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Dormancy release dynamics in olive tree (Olea europaea L.) reproductive buds as affected by cold accumulation, tree bearing status, and budburst temperature was studied under natural and controlled conditions, using both cuttings and container- and field-grown plants. The chilling necessary for dormancy release was acquired at different times within the bud population, presenting a progressive pattern of reproductive budburst. Once sufficient chilling is accumulated, 20 °C is a suitable temperature for reproductive budburst, although higher temperature, e.g., 30 °C, during dormancy release can inhibit budburst. While the bearing status of trees determined the amount of return bloom, dormancy release followed a similar pattern for previously bearing and non-bearing trees. Concurrent with investigating budburst factors, the use of shoot cuttings was tested as a method for olive dormancy release studies by contrasting with results from whole trees. It was found it to be valid for studying reproductive budburst, thus providing a useful method to screen chilling requirements in cultivar evaluation and the breeding programs currently ongoing in this species. However, the method was not valid for vegetative budburst, with varying results between cuttings and the whole plant. [ABSTRACT FROM AUTHOR]

Super high-density (SHD) olive orchards are rapidly expanding since the first plantation was set up in Spain in the 1990s. Because there are no long-term studies characterizing these systems, it is unknown if densities above a certain threshold could trigger competition among fully-grown trees, compromising their development. Over 14 years we have evaluated the performance of the major olive cultivars currently planted in SHD systems ("Arbequina," Arbequina IRTA-i.18, "Arbosana," "Fs-17," and "Koroneiki") and nine SHD designs ranging from 780 to 2254 trees ha-1 for the cultivar "Arbequina." Remarkably, the accumulated fruit and oil production of the five cultivars increased linearly over time. Our data indicated the favorable long-term performance of the evaluated cultivars with an average annual oil production of 2.3 t ha-1. Only "Fs-17" did not perform well to the SHD system in our conditions and it yielded about half (1.2 t ha-1) of the other cultivars. In the density trial for "Arbequina," both fruit and oil accumulated production increased over time as a function of tree density. Thus, the accumulated oil yield ranged from 16.1 t ha-1 for the lowest density (780 trees ha-1) to 29.9 t ha-1 for the highest (2254 trees ha-1). In addition, we note that the accumulated production per surface unit showed a better correlation with the hedgerow length than the tree density. Thus, the current planting designs of SHD olive orchards can be further improved taking this parameter into account. Despite observations that some irregular patterns of crop distribution have arisen, our olive hedgerows are still fully productive after 14 years of planting. This result contradicts previous experiences that showed declines in production 7 or 8 years after planting due to high vigor, shading, and limited ventilation. [ABSTRACT FROM AUTHOR]

Olive ( Olea europaea ssp. europaea) is the most important oil fruit crop in temperate areas, but the origin of the cultivated olive remains unclear. The existence of one or several domestication events in the Mediterranean Basin ( MB) is still debated., We analyzed a dataset of 387 cultivated and wild accessions that were genotyped at 25 simple-sequence repeat ( SSR) loci. The sample represented genetic diversity at the geographic extremes of the MB. We inferred relationships among samples and also applied approximate Bayesian computation to estimate the most probable demographic model of our samples., Cultivated olives clustered into three different gene pools (Q1, Q2 and Q3), corresponding loosely to the west, central and eastern MB, respectively. Q1 consisted primarily of accessions from southern Spain, retained the fingerprint of a genetic bottleneck, and was closely related to accessions from the eastern MB. Q2 showed signs of recent admixture with wild olives and may derive from a local domestication event in the central MB., Overall our results suggest that admixture shaped olive germplasm and perhaps also local domestication events. [ABSTRACT FROM AUTHOR]

Olive is one of the most ancient crop plants and the World Olive Germplasm Bank of Cordoba (WOGBC), Spain, is one of the world's largest collections of olive germplasm. We used 33 SSR (Simple Sequence Repeats) markers and 11 morphological characteristics of the endocarp to characterise, identify and authenticate 824 trees, representing 499 accessions from 21 countries of origin, from the WOGBC collection. The SSR markers exhibited high variability and information content. Of 332 cultivars identified in this study based on unique combinations of SSR genotypes and endocarp morphologies, 200 were authenticated by genotypic and morphological markers matches with authentic control samples. We found 130 SSR genotypes that we considered as molecular variants because they showed minimal molecular differences but the same morphological profile than 48 catalogued cultivars. We reported 15 previously described and 37 new cases of synonyms as well as 26 previously described and seven new cases of homonyms. We detected several errors in accession labelling, which may have occurred at any step during establishment of plants in the collection. Nested sets of 5, 10 and 17 SSRs were proposed to progressively and efficiently identify all of the genotypes studied here. The study provides a useful protocol for the characterisation, identification and authentication of any olive germplasm bank that has facilitated the establishment of a repository of true-to-type cultivars at the WOGBC. [ABSTRACT FROM AUTHOR]

Narrow hedgerows system (NHS) is a new concept of olive orchards characterized by minimum labor requirements, continuous mechanical harvesting, early bearing, high yield, and olive oil quality. In this work, the variability of phenolic composition of virgin olive oils (VOOs) was studied in three cultivars (Arbequina, Arbosana, and Sikitita), two planting systems (NHS: 1975 trees/ha and intensive system (IS): 333 trees/ha) and different harvesting dates (1 October and 26 November for the three cultivars; and three additional dates for the new olive Sikitita: 16 and 29 October; and 12 November). Phenolic compounds were extracted from the obtained VOOs by liquid-liquid extraction with 60:40 v/v methanol/water. The resulting hydroalcoholic extract was analyzed by liquid chromatography - diode-array detector - fluorescence detection (LC-DAD-FD) for individual phenols separation-quantification. Significant differences among genotypes were found for some individual phenols at the first harvesting date. At the second harvesting date, significant differences were found between genotypes and between planting systems ( p<0.05). According to the obtained results, the new Sikitita should be harvested at the beginning of the ripening period for obtaining VOO with high phenolic content. Finally, a global agronomic and oil compositional evaluation in NHS of the new cultivars bred specifically is needed for this new olive growing system. Practical applications: Narrow hedgerow is a new very high density (>1500 trees/ha) olive planting system associated to overhead vineyard harvesters that is increasingly used as it reduces drastically both labor and time needed to harvest the crop. This study focuses on the comparison of the content of phenolic compounds in olive oils originated from narrow hedgerow system and intensive system. The results can be used to determine the best time for harvesting the new olive Sikitita, recently selected for narrow hedgerow system, in order to obtain an olive oil with high phenolic content. [ABSTRACT FROM AUTHOR]

BACKGROUND: The progressive transformation of olive growing and the increasing demands for high-quality monovarietal virgin olive oil (VOO) have triggered interest in olive breeding programs, in which the evaluation of the new genotypes is the basis for obtaining new olive cultivars. In this work, the phenolic composition of VOOs from two progenies from crosses between 'Arbequina', 'Arbosana' and 'Sikitita' has been evaluated along two years. RESULTS: A higher degree of variation was observed in segregating population as compared to genitors. The results also showed that the variability within crosses constitutes the major contribution to total variance for all considered parameters (>92% of total sum of squares). All compounds under study were present in oils obtained in both years; however, clear differences in their concentrations were observed between years. CONCLUSION: Olive breeding can indeed provide genotypes that produce oils with improved phenolic profiles as compared to traditional cultivars. In addition, the data showed that selection as a function of tyrosol content could be achieved in only one crop year. Finally, p-coumaric acid was the unique component able to discriminate between both crop years under study. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The evaluation and characterization of segregating populations is a critical step in olive breeding programs. In this work, phenolic profiles of virgin olive oils (VOOs) from segregating populations obtained by cross breeding in Cordoba (Spain) have been evaluated. Genotypes obtained from open pollination of the cultivar Manzanilla de Sevilla, and from crosses between the cultivars Arbequina × Arbosana, Picual × Koroneiki and Sikitita × Arbosana were tested. The phenolic composition was determined after liquid-liquid extraction with 60:40 v/v methanol-water and subsequent chromatographic analysis with ultraviolet (UV) detection of both absorption and fluorescence in a sequential configuration. Results for all studied compounds showed high degree of variability between genotypes, with a higher range of variation than the observed for the genitors. Most of the observed variability was attributable to differences in genotypes within crosses rather than among crosses. Some issues related to breeding strategies are discussed. Practical applications: Phenolic compounds are considered to be of paramount importance for the assessment of virgin olive oil quality due to their contribution to the nutraceutical and sensory profile of this natural food. This study focuses on the evaluation of the content of phenolic compounds in olive oils originated from cross breeding in an olive breeding program (Cordoba, Spain). This step is crucial to determine the range of variation of phenolic compounds and the selection of interesting genotypes with higher composition in total phenols or in an individual phenol targeted at a breeding program. [ABSTRACT FROM AUTHOR]

Core collections reflecting the diversity of large germplasm collections are valuable tools to conserve and evaluate the genetic resources more effectively. Three strategies using two different search algorithms were trained to develop the most representative nested core collection of the World Olive Germplasm Bank (WOGB) of Cordoba (Spain), the largest and best characterized collection of olive (Olea europaea L.) cultivars worldwide. The original dataset was composed of 378 olive accessions from 21 different countries characterized by 14 microsatellite markers (simple sequence repeats [SSRs]). Each nested core collection included five subsets representing different percentages of the base collection (5, 10, 15, 20, and 30%). The strategy maximizing the allele coverage implemented in the software Core Hunter was chosen as the best. The five subsets developed by this method captured the maximum number of alleles showing fewer significant differences in their frequencies with respect to the whole collection. Additionally, a balanced geographical composition was observed in the nested subsets in spite of the strong overrepresentation of western Mediterranean accessions present in the WOGB. The results of this study are aimed at improving both the conservation and management of olive genetic resources and the study of differential genotype × environment interactions by testing a minimum number of accessions. [ABSTRACT FROM AUTHOR]

Background and Aims Genetic characterization and phylogenetic analysis of the oldest trees could be a powerful tool both for germplasm collection and for understanding the earliest origins of clonally propagated fruit crops. The olive tree (Olea europaea L.) is a suitable model to study the origin of cultivars due to its long lifespan, resulting in the existence of both centennial and millennial trees across the Mediterranean Basin. Methods The genetic identity and diversity as well as the phylogenetic relationships among the oldest wild and cultivated olives of southern Spain were evaluated by analysing simple sequence repeat markers. Samples from both the canopy and the roots of each tree were analysed to distinguish which trees were self-rooted and which were grafted. The ancient olives were also put into chronological order to infer the antiquity of traditional olive cultivars. Key Results Only 9·6 % out of 104 a priori cultivated ancient genotypes matched current olive cultivars. The percentage of unidentified genotypes was higher among the oldest olives, which could be because they belong to ancient unknown cultivars or because of possible intra-cultivar variability. Comparing the observed patterns of genetic variation made it possible to distinguish which trees were grafted onto putative wild olives. Conclusions This study of ancient olives has been fruitful both for germplasm collection and for enlarging our knowledge about olive domestication. The findings suggest that grafting pre-existing wild olives with olive cultivars was linked to the beginnings of olive growing. Additionally, the low number of genotypes identified in current cultivars points out that the ancient olives from southern Spain constitute a priceless reservoir of genetic diversity. [ABSTRACT FROM AUTHOR]

Virgin olive oil (VOO) consumption is increasing all over the world due to its excellent organoleptic and nutraceutical properties. These beneficial traits stand from a prominent and well-balanced chemical composition, which is a blend of major (98% of total oil weight) and minor compounds including antioxidants. The main antioxidants are phenolic compounds, which can be divided into lipophilic and hydrophilic phenols. While lipophilic phenols such as tocopherols can be found in other vegetable oils, most hydrophilic phenols in olive oil are exclusive of the Olea europaea species endowing it with a chemotaxonomic interest. This review is focused on VOO antioxidant profile and, particularly, on hydrophilic phenols that are divided into different sub-families such as phenolic acids and alcohols, hydroxy-isochromans, flavonoids, secoiridoids, lignans and pigments. Analytical methods for qualitative and/or quantitative determination of these compounds are assessed. The implementation of efficient sample preparation protocols, separation techniques such as liquid chromatography, GC and capillary electrophoresis, as well as detection techniques such as ultraviolet absorption, fluorescence or MS are critical to succeed in the quality of the results. The effects of hydrophilic phenols on increasing VOO stability, its nutraceutical interest and organoleptic properties are also considered. [ABSTRACT FROM AUTHOR]

The biosynthesis of the phenolic fraction of olive fruits during ripening and the transformations occurring in this moiety during virgin olive oil (VOO) extraction are discussed in this paper. The influence of agronomical factors that can significantly affect the phenolic profile of VOO is also discussed. Particularly, it is worth emphasizing the role of genetic factors, cultivation and climatic conditions such as water availability, atmospheric temperature, altitude, health status of the fruits, alternate bearing in the olive, and some processing factors such as crushing, malaxation time and temperature or volume of water added during milling. Among these parameters, special attention has been paid to genetic factors due to the high variability observed among Olea europaea genotypes for all recorded traits. In this context, interesting experimental results have been obtained with cultivated and wild olive trees, and also with segregating populations resulting from olive breeding programs. To the authors' knowledge, reviews evaluating the influence of the main factors that contribute to the profile of hydrophilic phenols have not been previously published. The discussion concerning olive breeding programs is a major and novel aspect to be emphasized considering recent trends to obtain new olive cultivars that confer better organoleptic properties and better quality to VOO. [ABSTRACT FROM AUTHOR]

Abstract  The genetic relationships within and between wild and cultivated olives were examined and clarified in an isolated and restricted area, such as the Mediterranean island of Sardinia. Wild (21 individuals) and cultivated olive trees (22 local cultivars from a germplasm collection and 35 ancient trees) were genotyped by means of 13 SSR loci. Five cases of synonymy were observed and nine distinct genotypes were identified in the collection. Five novel genotypes were also detected among the ancient trees. Differences on the allelic composition and heterozygosity levels were found between wild and cultivated trees. Model-based clustering method classified the olive trees into two major gene pools: (a) wild genotypes and (b) local cultivars from the collection and from heritage olives. Regarding the cultivated plant material, we observed that: (a) most of the Sardinian cultivars shared the same allelic profiles with the ancient cultivated trees and (b) the majority of these cultivars and all the novel genotypes were not related to any other cultivars included in this study. These findings as well as the detection of unique alleles and a certain wild genetic background at some cultivars revealed by the Bayesian analysis may indicate their autochthonous origin. The synonymy cases found between local cultivars and Italian mainland cultivars indicate interchange of genetic material among these growing areas, suggesting thus a possible allochthonous origin. The information obtained can assist in the management of an olive collection and sheds some light on the survival of true oleasters and the origin of Sardinian cultivars. [ABSTRACT FROM AUTHOR]

Cultivar identification is a primary concern for olive growers, breeders, and scientists. This study was aimed at examining the SSR markers retrieved from the literature and currently used in olive study, in order to select those most effective in characterizing the olive accessions and to make possible the comparison of data obtained by different laboratories. Olive microsatellite profiles were assessed by four independent laboratories, which analyzed 37 pre-selected SSR loci on a set of 21 cultivars. These SSR markers were initially tested for their reproducibility, power of discrimination and number of amplified loci/alleles. Independent segregation was tested for each pair of SSRs in a controlled cross and the allelic error rate was quantified. Some of them were finally selected as the most informative and reliable. Most of the alleles were sequenced and their sizes were determined. Profiles of the reference cultivars and a list of alleles with their sizes obtained by sequencing are reported. Several genetic parameters have been analysed on a larger set of cultivars allowing for a deeper characterization of the selected loci. Results of this study provide a list of recommended markers and protocols for olive genotyping as well as the allelic profile of a set of reference cultivars that would be useful for the establishment of a universal database of olive accessions. [ABSTRACT FROM AUTHOR]

Thirty-two olive cultivar accessions from Syria, most of them obtained from collecting expeditions, were characterized by means of RAPD markers before being introduced in the World Germplasm Bank of Cordoba. A total of 79 polymorphic bands (6.1 polymorphisms per primer) out of 93 (7.1 bands per primer) were scored for the 13 primers used, corresponding to 84.9% of the amplification products. Thirty-one different genotypes were clearly discriminated. Differences were not found among the amplification profiles from different individuals of the same cultivar. Only two cases of mislabeling or errors of planting were found. Fourteen accessions corresponding to 6 homonyms were discriminated by RAPDs as different genotypes. The dendrogram obtained by RAPD analysis included three major groups. Some evidence of relationships of the Syrian accessions studied according to their geographic origin and/or diffusion was found. For instance, cultivars from the Central Syria (Tadmur/Palmyra) such as Toffahi', `Abbadi Abo Gabra'-1033, `Abo Kanani', `Shami'-1041, `Abbadi Shalal' `Adgam'-844 and `Majhol'-1013 clustered in Group 1 and 2. Six cultivars from Northern Syria clustered in Group 2. But it was not found a geographic structure for the cultivars from South and West of Syria. These results agree with the hypothesis of autochthonous origin of most of the olive cultivars. Some associations between cultivars from Central Syria and their fruit size were observed. This suggests that fruit size was a criterion of local selection in olive cultivars of this area. [ABSTRACT FROM AUTHOR]

RAPD markers were used for the study of 19 Albanian olive cultivars and two wild olives (oleasters). A total of 76 polymorphic bands (4.8 polymorphic markers per primer) out of 107 reproducible were obtained using 16 primers. The number of bands per primer ranged from 4 to 10, whereas the number of polymorphic bands ranged from 1 to 9, corresponding to 71% of the total amplification products. All the accessions could be identified by the combination of four primers: OPA-19; OPA-02; OPK-16 and OPP-19. The dendrogram, based on Jaccard's index, included three major groups according to their origin: 1) most of the cultivars from the area of Berat (South of Albania) 2) cultivars from the Centre and Centre-North of Albania and 3) cultivars from the Centre and North-West of Albania along with the oleaster from Elbasan. In order to evaluate the origin of Albanian cultivars they were compared to those diffused in other countries like Greece, Italy and Turkey, due to geographical and historical affinity among these countries, by using a one way AMOVA. Although most of the genetic diversity was attributable to differences among cultivars within each country (91.47%) significant φ-values among countries (φst = 0.085; p < 0.001) suggested the existence of RAPD phenotypic differentiation. Significant φ-values in all pairs formed by Albania with the other countries were observed. These results are consistent with the autochthonous origin of Albanian cultivars. [ABSTRACT FROM AUTHOR]