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Soil salinization is considered as one of the most important risks for agricultural soils. The objective of this experiment was to study the ecophysiological and the biochemical behaviour of two cultivars of Olea europaea L., 'Chemlali' and 'Koroneiki' under two salinity levels (100 and 200 mM NaCl) and the potential alleviation induced by gibberellic acid (GA3) foliar sprays. Salinity treatments significantly decreased photosynthetic assimilation rate and stomatal conductance compared to the control for both cultivars, but ‘Chemlali’ showed a higher resistance to increasing NaCl salinity compared to 'Koroneiki'. Leaf chlorophyll index also reduced gradually with increasing salinity concentration compared to the control. At the end of the experiment, a decrease in growth and dry matter accumulation was observed. Under high salinity stress, a significant decrease in root DW was recorded by 37% and 59% for ‘Chemlali’ and ‘Koroneiki’, respectively. High salinity stress decreased also shoot DW up to 51% for ‘Chemlali’. However, mannitol concentration increased under increasing salinity levels compared to control for ‘Chemlali’ cultivars. Interestingly, foliar application of GA3 alleviated the negative effects of salinity on ecophysiological parameters especially for ‘Koroneiki’. Indeed, GA3 improved photosynthetic assimilation up to 14% for ‘Chemlali’ and 36% for ‘Koroneiki’ compared to high salinity treatment. Both cultivars showed an increase in leaf chlorophyll index after applying GA3. Under high salinity combined with GA3, growth and dry weight were increased compared to salt stressed plants without GA3. The obtained results report that ‘Chemlali’ cultivar is more tolerant to salinity than ‘Koroneiki’ and suggest that GA3 plays an important role to reduce negative effects of NaCl salinity.

Salinity and drought stresses are critical for Phaseolus vulgaris L. growth and development. They affect plants in various ways, including tissue mineral element content. Micro- and macro-elements ...

International audience; The 'pollen test' and 'fruit set test' following controlled crossing combinations of parents are the most commonly used methods for pollination incompatibility studies in Olea europaea L. Self-incompatibility (SI), with diagnoses based on the pollen test and pollen germination, indicating self-compatibility, is not always followed by fruit set in this species. To solve this dispute, we have reconciled all observations into a new model. Mismatches between field and laboratory data and between methods are resolved by the dual-successive-screen model (DSSM) supposing two different loci for the expression of the two SI mechanisms. Pollen/stigma is controlled by diallelic SI, or DSI, inferring two G1 and G2 compatibility/incompatibility (C/I) groups for varieties, whereas pollen tubes in ovaries are controlled by poly-allelic SI or PASI with twenty C/I groups. To explain the selfing of varieties, we have suggested that some determinants in the pollen tube and stigma are unstable and degrade (DS-D for degradation of S-determinant) after three to five days, enabling some pollen tubes to avoid being rejected, hence reaching ovules. DSI and PASI in the DSSM and DS-D mechanisms, plus the andromonoecy of the olive tree, complexify SI studies. Inferences from DSSM and DS-D mechanisms in olive orchard practice are detailed.

Olive tree growth and reproduction are severely affected by temperature extremes, compromising fruit yield. In that aspect, the olive varieties &ldquo, Koroneiki&rdquo, and &ldquo, Mastoidis&rdquo, were employed in a mild cold stress experiment, imitating night frost incidents to assess their biochemical, physiological and reproductive functions in relation to genotype. The physiological performance of the stressed plants was not significantly altered, suggesting that both cultivars were well adapted to mild cold night stress. The biochemical response of the plants, regarding antioxidant enzymes, H2O2 and TBARS accumulation, confirmed that both cultivars could cope with the stress applied. The mRNA levels of the PPO gene, which participates in hydroxytyrosol biosynthesis and plant defense, were elevated after 24-h stress at 0 &deg, C, in both cultivars with &ldquo, plants exhibiting higher levels for a longer period. Three more genes involved in hydroxytyrosol biosynthesis upregulated their expression levels as a response to cold stress. The numerous plant phenology aspects measured reinforced the conclusion that both cultivars responded to the stress applied. The results of the present study may contribute to better understanding olive tree adaptive responses to low temperature events, an abiotic stress condition that is often present in an open plantation, thus assisting farmers on breeding and cultivar selection.

High relative air humidity (RH ≥ 85%) is frequent in controlled environments, and not uncommon in nature. In this review, we examine the high RH effects on plants with a special focus on stomatal characters. All aspects of stomatal physiology are attenuated by elevated RH during leaf expansion (long-term) in C3 species. These include impaired opening and closing response, as well as weak diel oscillations. Consequently, the high RH-grown plants are not only vulnerable to biotic and abiotic stress, but also undergo a deregulation between CO2 uptake and water loss. Stomatal behavior of a single leaf is determined by the local microclimate during expansion, and may be different than the remaining leaves of the same plant. No effect of high RH is apparent in C4 and CAM species, while the same is expected for species with hydropassive stomatal closure. Formation of bigger stomata with larger pores is a universal response to high RH during leaf expansion, whereas the effect on stomatal density appears to be species- and leaf side-specific. Compelling evidence suggests that ABA mediates the high RH-induced stomatal malfunction, as well as the stomatal size increase. Although high RH stimulates leaf ethylene evolution, it remains elusive whether or not this contributes to stomatal malfunction. Most species lose stomatal function following mid-term (4–7 d) exposure to high RH following leaf expansion. Consequently, the regulatory role of ambient humidity on stomatal functionality is not limited to the period of leaf expansion, but holds throughout the leaf life span.

Wood decay caused primarily by Fomitiporia mediterranea is considered to be an emerging disease for citrus and olive trees in Mediterranean countries. The pathogen cannot be currently controlled by chemicals whereas there is no available information about the source and level of resistance even for the most important cultivars where the global citrus and olive industries are based on. In the present study, five of the most significant Greek olive cultivars (Amfissis, Chalkidikis, Kalamon, Koroneiki and Mastoidis) were evaluated for their resistance to F. mediterranea by conducting artificial inoculation experiments. Disease reactions were evaluated by measuring the length of bark and wood lesions, 33 months post inoculation. Trunk sections scanning and image pixel analysis were employed to estimate the total discoloration and decay area of infected wood, whereas positive re-isolation ratio of F. mediterranea was also taken into account in resistance evaluation. Data on symptom development along with wood tissue colonization by the pathogen indicated that the resistance of olive cultivars to F. mediterranea varied significantly. Based on the cumulative stress response index (CSRI), ‘Kalamon’ and ‘Koroneiki’ were classified as resistant, ‘Chalkidikis’ and ‘Mastoidis’ as intermediately resistant, whereas ‘Amfissis’ was susceptible. Determination of lignin in trunk wood showed that the resistance of olive cultivars to F. mediterranea could be associated with their lignin content. This is the first experimental evidence of differential susceptibility responses of olive cultivars against F. mediterranea, and reveals for the first time the potential exploitation of host resistance as a promising approach in the effort to control wood decay disease of olive in practice.

The aim of the present study was to determine the short-term effects (three years) of four sustainable management systems including different carbon inputs (compost, pruning residues and cover crops, applied solely or combined) on the mineral content of soil, olive trees and weeds, on some specific groups of soil microorganisms, and on weed mycorrhizal colonization in an olive orchard compared to a conventional system involving soil tillage and only mineral forms of fertilizers. The study was performed between 2013 and 2015 in a 40-year-old olive plantation. The results showed that soil organic matter, as well as main macro- and micronutrients, were markedly improved following three years of increased biomass inputs. Data related to the mycorrhizal colonization of spontaneous weed flora and to actinobacteria, Azotobacter and proteolytic bacteria suggest favourable effects on soil biology and agro-ecosystem complexity. Sowing a mixture of winter cover crops for three successive years also contributed to soil enrichment in biological as well as mineral nutrient aspects. Adoption of the sustainable management here applied practices is in complete agreement with the European policy on the transition from a linear to a circular economy and would provide significant benefits for rural stakeholders and ecosystems in the long term.

Some imperative developed genotypes of almond (‘Tardy Nonpareil’, ‘Nonpareil’, ‘Sahand’, ‘Rabie’, ‘Azar’, ‘Shekofeh’, ‘Sefied’ and ‘Mamaei’) were utilized in two experiments for 3 years to elucidate the genotype response of almond pollen germination and tube development at various temperature levels. Pollen was subjected to pre-incubation at 10, 20, 30 or 40∘C for 24 h to reproduce temperature stress during pollen dispersal; and then in vitro cultured. In the second examination, pollen was exposed at 15, 20, 25 or 30 °C for 24 h in vitro to assess pollen reaction in state of water and supplements accessibility and to determine the ideal pollen germination and tube development temperatures for every genotype. The most elevated pre- incubation temperature treatment (40 °C) completely prevented pollen germination in “Mamaei” and ‘Sefied’, while even in the less influenced cultivars ('Shekofeh’, ‘Azar’, ‘Rabie’, ‘Sahand’, ‘Tardy Nonpareil’ and ‘Nonpareil’) germination rates were as low as 2–3%. Pre-incubation at 30 ∘C or 40 °C negatively affected pollen germination and pollen tube length. In the second experiment, in vitro pollen germination increased after incubation at 25 °C for ‘Mamaei’ (+2%), ‘Sefied’ (+3%), ‘Shekofeh’ (+3%), ‘Azar’ (+3%), ‘Rabie’ (+4%), ‘Sahand’ (+5%), ‘Nonpareil’ (+5%) and ‘Tardy Nonpareil’ (+5%) compared to the control (20∘C). At 30 ∘C, germination percent for ‘Mamaei’, ‘Sefied’, ‘Shekofeh’, ‘Azar’, ‘Rabie’, ‘Sahand’, ‘Nonpareil’ and ‘Tardy Nonpareil’ was 35, 35, 10, 15, 25, 15, 35, and 20% lower, respectively, compared to the control (20 ∘C). Pollen tube length additionally increased with incubation temperature for all of the considered genotypes. In view of the cumulative stress response index (CSRI) that was calculated for high temperature stress the developed genotypes were arranged: ‘Shekofeh’ and ‘Tardy Nonpareil’ as tolerant and ‘Nonpareil’, ‘Rabie’ and ‘Sahand’ as intermediate at 40 ∘C, while ‘Azar’, ‘Rabie’, Sahand’ and ‘Tardy Nonpareil’ as tolerant, ‘Shekofeh’ and ‘Nonpareil’ as intermediate and ‘Mamaei’ and ‘Sefied’ as sensitive at 30 °C. The observed strong genotype differentiated reaction in high and low temperature stress could be utilized by plant breeders towards producing new tolerant almond genotypes.

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.

In the present study, four Greek (Agiorgitiko, Asyrtiko, Roditis and Xinomavro) and one international (Soultanina) grapevine cultivars (Vitis vinifera L.) were screened for their resistance to Phaeomoniella chlamydospora. Artificial inoculation was carried out by drilling a hole into the trunk and injecting a concentrated conidial suspension into the vessels. Disease reactions were evaluated in an 87-day assessment period, on the basis of external symptoms (disease incidence, disease severity and mortality) and by calculating the relative areas under disease progress curves (relative AUDPC). The extension of vascular browning as well as the isolation ratio along the inoculated vine trunks were also taken into account as additional parameters for evaluating resistance. The results indicated that the resistance of grapevine cultivars to P. chlamydospora varied significantly. ‘Agiorgitiko’ and ‘Soultanina’ were susceptible, whereas ‘Asyrtiko’ and ‘Xinomavro’ were resistant; ‘Roditis’ showed an intermediate level of resistance. Cultivars’ resistance was mostly distinguished in terms of the extension of vascular browning and pathogen isolation ratio. On the contrary, the disease incidence, final disease severity, mortality and relative AUDPC provided less distinctive efficiency in resistance evaluation. The robust methodology presented here could be useful in rapid evaluation experiments for future screening programs to search and recognize natural resistant sources within grapevine genotypes against P. chlamydospora.

During recent centuries, cultivated olive has evolved to one of the major tree crops in the Mediterranean Basin and lately expanded to America, Australia, and Asia producing an estimated global average value of over USD 18 billion. A long-term research effort has been established with the long-term goal to preserve biodiversity, characterize agronomic behavior, and ultimately utilize genotypes suitable for cultivation in areas of unfavorable environmental conditions. In the present study, a combination of 10 simple sequence repeat (SSR) markers with the classification binary tree (CBT) analysis was evaluated as a method for discriminating genotypes within cultivated olive trees, while Olea europaea subsp. cuspidata was also used as an outgroup. The 10 SSR loci employed in this study, were highly polymorphic and gave reproducible amplification patterns for all accessions analyzed. Genetic analysis indicated that the group of SSR loci employed was highly informative. A further analysis revealed that two sub populations and pairwise relatedness gave insight about synonymies. In conclusion, the CBT method which employed SSR allelic sizes proved to be a valuable tool in order to distinguish olive cultivars over the traditional unweighted pair group method with the arithmetic mean (UPGMA) algorithm. Further research which will combine phenotyping characterization of olive germplasm will have the potential to enable the utilization of existing, and breeding of new, superior cultivars.

Recycling Olive Mill Wastewater (OMW) by its application on agricultural land is considered to be a sustainable practice for soil enrichment and waste management, and recent legislation permits large scale OMW recycling in Mediterranean countries. Therefore, studies on the effects of OMW application on earthworms under experimental conditions that closely resemble those occurring in the field are urgently required to facilitate the safe and ecologically friendly use of OMW at large scale. In this study, the effects of three-phase OMW liquid on the survival and growth of the earthworm Octodrilus complanatus (Duges, 1828), commonly present in olive groves, were assessed. The liquid was applied at a rate i) equal to the maximum authorized by Greek legislation for olive groves fertilization (80 m3 ha−1) and ii) half of this amount (40 m3 ha−1). The effects were tested in an indoor experiment conducted in plastic containers. The results showed no adverse effect on the survival of the earthworms over a period of 56 days post-treatment, at both application doses. The growth of earthworms, as estimated by their body weight change at 28 or 56 days post-treatment, was not negatively affected; instead, there was a relative increase seen at the higher dose (80 m3 ha−1), although the difference between the treatments was not significant. Qualitative observations indicated feeding of earthworms on the OMW liquids. Organic matter decomposition was not affected and there was no significant alteration in the soil properties, except the electrical conductivity that was increased at the higher level of OMW application. Therefore, the application of OMW liquids at the doses recommended by the legislation does not affect the survival and growth of the earthworms and is compatible with their activities to promote organic matter decomposition.

Seed (endocarp) morphology is useful for genotype discrimination and cultivar classification. Over a 20-year period, 504 olive trees (Olea europaea subsp. europaea) previously assigned to different cultivars originating from Greece (n = 37), Spain (n = 2), and Italy (n = 2) as well as one accession of Olea europaea subsp. cuspidata were evaluated employing 11 endocarp morphological markers and 9 SSR markers. A matrix of 42 morphotypes in total was subjected to classification binary tree (CBT) analysis. In addition, cultivars were fingerprinted employing 9 microsatellite (SSR) markers and placed on a similarity dendrogram. All 41 olive cultivars and one accession of Olea europaea subsp. cuspidata employed in the present study yielded different morphological profiles produced by the 11 endocarp traits. In the resulting CBT, the total reduction in error, that is, the total information in the set of all 42 morphotypes, was 100%. This meant that the set of 11 morphological characters—having 28 different states in all—was sufficient to remove all data noise and to correctly classify all examined olive cultivars. In addition, all olive cultivars were successfully discriminated by the 9 SSR markers employed. It is suggested that cultivars with large seeds—and concomitantly large fruits—are more distant from the wild forms and probably more evolved compared to cultivars with small seeds. In corroboration to the above, based on seed shape, some of the olive cultivars showed high resemblance to wild olives leading thus to the hypothesis that they were produced or selected during the early ages of olive domestication.

Olive fruit fly Bactrocera oleae (Gmelin) (Diptera: Tephritidae) infestation levels were quantified in rainfed adult olive (Olea europaea L.) (Lamiales: Oleaceae) trees of seven cultivars originating from Spain, Italy, Greece, Portugal and France to determine their relationships with fruit length, width, weight, oil and mineral element content and to investigate the effects of infestation on fruit properties. Fruit from the cultivars Koroneiki, Mastoidis, Picholine, Manzanilla, Arbequina, Branquita and Leccino was collected in November 2013 in Greece. Marked genotypic variation was observed for both total and alive fruit infestation with Manzanilla being the most susceptible and Arbequina the most resistant among the cultivars studied. Marked differences were recorded in the fruit mineral element content between the cultivars studied. B. oleae infestation was positively correlated with the fruit length, width, fresh weight, and K and Fe content. Also, B. oleae infestation caused significant changes in the P, K, Fe and Mg concentration in fruits, while an overall decreasing trend was observed for N. B. oleae infestation caused no significant changes in the fruit oil content of the studied cultivars. Results presented in this study supplemented with targeted integrated research on breeding resistant genotypes and developing improved pest control tools could contribute to important savings of resources as well as improvement of yields and food quality and safety.

Olive growing counts as one of the most significant agricultural activities in Greece, from a financial, social and ecological point of view. Modern olive culture often includes exhaustive use of the available water resources having as a result adverse effects for production cost and the environment. This paper evaluates seasonal soil moisture content at three different soil depths (10, 30, 40 cm), in relation with rainfall and irrigation in an olive cultivar “Kalamon” orchard. Our results indicate strong variation of soil moisture as affected by season and irrigation. In addition, the role of drip-irrigation on soil moisture content appears to be more significant at soil depths up to 30 cm compared to lower soil zones. Specifically, at soil depth of 40 cm the soil moisture curves close to irrigation lines seems to coincide compared to these far away from the irrigation line.

International audience; The new self-incompatibility system (SI) was presented by Saumitou-Laprade, Vernet, Vekemans et al. (2017). Evolutionary Applications based on 89 crosses between varieties in the olive tree. Four main points are not clear. We are examining here as follows: (i) the assertion that the self-incompatibility system is sporophytic was not sustained by pollen germination data; (ii) surprisingly, the new model does not explain that about one-third of pairwise combinations of olive varieties leads to asymmetric fruit setting; (iii) DNA preparation from one seed may contain two embryos, and thus, embryos should be separated before seed extraction; (iv) although effective self-fertility in olive varieties was reported by many studies, the DSI model fails to explain self-fertility in some olive varieties. Moreover, we cannot discuss result data, as science cannot be verified because variety names were encoded, this does not allow comparison of data with previous works. The DSI model on olive self-incompatibility should explain more features than the model based on four dominance levels shared by six S-alleles. Perspectives for orchard management based on this model may face serious limitations. An olive variety does not have a fifty percent chance of cross-incompatibility, but surely fewer, and thus, the sporophytic system limits fruit production. Evolutionary perspectives of self-incompatibility in Oleaceae should include data from the Jasmineae tribe that displays heterostyly SI.

The genetic relationships between and within some traditionally grown cultivars of olive tree (Olea europaea L.) in Greece (island of Crete) and in Turkey were investigated. Cultivars from Crete included ‘Koroneiki’, ‘Throubolia’ and ‘Mastoidis’, while those from Turkey included ‘Samanli’ and ‘Gemlik’. Cultivars were represented by multiple genotypes of aged trees collected from the field, each one complying with established descriptors. Representative genotypes of wild olive trees from Crete were also employed. A total of 112 genotypes were analysed, employing seven microsatellite (SSR) loci yielding a total of 81 alleles, and reaching a cumulative probability of identity of 6.73 × 10−09 with a mean observed heterozygosity of 0.852. Analysis of molecular variance significantly partitioned genetic diversity between and within cultivars, albeit with no appreciable difference between the two levels of diversity. All cultivar genotypes aggregated along single, cultivar-specific clusters, pointing to human-driven selection. The two Turkish cultivars ‘Samanli’ and ‘Gemlik’ were grouped together. The Cretan cultivar ‘Throubolia’ grouped together with the two Turkish cultivars, indicating germplasm movement across the Aegean Sea during historical times. Some gene flow was observed between the Cretan cultivars and the native wild populations (likely feral forms). SSR alleles were ranked for their efficiency in discriminating the examined materials, thus establishing a molecular key for cultivar identification. An identification process is proposed including a classification binary tree and provided a method for sorting any new unknown material purportedly originating from any of the analysed cultivars.

International audience; Self-fertility is largely decreased and even prevented by various mechanisms because, broadly, it causes inbreeding depression, although some species have retained self-reproduction regimes. Species of plants that display the self-incompatible sporophytic type of self-incompatibility may rarely self-pollinate. It is only possible in the absence of foreign compatible pollen. In the olive tree with a sporophytic mechanism, we will show that three co-dominant S-alleles R1, R3 and R5 do not lead to the same level of self-fertility. All varieties that carry R1 are less self-fertile than those that carry R5, whatever the other S-alleles, while those carrying R3 are intermediate. S-allele pair-wise combinations that differ by two or three levels of dominance, and not the other combinations allow self-fertility, and moreover each S-allele R1, R3 and R5 decreases, maintains and enhances the self-fertility rate, respectively.

The present three-year study aimed to (1) determine the number of flowers per inflorescence, (2) determine the proportion of hermaphrodite flowers and (3) investigate the genetic and environmental components of self-incompatibility through controlled pollination trials, followed by microscopic observation of in vivo pollen tube growth for olive cultivars ‘ Koroneiki ’, ‘ Kalamata ’, ‘ Mastoidis ’ and ‘ Amygdalolia ’. Significant differences between cultivars and years were observed for number of flowers/inflorescence and hermaphrodite flowers percentage. The highest number of flowers was observed for ‘Kalamata’ panicles followed by ‘ Koroneiki ’, whereas the lower numbers were for ‘ Mastoidis ’ and ‘ Amygdalolia ’. The highest percentage of hermaphrodite flowers was observed for ‘ Koroneiki ’, followed by ‘ Kalamata ’ while lower levels were counted for ‘ Mastoidis ’ and ‘ Amygdalolia ’. ‘ Koroneiki ’ showed a noteworthy capability (3.6–8.7% of hermaphrodite flowers) to set fruit through self pollination. Lower fruit set rates were counted for ‘ Mastoidis ’ (1.7–2.6%) and ‘Amygdalolia’ (0.5–2.4%). The lowest level of fruit set was observed for ‘ Kalamata ’ (0.4–2%). In the case of cross pollination, the highest fruit set rates were observed for ‘Koroneiki’, intermediate rates were counted for ‘ Mastoidis ’, followed by ‘ Amygdalolia ’, and the lowest levels of fruit set were counted for ‘ Kalamata ’. In the framework of the sporophytic SI system, we attributed R2R4 to ‘ Mastoidis ’ and ‘ Kalamata ’, R1R2 to ‘Amygdalolia’ and R4R6 to ‘ Koroneiki ’. Based on the results of these experiments, recommendations were released on cross pollination requirements and combinations with compatible cultivars for setting up new olive orchards to ensure high fruit sets and adequate yields.