Sweetpotato (Ipomoea batatas) is a major staple food in Africa and the rest of the world where they are discovered to be a good source of carbohydrates, vitamin A, vitamin C and protein. The maximum production potential of the crop is being hampered by severe drought which ravages most parts of Africa. The main aim of this project therefore is to screen collected accessions of sweetpotatofor drought tolerance in a quick screening method with a view to identify cultivars that can perform well under water stress conditions. Fifty selected sweetpotato accessions consisting of cultivars and breeding lines collected from the ARC-VOPI gene bank were planted for drought screening in the glass house for 6 weeks during which water was withheld to induce stress. Observations were made on number of dead plants and days to wilting point, the results were analyzed and 12 best performing cultivars were selected for field trials. The field trial was carried out in Lwamondo, Thohoyandou for 6months under rain-fed conditions. The experiment was conducted in a complete randomized block design with 6 replicates.Yield data and growth parameters were collected every 8 weeks during the trial period and the data collected was analyzed using ANOVA. The best performing cultivars were Zapallo, Tacna, Ejumula, 2004-9-2 and Ndou. They were therefore recommended for further evaluation in other drought prone areas of the country. / Agriculture and  Animal Health / M. Sc. (Agriculture)

Made available in DSpace on 2018-06-27T19:13:04Z (GMT). No. of bitstreams: 2 Lauren Darold Brum.pdf: 3026080 bytes, checksum: 12591d0caef98110145691e59fa97e94 (MD5) Lauren Darold Brum.pdf.jpg: 3624 bytes, checksum: 46b9095f31a06a4e707b1804038dad51 (MD5) Previous issue date: 2013-05-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research aims to analyze errors made by students in the 8th grade of elementary school in solving algebraic questions. Specific objectives are: a) analyze the types of errors made by students of 8th grade in solving algebraic questions b) to test teaching strategies drawn from the errors made by students using the Hot Potatoes software. The research is qualitative and took place in three stages. The first stage was developed in a public school in the city of Tupanciretã, with the participation of 23 students from 8th grade, to which was applied a test with questions on algebra. The second stage took place in a private school in the same county, with 10 students, also of 8th grade, applying the same test. In the third stage, we tested activities to overcome the errors, using the Hot Potatoes software. The literature review listed elements of: Algebra and its teaching, the National Curriculum Parameters and textbooks, error analysis and the use of technology in mathematics teaching. From the data collected, it was noticed that students come to the final series of elementary school with many difficulties in algebra, in particular on the distributive property of an operation and generalization of patterns. As a suggestion for future work related to these difficulties among students of 8th grade, we proposed a set of activities to be implemented through Hot Potatoes, comprising the product of this dissertation professional. / A presente pesquisa tem como objetivo analisar erros cometidos por estudantes de 8º ano do Ensino Fundamental na resolução de questões algébricas. Os objetivos específicos são: a) analisar os tipos de erros cometidos por estudantes de 8º ano na resolução de questões algébricas; b) testar estratégia de ensino elaborada a partir dos erros cometidos pelos estudantes, com uso do software Hot Potatoes. A investigação tem caráter qualitativo e realizou-se em três etapas. A primeira etapa desenvolveu-se em uma escola pública do município de Tupanciretã, com a participação de 23 alunos de 8º ano do Ensino Fundamental, aos quais se aplicou um teste com questões sobre conteúdos de Álgebra. A segunda etapa teve lugar em uma escola privada do mesmo município, com 10 alunos, também de 8º ano, com aplicação do mesmo teste. Na terceira etapa, realizou-se a testagem de atividades para superação dos erros, usando o software Hot Potatoes. A revisão de literatura elencou elementos sobre: a Álgebra e seu ensino; os Parâmetros Curriculares Nacionais e os livros didáticos; a análise de erros; e o uso de tecnologia no ensino de Matemática. Pelos dados coletados, percebeu-se que os estudantes chegam até os anos finais do Ensino Fundamental com muitas dificuldades relativas à Álgebra, em especial quanto à propriedade distributiva de uma operação em relação a outra e à generalização de padrões. Como sugestão para futuros trabalhos relacionados a essas dificuldades encontradas entre alunos de 8º ano, propôs-se um conjunto de atividades a serem implementadas por meio do Hot Potatoes, que compõem o produto desta dissertação de mestrado profissional.

The sweet potato (Ipomoea batatas L.) is a dicotyledonous species of Convolvulaceae family, cultivated worldwide, with a low production cost and high economic return. Can be utilized in food and feed and ethanol production. The present study aimed, morphological, agronomic and biochemical characterization of sweet potato from the Active Germplasm Bank of UFS access. The experiment was conducted at the Experimental Farm " Rural Campus " UFS, located in the municipality of São Cristóvão - SE, using a randomized block design with 73 treatments (accessions of sweet potato), and two repetitions. In morpho-agronomic characterization it was found that descriptors sheet provided the variability among accessions. It was also observed that most accessions showed resistance to soil insects. The fresh and dry weight of shoots showed results ranging from 0,45 t ha-1 to 12,16 t ha-1 and 0,17 t ha-1 to 2,71 t ha-1, respectively. For total root yield variable, the values ranged from 1,20 to 10,89 t ha-1. The accessions showed excellent results for the dry root mass averaging 30,77 %. The starch content varied between 11,56 and 27,07 % , the yield of starch per hectare ranged from 0,30 to 2,39 t ha-1 and amylose content showed values between 11,57 to 32,72 %. While the ethanol yield in L ha-1 ranged from 198-1576 L h-1, the ethanol yield on L t-1 had an average of 142,67 L t-1. The results showed that the Active Germplasm Bank of UFS presents a wide phenotypic and genotypic variability, with different skills. / A batata-doce (Ipomoea batatas L.) é uma espécie dicotiledônea da família Convolvulaceae, cultivada em todo o mundo, apresentando um baixo custo de produção e retorno econômico elevado. Pode ser aproveitada na alimentação humana e animal e na produção de etanol. O presente trabalho teve como objetivo, a caracterização morfológica, agronômica e bioquímica de acessos de batata-doce do Banco Ativo de Germoplasma da UFS. O experimento foi conduzido na Fazenda Experimental Campus Rural da UFS, localizada no município de São Cristovão SE, utilizando o delineamento em blocos casualizados, com 73 tratamentos (acessos de batata-doce), e duas repetições. Na caracterização morfo-agronômica verificou-se que os descritores de folha proporcionaram a variabilidade entre os acessos. Observou-se também que a maioria dos acessos apresentou resistência a insetos de solo. A massa fresca e seca de parte aérea apresentou resultados variando de 0,45 t ha-1 a 12,16 t ha-1 e 0,17 t ha-1 a 2,71 t ha-1, respectivamente. Para a variável produtividade total de raízes, os valores variaram de 1,20 a 10,89 t ha-1. Os acessos demonstraram resultados excelentes para o teor de massa seca de raiz com média de 30,77%. O teor de amido variou entre 11,56 e 27,07%, o rendimento de amido por hectare ficou entre 0,30 a 2,39 t ha-1 e o teor de amilose apresentou valores entre 11,57 a 32,72 %. Enquanto que o rendimento de etanol em L ha-1 variou entre 198 a 1.576 L ha-1, o rendimento de etanol em L t-1 apresentou média de 142,67 L t-1. Os resultados mostraram que o Banco Ativo de Germoplasma da UFS apresenta uma grande variabilidade fenotípica e genotípica, com diferentes aptidões.

African Potato (Hypoxis hemerocallidea), (AP) is an African traditional medicine (TM) that is commonly used for various nutritional/medicinal purposes and also by people infected with the human immuno deficiency virus HIV and AIDS patients as an immune booster. The use of AP has also been recommended by the former Minister of Health of South Africa for use by HIV positive people. The main phytochemical component of AP is a norlignan glucoside, hypoxoside, and other relatively minor components have also been reported. A recent in vitro study reported the effects of AP extracts, hypoxoside and rooperol (the metabolite of hypoxoside) on human metabolic enzymes such as the cytochrome P450 (CYP450) group of enzymes and also on the transporter protein, p-glycoprotein (P-gp). This research focussed on investigating the clinical significance of those in vitro effects on the pharmacokinetics of efavirenz (EFV) in humans. EFV was chosen as the substrate drug because it is in first-line regimen of treatment of HIV/AIDS in South Africa, and also has been reported to be a substrate for the specific CYP isozymes, 3A4 and 2B6, in common with APs metabolic involvement with 3A4. A high performance liquid chromatography method with ultra-violet detection (HPLC-UV) for the quantitative determination of EFV in plasma was developed and successfully validated according to international standards with good reproducibility, accuracy, recovery, linear response and requisite sensitivity. The preparation of the plasma samples for analysis was effected by using a simple and rapid precipitation method, and the mobile phase consisted of readily available solvents. EFV in plasma samples was found to be stable under the relevant storage conditions studied. The oral dose of AP, administered as a freshly prepared traditional decoction, was standardised based on the hypoxoside content, and the quality of all the AP decoctions was analysed immediately prior to administration, using a validated HPLC-UV method. A single dose, two-phase sequential study was conducted over a period of 31 days in 10 healthy volunteers. The clinical study was approved by the Rhodes University Ethical Standards Committee, and all the participants agreed to the conditions of the study by giving their informed consent. On day 1 of the study, human subjects were administered a 600 mg EFV tablet and blood samples were collected before dosing and at various intervals over a period of 48 hr post dosing. From day 16, a traditionally prepared AP decoction was administered daily at a standardized dose of 15 mg/kg/day per subject until day 30. On day 29, volunteers were administered a single 600 mg dose of EFV as was done on day 1. Plasma samples were harvested immediately after blood sample collection and frozen at -80 ºC until assayed. Geometric mean ratios of relevant pharmacokinetic parameters, Cmax (maximum plasma concentration achieved following dosing) and AUC0-48 (area under the curve of a plot of drug plasma concentrations versus time representing the extent of absorption) of EFV before and after co-administration of 14 successive daily doses of AP were compared and evaluated to determine whether an interaction had occurred. All subjects completed the study and the geometric mean ratios of Cmax and AUC0-48 were 97.30 and 102.82 with corresponding 90% confidence intervals (CIs) of 78.81-120.14% and 89.04-118.80%, respectively. Whereas the acceptance criteria for the ratios of the AUCs fell within the preset 90% CIs indicating no interaction, the Cmax ratios fell outside the limits. Although the protocol was developed in accordance with the United States of America Food & Drug Administration’s Guidance for Drug Interactions, a priori stating that both criteria need to fall within the acceptance limits to indicate no interaction, an argument is presented to waive the Cmax requirement for the declaration of an interaction. As a result, the pharmacokinetic data generated during this study indicated that the effect of AP on the pharmacokinetics of EFV is not clinically significant. Hence, co-administration of AP is unlikely to affect the clinical use of EFV. In summary the objectives of this project were: 1. To develop and validate a suitable HPLC-UV method for the quantitative determination of EFV in plasma. 2. To perform a mini-validation of the determination of hypoxoside for use as a marker in the quality control and standardisation of AP decoctions. 3. To conduct a clinical interaction study in order to determine whether AP affects the pharmacokinetics of EFV following concurrent administration. 4. To apply the validated HPLC-UV method to determine plasma concentrations of EFV in plasma of human subjects. 5. To use appropriate statistical methods and treatments such as a non-compartmental pharmacokinetic analysis to determine the occurrence of an interaction.

Call number: LD2668 .T4 1960 P65

University of Stellenbosch. Faculty of Agrisciences. Dept. of Agronomy. / Thesis (MScAgric (Agronomy)--University of Stellenbosch, 2007. / Calcium (Ca) is an important plant nutrient with many functions, such as strengthening of cell walls and maintaining membrane stability and cell integrity. A greenhouse experiment was conducted using an aeroponic production system, to evaluate the influence of different Ca: K & Mg ratios (consisting of a control [100% Ca], and three treatments in which the Ca levels were changed to 33%, 66% and 133% of the control, while the K and Mg levels were adjusted to compensate for the change in Ca) and two different irrigation methods (irrigation on roots only, and irrigation on roots and stolons) on tuber yield and mineral concentration. The treatment that received the highest Ca: K & Mg ratio had significantly more larger tubers than the lowest Ca treatment, although there was no significant difference in total tuber number between treatments. The high Ca treatment also had a significantly higher Ca concentration in the skin than the low Ca treatment. The site of irrigation did not have a significant effect on the total tuber number per plant, or on the Ca content of the tubers that were produced. The tubers produced in the first experiment were divided into two weight classes, and stored at three different temperatures. The percentage weight loss during storage was determined by weighing the tubers before, and again after storage. The firmness of the tubers was also measured after storage. Tubers were then stored in a dark room at room temperature to allow sprouts to develop. The sprouts of each tuber were counted and weighed. Weight loss was the lowest for tubers stored at 3oC. Firmness of the tubers increased as the Ca: K & Mg ratio of the nutrient solution used during production was increased. Number of sprouts was the highest for tubers stored at 6oC. Sprout number was also significantly higher for the larger tubers compared to the smaller ones. Total sprout weight was the highest for the tubers stored at 6oC, and was also the highest for the larger tubers. After sprouts started to develop, the tubers were planted again in the greenhouse, in sawdust and irrigated with a complete Steiner nutrient solution at 1.5 mS cm-1. After these plants were harvested, the leaf area and dry weight of the leaves were determined. The first generation tubers were counted and weighed. The only factor that had a significant influence on the growth of the plants, was the size of the seed tubers that were used. The larger seed tubers produced plants that had significantly higher leaf areas, dry weight of leaves, as well as higher yields than that of the plants produced from the smaller seed tubers. From the results of this study, it can be concluded that Ca has a definite positive effect on the quality of seed potatoes as well as the size of the tubers that are produced. This study also supported that seed tubers should be stored at low temperatures, around 3oC, to maintain the highest quality, while larger tubers proved to out-yield smaller ones.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Infection of potatoes by viral pathogens causes reduced crop yield and subsequent economic loss. In South Africa Potato virus Y (PVY) and Potato leafroll virus (PLRV) are the two most destructive viruses infecting potatoes. Several other viral pathogens exist, including Potato virus X (PVX), Potato virus M (PVM), Potato virus A (PVA), Potato virus S (PVS), Potato mop-top virus (PMTV), Tomato spotted wilt virus (TSWV) and Potato spindle tuber viroid (PSTVd). Although the aforementioned pathogens are found infecting potatoes around the world, there are no published information pertaining to the prevalence of these viral agents in South Africa. Currently, the occurrence of PLRV infection in potatoes of South Africa has reached epidemic proportions. A previous phylogenetic investigation undertaken in our laboratory of South African PLRV isolates, using coat protein (CP) gene sequences, found large variation between native South African PLRV isolates and most other isolates from elsewhere in the world; with their nearest relatives being single isolates from Australia and North America. In this study the incidence of PVX, PVM, PVA, PVS, PMTV, TSWV and PSTVd was investigated. A large number of potato plant and tuber samples was collected and infected samples were identified with reverse transcriptase polymerase chain reaction (RT-PCR) amplification of the CP gene or the whole genome in the case of PSTVd. The amplified nucleic acid segments were sequenced, aligned with international reference sequences and analysed phylogenetically to determine their relative relationships with these reference sequences. The CP genes of PLRV isolates were sequenced and phylogenetically investigated to determine how these new isolates compared relative to the previous findings from our laboratory. In addition, the complete genomes of two PLRV isolates were sequenced and phylogenetically investigated as a preliminary study to investigate the apparent increase of pathogenicity of certain variants of South African PLRV. Results obtained showed that only PVX and PVS were present in the samples collected and the incidences of these viruses were very low (2.0 and 1.1% respectively). The phylogenetic analyses of the CP genes, indicated that the PVX and PVS variants isolated in this study, were part of the dominant types of variants found worldwide. From the analyses of the PLRV CP and whole genome sequences, it was determined that many of the PLRV variants found in South Africa, are genetically distinctly different from those around the world. This warrants further investigation into the increased pathogenicity experienced with South African PLRV. / AFRIKAANSE OPSOMMING: Infeksie van aartappels deur virale patogene veroorsaak verlaagde opbrengs en gevolglike ekonomiese verlies. In Suid-Afrika is Aartappelvirus Y (PVY) en Aartappelrolblad virus (PLRV) die twee mees vernietigende virusse wat aartappels infekteer. Verskeie ander virale patogene, insluitend Aartappelvirus X (PVX), Aartappelvirus M (PVM), Aartappelvirus A (PVA), Aartappelvirus S (PVS), Aartappel "moptop" virus (PMTV), Kromnekvirus (TSWV) en Aartappel "spindle tuber" viroïed (PSTVd) kom ook wêreldwyd in aartappels voor. Alhoewel hierdie virusse aartappels wêreldwyd besmet, is daar geen gepubliseerde inligting met betrekking tot die voorkoms van hierdie virusse of die viroïed in Suid-Afrika nie. Tans het die voorkoms van PLRV infeksie in aartappels in Suid-Afrika epidemiese proporsies bereik. In 'n vorige filogenetiese ondersoek van die mantelproteïen (MP) nukleotiedvolgordes van Suid Afrikaanse PLRV isolate in ons laboratorium, is groot variasie tussen hierdie inheemse isolate en die meeste ander isolate van elders in die wêreld bevind. Die Suid Afrikaanse PLRV variante betree 'n unieke intermediêre posisie tussen die internasionale isolate en enkele isolate van Australië en Amerika. In hierdie studie is die voorkoms van PVX, PVM, PVA, PVS, PMTV, TSWV en PSTVd ondersoek. Groot aantal aartappelplant en -knol monsters is versamel en infeksie is getoets met tru-transkripsie polimerase kettingreaksie (RT-PCR) amplifisering van die MP geen, of die hele genoom in die geval van PSTVd. Die nukleïensuurvolgordes is bepaal en vergelyk met internasionale verwysingsvolgordes. Die relatiewe verhoudings tussen die bepaalde volgordes en die verwysingsvolgordes is geanaliseer met filogeneties ontledings. Die MP gene van PLRV isolate se volgordes is bepaal en filogeneties ontleed om hierdie nuwe isolate te vergelyk relatief tot vorige bevindinge in ons laboratorium. Die volledige genome van twee PLRV isolate se volgordes is bepaal en filogeneties ontleed as 'n voorlopige studie om die oënskynlike toename in patogenisiteit van Suid-Afrikaanse PLRV te ondersoek. Resultate het getoon dat slegs PVX en PVS teenwoordig was in die monsters wat versamel is en dat die voorkoms van hierdie virusse baie laag was (2.0% en 1.1% onderskeidelik). Die filogenetiese ontleding van die MP gene het aangedui dat die Suid Afrikaanse variante van PVX en PVS, geisoleer in hierdie studie, van die dominante tipes is wat mees gereeld internationaal voorkom. Uit die ontleding van die PLRV MP en heelgenoom volgordes, is vasgestel dat baie van die PLRV variante wat in Suid-Afrika aangetref word, geneties meer verskillend is as die van regoor die wêreld. Dus, regverdig dit, verdere ondersoek van die verhoogde patogenisiteit van Suid Afrikaanse PLRV variante.

No description available.

2008 m. Lietuvos žemės ūkio universiteto Bandymų stotyje atlikus organinių azoto trąšų Provita įtakos ekologiškai auginamoms bulvėms tyrimus, nustatyta, kad tręšimas organinėmis azoto trąšomis Provita, bei organinių azoto trąšų Provita deriniais su Patenkali ir fosforitmilčiais esminiai padidino bulvių suminį ir prekinį derlingumą bei derliaus prekingumą. Patręšus Provita, Patenkali ir fosforitmilčiais bei Provita ir Patenkali esminiai padidėjo suminis ir prekinis bulvių derlingumas, lyginant su tręšimu Provita bei Provita ir fosforitmilčių trąšų deriniu. Bulves patręšus Provita, Provita ir Patenkali bei Provita, Patenkali ir fosforitmilčiais esminiai sumažėjo bulvėse krakmolo, lyginant su netręštomis bulvėmis. Patręšus bulves organinėmis azoto trąšomis Provita esminiai sumažėjo sausųjų medžiagų bulvių gumbuose, lyginant su netręštomis bulvėmis bei tręšimu Provita, kalio ir fosforo trąšų deriniais. Tręšiant organinėmis azoto trąšomis Provita gautas neigiamas azoto balansas. Tręšimas N60 organinių azoto trąšų norma, neužtikrino teigiamo azoto balanso dirvožemyje. / Research on the effect of organic nitric fertilizers Provita to organically cultivated potatoes performed in 2008 at the experimental station of Lithuanian University of Agriculture highlighted, that fertilization of potatoes with organic nitric fertilizers Provita, as well as combinations of organic nitric fertilizers Provita with Patenkali and phosphorite powder, significantly increased total and marketable harvest of potatoes, as well as merchantability of harvest. In case of fertilization with Provita, Patenkali and phosphorite powder, as well as Provita and Patenkali, total and marketable harvest of potatoes was significantly increased, compared with fertilization using Provita and the combination of Provita and phosphorite powder. After fertilization of potatoes with Provita, Provita and Patenkali as well as Provita, Patenkali and phosphorite powder, the concentration of starch in potatoes was significanlty lower, than in these never fertilized. After fertilization of potatoes with organic nitric fertilizers Provita, the concentration of dry matterial in potatoes was significantly decreased, compared to these never fertilized, or fertilized with Provita, combinations of kalium and phosphoric fertilizers. Fertilization of potatoes had no significant effect to the concentration of soluble dry matterial in potatoes. Fertilization with organic nitric fertilizers Provita resulted in negative nitric balance. Fertilization with standard volume of organic nitric fertilizers N... [to full text]

Laikant bulves storame 5 – 6 m storio sluoksnyje, aruode sunku likviduoti susidariusius gedimo židinius. Židinio pašalinimui būtina suintensyvinti ventiliavimą, kad mumifikuoti gedimo židinyje esančius sugedusius gumbus. Tyrimų tikslas - ištirti ventiliuojamo oro paskirstymo dėsningumus bulvių sandėlio sampile ir eksperimentiniame oro paskirstymo stende. Nustatyti oro paskirstymą ventiliuojamame sampile, keičiant skirstomųjų ortakių skaičių, bei ištirti ventiliavimo suintensyvinimo galimybes susidarančias gedimo zonoje. Nustatyta, kad sumažinus atidarytų skirstomųjų ortakių skaičių, galima padvigubinti ventiliavimo intensyvumą likusiuose atidarytuose ortakiuose. Esant atidarytam vienam skirstomajam ortakiui, tiekiamas 8,34 /s oro srautas. Atidarius visus aštuonis ortakius, į kiekvieną ortakį tiekiama tik 3,9 /s oro. Šalia židinio esantys produkcijos sluoksniai bus ventiliuojami žymiai mažesniu ventiliavimo intensyvumu, kas sumažina produkcijos perventiliavimo galimybes likviduojant gedimo židinį sandėlio aruode. / Holding potatoes in a thick 5-6 m layer in the bin it is difficult to eliminate originated hot spots. To remove the source it is necessary to intensify ventilation in order to mummify defective tubers in corruption source. The aim of the research is to investigate the patterns of ventilated air distribution in potato store and distribution of air in an experimental bench. To determine air distribution in ventilated store by changing the number of distribution ducts, and to explore opportunities to intensify ventilation arising in corruption area. It was found that reducing the number of opened distribution ducts the intensity of the ventilation in the remaining opened ducts can be doubled. At the invitation of one ducts supplied 8.34 m3/s air flow. After opening all eight ducts, each duct to be supplied only 3.9 m3/s in air. The layers next to the source will be ventilated with much smaller intensity, which decreases possibility to over ventilate production while eliminating corruption source in the store bin.