Thesis (MScAgric (Agronomy)--University of Stellenbosch, 2007. / The Cape Floristic Region is a highly distinctive phytogeographical unit which is recognized as a floral Kingdom on its own. Buchu (Agathosma betulina) plants fall under this important Kingdom. Buchu is one of the traditional medicinal plants originating in the Western Cape province of South Africa and the essential oil derived from the leaves is exported in large volumes. Due to high demand, under supply, restrictions of wild harvesting and high prices for Buchu essential oil, growers have started to introduce and commercialize this species as a crop. This commercialization of Buchu necessitated agronomic research to optimize production techniques. The objective of this study was to determine the optimum pH range for the cultivation of high yielding Buchu with acceptable essential oil quality under controlled conditions and compare this with the conditions in the natural habitat. Plant, soil and climatic data were gathered from eleven sites in the natural habitat of Buchu (A. betulina) in the Cederberg Mountains. At all sites most rainfall occurred from May to September, while high temperatures were recorded in summer. Soil analyses indicated low levels of nutrients and low soil pH, ranging from 3.7 to 5.3 at all the sites studied. Low levels of nutrients were also obtained from foliar analysis collected from plants at each of the different sites. Chemical analyses of the essential oil indicated that the plants were from a high quality diosphenol chemotype. In the greenhouse experiment, five different pH levels (pH 33.99, 4-4.99, 5-5.99, 6-6.99 and 7-7.99) were evaluated to determine the effect on growth, yield and quality of A. betulina. Complete nutrient solutions were used to irrigate the plants grown in pots filled with a sand and coco peat mixture. Although the plants subjected to the pH treatment of 4-4.99 tended to have the highest growth rate and yield, this did not differ significantly (P=0.05) from plants subjected to pH values between 3 and 6.99. In contrast, the pH 7-7.99 treatment lead to reduced growth and lower vegetative yields. Levels of nutrients obtained from the leaf mineral analysis differed significantly with different pH treatments. High pH levels resulted in high nitrogen, phosphorus, sodium, manganese and boron contents, but lower contents of copper. Nitrogen, phosphorus, calcium and zinc were higher than those recorded for plants from their natural habitat, but still within the norm reported for most plants. Levels of manganese, sodium, magnesium and copper were found to be more or less similar to the values obtained in plants from the natural habitat. No significant differences were found in essential oil quality in response to the pH treatments. However, high pulegone levels (10.8 to 13.2 %) were obtained from all the treatments in the greenhouse experiment. The high levels of this essential oil constituent could have a negative effect on the marketability of the oil and this aspect may need some attention in future studies.

Com o monitoramento periódico da solução do solo, pode-se determinar a condutividade elétrica e a concentração de íons específicos, essenciais à nutrição das plantas. Dentre as técnicas de extração da solução do solo, o extrator de cápsula porosa destaca-se pela praticidade em campo, baixo custo, fácil manejo e boa precisão. Com isso objetivou-se estudar os efeitos de diferentes níveis de salinidade do solo sobre as variáveis fenológicas e de produção da berinjela, cultivada em vasos e em ambiente protegido, e averiguar se a manutenção da condutividade elétrica em um determinado nível promove incremento da produção, quando contrastada com o manejo tradicional da fertirrigação. Conduziu-se um estudo em ambiente protegido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,3; S2 = 2,4; S3 = 3,6; S4 = 4,5; S5 = 5,6 e S6 = 6,4 dS m-1) e dois manejos de fertirrigação: com controle da condutividade elétrica da solução do solo (M1), e o tradicional (M2), obedecendo a curva de absorção de nutrientes da cultura anteriormente estabelecida. O delineamento estatístico adotado foi o de blocos casualizados completos, com quatro repetições, ficando os fatores estudados arranjados no esquema fatorial 6 x 2. Os diferentes níveis de salinidade inicial do solo foram obtidos com solos de cultivos anteriores, no qual tinha-se como fonte de variação o nível de condutividade elétrica (CE), ocasionada pela adição de fertilizantes em ambiente protegido. A condutividade elétrica da solução foi medida após o término de cada evento de irrigação, utilizando-se extratores com cápsulas porosas. Os resultados revelaram que os níveis de salinidade do solo provenientes do acúmulo de sais fertilizantes afetou diretamente as variáveis consumo hídrico, produção de frutos, produção de matéria seca, índice de área foliar e o desenvolvimento vegetativo das plantas. O uso dos extratores de solução permitiu auxiliar o manejo da fertirrigação, mantendo os níveis desejados de salinidade da solução do solo ao longo do tempo. Verificou-se que a redução média na produção da cultura da berinjela, em estufa, foi da ordem de 8,65% para o incremento de 1 dS m-1 na salinidade do solo, acima da salinidade limiar, que foi de 1,71 dS m-1. / Periodic monitoring of soil solution allow to determine the electrical conductivity and concentration of specific ions essential to plant nutrition. Among the extraction techniques of soil solution, the porous cup extractors distinguished by their practicality in the field, low cost and good accuracy. This study has to aim to evaluate the effects of different levels of soil salinity on phenological and production of eggplant grown in pots in a greenhouse, and compare whether the control of the electrical conductivity in a certain level promotes increase the yield when compare to the traditional fertigation management . A study was conducted in a greenhouse in the Department of Biosystems Engineering, ESALQ / USP, Piracicaba, SP, Brazil. The treatments consisted of a combination of two factors: six levels of initial soil salinity (S1 = 1.3, S2 = 2.4, S3 = 3.6, S4 = 4.5, S5 = 5.6 and S6 = 6.4 dS m-1) and two fertigation management: electrical conductivity control of soil solution (M1) and traditional (M2) by following the absorption curve of nutrients from the crop previously established. The statistical design was a randomized complete block with four repetitions, the factors studied arranged in 6 x 2 factorial. The different levels of initial soil salinity were obtained with soils where previous crop had been cropped in a source of variation in the level of electrical conductivity (EC), caused by the addition of fertilizer in a pots. The solution electrical conductivity was measured after each irrigation event, using extractants with ceramic cups. The results showed that levels of soil salinity caused by the accumulation of fertilizer salts affected directly the variables: water use, fruit yield, dry matter production, leaf area index and plant growth. The use of extractors solution allowed to control the fertigation management, and maintain the desired levels of salinity in the soil solution during the evaluated period. It appears that the reduction in eggplant yield in greenhouse was approximately 8.65% for step of 1 dS m-1 in soil salinity, the threshold salinity was 1.71 dS m-1.

Com o monitoramento periódico da solução do solo, pode-se determinar a condutividade elétrica e a concentração de íons específicos, essenciais à nutrição das plantas. Dentre as técnicas de extração da solução do solo, o extrator de cápsula porosa destaca-se pela praticidade em campo, baixo custo, fácil manejo e boa precisão. Com isso objetivou-se estudar os efeitos de diferentes níveis de salinidade do solo sobre as variáveis fenológicas e de produção da berinjela, cultivada em vasos e em ambiente protegido, e averiguar se a manutenção da condutividade elétrica em um determinado nível promove incremento da produção, quando contrastada com o manejo tradicional da fertirrigação. Conduziu-se um estudo em ambiente protegido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,3; S2 = 2,4; S3 = 3,6; S4 = 4,5; S5 = 5,6 e S6 = 6,4 dS m-1) e dois manejos de fertirrigação: com controle da condutividade elétrica da solução do solo (M1), e o tradicional (M2), obedecendo a curva de absorção de nutrientes da cultura anteriormente estabelecida. O delineamento estatístico adotado foi o de blocos casualizados completos, com quatro repetições, ficando os fatores estudados arranjados no esquema fatorial 6 x 2. Os diferentes níveis de salinidade inicial do solo foram obtidos com solos de cultivos anteriores, no qual tinha-se como fonte de variação o nível de condutividade elétrica (CE), ocasionada pela adição de fertilizantes em ambiente protegido. A condutividade elétrica da solução foi medida após o término de cada evento de irrigação, utilizando-se extratores com cápsulas porosas. Os resultados revelaram que os níveis de salinidade do solo provenientes do acúmulo de sais fertilizantes afetou diretamente as variáveis consumo hídrico, produção de frutos, produção de matéria seca, índice de área foliar e o desenvolvimento vegetativo das plantas. O uso dos extratores de solução permitiu auxiliar o manejo da fertirrigação, mantendo os níveis desejados de salinidade da solução do solo ao longo do tempo. Verificou-se que a redução média na produção da cultura da berinjela, em estufa, foi da ordem de 8,65% para o incremento de 1 dS m-1 na salinidade do solo, acima da salinidade limiar, que foi de 1,71 dS m-1. / Periodic monitoring of soil solution allow to determine the electrical conductivity and concentration of specific ions essential to plant nutrition. Among the extraction techniques of soil solution, the porous cup extractors distinguished by their practicality in the field, low cost and good accuracy. This study has to aim to evaluate the effects of different levels of soil salinity on phenological and production of eggplant grown in pots in a greenhouse, and compare whether the control of the electrical conductivity in a certain level promotes increase the yield when compare to the traditional fertigation management . A study was conducted in a greenhouse in the Department of Biosystems Engineering, ESALQ / USP, Piracicaba, SP, Brazil. The treatments consisted of a combination of two factors: six levels of initial soil salinity (S1 = 1.3, S2 = 2.4, S3 = 3.6, S4 = 4.5, S5 = 5.6 and S6 = 6.4 dS m-1) and two fertigation management: electrical conductivity control of soil solution (M1) and traditional (M2) by following the absorption curve of nutrients from the crop previously established. The statistical design was a randomized complete block with four repetitions, the factors studied arranged in 6 x 2 factorial. The different levels of initial soil salinity were obtained with soils where previous crop had been cropped in a source of variation in the level of electrical conductivity (EC), caused by the addition of fertilizer in a pots. The solution electrical conductivity was measured after each irrigation event, using extractants with ceramic cups. The results showed that levels of soil salinity caused by the accumulation of fertilizer salts affected directly the variables: water use, fruit yield, dry matter production, leaf area index and plant growth. The use of extractors solution allowed to control the fertigation management, and maintain the desired levels of salinity in the soil solution during the evaluated period. It appears that the reduction in eggplant yield in greenhouse was approximately 8.65% for step of 1 dS m-1 in soil salinity, the threshold salinity was 1.71 dS m-1.

The two-spotted spider mite (TSM), Tetranychus urticae Koch, is an important pest of many greenhouse and field crops worldwide. The development of resistance in TSM populations to chemical acaricides, allied with public health concerns about pesticide residues, has motivated the search for alternative control measures to suppress the pest. Hyphomycetous fungi are promising agents for mite control and the fungus Beauveria bassiana (Bb) (Balsamo) Vuillemin was investigated in this study as a biocontrol agent. The principal objectives of this study comprised: a) screening Bb strains for their pathogenicity against T. urticae; b) testing the effect of adjuvants on the efficacy of Bb; c) studying the effect of plant type on persistence of Bb and the efficacy of control of Bb against T. urticae; d) evaluating the field efficacy of Bb applications against T. urticae; e) testing the compatibility of Bb with selected fungicides; and f) assessing the synergy between Bb and soluble silicon for T. urticae control. Screening bioassays of sixty-two strains of Bb identified the two most effective strains, PPRI 7315 (R289) and PPRI 7861 (R444), that caused mortality levels of more than 80% of adult mites at 9 d post-inoculation with 2 × 108 conidia ml-1. These strains performed significantly better than the Bb commercial strain PPRI 5339, in laboratory bioassays. The two strains also attacked mite eggs, causing 53.4% and 55.5% reduction in egg hatchability at 2 × 108 conidia ml-1 respectively. However, PPRI 7861 showed relatively higher production of conidia in culture and was, therefore, selected for further trials under greenhouse and field conditions. Greenhouse evaluations of the effects of two adjuvants (Break-thru® and a paraffin oil-based emulsion) on efficacy of Bb demonstrated a higher efficacy of the biocontrol agent (BCA) when it was applied with Break-thru® or the oil solution than with water alone. Moreover, Bb conidia applied in Break-thru® solution resulted in greater control of TSM than conidia applied in the mineral oil. There was also a dose-response effect and the control of TSM by Bb increased when the concentration of conidia was increased. The control of TSM by Bb in beans (Phaseolus vulgaris L), cucumber (Cucumis sativus L.), eggplant (Solanum melongena L.), maize (Zea mays L.) and tomato (Solanum lycopersicum L.) was tested in greenhouse trials. On these crops, the persistence of conidia declined over time. The rate of decline was significantly higher on maize. However, TSM mortality was positively correlated with the amount of conidia deposited on leaves immediately after spraying, rather than their persistence over time. Higher levels of mortality of TSM due to Bb application were observed on beans, cucumber and eggplants, suggesting that the type of crop must be taken into consideration when Bb is applied as a BCA. Field efficacy of Bb against mites was evaluated in two trials on eggplants. Based on assessment of population densities of mites and leaf damage assessments; both trials showed that the strain PPRI 7861 controlled TSM in the field. Two commonly used fungicides, azoxystrobin and flutriafol, were investigated in vitro tests on culture medium and laboratory bioassays on detached bean leaves (Phaseolus vulgaris L.) for their effects on Bb. Azoxystrobin (a strobilurin) was less harmful to Bb while flutriafol was found to be inhibitory. Another important finding of this study was the substantial enhancement of Bb efficacy by soluble silicon. When Bb was combined with soluble Si, the control of TSM was better than when either of the two products was applied alone. Moreover, application of soluble Si as a plant fertilizer in hydroponic water nutrient increased accumulation of peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase enzymes in leaves of plants infested with TSM. Increased activity of these defense enzymes in leaves deters feeding behaviour of mites. We suggested that feeding stress renders them susceptible to Bb infection, which would explain the synergy observed between the two agents. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Text in English with abstracts in English, Tsonga and Sepedi and keywords in English / This study was carried out to investigate the performance and quality of Cucumis metuliferus E. Mey. Ex Naudin (African horned cucumber) under protected and open environment with the aim of comparing yield and quality for the purpose of commercialisation of the crop. Therefore, the overall objective was to determine a suitable growing environment for C. metuliferus between greenhouse, shade net and open field, so that a comparative yield and quality analysis could be done for the purpose of commercialisation of the crop. Cucumis metuliferus seeds are difficult to germinate under the normal suitable environmental conditions in which most farmers operate. Germination was evaluated with respect to growth medium, scarification and seed certification. These factors ultimately control yield and fruit quality. The main aim of the study was to investigate the effect or impact of seed certification, growth medium (sand and vermiculite, peat TS1 and seedling mix) and scarification on germination success of C. metuliferus seeds. The seeds were classified under four different categories viz. treated certified, non-treated certified, treated uncertified, and non-treated uncertified. Of the 540 certified and uncertified seeds sown in the three-growth media, 80% germinated, significantly more that those that failed. The treatment combination of treated certified seeds (TC) and peat demonstrated high germination success rate of 93.6%, followed by the treatment combination of treated certified seeds (TC) and sand+ vermiculite with germination success rate of 91.3%. The treatment combination of uncertified untreated (UTU) seeds and potting mix illustrated low germination success rate at 37.2%. In general, the study results revealed that certified seeds scarified with warm water combined had a higher germination rate that unscarified seeds, irrespective of the growth media. Since the seedling root-ball integrity is essential for transplant survival, this study suggests peat and certified seeds as the best combination for propagation and good quality plants. Water scarcity, population growth and climate change are the major factors affecting agricultural productivity in the 20th century. Cucumis metuliferus grows naturally in the wild; however, its yield response to water stress, different cultivation environment and soil types, has not been assessed. A study was carried out to determine water use efficiency of the C. metuliferus grown the greenhouse, shade net and open field under varying soil types and irrigation water levels, so that a comparative analysis could be done on productivity levels. The research was conducted at the University of South Africa (Unisa) Science Campus, in Florida, Gauteng (-26.157831 S, 27.903364 E) during the 2017/2018 and 2018/2019 growing seasons. A factorial experiment with two factors – soil (loamy soil and sandy loam soil) and water stress levels (no water stress, moderate water stress and severe water stress). The pot experiments were a completely randomised design with nine (9) replicates per treatment. Data collected included total biomass, aboveground biomass, harvest index and water use efficiency. Results illustrated that treatment of moderate water stress combined with loamy soil and shade net decreased WUE from 6.2 to 1.4 kg m-3, whereas treatment combination of no water stress combined with sandy loam and open field environment demonstrated increase in WUE from 1.4 to 6.2 kg m-3. Nutritional concentration of most crops depends on factors such as amount of water, growing environment, light intensity and soil types. However, factors influencing nutritional concentration of C. metuliferus fruits is not yet known. Another objective of the study was to determine the effect of different water stress levels, soil types and growing environment (greenhouse, shade net and open field) on the concentration of nutrients in C. metuliferus fruit. Freeze-dried fruit samples were used in the quantification of ꞵ-carotene, vitamin C, vitamin E, total soluble sugars, crude proteins, total flavonoids, total phenols, macro-nutrients (Ca, Mg, P, K, Na and S), and micro-nutrients (Cu, Fe, Mn and Zn). Results demonstrated that plants grown under shade net, combined with severe water stress level and loamy soil, had increased total soluble sugars (15.8 ˚Brix) compared to other treatments. Plants under shade net environment, combined with moderate water level and loamy soil, resulted in increased crude protein content (6.31 ˚Brix). The severe water stress treatment combined with loamy soil under greenhouse conditions resulted in increased ꞵ-carotene content (1.65 mg 100 g-1 DW) when compared to other treatments. Regarding vitamin C, the treatment of no water stress combined with loamy soil under shade net environment showed higher content of (33.1 mg 100 g-1 DW). The severe water stress treatment combined with sandy loam soil under greenhouse environment, increased vitamin E content (35.1 mg 100 g-1 DW) when compared to other treatments. The treatment of open field under severe water stress level and loamy soil increased total flavonoids content (0.85 mg CE/g-1 DW) in the fruit when compared to other treatments. The results thus imply that this plant bears better-quality fruit in terms of concentration of nutrients and biochemical constituents when grown under no to moderate water stress treatment on the loamy or sandy loam substrate in the shade net and open field environment. Primary metabolites are biological compounds that are essential to the growth and development of a plant during its life cycle. They have a direct impact on the yield and biochemical constituents in plants. Quantities of the primary metabolites were determined using the LC-MS-8040 triple quadrupole mass spectrometer (Shimadzu) from fruits harvested from treatments mentioned above. The results showed that the no water stress treatment combined with sandy loam under shade net environment significantly (P≤0.05) increased asparagine content from 10×106 to 80x106 peak intensity when compared to other treatments. The severe water stress treatment combined with sandy loam soil under open field environment during the 2017/2018 season, significantly increased dopa content from 12,030 to 324,240 peak intensity, while during the 2018/2019 season, 4-hydroxyproline from 10×106 to 90x106 peak intensity the was significantly increased. The study suggests that the treatment combination of water stress levels (no water stress and severe water stress) and soil substrates (loamy soil and sandy loam) under greenhouse and shade net significantly affected the shift of primary metabolites profile of C. metuliferus fruit as opposed to individual factors, respectively. There is therefore great potential to commercialise this crop; however, there is still a great deal that is not well understood of its growth habits and biological/biochemical constituents as a future alternative crop. / Ndzavisiso lowu wu endliwe ku lavisisa hi matirhelo na khwaliti ya Cucumis metuliferus E. Mey. Ex Naudin (African horned cucumber) eka mimbangu na mavala lama sirheleriweke na hi xikongomelo xa ku kotlanisa ntshovelo na vuxopaxopi bya khwaliti hi xikongomelo xa ku endla minxaviso ya ximila. Xikongomelonkulu xa ku vona ku faneleka ku kula ka C. metuliferus exikarhi ka ti-greenhouse, nete ya ndzhuti na mimbangu ya le rivaleni ku endlela ku pfuneta nxopaxopo. Timbewu ta C. metuliferus ta nonon'hwa ku tihlukisa ehansi ka swiyimo swa mbangu leswi faneleke laha varimi va tirhaku eka tona. Ku hlukisa swi kamberiwe hi ku langutana na midiyamu ya ku kula, skarifikhexini na switifiketi swa timbewu. Swilo leswi swi lawula ntshovelo na khwaliti ya muhandzu. Xikongomelonkulu xa ndzavisiso lowu a ku ri ku lavisa hi vuyelo bya ku nyikiwa ka switifiketi, midiyamu ya ku kula (sand + vermiculite, peat TS1 and seedling mix) na skarifikhexini eka ku humelela ku hlukisa timbewu ta C. metuliferus E. Mey. ex naudin. Timbewu ti klasifayiwile ehansi ka tikhathegori ta mune to hambana, ku nga, treated certified, non-treated certified, treated uncertified, na non-treated uncertified.Hi vunharhu ka timediya leti ti ve na nhlukiso wa xiyenge hi 80%. Vuyelo byi kombise leswo treated certified na non-treated certified ti ve na ku humelela ka le henhla ka nhlukiso hi 93.6% na 91.3% hi ku landzelelana. Vuhumeleri bya nhlukiso wa le hansi ku ve timbewu ta treated uncertified hi vuyelo bya 37%. Vulehi bya 12 cm byi voniwe eka certified seedlings tanihi bya le henhla swinene. Swimilani swa unscarified na swa uncertified swi ve na timbewu ta le hansi, ta vulehi bya 3.44 cm eka vhiki ra vumune. Hikokwalaho, seed certification swi ve na vuyelo ngopfu ku tlula scarification hi majini ya le henhla swinene. Ku khomaniseka ka ximila eka bolo ya misava i swa nkoka eka ku pona no ya emahlweni ka ximila loko xi transplantiwa, kasi ndzavisiso lowu wu tlakusa leswo ku va na peat na timbewu leti nga na switifiketi tanihi ndlela yo antswa swinene ya ku kurisa swimila na ku va na swimila swa khwaliti. Ku pfumaleka ka mati, nkulo wa swilo hinkwaswo na ku cinca ka tlayimete i swa nkoka leswi khumbaka ku tirheka ka vurimi eka malembexidzana ya 20. Cucumis metuliferus yi kula hi ntumbuluko enhoveni; kambe ntshovelo wa yona wu angula eka ku kala ka mati, tindhawu to hambana ta ku rimiwa na mixaka ya misava, a swi si kamberiwa. Ku endliwe ndzavisiso ku vona ku faneleka ka mafambiselo ya ku kurisa ximila eka greenhouse, nete ya ndzhuti eka swiyimo swa mavala lama pfulekeke, leswo nxopaxopo wu ta kotlanisiwa eka tilevhele ta vuyelo bya ntshovelo loku nga endliwaka. Ndzavisiso wu endliwe eka greenhouse, nete ya ndzhuti na swiyimo swa mavala lama pfulekeke eKhempasi ya Sayense eUniversity of South Africa (Unisa) eFlorida, eGauteng (26.157831 S, 27.903364 E) hi nkarhi wa 2017/2018 na 2018/2019 hi tisizini ta ku byala. Ekspirimente leyi nga na swilo swimbirhi – ku nga misava ya loamy na misava ya misava ya sava ya loam) na levhele ya ncheleto wa mati (laha ku nga ri ku na mati kahle, laha ku nga na matinyana na laha ku kalaka mati). Xipirimente xa le mapotweni xi endliwe hi ndlela yo ka yi nga kunguhatiwangi hi ku tirhisa ku phindaphinda ka nkaye (9), na dizayini ya kona leyi nga kombisiwa laha henhla. Tipharamita ta ku pimiwa ti katsa chlorophyll content, stomatal conductance na xiyenge xa ntshovelo, xo fana na ku tirhisa mati, vuheleri bya biomass, biomass ehenhla ka bayomasi ya misava, indeksi ya ntshovelo, vulehi bya muhandzu, nhlayo ya mihandzu, na ku tirhisiwa ka mati hi ndlela yo hlayisa. Vuyelo byi kombise leswo tirhelo ra mavala lama pfulekeke swi pfanganisiwa na ndhawu yo kala mati na misava ya sava ya loam, swi ngetela nhlayo ya mihandzu. Ku tirhiwa ka swiyimo swa mavala lama nga pfuleka, swi hlanganisiwa na ndhawu yo kalanyana mati na misava ya sava ya loam, swi kombise ku tirhisiwa kahle ka mati ka le henhla hi (6. 2 kg m-3) loko swi kotlanisiwa na ku tirhiwa ku n'wana. I swa nkoka ku lemuka leswaku a ku va ngi na ku hambana ku kulu exikarhi ka misava ya sava ya loam na misava ya loam eka ntirhiso wa mati lowu ku nga water use efficiency (WUE). Kambe, misava ya sava ya loam yi kombise xiyenge xa le henhla xa WUE loko swi kotlangisiwa na misava ya loam. Hikokwalaho ku nga fikeleriwa eka mhaka ya leswo ku pfanganisa ku tirhana na mavala yo pfuleka, tilevhele ta ncheleto wa mati (kahle na le xikarhi) na misava ya sava ya loam swa bumabumeriwa eka varimi leswo ku ta fikelekeleriwa xiyenge xa le henhla xa WUE na ku humelela ka ntshovelo wa C. metuliferus. Ku hlengeletana ka tinutriyente eka ndhawu yin'we (nutritional concentration) ka swimila swi titshege hi swilo swo fana na leswi kumekaka eka mati, mbangu wa ku kula, masana ya dyambu na mixaka ya misava. Kambe, swilo swo fana na ku hlengeletana ka tinutriyente ta mihandu ya C. metuliferus a swi si tiveka. Xikongomelo xa ndzhavisiso a ku ri ku vona vuyelo bya tilevhele to hambana ta ku kala ka mati (ku pfumaleka ka mati, ku pfumalekanyana, na ku pfumaleka swinene ka mati), mixaka ya misava (misava ya loam na misava ya sava) mbangu wa ku kula (greenhouse, nete ya ndzhuti na mavala yo pfuleka) hi ku pfangana na tinutriyente eka mihandzu ya C. metuliferus E. Mey. ex naudin. Tisampuli ta mihandzu leyi nga omisiwa yi friziwa ti tirhisiwe eka ku endla vunyingi bya ꞵ-carotene, Vhitamini C, Vhitamini E, na total soluble sugars, ti-crude protein na ti-total flavonoids, total phenols, na micro-nutrients (Cu, Fe, Mn na Zn). Vuyelo bya ndzavisiso byi kombise leswo swimila leswi nga kurisiwa eka nete ya ndzhuti, swi pfanganisiwa na levhele ya nkalo wa mati swinene na misava ya loam, swi ngetele ti-soluble sugars hi (15.8 ˚Brix) loko ku kotlanisiwa na ku tirhiwa kun'wana. Swimila leswi nga hansi ka mbangu wa nete ya ndzhuti, swi pfanganisiwa na nkayivelonyana wa mati hi vuxikarhi na misava ya loam, swi ve na vuyelo bya ku ngetela crude protein content hi (6.31˚Brix). Ku tirhiwa ka nkayivelo wa mati swinene swi pfanganisiwa na misava ya loam ehansi ka swiyimo swa greenhouse swi ngetelele ꞵ-carotene content (1.65 mg/100 g-1 DW) loko swi kotlanisiwa na ku tirhiwa kun'wana. Ku tirhiwa ka ku kayivela ka mati swi pfanganisiwa na misava ya loam ehansi ka mbangu wa nete ya ndzhuti swi kombise ku ngeteleleka ka vhitamini C hi (33.1 mg 100 g-1 DW). Ku tirhiwa ka nkayivelo wa mati swinene swi pfanganisiwa na misava ya loam ehansi ka swiyimo swa mbangu wa greenhouse swi ngetelele vhitamin E hi (35.1 mg 100 g-1 DW) loko swi kotlanisiwa na ku tirhiwa kun'wana. Ku tirhiwa ka mavala lama nga rivaleni eha CE g-1 DW) loko swi kotlanisiwa na ku tirhiwa kun'wana. Ku tirhana na nkayivela mati ka levhela ya le xikarhi na misava ya sava ya loam ehansi ka mbangu wa nete ya ndzhuti swi kombise ku ngeteleleka ka Zn content (12.7 μg g-1 DW) loko swi kotlanisiwa na ku tirhiwa kun'wana. Vuyelo byi kombisa leswaku ximila lexi xi na mihandzu ya khwaliti yo antswa hi ku landza ku hlengeletana ka tinutriyeente na tikhonstituwenti ta bayokhemikali, loko xi kurisiwa ehansi na ku ka ku nga ri na nkayivela mati kumbe ku kayivelanyana ka mati, hi ku tirhisa misava ya loam kumbe misava ya sava eka nete ya ndzhuti na le ka mavala ya le rivaleni.Ti-primary betabolites ti tlhela titiviwa tanihi biological compounds leti ti faneleke eka ku kula na ku hluvuka ka ximila hi nkarhi wa vutomi bya xona. Ti na vuyelo byo kongoma eka ntshovelo na tikhonsticuwenti ta bayokhemikala eka swimila. Vunyingi bya primary metabolites swi vekiwe hi ku tirhisa LC-MS-8040 triple quadrupole mass spectrometer (Shimadzu) eka mihandzu leyi nga ntshovelo wa ku tirhiwa kun'wana loku ku nga vuriwa laha henhla. Vuyelo byi kombe leswo ku tirhana na nkala nkayivelo wa mati, swi pfanganisiwa na misava ya loam ehansi ka mbangu wa nete ya ndzhuti, swi ngetelele swinene asparagine content from 10×106 to 80x106 nsi ka nkayivelo swinene wa mati na misava ya loam, swi ngetelele ti-total mz loko swi kotlangisiwa na ku tirhiwa kun'wana. Ku tirhana na nkayivelo wa mati swinene, swi pfanganisiwa na misava ya sava ya loam ehansi ka mbangu wa mavala lama pfulekeke hi nkarhi wa sizini ya 2017/2018, swi ngetelele swinene dopa content ku suka eka 12,030 to 324,240 peak intensity, kasi hi nkarhi wa sizini ya 2018/2019 season, 4-hydroxyproline ku 10×106 to 90x106 peak intensity swi ngeteleleke swinene. Ku tirhana ko fanana ehansi ka mbangu wa greenhouse, swi ngetelele swinene acetylcarnitine content ku suka eka 3,761 to 82,841 area under the curve hi nkarhi wa sizini ya 2018/2019. Ku tirhiwa ka ku nga ri na ku kayivela ka mati ka le xikarhi swi pfanganisiwa na misava ya loam ehansi ka mbangu wa mavala lama nga rivaleni swi ngetelele swinene norepinephrine content from 71,577 to 256,1045 peak intensity. Ndzavisiso wu pimanyete leswo mpfanganyiso wa ku tirhana na tilevhele ta ncheleteo wa mati (laha ku nga ri ku na ku kayivela ka mati na le ku nga na nkayivelo wa mati) na misava ya loam na misava ya sava ya loam) ehansi ka greenhouse na nete ya ndzhuti swi khumbe swinene ku xifta ka mihandzu ya primary metabolites profile of C. metuliferus E. Mey. ex naudin loko ku langutaniwa na tifekthara ha yin'we yin'we hi ku landzelelana.flavonoids content (0.85 mg CE g-1 DW) loko swi kotlanisiwa na ku tirhiwa kun'wana. Ku tirhana na nkayivela mati ka levhela ya le xikarhi na misava ya sava ya loam ehansi ka mbangu wa nete ya ndzhuti swi kombise ku ngeteleleka ka Zn content (12.7 μg g-1 DW) loko swi kotlanisiwa na ku tirhiwa kun'wana. Vuyelo byi kombisa leswaku ximila lexi xi na mihandzu ya khwaliti yo antswa hi ku landza ku hlengeletana ka tinutriyeente na tikhonstituwenti ta bayokhemikali, loko xi kurisiwa ehansi na ku ka ku nga ri na nkayivela mati kumbe ku kayivelanyana ka mati, hi ku tirhisa misava ya loam kumbe misava ya sava eka nete ya ndzhuti na le ka mavala ya le rivaleni.Ti-primary betabolites ti tlhela titiviwa tanihi biological compounds leti ti faneleke eka ku kula na ku hluvuka ka ximila hi nkarhi wa vutomi bya xona. Ti na vuyelo byo kongoma eka ntshovelo na tikhonsticuwenti ta bayokhemikala eka swimila. Vunyingi bya primary metabolites swi vekiwe hi ku tirhisa LC-MS-8040 triple quadrupole mass spectrometer (Shimadzu) eka mihandzu leyi nga ntshovelo wa ku tirhiwa kun'wana loku ku nga vuriwa laha henhla. Vuyelo byi kombe leswo ku tirhana na nkala nkayivelo wa mati, swi pfanganisiwa na misava ya loam ehansi ka mbangu wa nete ya ndzhuti, swi ngetelele swinene asparagine content from 10×106 to 80x106 mz loko swi kotlangisiwa na ku tirhiwa kun'wana. Ku tirhana na nkayivelo wa mati swinene, swi pfanganisiwa na misava ya sava ya loam ehansi ka mbangu wa mavala lama pfulekeke hi nkarhi wa sizini ya 2017/2018, swi ngetelele swinene dopa content ku suka eka 12,030 to 324,240 peak intensity, kasi hi nkarhi wa sizini ya 2018/2019 season, 4-hydroxyproline ku 10×106 to 90x106 peak intensity swi ngeteleleke swinene. Ku tirhana ko fanana ehansi ka mbangu wa greenhouse, swi ngetelele swinene acetylcarnitine content ku suka eka 3,761 to 82,841 area under the curve hi nkarhi wa sizini ya 2018/2019. Ku tirhiwa ka ku nga ri na ku kayivela ka mati ka le xikarhi swi pfanganisiwa na misava ya loam ehansi ka mbangu wa mavala lama nga rivaleni swi ngetelele swinene norepinephrine content from 71,577 to 256,1045 peak intensity. Ndzavisiso wu pimanyete leswo mpfanganyiso wa ku tirhana na tilevhele ta ncheleteo wa mati (laha ku nga ri ku na ku kayivela ka mati na le ku nga na nkayivelo wa mati) na misava ya loam na misava ya sava ya loam) ehansi ka greenhouse na nete ya ndzhuti swi khumbe swinene ku xifta ka mihandzu ya primary metabolites profile of C. metuliferus E. Mey. ex naudin loko ku langutaniwa na tifekthara ha yin'we yin'we hi ku landzelelana. / Thuto ye e dirilwe ka maikemišetšo a go nyakišiša tiragatšo le boleng bja Cucumis metuliferus E. Mey. Ex Naudin (phara ya seAfrika) mo tikologong yeo e šireleditšwego le ya mo lebaleng e le nepo ya go bapetša tshekatsheko ya kotollu le boleng go hola thekišo ya mabele. Maikemišetšo kakaretšo e le go humana tsela ya maleba ya go mediša C. Metuliferus dipakeng tša mokhukhutšhireletšo, nnete ya moriti le mo ditikologong tša mabala ao a bulegilego gore go nolofatšwe tshekatsheko. Go boima go mediša dipeu tša C. Metuliferus ka tlase ga maemo a tikologo ya maleba ya go tlwaelega yeo e šomišwago ke bontši bja balemi. Medišo ya dipeu e lekanyeditšwe go ya le ka sedirišwa sa go mediša dimela, go fala dipeu le go hlahlobo ya boleng bja dipeu. Dikokwana tše ke tšona di laolago kotollu le boleng bja dienywa. Nepokgolo ya thuto ye e be e le go nyakišiša khuetšo ya tlhahlobo ya polokego ya dipeu tše, sedirišwa sa go mediša dimela (mohlaba+vermiculite, peat TS1 le motswako wa dipeu) le phalo ya dipeu go kgonthišiša katlego ya go mela ga dipeu tša C. Metuliferus. Dipeu di ile tša arolwa go ya le ka magoro a mane, bjalo ka peu ya go okobatšwa ka dikhemikhale yeo e hlahlobilwego, peu yeo e sa okobatšwago gomme e hlahlobilwe, peu ya go okobatšwa e sa hlahlobjwago le peu yeo e sa okobatšwago gomme e se ya hlahlobjwa. Boraro bja didirišwa tše di laeditše katlego ya go mediša yeo e ka balelwago go 80%. Dipoelo di šupa gore dipeu tšeo di okobaditšwego di se a hlahlobjwa le tšeo di sa okobatšwago di hlahlobilwe di bile le katlego ya tlhogo yeo e ka balelwago go 93.6% le 91.3%. Tlhogo ya fase e bile go dipeu tšeo di okobaditšwego di sa hlahlobjwago ka poelo ya 37%. Dipeu tše di hlahlobilwego di laeditše botelele bja 12cm gomme e le bjona bja go di feta ka moka. Dipeu tšeo di sa falwago le go hlahlobjwa di bile le botelele bja fase bja go balelwa go 3.44 cm ka dibeke tše nne. Bjalo, tlhahlobo ya dipeu e tlišitše katlego go fetiša phalo. Ka ge mudu wa dipeu o le bohlokwa go tšhutišetšo ya maphelo a dimela, thuto ye e thekga mmutedi le tlhahlobo ya dipeu bjalo ka tlhakanyo ya go mediša dimela tša boleng bja maleba. Tlhokego ya meetse, go oketšega ga baagi, le diphetogo tša klaemete ke tšona dikokwana tše di amago tšwelelo go tša temo nakong ya bjale. C. Metuliferus E. Mey. ex naudin e mela ka lešokeng tlhagong ya yona; efela, kotullo ya yona go tlhokego ya meetse, go mehuta ya mašemo le mehuta ya mabu ga se e ahlaahlwe. Thuto e ile ya dirwa go humana mokgwa wa go bjala/mediša dimela dipakeng tša mokhukhutšhireletšo, nnete ya moriti le boemo bja lebala le le bulegilego, gore go tle go tšweletšwe tshekatsheko yeo e laetšago diphapano tša mabato a puno. Nyakišišo ye e diritšwe ka fase ga maemo a mokhukhutšhireletšo, nnete ya moriti le lebaleng le le bulegilego Yunibesithing ya Afrika Borwa (UNISA) Khamphasing ya tša Saense, go la Florida, Gauteng (-26.157831 S, 27.903364 E) ka nako ya sehla sa 2017/2018 le 2018/2019 ka dinako tša go mela. Teko ye e ithekgile godimo ga dikokwana tše pedi – mabu (monola le mohlaba) le mabato a taolo ya go nošetša (tlhokego ya meetse ya lebato la fase, tlhokego ya meetse ye e lekanetšego le tlhokego ya meetse ya lebato la godimo). Diteko di be di beilwe ka mokgwa wo o sa rulaganywago gomme teko ye nngwe le ye nngwe e boeleditšwe ga senyane (9) bjalo ka ge e laeditšwe godimo. Dipharametha tšeo di lekantšwego di akaretša dikagare tša chlorophyll, stomatal conductance le bjalo ka tšhomišo ya meetse, palomoka ya dimela, dimela tše di bonagalago ka godimo, lenaneo la puno, botelele bja enywa, palo ya enywa le tšhomišo ya meetse ke dimela. Dipoelo di tšweletša gore teko ya mo lebaleng le le bulegilego le meetse a a lekanetšego gammogo le monola di oketša palo ya dienywa. Teko ya mo lebaleng le le bulegilego go kopantšhwa le meetse ao a lekanetšego le monola, di laeditše tšhomišo ya meetse yeo e balelwago go (6.2 kg m-3) ge go bapetšwa le diteko tše di ngwe. Go bohlokwa go lemoga gore ga ga go na diphapano magareng ga mohlaba le monola tšhomišong ya meetse (WUE). Efela, mohlaba o laeditše (WUE) ya godimo ge go bapetšwa le monola. Se se bolela gore, go ka tšewa sephetho sa gore teko ya dipeu lebaleng le le bulegilego, taolo ya go nošetša dimela (ye gabotse le ye e lekanetšego) le mohlaba ke didirišwa tšeo go eletšwago balemi gore ba di šomiše go humana (WUE) ya godimo le tšweletšo ye e atlegilego ya C. metuliferus. Bontši bja phepo mo mabeleng bo hlohleletšwa ke dikokwana tša go swana le meetse, tikologo ya mo a melago gona, dihlase tša letšatši le mehuta ya mabu. Efela, dikokwana tše di huetšago bontši bja diphepo go dienywa tša C. metuliferus ga dišo di tsebjwa. Nepo ya thuto ye e be e le go nyakolla khuetšo yeo dikokwana tše di latelago; di nago le yona go bontši bja diphepo go enywa ya C. Metuliferus: mabato a meetse (tlhokego ya meetse ya lebato la fase, tlhokego ya meetse ye e lekanetšego le tlhokego ya godimo ya meetse), mehuta ya mabu (monola le mohlaba) le tikologo ya go mediša (mokhukhutšhireletšo, nnete ya moriti le lebala le le bulegilego). Diteko tša enywa yeo e omišitšwego ka setšidifatšing e ile ya šomišwa go tšweletša boleng bja ꞵ-carotene, vitamin C, vitamin E, total soluble sugars, crude proteins, total flavonoids, total phenols, le micro-nutrients (Cu, Fe, Mn le Zn). Dipoelo di šupa gore dimela tše di godišitšwego ka fase ga nnete ya moriti, go akaretša le tlhokego ya meetse ya godimo le monola di nyološitše diswikiri tše di humanegago mo dimeleng (15.8 ˚Brix) ge go bapetšwa le diteko tše dingwe. Dimela tikologong ya nnete ya moriti go akaretša le tlhokego ya meetse ye e lekanetšego le monola di ile tša nyološa phroteine (6.31 ˚Brix). Teko go tlhokego ya meetse ya godimo go akaretša le monola ka tlase ga boemo bja mokhukhutšhireletšo go nyološitše diteng tša ꞵ-carotene (1.65 mg 100 g-1 DW) ge e bapetšwa le diteko tše dingwe. Teko go tlhokego ya meetse go akaretša monola ka fase ga nnete ya moriti go nyološitše Vitamin C (33.1 mg100 g-1 DW). Teko go hlokego ya meetse ya godimo go akaretša mohlaba tikologong ya mokhukhutšhireletši go nyološitše diteng tša vitamin E (35.1 mg/100 g-1 DW) ge e bapetšwa le diteko tše dingwe. Teko ya go se hlokege ga meetse, go akaretša le monola tikologong ya lebala le le bulegilego e nyološitše palomoka ya diteng tša phenolic (6.4 mg GAE/g-1 DW) ge e bapetšwa le diteko tše dingwe. Teko lebala le le bulegilego ka fase ga hlokego ya meetse ye godimo go akaretša monola go okeditše diteng tša flavonoids (0.85 mg CE g-1 DW) mo dienyweng tša gona ge e bapetšwa le diteko tše dingwe. Teko go hlokego ya meetse ye e lekanetšego le mohlaba ka fase ga nnete ya moriti di laeditše go oketšega ga diteng tša Zn (12.7 μg g-1 DW) ge e bapetšwa le diteko tše dingwe. Dipoelo di laetša gore semela se se thunya boleng bjo bo kgodišago bja dienywa ge go lebeletšwe bontši bja diphepo le dikokwana tša dikhemikhale ge di medišwa mo go sa hlokegago meetse go yela go mo go hlokegago meetse ka go lekanela, go šomišitšwe monola goba mohlaba mo nneteng ya moriti le mo lebaleng le le bulegilego. Dimetabolite tša motheo di tsebjwa bjalo ka motswako wa tlhago wo o lego bohlokwa go kgolo le tlhabollo ya dimela maphelong a tšona. Di na le khuetšothwii go dikokwana tša puno le khemikhale ya hlago ya dimela. Bontši bja dimetabolites tša motheo di humanwe ka go šomiša LC-MS-8040 triple quadrupole mass spectrometer (Shimadzu) ya go tšwa dienyweng tšeo di bunnwego ditekong tše di šetšego di boletšwe. Dipoelo di laeditše gore teko ya hlokego ya meetse ya lebato la fase go akaretša le mohlaba tikologong ya nnete ya moriti; e nyološitše asparagine content go tloga go 10×106 go ya go 80x106 peak intensity ge e bapetšwa le diteko tše dingwe. Tlhokego ya meetse ya lebato la fase e akaretša le monola tikologong ya lebala le le bulegilego ka nako ya sehla sa 2017/2018, 4-hydroxyproline go tšwa go 10×106 go ya go 90x106 area under curve e ile ya nyušwa. Teko ya go swana le ye tikologong ya mokhukhutšhireletšo e ile ya oketša dikagare tša acetylcarnitine go tšwa go 3,761 go ya go 82, 841 peak intensity ka nako ya sehla sa 2018/2019. Teko go tlhokego ya meetse ye e lekanetšego go akaretšwa le monola tikologong ya lebala le le bulegilego e nyološitše dikagare tša norepinephrine go tloga go 71,577 go ya go 256,1045 peak intensity. Diteko di šupa gore ge go kopantšwe taolo ya mabato a go nušetša (tlhokego ya meetse ya lebato la fase le tlhokego ya meetse ya lebato la godimo) le (monola le mohlaba) ka fase ga boemo bja mokhukhutšhireletšo le nnete ya moriti go ile gwa ama katološo ya dimetabolites tša motheo tša enywa ya C. metuliferus ge di bapetšwa le kokwana ye nngwe le nngwe. / College of Agriculture and Environmental Sciences / Ph. D. (Agriculture)