Resistência de espécies silvestres de amendoim (Arachis spp.) ao ataque de Enneothrips flavens Moulton, 1941 (Thysanoptera: Thripidae) e Stegasta bosquella (Chambers, 1875) (Lepidoptera: Gelechiidae)
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Data
2009-07-24
Autores
Janini, Júlio César [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O amendoim (Arachis hypogaea L.) é uma cultura em crescimento no Brasil, e a sua produção atual é de cerca de 300.000 toneladas/ano, numa área de plantio de mais de 115.200 hectares. Entretanto, a rentabilidade do produtor é limitada pela ocorrência de pragas e doenças, e o seu controle químico eleva o custo de produção. Entre as diversas pragas que atacam a cultura, as mais importantes no Brasil são o tripes (Enneothrips flavens Moulton, 1941 - Thysanoptera: Thripidae) e a lagarta do pescoço vermelho Stegasta bosquella (Chambers, 1875) - Lepidoptera: Gelechiidae). Não se conhecem variedades resistentes, mas o germoplasma do gênero Arachis, nativo da América do Sul, pode conter genes de resistência, ainda não explorados. Assim, este trabalho foi realizado visando avaliar o germoplasma silvestre disponível em coleção, e identificar possíveis fontes de resistência. Dois experimentos de campo foram conduzidos no município de Pindorama, SP. O primeiro envolveu quarenta e quatro acessos de espécies silvestres e dois anfidiploides híbridos de espécies silvestres, além de dois cultivares hypogaea conhecidos, usados como controles. As sementes foram inicialmente germinadas em casa de vegetação e, as plântulas transplantadas no campo. O delineamento experimental adotado foi o de blocos ao acaso com quatro repetições. Iniciando aos 30 dias após o plantio das mudas no campo, foram feitas amostragens de folíolos a cada 15 dias, num total de cinco avaliações. Anotaram-se: porcentagem de folíolos ainda fechados, com presença de tripes-do-prateamento e lagarta-do-pescoço-vermelho; notas dos sintomas de danos visuais de tripes e da lagarta, em folíolos recém abertos baseando-se numa escala de notas de 1 a 5. Outro experimento foi conduzido no campo, envolvendo 35 acessos de espécie silvestres, dois anfidiplóides e dois cultivares controles. O delineamento experimental...
The peanut (Arachis hypogaea L.) is a crop of increasing importance in Brazil, and its present production is around 300,000 tons/year, over a planting area of more than 115,200 hectares. However, peanut grower profitability is limited by the occurrence of pests and diseases, whose chemical control raises costs of production. Among the pests known to affect the peanut crop, the most important in Brazil are the tripes (Enneothrips flavens) and the redneck worm (Stegasta bosquella). Resistant varieties are not known, but the germplasm of Arachis, native of South America, may contain genes of resistance, yet not explored. And so, this work was done to evaluate wild peanut collected germplasm, so as to identify possible sources of resistance. Two field experiments were carried out at Pindorama – SP. The first involved forty four wild Arachis accessions, two hybrid anfidiploids, obtained from crossings between species, and two A. hypogaea known cultivars, as the controls. Seeds were initially germinated in greenhouse conditions and, then, transplanted to the field. The field experiment consisted of a complete ramdomized block design with four replications. Starting at 30 days after plantlets were transplanted, samplings of leaflets were done at 15 day intervals, comprising five evaluations along the plant cycle. The following data were obtained: percentage of closed leaflets that showed the presence of thrips and/or redneck worm; damage ratings of thrips and redneckworm from recently opened leaves, using a scale of 1 to 5. Another experiment was conducted, and this involved thirty five wild accessions, two anfidiploids and two control cultivars. The experimental design and the insect evaluations followed the same criteria of the previous experiment. In this case, the following data were additionally collected, from treated (sprayed for pest control) and untreated plots: number and length... (Complete abstract click electronic access below)
The peanut (Arachis hypogaea L.) is a crop of increasing importance in Brazil, and its present production is around 300,000 tons/year, over a planting area of more than 115,200 hectares. However, peanut grower profitability is limited by the occurrence of pests and diseases, whose chemical control raises costs of production. Among the pests known to affect the peanut crop, the most important in Brazil are the tripes (Enneothrips flavens) and the redneck worm (Stegasta bosquella). Resistant varieties are not known, but the germplasm of Arachis, native of South America, may contain genes of resistance, yet not explored. And so, this work was done to evaluate wild peanut collected germplasm, so as to identify possible sources of resistance. Two field experiments were carried out at Pindorama – SP. The first involved forty four wild Arachis accessions, two hybrid anfidiploids, obtained from crossings between species, and two A. hypogaea known cultivars, as the controls. Seeds were initially germinated in greenhouse conditions and, then, transplanted to the field. The field experiment consisted of a complete ramdomized block design with four replications. Starting at 30 days after plantlets were transplanted, samplings of leaflets were done at 15 day intervals, comprising five evaluations along the plant cycle. The following data were obtained: percentage of closed leaflets that showed the presence of thrips and/or redneck worm; damage ratings of thrips and redneckworm from recently opened leaves, using a scale of 1 to 5. Another experiment was conducted, and this involved thirty five wild accessions, two anfidiploids and two control cultivars. The experimental design and the insect evaluations followed the same criteria of the previous experiment. In this case, the following data were additionally collected, from treated (sprayed for pest control) and untreated plots: number and length... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Amendoim, Plantas - Resistencia, Pragas agricolas, Enneothrips flavens, Stegasta bosquella, Peanuts, Plant resistance
Como citar
JANINI, Júlio César. Resistência de espécies silvestres de amendoim (Arachis spp.) ao ataque de Enneothrips flavens Moulton, 1941 (Thysanoptera: Thripidae) e Stegasta bosquella (Chambers, 1875) (Lepidoptera: Gelechiidae). 2009. xiii, 89 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2009.