Maintenance Of Fruit Quality Research Articles

Aroma volatiles and sensory quality of organically-grown apple cultivars after dynamic controlled atmosphere (DCA) storage and comparison with CA-stored fruit with and without 1-methylcyclopropene (1-MCP)

Long-term storage of many apple cultivars can be especially challenging for organic production where use of 1-methylcyclopropene (1-MCP), a crop protectant that controls ripening is disallowed. For many cultivars, controlled atmosphere (CA) storage alone, is inadequate for managing disorders and ripening. Dynamic controlled atmosphere (DCA), by determining the pO2 just above the lower oxygen limit (LOL), permits the use of lower pO2 setpoints without any negative impacts of anaerobiosis. Consequently, DCA can replace 1-MCP for maintenance of fruit quality. The goal of this study was to determine where this held true for a selection of old and new release organically-grown cultivars in the context of sensory perception. Cultivars included ‘Enterprise’ and ‘GoldRush’ harvested in 2018 (year 1), and ‘Honeycrisp’, ‘Golden Delicious’, ‘Jonagold’, and ‘Fuji’ harvested in 2020 (year 2). The LOL was monitored for DCA using chlorophyll fluorescence (CF) and compared with conventional static CA with or without 1-MCP treatment at harvest. DCA storage suppressed ripening to a similar level as 1-MCP plus CA in both years as indicated by reduced ester biosynthesis and, for some cultivars, maintenance of flesh firmness. However, ripening suppression did not impact the overall sensory preference of ‘Enterprise’, ‘Honeycrisp’, or ‘Fuji’, as all cultivars retained firmness and tartness regardless of storage regime and even negatively impacted it for ‘Goldrush’, an especially tart and firm cultivar. Sensory liking of ‘Golden Delicious’ and ‘Jonagold’ which have more typical diminishing firmness and acid profiles were most benefited by either 1-MCP treatment or DCA storage. The results highlight that use of storage technologies that suppress ripening beyond conventional CA storage are best employed on cultivars with more conventional softening and acid metabolism profiles as opposed to new cultivars that were selected primarily against these ripening phenotypes. The results also demonstrate the value of sensory evaluation compared with instrumental measurements to reveal the influence of different storage regimes on human perception.

Nano-TiO2 enhanced fruit storage chambers: unveiling the potential for prolonging banana shelf life

ABSTRACT This manuscript focuses on the development of Fruit Storage Chamber (FSC) equipped with nano-TiO2 and its modular prototype to improve the value of bamboo-based FSC by its photocatalytic and feasibility aspects. Its effects on fruit shelf life and ripening-related gene expression were studied. Cavendish bananas were stored in FSC equipped with nano-TiO2 and modular FSC for treatments. Relative expression level of ethylene biosynthesis-related (MaACS1, MaACO1) and polyphenol oxidase (MaPPO4, MaPPO5) genes were examined. The dynamics of ripening variables throughout the storage period were illustrated in regression lines, followed with hypothesis testing. Banana quantity showed no significant changes upon storage in FSC equipped with nano-TiO2. Physical appearance indicated a ripening delay of up to two days on nano-TiO2 treatments compared to control. Ethylene production rate and ethylene related gene expression were not significantly altered. Browning index was more maintained in nano-TiO2 treated samples, supported by the observation of slower increase of MaPPO4 and MaPPO5 relative expressions compared to control. The findings highlight the suppression of fruit ripening related gene expression and the maintenance of fruit quality in treated samples compared to control, indicating the potential use of nano-TiO2 to prolong banana shelf life.

Integration of single-cell and spatial RNA sequencing uncovers spatiotemporal transition of fruit senescence trajectory from exocarp to mesocarp in Pitaya (Hylocereus undatus)

Senescence is the last critical stage of the fruit life cycle, which directly affects the maintenance of fruit quality and post harvest lifespan. The pericarp consists of various cell types, making it challenging to elucidate their roles in fruit senescence. In this study, an expression atlas of H. undatus pericarp was constructed using scRNA-seq profiles, encompassing data from thousands of individual cells. Five different algorithms, including deconvolution (SingleR and SciBet), supervised learning (RCTD and CARD), and multi-modal cross-analysis (MIA), were employed to assign 17 transcriptionally distinct cell clusters identified in single cells to four different cell types: exocarp, mesocarp, endocarp, and vascular bundles. Pseudotime trajectory analysis revealed a clear spatiotemporal transition from ROS-induced stress and disease resistance to senescence during the fruit ripening process, moving from the exocarp to the mesocarp. Previously unknown early response genes related to senescence and resistance were identified, providing novel tools for fruit senescence prediction based on mesocarp and enhancement of fruit resistance based on exocarp.

Antioxidant Systems and Quality in Sweet Cherries Are Improved by Preharvest GABA Treatments Leading to Delay Postharvest Senescence.

γ-Aminobutyric acid (GABA) plays important roles in plant development, including the maintenance of fruit quality when applied as postharvest treatment. However, little information is available about the effects of preharvest GABA treatments. Thus, GABA (10, 50 and 100 mM) was applied as foliar spray at key points of fruit development in three sweet cherry cultivars and over two years. The results show that quality parameters, such as total soluble solid content, titratable acidity and firmness were higher in the fruit from GABA-treated trees than in the controls, either at harvest or during four weeks of cold storage. In addition, the total phenolic and total and individual anthocyanin concentrations were also enhanced by GABA treatments and the fruit color was improved. The activities of the antioxidant enzymes catalase, ascorbate peroxidase and peroxidase were also enhanced by the GABA treatments. The most effective concentration was 50 mM, which led to extending the storage period of sweet cherries with high quality traits to up to four weeks, while for the controls this was two weeks. Thus, GABA treatment had a clear effect on delaying the postharvest ripening and senescence processes in sweet cherries, with an additional effect on enhancing the content of bioactive compounds, such as phenolics and anthocyanins, with antioxidant properties and health benefits.

Antifungal edible coatings for fruits based on zein and chitosan nanowhiskers.

Fresh produce have a more limited shelf life than processed ones. Their sensory attributes such as appearance and surface texture are important features in consumer perception and liking. The decomposition of fresh produce, which is caused by enzymes, chemical reactions, and microbial infections, often caused by Colletotrichum species, is inevitable. However, it can be slowed down. Several materials have been developed for this purpose, with an emphasis on active coatings using nanomaterials. In this study, the protective effects of a zein coating containing chitosan nanowhiskers (CSW) for the maintenance of fruit quality were investigated using guava (Psidium guajava L.) as a model fruit. CSW were previously characterized, and their antifungal effects against distinct Colletotrichum species (Colletotrichum asianum, Colletotrichum tropicale, Colletotrichum gloeosporioides, and Colletotrichum brevisporum) were proven. Coatings were characterized by thermogravimetric analysis, optical profilometry, and mechanical properties. Total soluble solids, pH, mass loss, and visual inspection of uncoated and coated guava fruits were also verified during 9 days. Results show that CSW length and aspect ratio decreased for longer extraction times. A similar behavior was found for x-ray diffraction in which peak intensity decreases under the same conditions. CSW degradation (ca. 250-400°C) also depends on extraction time in which more crystalline whiskers are the most thermally stable ones. The addition of CSW did not significantly (p<0.05) modify the homogeneity and continuity of coating but prevented microbial growth assuring fruit quality during storage. In summary, coatings protected guava fruits from post-harvest spoilage while preserving quality and extending shelf life. PRACTICAL APPLICATION: Fresh foods such as fruits and vegetables have a more limited shelf life than processed ones.

Harnessing the metabolic modulatory and antioxidant power of 1-(3-Phenyl-Propyl) cyclopropane and melatonin in maintaining mango fruit quality and prolongation storage life

BackgroundThe aim of this study was to compare and investigate the effects of 1-(3-phenyl-propyl) cyclopropene (PPCP) and melatonin (MT) as anti-ethylene agents on postharvest senescence, quality, chilling tolerance, and antioxidant metabolism in the mango fruit cv. “Keitt”. The study involved exposing the fruit to 20 μL L− 1 PPCP or 200 μM MT, in addition to a control group of untreated fruit, before storing them at 5 ± 1 °C for 28 d. The findings revealed that the treatments with PPCP and MT were effective in reducing chilling injury and preserving fruit quality when compared to the control group.ResultsThe use of 20 μL L− 1 PPCP was an effective treatment in terms of mitigating chilling injury and preserving fruit quality for 28 d. This was attributed to the decrease in metabolic activity, specifically the respiration rate and the production of ethylene, which led to the maintenance of fruit firmness and bioactive compounds, energy metabolism, and antioxidant activity, such as ascorbic acid, total flavonoids, trolox equivalent antioxidant capacity, dehydroascorbate reductase, glutathione reductase activity, ATP, and ATPase activity. The study also found that the MT treatment at 200 μM was effective in reducing chilling injury and weight loss and improving membrane stability. Additionally, it led to a decrease in malondialdehyde content and electrolyte leakage, and the maintenance of fruit quality in terms of firmness, peel and pulp colour values for mango peel and pulp total carotenoid content, as well as phenylalanine ammonia lyase and tyrosine ammonia lyase activity. These findings indicate that PPCP and MT have the potential to be efficient treatments in maintaining mango quality and minimizing post-harvest losses.ConclusionThe utilisation of treatments with 20 μL L− 1 of PPCP or 200 μM MT was found to effectively preserve the postharvest quality parameters, in terms of bioactive compounds, energy metabolism, and antioxidant activity, of mangoes cv. “Keitt” that were stored at 5 ± 1 °C for 28 d.

PpeERF115 regulates peach fruit ripening by increasing polyamine turnover through up-regulation of genes involved in polyamine synthesis and catabolism

Polyamines (PAs) are anti-senescence agents that promote maintenance of fruit quality after harvesting. Many studies have reported increases in PA synthesis and catabolism and decreases in PA levels during fruit ripening. However, few reports have addressed the modulation mechanisms of PA metabolism during fruit maturation. In this report, we found that the peach (Prunus persica L.) transcription factor PpeERF115 directly bound to the PpeADC1 and PpePAO1 promoters, activating these genes. Silencing PpeERF115 enhanced spermidine (Spd) and spermine (Spm) accumulation, reduced putrescine (Put) content, decreased ethylene production, suppressed the respiratory rate, promoted maintenance of fruit firmness, and delayed peach ripening. Conversely, fruit over-expressing PpeERF115 showed significantly reduced Spd and Spm accumulation and clear increases in Put levels. RNA-sequencing analysis indicated that PpeADC1, PpeCuAO2, and PpePAO1 were dramatically down-regulated in PpeERF115-known out fruit, whereas PpeSAMDC1 was significantly up-regulated. This study is the first to show that PpeERF115 regulates peach ripening by increasing PA turnover through up-regulation of PA synthesis and catabolism. These results extend our comprehension of the coordination between ethylene and PAs during regulation of fruit maturation.

Post-harvest conservation of 'Shelly' and 'Omer' mangoes under refrigerated conditions cultivated in the sub-middle of the São Francisco Valley

Mango is one of the most important fruits in the world, but its high perishability after harvest limits its commercialization over long distances. Brazil stands out in world production and exports, showing an increasing potential for growth, either with the search for new cultivars or with the advance in the maintenance of fruit quality. Thus, the objective of this research was to evaluate the post-harvest conservation of Israeli mangoes 'Shelly' and 'Omer' stored under refrigerated conditions. The experiment was conducted at the Agricultural Product Storage Laboratory (LAPA), at the Federal University of São Francisco Valley (UNIVASF). The samples received were sanitized, stored for forty days at a temperature of 12 ºC and evaluated at five-day intervals for differences in absorbance (DA index), skin and pulp color (L*, a* and b*), mass loss (ML), dry matter (DM), firmness and soluble solids (SS). The experimental design was completely randomized in a 2 x 9 factorial scheme (cultivars x storage times), with four replications per treatment, except for DM and ML evaluations. Based on the results, the cultivar Omer responded better to the refrigeration condition for post-harvest conservation than Shelly, showing better performance in the evaluation of parameters of firmness, mass loss, dry matter and colorimetry. 'Shelly' performed better in terms of DA index and soluble solids.

Sulfur dioxide maintains storage quality of table grape (Vitis vinifera cv ‘Kyoho’) by altering cuticular wax composition after simulated transportation

The cuticular wax layer as a natural defensive barrier plays a key role in postharvest fruit quality maintenance. This study investigated the effects of simulated transport vibration (STV) on the berry quality and cuticular wax, and the ability of sulfur dioxide (SO2) to ameliorate STV damage in table grapes during cold storage. Results showed that STV damage accelerated the deterioration in grapes quality, and resulted in degradation and melting of cuticular wax, accompanied by a decrease in load of total wax, triterpenoids, fatty acids, alcohols, and olefins while an increase in alkanes and esters content during subsequent storage. However, SO2 effectively reversed the adverse impact of STV damage by increasing most wax fraction levels and corresponding genes expression, especially triterpenoids, although it had no apparent effect on wax structure. Overall, SO2 delayed the quality deterioration caused by vibration damage that occurs during transportation and storage by altering cuticular wax composition.

Transcriptome analysis reveals mechanisms of acetylsalicylic acid-mediated fruit quality maintenance in fresh-cut kiwifruit

Postharvest ripening and processing of fresh-cut (FC) kiwifruit brings quality deterioration and spoilage, including substantial changes in fruit color, texture and flavor. Hence, a series of preservation techniques have emerged to reduce postharvest loss and maintain FC kiwifruit quality. In this study, we evaluated the efficacy of acetylsalicylic acid (ASA), a derivative of plant endogenous hormone salicylic acid, in preserving the quality and delaying the ripening process of FC kiwifruit. Compared to the control fruit, ASA treatment maintained a better fruit appearance and higher fruit firmness, as well as reducing mass loss, total soluble solids and ethylene production. Based on the RNA-seq data and weighted gene co-expression network analysis (WGCNA), eight biosynthetic genes were identified as involved in fruit quality change, which participates in cell wall metabolism, starch degradation/sugar accumulation and ethylene biosynthesis. Moreover, the analysis showed that four transcription factors were significantly induced by exogenous ASA treatment. Dual-luciferase assays proved that ASA-responsive transcription factors regulated fruit quality-related genes, resulting in delaying ripening process and extending the shelf-life of FC kiwifruit. This study showed that ASA effectively delayed the ripening process, and AcWRKY7/AcDOF21/AcC2H2–151/AcbHLH123 are associated with the ASA-mediated fruit quality maintenance.

Survey Paper on Fruit Recognition, Classification and Quality Health Maintenance

This research focuses on fruit and vegetables classification, recognition based on its health and quality by using Raspberry pi board, which is further integrated with digital image processing techniques and machine learning concepts. Convolutional Neural Networks (CNN) is generally used to perform image identification and categorization in the object recognition systems. The recent advancements in deep learning-based models assist in performing complex image recognition. This study also proposes an effective CNN-based method for performing fruit recognition, fruit maturity based categorization, and calorie estimation. Datasets are used to train the proposed machine learning model. The dataset used here is a combination of image data containing various types of fruit; here the proposed cost-effective yet powerful fruit quality maintenance method will be useful for fruit vendors and farmers.

Melatonin Pre-harvest Treatments Leads to Maintenance of Sweet Cherry Quality During Storage by Increasing Antioxidant Systems.

Melatonin has been reported to have an important role in fruit ripening, although the effect of pre-harvest melatonin treatment on sweet cherry quality properties during storage is still unknown. In the present experiments, the effects of melatonin (0.1, 0.3, and 0.5 Mm) by foliar spray treatments of ‘Prime Giant’ and ‘Sweet Heart’ sweet cherry trees on fruit quality traits and antioxidants systems during storage was evaluated. Results showed that these treatments reduced weight losses during storage, as well as losses in firmness and titratable acidity. In addition, changes in fruit colour and total soluble solid content were also delayed in fruit from melatonin treated trees with respect to controls. Moreover, in general, total phenolic and anthocyanin concentrations were higher in fruit from treated trees than in those from control ones, either at harvest or during the whole storage period. Finally, the activity of the antioxidant enzymes catalase, ascorbate peroxidase and peroxidase was also enhanced as a consequence of melatonin treatment. Overall results show that pre-harvest melatonin treatment delayed the post-harvest ripening process of sweet cherry fruit, leading to maintenance of their quality properties in optimum levels for consumption 2 weeks more with respect to fruit from control trees. Antioxidant systems, both enzymatic and non-enzymatic ones, were also enhanced by melatonin treatments, which would account for the delay on fruit post-harvest ripening process and fruit quality maintenance during storage.

Low temperature delays degreening of apple fruit by inhibiting pheophorbide a oxygenase (PAO) pathway and chlorophyll oxidation during ripening.

The effects of low temperature (LT) on chlorophyll (Chl) degradation in peel of apple fruit during ripening were investigated. Apples collected at commercial maturity were stored at 4 ± 0.5°C. Our data indicated that LT treatment reduced respiration rate and ethylene production and slowed down softening of apple fruit during ripening. The LT treatment delayed increase in L*, a*, and b* values and decrease in Chl content compared with controls. The LT treatment reduced hydrogen peroxide (H2 O2 ) and malondialdehyde (MDA) contents and decelerated superoxide anion (O2 ·- ) production rate in chloroplast of peel compared with controls during ripening. The LT treatment differentially reduced activities of pheophytin pheophorbide hydrolase (PPH), Mg-dechelatase (MDcase), chlorophyll-degrading peroxidase (Chl-POX), and Chl oxidase, while enhanced SOD activity in chloroplast of peel during ripening. Expression levels of MdHCARa, MdNYC1, MdNYC3, MdNYE1, MdRCCR2, MdPPH1, MdPAO6, MdPAO8, and MdNOL2 in peel were differentially reduced by LT treatment during ripening. Our results indicated that LT treatment might delay Chl degradation through inhibiting PAO pathway and Chl oxidation during ripening of apple fruit. PRACTICAL APPLICATIONS: The LT is a common practice used to extend storage life of apple fruit. Degreening caused by Chl degradation is an integral part of fruit ripening, and elucidating its mechanism is an important subject for fruit quality maintenance. Our data indicated that LT delayed degreening of apple fruit by inhibiting PAO pathway and Chl oxidation during ripening. These results will provide useful information for clarifying molecular mechanisms of LT in regulation of degreening and also for quality maintenance of apple fruit.

The Development of a Green Innovative Bioactive Film for Industrial Application as a New Emerging Technology to Protect the Quality of Fruits.

Today, the most significant challenge encountered by food manufacturers is degradation in the food quality during storage, which is countered by expensive packing, which causes enormous monetary and environmental costs. Edible packaging is a potential alternative for protecting food quality and improving shelf life by delaying microbial growth and providing moisture and gas barrier properties. For the first time, the current article reports the preparation of the new films from Ditriterpenoids and Secomeliacins isolated from Melia azedarach (Dharek) Azadirachta indica plants to protect the quality of fruits. After evaluating these films, their mechanical, specific respirational, coating crystal elongation, elastic, water vapor transmission rate (WVTR), film thickness, and nanoindentation test properties are applied to apple fruit for several storage periods: 0, 3, 6, 9 days. The fruits were evaluated for postharvest quality by screening several essential phytochemical, physiological responses under film coating and storage conditions. It was observed that prepared films were highly active during storage periods. Coated fruits showed improved quality due to the protection of the film, which lowered the transmission rate and enhanced the diffusion rate, followed by an increase in the shelf life. The coating crystals were higher in Film-5 and lower activity in untreated films. It was observed that the application of films through dipping was a simple technique at a laboratory scale, whereas extrusion and spraying were preferred on a commercial scale. The phytochemicals screening of treated fruits during the storage period showed that a maximum of eight important bioactive compounds were present in fruits after the treatment of films. It was resolved that new active films (1–5) were helpful in the effective maintenance of fruit quality and all essential compounds during storage periods. It was concluded that these films could be helpful for fruits growers and the processing industry to maintain fruit quality during the storage period as a new emerging technology.

Dynamic controlled atmosphere: A review of methods for monitoring fruit responses to low oxygen

The storage of fruit at minimum oxygen condition is crucial for optimal fruit quality maintenance. However, the optimal oxygen partial pressure of fruit varies according to several factors such as species, cultivar, harvest maturity, temperature, growing season and storage period. Based on these factors, storage technologies were developed that allow for the detection of the lower oxygen limit (LOL) and the storage of fruit under the lowest optimal oxygen partial pressure. One emerging technology is known as dynamic controlled atmosphere (DCA). Commercially, there are four DCA systems used: [1] DCA based on ethanol production and accumulation (DCA-Eth); [2] DCA based on chlorophyll fluorescence (DCA-CF); DCA based on the respiratory quotient (DCA-RQ) and [4] DCA based solely on CO2 production (DCA-CD). This reviews the recent developments of these DCA systems and their effect on fruit quality. Generally, the storage of fruit under DCA has a positive effect on the overall fruit quality, with regards to reduced physiological disorders and higher flesh firmness maintenance, when compared to controlled atmosphere (CA). Evidence also shows that storing fruit under DCA-RQ and DCA-CD allowed higher volatile compound emission and concentration, which can contribute positively to fruit flavor. The DCA systems are “green storage technologies” because the system enables the increase of storage temperature and thereby saving electrical energy. Storage of apples under DCA maintains an overall fruit quality similar to CA combined with the ripening inhibitor 1-Methylcyclopropen (1-MCP), which is an interesting option for organic fruit storage. Dynamic controlled atmosphere is a recently developed storage technique and is in constant improvement. The latest developed DCA techniques (DCA-RQ and DCA-CD), in contrast to DCA-CF, allow the use of extremely low oxygen levels. In the future, new and multi-sensor DCA systems are under development, which might not just control O2 partial pressure but also temperature and other parameters to allow for more energy efficient but high quality fruit storage systems.

QTL analysis reveals the effect of CER1-1 and CER1-3 to reduce fruit water loss by increasing cuticular wax alkanes in citrus fruit

Postharvest water loss causes fruit softening, wilting, and a decline in quality and commodity value. Cuticular wax is a key barrier against non-stomatal water loss and plays a crucial role in fruit quality maintenance. However, there has been limited research on the genetic basis of fruit wax and postharvest water loss. Here, we found that HJ (Citrus reticulata) and ZK (Poncirus trifoliata) fruit had significant differences in postharvest water loss and cuticular wax. HJ fruit had a lower wax content and a faster water loss, and the main aliphatic wax components were alkanes and aldehydes. By contrast, ZK fruit had a higher wax content and a slower water loss, and the main aliphatic wax components were only alkanes. Correlation analysis revealed that fruit water loss seemed to be correlated with cuticular wax alkane in the F1 pseudo-testcross population of HJ and ZK. Furthermore, through high-density genetic map and bulk segregant analysis, alkanes and fruit water loss were co-localized to QTL3, resulting in the identification of CER1-1 and CER1-3 as the candidate genes. Heterologous overexpression in Arabidopsis revealed that they were involved in alkane synthesis and reduction of leaf water loss. In addition, coating with C28 alkane could reduce postharvest fruit water loss of six citrus varieties. Collectively, we speculated that cuticular wax alkanes might play an important role in limiting fruit water loss. The study provides new insights into the development of coating agents and breeding of citrus varieties with better storage performance.

Molecular basis for optimizing sugar metabolism and transport during fruit development.

Sugars are fundamental metabolites synthesized in leaves and further delivered to fruit in fruit crops. They not only provide "sweetness" as fruit quality traits, but also function as signaling molecules to modulate the responses of fruit to environmental stimuli. Therefore, the understanding to the molecular basis for sugar metabolism and transport is crucial for improving fruit quality and dissecting responses to abiotic/biotic factors. Here, we provide a review for molecular components involved in sugar metabolism and transport, crosstalk with hormone signaling, and the roles of sugars in responses to abiotic and biotic stresses. Moreover, we also envisage the strategies for optimizing sugar metabolism during fruit quality maintenance.

Quality and volatile organic compounds emission alterations in ‘August Flame’ peaches due to low dose methyl bromide fumigation

As all perishable fruit, peaches must be stored in cold temperature during transportation for maintenance of fruit quality. Australian peaches exported to China must undergo fumigation quarantine treatments prior to shipment for biosecurity reasons. ‘August Flame’ peaches were fumigated with methyl bromide (MB) at the low dosage of 18 g/m3 for 5.5 h at flesh temperature of 18 °C, as a biosecurity disinfestation treatment, with a subsequent cold storage period at 2 °C and 4 °C for 5 and 9 d to simulate air freight transportation. Fruit quality parameters measured during shelf life (SL) were: firmness, index of delta absorbance (IAD), ethylene production and respiration. Four families of volatile organic compounds (VOCs) from samples of fruit flesh and skin were analysed along SL: aldehydes, alcohols, esters and lactones. Overall trends in the evolution of quality parameters and VOCs emissions were identified. Fumigation, under our experimental conditions, anticipated the climacteric ethylene peak, but did not affect fruit quality enough to be detrimental for consumption and did not cause skin or internal disorders. During SL aldehydes decreased, lactones increased, alcohols were higher in skin than in flesh, but none of these general trends were clearly affected by the fumigation.

Chlorophyll fluorescence imaging as a tool to evaluate calyx senescence during the ripening of persimmon fruit treated with gibberellic acid

The effect of gibberellic acid (GA) on retarding loss of persimmon firmness and fruit coloration has been previously reported. Nevertheless, information about the effect of this treatment on calyx senescence is lacking. In this study, chlorophyll fluorescence imaging (CFI) was used to evaluate calyx senescence in persimmon fruit treated with GA. At three harvest times, physico-chemical parameters measured on persimmon fruit and CFI parameters (Fo, Fm and Fv/Fm) on calyx sepals were evaluated on the fruit treated once or twice with GA, and also on untreated fruit (CTL). A decline in the chlorophyll fluorescence parameters correlated with calyx senescence and progressed during fruit ripening. Spatial images heterogeneity in the Fm/Fv measurements illustrates senescence and necrosis dynamics, which began in the apical area of sepals and progressed to the basal area. Besides retarding fruit ripening, GA treatments delayed the calyx senescence process, and hence improved external fruit quality maintenance. The CFI parameters measured on the calyx correlated with both external color evolution and firmness loss during fruit ripening. Consequently, these chlorophyll fluorescence parameters could act as a potential non-intrusive tool to determine persimmon harvesting time.

Role of MdERF3 and MdERF118 natural variations in apple flesh firmness/crispness retainability and development of QTL-based genomics-assisted prediction.

SummaryRetention of flesh texture attributes during cold storage is critical for the long‐term maintenance of fruit quality. The genetic variations determining flesh firmness and crispness retainability are not well understood. The objectives of this study are to identify gene markers based on quantitative trait loci (QTLs) and to develop genomics‐assisted prediction (GAP) models for apple flesh firmness and crispness retainability. Phenotype data of 2664 hybrids derived from three Malus domestica cultivars and a M. asiatica cultivar were collected in 2016 and 2017. The phenotype segregated considerably with high broad‐sense heritability of 83.85% and 83.64% for flesh firmness and crispness retainability, respectively. Fifty‐six candidate genes were predicted from the 62 QTLs identified using bulked segregant analysis and RNA‐seq. The genotype effects of the markers designed on each candidate gene were estimated. The genomics‐predicted values were obtained using pyramiding marker genotype effects and overall mean phenotype values. Fivefold cross‐validation revealed that the prediction accuracy was 0.5541 and 0.6018 for retainability of flesh firmness and crispness, respectively. An 8‐bp deletion in the MdERF3 promoter disrupted MdDOF5.3 binding, reduced MdERF3 expression, relieved the inhibition on MdPGLR3, MdPME2, and MdACO4 expression, and ultimately decreased flesh firmness and crispness retainability. A 3‐bp deletion in the MdERF118 promoter decreased its expression by disrupting the binding of MdRAVL1, which increased MdPGLR3 and MdACO4 expression and reduced flesh firmness and crispness retainability. These results provide insights regarding the genetic variation network regulating flesh firmness and crispness retainability, and the GAP models can assist in apple breeding.