Dissertations / Theses on the topic 'Herbicide resistance'
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Kershner, Kellan Scott. "Herbicide resistance in grain sorghum." Diss., Kansas State University, 2010. http://hdl.handle.net/2097/13069.
Full textDepartment of Agronomy
Kassim Al-Khatib
Mitchell R. Tuinstra
Sorghum acreage is declining throughout the United States because management options and yield have not maintained pace with maize improvements. The most extreme difference has been the absence of herbicide technology development for sorghum over the past twenty years. The objectives of this study were to evaluate the level of resistance, type of inheritance, and causal mutation of wild sorghums that are resistant to either acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicides or acetohydroxyacid synthase (AHAS)-inhibiting herbicides. ACCase-inhibiting herbicides used in this study were aryloxyphenoxypropionate (APP) family members fluazifop-P and quizalofop-P along with cyclohexanedione (CHD) family members clethodim and sethoxydim. The level of resistance was very high for APP herbicides but low to nonexistent to CHD herbicides. With genetic resistance to APP herbicides, the resistance factors, the ratio of resistance to susceptible, were greater than 54 to 64 for homozygous individuals and greater than 9 to 20 for heterozygous individuals. Resistance to CHD herbicides was very low with resistance factors ranging from one to about five. Genetic segregation studies indicate a single gene is the cause of resistance to APP herbicides. Sequencing identified a single mutation that results in cysteine replacing tryptophan (Trp-2027-Cys). Trp-2027-Cys has previously been reported to provide resistance to APP but not CHD herbicides. The other wild sorghum evaluated in this study was resistant to AHAS-inhibiting herbicides including imidazolinone (IM) family member, imazapyr, and sulfonylurea (SU) family member, nicosulfuron. Resistance factors in this genotype were very high, greater than 770 for the IM herbicide and greater than 500 for the SU herbicide, for both herbicide chemical families. Genetic segregation studies demonstrate that resistance was controlled by one major locus and two modifier loci. DNA sequencing of the AHAS gene identified two mutations, Val-560-Ile and Trp-574-Leu. Val-560-Ile is of unknown importance, but valine and isoleucine are similar and residue 560 is not conserved. Trp-574 is a conserved residue and Leu-574 is a known mutation that provides strong cross resistance to IM and SU herbicides. The results of these studies suggest that these sources of APP, SU, and IM resistance may provide useful herbicide resistance traits for use in sorghum.
Mansooji, Ali Mohammad. "Herbicide resistance in wild oats, Avena spp." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phm289.pdf.
Full textManeechote, Chanya. "Mechanisms of herbicide resistance in wild oats (Avena spp.)." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phm274.pdf.
Full textIwakami, Satoshi. "Molecular mechanism of resistance in a multiple-herbicide resistant Echinochloa phyllopogon." Kyoto University, 2013. http://hdl.handle.net/2433/180368.
Full text0048
新制・課程博士
博士(農学)
甲第17830号
農博第2015号
新制||農||1016(附属図書館)
学位論文||H25||N4787(農学部図書室)
30645
京都大学大学院農学研究科農学専攻
(主査)教授 稲村 達也, 教授 冨永 達, 教授 奥本 裕
学位規則第4条第1項該当
MacLean, Nancy L. "A study using in vitro selection to develop herbicide resistance in Lotus corniculatus /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65376.
Full textFleitz, Nicholas J. "COMPARISON OF SOIL-APPLIED AND POSTEMERGENCE HERBICIDES WITH MULTIPLE SITES OF HERBICIDAL ACTIVITY ON TWO POPULATIONS OF HERBICIDE-RESISTANT PALMER AMARANTH IN KENTUCKY." UKnowledge, 2018. https://uknowledge.uky.edu/pss_etds/99.
Full textLagator, Mato. "Experimental evolution of herbicide resistance in Chlamydomonas reinhardtii." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/56830/.
Full textMilner, Lucy J. "Herbicide resistance in black-grass (Alopecurus myosuroides Huds.)." Thesis, Open University, 2002. http://oro.open.ac.uk/54618/.
Full textDick, Rosemary Elaine. "Microbial degradation of the herbicide glyphosate." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336732.
Full textLi, Hwei-Yiing. "Mechanisms of action and selectivity of the cyclohexen-one herbicide cycloxydim (BAS 517)." Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/39985.
Full textPh. D.
Friesen, Lincoln Jacob Shane. "Identification of the mechanisms of wild radish herbicide resistance to PSII inhibitors, auxinics, and AHAS inhibitors." University of Western Australia. School of Plant Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0106.
Full textDixon, Peter Allan. "Herbicide resistance in wild oats : genetic variation and ecology." Thesis, University of Liverpool, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343857.
Full textSoar, Christopher J. "Study on the biochemical and physiological basis for resistance to paraquat in Arctotheca calendula (L.) Levyns (Capeweed)." Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09ACP/09acps676.pdf.
Full textScruggs, Eric Brandon. "Control and Fecundity of Palmer Amaranth (Amaranthus palmeri) and Common Ragweed (Ambrosia artemisiifolia) from Soybean Herbicides Applied at Various Growth and Development Stages." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98467.
Full textMaster of Science in Life Sciences
Over 30 million hectares of soybeans were harvested in 2019 in the United States, totaling over $31 billion in value. Two of the most troublesome weeds in soybean, Palmer amaranth (Amaranthus palmeri) and common ragweed (Ambrosia artemisiifolia) can cause even greater yield reductions in soybean, up to 79 to 95%, respectively. Frequent, exclusive, and repeated use of a single herbicide has led to multiple herbicide-resistance in both of these weeds. Co-applying two effective herbicides reduces the likelihood of resistance development. New soybean varieties have been genetically modified for resistance to herbicides that were previously unusable, allowing new herbicide combinations. Research was established to investigate these herbicide options to control and reduce seed production of Palmer amaranth and common ragweed with the overarching goal of mitigating herbicide resistance, particularly resistance to protoporphyrinogen oxidase (PPO) inhibiting herbicides, which are a critical part of herbicide options in soybean production. Preemergence herbicides are vital tools in herbicide programs, reducing the number of weeds present at a postemergence application and thereby reducing the risk of herbicide resistance development to the postemergence herbicide. PPO herbicides (flumioxazin, sulfentrazone, or fomesafen) applied preemergence reduced Palmer amaranth and common ragweed density at the postemergence application 82 to 89% and 53 to 94%, respectively. The preemergence herbicide used did not affect control four weeks after the postemergence herbicides were applied. Postemergence herbicides were applied targeting three weed heights: 5 to 10 cm (ideal), 10 to 20 cm, and 20 to 30 cm. Control decreased as weed height increased and larger weeds had greater biomass and seed production, underscoring the importance of proper herbicide application timing. The single site-of-action treatments dicamba, 2,4-D, glufosinate, or fomesafen resulted in greater than 85 and 92% morality of 5 to 10 cm Palmer amaranth and common ragweed, respectively. Palmer amaranth and common ragweed control improved by 19 to 25% and 14 to 19%, respectively, when using two herbicide sites-of-action increased versus using one SOA (mesotrione, dicamba, 2,4-D, or glufosinate alone). The use of two herbicide sites of action resulted in maximum biomass reductions, depending on weed height, of 57 to 96% and 73 to 85% for Palmer amaranth and common ragweed, respectively. Dicamba, 2,4-D, glufosinate alone and in combination with fomesafen reduced seed production (relative to the nontreated) of 5 to 10 cm Palmer amaranth and common ragweed greater than 98 and 76%, respectively. Dicamba, 2,4-D, and glufosinate applied alone or auxin (dicamba and 2,4-D) and glufosinate combinations reduced Palmer amaranth seed production greater than 95% when applied at first visible female inflorescence. This indicates that these herbicides may be useful in soil weed seed bank management. This research reinforces the utility of PPO herbicides for preemergence control and their efficacy postemergence when combined with another effective herbicide, a practice known to reduce herbicide resistance development. This research also reinforces the potential for dicamba, 2,4-D, or glufosinate to reduce weed seed production when applied at a delayed timing. Future research should investigate the progeny of these weeds treated with herbicides at a delayed timing to evaluate the potential for this practice to reduce herbicide resistance development.
Gomes, Giovanna Larissa Gimenes Cotrick [UNESP]. "Caracterização bioquímica e morfofisiológica de populações de buva (Conyza spp.) resistentes ao glyphosate." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/116041.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste trabalho foi caracterizar quatro populações de Conyza spp. bioquimicamente e morfofisiologicamente. Os experimentos foram realizados em casa de vegetação com quatro populações (P1, P3 e P4 – Conyza sumatrensis; P2 – Conyza bonariensis) que foram coletados em diferentes municípios do estado de São Paulo. Os tratamentos foram constituídos da aplicação de doses do herbicida glyphosate: 45, 90, 180, 360, 720, 1440, 2880, 5760 e 11520 g e.a. ha-1; e uma testemunha sem aplicação. No momento da aplicação as plantas apresentavam de 5 a 6 folhas totalmente expandidas. Foi realizado um estudo preliminar e mais três estudos, com os mesmos tratamentos, mas com avaliações distintas. O estudo preliminar foi composto de um experimento com a população 4, onde foram avaliados aos 28 dias após os tratamentos (DAT) a altura das plantas, porcentagem de controle, massa fresca de parte aérea, e quantificação dos seguintes compostos por cromatografia líquida de alta eficiência e espectrometria de massas (LCMS/ MS): glyphosate, ácido aminometilfosfônico (AMPA), ácido chiquímico, ácido desidrochiquímico, fenilalanina, tirosina, triptofano, e ácido salicílico. No primeiro estudo foram realizadas as curvas de dose resposta para as quatro populações testadas. No estudo seguinte, aos 14 DAT foi realizada a coleta de todas as folhas de cada planta (repetição) para quantificação dos mesmos compostos já descritos no estudo preliminar, além do ácido indolacético (IAA) e ácido abscísico (ABA) por LC-MS/MS. O último estudo teve como objetivo avaliar o crescimento, florescimento e produção de sementes, por meio de avaliações de altura, número de brotações laterais, número de capítulos abertos e número ...
The objective of this research was to characterize four Conyza spp. populations biochemically and morphophisiologically. The experiments were carried out in a greenhouse with four populations (P 1, 3 and 4 - Conyza sumatrensis; P 2 - Conyza bonariensis). Seeds were collected in different municipalities of the Sao Paulo state. The treatments consisted of the glyphosate application in different doses: 45, 90, 180, 360, 720, 1440, 2880, 5760 and 11520 g ae ha-1 and one untreated control. The herbicide glyphosate was applied to plants with 5-6 expanded leaves. Were performed a preliminary study and three others studies, with the same treatments but with different evaluations. The preliminary study consisted of an experiment with population 4, which was evaluated at 28 days after treatment (DAT) the plant height, percentage of control, fresh weight of plants, and quantitation of glyphosate, aminomethylphosphonic acid (AMPA), shikimic acid, dehydroshikimic acid, phenylalanine, tyrosine, tryptophan, and salicylic acid by LC-MS/MS. In the first study, the dose response curves were performed. In the following study, at 14 DAT, all the leaves of each plant were ...
Gomes, Giovanna Larissa Gimenes Cotrick 1985. "Caracterização bioquímica e morfofisiológica de populações de buva (Conyza spp.) resistentes ao glyphosate /." Botucatu, 2014. http://hdl.handle.net/11449/116041.
Full textBanca: Fernando Tadeu de Carvalho
Banca: Fernando Storniolo Adegas
Banca: Eduardo Negrisoli
Banca: Pedro Jaccob Christoffoleti
Resumo: O objetivo deste trabalho foi caracterizar quatro populações de Conyza spp. bioquimicamente e morfofisiologicamente. Os experimentos foram realizados em casa de vegetação com quatro populações (P1, P3 e P4 - Conyza sumatrensis; P2 - Conyza bonariensis) que foram coletados em diferentes municípios do estado de São Paulo. Os tratamentos foram constituídos da aplicação de doses do herbicida glyphosate: 45, 90, 180, 360, 720, 1440, 2880, 5760 e 11520 g e.a. ha-1; e uma testemunha sem aplicação. No momento da aplicação as plantas apresentavam de 5 a 6 folhas totalmente expandidas. Foi realizado um estudo preliminar e mais três estudos, com os mesmos tratamentos, mas com avaliações distintas. O estudo preliminar foi composto de um experimento com a população 4, onde foram avaliados aos 28 dias após os tratamentos (DAT) a altura das plantas, porcentagem de controle, massa fresca de parte aérea, e quantificação dos seguintes compostos por cromatografia líquida de alta eficiência e espectrometria de massas (LCMS/ MS): glyphosate, ácido aminometilfosfônico (AMPA), ácido chiquímico, ácido desidrochiquímico, fenilalanina, tirosina, triptofano, e ácido salicílico. No primeiro estudo foram realizadas as curvas de dose resposta para as quatro populações testadas. No estudo seguinte, aos 14 DAT foi realizada a coleta de todas as folhas de cada planta (repetição) para quantificação dos mesmos compostos já descritos no estudo preliminar, além do ácido indolacético (IAA) e ácido abscísico (ABA) por LC-MS/MS. O último estudo teve como objetivo avaliar o crescimento, florescimento e produção de sementes, por meio de avaliações de altura, número de brotações laterais, número de capítulos abertos e número ...
Abstract: The objective of this research was to characterize four Conyza spp. populations biochemically and morphophisiologically. The experiments were carried out in a greenhouse with four populations (P 1, 3 and 4 - Conyza sumatrensis; P 2 - Conyza bonariensis). Seeds were collected in different municipalities of the Sao Paulo state. The treatments consisted of the glyphosate application in different doses: 45, 90, 180, 360, 720, 1440, 2880, 5760 and 11520 g ae ha-1 and one untreated control. The herbicide glyphosate was applied to plants with 5-6 expanded leaves. Were performed a preliminary study and three others studies, with the same treatments but with different evaluations. The preliminary study consisted of an experiment with population 4, which was evaluated at 28 days after treatment (DAT) the plant height, percentage of control, fresh weight of plants, and quantitation of glyphosate, aminomethylphosphonic acid (AMPA), shikimic acid, dehydroshikimic acid, phenylalanine, tyrosine, tryptophan, and salicylic acid by LC-MS/MS. In the first study, the dose response curves were performed. In the following study, at 14 DAT, all the leaves of each plant were ...
Doutor
Welgama, Amali. "Herbicide application strategies for wild radish management in Imidazolinone tolerant faba bean." Thesis, Federation University Australia, 2020. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/176148.
Full textDoctor of Philosophy
Nietschke, Brett Steven. "Integrated strategies for wild oat (Avena spp.) management in southern Australian farming systems." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phn677.pdf.
Full textPoston, Daniel Hasford. "Growth Analyses and Patterns of Cross-Resistance in Four Imidazolinone-Resistant Smooth Pigweed (Amaranthus hybridus) Populations." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/29151.
Full textPh. D.
Milligan, Andrew Simon. "Wheat biotechnology : engineered herbicide resistance and inducible promoters for transgene expression." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326968.
Full textUlf-Hansen, Peter Fleming. "The dynamics of natural selection for herbicide resistance in grass weeds." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240807.
Full textNIÑA, GRACEL BAYLA DIMAANO. "STUDY ON THE METABOLISM-BASED RESISTANCE IN A MULTIPLE HERBICIDE RESISTANT LINE OF Echinochloa phyllopogon (Stapf) Koss." Kyoto University, 2019. http://hdl.handle.net/2433/244561.
Full textBlyden, E. R. "Molecular genetics of triazine resistance in Senecio vulgaris L." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383076.
Full textKrenchinski, Fabio Henrique 1991. "Glufosinate e associações com herbicidas em tecnologias de milho com o gene fosfinotricina acetyltransferase /." Botucatu, 2018. http://hdl.handle.net/11449/155863.
Full textCoorientador: Alfredo Junior Paiola Albrecht
Banca: Edivaldo Domingues Velini
Banca: Leandro Paiola Albrecht
Resumo: O gene fosfinotricina acetyltransferase (pat) produz a enzima PAT, que por n-acetilação é capaz de metabolizar o glufosinate, transformando-o em n-acetyl-L-glufosinate (NAG). Assim, plantas transgênicas contendo esse gene resistem às aplicações desse herbicida. No milho, esse gene foi inserido como marcador de seleção e mais estudos precisam ser realizados a fim de validar o uso dessa tecnologia. Nesse contexto, os objetivos do presente trabalho foram avaliar se a expressão do gene pat é proporcional ao nível de resistência de tecnologias de milho à aplicação de glufosinate e avaliar a seletividade de herbicidas em associação ao glufosinate em milho com o gene pat. Durante o primeiro trabalho, foram utilizados híbridos de milho com as tecnologias Herculex®; Agrisure TL®; Herculex Yieldgard®; Leptra®; Viptera 3®; Power Core® com o gene pat e VT PRO® sem o gene pat. Para isso, um experimento foi realizado para avaliar a expressão relativa do gene pat nos híbridos de milho, por meio de PCR em tempo real. Em outro estudo, foram aplicadas doses de glufosinate (0, 500, 1000, 2000 e 4000 g i.a ha-1) sobre os híbridos de milho, no qual foram avaliados os teores de glufosinate e NAG, assim como acúmulo de amônia, taxa de transporte de elétrons (ETR), injúria visual e acúmulo de biomassa. Em campo, foi realizada a aplicação de 500 g i.a ha-1 de glufosinate durante o estádio V4 do milho, e foi avaliado o rendimento de grãos. Um segundo estudo foi realizado a campo, adotando-se a tecnolo... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The phosphinothricin acetyltransferase (pat) gene produces the enzyme PAT, which by n-acetylation is able to metabolize the glufosinate, transforming it into n-acetyl-L-glufosinate (NAG). So transgenic plants containing this gene resist the applications of this herbicide. In corn, this gene was inserted as a selection marker and further studies are needed to be performed to validate this technology use. In this context, the objectives of the present work were to evaluate if the expression of the pat gene is proportional to the resistance level of maize technologies submitted to the application of glufosinate and also to evaluate the selectivity of some others herbicides in association with glufosinate in maize which presents the pat gene. For the first work, the technologies used were: Herculex®; Agrisure TL®; Herculex Yieldgard®; Leptra®; Viptera 3®; Power Core® with the pat gene and VT PRO® without the pat gene. For this, an experiment was carried out to evaluate the relative expression of the pat gene in the technologies by RT- PCR. In another study, glufosinate (0, 500, 1000, 2000 and 4000 g a.i ha-1) doses were applied to the technologies, in which the glufosinate and NGA contents, ammonia accumulation, electron transportation rate (ETR), visual injury and biomass accumulation were evaluated. In the field, the spraying of 500 g a.i ha-1 of glufosinate in the V4 stage of maize was carried out in the technologies and grain yield was measured. For the second study the Power Core® technology was adopted, and the experiment was carried out in the field. The treatments were: glufosinate; glyphosate; glufosinate + glyphosate; glufosinate + nicosulfuron; glufosinate + atrazine; glufosinate + tembotrione; glufosinate + mesotrione; glufosinate + carfentrazone ethyl; glufosinate + bentazon; glufosinate + 2,4-D; no-weeding control and weeding control. Evaluations of visual injury, ETR, ammonia ...
Mestre
Girotto, Marcelo [UNESP]. "Respostas de populações autógamas de Avena fátua à seleção por baixas doses de diclofop-methyl e glyphosate." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/127907.
Full textSe aplicados no estágio e na dose correta, os herbicidas são altamente tóxicos para as plantas. As populações de plantas daninhas suscetíveis a um determinado herbicida são totalmente controladas quando a dose recomendada é corretamente aplicada. No entanto, há uma evolução contínua na sobrevivência e crescimento das plantas em resposta a baixas doses dos herbicidas como resultado da presença de características que podem causar um baixo nível de resistência a estes produtos. Estudos de seleção recorrente podem revelar se a variação fenotípica em resposta a uma dose baixa do herbicida é hereditária e pode conduzir à resistência ao herbicida. Estudos de seleção recorrente de plantas alógamas de Lolium rigidum sobreviventes baixas doses de herbicidas mostraram rápida evolução da resistência a herbicidas em apenas três gerações por intensificação progressiva de características de resistência a herbicidas inicialmente pouco relevantes. Em um estudo de campo, populações autógamas de Avena fatua foram submetidas a um processo de seleção recorrente resultante da aplicação de baixas doses do herbicida diclofop-methyl (inibidor da ACCase) ou o glyphosate (inibidor da EPSPS). As aplicações sucessivas de diclofop-methyl induziram o desenvolvimento de progênies distintas da população original em termos de resistência a este herbicida, com o aumento de duas vezes na LD50. As progênies selecionadas pelo uso de diclofop-methyl também mostraram-se mais resistentes a herbicidas inibidores da ALS indicando sugerindo a ocorrência de resistência cruzada. As aplicações sucessivas de glyphosate não induziram a formação de progênies mais resistentes. A capacidade da A. fatua para responder à pressão de seleção imposta por baixas doses de herbicidas é limitada e muito mais baixa ...
Herbicides when applied at the correct stage and dose are highly toxic to plants. Herbicide-susceptible weed populations are completely controlled at the recommended herbicide label dose. However, there is continuous variation in plant survival and growth in response to herbicide low doses (below-label) because specific plant traits can confer some low level resistance. Recurrent (directional) selection studies can reveal whether such a phenotypic variation in response to a herbicide low dose is heritable and can lead to herbicide resistance. Recurrent selection studies with allogamous cross-pollinated Lolium rigidum plants surviving at a low herbicide dose showed rapid evolution of herbicide resistance in three generations by progressive enrichment of minor herbicide resistance traits. In a common experimental garden study, we have subjected to low-dose recurrent selection a susceptible population of autogamous self-pollinated Avena fatua with the ACCase-inhibiting herbicide diclofop-methyl or the EPSPS-inhibiting glyphosate. Significant differences in response to selection between the selected progenies and parents were evident in the lines selected by low-dose diclofop-methyl, whereas glyphosate selection did not results in significant shifts. A two-fold diclofop resistance was quantified by comparison of estimated LD50 values and a significant increase in survival to ALS-inhibiting herbicides suggests cross-resistance. Importantly, the capacity of A. fatua to respond to low-dose herbicide selection is marginal and much lower than in L. rigidum. The dynamics of selection and the factors driving the evolution of resistance to herbicides in plants are discussed with particular emphasis on the implications of low-dose herbicide use weed management of autogamous self-pollinated vs allogamous cross ...
Girotto, Marcelo 1984. "Respostas de populações autógamas de Avena fátua à seleção por baixas doses de diclofop-methyl e glyphosate /." Botucatu, 2015. http://hdl.handle.net/11449/127907.
Full textCoorientador: Stephen Powles
Coorientador: Roberto Busi
Banca: Caio Antonio Carbonari
Banca: Roberto Estevão Bragion de Toledo
Banca: Ramiro Fernando Lopez Ovejero
Banca: Eduardo Negrisoli
Resumo: Se aplicados no estágio e na dose correta, os herbicidas são altamente tóxicos para as plantas. As populações de plantas daninhas suscetíveis a um determinado herbicida são totalmente controladas quando a dose recomendada é corretamente aplicada. No entanto, há uma evolução contínua na sobrevivência e crescimento das plantas em resposta a baixas doses dos herbicidas como resultado da presença de características que podem causar um baixo nível de resistência a estes produtos. Estudos de seleção recorrente podem revelar se a variação fenotípica em resposta a uma dose baixa do herbicida é hereditária e pode conduzir à resistência ao herbicida. Estudos de seleção recorrente de plantas alógamas de Lolium rigidum sobreviventes baixas doses de herbicidas mostraram rápida evolução da resistência a herbicidas em apenas três gerações por intensificação progressiva de características de resistência a herbicidas inicialmente pouco relevantes. Em um estudo de campo, populações autógamas de Avena fatua foram submetidas a um processo de seleção recorrente resultante da aplicação de baixas doses do herbicida diclofop-methyl (inibidor da ACCase) ou o glyphosate (inibidor da EPSPS). As aplicações sucessivas de diclofop-methyl induziram o desenvolvimento de progênies distintas da população original em termos de resistência a este herbicida, com o aumento de duas vezes na LD50. As progênies selecionadas pelo uso de diclofop-methyl também mostraram-se mais resistentes a herbicidas inibidores da ALS indicando sugerindo a ocorrência de resistência cruzada. As aplicações sucessivas de glyphosate não induziram a formação de progênies mais resistentes. A capacidade da A. fatua para responder à pressão de seleção imposta por baixas doses de herbicidas é limitada e muito mais baixa ...
Abstract: Herbicides when applied at the correct stage and dose are highly toxic to plants. Herbicide-susceptible weed populations are completely controlled at the recommended herbicide label dose. However, there is continuous variation in plant survival and growth in response to herbicide low doses (below-label) because specific plant traits can confer some low level resistance. Recurrent (directional) selection studies can reveal whether such a phenotypic variation in response to a herbicide low dose is heritable and can lead to herbicide resistance. Recurrent selection studies with allogamous cross-pollinated Lolium rigidum plants surviving at a low herbicide dose showed rapid evolution of herbicide resistance in three generations by progressive enrichment of minor herbicide resistance traits. In a common experimental garden study, we have subjected to low-dose recurrent selection a susceptible population of autogamous self-pollinated Avena fatua with the ACCase-inhibiting herbicide diclofop-methyl or the EPSPS-inhibiting glyphosate. Significant differences in response to selection between the selected progenies and parents were evident in the lines selected by low-dose diclofop-methyl, whereas glyphosate selection did not results in significant shifts. A two-fold diclofop resistance was quantified by comparison of estimated LD50 values and a significant increase in survival to ALS-inhibiting herbicides suggests cross-resistance. Importantly, the capacity of A. fatua to respond to low-dose herbicide selection is marginal and much lower than in L. rigidum. The dynamics of selection and the factors driving the evolution of resistance to herbicides in plants are discussed with particular emphasis on the implications of low-dose herbicide use weed management of autogamous self-pollinated vs allogamous cross ...
Doutor
Pofelis, Shoshana. "The development of sulfonylurea herbicide resistant birdsfoot trefoil (Lotus corniculatus) plants from in vitro selection /." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60086.
Full textGodar, Amar Singh. "Glyphosate resistance in kochia." Diss., Kansas State University, 2013. http://hdl.handle.net/2097/16954.
Full textDepartment of Agronomy
Phillip W. Stahlman
Kochia [Kochia scoparia (L.) Schrad.] is a weed of great economic importance in the Great Plains and western United States and Canada. This weed is prone to evolving resistance to herbicides. Glyphosate is the most widely used herbicide in glyphosate-resistant crops and chemical fallow, and is extremely valuable to crop production. Anecdotal reports of kochia control failure with glyphosate in western Kansas arose during the mid-2000’s. The objectives of this research were to (1) confirm and characterize glyphosate resistance in kochia and measure its impact in western Kansas, (2) gather information on grower weed management practices before and since glyphosate resistance in kochia was confirmed, and (3) determine if altered absorption and translocation of glyphosate contributes to glyphosate resistance in kochia. Dose-response studies on greenhouse and outdoor grown plants, and shikimate accumulation assays confirmed one kochia population collected in 2007 and eight populations collected in 2010 tolerated three- to eleven-times more glyphosate compared to a known glyphosate-susceptible (GS) population. Furthermore, 40 kochia populations collected in 2012 showed varied response, from slightly elevated tolerance to resistance to 0.84 kg ae ha-1 glyphosate. Further analysis suggested these populations were at different stages of resistance evolution. An online survey revealed that growers increased glyphosate use rate and application frequency, but decreased exclusive use of glyphosate and diversified weed management practices during post- compared to pre-glyphosate confirmation periods. Most survey respondents reported presence of glyphosate-resistant (GR) kochia in at least in few fields, and half reported GR kochia in a majority of fields. Thus, together with the resistance confirmation studies, it is estimated that at least one-third of western Kansas kochia populations have evolved resistance to glyphosate. Nominal differences in absorption and translocation of 14C-glyphosate observed between GS and GR kochia populations likely do not contribute to differential response of these populations to glyphosate. Glyphosate-resistant kochia has become widespread in western Kansas in a short period of time. Use of weed resistance best management practices (BMP) is imperative to sustain the utility of glyphosate in the region.
Sharples, Catherine Ruth. "An investigation of herbicide resistance in black-grass using safeners and synergists." Thesis, Nottingham Trent University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320598.
Full textKnight, Craig Martin. "Investigating the evolution of herbicide resistance in UK populations of Alopecurus myosuroides." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/77761/.
Full textWortley, David. "The role of glutathione transferases in multiple herbicide resistance in grass weeds." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/4702/.
Full textPurba, Edison. "Factors influencing the development of resistance to the bipyridyl herbicides in Australia." Title page, contents and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09php9852.pdf.
Full textParrish, Jason Thomas. "Investigations into Multiple–Herbicide-Resistant Ambrosia artemisiifolia (Common Ragweed) in Ohio and Glyphosate-Resistance Mechanisms." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1420789335.
Full textHustedde, Nicholas Victor. "Optimum® GAT® Concepts: Herbicide Combinations for Foliar and Residual Weed Control in Soybean and Corn." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/604.
Full textPicoli, Junior Gilmar José 1987. "Influência do glyphosate no perfil bioquímico e fisiológico de populações de azevém (Lolium multiflorum) suscetíveis e resistentes ao herbicida /." Botucatu, 2016. http://hdl.handle.net/11449/135868.
Full textCoorientador: Edivaldo Domingues Velini
Banca: Giuseppina Pace Pereira Lima
Banca: Eduardo Negrisoli
Banca: Roberto Estevão Bragion de Toledo
Banca: Ricardo Victoria Filho
Resumo: No Brasil, o azevém (Lolium multiflorum) foi identificado como resistente ao glyphosate se tornando um grande problema em determinadas lavouras. Dessa forma, entender o comportamento a nível bioquímico e fisiológico desta planta daninha são ferramentas que auxiliam num manejo eficiente. Com isso, o objetivo deste trabalho foi comparar o perfil bioquímico e fisiológico de populações de azevém suscetíveis e resistentes ao herbicida glyphosate aplicação do mesmo. Foram realizados quatro estudos em casa-de-vegetação com delineamento experimental inteiramente casualizados com quatro repetições sendo semeadas três populações de azevém (Lolium multiflorum) consideradas como suscetível (S), com suspeita de resistência (R1) e resistente (R2) ao herbicida glyphosate. No primeiro estudo foi obtido o controle aos 21 dias após a aplicação (DAA) e quantificada a massa seca aos 28 DAA das três populações. Os tratamentos foram constituídos da aplicação do herbicida glyphosate composto pelas doses: 0, 135, 270, 540, 1080, 2160, 4320, 8640 g e.a. ha-1. O segundo estudo teve como objetivo determinar a atividade da enzima fenilalanina amônia liase (PAL) nas diferentes populações as 12, 24, 48 e 72 horas após a aplicação (HAA). Os tratamentos foram compostos de duas doses (720 g e.a. ha-1 e 1080 g e.a. ha-1) mais uma testemunha sem aplicação. No terceiro estudo foram realizadas avaliações da fotossíntese nas três populações ao 1, 3, 7 e 28 DAA. As variáveis analisadas foram: taxa de assimilação líquida de CO2, condutância estomática, concentração interna de CO2, transpiração, eficiência do uso da água e eficiência instantânea de carboxilação. Os tratamentos foram compostos de duas doses (720 g e.a. ha-1 e 1080 g e.a. ha-1) mais uma testemunha sem aplicação. O quarto estudo teve o objetivo de quantificar compostos alterados da rota do ácido chiquímico. Para ...
Abstract: In Brazil, ryegrass (Lolium multiflorum) was identified as resistant to glyphosate becoming a major problem in certain crops. Thus, understanding the behavior of the biochemical and physiological level of this weed are tools that help in efficient management. Thus, the aim of this study was to compare the biochemical and physiological profile of ryegrass populations susceptible and resistant to glyphosate after spray it. Four studies were carried out in greenhouse with experimental design completely randomized with four replications being seeded three populations of ryegrass (Lolium multiflorum) considered as susceptible (S), suspected of having resistance (R1) and resistant (R2) to the herbicide glyphosate. In the first study was measured the control at 21 days after application (DAA) and at 28 DAA, the dry mass the three populations. The treatments consisted of application of the glyphosate composed of doses: 0, 135, 270, 540, 1080, 2160, 4320, 8640 g a.i. ha-1. The second study aimed to determine the phenylalanine ammonia lyase (PAL) activity in different populations at 12, 24, 48 and 72 hours after application (HAA). The treatments consisted of two doses (720 g a.i. ha-1 and 1080 g a.i. ha-1) plus a control without application. In the third study were carried out photosynthesis assessments at three populations at 1, 3, 7 and 28 DAA. The variables analyzed were: CO2 net assimilation rate, stomatal conductance, CO2 internal concentration, transpiration, water use efficiency and instantaneous carboxylation efficiency. The treatments consisted of two doses (720 g a.i. ha-1 and 1080 g a.i. ha-1) plus a control without application. The fourth study aimed to quantify altered compounds of the shikimic acid pathway. For this, the same treatments of the first experiment were used and made collections of leaves at 5, 11, 28 DAA. The compounds analyzed were: glyphosate, AMPA (aminomethylphosphonic acid) ...
Doutor
Dallastra, Anderson [UNESP]. "Abordagem multivariada na seleção de progênies de soja superiores e portadoras do gene RR." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/92647.
Full textO melhoramento genético de plantas é considerado um processo complexo que gera múltiplas informações e, em muitos casos, de difícil compreensão. O objetivo deste trabalho foi selecionar progênies com caracteres superiores provenientes de cruzamentos bi-parentais de soja com fonte de resistência ao glifosato (RR), além de identificar cruzamentos e genitores mais eficientes, por meio de abordagens multivariadas. Além disso, objetivou-se ainda testar a eficiência dos métodos no processo seletivo para múltiplos caracteres de interesse. O experimento foi conduzido no delineamento experimental do tipo famílias com testemunhas intercalares, no ano agrícola 2010/2011 e 2011/2012 em Jaboticabal-SP sendo que, nas populações F3 foram selecionadas seis plantas fenotipicamente superiores e avaliadas para os caracteres: número de dias para o florescimento (NDF), número de dias para a maturidade (NDM), altura de inserção da primeira vagem (AIV), altura de planta na maturidade (APM), acamamento (Ac), valor agronômico (VA), número de ramos (NR), número de vagens por planta (NV), peso de cem sementes (PCS), número de sementes por planta (NS) e produção de grãos (PG). Os dados foram analisados utilizando-se o software Statistica 7.0. Os resultados obtidos possibilitaram a seleção de 77 progênies superiores através da Análise de Componentes Principais. A análise de Agrupamentos, pelo do método de K-means, agregou as progênies em seis grupos de acordo com os caracteres de maior importância em cada um e, através do método de Ward, identificou por meio do dendrograma a estrutura de similaridade e divergência entre as progênies selecionadas. Por fim, comparou-se os métodos de agrupamentos e verificou-se que houve concordância entre ambos quanto aos resultados obtidos
The plant breeding is considered to be a complex process that generates multiple information sources and in many cases, difficult to understand. The aim of this work was to select progenies with superior characters from bi-parental crosses with soy source of resistance to glyphosate (RR), and identify intersections and parents more efficient through multivariate approaches. Furthermore, aimed to further test the efficiency of the methods in the selection process for multiple traits of interest. The experiment was conducted in the experimental design of type families to witness progress in the agricultural year 2010/2011 and 2011/2012 in Jaboticabal being that in F3 populations selected six plants were phenotypically superior and evaluated for the traits: number of days to flowering (NDF), number of days to maturity (NDM), height of the first pod (AIV), plant height at maturity (APM), lodging (Ac), agronomic value (VA), number of branches (NR), number of pods per plant (NV), one hundred seed weight (PCS), number of seeds per plant (NS) and grain yield (GY). Data were analyzed using the software Statistica 7.0. The results allowed the selection of 77 superior progenies by Principal Component Analysis. Cluster analysis by the K-means method, all progenies added into six groups according to the characters in each of utmost importance, and by the method of Ward identified by the dendrogram structure similarity and divergence between the progenies. Finally, we compared the clustering methods and found that there was an agreement between them as to the results obtained
Dallastra, Anderson. "Abordagem multivariada na seleção de progênies de soja superiores e portadoras do gene RR /." Jaboticabal, 2013. http://hdl.handle.net/11449/92647.
Full textCoorientador: Antonio Orlando Di Mauro
Banca: Dilermando Perecin
Banca: João Antônio da Costa Andrade
Resumo: O melhoramento genético de plantas é considerado um processo complexo que gera múltiplas informações e, em muitos casos, de difícil compreensão. O objetivo deste trabalho foi selecionar progênies com caracteres superiores provenientes de cruzamentos bi-parentais de soja com fonte de resistência ao glifosato (RR), além de identificar cruzamentos e genitores mais eficientes, por meio de abordagens multivariadas. Além disso, objetivou-se ainda testar a eficiência dos métodos no processo seletivo para múltiplos caracteres de interesse. O experimento foi conduzido no delineamento experimental do tipo famílias com testemunhas intercalares, no ano agrícola 2010/2011 e 2011/2012 em Jaboticabal-SP sendo que, nas populações F3 foram selecionadas seis plantas fenotipicamente superiores e avaliadas para os caracteres: número de dias para o florescimento (NDF), número de dias para a maturidade (NDM), altura de inserção da primeira vagem (AIV), altura de planta na maturidade (APM), acamamento (Ac), valor agronômico (VA), número de ramos (NR), número de vagens por planta (NV), peso de cem sementes (PCS), número de sementes por planta (NS) e produção de grãos (PG). Os dados foram analisados utilizando-se o software Statistica 7.0. Os resultados obtidos possibilitaram a seleção de 77 progênies superiores através da Análise de Componentes Principais. A análise de Agrupamentos, pelo do método de K-means, agregou as progênies em seis grupos de acordo com os caracteres de maior importância em cada um e, através do método de Ward, identificou por meio do dendrograma a estrutura de similaridade e divergência entre as progênies selecionadas. Por fim, comparou-se os métodos de agrupamentos e verificou-se que houve concordância entre ambos quanto aos resultados obtidos
Abstract: The plant breeding is considered to be a complex process that generates multiple information sources and in many cases, difficult to understand. The aim of this work was to select progenies with superior characters from bi-parental crosses with soy source of resistance to glyphosate (RR), and identify intersections and parents more efficient through multivariate approaches. Furthermore, aimed to further test the efficiency of the methods in the selection process for multiple traits of interest. The experiment was conducted in the experimental design of type families to witness progress in the agricultural year 2010/2011 and 2011/2012 in Jaboticabal being that in F3 populations selected six plants were phenotypically superior and evaluated for the traits: number of days to flowering (NDF), number of days to maturity (NDM), height of the first pod (AIV), plant height at maturity (APM), lodging (Ac), agronomic value (VA), number of branches (NR), number of pods per plant (NV), one hundred seed weight (PCS), number of seeds per plant (NS) and grain yield (GY). Data were analyzed using the software Statistica 7.0. The results allowed the selection of 77 superior progenies by Principal Component Analysis. Cluster analysis by the K-means method, all progenies added into six groups according to the characters in each of utmost importance, and by the method of Ward identified by the dendrogram structure similarity and divergence between the progenies. Finally, we compared the clustering methods and found that there was an agreement between them as to the results obtained
Mestre
Vessabutr, Suyanee. "Transfer of chlorsulfuron resistance from tobacco to birdsfoot trefoil (Lotus corniculatus) by asymmetric somatic hybridization." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41010.
Full textMohapatra, Umaballava. "Introduction and expression of transgenes in lettuce (Lactuca sativa L.)." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243641.
Full textReiners, Stephen. "Selectivity of thiobencarb between two lettuce (Lactuca sativa, L.) cultivars /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487329662145846.
Full textCutts, Todd Andrew. "Herbicide resistance enriched hybrid and synthetic seed production and performance in Brassica rapa." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51700.pdf.
Full textSchwarz, Maria. "Exploring the molecular basis of multiple herbicide resistance in black grass (Alopecurus myosuroides)." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12318/.
Full textPuri, Atul. "Biochemical, molecular, and physiological aspects of fluridone herbicide resistance in hydrilla (Hydrilla verticillata)." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013738.
Full textMascanzoni, Elisa. "Epidemiology of herbicide resistance evolution in rice weeds and variability in Echinochloa spp." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3425887.
Full textLa resistenza agli erbicidi è un problema che è cresciuto esponenzialmente negli ultimi 10 anni e riguarda tutte le più importanti colture al mondo. L’Italia è il primo produttore europeo di riso con 230.000 ha localizzati nel nord-ovest della Pianura Padana. Ad oggi 6 infestanti hanno evoluto popolazioni resistenti in riso in Italia, fra queste la più importante è Echinochloa spp. La ricerca si è svolta su due binari paralleli: il primo è uno studio epidemiologico a larga scala sulla principale area riso, il secondo è uno studio sulla classificazione di Echinochloa spp. che comprendente esperimenti di dose risposta su varie specie di Echinochloa spp.agli erbicidi. Obiettivo dello studio epidemiologico era analizzare, a livello comunale, il grado di associazione fra presenza di resistenza e tre importanti predittori agronomici: percentuale di semina in acqua, tessitura del suolo e percentuale di rotazione. Le analisi sono state fatte con più approcci statistici: l’analisi discriminante e la regressione logistica hanno permesso di individuare un alto grado di associazione fra la presenza di resistenza ed i predittori. L’approccio Neural Network ha permesso di calcolare il rischio di evolvere popolazioni resistenti sulla base dei predittori: 70% quando tutte le infestanti resistenti sono state considerate, 30% quando solo i casi di Echinochloa spp. sono stati inclusi, perdendo parte del potere predittivo forse a causa della minore quantità di casi di resistenza inclusi nel database. In Qgis sono state create mappe per illustrare la diffusione dei tre predittori nell’area dello studio e il rischio di evoluzione della resistenza. 20 popolazioni di giavone sono state raccolte nei comuni dove non sono mai stati segnalati casi di resistenza al GIRE ed è stato fatto uno screening. 16 popolazioni sono risultate resistenti ACCase+ALS mostrando che in queste aree la resistenza è presente, ma viene tenuta ad un livello accettabile per gli agricoltori. La seconda parte della ricerca riguardava la classificazione delle diverse specie di giavone, abbinando la classificazione fenotipica alla discriminazione fatta attraverso marcatori molecolari usando il DNA barcoding. 40 accessioni di giavone sono state raccolte da piante singole nel 2015, sono state classificate morfologicamente e testate per la sensibilità al penoxsulam. Fra le piante sensibili, 10 sono state riprodotte per ottenere una quantità maggiore di seme. Lo screening con il penoxsulam è stato ripetuto sulle accessioni riprodotte a confermare la sensibilità. La classificazione morfologica e la discriminazione per marcatori molecolari sono state fatte sia sulle piante originali che sulle riprodotte, dando risultati consistenti: nelle popolazioni riprodotte usando Costea & Tardif (2002) sono presenti solo E. crus-galli ed E. oryzicola, usando Tabacchi et al. (2006) sono presenti E. crus-galli, E. oryzicola ed E. phyllopogon. Sono state analizzate 5 regioni di DNA cloroplastico: matK ha discriminato fra le diverse specie di giavone bianco, oltre a E. crus-galli offrendo un buon match, anche se incompleto, con la classificazione di Tabacchi et al. (2006). Le sequenze di rbcL invece hanno differenziato solo E. oryzicola da E. crus-galli, corrispondendo perfettamente a Costea & Tardif (2002) Un protocollo di PCR specie-specifica è stato impostato su matK gene per discriminare diverse specie di giavoni bianchi in una sola reazione di PCR. Gli esperimenti di dose-risposta sono stati fatti sia in serra che all’aperto su 9 accessioni con 3 erbicidi: cyhalofop – butyl, penoxsulam e florpyrauxifen benzyl: anche se i risultati sono stati variabili, soprattutto nell’esperimento all’aperto, è chiaro che i vari erbicidi hanno efficacia simile su tutte le specie di Echinochloa. I risultati ottenuti dimostrano che pianificare le strategie erbicide sulla base delle diverse specie di Echinochla possa essere erroneo.
Rey, Caballero Jordi. "Unravelling herbicide resistance in corn poppy (Papaver rhoeas L.) to improve integrated weed management strategies." Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/382633.
Full textLa presència de biotips de rosella (Papaver rhoeas L.) resistents a herbicides constitueix un dels principals problemes de moltes àrees cerealistes de secà. La solució del mateix passa per una correcta caracterització de la resistència així com en l'establiment d'una adequada estratègia de maneig integrat. El present treball s'ha plantejat precisament amb aquesta finalitat. Per això a) s'han seleccionat biotips amb resistència múltiple (a inhibidors de la acetolactato sintasa -ALS- i a herbicides auxínics) i biotips únicament resistents a 2,4-D originaris de les zones cerealistes del nord-est peninsular i s’han estudiat les bases moleculars i fisiològiques d'aquestes resistències; b) s'ha volgut discernir sota condicions controlades (hivernacle), si la manca de control observada en camp, mitjançant herbicides inhibidors del fotosistema II (bromoxinil), és deguda a l'estadi fenològic de la mala herba en el moment de l’aplicació o a la presència d' una possible resistència incipient i c) s'han establert diferents estratègies de maneig integrat de rosella en camps comercials de cereals de secà del nord-est peninsular.
The persistence of resistant corn poppy (Papaver rhoeas L.) biotypes is one of the most pressing problems in rainfed Spanish cereal crops. Resolution to this problem begins with the proper characterization of the resistant profile, followed by the establishment of an appropriate integrated management system. The study herein has been conducted precisely towards this end, while maintaining the following bases as a general framework: a) corn poppy biotypes with multiple resistance (acetolactate synthase -ALS- inhibiting herbicides and auxinic herbicides) and only 2,4-D resistance from north-eastern Spain were selected for analysis of molecular and physiological resistance matrices; b) we have tried to investigate under controlled conditions, if failures observed in the field, by photosystem II inhibiting herbicides (bromoxynil), could be directly attributed to the phenological stage of the weed at application time or inherent resistance and c) the creation of integrated management strategies for corn poppy and rainfed cereal fields in North-Eastern Spain.
Ahmed, Amro Mohamed Aly Tawfic. "Control, Assessment and Glyphosate Resistance of Palmer Amaranth(Amaranthus palmeri S. Wats) in Virginia." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/34563.
Full textGlyphosate resistant crops were rapidly adopted by farmers since their introduction in 1996 and currently, greater than 90% of cotton and soybean crops are glyphosate resistant. Glyphosate has been an effective mean for controlling Palmer amaranth, however overreliance on glyphosate based systems resulted in weeds that can no longer be controlled with glyphosate. Palmer amaranth resistance to glyphosate has been confirmed in ten US states including Virginiaâ s bordering neighbor North Carolina. The objectives of this study were to i) determine the spread of Palmer amaranth and evaluate awareness among farmers and agribusinesses of herbicide resistant weeds in Virginia; ii) determine the efficacy of commonly used cotton and soybean herbicides programs for Palmer amaranth control; and iii) conduct greenhouse experiments to quantify the level of glyphosate resistance in a Greensville County, Virginia population. Using a communication network of Virginia county extension agents and crop advisers, Palmer amaranth was found in 15 Virginia counties. A survey was conducted to evaluate awareness of herbicide resistance and management of weeds in Virginia. Ninety percent of producers had fields planted to Roundup Ready® crops for each of the last 3 years. One hundred percent of the responders claimed awareness of the potential for weeds to develop resistance to glyphosate, but when asked about how serious they consider weed resistance to herbicides, the responders average rating was of 7.9 (on a scale of 1 to 10 where 1 is â not at all seriousâ and 10 is â very seriousâ ). Eighteen percent of the responder population claimed no awareness of glyphosate resistant weeds
documented in Virginia. Herbicide efficacy experiments were established in soybean and cotton fields infested with Palmer amaranth. In soybean, experiments were established in a field where Palmer amaranth was not adequately controlled with glyphosate in the previous year. Glyphosate applied at 0.87 + 0.87 + 1.74 kg ae ha-1 at 1, 3, and 5 weeks after planting (WAP) provided 82 to 85% control in 2009, but only 23 to 30% control in 2010, a hot and dry year. Glyphosate applied after preemergence (PRE) herbicides improved control to 90 percent. Programs that included s-metolachlor + metribuzin applied preemergence and followed by glyphosate + fomesafen applied postemergence provided the best control (93%) at 8 WAP. Glufosinate based herbicide programs provided greater than 85% control when applied alone, and control increased to 95% when preceded by PRE herbicides. Many conventional control systems integrating different modes of action provided more than 80% control at final evaluation of Palmer amaranth in 2009 and 2010. In soybean, the most consistent and effective program was flumioxazin applied PRE followed by chlorimuron + thifensulfuron, which provided 99 and 82% control at final evaluation in 2009 and 2010, respectively. Cotton fields were heavily infested with Palmer amaranth, but control with glyphosate had historically been good. Glyphosate applied early postemergence, late postemergence, and late post-directed provided more than 95 percent control at final evaluation of Palmer amaranth. Preemergence applications of fomesafen, fluometuron, or pendimethalin + fomesafen provided 77 to 99 percent early-season control and control was complete with an additional postemergence glyphosate application. Glufosinate applied at 0.45 kg ha-1 at 1 and 3 WAP or applied at 0.45 kg ha-1 following a preemergence herbicide provided greater than 95% control. Greenhouse experiments confirmed Palmer amaranth resistance in a population collected from Greensville County, Virginia. In the first experiment, the resistant biotypeâ s I50 value (rate necessary for 50% inhibition) for dry weight was 1.47 kg ae ha-1, which is 4.6 times greater than the susceptible biotype and 1.7 times the recommended use rate of glyphosate. For fresh weight, the I50 value of the resistant biotype was 1.60 kg ae ha-1, 4.7 times that of the susceptible biotype of 0.34 kg ae ha-1. In the second experiment, the I50 value for the susceptible population could not be determined because all glyphosate rates resulted in complete control. However, the resistant population required 1.01 and 1.30 kg ae ha-1of glyphosate to reduce the fresh and dry weight by 50%.
Master of Science
Bianchi, Leandro 1991. "Efeito de glyphosate e clethodim isolados e em mistura em Digitaria insularis /." Botucatu, 2018. http://hdl.handle.net/11449/153555.
Full textBanca: Leandro Tropaldi
Banca: Lucas Perim
Resumo: Devido ao uso frequente do glyphosate na agricultura, o capim-amargoso (Digitaria insularis) tornou-se uma das plantas daninhas mais problemáticas no Brasil, por adquirir resistência a esse herbicida. Biótipos resistentes em estádios iniciais são facilmente controlados por graminicidas, porém em estádio mais avançado o controle é reduzido. O herbicida clethodim é um graminicida com alta eficiência, portanto, verificar o controle de biótipos resistentes ao glyphosate em diferentes estádios, com o uso isolado de clethodim e em mistura com o glyphosate é fundamental para auxiliar no manejo desta invasora. Assim o presente trabalho teve como objetivo avaliar o desempenho de glyphosate, clethodim e glyphosate + clethodim, em biótipo de D. insularis resistente e suscetível. O ensaio foi realizado em casa de vegetação, inteiramente casualizado, com quatro repetições e repetido em duas épocas do ano. As aplicações foram realizadas em estádio inicial (15 - 20 cm) e em florescimento. Avaliou-se o controle aos 21 dias e o peso da biomassa seca. Para a mistura dos produtos, foi verificada a interação entre os herbicidas: efeito sinérgico, antagônico ou aditivo. No ensaio com plantas em estádio inicial, avaliou-se a concentração de lipídeos na biomassa seca. De forma geral, a aplicação de clethodim aplicado isoladamente controlou o biótipo resistente em estádio inicial, porém em florescimento a eficácia foi reduzida. A mistura mostrou-se eficiente para controle de biótipo resistente em es... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Due to frequent use of glyphosate in agriculture, sourgrass (Digitaria insularis) has become one of the most problematic weeds in Brazil for purchase resistance to this herbicide. Resistant biotypes in initial stages are easily controlled by graminicides, but in a more advanced stage the control is reduced. The herbicide clethodim is a graminicide with high efficiency, therefore, to check the control of resistant biotypes of glyphosate in different stages, with the isolated use of clethodim and in mixture with the glyphosate is fundamental to assist in the management of this weed. Thus the experiment was aimed at evaluate the action of glyphosate, clethodim and glyphosate + clethodim, in a resistant and susceptible biotype of D. insularis. The experiment was carried out in a greenhouse, completely randomized, with four replications and repeated at two times of the year. The applications were performed in the initial stage (15 - 20 cm) and flowering. Plants were evaluated at 21 days after application (DAA) and dry biomass weight. For the mixture of products, the interaction between the herbicides was also verified: synergistic, antagonistic or additive effect. In the experiment with plants at the initial stage, was evaluated the lipid concentration in the dry biomass. In general, the application of clethodim applied alone controlled the resistant biotype at the initial stage, but in flowering the efficiency was reduced. The mixture showed to be efficient for control of resistant biotype in initial and flowering stages. Considering the visual evaluations of control, the interaction between glyphosate and clethodim showed synergic effect for intermediate doses and additive for the highest doses considering the initial stage; in flowered plants, with the additive effects predominating for all as doses, the additive effect prevailed for all doses. For dry mass, the mixture had synergistic interaction ...
Mestre
Massa, Dario [Verfasser], and Roland [Akademischer Betreuer] Gerhards. "Investigations on herbicide resistance in Apera spica-venti populations / Dario Massa. Betreuer: Roland Gerhards." Hohenheim : Kommunikations-, Informations- und Medienzentrum der Universität Hohenheim, 2012. http://d-nb.info/1027352812/34.
Full textStraker, Hannah Elizabeth. "Chemical methods towards the investigation of multiple herbicide resistance in black grass (Alopecurus myosuroides)." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10822/.
Full textNakka, Sridevi. "Physiological, biochemical and molecular characterization of multiple herbicide resistance in Palmer amaranth (Amaranthus palmeri)." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34474.
Full textDepartment of Agronomy
Mithila Jugulam
Palmer amaranth (Amaranthus palmeri) is one of the most aggressive, troublesome and damaging broadleaf weeds in many cropping systems including corn, soybean, cotton, and grain sorghum causing huge yield losses across the USA. As a result of extensive and intensive selection of pre- and -post emergence herbicides, Palmer amaranth has evolved resistance to multiple herbicide modes of action, microtubule-, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS)-, acetolactate synthase (ALS)-, photosystem II (PS II)-, hydroxyphenylpyruvate dioxygenase (HPPD)- and more recently to protoporphyrinogen oxidase (PPO)-inhibitors. A Palmer amaranth population from Kansas was found resistant to HPPD-, PS II-, and ALS-inhibitors. The overall objective of this research was to investigate the target-site and/or non-target-site resistance mechanisms in Palmer amaranth from KS (KSR) to mesotrione (HPPD-inhibitor), atrazine (PS II-inhibitor), and chlorsulfuron (ALS-inhibitor) relative to known susceptible Palmer amaranth from Mississippi (MSS) and KS (KSS). Whole plant dose-response assays showed high level of resistance in KSR to mesotrione, atrazine and chlorsulfuron. KSR was 10-18, 178-237 and >275 fold more resistant to mesotrione, atrazine, and chlorsulfuron, respectively, compared to MSS and KSS. Metabolism studies using [¹⁴C] labeled mesotrione and atrazine demonstrated non-target-site resistance to both herbicides, particularly, enhanced metabolism of [¹⁴C] mesotrione likely mediated by cytochrome P450 monooxygenases and rapid degradation of [¹⁴C] atrazine by glutathione S-transferases (GSTs). In addition, molecular and biochemical basis of mesotrione resistance was characterized by quantitative PCR (qPCR) and immunoblotting. These results showed 4-12 fold increased levels of the HPPD transcript and positively correlated with the increased HPPD protein. Sequencing of atrazine and chlorsulfuron target genes, psbA and ALS, respectively, showed interesting results. The most common mutation (serine264glycine) associated with atrazine resistance in weeds was not found in KSR. On the other hand, a well-known mutation (proline197serine) associated with chlorsulfuron resistance was found in 30% of KSR, suggesting ~70% of plants might have a non-target-site, possibly P450 mediated metabolism based resistance. Over all, KSR evolved both non-target-site and target-site based mechanisms to mesotrione and chlorsulfuron with only non-target-site based mechanism of resistance to atrazine leaving fewer options for weed control, especially in no-till crop production systems. Such multiple herbicide resistant Palmer amaranth populations are a serious threat to sustainable weed management because metabolism-based resistance may confer resistance to other herbicides and even those that are yet to be discovered. The findings of this research are novel and valuable to recommend appropriate weed management strategies in the region and should include diversified tactics to prevent evolution and spread of multiple herbicide resistance in Palmer amaranth.