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The high-value apple cultivar ‘Honeycrisp’ is prone to bitter pit, a physiological disorder characterized by the development of dark, sunken lesions on fruit particularly towards the calyx-end. Identifying the genetic basis of bitter pit is critical for mitigation of the disorder and development of bitter pit-free varieties. To this end, we performed an RNA sequencing experiment to compare the peel and flesh transcriptomes of healthy and bitter pit-affected ‘Honeycrisp’ fruit, with the objective of identifying bitter pit candidate genes. A similar number of genes were expressed in flesh and peel (~ 27,000), and we detected flesh- and peel-specific expression. Within the flesh and peel datasets, 2.6% and 1% of genes were differentially expressed between healthy and bitter pit apples, respectively. We identified over 1000 differentially expressed genes in both flesh and peel datasets that are distributed throughout the genome, sixteen of which are within a previously identified bitter pit QTL, making them potential candidate genes. Both MdMADS5 and MdIDL1, the orthologs of Arabidopsis APETALA1 and INFLORESCENCE DEFICIENT IN ABSCISSION-LIKE 1, respectively, which are possibly involved in fruit development and organ abscission, stand out as candidate genes for bitter pit, based on their proposed function, differential expression, and location within a bitter pit QTL. The RNA-seq data also revealed that many genes involved with defense response and stress are upregulated in bitter pit-affected tissues. We discuss how these differentially expressed genes could provide important information about the physiology, development, and progression of bitter pit.

7 Pags.- 1 Figs.- 5 Tabls. The definitive version is available at: https://www.ishs.org/acta-horticulturae, A great proportion of losses in apple production can be attributed to fruit physiological disorders, usually revealed during cold storage. These losses are commonly associated with metabolic processes in which calcium is involved. After years of study and experimentation in an attempt to reduce the incidence of Ca-related disorders by exogenous calcium treatments, a study published by Edna Pesis in 2007 opened another research route in this regard. This study, in 'Granny Smith', revealed that applying a treatment of low oxygen at room temperature, a considerable reduction of scald was achieved and pointed to a possible effect on alleviating bitter pit. It was hypothesized that low oxygen treatments may delay the metabolic activity of fruits and also delay ripening, softening and withering. Since 2008, we have continued to deepen into the development of alternative methods of low environmental impact which avoid the use of chemicals. Strategies have been developed for the application of LOT (low oxygen treatment) treatments at room temperature in various apple cultivars, obtaining promising results at the lab and at the semi-industrial scale. In this paper, LOT technology has been validated, this time, on an industrial scale. An Ilerfred system, with monitoring and control of CO2 and O2, was used. The LOT followed by conventional cold storage has proved to be very effective for the control of rots in all cultivars, and was able to effectively control lenticel blotch pit in 'Reinette'. The results of the 2016 campaign compared to those of the two previous seasons allow us to conclude that improvement in shelf life of apples is achieved by combining different LOT conditions with the dynamic controlled atmosphere (DCA) storage technology., This work has been co-funded by y the CDTI (Centro para el Desarrollo Tecnológico Industrial of the Government of Spain) with the support of FEDER in the project “Reducción de fisiopatías en manzana mediante la aplicación de Tratamientos Postcosecha Combinados de Bajo Impacto – ManzImpacto” led by the company SAT DYMA.

The work was performed in the I. V. Michurin Federal Scientifi c Center (Tambov region, Russia) in 2015-2018. The fruits of Sinap Orlovsky variety with high susceptibility to bitter pit, medium – to superfi cial scald and CO2 -skin injuries were used. The main post-harvest strategy of protecting fruits from bitter pit (BP) is storage in a controlled atmosphere (CA), short-term low oxygen storage (10 days, O22 – 1.2-1.5 %, O2 – 1.2-1.5 %), CA-2 (СО22 – 1.2-1.5 %), under conditions of short (10 days) post-harvest impact of controlled factors: temperature 18-20 °С, О2 – 1.2-1.5 %, CO22 ). Ethylene, α-farnesen and its oxidation products (CТ281), phenolic compounds were determined in fruits, losses from bitter pit, scald, CO2 -skin injuries, quality (fi rmness) were estimated. 1-MCP-treatment ensured a low level of ethylene and CT281 accumulation in fruits, protection from scald, preservation of fi rmness in all variants of fruit storage, with maximum effi ciency of variants CA-2, CA-1 and LO2 . Fruit protection from bitter pit was provided by CA-2 technology, a signifi cant reduction of losses – LO2 . When using the technology of CA-2, losses from CO2 -skin injuries, noted in the conditions of CA-1, were excluded. The maximum efficiency of protection of fruits from BP, scald, CO2 -injuries is provided by the developed technology CA-2 (CO22 — 1.2-1.5 %).

‘Honeycrisp’ apple trees are highly prone to biennial bearing and predisposed to bitter pit. The hypothesis that tank mix sprays of ethephon (ETH), naphthaleneacetic acid (NAA), and 1-aminocyclopropane carboxylic acid (ACC) combined with calcium chloride (CaCl2) can mitigate these production problems was tested in a 3-yr study. Mature ‘Honeycrisp’ trees were treated with either three or six summer applications of 150 mg L−1ETH or 5 mg L−1NAA, all tank-mixed with and without CaCl2, or two or five applications of 150 mg L−1ACC (without CaCl2). Treatments were applied at 10-d intervals and initiated between 21 and 26 June. All treatments had little effect on enhancing return bloom of ‘Honeycrisp’. NAA, ETH, and CaCl2all influenced fruit maturity and quality at harvest to varying degrees and across years. Fruit treated with NAA were firmer compared with untreated fruit in 2 out of 3 yr, whereas overall, fruit treated with six sprays of ETH had lower fruit firmness and were more mature. NAA had less influence on fruit quality attributes at harvest than did ETH, and decreased pre-harvest fruit drop (PFD). PFD increased with ETH in 1 out of 2 yr, whereas ACC and NAA both decreased PFD in 1 out of 2 yr. Overall, ETH and NAA, with or without CaCl2, had significant but inconsistent effects on fruit quality and maturity, all dependent on the year and number of applications. Adding CaCl2decreased fruit firmness in 2 out of 3 yr.

Bitter pit is a physiological disorder that can develop during storage and result in major economic losses of susceptible apple cultivars such as ‘Honeycrisp’. Prediction methods to determine the risk of disorder development have focused primarily on mineral composition of the fruit, but there has also been interest in non-mineral based methods. In this study, we have compared non-mineral methods with mineral analyses for bitter pit prediction. Fruit of ‘Honeycrisp’ were harvested three weeks before anticipated commercial harvest and at commercial harvest. Mineral contents in peel from the calyx-end were measured in fruit at both harvest times. In year 1, fruit were kept at 20 °C (passive method), dipped in 2000 mg L−1 2-chloroethylphosphonic acid (ethylene method) or 0.8 M MgCl2 (Mg method). Treated fruit were then kept at 20 °C for three weeks. At commercial harvest, fruit were stored at 0.5 or 3 °C with and without 1 week of conditioning at 10 °C. The Mg method showed toxicity on the fruit, which was hard to distinguish from bitter pit. Therefore, in year 2, only the passive and ethylene methods were used, and fruit from the commercial harvest were stored at 3 °C with or without conditioning. In year 3, only the passive method was used because of its simplicity and lack of registration of ethephon for this purpose. Fruit from the commercial harvest of 38 orchards in three growing regions were stored at 3 °C after conditioning. Fruit were stored for two months in year 1 and four months in years 2 and 3, and assessed after 4 d at 20 °C. Multivariate analysis shows that the passive and ethylene methods for fruit harvested three weeks before the anticipated harvest had higher or similar correlations with the actual bitter pit after cold storage than those from minerals. Although actual bitter pit incidence was higher than that predicted from the passive method, the method results in predictions that are similar to mineral-based predictions, and also is more straightforward for commercial application.

Background Frequent pesticide treatments in fruit orchards increase hazards for workers, consumers and the environment. Moreover, the indiscriminate and excessive use of pesticides often induces resistance in pests. In the past few years, physical exclusion strategies have been proposed as an alternative for the control of insect pests. The goal of this study was to evaluate the effectiveness of anti-hail photoselective netting in protecting apples against key and emerging pests, as well as the impact on beneficial arthropods, fungal diseases and fruit quality. Results In netted plots, a significant reduction in pest populations, i.e. fruit moths, Halyomorpha halys (Stal) and Drosophila suzukii (Matsumura), was recorded in comparison with un-netted controls. Moreover, the damage on fruits caused by H. halys was reduced up to 62% compared with insecticidal treatments. The net did not negatively affect the abundance of predators and the incidence of post-harvest rot. In addition, the incidence of bitter pit on apple was reduced up to 52%. Furthermore, fruit quality was unaffected by the net coverage (both at harvest and after 4 months of storage). Conclusion Anti-hail photoselective pearl netting proved a promising exclusion system that can prevent attack by more than one insect pest at a time, allowing for a strong reduction in insecticide treatments and relative costs. At the same time, the netting did not negatively influence the presence of predators, the incidence of fungal disease or fruit quality. © 2019 Society of Chemical Industry.

Flavonoids are an important group of polyphenolic compounds which are widely distributed throughout the plant kingdom especially in colored fruits and flowers. They play important roles in many plant biological functions and have therapeutic effect on many chronic diseases in humans. The flavonoid biosynthesis and productivity in plants could be stimulated by many biotic and abiotic factors. Bitter pit in apple is an important physiological disorder in apple production, which consequently affects the quality of apple fruits and causes significant economic losses. This study was aimed to investigate the influence of bitter pit on the flavonoid contents in apple fruits and its molecular biological mechanism, so as to explore the alternative bioresource of flavonoids for medical application in human chronic diseases. The total flavonoid content was determined using the aluminum chloride colorimetric method. The result showed that the total flavonoid content in bitter-pit apple fruits (BG) were 4.28-fold as that in healthy apple fruits (JKG). By RNA sequencing, 257.002 and 225.713 M raw reads containing 38.55 and 33.857 Gb raw bases were obtained from JKG and BG respectively, after trimming the adapter sequences, primers, Ns, and reads with quality scores below 30, 226.702 and 202.951 M clean reads containing 32.807 G and 29.626 nucleotides were obtained respectively, their base ratios with quality values higher than 20 and 30 in reads (Q20 and Q30) were more than 98.3% and 95.0%, respectively. By miRNA sequencing, 4331 clean reads associated with 3753 target genes (2571 upregulated and 1181 downregulated) were obtained. After annotation, a total of 41894 RNAs were obtained, of which, 15852 were known transcripts and 26042 were novel transcripts. Among the obtained transcripts, there were 33582 mRNAs (12645 known and 20937 novel), 1860 lncRNAs (0 known and 1860 novel), 98 circRNAs (52 known and 46 novel), 5894 miRNAs (3017 known and 2877 novel), 322 other type of RNAs(0 known and 322 novel) and 138 unknown type of RNAs (138 known and 0 novel). Based on Gene Ontology (GO) gene functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, 2632 differentially expressed genes (DEGs) were obtained from JKG vs. BG comparison, in which, 2080 DEGs were upregulated and 552 were downregulated. Among the obtained DEGs, 26 DEGs (2 downregulated and 24 upregulated) were involved in flavonoid biosynthesis [ko00941], all of them are mRNAs, there were no lncRNAs, circRNAs and miRNAs related to flavonoid biosynthesis. Then, 8 of the 26 DEGs [ CYP98A3 (1), CYP98A3 (2), BADH , DAT , MdHCT (1), MdHCT (2), CHI (1) and CHI (2)] with fold change>1.0 (1.43–29.42) were selected for qRT-PCR validation, the result exhibited the consistent expression patterns with that of RNA-seq analysis ( R 2=0.8551), that is, the expression of the 8 DEGs were upregulated with the BG/JKG ratio of 1.05–7.17 in JKG vs BG comparison, and the ratios of qRT-PCR relative expression level were less than the fold change of RNA-seq FPKM value except DAT . The results of this study showed that the flavonoid biosynthesis and accumulation in apple fruits was significantly stimulated by bitter pit disease, which provided new insights into the influence of bitter pit on the flavonoid biosynthesis and accumulation in apples and indicated that the bitter-pit apples could be use as the potential bioresource of flavonoids for therapeutic utilization in human chronic diseases.

Honeycrisp apple trees are highly prone to biennial bearing and bitter pit (BP). This 3-y study tested the hypothesis that tank mix sprays of ethephon (ETH), naphthaleneacetic acid (NAA), and 1-aminocyclopropane carboxylic acid (ACC) combined with calcium chloride (CaCl2) can mitigate these production problems. Mature ‘Honeycrisp’ were treated with either three of six applications of 150 mg.L-1 ETH, 5 mg.L-1 NAA or two of five applications of 150 mg.L-1 ACC, all tank-mixed with and without CaCl2 and applied at 10-d intervals starting 21–26 June over three growing seasons. Fruit cortical tissue nutrient concentrations were influenced by applications of CaCl2, ETH, NAA, and ACC. In one year, Ca concentrations were significantly higher in fruit from trees treated with six sprays of ETH or NAA with CaCl2 compared with the untreated control. Compared with untreated trees, fruit Ca concentrations were 115% and 148% higher with three and six applications, respectively. Applications of CaCl2 significantly reduced the incidence and severity of BP post-harvest in two of three years when fruit tissue Ca levels were low. ETH alone also increased the incidence and severity of BP two-fold compared with the control, while early season sprays of NAA reduced BP incidence and severity compared with the untreated control. High and similar levels of BP incidence and severity were observed when six sprays of NAA were applied with or without Ca. Fruit tissue K levels were generally reduced with the addition of CaCl2, and within 1 year, K levels were higher in fruit treated with ACC. Fruit Mg concentrations generally decreased with the addition of Ca or NAA. Six applications of ACC resulted in a 30-fold increase in fruit Mg concentrations compared to the untreated control. Tank mixing CaCl2 with the flower-promoting bio-regulators ETH and NAA proved to effectively reduce BP and increase fruit tissue Ca levels. This approach would offer cost savings when repeat sprays of each are required on a bi-weekly basis.

Malus ×domestica Borkh. cv. Honeycrisp has been widely planted in North America during the past two decades. However, it is susceptible to many disorders that result in high postharvest losses. Excessive vegetative vigor in apple trees can reduce fruit calcium (Ca) concentrations and increase bitter pit incidence in apple fruit. Plant growth regulators are used routinely in tree fruit orchards to control vegetative growth to increase light penetration into the canopy. The objective of this study was to determine whether shoot growth inhibition using the application of prohexadione-calcium (P-Ca; Apogee®) or stimulation via application of gibberellic acid (GA3; ProGibb®) affected bitter pit incidence in ‘Honeycrisp’ apple. In 2016 and 2017, the experiment was conducted in a commercial ‘Honeycrisp’ orchard with five treatments [untreated control, 62.5 mg·L–1 P-Ca (low P-Ca); 125 mg·L–1 P-Ca (high P-Ca); 16 mg·L–1 GA3 (low GA3); and 32 mg·L–1 GA3 (high GA3)]. Treatments were applied twice during the growing season. Shoot length and the number of internodes for new growth were measured 4 weeks apart after treatment. Overall yield and fruit quality were assessed at harvest, and bitter pit incidence was assessed after 4 months of storage. Low and high P-Ca rates limited shoot growth extension; high GA3 increased shoot extension compared with the untreated control. However, the number of internodes did not change substantially for each shoot. The number of internodes is one of the primary factors affecting leaf area and, consequently, the transpiration balance between fruit and leaves. In both years, treatments with either GA3 or P-Ca did not affect fruit elemental concentration or bitter pit incidence. These results indicate that growth-inhibiting plant growth regulators that reduce shoot extension may not be useful for managing bitter pit incidence in ‘Honeycrisp’ apple.

Aim of study: A portable VIS/NIR spectrometer and chemometric techniques were combined to identify bitter pit (BP) in Golden apples. Area of study: Worldwide Material and methods: Three different classification algorithms – linear discriminant analysis (LDA), quadratic discriminant analysis (QDA) and support-vector machine (SVM) –were used in two experiments. In experiment #1, VIS/NIR measurements were carried out at postharvest on apples previously classified according to 3 classes (class 1: non-BP; class 2: slight symptoms; class 3: severe symptoms). In experiment #2, VIS/NIR measurements were carried out on healthy apples collected before harvest to determinate the capacity of the classification algorithms for detecting BP prior to the appearance of symptoms. Main results: In the experiement #1, VIS/NIR spectroscopy showed great potential in pitted apples detection with visibly symptoms (accuracies of 75–81%). The linear classifier LDA performed better than the ultivariate non-linear QDA and SVM classifiers in discriminating between healthy and bitter pitted apples. In the experiment #2, the accuracy to predict bitter pit prior to the appearance of visible symptoms decreased to 44–57%. Research highlights: The identification of apples with bitter pit through VIS/NIR spectroscopy may be due to chlorophyll degradation and/or changes in intercellular water in fruit tissue. info:eu-repo/semantics/publishedVersion

Digital image processing with associated sensing elements operating in the broad range of the electromagnetic spectrum has emerged as a prominent technique in almost every field for making crucial decisions. Although the imaging technique originated more than a century ago, tremendous growth has been seen in the last two decades, especially with the growth in the hardware and software industries providing a significant boost. Imaging was originally developed for applications in the medical field and remote sensing. As technology grew, the technique has occupied an irreplaceable part in every walk of life. X-ray imaging has been explored for inspecting the interior of horticultural commodities. The intensity of energy exiting the product is dependent upon the incident energy, absorption coefficient, density of the product, and sample thickness. Some of the internal disorders that could be detected non-destructively include cork spot, bitter pit, watercore, and brown core for apple; blossom end decline, membranous stain, black rot, seed germination and freeze damage for citrus; and hollow heart, bruises, and perhaps black heart for potato.

Bitter pit has been described as one of the most important physiological disorders of apple fruit whose symptoms appear late in the season and during storage and which can cause high economic losses. The negative relationship between bitter pit and mineral contents in fruit led to develop prediction models. However, these models are based on mineral content close to harvest and can only provide valuable information at harvest. Aim of this study was to assess for three years the accuracy of different bitter pit prediction methods along fruit development, based on either Ca content in fruit (at 90 days before harvest and at harvest) or induction of symptoms (Mg infiltration, ethephon dip, passive method) at three levels: the overall accuracy, the accuracy of bitter pit incidence prediction (true positive rate), and the accuracy of non-bitter pit prediction (true negative rate). These three accuracies were considered together to know the real prediction risk of each method. From the results obtained, we proposed and validated, for other two years more, a detailed protocol to predict bitter pit which incorporated fruitlet analysis at 90 DBH, in order to gain prediction time, and the passive method at 40 and 20 DBH, in order to reduce the proportion of negative samples that were incorrectly classified. info:eu-repo/semantics/acceptedVersion

Calcium is one of the most poorly reutilized nutrients. Its deficiencies cause various physiological disturbances and, consequently, reduce the quantity and quality of yields. Reduced content of Ca2+ ions in cells leads to development of, e.g., bitter pit in apples. Efficient and instantaneous mitigation of Ca2+ deficiencies is provided by foliar feeding. There are no detailed data on the effect of foliar feeding with various calcium forms on the cell structure or on the microanalysis and mapping of this element in apple fruit cells. Therefore, we carried out comparative studies of the ultrastructure of epidermis and hypodermis cells, to assess the content and distribution of calcium in the cell wall, cytoplasmic membrane, cytoplasm, and precipitates of Malus domestica Borkh. &lsquo, Szampion&rsquo, fruit exposed to four Ca treatments, including the control with no additional Ca supplementation (I) and foliar applications of Ca(NO3)2 (II), CaCl2 (III), and Ca chelated with EDTA (IV). Light and transmission electron microscopy and an X-ray microanalyzer were used and showed a beneficial effect of calcium preparations on the ultrastructure of fruit epidermis and hypodermis cells, manifested in the presence of a normally developed cell wall with a regular middle lamella, preserved continuity of cytoplasmic membranes, and stabilized cell structure. In the selected elements of apical epidermis cells, the highest level of Ca2+ ions was detected in the middle lamella, cell wall, plasmalemma, and cytoplasm. The highest increase in the Ca2+ content in these cell constituents was recorded in treatment IV, whereas the lowest value of the parameters was noted in variant III.

Preharvest nutrient applications have major impacts on apple tree mineral status, productivity, and fruit quality attributes. Despite the wide use of calcium chloride (CaCl2) for improving apple fruit quality attributes particularly bitter pit, application of amino acid, polyamine and phosphite-based nutrients (Sysstem series) have become popular in the past decade.

Shade cloth is commonly used to reduce incident light in apple (Malus domestica [Suckow] Borkh.) orchards. Nevertheless, this technology can generate changes in plant physiology that affect tissue nutritional composition and cause fruit nutritional disorders. The effect of shade cloth on the nutritional concentration of six macroelements and six microelements on leaves, six macronutrients in the fruits of ‘Fuji’ apples, and bitter pit incidence was assessed in a study conducted in a commercial orchard in south-central Chile for three seasons. Two treatments (control without shade cloth and 30% shade cloth cover) were evaluated with five replicates in a split plot design. Averaged results for the three seasons showed that shade cloth increased Mg, Mn, and Zn concentrations in leaves by 0.02%, 40 mg kg-1, and 5.5 mg kg-1, respectively, and decreased K, Mg, and S concentrations in fruits by 12, 0.35, and 0.38 mg 100 g-1 fresh fruit, respectively. Bitter pit incidence was not affected by shade cloth (values between 0.3% and 6.6%), but seasonal conditions did affect this abiotic disorder. In conclusion, the use of shade cloth in apples did not affect bitter pit incidence, but it caused some changes in leaf and fruit nutritional concentration.

Irrigation is critical to maintain plant growth and productivity in many apple-producing regions. &lsquo, Honeycrisp&rsquo, apple characteristically develops large fruit that are also susceptible to bitter pit. Limiting fruit size by restricting irrigation may represent an opportunity to control bitter pit in &lsquo, For three seasons, &lsquo, trees were subject to water limitations in 30-day increments and compared to a fully watered control. Water limitations were imposed from 16&ndash, 45, 46&ndash, 75, and 76&ndash, 105 days after full bloom (DAFB). Soil moisture for the well-watered control was maintained at 80&ndash, 90% of field capacity for the entire season. For two years, physiological measurements were made every 15 days from 30 to 105 DAFB. Fruit quality, bitter pit incidence, shoot length, and return bloom were also measured to assess impacts on growth and productivity. When water was limited, stomatal conductance and net gas exchange were lower compared to the well-watered control and stem water potential decreased by 30&ndash, 50% throughout the growing season. Early season water limitations had a lower impact on plant response to abiotic stress compared to late-season limitations. Overall, water deficits during fruit expansion phases contributed to fewer large fruit and decreased overall bitter pit incidence with no negative effects on fruit quality.

Bitter pit is a physiological disorder that occurs in pome fruit, mainly apples (Malus domestica) and pears (Pyrus communis). Although bitter pit was believed to be caused by pathogens, it is now commonly agreed that any factor that leads to low calcium (Ca) concentration or high ratios of certain mineral elements in the fruit tissue, particularly, nitrogen (N), potassium (K), and/or magnesium (Mg) to Ca can induce bitter pit disorder.

Calcium (Ca) deficiency disorders in apple fruit have been associated with high gibberellins (GAs) activity in the tree. This study was carried out to assess the effects of treatments of ?Braeburn? apple trees with prohexadione-calcium (ProCa, an inhibitor of GAs biosynthesis) or gibberellins (GA4+7) on vegetative growth of the trees and postharvest incidence of Ca-related physiological disorders and decay in the fruit. ProCa (300?mg?L-1) or GA4+7 (300?mg?L-1) treatments were applied post-bloom (PB) and preharvest (PH). PB treatments started 15 days after full bloom (DAFB), with one application every week and six applications in total. PH treatments started five weeks before anticipated harvest (125 DAFB), with one application every week and four applications in total. Control trees were left untreated. When applied PB, ProCa reduced and GA4+7 promoted vegetative growth of the trees. ProCa PB delayed the impairment of xylem functionality (at the proximal region of the fruit) during fruit growth on the tree. Treatments had no effect on fruit weight, pectinmethylesterase (PME) activity or the expression of CAX3, CAX6 and V-ATPase (transporters of Ca into the vacuole) genes assessed in the external cortical tissue at the distal end of the fruit at harvest. When sprayed PB, ProCa increased the total Ca content and reduced K/Ca, Mg/Ca, N/Ca, (Mg?+?K)/Ca and (K?+?Mg?+?N)/Ca ratios in the flesh at the distal portion of the fruit, compared to the treatment with GA4+7, but without differing from the control. In general, ProCa application PB or PH reduced the expression of Ca-ATPase1, Ca-ATPase2, H+-PPase and CAX2 (Ca transporters into the vacuole) genes, increased total water?soluble Ca and reduced electrolyte leakage in the fruit at harvest. After two months of cold storage followed by five days of shelf-life, the incidence and severity of bitter pit (BP) was lower on fruit from trees treated with ProCa PH, and higher on fruit from trees treated with GA4+7 PB. GA4+7 PB also increased the incidence of skin cracking and decay in the fruit. The results showed that ProCa application represents a feasible tool to reduce the incidence of BP. However, ProCa is more effective to reduce BP if applied weekly for five week before harvest. Made available in DSpace on 2020-01-20T18:08:47Z (GMT). No. of bitstreams: 1 Postbloomandpreharvesttreatment2019.pdf: 2004561 bytes, checksum: 11017528f46d0bb2569a8901f722d714 (MD5) Previous issue date: 2019

The influence of foliar fertilization on calcium concentrations in leaves and apple fruit tissues ( flesh and skin) has been studied in the field experiment with mature ‘Imrus’ and ‘Sinap Orlovsky’ apple trees varieties in 2011-2015 growing seasons. The experiment was conducted in pedoclimatic conditions of forest-steppe of the Central Russian Upland (Orelregion). The experimental orchard is on loamy grey forest soil with high calcium content 4,8 ± 0,5 mmol/100g. The separate and combined foliar nutrient treatments with Н 3 ВО 3 (0,1 %), К 2 SО 4 (0,3 %) and СаСl 2 (1 %) were applied five times during the vegetation period. The results showed that meteorological conditions and yield load were the main factors affecting on calcium concentrations in leaves and fruit flesh and skin of both varieties. Foliar fertilization regardless of the calcium presence in the composition of fertilizers to a greater extent changed the calcium content in apple fruit tissues, then in leaves. All treatments one way or another resulted in changing of calcium concentration in fruit tissues, but in different years the contrary effect of the same treatments was observed. The variety ‘Sinap Orlovsky’ (known for its high susceptibility to bitter pit) was more responsive to foliar treatments, than the variety ‘Imrus’. In 2013 fruits of both varieties were remarkable for the least calcium concentrations (3,87±0,25 mg/100 g of fresh wt), and it was two times smaller than in the previous and following growing seasons. In the same year essential increase of calcium concentration in fruits was not observed after foliar fertilization, but some treatments resulted in essential reduce of this index. Despite of high soil calcium content calcium concentrations in leaves were low for both varieties: ‘Sinap Orlovsky’ – 0,75±0,08 %; ‘Imrus’ 1,08±0,14% dry wt. Signi fi cant negative correlations (R= -0,46…-0,34; P

In this study the effects of hexanal, a potential postharvest preservative, contained within ‘Enhanced Freshness Formulation’ (EFF), on apple ripening was investigated. EFF was sprayed before harvest on ‘Honeycrisp’ apples in commercial orchards within the Niagara region of Ontario, and its impact on ripening was compared to EFF without hexanal, EFF with calcium chloride and a control treatment in a randomized complete block design. There were no significant differences among treatments in fruit retention and most fruit quality measurements. However, there was an increase in TSS and a reduction of bitter pit in apples treated with EFF and EFFCA. Gene expression levels were evaluated for 18 genes that could be affected by hexanal application. EFF application reduced gene expression levels of phospholipase-D (PLD), ethylene, cell wall and calcium related genes. These findings suggest that hexanal plays an important role in the slowing of ripening throughout the shelf life of ‘Honeycrisp’ apples. Support and funding for this project was provided by Global Affairs Canada through the Canadian International Food Security Research Fund (CIFSRF). A thank you to additional assistance provided by the department and various donors in the form of scholarships: Margaret and Angus Hamilton Apple Research Scholarship, Keith R. Collver Scholarship and Hoskins Scholarship.

The preharvest application of Ca-containing foliar fertilizers can reduce the incidence of bitter pit (BP) in apples and improve fruit quality by increasing the Ca content and decreasing both the N content and the N/Ca ratio in fruits. In this study, we aimed to investigate the control efficacy of Ca-containing fertilizers on the incidence of BP and their effects on the Ca and N contents in bagged 'Fuji' apples by spraying foliar fertilizer containing calcium chloride (CaCl2 ), calcium nitrate [Ca(NO3 )2 ] or calcium formate [Ca(HCOO)2 ] at an early stage, five days after full bloom (DAFB) and 40 DAFB, and at a late stage, 80 DAFB and 125 DAFB.; Results: The incidences of BP were reduced significantly by 43.2-73.0%, and the efficacy of spraying at an early stage was significantly higher than that of spraying at a late stage. The Ca content of bagged apple fruits increased whereas the N content and N/Ca ratio decreased after spraying Ca-containing foliar fertilizers; however, the Ca content, N content and N/Ca ratio of apple leaves were differentially influenced.; Conclusion: Foliar fertilizer containing CaCl2, Ca(NO3 )2 or Ca(HCOO)2 can be used at an early stage to control BP in apple and improve the quality of bagged apple fruits. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

The potential of dynamic controlled atmospheres (DCA) as a non-chemical treatment for maintaining the postharvest quality of apples during long-term cold storage has been an interest of researchers for decades. This article reviews the recent developments in DCA technology for storage of apples. The effects of DCA on physiological disorders, physico-chemical and sensory quality are discussed. Moreover, negative effects associated with DCA technology are also discussed. The study has shown that DCA maintains apple postharvest quality by reducing respiration rate and ethylene production. Ethylene-mediated physiological disorders such as superficial scald are completely suppressed by DCA storage. However, the effect of DCA on bitter pit incidence needs further investigation. The review also showed that fruit firmness and colour retention is considerable high in DCA stored apples. Although DCA maintains both the physico-chemical and organoleptic quality of apples, the high risk of CO2 and low O2 injury in DCA stored fruit remains a concern. Further research is required to refine and improve the DCA technology in order to minimize the risk of CO2 and low O2 injury during longterm storage.

This work was carried out to investigate the mechanisms regulating fruit calcium (Ca) content and susceptibility to bitter pit (BP) in 'Fuji' and 'Catarina' apples (cultivars with low and high susceptibility to BP, respectively). Fruit of both cultivars were harvested at commercial maturity in an orchard located in southern Brazil, and assessed for xylem functionality and lenticels pore area (mm2 mm-2 of skin) at the distal end. Fruits were also cold stored for four months (0.0±0.5°C/95% RH) and then separated in lots without and with BP. Fruits of both cultivars without and with BP were assessed at the distal (blossom end), middle (equatorial region) and proximal (peduncle end) portions for pectin methylesterase (PME) activity in the skin and flesh tissues, and at distal portion for peroxidase (POD) and ascorbate peroxidase (APX) activities and Ca content in the flesh tissue. At harvest, 'Catarina' apples had lower xylem functionality and lower lenticels pore area at the distal end than 'Fuji' apples. 'Catarina' had higher incidence of BP after cold storage (12.7%) than 'Fuji' (2.3%). In both cultivars, fruit with BP had lower Ca content in the flesh at the distal end. Fruits with BP showed at the distal region higher POD activity in the flesh in 'Fuji' and higher PME activity in the skin in 'Catarina' than fruit without BP. Only in 'Fuji', fruits with BP had higher PME activity in the flesh tissue at the middle and distal portion than fruits without BP. The results show that impairment of xylem functionality, and reduced lenticels pore area and high PME activity in the skin tissue at the distal portion of the fruit might reduce fruit Ca content and increase the incidence of BP, especially in 'Catarina', a cultivar highly susceptible to the disorder.

Introducción: El calcio, es un nutriente importante para aumentar la calidad y rendimiento en los cultivos hortofrutícolas, ya que es considerado como el mineral más importante para la calidad de las manzanas, algunas investigaciones han demostrado su incidencia en la reducción de ciertas alteraciones fisiológicas (bitter pit, corazón acuoso y la descomposición interna), conseración de la firmeza de la pulpa y prevenir la incidencia de podredumbres fúngicas. El objetivo del presente estudio fue evaluar el efecto del subproducto industrial carbonato de calcio (CaCO3) en los atributos de calidad, contenido fenólico y capacidad antioxidante de manzanas cvs Golden Delicious y Top Red.Método: Se utilizaron árboles de 21 años de edad cultivados en la región de Cuauhtémoc, Chihuahua. México, los tratamientos fueron Kg ha-1 de CaCO3 (y su equivalente en Ca por ha): Testigo sin aplicación T1, 282.70 (100) T2;565.30 (200) T3; 847.90 (300) T4; 1130.60 (400) T5;1413.20 (500) T6; 1695.90 (600) T7; 1978.50 (700) T8; 2261.20 (800) T9;2543.80 (900) T10; 2826.50 (1000) T11; 3957.00 (1400) T12 respectivamente. Las variables evaluadas fueron: contenido de Ca, rendimiento, diámetro, peso, color, firmeza, sólidos solubles, acidez titulable, relación SST/acidez titulable, fenoles totales y capacidad antioxidante por el metódo de DPPH. Resultados: Los resultados mostraron diferencias estadísticas (p ≤ 0.05) entre cultivares, los tratamientos incrementaron el contenido de Ca, la firmeza fue significativamente más alta, el cultivar Top Red presentó los valores más altos de compuestos fenólicos con 3.587 mg g-1 de ácido gálico, mientras que el cultivar Golden Delicious presentó la mayor capacidad antioxidante con 2.27 mg g-1 de Trolox. Discusión o Conclusión: Se concluye que la aplicación de CaCO3 influyó en los parámetros de calidad, contenido de compuestos fenólicos y capacidad antioxidante en las cultivares Top Red y Golden Delicious.

Susceptibility of apple fruit to physiological storage disorders is affected by both pre- and postharvest factors that influence their ethylene production. In this study, the inhibitor of ethylene perception, 1-methycyclopropene (1-MCP), applied before and after harvest, has been used to investigate the interactions between ethylene and development of physiological disorders in ‘Honeycrisp’ apples during storage. Preharvest 1-MCP (Harvista™) was applied to trees, either 2 weeks (early), 1 week (late), at 1 and 2 weeks (repeated), or at double rate 1 week, before first commercial harvest. Fruit were then untreated or treated with postharvest 1-MCP (SmartFresh®) and stored at 0.5 °C, or conditioned at 10 °C for 7 d and then stored at 3 °C (C + 3 °C), for 20 weeks. Fruit quality and physiological disorders were assessed after 4 d at 20 °C. Fruit from all preharvest 1-MCP treatments had lower internal ethylene concentrations (IECs) and were greener as indicated by higher IAD values compared with untreated controls, while effects on starch pattern indices (SPI) were inconsistent. After storage, preharvest 1-MCP -treated fruit were firmer than untreated fruit, but effects of the different application timings were inconsistent. Effects of postharvest 1-MCP on IEC and IAD values were greater at 0.5 °C than at C + 3 °C. High incidences of core browning and vascular browning developed during storage, especially in the preharvest 1-MCP-treated fruit. Soft scald was reduced by preharvest 1-MCP treatments compared with control. In the C + 3 °C storage treatment, preharvest 1-MCP-treated fruit had a higher bitter pit incidence than in control fruit, but less skin wrinkling and senescent breakdown. Postharvest 1-MCP treatment of preharvest 1-MCP fruit slightly decreased bitter pit incidence while greatly increasing that of core browning and leather blotch, and sometimes flesh browning and carbon dioxide injury. This study shows that pre- and postharvest inhibition of ethylene perception by 1-MCP can have marked effects on storage disorders that are affected by fruit maturity and storage temperatures.

γ-Aminobutyric acid (GABA) can accumulate in apple fruit in response to stress, but little is known about the responses of fruit to GABA treatments. The hypothesis that GABA would inhibit physiological disorder development in ‘Honeycrisp’ apples has been tested in a three-year study. In 2015, ‘Honeycrisp’ apple trees were sprayed with 40 mM GABA 2 and 4 weeks before harvest, and harvested fruit stored at 0.5 °C, a chilling injury-inducing temperature, or 3 °C, for 4 months. In 2016, the same GABA concentration was sprayed on trees at 1 and 2 weeks before harvest and fruit stored at 0.5 °C for 5 months. In the 2017 season, trees were sprayed with 40 mM GABA and 0.12% CaCl2, either alone or in combination, at 1, 2, and 3 weeks before harvest. Postharvest treatments were also applied by dipping fruit in 100 mM GABA and/or 2% CaCl2 at harvest. Fruit were stored in air at 3 °C after 1 week of conditioning at 10 °C, or at 0.5 °C continuously for 5 months. In the first two years, GABA field treatments had little effect on harvest indices, but inhibited soft scald development depending on spray timing. In year 3, GABA provided no benefit, either alone or in combination with CaCl2. Bitter pit incidence was increased by the GABA/CaCl2 combination in fruit from one orchard block, but at times decreased in fruit from a second orchard block. Treatment of fruit by dipping with GABA after harvest decreased soft scald, bitter pit or senescent breakdown incidence in one orchard block, and in combination with CaCl2 inhibited bitter pit to the same extent as CaCl2 alone. Further research is warranted to better understand the effects of GABA on apple fruit metabolism.

In climates such as New York State, USA, fruit quality (taste and bitter pit incidence) of "Honeycrisp" apple varies significantly from year to year. Our research with Honeycrisp? indicates that when crop load is too high the tree cannot supply sufficient carbon, and other nutrients to give optimum fruit quality (taste, appearance and storageability). Similarly if weather patterns are cloudy, tree carbon acquisition is reduced and carbon supply for fruit growth is limited resulting in less than adequate resources for optimum fruit quality. In an attempt to predict "Honeycrisp' eating quality and bitter pit incidence post storage we began a study in 2013 where we measured fruit quality characteristics at harvest of 30 orchards in western NY and 20 orchards in northern NY and correlated them with eating quality post storage after 4.5 months in air. The dry matter concentrations at harvest among orchards ranged from 11 to 18%. Neither fruit dry matter no concentration or fruit mineral concentrations (N, Ca and Ca/N and K+Mg/Ca ratio) were predictive of post-storage fruit quality. Fruit Ca concentration was also not predictive of post storage fruit bitter pit. Fruit samples were also treated with MCP or left untreated at harvest. MCP resulted in a small but significant improvement in fruit crunchiness, reduced disagreeable flavors and increased liking score of ?Honeycrisp? fruits. Keywords: fruit mineral concentration, fruit Ca concentration, liking score, bitter pit, MCP Made available in DSpace on 2019-05-01T00:43:01Z (GMT). No. of bitstreams: 1 Robinsonetal2017.pdf: 574135 bytes, checksum: 74a3a0e80bfe4e5fb2d7c05b3e1c13b2 (MD5) Previous issue date: 2017

‘Honeycrisp’ (Malus domestica Borkh.), a premium applecultivar, is highly susceptible to bitter pit and decline in quality during long-term storage. In order to enhance the quality, an aqueous composition containing hexanal was applied as a preharvest spray. The effects of hexanal were assessed on the treated fruit and compared with HarvistaTM (a sprayable 1-Methylcyclopropene based commercial formulation) applied and control fruit under both cold (2.5 °C, four months) and cold after room temperature storage (20 °C, 14 days) conditions. Color, firmness, and total soluble solids (TSS) did not show a significant change in response to any treatment at harvest, while abscisic acid (ABA) significantly reduced and tryptophan increased in response to hexanal, compared to HarvistaTM and control. The treatment effects on quality traits were observed during storage. Both hexanal and HarvistaTM sprayed apples had higher TSS under both cold and room temperature storage. In addition, both sprays enhanced firmness at room temperature storage. However, the effects of sprays on other quality traits showed a different pattern. Apples sprayed with hexanal had lower phospholipase D enzyme (PLD) activity, lower incidence of bitter pit, and decreased expression of MdPLDα1 compared to HarvistaTM and control. On the other hand, HarvistaTM treated fruit produced lower ethylene. Both sprays decreased the expression of MdPLDα4, MdCaM2, MdCaM4 and MdCML18 genes. Generally, PLD alpha has a direct role in promoting fruit senescence, whereas the calcium senor proteins (CaM/CMLs) may involve in fruit ripening process via calcium and ethylene interactions. Therefore, improved postharvest qualities, including the lower incidence of bitter pit in hexanal treated ‘Honeycrisp’, may be associated with lower membrane damage due to lower PLD enzyme activity and decreased expression of MdPLDα1 and MdPLDα4 genes throughout the storage period.