Search Results (146)

Almond (Prunus dulcis (Mill.) D.A. Webb) is one of the most economically important nut crops worldwide, valued for its nutritional properties and adaptability to diverse agroecological environments. This review summarizes current knowledge on almond domestication, genetic diversity, production trends, and improvement strategies, with a focus on drought tolerance under climate change. Archaeobotanical and molecular evidence indicate central Asia and the eastern Mediterranean as key centers of origin, where recurrent introgression from wild Prunus species contributed to the high genetic variability of cultivated almond. Global production trends reveal increasing challenges due to prolonged drought, climate variability, and rising water and energy costs, particularly affecting major producers such as the United States. Mediterranean regions are transitioning from traditional low-density orchards to intensive systems, where cultivar and rootstock choice are crucial for sustainability. Self-fertile and late-blooming cultivars improve yield stability, while interspecific hybrid rootstocks enhance water use efficiency and tolerance to drought and poor soils. Drought stress impacts almond physiology and yield, although moderate deficit irrigation can maintain productivity and improve kernel quality. Future improvement relies on germplasm conservation, marker-assisted selection, and genomic tools to develop climate-resilient cultivars integrated with sustainable water management strategies. Full article

Background: Gametophytic self-incompatibility (GSI) controlled by a multi-allelic S-locus, is inferred to have evolved before the spilt of the Rosidae and Asteridae. In Rosaceae, molecular characterisation of the genera Prunus and Malus reveals that different numbers of genes determine GSI specificity. In Prunus, one pistil-expressed (female) gene and one pollen (male) gene encode a series of stylar RNase (S-RNase) alleles and series of S-haplotype-specific F-box (SFB) alleles, respectively, thereby determining the female and male specificity. In contrast, in Malus, GSI specificity is controlled by one pistil gene and multiple pollen genes, known as SFB-brothers (SFBBs), which encode a series of S-RNase and SFBB alleles, respectively, within the S-locus, to determine female and male specificity. Despite these advances, the molecular mechanisms of these two genera remain largely unknown, and it is still uncertain how GSI originated or which factors shape the orientation, evolution, and function of the S-locus. Methods: Therefore, in this study, we applied a holistic integrative approach combining analyses of gene distribution, phylogenetic inference, biogeographic history, selective pressures, co-evolution, and protein interaction networks across three Prunus genomes (P. dulcis, P. persica, and P. avium) to elucidate the evolutionary forces driving sexual diversity and molecular specificity of GSI within the Rosaceae. Results: Our results indicated that rapid diversification of the Prunus S-locus was due to the repeated duplication events in the SFB, SLF, and S-RNase genes producing both functional and non-functional duplicates. Conclusions: In Rosaceae, diversity of S-locus mechanisms is shaped by lineage-specific selection, functional divergence, co-evolution of pistil- and pollen-expressed components, dynamic protein-interaction networks, geological history and climatic change. Full article

Climate change influences the agronomic behaviour of fruit trees. It is necessary to determine which cultivars adapt best to conditions in which water supplies are becoming increasingly scarce. This study analyses different phenological, morphological, physiological, agronomic and productive parameters to evaluate water stress tolerance in six late-blooming almond cultivars widely grown in Spain (‘Ferragnès’, ’Francolí’, ‘Masbovera’, ‘Glorieta’, ’Guara’ and ‘Lauranne’). Two different plots were analysed: one under regulated deficit irrigation, at Les Borges Blanques, Lleida, with a water deficit (146.2 mm/year) and the other under rainfed conditions, at Mas Bové, Constantí, Tarragona, with a water deficit (284.5 mm/year). Parameters, including an increase in canopy volume, leaf-to-air thermal gradient, and slope between leaf water potential and level of leaf saturation, have proven to be good indicators of resistance to water stress. Yield variation and leaf temperature variation between rainfed and irrigated conditions also perform quite well. An assessment of leaf chlorophyll content, measured using SPAD-502, suggested the presence of a collateral effect resulting from the opacity of the biomass, as well as to chlorophyll-related cuticular colouring. Finally, under the experimental conditions, ‘Guara’ and ‘Masbovera’ proved the most resistant cultivars; ‘Glorieta’ and ‘Francolí’ exhibited an intermediate level, and ‘Lauranne’ and ‘Ferragnès’ were the least resistant cultivars. Full article

Adventitious shoot regeneration is an essential prerequisite for the application of biotechnological tools such as CRISPR-Cas in woody fruit crops. Nonetheless, many Prunus species exhibit strong recalcitrance to in vitro regeneration. Light quality has emerged as an important environmental factor influencing morphogenic responses under in vitro conditions. In this study, the effect of different LED light spectra on adventitious shoot regeneration was evaluated in three peach-related genotypes: the commercial peach cultivar ‘Siroco 5’ (Prunus persica L.) and the hybrid rootstocks ‘GF677’ and ‘Garnem’ (P. persica × P. dulcis). Callus explants derived from the basal region of in vitro proliferation cultures were exposed for 30 days to five LED light treatments: white (control), blue, red + far-red, mixed (red + far-red + blue), and sequential LED light. Regeneration efficiency was assessed through the frequency of organogenic callus formation (FOC), the number of regenerated shoots per explant, the organogenic rate, and the fresh weight of the regenerated explants. While FOC was consistently high across genotypes and light treatments, shoot regeneration was significantly influenced by both genotype and light spectrum. The hybrid rootstocks exhibited a higher regeneration capacity than the commercial cultivar under most conditions. Red + far-red LED light promoted the highest regeneration efficiency across all of the genotypes, particularly enhancing shoot regeneration and fresh weight in ‘Siroco 5’. These results demonstrate that LED light spectrum modulation, especially red + far-red, is an effective strategy to optimize adventitious shoot regeneration in peach cultivar and hybrid rootstock genotypes, providing a robust basis for future applications in micropropagation and genetic improvement programs. Full article

Heat and high-irradiance stress increasingly threaten almond production in Mediterranean environments, where rising temperatures and prolonged summer droughts impair photosynthetic performance and yield. This study evaluated the effectiveness of three mineral-based shielding materials: kaolin, basalt powder, and zeolite. We hypothesized that the foliar application of reflective mineral materials would reduce leaf temperature, enhance photosynthetic efficiency, and improve yield without altering nut nutraceutical quality. A two-year field experiment (2024–2025) was conducted using a randomized block design with four materials (untreated control, kaolin, basalt powder, and zeolite). Physiological traits (gas exchange, chlorophyll fluorescence, leaf temperature, and SPAD index), morpho-biometric and biochemical parameters, and yield components were assessed. Kaolin and basalt powder significantly lowered leaf temperature (−1.6 to −1.8 °C), increased stomatal conductance and net photosynthesis, and improved photochemical efficiency (Fv′/Fm′) and electron transport rates. These treatments also enhanced drupe weight, kernel dry matter, and productive yield (up to +32% compared with the control). Zeolite produced positive but less prominent effects. No significant differences were detected in fatty acid profile, total polyphenols, or antioxidant capacity, indicating that the materials did not affect almond nutraceutical quality. Principal component analysis confirmed the strong association between kaolin and basalt powder and improved eco-physiological performance. Overall, mineral shielding materials, particularly kaolin and basalt powder, represent a promising, sustainable strategy for enhancing almond orchard resilience under Mediterranean climate change scenarios. Full article

Polystigma amygdalinum the causal agent of Red Leaf Blotch (RLB), is responsible for one of the most important foliar diseases affecting almond [Prunus dulcis (Miller) D.A. Webb] in the Mediterranean Basin and the Middle East. The study is aimed at improving knowledge on RLB epidemiology and the role of environmental conditions in disease development. Field monitoring was conducted from 2022 to 2025 in three almond orchards located in Apulia (southern Italy) and characterized by different microclimatic conditions. A total of 39 cultivars, including Apulian local germplasm and international cultivars (‘Belona’, ‘Genco’, ‘Guara’, ‘Ferragnès’, ‘Filippo Ceo’, ‘Lauranne^® Avijor’, ‘Soleta’, and ‘Supernova’), were evaluated. Symptoms occurred from late spring to summer, resulting particularly severe on ‘Guara’ and ‘Lauranne^® Avijor’, whereas ‘Belona’, ‘Ferragnès’, ‘Genco’, and ‘Supernova’ exhibited the highest tolerance. To our knowledge, this is also the first report of RLB tolerance by ‘Filippo Ceo’, ‘Ficarazza’, ‘Centopezze’, and ‘Rachele piccola’ representing potential genetic resources for breeding programs. Moreover, these findings reinforced previous observations proving that RLB was less severe on medium-late and late cultivars. Disease incidence varied significantly among sites and years and was strongly associated with increased rainfall, higher relative humidity, and mild temperatures recorded in November, influencing disease occurrence in the following growing season. P. amygdalinum was consistently detected by qPCR in all RLB-affected tissues and, in some cases, from mixed early RLB + Pseudomonas-like symptoms. From some leaves with early RLB symptoms, P. amygdalinum was also successfully isolated in pure culture. Overall, our results provide clear evidence that P. amygdalinum is the sole fungal pathogen consistently associated with typical RLB symptoms in Apulia (southern Italy) and highlight important cultivar-dependent differences. Its frequent molecular detection in leaves showing atypical or mixed symptoms suggests unresolved epidemiological aspects requiring further investigation. Full article

Diaporthe amygdali Delacr. is a phytopathogenic fungus of considerable agronomic importance, responsible for branch canker in almond (Prunus dulcis [Mill.] D.A. Webb) and peach (Prunus persica L.) trees. It represents a major phytosanitary threat to almond cultivation in Europe, particularly in Mediterranean regions. Almond is currently among the most rapidly expanding perennial crops, with cultivated areas increasing as a result of the introduction of new cultivars and the adoption of improved agronomic practices. The objectives of this study were to isolate and identify fungal pathogens from infected almond samples collected in France through multilocus phylogenetic analyses (ITS, tef1-α, his3, tub2, cal genes) combined with morphological characterization; evaluate the susceptibility of 18 almond genotypes, using ‘Ferragnès’ and ‘Texas’ as reference standards for susceptibility and tolerance, respectively; and compare three field inoculation methods. All isolates were identified as D. amygdali. The varietal screening identified marked differences in resistance among the tested cultivars. In particular, ‘Ferrastar’, ‘R1877’, ‘R1413’, and ‘R1542’ exhibited high levels of resistance, whereas ‘Tuono’, ‘Guara’, and ‘R1568’ showed susceptibility comparable to that of ‘Ferragnès’, which was used as the susceptible control. Among the inoculation methods evaluated, the mycelial plug technique proved to be the most consistent and reliable, outperforming both conidial suspension inoculation and the toothpick method coated with mycelium. These findings further confirm the genetic resistance of the cultivars ‘Ferrastar’ and ‘Ardèchoise’ to branch canker across different growing conditions, supporting their suitability for use in breeding and genetic improvement programs. Full article

Numerous ingredients in trichological shampoos are advertised as “active against hair loss”; however, the body of evidence behind such claims seems very limited or, in many cases, nonexistent. The aim of this study was to compile an inventory of substances advertised by shampoo manufacturers as “active” against hair loss and systematically review available evidence from clinical trials that would corroborate such claims. We screened declared compositions of trichological shampoos for ingredients advertised as active against hair loss or promoting hair growth. The second step was a systematic review of clinical trials of these substances used topically in the treatment of hair loss. A query in PubMed, Scopus, and Web of Science followed PRISMA and PICO guidelines with the strength of evidence assessed according to GRADE guidelines. We identified 43 trichological shampoos in which 112 individual ingredients were advertised as “active”. Of these, 36 ingredients were indicated as “active” in at least two shampoos and were subject to further study. In the search for evidence, 103,639 articles were screened for relevant information. Ultimately, we identified 29 clinical trials that tested 16 of the 36 ingredients for efficacy against hair loss. Only four ingredients were tested individually: adenosine (four trials; highest strength of evidence: moderate), caffeine (four trials; moderate), placental protein (two trials; low), and melatonin (one trial; moderate). Another 12 ingredients of interest were only tested as parts of complex preparations: Achillea millefolium extract, arginine, biotin, hydrolyzed wheat protein, hydrolyzed soy protein, Panax ginseng, panthenol, piroctone olamine, Prunus amygdalus dulcis, Rosmarinus officinalis, Serenoa serrulata, and Urtica dioica. Such a study design made it impossible to attribute the observed effects to any specific ingredient. No clinical trials of efficacy could be found for the remaining 20 (55.6%) substances repeatedly cited as “active”. At the present stage, scientific evidence for efficacy against hair loss is available only for caffeine, adenosine, placental proteins, and melatonin, but the overall strength of evidence is low. Moreover, a substantial majority of topical ingredients promoted as “active against hair loss” were never actually tested in clinical trials to verify such claims. While unsubstantiated claims of supposed beneficial properties often refer to alleged scientific evidence, there are major gaps to be filled in the field of non-prescription treatments for hair loss. Full article

In this study, fallen leaves of Azadirachta indica and Prunus dulcis were treated as waste materials for the production of energy-intensive bio-coal briquettes. The physical composition revealed that the moisture content ranged from 6.8% to 8.8%, fixed carbon from 10.7% to 14.0%, volatile matter from 71.2% to 77.1%, and ash content from 4.1% to 7.6%. The chemical structure of the biomass fuel, which included carbon, hydrogen, nitrogen, sulfur, and oxygen, was noted to be 44.56–50.69%, 7.12–7.33%, 0.14–0.25%, 0.47–0.79%, and 41.08–47.46%, respectively. The higher heating value ranged from 16.8 to 18.3 MJ/kg. With increasing pressure from 5 to 20 MPa, briquette density increased from 654 to 995 kg/m³, shatter index from 81% to 94%, durability from 67% to 92%, and resistance to water penetration from 57% to 77%. A low-pressure briquette (5 MPa) burned at a higher rate of 8.0 g/min, whereas a high-pressure briquette (20 MPa) burned at a lower rate of 2.5 g/min. All leaf types tested were able to boil 1000 mL of water with 100 g of briquettes in just 7 min. Full article

Microbial priming is an emerging strategy in sustainable agriculture that involves the use of beneficial microorganisms to enhance agricultural productivity and sustainability. This innovative approach leverages the natural interactions between plants and microorganisms to promote plant growth and improve soil health. This study explores the application of microbial priming on almond seeds, focusing on the biostimulant effect of soil-based microbial extracts from a mediterranean shrub Pistacia lentiscus L. as an ecological strategy to improve the germination and seedling of almond (Prunus dulcis (Mill.)). The extraction process of soil differentiates three extracts: the first separates AMF spores (Myco) from all other bacterial and fungal consortia (MW), and the third combines the two previous extracts (MW + Myco). The experiment evaluated germination rates, seedling growth parameters, and conducted physico-chemical soil analyses. Arbuscular Mycorrhizal Fungi (AMF) colonization was also measured. Microbial priming significantly improved germination rates and enhanced seedling growth compared to untreated controls. The three microbial extracts showed significant effects on germination rate after 20 days, exceeding 90%. After 27 days, all treatments reach their maximum (100%). Seedling indicators allow MW + Myco extract to be considered as the most powerful extract on almond seedling growth. The combination of microbial and endomycorrhizal fungal extracts could be considered as a facilitator of seedling growth of almond. The AMF colonization was notably higher in treated plants. Overall, microbial priming effectively enhances almond seed germination and seedling growth, demonstrating its potential as a sustainable biostimulation strategy in agriculture. This practice boosts crop productivity and promotes soil health by enriching microbial communities and improving nutrient cycling. These results open up perspectives towards a natural-based strategy able to facilitate the germination and early seedling of almonds in both nurseries and in the field—and to enhance the productivity and health of almond cultivation in special Mediterranean area. Full article

Almond hulls and shells, the byproducts of the almond industry, were analyzed to assess their potential valorization pathways. Shells showed a higher content in lignin and polysaccharides, but very low levels of extractives and inorganics. Hull’s high polar extractives fraction showed poor phenolic preponderance and antioxidant activity, but high sugar and mineral contents, and its lipophilic extracts were highly enriched in triterpenes (from 73.5% to 91.3%), while shells presented more fatty acids (27.4% to 34.2%) and sterols (17.4% to 29.1%). Shells exhibited much higher S/G ratio (syringyl to guaiacyl units) in their lignin polymer (1.0 to 1.4), compared to hulls (0.5 to 0.6). After mineral analyses, hulls showed high amounts of potassium (3.7–4.9%). Fixed carbon content was similar for both materials, but shells showed a higher energetic content, ~20 MJ/kg. Finally, both hulls and pellets increased the water holding capacity (WHC) of the soil by 50%, when added in weight percentages of 6.25% (hulls) and 25% (pellets). With these results, the range of possibilities for these waste materials is exciting: shells could be used to obtain hemicellulose oligosaccharides, while hulls could be used in sugar extraction for biotransformation or as a soil amendment. Full article

Through highly detailed data acquisition, a precision agriculture approach leads to the optimization of inputs, improving, for instance, water and nutrient use efficiency. High-resolution vigor mapping in perennial orchards provides the spatial detail required to achieve such targeted management. This exploratory case study characterizes the spatial variability of vegetative vigor in a young SHD almond orchard in southern Sardinia by integrating high-resolution unmanned aerial vehicle (UAV) imagery and Normalized Difference Vegetation Index (NDVI) mapping with two consecutive seasons of ground measurements; the NDVI raster was subsequently used to delineate three distinct vigor zones. The NDVI was selected as a reference index because of its well-assessed performance in field-variability studies. Field measurements, during the kernel-filling period, included physiological assessments (stem water potential (Ψ_stem), SPAD, photosynthetic rates), morphological evaluations, soil properties, yield, and quality analyses. High vigor zones exhibited better physiological conditions (Ψ_stem = −1.60 MPa in 2023, SPAD = 38.77 in 2022), and greater photosynthetic rates (15.31 μmol CO₂ m⁻² s⁻¹ in 2023), alongside more favorable soil conditions. Medium vigor zones showed intermediate characteristics, and balanced soil textures, producing a higher number of smaller almonds. Low vigor zones exhibited the poorest performance, including the most negative water status (Ψ_stem of −1.94 MPa in 2023), lower SPAD values (30.67 in 2023), and coarse-textured soils, leading to reduced yields. By combining UAV-based NDVI mapping with ground measurements, these results highlight the value of precision agriculture in intra-field variability identification, providing a basis for future studies that will test site-specific management strategies in SHD orchards. Full article

Almonds are one of the major products that are economically competent and compatible with the Mediterranean climate, a key characteristic that distinguishes Lebanon. The present study aims to examine the suitability of land use and land cover on the Lebanese territory for sustainable almond cultivation, based on the FAO land suitability criteria. The research explored the existing areas of almond cultivation and the land possessing the potential for almond cultivation in Lebanon using an analysis model developed on GIS. The evaluation of Land Suitability (LS) based on GIS and Multi-Criteria Evaluation methods (MCE) with Weighted Overlay (WO) was applied, and the almond suitability map was rendered using the seven following parameters: temperature, rainfall, slope, elevation, soil pH, soil texture, and soil depth. These variables were integrated through GIS and were allocated to different weights to each thematic layer, as per its relevance. Ultimately, the almond suitability map was established, comprising four categories: highly suitable, moderately suitable, marginally suitable, and not suitable. The obtained results indicated that almond cultivation areas were around 5500 ha in 2010, while more than 60% of the study area can be planted with almonds in accordance with the almond suitability map. In closing, the targeted decision-makers will potentially deem this study as a valid source of knowledge for planning land use, and a tool to mitigate land degradation. Full article

Organic farming systems, which prohibit synthetic fertilizers, often rely on legumes for their ability to fix atmospheric nitrogen (N). In orchards, legumes can be established as cover crops between tree rows to enhance nutrient cycling. This study evaluated the effects of two legume cover crops, white lupin (Lupinus albus L.) and hairy vetch (Vicia villosa Roth), compared to a Control treatment with conventional tillage, which is the most commonly used method of soil management in the region, in an organically managed almond [Prunus dulcis (Mill.) D.A.Webb] orchard compliant with European Union standards, in an experiment arranged as a completely randomized design. In the first year, kernel yield was highest in the Control treatment (404 kg ha⁻¹), while significantly lower yields were recorded for white lupin (246 kg ha⁻¹) and hairy vetch (283 kg ha⁻¹), likely due to competition for resources between cover crops and trees. In the second year, however, the trend reversed, with cover crop treatments yielding significantly more (Lupin: 313 kg ha⁻¹; Vetch: 296 kg ha⁻¹) than the Control (199 kg ha⁻¹). The cover crops accumulated over 150 kg ha⁻¹ of N in their tissues, enhancing soil N availability and increasing N concentrations in almond leaves. In addition to N, cover crops influenced the cycling of other nutrients, increasing potassium (K) and boron (B) concentrations while reducing calcium (Ca) and manganese (Mn) in plant tissues. Despite being derived from a two-year study, these results highlight the complexity of interpreting cover crop effects, underscoring the need for further long-term research to provide more comprehensive guidance to growers. Full article

Almond decline and dieback have become significant challenges in newly established orchards, with symptoms including internal necrosis, canker, and external gummosis. This work aims to explore the potential fungal and bacterial causative agents through metabarcoding and traditional culture plate isolation across six almond cultivars. Our results emphasize the multifactorial nature of almond decline and dieback, with possible co-infections by opportunistic fungi and bacteria playing a central role. Classical isolation identified 47 fungal species or genera, including Diaporthe amygdali, Diplodia corticola, Phytophthora sp., and several Fusarium species. Almond metabarcoding revealed a more diverse microbial community, highlighting the prevalence of soilborne pathogens such as Neocosmospora rubicola, Dactylonectria estremocensis, and Plectosphaerella niemeijerarum. Soil metabarcoding suggested that these pathogens likely originate from nursery substrates or soils shared with other crops, such as olives and vineyards, that serve as a source of inoculum. ‘Soleta’ generally presented lower richness when compared to the other tested cultivars, suggesting a higher degree of biotic stress and decreased plant resilience. This study highlights the value of integrating NGS approaches to comprehensively study complex diseases and the need for further research on pathogen interactions and cultivar susceptibility for the future development of new sustainable, targeted management strategies in almond orchards. Full article