Resposta de genótipos de soja ao ataque de Euschistus heros (Hemiptera: Pentatomidae)
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Data
2020-02-28
Autores
Victor, Vinícius Suárez
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Universidade Estadual Paulista (Unesp)
Resumo
A soja, [Glycine max (L.) (Merrill)] é um dos principais grãos produzidos mundialmente, com o Brasil apresentando grande destaque em produtividade e exportação. Diversos fatores podem comprometer a produção desta leguminosa, no qual o ataque de insetos fitófagos possui grande relevância. Dentre os insetos-praga para a cultura da soja, Euschistus heros (Fabricius) possui grande importância pela alta incidência no campo e elevado danos ocasionados. Como alternativa à baixa eficiência dos métodos de controle e aplicações indevidas de defensivos químicos, este trabalho procurou avaliar a tolerância de quatro genótipos de soja frente ao ataque de E. heros (3 percevejos/planta) em diferentes fases fenológicas (R3, R5, R7, R3 até o final do ciclo e controle) a campo em duas safras, e respostas enzimáticas, analisadas em laboratório, após o ataque de E. heros em casa de vegetação durante a fase fenológica R5 por diferentes períodos de infestação (7, 14, 21 dias). Para isto, foi avaliado a campo a produtividade, peso de 100 grãos, número de vagens/ 10 plantas, número de grãos/10 plantas, retenção foliar e nível de danos ocasionados. Em casa de vegetação avaliou-se produtividade da linha central, número de vagens e número de grãos. Posteriormente, em análises químicas realizadas em laboratório, foram avaliadas as atividades das enzimas peroxidase, polifenol oxidase, catalase, superóxido dismutase e proteínas totais solúveis. Os genótipos ‘Conquista’ infestado em R3, ‘IAC 100’ infestado em R5 e R7 apresentaram resultados satisfatórios quanto à produtividade e peso de 100 grãos. Além disso ‘IAC-100’, para as mesmas fases fenológicas, apresentou bons resultados quanto ao número médio de vagens e número médio de grãos, confirmando sua tolerância ao ataque de E. heros. Em relação aos danos e retenção foliar nenhum genótipo apresentou resultados satisfatórios. Para as análises das enzimas oxidativas, a atividade de peroxidase demonstrou resultado satisfatório para o genótipo ‘IAC-100’ após 7, 14 e 21 dias de infestação, o que proporcionou alta produtividade, produção de vagens e grãos, sugerindo ser uma das causas de tolerância de ‘IAC-100’ para E. heros. As demais enzimas oxidativas aparentemente não demonstraram efeitos de tolerância ao ataque de E. heros.
The soybean, [Glycine max (L.) (Merrill)] is one of the main grains produced worldwide, with Brazil showing great prominence in productivity and exports. Several factors can compromise the production of this legume, in which the attack of phytophagous insects has great relevance. Among the pest insects for soybean, Euschistus heros is of great importance due to the high incidence in the field and high damage caused. As an alternative to the low efficiency of control methods and improper applications of chemical pesticides, this work sought to evaluate the tolerance of four soybean genotypes, against the attack of E. heros (3 stinkbugs / plant) in different phenological phases (R3, R5, R7 , R3 until the end of the cycle and control) in the field in two harvests, and enzymatic responses, analyzed in the laboratory, after the attack of E. heros in the greenhouse during the phenological phase R5 by different periods of infestation (7, 14, 21 days). For this, productivity, weight of 100 grains, number of pods, number of grains, leaf retention and level of damage caused were evaluated in the field. In the greenhouse, productivity, number of pods and number of grains were evaluated. Subsequently, in chemical analyzes performed in the laboratory, the activities of the enzymes peroxidase, polyphenol oxidase, catalase, superoxide dismutase and total soluble proteins were evaluated. The genotypes 'Conquista' infested in R3, 'IAC 100' infested in R5 and R7 showed satisfactory results in terms of productivity and weight of 100 grains. In addition, ‘IAC-100’, for the same phenological phases, showed good results regarding the average number of pods and average number of grains, confirming its tolerance to the attack of E. heros. Regarding damage and leaf retention, no genotype showed satisfactory results. For the analysis of oxidative enzymes, the peroxidase activity demonstrated a satisfactory result for the 'IAC-100' genotype after 7, 14 and 21 days of infestation, which provided high productivity, production of pods and grains, suggesting that it is one of the causes of tolerance for 'IAC-100' for E. heros. The other oxidative enzymes apparently did not show effects of tolerance to the attack of E. heros.
The soybean, [Glycine max (L.) (Merrill)] is one of the main grains produced worldwide, with Brazil showing great prominence in productivity and exports. Several factors can compromise the production of this legume, in which the attack of phytophagous insects has great relevance. Among the pest insects for soybean, Euschistus heros is of great importance due to the high incidence in the field and high damage caused. As an alternative to the low efficiency of control methods and improper applications of chemical pesticides, this work sought to evaluate the tolerance of four soybean genotypes, against the attack of E. heros (3 stinkbugs / plant) in different phenological phases (R3, R5, R7 , R3 until the end of the cycle and control) in the field in two harvests, and enzymatic responses, analyzed in the laboratory, after the attack of E. heros in the greenhouse during the phenological phase R5 by different periods of infestation (7, 14, 21 days). For this, productivity, weight of 100 grains, number of pods, number of grains, leaf retention and level of damage caused were evaluated in the field. In the greenhouse, productivity, number of pods and number of grains were evaluated. Subsequently, in chemical analyzes performed in the laboratory, the activities of the enzymes peroxidase, polyphenol oxidase, catalase, superoxide dismutase and total soluble proteins were evaluated. The genotypes 'Conquista' infested in R3, 'IAC 100' infested in R5 and R7 showed satisfactory results in terms of productivity and weight of 100 grains. In addition, ‘IAC-100’, for the same phenological phases, showed good results regarding the average number of pods and average number of grains, confirming its tolerance to the attack of E. heros. Regarding damage and leaf retention, no genotype showed satisfactory results. For the analysis of oxidative enzymes, the peroxidase activity demonstrated a satisfactory result for the 'IAC-100' genotype after 7, 14 and 21 days of infestation, which provided high productivity, production of pods and grains, suggesting that it is one of the causes of tolerance for 'IAC-100' for E. heros. The other oxidative enzymes apparently did not show effects of tolerance to the attack of E. heros.
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Palavras-chave
Glycine max (L.), Resistência de plantas a insetos, Tolerância, MIP, Host plant resistance, Brown stink bug, Tolerance