Pear

Prickly pear cactus (Opuntia ficus indica), is a Cactaceae plant with a great economic relevance in the world. Nowadays, nopal cactus industry is active and rapidly expanding.In fact, the seeds oil sector is the best exploitation due to the high price of this oil. Moisture content, oxidative stability, quality index, total phenol, flavonoids, chlorophyll and carotenoid contentof prickly pear seed oil were analyzed.The seeds used in this study were provided by a cooperative DAR ATABIAA located in Chouihia (Eastern region of Morocco) during the harvesting season 2020. The samples were obtained from wild trees grown in this region. Results showed that moisture content of prickly pear seeds was 9.12%, whereas the acidity and peroxide index value was 1.11% and 4.44 meq O2/kg respectively, andan oxidative stabilityof 17.31 hours. The total phenolic and the flavonoid content values for theseseed oilsare 260.07 mg/kg and 65.99 mg/kg, respectively. Furthermore, the results show a carotenoid ...

The effects of gamma irradiation on lesion diameters of grey mold disease of pear and some physico-chemical parameters of pear fruits were studied in this investigation as a prestorage treatment for extend shelf life of pear fruits. Pear fruits (Pyrus Communis, L.) were exposed to different gamma irradiation doses 0, 0.5, 1, 1.5, 2, 2.5 and 3 KGy and stored for 10, 20 and 30 days in 0C and 85-90% RH. The increment of irradiant dose caused decrement of lesion diameters of grey mold disease of pear. The narrowest diameters were recorded with 3.0 KGy irradiation dose. The low dose of gamma irradiation 0.5 KGy gave a relatively high value of firmness although in higher doses firmness of pear fruits decreased. The highest loss weight was found in unirradiated fruits while the loss of weight in all irradiated fruits was still lower than those of unirradiated ones and low radiation doses decreased the loss of weight. Total soluble solid increased with increasing in storage periods with respect to gamma irradiation effect there was fluctuation in total soluble solid values. There was a decreasing in acidity during storage of irradiated and un-irradiated fruits. Free amino acid and soluble protein show a slight increasing at 0.5 KGy such increasing was followed by a gradual decrease in higher gamma irradiation doses.

Pear fire blight bacterial disease caused by Erwinia amylovora as biotic stress is one of the most serious diseases that cause great loss of pear crop in Egypt and over world. E. amylovora pathogen was isolated from pear infected plants and molecularly characterized by PCR using specific primer. Koch's postulates applied to assure the pear fire blight disease that causes high defects in the trees growth and yield. The treatments which used in this research to control the disease were Bacillus subtilis as abio-agent, Huwa San 25 commercial product of hydrogen peroxide (H 2 O 2), oxolinic acid (Starner 20%) and antibiotic streptomycin. In vitro bio-agent such as Bacillus subtilis was able to inhibit the bacterial growth of E. amylovora. However , H 2 O 2 did not inhibit the bacterial growth as compared to the starner and streptomycin which showed significant inhibition. Under greenhouse disease symptoms and severity of inoculated pear seedlings and treated with B. subtilis, H 2 O 2 , starner and streptomycin showed significant inhibition and decrease as compared with the control infected only. Under field conditions and natural infection, as a result of application with B. subtilis, H 2 O 2 , starner and streptomycin, disease severity, disease symptoms and electrolyte leakage % were decreased significantly. Interestingly that the vegetative growth such as shoot length and diameter were significantly increased with all treatments. Fruit set, yield and quality were improved compared to the control. At the open field, the application of H 2 O 2 gave the best results for the most characteristics followed by Bacillus subtilis, starner and strepto-mycin respectively.

Pear as a fruit species has a special place because of its quality characteristic. The fact that about 20,000 pear seedlings are considered to be sold annually in Bosnia and Herzegovina, which are autochthonous or spontaneously expanded varieties, also speaks in favor. The main goal of this research is to analyze the genetic variability of nine autochthonous pear varieties in Tuzla Canton, Bosnia and Herzegovina to enable the conservation and expansion of existing genetic resources. The study included nine autochthonous pear varieties. Samples of young leaves were collected on the following localities: the town of Srebrenik, the town of Gradačac, the municipality of Čelić-Tuzla Canton, Bosnia and Herzegovina, in the spring 2019. To determine genetic diversity, 12 SSR (Simple Sequence Repeats) markers were genotyped. There were no cases of synonyms or homonyms in the analyzed set. Each of the nine tested varieties represents a unique genotype. Autochthonous pear cultivars analyzed in...

This study was conducted to evaluate the effect of associated consortium fungal species on the natural fermentation of the mesocarp of Pyrus communis (Pear). The combined role played by the fungi (moulds and yeasts) involve in the natural fermentation of the Pear mesocarp were also investigated. Fresh and ripe pears were washed and surface sterilized with ethanol. The mesocarp was then scraped into a bowl and covered with a net to allow the action of aerobic fermentation for 50 days. Fungi were isolated from the samples at interval of 5 days. The morphological, microscopic and biochemical characteristics as well as the fungal count were also carried out according to standard methods. The physicochemical parameters of the pear’s mesocarp such as pH, total titrable acidity (TTA), moisture contents and total reducing sugar were also determined at every 5 days according to standard methods. The results showed that there were eight strains of mould namely: Aspergillus niger, Aspergillus ...

Background and purpose: Medicinal plants including the prickly pear cactus have been reported to modulate blood sugar levels. Extracts of prickly pear cactus have been used in various parts of the world to manage diabetes mellitus. However the cactus is viewed as a weed in Kenya. The current study therefore aimed at evaluating the efficacy of prickly pear cactus cladode extracts from Kenya in managing diabetes mellitus in induced mice. Methods: Healthy, adult Swiss white albino male mice weighing 20-30g were induced with diabetes mellitus using Alloxan (150 mg/kg body weight) administered intra-peritoneally. Prickly pear cactus cladode extracts were administered at daily dosage of 0.6 ml for pre-determined periods. Fasting blood sugar levels and live body weights were monitored at intervals of 72 hours throughout the experimental period of 30 days. Results: Alloxan administration resulted in about 3- to 4-fold increase in blood sugar levels. Treatment of diabetic mice with cactus cl...

ABSTRACT This research was conducted to evaluate and compare responses to Erwinia amylovora infection by two host species, apple (Malus  domestica Borkh.) and pear (Pyrus communis L.), activated by salicylic acid (SA). Apple rootstocks, ‘MM-111’ (tolerant) and ‘MM-106’ (susceptible), and pear cultivars, ‘Harrow Sweet’ (tolerant) and ‘Spadona’ (susceptible) were inoculated under in vitro conditions from basal parts with E. amylovora Ea273. The pathogen activity was traced by adding bromocresol green, and evaluating the pH variation in the media; measuring necrosis progression rate and counting the number of necrosed internodes in a 240 h period. SA treatments on the in vitro shootlets were categorized by concentration (0.05, 0.1, 0.5, 1, 2, 5, 10 and 0 mg/L as control) and days of shootlets exposure to SA before infection (1, 3, 5, 7 days and 0, as control). SA did not cause similar effects on disease progress in the two tested species. SA failed to reduce symptom progression in apple rootstocks and increased pathogenicity of bacteria. In pear, SA presence in all treatments successfully decreased symptom progression rate in both cultivars. Longer exposure of pear shoots to SA resulted in more effective disease control. In both species, symptoms progression rates significantly corresponded to the pattern and severity of H2O2 generation in host tissues. It appears that apple and pear respond differently to the SAR activation by SA. These dissimilar responses of hosts could be derived from contrasting behavior of reactive oxygen radical scavenging enzymes in the two species.

The storage life of ‘Alexander Lucas’ pear is limited by the occurrence of internal storage disorders during controlled atmosphere (CA). 1-Methylcyclopropene (1-MCP) can be used to delay pear ripening, however, its interaction with CA conditions is not well understood. ‘Alexander Lucas’ fruit were treated with 1-MCP at 300 nL L-1 for 24 h in air at-0.5 or 1.0 °C before being stored. Fruit were kept at-0.5 or 1.0 °C in normal air or CA (2.0 kPa O2 plus <0.7 kPa CO2). After six months of storage, superficial scald did not develop in fruit. The highest incidence of flesh browning (72.2 %) was found in air-stored fruit at-0.5 °C without 1-MCP treatment. Storage in air at 1.0 °C plus 300 nL L-1 1-MCP produced 88.8 % of healthy fruit. In contrast, 1-MCP increased the incidence of flesh and core browning under CA conditions. 1-MCP and CA maintained greener skin color and higher titratable acidity. No significant differences were found for fruit firmness, total soluble solids and ascorbi...

A new spontaneous mutation of the pear variety Dr. Jules Guyot, named `IGE 2002', was selected from a pear growing area in Catalonia. The clone was established in vitro from a 40-year-old tree, a highly recalcitrant material unable to root by cuttings. An in vitro micropropagation protocol, with an average multiplication rate of 5, a 90% rooting, and an acclimation of 79% of the plantlets, was defined. Self-rooted plants were grown in two experimental stations, covering two distinct fruit growing areas. The main agronomic characteristics of the clone `IGE 2002' were evaluated during six seasons, 1997 to 2002. Blooming and harvest period were at a similar time than `Dr. Jules Guyot'. Soluble solids concentration and acidity are also similar to `Dr. Jules Guyot'. However, at the same harvest time, a lower fruit firmness of `IGE 2002' in comparison to `Dr. Jules Guyot' indicated an advanced ripening. In addition, a finer flesh texture of `IGE 2002' than `Dr....

This study was conducted to evaluate the effect of associated consortium fungal species on the natural fermentation of the mesocarp of Pyrus communis (Pear). The combined role played by the fungi (moulds and yeasts) involve in the natural fermentation of the Pear mesocarp were also investigated. Fresh and ripe pears were washed and surface sterilized with ethanol. The mesocarp was then scraped into a bowl and covered with a net to allow the action of aerobic fermentation for 50 days. Fungi were isolated from the samples at interval of 5 days. The morphological, microscopic and biochemical characteristics as well as the fungal count were also carried out according to standard methods. The physicochemical parameters of the pear’s mesocarp such as pH, total titrable acidity (TTA), moisture contents and total reducing sugar were also determined at every 5 days according to standard methods. The results showed that there were eight strains of mould namely: Aspergillus niger, Aspergillus ...

Productivity of irrigated prickly pear cactus [Opuntia ficus-indica (L.) Miller] was studied over 3 years in central Chile using two planting densities. A low-density planting (0.25 plants/m2), traditionally favored for fruit production, had maximal fruit productivity in the 2nd year (6 Mg dry weight/ha per year). A high-density planting (24 plants/m2), which assured almost full interception of incident solar radiation, led to an extremely high shoot dry-weight productivity (50 Mg·ha-1·year-1) in the 2nd year and maximal fruit productivity (6 Mg·ha-1·year-1) in the 3rd year. Cladode dry weight tended to increase with cladode surface area. However, fruit production did not occur until the dry weight per cladode exceeded the minimum dry weight for a particular cladode surface area by at least 33 g. The year-to-year variation in fruit production apparently reflected variations in such excess dry weight and, hence, in the storage reserves of individual cladodes.

Epigenetic regulation is crucial to ensure a coordinated control of the different events that occur during fruit development and ripening. Sirtuins are NAD+-dependent histone deacetylases involved in the regulation of gene expression of many biological processes. However, their implications in the Rosaceae family remains unexplored. Accordingly, in this work, we demonstrated the phylogenetic divergence of both sirtuins among Rosaceae species. We then characterized the expression pattern of both SRT1 and SRT2 in selected pome and stone fruit species. Both SRT1 and SRT2 significantly changed during the fruit development and ripening of apple, nectarine and pear fruit, displaying a different expression profile. Such differences could explain in part their different ripening behaviour. To further unravel the role of sirtuins on the fruit development and ripening processes, a deeper analysis was performed using pear as a fruit model. In pear, PbSRT1 gene expression levels were negatively...

The storage life of ‘Alexander Lucas’ pear is limited by the occurrence of internal storage disorders during controlled atmosphere (CA). 1-Methylcyclopropene (1-MCP) can be used to delay pear ripening, however, its interaction with CA conditions is not well understood. ‘Alexander Lucas’ fruit were treated with 1-MCP at 300 nL L-1 for 24 h in air at-0.5 or 1.0 °C before being stored. Fruit were kept at-0.5 or 1.0 °C in normal air or CA (2.0 kPa O2 plus <0.7 kPa CO2). After six months of storage, superficial scald did not develop in fruit. The highest incidence of flesh browning (72.2 %) was found in air-stored fruit at-0.5 °C without 1-MCP treatment. Storage in air at 1.0 °C plus 300 nL L-1 1-MCP produced 88.8 % of healthy fruit. In contrast, 1-MCP increased the incidence of flesh and core browning under CA conditions. 1-MCP and CA maintained greener skin color and higher titratable acidity. No significant differences were found for fruit firmness, total soluble solids and ascorbi...

Over the past decade, hyperspectral imaging has been an exciting technology used in many practical fields. In agriculture, hyperspectral imaging is implemented in controlling fruit quality and analyzing specific crops in different estimated climate. Bruise damage is one of the crucial factors that influence significantly quality of fruits. This paper focuses on combining hyperspectral imaging with some supervised classification including k-nearest neighbor (k-NN) and support vector machine (SVM) algorithm to detect bruise areas on pears. Data acquisition of hyperspectral NIR reflectance images of pears was performed for choosing the feature of classification algorithms. Experiment results show the effectiveness of both methods in separating bruise from normal areas in shortest time. These results are good enough to detect the early bruise damage which is not easily recognized by conventional classification methods using human eye.

Prickly pear (Opuntia spp) fruit has received renewed interest since it contains a betalain pigment that has an attractive purple colour for the production of juice. Prickly pear juice was prepared by homogenizing the fruit and treating the pulp with 48 g of pectinase from Aspergillus niger. Titratable acidity was determined by diluting 10 ml prickly pear juice with 90 ml deionized water and titrating to pH 8.2 with 0.1 N NaOH. Brix was measured using a refractometer and ascorbic acid content assayed spectrophotometrically. Colour variation was determined colorimetrically (Hunter L.a.b.). Hunter L.a.b. analysis showed that the red purple colour of prickly pear juice had been affected by juice treatments. This was indicated by low light values of colour difference meter (CDML*), hue, CDMa* and CDMb* values. It was observed that non-treated prickly pear juice had a high (colour difference meter of light) CDML* of 3.9 compared to juice treatments (range 3.29 to 2.14). The CDML* signifi...

ABSTRACT Responses of host cells against the attack of Erwinia amylovora have not been studied well. In this research, resistance levels of pear rootstocks, OH×F40, OH×F87, OH×F69, OH×F333 and two control pear cultivars, ‘Bartlett’ (susceptible) and ‘Harrow Sweet’ (resistant), were studied by pathogen inoculation and evaluation of necrosis progress rate on in vitro shootlets. Also, generation of hydrogen peroxide (H2O2) and superoxide (O2-) radicals were traced in the course of disease progress. Pear shootlets were inoculated with E. amylovora strain Ea273 and disease progress was followed for 144 h after inoculation. H2O2 and O2- generation were traced using diaminobenzidine (DAB) and nitro blue tetrazolium (NBT), respectively. Results indicate a classification of resistance from OH×F69 > OH×F87 > Harrow Sweet > OH×F333 > Bartlett > OH×F40. H2O2 generation demonstrated an inverse relation to necrosis appearance: more tolerant cultivars and rootstocks had faster H2O2 generation rates and slower necrosis development. On the other hand, the pattern of O2- generation was not so well defined. Apparently, H2O2 plays an inhibitory role against pathogen invasion, while O2- is destructive for host tissue.

Pear (Pyrus communis L.) cultivars are self-incompatible and their adequate fruit set depends on the presence of pollinizer trees with compatibility of bloom period and alleles. This research was carried out in order to identify the self-incompatibility alleles in pear cultivars of the Iranian National Pear Collection. Partial or complete sequences of more than 200 pear S-alleles have been obtained from NCBI and aligned by ClustalW2 in order to compare their conserved regions for categorization of the sequences and subsequent primer design. All deposited S-alleles were separated based on the original species and sequence in 63 divergent sequences, and C2 and C3 conserved regions were used for FB-F/FB-R2 non-specific primer designing. Following PCR amplification of S-alleles, DraI, EcoRI, MspI and HaeIII restriction maps of amplified regions were compared to expected maps from previously identified S-alleles. The results showed homonym groups of alleles, also synonymous alleles such as S22 and S3 in the data bank. Detection of S-alleles in pear cultivars demonstrated 21, 10.5, 13.1 and 7.8% of frequencies, respectively for S1, S2, S4 and S5 alleles. Interestingly, the S42 rare allele from P. ussuriensis was detected in cultivar 'Konjuni' originating from central areas of Iran.

Programmed cell death (PCD) and secondary cell wall (SCW) thickening in pear fruit are accompanied by the deposition of cellulose and lignin to form stone cells. Metacaspase is an important protease for development, tissue renewal and PCD. The understanding of the molecular mechanism whereby pear (Pyrus) metacaspase promotes PCD and cell wall lignification is still limited. In this study, the Metacaspases gene family (PbMCs) from P. bretschneideri was identified. PbMC1a/1b was associated with lignin deposition and stone cell formation by physiological data, semiquantitative real-time polymerase chain reaction (RT-PCR) and quantitative RT-PCR (qRT-PCR). Relative to wild-type (WT) Arabidopsis, the overexpression of PbMC1a/1b increased lignin deposition and delayed growth, thickened the cell walls of vessels, xylary fibers and interfascicular fibers, and increased the expression of lignin biosynthetic genes. Yeast two-hybrid (Y2H), bimolecular fluorescence complementation (BiFC) and GST pull-down assays indicated that the PbMC1a/1b protein physically interacted with PbRD21. Simultaneously, the transient expression of PbMC1a/1b and PbRD21 led to significant changes in the expression of genes and lignin contents in pear fruits and flesh calli. These results indicate that PbMC1a/1b plays an important role in cell wall lignification, possibly by interacting with PbRD21 to increase the mRNA levels of some lignin synthesis-associated genes and promote the formation of stone cells in pear fruit.