Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2001. / Härtill 5 uppsatser.

No description available.

La producción de alcohol se encuentra relacionada directamente con la producción de Biocombustibles, debido al desplazamiento de importantes volúmenes de alcohol para su conversión en etanol o alcohol anhídrido; usado como complemento o sustituto de la gasolina. Esta situación ha generado que la caña de azúcar, principal materia prima para la elaboración de alcohol se convierta en un “bien escaso” y sea necesario buscar otras potenciales fuentes para su producción. En el Perú, existe también el potencial para producir el mencionado producto, usando los tubérculos como base, especialmente la papa; a través de la conversión de almidones en azúcares y su posterior fermentación y destilación en alcohol etílico. La presente investigación tiene por finalidad demostrar la viabilidad de la instalación de una planta de producción de alcohol de papa en la provincia de Chota, departamento de Cajamarca, con la intención de atender al mercado interno, con un producto de alta calidad, orientado al uso industrial, farmacéutico y cosmético. La metodología desarrollada comprende la determinación de viabilidad de Mercado, Organizacional, Técnico Operativa, Económica financiera y ambiental. Finalmente se concluye que es viable la instalación de una planta de producción de alcohol en la provincia de Chota. / Tesis

215 h. / La producción de alcohol se encuentra relacionada directamente con la producción de Biocombustibles, debido al desplazamiento de importantes volúmenes de alcohol para su conversión en etanol o alcohol anhídrido; usado como complemento o sustituto de la gasolina. Esta situación ha generado que la caña de azúcar, principal materia prima para la elaboración de alcohol se convierta en un “bien escaso” y sea necesario buscar otras potenciales fuentes para su producción. En el Perú, existe también el potencial para producir el mencionado producto, usando los tubérculos como base, especialmente la papa; a través de la conversión de almidones en azúcares y su posterior fermentación y destilación en alcohol etílico. La presente investigación tiene por finalidad demostrar la viabilidad de la instalación de una planta de producción de alcohol de papa en la provincia de Chota, departamento de Cajamarca, con la intención de atender al mercado interno, con un producto de alta calidad, orientado al uso industrial, farmacéutico y cosmético. La metodología desarrollada comprende la determinación de viabilidad de Mercado, Organizacional, Técnico Operativa, Económica financiera y ambiental. Finalmente se concluye que es viable la instalación de una planta de producción de alcohol en la provincia de Chota.

Microtubers were obtained from potato plants (Solanum tuberosum L.) cultured in vitro, they were used in following experiments. The impact of growth regulators (FLD, AgNO3, BA, ABA) was monitored in length of dormancy. The content of ABA in the budding tubers and the content of endogenous CK (BA, IP, DHZ, DHZR, Z) was determined during the dormancy as well. Production of ACC, ethylene, O2, CO2 and ethane was determined by gas chromatography. Variants containing FLD, AgNO3 and BA had a significant impact in the shortening of dormancy and stimulation the growth of buds microtubers. When they were used the occurrence of budding tubers was increased by 30-40 % over the control. Variant of ABA inhibited the growth of buds. ABA content correlated with the process of dormancy and the occurrence of budding tubers. The highest content of ABA was in variant with freshly collected dormant tubers. Concentration of various CK was dependent on the type of CK and monitored variant. Generally, It was slightly increased with occurrence of budding tubers.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2016-01-07T08:08:29Z No. of bitstreams: 1 texto completo.pdf: 385459 bytes, checksum: f1b68d6dade6f1f37952de2eeedf571a (MD5) / Made available in DSpace on 2016-01-07T08:08:29Z (GMT). No. of bitstreams: 1 texto completo.pdf: 385459 bytes, checksum: f1b68d6dade6f1f37952de2eeedf571a (MD5) Previous issue date: 2015-07-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O selênio (Se) é elemento traço essencial às funções do corpo humano, como controle do metabolismo de hormônios e de doenças cardiovasculares, prevenção da doença de Kashin-Beck, além de ter ação anticarcinogênica. Os teores de selênio (Se) nas plantas estão relacionados com a disponibilidade deste elemento no solo e a capacidade de absorção e acúmulo pelas plantas. Com intuito de produzir alimentos nutricionalmente mais completos e saudáveis para consumo humano e animal, uma estratégia utilizada é a biofortificação. Assim, objetivou-se avaliar doses e formas de aplicação de Se para fortificar tubérculos de batata. Os experimentos foram conduzidos em casa de vegetação, em vasos de 8 dm-3 de solo e selenato de sódio como fonte de Se. O delineamento foi o inteiramente aleatorizado com cinco repetições e os tratamentos consistiram de cinco doses via solo (0; 0,12; 0,25; 0,50 e 1,0 mg dm -3de Se) e cinco concentrações via foliar (0; 0,10; 0,21; 0,31 e 0,42 % de Se). Foram avaliados sintomas de fitotoxicidade, alterações fisiológicas ou morfológicas nas plantas, produtividade, variáveis fotossintéticas, atividade antioxidante total nos tubérculos e teores de Se no solo, parte aérea e nos tubérculos de batata. A aplicação de Se via solo não influenciou as variáveis fotossintéticas, o crescimento das plantas e a produção de tubérculos. Por outro lado, a aplicação foliar causou fitotoxidade nas folhas e redução na produção e na matéria seca de tubérculos. A atividade antioxidante total nos tubérculos não apresentou diferença entre os tratamentos. A aplicação de Se, independente da forma de aplicação e dose testada, não apresentou efeito significativo quanto aos teores de P, Mg, Zn, Cu, Fe e Ca nos tubérculos. Entretanto, observaram-se diferenças significativas quanto ao teor de Se nos tubérculos, em ambas as formas de aplicação e nas menores doses testadas. Os tubérculos de batata são capazes de acumular Se de maneira eficiente e a parte aérea das plantas transloca este elemento para os tubérculos, mesmo sob níveis severos de fitotoxidade. Palavras chave: Solanum tuberosum, translocação, nutrição humana. / Selenium (Se) is an essential trace element the human body functions such as hormone metabolism and control of cardiovascular diseases, prevention of Kashin-Beck disease, and have anticarcinogenic action.The levels of Se in the plant are related to the availability of this element in the soil and the ability to uptake and accumulation, of plants. Aiming to produce more nutritionally complete and healthy foods for human consumption and animal, a strategy used is biofortification. This experiment aimed to evaluate doses and Se application forms able to fortify potato tubers. The experiments were conducted in greenhouse, in pots of 8 dm-3 of soil and sodium selenate as a source of Se. The design was completely randomized with five replications and the treatments consisted of five doses in the soil (0; 0.12; 0.25; 0.50 and 1.0 mg dm-3 Se) and five foliar concentrations (0; 0.10; 0.21; 0.31 and 0.42 % of Se). Were evaluated phytotoxicity symptoms, physiological or morphological changes in plants, productivity, photosynthetic variables, total antioxidant activity in the tubers and Se levels in the soil, shoot and potato tubers. The use of Se in the soil did not affect the photosynthetic variables, the growth of plants and tuber yield. Moreover, foliar application caused phytotoxicity on leaves and reduction in dry matter production and tubers. The total antioxidant activity in the tubers showed no difference between treatments. Applying Se, regardless of the form of application and dose tested, no significant effect as the P, Mg, Zn, Cu, Fe and Ca contents in tubers was observed. However, there were significant differences in the Se content of tubers in both application forms and in smaller doses tested. The potato tubers are able to accumulate Se efficiently and the shoot translocates this element to the tubers, even with severe levels of phytotoxicity. Keywords: Solanum tuberosum, translocation, human nutrition.

No description available.

Fusarium is a soilborne fungus which can live in soil for long periods of time. It is known to cause wilt, root rot and crown rot diseases in a diverse group of crop plants. Of all the diseases caused by Fusarium the most important are the vascular wilts. Pathogens that cause wilting usually enter their host plant through young roots and then grow into and up the water-conducting vessels of the root and stem. The vessels become blocked and water supply to the leaves is limited. This results in the potato plant being weak resulting in yellowing of leaves, browning of stems and production of smaller tubers. Fusarium is diverse and widely distributed and can be isolated from agricultural soils and plant material. The study was done to determine the occurrence of this pathogen in the South African potato industry. Samples of plant material showing wilt symptoms were collected from nine potato production regions. Fungal isolations were made from tubers using a Fusarium selective medium, i.e Peptone PCNB Agar. The isolates were examined morphologically and those resembling Fusarium were further identified using molecular techniques. DNA sequence analysis of the translation elongation factor 1-α gene was done on the isolates. DNA-based techniques have increasingly become the tool of choice for understanding the genetic diversity and phylogeny of Fusarium species. The pathogenicity of the isolates from all the regions was also investigated on potato cultivar Caren. The DNA results confirmed Fusarium as the pathogen causing Fusarium wilt on potatoes. Two species of Fusarium were identified; namely F. oxysporum and F. solani. F. oxysporum was more prevalent and occurred in all regions compared to F. solani. F. oxysporum is best known for the plant pathogenic strain, which cause wilt, root rot and crown rot diseases on a wide variety of crops, often limiting crop production. It is also known to be phylogenetically diverse. In the pathogenicity test, the isolates were found to be virulent and one was highly virulent therefore confirming their ability to cause wilting of potatoes. The effect of silicon on Fusarium wilt of potatoes was investigated in this study to assess its effectiveness in the control of Fusarium wilt. An in vitro study using potassium silicate was done to determine if silicon can inhibit the growth of Fusarium at different concentrations. The results showed that at low concentrations of potassium silicate the growth of Fusarium was not inhibited, while at a high concentration, there was inhibition. Greenhouse pot trials were conducted to determine the effect of silicon soil amendments on Fusarium wilt of potatoes, tuber yield and the production of phenolics in the cell wall of potato peels. The levels of chlorogenic, caffeic and ferulic acids were also investigated. The following treatments were used: control, silicon ash (~99% Si), slag (30% Si), fly ash (50% Si) and lime (calcium carbonate) as a pH control. Treatments were divided into those inoculated with Fusarium and those without Fusarium. Results showed that for silicon treatments not inoculated with Fusarium, slag had the highest tuber yield, followed by lime, fly ash and silicon ash when compared to the control. Silicon treatments inoculated with Fusarium did not improve the yield as the control had the highest yield and the occurrence Fusarium wilt was not reduced in silicon treatments. In this regard silicon did not have an effect on Fusarium wilt because symptoms were visible in the silicon amended treatments. The results for phenolic acid content showed that ferulic acid levels were too low for analysis; for chlorogenic acid, concentrations were generally lower in the silicon treatments than in the treatments without silicon; and caffeic acid levels were higher in silicon treatments than treatments without silicon, as a result of increased production of as defence mechanism against invading pathogens. However, this is the first study on the effect of silicon on Fusarium wilt of potatoes and its influence on the production of phenolics. Further research is required to understand the role of silicon in potato pathosystems. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Microbiology and Plant Pathology / unrestricted

Pectobacterium carotovorum (Pbc), Dickeya spp., Pectobacterium atrosepticum (Pba), and a new, atypical strain, Pectobacterium carotovorum subsp. brasiliensis (Pbcb) can cause potato blackleg, soft rot and aerial stem rot. To determine the impact and extent of these pathogens on the South African potato industry, samples were collected from 72 potato fields in 10 potato production regions during the 2006/7 production seasons. During these seasons, blackleg outbreaks occurred in commercial production fields causing severe economic losses. Bacteria isolated from diseased material that were Gram-negative, facultative anaerobic with pectolytic ability were identified using a Multiplex PCR targeting the 16S-23S region. Isolates were subjected to partial sequencing of the 16S-23S rDNA and a subsequent PCR-RFLP of the 16S-23S rDNA region. Comparison of RFLP patterns of isolates to reference cultures confirmed the identity of the South African blackleg strains as Pbcb. This is the first report of Pbcb in South Africa. A total of 128 isolates were obtained from 10 production regions. Of these 77% were shown to be Pbcb, 17% Pbc and 6% unkown. Dickeya spp. and Pba were not detected in South Africa. From imported tubers 14 isolates were obtained, 13 of which were identified as Pbcb and one isolate as Pbc. Thus Pbcb was shown to be the most important causal agent of blackleg and soft rot in South Africa and poses a threat to the South African potato industry. Through a questionnaire survey the farmers` knowledge of soft rot / blackleg disease complex and the need for research on these potato diseases in South Africa was determined. A total of 41 questionnaires were collected from potato growers and analysed. Estimates of economic losses experienced by growers due to soft rot / blackleg disease complex, ranged from 1 to 70%. It appears that in South Africa disease symptoms are mainly prevalent at temperate (10 – 20°C) to warm climates with prolonged wet or humid conditions. To reduce disease incidence, low generation seed tubers need to be planted and good crop rotation systems need to be followed. Blackleg is mainly a seed-borne disease and is therefore difficult to control. This prompted the search for a possible management strategy to increase plant / tuber resistance to blackleg and soft rot and to minimise losses. The study also focussed on the effect of a calcium silicate slag soil amendment on phenolic formation in cell walls of potato peels, and subsequent tuber resistance to Pectobacterium carotovorum subsp. brasiliensis (Pbcb) . Pot trials were conducted with the following treatments: Control with and without the pathogen; slag (30% Si) with and without the pathogen; lime treatment (CaCO3) as pH control with and without the pathogen. Results from pot trials show that phenol production in potato stems and tubers increased in both lime and slag treatments, compared to the controls. This suggests that soil pH may play a role in phenol production. This could, however be due to increased silicon absorption by plants at higher pH values. Results also indicate that the best Si source to use is Calmasil, since Si and Ca combined have a synergistic effect in enhancing tuber resistance. This is, however, the first study on the effect of Si on defence responses of potatoes and further research is required to elucidate the modes-of-action of Si in the potato plant. This study has enhanced the understanding of the etiology of soft rot / blackleg diseases in South Africa and opened up new possibilities for the use of Si in commercial production to improve plant health status. However the need for future research on this disease complex has been highlighted in this thesis. / Dissertation (MSc)--University of Pretoria, 2009. / Microbiology and Plant Pathology / unrestricted

O Tomato chlorosis virus (ToCV) é uma espécie do gênero Crinivirus que causa danos, principalmente na cultura do tomateiro (Solanum lycopersicum). Foi primeiramente isolado e descrito em 1998, nos Estados Unidos, e em seguida foi reportado em doze países. No Brasil, foi constatado primeiramente no Estado de São Paulo, na região de Sumaré, em 2008, e posteriormente nos Estados da Bahia, Espírito Santo, Goiás, Minas Gerais e Rio de Janeiro. Há evidência da sua presença também nos Estados do Paraná e Santa Catarina. O ToCV pode infectar outras solanáceas além do tomateiro e, recentemente, foi observado infectando plantas de batata (Solanum tuberosum) no Brasil. Esse crinivirus é transmitido no Brasil principalmente pelo aleirodídeo (mosca branca) Bemisia tabaci MEAM1. Considerando o patossistema batateira/ToCV, não há estudos sobre a ocorrência, sintomatologia em diferentes variedades e danos provocados por esse crinivirus. Também não há antissoro policlonal para o isolado brasileiro do ToCV para uso na diagnose da doença em solanáceas. Esse trabalho teve por objetivos: purificar o ToCV e produzir antissoro policlonal; avaliar a reação de genótipos de batateira à infecção com o ToCV; avaliar o dano provocado por esse vírus em duas variedades de batateira. A purificação do vírus a partir de folhas de tomateiro e a produção de antissoro policlonal em coelho foram satisfatórias. No entanto, o antissoro não foi eficiente em ELISA, mas sim em dot-blot e somente na diluição de 1:20. Foi avaliada a reação de 21 genótipos de batateira à infecção com o ToCV, por meio da inoculação com B. tabaci MEAM1, com chance de escolha do vetor. Nenhum genótipo exibiu resistência à infecção; enquanto a variedade Camila foi assintomática e não apresentou alteração na fotossíntese. Plantas de batateira das variedades Ágata e Asterix sadias foram inoculadas com o ToCV, por meio da B. tabaci MEAM1 e ao final foram avaliadas a massa fresca da parte aérea, peso e número dos tubérculos colhidos. Em dois experimentos independentes, as reduções médias no peso fresco da parte aérea foram de 60,1% para Ágata e 46% para Asterix. Porém, as reduções nas produções dessas variedades, no primeiro experimento foram de 99,5% e 98,1%, respectivamente; enquanto no segundo os valores foram de 82,3% e 56,2%, respectivamente. / Tomato chlorosis virus (ToCV) is a species of the genus Crinivirus, which is causing considerable losses mainly on tomato crop (Solanum lycopersicum). It was first isolated and described on 1998 in the United States and subsequently reported in twelve countries. In Brazil, it was first reported in São Paulo State, in Sumaré region in 2008, and after that on the states of Bahia, Espírito Santo, Goiás, Minas Gerais and Rio de Janeiro. There is evidence of the presence of ToCV on the states of Paraná and Santa Catarina. ToCV can also infect other solanaceae and more recently, it was reported infecting potato plants (Solanum tuberosum) in Brazil. This crinivirus is transmitted by Bemisia tabaci MEAM1. Considering the patosystem potato/ToCV, there are no studies on the occurrence, symptomatology in different varieties, and damages caused by this crinivirus. In addition, there is no polyclonal antiserum for the Brazilian isolate of ToCV for use in diagnosis. The objectives of the present work were: to purify the virus and produce a polyclonal antiserum; to evaluate the reaction of potato genotypes to ToCV infection; to evaluate the yield loss caused by this crinivirus on two potato cultivars. The virus purification from tomato leaves and the production of polyclonal antiserum in rabbit were satisfactorily accomplished. However, the antiserum was not efficient on ELISA test, but in dot-blot, only when diluted 1:20. The reaction of 21 potato genotypes to infection with ToCV was evaluated by inoculation with B. tabaci MEAM1, with chance of choice for the vector. All genotypes were infected with ToCV and Camila was the only one asymptomatic. Plants of cultivars Ágata and Asterix were inoculated with ToCV, by means of viruliferous vector, and at the end were evaluated for the fresh mass of the aerial part, weight and number of harvested tubers. In two independent experiments, average reductions in aerial fresh weight were 60.1% for Ágata and 46% for Asterix. However, reductions in yield of these varieties in the first experiment were 99.5% and 98.1%, respectively; while in the second the values were 82.3% and 56.2%, respectively.