O capim-amargoso é uma planta daninha de difícil controle. Além de apresentar características de tolerância ao uso de herbicidas, como a presença de rizoma, e cera em sua superfície foliar, a espécie apresenta biótipos resistentes ao herbicida glyphosate. O glyphosate é o herbicida mais utilizado no mundo. Este trabalho objetivou avaliar as características foliares que contribuem para a absorção diferencial do herbicida glyphosate em biótipos resistentes de capim-amargoso. Para isso foram realizados estudos de microscopia eletrônica de luz e varredura em diferentes estádios vegetativos da planta. Em uma segunda parte, tratou-se da análise molecular de plantas resistentes, através da análise do sequenciamento e da expressão da enzima EPSPs. Foram ainda comparados diferentes biótipos quanto a sua similaridade na constituição enzimática. Por fim, analisou-se as alternativas de controle químico pelo estudo da associação de diferentes formulações de glyphosate com graminicidas. Estes trabalhos foram realizados em dois estádios vegetativos da espécie, sendo um estádio inicial e um estádio avançado (pré-florescimento). Como resultados, notou-se que as plantas suscetíveis apresentam características que facilitam a absorção do herbicida, como a presença de tricomas não cuticulados. A presença destes somada a espessa epiderme adaxial favorece a absorção no biótipo suscetível. Nos estudos enzimáticos, foram encontradas duas mutações de aminoácidos que compõe a enzima EPSPs. A expressão da enzima não foi conclusiva. O biótipo suscetível apresentou maior expressão da mesma. Esta expressão diferencial pode estar relacionada a uma maior eficiência da enzima em plantas resistentes. As plantas resistentes expressam os dois tipos de enzima, enquanto as suscetíveis apenas um. O uso de graminicidas em mistura com glyphosate é eficaz, porém o controle feito em estádios iniciais da planta é mais satisfatório. O uso de formulações de rápida absorção favorece o controle de plantas. O uso de quizalofop-ethyl foi superior aos demais graminicidas, não mostrando efeitos antagonísticos em associações com glyphosate. Recomenda-se que em estádios mais avançados das plantas, outras medidas, fora o controle químico sejam utilizadas, integradas em uma manejo integrado de plantas daninhas. / The sourgrass is a hardy-to-kill weed. Besides characteristics of tolerance to herbicides, as the presence of rhizome and wax at leaf surface, there are present glyphosate-resistant biotypes. Glyphosate is the most used herbicide in the world. This study aimed to evaluate foliar characteristics that contribute to the differential absorption of the glyphosate in resistant biotypes of sourgrass. For this study has been performed scanning electron and scanning light microscopy at different vegetative stages of the plant. In a second part, it was analyzed the molecular biology of resistant plants EPSPs, through the sequencing and expression of the enzyme. Biotypes were also compared as their similarity in enzymatic constitution. Finally, were analyzed the chemical alternatives to control resistant sourgrass by studying the association of different glyphosate formulations with grass-herbicides. These studies were conducted in two stages of development of plants, one in early stage and other in advanced stage (before flowering). It was noted that susceptible plants have characteristics that facilitate the herbicide absorption, such as trichomes without wax. The presence of these plus the thick adaxial epidermis favors the absorption susceptible biotype. In enzymatic studies, were found two amino acids mutations at EPSPS gene composition. Expression of the enzyme was not conclusive. The susceptible biotype showed higher expression of it. This differential expression may be related to the increased efficiency of the enzyme in resistant plants. The resistant plants express two kinds of enzyme, while the sensitive biotype just one. The use of glyphosate in mixture with grass herbicides was effective, but the control is better in early stages of. The use of glyphosate formulations with rapid absorption enhances the control. The use of quizalofop - ethyl is better than the others herbicides tested, showing no antagonistic effects in association with any glyphosate formulation. It is recommended that at later stages of the plants development, others measures outside the chemical control should be used in an integrated management of weeds.

O capim-amargoso é uma planta daninha de difícil controle. Além de apresentar características de tolerância ao uso de herbicidas, como a presença de rizoma, e cera em sua superfície foliar, a espécie apresenta biótipos resistentes ao herbicida glyphosate. O glyphosate é o herbicida mais utilizado no mundo. Este trabalho objetivou avaliar as características foliares que contribuem para a absorção diferencial do herbicida glyphosate em biótipos resistentes de capim-amargoso. Para isso foram realizados estudos de microscopia eletrônica de luz e varredura em diferentes estádios vegetativos da planta. Em uma segunda parte, tratou-se da análise molecular de plantas resistentes, através da análise do sequenciamento e da expressão da enzima EPSPs. Foram ainda comparados diferentes biótipos quanto a sua similaridade na constituição enzimática. Por fim, analisou-se as alternativas de controle químico pelo estudo da associação de diferentes formulações de glyphosate com graminicidas. Estes trabalhos foram realizados em dois estádios vegetativos da espécie, sendo um estádio inicial e um estádio avançado (pré-florescimento). Como resultados, notou-se que as plantas suscetíveis apresentam características que facilitam a absorção do herbicida, como a presença de tricomas não cuticulados. A presença destes somada a espessa epiderme adaxial favorece a absorção no biótipo suscetível. Nos estudos enzimáticos, foram encontradas duas mutações de aminoácidos que compõe a enzima EPSPs. A expressão da enzima não foi conclusiva. O biótipo suscetível apresentou maior expressão da mesma. Esta expressão diferencial pode estar relacionada a uma maior eficiência da enzima em plantas resistentes. As plantas resistentes expressam os dois tipos de enzima, enquanto as suscetíveis apenas um. O uso de graminicidas em mistura com glyphosate é eficaz, porém o controle feito em estádios iniciais da planta é mais satisfatório. O uso de formulações de rápida absorção favorece o controle de plantas. O uso de quizalofop-ethyl foi superior aos demais graminicidas, não mostrando efeitos antagonísticos em associações com glyphosate. Recomenda-se que em estádios mais avançados das plantas, outras medidas, fora o controle químico sejam utilizadas, integradas em uma manejo integrado de plantas daninhas. / The sourgrass is a hardy-to-kill weed. Besides characteristics of tolerance to herbicides, as the presence of rhizome and wax at leaf surface, there are present glyphosate-resistant biotypes. Glyphosate is the most used herbicide in the world. This study aimed to evaluate foliar characteristics that contribute to the differential absorption of the glyphosate in resistant biotypes of sourgrass. For this study has been performed scanning electron and scanning light microscopy at different vegetative stages of the plant. In a second part, it was analyzed the molecular biology of resistant plants EPSPs, through the sequencing and expression of the enzyme. Biotypes were also compared as their similarity in enzymatic constitution. Finally, were analyzed the chemical alternatives to control resistant sourgrass by studying the association of different glyphosate formulations with grass-herbicides. These studies were conducted in two stages of development of plants, one in early stage and other in advanced stage (before flowering). It was noted that susceptible plants have characteristics that facilitate the herbicide absorption, such as trichomes without wax. The presence of these plus the thick adaxial epidermis favors the absorption susceptible biotype. In enzymatic studies, were found two amino acids mutations at EPSPS gene composition. Expression of the enzyme was not conclusive. The susceptible biotype showed higher expression of it. This differential expression may be related to the increased efficiency of the enzyme in resistant plants. The resistant plants express two kinds of enzyme, while the sensitive biotype just one. The use of glyphosate in mixture with grass herbicides was effective, but the control is better in early stages of. The use of glyphosate formulations with rapid absorption enhances the control. The use of quizalofop - ethyl is better than the others herbicides tested, showing no antagonistic effects in association with any glyphosate formulation. It is recommended that at later stages of the plants development, others measures outside the chemical control should be used in an integrated management of weeds.

Glyphosate-resistant (GR) giant ragweed (Ambrosia trifida L.) has been confirmed in several states across the mid-western and mid-southern U.S. Greenhouse and lab studies were conducted to investigate possible mechanism of glyphosate resistance in a suspect population from Monroe County, Mississippi. Translocation of 14C-glyphosate in the susceptible biotype was 77%, compared to 12% in the resistant biotype at 120 hours after treatment, suggesting that the glyphosate resistance mechanism for this giant ragweed biotype is reduced translocation. Dose response studies were conducted to confirm and characterize glyphosate resistance in suspect biotypes from Mississippi (MS-R) and Tennessee (TN-R). The ED50 for MS-R and TN-R were 3.9- and 6.3-fold higher than a susceptible biotype. Results from a fallow field study conducted in 2016 in Monroe County revealed PRE and POST treatments containing dicamba and mesotrione alone and in various combinations provided effective control of GR giant ragweed. Studies were conducted to measure fitness, phenotypic, and genetic variation among GR biotypes from MS-R, TN-R, and Ohio (OH-R). Non-destructive measurements of plants over an eight-week period revealed rapid early growth of two GR accessions from MS in the absence of glyphosate. However, no differences in vegetative biomass were recorded after eight weeks with the exception of OH-R biotype which exhibited lower biomass due to photoperiod sensitivity. Vegetative biomass and fecundity were similar. Multivariate and PCA analysis of traits grouped biotypes based on state of origin. Groupings by state of origin can be significant as managers could design similar methods of control to address giant ragweed in these areas. Simple sequence repeat (SSR) markers were used to record genetic diversity among and within biotypes. Genetic diversity values were high at 0.514, 0.502, and 0.525 within biotypes from MS, TN, and OH, respectively. However, genetic diversity did not differ due to glyphosate response or level of glyphosate resistance. High levels of genetic variation can be an indicator of the ability of giant ragweed biotypes to adapt to changing environments and conditions.

The onion (Allium cepa L.) is the most agronomically important vegetable crop to New Zealand. In temperate climates, such as New Zealand, the most prominent problem associated with onion production is weed control. To address this problem, glyphosate-resistant onions were generated in a range of germplasm backgrounds via Agrobacterium-mediated transformation of immature embryos (Eady et al. 2003a). This thesis contains an analysis of these onions. PCR and Southern analysis were used to create molecular profiles for individual transgenic events. Of the 17 putatively transgenic onion lines tested, 16 contained a single copy of the CP4 EPSPS gene integrated into their genomes, and one line had two copies of the gene. The spectinomycin resistance gene, located on the backbone of the vectors used in the transformation process, was detected in two of the glyphosate-resistant onion lines tested. Ten different glyphosate-resistant onion lines were subjected to field trial evaluation over the 2004/2005 growing season in Canterbury. Glyphosate-resistant onion seedlings were transplanted into the field in a randomised block design and a subset of plants, chosen to represent selected lines, were sampled. Tissue was harvested from young leaves, old leaves, and bulbs. Quantitative multiplex RT-PCR was used to assess expression of the CP4 EPSPS transcript, and protein levels were determined using an ELISA-based assay. The transgene appears to be highly transcribed in some lines, as expression of the CP4 EPSPS gene was in the same order of magnitude as the highly transcribed 18S internal control. The CP4 EPSPS protein levels of the glyphosate resistant onion lines presented in this thesis ranged between 0.36–7.44 µg CP4 g-1FW in the leaf samples, which is a little lower than, but still similar to, values reported for glyphosate resistant corn and poplar. This project reports the first in-depth analysis into the expression of the CP4 EPSPS gene in field-grown glyphosate-resistant onion lines.

Waterhemp was a sporadic weed in Kentucky soybean production since the 1970’s. Waterhemp’s presence was not significant until the 1990’s after a widespread adoption of imazaquin and imazethapyr herbicides in the late 1980’s by Kentucky farmers which resulted in ALS-resistant waterhemp in some Kentucky areas. The introduction of glyphosate resistant soybeans in 1996 resulted in glyphosate-containing products being widely used by Kentucky farmers. Waterhemp populations resistant to glyphosate have occurred in Kentucky in the past few years. The majority of Kentucky soybeans are produced in some type of conservation tillage system, primarily to conserve soil and water, which is advantageous on Kentucky’s rolling topography. Glyphosate controls a wide range of weeds and popular with farmers because of this characteristic. However, waterhemp resistant to glyphosate developed in some fields with the continuous glyphosate usage. Waterhemp control research trials were conducted in Union and Hancock Counties in Western Kentucky in an attempt to find herbicide combinations to provide season-long control. Waterhemp populations in these studies were resistant and susceptible to glyphosate but the resistant populations were great enough to cause soybean yield loss if not controlled. KEYWORDS: Amaranthus tuberculatus, Herbicide Resistance, EPSPS, PPO, ALS

The onion (Allium cepa L.) is the most agronomically important vegetable crop to New Zealand. In temperate climates, such as New Zealand, the most prominent problem associated with onion production is weed control. To address this problem, glyphosate-resistant onions were generated in a range of germplasm backgrounds via Agrobacterium-mediated transformation of immature embryos (Eady et al. 2003a). This thesis contains an analysis of these onions. PCR and Southern analysis were used to create molecular profiles for individual transgenic events. Of the 17 putatively transgenic onion lines tested, 16 contained a single copy of the CP4 EPSPS gene integrated into their genomes, and one line had two copies of the gene. The spectinomycin resistance gene, located on the backbone of the vectors used in the transformation process, was detected in two of the glyphosate-resistant onion lines tested. Ten different glyphosate-resistant onion lines were subjected to field trial evaluation over the 2004/2005 growing season in Canterbury. Glyphosate-resistant onion seedlings were transplanted into the field in a randomised block design and a subset of plants, chosen to represent selected lines, were sampled. Tissue was harvested from young leaves, old leaves, and bulbs. Quantitative multiplex RT-PCR was used to assess expression of the CP4 EPSPS transcript, and protein levels were determined using an ELISA-based assay. The transgene appears to be highly transcribed in some lines, as expression of the CP4 EPSPS gene was in the same order of magnitude as the highly transcribed 18S internal control. The CP4 EPSPS protein levels of the glyphosate resistant onion lines presented in this thesis ranged between 0.36–7.44 µg CP4 g-1FW in the leaf samples, which is a little lower than, but still similar to, values reported for glyphosate resistant corn and poplar. This project reports the first in-depth analysis into the expression of the CP4 EPSPS gene in field-grown glyphosate-resistant onion lines.

Submitted by Gabrielle de Castro Macedo (gabriellecmacedo@gmail.com) on 2018-06-08T21:57:13Z No. of bitstreams: 1 Tese Gabrielle M.pdf: 2925084 bytes, checksum: df56d11b8216e24580f2f7ca847eb592 (MD5) / Approved for entry into archive by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-06-11T12:07:38Z (GMT) No. of bitstreams: 1 macedo_gc_dr_botfca.pdf: 2799637 bytes, checksum: 38a0ff40cf7c14a31feec651dd99b926 (MD5) / Made available in DSpace on 2018-06-11T12:07:39Z (GMT). No. of bitstreams: 1 macedo_gc_dr_botfca.pdf: 2799637 bytes, checksum: 38a0ff40cf7c14a31feec651dd99b926 (MD5) Previous issue date: 2018-05-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O emprego de substâncias tóxicas as plantas, como o glyphosate, em doses muito menores que as recomendadas comercialmente pode ocasionar alterações em varáveis como crescimento, acúmulo de biomassa, altura, conteúdo de proteína e resistência a doenças. Desta forma, os objetivos deste trabalho foram realizar estudos para uma melhor compreensão das alterações bioquímicas, fisiológicas e fenológicas do arroz causadas por subdoses de glyphosate. O experimento 1 foi realizado à campo, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas, FCA/UNESP, Botucatu/SP, nos anos agrícolas de 2015/2016 e 2016/2017. O delineamento experimental utilizado foi o de blocos casualizados, arranjado em esquema fatorial 2x7, sendo o primeiro fator época de aplicação do glyphosate (V3 ou R1) e, o segundo, as doses do herbicida (0; 7,5; 15; 30; 60; 120 e 240 g e.a. ha-1), com quatro repetições. Foram avaliados a produtividade, o comprimento de panículas, número de perfilhos por m², peso de 1000 grãos, número de grãos por panícula, a fertilidade de espiguetas e o número de dias entre a aplicação e o início de cada fase fenológica. Os experimentos 2 e 3 foram realizados em casa de vegetação, no Núcleo de Pesquisas Avançadas em Matologia (NUPAM), pertecentente à Faculdade de Ciências Agronômicas, FCA/UNESP, Botucatu/SP. O experimento 2 seguiu delineamento inteiramente casualizado em esquema fatorial (7x3) com cinco repetições. Os tratamentos foram constituídos por sete doses do herbicida glyphosate (0; 7,5; 15; 30; 60; 120 e 240 g e.a. ha-1) aplicados no estádio V3, e 3 períodos de chuva após a aplicação (12, 24 horas e ausência). Foram avaliados o perfilhamento e o acúmulo de massa das plantas. O experimento 3 foi arranjado em delineamento inteiramente casualizado em esquema fatorial (7x3) com quatro repetições. Os tratamentos foram constituídos por dez doses do herbicida glyphosate (0; 1,5; 3; 6; 12; 24; 36; 72; 180 e 360 g e.a. ha-1), aplicadas quando as plantas se encontravam em estádio V4, e três regimes de fornecimento de água (fornecimento contínuo, RH1 e RH2). Foram avaliados o consumo de água diário, o perfilhamento e o acúmulo de massa das plantas. A aplicação de subdoses de glyphosate em condições de campo não influenciou a produtividade e os componentes de produtividade das plantas de arroz até a dose de 60 g e.a. ha-1 de glyphosate quando a aplicação ocorreu em V3, e até 30 g e.a. ha-1 de glyphosate quando a aplicação ocorreu em R1. A partir destas doses, houve severo efeito de intoxicação da cultura. Observou-se que os diferentes períodos de chuva após a aplicação de subdoses de glyphosate não interferiram na resposta das plantas de arroz aos tratamentos. Não foi observado efeito hormético para acúmulo de biomassa e consumo de água em casa de vegetação. A aplicação de doses entre 30 e 240 g e.a. ha-1 de glyphosate proporcionou incremento do perfilhamento das plantas de arroz em todos os estudos realizados, sendo a dose que causou incremento dependente das condições de condução do estudo. / The use of toxic substances in plants, such as glyphosate, in doses much smaller than those recommended commercially can cause changes in variables such as growth, biomass accumulation, height, protein content and resistance to diseases. In this way, the objectives of this work were to carry out studies for a better understanding of the biochemical, physiological and phenological alterations of the paddy rice caused by glyphosate subdoses. Experiment 1 was carried out at the Experimental Farm Lageado, belonging to the College of Agronomic Sciences, FCA / UNESP, in Botucatu, Sao Paulo, in the agricultural years of 2015/2016 and 2016/2017. The experimental design was a randomized block arranged in a 2x7 factorial scheme, with the first factor being the glyphosate application time (V3 or R1) and the second herbicide dose (0, 7.5, 15, 30, 60, 120 and 240 g a.e. ha-1), with four replications. The productivity, panicle length, number of tillers per m², weight of 1000 grains, number of grains per panicle, spikelet fertility and the number of days between the application and the beginning of each phenological phase were evaluated. Experiments 2 and 3 were carried out in a greenhouse at the Weed Science Advanced Research Center (NUPAM), belonging to the Faculty of Agronomic Sciences, FCA / UNESP, in Botucatu, Sao Paulo. Experiment 2 was in a completely randomized design in a factorial scheme (7x3) with five replications. The factor one was doses of the herbicide glyphosate (0, 7.5, 15, 30, 60, 120 and 240 g a.e. ha-1) applied in the V3 and factor two was rainy periods after application (12, 24 hours and without rain). The tillering and mass accumulation of plants were evaluated. Experiment 3 was arranged in a completely randomized design in a factorial scheme (7x3) with four replications. The factor one consisted of ten doses of the herbicide glyphosate (0, 1.5, 3, 6, 12, 24, 36, 72, 180 and 360 g a.e. ha-1) applied when plants were in the V4 stage, and factor two was 3 water supply schemes (no stress, RH1 and RH2). Daily water consumption, tillering and plant mass accumulation were evaluated. The application of glyphosate subdoses under field conditions did not influence yield, productivity components or phenology of paddy rice plants up to the 60 g a.e. ha-1 of glyphosate when the application occurred in V3 and up to 30 g a.e. ha-1 of glyphosate when application occurred at R1. From these doses, there was a severe effect of intoxication of the culture. It was observed that different rainy periods after application of glyphosate subdoses did not interfere in the response of paddy rice plants to the treatments. At greenhouse conditions, no hormesis effect was observed for biomass accumulation and water consumption. The application of doses from 30 to 240 g a.e. ha-1 of glyphosate increased the tillering of paddy rice plants in all the studies carried out, being the dose that caused increment dependent of the conditions of conduction of each study.

Submitted by Gabrielle de Castro Macedo (gabriellecmacedo@gmail.com) on 2018-06-20T13:11:07Z No. of bitstreams: 1 Tese Gabrielle Macedo.pdf: 2924623 bytes, checksum: 4b8918b0972da3b9df9edec41f649cc1 (MD5) / Approved for entry into archive by Maria Lucia Martins Frederico null (mlucia@fca.unesp.br) on 2018-06-20T13:27:34Z (GMT) No. of bitstreams: 1 macedo_gc_dr_botfca.pdf: 2799467 bytes, checksum: 818166270a47ee728d7586d43b819ef6 (MD5) / Made available in DSpace on 2018-06-20T13:27:34Z (GMT). No. of bitstreams: 1 macedo_gc_dr_botfca.pdf: 2799467 bytes, checksum: 818166270a47ee728d7586d43b819ef6 (MD5) Previous issue date: 2018-06-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O emprego de substâncias tóxicas as plantas, como o glyphosate, em doses muito menores que as recomendadas comercialmente pode ocasionar alterações em varáveis como crescimento, acúmulo de biomassa, altura, conteúdo de proteína e resistência a doenças. Desta forma, os objetivos deste trabalho foram realizar estudos para uma melhor compreensão das alterações bioquímicas, fisiológicas e fenológicas do arroz causadas por subdoses de glyphosate. O experimento 1 foi realizado à campo, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas, FCA/UNESP, Botucatu/SP, nos anos agrícolas de 2015/2016 e 2016/2017. O delineamento experimental utilizado foi o de blocos casualizados, arranjado em esquema fatorial 2x7, sendo o primeiro fator época de aplicação do glyphosate (V3 ou R1) e, o segundo, as doses do herbicida (0; 7,5; 15; 30; 60; 120 e 240 g e.a. ha-1), com quatro repetições. Foram avaliados a produtividade, o comprimento de panículas, número de perfilhos por m², peso de 1000 grãos, número de grãos por panícula, a fertilidade de espiguetas e o número de dias entre a aplicação e o início de cada fase fenológica. Os experimentos 2 e 3 foram realizados em casa de vegetação, no Núcleo de Pesquisas Avançadas em Matologia (NUPAM), pertecentente à Faculdade de Ciências Agronômicas, FCA/UNESP, Botucatu/SP. O experimento 2 seguiu delineamento inteiramente casualizado em esquema fatorial (7x3) com cinco repetições. Os tratamentos foram constituídos por sete doses do herbicida glyphosate (0; 7,5; 15; 30; 60; 120 e 240 g e.a. ha-1) aplicados no estádio V3, e 3 períodos de chuva após a aplicação (12, 24 horas e ausência). Foram avaliados o perfilhamento e o acúmulo de massa das plantas. O experimento 3 foi arranjado em delineamento inteiramente casualizado em esquema fatorial (7x3) com quatro repetições. Os tratamentos foram constituídos por dez doses do herbicida glyphosate (0; 1,5; 3; 6; 12; 24; 36; 72; 180 e 360 g e.a. ha-1), aplicadas quando as plantas se encontravam em estádio V4, e três regimes de fornecimento de água (fornecimento contínuo, RH1 e RH2). Foram avaliados o consumo de água diário, o perfilhamento e o acúmulo de massa das plantas. A aplicação de subdoses de glyphosate em condições de campo não influenciou a produtividade e os componentes de produtividade das plantas de arroz até a dose de 60 g e.a. ha-1 de glyphosate quando a aplicação ocorreu em V3, e até 30 g e.a. ha-1 de glyphosate quando a aplicação ocorreu em R1. A partir destas doses, houve severo efeito de intoxicação da cultura. Observou-se que os diferentes períodos de chuva após a aplicação de subdoses de glyphosate não interferiram na resposta das plantas de arroz aos tratamentos. Não foi observado efeito hormético para acúmulo de biomassa e consumo de água em casa de vegetação. A aplicação de doses entre 30 e 240 g e.a. ha-1 de glyphosate proporcionou incremento do perfilhamento das plantas de arroz em todos os estudos realizados, sendo a dose que causou incremento dependente das condições de condução do estudo. / The use of toxic substances in plants, such as glyphosate, in doses much smaller than those recommended commercially can cause changes in variables such as growth, biomass accumulation, height, protein content and resistance to diseases. In this way, the objectives of this work were to carry out studies for a better understanding of the biochemical, physiological and phenological alterations of the paddy rice caused by glyphosate subdoses. Experiment 1 was carried out at the Experimental Farm Lageado, belonging to the College of Agronomic Sciences, FCA / UNESP, in Botucatu, Sao Paulo, in the agricultural years of 2015/2016 and 2016/2017. The experimental design was a randomized block arranged in a 2x7 factorial scheme, with the first factor being the glyphosate application time (V3 or R1) and the second herbicide dose (0, 7.5, 15, 30, 60, 120 and 240 g a.e. ha-1), with four replications. The productivity, panicle length, number of tillers per m², weight of 1000 grains, number of grains per panicle, spikelet fertility and the number of days between the application and the beginning of each phenological phase were evaluated. Experiments 2 and 3 were carried out in a greenhouse at the Weed Science Advanced Research Center (NUPAM), belonging to the Faculty of Agronomic Sciences, FCA / UNESP, in Botucatu, Sao Paulo. Experiment 2 was in a completely randomized design in a factorial scheme (7x3) with five replications. The factor one was doses of the herbicide glyphosate (0, 7.5, 15, 30, 60, 120 and 240 g a.e. ha-1) applied in the V3 and factor two was rainy periods after application (12, 24 hours and without rain). The tillering and mass accumulation of plants were evaluated. Experiment 3 was arranged in a completely randomized design in a factorial scheme (7x3) with four replications. The factor one consisted of ten doses of the herbicide glyphosate (0, 1.5, 3, 6, 12, 24, 36, 72, 180 and 360 g a.e. ha-1) applied when plants were in the V4 stage, and factor two was 3 water supply schemes (no stress, RH1 and RH2). Daily water consumption, tillering and plant mass accumulation were evaluated. The application of glyphosate subdoses under field conditions did not influence yield, productivity components or phenology of paddy rice plants up to the 60 g a.e. ha-1 of glyphosate when the application occurred in V3 and up to 30 g a.e. ha-1 of glyphosate when application occurred at R1. From these doses, there was a severe effect of intoxication of the culture. It was observed that different rainy periods after application of glyphosate subdoses did not interfere in the response of paddy rice plants to the treatments. At greenhouse conditions, no hormesis effect was observed for biomass accumulation and water consumption. The application of doses from 30 to 240 g a.e. ha-1 of glyphosate increased the tillering of paddy rice plants in all the studies carried out, being the dose that caused increment dependent of the conditions of conduction of each study.

Submitted by CAROLINA PUCCI DE MORAES null (carolpuccim@gmail.com) on 2016-08-30T19:59:57Z No. of bitstreams: 1 Dissertacao_Carol Pucci de Moraes.pdf: 1638908 bytes, checksum: 3ee166e7d6818cac639935061f63d082 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-08-31T17:39:40Z (GMT) No. of bitstreams: 1 moraes_cp_me_bot.pdf: 1638908 bytes, checksum: 3ee166e7d6818cac639935061f63d082 (MD5) / Made available in DSpace on 2016-08-31T17:39:40Z (GMT). No. of bitstreams: 1 moraes_cp_me_bot.pdf: 1638908 bytes, checksum: 3ee166e7d6818cac639935061f63d082 (MD5) Previous issue date: 2016-07-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O efeito de estímulo de uma característica biológica por baixas doses de um composto considerado tóxico, mas que em altas doses tem efeito inibitório é denominado efeito hormesis. Estímulos de crescimento em plantas têm sido verificados após a aplicação de subdoses de alguns herbicidas, incluindo o glyphosate. Nesse contexto, o presente trabalho teve por objetivo avaliar as respostas de crescimento de plantas de Brachiaria decumbens submetidas a diferentes doses de glyphosate. Foram realizados dois estudos em casa de vegetação, ambos em delineamento inteiramente casualizado (DIC). No primeiro estudo foram realizados três experimentos com seis repetições, sendo no experimento 1 testada uma curva de dose-resposta com nove doses do herbicida glyphosate (0; 22,5; 45; 90; 180; 360; 720; 1440 e 2880 g e.a. ha-1). Nos experimentos dois e três foram aplicadas onze doses do herbicida glyphosate (0; 2,8125; 5,625; 11,25; 22,5; 45; 90; 180; 360; 720 e 1440 g e.a. ha-1). No estudo 2 para a avaliação de subdoses com efeito hormesis realizou-se quatro experimentos, em DIC com oito repetições e dois tratamentos (testemunha e dose de 11,25 g e.a. ha-1). Para ambos os estudos foram coletadas oito plantas de vasos sem aplicação para a determinação da biomassa inicial dos experimentos. Nos experimentos do estudo 1 foram realizadas avaliações de fitointoxicação aos 0, 7, 14 e 21 dias após a aplicação (DAA), além da coleta de oito plantas por vaso de cada tratamento para determinação de massa fresca e massa seca. Além disso, realizou-se a quantificação de massa fresca e seca total dos vasos aos 21 DAA, sendo essa metodologia também adotada para os experimentos do estudo 2. Os resultados do estudo 1 indicaram que: em doses acima de 45 g e.a. ha-1 foi possível obter 80% de controle das plantas de B. decumbens; a aplicação de baixas doses de glyphosate estimulou o aumento da biomassa das plantas de B. decumbens, com valores máximos alcançados na subdose de 11,25 g e.a. ha-1 de glyphosate. O segundo estudo indicou que a aplicação de subdose de 11,25 g e.a. ha-1 de glyphosate promoveu tanto estímulo quanto inibição de crescimento, demonstrando haver variabilidade de resposta das plantas à essa subdose.

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