We have developed a vision-based program to detect symptoms of Olive Quick Decline Syndrome (OQDS) on leaves of
L. infected by
, named X-FIDO (
FastIdiosa Detector for
L.). Previous work predicted ...disease from leaf images with deep learning but required a vast amount of data which was obtained via crowd sourcing such as the PlantVillage project. This approach has limited applicability when samples need to be tested with traditional methods (i.e., PCR) to avoid incorrect training input or for quarantine pests which manipulation is restricted. In this paper, we demonstrate that transfer learning can be leveraged when it is not possible to collect thousands of new leaf images. Transfer learning is the re-application of an already trained deep learner to a new problem. We present a novel algorithm for fusing data at different levels of abstraction to improve performance of the system. The algorithm discovers low-level features from raw data to automatically detect veins and colors that lead to symptomatic leaves. The experiment included images of 100 healthy leaves, 99
-positive leaves and 100
-negative leaves with symptoms related to other stress factors (i.e., abiotic factors such as water stress or others diseases). The program detects OQDS with a true positive rate of 98.60 ± 1.47% in testing, showing great potential for image analysis for this disease. Results were obtained with a convolutional neural network trained with the stochastic gradient descent method, and ten trials with a 75/25 split of training and testing data. This work shows potential for massive screening of plants with reduced diagnosis time and cost.
Olive (Olea europaea L.) is one of the first domesticated and cultivated tree species and has historical, social and economical relevance. However, its future as a strategic commodity in ...Mediterranean agriculture is threatened by diverse biotic (traditional and new/emerging pests and diseases) and abiotic (erosion, climate change) menaces. These problems could also be of relevance for new geographical areas where olive cultivation is not traditional but is increasingly spreading (i.e., South America, Australia, etc). One of the major constraints for olive cultivation is Verticillium wilt, a vascular disease caused by the soil-borne fungus Verticillium dahliae Kleb. In this review we describe how Verticillium wilt of olive (VWO) has become a major problem for olive cultivation during the last two decades. Similar to other vascular diseases, VWO is difficult to manage and single control measure are mostly ineffective. Therefore, an integrated disease management strategy that fits modern sustainable agriculture criteria must be implemented. Multidisciplinary research efforts and advances to understand this pathosystem and to develop appropriate control measures are summarized. The main conclusion is that a holistic approach is the best strategy to effectively control VWO, integrating biological, chemical, physical, and cultural approaches.
Olive (Olea europaea L. subsp. europaea var. europaea) (diploid, 2n = 46) is the only species producing edible fruits within the botanical family Oleaceae and is one of the most ancient cultivated ...plants (90,264). The genus Olea comprises some 35 species, including the wild form O. europaea subsp. europaea var. sylvestris. Olive was probably domesticated from the wild form somewhere in the Persian-Syrian region and was subsequently introduced throughout the Mediterranean Basin by ancient Mediterranean civilizations (51). Olive is a wind-pollinated, partially self-incompatible, woody, perennial tree producing ovoid-shaped, 1.5- to 3-cm-long drupe fruits that are used mainly for oil extraction but also for direct consumption after processing (183).
•The increase in CO2 concentration may offset the negative effects of climate change.•Rainfed low density orchard in dry region will be more vulnerable to climate change.•Deficit irrigation will ...improve olive orchard productivity and carbon sequestration.•Irrigation of new intensive orchard will be sustainable under climate change.•Future winter chilling is sufficient to avoid flowering anomalies or failures.
Olive orchards represent a key agricultural system with high economic and environmental prominence. Expected future climate tendencies over the Mediterranean could threaten the sustainability of such strategic tree crop. This study evaluates the productive and environmental performance of olive orchards under different climate change scenarios and management strategies across the main olive-farming regions over southern Europe using the process-based model OliveCan. Simulations were performed for low density LD (100 trees ha−1), high density HD (400 trees ha−1) and super high density SHD (1650 trees ha−1) olive orchards over baseline period (1980-2010) and future scenarios (2041–2070 and 2071–2100 for RCP4.5 and RCP8.5). Results showed that the future increase in CO2 concentration may compensate the negative effects of higher evaporative demand and diminished water supply resulting in an enhancement of water use efficiency and carbon capture potential in olive orchards. Irrigation requirement for the maximum productivity are expected to increase by 5−27%. Moreover, rainfed low density orchards will be the most vulnerable to expected climate changes, in particular in the driest areas. In fact, a decrease in yield up to 28 % with an increase in its interannual variability of 20 % is expected over the Iberian Peninsula while yield increased up to 26 % over the centre of the Mediterranean. Deficit irrigation and intensification will improve olive orchard productivity and carbon sequestration capacity. Besides, the decrease in winter chilling is not expected to be enough to produce significant flowering anomalies or failures over the study area. Even though findings of this research showed that olive orchards may benefit from future conditions, assessment of management alternatives at local scale will be a must for a better adaptability of olive orchards.
•Potassium and calcium treatments were applied to evaluate the possible alleviation of salt stress.•The treatments improved the nutritional balance in olive tree under salinity stress.•The K ...treatment at 40 mM KNO3 enhanced salt adaptive ability of olive grown under 100 and 200 mM NaCl.•The fertilization based on K and Ca for olive trees are recommended under high saline conditions.
Soil salinization increase, aggravated by the foreseen low precipitation related to climate change, is a worldwide problem causing crop yield reductions, affecting population and environmental issues due to the salt-containing low-quality water. Enhancing the salt tolerance of plants, especially crops, is an interesting and effective solution to minimize salt-related crop problems. Toward this goal, we evaluated in this study the effect of potassium (K) and calcium (Ca) application on plant growth, nutrient uptake, water status and electrolyte and potassium leakage of two-year-old potted olive plants grown under saline conditions (100 and 200 mM NaCl). Results showed that all measured parameters were affected by salinity. However, the application of K and Ca enhanced the growth parameters, improved the water status and reduced the electrolyte and K leakage, the latter reflecting a positive effect in membrane integrity. The nutritional balance was moderately improved in salt-stressed plants treated with K and Ca. The significant reduction in sodium (Na) concentration in both leaves and roots, and the enhancement of K and Ca concentration in the different plant tissues indicated that the K and Ca supply raised the Na exclusion mechanism. The largest positive effect of K was observed with 40 mM KNO3 dose at both salinity levels. Furthermore, the beneficial effect of Ca was achieved with 40 and 10 mM CaCl2 in plants grown at 100 and 200 mM NaCl, respectively. Thus, for this relatively salt-tolerant and economically important crop, K and Ca are recommended to supply in order to mitigate the harmful effects of salinity and to develop saline agriculture in, for instance, coastal saline land.
•An early water deficit increased biophenols in fruit and oil more than a late one.•An early water deficit decreased yield more than a late deficit.•Irrigation scheduling did not affect fruit set or ...return bloom.•We studied the interactions of yield, oil quality and water savings in olive.
Experiments were performed in a high-density olive orchard to compare the effect of regulated deficit irrigation (RDI) at two different phenological stages with fully-irrigated trees (FI) over two years. Stress was imposed either prior to pit hardening (RDI 1) or after endocarp sclerification during the initial phase of oil accumulation (RDI 2). Fully irrigated trees received 2277 and 1648 m3 ha−1 in 2012 and 2013, respectively, RDI 1 ones 76 and 53% of those volumes in 2012 and 2013, respectively (RDI 2 trees 48 and 67%). There were no differences in fruit set or return bloom due to the irrigation regime. At harvest differences in fruit size between FI and RDI treatments were significant only in the first year. The fruit yields of RDI 1 and RDI 2 trees were 70 and 81% of FI ones, respectively (means of two years), but the yield efficiency was similar across all treatments. The phenolic concentration in RDI 1 fruits was higher than that in fruits from trees subjected to the other water regimes. Verbascoside, 3–4 DHPEA-EDA, and oleuropein of RDI 1 fruits were higher in 2012 (only verbascoside in 2013). Oleuropein and 3–4 DHPEA-EDA of RDI treatments were higher than those of FI in 2013. Higher concentrations of biophenols were measured in oils from RDI 1 trees in both years, whereas FI and RDI 2 showed similar values. An early water stress was more effective to increase the phenolic concentration of olive oil compared with a late deficit or full irrigation.
Olive pomace is a waste produced by the olive oil industry in massive quantities each year. Disposal of olive pomace is difficult due to high concentrations of phenolic compounds, which is an ...environmental concern. However, phenolic compounds have applications in the health industry. Therefore, extraction of phenolic compounds from olive pomace has the potential to remove an environmentally hazardous portion of pomace while creating an additional source of income for farmers and producers. Using advanced technologies including Ultrasound Assisted Extraction (UAE), combined with water as an extraction solvent, has recently gained popularity. The present study outlines the optimal UAE conditions for the extraction of phenolic compounds with high antioxidant activity from olive pomace. Optimal conditions were developed using RSM for parameters power, time and sample-to-solvent ratio. Total phenolic compounds determined by Folin Ciocalteu method and total major bioactive compounds determined by HPLC as well as antioxidant capacity (DPPH and CUPRAC) were investigated. The optimal conditions for the extraction of phenolic compounds with high antioxidant activity were 2 g of dried pomace/100 mL of water at 250 W power for 75 min. UAE improved the extraction efficiency of water and yielded extracts with high levels of phenolic compounds and strong antioxidant activity.
•The polluting effluent, olive pomace, is commonly dumped in landfill.•Novel method for extraction of phenolic compounds with high antioxidant capacity.•Water was used as an extraction solvent.•Ultrasound increased the phenolic compounds in the extracts by >20%.•Antioxidant activity of the extracts increased by >10%.
Leaf structural adaptations for the reduction of water loss were examined in two olive (
Olea europaea L.) cultivars (Chemlali and Chétoui) growing under water stress conditions. Leaf measurements ...included leaf tissue thickness, stomatal density, trichome density, specific leaf area, leaf density, water relations, and gas exchange. We found considerable genotypic differences between the two cultivars. Chemlali exhibited more tolerance to water stress, with a thicker palisade parenchyma, and a higher stomatal and trichome density. Chemlali leaves also revealed lower specific leaf area and had higher density of foliar tissue and lower reduction in net CO
2 assimilation rate. The mechanisms employed by these two cultivars to cope with water deficit are discussed at the morpho-structural level. The morphological and structural characteristics of the leaves are in accordance with physiological observations and contribute to the interpretation of why the olive cv. Chemlali is more drought-tolerant than cv. Chetoui. Furthermore, from the behaviour of Chemlali plants we consider this cultivar very promising for cultivation in semi-arid areas.
In the current study, nine olive cultivars (Olea europaea L.) coined as Dolce, Aggezi, Maraki, Coratina, Koronieki, Picual, Manzanillo, Arbosana, and Arbequina cultivated in Saudi Arabia's Northern ...region (Al-Jauf) during the 2022 harvest season were identified through molecular genetic analysis. SCoT, ISSR, and SRAP, as well as two isozyme (peroxidase and polyphenol-oxidase) profiles, were used to detect the levels of genetic diversity. The SCoT primers identified a total of 46 amplified bands, while four of these primers induced seven unique markers among the nine cultivars used in this study (41.8% polymorphism). ISSR primers generated 29 amplified bands, including eight unique markers, with a 79.9% polymorphism percentage. SRAP primer combinations exhibited a total of 37 amplified bands. Four of these combinations revealed eight unique cultivar-specific markers with a 58.4% polymorphism. It was discovered that Picual and Koronieki had the highest similarity coefficient, while Manzanillo and Dolce had the lowest. These degrees of variance could result from growing performance, distinct origins, traits, and geographic patterns. The Dolce cultivar in combination with any other studied cultivars and Manzanillo with Maraki would make sense for the hybridization program because of the higher observed distances needed to obtain higher values of important characteristics.
•This investigation aimed to compare polymorphic SCoT, ISSR and SRAP techniques.•Isozyme profilling with evaluating and analyzing the genetic relationships among some olive genotypes.•Propose a subgroup of cultivars, including genetic diversity in loci groups.
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