Influência da forma de condução na produtividade e qualidade da Touriga Nacional
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2017-09-13
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Este estudo teve como principal objetivo estudar a influência da forma de condução, na produtividade e qualidade da casta Touriga Nacional, tendo por base a condução em poda curta (cordão bilateral), e em poda longa (guyot duplo), durante o ano vitícola de 2015. A Touriga Nacional é uma casta com elevada história e importância em Portugal, de origem muito antiga nas regiões vitivinícolas do Dão e do Douro, onde apenas era cultivada. É uma casta tinta autóctone portuguesa, apta à produção de vinho de elevada qualidade. Devido à selecção clonal que tem sido realizada na casta nos últimos anos, o seu cultivo tem vindo a aumentar, após quase a sua extinção, fazendo com que atualmente esteja presente em todas as regiões vitivinícolas portuguesas e também em algumas regiões internacionais. No ensaio a Touriga Nacional, encontra-se enxertada no porta-enxerto 1103 P, (Vitis berlandieri x Vitis rupestris). Estando conduzida em duas formas de condução, em cordão bilateral (podado a talão) e em guyot duplo (podado a talão e vara), ambas pertencem às formas de condução de pequena expressão vegetativa, estando associadas a baixas produtividades unitárias e a elevadas densidades de plantação. Determinou-se a densidade da parede vegetativa ao nível dos cachos e ao nível vegetativo, com o método do “Point Quadrat”, onde se avaliaram os parâmetros do número de camadas de folhas, da percentagem de buracos, da percentagem de folhas interiores e exteriores, e da percentagem de cachos interiores e exteriores. Determinou-se a superfície foliar exposta, expressa em m²\ha. À data de vindima foi registada a produtividade e contabilizado o número de cachos, para a obtenção do peso médio de um cacho, Para além do registo da carga deixada à poda, à data da operação foi determinada a expressão vegetativa e a estimativa do vigor. Após a colheita dos bagos à data de vindima, em laboratório efetuou-se a determinação do peso médio do bago, o teor de açucares, as antocianinas totais, o teor de polifenóis totais, o valor de pH e também o valor da acidez total.
Após a recolha dos dados e do seu devido tratamento estatístico com recurso ao JMP8 através da análise de variância (ANOVA) e da aplicação do teste de separação de médias Tukey HSD
Ao nível da parede de vegetação não se obteve diferenças significativas (P>0,05), nos parâmetros determinados, apenas se obteve diferenças significativas (0,01≤P<0,05), na percentagem de cachos interiores, onde o cordão bilateral obteve valores superiores, e também na percentagem de cachos expostos, onde o guyot duplo apresentou valores superiores, tendo ambas formas apresentado uma parede vegetativa equilibrada. Também nos parâmetros da fertilidade e do vigor apresentado, não existiram diferenças significativas entre as duas formas de condução, tendo as duas, revelado neste ano, uma boa fertilidade e um elevado vigor. Nos parâmetros relacionados com a produtividade e da qualidade obtidos, também não existiram diferenças significativas (P>0,05), entre as duas formas de condução, tendo ambas apresentado uma produção e qualidade, dentro dos valores que seriam espectáveis por parte da casta Touriga Nacional.
The main purpose of this investigation was to study the influence of the trelling system in Touriga‟s Nacional productivity and quality, based on the influence of the short pruning system (bilateral cord) and on long pruning system (double gouyot) during the wine year of 2015. Touriga Nacional is a grape variety of high and historical importance in Portugal, it has an ancient origin in the wine producing regions of Dão and Douro, where it was cultivated. It is a Portuguese autochthonous red variety, suitable for the wine production, of a very high quality. After almost extinction at nationally the variety has been gaining more importance, this is due to clonal selection that has been done, making this variety present in every Portuguese wine producing regions and also at an international level. In the assay, Touriga Nacional is grafted in the 1103 P rootstock (Vitisberlandieri x Vitisrupestris). It has two trelling systems, bilateral cord (pruned by bead) and double gouyot (pruned by bead and stick), both small vegetative expression forms, associated to low unitary productivity and high plantation density. It was determined the vegetation wall density at the grape clusters level and at the vegetative level with the “Point Quadrat” method, it was evaluated the layer of leaves, the holes percentage, the interior and exterior leaves percentage and the interior and exterior bunches. It was also determined the exposed leaf surface, expressed in m2/ha. At the vintage date it was registered the productivity and the brunches number, in order to obtain the medium brunches weight. Besides it was done the registration of the charge left at the pruning date, at the operation date it was determined the vegetative expression and the vigor estimation. In laboratory, after the grapes harvest at the vintage date, it was determined the average weight of grapes, the sugar content, the totality of anthocyanins, the totality of plyphenols index, the pH value and the total acidity value. After the data collection and its statistical treatment, using the JMP8 with the analysis of variance (ANOVA) and the application of the Tukey HSD mean separation. In the vegetative wall there was no significant differences (P>0.05), and relativity to the other parameters there was only significant differences (0.01≤P≥0.05) in the percentage of interior grapes, where the bilateral cord proved superior values and in the percentage of exposed grapes where the gouyot proved superior values, having both systems a balanced vegetative wall. Also in the vigor and fertility parameters there were no significant differences between both systems, in this year both reveled good results for these parameters. In the parameters related with the productivity and quality obtained, there were also no significant differences (P>0.05) resulting both systems in good productivity and quality according to the expected for the Touriga Nacional grapes.
The main purpose of this investigation was to study the influence of the trelling system in Touriga‟s Nacional productivity and quality, based on the influence of the short pruning system (bilateral cord) and on long pruning system (double gouyot) during the wine year of 2015. Touriga Nacional is a grape variety of high and historical importance in Portugal, it has an ancient origin in the wine producing regions of Dão and Douro, where it was cultivated. It is a Portuguese autochthonous red variety, suitable for the wine production, of a very high quality. After almost extinction at nationally the variety has been gaining more importance, this is due to clonal selection that has been done, making this variety present in every Portuguese wine producing regions and also at an international level. In the assay, Touriga Nacional is grafted in the 1103 P rootstock (Vitisberlandieri x Vitisrupestris). It has two trelling systems, bilateral cord (pruned by bead) and double gouyot (pruned by bead and stick), both small vegetative expression forms, associated to low unitary productivity and high plantation density. It was determined the vegetation wall density at the grape clusters level and at the vegetative level with the “Point Quadrat” method, it was evaluated the layer of leaves, the holes percentage, the interior and exterior leaves percentage and the interior and exterior bunches. It was also determined the exposed leaf surface, expressed in m2/ha. At the vintage date it was registered the productivity and the brunches number, in order to obtain the medium brunches weight. Besides it was done the registration of the charge left at the pruning date, at the operation date it was determined the vegetative expression and the vigor estimation. In laboratory, after the grapes harvest at the vintage date, it was determined the average weight of grapes, the sugar content, the totality of anthocyanins, the totality of plyphenols index, the pH value and the total acidity value. After the data collection and its statistical treatment, using the JMP8 with the analysis of variance (ANOVA) and the application of the Tukey HSD mean separation. In the vegetative wall there was no significant differences (P>0.05), and relativity to the other parameters there was only significant differences (0.01≤P≥0.05) in the percentage of interior grapes, where the bilateral cord proved superior values and in the percentage of exposed grapes where the gouyot proved superior values, having both systems a balanced vegetative wall. Also in the vigor and fertility parameters there were no significant differences between both systems, in this year both reveled good results for these parameters. In the parameters related with the productivity and quality obtained, there were also no significant differences (P>0.05) resulting both systems in good productivity and quality according to the expected for the Touriga Nacional grapes.
Descrição
Dissertação de Mestrado em Engenharia Agronómica
Palavras-chave
Qualidade (Touriga Nacional) , Porta-enxerto , Produtividade , Forma de condução