Seleção de genótipos de arroz à Glyphepomis spinosa (Hemiptera: Pentatomidae) pelas categorias de resistência e associação do comportamento alimentar com Electrical Penetration Graph (EPG)
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Data
2021-11-03
Autores
Silva, Franciele Cristina da
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Universidade Estadual Paulista (Unesp)
Resumo
A espécie Glyphepomis spinosa Campos & Grazia (Hemiptera: Pentatomidae) está presente nos cultivos de arroz irrigado e sequeiro. A resistência de plantas a insetos pode trazer contribuições significativas para o manejo da espécie. Os objetivos deste estudo, foram identificar genótipos de arroz resistente a G. spinosa, estabelecer uma metodologia de pesquisa em estudo de resistência de plantas a percevejos através da técnica do Electrical Penetration Graph (EPG) e caracterizar o comportamento alimentar em plantas de arroz com diferentes níveis de resistência. Quinze genótipos de arroz foram utilizados para avaliação de antixenose, antibiose e tolerância. Foram realizados testes com e sem chance de escolha para os ensaios de antixenose para alimentação e oviposição, complementando com mensuração de cor e dureza do colmo. Avaliou-se variáveis de desenvolvimento biológico e reprodutivo dos insetos nos ensaios de antibiose. No ensaio de tolerância avaliou-se os atributos morfológicos (número de folhas, altura, número de perfilhos, número de perfilhos atacados, número de perfilhos com “coração morto”, massa seca da parte aérea e massa seca do sistema radicular) das plantas previamente infestadas por um casal de percevejos e plantas sem infestação (testemunha), e propôs uma escala de nota de injúrias. Utilizando a técnica do EPG, avaliou-se três fases de desenvolvimento da espécie (fêmea adulta, macho adulto, ninfas de 5° instar e ninfas de 3° instar) para verificar qual a mais adequada para estudos com resistência de plantas. Com base nos resultados dos demais ensaios e histórico de resistência para outras espécies de insetos sugadores, foram selecionados quatro genótipos de arroz (Canela de Ferro, BRS Esmeralda, Primavera e Xingu), com diferentes níveis de resistência para estudar o comportamento alimentar de fêmeas de G. spinosa. Os genótipos menos atrativos pelo aos insetos e que possuem maior dureza de tecido foram Primavera, BRS Esmeralda, BRS Pepita, Canela de Ferro, Guarani e Nenenzinho e os genótipos menos preferidos para oviposição foram Canela de Ferro, BRS Esmeralda e Guarani. Os genótipos Canela de Ferro, Bacaba Branco, Bico Ganga, Nenenzinho, Miúdo Branco e Lageado Ligeiro afetaram negativamente o desenvolvimento dos insetos de G. spinosa. Os genótipos Bonança e Primavera possuem traços que evidenciam presença de tolerância. A fase de desenvolvimento que mais realiza sondagens são fêmeas, seguida pelos machos. Estudando o comportamento alimentar da espécie em genótipos com diferentes níveis de resistência foram verificados 6 tipos/subtipos de formas de ondas, semelhantes às verificadas para a espécie Tibraca limbativentris Stal (Hemiptera: Pentatomidae). A espécie utiliza duas estratégias para se alimentar dos colmos de arroz: bainha salivar e ruptura celular (laceração e maceração). O tempo de sondagem foi maior nos genótipos que possuem resistência e menor no genótipo suscetível, tendo alongado o tempo de primeira prova para os genótipos Canela de Ferro e BRS Esmeralda. Com os resultados obtidos neste estudo, espera-se contribuir para melhor entendimento dos mecanismos de defesa em arroz a insetos sugadores, além de melhor compreensão da relação inseto-hospedeiro, e fornecer recursos para desenvolver técnicas de controle satisfatórias, fornecendo metodologia específica para trabalhos futuros envolvendo resistência de plantas a percevejos e técnica do EPG, que poderão colaborar para o Manejo Integrado de Pragas na cultura do arroz.
The species Glyphepomis spinosa Campos & Grazia (Hemiptera: Pentatomidae) is present in irrigated and upland rice crops. Plant resistance to insects can make significant contributions to the management of the species. The objectives of this study were to identify rice genotypes resistant to G. spinosa, to establish a research methodology in the study of plant resistance to bed bugs using the Electrical Penetration Graph (EPG) technique and to characterize the feeding behavior of rice plants with different resistance levels. Fifteen rice genotypes were used to assess antixenosis, antibiosis and tolerance. Choice and no-choice tests were carried out for the antixenosis tests for feeding and oviposition, complementing with measurement of color and hardness of the stalk. Variables of biological and reproductive development of insects were evaluated in antibiosis assays. In the tolerance test, the morphological attributes (number of leaves, height, number of tillers, number of attacked tillers, number of tillers with "dead heart", dry mass of aerial part and dry mass of root system) of previously plants were evaluated infested by a couple of bugs and plants without infestation (witness), and proposed an injury rating scale. Using the EPG technique, three stages of development of the species were evaluated (adult female, adult male, 5th instar nymphs and 3rd instar nymphs) to verify which is the most suitable for studies on plant resistance. Based on the results of the other tests and history of resistance to other species of sucking insects, four rice genotypes (Canela de Ferro, BRS Esmeralda, Primavera and Xingu) with different levels of resistance were selected to study the feeding behavior of females G. spinosa. The genotypes less attractive to insects and with greater tissue hardness were Primavera, BRS Esmeralda, BRS Pepita, Canela de Ferro, Guarani and Nenenzinho and the least preferred genotypes for oviposition were Canela de Ferro, BRS Esmeralda and Guarani. The genotypes Canela de Ferro, Bacaba Branco, Bico Ganga, Nenenzinho, Miúdo Branco and Lageado Ligeiro negatively affected the development of G. spinosa insects. The Bonança and Primavera genotypes have traits that show the presence of tolerance. The developmental stage that most probes are females, followed by males. Studying the feeding behavior of the species in genotypes with different levels of resistance, 6 types/subtypes of waveforms were verified, similar to those verified for the species Tibraca limbativentris Stal (Hemiptera: Pentatomidae). The species uses two strategies to feed on rice stalks: salivary sheath and cell rupture (laceration and maceration). The probing time was longer in the resistant genotypes and shorter in the susceptible genotype, having lengthened the first test time for the Canela de Ferro and BRS Esmeralda genotypes. With the results obtained in this study, it is expected to contribute to a better understanding of the defense mechanisms in rice against sucking insects, in addition to a better understanding of the insect-host relationship, and provide resources to develop satisfactory control techniques, providing specific methodology for future work involving plant resistance to stink bugs and the EPG technique, which could contribute to Integrated Pest Management in rice cultivation.
The species Glyphepomis spinosa Campos & Grazia (Hemiptera: Pentatomidae) is present in irrigated and upland rice crops. Plant resistance to insects can make significant contributions to the management of the species. The objectives of this study were to identify rice genotypes resistant to G. spinosa, to establish a research methodology in the study of plant resistance to bed bugs using the Electrical Penetration Graph (EPG) technique and to characterize the feeding behavior of rice plants with different resistance levels. Fifteen rice genotypes were used to assess antixenosis, antibiosis and tolerance. Choice and no-choice tests were carried out for the antixenosis tests for feeding and oviposition, complementing with measurement of color and hardness of the stalk. Variables of biological and reproductive development of insects were evaluated in antibiosis assays. In the tolerance test, the morphological attributes (number of leaves, height, number of tillers, number of attacked tillers, number of tillers with "dead heart", dry mass of aerial part and dry mass of root system) of previously plants were evaluated infested by a couple of bugs and plants without infestation (witness), and proposed an injury rating scale. Using the EPG technique, three stages of development of the species were evaluated (adult female, adult male, 5th instar nymphs and 3rd instar nymphs) to verify which is the most suitable for studies on plant resistance. Based on the results of the other tests and history of resistance to other species of sucking insects, four rice genotypes (Canela de Ferro, BRS Esmeralda, Primavera and Xingu) with different levels of resistance were selected to study the feeding behavior of females G. spinosa. The genotypes less attractive to insects and with greater tissue hardness were Primavera, BRS Esmeralda, BRS Pepita, Canela de Ferro, Guarani and Nenenzinho and the least preferred genotypes for oviposition were Canela de Ferro, BRS Esmeralda and Guarani. The genotypes Canela de Ferro, Bacaba Branco, Bico Ganga, Nenenzinho, Miúdo Branco and Lageado Ligeiro negatively affected the development of G. spinosa insects. The Bonança and Primavera genotypes have traits that show the presence of tolerance. The developmental stage that most probes are females, followed by males. Studying the feeding behavior of the species in genotypes with different levels of resistance, 6 types/subtypes of waveforms were verified, similar to those verified for the species Tibraca limbativentris Stal (Hemiptera: Pentatomidae). The species uses two strategies to feed on rice stalks: salivary sheath and cell rupture (laceration and maceration). The probing time was longer in the resistant genotypes and shorter in the susceptible genotype, having lengthened the first test time for the Canela de Ferro and BRS Esmeralda genotypes. With the results obtained in this study, it is expected to contribute to a better understanding of the defense mechanisms in rice against sucking insects, in addition to a better understanding of the insect-host relationship, and provide resources to develop satisfactory control techniques, providing specific methodology for future work involving plant resistance to stink bugs and the EPG technique, which could contribute to Integrated Pest Management in rice cultivation.
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Percevejos, Oryza sativa, Biotecnologia