Ação do herbicida glyphosate em biótipos de Digitaria insularis resistentes e suscetíveis
Carregando...
Arquivos
Data
2017-07-25
Autores
Gazola, Tiago [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
As infestações com Digitaria insularis em áreas de culturas anuais e os casos de resistência ao herbicida glyphosate aumentaram nos últimos anos, e estes fatos contribuíram para tornar a espécie uma das mais importantes plantas daninhas do Brasil. Diante disso, foram desenvolvidos experimentos que tiveram como objetivo confirmar a resistência de biótipos de D. insularis perenizados e propagados vegetativamente resistentes ao glyphosate, bem como, compreender o perfil metabólico do herbicida nestas plantas, verificar se existe alteração no controle relativo em função dos métodos de propagação empregados e determinar o fator de resistência nas progênies obtidas por sementes autofecundadas. Foram realizados três experimentos em casa de vegetação no delineamento inteiramente casualizado, sendo os dois primeiros com oito biótipos de capim-amargoso considerados como suscetíveis e três com suspeita de resistência ao herbicida glyphosate. No primeiro experimento foi avaliado o controle das plantas aos 7, 14, 21 e 28 dias após a aplicação (DAA) do glyphosate. No segundo experimento, avaliou-se o controle nas mesmas épocas do primeiro e 72 horas após a aplicação do herbicida foi quantificado o acúmulo de ácido chiquímico e ácido quínico, deposição, absorção e translocação de glyphosate, concentração de AMPA, dos aminoácidos aromáticos (fenilalanina, tirosina e triptofano) e ácido salicílico. No terceiro experimento foram conduzidas curvas de dose-resposta com glyphosate nas doses de 0; 90; 180; 360; 720; 1440; 2880 e 5760 g e.a. ha-1, na progênie de quatro biótipos, e foram avaliados o controle e a massa seca aos 21 DAA para obtenção do fator de resistência. O método de propagação vegetativa se mostrou consistente e não alterou a resposta dos biótipos nos testes de fitointoxicação por glyphosate. Confirmou-se a resistência dos três biótipos pelo controle visual e acúmulo de ácido chiquímico e quínico. A metabolização em AMPA não é considerada mecanismo de resistência da espécie ao glyphosate. Os biótipos resistentes apresentaram maior concentração de ácido salicílico. As progênies obtidas por autofecundação apresentaram fator de resistência para EC50 de 14,37 e 7,04 e para GR50 12,79 e 3,77.
Digitaria insularis ocurrence infestations in annual crop and cases of glyphosate herbicide resistance have increased in recent years, and the facts contributed to make the species one of the most important weeds in Brazil. Therefore, experiments were carried out to confirm the resistance of perennial and vegetatively propagated D. insularis biotypes resistant to glyphosate, as well as to understand the metabolic profile of the herbicide in these plants, to verify if there is alteration in the relative control according to the methods and determine the resistance factor in the progenies obtained by self-fertilized seeds. Three experiments were carried out under greenhouse conditions in a completely randomized design, the first two with eight sourgrass biotypes considered as susceptible and three with suspected resistance to glyphosate herbicide. In the first experiment, the control of the plants at 7, 14, 21 and 28 days after glyphosate application (DAA) was evaluated. In the second experiment, the control was evaluated in the same periods of the first and 72 hours after the application of the herbicide was quantified the accumulation of shiquimic acid and quinic acid, deposition, absorption and translocation of glyphosate, concentration of AMPA, aromatic amino acids (phenylalanine, tyrosine and tryptophan) and salicylic acid. In the third experiment, dose-response curves were conducted with glyphosate at doses of 0; 90; 180; 360; 720; 1440; 2880 and 5760 g e.a. ha-1 , in the progeny of four biotypes, and control and dry mass were evaluated at 21 DAA to obtain the resistance factor. The vegetative propagation method was consistent and did not alter the response of the biotypes in the glyphosate control tests. The resistance of the three biotypes was confirmed by the visual control and accumulation of shikimic and quinic acid. Metabolization in AMPA is not considered a resistance mechanism of the species to glyphosate. Resistant biotypes showed higher concentration of salicylic acid. The progenies obtained by self-fertilization presented a resistance factor for EC50 of 14,37 and 7,04 and for GR50 12,79 and 3,77.
Digitaria insularis ocurrence infestations in annual crop and cases of glyphosate herbicide resistance have increased in recent years, and the facts contributed to make the species one of the most important weeds in Brazil. Therefore, experiments were carried out to confirm the resistance of perennial and vegetatively propagated D. insularis biotypes resistant to glyphosate, as well as to understand the metabolic profile of the herbicide in these plants, to verify if there is alteration in the relative control according to the methods and determine the resistance factor in the progenies obtained by self-fertilized seeds. Three experiments were carried out under greenhouse conditions in a completely randomized design, the first two with eight sourgrass biotypes considered as susceptible and three with suspected resistance to glyphosate herbicide. In the first experiment, the control of the plants at 7, 14, 21 and 28 days after glyphosate application (DAA) was evaluated. In the second experiment, the control was evaluated in the same periods of the first and 72 hours after the application of the herbicide was quantified the accumulation of shiquimic acid and quinic acid, deposition, absorption and translocation of glyphosate, concentration of AMPA, aromatic amino acids (phenylalanine, tyrosine and tryptophan) and salicylic acid. In the third experiment, dose-response curves were conducted with glyphosate at doses of 0; 90; 180; 360; 720; 1440; 2880 and 5760 g e.a. ha-1 , in the progeny of four biotypes, and control and dry mass were evaluated at 21 DAA to obtain the resistance factor. The vegetative propagation method was consistent and did not alter the response of the biotypes in the glyphosate control tests. The resistance of the three biotypes was confirmed by the visual control and accumulation of shikimic and quinic acid. Metabolization in AMPA is not considered a resistance mechanism of the species to glyphosate. Resistant biotypes showed higher concentration of salicylic acid. The progenies obtained by self-fertilization presented a resistance factor for EC50 of 14,37 and 7,04 and for GR50 12,79 and 3,77.
Descrição
Palavras-chave
Ácido chiquímico, Ácido aminometilfosfônico, Capim-amargoso, Resistência a herbicidas, Shiquimic acid, Aminomethylphosphonic acid, Sourgrass, Resistance to herbicides