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Avaliação da variabilidade genética intravarietal de variedades antigas de videira
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Orientador(es)
Resumo(s)
Os diferentes genótipos constituintes de uma variedade antiga de videira são marcadamente distintos, relativamente a características quantitativas. Esta variabilidade constitui a base da seleção genética e proporciona a obtenção de materiais selecionados com elevados ganhos relativamente a várias características quantitativas de alto interesse económico, como o rendimento, peso do bago, volume do mosto do bago e características da qualidade do mosto. Numa variedade antiga, a quantificação da variabilidade na fase inicial de seleção permite emitir hipóteses quanto à sua antiguidade, avaliar as mais-valias ao fazer seleção e prever os ganhos de seleção do material selecionado policlonal e planear a fase seguinte de seleção (seleção clonal). Pretende-se assim, estudar a variabilidade intravarietal em 17 castas autóctones portuguesas relativamente a várias características de interesse económico, como rendimento, peso do bago, volume do mosto do bago, acidez total, pH e, no caso das castas tintas, antocianas e fenóis totais.
Foram ajustados modelos lineares mistos a vários conjuntos de dados obtidos ao longo de vários anos, em 25 ensaios de 17 castas autóctones, para quantificação dessa variabilidade intravarietal, fornecendo uma visão atual exaustiva do problema.
Chegou-se a resultados que permitem verificar a existência de castas com variabilidade genética intravarietal bastante elevada para as características avaliadas, o que poderá traduzir elevados ganhos de seleção, mas também a hipótese da antiguidade da domesticação da casta. De um modo geral, as castas que apresentaram maior variabilidade genética intravarietal do rendimento foram também as que revelaram maior nível de variabilidade intravarietal das restantes características.
The different genotypes comprising an old vine variety are markedly distinct with respect to quantitative traits. This variability is the basis for genetic selection and provides selected materials with high genetic gains for several quantitative traits of high economic interest, such as yield and must quality traits. In an old variety, the quantification of the variability in the initial phase of selection allows to make hypotheses regarding its antiquity, to evaluate the added value when making selection, to predict the genetic gains of selection of the polyclonal selected material, and to plan the next phase of selection (clonal selection). The aim of this work is to study the intravarietal diversity in 17 Portuguese autochthonous varieties for several economically important traits, such as yield, berry weight, volume of the must of the berry, total acidity, pH, and for red varieties, anthocyanins, and total phenols. Linear mixed models were fitted to several data sets obtained over several years in 25 field trails of 17 varieties to quantify this intravarietal variability, providing an exhaustive current view of the problem. The results showed that there are varieties with a very high level of intravarietal genetic variability for all the evaluated traits. This will allow to perform polyclonal selection with high genetic gains, and to formulate hypothesis about the antiquity of the domestication of the variety. In general, the varieties that showed high level of intravarietal variability for yield were also the same that showed high level of variability for the other traits.
The different genotypes comprising an old vine variety are markedly distinct with respect to quantitative traits. This variability is the basis for genetic selection and provides selected materials with high genetic gains for several quantitative traits of high economic interest, such as yield and must quality traits. In an old variety, the quantification of the variability in the initial phase of selection allows to make hypotheses regarding its antiquity, to evaluate the added value when making selection, to predict the genetic gains of selection of the polyclonal selected material, and to plan the next phase of selection (clonal selection). The aim of this work is to study the intravarietal diversity in 17 Portuguese autochthonous varieties for several economically important traits, such as yield, berry weight, volume of the must of the berry, total acidity, pH, and for red varieties, anthocyanins, and total phenols. Linear mixed models were fitted to several data sets obtained over several years in 25 field trails of 17 varieties to quantify this intravarietal variability, providing an exhaustive current view of the problem. The results showed that there are varieties with a very high level of intravarietal genetic variability for all the evaluated traits. This will allow to perform polyclonal selection with high genetic gains, and to formulate hypothesis about the antiquity of the domestication of the variety. In general, the varieties that showed high level of intravarietal variability for yield were also the same that showed high level of variability for the other traits.
Descrição
Mestrado em Engenharia Agronómica. Universidade de Lisboa, Instituto Superior de Agronomia
Palavras-chave
Vitis vinifera L. seleção genética genética quantitativa conservação da videira clones de videira genetic selection quantitative genetics linear mixed models grapevine clones
Contexto Educativo
Citação
Reis, M.F.M.A.B. Avaliação da variabilidade genética intravarietal de variedades antigas de videira. Lisboa: ISA-Universidade de Lisboa, 2022. Dissertação de Mestrado
Editora
Instituto Superior de Agronomia, Universidade de Lisboa