No description available.

Submitted in complete fulfillment of the requirements for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2012. / Immunomodulation using plants is of primary interest in scientific communities because it provides an alternative to conventional chemotherapy for a wide range of diseases. It is based on the ability of the plants to effectively modulate immune functions, thus being able to promote positive health and maintain the body’s resistance to infection. This research is aimed to evaluate the immunomodulatory potential of fourteen traditional leafy vegetables from Kwa-Zulu Natal, South Africa on human peripheral blood mononuclear cells (PBMC). In this study the methanolic and aqueous extracts were screened for lymphocyte proliferation using the MTT assay. The cytokine response was evaluated by measuring the secretion of interleukin 10 (IL-10) and interferon-gamma (IFN-γ) using the ELISA assay. The subpopulation of T cells viz., CD4+, CD8+, NK and B cells were measured by flow cytometry. Most of the methanolic extracts stimulated PBMC’s whilst a few suppressed lymphocyte proliferation. Most of the aqueous extracts were inactive. The methanolic extracts of Amaranthus hybridus and Centella asiatica stimulated PBMC’s and showed an increase in IFN-γ secretion and the CD8+ cytotoxic T cells and B cells. Thus, they induced the Tc-1 immune response and stimulated cell mediated immunity. The methanolic extracts of Asystasia gangetica, Bidens pilosa, Emex australis, Justicia flava Momordica balsamina, Oxygonum sinuatum, Senna occidentalis and Sonchus oleraceous and the aqueous extracts of Amaranthus spinosus and Asystasia gangetica, Ceratotheca triloba, Oxygonum sinuatum, Physalis viscosa and Sonchus oleaceous stimulated PBMC’s and showed an increase in IL-10 secretion and the CD8+ cytotoxic T cells and B cells. Thus, they induced the Tc-2 immune response and stimulated humoral immunity. Also, the methanolic extracts of Amaranthus spinosus and Ceratotheca triloba and the aqueous extracts of Bidens pilosa and Justicia flava increased both IL-10 and IFN-γ secretion and the CD8+ vii cytotoxic T cells indicating the stimulation of both the Tc1 and Tc2 cytokine profiles. The elevated secretion of IFN-γ and IL-10 caused by the extracts can be attributed to the CD8+ cytotoxic T cells and B cells. The findings of this study show that leafy vegetables hold promise as immunomodulatory candidates. They may enhance cell-mediated immune functions by a pro-inflammatory response whilst some can promote humoral immune functions by means of an anti-inflammatory response. Further investigation should be considered on the effect of the extracts on other immune parameters. / National Research Foundation

This study used cross-sectional survey data to estimate farmers` perceptions of, and commonly cultivated ILVs, factors that influence the participation of smallholder famers in the production of Indigenous Leafy Vegetables and its contribution to household food security]. With regard to farmers` perceptions of ILVs, descriptive results reveal that a majority of the people from the study area share positive perceptions with respect to ILVs. Regression estimates for determinants of participation indicate that the production of ILVs is primarily conditioned by shared perceptions and institutional factors rather than the socio-economic attributes of farmers. Public policies that address the institutional framework (extension, credit, market and social networks) in favour of ILVs are more likely to promote production. Also, more research on the documentation and benefits of ILVs, supported by investments targeting educational campaigns towards promoting positive attitudes and dispelling fears and myths surrounding ILVs, will further promote production. With reference to the contribution of ILVs to food security, descriptive results indicate that participation in the production of ILVs leads to a higher HDDS and a lower HFIAS. Regression estimates further revealed that participation positively contributes to a higher HDDS and a lower HFIAS, suggesting that households who participate in the production of ILVs are more likely to be food secure than non-participants. Therefore, participation in the production of ILVs has significant potential to address household food security.

Thesis(M.Sc.(Agriculture Horticulture)) -- University of Limpopo, 2019 / Innovative methods of preserving the quality of traditionally processed green leafy vegetables are underway in Africa. Improvement of processing and preservation methods of leafy vegetables is another way of overcoming perishability restrictions and guaranteeing continued quality food supply in rural areas. The objectives of this study were: to determine the effect of time-based oven-drying on (1) mineral composition, (2) proximate composition and (3) microbial profiling of cowpea (Vigna unguiculata). Separate experiments were conducted for raw and cooked cowpea leaves with four treatments, viz 0 (sun dried), 24, 48 and 72 hours of oven-drying, arranged in a randomised complete block design with 5 replications. In raw cowpea leaves, relative to control (sun-drying), oven-drying period 48hrs, significantly decreased Potassium (K), Manganese (Mn), and Sodium (Na) content in raw cowpea leaves by 6, 9 and 13%, respectively. Similarly, oven-drying period 72hrs significantly decreased Ca, Fe, Mg, Zn, P and S by 5, 11, 16, 18 and 57%, respectively. In cooked cowpea leaves, relative to control (sun-drying), oven-drying period 24hrs significantly increased Na by 18%. Similarly 48hrs oven-drying periods increased Fe and K by 6 and 8%, respectively. Similarly, oven-drying period 72hrs significantly increased Ca, Mg and Mn by 8, 8 and 3%, respectively. In contrast, oven-drying period 72hrs significantly reduced Zn, P and S by 16, 10 and 39%, respectively. Relative to control (sun-drying), oven-drying period 24hrs significantly increased fat by 46% in raw cowpea leaves, however oven-drying period 72hrs significantly decreased protein, moisture, ash, fibre and carbohydrate by 10, 29, 18, 0.5, and 7% respectively. In contrast, relative to control (sun-drying), 72hrs increased energy by 3%. In cooked cowpea leaves, relative to control (sun-drying), ovendrying period 24hrs significantly increased energy by 1%. In contrast, relative to control (sun-drying) 72hrs oven-drying period decreased energy by 1%. Similarly, oven-drying 72hrs significantly decreased protein, moisture, ash, fat, fibre and carbohydrate by 8, 14, 13, 19, 0.4 and 10% respectively. Relative to control (sun-drying), oven-drying periods 24hrs significantly increased Staphylococcus spp. in raw cowpea leaves by 6%, respectively. Relative to control (sun-drying) 72hrs oven-drying period significantly decreased Shigella spp. by 92%, respectively. In cooked leaves, relative to control (sundrying), 72hrs drying periods decreased both Shigella spp. and Staphylococcus spp. by 99 and 21%, respectively. Total coliforms unit of Salmonella spp, Escherichia coli, Pseudomonas spp, and Bacillus cereus were absent and/or at an undetectable level according to the Tempo Biomerieux system results. In conclusion, cooked leaves retained most essential mineral elements as compared to raw when subjected to 72hrs of ovendrying as there was an improvement in the concentration of Ca, Fe, K, Mg, Mn and Na. However, in both raw and cooked cowpea leaves proximate composition was negatively affected as there was a decrease in protein content. Oven-drying period of 24 hours can be used to minimize the loss of protein. Cooked cowpea leaves subjected to 72hrs of oven-drying had least total coliforms for both Shigella spp and Staphylococcus spp, therefore have potential to serve as an alternative to sun-drying to reduce microorganism causing spoilage in leafy vegetables. Drying raw cowpea leaves under oven-drying periods less than 72 hours should be avoided as it reduces the mineral concentration and increase microbial count of microorganisms responsible for spoilage / National Research Foundation (NRF)

Food insecurity remains a major challenge affecting the rural poor households in South Africa. The consumption of green leafy vegetables is important to address micronutrients deficiency in rural communities and, at the same time, it contributes to fibre intake. This study investigated the people’s attitude towards the cultivation and utilisation of ILVs in rural communities. A cross-section survey study was conducted among 1 000 respondents in randomly selected households in communities. The majority of respondents were not willingly consuming ILVs. This is because most consumers were black and of the low-income group. ILVs that are consumed grow mainly in the wild. The regular consumption of these vegetables as indicated in this study is interesting, as this will help in mitigating micronutrient deficiency. Furthermore, these vegetables could be incorporated in formulated food to improve iron and zinc, especially in infant foods formulation. Based on the findings of this study it would be important to find ways of encouraging cultivation of ILVs for both nutrition and as income generating activities. / Life and Consumer Science / M.CS.

M. Tech. Agriculture / Leafy vegetables, Swiss chard (Beta vulgaris L. var. cicla), lettuce (Lactuca sativa L.) and mustard spinach (Brassica juncea), are widely grown in South Africa. These leafy vegetables are popular owing to their availability and nutritional properties. Optimisation of crop nutrition is essential to maximize yield and quality of vegetables. Therefore, a study was conducted to evaluate the effect of different levels of nitrogen application on growth and quality parameters of leafy vegetables when grown in a non-circulating hydroponic system. The objective of this study is two-fold: primarily, to determine the influence of nitrogen on growth, yield and overall quality of Swiss chard, lettuce and mustard spinach grown in a non-circulating hydroponic system, and secondly, to determine the effect of nitrogen applications on bioactive compounds and antioxidants, such as antioxidant scavenging activities, ascorbic acid, total phenolics and flavonoids.

M. Tech. Agriculture. / Aims of this study was to select a suitable modified atmosphere packaging that retained the overall quality and bioactive compounds of the traditional leafy vegetables during storage. In this study, three types of biorientated polypropylene packaging namely BOPP04, BOPP05 and BOPP06 with different perforations were tested on retention of quality parameters (weight loss, leaf yellowing, colour L*, C*, h&#x00BA%x;), decay, chlorophyll a, chlorophyll b, bioactive compounds (carotenoids, ascorbic acid, total phenolic compounds), antioxidant scavenging activity, and sensory properties at 10 &#x00BA%x;C at 2 day intervals up to 14 days.Films without perforation, with macro perforation and unpacked leaves were included for comparison.

African leafy vegetables have been shown and suggested to have potential to contribute to human diets and alleviate malnutrition; however, their levels of utilisation are currently low especially in South Africa. This is because there is limited access to these crops due to low availability in the market. Limited access is attributed, in part, to the lack of commercialisation as a result of limited agronomic information describing optimum management options for these leafy vegetables. Availability of such information would contribute to successful commercialisation of these crops. The primary objective of this study was to establish optimum agronomic management factors for Amaranthus cruentus, Corchorus olitorius, Vigna unguiculata and Brassica juncea for irrigated commercial production in South Africa. Seeds of Amaranthus cruentus, Corchorus olitorius were obtained from the Agricultural Research Council seed bank; Vigna unguiculata were obtained from Hydrotech and Brassica juncea seeds were obtained from Stark Ayres. The project consisted of three field studies whose overall objective was to evaluate growth and yield responses of the selected African leafy vegetables to agronomic factors under irrigated commercial production. These field studies comprised of two single factors; summer trials (planting density and nitrogen on three selected crops) and a combined winter trial (nitrogen, irrigation, plant density and planting date on a winter crop). Chapter three (3) investigated the effect of plant density on growth, physiology and yield responses of Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata to three plant densities under drip irrigated commercial production. The plant density levels of 100 000, 66 666 and 50 000 plants/ha were used in the 2011/12 and 2012/13 summer seasons. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Amaranthus cruentus and Corchorus olitorius showed better leaf quality at lower plant density of 50 000 plants ha-1 than at 66 666 plants ha-1 and 100 000 plants ha-1. These results are based on bigger leaves expressed as leaf area index (LAI), better colour expressed as chlorophyll (CCI) and higher biomass per plant observed in these crops at 50 000 plants ha-1 in comparison to 66 666 plants ha-1 and 100 000 plants ha-1. In Vigna unguiculata there were no responses observed in LAI and CCI. In Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata fresh and dry mass yield of leaves were higher at 100 000 plants ha-1 compared to other treatments. In A. cruentus and C. olitorius, higher leaf quality parameters (CCI, plant height, leaf number, biomass per plant and LAI) indicated that these crops can perform better at lower densities of 50 000 than at 66 666 plants ha-1 and 100 000 plants ha-1 Therefore, using 50 000 plants ha- 1 is suitable for commercial production of A. cruentus and C. olitorius. In Vigna unguiculata, a plant density of 100 000 plants ha-1 produced the highest fresh and dry mass per unit area without compromising quality in terms of the leaf size (LAI) and colour (CCI). Therefore 100 000 plants ha-1 is a density recommended for commercial production in V. unguiculata.Chapter four (4) was conducted to investigate growth, physiology and yield responses of A. cruentus, C. olitorius and V unguiculata to nitrogen application under drip irrigated commercial production. Three nitrogen treatments levels were used viz. 0, 44 and 88 kg N ha- 1 in 2011/12 season and four nitrogen treatments levels viz. 0, 50, 100 and 125 kg N ha-1 were used in 2012/13 summer season. The nitrogen levels selected for each season were based on recommendations for Amaranthaceae species, Swiss chard (Beta vulgaris L.var cicla) derived from soil analysis of the trial (field) site. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results showed that application of nitrogen at 44 kg N ha- 1 in 2011/12 summer season and 100 kg N ha-1 in 2012/13 summer season improved LAI, CCI, biomass per plants and yield in A. cruentus. A similar trend was observed in C. olitorius except that 44 kg N ha-1 improved stem fresh yield. Further increase in nitrogen fertiliser above 44 kg N ha-1 during the 2011/12 season and above 100 kg N ha-1 in 2012/13 summer season reduced leaf quality and yield in both crops. In V. unguiculata, nitrogen application showed a slight increase in yield values from 0 to 44 kg N ha-1 followed by decrease at 88 kg N ha-1 in 2011/12 summer season; however, this increase in yield was not significant. During the 2012/13 summer season, yield in terms of fresh weight was significantly (P<.001) reduced by applying nitrogen at various levels. However, leaf dry matter content increased significantly (P<.001) with increase in nitrogen from 0 kg up to 100 kg N ha-1, then remained unchanged at 125 kg N ha-1. Therefore, the current study recommends that C. olitorius and A. cruentus could be commercialised at 44 kg N ha-1 and 100 kg N ha-1 which were lower nitrogen application rates than those recommended for Amaranthaceae species. In V. unguiculata, 50 kg N ha-1 improved leaf number; however, this did not translate to any fresh yield advantage, implying that the optimum rate for nitrogen application might be lower than 50 kg N ha-1. Therefore, nitrogen rates less than the ones used in the current study are recommended for V. unguiculata. Chapter five (5) was conducted in winter and it was necessitated by observations made primarily in the previous studies which focused on the effects of single factors such as plant density, planting date and nitrogen deficits. Therefore, there was a need to address interactions between irrigation, nitrogen, spacing and planting date. The objective of this study was to evaluate growth, physiology and yield responses of Brassica juncea to different agronomic and management factors in the 2012 and 2013 seasons. The treatments were as follows: two planting dates in main plot (1 June and 18 July, 2012); two irrigation frequency in sub main plot (once and three times a week); three nitrogen levels (0, 50, 100 kg N ha-1) and three plant densities (133 333, 80 000, 50 000 plants ha-1) as subplots. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results from this study showed a significant interaction effect on plant height, LAI, CCI and CF. Crops irrigated thrice or once a week with 50 kg N ha-1 combined with 50 000 plants ha-1 produced tall plants and bigger leaves (LAI) in the early planting date (1 June) compared to other combinations. Irrigating three times a week combined with nitrogen application at 100 or 50 kg N ha-1 improved CF for late planting date (18 July) in comparison to other combinations. Irrigating once a week combined with nitrogen application at 100 kg N ha-1 increased CCI. There was no significant interaction effect on yield. Application of nitrogen at 50 and 100 kg N ha-1 significantly (P>0.05) increased yield in early and late planting dates compared to the control (0 kg N ha-1), in 2012 and 2013 winter season. Irrigating three times a week led to a significant (P<0.05) increase in yield in the late planting date (18th July) and early planting date (1st June) in 2013 season. Higher plant density of 133 333 plants ha-1 resulted in significantly (P<0.05) higher yield in terms of fresh mass and leaf number in the late planting date 18 July in 2012 and 2013 seasons. However, leaf quality parameters such as leaf size and colour was compromised at 133 333 plants ha-1 relative to 50 000 plants ha-1. Therefore, farmers are recommended to plant early, apply 50 kg N ha-1, irrigate thrice a week and utilise a spacing of 50 000 plants ha-1. The current study indicates that growth and yield of traditional leaf vegetables can be optimised through improved agronomic practise. / Agriculture and Life Sciences / D. Litt. et. Phil. (Agriculture)

African leafy vegetables have been shown and suggested to have potential to contribute to human diets and alleviate malnutrition; however, their levels of utilisation are currently low especially in South Africa. This is because there is limited access to these crops due to low availability in the market. Limited access is attributed, in part, to the lack of commercialisation as a result of limited agronomic information describing optimum management options for these leafy vegetables. Availability of such information would contribute to successful commercialisation of these crops. The primary objective of this study was to establish optimum agronomic management factors for Amaranthus cruentus, Corchorus olitorius, Vigna unguiculata and Brassica juncea for irrigated commercial production in South Africa. Seeds of Amaranthus cruentus, Corchorus olitorius were obtained from the Agricultural Research Council seed bank; Vigna unguiculata were obtained from Hydrotech and Brassica juncea seeds were obtained from Stark Ayres. The project consisted of three field studies whose overall objective was to evaluate growth and yield responses of the selected African leafy vegetables to agronomic factors under irrigated commercial production. These field studies comprised of two single factors; summer trials (planting density and nitrogen on three selected crops) and a combined winter trial (nitrogen, irrigation, plant density and planting date on a winter crop). Chapter three (3) investigated the effect of plant density on growth, physiology and yield responses of Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata to three plant densities under drip irrigated commercial production. The plant density levels of 100 000, 66 666 and 50 000 plants/ha were used in the 2011/12 and 2012/13 summer seasons. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Amaranthus cruentus and Corchorus olitorius showed better leaf quality at lower plant density of 50 000 plants ha-1 than at 66 666 plants ha-1 and 100 000 plants ha-1. These results are based on bigger leaves expressed as leaf area index (LAI), better colour expressed as chlorophyll (CCI) and higher biomass per plant observed in these crops at 50 000 plants ha-1 in comparison to 66 666 plants ha-1 and 100 000 plants ha-1. In Vigna unguiculata there were no responses observed in LAI and CCI. In Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata fresh and dry mass yield of leaves were higher at 100 000 plants ha-1 compared to other treatments. In A. cruentus and C. olitorius, higher leaf quality parameters (CCI, plant height, leaf number, biomass per plant and LAI) indicated that these crops can perform better at lower densities of 50 000 than at 66 666 plants ha-1 and 100 000 plants ha-1 Therefore, using 50 000 plants ha- 1 is suitable for commercial production of A. cruentus and C. olitorius. In Vigna unguiculata, a plant density of 100 000 plants ha-1 produced the highest fresh and dry mass per unit area without compromising quality in terms of the leaf size (LAI) and colour (CCI). Therefore 100 000 plants ha-1 is a density recommended for commercial production in V. unguiculata.Chapter four (4) was conducted to investigate growth, physiology and yield responses of A. cruentus, C. olitorius and V unguiculata to nitrogen application under drip irrigated commercial production. Three nitrogen treatments levels were used viz. 0, 44 and 88 kg N ha- 1 in 2011/12 season and four nitrogen treatments levels viz. 0, 50, 100 and 125 kg N ha-1 were used in 2012/13 summer season. The nitrogen levels selected for each season were based on recommendations for Amaranthaceae species, Swiss chard (Beta vulgaris L.var cicla) derived from soil analysis of the trial (field) site. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results showed that application of nitrogen at 44 kg N ha- 1 in 2011/12 summer season and 100 kg N ha-1 in 2012/13 summer season improved LAI, CCI, biomass per plants and yield in A. cruentus. A similar trend was observed in C. olitorius except that 44 kg N ha-1 improved stem fresh yield. Further increase in nitrogen fertiliser above 44 kg N ha-1 during the 2011/12 season and above 100 kg N ha-1 in 2012/13 summer season reduced leaf quality and yield in both crops. In V. unguiculata, nitrogen application showed a slight increase in yield values from 0 to 44 kg N ha-1 followed by decrease at 88 kg N ha-1 in 2011/12 summer season; however, this increase in yield was not significant. During the 2012/13 summer season, yield in terms of fresh weight was significantly (P<.001) reduced by applying nitrogen at various levels. However, leaf dry matter content increased significantly (P<.001) with increase in nitrogen from 0 kg up to 100 kg N ha-1, then remained unchanged at 125 kg N ha-1. Therefore, the current study recommends that C. olitorius and A. cruentus could be commercialised at 44 kg N ha-1 and 100 kg N ha-1 which were lower nitrogen application rates than those recommended for Amaranthaceae species. In V. unguiculata, 50 kg N ha-1 improved leaf number; however, this did not translate to any fresh yield advantage, implying that the optimum rate for nitrogen application might be lower than 50 kg N ha-1. Therefore, nitrogen rates less than the ones used in the current study are recommended for V. unguiculata. Chapter five (5) was conducted in winter and it was necessitated by observations made primarily in the previous studies which focused on the effects of single factors such as plant density, planting date and nitrogen deficits. Therefore, there was a need to address interactions between irrigation, nitrogen, spacing and planting date. The objective of this study was to evaluate growth, physiology and yield responses of Brassica juncea to different agronomic and management factors in the 2012 and 2013 seasons. The treatments were as follows: two planting dates in main plot (1 June and 18 July, 2012); two irrigation frequency in sub main plot (once and three times a week); three nitrogen levels (0, 50, 100 kg N ha-1) and three plant densities (133 333, 80 000, 50 000 plants ha-1) as subplots. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results from this study showed a significant interaction effect on plant height, LAI, CCI and CF. Crops irrigated thrice or once a week with 50 kg N ha-1 combined with 50 000 plants ha-1 produced tall plants and bigger leaves (LAI) in the early planting date (1 June) compared to other combinations. Irrigating three times a week combined with nitrogen application at 100 or 50 kg N ha-1 improved CF for late planting date (18 July) in comparison to other combinations. Irrigating once a week combined with nitrogen application at 100 kg N ha-1 increased CCI. There was no significant interaction effect on yield. Application of nitrogen at 50 and 100 kg N ha-1 significantly (P>0.05) increased yield in early and late planting dates compared to the control (0 kg N ha-1), in 2012 and 2013 winter season. Irrigating three times a week led to a significant (P<0.05) increase in yield in the late planting date (18th July) and early planting date (1st June) in 2013 season. Higher plant density of 133 333 plants ha-1 resulted in significantly (P<0.05) higher yield in terms of fresh mass and leaf number in the late planting date 18 July in 2012 and 2013 seasons. However, leaf quality parameters such as leaf size and colour was compromised at 133 333 plants ha-1 relative to 50 000 plants ha-1. Therefore, farmers are recommended to plant early, apply 50 kg N ha-1, irrigate thrice a week and utilise a spacing of 50 000 plants ha-1. The current study indicates that growth and yield of traditional leaf vegetables can be optimised through improved agronomic practise. / Agriculture and Life Sciences / D. Litt. et. Phil. (Agriculture)

Thesis (M. Agricultural Management (Agronomy)) -- University of Limpopo, 2018 / A survey study identified indigenous leafy vegetables (ILVs) utilized by rural communities in Limpopo Province in the three districts of Capricorn, Sekhukhune and Vhembe focusing on their availability, agronomic practices, marketing, medicinal and cultural roles, as well as their nutritional value. An ILV that was highly preferred and with good marketing potential was identified for further studies on its response to planting density and nitrogen fertilizer rate. A questionnaire survey was used to gather information about types of ILVs utilised, their production practices, marketing of ILVs and their importance in medicinal and cultural roles. Data collected were subjected to analysis using the Statistical Package for Social Sciences (SPSS) using descriptive statistics. Results showed that there were 45 different types of ILVs identified from the three districts in Limpopo Province. Farmers indicated that cultivation of these vegetables was mostly done from October to January in Sekhukhune and Capricorn district while in Vhembe it was practiced all year round. Most of farmers in Vhembe district used inorganic fertilizer during planting while farmers in Sekhukhune and Capricorn districts used organic fertilizers such as cattle manure. Irrigation was commonly used in Vhembe district through furrow irrigation system whereas in Capricorn and Sekhukhune districts most farmers relied on rainfall. Farmers indicated that harvesting was done at an early growing stage of the crop. Indigenous leafy vegetables were mostly marketed in local communities. Several ILVs were identified as preferred and regularly consumed as vegetables. Spider plant (Cleome gynandra) and nightshade (Solanum retroflexum) were identified as the most consumed ILVs in the three districts. Comparing the market potential of the two vegetables, S. retroflexum was chosen for further studies on its response to plant density and nitrogen fertilizer rate. The first study investigated the effect of varying plant density (inter and intra-row spacing) and the second study evaluated the response of intra-row spacing and nitrogen fertilizer (LAN-28%N) rate on growth and yield of S. retroflexum during 2014 (April to May) and 2015 (March to May) growing seasons. The plant density experiment was laid out as a 3 x 4 factorial arrangement in a randomised complete block design (RCBD) with three replications. The treatment factors were 3 inter-row spacings of 30, 45 and 60 cm and 4 intra-row spacings of vi 7.5, 15, 22.5 and 30 cm. The data collected included plant height, plant vigour, number of leaves and branches per plant as well as plant leaf yield. Data were subjected to analysis of variance (ANOVA) using STATISTIX 10.0 package and mean treatments were separated using Turkey HSD at 5% probability level. The results revealed that growth parameters (plant height, plant vigour, number of branches and leaves) and plant leaf yield were significantly influenced by the combined inter and intra-row spacings. Closer inter-row spacings of 30 cm and 45 cm, and intra-row spacings of 7.5 and 15 cm produced the highest values of parameters and plant leaf yield. The combined spacings of 30 x 7.5 cm produced the highest plant leaf yield. The second study was also laid out as a randomised complete block design (RCBD) with three replications. The treatments were 6 x 2 factorial arrangement: 6 levels of nitrogen (LAN-28%N) at 0, 20, 40, 60, 80 and 100 kg N/ha and two intra-row spacings of 15 and 30cm. Inter-row spacing of 30 cm was used. The nitrogen fertilizer was applied a week after transplanting and repeated a week after first harvesting. Data was subjected to analysis of variance (ANOVA) using STATISTIX 10.0 package. Where significant differences were detected, means were separated using Turkey HSD at 5% propability level. The results suggested that both nitrogen fertilizer and spacing can be used to enhance growth and leaf yield of S. retroflexum vegetable. Nitrogen fertilizer rate and plant density significantly (P≤0.05) affected plant growth and plant leaf yields. Growth parameters and leaf yield were optimised using closer spacing of 15 cm and applying nitrogen at 60 kg N/ha. The application of 60 kg N/ha and 15 cm spacing was therefore recommended for the production of S. retroflexum as a vegetable, if planted at 30 cm inter-row spacing. Key words: Indigenous leafy vegetables, agronomic practices, Solanum retroflexum, planting density, nitrogen fertilizer, planting date