Teses / dissertações sobre o tema "Controlled germination"

Submitted by ERIKA OLIVEIRA DA SILVA (erikaagro@gmail.com) on 2018-08-24T14:30:24Z No. of bitstreams: 1 Tese Érika Final Conferida com ficha (1).pdf: 975581 bytes, checksum: c0158160c152b2695ba62e395d73b676 (MD5)<br>Approved for entry into archive by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-08-24T15:28:34Z (GMT) No. of bitstreams: 1 silva_eo_dr_botfca.pdf: 975581 bytes, checksum: c0158160c152b2695ba62e395d73b676 (MD5)<br>Made available in DSpace on 2018-08-24T15:28:34Z (GMT). No. of bitstreams: 1 silva_eo_dr_botfca.pdf: 975581 bytes, checksum: c0158160c152b2695ba62e395d73b676 (MD5) Previous issue date: 2018-06-25<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>A pinta bacteriana do tomateiro, causada por Pseudomonas syringae pv. tomato Okabe (Pst), é uma das principais doenças da cultura, pois pode reduzir a qualidade e o rendimento da produção, afetando o mercado de tomates frescos e transformados. A semente de tomate infectada por Pst, além de manter a bactéria viável por um longo período, também é importante por ser uma fonte primária de inóculo, justificando a necessidade de utilização de sementes isentas do patógeno. Desse modo, esse trabalho teve como objetivos avaliar a eficiência da termoterapia e da aplicação de óleos essenciais como alternativas para o tratamento de sementes de tomate, visando ao manejo de Pst. Inicialmente, foi verificada a ação in vitro dos óleos essenciais (OE) de citronela (Cymbopogon nardus (L.) Rendle), capim-limão (Cymbopogon citratus (DC.) Stapf), tomilho (Thymus vulgaris L.) e melaleuca (Melaleuca alternifolia Cheel), nas concentrações de 1%, 2% e 3%, utilizando-se leite em pó (LP - 1%) como emulsificante. Sulfato de estreptomicina (25mg/mL) e água esterilizada + LP foram incluídos como testemunhas. Os OE de tomilho (2 e 3%) e de citronela (nas três concentrações) e o sulfato de estreptomicina inibiram o desenvolvimento da colônia bacteriana, promovendo a formação do halo de inibição. Em seguida, foram conduzidos experimentos independentes, um para testar o tratamento de sementes com os OE selecionados (citronela a 1% e tomilho a 2%) e outro, com a termoterapia (50°C/30’ e 50°C/25’). Todos os experimentos foram realizados em duplicata. Foram avaliados a incidência de Pst nas sementes, a germinação e o vigor (altura de plantas). Todos os tratamentos testados promoveram a erradicação de Pst nas sementes. A presença de Pst nas sementes não interferiu na germinação destas, mas promoveu uma redução na altura das plantas. O tratamento com OE de tomilho resultou em redução significativa da germinação e do vigor. Os tratamentos térmico (ambas as combinações temperatura/tempo de exposição) e com óleo essencial de citronela a 1% mostraram-se alternativas viáveis para o manejo de Pst em sementes de tomate.<br>The bacterial speck of tomato, caused by the bacterium Pseudomonas syringae pv. tomato (Pst), is among the main diseases of this crop, as it can reduce the quality and production yield, affecting the market of fresh and processed tomatoes. Pstinfected tomato seed, besides maintaining the bacterium viable for a long period, is also important because it is a primary source of inoculum, demonstrating the need of using Pst-free seeds. Thus, the objective of this work was to evaluate the efficiency of thermotherapy and the application of essential oils as alternatives for tomato seeds treatment, aiming at the management of Pst. Initially, the essential oils (EO) of citronella, lemon grass, thyme and tea tree were evaluated in concentrations of 1%, 2% and 3% (powder milk (PM - 1%) was used as emulsifier). Streptomycin sulfate (25mg/mL) and sterile water + PM were included as controls. Thyme (2% and 3%) and citronella (at three concentrations) EO and streptomycin sulfate inhibited the bacterial colonies development, promoting inhibition halo the formation. Then, independent experiments were carried out, one to test the seed treatment with the selected EOs (citronella 1% and thyme 2%) and another with thermotherapy (50°C/30' and 50°C/25'). All experiments were performed in duplicate. The incidence of Pst in seeds, germination and vigor (plant height) were evaluated. All the tested treatments promoted the eradication of Pst in the seeds. Pst presence in the seeds did not interfere in seeds germination, but promoted a reduction in plant height. Treatment with thyme EO resulted in a significant germination and vigor reduction. Thermal treatments (both temperature/exposure time combinations) and 1% citronella EO were found to be viable alternatives for Pst management in tomato seeds.

Orientador: José Buratini Júnior<br>Resumo: Na produção in vitro (IVP), trabalha-se com uma população de oócitos heterogênea em relação ao estágio da maturação nuclear que estes oócitos se encontram, mais especificamente o estágio de vesícula germinativa (GV), uma vez que estes são obtidos de folículos em diferentes estágios de desenvolvimento. Visto que essa heterogeneidade impacta nos resultados da IVP, torna-se necessário que os processos de seleção de oócitos e de maturação in vitro sejam adequados e articulados, para que ocorra o desenvolvimento da competência oocitária para subsequente desenvolvimento. Neste estudo, objetivou-se avaliar a população de ovócitos obtida de folículos antrais grandes, testando a hipótese de que folículos dominantes saudáveis conteriam oócitos com grau intermediário de compactação da cromatina (oócitos em GV2). Em seguida, avaliou-se a população de oócitos obtida em dia aleatório do ciclo estral após OPU e testou-se o efeito de protocolo de sincronização combinando aspiração de folículos e tratamento com FSH para homogeneizar a população e controlar a qualidade dos oócitos. Os resultados sugerem que folículos dominantes saudáveis são predominantemente compostos por oócitos com níveis intermediários de compactação da cromatina e que protocolos de sincronização de aspiração do folículo combinadas ao tratamento com FSH podem ser úteis para controlar a qualidade do oócito para OPU / IVP.<br>Abstract: In vitro production (IVP), a heterogeneous oocyte population is employed in relation to the stage of nuclear maturation that these oocytes are found, more specifically the germinal vesicle (GV) stage, once they are obtained from follicles in different stages of development. Since this heterogeneity impacts the results of IVP, it is necessary that the processes of oocyte selection and in vitro maturation are adequate and articulated, so that occurs development of oocyte competence for subsequent development. The objective of this study was to evaluate the oocyte population obtained from large antral follicles, testing the hypothesis that healthy dominant follicles would contain oocytes with an intermediate degree of chromatin compaction (GV2 oocytes). Then we evaluated the population of oocytes obtained at random day of the estrous cycle after OPU and tested the synchronization protocol combining follicle aspiration and FSH treatment to homogenize the population and control the quality of oocytes. The results suggest that healthy dominant follicles are predominantly composed of oocytes with intermediate levels of chromatin compaction and that follicle aspiration synchronization protocols combined with FSH treatment may be useful to control oocyte quality for OPU / IVP.<br>Mestre

Avant de devenir sensibles a un stimulant de germination, les graines de striga hermonthica doivent subir un preconditionnement dans des conditions externes precises, caracterisees notamment par un faible besoin en oxygene. La cinetique d'apparition de la sensibilite aux stimulants au cours du preconditionnement a ete etudiee. Selon la nature du stimulant de germination utilise, la sensibilite apparait entre le 2eme et le 5eme jour de preconditionnement et devient maximale entre le 8eme et le 10eme jour. Cette cinetique etant connue, les modifications physiologiques et metaboliques qui pourraient etre en rapport avec l'acquisition de la sensibilite ont ete recherchees. Ces modifications ne correspondent pas a l'activation d'une voie particuliere du metabolisme respiratoire. En effet, ce dernier, qui est caracterise par une respiration mitochondriale de faible intensite et une respiration residuelle importante, evolue peu au cours du preconditionnement. La respiration residuelle pourrait, en partie, correspondre a l'utilisation des lipides comme substrats respiratoires. D'autre part, l'apparition de la sensibilite aux stimulants est correlee avec la synthese de novo d'un certain nombre de polypeptides. La germination des graines preconditionnees, qui se produit en reponse a la perception d'un signal moleculaire provenant des exsudats racinaires de l'hote, peut egalement etre induite par certaines molecules xenobiotiques. L'action de ces differents stimulants s'exerce par l'intermediaire d'une synthese d'ethylene. Le role determinant de cette hormone dans le declenchement de la germination a ete demontre par l'utilisation des inhibiteurs de la synthese ou de l'action de l'ethylene et a l'aide de substances inhibant la transduction du signal hormonal. Enfin, l'addition des stimulants entraine une stimulation intense et immediate de l'activite respiratoire et tout specialement de la voie cytochromique.

Made available in DSpace on 2015-01-26T13:21:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-15Bitstream added on 2015-01-26T13:30:59Z : No. of bitstreams: 1 000801896.pdf: 559676 bytes, checksum: dd33b174171860866d07ca337b8de314 (MD5)<br>O desenvolvimento das cordas-de-viola, na cultura da cana-de-açúcar, ocorre na fase de maior crescimento dos canaviais. Após essa fase, inicia-se o processo de estabilização de seu crescimento e de maturação. Durante esse processo, as plantas de corda-de-viola apresentam vários fluxos de florescimento que normalmente, coincidem com a época de aplicação dos maturadores na cana-de-açúcar. Desta forma, espera-se que a aplicação de maturadores na fase reprodutiva destas plantas poderá reduzir a produção de frutos e sementes, por induzir o aborto floral e/ou ainda reduzir a viabilidade das sementes produzidas. Objetivo do trabalho foi avaliar o efeito de maturadores utilizados na cultura da cana-de-açúcar sobre a germinação de sementes, o desenvolvimento das plântulas e a abscisão de estruturas reprodutivas de Ipomoea hederifolia. O experimento foi conduzido no Departamento de Biologia Aplicado a Agropecuária, UNESP/Jaboticabal, SP, Brasil. Os tratamentos experimentais constituíram-se pela aplicação de cinco maturadores: ethyl-trinexapac, glyphosate, fluazifop-p-butyl, sulfometuron-metil, ethephon e uma testemunha sobre a espécie I.hederifolia, assim que a planta atingiu os estádios desejados. Após aplicação dos maturadores foram realizadas observações do numero de estruturas reprodutivas que sofreram abscisão determinando-se a porcentagem de abscisão das estruturas reprodutivas. Quando as sementes atingiram a maturidade de colheita foram coletadas e colocadas para germinar em placas de Petri determinando-se a porcentagem de sementes germinadas, o índice de velocidade de germinação e tempo médio de germinação. Em seguida mediu-se o crescimento inicial e, posteriormente massa seca. A aplicação de ethyl-trinexapac, glyphosate e fluazifop-p-butyl quando as plantas estavam com as flores abertas reduziu a viabilidade das sementes. O tratamento com glyphosate ...<br>The morning-glory development on sugarcane crop occurs in the phase of higher growth of sugarcane. After this stage, the sugarcane stops increasing its biomass and begins the maturation stage. During this stage, the morning-glory plants are in different development stages and it usually coincide with the time of ripeners application on sugarcane.The main of this research was to evaluate the effect of ripeners used in sugarcane crop on the seeds germination, seedling development and abscission of the reproductive structures of Ipomoea hederifolia. The experiment was carried out in UNESP/FCAV- Jaboticabal, SP, Brazil. It was apllied five ripeners (ethyl-trinexapac, glyphosate, fluazifop-p-butyl, sulfometuron-metil and ethephon) and one control (without ripeners) during the reproductive period of I.hederifolia. After ripeners application, were counted abscised reproductive structures to determine the percentage of abscission of reproductive structures. The seeds of each phonological stage were collected when it reached the point of physiological maturity and it was disposed to germinate in Petri dishes to evaluate the seed germination, germination time, germination rate, initial growth and dry mass weight. Ethyl-trinexapac, glyphosate e fluazifop-p-butyl application when plants are with open flowers can reduce seed viability. Glyphosate showed the smallest length value and it can affect seedling growth. Glyphosate and ethephon caused the highest percentages of abscission of I. hederifolia reproductive structures and, it can contribute to reducing the seeds inflow to the soils

Orientador: Pedro Luis da Costa Aguiar Alves<br>Coorientador: Mariluce Pascoaina Nepomuceno<br>Coorientador: Silvano Bianco<br>Banca: Marcos Antonio Kuva<br>Banca: Rogerio Falleiros Carvalho<br>Resumo: O desenvolvimento das cordas-de-viola, na cultura da cana-de-açúcar, ocorre na fase de maior crescimento dos canaviais. Após essa fase, inicia-se o processo de estabilização de seu crescimento e de maturação. Durante esse processo, as plantas de corda-de-viola apresentam vários fluxos de florescimento que normalmente, coincidem com a época de aplicação dos maturadores na cana-de-açúcar. Desta forma, espera-se que a aplicação de maturadores na fase reprodutiva destas plantas poderá reduzir a produção de frutos e sementes, por induzir o aborto floral e/ou ainda reduzir a viabilidade das sementes produzidas. Objetivo do trabalho foi avaliar o efeito de maturadores utilizados na cultura da cana-de-açúcar sobre a germinação de sementes, o desenvolvimento das plântulas e a abscisão de estruturas reprodutivas de Ipomoea hederifolia. O experimento foi conduzido no Departamento de Biologia Aplicado a Agropecuária, UNESP/Jaboticabal, SP, Brasil. Os tratamentos experimentais constituíram-se pela aplicação de cinco maturadores: ethyl-trinexapac, glyphosate, fluazifop-p-butyl, sulfometuron-metil, ethephon e uma testemunha sobre a espécie I.hederifolia, assim que a planta atingiu os estádios desejados. Após aplicação dos maturadores foram realizadas observações do numero de estruturas reprodutivas que sofreram abscisão determinando-se a porcentagem de abscisão das estruturas reprodutivas. Quando as sementes atingiram a maturidade de colheita foram coletadas e colocadas para germinar em placas de Petri determinando-se a porcentagem de sementes germinadas, o índice de velocidade de germinação e tempo médio de germinação. Em seguida mediu-se o crescimento inicial e, posteriormente massa seca. A aplicação de ethyl-trinexapac, glyphosate e fluazifop-p-butyl quando as plantas estavam com as flores abertas reduziu a viabilidade das sementes. O tratamento com glyphosate ...<br>Abstract: The morning-glory development on sugarcane crop occurs in the phase of higher growth of sugarcane. After this stage, the sugarcane stops increasing its biomass and begins the maturation stage. During this stage, the morning-glory plants are in different development stages and it usually coincide with the time of ripeners application on sugarcane.The main of this research was to evaluate the effect of ripeners used in sugarcane crop on the seeds germination, seedling development and abscission of the reproductive structures of Ipomoea hederifolia. The experiment was carried out in UNESP/FCAV- Jaboticabal, SP, Brazil. It was apllied five ripeners (ethyl-trinexapac, glyphosate, fluazifop-p-butyl, sulfometuron-metil and ethephon) and one control (without ripeners) during the reproductive period of I.hederifolia. After ripeners application, were counted abscised reproductive structures to determine the percentage of abscission of reproductive structures. The seeds of each phonological stage were collected when it reached the point of physiological maturity and it was disposed to germinate in Petri dishes to evaluate the seed germination, germination time, germination rate, initial growth and dry mass weight. Ethyl-trinexapac, glyphosate e fluazifop-p-butyl application when plants are with open flowers can reduce seed viability. Glyphosate showed the smallest length value and it can affect seedling growth. Glyphosate and ethephon caused the highest percentages of abscission of I. hederifolia reproductive structures and, it can contribute to reducing the seeds inflow to the soils<br>Mestre

Made available in DSpace on 2017-05-12T14:48:37Z (GMT). No. of bitstreams: 1 Jaqueline.pdf: 439172 bytes, checksum: b3b777c73355c6582930e893b870b9af (MD5) Previous issue date: 2012-04-04<br>In a scenario where there is increasing production of soybeans, the quality of the storaging process is a factor of increasing concern, which requires the incorporation of technologies and production systems research in seed companies, adopting measures to ensure the viability of the seed during storage. This study aimed to evaluate the quality of seeds of five soybean cultivars recommended for the Western region of Paraná state, in the South of Brazil, after harvesting and during eight months of storage at different conditions (condition of warehouse, and cold 20 °C ± 2) to determine the effects of storage conditions on the seed, vigor loss and the most resistant cultivars. Evaluations were performed at time 0 (harvest), after the seeds were packaged in multiwall paper. Other evaluations were at 0, 60, 120, 180 and 240 days of storage, through the following tests: germination test in the laboratory, cold test, controlled deterioration, accelerated aging and tetrazolium test. The design was completely randomized factorial (5 x 2), five cultivars and two storage conditions, and results were compared statistically by Tukey test at 5% significance level. The results showed that the CD 202 cultivar had the worst performance from the beginning to the end of storage, being less resistant. The cultivar NK 412 113 was affected drastically in the accelerated aging test after 120 days of storage under both conditions. The cultivars maintained their germination in both environment and cold storage conditions until the end of the cold tests and controlled deterioration. Cultivars CD 233RR and CD 215 were the most vigorous until the end of the storaging process, in the cold chamber and starting at 120 days of storage, the vigor of cultivars CD 202, NK 412113 and NK 7059RR decreased, when subjected to accelerated aging test, indicating lower storage potential. Considering that the germination test is valid for six months, it is concluded that all cultivars showed good performance after two months of shelf life, except the CD 202 cultivar, considering the storage time studied, eight months, it can stated that the cooling storage preserved in better conditions the cultivars CD 215 and CD 233RR until the end of the period and there is no difference in vigor of seeds in terms of being conventional or transgenic.<br>Num cenário com crescente produção de sementes de soja, a qualidade da armazenagem é fator também de preocupação crescente, o que requer incorporação de tecnologias ao sistema de produção e pesquisa nas empresas sementeiras, adotando medidas que garantam a viabilidade da semente durante o armazenamento. Neste contexto, o presente trabalho teve como objetivo avaliar a qualidade de sementes de cinco cultivares de soja recomendadas para a região Oeste do Paraná, após a colheita e durante oito meses de armazenamento sob condição de armazém e de resfriamento a 20°C ± 2 para verificar seu efeito sobre a qualidade das sementes, perda de vigor e quais as cultivares que apresentam maior potencial de armazenamento. As avaliações foram realizadas no tempo 0 (colheita) e após, as sementes foram acondicionadas em embalagem de papel multifoliado. As demais avaliações ocorreram aos 60, 120, 180 e 240 dias de armazenamento, por meio dos seguintes testes: germinação, frio, deterioração controlada, envelhecimento acelerado e tetrazólio. O delineamento foi inteiramente casualizado em esquema fatorial 5 x 2, com cinco cultivares e duas condições de armazenagem. As médias foram comparadas estatisticamente pelo teste de Tukey a 5% de probabilidade. A cultivar CD 202 apresentou o pior desempenho do início ao fim do armazenamento. A cultivar NK 412113 foi afetada pelo teste de envelhecimento acelerado após 120 dias de armazenamento nas duas condições. As cultivares CD 215, NK 412113, CD 233RR e NK 7059RR mantiveram seu vigor tanto na condição ambiente quanto sob resfriamento até o final do armazenamento nos testes de frio e deterioração controlada. As cultivares CD 215 e CD 233RR foram as mais vigorosas, mantendo boa qualidade até o final do armazenamento sob resfriamento; a partir dos 120 dias de armazenamento houve decréscimo do vigor das cultivares CD 202, NK 412113 e NK 7059RR quando submetidas ao teste de envelhecimento acelerado, indicando menor potencial de armazenamento. Levando em conta que o teste de germinação tem validade por seis meses, conclui-se que todas as cultivares apresentaram bom desempenho após dois meses do prazo de validade, exceto a cultivar CD 202. Considerando o tempo de armazenamento estudado, de oito meses, pode-se afirmar que o resfriamento manteve o vigor das cultivares CD 215 e CD 233RR até o final do período. Sementes de soja armazenadas em diferentes condições apresentam comportamento distinto quanto ao vigor após 120 dias de armazenamento e não há diferença no vigor das sementes em relação à convencional ou à transgênica.

Os objetivos deste trabalho foram detectar e identificar os fungos presentes em amostras de sementes de ipê-amarelo (Tabebuia serratifolia), ipê-roxo (Tabebuia impetiginosa), aroeira-pimenteira (Schinus terebinthifolius) e aroeira-salsa (Schinus molle), coletadas em diferentes localidades (Piracicaba-SP, Mogi-Guaçu-SP, Rio das Pedras-SP, Ijaci-MG, Itumirim-MG e Lavras-MG) uma parte das amostras foram submetidas à assepsia e a outra não; verificar o efeito desses fungos na germinação dessas sementes; avaliar a transmissão de fungos das sementes para as plântulas; avaliar a patogenicidade de Pestalotiopsis sp. em mudas de aroeira-pimenteira e comparar o efeito de diferentes fungicidas (captam, carbendazim+tiram e carboxim+tiram) na incidência dos fungos e na germinação. Constatou-se que os fungos mais frequentes e em maior incidência encontrados associados às sementes, tanto de ipê-amarelo quanto de ipê-roxo, foram Cladosporium sp., Alternaria alternata, Epicoccum sp., Phoma sp., Geotrichum sp., Penicillium sp., Trichothecium sp., Phomopsis sp., Drechslera sp., Aspergillus spp., Curvularia sp. e Fusarium spp. De maneira geral, a assepsia proporcionou uma redução drástica de todos os fungos, em ambas espécies. Não houve diferença significativa na porcentagem de plântulas normais, entre as amostras, porém o tratamento com hipoclorito de sódio, reduziu a germinação em 64%. Na transmissão observou-se, em média, 17% e 10% de plântulas com sintomas, nas amostras sem assepsia e com assepsia, respectivamente. Os fungos mais freqüentes transmitidos pelas sementes de ipê foram: Alternaria alternata., Fusarium spp., Aspergillus spp., Phoma sp. e Phomopsis sp. Em relação às espécies de aroeira, os fungos quantificados foram Cladosporium sp., Alternaria alternata, Aspergillus spp., Pestalotiopsis sp., Penicillium sp., Fusarium spp., Epicoccum sp., Nigrospora sp., Curvularia sp., Drechslera sp., Trichoderma sp., Myrothecium sp. e Phoma sp. A assepsia reduziu ou manteve a incidência dos fungos, exceto para Pestalotiopsis sp. e Aspergillus spp. que aumentaram em algumas amostras de sementes de aroeira-pimenteira. Não houve diferença estatística da germinação das com e sem assepsia e entre amostras; para aroeira-salsa não verificou-se germinação. Foi confirmada a transmissão, principalmente dos fungos Cladosporium sp., Aspergillus spp. e Pestalotiopsis sp. Em mudas de aroeira-pimenteira verificou-se a patogenicidade de Pestalotiopsis sp. No tratamento de sementes com fungicidas, todos, de uma maneira geral, mostram resultados satisfatórios no controle de todos os fungos detectados, tanto para ipê quanto para aroeira. Captam apresentou resultado satisfatório principalmente em sementes de ipê, onde não foi verificado efeito fitotóxico em relação aos demais fungicidas comparados. Porém, o uso de copolímero de poliéter e silicone, um espalhante adesivo utilizado para facilitar a distribuição do produto, interferiu de forma negativa nos resultados de germinação de sementes de ipê; para aroeira não foi verificado este efeito. Torna-se necessário comparar diferentes doses e produtos para não só controlar fungos associados às sementes mas evitar problemas durante a germinação das mesmas e garantir a produção de mudas sadias e vigorosas em viveiros.<br>The objectives of this work were to detect and to identify the fungi present in samples of native forest seeds of ipê-amarelo (Tabebuia serratifolia), ipê-roxo (Tabebuia impetiginosa), aroeira-pimenteira (Schinus terebinthifolius) and aroeira-salsa (Schinus molle), collected at different places (Piracicaba-SP, Mogí-Guaçu-SP, Rio das Pedras-SP, Ijaci-MG, Itunirim-MG and Lavras-MG), submiting some parts of the asepsis and the other no; to verify the effect of these fungi in the germination of these seeds; to evaluate the transmission of seed fungi associated to seedlings; to evaluate the patogenicity of Pestalotiopsis sp. in aroeira-pimenteira seedlings and to compare the effect of different fungicides (captan, carbendaxim+tiram and carboxim+tiram) in the fungi incidence and germination. The results showed that the most incident and frequent fungi found associated to the seeds of ipê-amarelo and ipê-roxo were Cladosporium sp., Alternaria alternata, Epicoccum sp., Phoma sp., Geotrichum sp., Penicillium sp., Trichothecium sp., Phomopsis sp., Drechslera sp., Aspergillus spp., Curvularia sp. and Fusarium spp. In general, the asepsis provided a drastic reduction of all fungi, in both species. There was no significantive difference in the normal seedling percentage, independent of the sample, however the treatment with sodium hipoclorite, in the asepsis, reduced the germination in 64%. In the transmission was observed, on average, 17% and 10% of seedlings with symptoms, in the samples without asepsis and with asepsis, respectively. The most frequent fungi transmitted by ipê seeds were: Alternaria alternata., Fusarium spp., Aspergillus spp., Phoma sp. e Phomopsis sp.. In relation to aroeira species, the quantified fungi were: Cladosporium sp., Alternaria alternata, Aspergillus spp., Pestalotiopsis sp., Penicillium sp., Fusarium spp., Epicoccum sp., Nigrospora sp., Curvularia sp., Drechslera sp., Trichoderma sp., Myrothecium sp. e Phoma sp.. The The asepsis reduced or maintained the fungi incidence, except for Pestalotiopsis sp. and Aspergillus spp. That increased in some aroeira-pimenteira seeds. The germination results showed that there was no statistical difference in relation to seeds with and without asepsis and among samples. The transmission was confirmed, mainly of the fungi Cladosporium sp., Aspergillus spp. e Pestalotiopsis sp.. In aroeira-pimenteira seedlings the patogenicity of Pestalotiospsis sp. was verified. In the seeds treatment with fungicides, all, in a general way, showed satisfactory results in the control of all detected fungi, as much for ipê as for aroeira. Captan presented satisfactory result principally in ipê seeds, where fitotoxic effect had not been verified in relation to the other compared fungicides. However, the use of copolímero of polyeter and silicon, an adhesive dispersed, used to facilitate the product distribution, negatively interfered on the germination results; for aroeira this effect had not been verified in the germination. To compare different doses, products not only to control fungi associated to the seeds but to avoid problems during the germination of the same ones and to guarantee the production of healthy seedlings and vigorous in nurseries becomes necessary.

Em áreas onde o herbicida glyphosate é utilizado freqüentemente, populações da planta daninha trapoeraba (Commelina benghalensis L.) têm sido selecionadas, devido à tolerância da espécie à ação deste herbicida. Neste sentido, há necessidade de utilização de alternativas de manejo, as quais, por sua vez, são dependentes de conhecimentos profundos sobre a biologia da espécie; e também do controle químico eficiente em condições de pós-emergência, cuja eficácia depende, sobretudo, do estádio de desenvolvimento da planta daninha no momento da aplicação. Desta forma, este trabalho foi desenvolvido com o objetivo de avaliar: a germinação e a emergência das plântulas de sementes aéreas pequenas de trapoeraba (Commelina benghalensis L.) quando submetidas a diferentes temperaturas, condições de luz, superação de dormência e profundidade de semeadura; a competitividade com a cultura da soja; e avaliar a resposta biológica da C. benghalensis e da B. plantaginea a aplicações de diferentes doses do herbicida glyphosate em seis estádios fenológicos, ajustando-as aos modelos tradicionais e a funções de duas variáveis. Com relação à germinação, avaliouse o efeito da luz, temperatura, escarificação química e profundidade de semeadura no substrato. A temperatura ótima para germinação da trapoeraba foi de 25°C. Não houve efeito da luz na germinação das sementes. Não houve interferência positiva na germinação por conseqüência do tratamento das sementes com ácido sulfúrico, em diferentes períodos de exposição, indicando que o lote de sementes de trapoeraba testado não possuía impermeabilidade do tegumento à água. A emergência das plântulas de trapoeraba é influenciada negativamente e de forma linear, pela profundidade de semeadura dos propágulos no substrato. Não houve emergência das plântulas quando as sementes foram depositadas a 80 mm de profundidade. O substrato areia favorece a emergência das plântulas. Com relação à competitividade, a habilidade competitiva da trapoeraba foi semelhante à das plantas de soja, com evidências que a competição intraespecífica teve maior importância para as espécies que a competição interespecífica. Com relação ao controle químico com glyphosate, observou-se que o desenvolvimento das plantas de trapoeraba comprometeu o controle, ou seja, melhores controles foram obtidos com a aplicação de glyphosate sobre plantas jovens. Quando em análise conjunta, a trapoeraba foi mais tolerante ao herbicida que o capim-marmelada. Houve ajuste dos dados a modelos tridimensionais, correlacionando estádio fenológico, dose e controle, contudo novas estimativas devem ser realizadas, sobretudo com a inclusão de doses mais elevadas de glyphosate<br>In areas where the herbicide glyphosate is used frequently, populations of the weed Bengal dayflower (Commelina benghalensis) have been selected, due to the species tolerance to the action of that herbicide. This way, the use of alternative management is necessary, which are dependent upon deep knowledge on species biology; as well as, the efficient chemical control in post emergence conditions, which efficacy depends on the growth development stage of the weed at the moment of herbicide application. Therefore, this work was carried out with the objective of evaluating: the germination and emergency of small aerial seeds of Bengal dayflower (Commelina benghalensis L.) when exposed to different temperatures, light conditions, dormancy overcoming and seeding depth; the competitive ability with the soybean crop; to evaluate the biological rates of the C. benghalensis and the B. plantaginea the applications of different rates of the herbicide glyphosate in six phenologic stages, adjusting them the traditional models and the functions of two variable. Related to germination, light, temperature, chemical scarification and depth of seeding effects were evaluated. The optimal temperature for Bengal dayflower germination was 25°C. Light effects were not observed on seed germination. Positive consequences of seed treatment with sulfuric acid were not identified, considering different periods of exposition; that indicates that the portion of Bengal dayflower seeds tested did not have tegument water impermeability. Seedling emergence is negative and linearly influenced by seeding depth in the substrate. Seedling emergence was not figured out when seeds were 80 mm depth placed. Sand substrate favored seedling emergence. Related to competitiveness, Bengal dayflower competitive ability revealed similar to soybean plants, with evidences that intraspecific competition was more important for species than interespecific competition. Studying chemical control with glyphosate, it was observed that the development of Bengal dayflower plants compromised the control, i.e., better results were obtained with glyphosate applications on young plants. When in joint analysis, Bengal dayflower was more tolerant than alexandergrass to the herbicide. Data were adjusted to tridimensional models, correlating phenologic stage, rate and control, although new estimative must be achieved, mainly including higher doses of glyphosate.

A área de produção da cana-de-açúcar colhida mecanicamente sem a queima da palhada tem crescido consideravelmente nas últimas décadas, causando algumas alterações, selecionado algumas espécies de plantas daninhas por emergirem com facilidade sob a palha. Porém poucos estudos científicos têm sido conduzindo para elucidar este incremento na incidência. Assim sendo, esta pesquisa foi conduzida com o objetivo de avaliar: emergência de Merremia cissoides (Lam.)Hall. f., Neonotonia wightii (Am.) Lackey e Stizolobium aterrimum Piper & Tracy sob diferentes quantidades de palha e alocação das sementes em relação à camada de palha de cana-de-açúcar (profundidade); crescimento inicial das três espécies; e suceptibilidade diferencial aos herbicidas amicarbazone, imazapic e sulfentrazone. Os experimentos de emergência e de crescimento inicial foram desenvolvidos em casa-de-vegetação do Departamento de Produção Vegetal da Escola Superior de Agricultura Luiz de Queiroz, Piracicaba-SP. O trabalho de suceptibilidade a herbicidas foi desenvolvido em área pertencente à Usina São Martinho S/A, no município de Iracemápolis SP, com os herbicidas amicarbazone, imazapic e sulfentrazone, por meio de curvas de dose-resposta, onde foram aplicadas oito doses de cada herbicida, em pré-emergência. As doses utilizadas foram: 8D, 4D, 2D, D, 1/2D, 1/4D, 1/8D e testemunha sem aplicação; sendo D a dose recomendada de amicarbazone (1.200 g ha-1), ou de imazapic (147 g ha-1), ou de sulfentrazone (800 g ha-1). A emergência das plântulas foi verificada semanalmente até 21 dias após a semeadura (DAS). Ocorrendo maior emergência das espécies Merremia cissoides e Neonotonia wightii nas parcelas sem a camada de palha, e em menores profundidades de alocação das sementes no solo (35,4 e 49 %), demonstrando que apesar de serem plantas daninhas de alta incidência nas áreas de cana colhida sem queima prévia da palha, possuem sua emergência afetada pelas condições de palha e profundidade da semente no solo. Para a espécie S. aterrimum, não houve efeito de nenhum dos tratamentos, indicando ser uma planta altamente adaptada para as condições de colheita mecanizada e profundidade de alocação das sementes (87,5%). Para o ensaio de crescimento, foi observada a elevada capacidade que a planta daninha S. aterrimum possui em produzir fitomassa (25 g planta-1). A variável área foliar (Af) acompanhou o ganho de massa pela parte aérea, para as três espécies estudadas, contudo, próximo do final do experimento, apresentou estabilização da massa seca da parte aérea (Ma), sendo que S. aterrimum apresentou maior taxa de crescimento inicial e acúmulo de massas seca total, além do maior acúmulo de área foliar (Af). A espécie N. wightii apresentou crescimento inicial lento quando comparada com as outras espécies estudadas. Os níveis de controle indicaram que os herbicidas amicarbazone, sulfentrazone e imazapic controlaram as espécies M. cissoides e N. wightii (379, 814 e 152 g ha-1) para C80, porém na espécie S. aterrimum, somente o herbicida amicarbazone controlou adequadamente (1681 g ha-1), portanto foi à espécie de maior dificuldade de controle, dentre as espécies estudadas neste trabalho.<br>The production area of sugar cane for the mechanical harvest of raw cane has grown in recent decades, causing some changes, predominating some species in the culture system of raw cane because they can easily emerge under the straw. But few scientific studies have been conducted to elucidate the increased incidence. Therefore, this study was conducted to evaluate the germination and emergence of Merremia cissoides, Neonotonia wightii and Stizolobium aterrimum under different amounts of straw and seed placement in respect to the layer of sugar cane strow; evaluate the initial growth three species and their differential susceptibility to amicarbazone, imazapic and sulfentrazone. The experiments of emergency and early growth were developed in a green house of Plant Production Department, Agriculture School \"Luiz de Queiroz\", Piracicaba-SP. The work of susceptibility was developed in an area owned by Usina São Martinho SA, in Iracemápolis Brazil, with herbicides amicarbazone, imazapic and sulfentrazone, by dose-response curves, where were applied eight doses of each herbicide, in pre-emergency. The doses used were: 8D, 4D, 2D, D, 1/2D, 1/4D, 1/8D and untreated control, where D is the recommended dose of amicarbazone (1200 g ha- 1), or imazapic (147 g ha-1), or sulfentrazone (800 g ha-1). Seedling emergence was checked weekly until 21 days after sowing (DAS). Major emergency occurring species Merremia cissoids and Neonotonia wightii in the plots without the layer of straw, and at lower depths of allocation of seeds in the soil (35.4 and 49%), showing that despite being problematic weeds in fields of cane, emergency its is by affected conditions of straw and seed depth in soil. For the specie S. aterrimum, their has being no effect of any treatment, indicating be a plan to highly adapted to the conditions of harvest and allocation of seed depth (87.5 %). For the growth test, it was observed that the accumulation of dry mass, demonstrates the high capacity of this weed S. aterrimum has in producing biomass (25 g plant-1). The leaf area (Af) followed the mass gain by the shoot, for the three species studied, however, near the end of the experiment, it was observed the stabilization of the dry mass of shoots (Ma). And S. aterrimum showed higher initial growth rate and total biomass accumulation, besides the greater accumulation of leaf area (Af). And the species N. wightii proved to be a kind of as slow initial growth compared with other species. Control levels of the third experIment indicated that the herbicides amicarbazone, sulfentrazone and imazapic controlled the species M. cissoides and N. wightii (379, 814 and 152 g ha-1), but the species S. aterrimum, only the herbicide amicarbazone managed properly (1681 g ha-1). Where the species S. aterrimum proved that it is the most difficult species to control, among the species studied in this work.

Made available in DSpace on 2014-08-20T13:44:30Z (GMT). No. of bitstreams: 1 dissertacao_fernando_rodrigo_xavier.pdf: 4002704 bytes, checksum: 1d4210b27bba576305263a041837bf2a (MD5) Previous issue date: 2011-10-27<br>The use of insecticide seed treatment for soybeans is a major component in pest control at the initial stage of soybeans, as they prevent the decrease plant stand. This treatment provides it with greater security and helps ensure the productivity of the crop, besides having a much lower environmental impact compared insecticide applications by air. With the large scale soy production in Brazil and abroad, some pests that are not the culture in question may start seeing it as a new source of livelihood. The main objective of this study was to evaluate the germination, seedling size and abnormal seedlings in treatments with insecticides Semevin (thiodicarb) Hurracan (Fipronil), Imitra (Imidacloprid) and Acetra (Acephate), the dosages recommended by manufacturers. Evaluations of physiological seed quality were conducted by means of germination, seedling size and abnormal seedlings in sand substrate, with the CD 202 variety of high germination and vigor. To avoid any discrepancies between the treatments all tests were used Firewalk fungicide (Thiram + Carbendazin). Treatment with insecticide Hurracan (Fipronil) proved to be superior to other insecticides because of its proximity to the witnesses and the significant difference by Tukey 5% of the other tests, indicating a better physiological quality compared to others.<br>O uso de inseticidas no tratamento de sementes de soja é um dos principais componentes no controle de pragas na fase inicial da soja, pois evitam que estas diminuem o estande de plantas. Este tratamento propicia com isso uma maior segurança e ajuda a garantir a produtividade da lavoura, além de ter um impacto ambiental muito menor se comparado as aplicações de inseticidas por via aérea. Com a larga escala na produção de soja no Brasil e no mundo, algumas pragas que são secundarias poderão começar a promover dano economico. O objetivo principal deste trabalho foi o de avaliar a germinação, tamanho de plântulas e plântulas anormais nos tratamentos com os inseticidas Semevin (Thiodicarb), Hurracan (Fipronil), Imitra (Imidacloprid) e Acetra (Acephato), nas dosagens recomendadas pelos fabricantes. As avaliações de qualidade fisiológica das sementes foram realizadas por meio de teste de germinação, tamanho de plântulas e plântulas anormais em substrato de areia, com a variedade CD 202 de alta germinação e vigor. Para evitar alguma discrepância entre os tratamentos todos os testes foram utilizados o fungicida Firewalk (Thiram + Carbendazin). O tratamento com o inseticida Hurracan (Fipronil) mostrou-se superior aos demais inseticidas devido a proximidade com as testemunhas e a diferença significativas pelo teste Tukey 5% dos demais testes, mostrando uma melhor qualidade fisiológica se comparado aos demais.

A degradação de pastagem é um dos maiores problemas da pecuária bovina do país. A implantação seguida de um sistema de manejo inadequado favorece a ocorrência de plantas daninhas em altas densidades, o que diminui a produtividade da gramínea forrageira. A espécie Tecoma stans, importante planta daninha em pastagens, é considerada de difícil controle, pois apresenta rebrota rápida e vigorosa após o corte do tronco, dificultando seu controle por métodos exclusivamente mecânicos. Visando encontrar alternativas de controle químico e conhecer a forma como fatores ambientais influenciam a germinação e emergência da espécie, analisou-se a influência da luz e temperatura sobre a germinação e o efeito da profundidade de semeadura na emergência de T. stans. Além disso, foram estudadas a absorção, a translocação e a eficácia do herbicida aminocyclopyrachlor. Para análise do efeito da luz, sementes foram distribuídas em caixas de plástico transparente e preto, e mantidas em germinador em temperatura constante e alternada. O efeito da temperatura foi avaliado em nove intervalos de temperatura, entre 15°C e 40°C. Para o estudo da influência da profundidade de semeadura na emergência de plântulas, as sementes foram depositadas a 0, 20, 40 e 80 mm de profundidade. A absorção e translocação de 14C-aminocyclopyrachlor foram estudadas ao longo do tempo em plantas jovens de T. stans e os experimentos no campo foram conduzidos com aplicações no toco de aminocyclopyrachlor e picloram e aplicações foliares da associação formulada dos herbicidas aminocyclopyrachlor + metsulfuron-methyl e glyphosate. Os estudos do efeito da luz e temperatura demonstraram que a espécie é fotoblástica neutra e que as temperaturas estudadas não são fatores limitantes para a germinação de espécie, apresentando porcentagem de germinação acima de 50%. A espécie apresentou maior porcentagem de emergência quando as sementes foram depositadas na superfície do solo e não ocorreu emergência das plântulas quando foram depositadas nas profundidades de 40 e 80 mm. Aproximadamente 20% do total de 14Caminocyclopyrachlor aplicado foram absorvidos pelas folhas de T. stans e a porcentagem de translocação não ultrapassou 5% do total aplicado em 72 horas após a aplicação. Aplicações no toco de aminocyclopyrachlor e picloram e foliares de aminocyclopyrachlor + metsulfuron-methyl e glyphosate foram eficazes no controle de T. stans.<br>Pasture lands degradation is one of the largest problems of cattle livestock in Brazil. The development of pasture lands and its consequent inadequate management are factors that favor weed proliferation, diminishing forage grass productivity. Tecoma stans, is a difficult to control widespread weed in pasture lands since resprouts vigorously and quickly after the stalk is cut hindering its control by mechanical means. In order to find chemical alternatives to control the species and to identify the environmental factors that contribute to its germination and emergence, this study analyzed light and temperature effects on germination and seeding depth effect on the emergence of T. stans. Moreover, was analyzed the absorption, translocation and efficacy of aminocyclopyrachlor. In order to analyze the light effect, the seeds were distributed in clear and dark plastic boxes that were kept in a germination chamber in constant and alternated temperatures. The temperature effect was assessed in nine temperature intervals ranging from 15 to 40°C. In order to analyze seeding depth effect in seedlings emergence, the seeds were sowed at 0, 20, 40 and 80 mm. Absorption and translocation of 14C-aminocyclopyrachlor were analyzed over time in young T. stans plants. Field experiments were conducted applying aminocyclopyrachlor and picloram in the cut-stump and foliar applications of aminocyclopyrachlor + metsulfuron-methyl and glyphosate. Light and temperature experiments allowed to conclude that the species is neutral photoblastic and that the temperatures used in the experiments did not limit the species germination, since there were germination in 50% of the cases. When the seeds were applied in the soil surface there was a higher index of emergence, however, when the seeds were at 40 and 80 mm depth, the plant did not emerge. Twenty percent of the 14Caminocyclopyrachlor dosage applied was absorbed by T. stans leaves. Translocation percentage did not surpass 5% of the dosage applied after 72 hours. Aminocyclopyrachlor and picloram cut-stump applications as well as aminocyclopyrachlor + metsulfuron-methyl and glyphosate foliar applications were efficacy to control T. stans.

CAPES<br>A forte pressão de seleção exercida pelo uso intensivo do herbicida glyphosate em áreas cultivadas tem selecionado populações de espécies Borreria latifolia (Aubl.) K.Shum. (erva-quente), Galianthe chodatiana (Standl.) E.L. Cabral (galiante) e Richardia brasiliensis Gomes (poaia-branca), pertencentes à família Rubiaceae, com sensibilidade diferencial a este herbicida no Sul do Brasil. A dificuldade de controle com herbicidas sinaliza a necessidade de adoção de práticas de manejo da flora ruderal e de cultivos mais sustentáveis e que resultem em controle mais eficiente das populações a longo prazo. O presente estudo objetivou: (a) selecionar métodos eficazes para a superação de dormência de B. latifolia e G. chodatiana e determinar como os mesmos influenciam na cinética da germinação das sementes dessas espécies; (b) analisar o efeito de temperaturas, da irradiância, do pH, do alumínio e da salinidade no processo germinativo de sementes e no crescimento inicial de plântulas de B. latifolia, G. chodatiana e R. brasiliensis; (c) avaliar os níveis de tolerância ao glyphosate em biótipos de B. latifolia, G. chodatiana e R. brasiliensis por meio de curvas de dose-resposta utilizando dois métodos de avaliação de controle pelo herbicida; (d) e avaliar a eficiência de herbicidas alternativos no controle em pré-emergência, pós-emergência inicial e pós-emergência tardia das três espécies rubiáceas. A associação de KNO3 2%/3h + ácido giberélico 400 ppm resultou na maior porcentagem de germinação de sementes de G. chodatiana. Esse tratamento e também o de calor seco 60°C/30 min+ KNO3 2%/3h foram mais efetivos na superação da dormência de B. latifolia. G. chodatiana e R. brasiliensis toleraram temperaturas mais baixas durante o processo germinativo, enquanto B. latifolia tolerou temperaturas mais elevadas. B. latifolia e R. brasiliensis apresentaram-se fotoblásticas positivas, enquanto G. chodatiana foi indiferente ao fotoperíodo. B. latifolia apresentou germinação e desenvolvimento inicial mais elevado em pH 3, enquanto G. chodatiana e R. brasiliensis demonstraram preferencia por pH entre 5 e 7. B. latifolia e G. chodatiana foram mais tolerantes à presença do alumínio durante o processo germinativo do que R. brasiliensis. Baixos índices salinos foram suficientes para inibir boa parte da germinação das sementes das três espécies. Alguns biótipos de B. latifolia e R. brasiliensis apresentaram tolerância média a elevada ao glyphosate, não sendo controlados por doses acima da recomendada. A espécie G. chodatiana não foi controlada com a maior dose utilizada no experimento, sulfentrazone, S-metolachlor e saflufenacil apresentaram boa eficiência no manejo em pré-emergência tanto de B. latifolia quanto de R. brasiliensis, enquanto chlorimuron-ethyl e diclosulan foram eficientes somente sobre R. brasiliensis. Em apresentando elevada tolerância ao herbicida. Os herbicidas pós-emergência inicial os herbicidas fomesafen, lactofem e flumioxazin controlaram as eficientemente apenas B. latifolia. Destaca-se a suscetibilidade da espécie G. chodatiana para aplicações em pós-emergência inicial, pois estádios ontogênicos mais avançados reduzem os níveis de controle da espécie e as alternativas químicas. Diferentes tratamentos, associados ao glyphosate ou em aplicações sequenciais, foram eficazes em controlar as plantas de B. latifolia e R. brasiliensis em estádio de desenvolvimento avançado.<br>The strong selection pressure exerted by intensive use of glyphosate in cultivated areas has selected populations of the Rubiaceae weed species Borreria latifolia (Aubl.) K.Shum. (broadleaf buttonweed), Galianthe chodatiana (Standl.) E.L. Cabral (galiante) and Richardia brasiliensis Gomes (Brazilian pusley) with differential sensitivity to this herbicide in the South region of Brazil. The control of these weeds with herbicides is troublesome and signals the need to incorporate management practices of ruderal flora and crops, more sustainable and that results in more efficient control for long-term. Therefore, it is very important to expand the information about their biology and management. This study aimed: (a) select efficient methods to overcome dormancy of B. latifolia and G. chodatiana and determine how they influence the kinetics of seeds germination; (b) analyze the effects of temperature, irradiance, pH, aluminum and salinity on seed germination and initial growth of the B. latifolia, G. chodatiana e R. brasiliensis seedlings; (c) evaluate tolerance to glyphosate levels in biotypes of B. latifolia, G. chodatiana e R. brasiliensis through dose-response curves and compare two methods to evaluate herbicidal control; (d) and evaluated the effectiveness of alternative herbicides in pre-emergence and in early and late post-emergence of the three species. The treatment with KNO3 2%/3h + gibberellic acid 400 ppm resulted in higher percentage of G. chodatiana seed germination. This treatment and also the dry heat (60°C/30 min) + KNO3 2%/3h were more effective in overcoming dormancy of B. latifolia. G. chodatiana and R. brasiliensis tolerate lower temperatures during the germination process, while B. latifolia tolerate higher temperatures. B. latifolia and R. brasiliensis are positive photoblastic while G. chodatiana is indifferent to the photoperiod. B. latifolia shows higher germination and early development in pH 3, while G. chodatiana and R. brasiliensis prefer pH range between 5 and 7. B. latifolia and G. chodatiana were more tolerant to the aluminum during the germination process than R. brasiliensis. Low salt levels were sufficient to reduce the seed germination of the three species. Some biotypes of B. latifolia and R. brasiliensis showed medium-high glyphosate tolerance, not being controlled by higher doses than recommended. The G. chodatiana specie was not controlled with the highest dose used, showing a high glyphosate tolerance. The sulfentrazone, s-metolachlor and saflufenacil herbicides sprayed in pre-emergence showed high efficacy both on B. latifolia and R. brasiliensis, while chlorimuron-ethyl and diclosulan were effective only on R. brasiliensis. In early post-emergence the fomesafen, lactofem and flumioxazin herbicides efficiently controlled plants of all species, while bentazon showed high efficacy only on B. latifolia. Noteworthy the susceptibility of the G. chodatiana specie for applications in early post-emergence, because the control effectiveness and the number of effective herbicides are reduced with increasing the plant age. Many treatments with tank mix or sequencial applications with glyphosate, were effective in controlling B. latifolia and R. brasiliensis plants in advanced stage of development.

Schema reliant en fonction des saisons, les facteurs du milieu (enneigement, averses, rugosite, temperature et humidite de l'air et du sol) aux processus physiques et biotiques (protection, erosion, accumulation; microclimat ou activite des limaces) et aux stades phenologiques (graines, graines germees, semis rampants, deplaces ou implantes). On demontre l'importance du premier mois de developpement de la plantule sur sa survie apres la germination

Bambara groundnut is a protein-rich legume, with food security potential in drought-prone regions. It has been grown for many centuries and has remained an important crop to most African subsistence farmers. However, despite its high nutritional status and yield advantages in poor soils, it remains one of the neglected crops by science. There have now been recent efforts to study underutilised crops, with the aim of promoting them as healthy alternatives for people facing resource and environmental challenges and to contribute to food security. In order to do this, there needs to be information that can be used to advise farmers on the agronomic aspects of producing the crop. The overall aim of the study was to evaluate the response of bambara groundnut landraces to drought under controlled environment and field conditions. Seeds were initially collected from subsistence farmers in Jozini, KwaZulu-Natal, and characterised into three seed lots distinguished by seed coat colour: red, white and brown. In the initial study (Chapter 2) seed quality of bambara groundnuts was evaluated. Seed lots were used for standard germination (SG) and cold test (CT). Seeds were germinated under two conditions, 25°C for 8 days (SG) and 4°C for 7 days followed by 8 days at 25°C (CT). Germination percentage, seedling size and mass were determined. Desiccation tolerance was evaluated by suspending 30 seeds of each seed lot over saturated salt solutions of NaCl, LiCl, KNO3 and H2O (control) for 0, 2, 4, 8, 24 and 48 hours. Five seeds were sampled at each interval and stored at -21°C for 7 days. Samples were ground and analysed for proline content. In addition, early establishment performance of bambara groundnut was evaluated under controlled environment conditions in seedling trays using two water regimes (Chapter 2). The experimental design had three factors: seed lot (colour), priming (NaCl, LiCl, KNO3, H2O and control) and water regimes [25% and 75% Field Capacity (F.C.)]. The experiment was replicated three times. Seedling emergence was determined daily for 21 days. Seedling height and leaf number were determined weekly for three weeks, thereafter, seedling leaf area, root and shoot mass (fresh and dry), root and shoot lengths and root to shoot ratio were also determined. Seedlings were later transplanted in 90 pots for a pot trial in order to evaluate growth responses of bambara groundnut to water stress; plant height, leaf number and yield components were determined (Chapter 3). Lastly, the use of planting date selection as a management strategy for managing the occurrence of water stress under field conditions was evaluated in field trials. The experimental design was a split-split-plot design with planting date as main factor (early, optimum and late), irrigation and rainfed as sub-main factor, and seed colour as sub-plots (brown, red and white) arranged in a randomised complete block design (RCBD), with three replications. There were three planting dates: 7 September (early planting), 24 November (optimum planting) and 19 January (late planting). Results from Chapter 2 showed that the brown seed lot had the highest germination across treatments, followed by red and white seeds, respectively. There were significant differences between seed lots (P < 0.05) and salt solutions (P < 0.05) with respect to proline content. Seed proline content increased from 0 to 8 hours and later declined; NaCl was associated with the highest proline accumulation. There were highly significant differences (P < 0.001) between seed colours, priming treatments and F.C., as well as their interaction, with respect to seedling emergence. White seeds had the highest emergence, followed by brown and red, respectively. Priming seeds improved their emergence compared to the control, with highest emergence being observed in seeds treated with LiCl. Priming also improved emergence under water stress; 25% F.C. had the highest emergence compared to 75% F.C. Results from Chapter 3 showed that, seeds primed with NaCl and KNO3 resulted in tallest plants with the highest number of leaves per plant. However, NaCl and KNO3 were also the most affected under water stress. Priming was shown to improve germination and early crop establishment of bambara groundnut landraces under water stress. However, yield per plant did not improve in response to either halo- or hydro-priming. Results from field trials showed that in terms of the measured plant growth parameters (plant height, leaf number and LAI), bambara groundnut landraces were sensitive water stress. Water stress decreased yield components, and hence yield. However, selection of planting dates was shown to be a useful management tool for managing water stress under water limited field conditions. Choice of planting date significantly affected both plant growth and yield. The optimum planting date resulted in the best crop growth for all measured plant growth parameters followed by late and early planting dates, respectively. Seed quality was shown to be associated with seed lot colour. Darker coloured (red and brown) seeds performed better than light (white) seeds with respect to germination. Priming was also shown to improve germination and early crop establishment of bambara groundnut landraces under water stress. However, yield per plant did not improve following priming. Growth of bambara groundnut landraces was shown to be sensitive to water stress. Water stress decreased yield components and hence yield under both controlled and field conditions. Choice of planting date significantly affected both plant growth and yield. The optimum planting date was shown to be the best performing planting date. The findings of this study suggest that bambara groundnut seed performance in terms of germination, stand establishment and productivity is associated with seed lot colour. Seed priming improves seed performance and enhances crop capacity to withstand water stress. If the optimum planting date for groundnuts (late spring to early summer) is missed, better crop performance and yield are obtained from late planting (late summer to early spring) compared with early planting (early spring). Bambara groundnut has a potential for production under water stress conditions in controlled and field environments.<br>Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

With the loss of field burning the amount of crop residue that remains in perennial ryegrass fields has increased. As the amount of crop residue remaining in the field increases so does annual bluegrass. This has resulted in the increased use of herbicides to control annual bluegrass. However, this increased use has also resulted in herbicide-resistant annual bluegrass. Field experiments were initiated in 1997 to investigate residue management options available to growers and their impacts on annual bluegrass emergence. Two sites, Glaser and Wirth, were established with three residue management treatments replicated four times. The treatments included full-straw, bale/flail, and vacuum sweep. Perennial ryegrass seed yield and annual bluegrass seed contamination were evaluated. The vacuum sweep treatment had lower annual bluegrass emergence than the full-straw or the bale/flail treatments during the 1997-98 growing season, for both sites. The fall of 1998 was much drier than the fall of 1997. Annual bluegrass emergence in all plots was lower in 1998 than in 1997 because of the dry conditions. Fall emergence in 1998 was higher in the vacuum sweep treatment than in the other two treatments, which may have been the result of better soil-seed contact in the vacuum sweep treatment. Lower emergence in the spring at the Wirth site compared to the Glaser site may have been due to narrow crop row spacing and cultivar selection, which shaded the annual bluegrass. When growing seasons were combined, there were no treatment differences. However, more emergence was observed in the spring at the Glaser site compared to the Wirth site. Yield was highest for the vacuum sweep treatment at the Glaser site in the 1998-99 growing season. However, competition from volunteer perennial ryegrass in the full-straw and bale/flail treatments could have accounted for this increase. No other differences in yield and no difference in contamination among treatments were observed. However, contamination at the Glaser site was higher in the 1998-99 growing season than in the 1997-98 growing season. Experiments were conducted in growth chambers to determine how differing environmental conditions affect seed germination of diuron-susceptible and diuron-resistant annual bluegrass. Cumulative germination for the susceptible-biotype decreased from 96% to 88% while the resistant-biotype remained above 95% as temperature decreased from 3 0/20 C to 10/2 C. The susceptible-biotype germinated sooner than the resistant-biotype regardless of temperature. The susceptible-biotype had a higher rate of germination than the resistant-biotype at 30/20 C, but not when the temperature decreased to 10/2 C. Germination response to differing matric potentials did not vary much within a biotype for a given soil type and temperature. Therefore, parameters estimated at -1.03 MPa were chosen to contrast susceptible- and resistant biotypes, and soil types, for each temperature. Maximum cumulative germination was greater than 96% for all treatments. When germination on a given soil type was contrasted, differences were only seen for the susceptible biotype vs. resistant biotype on Dayton soil; and the resistant biotype on Dayton soil vs. resistant biotype on Woodburn soil at both temperatures. The lag in onset of germination was shorter for the susceptible biotype on Dayton soil and resistant biotype on Woodburn soil than the resistant biotype on Dayton soil at 30/20 C. At 18/5 C, the lag in onset of germination was shorter for the susceptible biotype on Dayton soil and resistant biotype on Woodburn soil than the resistant biotype on Dayton soil (P = 0.000 1 and 0.0001, respectively). But the rate of germination was faster for the resistant biotype on Dayton soil than both the susceptible biotype on Dayton soil and resistant biotype on Woodburn soil at 18/5 C (P = 0.02 and 0.0004, respectively). The rate of germination did not differ at 3 0/20 C. When just the soils were contrasted, at 18/5 C all annual bluegrass seeds on the Woodburn soil germinated sooner and the rate of germination was higher than on the Dayton soil. These results indicate that the hydraulic properties of the soils may influence germination. However, this was not observed at 30/20 C. The results suggest that the susceptible-biotype was more sensitive to temperature while the resistant-biotype was more sensitive to moisture. Changing crop management in ways that will reduce annual bluegrass emergence and establishment is needed. By altering management strategies, growers may obtain more efficient and effective use of herbicides, while reducing the selection of herbicide-resistant annual bluegrass.<br>Graduation date: 2000

Bambara groundnut (Vigna subterranea L. Verdc) is a drought tolerant African legume capable of producing reasonable yields where other crops may fail. However, it remains an underutilised crop, owing to limited research, cultivated using landraces, of which scant information is available describing their agronomy and genetic diversity. The aim of this study was to evaluate the response of bambara landraces from different geographical locations to water stress under controlled and field conditions. Seeds were sourced from subsistence farmers of Tugela Ferry and Deepdale in KwaZulu-Natal (South Africa) and Zimbabwe, and characterised into three seed coat colours: light-brown, brown and red. Seed quality was assessed using the standard germination test. Vigour indices of germination velocity index and mean germination time were determined. Seedling establishment was evaluated using seedling trays using a factorial experiment, with four factors: 1. provenance – (Tugela Ferry and Deepdale), 2. seed colour – (red, light-brown and brown), 3. water regimes – (30%, 60% and 100% field capacity), and 4. soil media – (clay, sand and clay + sand). Seedling leaf samples were used to evaluate proline accumulation as an indicator of stress tolerance. A field trial was used to evaluate productivity of bambara landraces under rainfed and irrigated conditions. A pot trial was conducted under controlled environment conditions with three factors: temperature (33/27°C and 21/15°C), water regimes (30% and 100% of crop water requirement) and bambara landrace selections. Results showed no significant differences in germination capacity between bambara landrace selections. Germination time differed significantly (P<0.001) between bambara landrace selections. The Jozini provenance was shown to perform best, followed by Zimbabwe, Tugela Ferry and Deepdale. Brown landrace selections had higher (P<0.001) germination compared with red and light-brown selections, respectively. Seedling establishment showed that emergence was higher (P<0.001) at 100% FC compared with 60% FC and 30% FC. Emergence was higher (P<0.001) in the Sand+Clay mixture compared with Clay and Sand media. Dark-coloured selections had higher (P<0.001) emergence compared with light-coloured selections. Results from the field trial showed that the red landrace selections emerged better (P<0.001) than the light-brown and brown landrace selections, respectively. Plant growth was lower under irrigated compared with rainfed conditions. Stomatal conductance was higher (P<0.001) under irrigated compared with rainfed conditions, whereas chlorophyll content index was higher (P<0.05) under rainfed compared with irrigated conditions. Results of the pot trial showed that emergence was significantly (P<0.001) affected by temperature. It was higher at 33/27°C compared with 21/15°C (P<0.001). Dark-coloured landraces had higher emergence compared with the light-brown landraces. Stomatal conductance was lower at 30% ET relative to 100% ETc. There were no significant differences between water regimes with respect to biomass, pod number per plant, pod mass per plant, seed number per pod, seed mass per plant and harvest index. It is concluded that seed colour is an important variable in the identity of bambara landraces. Provenance plays a significant role in seed performance and there is a significant interaction between provenance and seed coat colour. This study could be expanded to obtain more data for crop improvement through inclusion of many sites and seasons for better agronomic advice to farmers.<br>Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.