Please read the abstract in the section 00front of this document / Dissertation (MSc Agric (Agronomy))--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

M.S.

No abstract available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 28, 2007) Vita. Includes bibliographical references.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Objetivou-se com este trabalho determinar a qualidade física e fisiológica de dez lotes de sementes de Acacia mangium Willd provenientes de plantios comerciais com diferentes idades estabelecidos na savana de Roraima. Os frutos foram coletados de plantios localizados na Serra da Lua, nos municípios do Cantá e Bonfim, de plantas com 4, 5, 7, 9 e 10 anos de idade. As sementes das cinco idades, após a determinação da massa de 1000 sementes, foram classificadas em pequenas e grandes, formando 10 lotes de sementes. O teste de germinação foi realizado, após a superação da dormência, em quatro repetições de 50 sementes, por lote, sobre papel de germinação e mantidos em gerbox a 25C. A embebição foi observada nos tempos 0, 1, 3, 5, 8, 12, 16, 24, 48, 60, 72, 96 e 120 horas para sementes colocadas entre papel. O teste de envelhecimento acelerado foi conduzido em gerbox, em quatro repetições de 50 sementes, mantidos em BOD a 41C por 0, 24, 48 e 72 horas. O teste de condutividade elétrica foi realizado com sementes sem e com a superação da dormência, em quatro repetições de 50 sementes imersas em 75 mL de água por 24 horas. As sementes de A. mangium não apresentam o padrão trifásico de absorção de água em 120 horas após a superação da dormência. Sementes pequenas de acácia, após a superação da dormência, absorvem mais água e apresentam maior média de porcentagem e velocidade de germinação inicial e menor tempo médio de germinação que sementes grandes. A exposição de sementes de A. mangium por 24 horas no envelhecimento acelerado reduz a porcentagem e velocidade de germinação e aumenta a porcentagem de sementes mortas e de plântulas anormais. A imersão das sementes em 75 mL de água por 24 horas a 25C resultam em valores de condutividade elétrica sem relação com a germinação. A idade da planta não apresenta relação com a massa de 1000 sementes e com a absorção de água em 120 horas, para sementes submetidas à superação da dormência. Sementes de plantas com 10 anos apresentam maior porcentagem e velocidade de germinação que sementes de plantas com 4 anos de idade. / The objective of this work was determinate the physic and physiologic quality of ten lots of Acacia mangium Willd. from different commercial established plant ages in Roraimas savanna. Fruits were collected from plantations in Serra da Lua, in Cantá and Bonfim, from plants with 4, 5, 7, 9 and 10 years-old. Seeds from five plant ages, after the determinations of 1000 seeds weight, were classified in small and large, composing 10 lots. Germination test has been done, after dormancy overcoming, in four repetitions with 50 seeds, per lot, above germination paper and inside gerbox in 25C. The imbibition was observed in the times 0, 1, 3, 5, 8, 12, 16, 24, 48, 60, 72, 96 and 120 hours to seeds put between papers. The Seed aging test was made in gerbox in four repetitions with 50 seeds, maintained in BOD in 41C for 0, 24, 48 and 72 hours. The electrical conductivity test was made to seeds without and with dormancy overcoming, in four repetitions with 50 seeds immersed in 75 mL of water for 24 hours. Seeds of A. mangium do not exhibit the three-stage water absorption process in 120 hours, after dormancy overcoming. Small seeds of acacia, after dormancy overcoming, absorb more water and show higher mean of percentage and speed of initial germination and lower time mean of germination than large seeds. Exposition the A. mangium seeds for 24 hours in seed age test reduces the percentage and speed of germination and increases the percentages of dead seeds and abnormal seedlings. The immersion of the seeds in 75 mL of water for 24 hours in 25C results in value of electrical conductivity with no relation to germination. The plant age do not show relation to 1000 seeds weight and to water absorption process for 120 hours, from seeds submitted to dormancy overcoming. Seeds from plants with 10 years-old show higher percentage and speed of germination than seeds from plants with 4 years-old.

Thesis (M. A. Agricultural Management (Agricultural Extension)) -- University of Limpopo, 2019 / Smallholder farmers’ need for regular supply of adequate, quality and affordable seed led to the establishments of Community-Based Maize Seed Production Schemes (CBSPSs) in most developing countries, including South Africa. In view of the important influence of perception on the adoption and continued use of an innovation, this study was undertaken to evaluate farmers’ perceptions of CBSPSs in Polokwane and Lepelle-Nkumpi Local Municipalities of Limpopo province. The conceptualization of perception used in this study was based on the Düvel (1991) framework. The evaluation focused on whether planting the scheme’s main product, improved Open-Pollinated Varieties (improved OPV maize) seed meets farmers’ needs based on their perceptions and the extent of farmers’ planting of improved OPV maize. A census approach was used in view of the small numbers of seed producers in the schemes; all scheme members (50) were, therefore, interviewed between 27 March and 21 April 2017. To allow for comparison, an equal number of farmers (50) who were not members of the scheme were also interviewed. Data was collected from farmers using a semi-structured questionnaire. Descriptive and inferential statistics were applied to analyze the data using SPSS software. A binary logistic model was used to analyze factors that influence farmer perceptions on OPV benefits. The study findings showed that there is a significant relationship between awareness knowledge of improved OPV maize and planting of improved OPV maize. Furthermore, the results showed that farmers perceptions of the advantages and disadvantages of improved OPV maize seed were not different among scheme and non-scheme members as they were all in agreement that improved OPV maize have more benefits than their own previously recycled seeds. Finally, findings showed that respondents municipality and scheme membership had a significant, effect on the positive perception of planting improved OPV maize seeds. Other explanatory variables such as sex, farming experience, years of viii schooling, farm size, income and age of participants had no significant effect on farmer perceptions. It is therefore recommended that improved OPV maize be made widely available and promoted based on its advantages to enhance its adoption. Future studies on these seed schemes could look into the production and financial analysis of CBSPSs to ascertain their profitability and sustainability. / Agricultural Research Council (ARC)

Thesis (M. Tech. Agriculture) -- Central University of Technology, Free state, 2012 / A series of incubation studies and greenhouse experiments were conducted to evaluate the use of EM seed treatments, at different application levels, handling techniques and soil conditions on germination and seedling vigour of selected cultivars of maize, sorghum and sunflower. Two incubation studies were conducted to evaluate the germination and seedling vigour of maize, sorghum and sunflower seeds treated with M-EM from three different suppliers, multiplied at two different ratios (1% and 3%) and diluted at three different levels (0.01%, 0.1% and 1.0%) compared to a control treated with pure water. Results revealed no significant differences under optimum germination conditions, while seedlings under cold stress indicated that M-EM treatments positively affected germination and seedling vigour compared to the control treatments. Two incubation studies were also conducted to evaluate the germination and seedling vigour of maize, sorghum and sunflower seeds treated with M-EM from three different suppliers, multiplied at two different ratios (1% and 3%) and exposed to the influences of irradiation and temperature fluctuation. From the results became clear that the correct storage and handling is essential in optimizing the effect of M-EM on seeds. Even though M-EM was exposed to irradiation and temperature fluctuation, M-EM still had positive effects on germination and seedling vigour. Pot experiments were conducted to determine the effect of EM as seed treatment, at different dilutions, on germination, seedling vigour and dry mass of maize, sorghum and sunflower at different planted depths. Germination were not affected by the M-EM treatment, while shoot length results indicated that seed treated with M-EM could have significant effect on seedling survival. A greater effect was visible on the shoot length of shallow planted seeds, than on deeper planted seeds. From the results no single company, ratio or dilution could be prescribed as paramount. To further investigate the effect of M-EM subjected to the influences of irradiation and temperature fluctuation; maize, sorghum and sunflower seeds were treated with M-EM from three different suppliers, multiplied at two different ratios (1% and 3%) and exposed to the influences of irradiation and temperature fluctuation and planted in soil. M-EM treatments only benefited the germination of deeper planted sorghum seeds compared to the control treatments. The shoot lengths of deeper planted maize and sunflower seed were positively increased by the M-EM treatments while also resulting in significant results for the overall shoot length of sorghum. The third pot study was conducted to determine the influence of EM as a seed treatment on maize, sorghum and sunflower planted in three different soils, namely: sterilized soil, soil treated with M-EM and Fusarium containing soil. Germination and seedling vigour results of the sterilized and M-EM treated soil revealed to be superior to that of the Fusarium containing soil. From the results was concluded that M-EM treatments will probably improve early seedling growth of maize, sorghum and sunflower compared to untreated seed and that M-EM seed treatment and a pre-plant EM soil treatment might assist seeds in unfavourable germination and growth conditions.

Uma das técnicas de restauração ecológica de vegetação nativa testada é a semeadura direta ou plantio de sementes, que pode diminuir custos, facilitar a implantação e a adaptação rápida da espécie ao ambiente comparando ao plantio de mudas. Porém, essa técnica não suplantou o plantio de mudas e um dos questionamentos é sobre abaixa germinação das sementes e do desconhecimento das práticas adequadas de semeio. Portanto, nessa pesquisa avaliaram-se a qualidade, características e desempenho de sementes de cinco espécies florestais nativas, testando também algumas técnicas de semeio no campo. As sementes utilizadas são de espécies arbóreas de recobrimento: Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum e Trema micrantha de dois lotes (um comprado no mercado e outro colhido pelo pesquisador no campo).A qualidade dessas sementes foi determinada por meio dos parâmetros físicos: pureza, teor de água, massa de mil sementes, largura, comprimento, área, circularidade, cor (sistemas RGB e banda G), peso e densidade aparente; fisiológicos: a velocidade e a taxa de emergência das plântulas e sanitário: avaliação dos fungos presentes nas sementes. Métodos para o beneficiamento dos lotes de sementes, a partir dos parâmetros físicos foram testados. E foram avaliadas a profundidade de semeadura e a emergência das plântulas das sementes tratadas e não-tratadas através do priming, testados em laboratório e em campo. A caracterização física dos lotes (comprado e colhido) foi semelhante (pureza e teor de água), as outras medidas físicas foram em geral diferentes entre os lotes e geralmente maiores para o lote colhido, e apenas para a G. ulmifolia o lote comprado foi superior. Fisiologicamente, os lotes (comprado e colhido) foram similares, porém o lote de G. ulmifolia comprado e de T. micrantha colhido emergiram mais, e as demais espécies foram semelhantes. O mesmo pode-se afirmar para o índice de velocidade de emergência das plântulas (IVEP), que também foram semelhantes entre os lotes, mas não para TMEP (Tempo Médio de Emergências das Plântulas). Para sanidade, os lotes colhidos obtiveram menor incidência de fungos fitopatogênicos. A densidade aparente foi a variável mais correlacionada com a emergência das sementes. Já as melhores profundidades de semeadura foram de 1 cm para a S. granulosoleprosum, 2 cm para a G. ulmifolia e de 1-2 cm para as demais espécies. O priming foi significativo, em laboratório, para C. floribundus em emergência, IVEP e TMEP, e T. micrantha em IVEP. Em campo, o priming reduziu o TMEP de C. floribundus e de T. micrantha, e melhorou o IVEP desta. As espécies mais recomendadas para semeadura direta a partir da emergência em campo são: S. granulosoleprosum >C. floribundus >G. ulmifolia >C. urucurana >T. micrantha. O monitoramento de emergência das plântulas pode ser realizado em 50 dias para S. granulosoleprosum, 65 dias para T. micrantha e 30 dias para as demais. Concluem-se que os lotes (comprados ou colhidos) são adequados, o uso da densidade aparente é o melhor método de beneficiamento e não houve benefícios significativos com o priming. Essas práticas podem ser empregadas em semeadura direta em restauração ecológica. / One of ecological restoration techniques for native vegetation tested is the direct sowing or planting seeds, which can lower costs, easy deployment and rapid adaptation of species to the environment compared to planting seedlings. However, this technique does not supplanted the planting of seedlings and one of the questions is on the low germination of native species and the lack of best practices of sowing. Therefore, in this study it was evaluated the quality, features and performance of five native species seeds, also testing some sowing techniques in the field. The seeds used were tree species filling, Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum and Trema micrantha two lots (one purchased in the market and another collected by the researcher in the field). The quality of these seeds was determined by the physical parameters: purity, water content, mass of thousand seeds, width, length, area, roundness, color (RGB systems and G band), weight and specific gravity; Physiological: the speed and the emergence rate of seedlings and health: assessment of fungi present in the seeds. Methods for processing of seed lots, from the physical parameters had tested. And it evaluated the depth of sowing and seedling emergence of seeds treated and non-treated by priming, tested in laboratory and on field. Physical characteristics of the lots (purchased and harvested) was similar (purity and water content), other physical measurements were generally different between lots and generally larger for the lot harvested, and only for the G. ulmifolia purchased lot was higher. Physiologically, lots (purchased and harvested) were similar, but G. ulmifolia purchased lot emerged more and T. micrantha harvested lot was better, and the other species were similar. The same said for the seedling emergence speed index (SESI), which were also similar between lots, but not for MTES (Mean Time Emergencies of Seedlings). For sanity, lots harvested was lower incidence of pathogenic fungi. The specific gravity was the most correlated variable with the emergence of seeds. Already the best sowing depths were 1 cm for S. granulosoleprosum, 2 cm to G. ulmifolia and 1-2 cm for other species. The priming was significant in the laboratory for C. floribundus in emergency, SESI and MTES, and T. micrantha in SESI. In the field, the priming reduced the MTES for C. floribundus and T. micrantha, and improved SESI this. The most recommended species for direct sowing on field in emergency are: S. granulosoleprosum>C. floribundus>G. ulmifolia>C. urucurana>T. micrantha. The emergency monitoring of seedlings can be done in 50 days for S. granulosoleprosum, 65 days for T. micrantha and 30 days for the other. To conclude that lots (purchased or harvested) are suitable, the use of the specific gravity is the best processing method and no significant benefits with priming. These practices may be employment in direct sowing in ecological restoration.

Uma das técnicas de restauração ecológica de vegetação nativa testada é a semeadura direta ou plantio de sementes, que pode diminuir custos, facilitar a implantação e a adaptação rápida da espécie ao ambiente comparando ao plantio de mudas. Porém, essa técnica não suplantou o plantio de mudas e um dos questionamentos é sobre abaixa germinação das sementes e do desconhecimento das práticas adequadas de semeio. Portanto, nessa pesquisa avaliaram-se a qualidade, características e desempenho de sementes de cinco espécies florestais nativas, testando também algumas técnicas de semeio no campo. As sementes utilizadas são de espécies arbóreas de recobrimento: Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum e Trema micrantha de dois lotes (um comprado no mercado e outro colhido pelo pesquisador no campo).A qualidade dessas sementes foi determinada por meio dos parâmetros físicos: pureza, teor de água, massa de mil sementes, largura, comprimento, área, circularidade, cor (sistemas RGB e banda G), peso e densidade aparente; fisiológicos: a velocidade e a taxa de emergência das plântulas e sanitário: avaliação dos fungos presentes nas sementes. Métodos para o beneficiamento dos lotes de sementes, a partir dos parâmetros físicos foram testados. E foram avaliadas a profundidade de semeadura e a emergência das plântulas das sementes tratadas e não-tratadas através do priming, testados em laboratório e em campo. A caracterização física dos lotes (comprado e colhido) foi semelhante (pureza e teor de água), as outras medidas físicas foram em geral diferentes entre os lotes e geralmente maiores para o lote colhido, e apenas para a G. ulmifolia o lote comprado foi superior. Fisiologicamente, os lotes (comprado e colhido) foram similares, porém o lote de G. ulmifolia comprado e de T. micrantha colhido emergiram mais, e as demais espécies foram semelhantes. O mesmo pode-se afirmar para o índice de velocidade de emergência das plântulas (IVEP), que também foram semelhantes entre os lotes, mas não para TMEP (Tempo Médio de Emergências das Plântulas). Para sanidade, os lotes colhidos obtiveram menor incidência de fungos fitopatogênicos. A densidade aparente foi a variável mais correlacionada com a emergência das sementes. Já as melhores profundidades de semeadura foram de 1 cm para a S. granulosoleprosum, 2 cm para a G. ulmifolia e de 1-2 cm para as demais espécies. O priming foi significativo, em laboratório, para C. floribundus em emergência, IVEP e TMEP, e T. micrantha em IVEP. Em campo, o priming reduziu o TMEP de C. floribundus e de T. micrantha, e melhorou o IVEP desta. As espécies mais recomendadas para semeadura direta a partir da emergência em campo são: S. granulosoleprosum >C. floribundus >G. ulmifolia >C. urucurana >T. micrantha. O monitoramento de emergência das plântulas pode ser realizado em 50 dias para S. granulosoleprosum, 65 dias para T. micrantha e 30 dias para as demais. Concluem-se que os lotes (comprados ou colhidos) são adequados, o uso da densidade aparente é o melhor método de beneficiamento e não houve benefícios significativos com o priming. Essas práticas podem ser empregadas em semeadura direta em restauração ecológica. / One of ecological restoration techniques for native vegetation tested is the direct sowing or planting seeds, which can lower costs, easy deployment and rapid adaptation of species to the environment compared to planting seedlings. However, this technique does not supplanted the planting of seedlings and one of the questions is on the low germination of native species and the lack of best practices of sowing. Therefore, in this study it was evaluated the quality, features and performance of five native species seeds, also testing some sowing techniques in the field. The seeds used were tree species filling, Croton floribundus, Croton urucurana, Guazuma ulmifolia, Solanum granulosoleprosum and Trema micrantha two lots (one purchased in the market and another collected by the researcher in the field). The quality of these seeds was determined by the physical parameters: purity, water content, mass of thousand seeds, width, length, area, roundness, color (RGB systems and G band), weight and specific gravity; Physiological: the speed and the emergence rate of seedlings and health: assessment of fungi present in the seeds. Methods for processing of seed lots, from the physical parameters had tested. And it evaluated the depth of sowing and seedling emergence of seeds treated and non-treated by priming, tested in laboratory and on field. Physical characteristics of the lots (purchased and harvested) was similar (purity and water content), other physical measurements were generally different between lots and generally larger for the lot harvested, and only for the G. ulmifolia purchased lot was higher. Physiologically, lots (purchased and harvested) were similar, but G. ulmifolia purchased lot emerged more and T. micrantha harvested lot was better, and the other species were similar. The same said for the seedling emergence speed index (SESI), which were also similar between lots, but not for MTES (Mean Time Emergencies of Seedlings). For sanity, lots harvested was lower incidence of pathogenic fungi. The specific gravity was the most correlated variable with the emergence of seeds. Already the best sowing depths were 1 cm for S. granulosoleprosum, 2 cm to G. ulmifolia and 1-2 cm for other species. The priming was significant in the laboratory for C. floribundus in emergency, SESI and MTES, and T. micrantha in SESI. In the field, the priming reduced the MTES for C. floribundus and T. micrantha, and improved SESI this. The most recommended species for direct sowing on field in emergency are: S. granulosoleprosum>C. floribundus>G. ulmifolia>C. urucurana>T. micrantha. The emergency monitoring of seedlings can be done in 50 days for S. granulosoleprosum, 65 days for T. micrantha and 30 days for the other. To conclude that lots (purchased or harvested) are suitable, the use of the specific gravity is the best processing method and no significant benefits with priming. These practices may be employment in direct sowing in ecological restoration.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-07-05T14:54:04Z No. of bitstreams: 1 ACÁCIO FIQUEIRÊDO NETO - DISSERTAÇÃO PPGEA 2003..pdf: 4578217 bytes, checksum: 9dbfdf653e3c7c4bbe60a1bba3c2f1ff (MD5) / Made available in DSpace on 2018-07-05T14:54:04Z (GMT). No. of bitstreams: 1 ACÁCIO FIQUEIRÊDO NETO - DISSERTAÇÃO PPGEA 2003..pdf: 4578217 bytes, checksum: 9dbfdf653e3c7c4bbe60a1bba3c2f1ff (MD5) Previous issue date: 2003-07 / No processamento de sementes, logo após a colheita e debulha, estas são encaminhadas a Usina de Beneficiamento de Sementes (UBS), onde através de elevadores são conduzidas às máquinas de pré-limpeza, limpeza, separação e classificação, tratamento, embalagem e transporte para o armazenamento. O presente trabalho foi desenvolvido para investigar os impactos mecânicos sofridos pelas sementes de duas variedades de feijão vigna (Cedinha e Rabo de Tatu) com dois teores de umidade (13,5% e 7,3% b.u.) ao passarem pelas operações impostas depois da colheita, debulha e pela UBS e suas consequências no decorrer do armazenamento. Foram utilizadas as sementes com pureza acima de 95%, as quais foram submetidas às operações da UBS. Ao longo do sistema de operação foram coletadas amostras para analisar e verificar os danos devidos aos impactos mecânicos. As amostras de trabalho foram logo submetidas aos testes de germinação e aos diferentes testes de vigor. E, em seguida, outras amostras foram armazenadas nas condições ambientais de Alagoinha - PB, e nas condições controladas de câmara seca em Campina Grande - PB. As sementes com a umidade 7,3% da variedade Rabo de Tatu são mais susceptíveis a quebra ocasionada pelos impactos durante o processo de beneficiamento; as sementes das duas variedades estudadas, demonstraram ante o tempo de armazenamento, os impactos sofridos e os teores de umidade iniciais, tendências e um mesmo comportamento, embora quantitativamente diferentes e que os impactos sofridos pelas sementes na UBS durante o seu beneficiamento não exerceram efeitos imediatos sobre a germinação e o vigor das sementes. O teste de vigor que melhor correlacionou com o teste padrão de germinação (TPG) foi o índice de velocidade de emergência (IVE), com um coeficiente de correlação acima de 97%, podendo ser empregado na avaliação do vigor dessas sementes. / In the processing of seeds, soon after the crop and it thrashes, these are directed tha Plant of Improvement of Seeds, where through elevators the machines of before-cleaning, cleaning, separation and classification, treatment, packing and storage are led. This work was developed to investigate the mechanical impacts suffered by the seeds of two varieties of bean vigna (Cedinha and Rabo of Tatu) with two moisture contents (13,5% and 7,3% w.b.) to the they go by the operations imposed after the crop and it thrashes and your consequences in elapsing of the storage. The seeds were used with purity above 95%, so that it could submit them the operations of Plant of Improvement of Seeds. In each operation place samples were collected to analyze and to veriíy the damages happened through the impacts. The work samples were soon submitted to the germination tests and the different vigor tests. And, soon after, other samples were stored in the environmental conditions of Alagoinha - PB, and in the controlled conditions of camera it evaporates in Campina Grande - PB. The seeds with the humidity 7,3% of the variety Rabo de Tatu are more fragile the break caused by the impacts during the improvement process; the seeds of the two studied varieties, demonstrated in the face of the time of storage, the suffered impacts and the initial humidity tenors, tendencies and a same behavior, although with different amounts although with different amounts and that the suffered impacts for the seeds during your improvement didn't exercise immediate effects on the germination and the vigor of the seeds. The vigor test that best correlated with the standard test of germination it was the index of emergency speed, with a correlation coefficient above 97%, could be used in the evaluation of the vigor of those seeds.