Olive Populations Research Articles

Genetic and phenotypic evidence suggest the existence of indigenous olive population of wild var. sylvestris in the Carmel coast, southern Levant

BackgroundPopulations of Olea europaea subsp. europaea var. sylvestris, the ancestor of cultivated olives, are scattered across the Mediterranean Basin. However, after millennia of possible hybridization with cultivated varieties, the genetic identity of many of these populations remain questionable. In the southern Levant, the plausible primary domestication center of olives, many of the naturally growing olive (NGOs) are considered feral, having developed from nearby olive groves. Here, we investigated the genetic identity of NGOs population in the Carmel region, hypothesizing that their specific location, which limit anemophily, provided an opportunity for the persistence of genuine var. sylvestris.ResultsWe mapped more than 1,000 NGOs on the Kurkar ridge along the Carmel coast, within and outside the residential area of Atlit and used simple sequence repeats of 14 loci to assess the spatial genetic structure of 129 NGOs. Genetic diversity parameters and genetic distances between NGO and cultivated olives, as well as phenotypic and morphometric analyses of their oil content and pits, respectively, indicated the presence of a genuine var. sylvestris population. However, NGOs within the residential area of Atlit and old settlements showed an intermediate admix genetic structure, indicating on hybridization with local varieties, a consequence of their proximity to cultivated trees.ConclusionsIntegrating the results of genetic and phenotypic analyses we provide crucial evidence of the presence of a genuine var. sylvestris population in the southern Levant, in close geographical proximity to archaeological sites with the earliest evidence of olive exploitation in the ancient world. We supplement the results with recommendations for a conservation program that combines municipal requirements and the urgent need to preserve the largest population of var. sylvestris in the southern Levant.

Molecular analysis of olive (Olea europaea L.) in Iraq using the internal transcribed spacer (ITS) region

Olea is a genus of about 40 species in the Oleaceae family distributed in warm temperate and tropical areas of southern Europe, Africa, southern Asia, and Australia. The study aimed to use the variations in the Internal Transcribed Spacer 1 (ITS1) region to construct a phylogenetic tree for 12 Iraqi olive varieties with 15 ITS1 sequences downloaded from the NCBI database. Leaf samples were collected from 12 olive varieties grown in five geographical regions of the north of Iraq. Using the BLAST algorithm, 12 sequences were manually adjusted by chromatogram comparison and aligned with the NCBI GenBank database. Haplotype diversity ranged from zero in the Australian population to one in the Moroccan and Spanish populations. Nucleotide diversity ranged from 0.0 in the Australian population to 0.08 in the Algerian population and Tajima's D value was −0.940. Genetic differentiation values ranged from 0.0177 between Iraqi Moroccan and Iraqi Spanish populations to 0.6540 between Iraqi and Algerian populations. The average pairwise nucleotide diversity within populations was 0.9036 in Iraqi and Turkish olive populations to 0.8671 in Iraqi and Algerian populations. The phylogenetic tree formed 2 main clusters. The first cluster includes all Algerian varieties and the Iraqi varieties are grouped in second cluster. The negative Tajima test value in all populations indicates an excess of rare alleles. The high value of gene flow between the Iraqi and Australian populations may have been mediated by human transport and these varieties may have been originated from the same geographical region.

Genomic evidence of genuine wild versus admixed olive populations evolving in the same natural environments in western Mediterranean Basin.

Crop-to-wild gene flow is a mechanism process widely documented, both in plants and animals. This can have positive or negative impacts on the evolution of admixed populations in natural environments, yet the phenomenon is still misunderstood in long-lived woody species, contrary to short-lived crops. Wild olive Olea europaea L. occurs in the same eco-geographical range as domesticated olive, i.e. the Mediterranean Basin (MB). Moreover, it is an allogamous and anemophilous species whose seeds are disseminated by birds, i.e. factors that drive gene flow between crops and their wild relatives. Here we investigated the genetic structure of western MB wild olive populations in natural environments assuming a homogenous gene pool with limited impact of cultivated alleles, as previously suggested. We used a target sequencing method based on annotated genes from the Farga reference genome to analyze 27 western MB olive tree populations sampled in natural environments in France, Spain and Morocco. We also target sequenced cultivated olive tree accessions from the Worldwide Olive Germplasm Bank of Marrakech and Porquerolles and from an eastern MB wild olive tree population. We combined PCA, sNMF, pairwise FST and TreeMix and clearly identified genuine wild olive trees throughout their natural distribution range along a north-south gradient including, for the first time, in southern France. However, contrary to our assumption, we highlighted more admixed than genuine wild olive trees. Our results raise questions regarding the admixed population evolution pattern in this environment, which might be facilitated by crop-to-wild gene flow.

SEED AND LEAF CHARACTERISTICS OF OLIVE GENOTYPES COLLECTED FROM KAHRAMANMARAS REGION OF TURKEY

Because of it can be used as a table, for oil or wood and practical medicine, olive became highly valued in Mediterranean basin. Olive oil is considered more important due to its nutritional and health advantages. The olive tree can adapt to adverse soil conditions because it is not very selective in terms of soil requirements. Turkey has a very rich diversity because it is located in the homeland of olives and has been cultivated for many years. There are olive populations that show variation in tree form, leaf and fruit characteristics in different regions of Turkey. Identifying and revealing the characteristics of plants in these populations is important for their evaluation. In this study, some morphological features were determined in olive populations in Kahramanmaraş region, which has a significant diversity. Within the olive populations, seed and leaf characteristics were revealed in 44 genotypes that were visually different and over 50 years of age. Statistical differences were found between genotypes in terms of all parameters studied. The kernel weights of the genotypes varied between 0.76-0.38 g. Kernel length and width values were determined as 16.03-12.21 mm and 10.07-8.01 mm, respectively. The highest leaf length of the genotypes was 7.42 cm and the lowest 5.70 cm. Leaf widths were determined as 15.82-8.49 mm. The results revealed that there is a significant olive diversity in Kahramanmaraş region. It is important to conservation this richness and use it in breeding and genetic studies.

Hatay İli Hassa İlçesinde Bulunan Bazı Yabani (Delice) Zeytin (Olea europaea L. subps. oleaster) Genotiplerinin Çelikle Köklenebilme Durumlarının Araştırılması

Seleksiyon neticesinde elde edilmiş bazı yabani (delice) zeytin genotiplerinin köklenme performanslarının araştırılması amacıyla hazırlanan bu çalışmada, Kasım 2020 - Mart 2022 tarihleri arasında Hatay ili Hassa ilçesinde yoğun olarak bulunan yabani zeytin popülâsyonları içerisinden selekte edilen 133 genotip materyal olarak kullanılmıştır. Çalışma Hatay Zeytincilik Araştırma Enstitüsü Müdürlüğü Hassa İstasyonu İşletmesi’nde yürütülmüştür. Çalışmada köklenme materyali olarak perlit kullanılmıştır. Ortalama 25 cm ebatlarında hazırlanan çeliklerin 3 cm’lik dip kısımları 4000 ppm dozunda hazırlanmış indol butirik asit (IBA) solüsyonuna 5 sn süreyle daldırılmıştır. 25oC’ye ayarlanmış alttan ısıtmalı, sisleme üniteli, yarı otomatik seraya dikimleri gerçekleştirilmiştir. Bu şekilde 90 günü tamamlayan genotiplere ait çelikler sökülerek köklenme oranı, kök sayısı, kök uzunlukları tespit edilmiştir. Çalışma neticesinde, tüm veriler ışığında anaç olma potansiyeli yüksek olan ilk 5 anaç adayı; 917 puan ile 31.8.2.39 No’lu genotip, 860 puan ile 31.8.16.11 No’lu genotip, 798 puan ile 31.8.2.36 No’lu genotip, 797 puan ile 31.8.2.34 No’lu genotip ve 772 puan ile 31.8.16.16 No’lu genotip olmuştur.

Studies on archaeological olive fruitstones from the Archaic and Punic periods (7th–3rd century bc) of Sardinia, Italy

Recent archaeological investigations in the lagunas di Santa Giusta and Mistras, waterlogged sites in central-west Sardinia, Italy, have enabled the recovery of archaeobotanical remains, exceptional in terms of quantity and preservation, dated to the Archaic and Punic periods in the 7th–3rd century bc. Among the finds was a significant amount of Olea europaea fruitstones (endocarps), which are discussed here. The morphometric features of these fruitstones, extrapolated by image analysis, were analysed statistically and compared to modern wild olive populations and cultivars. Thanks to the image analysis, it was possible to recognize the presence of O. europaea var. sylvestris (wild olive) and O. europaea var. europaea (cultivated olive) from the Archaic and Punic periods and to make suggestions about their use. Moreover, most of the cultivated type fruitstones identified by the statistical analysis can be attributed to a group of modern Sardinian cultivars, providing new data on the origin of cultivation and use of olives in Sardinia.

Elucidation of the Origin of the Monumental Olive Tree of Vouves in Crete, Greece.

The olive tree of Vouves in Crete, is considered the oldest producing olive tree in the world with an estimated age exceeding 4000 years. In the present study, we sequenced two samples (from the bottom and the top of the tree) to elucidate the genetic relation of this ancient tree with other olive cvs as well as to gain some insights about its origin. Our results showed that both samples have different genetic origins, proving that this ancient tree has been grafted at least one time. On the basis of whole genome sequences the sample from the top of the Vouves tree showed relation of the same order than half-siblings to one accession corresponding to the present-day Greek cv ‘Mastoidis’. Nevertheless, in the framework of a microsatellite analysis it was found to cluster with the ‘Mastoidis’ samples. The Vouves rootstock (bottom sample) showed a clear grouping with the oleaster samples in a similar way to that of ‘Megaritiki’ Greek cv although it does not show any signal of introgression from them. The genomic analyses did not show a strong relation of this sample with the present-day Greek cvs analyzed in this study so it cannot be proved that it has been used as a source for cultivated olive tree populations represented by available genome sequences. Nevertheless, on the basis of microsatellite analyses, the Vouves rootstock showed affinity with two present-day Greek cvs, one “ancient” rootstock from continental Greece as well as monumental trees from Cyprus. The analysis of the impact of the variants in the gene space revealed an enrichment of genes associated to pathways related with carbohydrate and amino acid metabolism. This is in agreement with what has been found before in the sweep regions related with the process of domestication. The absence of oleaster gene flow, its old age and its variant profile, similar to other cultivated populations, makes it an excellent reference point for domestication studies.

Contrasting Genetic Footprints among Saharan Olive Populations: Potential Causes and Conservation Implications.

The Laperrine’s olive is endemic to the Saharan Mountains. Adapted to arid environments, it may constitute a valuable genetic resource to improve water-stress tolerance in the cultivated olive. However, limited natural regeneration coupled with human pressures make it locally endangered in Central Sahara. Understanding past population dynamics is thus crucial to define management strategies. Nucleotide sequence diversity was first investigated on five nuclear genes and compared to the Mediterranean and African olives. These data confirm that the Laperrine’s olive has a strong affinity with the Mediterranean olive, but it shows lower nucleotide diversity than other continental taxa. To investigate gene flows mediated by seeds and pollen, polymorphisms from nuclear and plastid microsatellites from 383 individuals from four Saharan massifs were analyzed. A higher genetic diversity in Ahaggar (Hoggar, Algeria) suggests that this population has maintained over the long term a larger number of individuals than other massifs. High-to-moderate genetic differentiation between massifs confirms the role of desert barriers in limiting gene flow. Yet contrasting patterns of isolation by distance were observed within massifs, and also between plastid and nuclear markers, stressing the role of local factors (e.g., habitat fragmentation, historical range shift) in seed and pollen dispersal. Implications of these results in the management of the Laperrine’s olive genetic resources are discussed.

Intra-varietal Morphological Diversity of Montenegrin Olive Variety ‘Žutica’ Based on Multivariate Analysis

The most important olive (Olea europaea L.) variety in Montenegro is ‘Žutica’ which represents 65% of total olive population of the coastal area, and 98% of the olive trees in the southern sub-region of Bar. A total of 42 trees of olive variety ‘Žutica’ from the coastal area was selected and evaluated of morphological and technological traits during three consecutive years (2009–2011). Analyses of a set of twenty one parameters, analysis of variance and descriptive statistics revealed significant differences among clones for majority of the studied traits. Coefficient of variation was under the range of 20% for almost all examined traits. The strongest correlations (r > 0.75; P < 0.05) were observed between parameters of inflorescence, fruit and endocarp. The highest correlation between FL was with FWE (r = 0.87), FW (r = 0.76) as well as with EL and EWE (r = 0.88), and EW (r = 0.79). These parameters are in mutual correlative dependence. PCA analyses with five principal component axes had the total cumulative variance of 75.29%, with fruit and endocarp size in PC1 and flesh and stone ratio in PC2. Cluster analyses based on 12 morphological traits divided analyzed accessions into two main clusters. The first one with 22 accessions, further divided into two main subgroups, is composed of accessions with highest fruit weight (above 3.2 and 4.0 g). The second cluster was comprised of 20 accessions, 17 of which were from the south coastal area, and exhibited lower values of inflorescence, fruit and endocarp parameters. Our results indicate considerable variability of morphological parameters which are to be studied further and proved on molecular level.

Genetic flow among olive populations within the Mediterranean basin.

BackgroundThe olive tree is a typical crop of the Mediterranean basin where it shows a wide diversity, accounting for more than 2,600 cultivars. The ability to discriminate olive cultivars and determine their genetic variability is pivotal for an optimal exploitation of olive genetic resources.MethodsWe investigated the genetic diversity within 128 olive accessions belonging to four countries in the Mediterranean Basin (Italy, Algeria, Syria, and Malta), with the purpose of better understanding the origin and spread of the olive genotypes across Mediterranean Basin countries. Eleven highly polymorphic simple sequence repeat (SSR) markers were used and proved to be very informative, producing a total of 179 alleles.ResultsCluster analysis distinguished three main groups according to their geographical origin, with the current sample of Maltese accessions included in the Italian group. Phylogenetic analysis further differentiated Italian and Maltese olive accessions, clarifying the intermediate position of Maltese accessions along the x/y-axes of principal coordinate analysis (PCoA). Model-based and neighbor clustering, PCoA, and migration analysis suggested the existence of two different gene pools (Algerian and Syrian) and that the genetic exchange occurred between the Syrian, Italian and Maltese populations.DiscussionThe close relationship between Syrian and Italian and Maltese olives was consistent with the historical domestication and migration of olive tree from the North Levant to eastern Mediterranean basin. This study lays the foundations for a better understanding of olive genetic diversity in the Mediterranean basin and represents a step toward an optimal conservation and exploitation of olive genetic resources.

Variation in seed morpho-physiological and biochemical traits of Java olive populations originated from Java, Bali, Lombok, and Timor Islands, Indonesia

Sudrajat DJ, Suwandhi I, Siregar IZ, Siregar UJ. 2018. Variation in seed morpho-physiological and biochemical traits of Java olive populations originated from Java, Bali, Lombok, and Timor Islands, Indonesia. Biodiversitas 19: 1004-1012. Java olive (Sterculia foetida L.) is one of the promising non-edible feedstocks for biodiesel production. Utilization of this tree species for plantation is limited due to knowledge gaps in many fundamental aspects of seed properties. The aim of the study was to determine the variation that may exist among java olive seed collected from Bogor, Palimanan, Tuban, Gilimanuk, Pemenang and Naioni populations, and to analyze correlations between one or many seed morpho-physiological and biochemical traits. Analysis of variance showed significant differences of seed morphological and biochemical traits, except for the germination capacity. Seed morphological traits were not significantly correlated with agro-climate factors, while some of biochemical traits revealed significant correlation with some agro-climate factors. Genotypic variance and genotypic coefficient of variation were higher for fruit length, fruit width, carbohydrate, fat, protein and oil contents, indicating higher genetic contribution on the variance of these traits. High heritability values combined with high genetic gain was found for protein content, fruit width and oil content, that revealed the characters having highly genetic origin with a good number of heritable components. Population clustering exhibited that most of the geographically distant population are genetically related. Pemenang population was found highly associated with oil content, indicating that the population have high potency to develop as the feedstocks for for biodiesel production.

The effect of the invasive Elaeagnus umbellata on soil microbial communities depends on proximity of soils to plants

AbstractInvasive plants are often associated with dense monocultures, which reduce native plant diversity. Multiple studies have shown significant impacts of dense invasive plant populations on soil microbial communities. In many cases, however, invasive plants are present in lower, non‐uniform densities. This is especially true of some woody/shrubby invaders. We studied two such populations of autumn olive: a highly invasive, nitrogen‐fixing shrub, commonly found throughout the Midwestern United States. In each population, we collected soil samples in a rectangular grid, noting the distance of each sample point to the nearest autumn olive plant, as well as the local density of autumn olive. Soils were assessed for pH, moisture, nitrogen availability, microbial community composition, and enzyme activity. We found that autumn olive significantly affected the dominant taxa of bacterial and archaeal communities, particularly ammonia‐oxidizing microorganisms, as determined by denaturing gradient gel electrophoresis of functional genes characteristic of these microbial groups. The changes in microbial communities were related to the proximity and local density of autumn olive shrubs. In most cases, the effect of autumn olive was greater than that of either pH or moisture. In contrast, microbial function (measured as enzyme activities), while non‐uniform, did not seem to be as strongly related to the presence of the invasive plant. Our findings suggest that autumn olive can affect soil microbial community composition even when it is present in relatively low densities. This should be considered when assessing remediation strategies for autumn olive‐invaded areas.

Genetic variation of naturally growing olive trees in Israel: from abandoned groves to feral and wild?

BackgroundNaturally growing populations of olive trees are found in the Mediterranean garrigue and maquis in Israel. Here, we used the Simple Sequence Repeat (SSR) genetic marker technique to investigate whether these represent wild var. sylvestris. Leaf samples were collected from a total of 205 trees at six sites of naturally growing olive populations in Israel. The genetic analysis included a multi-locus lineage (MLL) analysis, Rousset’s genetic distances, Fst values, private alleles, other diversity values and a Structure analysis. The analyses also included scions and suckers of old cultivated olive trees, for which the dominance of one clone in scions (MLL1) and a second in suckers (MLL7) had been shown earlier.ResultsThe majority of trees from a Judean Mts. population and from one population from the Galilee showed close genetic similarity to scions of old cultivated trees. Different from that, site-specific and a high number of single occurrence MLLs were found in four olive populations from the Galilee and Carmel which also were genetically more distant from old cultivated trees, had relatively high genetic diversity values and higher numbers of private alleles. Whereas in two of these populations MLL7 (and partly MLL1) were found in low frequency, the two other populations did not contain these MLLs and were very similar in their genetic structure to suckers of old cultivated olive trees that originated from sexual reproduction.ConclusionsThe genetic distinctness from old cultivated olive trees, particularly of one population from Galilee and one from Carmel, suggests that trees at these sites might represent wild var. sylvestris. The similarity in genetic structure of these two populations with the suckers of old cultivated trees implies that wild trees were used as rootstocks. Alternatively, trees at these two sites may be remnants of old cultivated trees in which the scion-derived trunk died and was replaced by suckers. However, considering landscape and topographic environment at the two sites this second interpretation is less likely.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0947-5) contains supplementary material, which is available to authorized users.

Effectiveness of a computer vision technique in the characterization of wild and farmed olives

Existing in two forms, namely the wild and the cultivated one, the olive tree (Olea europaea L.) is one of the most widespread species in the Mediterranean Basin since the sixth millennium B.C. According to the theory of a polycentric origin for domestication, mainly supported by the presence of the wild form all over the Mediterranean area, the goal of this study is to use endocarps biometric features, measured by image analysis techniques, in order to investigate the relationships among different Sardinian wild olive populations, ancient olive trees and olive cultivars. A total of 137 morphometric, colorimetric and textural characters were measured on each of the 2842 studied endocarps. The morpho-colorimetric analysis of olive endocarps proved the effectiveness of the technique to discriminate between the two currently recognized O. europaea L. varieties (var. europaea and var. sylvestris). The partial overlapping that resulted between wild and ancient olives suggests the existence of large populations characterized by a high degree of phenotypic variability. Similar results were reached for varietal discrimination, perfectly fitting with previous findings of molecular studies. Considering the phenotypic and genetic distance of cultivars from autochthonous wild olives, the allochthonous origin of local varieties is furthermore confirmed.

Machine Learning Based Classification of Microsatellite Variation: An Effective Approach for Phylogeographic Characterization of Olive Populations

Finding efficient analytical techniques is overwhelmingly turning into a bottleneck for the effectiveness of large biological data. Machine learning offers a novel and powerful tool to advance classification and modeling solutions in molecular biology. However, these methods have been less frequently used with empirical population genetics data. In this study, we developed a new combined approach of data analysis using microsatellite marker data from our previous studies of olive populations using machine learning algorithms. Herein, 267 olive accessions of various origins including 21 reference cultivars, 132 local ecotypes, and 37 wild olive specimens from the Iranian plateau, together with 77 of the most represented Mediterranean varieties were investigated using a finely selected panel of 11 microsatellite markers. We organized data in two ‘4-targeted’ and ‘16-targeted’ experiments. A strategy of assaying different machine based analyses (i.e. data cleaning, feature selection, and machine learning classification) was devised to identify the most informative loci and the most diagnostic alleles to represent the population and the geography of each olive accession. These analyses revealed microsatellite markers with the highest differentiating capacity and proved efficiency for our method of clustering olive accessions to reflect upon their regions of origin. A distinguished highlight of this study was the discovery of the best combination of markers for better differentiating of populations via machine learning models, which can be exploited to distinguish among other biological populations.

An ecological and evolutionary perspective on the parallel invasion of two cross-compatible trees.

Invasive trees are generally seen as ecosystem-transforming plants that can have significant impacts on native vegetation, and often require management and control. Understanding their history and biology is essential to guide actions of land managers. Here, we present a summary of recent research into the ecology, phylogeography and management of invasive olives, which are now established outside of their native range as high ecological impact invasive trees. The parallel invasion of European and African olive in different climatic zones of Australia provides an interesting case study of invasion, characterized by early genetic admixture between domesticated and wild taxa. Today, the impact of the invasive olives on native vegetation and ecosystem function is of conservation concern, with European olive a declared weed in areas of South Australia, and African olive a declared weed in New South Wales and Pacific islands. Population genetics was used to trace the origins and invasion of both subspecies in Australia, indicating that both olive subspecies have hybridized early after introduction. Research also indicates that African olive populations can establish from a low number of founder individuals even after successive bottlenecks. Modelling based on distributional data from the native and invasive range identified a shift of the realized ecological niche in the Australian invasive range for both olive subspecies, which was particularly marked for African olive. As highly successful and long-lived invaders, olives offer further opportunities to understand the genetic basis of invasion, and we propose that future research examines the history of introduction and admixture, the genetic basis of adaptability and the role of biotic interactions during invasion. Advances on these questions will ultimately improve predictions on the future olive expansion and provide a solid basis for better management of invasive populations.

Rattus management is essential for population persistence in a critically endangered passerine: Combining small-scale field experiments and population modelling

Invasive species are a major threat for island biodiversity, causing species decline and extinction globally. Of all invasive mammals rats are one of the most detrimental and have been the target of numerous control and eradication programmes. In Mauritius rats have contributed to the extinction of 50% of the island's fauna and are thought to be the main threat to the endemic Mauritius olive white-eye (Zosterops chloronothos), a critically endangered passerine. Assessing the impact of rats and suitable control strategies is often problematic in such cases because of the lack of replicate populations for experiments. Here, we illustrate how to overcome this issue by combining a small-scale rat management experiment on olive white-eyes with demographic models that provide estimates of the potential effects of management on vital rates and population growth. We established poison and trapping grids within breeding territories, and show that rat management significantly decreased rat abundance and increased nesting success. An individual-based stochastic simulation model suggested that rat control could produce a 5–6 fold increase in the annual productivity of female olive white-eyes, which in turn would be sufficient to stabilise population growth. In the absence of rat management, our analysis suggests the olive white-eye population will decline by about 14% per annum. By combining low cost field experiments with widely available demographic models we highlight the value of targeted, effective rat management techniques for both short and long-term population management in threatened passerines.

Evaluation of genetic diversity in cultivated (O. europaea subsp. europaea L. ssp. europea var. europaea) and wild olives (Olea cuspidata Wall) using genome size and RAPD markers

Olive is one of the most important horticultural plants having wild and cultivated forms. Information on the genetic diversity attendant in cultivated and wild olives is quite important to augment breeding program on olive tree. The present study reports genome size (C-value) and RAPD analysis of four cultivated olive genotypes (O. europaea subsp. europaea var. europaea) and three wild olive (Olea cuspidate) populations from different regions of Iran. Determination of the relative C-value (RC) and 2C value of the wild and cultivated olives showed that the RC value varies from 1.89 pg in Dezful cultivar cultivated in Safiabad region to 2.28 pg in Olea cuspidate growing in Baghe-Mansouri locality. Similarly 2C DNA content varied from 5.36 pg in Dezful cultivar cultivated in Safiabad region to 6.2 pg in Olea cuspidate growing in Baghe-Mansouri locality. ANOVA followed by LSD test showed a significant difference in DNA content of the genotypes studied indicating quantitative differences in genetic material, although all of them are diploid with 2n = 2x = 46. RAPD analysis of the seven olive populations showed intra and inter genotype variations. The presence of polymorphic bands /loci observed in olive species studied indicates the presence of genetic polymorphism in these species, which may be used in olive breeding.

Russian Olive Fruit Production in Shelterbelt and Riparian Populations in Montana

Russian olive (Eleagnus angustifolia) is a conflict tree species: it is invasive in riparian habitats throughout the western U.S., but is often considered desirable in uplands of the northern Great Plains (e.g. soil stabilization and providing windbreaks). Desirable and invasive populations of Russian olive have different demographic and ecological characteristics that will affect the persistence of biological control organisms. Current biological control development for Russian olive focuses on fruit-reducing agents anticipated to slow or halt the spread of invasion without causing individual tree mortality. Population demography data collected from upland and riparian populations of Russian olive from 2010-2012 show that fruit production is more variable among upland populations, with zero or few trees setting fruit in 2010. A greater degree of abiotic stress in upland populations (lower precipitation/water table, and higher temperature) may cause more variable fruit production compared to riparian populations. The spatial and temporal scale of resource availability (i.e. fruit production) differs between upland and riparian populations. A biological control agent would require very high dispersal ability to persist in upland populations with greater spatial separation and more variable fruit production. In contrast, agent dispersal capacity may be less important in riparian populations with lower spatial separation and less variable fruit production. Because rivers differ in degrees of spatial variability, we may expect differences in biological control agent persistence among drainages. Using ecological and demographic data of host resources with models of herbivore population persistence could provide a novel approach to resolving conflicts in invasive species management.

Sequence analysis of single-copy genes in two wild olive subspecies: nucleotide diversity and potential use for testing admixture.

The wild olive distribution extends from the Mediterranean region to south Asia and Austral Africa. The species is also invasive, particularly in Australia. Here, we investigated the sequence variation at five nuclear single-copy genes in 41 native and invasive accessions of the Mediterranean and African olive subspecies. The nucleotide diversity was assessed and the phylogenetic relationships between alleles were depicted with haplotype networks. A Bayesian clustering method (STRUCTURE) was applied to identify the main gene pools. We found an average of 18.4 alleles per locus. Native Mediterranean and African olives only share one allele, which testifies for ancient admixture on the Red Sea hills. The presence of divergent alleles in the Mediterranean olive, as well as the identification of two main genetic clusters, suggests a complex origin with two highly differentiated gene pools from the eastern and western Mediterranean that recently admixed. In the invasive range, relatively high nucleotide diversity is observed as a consequence of the introduction of alleles from two subspecies. Our data confirm that four invasive individuals are early-generation hybrids. Finally, the utility of single-copy gene sequences in olive population genomic and phylogenetic studies is briefly discussed.