Interacciones entre sitio, plaga y una enfermedad del fuste en una plantación de Populus deltoides cv. Catfish-2 en el bajo delta del Río Paraná (Argentina)

This work is aimed at studying the interactions among the plantation site quality of poplars with damages caused by «Taladro de los Forestales» (Platypus mutatus Chapuis), and with cankers (one trunk disease). We carried out the study in a 2 ha plantation of Populus deltoides cv Catfish-2, which is the most widespread clone in the delta area. The plantation was 12 years old and it was placed in the Low Delta of Paraná River (Argentina). We detected a direct relation among the forest site quality, the presence of the plague (Platypus mutatus) and a trunk disease (cankers). The poplars of greater diameter and height were the most affected trees by the boring insect's attack and they showed the most quantity of active holes and cracks at galleries height, as a consequence of the plague effect, while the poplars of less growth were those more infected by cankers in their trunks. The percentage of plants affected by the boring insect and infected by cankers was significantly greater at the most productive and the highest forest site («albardón» protected by dams). However, the low sites («bañados» protected by dams) had lower growth values and volumetric yields, fewer active holes, less percentage of plants broken by the wind at the height of galleries produced by boring insects and less number of plants with cankers in the trunks.El objetivo del trabajo fue estudiar la relación entre la calidad de sitio de plantación de álamos con los daños causados por el «Taladro de los Forestales» (Platypus mutatus Chapuis) y la relación con una enfermedad del fuste (cancrosis). El estudio se llevó a cabo en 2 ha de una plantación de Populus deltoides cv Catfish-2, uno de los clones de álamos más plantados en el Delta Bonaerense. La plantación de 12 años de edad estaba ubicada en el Bajo Delta del Río Paraná (Argentina). Nosotros detectamos una relación directa entre la calidad del sitio, la presencia de la plaga y de cancros en el fuste. Los álamos de mayor diámetro y altura presentaron un mayor ataque por taladro y una mayor cantidad de orificios activos y rajaduras a la altura de las galerías producidas por Platypus mutatus Chapuis, mientras que los álamos de menor crecimiento fueron los más infectados por cancros en sus fustes. El porcentaje de plantas afectadas por taladro e infectadas por cancrosis fue significativamente mayor en el sitio más productivo y más alto del terreno (albardón endicado). En cambio, los sitios bajos (bañados endicados) mostraron menores valores de crecimiento y productividad de álamos, menor cantidad de orificios activos, menor porcentaje de plantas quebradas por el viento a la altura de las galerías generadas por taladros y menor número de plantas con cancros en el fuste

Modelling consumers' heterogeneous preferences: a case study with Chilean wine consumers

Background and Aims: Understanding consumers' preferences is key to making a successful product, but preferences are heterogeneous. We compare three approaches to consider preference heterogeneity in discrete choice models: (i) systematic preference variations based on socio‐demographic characteristics; (ii) latent classes; and (iii) hybrid choice models with latent variables measuring consumers' attitudes. Methods and Results: Data from a stated choice survey of Chilean wine consumers were analysed using three different approaches; these agreed on average trends but differed in fit and implied different trade‐offs. For example, socio‐demographic characteristics correlate poorly with preferences. Latent classes offer a good fit but do not link preference heterogeneity to consumer characteristics. The hybrid choice model provides the best fit but requires more data, making it more difficult to use this approach in forecasting. Conclusions: The best approach might depend on the research objectives. Using latent classes on a representative sample is the best approach if forecasting is paramount. Modelling attitudes is helpful when more insight into consumers' preferences is sought. Systematic preference variations based on socio‐demographic characteristics are a good choice when only average trends are relevant. Significance of the Study: We make recommendations on how to model preference heterogeneity when studying wine preferences, an issue often overlooked

Evaluation of an active yeast propagation system on fermentation traits and quality of C.V. Carmenère wine

Active dry yeasts (ADY, Saccharomyces cerevisiae) are widely used in oenology due to their potential benefits on the control of fermentation and quality reproducibility among other aspects. On the other hand, yeast propagation systems, so called Active Yeast Systems (AYS), can be useful to optimize the alcoholic fermentation (AF) initial lag phase and reduce production costs. The objective of this work was to determine the predominance of an ADY strain propagated by AYS and the impact of this inoculum on cv. Carmenère wine quality. Lalvin ICV D21 ADY strain was inoculate according to the protocol recommended by the manufacturer (T0), and in parallel, it was propagate by the AYS and then used as inoculum (T1). Yeast strain predominance analyzed by restriction fragment length polymorphism (RFLP) technique indicates that nine (out of 9) yeast colonies obtained from a single sample of the ADY, show the same electrophoretic pattern when compared to the ADY. The results show limited significant differences for the fermentation speed and the yeast cell counting. The result of the physicochemical analysis of the musts and resulting wines showed no significant differences between treatments. A triangular test showed no significant sensory differences between wine

Modelling choice when price is a cue for quality: a case study with Chinese consumers

Experience products are those the quality of which cannot be ascertained until after consumption, forcing consumers to base their purchase decision on an expectation of the product's quality. This expected quality is based on cues available before purchase, among which price is noteworthy, as consumers tend to believe that higher prices imply higher quality. But price also stresses the consumers' budget restriction, inducing a double -and conflicting- global effect on purchase probability. Using the traditional formulation of Random Utility Models for experience goods (i.e. introducing all attributes directly in the utility function) can lead to an endogeneity problem due to the omission of expected quality, introducing bias on the results. Using a stated wine choice experiment conducted in China as a case study, we correct for endogeneity by modelling each alternative's expected quality as a latent variable, explained by all available quality cues, including price. Then we explain choice as a trade-off between price and expected quality. This allows us to separate both effects of price and correct for at least one source of endogeneity while being consistent with behavioural theory; this has either been ignored or not treated correctly in previous literature. Moreover, as the model requires only a single quality indicator for each alternative to achieve identification, the respondents’ burden increases marginally. Our results show that the use of latent variables reduces endogeneity and effectively allows to measure both effects of price separately, obtaining higher significance and correct signs for its parameters

Analysis of volatile compounds in three unifloral native Chilean honeys

Abstract. Three unifloral honeys were identified by the pronounced presence of specific compounds by means of sensorial analysis and SPME-GC-MS. Smoky and resinous ('propolis') odors characterized unifloral "quillay" (Quillaja saponaria) honey. "Corontillo" (Escallonia pulverulenta) honey was characterized by caramel and vanillin aromas, and "ulmo" (Eucryphia cordifolia) honey by having an anise scent with a floral jasmine note. Safranal was a useful marker for "corontillo" honey. Isophorone and cetoisophorone were the distinctive compounds of unifloral "ulmo" honey. In "quillay" honeys, megastigmatrienone, 2-p-hydroxyphenylalcohol and minor quantities of β-pinene and linalool oxide were correlated with their sensory properties such as resinous. Key words: : Ulmo honey, Escallonia or "corontillo" honey, Quillaja honey, SPME-GC-MS analysis. Resumen. Tres mieles monoflorales se identificaron por la presencia notable de compuestos específicos usando análisis sensorial y SPME-GC-MS. Los olores a humo y a resina (o a propóleos) tipificaron la miel de quillay (Quillaja saponaria). La miel de corontillo (Escallonia pulverulenta) se caracterizó por sus aromas a caramelo y a vainilla, y la miel de ulmo (Eucryphia cordifolia) por su fragancia anisada con una nota floral de jazmin. Safranal constituyó un marcador útil para la miel de corontillo, mientras que isoforona y cetoisoforona fueron los compuestos distintivos de la miel monofloral de ulmo. En las mieles de quillay se correlacionaron megastigmatrienona, 2-p-hidroxifenilalcohol y las trazas de β-pineno y óxido de linalool con sus propiedades organolépticas tales como resinosa. Palabras clave: miel de ulmo, miel de corontillo o de Escallonia, miel de Quillaja, análisis SPME-GC-MS