Article

Evaluation of the present information on the mechanisms leading to flower bud induction, evocation and differentiation in Olea europaea

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Abstract

Environmental factors such as suitable light and thermal conditions are essential for the reproductive development of olive buds. However, the tree and its buds have to be in a suitable responsive physiological state in order to respond. Furthermore sufficient well developed buds from the previous season with a good nutritive balance, capable to differentiate are required on the tree. In the present paper, we are demonstrating the changes in the nutritional state of the tree developing in ON and OFF years affecting the responsiveness of the buds and level of vegetative growth to the environmental conditions. After a heavy crop a nutrient dilution occurred and vegetative growth is inhibited. Thus, a following growing season is required to regain a good nutrient balance for generating vegetative growth with sufficient buds responsive to environmental differentiation stimuli for the initiation of the next ON year.

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... Sanewski (2010) stated that such a flowering pattern occurs in Syzygium species and the author related it to abrupt changes in water availability and temperature in monsoon sites. Troncoso et al. (2006) reported that flowering in Olea europaea is not an annual event and observed a considerable depletion of the N and K contents in the leaves at the end of the fruiting year and an increase in these values at the end of the non-flowering season. They stated that a recovery of the mineral content is required for flower bud differentiation to reoccur and water and thermal stress may induce an imbalance between vegetative development and fruiting. ...
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Syzygium alternifolium is a semi-evergreen mass-flowering tree species of dry deciduous forest in the southern Eastern Ghats of India. It is a mass bloomer with flowering during dry season. The floral traits suggest a mixed pollination syndrome involving entomophily and anemophily together called as ambophily. Further, the floral traits suggest generalist pollination system adapted for a guild of pollinating insects. The plant is self-incompatible and obligate out-crosser. The flowers are many-ovuled but only a single ovule forms seed and hence, fruit and seed set rates are the same. Natural fruit set stands at 11%. Bud infestation by a moth, flower predation by the beetle, Popillia impressipyga and bud and flower mounds significantly limit fruit set rate. The ability of the plant to repopulate itself is limited by the collection of fruits by locals due to their edible nature, short viability of seeds, high seedling mortality due to water stress, nutrient deficiency and erratic rainfall or interval of drought within the rainy season. Therefore, S. alternifolium is struggling to populate itself under various intrinsic and extrinsic factors. Further studies should focus on how to assist the plant to increase its population size in its natural area taking into account the information provided in this paper.
... (Cuevas et al., 1994). En tercer lugar, también se ha detectado que la viabilidad de las flores en las inflorescencias y el porcentaje de cuajado serán menores tras un año "de carga" (Lavee, 2007;Troncoso de Arce et al., 2012). ...
Thesis
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The olive (Olea europaea L.) is the leading commercial tree crop in the Mediterranean area. Its reproductive cycle displays considerable variations due to inherent genetic factors but also to climate response. This thesis provides a detailed analysis and modelling of the olive reproductive cycle and its response to a range of environmental variables in the southern Iberian Peninsula. Analysis was based on phenological, aerobiological and meteorological data recorded over the last 30 years in the province of Córdoba (Andalusia, Spain), the second-largest olive-oil-producing province in Andalusia, which is in turn the world’s largest producing region. A more thorough knowledge of the factors governing year-on-year changes in olive flowering and fruit production is clearly of agricultural interest. It is also useful for medical purposes—since olive pollen is highly allergenic—and for ecological reasons, given that the wild olive Olea europaea var. sylvestris Brot., is a characteristic shrub used as a bioindicator for Mediterranean ecosystem. Although the thesis focuses mainly on the behaviour and phenological response of the olive tree in the province of Córdoba, Chapter IV offers an overview of olive production in the Mediterranean area, drawing on data for Andalusia (Spain), Italy and Tunisia. A statistical analysis is made of the correlations between various environmental factors and critical features of the olive reproductive cycle (flowering intensity, floral phenology and fruit production). The results are used in the construction of models to describe and predict the reproductive cycle, from the earliest phases through to harvest. These models are of considerable scientific interest and can readily be transferred for social applications, since they enable the prediction—several months in advance—of major biological events such as the timing, duration and intensity of flowering and the volume of fruit production. Chapters I and II “Biometeorological and autoregressive indices for predicting olive pollen intensity” and “Year clustering analysis for modelling olive flowering phenology” analyse variables relating to flowering intensity, expressed in this anemophilous species by the Pollen Index. The first chapter focuses specifically on the construction of indices to account for year-on-year variations in olive flowering intensity, while in the second chapter a cluster analysis is used to group years with similar meteorological and phenological characteristics and to distinguish those variables most influencing floral phenology, and more particularly flowering intensity. In Chapter 1, pollen production is modelled using bioclimatic and autoregressive indices which account for the influence and impact of a range of environmental variables. The method designed for the construction of these indices enables analysis of the role played by extreme weather events in flowering. The autoregressive index provides crucial information on the dynamics of the olive reproductive cycle. For the mathematical modelling of flowering intensity in Chapter II, a “three-step method” is used, consisting in grouping using a clustering technique, classification using artificial neural networks, and modelling using partial least squares regression. The findings show that the environmental variables most affecting and governing flowering intensity in the province of Córdoba are rainfall during the period prior to flowering and temperature during the month of March. Effective models are also constructed to predict pollen emission intensity; these are especially valuable in preventing symptoms in patients allergic to olive pollen. Chapter III “Modelling olive phenological response to weather and topography” examines the environmental factors affecting each phase of the olive’s floral phenology in the province of Córdoba. The topographical and meteorological variables most influencing the response of different local olive populations and varieties are identified. The topographical factors most affecting reproductive phenology are altitude and East-west orientation of the steepest slope, while the most important weather-related variables are winter temperature, spring temperature and water availability during reproductive organ development. Finally, Chapter IV “Better prediction of Mediterranean olive production using pollen-based models” analyses the factors that determine olive fruit production in the Mediterranean Basin, focussing on Andalusia—Spain’s largest olive-producing region—Italy and Tunisia; for this purpose, for this purpose, flowering intensity and weather-related factors are taken as the major variables Harvest size is modelled using data from the world’s largest olive-oil-producing regions, in order to draw overall conclusions regarding the bioclimatological characterization of the olive, with a view to enabling the construction of regional prediction models applicable to the Mediterranean Basin as a whole. The results of this thesis help to improve the bioclimatic characterisation of the olive, as well as contributing to our knowledge both of the olive’s response to environmental conditions and of the biology of its reproductive cycle. The results were obtained using new, purpose-designed statistical methods which will be useful in future research both in the study area and in other olive-producing regions, and may provide a basis for the phenological modelling of other tree species.
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Résumé La fertilisation est une composante essentielle dans la conduite d’une oliveraie. Elle est destinée à restituer les éléments nutritifs prélevés par la culture au cours de son cycle de développement pour assurer le renouvellement des pousses et la production d’olives et d’huile. Chez l’olivier, les éléments N, P, K et B sont les plus utilisés. Leur restitution se fait principalement par un apport au sol ou par pulvérisation foliaire. Mais d’autres méthodes plus ciblées, sont de plus en plus utilisées dans les plantations intensives d’oliviers comme la fertigation et l’injection au tronc de certains éléments nécessaires au bon déroulement de la culture, auxquelles l’agriculteur associe un épandage de broyat de bois de taille. L’apport de certains additifs tels que les acides aminés et les hormones s’est avéré efficace dans des situations diverses donnant une augmentation substantielle de rendement. L’établissement d’un programme de fertilisation est basé principalement sur l'objectif de production, c.-à-d. ciblant un rendement bien déterminé. Mais le diagnostic foliaire reste de première importance afin de corriger ce programme. En Tunisie, si la technique de fertilisation classique semble de plus en plus être supplantée par la fertigation et l’application foliaire d’engrais dans les plantations intensives, ces dernières techniques ne sont pas encore maîtrisées du fait de l’absence de normes propres à la Tunisie en adéquation avec le potentiel de production des variétés utilisées et des conditions environnementales. Les recherches actuelles ont permis de mettre en place pour certains modes culturaux des guides et des normes pour les principales variétés d’olivier. En intensif, la diversité des conduites, des variétés, des conditions de culture rendent difficiles l’élaboration de calendriers de références. Cet ouvrage est destiné à l’oléiculteur averti et au cadre technique concerné par la culture intensive irriguée de l’olivier. Les outils nécessaires pour assurer une gestion optimale de l’oliveraie y sont présentés. On y trouve, une revue bibliographique, des résultats de recherches obtenus en Tunisie et autour du bassin Méditerranéen relatifs aux méthodes conventionnelles et non conventionnelles de fertilisation de l’oliveraie, des applications et des procédures de calcul des paramètres de la fertigation qui font l’originalité de ce document et à partir desquelles l’utilisateur peut s’inspirer pour l’établissement d’un programme de fertigation propre à sa plantation. Mots clés : olea europea, éléments nutritifs, exportations, programme de fertilisation, fertigation.
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Olive is a very important and useful fruit species that is cultivated economically in the Mediterranean regions. Yield and qual-ity effects of olive oil and olive fruits are increased by many methods, one of them is fruit thinning. Fruit thinning is an application to control periodicity as well as increasing fruit yield and quality in olive cultivation. In addition to olives, it is currently applied in apricots, peaches, apples and pears. In recent years, potassium salt of naphthalene acetic acid (K-NAA) started to be used intensively in thinning of various fruit crops. In this study, the effects of chemical fruit thinning by using naphthalene acetic acid as potassium salt (K-NAA) on fruit yield and quality of the table olive varieties Domat, Gemlik and Memecik was determined. NAA was applied at 120, 160 and 200 ppm at 12, 16 and 20 days after full bloom, respectively, and at 100, 120 and 150 ppm at 3 - 5 mm fruit length. It was determined that 160 ppm at post-bloom and 120 ppm at fruitlet stage gave the highest increase in yield. The highest yield was obtained from Memecik and the lowest yield from Gemlik. In terms of quality parameters such as fruit weight (g), flesh/pip ratio (%), yield per unit trunk sectional area, fruit width (mm), and fruit length (mm), 160 ppm at post-bloom and 120 ppm at fruitlet stage gave the best results. This research is very important as it is a method to reduce alternate bearing and to increase yield and quality in olive.
Article
Full-text available
Olive is a very important and useful fruit species that is cultivated economically in the Mediterranean regions. Yield and qual-ity effects of olive oil and olive fruits are increased by many methods, one of them is fruit thinning. Fruit thinning is an application to control periodicity as well as increasing fruit yield and quality in olive cultivation. In addition to olives, it is currently applied in apricots, peaches, apples and pears. In recent years, potassium salt of naphthalene acetic acid (K-NAA) started to be used intensively in thinning of various fruit crops. In this study, the effects of chemical fruit thinning by using naphthalene acetic acid as potassium salt (K-NAA) on fruit yield and quality of the table olive varieties Domat, Gemlik and Memecik was determined. NAA was applied at 120, 160 and 200 ppm at 12, 16 and 20 days after full bloom, respectively, and at 100, 120 and 150 ppm at 3 - 5 mm fruit length. It was determined that 160 ppm at post-bloom and 120 ppm at fruitlet stage gave the highest increase in yield. The highest yield was obtained from Memecik and the lowest yield from Gemlik. In terms of quality parameters such as fruit weight (g), flesh/pip ratio (%), yield per unit trunk sectional area, fruit width (mm), and fruit length (mm), 160 ppm at post-bloom and 120 ppm at fruitlet stage gave the best results. This research is very important as it is a method to reduce alternate bearing and to increase yield and quality in olive.
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Olive (Olea europaea) demonstrates a high tendency toward alternate fruit production, with significant negative consequences on the industry. Fruit load is one of the main cause-and-effect factors in the phenomenon of biennial bearing, often disrupting the balance between reproductive and vegetative processes. The objectives of the present study were to identify the time range during which heavy fruit load reversibly interrupts the reproductive processes of the following year. The linkage between timing of fruit removal, vegetative growth, return bloom, and fruit yield was studied. Complete fruit removal in cv. Coratina until about 120 days after full bloom (August 15) caused an immediate resumption of vegetative growth. The new shoots grew to twice the length of those on trees that underwent later fruit removal. Moreover, a full return bloom, corresponding with high subsequent yields, was obtained by early fruit removal, while poor or no bloom developed on late-defruited or control trees. Thus, the critical time to affect flowering and subsequent fruiting in the following year by fruit thinning occurs in olive trees even weeks after pit hardening—much later than previously suggested. Furthermore, the data indicate that flowering-site limitation, due to insufficient or immature vegetative growth during the On-year, is a primary factor inducing alternate bearing in olive.
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Flower bud induction in the olive is a long lasting process, influenced by a number of factors, both internal and external to the tree. Research results seem to confirm the hypothesis of a two-step induction, eventually leading to the onset of flower bud differentiation, which appears to be started at the end of autumn. The paper examines the various aspects of this important issue in olive flower biology, by reviewing a large number of research papers produced over almost a century.
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In the article “Effect of Light Intensity and Carbohydrate Reserves on Flowering in Olive” by G.W. Stutte and G.C. Martin ( J. Amer. Soc. Hort. Sci . 111:27–31, Jan. 1986), the following correction should be noted. On p. 28, under Materials and Methods, the sentence “The 80% methanol insoluble materials were suspended in saturated CaSO 4 at pH 12.0 and boiled …” should read “The 80% methanol insoluble materials were suspended in saturated CaOH at pH 12.0 and boiled …”.
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The effect of different N forms on the growth of olive seedlings in the greenhouse was studied. KNO3, NH4NO3 and (NH4)2SO 4 at different concentrations, as well as two types of substrates, sterile sand and a sand-peat mixture (1: 1), were tested. In sterile sand, with N concentrations higher than 5 mM, serious damage was observed in the plants, so concentrations of 3, 4 and 5 mM of N were used for each N salt. N-NH 4 treatments resulted in a significantly higher growth compared to KNO3 treatment. Using the peat- sand substrate and the N concentrations described above, seedling growth was higher than in sterile sand, but no differences among treatments were observed. However, the peat:sand substrate allowed application of higher N concentrations and using NH 4NO3 differences in growth were obtained, reaching the best results with 14-28 mM.