13 research outputs found

    Identifying the location of olive fruit abscission

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    For high quality oil, table olive characteristics, and reduction of alternate bearing tendencies, it is often desirable to harvest olive fruits prior to full physiological maturity, that is, before the natural separation zone has differentiated. Olive fruit abscission can occur at different positions, mainly fruit-pedicel, pedicel rachis and peduncle-branch, apparently varying according to cultivar, fruit weight, and fruit maturation. Precisely identifying the location of separation is critical for studying the differentiation of the abscission zone or zones and testing the effectiveness of harvest procedures, including the mode of action of different fruit-loosening chemicals. We determined the olive fruit abscission zone position under natural conditions, throughout the complete fruit maturation period, for two cultivars differing in fruit size. The major separation zone for the cultivars studied was between the fruit and pedicel. For cv. Picual, abscission in zones other that fruit-pedicel occurred in less than 15% of the fruit at all dates throughout the maturation period, whereas in cv. Hojiblanca, the percentages of fruits detached at peduncle-shoot (27%) and pedicel-rachis (19%) were initially substantial, and then decreased progressively during fruit maturation. Our data clearly indicate both varietal and temporal differences which should be taken into account not only when testing fruit-loosening compounds but in extrapolating test results to different varieties or dates. Fruit weight did not appear affect the abscission location. The method we used, of counting the different detached units, is simple and effective for determining the position of fruit abscission.Financial support was provided by I.N.I.A. (Spanish National Agricultural Research Service) project CAO99-007 and Spanish Ministry of Education project REN2001-1502-CO3-02

    Estimating reference evapotranspiration with atmometers in a semiarid environment

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    Reference evapotranspiration (ET0) estimations require accurate measurements of meteorological variables (solar radiation, air temperature, wind speed, and relative humidity) which are not available in many countries of the world. Alternative approaches are the use of Class A pan evaporimeters and atmometers, which have several advantages compared to meteorological stations: they are simple, inexpensive and provide a visual interpretation of ET0. The objectives of the study were to compare the evaporation from atmometers (ETgage) with the evapotranspiration estimated by the FAO-56 Penman-Monteith equation (ET0PM) and to evaluate the variability between three modified atmometers of a commercial model. Comparison between daily ETgage measured by the atmometer and ET0PM showed a good correlation. However, ETgage underestimated ET0PM by approximately 9%. Differences between ETgage and ET0PM ranged from -2.4 to 2.2 mm d-1 while the mean bias error was -0.41 mm d-1. Underestimations occurred more frequently on days with low maximum temperatures and high wind speeds. On the contrary, atmometer overestimations occurred on days with high maximum temperatures and low wind speeds. Estimates of ET0 using the atmometer appeared to be more accurate under non-windy conditions and moderate temperatures as well as under windy conditions and high temperatures. Atmometers 2 and 3 overestimated the evaporated water by atmometer 1 with a maximum variability of cumulative water losses of 4.5%. A temperature-based calibration was performed to improve the atmometer accuracy, using maximum temperature as an independent variable, with good results.Evaporation Bellani cup Penman-Monteith equation Calibration

    Oli-24 capacidad de brotación y floración de las yemas del olivo

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    Trabajo presentado en EXPOLIVA2015, celebrado en Jaén (España) del 11 al 14 de mayo de 2005.La formación de los brotes vegetativos y de las inflorescencias depende de la formación y actividad de las yemas localizadas en el ápice del brote y en las axilas de las hojas. La capacidad del olivo de crecer en situaciones marginales, resistir a cambios climáticos y adaptarse a las modernas técnicas agronómicas de poda y plantación intensiva, se debe al desarrollo de múltiples zonas de crecimiento desde donde las yemas son originadas. Las yemas son estructuras frágiles y pueden verse afectadas por condiciones adversas que ocasionan su caída prematura afectando a la brotación vegetativa o floral y con ello la futura producción. Observaciones de las yemas axilares del olivo han indicado la presencia de una estructura pequeña y de apariencia similar a una yema, localizada en la axila formada entre la base de la yema principal y el brote. Un estudio detallado ha confirmado que estas estructuras son “yemas accesorias” o “secundarias” demostrando que su presencia y grado de desarrollo dependen del estado productivo del árbol y del tipo y edad del brote en donde se ubican las yemas. Se analiza el papel de estas yemas accesorias en el proceso de brotación vegetativa y floral.Este trabajo ha sido financiado por el proyecto REN2001-1502-CO3-02 del Ministerio de Educación y Ciencia de España.Peer reviewe

    Distribución de la longitud de los brotes nuevos del olivo y su relación con la floración

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    Comunicación presentada en el XV Simposium de EXPOLIVA, celebrado en Jaén del 11 al 13 de mayo de 2011.En este estudio se analizó el crecimiento de brotes nuevos y su posterior tasa de floración en árboles de olivo, var. Hojiblanca, en condiciones de carga y descarga durante dos campañas consecutivas. Para ello se utilizaron ramas de 5 años como unidades de estudio en las que se evaluaron todos los brotes existentes. El número de brotes nuevos y la longitud total estuvieron condicionados a la presencia de frutos en los árboles. Así, durante un año de descarga, el crecimiento de brotes nuevos fue bastante superior al registrado en árboles en carga. Los brotes menores o iguales a 4 cm fueron los más representativos en ambas condiciones de carga, representando el 74% en los árboles en descarga y el 60% en los de carga. Los brotes de 6 a 16 cm y los de 16 a 30 cm representaron, tanto en carga como en descarga, menos del 35% y 5% del total de brotes, respectivamente, mientras que los brotes superiores a 30 cm fueron inapreciables, especialmente en árboles en carga. La formación de las inflorescencias no estuvo condicionada por la longitud de los brotes pero sí estuvo fuertemente determinada por el estado de carga del año anterior. Así, en los árboles anteriormente en descarga, el porcentaje de brotes reproductores fue de 93 a 100% en todas las longitudes. En los árboles en carga, por el contrario, el porcentaje de brotes reproductores fue muy bajo y nada uniforme entre las diferentes longitudes.Peer Reviewe

    Relationship between reproductive behavior and new shoot development in 5-year-old branches of olive trees (Olea europaea L.)

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    The development of new shoots plays a central role in the complex interactions determining vegetative and reproductive growth in woody plants. To explore this role we evaluated the new shoots in the olive tree, Olea europaea L., and the effect of fruiting on new shoot growth and subsequent flowering. Five-year-old branches served as canopy subunits in order to obtain a global, whole-tree view of new shoot number, size and morphological origin. The non-bearing trees had many more shoots than the fruit-bearing trees, and a greater number of longer shoots. In both bearing conditions, however, the majority of shoots were less than 4 cm long, with shoots of progressively longer lengths present in successively decreasing frequencies. Six major shoot types were defined on the basis of apical or lateral bud origin and of parent shoot age. On fruit-bearing trees, the new shoots originated predominantly from the shoot apex, while on non-fruiting trees, they formed mainly from axillary buds, but in both cases, they tended to develop on younger parent shoots. The previous bearing condition of the tree was the main determinant for subsequent inflorescence development, which was independent of both shoot type and length. Thus, reproductive behavior strongly affected both the amount and type of new branching, but subsequent flowering level was more influenced by previous bearing than by the potential flowering sites on new shoots. © 2011 Springer-Verlag.This work was financed by the Spanish Ministry of Education projects REN2001-1502-CO3-02/GLO and AGL2005-00930.Peer Reviewe

    Interaction between shoot growth and reproductive behavior in olive trees

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    Trabajo presentado en el V International Symposium on Olive Growing, celebrado en Esmirna (Turquía) el 27 de septiembre de 2004.In the olive tree, (Olea europaea L.), bearing status exerts a strong influence on shoot growth as well as on flowering in the following year. Similar to various woody species, a heavy crop load reduces vegetative growth and return-to-bloom. Information is lacking, however, as to the precise nature of the effect of bearing condition on shoot growth, and the relationship between the type of shoot growth and its potential for flowering. We characterized shoot growth architecture in detail for six heavily bearing "on" and six non-bearings "off" trees. Five four-year-old branches were selected on each tree in summer and then detached in the winter dormancy period, at which time all current season shoots were measured and their morphogenetic origin determined. Flowering behavior was then monitored for three similar previously marked branches remaining on the trees, paying particular attention to the characteristics of the shoots on which inflorescences were formed. The bearing condition of the tree influenced both the site of origin and the growth of current-year shoots. A greater proportion of current-year-shoots in "off" trees originated by lateral branching, whereas in "on" trees shoot growth tended to occur by elongation from the shoot apex. Shoot number was three times higher for "off" than "on" trees. The size range and distribution among current-year-shoots, however, was quite similar between "on" and "off" trees, showing only a small trend toward the formation of a higher proportion of short shoots in the "on" trees and a higher proportion of longer shoots in the "off" trees. Flowering behavior was governed by the tree's previous season bearing condition, and was completely independent of shoot type.Peer reviewe

    La suspensión del riego invernal como estimulador de la floración del olivo en zonas de invierno sin frio

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    Póster presentado en el XVI Simposium de EXPOLIVA, celebrado en Jaén del 8 al 11 de mayo de 2013.La falta de bajas temperaturas invernales, necesarias para retirar el reposo en las yemas reproductoras, es uno de los factores que ha limitado la ampliación de las zonas de cultivo del olivo. En la costa de Perú, donde el frío invernal es ausente, la floración del olivo es estimulada tradicionalmente por un periodo de suspensión de riego durante el invierno. Para conocer el funcionamiento de dicho sistema se sometieron varios árboles de olivo de cv. 'Frantoio’ y ‘Criolla’, en condiciones de ausencia de frío, a un periodo de suspensión de riego invernal (SRI) en Tacna (Perú). Varios grupos de brotes se muestrearon a las 5, 6 y 9 semanas de SRI para analizar la morfología de las yemas, y se prepararon estaquillas para, tras un periodo de forzado, evaluar la brotación reproductora. Las yemas de ambas variedades presentaron 4-5 nudos y similares dimensiones internas durante el periodo de SRI. En las estaquillas, la brotación repro ductora no se expresó tras 5 semanas de SRI, aumentó con el incrementó del tiempo de suspensión de riego, y fue mayor en ‘Criolla’ que en ‘Frantoio’. Un análisis de las yemas de las mismas variedades en condiciones habituales de frío invernal (Córdoba, España), indicó que no existen diferencias morfológicas respecto a las yemas analizadas en condiciones de suspensión de riego. Ambas variedades, en condiciones de ausencia de frío, presentaron una alta brotación reproductora, lo que sugiere que el método de SRI es efectivo para estimular la floración.Peer Reviewe

    Irrigation withholding effects on olive reproductive bud development for conditions with insufficient winter chilling

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    In the Mediterranean areas where olive domestication originated, flowering of the tree occurs once florally induced buds receive sufficient chilling during the winter dormancy period, followed by warmer temperatures adequate for budburst and subsequent floral differentiation. In locations such as Tacna, Peru, where winter temperatures provide insufficient cold, flowering is traditionally stimulated by withholding irrigation. As an initial step for determining the specific requirements and potential of this system, we observed morphological and structural aspects of buds during winter dormancy irrigation witholding, and under budburst forcing following non-irrigated periods of different lengths. Buds and flowering were observed on current-year shoots from previously non-bearing trees of 'Frantoio' and 'Criolla', a prominent local cultivar. Floral budbreak capacity following 5, 6 and 9 weeks water-withholding periods was tested by forcing leafy cuttings from the affected trees in a greenhouse and monitoring morphogenetic changes. In both cultivars dormant buds presented 4-5 nodes and similar internal dimensions, and remained unchanged throughout the irrigation suspension period. Reproductive budburst on the cuttings did not occur following 5 weeks witholding, increased with successively longer periods, and was greater for 'Criolla' than 'Frantoio'. Comparison to buds of the same cultivars in standard winter dormancy conditions (Cordoba, Spain) indicated similar bud morphology and behavior to that observed with the irrigation suspension scenario. Flowering on shoots maintained on the trees confirmed the effectiveness of the irrigation withholding method for both cultivars. Overall, the greater and more rapid floral budbreak in 'Criolla' suggests it may be better adapted to the local climatic and cultivation conditions than 'Frantoio'.Peer Reviewe

    Soil erosion control, plant diversity, and arthropod communities under heterogeneous cover crops in an olive orchard

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    A 3-year experiment compared in an olive orchard the effect of different cover crops’ composition on runoff, water erosion, diversity of annual plants, and arthropod communities which could provide an alternative to conventional management based on tillage (CT). The cover crops evaluated were a seeded homogeneous grass (GC), a seeded mix of ten different species (MC), and a non-seeded cover by vegetation naturally present at the farm after 20 years of mowing (MC). The results suggest that heterogeneous cover crops can provide a viable alternative to homogeneous ones in olives, providing similar benefits in reducing runoff and soil losses compared to management based on bare soil. The reduction in soil loss was particularly large: 46.7 in CT to 6.5 and 7.9 t ha year in GC and MC, respectively. The heterogeneous cover crops resulted in greater diversity of plant species and a modification of the arthropod communities with an increased number of predators for pests. The reduction of the cost of implanting heterogeneous cover crops, improvement of the seeding techniques, and selection of species included in the mixes require additional research to promote the use of this practice which can deliver enhanced environmental benefits.This study has been possible thanks to the support of Syngenta from 2002 to 2013, through projects ProTerra I, II and Biosuelo. Since 2009, some additional measurements and analysis have been possible to support by the projects P08-AGR-03643, P12-AGR-931, AGL2015-65036-C3-1, RESEL (Spanish Ministry for Environment and Rural and Marine Affairs), and FEDER funds. We also want to acknowledge the contribution of three anonymous reviewers who had helped greatly to improve the quality of the original manuscript.Peer Reviewe
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