Search Results (73)

Abnormally warm winters in recent years have accelerated flowering in fruit trees, increasing their vulnerability to late frost damage. To address this challenge, this study aimed to evaluate and compare the performance of three phenology models—the development rate (DVR), modified DVR (mDVR), and Chill Days (CD) models—for predicting full bloom dates of ‘Niitaka’ pear, using image-derived phenological observations. The goal was to identify the most reliable and regionally transferable model for nationwide application in South Korea. A key strength of this study lies in the integration of real-time orchard imagery with automated weather station (AWS) data, enabling standardized and objective phenological monitoring across multiple regions. Using five years of temperature data from seven orchard sites, chill and heat unit accumulations were calculated and compared with observed full bloom dates obtained from orchard imagery and field records. Correlation analysis revealed a strong negative relationship between cumulative heat units and bloom timing, with correlation coefficients ranging from –0.88 (DVR) to –0.94 (mDVR). Among the models, the mDVR model demonstrated the highest stability in chill unit estimation (CV = 6.3%), the lowest root-mean-square error (RMSE = 2.9 days), and the highest model efficiency (EF = 0.74), indicating superior predictive performance across diverse climatic conditions. In contrast, the DVR model showed limited generalizability beyond its original calibration zone. These findings suggest that the mDVR model, when supported by image-based phenological data, provides a robust and scalable tool for forecasting full bloom dates of temperate fruit trees and enhancing grower preparedness against late frost risks under changing climate conditions. Full article

Pear (Pyrus pyrifolia) is an important deciduous fruit tree that requires a specific period of low-temperature accumulation to trigger spring flowering. The warmer winter caused by global warming has led to insufficient winter chilling, disrupting floral initiation and significantly reducing pear yields in Southern China. In this study, we integrated targeted phytohormone metabolomics, full-length transcriptomics, and proteomics to explore the regulatory mechanisms of dormancy in ‘Mixue’, a pear cultivar with an extremely low chilling requirement. Comparative analyses across the multi-omics datasets revealed 30 differentially abundant phytohormone metabolites (DPMs), 2597 differentially expressed proteins (DEPs), and 7722 differentially expressed genes (DEGs). Integrated proteomic and transcriptomic expression clustering analysis identified five members of the dormancy-associated MADS-box (DAM) gene family among dormancy-specific differentially expressed proteins (DEPs) and differentially expressed genes (DEGs). Phytohormone correlation analysis and cis-regulatory element analysis suggest that DAM genes may mediate dormancy progression by responding to abscisic acid (ABA), gibberellin (GA), and salicylic acid (SA). A dormancy-associated transcriptional regulatory network centered on DAM genes and phytohormone signaling revealed 35 transcription factors (TFs): 19 TFs appear to directly regulate the expression of DAM genes, 18 TFs are transcriptionally regulated by DAM genes, and two TFs exhibit bidirectional regulatory interactions with DAM. Within this regulatory network, we identified a novel pathway involving REVEILLE 6 (RVE6), DAM, and CONSTANS-LIKE 8 (COL8), which might play a critical role in regulating bud dormancy in the ‘Mixue’ low-chilling pear cultivar. Furthermore, lncRNAs ONT.19912.1 and ONT.20662.7 exhibit potential cis-regulatory interactions with DAM1/2/3. This study expands the DAM-mediated transcriptional regulatory network associated with bud dormancy, providing new insights into its molecular regulatory mechanisms in pear and establishing a theoretical framework for future investigations into bud dormancy control. Full article

Pear buds exhibit inherent dormancy, during which carbohydrates play a pivotal role in dormancy release and germination. In this study, Pyrus pyrifolia ‘Cuiguan’ was employed as the experimental material to investigate the molecular mechanisms underlying flower bud dormancy release. The results revealed that the dynamic balance between starch and soluble sugar is critical for promoting dormancy release and germination in P. pyrifolia ‘Cuiguan’ flower buds. Through transcriptomic and proteomic profiling, a total of 4035 differentially expressed genes (DEGs) and 1596 differentially expressed proteins (DEPs) were identified, which were predominantly associated with carbohydrate metabolism, particularly sugar metabolism pathways. Their changes were coordinately regulated at both transcriptional and translational levels. Key structural genes involved in maltose and sucrose biosynthesis, including BAM (LOC103949270), AAM (LOC125479337, LOC103940334, and LOC103941903), SPS (LOC125475683), and INV (LOC125478747), were significantly upregulated during the germination stage, facilitating flower bud sprouting. Integrated multi-omic analysis demonstrated that starch–sugar interconversion may govern dormancy release and sustained bud growth by modulating sugar metabolism-related genes and proteins. These findings provide novel insights into the molecular mechanisms of carbohydrate biosynthesis and associated protein regulation during dormancy release and development of P. pyrifolia ‘Cuiguan’ under natural conditions. Full article

This paper proposes a cluster-based flight path construction method for automated drone-assisted pear pollination systems in orchard environments. The approach uses RGB-D (Red-Green-Blue-Depth) sensing through an observation drone equipped with RGB and depth cameras to detect blooming pear flowers. Flower detection is performed using a YOLO (You Only Look Once)-based object detection algorithm, and three-dimensional flower positions are estimated by integrating depth information with the drone’s positional and orientation data in the east-north-up coordinate system. To enhance pollination efficiency, the method applies the OPTICS (Ordering Points To Identify the Clustering Structure) algorithm to group detected flowers based on spatial proximity that correspond to branch-level distributions. The cluster centroids then construct a collision-free flight path, with offset vectors ensuring safe navigation and appropriate nozzle orientation for effective pollen spraying. Field experiments conducted using RTK-GNSS-based flight control confirmed the accuracy and stability of generated flight trajectories. The drone hovered in front of each flower cluster and performed uniform spraying along the planned path. The method achieved a fruit set rate of 62.1%, exceeding natural pollination at 53.6% and compared to the 61.9% of manual pollination. These results demonstrate the effectiveness and practicability of the method for real-world deployment in pear orchards. Full article

Kasugamycin (KSM) is easily affected by photolysis, acid–base destruction, and oxidative decomposition in the natural environment, leading to its poor durability and low effective utilization rate, which affects its control effect on plant bacterial diseases. Nanomaterials modified with environment-responsive agents enable the control of the release of pesticides through intelligently responding to external stimuli, thereby improving efficacy and reducing environmental impact. In this study, a pH-responsive controlled release system was constructed using zeolitic imidazolate frameworks (ZIF-93) for the sustained and targeted delivery of KSM. The synthesized KSM@ZIF-93 exhibited a diameter of 63.93 ± 11.19 nm with a drug loading capacity of 20.0%. Under acidic conditions mimicking bacterial infection sites, the Schiff base bonds and coordination bonds in ZIF-93 dissociated, triggering the simultaneous release of KSM and Zn²⁺, achieving a synergistic antibacterial effect. Light stability experiments revealed a 34.81% reduction in UV-induced degradation of KSM when encapsulated in ZIF-93. In vitro antimicrobial assays demonstrated that KSM@ZIF-93 completely inhibited Erwinia amylovora at 200 mg/L and had better antibacterial activity and persistence than KSM and ZIF-93. The field experiment and safety evaluation showed that the control effect of KSM@ZIF-93 on pear fire blight at the concentration of 200 mg/L was (75.19 ± 3.63)% and had no toxic effect on pollen germination. This pH-responsive system not only enhances the stability and bioavailability of KSM but also provides a targeted and environmentally compatible strategy for managing bacterial infections during the flowering period of pear trees. Full article

Chlorophyll content is a critical indicator of the physiological status and fruit quality of pear trees, with Soil Plant Analysis Development (SPAD) values serving as an effective proxy due to their advantages in rapid and non-destructive acquisition. However, current remote sensing-based SPAD retrieval studies are primarily limited to single phenological stages or rely on a narrow set of input features, lacking systematic exploration of multi-temporal feature fusion and comparative model analysis. In this study, pear leaves were selected as the research object, and Sentinel-2 remote sensing data combined with in situ SPAD measurements were used to conduct a comprehensive retrieval study across multiple growth stages, including flowering, fruit-setting, fruit enlargement, and maturity. First, spectral reflectance and representative vegetation indices were extracted and subjected to Pearson correlation analysis to construct three input feature schemes. Subsequently, four machine learning algorithms—K-Nearest Neighbors (KNN), Random Forest (RF), Support Vector Machine (SVM), and an Optimized Integrated Algorithm (OIA)—were employed to develop SPAD retrieval models, and the performance differences across various input combinations and models were systematically evaluated. The results demonstrated that (1) both spectral reflectance and vegetation indices exhibited significant correlations with SPAD values, indicating strong retrieval potential; (2) the OIA model consistently outperformed individual algorithms, achieving the highest accuracy when using the combined feature scheme; (3) among the phenological stages, the fruit-enlargement stage yielded the best retrieval performance, with R² values of 0.740 and 0.724 for the training and validation sets, respectively. This study establishes a robust SPAD retrieval framework that integrates multi-source features and multiple models, enhancing prediction accuracy across different growth stages and providing technical support for intelligent orchard monitoring and precision management. Full article

To calyx persistence in Korla fragrant pear (Pyrus sinkiangensis) significantly impacts fruit marketability, with persistent calyx causing up to 40% reduction in premium-grade fruit yield. Investigating the hormonal mechanisms underlying calyx abscission and persistent in Korla Fragrant Pear, we performed comprehensive phytohormone profiling using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS; EXIONLC system coupled with SCIEX 6500 QTRAP+). Flowers from first-position (persistent-calyx) and fourth-position (deciduous-calyx) inflorescences were collected at six developmental stages (0–10 days after flowering). Fourteen endogenous hormones—ACC, ME-IAA, IPA, TZR, SA, IAA, ICA, IP, tZ, DHJA, ABA, JA-ile, cZ, and JA—were identified in the calyx during the flowering stage. The calyx abscission rate was significantly higher in the fourth position (79%) compared to the first position (32%). ACC and ABA are closely linked to abscission, with increased ACC at 0 DAF signaling early abscission and ABA accumulation accelerating late abscission at 8 DAF. Auxin exhibited spatiotemporal specificity, peaking in first-order flowers at 4–6 DAF, potentially inhibiting abscission by maintaining cell activity. Cytokinins generally decreased, while jasmonates significantly increased during the fourth-position anthesis stage 8–10 DAF, suggesting a role in stress-related senescence. By systematic analysis of the flowers at the first order (persistent calyx) and the fourth order (deciduous calyx) from 0 to 10 days after anthesis, we found three key stages of hormone regulation: early prediction stage (0–2 DAF), ACC accumulation at the fourth order was significantly higher than that at the first order at 0 days after anthesis, ACC accumulation at the early stage predicted abscission; During the middle maintenance stage (4–6 DAF), the accumulation of cytokinin decreased significantly, while the accumulation of IAA increased significantly in the first position (persistent calyx); Execution Phase (8–10 DAF), ABA reached its peak at 8 DAF, coinciding with the final separation time. JA played an important role in the late stage. Gibberellin was undetected, implying a weak association with calyx abscission. Venn diagram identified N6-(delta 2-Isopentenyl)-adenine (IP) in first-position flowers, which may influence calyx persistence or abscission. These findings elucidate hormone interactions in calyx abscission, offering a theoretical basis for optimizing exogenous hormone application to enhance fruit quality. Full article

Studying fruit genetic trends, heterosis, and growth traits in pear hybrid progeny provides the foundation for variety breeding. The aim of this research is to reveal the trait performance of the hybrid progeny of Chinese white pear and Western pear and provide a theoretical basis for other breeders to predict the trait performance of their hybrid progeny when selecting Eastern pear and Western pear as parents. Our research team constructed a ‘Yuluxiang’ × ‘Xianghongli’ interspecific hybrid population in 2015, and in 2023, we conducted a two-year investigation of 16 traits in 140 hybrid progeny, including 11 fruit traits and 5 growth traits, and analyzed and compared the genetic variation and heterosis of traits, as well as the correlation between various traits. The results showed that the hybrid progeny was widely segregated for single fruit weight (FW), soluble solid (SS) content, and titratable acid (TA) content and conformed to a normal distribution, with quantitative genetic traits under polygenic control. The highest two-year coefficients of variation for TA were 54.42% in 2023 and 39.17% in 2024. A genetic trend of decreasing FW was observed, which was greatly influenced by the male sex. The ratio of soft soluble flesh to crispy flesh was 1:1, and the gene controlling this trait may be a quality trait controlled by a single gene. The traits that showed transgressive heterosis for two years included fruit longitudinal diameter (FLoD), fruit shape index (FSI), and TA, and those that showed negative heterosis included FW, SS, leaf longitudinal diameter (LLoD), and leaf lateral diameter (LLaD). Correlation analysis indicated that the progeny of crosses in this combination, which had red fruit skin, may also present red early flowering color (EFC) and young leaf color (YLC), reddish brown annual branch color (ABC), and lower FSI, fruit stalk length (FSL), LLaD, and TA. Thus, at the seedling stage, individuals with red-colored fruit may be screened by observing the color of young leaves and young stems and the lateral diameter of the leaves. Principal component analysis showed that among the 16 traits included in six principal components, peel color (PC), FLoD, 2024SS, fruit tape (FT), and FSI were the main factors causing differences in fruit phenotypes. This study systematically elucidated the genetic trends of agronomic traits in pears and will provide a theoretical basis for the selection of parents and early selection of hybrid progeny in pear hybrid breeding. Full article

B-box (BBX) genes, as zinc finger transcription factors (TFs), play essential roles in regulating plant growth and development. In this study, we identified 23 BBX genes in the pomegranate (Punica granatum L.) genome. These genes were classified into five groups based on the distribution of conserved domains and phylogenetic relationships. Each PgBBX group exhibited similar molecular weights, theoretical isoelectric points (pI), gene structures, and conserved motif distributions compared with BBX members in Arabidopsis and Chinese white pear in corresponding groups. Syntenic analysis revealed segmental duplications of eight PgBBX gene pairs within the pomegranate genome. Additionally, twenty-seven and thirty-one orthologous BBX pairs were identified between PgBBX and AtBBX, and PgBBX and PbBBX, respectively. Promoter analysis revealed the presence of five types of cis-acting elements responding to light, phytohormones, stress, developmental signaling, and potential transcription factors (TFs). GO enrichment analysis confirmed that most PgBBX genes function as TF involved in plant growth and development. RNA-seq data indicated that PgBBX5 was primarily expressed in leaves and flowers, with increased expression in different fruit tissues during ripening. Moreover, PgBBX5 showed a high degree of sequence similarity with anthocyanin-related homologs, including AtBBX24, PhBBX24, FaBBX24, MdCOL4, and PyBBX24. During the ripening of ‘Tunisia’ fruits, PgBBX5 expression was positively correlated with the dynamic changes in anthocyanin content and the expression of key anthocyanin biosynthetic and transport genes. Furthermore, subcellular localization suggested that PgBBX5 encodes a nuclear-localized protein. This study provides a comprehensive characterization of the PgBBX family, offering valuable insights into the mechanisms underlying anthocyanin accumulation during pomegranate fruit ripening. Full article

In this study, the effects of natural grass cultivation and clear cultivation on the physiological characteristics of Korla fragrant pear during fruit development and storage were investigated, providing a scientific basis for high-quality fragrant pear cultivation. Sugar components, enzyme activities, and gene expression levels in the pulp and peel were comprehensively analyzed during fruit development and storage. A classification model was constructed using machine learning algorithms (RF, KNN, SVM), and particle swarm optimization (PSO) was employed to identify key factors. The results showed that natural grass cultivation significantly enhanced sugar accumulation in the fruits, particularly at 120 and 150 days after flowering, with fructose content increasing by 9.09 mg·g⁻¹ and 12.59 mg·g⁻¹, respectively, and glucose content also rising significantly. Additionally, natural grass cultivation promoted the relative expression levels of GK, PFK, and FK genes in the pulp. During fruit storage, enzyme activities in the natural grass cultivation group were consistently higher than those in the clear cultivation group across different periods, with PFK activity being 23.73 U/L higher at 150 days of storage. The model identified the activities of glyceraldehyde kinase, phosphofructokinase, and fructokinase as key factors influencing sugar content. A significant negative correlation was observed between peel phosphofructokinase activity and fruit fructose content, though this relationship requires further investigation. This study elucidates the regulatory mechanism by which cultivation methods affect fruit quality through enzyme activity and photosynthetic product distribution. Our findings provide a critical scientific foundation for the high-quality cultivation of Korla fragrant pear and are expected to advance the efficient development of the fragrant pear industry, helping farmers improve both fruit quality and income. Full article

Recent meteorological variability in winter and spring complicates predicting and managing frost damage in apples and pears. This study investigated the relationship between frost injury during the flowering stages of apples (‘Hongro’ and ‘Fuji’) and pears (‘Wonwhang’ and ‘Niitaka’) and weather conditions across regions at varying altitudes. Orchards were categorized into coastal, inland, mid-mountainous, and mountainous regions, and flowering stages and frost injury were analyzed. The flowering period of apples, from the onset of blooming to full bloom, averaged approximately 15 days, which was about 3 to 5 times longer than that of pears. Furthermore, the total flowering duration of apples was 1.5 to 2.0 times longer than that of pears. Additionally, flowering exhibited a tendency to be delayed at higher altitudes. However, orchards situated in mid-mountainous regions experienced earlier flowering compared to those in other regions. Among the two apple cultivars, the average frost damage was more severe in central flowers than in lateral flowers and was relatively higher in ‘Fuji’ than in ‘Hongro’. In pears, frost damage was most prevalent in the first to fourth flowers within the inflorescence, with ‘Wonhwang’ exhibiting relatively greater susceptibility than ‘Niitaka’. Across different cultivation regions, severe frost damage was observed in orchards located in mid-mountainous areas for both fruit species and cultivars. The severity of frost damage followed the order mid-mountainous, mountainous, plain, and coastal regions. Minimum temperatures were lowest in mid-mountainous and mountainous regions, while daily temperature differences were largest in mid-mountainous regions. Meteorological analysis (1981 to 2022) revealed consistent trends, with an increase in daily temperature range in recent years. These findings highlight the vulnerability of mid-mountainous orchards due to flowering stages overlapping with coastal and plain regions, exposing them to lower temperatures and larger temperature differences. Further studies on temperature variability are essential to mitigate frost damage risks. Full article

CH201/FRED^® is a novel red-blush pear cultivar with long-term storage potential and a prolonged shelf life. However, it is prone to controlled atmosphere (CA)-related disorders, particularly cavities. This study explored the impact of the balance between vegetative growth and crop load on the development of CA-related disorders during storage. Treatments involving the removal of two-thirds of floral bouquets (Fl_Th) and the shortening of branches by two-thirds (Pr) at the bud stage (late balloon stage) promoted the growth of 1-year-old shoots, which correlated with an increased incidence of cavities and reduced calcium levels in the pears. The Fl_Th treatment resulted in larger fruits with a higher total soluble solid content, a greater force required to puncture the skin and flesh, and a higher incidence of cavities than the Pr treatment. These findings demonstrate that both crop load and the leaf area-to-crop load ratio significantly influence the susceptibility of CH201/FRED^® pears to CA-related disorders during storage. Full article

The ‘Jingbaili’ pear is a national geographical indication product of China, featuring an oblate shape and being rich in nutrients. But the quality of the ‘Jingbaili’ pear is unstable. Xenia can cause changes in the quality of pears, but the effect of xenia on the ‘Jingbaili’ pear is unknown, and its mechanism is still unclear. In order to clarify the effect of pollination on the fruit quality of the ’Jingbaili’ pear, this research pollinated ‘Jingbaili’ pear flowers with the pollen of ‘Yali’ (JY), ‘Suli’ (JS) and ‘Huangli’ (JH). The results indicated that the mass, transverse diameter and longitudinal diameter of the JY group were significantly higher than the JS group and JH group. On the other hand, the pears of the JY group and JS group obtained higher soluble sugar content. The aroma content of characteristic compounds was higher in the JY group than in the JS group and JH group. Multivariate analysis revealed significant differences in the nonvolatile metabolites among the JY group, JS group and JH group, potentially explaining the variations in the nutritional and flavor compounds of the pears. Furthermore, this research investigated metabolic changes in the pears during development and ripening under the three types of pollination. The results showed that amino acid metabolism differed among these pollination types during development. These differences may be the cause of the observed variations in the pears. This research clarified the effect of xenia on the nutritional components and flavor substances in the ‘Jingbaili’ pear and could provide data support for improving the quality of the ‘Jingbaili’ pear. Full article

Zaosu pear (Pyrus ssp. Va., Zaosu) is the main variety of pear cultivated in Gansu Province. Tree shape selection is important in pear cultivation: reasonable tree shapes affect the growth and development of fruit trees and fruit quality, which, in turn, affect the economic benefits of orchards. In this study, Zaosu pear was used as a test material, and five different tree shapes—Y, trunk, single-arm, double-arm, and spindle shapes—were studied regarding three aspects, namely, branching and leafing parameters, light radiation parameters, and root distribution, in order to provide a theoretical basis for the selection of pear tree shapes in arid areas. The results showed that the single-arm and double-arm shapes had the highest fruit weight per fruit values, reaching 280.06 g and 278.27 g, respectively, and the difference in soluble solids—12.42 mg·g⁻¹ and 12.91 mg·g⁻¹, respectively—was not significant; the mu yield of the single-arm shape was 3282 kg; and the yield of a single tree was 39.54 kg, which was the highest for the five tree shapes. The trees mainly had short fruiting branches when they entered the fruiting stage, and the double-arm shape had the highest number of short fruiting branches, which was significantly higher than those of the other tree shapes. Correlation analysis revealed that the number of long fruiting branches was significantly and positively correlated with axillary flower buds. The distribution of light intensity for all five tree shapes showed a gradual increase from bottom to top and from inside to outside, and the single-arm and double-arm shapes had a uniform distribution of light intensity, which translated into better growth and fruiting potential. The trunk shape had the largest leaf area index, resulting in too much depression within the canopy and reducing light, while the single-arm and double-arm shapes had the smallest leaf area indexes, resulting in the light being evenly distributed inside and outside the canopy, and the percentage of light intensity was greater than 50% in all cases, reaching up to 80%. The double-arm form had the highest chlorophyll a content of 24.55 mg·g⁻¹, implying the ability to convert more light energy into chemical energy, and the content of chlorophyll a + b was highest in the single-arm form and the double-arm form, with values of 31.13 mg·g⁻¹ and 33.65 mg·g⁻¹. The total length of the root system and the total surface area of the root system for the single-arm shape were the largest, i.e., 558,550.64 cm and 79,252.32 cm², respectively, indicating that it has stronger adaptability and resource acquisition ability compared to the other tree shapes. In conclusion, the single-arm form is more suitable for planting in arid areas. Full article

In this study, 53 pear genotypes were evaluated, including 19 Asian varieties, 7 botanical species and 13 new interspecific hybrids. The ploidy level and nuclear DNA content were determined by flow cytometry. In addition, the morphological traits and their possible correlations with the genome size were analyzed. One triploid genotype was found. The Asian varieties had a lower average genome size (553.4 Mbp) than the European varieties (564.1 Mbp). The average nuclear DNA content was 1.14 pg/2C for the diploid genotypes and 1.77 pg/2C DNA for the triploids. The Asian varieties had significantly larger leaves than the European ones. Pyrus calleryana had the smallest flowers and P. Caucasica the largest, but the varieties showed no significant differences in flower size. The pollen grain size ranged from 37.7 to 59.0 μm. However, there were no significant correlations between the genotype groups or genome sizes. The Asian cultivars had, on average, smaller stomata (28.4 μm) than the European cultivars (31.6 μm). The largest stomata size was measured for the triploid genotypes (37.9 μm). There was a positive correlation between the genome size and stomatal length and a negative correlation between the genome size and leaf length, leaf width and flower diameter. Full article