seasons of 2021. The physicochemical parameters of the samples including particle size, moisture content, oil and grease and organic carbon were determined. The samples were then extracted by ultra-sonication, the final extracts were analyzed using GC-μECD and the risk quotient (RQ) method was used to evaluate the risk of OP exposure to aquatic organisms. Polymer modified cyclodextrin (β-CD) for the removal of parathion in sediment and soil was synthesized and the morphology of the modified β-CD and vibrations of the synthesized material were determined using scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The limit of detection (LOD) and the limit of quantification (LOQ) of the OPs investigated were in the range of 0.09 to 2.99 and 0.274 to 9.06 μg/L, respectively. OPs gave a good recovery except for malathion, which had a recovery percentage lower than 70%. Calibration curves were plotted for the four OPs and were linear with relative standard deviations (RSD) ranging from 1.02 to 3.50, and correlation coefficients (R2) ranging from 0.9935 to 0.9972. The mean concentrations for sediments and soil in both seasons varied from 0.00231 to 63.8 μg/g in winter and from 0.0017 to 36.6 μg/g in spring, with malathion being the predominant congener and dursban being the least dominant in both seasons. In winter, the particle size percentages of the sediment and soil samples ranged from 34.4 to 79.4 percentage, 15.4 to 23.9 percentage and from 7.77 to 38.3 percentage for coarse, medium, and fine fractions, respectively. While in spring, the particle size for the course, medium and fine mesh fractions ranged from 37.4 to 74.6 percentage, 14.1 to 25.1 percentage and 12.4 to 35.0 percentage respectively; the percentage moisture content varied from 43.0 to 73.1 in winter, and from 57.1 to 63.4 in spring. In the soil samples, the physicochemical properties were lower in winter except for the n- hexane extractable material (HEM), which significantly decreased in spring from 2.6 to 1.63 mg/kg; while for sediments, the oil and grease ranged from 1.77 to 10.3 mg/kg in winter and from 1.63 to 4.28 mg/kg in spring. The risk quotient method was used to determine the risk of OP exposure to sediment-dwelling organisms and the results obtained indicated that the levels of OPs in this study, especially dursban, can pose a high risk to the organisms in sediments, with RQs higher than ten (˃10) in both winter and summer. The Pearson product-moment correlation showed that parathion had a weak correlation with every other variable except for malathion in winter, whereas in spring, parathion correlated very weakly with malathion; suggesting that products containing parathion are mostly used to control pests found in crops, such as corn and mosquitos, which are most active in the spring season. There was a very strong correlation between dursban and ronnel in spring and winter, implying that an increase in dursban concentration resulted in an increase in the concentration of ronnel. To determine the efficiency of the synthesized adsorbent CD-chitosan-alginate for the removal of Parathion from soil and sediment, different parameters such as concentration, time, pH and dose were varied. The adsorption capacity was found to be highest at pH 2 (99.19 percentage), when 3 mL of the adsorbent was used for 30 minutes. , Thesis (Msci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
Evaluation of water and sanitation challenges in informal settlements: a case study of Duncan Village, East London, South Africa
- Authors: Munyai, Khodani Keith
- Date: 2023-03
- Subjects: Squatter settlements , Water quality management , Sanitation, Rural
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27721 , vital:69396
- Description: Water and sanitation are basic human needs. It is also a constitutional right for all citizens in South Africa to have access to both water and sanitation. Supply of water and sanitation services in South Africa is characterised by both achievements and challenges. As informed by literature, in South Africa it is evident that water and sanitation still hold many challenges in poor communities, particularly in informal settlements. This study was conducted with the purpose of evaluating water and sanitation challenges in the informal settlements of Duncan Village and make recommendations, where applicable, to the local municipality for possible remedies. Despite the provision of water and sanitation by the Buffalo City Metro Municipality, the study reveals that there are serious water and sanitation challenges in Duncan Village. High water losses, illegal water connections, illegal sanitation connections causing sewer spillages, vandalism of both water and sanitation service infrastructure, and lack of operations and maintenance are identified as the key water and sanitation challenges. According to the findings, the causes of these challenges include the municipality's lack of proper planning for informal settlements; lack of visibility of municipal water and sanitation officials in informal settlements; lack of awareness; lack of public participation; overpopulation; lack of monitoring; and lack of operations and maintenance budget to help keep the provided facilities intact and usable. The study's key recommendations include intense involvement of the municipality and the ward councillors, ownership by the residents, monitoring of water and sanitation facilities, operations and maintenance, and formalising Duncan Village informal settlements. This was accomplished using questionnaires to gather, analyse, and interpret the collected data. The study targeted residents, ward councillors, and a municipal officer from the municipality's Water and Sanitation section as respondents , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
- Authors: Munyai, Khodani Keith
- Date: 2023-03
- Subjects: Squatter settlements , Water quality management , Sanitation, Rural
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27721 , vital:69396
- Description: Water and sanitation are basic human needs. It is also a constitutional right for all citizens in South Africa to have access to both water and sanitation. Supply of water and sanitation services in South Africa is characterised by both achievements and challenges. As informed by literature, in South Africa it is evident that water and sanitation still hold many challenges in poor communities, particularly in informal settlements. This study was conducted with the purpose of evaluating water and sanitation challenges in the informal settlements of Duncan Village and make recommendations, where applicable, to the local municipality for possible remedies. Despite the provision of water and sanitation by the Buffalo City Metro Municipality, the study reveals that there are serious water and sanitation challenges in Duncan Village. High water losses, illegal water connections, illegal sanitation connections causing sewer spillages, vandalism of both water and sanitation service infrastructure, and lack of operations and maintenance are identified as the key water and sanitation challenges. According to the findings, the causes of these challenges include the municipality's lack of proper planning for informal settlements; lack of visibility of municipal water and sanitation officials in informal settlements; lack of awareness; lack of public participation; overpopulation; lack of monitoring; and lack of operations and maintenance budget to help keep the provided facilities intact and usable. The study's key recommendations include intense involvement of the municipality and the ward councillors, ownership by the residents, monitoring of water and sanitation facilities, operations and maintenance, and formalising Duncan Village informal settlements. This was accomplished using questionnaires to gather, analyse, and interpret the collected data. The study targeted residents, ward councillors, and a municipal officer from the municipality's Water and Sanitation section as respondents , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-03
Design and development of mobile-based e-Marketing application for communal farmers in Eastern Cape. South Africa.
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-02
- Authors: Fatumo, Dare Ebenezer
- Date: 2023-02
- Subjects: Food security , Agriculture , Agriculture -- Technology transfer
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27511 , vital:67421
- Description: The application of Information and Communication Technologies (ICT) in agriculture can augment farmers' production capabilities, this is a perception for all farmers worldwide, but there are some in communal areas who may not be as exposed to ICT tools as their commercial counterparts in urban areas, especially in developed communities. Food security in any society is a vital measure that should always be treated with high priority since humankind's existence is based on food availability. One major challenge with farmers in communal areas has been the marketing of their farm produce effectively to avoid wastage, get more value, and bridge the gap between themselves and urban commercial farmers. This challenge includes food wastage, untimely information, and market accessibility due to distance restraint. ICT can beused to bring a functional platform to assist this challenge. In this context, communal farmers have a challenge. The aim of this research was to design and develop an easy-to-use mobilebased e-marketing application for marketing farm products for communal farmers in Alice community, South Africa. Before design and development, review of challenges of farmers on the reception and communication of sensitive information pertaining to food security. Effective communication of farm produce baseline information on awareness and adaptation of mobile ICT technology of communal farmers was investigated. A mixed method was used through reviews of literature and as well distribution of questionnaires to get an understanding of the present state of communal farmers’ marketing problems. Furthermore, a prototyping methodology was used in the development of the mobile-based application for this research. The result of this research demonstrated the need for communal farmers to market their farm products at their convenience. An easy-to-use mobile-based e-market application was then developed; the application is an android application that will assist communal farmers in marketing their farm products as soon as they are available to avoid food wastage. The application performance and evaluation assessment indicated that the tool would maximize farm productivity and profitability and, facilitate concise and effective access to the market, as well as eliminate the need for an intermediary. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023-02
Analyzing agricultural financing for resettled farmers in Zimbabwe: the case of targeted Command Agricultural program in Mutare District
- Mafirakurewa, Tariro https://orcid.org/0009-0000-6587-4524
- Authors: Mafirakurewa, Tariro https://orcid.org/0009-0000-6587-4524
- Date: 2023
- Subjects: Agricultural administration--Finance , Farmers -- Zimbabwe , Agriculture -- Economic aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28255 , vital:73985
- Description: Agriculture plays a paramount role in the economy of many countries including Zimbabwe where more than 70 percent of the population depends on agricultural activities for their livelihoods. Smallholder farmers’ access to agricultural credit is vital for the development and growth of Zimbabwe’s agricultural sector, hence agricultural financing is crucial in rural development. Despite the Government’s efforts to provide affordable agricultural credit services to its majority smallholder farmers’ participation is still meager. The aim of this study is to analyze agricultural financing for resettled farmers in Zimbabwe, with special focus on the command agricultural loans in the Mutare district. A multistage sampling technique was employed in this study. Firstly purposive selection of Manicaland province was carried out because it is endowed with the five natural farming regions found in Zimbabwe. The second stage involved a random selection of 4 out of 7 districts with favorable climatic conditions for maize production. Thirdly, the study also carried out a purposive selection of Mutare district among the four districts with favorable climatic conditions, given the time and financial constraints. The last stage involved the use of stratified sampling technique, where the sample was divided into two strata. Stratum 1 with A1 farmers and stratum two consisting of A2 farmers, and a random sample was selected from each stratum. The study involved 301 A1 farmers and 49 A2 farmers, making a total sample of 350 farmers used for this study. Double hurdle was employed to examine the factors influencing A1 and A2 farmers` participation in command agriculture loans in the study area. Multinomial logistic regression model was also applied to investigate the determinants of command agriculture loan repayment, while propensity score matching technique was used to examine the impacts of command agriculture loans on maize productivity and profitability of A1 and A2 farmers. The results revealed that family size, and distance from the market GMB positively influence farmers likelihood to participate in in the command agricultural loan. While family size, farmer type and distance from the market were proven to have a positive significant influence on the extent of participation in command agriculture. Also training on the command agriculture loan and gender were proven to have a negative signification influence on the extent of farmers` participation in command agriculture loan. The maximum likelihood estimates of the multinomial logistic regression revealed that age and output levels significantly influence resettled farmers` likelihood to partly pay their loans. Also, the likelihood estimates of the multinomial logistic regression showed that distance from the market and output levels have a positive influence on resettled farmers` likelihood of fully paying the command agriculture loan. Access to extension services to extension services was proven to negatively influence farmers` likelihood to fully pay the loan. The results also revealed that participating in command agriculture significantly impacted productivity at the 1 percent level, while it was not significant in the participants' profitability. The results show that participating in command agriculture increases productivity by 0.93 tonnes hectare. The study recommends the intensification of extension service supply to ensure that farmers are receiving relevant agricultural training, mainly on climate change adaptation strategies. This will help resettled farmers to adjust and adapt to their new farming environments and, in turn, have a positive impact on their production levels. Also, to improve farmers’ profitability the GMB selling price should be in American dollars USD and not paid in part RTGS and part USD, because the RTGS part is always outstripped by inflation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Mafirakurewa, Tariro https://orcid.org/0009-0000-6587-4524
- Date: 2023
- Subjects: Agricultural administration--Finance , Farmers -- Zimbabwe , Agriculture -- Economic aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28255 , vital:73985
- Description: Agriculture plays a paramount role in the economy of many countries including Zimbabwe where more than 70 percent of the population depends on agricultural activities for their livelihoods. Smallholder farmers’ access to agricultural credit is vital for the development and growth of Zimbabwe’s agricultural sector, hence agricultural financing is crucial in rural development. Despite the Government’s efforts to provide affordable agricultural credit services to its majority smallholder farmers’ participation is still meager. The aim of this study is to analyze agricultural financing for resettled farmers in Zimbabwe, with special focus on the command agricultural loans in the Mutare district. A multistage sampling technique was employed in this study. Firstly purposive selection of Manicaland province was carried out because it is endowed with the five natural farming regions found in Zimbabwe. The second stage involved a random selection of 4 out of 7 districts with favorable climatic conditions for maize production. Thirdly, the study also carried out a purposive selection of Mutare district among the four districts with favorable climatic conditions, given the time and financial constraints. The last stage involved the use of stratified sampling technique, where the sample was divided into two strata. Stratum 1 with A1 farmers and stratum two consisting of A2 farmers, and a random sample was selected from each stratum. The study involved 301 A1 farmers and 49 A2 farmers, making a total sample of 350 farmers used for this study. Double hurdle was employed to examine the factors influencing A1 and A2 farmers` participation in command agriculture loans in the study area. Multinomial logistic regression model was also applied to investigate the determinants of command agriculture loan repayment, while propensity score matching technique was used to examine the impacts of command agriculture loans on maize productivity and profitability of A1 and A2 farmers. The results revealed that family size, and distance from the market GMB positively influence farmers likelihood to participate in in the command agricultural loan. While family size, farmer type and distance from the market were proven to have a positive significant influence on the extent of participation in command agriculture. Also training on the command agriculture loan and gender were proven to have a negative signification influence on the extent of farmers` participation in command agriculture loan. The maximum likelihood estimates of the multinomial logistic regression revealed that age and output levels significantly influence resettled farmers` likelihood to partly pay their loans. Also, the likelihood estimates of the multinomial logistic regression showed that distance from the market and output levels have a positive influence on resettled farmers` likelihood of fully paying the command agriculture loan. Access to extension services to extension services was proven to negatively influence farmers` likelihood to fully pay the loan. The results also revealed that participating in command agriculture significantly impacted productivity at the 1 percent level, while it was not significant in the participants' profitability. The results show that participating in command agriculture increases productivity by 0.93 tonnes hectare. The study recommends the intensification of extension service supply to ensure that farmers are receiving relevant agricultural training, mainly on climate change adaptation strategies. This will help resettled farmers to adjust and adapt to their new farming environments and, in turn, have a positive impact on their production levels. Also, to improve farmers’ profitability the GMB selling price should be in American dollars USD and not paid in part RTGS and part USD, because the RTGS part is always outstripped by inflation. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
Crop production constraints and coping strategies of small-scale crop and maize farmers in Gcuwa, Mnquma Local Municipality, South Africa
- Manyenyeza, Akhona Wesley Siyavuya
- Authors: Manyenyeza, Akhona Wesley Siyavuya
- Date: 2023
- Subjects: Crop science , Agricultural productivity , Agriculture -- Economic aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29922 , vital:79191
- Description: Diverse biotic and abiotic constraints limit small-scale farmers' agricultural productivity in developing countries. However, small-scale farmers have developed coping and adaptive strategies to cope with some of these constraints, strengthening their resilience to various stresses. This study aimed to examine the constraints impeding maize production and identify coping strategies employed by small-scale crop farmers in Gcuwa, Mnquma Local Municipality, South Africa, to provide insights and recommendations for enhancing the sustainability and productivity of maize farming in this region. The researcher employed a descriptive survey design within a quantitative research approach to collect participant data. The researcher used a non-probability, purposive sampling method to select 120 household heads, that met the inclusion criteria to participate in the study. Results demonstrated that most small-scale farmers in this study were adults over 35 years old 90.83 percent, female 51.67 percent, single 44.17 percent, and owned 86.67 percent land they lived on. Constraints that inhibit small-scale farmers from producing sufficient crops for subsistence and selling excess were related to droughts, pests and insects, infertile soil and lack of infrastructure and finance. To cope with constraints, small-scale farmers borrow money from friends, family, neighbours, or loan sharks to survive difficult times. Others only cook simple foods, such as maize, and some get rid of their assets or livestock. They believe the government can offer better long-term support to implement adaptative strategies, such as supplying seeds and fertiliser at reasonable costs, and be responsible for offering regular training and information workshops on small-scale farming and climate change. Recommendations that flow form the study is that small-scale farmers should select crop varieties that are adapted to the specific climatic conditions of Gcuwa region and diversify their crops. Moreover, leaders in the community should facilitate the establishment of collaborative networks among local farmers to facilitate the exchange of knowledge, resources, and mutual assistance in times of adversity. It is further recommended that the Land Bank or ARC should assist small-scale farmers to construct comprehensive financial plans and that the local government should allow small-scale farmers to have input in meetings so that their needs can be heard and addressed and could start a project to provide small-scale farmers with water tanks or irrigation pipes. It is recommended that agriculture as a subject, should be made compulsory at schools as youth show no interest in farming and farmers. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Manyenyeza, Akhona Wesley Siyavuya
- Date: 2023
- Subjects: Crop science , Agricultural productivity , Agriculture -- Economic aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/29922 , vital:79191
- Description: Diverse biotic and abiotic constraints limit small-scale farmers' agricultural productivity in developing countries. However, small-scale farmers have developed coping and adaptive strategies to cope with some of these constraints, strengthening their resilience to various stresses. This study aimed to examine the constraints impeding maize production and identify coping strategies employed by small-scale crop farmers in Gcuwa, Mnquma Local Municipality, South Africa, to provide insights and recommendations for enhancing the sustainability and productivity of maize farming in this region. The researcher employed a descriptive survey design within a quantitative research approach to collect participant data. The researcher used a non-probability, purposive sampling method to select 120 household heads, that met the inclusion criteria to participate in the study. Results demonstrated that most small-scale farmers in this study were adults over 35 years old 90.83 percent, female 51.67 percent, single 44.17 percent, and owned 86.67 percent land they lived on. Constraints that inhibit small-scale farmers from producing sufficient crops for subsistence and selling excess were related to droughts, pests and insects, infertile soil and lack of infrastructure and finance. To cope with constraints, small-scale farmers borrow money from friends, family, neighbours, or loan sharks to survive difficult times. Others only cook simple foods, such as maize, and some get rid of their assets or livestock. They believe the government can offer better long-term support to implement adaptative strategies, such as supplying seeds and fertiliser at reasonable costs, and be responsible for offering regular training and information workshops on small-scale farming and climate change. Recommendations that flow form the study is that small-scale farmers should select crop varieties that are adapted to the specific climatic conditions of Gcuwa region and diversify their crops. Moreover, leaders in the community should facilitate the establishment of collaborative networks among local farmers to facilitate the exchange of knowledge, resources, and mutual assistance in times of adversity. It is further recommended that the Land Bank or ARC should assist small-scale farmers to construct comprehensive financial plans and that the local government should allow small-scale farmers to have input in meetings so that their needs can be heard and addressed and could start a project to provide small-scale farmers with water tanks or irrigation pipes. It is recommended that agriculture as a subject, should be made compulsory at schools as youth show no interest in farming and farmers. , Thesis (MPhil) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
Impact assessment of genetically modified TELA® Bt. maize variety adoption on yield, household income, technical efficiency and food security: a case of maize farmers in Limpopo and Mpumalanga Provinces, South Africa.
- Authors: Mailula, Lesiba Pertunia
- Date: 2023
- Subjects: Food security , Farmers -- Training of , Seed technology -- Economic aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28266 , vital:74040
- Description: The agricultural sector is widely recognized as a crucial factor for promoting sustainable economic development, reducing poverty, and ensuring food security in developing countries. However, in Africa, the agricultural sector continues to underperform, with growth rates falling behind the population growth, this can be attributed to various challenges, including climate change and pest infestation. This has over the years weakened the defence of crops leading to the disruptions in crop production and food security. As such, calls have been made that adoption of the agricultural technology may promote food security through high yields. This is because agricultural technology crops have improved varieties such as drought tolerance and pest resistance traits. However, adoption of improved agricultural technology in Africa has been very sluggish amongst smallholder farmers, particularly for GM seed, this is due to the on-going controversies and compliance requirements regarding GM technologies. The controversies are raised by the unknown benefits and risks associated with the adoption of GM seeds technology. Furthermore, there are mixed benefits associated with GM technology adoption as well as methodological and data gaps associated with assessment of GM impact on the farmer’s welfare. In 2016, five Bt. maize varieties trademarked TELA were developed through the WEMA project. Trials were approved and launched with smallholder farmers in various countries in Africa, and South Africa is not an exception. Several smallholder maize farmers have accessed the TELA Bt. maize varieties through local seed companies and have been producing it for the past seasons. Yet, no study that has been conducted on the impact of the GM TELA Bt. maize technology adoption on yield, income, food security and technical efficiency, hence, a need for such a study. The primary data was collected from 289 183 TELA Bt. and 106 non-TELA Bt. smallholder farmers in Mpumalanga and Limpopo provinces using convenience and snowball sampling techniques. Data were analysed using various analytical tools that included descriptive statistics, gross margin analysis, Household Dietary Diversity Score, Stochastic Frontier Model and the Propensity Score Matching, modelled through the Probit regression model. These tools were utilised to address the objectives. The descriptive statistics show that the TELA Bt. maize variety yielded 61.1 percent more maize output as compared to non-TELA Bt. maize farmers, with an average of 691kg ha and 429kg ha, respectively. The gross margin analysis showed higher subsequent income for the TELA Bt. maize farmers R2 834.93 compared to R2 124.96 for the non-TELA Bt. maize farmers. The results of the HDDS showed a marginal effect of TELA Bt. maize seed technology on food diversity. The average HDDS scores were 8.4 and 7.5 for the TELA Bt. and non-TELA Bt. maize farmers, respectively. The Stochastic Frontier Analysis SFA results revealed that both the TELA Bt. maize farmers and non-TELA Bt. maize farmers were technically inefficient. However, the TELA Bt. maize farmers were better-off than their counterparts, with mean technical efficiency scores of 0.416 and 0.328, respectively. The Propensity Score Matching PSM using the Probit model revealed that gender 0.6064, number of years in farming 0.0099 credit 1.1438 and market access 0.4427 had a positive and significant influence on the decision taken by the farmers to adopt TELA Bt. maize seed technology. However, access to extension services was found to have a negative and significant impact on the adoption of TELA Bt. maize seed technology. The Average Treatment Effect of the Treated ATT using the Nearest Neighbour Matching algorithm indicated that adoption of TELA Bt. maize technology improved farmers’ yields by 254.3kg, income by 0.36 cents and technical efficiency by 8.6 percent. There was no significant relationship observed between adoption of the GM technology and food security. Generally, the results from this study imply that adoption of GM TELA Bt. maize seed technology improves farmers’ yields, income, technical efficiency, as well as food security. The study therefore, recommends increased awareness of the GM seed technology benefits to farmers, coupled with training and capacity development to enhance adoption of seed technology towards improved farmers’ welfare. In addition, there is a need for sustained Research and Development investments towards GM seed technologies to enhance maize productivity and technical efficiency of the farmers. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Mailula, Lesiba Pertunia
- Date: 2023
- Subjects: Food security , Farmers -- Training of , Seed technology -- Economic aspects
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/28266 , vital:74040
- Description: The agricultural sector is widely recognized as a crucial factor for promoting sustainable economic development, reducing poverty, and ensuring food security in developing countries. However, in Africa, the agricultural sector continues to underperform, with growth rates falling behind the population growth, this can be attributed to various challenges, including climate change and pest infestation. This has over the years weakened the defence of crops leading to the disruptions in crop production and food security. As such, calls have been made that adoption of the agricultural technology may promote food security through high yields. This is because agricultural technology crops have improved varieties such as drought tolerance and pest resistance traits. However, adoption of improved agricultural technology in Africa has been very sluggish amongst smallholder farmers, particularly for GM seed, this is due to the on-going controversies and compliance requirements regarding GM technologies. The controversies are raised by the unknown benefits and risks associated with the adoption of GM seeds technology. Furthermore, there are mixed benefits associated with GM technology adoption as well as methodological and data gaps associated with assessment of GM impact on the farmer’s welfare. In 2016, five Bt. maize varieties trademarked TELA were developed through the WEMA project. Trials were approved and launched with smallholder farmers in various countries in Africa, and South Africa is not an exception. Several smallholder maize farmers have accessed the TELA Bt. maize varieties through local seed companies and have been producing it for the past seasons. Yet, no study that has been conducted on the impact of the GM TELA Bt. maize technology adoption on yield, income, food security and technical efficiency, hence, a need for such a study. The primary data was collected from 289 183 TELA Bt. and 106 non-TELA Bt. smallholder farmers in Mpumalanga and Limpopo provinces using convenience and snowball sampling techniques. Data were analysed using various analytical tools that included descriptive statistics, gross margin analysis, Household Dietary Diversity Score, Stochastic Frontier Model and the Propensity Score Matching, modelled through the Probit regression model. These tools were utilised to address the objectives. The descriptive statistics show that the TELA Bt. maize variety yielded 61.1 percent more maize output as compared to non-TELA Bt. maize farmers, with an average of 691kg ha and 429kg ha, respectively. The gross margin analysis showed higher subsequent income for the TELA Bt. maize farmers R2 834.93 compared to R2 124.96 for the non-TELA Bt. maize farmers. The results of the HDDS showed a marginal effect of TELA Bt. maize seed technology on food diversity. The average HDDS scores were 8.4 and 7.5 for the TELA Bt. and non-TELA Bt. maize farmers, respectively. The Stochastic Frontier Analysis SFA results revealed that both the TELA Bt. maize farmers and non-TELA Bt. maize farmers were technically inefficient. However, the TELA Bt. maize farmers were better-off than their counterparts, with mean technical efficiency scores of 0.416 and 0.328, respectively. The Propensity Score Matching PSM using the Probit model revealed that gender 0.6064, number of years in farming 0.0099 credit 1.1438 and market access 0.4427 had a positive and significant influence on the decision taken by the farmers to adopt TELA Bt. maize seed technology. However, access to extension services was found to have a negative and significant impact on the adoption of TELA Bt. maize seed technology. The Average Treatment Effect of the Treated ATT using the Nearest Neighbour Matching algorithm indicated that adoption of TELA Bt. maize technology improved farmers’ yields by 254.3kg, income by 0.36 cents and technical efficiency by 8.6 percent. There was no significant relationship observed between adoption of the GM technology and food security. Generally, the results from this study imply that adoption of GM TELA Bt. maize seed technology improves farmers’ yields, income, technical efficiency, as well as food security. The study therefore, recommends increased awareness of the GM seed technology benefits to farmers, coupled with training and capacity development to enhance adoption of seed technology towards improved farmers’ welfare. In addition, there is a need for sustained Research and Development investments towards GM seed technologies to enhance maize productivity and technical efficiency of the farmers. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
Investigation into response of wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa
- Authors: Mzileni L S
- Date: 2023
- Subjects: Bonanza farms , Wheat , Drought - tolerant plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27732 , vital:69397
- Description: Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Mzileni L S
- Date: 2023
- Subjects: Bonanza farms , Wheat , Drought - tolerant plants
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/27732 , vital:69397
- Description: Wheat is generally one of the dominant crops globally, being mainly used for human food and livestock feed. Due to climate change, drought makes it challenging to produce enough wheat mostly under dryland production regions in South Africa. Drought stress has severely reduced wheat yield by up to 70 percent, and adversely compromised wheat grain quality. The adoption of drought-tolerant cultivars offers a sustainable and low-cost solution for increasing wheat yields and minimise importing the crop to meet national requirements. The main objective of this study was to investigate the response of different wheat genotypes to drought and optimum conditions in the Eastern Cape Province, South Africa. Forty diverse wheat genotypes were evaluated in this study. The specific objectives were: (i) to evaluate the response of wheat genotypes under optimum and drought-stressed field conditions; (ii) to determine the effect of terminal drought stress on wheat grain quality composition; and (iii) to identify appropriate drought tolerance indices that can be used as selection tools under field conditions. This study was conducted in the field using a 5x8 alpha lattice design, replicated twice under two water regimes (drought and optimum) over two consecutive winter seasons of 2020 and 2021 at two different sites namely University of Fort Hare Research Farm in Alice, and Zanyokwe irrigation scheme in Keiskamahoek. Drought stress was imposed from 50% flowering up to physiological maturity. Data on agro-physiological traits such as duration to heading (DTH); flowering (DTF); maturity (DTM); plant height (HT); spike length (SL); number of spikelets per spike (SPS); kernels per spike (KPS); and grain yield (GY (kg/ha)) was subjected to the analysis of variance using Genstat 18th edition. As the study took place over two sites, a combined ANOVA table revealed significant differences (p0.001) among genotypes, and all interactions such as genotype by water regime (GWR); genotype by seasons (GS) for all studied traits. Notably, the extent and severity of drought differed between geographical regions and between seasons. This necessitated the adoption of the additive main effect and multiplicative interaction analysis (AMMI) for the identification of stable genotypes under two different water regimes over two sites. Regarding grain yield, superior and/or stable genotypes included G5 (4334 kg/ha under optimum, and 2871kg/ha under drought), and G22 (4418 kg/ha under optimum, and 2624kg/ha under drought) at the UFH site. G21 (3194 kg/ha under optimum, and 2938 kg/ha under drought), G33 (2552kg/ha under optimum, and 3810 kg/ha under drought), and G35 (2688 kg/ha under optimum, and 3309 kg/ha under drought) at the ZAN site. Stable genotypes across sites included G21 and G33. There were generally weak correlations between agro-physiological traits and grain yield. From the experiment, grain quality traits such as fixed protein (PF); wet gluten (WG); hectolitre mass (HLM); and thousand kernel weight (TKW) were also examined. A combined ANOVA revealed significant differences (p0.001) among the interaction of genotypes by environments (GE) for all traits except PF. This implies that the performance of wheat genotypes across sites was also different, and therefore, necessitated separate analysis of variance for each site. Significant differences (p0.001) among genotypes (G), water regimes (WR), and the interaction of genotypes by water regime (GWR) were observed for all studied quality traits except PF in both sites. GWR showed no significant differences for TKW in the ZAN site. The stability in the performance of genotypes across water regimes was further determined. G38 was stable for wet gluten; G31 and G26 were stable for PF; G36 was stable for HLM; and G11, G15, and G29 were stable for TKW at the UFH site. G6 was stable for both WG and PF; G13 and G15 were stable for HLM; and G35, G21, and G40 were stable for TKW at the ZAN site. These results suggest that the quality of wheat grains was affected under drought stress conditions except PF. Average grain yield data under both stressed (Ys) and optimum (Yp) conditions was used to compute a number of different drought tolerance indices. These include mean productivity (MP); geometric mean productivity (GMP); harmonic mean (HM); Tolerance index (TOL), stress susceptible index (SSI), sensitive drought index (SDI), and stress tolerance index (STI). The aim was to identify appropriate drought tolerance indices that can be used as selection tools under drought stress. MP, GMP, and HM were the more appropriate indices as they had a strong and positive correlation with grain yield under both drought and optimum conditions. However, genotypes G5, G22, G8, and G21 were more tolerant and stable as they showed high mean values. Based on the results, G19, G16, G2, and G20 were more sensitive to drought as they showed low values of MP, GMP, and HM. Overall, genotype: G5, G21, G22, and G33 are recommended for production under drought and optimum conditions, as they showed stable performance across water regimes. Principal component analysis also revealed that MP, GMP, and HM were the only indices that had positive loadings into the first principal component. , Thesis (MSc) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
Molecular characterization of integrons and their associated gene cassettes in multidrug-resistant enterobacteriaceae isolates from environmental sources and the exploration of antibiotic combination against some resistant strains
- Fadare, Folake Temitope https://orcid.org/0000-0001-5779-9798
- Authors: Fadare, Folake Temitope https://orcid.org/0000-0001-5779-9798
- Date: 2023
- Subjects: Enterobacteriaceae , Molecular microbiology , Enterobacteria
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27809 , vital:69942
- Description: Globally, the increasing rate of antimicrobial resistance against our currently available drugs has been a serious public concern. Due to the selective nature of antibiotics, bacteria are expected to develop resistance against them over time, but the current scourge of antimicrobial resistance is aggravated by factors other than the expected evolutionary trend. The use and overuse of antibiotics in clinical and agricultural contexts have led to the fast rise of multidrug-resistant MDR microorganisms. A scenario that necessitates an upsurge in the clinical failures observed with our current drug arsenals is expected to rise if left unchecked. One of the significant drivers implicated in the spread of antimicrobial resistance genes is the integrons. These are mobile genetic elements found on pathogenicity islands, transposons, and plasmids, easing their distribution among various bacteria. They are considered efficient gene expression systems that naturally capture, integrate gene cassettes GCs and immediately express the captured antimicrobial resistance genes on the GCs due to the inherent promoters on their structures. Integrons have been known to confer resistance against most classes of antibiotics. These include all known β-lactams, chloramphenicol, trimethoprim, erythromycin, aminoglycosides, quinolones, streptothricin, lincomycin, rifampicin, fosfomycin, and antiseptics of the quaternary ammonium compound family. They have been detected in bacterial populations under direct or indirect antibiotic pressure in clinical, agricultural, and environmental contexts. The emergence of MDR in Enterobacteriaceae is a critical public health issue that has attracted the World Health Organization WHO, which classified them as one of the critical priority pathogens urgently requiring new antibiotics. The resistance phenomenon has proven most of the current antibiotics ineffective, further compounded by the slow pace of the discovery of new antibiotics, necessitating the hunt for new, practical remedies. One of such is the exploration of synergy among existing antibiotics. Two medications combined have a higher impact, thereby allowing current antibiotics to be salvaged for use in treating MDR bacteria, even if the bacteria are resistant against one or both antibiotics separately. Hence, this research focused on the occurrence and prevalence of multidrug resistance and the characterization of integrons and their associated gene cassettes in members of Enterobacteriaceae, including Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Escherichia coli, and Citrobacter spp. recovered from animal droppings, rivers, and effluents of hospital and wastewater treatment plants in Eastern Cape Province, South Africa. The inhibitory effect of combining two drugs belonging to different antibiotic classes to obtain a possible potentiating effect against some multidrug-resistant Enterobacteriaceae isolates harbouring integrons were examined and studied. The isolates were identified using the conventional molecular Polymerase Chain Reaction with specific primers. The antimicrobial resistance profile and the production of Extended-spectrum and metallo β-lactamase were detected using disk diffusion technique DDT, double-disk synergy test DDST, and ethylenediaminetetraacetic acid EDTA tests, respectively. The PCR-based screening method, DNA sequencing analyses, and restriction fragment length polymorphism RFLP were used to characterize the integrons and their associated GCs. Furthermore, Enterobacterial Repetitive Intergenic Consensus ERIC PCR determined the genotypic relationships between some specific species. The various antibiotics' minimum inhibitory concentration MIC was determined using the broth microdilution, while the checkerboard method was used to determine the fractional inhibitory concentration indices FICIs. The time-kill assays TKAs were further used to confirm the synergism observed from the checkerboard assays. Most of the isolates were resistant against most antibiotics tested and were considered MDR. The least resistance was observed against imipenem, a carbapenem, one of the drugs of last resort. Also present were the ESBL and MBL producers, with a few isolates co-producing the enzymes. A high prevalence of integrons was observed in the isolates, with class 1 integrons being the most frequently detected. Some isolates co-harboured the intI1 and intI2 genes and were classified as class1 plus 2 integrons. Although Citrobacter spp. had the least number of isolates among the Enterobacteriaceae studied, it harboured the most diverse gene cassette arrays. The various gene cassette arrays were identified as follows: For Klebsiella spp. Aac 6 Ib, aadA1 dfrA1, and dfrA1 sat2; for Citrobacter spp., dfrA5 aac3 Ib, aac6 ib, aadA1dfrA1 aadA1, aadA1-dfrA1, aadA5 dfrA17, and dfrA21-aac3-Ib; for E. coli dfrA21- aac-3-Ib, dfrA5-aac-3-Ib, aadA1 dfrA1, and aadA5 dfrA17 and for E. cloacae aadA1 dfrA1, dfrA7 dfrA21 dfrA5 aac 3 Ib, and dfrA1 sat2. The GC array dfrA1 sat2 was the only array detected in class 2 integrons which are analogous to that found in Tn7, dfrA1-sat2-aadA1, with the deletion of the last GC aadA1. These detected GCs confer resistance against aminoglycosides, including streptomycin and spectinomycin, and trimethoprim, further increasing the resistance spectrum of the bacterial species harbouring them. The detection of integrons and their associated GC and the presence of these β-lactamases is also associated with coresistance against other classes of antibiotics by bacterial species harbouring them, further limiting treatment options. The checkerboard assays combining antibiotics against these drug-resistant integron harbouring Enterobacteriaceae revealed that 26.3 percent 10 over 38 of the interactions were categorized as synergistic, while 73.7 percent 28 over 38 were indifferent. None of the combinations was antagonistic. The TKAs revealed all the synergistic interactions as bactericidal. Therefore, the combinations of gentamicin with tetracycline, ciprofloxacin, and ceftazidime against Multidrug-resistant MDR Klebsiella pneumoniae; tetracycline-ceftazidime combination against MDR Escherichia coli, colistin combinations with ceftazidime and gentamicin, and tetracycline-gentamicin combinations against MDR Citrobacter freundii may be future therapeutic alternatives. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
- Full Text:
- Date Issued: 2023
- Authors: Fadare, Folake Temitope https://orcid.org/0000-0001-5779-9798
- Date: 2023
- Subjects: Enterobacteriaceae , Molecular microbiology , Enterobacteria
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27809 , vital:69942
- Description: Globally, the increasing rate of antimicrobial resistance against our currently available drugs has been a serious public concern. Due to the selective nature of antibiotics, bacteria are expected to develop resistance against them over time, but the current scourge of antimicrobial resistance is aggravated by factors other than the expected evolutionary trend. The use and overuse of antibiotics in clinical and agricultural contexts have led to the fast rise of multidrug-resistant MDR microorganisms. A scenario that necessitates an upsurge in the clinical failures observed with our current drug arsenals is expected to rise if left unchecked. One of the significant drivers implicated in the spread of antimicrobial resistance genes is the integrons. These are mobile genetic elements found on pathogenicity islands, transposons, and plasmids, easing their distribution among various bacteria. They are considered efficient gene expression systems that naturally capture, integrate gene cassettes GCs and immediately express the captured antimicrobial resistance genes on the GCs due to the inherent promoters on their structures. Integrons have been known to confer resistance against most classes of antibiotics. These include all known β-lactams, chloramphenicol, trimethoprim, erythromycin, aminoglycosides, quinolones, streptothricin, lincomycin, rifampicin, fosfomycin, and antiseptics of the quaternary ammonium compound family. They have been detected in bacterial populations under direct or indirect antibiotic pressure in clinical, agricultural, and environmental contexts. The emergence of MDR in Enterobacteriaceae is a critical public health issue that has attracted the World Health Organization WHO, which classified them as one of the critical priority pathogens urgently requiring new antibiotics. The resistance phenomenon has proven most of the current antibiotics ineffective, further compounded by the slow pace of the discovery of new antibiotics, necessitating the hunt for new, practical remedies. One of such is the exploration of synergy among existing antibiotics. Two medications combined have a higher impact, thereby allowing current antibiotics to be salvaged for use in treating MDR bacteria, even if the bacteria are resistant against one or both antibiotics separately. Hence, this research focused on the occurrence and prevalence of multidrug resistance and the characterization of integrons and their associated gene cassettes in members of Enterobacteriaceae, including Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Escherichia coli, and Citrobacter spp. recovered from animal droppings, rivers, and effluents of hospital and wastewater treatment plants in Eastern Cape Province, South Africa. The inhibitory effect of combining two drugs belonging to different antibiotic classes to obtain a possible potentiating effect against some multidrug-resistant Enterobacteriaceae isolates harbouring integrons were examined and studied. The isolates were identified using the conventional molecular Polymerase Chain Reaction with specific primers. The antimicrobial resistance profile and the production of Extended-spectrum and metallo β-lactamase were detected using disk diffusion technique DDT, double-disk synergy test DDST, and ethylenediaminetetraacetic acid EDTA tests, respectively. The PCR-based screening method, DNA sequencing analyses, and restriction fragment length polymorphism RFLP were used to characterize the integrons and their associated GCs. Furthermore, Enterobacterial Repetitive Intergenic Consensus ERIC PCR determined the genotypic relationships between some specific species. The various antibiotics' minimum inhibitory concentration MIC was determined using the broth microdilution, while the checkerboard method was used to determine the fractional inhibitory concentration indices FICIs. The time-kill assays TKAs were further used to confirm the synergism observed from the checkerboard assays. Most of the isolates were resistant against most antibiotics tested and were considered MDR. The least resistance was observed against imipenem, a carbapenem, one of the drugs of last resort. Also present were the ESBL and MBL producers, with a few isolates co-producing the enzymes. A high prevalence of integrons was observed in the isolates, with class 1 integrons being the most frequently detected. Some isolates co-harboured the intI1 and intI2 genes and were classified as class1 plus 2 integrons. Although Citrobacter spp. had the least number of isolates among the Enterobacteriaceae studied, it harboured the most diverse gene cassette arrays. The various gene cassette arrays were identified as follows: For Klebsiella spp. Aac 6 Ib, aadA1 dfrA1, and dfrA1 sat2; for Citrobacter spp., dfrA5 aac3 Ib, aac6 ib, aadA1dfrA1 aadA1, aadA1-dfrA1, aadA5 dfrA17, and dfrA21-aac3-Ib; for E. coli dfrA21- aac-3-Ib, dfrA5-aac-3-Ib, aadA1 dfrA1, and aadA5 dfrA17 and for E. cloacae aadA1 dfrA1, dfrA7 dfrA21 dfrA5 aac 3 Ib, and dfrA1 sat2. The GC array dfrA1 sat2 was the only array detected in class 2 integrons which are analogous to that found in Tn7, dfrA1-sat2-aadA1, with the deletion of the last GC aadA1. These detected GCs confer resistance against aminoglycosides, including streptomycin and spectinomycin, and trimethoprim, further increasing the resistance spectrum of the bacterial species harbouring them. The detection of integrons and their associated GC and the presence of these β-lactamases is also associated with coresistance against other classes of antibiotics by bacterial species harbouring them, further limiting treatment options. The checkerboard assays combining antibiotics against these drug-resistant integron harbouring Enterobacteriaceae revealed that 26.3 percent 10 over 38 of the interactions were categorized as synergistic, while 73.7 percent 28 over 38 were indifferent. None of the combinations was antagonistic. The TKAs revealed all the synergistic interactions as bactericidal. Therefore, the combinations of gentamicin with tetracycline, ciprofloxacin, and ceftazidime against Multidrug-resistant MDR Klebsiella pneumoniae; tetracycline-ceftazidime combination against MDR Escherichia coli, colistin combinations with ceftazidime and gentamicin, and tetracycline-gentamicin combinations against MDR Citrobacter freundii may be future therapeutic alternatives. , Thesis (MSci) -- Faculty of Science and Agriculture, 2023
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- Date Issued: 2023