Pyrus Communis Research Articles

Effects of species and varietal differences on intergeneric cross-compatibility between apple and pear

Hybridization across species and genus has been utilized to improve agriculturally important traits in crops. These interspecific and intergeneric hybridizations are often inhibited by reproductive barriers at the prezygotic and postzygotic stages. In this study, we used intergeneric hybridization between apple and pear to investigate the effects of species and varietal differences on pollen tube growth, seed germination, and seedling survival in a wide range of germplasms. In apple pistils pollinated by pears, inferior pollen tube growth was often observed for European pear cultivars, whereas hybrid seedlings derived from a cross between apple and European pear showed higher survival rate. In contrast, Japanese pear and Chinese pear pollination resulted in higher fruit setting which likely resulted from a higher rate of compatible pistils but a lower rate of seedling survival. Our results suggest the presence of both prezygotic and postzygotic barriers that occur independently in different crossing combinations. We also developed a Cleaved Amplified Polymorphic Sequence marker for detecting intergeneric hybrids derived from a wide range of crosses between apples and pears. The results of the present study will help in the development of intergeneric hybrids between apple and pear for introducing valuable traits from a diverse gene pool.

PbZAT12, Independent of PbMYB10, Activates Structural Genes to Promote Anthocyanin Biosynthesis in ‘Red Zaosu’ Pear Fruit (Pyrus bretschneideri Rehd.)

The red color of the pear peel in red-skinned European pear is due to the accumulation of anthocyanins. Numerous transcription factors play pivotal roles in anthocyanin biosynthesis, with zinc finger proteins frequently implicated in the regulation of this process via MYB10, as documented in earlier studies. In this article, we identified a zinc finger protein gene, named PbZAT12, that does not rely on PbMYB10, to regulate anthocyanin biosynthesis. The PbZAT12 protein was localized within the nucleus and exhibited a positive influence on the accumulation of anthocyanins in the peel of ‘Red Zaosu’ pears. Moreover, overexpression of PbZAT12 resulted in a significant up-regulation of PbDFR, PbANS, and PbUFGT expression levels in pear fruitlets. Y1H assays demonstrated a direct binding ability of PbZAT12 to proPbDFR, proPbANS, and proPbUFGT, which was supported by a dual luciferase assay, indicating its potential to activate the transcriptional activity of these promoters. However, in contrast to its effect on the aforementioned promoters, PbZAT12 did not exhibit an activation of PbMYB10. In summary, our findings suggest that a zinc finger transcription factor, PbZAT12, exerts a positive influence on anthocyanin biosynthesis in pear fruit through direct upregulation of the expression levels of PbDFR, PbANS, and PbUFGT.

The PcERF5 promotes anthocyanin biosynthesis in red-fleshed pear (Pyrus communis) through both activating and interacting with PcMYB transcription factors

As there is a strong interest in red-skinned pears, the molecular mechanism of anthocyanin regulation in red-skinned pears has been widely investigated; however, little is known about the molecular mechanism of anthocyanin regulation in red-fleshed pears due to limited availability of such germplasm, primarily found in European pears (Pyrus communis). In this study, based on transcriptomic analysis in red-fleshed and white-fleshed pears, we identified an ethylene response factor (ERF) from P. communis, PcERF5, of which expression level in fruit flesh was significantly correlated with anthocyanin content. We then verified the function of PcERF5 in regulating anthocyanin accumulation by genetic transformation in both pear skin and apple calli. PcERF5 regulated anthocyanin biosynthesis by different regulatory pathways. On the one hand, PcERF5 can activate the transcription of flavonoid biosynthetic genes (PcDFR, PcANS and PcUFGT) and two key transcription factors encoding genes PcMYB10 and PcMYB114. On the other hand, PcERF5 interacted with PcMYB10 to form the ERF5-MYB10 protein complex that enhanced the transcriptional activation of PcERF5 on its target genes. Our results suggested that PcERF5 functioned as a transcriptional activator in regulating anthocyanin biosynthesis, which provides new insights into the regulatory mechanism of anthocyanin biosynthesis. This new knowledge will provide guidance for molecular breeding of red-fleshed pear.

First Report of Fusarium avenaceum Causing Postharvest Decay of European Pear in Mid-Atlantic United States.

Fruit losses due to postharvest decay caused by several fungal species is a major challenge for pear production (Sardella et al. 2016). In December 2021, a European pear (Pyrus communis L.) 'Dawn' with brown, circular, watery, and sunken lesions was observed in cold storage at the USDA Appalachian Fruit Research Station in Kearneysville, West Virginia. Only 1 of 14 'Dawn' pears examined in cold storage had the described disease symptoms. The fruit was surface sterilized, and symptomatic tissue was transferred to potato dextrose agar (PDA) and incubated at 25°C under continuous light. The isolate was hyphal tip purified and propagated on PDA plates at 25°C. The colonies grew an average of 8 mm/day and produced fluffy white aerial mycelium and pigmented rings of golden yellow which then darkened to pink with a dark pink on the reverse. The isolate was also cultured in liquid basal medium with carboxymethyl cellulose (Moura et al. 2020) for 7 days at 25°C to promote macroconidia formation. Macroconidia were slightly falcate with a tapering apical cell, usually 2 to 4 septate, and on average 16.8 µm long by 2.8 µm wide. The isolate was identified as Fusarium spp. based on morphology. Identity of the isolate was confirmed through sequencing of the ITS and TEF1 gene region (Stielow et al. 2015). The ITS and TEF1 sequences were deposited in GenBank (OP007197 and OP007198). BLAST analysis of the ITS amplicon identified multiple Fusarium spp. with 100% identity and 100% query coverage including F. avenaceum KJ562378. BLAST analysis of the TEF1 amplicon showed 99% identity and 99-100% query coverage with F. avenaceum isolates KM189442 and MK512754. Organic Bartlett pears were surface sanitized with a 1% aqueous chlorine solution, rinsed with sterile water and dried in a laminar flow hood. Fruit were then wounded with a sterile nail (4 mm diameter x 4 mm depth) and inoculated with a 4 mm mycelial plug taken from a 7- to 10-day old culture on PDA and wrapped with Parafilm. Plugs taken from sterile PDA were used as a control. Inoculated fruit were stored at 25°C in fruit trays in plastic bins for 7 days. Six fruit composed a replicate, and the experiment was repeated for a total of two replications. Lesions developed within 48 hours and expanded to an average of 28.5 mm by day 7. No lesions were observed on control fruit. Symptoms observed on inoculated pears were the same as the decay observed on the original pear obtained from cold storage. Fungal colonies isolated from the lesions and cultured on PDA morphologically resembled the original isolate from the infected pear. In 2014, F. avenaceum was first reported in the United States to cause post-harvest decay of apples in Pennsylvania (Kou et al. 2014). In the Netherlands, F. avenaceum has been reported to cause postharvest decay of 'Conference' pears but was observed at low frequencies (1-5%) in packing-house surveys (Wenneker et al. 2016). Fusarium spp. was also recently found on European pears in Southern Oregon (KC and Rasmussen 2020). F. avenaceum can produce mycotoxins which is a concern for fruit processing (Munkvold et al. 2021). Monitoring for this pathogen to prevent losses and mycotoxin contamination of processed fruit products will be import for consumer safety. To our knowledge, this is the first report of F. avenaceum causing postharvest decay of European pear in the Mid-Atlantic region of the United States.

Pest categorisation of Euzophera semifuneralis.

The EFSA Panel on Plant Health performed a pest categorisation of Euzophera semifuneralis (Lepidoptera: Pyralidae), the American plum borer for the EU. This insect is native to North America, reported from the United States, Canada and Mexico. Out of its native range it is only present in Türkiye. It has not been reported in the EU and is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It can complete from one up to three generations per year in its native range and is polyphagous, feeding on 22 genera in 16 plant families. Host plant species commonly found in the EU include black walnut (Juglans nigra), mulberry (Morus alba, M. nigra), olive (Olea europaea), almond (Prunus dulcis), apricot (P. armeniaca), peach (P. persica), plum (P. domestica), sweet cherry (P. avium), apple (Malus domestica), pear (Pyrus communis) and pomegranate (Punica granatum). E. semifuneralis is generally known as pest of trees affected by mechanical injuries, frost or canker diseases. The pest is also known to vector the fungus Ceratocystis fimbriata which is not known to occur in the EU. Climatic conditions and availability of host plants in some EU countries would allow this species to establish and spread. Impact in cultivated hosts including apples, plums, mulberries, almond, olive and ornamental broadleaf trees is anticipated. Phytosanitary measures are available to reduce the likelihood of entry and spread. E. semifuneralis meets the criteria that are within the remit of EFSA to assess for this species to be regarded as a potential Union quarantine pest.

Genetic mapping of the pear scab resistance gene Vnlf using a pseudo-BC3 population derived from Japanese pear cultivars and European pear ‘La France’

Pear scab disease caused by Venturia nashicola is one of the most serious diseases of Asian pears. To facilitate the breeding of scab-resistant cultivars, we mapped and developed markers for a resistance gene from the European pear (Pyrus communis) cultivar ‘La France’. By using a pseudo-backcross strategy to introduce genes from ‘La France’ into Japanese pear (P. pyrifolia) cultivars, we developed a mapping population from a cross between Japanese pear ‘Akiakari’ and interspecific hybrid progeny line 537–14. The individuals in the mapping population were evaluated for resistance by inoculation testing in 2020 and 2021. The segregation ratio of resistant to susceptible individuals was 1:1, indicating that resistance is inherited as a single dominant gene, which we named Vnlf. A genetic linkage map was constructed using single-nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers. On the basis of the genetic map of 537–14, we narrowed down the putative region carrying Vnlf to 959 kb on chromosome 2 between SNPs Chr2_20220913 and Chr2_21180341. To facilitate marker-assisted selection in Japanese pear breeding programs, we developed SSRs closely linked to Vnlf, one of which (LFA02a09) showed complete linkage to the resistance phenotype in an inoculation test of 175 individuals. These linked markers will enable introgression of Vnlf into breeding materials without the need for inoculation tests and will facilitate pyramiding Vnlf with other scab resistance loci.

Stionic interaction on leaf parameters and survival of grafted pear saplings

The present study was conducted to find the effect of different rootstock-scion combinations on multiplication of Pear (Pyrus communis) saplings. There were four scion cultivars and five rootstocks, constituting twenty treatment combinations. Data revealed that maximum leaf length and width were recorded in cv. Chinese Sandy Pear grafted on BA-29 and Pear sucker rootstocks. However, the minimum leaf length and width were recorded in cv. Carmen grafted on Quince and cv. Abate Fetel on BA-29 rootstocks. The highest leaf area (23.46 cm2) was recorded in cv. Chinese Sandy Pear on BA-29, while it was minimum (14.19 cm2) in cv. Abate Fetel on BA-29. Leaf chlorophyll content was highest (3.71 mg/g) in Chinese Sandy Pear grafted on Quince. Length (27.11 μm) and width (9.96 μm) of stomata were recorded maximum in cv. Abate Fetel grafted on Kainth and cv. William Bartlett grafted on Quince, respectively. In contrast, the stomatal density was maximum (20.63/μm2) in cv. Carmen grafted on Quince. Grafted saplings of cv. Abate Fetel on Quince , cv. Chinese Sandy Pear on BA 29 and cv. William Bartlett on Quince C rootstocks recorded 86.67 per cent survival compared to other grafts. More number of saleable plants was recorded when cv. William Bartlett was grafted on Quince (86.33%). The investigations concluded that pear varieties raised on Quince rootstock had higher values for all studied parameters, followed by Quince C rootstock.

Porosity quantification in pear fruit with X-ray CT and spatially resolved spectroscopy

Hypoxia-related disorders in apple and pears such as browning have been associated with insufficient transport of respiratory gasses inside the fruit during controlled atmosphere (CA) storage. Tissue porosity affects gas exchange and, hence, fruit respiration. It might, therefore, be interesting to adapt the storage conditions to the porosity of the fruit, especially in the case of low-porosity fruit like pears, which are highly susceptible to browning disorders. To improve the current CA storage strategies in that direction, fast, non-destructive measurement of fruit porosity is required. To this end, X-ray CT-based porosity maps and spatially resolved spectroscopy (SRS) were used to characterize respectively the porosity and optical properties of intact pear cultivars (Pyrus communis L.), including ‘Thimo’, ‘Cepuna’, and ‘Conference’. Thereafter, the link between the fruit porosity and light-scattering properties was investigated. The porosity of the tissue region from the fruit surface down to 3 mm deep as well as the spatially averaged porosity of intact pears from 3 cultivars were found to be linearly correlated to the reduced scattering coefficient (µs’) at 760 nm and 835 nm calculated from SRS measurements. Both ‘Cepuna’ and ‘Conference’ pears showed similar porosities and scattering levels, which were slightly higher than those observed for ‘Thimo’ pears. The presented results suggest the possible application of laser scatter imaging at 760 nm and 835 nm for fast, contactless and non-destructive assessment of pear porosity.

Lipid -Lowering Effect of Polysaccharide (Pectin) of Viscum album L. Plant in Rats

Disturbances of lipid metabolism is a predisposing factor of cardiovascular diseases, which are accompanied by high mortality rates of the population - ischemic heart disease and ischemic stroke. Plant polysaccharides can be promising remedies for correction of lipid imbalance.
 In this regard, the aim of the study was to assess the hypolipidemic activity of polysaccharides isolated from the leaves of mistletoe.
 The test-object was the leaves of the white mistletoe (Viscum album L.) growing on the apple (Malus domestica Borkh.), and the pear (Pyrus communis L.). Polysaccharides (water-soluble polysaccharides and pectin substances) were quantitatively determined by the gravimetric method followed by reprecipitation from ethanol. The qualitative composition was evaluated by thin layer chromatography. Functional groups in polysaccharides were determined by titrimetric method. The hypolipidemic activity of the obtained polysaccharides was determined under oral administration at a dose of 100 mg / kg in Wistar rats by the change of the concentration of total cholesterol, triglycerides, LDL and HDL cholesterol. The change of the content of cholesteryl ester transfer protein and Niemann-Pick C1-Like1 protein was also determined.
 As a result, it was found that among the polysaccharides in the leaves of mistletoe, pectin substances are predominate, which belong to the group of low-esterified pectins. A significant content of free carboxyl groups in pectins from the leaves of mistletoe was also found. The study of hypolipidemic activity showed that, among the polysaccharides of mistletoe leaves, pectin substances exert a more pronounced effect on lipid metabolism, the use of which reduced the content of triglycerides, total cholesterol and LDL cholesterol with an increase in LDL cholesterol in rats, probably due to a decrease in the activity of cholesteryl ester transfer protein and Niemann-Pick C1-Like1 protein. At the same time, at the level of the trend, mistletoe pectins showed a higher level of activity than analogous compounds obtained from the leaves of host-plants. It should be noted that the severity of the pharmacological effect of mistletoe pectins did not depend on the host-plants.
 Thus, based on the obtained results, it can be assumed that pectins obtained from the mistletoe leaves can be a potentially effective and safety hypolipidemic agent.

Combining thermal imaging and soil water content sensors to assess tree water status in pear trees.

Volumetric soil water content is commonly used for irrigation management in fruit trees. By integrating direct information on tree water status into measurements of soil water content, we can improve detection of water stress and irrigation scheduling. Thermal-based indicators can be an alternative to traditional measurements of midday stem water potential and stomatal conductance for irrigation management of pear trees (Pyrus communis L.). These indicators are easy, quick, and cost-effective. The soil and tree water status of two cultivars of pear trees 'D'Anjou' and 'Bartlett' submitted to regulated deficit irrigation was measured regularly in a pear orchard in Rock Island, WA (USA) for two seasons, 2021 and 2022. These assessments were compared to the canopy temperature (Tc), the difference between the canopy and air temperature (Tc-Ta) and the crop water stress index (CWSI). Trees under deficit irrigation had lower midday stem water potential and stomatal conductance but higher Tc, Tc-Ta, and CWSI. Tc was not a robust method to assess tree water status since it was strongly related to air temperature (R = 0.99). However, Tc-Ta and CWSI were greater than 0°C or 0.5, respectively, and were less dependent on the environmental conditions when trees were under water deficits (midday stem water potential values< -1.2 MPa). Moreover, values of Tc-Ta = 2°C and CWSI = 0.8 occurred when midday stem water potential was close to -1.5 MPa and stomatal conductance was lower than 200 mmol m-2s-1. Soil water content (SWC) was the first indicator in detecting the deficit irrigation applied, however, it was not as strongly related to the tree water status as the thermal-based indicators. Thus, the relation between the indicators studied with the stem water potential followed the order: CWSI > Tc-Ta > SWC = Tc. A multiple regression analysis is proposed that combines both soil water content and thermal-based indices to overcome limitations of individual use of each indicator.

Fruit Characteristics of Transgenic pear (Pyrus communis L.) Trees During Long-Term Field Trials.

The quality of transgenic fruits was studied only for apple, plum and citrus. We first evaluated the transgenic fruit characteristics of pear, which is one of the most consumed fruit crops. The size, shape and biochemical composition of fruits from field-grown pear trees with marker genes were analyzed for 5 years. Soluble solids, vitamin C, and phenolic compounds varied significantly between transgenic lines, but these deviations were inconsistent. Arbutin content and sugar:acidity ratio were the most stable parameters. One transgenic line showed a stable increase in fruit weight (by 12.2-21.2%). The extremely dry and hot season increased the total phenolics (2.6-3.6 times) and tannin (3.2-3.6 times) levels, but not flavonoids. The harvest year had a stronger effect on analyzed fruit parameters than the genotype. Our study found no unintended effects of genetic transformation on pear fruit quality and confirms the importance of long-term field tests for perennial transgenic plants.

Application of phyto-fabricated zinc oxide nanoparticles to diminish brown spot of pear whilst maintaining its quality.

Pyrus communis is a common fruit of temperate region, its domestication and origin is at two different points, Asia and China. Pear fruits bearing brown spot symptoms were picked, and pathogen was isolated and poured on Potato Dextrose Agar (PDA) media. On basis of molecular and molecular analyses, this isolated pathogen was identified as Alternaria alternata. Zinc oxide nanoparticles (ZnO NPs) were prepared from Theveti peruviana leaf extract and were characterized through various techniques Fourier Transform Infrared Spectroscopy (FTIR) analysis of prepared ZnO NPs depicted the presence of agents responsible for stabilization and reduction such as alkenes, alkynes, nitro compounds, alkyl halides, aromatic compounds and aliphatic amines. X-ray diffraction (XRD) analysis confirmed the size (27 nm) and crystalline nature of ZnO NPs. Scanning electron microscopy (SEM) depicted the irregular shape of the prepared ZnO NPs. Mass percentage of zinc (79.84%) and oxygen (20.16%) was depicted using Energy Dispersive X-Ray (EDX) analysis. The in vitro and in vivo antifungal activity (A.F) of prepared NPs against A. alternata was confirmed by poisoned food technique and wound inoculation method. On the basis of which it was concluded that 1.0 mg/mL concentration of ZnO NPs could effectively inhibit A. alteranata growth and minimize the risk of brown spot of pear. SEM images of A. alternata under 1 mg/mL NPs showed the deformation in morphology of A. alternata. ZnO NPs also aided in the preservation of its various organoleptic and biochemical properties. The high percentage of soluble solids, firmness, ascorbic acid and sugars demonstrated its high quality. It has been concluded that 1 mg/mL ZnO NPs can effectively control brown spot of pear while maintaining its quality. In addition, the method might be applied to control emerging diseases in an ecofriendly way to meet the global food demand. RESEARCH HIGHLIGHTS: Isolation and characterization of pathogen causing brown spot in pear. Pathogenicity of A. alternata was checked on healthy fruits. Thevetia peruviana leaf extract was used for the synthesis, characterization and antifungal assay of ZnO Nanoparticles. Green synthesized nanoparticles can be economically effective alternative fungicide for the large scale in agriculture fields.

Genome-wide identification and characterization of the PbrATG family in Pyrus bretschneideri and functional analysis of PbrATG1a in response to Botryosphaeria dothidea

The pear is an economic fruit that is widely planted around the world and is loved by people for its rich nutritional value. Autophagy is a self-protection mechanism in eukaryotes, and its occurrence often accompanied by the degradation of damaged substances in cells and the recycling of nutrients. Autophagy is one of the mechanisms through which plants respond to environmental stress and plays an important role in plant development and stress resistance. Functional studies of autophagy-related genes (ATGs) have been performed on a variety of plant species, but little information is available on the ATG family in pear (Pyrus bretschneideri Rehd). Therefore, we analyzed the evolutionary dynamics and performed a genome-wide characterization of the PbrATG gene family. A total of 28 PbrATG members were identified. Phylogenetic analysis showed that PbrATGs were more closely related to ATGs of European pear and apple. Evolutionary analysis revealed that whole-genome duplication (WGD) and dispersed duplication events were the main driving forces of PbrATG family expansion. Expression analysis of different pear tissues showed that all the genes were expressed in different pear tissues, and different PbrATGs are expressed at different times and in different locations. Moreover, all PbrATGs also responded to different abiotic stresses, especially salt and drought stress, which elicited the highest expression levels. Pear seedlings were subsequently infected with Botryosphaeria dothidea (B. dothidea). The results showed that different PbrATGs had different expression patterns at different infection stages. According to the gene expression data, PbrATG1a was selected as a key autophagy gene for further analysis. Silencing of PbrATG1a reduced the resistance of pear to B. dothidea, which resulted in increased lesions, reactive oxygen species (ROS) contents, antioxidant enzyme activity, and gene expression levels in the silenced pear seedlings after B. dothidea inoculation. In this study, a comprehensive bioinformatic analysis of ATGs was conducted, and the functions of PbrATGs in pear development and in response to stress were elucidated, which laid a foundation for further study of the molecular mechanism of autophagy and a new strategy for pear resistance breeding.

Identification of effective plant extracts against candidiasis: an in silico and in vitro approach

BackgroundGlobally, millions of people suffer from repeated fungal infections affecting the skin, keratinized tissues, and mucosal membranes. Approximately 1.7 million cases result in death with an elevated incidence rate among immunocompromised people that may later result in severe infections. Among the causative agents, Candida albicans are the most prevalent fungi inducing subcutaneous to invasive candidiasis. Although they are commensals in human body alteration in gut or prolonged treatments results in candidiasis. Several virulence proteins of C. albicans are involved in infections and secreted aspartic proteases2 (SAP2) plays an important role among them by causing damage to the reconstituted human epithelium. In the present study, phytochemicals from Heliotropium indicum, Grona triflora, Ziziphus mauritiana, Atalantia racemosa, Coccinia grandis, Caryota urens, Aristolochia bracteolata, Evolvulus alsinoides, Pyrus communis and Commelina benghalensis were studied against SAP2 with the help of bioinformatic tools to understand their binding efficiency.ResultsThe phytochemical structures were retrieved from PubChem database and the target protein structure was retrieved from PDB database with ID:3PVK. ADME profiling for phytochemicals was performed with Qikprop module, followed by docking with protein using Schrodinger software. Docking studies showed that Indicine-N-Oxide from H. indicum scored the significant glide score of − 5.54 kcal/mol. Finally, antifungal studies against C. albicans were conducted using several extracts of plants containing phytochemicals with considerable glide scores on docking studies. The Ethyl acetate leaf extract of H. indicum prominently inhibited the fungal growth when compared with the control.ConclusionIdentification of effective therapeutic candidates for the treatment of fungal infection is facilitated by the potential of H. indicum to hinder fungal growth and the interaction of their phytocompounds with fungal targets paves a way for developing a novel drug.

Low temperatures inhibit the pectin degradation of ‘Docteur Jules Guyot’ pear (Pyrus communis L.)

The most remarkable characteristic of European pears is extremely perishable and difficult to store after postharvest softening. Low-temperature storage is one of the most commonly used methods to prolong the shelf life of European pears. However, the regulatory mechanism of the low-temperature delay of the softening of European pears is still unclear. In this study, the fruit firmness, pectin polysaccharide content, pectin-degrading enzyme activity, and pectin degradation gene expression of ‘Docteur Jules Guyot’ pears under low temperature (LT) and room temperature (RT) were analyzed. It was found that water-soluble pectin (WSP) was significantly negatively correlated with fruit flesh firmness, and the activities of several pectin-degrading enzymes were inhibited under LT storage conditions. In addition, it was also found that the gene expression patterns of PcPME2, PcPME3, PcPG1, PcPG2, PcPL, PcGAL1, PcGAL2, PcGAL4, and PcARF1 were inhibited by LT. The C-repeat binding factors PcCBF1 and PcCBF2 were also inhibited by long-term LT storage. Correlation analysis showed that the expression of PcCBFs was positively correlated with pectin-degradation enzyme genes, and we found that the promoters of many pectin-degradation enzyme genes contain the CRT/DRE motif, which CBF can directly bind. Therefore, it is speculated that long-term low-temperature conditions inhibit pectin degradation through PcCBFs.

Evaluation of reflective groundcovers for pest and fruit quality management in commercial pear orchards

AbstractReflective groundcovers can improve crop yield and quality and deter pests by increasing light penetration into plant canopies. In pear (Pyrus communis L.) orchards, this could increase profitability and reduce reliance on insecticides to manage pear psylla (Cacopsylla pyricola [Foerster]). Two types of reflective groundcovers, metallized polyethylene film (metallized film) and white geotextile fabric (reflective fabric), are known to increase pear yield and quality, and metallized film was recently reported to suppress pear psylla. Here, we tested reflective fabric for pear psylla suppression at a research orchard in 2019, then we partnered with five pear orchard managers to test metallized film and reflective fabric for pear psylla suppression at five conventional commercial orchards in 2020 and one organic commercial orchard in 2021. There was evidence of pear psylla suppression by both metallized film and reflective fabric, but effects varied among reflective materials, pear psylla life stages, season and year of study. Reflective groundcovers did not affect fruit size, weight, sunburn or pest mite abundance, and they were compatible with pear psylla biocontrol. Low perceived benefit relative to cost was a barrier to continued trialling and adoption. Whereas orchardists in our study used reflective groundcovers in addition to normal pesticide regimes, previous research studies suggest that reflective groundcovers can profitably replace some insecticides. Future studies are needed to test the outcomes of replacing pesticides with reflective groundcovers in commercial orchards and understand under what circumstances they improve pear quality and yield.

Effect of solar radiation on pigmentation, phenolic content and antioxidant activity in ‘Forelle’ pears during fruit growth and ripening

ABSTRACT Blush development is an important commercial quality attribute in European pear, but some cultivars exhibit reduced red colouration at harvest due to environmental stress. The objective of this study was to evaluate the effects of bagging ‘Forelle’ pear fruit at 85, 57 and 27 d before commercial harvest on ripening, pigment concentration, phenolic content and antioxidant activity, with unbagged fruit (0 d) considered a control treatment. It was found that bagging reduced the fruit colouration and concentration of pigments, particularly anthocyanins and carotenoids, as well as the phenolic and antioxidant contents, but did not affect fruit ripening. During fruit growth, the anthocyanin concentration of fruit in the control treatment peaked at 57 d before harvest and then decreased at 27 d before harvest, but at the time of harvest, both this variable and blush development were higher in unbagged fruit than in bagged fruit, particularly where longer periods of bagging had been used. These results indicate that reducing radiation stress through continuous bagging of the fruit does not improve the colour intensity of ‘Forelle’ pears at harvest, and the 27 d prior to harvest appear to be most important for blush development.

Evaluation of Different Elite Pear (Pyrus communis L.) Varieties for North Western Plain Zone of Uttar Pradesh, India

The present investigation was carried out at Horticultural Research Centre under Sardar Vallabhbhai Patel University of Agriculture and Technology Meerut, during 2019-2020 and 2020-2021 seasons to select the promising varieties of pear. The experiment was conducted on a 7-8-year-old pear orchard spaced at a distance of 3 m × 4 m. On four varieties i.e. Baggugosa, Punjab Beauty, Punjab Gold and Punjab Nectar and each replicated thrice. Each treatment consisted of three trees with a total of 12 trees. The obtained results showed that the highest canopy spread (3.765 m), number of fruits per plant (57.995) and fruit yield per plant (6.235 kg) were found to be significant. On the other side, number of flowers per plant (98.98), number of primary branches (6.165), stem girth (31.83 cm), plant height (6.965 m), fruit weight (5 fruits) (122.45 g), fruit length (73.97 mm) and fruit width (58.505 mm) were found to be non-significant. The results of the present study indicate that on the basis of their flowering times, full bloom times and morpho-economic characteristics, Punjab Nectar appeared to be a superior variety in terms of tree morphology and others as moderate. Further, it can be concluded that the variety Punjab Beauty had more productivity and the fruits of Punjab Nectar and Punjab beauty were having more marketable fruit traits.

Physiological disorders, textural property, and cell wall metabolism of ‘Gem’ pears (Pyrus communis L.) affected by oxygen regimes and harvest maturity under controlled atmosphere storage

The primary purpose of this study was to develop optimal controlled atmosphere (CA) strategies for the pear industry to utilize ‘Gem’ pears. The influences of two O2 regimes (1.0% O2 and 2.2% O2 [commercial practice concentration] with ∼0.05% CO2) on decay, physiological disorders (i.e. internal breakdown, superficial scald, and black speck), storage and eating quality attributes, cell wall components, and cell wall-modifying enzymes were evaluated at two harvest maturities (H1; 48.01 N; H2; 42.19 N) of ‘Gem’ pears. Earlier harvested pears (H1) stored under regular-air (RA) conditions had lower rates of superficial scald and internal breakdown relative to later harvested pears (H2), especially in extended storage (8–10 months). However, storage and eating quality for air-stored H1 and H2 fruit deteriorated after 6 months. CA regimes extended ‘Gem’ storage longevity from 8 to 10 months, with 1.0% O2 resulting in lower incidences of superficial scald and internal breakdown disorders and higher peel chlorophyll content and titratable acidity by delaying the peak of ethylene production rate (EPR) compared to 2.2% O2. Notably, the rates of black speck in H1 and H2 fruit were controlled at below 5% in both O2 regimes. Furthermore, 1.0 and 2.2% O2 stored H1 and H2 pears ripened and developed a melting texture with full flavor and juiciness during 6–8 months of storage. Additionally, the water-soluble (WSP), cyclohexanetrans-1,2-diaminetetra-soluble (CSP), and Na2CO3-soluble polyuronides (SSP) combined with pectin methylesterase (PME), α-arabinofuranosidase (α-ARF), and β-galactosidase (β-GAL) contributed to fruit softening and desirable eating quality in ‘Gem’ pears. In conclusion, 2.2% O2 with ∼0.05% CO2 improved the fruit quality of ‘Gem’ pears harvested at 48.01 N, while the quality of fruit harvested at 42.19 N or below could be improved by the application of 1.0% O2.

Impact of Quince Clonal Rootstocks on Yield and Fruit Quality Characteristics of European Pear (Pyrus communis L.) Cultivars

Impact of Quince Clonal Rootstocks on Yield and Fruit Quality Characteristics of European Pear (Pyrus communis L.) Cultivars