Fatores químicos e comportamentais envolvidos na escolha de genótipos de Solanum lycopersicon por fêmeas de Tuta absoluta

• Autor(a) principal: Ataíde, Lívia Maria Silva
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3909
• topic: Genótipos de tomate; Túnel de vento; Oviposição; Tuta absoluta; Tomato genotypes; Wind tunnel; Oviposition; Tuta absoluta; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::ENTOMOLOGIA AGRICOLA

Higher plants release a wide variety of volatile compounds which are perceived by specialized neurons chemo-receptor in the insect antenna. Females choose host plants before and during oviposition showing susceptible and resistant plants between diferent genotypes. We believe that chemical stimuli produced by tomato plants should regulate, their interspecific relationship with pest insects, including Tuta absoluta. Therefore, the objective of this study was to carry out by behaviour studies involving olfatometry tecniques in wind tunnel and chemical identification of plants volatiles in gas cromatography and ovipositions tests, the mechanisms involved in the selection of susceptible and resistant plants by T. absoluta. To carry out this study, were grown in a greenhouse five genotypes of Solanum lycopersicon: four subsamples of Vegetable Germplasm Bank of the UFV (BGH-674, BGH-1497, BGH- 1708, BGH-489) and the variety Santa Clara. In the wind tunnel, the response of mated females of T. absoluta to this diferent genotypes was studied. After this first analysis, was examined the presence of seven chemical compounds and their likely influence on the attractiveness to females. Considering this, the relative abundance of total terpenes varied among genotypes (p=0.0153) and was negatively related to attractiveness to females. The oviposition test had the aim to assess whether females of T. absoluta would be able to discriminate oviposition sites, and thus accomplish diferent oviposition between the genotypes. For this, only a mated female was confined into every cage and were made three types of choice test. The first offering the opportunity to choose between all genotypes, puting them within a cage; the second, individualizing each genotype in small cages with no chance to choose and the third, contrasting two genotypes (one resistant and one susceptible). After 24 hours the number of eggs deposited by females were counted. However, it was observed that for the first experiment (p=0.924), the number of eggs was not affected by genotype. In the second one, this diference was marginally significant (p=0.06) and in the third experiment, only for the contrast Santa Clara/BGH-674 the number of eggs oviposited were bigger in the variety Santa Clara (p=0.025). Finally, trying to establish a link between localization and oviposition it could be suggested that volatile compounds are more important than morphological characteristics of the leaf that would have had little influence on oviposition decision of females. Considering these results, the subsamples BGH-1497, BGH-674 and BGH-1708 were considered resistant to antixenosis and its use as a tool in the selection of host plants and pest monitoring shows to be interesting.