Horticulturae, Volume 12, Issue 1 (January 2026) – 126 articles

Apple cultivation faces soil acidification and pollution due to excessive fertilization, compounded by a scarcity of potassium (K) fertilizers. Polyhalite, a natural multi-nutrient mineral, offers a potential sustainable alternative. Therefore, a three-year field experiment was conducted, comprising a no-potassium control (CK), two conventional potassium fertilizers (sulfate of potash-based and muriate of potash-based), and six polyhalite compound fertilizer treatments (with different basal and topdressing strategies), to evaluate their effects on apple growth and soil fertility. Results showed that the single topdressing application of potassium chloride-type polyhalite compound fertilizer (T6) achieved the highest yield in the final year, which was 10.11–28.03% higher than the other potassium-applied treatments. It also achieved the highest fruit vitamin C and soluble solids content (9.53 mg 100 g⁻¹ and 13.27%, respectively). The T6 treatment demonstrated the best performance in terms of agronomic efficiency and partial factor productivity of potassium fertilizer, reducing fertilizer waste and loss. Furthermore, the T6 treatment effectively increased soil pH, available potassium, and exchangeable calcium levels, thereby improving soil fertility. Thus, polyhalite proves effective in replacing conventional K fertilizers, with the single topdressing of MOP-type polyhalite compound fertilizer (T6) offering the most comprehensive agronomic and environmental benefits. Full article

Horticultural reliance on non-renewable peat faces critical sustainability challenges. Low-temperature biochar (LTB) presents a promising alternative, offering higher biochar yields and lower energy inputs compared to conventional high-temperature biochar. However, LTB’s distinct physicochemical properties necessitate empirical validation of its efficacy as a peat substitute. This study investigated rice straw-derived LTB (pyrolyzed at 350 °C for 10 or 30 min) as a peat substitute at different ratios (10%, 20%, 40%), combined with three Hoagland nutrient solution concentrations (25%, 50%, 100%), on the growth, substrate properties, and fruit quality of dwarf tomato. The results show that a 10–20% LTB substitution improved substrate physical properties (reduced bulk density, increased porosity) and promoted plant growth (biomass, height). Conversely, a 40% LTB substitution inhibited growth, primarily attributed to osmotic stress caused by excessively high substrate electrical conductivity (EC). At the optimal 10–20% rates, tomato yield and fruit quality (soluble solids, lycopene, vitamin C) were significantly enhanced. Most importantly, a comprehensive evaluation revealed that 10–20% LTB substitution allowed for a 50% reduction in nutrient solution concentration while achieving a comprehensive performance comparable to the full-strength nutrient control. This study indicates that LTB could effectively replace a portion of peat, potentially enhancing dwarf tomato yield and quality while reducing chemical fertilizer dependency by up to 50%. These findings point toward a possible pathway for more resource-efficient horticultural practices. Full article

Hollowness of the cucumber fruit, caused by carpel separation during growth, severely impacts fruit quality. Several Sikkim cucumber accessions originating from the India–Pakistan region exhibit pronounced internal cavities. We previously identified the QTL mfh2.1 as a key contributor to this phenotype. In this study, we investigated the genetic and physiological basis of fruit hollowness in the Sikkim cucumber line WI7120 through an integrative analysis combining histological staining, HPLC for hormonal profiling, and fine mapping using a large F2 segregation population. Comparative analysis between the hollow-fruited WI7120 and the non-hollow line 9930 revealed distinct growth dynamics: WI7120 displayed accelerated radial expansion and aberrant cell patterning at carpel junctions. Histological examination using paraffin sectioning uncovered disorganized endocarp cell arrangements in WI7120 occurring as early as pre-anthesis (0 days post-pollination), with enlarged suture cells that likely facilitate tissue separation during fruit enlargement. Hormonal assays indicated elevated levels of gibberellin (GA) and zeatin (ZT), along with reduced indole-butyric acid (IBA) in WI7120, suggesting that a hormonal imbalance and mechanical stress contribute to compromised cell adhesion. By screening ~2000 F₂ individuals with SSR and InDel markers, we refined the mfh2.1 locus to a 50.92 kb interval on chromosome 2, pinpointing CsRPT4Bb—encoding a 26S proteasome subunit—as the candidate gene. A non-synonymous SNP (I135V) in CsRPT4Bb was associated with tissue-specific expression patterns during cavity formation, implicating proteasome-mediated cellular remodeling in carpel cohesion. Spatial-temporal expression analysis further revealed upregulation of CsRPT4Bb in the WI7120 exocarp during fruit expansion, potentially influencing cell wall dynamics. This study demonstrates a coordinated interplay among genetic, hormonal, and mechanical factors underlying cucumber fruit hollowness, offering new avenues for breeding cultivars with improved fruit integrity and postharvest quality. Full article

Bitter gourd (Momordica charantia L.) is widely consumed worldwide due to its unique flavor and medicinal value. In subtropical regions, low spring temperatures limit bitter gourd growth, leading to plant mortality and yield loss. Thus, elucidating the mechanisms of cold tolerance in bitter gourd could facilitate the development of cold-resistant cultivars via genetic engineering or molecular breeding. In this study, a cold-tolerant (CT) and a cold-sensitive (CS) inbred line of bitter gourd were used to investigate proteomic differences under cold stress. Before cold stress, 504 differentially accumulated proteins (DAPs) were identified, with 123 up-accumulated in CT plants compared to CS plants. Upon exposure to cold stress, these numbers changed to 388 DAPs (259 up-accumulated in CT) at 6 h and further to 649 DAPs (415 up-accumulated in CT) at 24 h. K-means cluster analysis identified 65 cold-stress response proteins that may contribute to cold tolerance in CT plants, including evm.TU.chr4.3733 (Proline dehydrogenase 1), evm.TU.chr10.115 (Delta(1)-pyrroline-2-carboxylate reductase), and evm.TU.chr10.815 (Calcium-dependent protein kinase 3). Glucose and starch levels remained stable in both CS and CT plants during cold stress, and the baseline concentration of glucose was consistently and significantly higher in CT plants than in CS plants. Before cold stress, proline content was similar in both CT and CS plants. Following 6 h of cold stress, CS plants accumulated significantly higher proline levels than CT plants. This trend, however, reversed after 24 h, with proline content becoming significantly lower in CS plants. Differential protein accumulation between CT and CS plants under cold stress reflects their distinct responses, with core DAPs serving as key functional determinants of enhanced cold tolerance in the CT genotype. This study revealed important proteomic data underlying the cold stress response in bitter gourd. Full article

Ascorbic acid (AsA) is a key antioxidant and nutrient in plants, regulating reactive oxygen species (ROS) levels and maintaining cellular redox homeostasis. The AsA recycling pathway sustains AsA pools by restoring its oxidized forms, ensuring intracellular balance. Among the enzymes involved, monodehydroascorbate reductase (MDHAR) is important for the regeneration of AsA from monodehydroascorbate. In this study, we analyzed the four MDHAR paralogs in Lactuca sativa using CRISPR/Cas9 to determine whether disruption of individual MDHAR genes could alter AsA levels in lettuce leaves. Unexpectedly, none of the knockouts caused long-term changes in leaf AsA content. Transcriptomic analyses at 14 and 28 days showed minimal effects on AsA recycling or biosynthesis genes, except MDHAR genes. However, several other genes indirectly implicated in AsA regulation displayed differential expression in all mutants compared to the wild type, suggesting the presence of a complex regulatory network. In particular, genes encoding transcription factors (TFs), such as mTERF15, COL9, UPBEAT1, NAC28, and NAC42, were differentially regulated in all MDHAR mutants compared to the wild type at 28 days. These findings indicate that, although AsA content remains unchanged, MDHAR single knockouts alter expression of other genes through which the plants may indirectly compensate to maintain redox homeostasis. Full article

This study considers citrus rootstocks as autonomous biological entities and examines whether, and to what extent, they differently regulate plant–water relations and biomass allocation as well as how such physiological variations translate into differences in vegetative vigor. To address these questions, four citrus genotypes—Sour Orange (SO), Volkamer Lemon (VL), Swingle Citrumelo (CTR), and Troyer Citrange (TC)—were compared with respect to their morphological traits, biomass distribution, and hydraulic properties. These four rootstocks were selected as they represent contrasting genetic backgrounds and well-documented differences in vigor, stress tolerance, and hydraulic behavior, providing an effective model for assessing intrinsic physiological variability. The findings reveal pronounced rootstock-specific differences in water acquisition, transport, and utilization, with direct implications for the hydraulic architecture, leaf water status, and partitioning of biomass between above- and belowground organs. CTR exhibited a highly integrated hydraulic strategy, characterized by elevated conductance across both aerial and root systems and accompanied by greater biomass allocation to the canopy and absorptive roots, resulting in an enhanced overall vigor. SO and VL displayed an intermediate physiological performance, whereas TC demonstrated a restricted hydraulic transport capacity, which is associated with lower biomass allocation, reduced leaf water potential, and diminished vigor. By assessing rootstocks independently of scion influences, this work demonstrates that variations between citrus rootstocks cannot be explained solely by morphological traits but instead reflect contrasting physiological strategies governing the coordinated management of water and carbon resources. These results highlight the rootstock as a central determinant of hydraulic functioning, biomass partitioning, and plant vigor and provide a conceptual basis for selecting rootstocks that are better suited to water-limited environments. Full article

The University Botanic gardens Ljubljana has been planting vegetation on bus stop shelters in the capital city (Ljubljana) of Slovenia since 2020. The aim of the project is to create a green network across the city, contributing to the conservation of plant biodiversity and providing food resources for pollinators throughout the entire growing season. The plantings were designed exclusively with native plant species, naturally occurring in the territory of Slovenia, flowering from early spring to late autumn. The selected species are also horticulturally attractive, forming small extensive green roof gardens that mimic karst rock ledges, where plants are adapted to drought, shallow soils, and strong sunlight exposure. In 2024 and 2025, monitoring was carried out on eight selected shelters, focusing on plant presence, changes in vegetation cover, and the occurrence of spontaneously sown species and invasive species. The results show that, even after five years without additional maintenance, all plantings are thriving and remain horticulturally attractive. A variety of species flower from early spring to early summer. During drought periods, flowering intensity decreases somewhat but does not cease; in autumn, the shelters green up again with autumn-flowering species. The project has been very well received by the public and is now firmly established in the city. Every year, between 10 and 20 new shelters are planted. By the end of 2025, a total of 75 bus shelters had been greened in all main directions from the city center towards the outskirts. Full article

Biochar, a highly effective amendment, is widely used for soil improvement and environmental remediation. However, research on its application in litchi (Litchi chinensis) cultivation is relatively scarce, particularly regarding its potential to enhance the rhizospheric soil ecological environment. In this study, a pot experiment was conducted to investigate the effects of biochar derived from maize (Zea mays) and rice (Oryza sativa), applied at different rates (3%, 6%, 10%), on the physical and chemical properties, enzyme activities, and microbial community structure and diversity in the rhizospheric soil of litchi seedlings. The results showed that biochar application significantly (p < 0.05) improved soil nutrient conditions, including total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), available potassium (AK), pH, and soil sucrase (SC) enzyme activity. Notably, treatment with 10% maize biochar exhibited the most pronounced improvement across all parameters, barring AP. Furthermore, biochar application stimulated the proliferation of specific bacterial taxa (Acidobacteriota, Bacteroidota, and Chloroflexota) and fungal phyla (Ascomycota and Mortierellomycota), increasing bacterial diversity while decreasing fungal diversity and richness. Correlation analysis further revealed the close relationships between soil microbial communities and fertility factors. This study provides substantial evidence regarding the efficacy and feasibility of biochar in improving the rhizospheric soil ecological environment of litchi. It offers a theoretical foundation for the scientific application of biochar in orchard soil management. Full article

Roses held profound cultural and economic significance in ancient Greece and Rome, yet comprehensive documentation of their species diversity, cultivation practices, and horticultural innovations remains fragmented across archaeological, iconographic, and textual sources. This multidisciplinary study synthesizes evidence from classical texts, archaeological remains including recently identified rose stem fragments from Oplontis, and iconographic materials—including frescoes, coins, and mosaics—to reconstruct the horticultural systems and cultural landscape of roses in classical antiquity. Analysis of literary sources, particularly Theophrastus’s fourth-century BCE taxonomic descriptions, reveals systematic cultivation of diverse rose varieties with flowers ranging from white to deep crimson, including yellow variants, characterized by morphologies from simple to double forms and valued for fragrance intensity and re-blooming capacity. Archaeological evidence from sites such as Paestum, Pompeii, and Oplontis, including pollen samples, preserved wood fragments with diagnostic prickle patterns, and fresco representations, documents commercial rose production and specialized cultivation techniques that demonstrate significantly greater morphological diversity than textual sources alone indicate. Field research and collection documentation establish the origins of Mediterranean rose cultivation, while iconographic analysis identifies roses in religious ceremonies, festivals, and daily life contexts. Textual sources provide detailed propagation methods, seasonal management practices, and evidence of Mediterranean hybridization events, alongside extensive documentation of medicinal and cosmetic applications. Economic analysis reveals specialized trade networks, commercial production centers, and diverse applications in perfumery, garland making, and pharmaceutical industries. This research establishes that Greek and Roman civilizations developed sophisticated rose cultivation systems integrating botanical selection, horticultural innovation, and cultural symbolism that directly influenced medieval and Renaissance practices and informed modern trait categorization systems. These findings demonstrate the foundational role of classical antiquity in European rose heritage, revealing how ancient horticultural knowledge, species diversification through hybridization, and cultivation techniques created an unbroken transmission that shaped contemporary rose industries and established conservation priorities for this horticultural heritage. Full article

Climate change introduces a critical threat to global viticulture, compromising grape yield, quality, and the long-term sustainability of Vitis vinifera cultivation. Addressing these challenges requires innovative strategies to enhance grapevine resilience. The integration of multi-omics data, predictive breeding, and physiological insights into ripening and stress responses is refining our understanding of grapevine adaptation mechanisms. In parallel, recent advances in plant biotechnology have accelerated progress from marker-assisted and genomic selection to targeted genome editing, with CRISPR/Cas systems and other New Genomic Techniques (NGTs) offering advanced precision tools for sustainable improvement. This review synthesizes the major achievements in grapevine genetic improvement over time, tracing the evolution of strategies from traditional breeding to modern genome editing technologies. Overall, we highlight how combining genetics, biotechnology, and physiology is reshaping grapevine breeding towards more sustainable viticulture. The convergence of these disciplines establishes a new integrated framework for developing resilient, climate-adapted grapevines that maintain yield and quality while preserving varietal identity in the face of environmental change. Full article

Cadmium (Cd) pollution is a global environmental issue that severely impacts crop growth and food safety. This study systematically investigates the accumulation characteristics and physiological responses of different varieties of non-heading Chinese cabbage under Cd stress. A Cd stress experiment was conducted using 79 non-heading Chinese cabbage varieties under nutrient film technique (NFT) cultivation, leading to the identification of 11 high-Cd accumulation varieties, 32 medium-Cd accumulation varieties, and 36 low-Cd accumulation varieties. The results showed that all varieties primarily accumulated Cd in the roots, with weak translocation of Cd to the aerial parts. To thoroughly analyze the physiological mechanisms of Cd accumulation, two extreme phenotypes, low accumulation (GX-61) and high accumulation (GX-05), were selected for subsequent comprehensive analysis. The low-accumulation variety (GX-61) exhibited higher sensitivity to Cd stress, with significant inhibition of leaf area, canopy area, and photosynthesis. In contrast, the high-accumulation variety (GX-05) maintained a more stable physiological state by enhancing photoprotective capacity and activating peroxidase (POD) to compensate for the functional loss of catalase (CAT). Cd stress inhibition of photosynthesis was initially limited by stomatal factors, later transitioning to non-stomatal limitations, and low concentrations of Cd induced a protective response that slightly promoted plant growth. This study, through high temporal resolution analysis at key growth stages, reveals the differential responses in growth, photosynthesis, and physiological metabolism between low- and high-Cd-accumulating non-heading Chinese cabbages, providing a theoretical basis for the selection of efficient phytoremediation materials and the safe production of non-heading Chinese cabbage. Full article

In the current climate change context and the potential to extend exotic crops in Romania, sweet potato could become an option for extensive areas with optimum ecophysiological conditions to provide economic and ecological benefits and assure food security. This study aimed to validate the suitability, photosynthetic performance, yield productivity, and sugar content of three sweet potato cultivars, KSC, Koretta, and Hayanmi, in Central Romania. Three key phenophases were selected: the beginning of flowering (P1), 50% tuber formation/full flowering (P2), and total tuber formation/leaves and stems bleached and dry (P3), respectively. At the beginning of flowering, extreme heat and moisture stress showed a reduced effect on the sweet potato development and photosynthetic parameters. The only exception was the assimilation rate for Hayanmi, which was markedly lower, with the highest relative chlorophyll content and leaf dry biomass. Koretta registered increased values for stomatal features. A higher tuber weight was registered for Hayanmi in P2 due to slightly increased rainfall and elevated evapotranspiration. In P3, the temperatures dropped sharply, rainfall exceeded evapotranspiration, and KSC accumulated a seven times higher value for tuber weight. The total biomass was 2–3 times higher for KSC in P3. Sugar content was negatively correlated with tuber weight, and Hayanmi had 1% higher values compared with KSC and Koretta. Sweet potato showed a variety-specific response to ecophysiological conditions, and for each variety, these physiological features suggest potential advantages for different cropping scenarios. Full article

The APETALA2/Ethylene Response Factor (AP2/ERF) family of transcription factors (TF) is characterized by their participation in various biological processes related to growth, development, and response to stress. ERFs are ideal candidates for crop improvement because they regulate defense genes like JERF1, JERF3, LeERF2, NtERF5, and Tsil which confer tolerance to drought, salinity, osmotic stress, and pathogen attack, respectively. The ERF subfamily includes the TF Pti4, whose activity is regulated by different signaling pathways, thus providing tolerance response to multiple factors such as drought, salinity, cold, and pathogen attack in tomato. In this work we evaluated the effect of overexpression of TF SlPti4 from Solanum lycopersicum in transgenic tobacco plants when subjected to saline, osmotic, and drought stress. Our results from this study demonstrated that transgenic lines overexpressing Pti4 tolerate abiotic stress during germination and in plants. The transgenic lines showed improvements in photoinhibition, electron transport rate, chlorophyll content, and biomass, as well as a reduction in malondialdehyde content. Full article

Black pepper (Piper nigrum L.) is an important crop in Pará, Brazil; however, irrigation management remains one of the main constraints to achieving stable productivity and high essential oil yield. By determining soil water tension for rational irrigation management that ensures high agronomic performance of black pepper, it is possible to optimize irrigation water use efficiency through monitoring critical soil moisture with the aid of tensiometers. This study evaluated yield, water use efficiency (WUE) and essential oil yield of two black pepper genotypes under five soil water tensions (15–55 kPa) using a split-plot experimental design. The Uthirankotta genotype showed higher yield and WUE, reaching maximum values at 35 kPa, whereas the highest essential oil extraction yield occurred at 15 kPa. Positive correlations were observed between essential oil yield and the main productive traits. Therefore, cultivation of the Uthirankotta genotype under tensiometer-based irrigation management is recommended under the edaphoclimatic conditions of Pará, using a critical tension of 35 kPa as a reference to increase productivity and optimize irrigation water use efficiency, considering the differential genotype response to irrigation management under humid tropical conditions. Full article

Grapevine downy mildew is a major disease in vineyards all around the world, caused by the oomycete Plasmopara viticola (Berk. & M. A. Curtis) Berl. & De Toni. Normally, its control depends almost exclusively on chemical and copper-based fungicides, especially in high-incidence areas with high relative humidity and mild temperatures. However, the European Union is determined to reduce the application of these phytochemicals by at least 50% by 2030, forcing winegrowers to seek alternative low-input strategies for proper sanitary maintenance. Basic substances (BSs), described in European Regulation (EC) 1107/2009, stand out as promising alternatives, but their molecular mechanism of action remains mostly unknown. In this context, this study analyzed the genetic effect in grapevine plants of several commercial products composed of BSs (chitosan, soy lecithin, Equisetum arvense and Salix cortex). All products exhibited promising results, triggering the induction of similar defence mechanisms, which included pathogenesis-related proteins (PRs), involved in direct pathogen repression; stilbenes, capable of producing antimicrobial compounds such as resveratrol and pterostilbene; several hormones, including oxylipins, ethylene, salicylic acid and terpenes, mediating immune signalling; and genes related to structural features of the plant, such as lignin, callose, cellulose and cuticular wax, constituting a first physiological barrier against P. viticola. Disease severity reduction differed among treatments, with Salix cortex showing the highest efficacy (58%), followed by BABA (38%) and LESOY (35%), while LECI and CHIT had minor effects (<9%). Gene expression analyses revealed that Salix cortex modulated the highest percentage of genes (41%), followed by natural infection without treatment (32%), LESOY (27%), BABA (26%), LECI (23%) and CHIT (23%). In terms of defence mechanisms, Salix cortex promoted the most pathways, LESOY induced eight, BABA and LECI seven and CHIT five. Overall, these results indicate that BSs can modulate several defence pathways in grapevine, supporting their potential use as sustainable alternatives for controlling downy mildew. Full article

In the last decade, avocado production has increased in Italy due to the fruit’s high nutritional quality and economic value. During 2024, stem lesions, wood discoloration and dieback, often starting at the grafting point, were observed in young plants in a nursery in Sicily (Italy). Colletotrichum-like colonies were frequently isolated from symptomatic tissues. Multi-locus phylogenetic analysis (gapdh, chs-1, act, tub2, cal, gs and ApMat) was conducted on 11 representative isolates, identifying 6 as C. perseae and 5 as C. gloeosporioides sensu stricto (s.s.). Two representative isolates were selected for pathogenicity tests performed on 2-year-old avocado plants cultivated in a greenhouse. After two months, necrotic lesions, wood discoloration and reddish-brown streaking at the inoculation point were induced in both species. Additional inoculations of avocado fruit confirmed the ability of both species to cause fruit rot. All inoculated fungi were successfully re-isolated and identified, fulfilling Koch’s postulates. This is the first report of stem lesions and dieback caused by Colletotrichum species and the first occurrence of C. perseae in avocado plants in Europe. The results highlight the importance of early monitoring in nurseries during the propagation process and contribute to a better understanding of fungal diseases in avocado crops in Italy. Full article

The introduction of Super-High-Density (SHD) olive orchards represents a crucial innovation in modern olive growing, enhancing sustainability. However, the long-term success of these planting systems depends strongly on cultivar selection, combining suitable vegetative and reproductive traits. This three-year field study investigated key floral biology parameters—flowering phenograms, gynosterility, and self-compatibility—of ten olive cultivars grown under irrigated conditions in southern Italy: ‘Arbequina’, ‘Arbosana’, ‘Cima di Bitonto’, ‘Coratina’, ‘Don Carlo’, ‘Frantoio’, ‘Favolosa’ (=‘Fs-17’), ‘I-77’, ‘Koroneiki’, and ‘Urano’ (=‘Tosca’). Flowering phenograms varied significantly across years and cultivars, showing temporal shifts related to chilling accumulation and yield of the previous year. Early blooming cultivars (‘Arbequina’, ‘Arbosana’, and ‘Coratina’) exhibited partial flowering overlap with mid-season ones, enhancing cross-pollination opportunities. Quantitative analysis of flowering overlap revealed that most cultivar combinations exceeded the 70% threshold required for effective pollination, although specific genotypes (‘Coratina’, ‘Fs-17’, and especially ‘I-77’) showed critical mismatches, while ‘Frantoio’ and ‘Arbequina’ emerged as the most reliable pollinizers. Gynosterility exhibited statistical differences among cultivars and canopy positions: ‘I-77’ showed the highest values (71.4%), while ‘Coratina’ and ‘Cima di Bitonto’ showed the lowest ones (7.3 and 8.4%, respectively). The median portions of the canopies generally displayed a greater number of sterile flowers (29.4%), reflecting the combined effect of genetic and environmental factors such as light exposure. In the inflorescence, the majority of gynosterile flowers were concentrated in the lower part, for all canopy portions (modal value). Self-compatibility tests were performed considering a fruit set of 1% as a threshold to discriminate. For open pollination, the fruit set was highly variable among cultivars, ranging from 0.5% in ‘I-77’ to 4.7% in ‘Arbosana’. Apart from ‘I77’, all varieties achieved a fruit set greater than 1%. Instead, for the self-pollination, only ‘Arbequina’, ‘Koroneiki’, ‘Frantoio’, and ‘Cima di Bitonto’ could be identified as pseudo-self-compatible, whereas ‘Coratina’, ‘Fs-17’, and the others were clearly self-incompatible and therefore unsuitable for monovarietal orchards in areas with limited availability of pollen. By integrating self-compatibility and gynosterility data, the cultivars were ranked according to reproductive aptitude, identifying ‘Cima di Bitonto’ and ‘Frantoio’ as the most fertile genotypes, whereas ‘Don Carlo’ and particularly ‘I-77’ showed severe genetic sterility constraints. The findings underline the critical role of floral biology in defining reproductive efficiency and varietal adaptability in SHD systems. This research provides valuable insights for optimizing cultivar selection, orchard design, and management practices, contributing to the development of sustainable, climate-resilient olive production models for Mediterranean environments. Full article

Delayed harvesting of grapes can alter fruit quality and plays an important role in alleviating the problem of market saturation during peak seasons, as well as in regulating the supply period of grapes. In this study, by conducting a comparative analysis of fruit quality, metabolomics (aroma compounds) and transcriptome sequencing of ‘Shine Muscat’ grapes harvested at six different on-tree ripening stages after maturity, we found that: (1) delayed harvesting led to dramatic variation in berry color change (light green to yellow) with a significant increase in soluble solids (19.5 to 20.89 Brix); (2) A total of 25 volatile aroma compounds was identified in collected berry samples, while trans-2-hexenal and hexanal exhibited the highest concentrations in all samples, marking them as key volatile compounds in ‘Shine Muscat’ grapes. Notable variation in the concentrations of linalool, n-butanol, benzyl alcohol, phenylethanol, β-citronellol, and propionic anhydride were recorded in selected harvest periods. OAV analysis results show that linalool has the largest OAV among the detected compounds, and its OAV proportion increased from 53% to 95% during the six sampling periods of ‘Shine Muscat’; (3) Transcriptome sequencing of selected samples demonstrated a positive correlation between eight terpene-synthesis-related genes and linalool accumulation. Furthermore, genes within the MEP pathway (specifically VvTPS55, VvTPS59) and several transcription factors were associated with terpenoids metabolism. Based on soluble solids and OAV results, T18–T22 period (18–22 weeks post-flowering) can become good quality on-vine storge berries. The gene expression profile and developmental patterns of metabolites in MEP pathway may helpful in functional characterization of candidate genes related to terpenoid metabolism in future studies. Full article

Traditional chemical analysis of plant tissue is time-consuming, costly, and poses risks due to exposure to toxic gases, highlighting the need for faster, low-cost, and safer alternatives. Vis-NIR spectroscopy, combined with machine learning, offers a promising method for estimating leaf nutrient levels without chemical reagents. This study evaluated the potential of Vis-NIR spectroscopy for nutrient estimation in leaf samples of banana (n = 363), mango (n = 239), and grapevine (n = 336) by applying spectral pre-processing techniques—smoothing (SMO) and first derivative Savitzky–Golay (SGD1d) alongside two machine learning methods: Partial Least Squares Regression (PLSR) and Random Forest (RF). Plant tissue samples were analyzed using sulfuric and nitroperchloric wet digestion and hyperspectral sensors. The prediction models were assessed using concordance correlation coefficient (CCC) and mean squared error (MSE). The highest accuracy (CCC > 0.80 and MSE < 2 g kg⁻¹) was achieved for Ca in banana, P in mango, and N and Ca in grapevine across both machine learning methods and pre-processing techniques. The predictive models calibrated for ‘Grapevine’ exhibited the highest accuracy—characterized by higher CCC values and lower MSE values—when compared with the models developed for ‘Mango’ and ‘Banana’. Models using SMO and SGD1d showed better performance than those using raw spectra (RAW). The high amplitudes and variations in nutrient levels, combined with large standard deviations, negatively affected the predictive performance of the models. Full article

Pathogenic bacteria utilize a type III secretion system (T3SS) to inject type III effectors (T3Es) into plant cells, suppressing plant immunity and facilitating colonization. Paracidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of Cucurbitaceae crops, harbors a functional T3SS like many other plant pathogens. The expression of its T3SS and T3Es is regulated by the two-component system response regulators HrpG and HrpX. Here, we demonstrate that the aspartic acid (Asp) residues at positions 52 and 60 in P. citrulli HrpG are essential for its complete function. Plasmid-mediated complementation of the ΔhrpG mutant with hrpG carrying Asp52→alanine (Ala) or Asp60→Ala mutations failed to restore the ability of P. citrulli to induce a hypersensitive response (HR) in tobacco, whereas the Asp46→Ala mutation fully rescued this phenotype. Furthermore, genomic hrpG point mutations generating strains Aac5 (D52A) and Aac5 (D60A) abolish the activation of hrpX transcription, resulting in decreased HrpX accumulation. Collectively, Asp 52 and Asp 60 in P. citrulli HrpG are essential for transcriptional activation activity of hrpX and HR induction, serving as a potential phosphorylation site (Asp 52) for upstream histidine kinases and a Mg²⁺ coordination site (Asp 60). Given that conserved Asp residues often function as phosphorylation sites in two-component system response regulators, this study provides a foundation for identifying upstream histidine kinases that modulate HrpG activity in P. citrulli. Full article

The granulation of pomelo (Citrus maxima) juice sacs severely compromises fruit quality and is closely associated with lignin accumulation, a process catalyzed by peroxidases (PODs). Analysis of ‘Sanhong’ pomelo juice sacs collected 175–215 days after flowering revealed that bound peroxidase (BPOD) activity paralleled changes in lignin content, suggesting a potential role for BPOD in lignin biosynthesis. A total of 71 CmPOD genes were identified in the pomelo genome through integrated HMMER and BLAST analyses. Among them, CmPOD52 was selected for functional characterization based on its alkaline peroxidase properties, absence of a CE domain, predicted extracellular localization, and gradually increasing expression pattern revealed by RT-qPCR. Its transient overexpression in ‘Sanhong’ pomelo juice sacs for 36 h increased BPOD activity 2.06-fold (p < 0.01) compared to the empty vector control, indicating that CmPOD52 may be a BPOD gene. The recombinant CmPOD52 protein was expressed in a prokaryotic system, purified, and used in enzymatic assays with sinapyl alcohol as the substrate. The recombinant CmPOD52 protein, assayed at 272 nm with controls (substrate-only blank and heat-inactivated protein), showed an activity of 13.67 ± 0.9 U. The experimental group showed new products, identified by mass spectrometry as sinapyl alcohol dimers, thus suggesting that the recombinant protein catalyzes the dehydrogenation and polymerization of sinapyl alcohol monomers. This study identified CmPOD52, a gene potentially involved in lignin polymerization in pomelo juice sacs, offering a key candidate for further in vivo validation. Full article

A two-factor experiment was conducted using the cultivar ‘Xin you No. 2’ (Citrullus lanatus) to identify an efficient and green production model for drip-irrigated watermelon under plastic mulch in Southern Xinjiang. A basal organic fertilizer was applied at 2250 kg·ha⁻¹. The experimental design comprised three irrigation levels, maintaining soil moisture at 60–70% (W1), 70–80% (W2), and 80–90% (W3) of field capacity, and three nitrogen application rates: 180 (N1), 240 (N2), and 300 (N3) kg·ha⁻¹. This study systematically investigated the effects of water–nitrogen coupling on watermelon yield, quality, water use efficiency, and nitrogen partial factor productivity. The W2N2 treatment achieved the highest yield of 64,617.59 kg·ha⁻¹. Vine length, stem diameter, and dry matter accumulation increased with increasing nitrogen application under the W1 and W2 irrigation levels, but exhibited an initial increase followed by a decrease under the W3 condition. Water restriction combined with increased nitrogen application significantly enhanced the central sugar content, with the W1N3 treatment increasing it by 15.69% compared to CK. Conversely, the W1N1 treatment was most conducive to vitamin C accumulation, showing a 49.88% increase over CK. The total water consumption across the different treatments ranged from 362.12 to 493.92 mm. Both water use efficiency and irrigation water use efficiency reached their maximum values under the W1N3 treatment, at 21.94 kg·m⁻³ and 35.05 kg·m⁻³, respectively. In contrast, the highest partial factor productivity of nitrogen (NPFP) was observed under W3N1, reaching 239.33 kg·kg⁻¹. A comprehensive multi-index evaluation using the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) method indicated that the W1N3 treatment achieved the highest relative closeness (0.669), identifying it as the optimal water–nitrogen combination. Full article

Pear black spot disease is a serious fungal disease during pear production; salicylic acid is a core signaling molecule that regulates the expression of plant disease resistance genes. To elucidate the intrinsic association between salicylic acid-induced resistance to pear black spot disease and lignin biosynthesis, in vitro plantlets of two pear cultivars, ‘Xinli No.7’ and ‘Xueqing’, were employed as experimental materials. After 60 h SA pretreatment, the leaves were inoculated with the pathogen Alternaria alternata. Leaf samples were harvested at 0, 8, 16, 24, and 48 h post-inoculation to determine phenylalanine ammonia-lyase activity, quantify lignin content, and analyze the transcript levels of genes involved in lignin synthesis. The results demonstrated that, relative to the untreated control group, SA treatment significantly enhanced phenylalanine ammonia-lyase activity and promoted lignin accumulation in both ‘Xinli No.7’ and ‘Xueqing’. Moreover, multiple key genes associated with lignin biosynthesis—including PbrPAL1, Pbr4CL1, PbrCOMT, PbrCCoAOMT, PbrCAD, and PbrPOD—were markedly upregulated, with their expression levels increasing by 3.5–15 fold. Transcript profiles of PbrHCT1, PbrHCT4, and PbrC3H1 exhibited cultivar-specific divergence between the two varieties. Notably, the susceptible cultivar ‘Xueqing’ displayed a distinct lag phase and attenuated response in the expression of all lignin-related genes compared with the other cultivar. This study provides reference for green prevention and sustainable development of pear. Full article

The adoption of green pest control technologies (GPCTs) has emerged as a critical factor in the pursuit of sustainable agricultural practices, particularly in improving farm efficiency and mitigating environmental impacts. This study investigates the effect of GPCT adoption on the technical efficiency of apple farmers in Shandong Province, China, using survey data collected in 2022. Applying advanced econometric techniques, including stochastic frontier analysis (SFA) to measure technical efficiency and endogenous switching regression model (ESR) to address endogeneity and selection bias, the findings indicate that GPCT adoption significantly enhances farmers’ technical efficiency. Specifically, under the counterfactual scenario of adoption, non-adopters’ technical efficiency would increase by 18.2% (from 0.669 to 0.851), whereas adopters would experience a 3.9% efficiency gain attributable to adoption (from the counterfactual 0.700 to the observed 0.739). The analysis further reveals that lower-income farmers benefit disproportionately from GPCT adoption, suggesting that the technology offers greater potential to enhance the productivity of resource-constrained farmers. These results underscore the importance of targeted policy interventions, such as subsidies and agricultural extension programs, to foster the widespread adoption of GPCTs, particularly among lower-income groups. This study contributes to the literature by providing empirical evidence of the dual benefits of GPCT adoption: improving farm efficiency while promoting environmental sustainability, with important implications for policy formulation in developing economies. Full article

WRKY transcription factors play critical roles in plant growth, development, metabolism, and stress responses. In this study, we performed the first genome-wide characterization of the WRKY gene family in Bupleurum chinense, using a T2T-level assembly of the autotetraploid genome. A total of 303 BcWRKY genes were identified and found to be unevenly distributed across four subgenomes. Phylogenetic and structural analyses revealed that segmental duplications after polyploidization drove lineage-specific expansion of the family. Meta-transcriptome analysis demonstrated that BcWRKY genes exhibited tissue-specific expression patterns and dynamic responses to stress, suggesting functional diversification. Under drought, waterlogging, methyl jasmonate, and ABA treatments, the contents of saikosaponins A and D significantly increased. This increase was accompanied by transcriptional activation of multiple BcWRKY genes. Correlation analysis between ten BcWRKYs and ten saikosaponins biosynthetic associated genes (BcBASs, BcCYPs, and BcUGTs) identified BcWRKY22, BcWRKY33, and BcWRKY46 as potential regulators of saikosaponin metabolism under stress conditions. Our study provided a comprehensive framework for understanding BcWRKY gene evolution and secondary metabolic regulation in polyploid medicinal plants. It also offered candidate genes for breeding B. chinense cultivars with high saikosaponin content. Full article

Drought stress represents a major constraint on global apple production, with the widely used semi-dwarfing rootstock ‘M.26’ being particularly vulnerable to water deficit. Although the osmolyte trimethylamine N-oxide (TMAO) has been shown to improve abiotic stress tolerance in the model plant Arabidopsis, its potential role in enhancing drought resilience in woody fruit trees remains largely unexplored. Under prolonged moderate drought stress, exogenous TMAO application significantly promoted plant growth, mitigating the drought-induced suppression of plant height by 5.3–12.2% compared to untreated drought-stressed controls and alleviating the decline in above-ground biomass. This improvement was underpinned by a substantial alleviation of root growth inhibition, with TMAO restoring total root length and biomass from 37% in the control to only 6.1–9.5%. TMAO also fine-tuned the root-to-shoot ratio to favor resource allocation to roots. Consequently, TMAO-treated plants maintained superior leaf water status, exhibiting higher relative water content (drought-induced reduction limited to ~17.5% with TMAO versus 26.3% in the control). Physiologically, TMAO alleviated the drought-induced stomatal limitation of photosynthesis, sustaining higher net photosynthetic rate, stomatal conductance, and transpiration rate. Crucially, under severe drought stress, TMAO pretreatment markedly enhanced ‘M.26’ survival rates from approximately 39% in the untreated control to 60–68%, representing a relative increase of approximately 74%. Collectively, this study demonstrates that exogenous application TMAO significantly enhances drought tolerance in apple rootstock ‘M.26’, highlighting its potential as an effective and environmentally safe plant growth regulator for more sustainable cultivation of fruit trees under irregular/erratic irrigation conditions. Full article

In the current context of climate change, special attention should be paid to assuring the security of food and fruits. Lemon trees struggle to keep their physiological traits stable in the context of all the cumulated challenges originating from climate stress. Therefore, our aim was to assess two seed priming methods’ long-term effects on some physiological parameters of young lemon trees. The relative chlorophyll content reveals that hydropriming shows 26% increases from E1 to E6, similar to the control, while osmopriming has a 31% higher value at the beginning and after three years. Leaf stomatal density has 80% lower values due to osmopriming compared to the control, while hydropriming show 15% lower values. Leaf area development was slightly similar between treatments, with more leaves being developed after hydropriming treatments. Guard cell width has similar values for priming, with both being with 40% higher than that of the control. Lemon trees grown after osmotic stress have the highest mass percentages of magnesium and potassium in the leaves. Hydropriming promotes calcium oxalate accumulation and a high mass percentage of phosphorus. The percentage allocation of carbon as dry matter is 32% for osmopriming, significantly higher than for the other treatments. The quantum yield of photosynthetic electron transport is the only significant photosynthetic parameter for osmoprimed lemon young trees. Physiological techniques successfully enhanced the overall growth of three-year-old lemon trees, especially osmopriming treatment. Full article

This study evaluated the extraction efficiency of two Natural Deep Eutectic Solvents (NADESs), glycerol–urea (1:1) and citric acid–sorbitol (1:2), for recovering phenolic compounds from the different parts of the fruit (pulp, seed-containing pulp, seeds, and peel) of Opuntia robusta and Opuntia ficus-indica in comparison with 50% methanol. Phytochemical profiling was performed using ultra-high-performance liquid chromatography–high-resolution mass spectrometry, alongside antioxidant and enzyme inhibition assessments (acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-glucosidase, and α-amylase). Glycerol–urea performed similarly to methanol in extracting phenolic compounds with notable antioxidant properties. Peel extracts contained the highest levels of bioactive compounds, particularly phenolic acids (525.49 in O. robusta and 362.96 µg/g_DW in O. ficus indica). Enzyme inhibition varied across species and fruit parts, with extracts from both species inhibiting all targeted enzymes. Notably, this study provides the first evidence of tyrosinase inhibitory activity in O. robusta, which exhibited the strongest inhibition. Overall, these results emphasize the potential of cactus fruit extracts, particularly from O. robusta, for valorization, and support the use of NADESs as a sustainable and medium for extracting antioxidant compounds. Furthermore, the potential of fruit peel as waste with nutraceutical applications was demonstrated. Full article

A key challenge in automated marigold harvesting lies in the accurate identification of picking points under complex environmental conditions, such as dense shading and intense illumination. To tackle this problem, this research proposes a lightweight instance segmentation model combined with a harvest position estimation method. Based on the YOLOv11n-seg segmentation framework, we develop a lightweight PDS-YOLO model through two key improvements: (1) structural pruning of the base model to reduce its parameter count, (2) incorporation of a Channel-wise Distillation (CWD)-based feature distillation method to compensate for the accuracy loss caused by pruning. The resulting lightweight segmentation model achieves a size of only 1.3 MB (22.8% of the base model) and a computational cost of 5 GFLOPs (49.02% of the base model). At the same time, it maintains high segmentation performance, with a precision of 93.6% and a mean average precision (mAP) of 96.7% for marigold segmentation. Furthermore, the proposed model demonstrates enhanced robustness under challenging scenarios including strong lighting, cloudy weather, and occlusion, improving the recall rate by 1.1% over the base model. Based on the segmentation results, a method for estimating marigold harvest positions using 3D point clouds is proposed. Fitting and deflection angle experiments confirm that the fitting errors are constrained within 3–12 mm, which lies within an acceptable range for automated harvesting. These results validate the capability of the proposed approach to accurately locate marigold harvest positions under top-down viewing conditions. The lightweight segmentation network and harvest position estimation method presented in this work offer effective technical support for selective harvesting of marigolds. Full article

Growing pressure on water resources and mineral fertilizer use calls for innovative and resource-efficient agri-food systems. Aquaponics, integrating aquaculture and hydroponics, represents a promising approach for sustainable greenhouse production. This study, aiming to explore alternative water and nutrient sources for greenhouse tomato production without compromising plant adaptability or yield, evaluated the co-cultivation of grape tomato and rainbow trout in a vertical decoupled aquaponic system under controlled greenhouse conditions. Two aquaponic nutrient strategies were tested: unmodified aquaponic water (AP) and complemented aquaponic water (CAP), with conventional hydroponics (HP) as a control, in a Deep Water Culture hydroponic system. Plant performance was assessed through marketable yield and physiological parameters, while system performance was evaluated using combined-biomass Energy Use Efficiency (EUE), Freshwater Use Efficiency (fWUE) and Nitrogen Use Efficiency (NUE), accounting for both plant and fish production. CAP significantly improved tomato yield (9.86 kg m⁻²) compared to AP (2.40 kg m⁻²), although it remained lower than HP (12.14 kg m⁻²). Fresh WUE was comparable between CAP and HP (9.22 vs. 9.24 g L⁻¹), demonstrating effective water reuse. In contrast, EUE and NUE were lower in CAP, reflecting the additional energy demand of the recirculating aquaculture system and nutrient limitations of fish wastewater. These results highlight aquaponics as a water-efficient production system while emphasizing that optimized nutrient management and energy strategies are critical for improving its overall sustainability and performance. Full article