Resistência de genótipos de feijoeiro a Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae)
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Data
2010-12-01
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Editora da Universidade Federal de Lavras (UFLA)
Resumo
Durante o armazenamento de grãos de feijão (Phaseolus vulgaris L.), o rendimento pode ser reduzido devido às infestações de carunchos como os da espécie Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae). O ataque desse inseto afeta diretamente a qualidade dos grãos, além de facilitar a entrada de patógenos, tornando-os inviáveis para o consumo e/o comércio. Com a finalidade de buscar uma estratégia alternativa para o controle deste caruncho, avaliou-se a possível resistência de linhagens quase isogênicas contendo arcelina, linhagens selvagens contendo arcelina e cultivares comerciais de feijoeiro, em laboratório (T= 25±2° C, U.R.= 70±10% e fotoperíodo= 12h). Foram utilizados frascos contendo 10 g de grãos dos genótipos, os quais foram infestados por uma semana com sete casais do caruncho. Vinte e um dias após a infestação, os grãos foram avaliados contando-se o número de ovos viáveis. A partir de 25 dias da infestação, os grãos foram observados diariamente avaliando-se o número e o peso dos insetos emergidos, a viabilidade larval, o ciclo biológico (ovo-adulto) e o peso de grãos consumidos. Empregou-se um delineamento inteiramente casualizado, com oito repetições. Os genótipos Arc.2, Arc.3, Arc.4, Arc.3S e Ipa 6 expressaram baixos níveis de não-preferência para oviposição e foram classificados como deterrentes. Os genótipos Arc.1S e Arc.1 expressaram elevados níveis de antibiose; Arc.2, Arc.3 e Arc.4 apresentam o mesmo mecanismo, porém, em níveis inferiores.
During the storage of bean grains (Phaseolus vulgaris L.), production may be reduced due to weevils attack such as the species Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae). This insect attack affects directly the quality of grain and facilitates the entry of pathogens, making them impractical for consumption and trade. In order to find an alternative strategy to control of this pest, we assessed the possible resistance of near isogenic lines containing arcelin, wild lines containing arcelin and cultivars, in laboratory (T= 25±2° C, R.H.= 70±10% and photoperiod= 12h). The assays were conducted in vials containing 10g of bean grains per genotype, releasing seven pairs of the insect and maintaining the infestation during one week. Twenty-one days after the releasing, the grains were evaluated counting the viable eggs. Twenty-five days after the infestation, the evalutions were daily initiated, observing the number of adults emerged, larvae viability, development period (egg to adult) and weight of grains consumed. The assays were performed in a completely randomized design with eight replicates. The genotypes Arc.2, Arc.3, Arc.4, Arc.3S and Ipa 6 showed low levels of oviposition non-preference, being classified as deterrents. The genotypes Arc.1S and Arc.1 expressed high levels of antibiosis; Arc.2, Arc.3 and Arc.4 showed the same mechanism, however in lower levels.
During the storage of bean grains (Phaseolus vulgaris L.), production may be reduced due to weevils attack such as the species Zabrotes subfasciatus (Bohemann, 1833) (Coleoptera: Bruchidae). This insect attack affects directly the quality of grain and facilitates the entry of pathogens, making them impractical for consumption and trade. In order to find an alternative strategy to control of this pest, we assessed the possible resistance of near isogenic lines containing arcelin, wild lines containing arcelin and cultivars, in laboratory (T= 25±2° C, R.H.= 70±10% and photoperiod= 12h). The assays were conducted in vials containing 10g of bean grains per genotype, releasing seven pairs of the insect and maintaining the infestation during one week. Twenty-one days after the releasing, the grains were evaluated counting the viable eggs. Twenty-five days after the infestation, the evalutions were daily initiated, observing the number of adults emerged, larvae viability, development period (egg to adult) and weight of grains consumed. The assays were performed in a completely randomized design with eight replicates. The genotypes Arc.2, Arc.3, Arc.4, Arc.3S and Ipa 6 showed low levels of oviposition non-preference, being classified as deterrents. The genotypes Arc.1S and Arc.1 expressed high levels of antibiosis; Arc.2, Arc.3 and Arc.4 showed the same mechanism, however in lower levels.
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Palavras-chave
Resistência de plantas a insetos, feijão armazenado, caruncho, antixenose, antibiose, Host plant resistance, stored bean grains, bean weevil, antixenosis, antibiosis
Como citar
Ciência e Agrotecnologia. Editora da Universidade Federal de Lavras (UFLA), v. 34, n. 6, p. 1507-1513, 2010.