Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-06T13:12:00Z No. of bitstreams: 1 melviscelestevilanculoscossa.pdf: 1078778 bytes, checksum: 97bdef4f96b42adf5a7860d727162f8f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:59:51Z (GMT) No. of bitstreams: 1 melviscelestevilanculoscossa.pdf: 1078778 bytes, checksum: 97bdef4f96b42adf5a7860d727162f8f (MD5) / Made available in DSpace on 2016-04-24T03:59:51Z (GMT). No. of bitstreams: 1 melviscelestevilanculoscossa.pdf: 1078778 bytes, checksum: 97bdef4f96b42adf5a7860d727162f8f (MD5) Previous issue date: 2013-02-27 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / A batata uma essencial “comida para todos”, é hoje uma das mais importantes culturas alimentares e constitui a quarta cultura mais importante do mundo, sendo também fonte de segurança alimentar. Todavia, muitas doenças causadas por vírus, bactérias e fungos afetam a cultura desta planta, resultando em perdas e diminuição da qualidade e segurança dos produtos agrícolas. O controle de doenças nas plantas baseia-se principalmente de pesticidas químicos que estão atualmente sujeitos a fortes restrições e requisitos regulamentares. Nesse sentido, vários peptídeos antimicrobianos têm sido a base para a concepção de novos análogos sintéticos e têm sido expressos em plantas transgênicas para conferir proteção a doenças. O desenvolvimento de plantas transgênicas, contendo um gene que sintetiza um peptídeo antibacteriano, tem sido uma das formas estudadas para se controlar doenças bacterianas. No presente estudo, plantas de batata (Solanum tuberosum), cultivar Asterix, foram transformadas com genes codificadores do peptídeo Pg-AMP1 de Psidium guajava, com objetivo de promover resistência a bactérias que afetam a cultura da batata, nomeadamente Pectobacterium atrosepticum e Pectobacterium carotovorum. Experimentos de transformação genética mediada por Agrobacterium permitiram a obtenção de 13 linhagens transgênicas de Solanum tuberosum Pg-AMP1, representando eventos independentes de transformação. Paralelamente aos experimentos de transformação genética, foram realizados bioensaios in vitro com o peptídeo recombinante purificado Pg-AMP1 contra as cepas bacterianas P. atrosepticum e P. carotovorum e bioensaio in vivo em folhas de plantas de tabaco (Nicotiana tabacum) transformada com o peptídeo com as mesmas cepas bacterianas. No que se refere à resistência das folhas contra o ataque das bactérias P. atrosepticum e P. carotovorum, as linhagens transformadas de tabaco Pg-AMP1 apresentaram sintomas de necrose menos severos comparativamente as não transgênicas. Do mesmo modo o peptídeo Pg-AMP1 apresentou atividade bactericida contra as cepas bacterianas P. atrosepticum e P. carotovorum. Assim sendo, estes resultados sugerem a viabilidade do peptídeo Pg-AMP1 na utilização de transformações genéticas de Solanum tuberosum visando resistência a bactérias patogênicas que afetam a cultura. / Potato, known as essential "food for all", is one of the most important food crops in nowadays. It is the fourth most important crop in the world and is also a source for food security. However, many diseases caused by viruses, bacteria and fungi affect plant cultivation, resulting in losses and decrease the quality and safety of agricultural products. The control of plant diseases is mainly based on chemical pesticides that are currently subject to severe restrictions and regulatory requirements. Accordingly, various antimicrobial peptides have being the basis for new synthetic analogs designing and have been expressed in transgenic plants to confer disease protection. The development of transgenic plants containing a gene that synthesizes an antibacterial peptide, has been has been used to bacterial diseases control. In this study, potato plants (Solanum tuberosum) Asterix, were transformed with genes encoding the peptide Pg-AMP1 from Psidium guajava aiming to produce resistant plants to Pectobacterium atrosepticum and Pectobacterium carotovorum. Experiments of genetic transformation by Agrobacterium - mediated allowed 13 different events of transgenic Solanum tuberosum Pg-AMP1, representing different transformation events. In parallel to genetic transformation experiments in vitro bioassay with recombinant peptide purified Pg-AMP1 was performed. Bacterial strains P. atrosepticum and P. carotovorum were evaluated and in vivo in Tobacco (Nicotiana tabacum) leaves from transformed plants containing the peptide. In resistance assay against P. atrosepticum and P. carotovorum in tobacco plants showed less severe symptoms compared to non-transgenic. Likewise the Pg- AMP1 peptide showed bactericidal activity against bacterial strains P. atrosepticum and P. carotovorum. Thus, these results suggest the feasibility of the peptide Pg- AMP1 the use of genetic transformation of Solanum tuberosum for resistance to pathogenic bacteria that affect the crop.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2016-09-13T17:57:54Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) final_dissertacao_carini.pdf: 1672234 bytes, checksum: 9d8c7310c47d04b68001dacf5bc044c4 (MD5) / Made available in DSpace on 2016-09-13T17:57:54Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) final_dissertacao_carini.pdf: 1672234 bytes, checksum: 9d8c7310c47d04b68001dacf5bc044c4 (MD5) Previous issue date: 2016-02-13 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / O cultivo do tomateiro em sistemas de cultivo sem solo com recirculação da solução nutritiva drenada pode ser uma alternativa viável para a obtenção de alto rendimento e qualidade de frutos, além de otimizar os recursos produtivos, com reduzido impacto ambiental. Neste sentido, existe a necessidade de se estudar o sistema fechado de cultivo em substrato e o cultivo hidropônico. Paralelamente, é necessária a escolha de cultivares que respondam positivamente às tecnologias propostas. Dentro deste contexto, dois experimentos foram conduzidos em estufa plástica, localizada no Campus da Universidade Federal de Pelotas, no município de Capão do Leão/RS no ano agrícola 2014/15. O experimento 1 teve como objetivo avaliar os efeitos da adição de composto orgânico (CO) à casca de arroz in natura (CAIN) sobre as características físicas e químicas do substrato [através da comparação entre a CAIN (100%) e a mistura de CAIN (80%) + CO (20%)] e o crescimento e o comportamento produtivo de quatro cultivares híbridas de tomateiro salada [Ivety, Sophia-F3, Sheila Victoria e Lumi (Sakata® Seed)]. O experimento 2 objetivou determinar a soma térmica e quantificar o consumo hídrico, determinar a eficiência no uso da água (EUA), bem como os componentes do rendimento e a qualidade de dois híbridos de plantas de minitomate [Wanda e Dolcetto (Isla®)] em cultivo hidropônico NFT. Em relação aos resultados obtidos no experimento 1, para todas as variáveis analisadas, não houve interação significativa entre substrato e cultivar. A adição de CO melhorou as características físicas e químicas do substrato, porém, não afetou as principais características de crescimento e produtivas da cultura. As quatro cultivares apresentaram crescimento e produção de frutos semelhantes, porém Sheila Victoria se destacou pela maior concentração de sólidos solúveis totais. As produções obtidas são consideradas elevadas, variando entre 6,3kg.planta-1, para as cultivares Sophya e Sheila Victoria, passando por 6,5kg.planta-1, para a cultivar Lumi, até 7,6kg.planta-1 obtidos com a cultivar Ivety. Os resultados indicam ser 9 desnecessária a adição de CO à CAIN e que as quatro cultivares se adaptam de forma semelhante ao sistema proposto. Em relação aos resultados obtidos no experimento 2, observou-se que a cultivar Wanda é mais precoce do que a cultivar Dolcetto. O período em que ocorre maior acúmulo de graus dia, para ambas as cultivares, é na fase fenológica IV (colheita). A cultivar Dolcetto apresenta menor consumo hídrico total. A demanda máxima diária de água é de 1,53 e 2,12 litros planta-1 dia-1, e a demanda total foi de 190,6 e 261,7 litros planta-1, respectivamente para ‘Dolcetto’ e ‘Wanda’. As cultivares apresentam similaridade em relação à eficiência no uso da água. Para a produção de um kg de massa fresca de frutos, foram necessários 50,5 e 48,3 litros de água, respectivamente, para ‘Wanda’ e ‘Dolcetto’. A cultivar Wanda é mais produtiva (15,34 kg m-2, frente a 12,14 kg m-2 obtidos com ‘Dolcetto’) e apresenta frutos de maior tamanho. Entretanto, Dolcetto produz um maior número de frutos, com maior concentração de sólidos solúveis e com descarte inferior. Considerando as características avaliadas, pode-se inferir que a cultivar Dolcetto é mais adequada para o cultivo do plantas de minitomate em sistema hidropônico. / Tomato crop in soilless growing systems with recirculation of drain nutrient solution can be a viable alternative for obtaining high yield and quality of fruit, as well as optimize the productive resources, with low environmental impact. In this sense, to study both closed substrate growing and hydroponic cultivation systems is necessary. At the same time, the choice of varieties to respond positively to the proposed technologies is very important. Within this context, two experiments were carried out in a plastic greenhouse, located at the Campus of the ‘Universidade Federal de Pelotas’, in the municipality of Capão do Leão/RS in the agricultural year 2014/15. The experiment 1 aimed to evaluate the effects of adding organic compost (OC) to the raw rice husk (RRH) on the physical and chemical properties of the substrate [through the comparison between the RRH (100%) and RRH (80%) + OC (20%)] and on plant growth and fruit production responses of four tomato hydrid varieties [Ivety, Sophia, Sheila Victoria and Lumi (Sakata ® Seed)]. The experiment 2 aimed to determine the thermal time, the water consumption and the water use efficiency (WUE), as well as the yield components and fruit quality of two small tomato varieties [Wanda and Dolcetto (Isla ®)] grown in NFT hydroponic system. In relation to the results obtained in experiment 1, for all variables analyzed, there was no significant interaction between substrate and Variety. The addition of OC has improved the physical and chemical proporties of the substrate, however, did not affect the major plant growth and fruit production characteristics or the crop. The four varieties showed similar plant growth and fruit yield, but Sheila Victoria stood out by the highest concentration of total soluble solid contents. The obtained yields are considered high, ranging from 6.3 kg.plant-1 for the varieties Sophya and Sheila Victoria, passing 6.5 kg.plant-1, for variety Lumi, up to 7.0 kg.plant-1 obtained for the variety Ivety. The results indicate be unnecessary addition of OC to RRH and that the four varieties adapted similarly to the proposed system. In relation to the results obtained in experiment 2, the variety Wanda is earlier than the variety Dolcetto. The period of greatest accumulation of degrees day, for both 11 varieties, was in the phenology phase IV (harvest). Variety Dolcetto presented lower total water consumption. Maximum daily water demand was 1.53 and 2.12 liters-1 plant- 1 day-1 and the total water demand was 190.6 and 261.7 liters.plant-1, respectively to 'Dolcetto ' and 'Wanda'. The varieties presented similarity with respect to WUE. For the production of one kg of fruit fresh matter, it was necessary 50.5 and 48.3 liters of water, respectively, for 'Wanda' and 'Dolcetto'. Variety Wanda presented higher yield (15.34 kg m-2, in front of 12.14 kg m-2 obtained with 'Dolcetto') and larger fruit. However, Dolcetto produced more fruits, with higher soluble solid contents and presented lower fruit loss. Considering the characteristics evaluated, one can infer that variety Dolcetto is best suited for the growing of the small tomato in hydroponic system.

Made available in DSpace on 2014-06-12T23:14:48Z (GMT). No. of bitstreams: 2 arquivo8684_1.pdf: 514323 bytes, checksum: d4cfce8aa464e24d243be276092dc11f (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O objetivo geral desse trabalho foi estudar a relação da adubação orgânica e inorgânica de batatinha em solos arenosos, com a produtividade, nutrição da planta e dinâmica da matéria orgânica e nutriente no solo, em áreas cultivadas com batatinha. O estudo foi dividido em três etapas, cada uma com seus objetivos e metodologias específicas. Etapa 1: As relações entre os teores de nutrientes em solos com adubação orgânica e inorgânica e os teores de nutrientes e produtividade de batatinha foram determinadas, assim como, as relações entre aportes e a lixiviação de N e bases trocáveis. Foram coletadas amostras de solo das camadas de 0 20, 20 40 e 40 60 cm em 18 áreas de produção com adições anuais de esterco variando entre 2 e 40 anos e, como controle, quatro áreas sob pastagem não adubadas. Amostras de solo e planta foram analisadas quanto aos teores de N, P, K, Ca e Mg. A produtividade de batatas grandes teve relação positiva com a entrada de N e produtividade total com N total no solo. Somente o Ca no solo correlacionou-se com os teores na planta, mais não com a produtividade. As bases trocáveis tiveram aumento nas três camadas de acordo com o aumento do esterco aplicado, enquanto o N total só teve aumento nas de 0-20 e 20-40 cm. Etapa 2: O objetivo foi determinar a eficiência do sulfato de amônio (15N) mais esterco na adubação da batatinha e do efeito residual no milheto (Pennisetum glaucum) cultivado em seqüência. Em experimento de campo em Neossolo regolítico foi comparada a combinação de 16 t ha-1 esterco + 80 kg ha-1 de N, utilizada mais freqüentemente na região, com doses de 11 t ha-1 de esterco combinadas com 0, 40 e 80 kg ha-1 de N em doses únicas ou parceladas. A fonte de sulfato de amônio utilizado estava enriquecida em 15N (2,5 % de abundância). Em todos os tratamentos avaliou-se a produção de matéria seca nos tubérculos e na parte aérea do milheto alem da composição isotópica do N nesses materiais. A adubação com dose tradicional é excessiva neste solo, uma vez que a redução para 11 t ha-1 esterco e 40 kg ha-1 de N mineral não resultou em queda de produtividade das culturas; no entanto, houve queda no caso de adubação única com esterco. Etapa 3: A mineralização do esterco foi estimada por três métodos: emissão em de C-CO2 em campo, incubação de solo em laboratório e perda de matéria seca em bolsas de rede plástica. O C-CO2 emitido na superfície do solo foi capturado com solução de NaOH, utilizando câmaras acondicionadas na superfície do solo, em parcelas sem e com (11 t ha-1) aplicação de esterco. Em laboratório foi feita a incubação de solo com adição de esterco (11 t ha-1), combinado ou não com sulfato de amônio (60 kg N ha-1), em recipientes de 2000 ml hermeticamente fechados contendo NaOH para captura do CO2, durante 180 dias. As bolsas de decomposição com adição de esterco (11 t ha-1) com e sem sulfato de amônio (60 kg N ha-1), enterradas a 15 cm de profundidade, foram acompanhadas durante 110 dias. A decomposição do esterco, aplicado isoladamente, estimado via emissão de C-CO2 em campo foi inferior a 5%. No ensaio de laboratório a decomposição, estimada pelo acumulado de C-CO2 emitido, foi muito baixa, 5 e 3,5 % para o esterco aplicado isoladamente e com sulfato de amônio, respectivamente, em 180 dias de incubação. A aplicação de esterco combinado com N mineral apresentou menor emissão de C-CO2 comparado com aplicação isolada. As perdas de matéria orgânica do esterco das bolsas plásticas foram de 41 e 51 % nas parcelas sem e com aplicação de N mineral, respectivamente. Acredita-se que a lenta decomposição do esterco foi determinada pela sua alta relação C/N (38) e alto teor de lignina (14 %). A quantidade de esterco habitualmente utilizada pelos produtores é excessiva, o que favorece a translocação de nutrientes para camadas mais profundas, representando prejuízo econômico e possível risco ambiental. Os resultados obtidos nos ensaios de decomposição e de produção de batata indicam que o esterco não é uma fonte imediata de N e sua aplicação deve ser acompanhada de fontes mais ricas nesse nutriente e de liberação mais rápida. O efeito residual do adubo aplicado foi expressivo para a cultura do milheto cultivado em sucessão, pois o mesmo recuperou grande parte do N mineral adicionado à batatinha e mostrou ser uma alternativa como forrageira em condições de semi-árido

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-01-30T17:45:00Z No. of bitstreams: 1 texto completo.pdf: 382121 bytes, checksum: 19aebf930d73168cc2840a57f9eb672c (MD5) / Made available in DSpace on 2017-01-30T17:45:00Z (GMT). No. of bitstreams: 1 texto completo.pdf: 382121 bytes, checksum: 19aebf930d73168cc2840a57f9eb672c (MD5) Previous issue date: 2016-08-16 / O tomateiro é reconhecido como planta modelo para o estudo do desenvolvimento do fruto de outras espécies que possuem anteras com deiscência poricida, sendo esta uma característica que dificulta o processo de polinização. A polinização mecânica é uma prática que facilita a liberação do pólen, melhorando a produção e qualidade dos frutos. Porém, reduzidas informações acerca da eficiência deste tipo de polinização na produção de frutos restringem seu uso. Nesse sentido, o objetivo desta proposta, é estudar os efeitos da polinização mecânica na produção e qualidade de tomates de três grupos varietais comerciais destinados ao consumo in natura em duas épocas de plantio. O experimento foi conduzido em campo, na Unidade de Pesquisa e Extensão de Hortaliças do Departamento de Fitotecnia da Universidade Federal de Viçosa. O delineamento experimental foi o de blocos casualizados, em esquema fatorial 2 (épocas de plantio) x 2 (polinização natural e polinização mecânica). Os ensaios foram realizados em outono/inverno e verão/outono para cada grupo, avaliando-os separadamente. Foram avaliadas variáveis referentes a: produtividade, qualidade, massa seca de sementes e número de sementes. Observou-se aumento na produtividade com o uso da polinização mecânica em ambas épocas de plantio para os grupos varietais Salada e Italiano, enquanto no grupo Santa Cruz apenas verificou-se esse aumento na época de outono/inverno. A polinização mecânica só aumentou o número de sementes no grupo Salada. Independentemente da época de plantio para os grupos varietais Salada e Italiano, a polinização mecânica atua eficientemente aumentando a produção sem alterar a qualidade do tomate. / The tomato plant is recognized as a model to study the development of the fruit of other species that have anther dehiscence poricida with this being a characteristic which complicates the process of pollination. Mechanical pollination is a practice that facilitates the release of pollen, improving production and quality of fruit. However, reduced information about the efficiency of this type of pollination in fruit production restrict its use. In this sense, the objective of this proposal is to study the effects of mechanical pollination on yield and quality of tomatoes three commercial varieties groups intended for fresh consumption in two planting seasons. The experiment was conducted in the field, the Research Unit and Crop Science Department of Horticultural Extension of the Universidade Federal de Viçosa. The experimental design was in casualised blocks in factorial scheme 2 (planting dates) x 2 (natural pollination and mechanical pollination). The tests were carried out in autumn / winter and summer / fall for each group evaluating them separately. Variables were evaluated regarding: productivity, quality, dry seed weight and number of seeds. If you notice an increase in productivity with the use of mechanical pollination in both planting dates for groups Salada and Italiano, while in Santa Cruz group only there was this increase during the autumn/winter. Mechanical pollination only increase the number of seeds in the group Salada. Regardless of the planting season for the groups Salada and Italiano, mechanical pollination operates efficiently increasing production without changing the quality of the tomatoes.

Salt stress severely constrains plant performance and global agricultural productivity. 5% of arable land, 20% of irrigated areas and 98% of water reserves worldwide are saline. Improving the salt tolerance of major crop species could help attenuate yield losses and expand irrigation opportunities and provide in situ relief in areas where poverty, food and water scarcity are prevalent. Increasing the salt tolerance of crops with high commercial and nutritional value, such as tomato (Solanum lycopersicum L.), would provide particularly significant economic and health benefits. However, salt tolerance is a complex trait with a limited genetic repertoire in domesticated crop varieties, including tomato, frustrating attempts to breed and engineer tolerant crop varieties. Here, a genome-wide association study (GWAS) was undertaken, leveraging the rich genetic diversity of the wild, salt tolerant tomato Solanum pimpinellifolium and the latest phenotyping technologies to identify traits that contribute to salt tolerance and the genetic basis for variation in those traits. A panel of 220 S. pimpinellifolium accessions was phenotyped, focusing on image-based high-throughput phenotyping over time in controlled and field conditions in young and mature plants. Results reveal substantial natural variation in salt tolerance over time across many traits. In particular, the use of unmanned aerial vehicle (UAV)-based remote sensing in the field allowed high-resolution RGB, thermal and hyperspectral mapping that offers new insights into plant performance in the field, over time. To empower our GWAS and facilitate the identification of candidate genes, a new S. pimpinellifolium reference genome was generated, 811Mb in size, N50 of ~76kb, containing 25,970 annotated genes. Analysis of this reference genome highlighted potential contributors to salt tolerance, including enrichments in genes with stress response functions and a high copy number of the salt tolerance-associated gene inositol- 3-phosphate synthase (I3PS). A recently completed full genome re-sequencing of the panel, along with a newly available pseudomolecule-level assembly of the S. pimpinellifolium genome with N50 of ~11Mb, will serve to drive a GWAS to identify loci associated with traits that contribute to salt tolerance. Further research including gene validation, breeding, genetic modification and gene editing experiments will drive the development of new salt tolerant tomato cultivars.

Monoploid potato genotypes represent plant material that is free from the "genetic load" of lethal and severely deleterious alleles normally present in the highly heterozygous cultivated potato species. Field evaluations enabled the identification of agronomically superior monoploid potato genotypes from a population of more than 100 anther-derived monoploids. Chemical fusion and electrofusion between pairs selected from 31 superior monoploids resulted in the production of three different groups of intermonoploid somatic hybrids. The hybridity of somatic hybrid plants and calluses was confirmed through PCR-based amplification of simple sequence repeat (SSR) sequences in the potato genome. Polymorphic SSR loci between the monoploid parents of a particular group of somatic hybrids were used to separate true somatic hybrids (heterozygous at the loci) from parental somaclones regenerating from unfused protoplasts (homozygous for one parental band at the loci). One group of somatic hybrids (SH1, SH2 and SH2B) was of particular interest because it resulted from the fusion of a S. phureja monoploid to a high acetylleptinidine-producing monoploid derived from an F1 hybrid between S. chacoense and S. phureja. The leptine acetylleptinidine (ALD) is produced only by some accessions of S. chacoense Bitt. and provides resistance to feeding by the Colorado potato beetle (Leptinotarsa decemlineata Say) when present in sufficient concentrations. The somatic hybrids produced moderate levels of ALD in leaves and stems (roughly 60% that of a high ALD-producing S. chacoense clone). Pollinations of SH1, SH2 and SH2B by several diploid and tetraploid potato clones resulted in three fruit on SH2, one fruit on SH2B and no fruit on SH1. Two resulting progeny populations of SH2 [SH2A = SH2 × S. andigena 8-1 (4x); SH2P = SH2 × S. phureja 66AP11-53 (2x)] expressed higher fertility than the original somatic hybrids and were sexually crossed as both male and female parents to S. tuberosum cv. Atlantic. All of the SH2 progeny populations expressed acetylleptinidines, albeit at lower levels than the SH2 somatic hybrid, providing strong evidence that the genes controlling acetylleptinidine production are dominant. Variation for ALD expression in the SH2 progeny indicated one or a few genes with additive effect controlling the ALD trait. In addition, the choice of male parent in sexual crosses to SH2 affected subsequent ALD expression in progeny populations. The SH2 progeny represent an important first step towards transferring acetylleptinidines to cultivated potato. SH1, SH2 and SH2B appeared to be negatively affected by an unusually high ploidy (hexaploid, 6x). Field-grown plants produced many tubers (mean = 35) of low weight (mean = 10.4 g) and were stunted in appearance. Anther culture of SH2 yielded triploid regenerants (3x). These regenerants may be more phenotypically normal than the original somatic hybrids because of lower ploidy. Segregation of SSR alleles in the triploid anther culture regenerants provided evidence that the hexaploid somatic hybrid SH2 genome is comprised of four homologous genomes of CP2-103 (the high leptine-producing monoploid) and two homologous genomes of 13-14 203 (the S. phureja monoploid). / Master of Science

The potato (Solanum tuberosum L.) crop serves as a staple food worldwide and is capable of reducing the world’s food shortages because unlike cereals and other agricultural crops, it is less affected by prices in the international markets. Research on alleviation of food crises suggested root and tuber crops such as potatoes to be the solution to the problem of food shortage. The crop is widely cultivated but is difficult to produce due to susceptibility to numerous pests and pathogenic organisms, as well as abiotic stresses. To control these pests and diseases, strategies to limit susceptibility to factors that interfere with the growth and development of plants, or breeding new varieties that are able to withstand stresses are being researched. Recent studies have shown that non essential nutrients such as Silicon (Si) are beneficial to plants in terms of yield, protection from fungal diseases and improved uptake of phosphorus. Since very little research has focused on the role of Si in improving potato production, three glasshouse pot trials were conducted at the Hatfield Experimental farm and Department of Plant Pathology glasshouses of the University of Pretoria to evaluate the effect of various soil amendments on potato yield and quality. The effect of these soil amendments on pH was also investigated as P-uptake and development of common scab in potatoes are pH dependent. The soil amendments consisted of different silicon sources and an agricultural lime. The Si sources were Calmasil slag (Middleburg) (30% Si- containing liming material), fly ash (50% Si nonliming material), and Si fume/ash (99% Si non-liming material). Agricultural lime (CaCO3) was included as a control. The purpose of the first two trials was to identify the most promising silicon-containing source for potato production, while the third trial evaluated the effect of this silicon source on soil pH and potato tuber yield. In all three trials, agricultural lime was used as a control. Due to the high demand for nutrients by the potato crop, other nutrient elements were added to the soil through fertigation every 7 to 14 days, depending on the growth stage of the plants. Plants were irrigated with distilled water when necessary to maintain an adequate moisture level i.e. moist but not too wet. Weekly observations on growth parameters were made. To select the most promising soil amendment, parameters such as leaf chlorophyll content, plant height, tuber number and mass (Fwt), fresh and dry weight (top growth) and change in soil pH were analyzed. Slag treated plants tended to produce tubers with higher mass and better appearance. In this study the highest increase in soil pH was observed in soil mixed with slag, compared to all the other silicon sources. Although there was no significant difference observed among treatments there was a distinct difference in plant growth between trials when soil was amended with lime and slag. Plants treated with slag tended to produce tubers that weigh more, whilst plants treated with lime grew taller and had the highest tuber number. There was a significant rise in soil pH from both lime and slag, which might have in turn influenced vegetative and tuber growth. / Dissertation (MInst(Agrar)--University of Pretoria, 2013. / gm2014 / Plant Production and Soil Science / unrestricted

The aim of our diploma thesis was to evaluate the influence of drop irrigation on achieved profit and the quality of chosen consumable variety of potatoes. The field experiment was established on lands of experimental field station AF MENDELU in Žabčice, Brno during a trial period from 2016 to 2017. Two consumable varieties of potatoes with different duration of vegetative period – very early season variety called Monika and mid-early season variety called Jolana – were used for experiments. The influence of additional drop irrigation on profit and strachiness of potatoe tubers was closely monitored. The experiment consisted of four options, always in four repetitions. Particular options were: Control, P60, P65 and P70% of usable water capacity. On the basis of attained results it is possible to note that the drop irrigation is very effective and efficient way to raise profit and quality of potatoes. Due to practical and economic reasons, P60 and P65 appear to be an optimal option of drop irrigation providing medium soil humidity.

Zinc oxide nanoparticles are highly variable materials capable of producing positive and negative responses to their effects on plants. Negative effects are often associated with their excessive concentration, which can cause oxidative stress in plants.Conversely, suitable dosages lead to positive manifestations of growth and improvement in the properties studied. ZnO nanoparticles provide plants with a more acceptable form of zinc that is well accessible and easier to use. However, information about their pos-sible toxic effect in combination with another stress factor is lack. The aim of this work was to compare and evaluate the effects of zinc in the form of nanoparticles (ZnO NPs) with the effects of zinc bound in chelate bonding (Zn-EDTA), in combination with UV-C stress factor in plants Solanum lycoperscicum L. Results of this pilot experiment show that both ZnO and Zn-EDTA nanoparticles of 10.95 mg Zn2+ /l in combination with UV-C radiation have a negative effect on vitality and induce oxidative stress in treated plants. The decisive effect on the toxic effect was based on the concentration used and the form of zinc applied. Differences were expres-sed in expression levels of genes affected by oxidative stress. The results obtained from the expression analysis of the genes made it possible to observe the individual transcripts used to respond to oxidative stress and also to provide information on the possible sy-nergistic effect of UV-C radiation and zinc in both studied forms (Zn-EDTA and ZnO NPs).

N-acylethanolamines (NAEs) are fatty acid ethanolamides that occur in a wide range of eukaryotes and their composition is specific to species, developmental stage and tissue type. In plants, NAEs negatively regulate growth and mediate stress responses. The function of NAEs is terminated by a highly conserved enzyme fatty acid amide hydrolase (FAAH). In plants, FAAH homologue has been characterized only for model plant Arabidopsis. Under normal growth conditions, AtFAAH overexpressor seedlings showed enhanced growth suggesting that FAAH might act as a modulator of endogenous NAE levels and regulate growth. Because of the significant role NAEs were shown to play in model plant Arabidopsis, it is pertinent to elucidate this conserved metabolic pathway in crop species such as tomato (Solanum lycopersicum) that may lead to improved productivity. We hypothesized that there is a functional FAAH in tomato that hydrolyzes NAEs. With AtFAAH as a template and using BLASTX, we identified two putative FAAH sequences in tomato. CLUSTALW alignment showed conserved amidase signature sequence and the catalytic triad. Molecular visualization system (PyMOL) revealed that the protein structures of putative SlFAAH1and 2 were similar in domain structure to AtFAAH, with minor differences in spatial arrangement. For further biochemical characterization, full-length coding sequence of SlFAAH1 and SlFAAH2 were isolated and cloned into a heterologous expression system. The expressed protein will be characterized for its hydrolytic activity against radiolabelled NAE substrates. This research is expected to lead to characterization of NAE pathway in a crop plant. Long-term implications of this study include development of molecular and biochemical tools necessary to improve tolerance to abiotic stress and increase crop productivity.