Search Results (292)

Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CLas) and vectored by Asian citrus psyllid (Diaphorina citri), remains a major constraint to sustainable citrus production. In Florida, individual protective covers (IPCs) have been adopted as an effective psyllid exclusion tool by shielding young trees from this vector of the phloem-dwelling bacterium CLas. Brassinosteroids (BRs), a class of plant steroid hormones, are being explored as a treatment to mitigate HLB and are approved for commercial use in the state. We investigated the effect of IPCs combined with homobrassinolide (HBr) applied as a foliar spray on CLas titer, canopy volume, tree growth, yield, fruit quality, and defense-related gene expression of the salicylic acid (SA) pathways in ‘Tango’ mandarin grafted on sour orange (SO) or US-942 rootstocks. After being covered with IPCs in the field for three years, trees were subjected to monthly foliar application of HBr upon IPC removal. The experiment included four treatment groups: trees with IPC and HBr spray (IPC HBr+), IPC without HBr (IPC HBr-), no-IPC with HBr (no-IPC HBr+), and no-IPC without HBr (no-IPC HBr-). IPCs effectively delayed bacterial infection for six to nine months after IPC removal, maintaining higher cycle threshold (Ct) values (lower CLas titers) than in no-IPC trees, confirming the protective effect of IPCs against early CLas colonization. The combination of IPCs and HBr spray significantly enhanced canopy volume, particularly in trees grafted on SO. This effect was sustained over one year and was consistently greater in IPC HBr+ trees than in IPC HBr- and no-IPC HBr+ or HBr- trees, suggesting a synergistic effect of the combined therapy on enhancing tree growth. The tree height and trunk diameter were primarily improved by IPC, regardless of HBr treatment. IPC-treated trees exhibited significantly greater height and trunk diameters (scion and rootstock) than no-IPC trees across one or both rootstocks, indicating that IPCs alone contribute to these horticultural growth improvements. IPC trees also showed reduced preharvest fruit drop compared to the no-IPCs trees, resulting in higher yields, with additional gains observed in IPC HBr+ trees on SO. Fruit quality attributes, including °Brix, titratable acidity, peel color, and size, did not differ significantly among treatments. Importantly, gene expression analysis revealed early and sustained upregulation of key SA pathway genes in IPC HBr+ trees, indicating that HBr effectively activated systemic acquired resistance (SAR), particularly on SO rootstock. This study highlights the complementary roles of IPCs and HBr in the management of HLB. While IPCs provided essential early protection against CLas and promoted long-term horticultural growth, HBr enhanced early canopy development, activated host defense mechanisms, and enhanced yield. The integration of both approaches offers a sustainable and effective strategy to protect young citrus trees, delay CLas infection, and improve tree health and productivity under endemic HLB. Full article

The duration of the effective harvest period is of great interest among growers. Longer periods enable better workload and optimization of operations. Decisions are typically made based on fruit drop and firmness. Preharvest spray treatment of Harvista™ (1-methylcyclopropene; AgroFresh Inc., Philadelphia, PA, USA) was applied to ‘Gala’ and ‘Golden Delicious’ apples to delay maturation. Apples were harvested 7–21 days and 7–26 days after treatment for ‘Golden Delicious’ and ‘Gala’, respectively. Fruit drop, fruit diameter, ethylene production, firmness, soluble solids content (SSC), starch index and color were measured. Measurements were performed at harvest and after 7 days’ shelf life. Quality parameters suggest different extensions to the harvest period. The SSC models showed that a 5% increase can occur with longer than 6 days delay in harvest. The starch index models showed 9.6 days’ delay for ‘Gala’ and 6.3 days’ delay for ‘Golden Delicious’ apples. The accurate measurement of firmness and the performance of its models suggest that the harvest period can be extended by 12 days for ‘Gala’ and 11 days for ‘Golden Delicious’ apples, when fruit are subjected to preharvest spray treatment. Full article

The aim of this study was to optimize the pre-harvest application of seaweed-based biostimulants (BIOs) to improve potato yield, quality, and post-storage attributes. To achieve this, six potato cultivars differing in maturity periods were subjected to three BIO concentrations (2.4, 7.2, and 9.6 g/L), application timings (from planting to post-bloom), and frequencies (1–4 applications). The results indicated that BIO efficacy was strongly cultivar-specific. Responsive cultivars (such as ‘Minshu No. 1’, ‘Leshu No. 1’, ‘Xiazhai 65’, and ‘Qingshu No. 2’) showed significant yield increases when treated with 7.2 or 9.6 g/L BIO applied 3 to 4 times during key developmental stages (from seedling to 3 weeks after full bloom). In contrast, ‘Qingshu No. 10’ and ‘Qingshu No. 9’ exhibited no significant response. Post-storage analysis revealed that optimal BIO treatments in responsive cultivars (‘Minshu No. 1’ and ‘Xiazhai 65’) delayed the losses in dry matter content and starch content after 3 months of storage at 7.5 °C. Furthermore, BIO application significantly enhanced the uptake of potassium (K) in ‘Minshu No. 1’, ‘Xiazhai 65’, and ‘Qingshu No. 2’ potatoes. In conclusion, applying 7.2 g/L BIO three times during the seedling to post-bloom period is a potential strategy to enhance yield and quality for responsive early- and mid-maturing potato cultivars, offering a targeted solution for sustainable potato production. Full article

Postharvest quality deterioration of Korla fragrant pear (Pyrus sinkiangensis Yu) severely constrains its market value, yet the regulatory role of preharvest soil management in shaping postharvest performance remains poorly understood. Although green manure is widely adopted to ameliorate orchard soil degradation, species-specific modulation of postharvest storage trajectories and the quantitative fidelity of soil-to-fruit nutrient transmission have rarely been resolved for climacteric pear species. This study investigated how green manure species modulate fruit quality at harvest and during postharvest storage life and their underlying soil–fruit linkages. Three preharvest treatments were imposed, as follows: control (CK), sweet clover (CM), and alfalfa (MX). Fruits were harvested and stored at 4 °C, with samplings at 1, 5, 10, 15, and 20 d. A critical quality transition was identified at 15 d, characterized by the concurrent peaking of soluble sugars, organic acids, vitamin C, and anthocyanins alongside an optimal sugar–acid ratio. Beyond this inflection point, CM and MX diverged markedly: CM enhanced soluble sugar accumulation, anthocyanin retention, and ester volatile production—most notably hexyl acetate, which increased over 14.4-fold—thereby generating a pronounced fruity aroma bouquet. Conversely, MX sustained higher amino acid and vitamin C levels and conferred superior late-storage stability, evidenced by a three-fold lower coefficient of variation in the sugar–acid ratio relative to CK. Partial-least-squares structural equation modeling (PLS–SEM) revealed soil fertility as the principal exploratory associative factor of fruit quality, but the fidelity of soil-to-fruit transmission was species-dependent. MX exhibited the highest observed associative strength (R² = 0.971), whereas CM exhibited attenuated transmission fidelity (R² = 0.777), with network analysis further indicating that CM exhibited divergent associative patterns of key soil–fruit correlations. These findings suggest that green manure identity is linked to postharvest quality through divergent soil–fruit coupling pathways: alfalfa shows nutrient transmission efficiency and stabilizes nutritional quality, whereas sweet clover promotes sugar-aroma accumulation at the cost of reduced soil–fruit conversion fidelity. Species-specific green manure selection thus offers a viable strategy for targeted modulation of postharvest traits in Korla fragrant pear. Full article

Chestnut brown rot caused by Gnomoniopsis smithogilvyi represents an increasing threat to Castanea sativa production, although its endophytic behaviour and response to pre-harvest management strategies under field conditions remain poorly understood. This study evaluated the occurrence of G. smithogilvyi in different chestnut tissues and assessed the effects of targeted field treatments on pathogen colonisation and fruit quality in commercial orchards located in north-eastern Portugal. Field trials included applications of a biological fungicide (Problad^®), an inorganic micronutrient fertilizer (Fungicrops Bio^®), a sulfur-micronutrient fertilizer (KSC Mix^®), and a potassium-phosphonate chemical fungicide (Fosetyl-Al^®), alongside untreated control orchards. Samples of leaves, branches, burrs, and nuts were subjected to microbiological and molecular analyses, while fruit external quality parameters were also assessed. G. smithogilvyi was detected in all analysed organs, confirming its widespread endophytic occurrence. Treatment effects were more pronounced in reproductive tissues, with Problad^® and Fosetyl-Al^® significantly reducing pathogen incidence in burrs and nuts compared with the control. KSC Mix^® promoted fruit development but did not significantly reduce fungal incidence. Treated orchards generally showed improved fruit quality and lower insect infestation. Phylogenetic analysis confirmed the identity of all isolates as G. smithogilvyi. Overall, the results highlight the complexity of managing chestnut brown rot and support the need for integrated and sustainable disease management strategies. Full article

Betalains are natural antioxidant pigments valued as food colorants (E162), yet their combined responses to light quality and methyl jasmonate (MeJA) during long-term growth remain poorly understood. In this study, the interactive effects of blue light and MeJA on growth, betacyanin, betaxanthin, antioxidant enzyme activities [peroxidase (POD), superoxide dismutase (SOD), catalase (CAT)], malondialdehyde (MDA), and proline (PRO) were investigated at weeks 3, 10, and 13 of sugar beet seedling growth. Four treatments were established: white light (W, control), white light + MeJA (WM), white light + blue light (WB), and white light + blue light + MeJA (WBM). The results showed that WB rapidly induced betaxanthin accumulation and enhanced SOD and POD activities while reducing MDA at week 3. MeJA alone triggered an explosive increase in betacyanin (45.74 mg·g⁻¹ FW) at week 10, accompanied by elevated activities of POD, SOD, and CAT. The combined treatment (WBM) maintained the highest betacyanin (36.48 mg·g⁻¹ FW) and betaxanthin (8.97 mg·g⁻¹ FW) contents, the lowest MDA level (17.17 nmol·g⁻¹ FW), and a high proline level (528.39 μg·g⁻¹ FW) at week 13, providing sustained pigment maintenance at the late stage. The three antioxidant enzymes exhibited a temporal division of labor: high SOD activity at the early stage, while POD and CAT activities continuously increased during the middle and late stages. Notably, the correlation between proline and MDA shifted from positive at week 10 to negative at week 13, suggesting a temporal transition in the protective role of proline against membrane lipid peroxidation during late-stage development. In conclusion, blue light and MeJA enhance the antioxidant capacity of sugar beet seedlings through a temporally synergistic pattern of “priming by blue light, burst by MeJA, and maintenance by combined treatment,” offering a potential preharvest regulation strategy for the production of natural pigments and functional food ingredients. Full article

Pre-harvest foliar application of chitooligosaccharide (COS) was evaluated for its impact on the flavor quality of Cabernet Gernischt wines. COS was applied at the young berry (YB) and early veraison (EV) stages across the 2022 and 2023 vintages. Physicochemical parameters, phenolic compounds, color index, volatile composition, and sensory quality were systematically analyzed. In 2022, alcohol content and total acidity increased in both treatment groups, total phenols increased in the EV group but decreased in the YB group. In 2023, alcohol and acidity showed opposite trends between the two treatment groups, while phenolic compounds decreased. COS treatment increased wine lightness and yellow tone but reduced red tone and color saturation. In 2022 vintage, YB treatment increased total volatiles with 8.18% and terpenoids with 138.91%, while esters increasing by 34.72–53.60%. In 2023 vintage, total volatiles decreased by approximately 15%, with esters significantly decreasing by 26.60% (YB) and alcohols by 25.96% (EV), while fatty acids increased by 32.70% (EV). OPLS-DA identified key aroma compounds, including phenethyl acetate, ethyl caprate, heptyl acetate, and isoamyl acetate. Aroma wheel analysis showed that fruity and floral notes were enhanced in 2022 but reduced in 2023, with the EV stage consistently performing better. Overall, COS application at the early veraison stage represents a promising strategy for modulating wine flavor quality. Full article

The effects of pre-harvest application of Bacillus velezensis LYB73 on rhizosphere soil properties, microbial communities, fruit quality, and flavor-related traits in different peach cultivars are still not well understood. In this study, three peach cultivars, “Jinxia” (JX), “Wanhujing” (WHJ), and “Youpantao” (YPT), were subjected to B. velezensis LYB73 treatment or a sterile-water control under field conditions. Rhizosphere bacterial (16S rRNA) and fungal (ITS) communities were analyzed by high-throughput sequencing. Soil physicochemical properties, fruit nutritional and functional components, antioxidant capacity, and electronic sensory traits were also evaluated. The application of LYB73 was associated with lower rhizosphere soil pH (5.52–6.82) and changes in several soil nutrient-related parameters. Microbial community analyses indicated that LYB73 treatment was accompanied by shifts in the composition of rhizosphere bacterial and fungal communities. For example, the relative abundance of Pseudomonadota increased in the JX treatment group, while Ascomycota was enriched in the JX and YPT treatment groups. At the genus level, taxa such as Gemmatimonas, Saitozyma, and Cephalotrichum showed increased relative abundance in some treated groups. Compared with the control, LYB73-treated fruits generally showed higher levels of reducing sugars, titratable acids, amino acids, total phenols, total flavonoids, and antioxidant capacity. The magnitude of these responses varied among cultivars: JX showed larger increases in total phenols, total flavonoids, and DPPH scavenging activity, WHJ showed a greater increase in amino acids and ABTS scavenging activity, and YPT showed the largest increase in superoxide anion scavenging activity. Electronic sensory analysis further suggested that LYB73 treatment affected taste and aroma-related traits, although the responses differed among cultivars. Correlation analysis showed that several dominant microbial genera were significantly associated with soil properties, fruit quality indices, and sensory indicators. Overall, these results suggest that pre-harvest application of B. velezensis LYB73 may influence rhizosphere microecology and fruit quality in a cultivar-dependent manner, providing preliminary support for its potential use in peach production. Full article

As representatives of early-flowering herbaceous peony types, certain cultivars known as the ‘Coral’ series are highly prized in the global cut flowers market for their unique dynamic color transitions from orange-red (amber) to creamy yellow during the florescence and senescence periods. Despite their strong growth vigor and high commercial value, these cultivars face critical postharvest preservation challenges, most notably rapid petal abscission and short vase life. Previous studies have confirmed that postharvest quality deterioration of these peony cut flowers, including undesired color fading and accelerated senescence of petals, is closely associated with ethylene and ROS accumulation. To address these development impediments, systematic optimization of the entire industrial chain is essential. Proposed countermeasures include preharvest regulation of environmental conditions and cultivation practices to establish a foundation for quality formation, as well as postharvest strategies such as precise harvest timing, anti-ethylene treatments, and full cold-chain logistics. Meanwhile, simplifying the distribution system and optimizing terminal vase preservation techniques are also crucial to maintain postharvest quality. In the long term, promoting sustainable development of the global cut-flower industry will require breeding new germplasm with low ethylene sensitivity from a global perspective, continuously optimizing agronomic practices to overcome year-round supply constraints, and accelerating the application of intelligent technologies such as the Internet of Things (IoT) in full chain quality management. Full article

Broccoli (Brassica oleracea var. italica) is highly nutritious, rich in vitamin C, glucosinolates, and minerals. However, its high postharvest respiratory rate leads to rapid quality deterioration, particularly chlorophyll degradation and yellowing under ambient conditions. In China, the lack of timely pre-cooling facilities exacerbates postharvest losses. Therefore, developing safe, effective and low-cost preservation methods for broccoli during transportation is of great practical importance. In this study, RNA sequencing was employed to analyze the effects of preharvest 1-methylcyclopropene (1-MCP) and postharvest pre-cooling combined with cold treatments on gene expression in broccoli. Transcriptome analysis revealed that both treatments significantly upregulated or maintained key genes involved in chlorophyll biosynthesis (e.g., Glutamyl-tRNA reductase (GluTR), porphobilinogen deaminase (PBGD), magnesium chelatase (MgCh)) and downregulated chlorophyll degradation-related genes (e.g., Chlorophyllase (CLH), pheophytinase (PPH), pheophorbide a oxygenase (PaO)), resulting in enhanced chlorophyll retention. Furthermore, chlorophyllide a oxygenase (CAO) was upregulated, while chlorophyll b reductase (CBR) was downregulated, suggesting modulation of the chlorophyll cycle. These findings elucidate the molecular mechanisms by which 1-MCP and pre-cooling combined with cold regulate chlorophyll metabolism, providing new insights into the gene regulatory network underlying the postharvest quality maintenance in broccoli. Full article

In the Philippines’ agricultural setup, pre-harvest cacao (Theobroma cacao) fruits are wrapped with low-density polyethylene (LDPE) for moisture retention and damage protection. Responding to the growing concern for its waste volume and scarcity of treatment, this research explores the co-hydrothermal carbonization (co-HTC) of cacao shells (CS) and LDPE as a method to convert agricultural waste with plastic into hydrochar for potential energy applications. Thus, observations on the thermal, physicochemical, and morphological changes from feedstocks to hydrochar are carried out. Optimal conditions of 200 °C for 60 min resulted in hydrochar with 21.11 MJ/kg and appreciable thermal properties. SEM micrographs show that hydrochar had increased surface area, a good fuel characteristic, and surface flaking on oversized LDPE film, suggesting relative LDPE degradation. EDX analysis reveals C, K, Ca, and Zn metals that affect chemical pathways. FTIR analysis further supports chemical synergy by preservation of functional groups innate from both parent materials. Kinetic and thermal evolutions are also investigated to reveal the influence of pretreatment on the stability of cacao shell-dominated hydrochar and the effectivity of biomass integration to facilitate relatively easier cracking of LDPE. The findings support co-HTC as a viable technology to enhance the circular economy by valorizing LDPE and cacao shells while promoting energy recovery and solid fuel production. Full article

Chilli is a major horticultural crop in tropical and subtropical regions that contributes substantially to the global culinary and economic sectors. However, anthracnose remains one of the most destructive diseases, causing severe losses in both field and stored fruits. Current management strategies offer limited long-term effectiveness, highlighting the need for sustainable alternatives. This study developed nanoemulsions (NEs) from Garcinia atroviridis fruit extract and evaluated their biocontrol potential against Colletotrichum capsici alone and in combination with Trichoderma harzianum. Two formulations, NE4 and NE7, exhibited good thermostability without phase separation at 25 and 54 °C, with droplet sizes of 135.1 and 124.1 nm, respectively, and were non-phytotoxic to chilli seedlings. In vitro, the nanoemulsions significantly suppressed C. capsici mycelial growth (62%) compared to the crude extract. Under rain shelter conditions, NE integrated with T. harzianum (T7 and T8) was highly effective in delaying disease onset and reducing disease severity, achieving 90.07% and 88.37% relative disease reduction, respectively. These treatments also produced the highest marketable yields, comparable to the synthetic fungicide Dithane M-45^® (2 g L⁻¹). In contrast, the untreated control group exhibited an 83% yield loss. The results indicate that nanoemulsions of G. atroviridis fruit extract, particularly when combined with T. harzianum, offer a promising and sustainable biological control option for managing pre-harvest chilli anthracnose. Their incorporation into integrated pest management programmes may reduce dependence on chemical fungicides and support safer chilli production systems. Full article

Climate change-induced abiotic stress, particularly heat and drought during olive oil accumulation, significantly threatens the productivity and oil quality of olive trees (Olea europaea L.). This study investigated the efficacy of pre-harvest elicitation using the biostimulants harpin and chitosan (both as commercially available products) under summer conditions in Greece, in commercially productive rainfed groves of cv. ‘Megaritiki’. Multivariate analysis (PCA and factor analysis) revealed that pre-harvest application of these elicitors successfully balanced the trade-off between oil yield and quality. Both harpin and chitosan maintained hydrolytic (free acidity—0.25 and 0.29 g oleic acid 100 g⁻¹, respectively, compared to 0.56 g oleic acid 100 g⁻¹ in the control) and primary oxidative markers (peroxides—4.16 and 4.16 meq O₂ kg⁻¹, respectively, compared to 5.20 meq O₂ kg⁻¹ in the control) at exceptionally low levels compared to untreated trees. The treatments induced a distinctive metabolic shift regarding volatile compounds governed by the lipoxygenase (LOX) pathway. Harpin application was strongly associated with complex floral and fruity volatile compounds (2-hexen-1-ol and trans-2-hexenal) and a high α-tocopherol concentration (38.58 mg kg⁻¹ compared to 23.12 mg kg⁻¹ in the control), suggesting an enhanced physiological response in favor of oil quality attributes. Conversely, chitosan elevated the oxidative stability of the oil by increasing total phenol concentration (by almost 97% compared to the control) and prioritizing the accumulation of the stable monounsaturated fatty acids (oleic acid—increased by 12.5% compared to the control) over polyunsaturated ones (linoleic acid), while endowing the oil with desirable “green freshness” aromas (cis-3-hexenal). These results demonstrate that elicitation with harpin and chitosan is a potent tool for sustainably enhancing extra virgin olive oil quality under rainfed conditions in Greece, steering fruit metabolism toward a premium nutraceutical and sensory profile and enhancing the functional properties of the oil (phenol content, antioxidant capacity, monounsaturated fatty acids, α-tocopherol and squalene). Full article

Adverse environmental and postharvest conditions challenge the functional quality of lemons, an economically vital citrus crop. Melatonin (MEL) has emerged as an effective regulator of plant stress responses and secondary metabolism. This study evaluated the effects of pre- and postharvest MEL treatments, combined with cold storage, on the fruit quality of two lemon cultivars (‘Fino’ and ‘Verna’). The research focused specifically on endogenous MEL and flavanone dynamics. Three experimental conditions were assessed: (a) preharvest MEL application at 0.1 and 1 mM; (b) preharvest treatment followed by cold storage; and (c) combined pre- and postharvest MEL treatment followed by cold storage. Preharvest treatments increased endogenous MEL at harvest in a dose- and cultivar-dependent manner. Specifically, 1 mM being optimal for ‘Fino’, while 0.1 mM was more effective for ‘Verna’. During cold storage, ‘Fino’ fruit, characterized by low basal endogenous MEL levels, showed a marked increase in MEL accumulation, suggesting the stimulation of biosynthesis. In contrast, ‘Verna’ fruit, which had initially high endogenous MEL content, exhibited a pronounced decline, indicating MEL consumption to counteract oxidative stress. Flavanone content increased dose-dependently after preharvest treatment and was preserved during storage in ‘Fino’ but declined in ‘Verna’. These findings demonstrate that the fruit cultivar must be considered a critical factor in MEL-based strategies, as identical treatments may yield markedly different outcomes even within the same species. Full article

Fresh figs are characterised by high perishability, leading to a limited postharvest shelf life. Consequently, preharvest elicitor application strategies have been explored to enhance their quality and storability. During the 2022 and 2023 seasons, figs (cv. Calabacita) grown under high-density conditions were treated with oxalic acid (OA; 1 and 2 mM), melatonin (MEL; 0.1 and 0.5 mM), and γ-aminobutyric acid (GABA; 10 and 50 mM) through foliar sprays applied two or three times. Fruits were harvested at commercial maturity and analysed immediately after harvest. Physicochemical and bioactive parameters were determined. Analysis of variance was used to assess treatment effects, and t-tests were used to evaluate differences in the number of applications and between seasons. Significant seasonal effects were observed, whereas no cumulative effect from repeated applications was detected. OA at 2 mM increased fruit weight (37.9 g) and size (42.5 mm) and delayed ripening. MEL treatments enhanced sugar accumulation (100.1 g kg⁻¹ and 96 g kg⁻¹ of glucose and fructose, respectively), while GABA treatments were associated with a more advanced maturity stage. Notably, OA (2 mM), MEL (0.5 mM), and GABA (50 mM) significantly increased enzymatic antioxidant activity by an average of 24% and non-enzymatic antioxidant capacity by around 17% in general terms. These results indicate that preharvest elicitor application is a promising and eco-friendly approach to improve the nutritional value and overall quality of fresh figs. Full article