Desempenho de cultivares de algodão transgênicos (Bt) em relação à ocorrência de pragas
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Data
2017-02-22
Autores
Silva, Roberto da [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A adoção de cultivares de algodão Bt tem crescido nas últimas décadas devido ao aumento da disponibilidade de materiais com novas combinações de proteínas e a ocorrência de espécies de lepidópteros-pragas de difícil controle, como a Helicoverpa armigera. O objetivo deste trabalho foi verificar comparativamente a ocorrência de lepidópteros-pragas e pragas não alvo nas três cultivares Bt atualmente plantadas no Brasil: Bollgard II (Cry1Ac + Cry2Ab2), Widestrike (Cry1Ac + Cry1F) e Twinlink (Cry1Ab + Cry2Ae) e na cultivar não Bt FMT701. Para tanto, foram instalados experimento em campo e casa de vegetação. Experimento I: O delineamento empregado foi blocos casualizados com quatro tratamentos e seis repetições. Foram comparadas três cultivares de algodão Bt: Bollgard II, Widestrik e Twinlink e a cultivar não Bt FMT701. Cada parcela constou de 12 linhas com espaçamento de 0,9m com 30 m de comprimento e densidade de dez plantas/m. As avaliações foram realizadas semanalmente registrando-se a ocorrência de pragas, danos em estruturas reprodutivas e desfolha. Experimento II: Foi desenvolvido em casa de vegetação, utilizando-se as mesmas cultivares do Experimento I. Foram realizadas em cada tratamento infestações artificiais com lagartas de segundo instar da espécie H. armigera obtidas da criação em Laboratório. O delineamento foi inteiramente casualizado, com quatro tratamentos e dez repetições. Cada parcela foi constituída de uma planta de algodão, cultivado em vaso com volume de dez litros. Foram realizadas avaliações diárias registrando-se o número médio de botões florais danificados pelas lagartas e o número de lagartas vivas, até cinco dias após a infestação. Os resultados foram submetidos à análise de variância pelo teste F e as médias foram comparadas pelo teste de Tukey (5%). Cultivares de algodão Bt Bollgard II (Cry1Ac + Cry2Ab2), Widestrike (Cry1Ac + Cry1F) e Twinlink (Cry1Ab + Cry2Ae) foram eficientes na proteção de plantas contra o ataque de Alabama argillacea, Chrysodeixis includens, Spodoptera eridania e Pectinophora gossypiella e afetaram negativamente a população de Spodoptera frugiperda e H. armigera, porém a cultivar Widestrike não proporcionou alto desempenho na proteção de plantas contra o ataque destas espécies. Cultivares de algodão Bt Bollgard II, Widestrike e Twinlink proporcionaram maior produtividade de algodão em caroço que a cultivar não Bt (FMT701), com destaque para a cultivar Widestrike que alcançou a maior produtividade. Cultivares de algodão Bt Bollgard II, Widestrike e Twinlink foram eficientes na proteção as plantas contra o ataque de H. armigera em condições de casa de vegetação.
The adoption of Bt cotton cultivars increased in the last harvest, due to the increased availability of cultivars with new protein combinations and the occurrence of lepidopteran pests such as Helicoverpa armigera. The objective of this work was to verify comparatively the occurrence of lepidopteran pests and non-target pests of the Bt technology in three Bt cultivars currently planted in Brazil: Bolgard II (Cry1Ac + Cry2Ab2), Widestrike (Cry1Ac + Cry1F) and Twinlink (Cry1Ab + Cry2Ae) and non-Bt cultivar FMT701. Experiment I: The design was randomized blocks with four treatments and six replicates. Each plot consisted of 12 rows with spacing of 0.9 m, 30 m of length and density of 10 plants/m. The evaluations were carried out weekly, registering the occurrence of pests, damage to reproductive structures and defoliation. Experiment II: It was conducted in a greenhouse, using the same cultivars of Experiment I. In each treatment were made artificial infestations with H. armigera caterpillars obtained from the creation in Laboratory. The design was completely randomized, with four treatments and 10 replications, for each species of caterpillars. Each plot consisted of a cotton plant grown in a ten-liter pot. Daily evaluations were carried out, registering the number of floral buds damaged by caterpillars and the number of alive caterpillars, until five days after infestation. The results were submitted to analysis of variance by the F test and the means were compared by the Tukey Test (5%). Bollgard II, Widestrike and Twinlink cotton cultivars were efficient in protecting plants against the attack of Alabama argillacea, Chrysodeixis includens, Spodoptera eridania and Pectinophora gossypiella and negatively affected the population of Spodoptera frugiperda and H. armigera, but the Widestrike cultivar is not of high performance in the protection of plants against the attack of these species. Cotton Bt cultivars Bollgard II, Widestrike and Twinlink provided higher productivity than the non-Bt cultivar FMT701, especially the Widestrike cultivar, which achieved the highest productivity. Cotton cultivars Bt Bollgard II, Widestrike and Twinlink were efficient in protecting the plants against H. armigera attack under greenhouse conditions.
The adoption of Bt cotton cultivars increased in the last harvest, due to the increased availability of cultivars with new protein combinations and the occurrence of lepidopteran pests such as Helicoverpa armigera. The objective of this work was to verify comparatively the occurrence of lepidopteran pests and non-target pests of the Bt technology in three Bt cultivars currently planted in Brazil: Bolgard II (Cry1Ac + Cry2Ab2), Widestrike (Cry1Ac + Cry1F) and Twinlink (Cry1Ab + Cry2Ae) and non-Bt cultivar FMT701. Experiment I: The design was randomized blocks with four treatments and six replicates. Each plot consisted of 12 rows with spacing of 0.9 m, 30 m of length and density of 10 plants/m. The evaluations were carried out weekly, registering the occurrence of pests, damage to reproductive structures and defoliation. Experiment II: It was conducted in a greenhouse, using the same cultivars of Experiment I. In each treatment were made artificial infestations with H. armigera caterpillars obtained from the creation in Laboratory. The design was completely randomized, with four treatments and 10 replications, for each species of caterpillars. Each plot consisted of a cotton plant grown in a ten-liter pot. Daily evaluations were carried out, registering the number of floral buds damaged by caterpillars and the number of alive caterpillars, until five days after infestation. The results were submitted to analysis of variance by the F test and the means were compared by the Tukey Test (5%). Bollgard II, Widestrike and Twinlink cotton cultivars were efficient in protecting plants against the attack of Alabama argillacea, Chrysodeixis includens, Spodoptera eridania and Pectinophora gossypiella and negatively affected the population of Spodoptera frugiperda and H. armigera, but the Widestrike cultivar is not of high performance in the protection of plants against the attack of these species. Cotton Bt cultivars Bollgard II, Widestrike and Twinlink provided higher productivity than the non-Bt cultivar FMT701, especially the Widestrike cultivar, which achieved the highest productivity. Cotton cultivars Bt Bollgard II, Widestrike and Twinlink were efficient in protecting the plants against H. armigera attack under greenhouse conditions.
Descrição
Palavras-chave
Gossypium hirsutum, Manejo integrado de pragas, Lepidópteros-pragas, Integrated pest management, Lepidoptera-pests