Near infrared (NIR) spectroscopy allows rapid estimation of quality traits in fresh fruit. Several portable spectrometers are available in the market as a low-cost solution to perform NIR ...spectroscopy. However, portable spectrometers, being lower in cost than a benchtop counterpart, do not cover the complete near infrared (NIR) spectral range. Often portable sensors either use silicon-based visible and NIR detector to cover 400–1000 nm, or InGaAs-based short wave infrared (SWIR) detector covering the 900–1700 nm. However, these two spectral regions carry complementary information, since the 400–1000 nm interval captures the color and 3rd overtones of most functional group vibrations, while the 1st and the 2nd overtones of the same transitions fall in the 1000–1700 nm range. To exploit such complementarity, sequential data fusion strategies were used to fuse the data from two portable spectrometers, i.e., Felix F750 (~400–1000 nm) and the DLP NIR Scan Nano (~900–1700 nm). In particular, two different sequential fusion approaches were used, namely sequential orthogonalized partial-least squares (SO-PLS) regression and sequential orthogonalized covariate selection (SO-CovSel). SO-PLS improved the prediction of moisture content (MC) and soluble solids content (SSC) in pear fruit, leading to an accuracy which was not obtainable with models built on any of the two spectral data set individually. Instead, SO-CovSel was used to select the key wavelengths from both the spectral ranges mostly correlated to quality parameters of pear fruit. Sequential fusion of the data from the two portable spectrometers led to an improved model prediction (higher R2 and lower RMSEP) of MC and SSC in pear fruit: compared to the models built with the DLP NIR Scan Nano (the worst individual block) where SO-PLS showed an increase in R2p up to 56% and a corresponding 47% decrease in RMSEP. Differences were less pronounced to the use of Felix data alone, but still the R2p was increased by 2.5% and the RMSEP was reduced by 6.5%. Sequential data fusion is not limited to NIR data but it can be considered as a general tool for integrating information from multiple sensors.
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•First time sequential modelling NIR data for fruit analysis is presented.•Data from two portable spectrometer was fused to improve predictive performance.•NIR and SWIR spectral ranges carry complementary information.•Sequential variable selection identified subset of complementary wavelengths.
Anthocyanin concentration is the key determinant for red skin color in pear fruit. However, the molecular basis for development of red skin is complicated and has not been well-understood thus far. ..."Starkrimson" (Pyrus communis L.), an introduced red pear cultivated in the north of China and its green mutant provides a desirable red/green pair for identification of candidate genes involved in color variation. Here, we sequenced and annotated the transcriptome for the red/green color mutant at three stages of development using Illumina RNA-seq technology. The total number of mapped reads ranged from 26 to 46 million in six libraries. About 70.11-71.95% of clean reads could be mapped to the reference genome. Compared with green colored fruit, a total of 2230 differentially expressed genes (DEGs) were identified in red fruit. Gene Ontology (GO) terms were defined for 4886 differential transcripts involved in 15 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Three DEGs were identified as candidate genes in the flavonoid pathway, LAR, ANR, and C3H. Tellingly, higher expression was found for genes encoding ANR and LAR in the green color mutant, promoting the proanthocyanidin (PA) pathway and leading to lower anthocyanin. MYB-binding cis-motifs were identified in the promoter region of LAR and ANR. Based on these findings, we speculate that the regulation of PA biosynthesis might be a key factor for this red/green color mutant. Besides the known MYB and MADS transcription families, two new families, AP2 and WRKY, were identified as having high correlation with anthocyanin biosynthesis in red skinned pear. In addition, qRT-PCR was used to confirm the transcriptome results for 17 DEGs, high correlation of gene expression, further proved that AP2 and WARK regulated the anthocyanin biosynthesis in red skinned "Starkrimson," and ANR and LAR promote PA biosynthesis and contribute to the green skinned variant. This study can serve as a valuable new resource laying a solid foundation for functional gene identification in the anthocyanin pathway of red-skinned pear and provide a good reference for relevant research on molecular mechanisms of color variation in other pear species.
Knowledge of fruit firmness in the distribution chain is essential for stakeholders, including producers, agri-food industries, and consumers. In recent years, there has been a general interest in ...predicting ripening-related firmness with non-destructive techniques. The objective of this study was to create a model, based on non-destructive methods that assess directly critical physiological parameters and quality attributes related to ripening, along with shelf-life time, to predict firmness of 'Rocha' pear (Pyrus communis L.), a protected designation of origin (PDO) commodity. Hereto, pear firmness profile was assessed for ten days at room temperature, after removal from different storage periods at cold conditions. Ripening was evaluated based on color alterations, ethylene production, and respiration rate. Pear firmness decreased drastically over time, concomitant with the yellowing of the fruit skin and increased ethylene production and respiration rate. These characteristics and shelf-life time were correlated with firmness by applying the Partial Least Squares (PLS) procedure to develop a mathematical model for predicting pear firmness during ripening. The model explained 89 % of the firmness variance during ripening and, after validation, showed high accuracy (R2 = 0.87). To the best of our knowledge, this is the first time that these physiological parameters, directly related to ripening-firmness, have been used to predict pear firmness using non-destructive measurements of the samples.
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•Firmness was correlated with ethylene, respiration, and color across shelf-life.•Firmness was predicted non-destructively using ethylene, respiration, and color.•A robust prediction model explaining 89% of firmness variation was developed.•The model was successfully validated with a different data set.
Core browning (CB) is a crucial physiological disorder that occurs in ‘Bartlett’ pears after excessive storage. Furthermore, environmental factors such as sunlight exposure cause serious related ...disorders during storage. 1-methylcyclopropene (1-MCP) positively delays the development of disorders, but results in poor eating quality at retail. Therefore, the primary purpose of this study was to evaluate whether sunlight exposure impacts the development of CB in ‘Bartlett’ pears and to develop optimal postharvest 1-MCP strategies for the pear industry to extend the fruit’s lifespan and deliver desirable eating quality to consumers that prefer melting texture. Over the course of a three-year evaluation, sunlight-exposed (SE) pears consistently displayed a higher CB index than the control and non-exposed (NE) pears after 150 d of regular-air (RA) storage at − 1.1 ± 0.5 °C plus 5 d at 20 ± 0.5 °C. The rapid development of CB was facilitated by decreases in ethylene production rate (EPR), peel chlorophyll content (PCC), and titratable acidity associated with increases in malondialdehyde and soluble o-quinones. Applying 0.15 and 0.3 μL L−1 1-MCP after 15 d of harvest completely protected the fruit from CB for up to 150 d of RA storage. However, these treated pears did not ripen. Lowering the 1-MCP concentration to 0.075 μL L−1 and postponing treatment to 60 d after harvest could control the CB index in the 1.53–2.33 range with a normal ripening process. For SE pears, the use of 0.15 μL L−1 1-MCP applied after 60 d of harvest reduced the CB index to 1.63 without impairing ripening capacity. It was difficult for the pear industry to monitor the EPR of 1-MCP-treated pears over the entire storage period. However, when the PCC of the treated pears fell to 0.4–0.5 IAD after 5 d of ripening, these pears could recover their ethylene generation capacity and softening behavior. Overall, the 0.15–0.075 μL L−1 1-MCP applied after 60 d of harvest provided great benefits in delaying CB development, improving storability, and retaining ripening capacity in SE ‘Bartlett’ pears following the prolonged RA storage.
•Sunlight induced a high core browning in ‘Bartlett’ pears after 150 d of storage.•MDA and soluble o-quinones contributed to the progress of sunlight-related CB.•0.15–0.075 μL L−1 1-MCP applied after 60 d of harvest reduced CB index.•Peel chlorophyll content could predict fruit softening and CB after treating 1-MCP.
ABSTRACT The objective of this study was to evaluate the influence of irrigation systems and water depths on physiological, biochemical and production processes of pear trees grown in the Brazilian ...semi-arid region. The experimental design was randomized blocks, with 2 × 4 factorial scheme, corresponding to two irrigation systems (drip and microsprinkler) and four irrigation depths (60, 80, 100 and 120% of the crop evapotranspiration - ETc), with four replicates. Water deficit and excess applied to plants are harmful to gas exchange as well as to biosynthesis and accumulation of carbohydrates, amino acids and proteins in leaves, compromising the cultivation cycle of pear plants grown in the Sub-Middle São Francisco region. The irrigation depth of 91.8% ETc promotes the highest production of pear (18.49 kg plant-1) under drip and microsprinkler irrigation systems, under the edaphoclimatic conditions of the Sub-Middle São Francisco region.
RESUMO O objetivo deste trabalho foi avaliar a influência de sistemas de irrigação e lâminas de irrigação sobre processos fisiológicos, bioquímicos e produtivos da pereira cultivada no Semiárido brasileiro. O delineamento experimental foi em blocos casualizados, com fatorial 2 x 4, sendo dois sistemas de irrigação (gotejamento e microaspersão) e quatro lâminas de irrigação (60; 80; 100 e 120% da evapotranspiração da cultura - ETc), com quatro repetições. A deficiência e o excesso hídrico aplicados às plantas são prejudiciais às trocas gasosas, bem como à biossíntese e acúmulo de carboidratos, aminoácidos e proteínas nas folhas, comprometendo o ciclo de cultivo de pereiras cultivadas na região do Submédio São Francisco. A lâmina de irrigação de 91,8% ETc promove a maior produção de pereira (18,49 kg planta-1) sob sistemas de irrigação por gotejamento e microaspersão, nas condições edafoclimáticas do Submédio São Francisco.
Currently, the main methods of virus elimination of fruit crops are dry-air thermotherapy, meristem culture and chemotherapy. The use of a complex of physical and chemical methods makes it possible ...to increase the efficiency of virus elimination. Improving the methods of recovery must be carried out in relation to certain types of viruses, the biological characteristics of the crop and variety. The purpose of the research is to study the effect of the Pharmaiod preparation on biometric, physiological parameters and the release of harmful viruses-free pear plants in the process of dry-air thermotherapy. Improvement of pear plants of varieties Letnyaya Zabava, Zolotoy Vityaz, hybrids R-11-9, R-10-3 and R-2-4 from harmful latent viruses of Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV), Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV) were carried out in 2020-2021 at the temperature of 38 °C for 3 months using a thermal chamber designed by the Federal Horticultural Research Centеr for Breeding, Agrotechnology and Nursery. Biometric parameters in pear plants depended on varietal characteristics, the duration of therapy and the concentration of the Pharmaiod preparation. In most of the varieties and forms studied, after 3 months of thermotherapy, the Pharmaiod preparation at a concentration of 1 ml/l contributed to an increase in the length of 1 shoot of pear plants by 1.4-3.1 times compared with the control. Under the conditions of a thermal chamber, according to a set of indicators, pear hybrids R-11-9 and R-10-3 were characterized by the highest heat resistance; medium heat resistance was shown by Letnyaya Zabava and Zolotoy Vityaz varieties; low – by R-2-4 hybrid. Higher heat-resistant varieties and forms were characterized by a more restrained growth of shoots in length compared to lower heat-resistant ones. An average negative significant correlation at the 5% significance level was established between the water content in the leaves and the length of 1 shoot (r = -0.52). The yield of virus-free pear plants depended on the type of virus. The yield of pear plants free from 4 major harmful viruses as a result of dry-air thermotherapy without the use of the Pharmaiod preparation was 50 %, with the use of the drug it was 60 %.
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•An itinerary for Rocha pears biofortification with calcium was developed in two orchards.•Monitoring of photoassimilates revealed only minor changes during Ca ...biofortification.•Accumulation indexes for calcium reached 47 %–63 % and 24 %–59 %.•Accumulation of Ca prevailed in the epidermis and central region of the fruits.•Physicochemical characteristics of fresh and heat-treated fruits did not vary substantially.
Low dietary intake of Ca in humans has been epidemiologically linked to various diseases, which can have serious health consequences over time. Accordingly, the development of an agronomic itinerary for Ca biofortification of Rocha pears and the assessment of physicochemical deviations prompted this study. Two orchards with contrasting soil and water characteristics were selected, characterized through orthophotomaping and, during fruits development, leaves were sprayed twice with Ca(NO3)2 (0.1, 0.3 and 0.6 kg ha−1) or CaCl2 (0.4, 0.8 and 1.6 kg ha−1), followed by pulverization only with CaCl2 (first once with 4 kg ha−1 and then four times with 8 kg ha−1). During fruits development net photosynthesis, stomatal conductance, transpiration rates, instantaneous and water use efficiency, only showed minor deviations, which indicated that the threshold of toxicity was not surpassed. Calcium contents varied during fruits development and at harvesting the average biofortification index varied between 47 %–63 % and 24 %–59 % in each of the orchards. Besides, the equatorial region of the fruits showed for all treatments (substantially in Ca treated samples) higher Ca contents in the epidermal and in the central regions. Fresh and heat-treated fruits (in a thermomix at 90 °C, during 10 min) biofortified with Ca only revealed minor differences and the sensory acceptability did not vary markedly. It is concluded that, although prevailing a heterogeneous distribution of Ca in fruit tissues, high indexes of biofortification in Rocha pears can be prompt in the orchards, without substantial physicochemical changes. Accordingly, agronomic biofortification with Ca can be used as a strategy for benefiting consumer’s health.
The flesh and peel of 19 pear cultivars (8 Tunisian dessert cultivars, 8 European dessert cultivars and 3 French perry pear cultivars) were studied for their phenolic composition. Phenolic compounds ...were identified by HPLC/ESI-MS2 and individually quantified by HPLC-DAD. Five classes of polyphenols were present: flavan-3-ols, phenolic acids, flavonols, anthocyanins and simple phenolics (hydroquinones). The total phenolic content ranged between 0.1g/kg Fresh Weight (FW) (‘Conference’ cultivar) and 8.6g/kg FW (‘Plant De Blanc’ cultivar) in the flesh and between 1.6g/kg FW (‘William vert’ cultivar) and 40.4g/kg FW (‘Arbi Chiheb’ cultivar) in the peel. Procyanidins, analyzed after thioacidolysis, were the main phenolic compounds in all pear cultivars either in the pulp or the peel, their constitutive units being essentially (−)-epicatechin. Tunisian dessert pears and French perry pears are richer in procyanidins with very high degree of polymerization (>100) for Tunisian pears. Peel procyanidins were less polymerized (from 4 to 20). Pear peel phenolic profile was more complex especially for Tunisian cultivars, with flavonols and in some cultivars anthocyanins.
•Polyphenol contents vary depending on pear fruit tissue and cultivar.•Polyphenol concentrations in pear peel are up to six times higher than in the flesh.•Procyanidins are the major phenolic compounds in pear flesh and peel.•Tunisian dessert pears contain very highly polymerized procyanidins (DPn>100).•Perry pears are richer on procyanidins with intermediate degree of polymerization.
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Here, the intensity and ratio of superoxide anion (O
2
•
), hydrogen peroxide (H
2
O
2
) and hydroxyl anion (OH
•-
) formation along the
in vitro
shootlets of four pear (
Pyrus communis
L.) ...rootstocks (i.e., Pyrodwarf, OH × F40, OH × F69 and OH × F333) were scrutinized under
E. amylovora
inoculation, over 144 hpi. Furthermore, following identifying the most tolerant and susceptible pear rootstocks (i.e., OH × F69 and OH × F40, respectively), the dynamic expression profiles of three ROS-scavenging enzymatic genes including superoxide dismutase (
SOD
), Catalase (
CAT
) and ascorbate peroxidase (
APX
) were elucidated in response to
E. amylovora
, over 96 hpi. The highest disease tolerance was observed in OH × F69, and OH × F333, Pyrodwarf and OH × F40 occupied the next descending positions, respectively. Furthermore, the O
2
•-
generation rates were almost similar in all the pears studied, though the accumulation of H
2
O
2
and OH
•-
and intensities thereof were considerably distinctive and significantly followed up the levels of disease resistance. Comparing to the controls (0 hpi), in both susceptible and tolerant pear rootstocks, transcription activity of
SOD
,
CAT
, and
APX
genes were overall stimulated with relatively high abundance over 24, 48, 72 and 96 hpi, though some fluctuations were also recorded. Our ROS results, altogether, indicated that
E. amylovora
is capable enough to stimulate ROS formation in pear, though its progress is extremely dependent upon the susceptibility ratio of the plant. Lastly, the particular expression patterns and different response time of three genes designated that pear rootstocks differentially activates genes encoding antioxidant enzymes to mitigate the possible damage of ROS during
E. amylovora
invasion.
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