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The effect of leaf area to crop weight ratios on fruit quality and performance of grapevine (Vitis vinifera cv. Pinot Noir)
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Orientador(es)
Resumo(s)
Vine performance, fruit and wine composition were investigated on field grown Pinot Noir grapevines
subjected to a range of leaf removal and cluster thinning treatments. Both treatments were applied in
three levels (25 %, 50 % and 100 % of leaves and clusters retained, respectively) at the phenological
stage of pea-size. New emerging leaves were removed as they appeared.
Veraison was delayed when leaf area to fruit weight ratio (LA/Y) dropped below a certain threshold
(13 cm2 g-1). On the contrary a high LA/Y ratio (> 26 cm2g-1) did not show any difference on fruit
colouration. No significant differences in single leaf photosynthetic rate were observed between the
treatments, however, there was a trend that vines from the 50 % leaf retained treatment tended to
exhibit highest values for stomatal conductance and photosynthesis. Defoliated vines compensated for
a restricted leaf area by increasing individual leaf size of the remaining leaves.The results of the present study suggest that fruit is produced at the expense of vegetative growth.
High crop levels resulted in a decrease of individual leaf size. Moreover, pruning weight and LA/Y
ratio were positively correlated. Sugar accumulation in grape berries were shown to follow a
saturation curve. An increase of the source to sink ratio up to a certain point was accompanied by an
increase in sugar accumulation. If this threshold was exceeded, additional leaf area did not promote
higher sugar accumulation, indicating that the vine might be sink-limited.
The most severe defoliation treatment significantly reduced berry size and berry weight. No consistent
pattern between titratable acidity, pH and YAN and leaf area to fruit weight ratio could be found.
Wine tannin content and wine colour parameters were not affected by the treatments
Descrição
Mestrado Vinifera EuroMaster - Instituto Superior de Agronomia
Palavras-chave
vitis vinifera Pinot Noir leaf area fruit quality
Contexto Educativo
Citação
Pasch, L.A. - The effect of leaf area to crop weight ratios on fruit quality and performance of grapevine (Vitis vinifera cv. Pinot Noir). Lisboa: ISA, 2014, 103 p.