Browsing by Author "Acevedo-Opazo, C."

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    Classification of winegrape cultivars in Chile and France according to their susceptibility to Botrytis cinerea related to fruit maturity
    (2018) Panitrur-De La Fuente, C.; Valdes-Gomez, H.; Roudet, J.; Acevedo-Opazo, C.; Verdugo-Vasquez, N.; Araya-Alman, M.; Lolas, M.; Moreno, Y.; Fermaud, M.
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    Hydric behaviour and gas exchange in different grapevine varieties (Vitis vinifera L.) from the Maule Valley (Chile)
    (2019) Gutierrez-Gamboa, G.; Perez-Donoso, A. G.; Pou-Mir, A.; Acevedo-Opazo, C.; Valdes-Gomez, H.
    In the near future, stomatal behaviour will be crucial to counteract conditions arising from climate change. Grapevine varieties are classified as either isohydric or anisohydric, depending on the sensitivity of stomata to water deficit and on their water potential homeostasis. However, the great variability observed in different studies indicates that a continuum exists in the range of stomata! sensitivity to water stress. Thus, more knowledge about the hydric behaviour and the gas exchange of isohydric and anisohydric grapevine varieties under different water conditions could lead to the development of irrigation strategies oriented at improving water-use efficiency, yield and berry composition. In this study, research was conducted in order to characterise the stomatal regulation of four different Vitis vinifera L. varieties, namely Pinot noir, Sauvignon blanc, Chardonnay and Merlot, according to soil water status. Measurements of leaf gas exchange, together with measurements of stem water potential (Psi S) and leaf water potential (Psi l), were taken during two seasons. Under conditions of water stress, Chardonnay and Merlot reached a minimum Psi S of -1.67 and -1.68 MPa respectively, and higher levels of water-use efficiency (A(N/)g(S)), of 62.3 and 69.7 mu mol CO2 mol H2O respectively. In Sauvignon blanc and Pinot noir, the minimum Psi S was -1.26 and -1.40 MPa respectively, with lower levels of A r a, (53.1 and 50.5 mu mol CO(2/)mol H2O, respectively). Under conditions of water stress (Psi l < -0.9 MPa and Psi S < -0.6 MPa), all varieties had a significantly increased A(N/)g(S)(1), despite a significant reduction in gas exchange. Therefore, the hydric behaviour and gas exchange observed in this study suggest that Chardonnay and Merlot could be characterised as anisohydric varieties, as they present less sensitive stomata! control, while Pinot noir can be classified as a near-anisohydric variety and Sauvignon blanc as an isohydric variety. New investigations should consider other characteristics of the varieties to classify them better.
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    Identification of main factors affecting the within-field spatial variability of grapevine phenology and total soluble solids accumulation: towards the vineyard zoning using auxiliary information
    (2022) Verdugo-Vasquez, N.; Acevedo-Opazo, C.; Valdes-Gomez, H.; De la Fuente, C. Panitrur; Ingram, B.; Garcia de Cortazar-Atauri, I.; Tisseyre, B.
    Grapevine phenology and total soluble solids (TSS) accumulation are important information to plan agricultural operation in the vineyards over the season. The study aims at identifying the main environmental factors and related high spatial auxiliary information that could be used to define within-field zones of phenology and TSS accumulation. An experiment was carried out in the Maule Valley, Chile, considering two representative vineyards with different environmental characteristics: vineyard 1 (cv. Cabernet Sauvignon) which presents differences in elevation and vineyard 2 (cv. Chardonnay) which is considered flat. Within each vineyard, a regular sampling grid was defined to perform measurements: phenology, TSS accumulation, plant water status, vegetative expression, yield, soil physical properties and soil apparent electrical conductivity. Observations were made during four and two years respectively for vineyard 1 and 2. The analysis of the results is based on principal component analysis (PCA) to identify the relationships between variables. Results show that factors affecting the spatial variability of phenology and TSS accumulation are different for each vineyard. For vineyard 1, topography is the main factor that affects the spatial variability both in phenology and TSS accumulation. For vineyard 2, the soil apparent electrical conductivity was the most important factor explaining the spatial variability observed in the phenology, while balance between vegetative expression and fruit load affected the TSS accumulation. These results highlight the possibility to define zones of differentiated management in relation to the phenology and TSS accumulation using auxiliary information easy to acquire or available with high spatial resolution.