Publicação
Olive anthracnose: passive defense of tolerant and susceptible Portuguese Olea europaea L. cultivars and its effect on olive oil quality
| Resumo: | Olive anthracnose, caused by different species of the genus Colletotrichum, is the most important fruit disease of olive fruit worldwide. In Trás-os-Montes region was noticed that under the same agro-climatic conditions and in the same period of time, the disease is more severe in some cultivars (e.g. cv. Madural) than in others (e.g. cv. Negrinha de Freixo). But the possible reasons for these differences were never studied. In this study, the susceptibility of these two cultivars to olive anthracnose was evaluated through bioassays, and the results obtained were further related with physical and chemical olive traits frequently associated to host plant defense. The effect of olive anthracnose on olive oil quality was also evaluated. Both disease incidence and severity in Madural was up to 16-fold significantly higher than in Negrinha de Freixo. This effect was observed in immature fruits, being fewer differences among cultivars as fruit matured. Physical analysis of fruit cuticle thickness and fruit surface observations by light microscopy (i.e. average number of lenticels, and their diameter) reveal significant differences between cultivars. These differences are not related to the cultivar susceptibility. Chemical analyses concerning fruit volatiles by GC-MS revealed significant differences between cultivars. Olive oil from diseased Madural olives had significantly higher free acidity and peroxide values, and lower oxidative stability and phenolic compounds, than olive oils from healthy fruits. Altogether, the results offer new insights into physical and chemical defense mechanisms in olive fruit that could lead to novel strategies for management of olive anthracnose. |
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| Autores principais: | Silva, Vítor Cardoso Ferreira da |
| Assunto: | Colletotrichum spp. Olea europaea Physical defense Chemical defense Oil quality |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Olive anthracnose, caused by different species of the genus Colletotrichum, is the most important fruit disease of olive fruit worldwide. In Trás-os-Montes region was noticed that under the same agro-climatic conditions and in the same period of time, the disease is more severe in some cultivars (e.g. cv. Madural) than in others (e.g. cv. Negrinha de Freixo). But the possible reasons for these differences were never studied. In this study, the susceptibility of these two cultivars to olive anthracnose was evaluated through bioassays, and the results obtained were further related with physical and chemical olive traits frequently associated to host plant defense. The effect of olive anthracnose on olive oil quality was also evaluated. Both disease incidence and severity in Madural was up to 16-fold significantly higher than in Negrinha de Freixo. This effect was observed in immature fruits, being fewer differences among cultivars as fruit matured. Physical analysis of fruit cuticle thickness and fruit surface observations by light microscopy (i.e. average number of lenticels, and their diameter) reveal significant differences between cultivars. These differences are not related to the cultivar susceptibility. Chemical analyses concerning fruit volatiles by GC-MS revealed significant differences between cultivars. Olive oil from diseased Madural olives had significantly higher free acidity and peroxide values, and lower oxidative stability and phenolic compounds, than olive oils from healthy fruits. Altogether, the results offer new insights into physical and chemical defense mechanisms in olive fruit that could lead to novel strategies for management of olive anthracnose. |
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