Genetic & Breeding · Germplasm Resources · Molecular Biology

• Phenotypic Diversity Evaluation of Shoots and Leaves in 264 Pear Germplasm Accessions
• XU Huinan, GAO Mengjie, QI Kaijie, CUI Yanbo, WU Xiao, TAO Shutian, ZHANG Shaoling, YIN Hao
• Acta Horticulturae Sinica. 2026, 53(5): 1237-1252. DOI:10.16420/j.issn.0513-353x.2025-0325
• Abstract ( 89 ) HTML ( 56 ) PDF (4673KB) ( 56 ) 　　　

• Using 264 pear germplasm accessions preserved in the Pear Germplasm Repository of Nanjing Agricultural University as the research materials，22 descriptive traits，including one-year-old shoot color and lenticel density，and 10 quantitative traits，including petiole length and leaf length，were investigated. The Shannon-Wiener diversity index，coefficient of variation，comparative analyses of inter- and intra-population diversity，correlation analysis and principal component analysis of quantitative traits，and cluster analysis were conducted. The results showed that the diversity indices of the descriptive and quantitative traits ranged from 0.025 to 1.637 and from 2.004 to 2.087，the diversity of quantitative traits was markedly higher than that of descriptive traits. Among the descriptive traits，young leaf color had the highest diversity index（H' = 1.637）. The coefficients of variation of the 10 quantitative traits ranged from 11.18% to 36.56%，with leaf area showing the highest value（CV = 36.56%）. Both inter- and intra-population variation of the nine quantitative traits related to shoots and leaves were relatively high，indicating that both contributed substantially to the phenotypic diversity of pear germplasm resources. Based on the comprehensive analysis of correlation and principal component analysis，leaf area，one-year shoot length，and flower bud length can serve as important indicators for evaluating the variation in shoot and leaf traits. Cluster analysis divided the 264 pear germplasm accessions into five groups. Pyrus communis could be distinguished from most Oriental pears，whereas P. bretschneideri and P. pyrifolia within the Oriental pear group did not form independent clusters but showed an intermingled distribution.

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• Comparative Transcriptomic Analysis of the Effects of Storage Temperature on Peel De-greening of Postharvest Thai Green Pomelo
• WANG Bin, CAO Qiuyan, YUAN Xiao, ZHU Yunna, HUANG Changjian, LIU Tangmao
• Acta Horticulturae Sinica. 2026, 53(5): 1253-1273. DOI:10.16420/j.issn.0513-353x.2025-0194
• Abstract ( 53 ) HTML ( 31 ) PDF (9036KB) ( 31 ) 　　　

• The peel color is a critical indicator influencing the commercial value of Thai green pomelo（Citrus maxima）fruit. However，the effects of storage temperature on peel color alterations remain unclear. In this study，fruit at 80% maturity were stored at 5，15，and 25 ℃ for 15 d to investigate temperature-dependent peel color changes through comparative transcriptomic analyses integrated with phenotypic and physiological data. The results showed that storage temperature significantly affected the peel color of Thai green pomelos. Storage at 5 ℃ delayed the de-greening，whereas rapid changes in de-greening were occurred under 15 and 25 ℃ conditions. After 15 d of storage，the total chlorophyll contents respectively decreased by 21.93%，64.53% and 86.74% at 5，15 and 25 ℃，while total flavonoid contents increased by 8.56%，27.03% and 35.46%，respectively. Compared to pre-storage（0 d），the differentially expressed genes（DEGs）identified after 5 d of storage at 5 and 15 ℃ were significantly enriched in several pathways，plant hormone signal transduction，while DEGs from storage at 25 ℃ were significantly enriched in pathways carbon metabolism. After 5 d of storage，DEGs generated at 15 or 25 ℃ compared to those at 5 ℃ were significantly enriched in pigment biosynthesis or metabolism-related pathways，such as porphyrin and chlorophyll metabolism，photosynthetic antenna proteins，the phenylpropanoid biosynthesis，and flavonoid biosynthesis. DEGs that were upregulated were also significantly enriched in the phenylpropanoid biosynthesis and porphyrin and chlorophyll metabolism pathways，weighted gene co-expression network analysis revealed that genes in the magenta and yellow modules were negatively correlated with total chlorophyll content，while that in the brown module showed a significant positive correlation with total chlorophyll content. Furthermore，119 transcription factor genes that closely related to the process of peel de-greening were identified，with the highest numbers belonging to the MYB，ERF，and bHLH families. Additionally，strong correlations were observed between the expression of MYB，ERF，and bHLH transcription factor genes and genes related to chlorophyll degradation. qRT-PCR analysis indicated that storage at 15 and 25 ℃ significantly upregulated the expression of genes related to chlorophyll metabolism and flavonoid biosynthesis during the early storage period. In conclusion，storage temperature significantly affects the de-greening of Thai green pomelo peels. Storage at 5 ℃ effectively delays the de-greening，while storage at 15 and 25 ℃ accelerates that progress. 15 and 25 ℃ storage facilitated the de-greening by influencing the expression of genes associated with chlorophyll metabolism and flavonoid biosynthesis，possibly involving MYB，ERF，and bHLH transcription factors induced by these temperatures in Thai green pomelos.

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• Cloning and Functional Analysis of Mulberry MaNAC90 Gene Under Drought Stress
• HUANG Renwei, LI Xiaodong, DENG Hongmei, YANG Yan, ZENG Rui, YANG Cairong
• Acta Horticulturae Sinica. 2026, 53(5): 1274-1284. DOI:10.16420/j.issn.0513-353x.2025-0214
• Abstract ( 43 ) HTML ( 20 ) PDF (5302KB) ( 20 ) 　　　

• A NAC transcription factor gene MaNAC90 was cloned from Morus alba‘Deguo 1’. The open reading frame of MaNAC90 was 732 bp，encoding 243 amino acids with molecular weight 27.436 kD and isoelectric point 5.32. MaNAC90 contained one NAC domain and belonged to TERN group，was localized in the nucleus and the cell membrane. Under simulated drought stress（200 mmol · L^-1 mannitol），transgenic Arabidopsis expressing MaNAC90 exhibited a significant reduction in germination rate，a notable decrease in root length，an increased severity of seedling wilting，and significantly increased MDA content and electrolyte leakage，along with significantly decreased expression of RD22 and RD29B when compared to wild-type plants. These results preliminary indicated that MaNAC90 plays a negative regulatory role in response to drought stress.

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• Alginate Oligosaccharides Induced CsWRKY46 to Regulate Cucumber Response to Cold Stress and Transcriptome Analysis
• ZHU Fangyi, SU Hongling, GU Linghe, ZHANG Chong, PANG Hongbo, TONG Deli, ZHANG Ying
• Acta Horticulturae Sinica. 2026, 53(5): 1285-1300. DOI:10.16420/j.issn.0513-353x.2025-0354
• Abstract ( 29 ) HTML ( 9 ) PDF (4117KB) ( 9 ) 　　　

• This paper aims to explore the molecular mechanism of CsWRKY46 gene induced by alginate oligosaccharides in cucumber response to cold stress. In this study，cucumber CU2（wild type） and CsWRKY46 gene knockout type were used as materials，and 0.8% alginate oligosaccharides was sprayed before 4 ℃ cold stress treatment. The effects of alginate oligosaccharides on antioxidant enzyme activity，malondialdehyde content and osmotic adjustment substance content of cucumber seedlings were analyzed，and transcriptome sequencing analysis was carried out. The results showed that the pretreatment of alginate oligosaccharide significantly improved the antioxidant capacity and cold tolerance of cucumber seedlings under cold stress. Transcriptome sequencing results showed that the differentially expressed genes induced by alginate oligosaccharides were mainly enriched in plant hormone signal transduction and protein processing，among which the gene expression of abscisic acid and brassinolide signaling pathways was significantly up-regulated. These results suggest that alginate oligosaccharides may enhance the tolerance of cucumber to cold stress by regulating CsWRKY46 gene and its downstream signaling pathway.

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• Screening and Evaluation of Radish Cultivars Suitable for Pickling
• LIU Chen, XUE Rui, LIU Xianxian, XU Wenling, CHANG Lichun, WEI Zihao, YANG Meng, WANG Shufen
• Acta Horticulturae Sinica. 2026, 53(5): 1301-1314. DOI:10.16420/j.issn.0513-353x.2025-0127
• Abstract ( 25 ) HTML ( 18 ) PDF (2024KB) ( 18 ) 　　　

• To provide basis for cultivars selection and breeding for dried radish pickling，30 radish cultivars of different types were analyzed in this study. A total of 13 quality indexes of radish before or after pickling were detected and then analyzed by correlation analysis and principal component analysis. The radish materials were classified by clustering analysis，and the evaluation model was establish by regression analysis. In addition，the relationships between cellular morphology and hardness of fresh radish were analyzed through paraffin observation. The result showed that there were different variation coefficients of the 13 quality indexes in 30 radish cultivars，ranging from 17.17% to 71.83%. Except for pectin content in radish before processing and vitamin C content in radish after processing，all other indexes showed significant or extreme significant correlation to at least one other index. Among which，7 pairs were significantly correlated and 9 pairs were extremely significantly correlated. Further，5 principal components were extracted by principal component analysis，and the cumulative contribution rate reached to 75.64%. Through clustering analysis，30 radish cultivars were divided into two classes. The first class，which obtained higher scores，was mainly consisted by cultivars with green peel and green flesh，and the second class was mainly consisted by red radishes（red peel and white flesh）and white radishes（white peel and white flesh）. The optimal regression equation was established as：Y =-2.559 + 0.096 × Hardness + 0.034 × Vitamin C content of radish before processing + 0.695 × Free amino acid content of radish before processing + 0.064 × Cellulose ontent of radish before processing. Among the indexes，hardness had the greatest impact on model evaluation score. By section observation，hardness of sample was found significantly negatively correlated to the area，perimeter of cortical cell，and significantly positively correlated to the length-width ratio of cortical cell，the correlation coefficients were-0.41，-0.42 and 0.43，respectively. Using the evaluation model established in this study，the cultivars with green peel and green flesh were more suitable for pickling，among which‘Shawoqing’and‘Shengluocuiyu’were the best cultivars.

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• Study on the Function of ABC Transporter Gene LeABC2 in Thermotolerance of Lentinula edodes
• WU Yulong, WANG Yifei, LIU Gaolei, WANG Lu, ZHAO Zhidong, WANG Zhuoren, XIAO Yang
• Acta Horticulturae Sinica. 2026, 53(5): 1315-1328. DOI:10.16420/j.issn.0513-353x.2025-0545
• Abstract ( 23 ) HTML ( 16 ) PDF (3376KB) ( 16 ) 　　　

• In this study，thermotolerance phenotypes of 126 Lentinula edodes strains were evaluated. Through genome-wide association analysis，genetic loci associated with thermotolerance in L. edodes were identified. Further investigation revealed a significant correlation between the ABC transporter gene LeABC2 and thermotolerance in L. edodes. Upon silencing the LeABC2 gene via RNAi，the recovery growth rates of the transformant strains after high-temperature stress were significantly enhanced，and the critical high-temperature thresholds were higher compared to the wild-type strain. These results indicated that the LeABC2 gene negatively regulates the mycelial thermotolerance of L. edodes.

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• Cloning and Functional Analysis of Citrullus lanatus Ovate Family Protein Gene ClOFP16
• CAI Zeyu, LI Ai, ZHU Jiawei, DENG Man, JIN Yuxuan, ZHANG Weihua, WU Ying
• Acta Horticulturae Sinica. 2026, 53(5): 1329-1342. DOI:10.16420/j.issn.0513-353x.2025-0571
• Abstract ( 21 ) HTML ( 6 ) PDF (6640KB) ( 6 ) 　　　

• Ovate family proteins（OFP）constitute a class of plant-specific transcription factors implicated in intracellular signal transduction and biosynthetic processes in plants. Utilizing the watermelon cultivar‘TN07011’，the coding sequence（CDS）of ClOFP16 were isolated and performed functional characterization. Results demonstrate that ClOFP16 comprises 1 020 base pairs，encoding a protein of 339 amino acids. The encoded protein harbors an N-terminal DNA-binding domain and a C-terminal conserved Ovate domain. Subcellular localization assays confirmed the nuclear localization of ClOFP16. RT-qPCR analysis demonstrated that ClOFP16 transcript abundance was significantly upregulated under salt and 4 ℃ cold stress，but downregulated under drought stress. Arabidopsis thaliana overexpressing ClOFP16 exhibited reduced seed longitudinal diameter in T₃ generation. Under salt and low-temperature stress conditions，T₃ generation plants exhibited a significant upregulation of ClOFP16 expression. Concurrently，the activities of the antioxidant enzymes SOD，POD，and CAT were markedly increased. Furthermore，total chlorophyll content and soluble protein content were significantly elevated，while the accumulation of malondialdehyde（MDA）was reduced. Collectively，these findings implicate ClOFP16 in pivotal roles governing plant growth and development，as well as in mediating adaptive responses to abiotic stress.

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• Identification and Low Temperature Stress Responsive Expression Analysis of TIFY Gene Family in Melon
• CAO Lei, DU Ping, YANG Riling, ZHOU Yuhao, HOU Juan, LI Xiang, WANG Panqiao, LI Lili, LUO Chen, LI Qiong, MAO Wenwen, HU Jianbin
• Acta Horticulturae Sinica. 2026, 53(5): 1343-1356. DOI:10.16420/j.issn.0513-353x.2025-0225
• Abstract ( 26 ) HTML ( 9 ) PDF (2845KB) ( 9 ) 　　　

• To investigate the role of the TIFY gene family in the low temperature stress response of melon（Cucumis melo L.），genome-wide identification of TIFY family members was performed using bioinformatics approaches. Tissue-specific expression patterns and low temperature stress responsive profiles were further analyzed through transcriptome sequencing and quantitative reverse transcription polymerase chain reaction technology. The results demonstrated that a total of 15 TIFY family genes were identified in melon，classified into four subfamilies：JAZ，TIFY，ZIM，and PPD，and distributed across nine chromosomes. Tissue-specific expression analysis revealed that CmTIFY genes were expressed in various tissues. Among them，CmTIFY5A，CmTIFY5B，CmTIFY5C，CmTIFY5D and CmTIFY9B exhibited higher expression levels in flowers compared to other tissues. With fruit ripening，the gene expression level of CmTIFY5B gradually increased，whereas that of CmTIFY6B gradually decreased. CmTIFY5B and CmTIFY6B may be involved in the regulation of melon fruit ripening and quality formation. The expression levels of most CmTIFY genes were up regulated under low temperature stress，among which CmTIFY5B and CmTIFY5C were most significantly up regulated under low temperature.

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• Phenotypic Diversity of Populations of Germplasm Resources of Wild Tree Peony in Qinling and Ziwuling Mountain Areas
• YUAN Qing, ZHAO Xiangqian, LU Pinjie, ZHANG Yanlong, ZHANG Xiaoxiao
• Acta Horticulturae Sinica. 2026, 53(5): 1357-1370. DOI:10.16420/j.issn.0513-353x.2025-0637
• Abstract ( 23 ) HTML ( 8 ) PDF (2282KB) ( 8 ) 　　　

• To clarify the phenotypic diversity and variation patterns of major wild tree peony resources in the Qinling and Ziwuling regions of Shaanxi Province，eight natural populations representing Paeonia rockii，P. jishanensis，P. qiui and P. ostii（two populations each）were investigated. Twenty phenotypic traits of leaves，flowers and fruits were measured and analyzed using nested ANOVA，Shannon diversity index and two-way hierarchical clustering. The results showed：（1）Nineteen traits，except seed diameter，exhibited highly significant interspecific differences；width of a binate leaf and filament length differed significantly among populations，while fruit pod width differed significantly within populations. The mean phenotypic differentiation coefficient（VST）was 55.76%，indicating that phenotypic variation is mainly driven by genetic differentiation.（2）Across the four species，the Shannon phenotypic diversity index（H）ranged from 1.55 to 1.68 and the coefficient of variation（CV）from 10.44% to 17.38%，consistently revealing abundant phenotypic variation with P. rockii showing the highest diversity.（3）Two-way hierarchical clustering grouped the eight populations strictly according to species into two major clusters and organized the 20 traits into four functional modules representing floral，foliar，fruit and anther haracters.（4）Linear mixed-model analysis further revealed that temperature and precipitation significantly explained variation in several floral and fruit traits（marginal R² up to 0.474），although population genetic structure remained the dominant source of phenotypic differentiation. Overall，wild tree peonies display pronounced genetic variation at interspecific，inter-population and intra-population levels，with greater variation among populations than within populations，while environmental factors also contribute significantly to key traits. Therefore，as many wild peony populations as possible should be protected in their habitats. Suggested that more populations with less individuals in each population should be taken as samples when researchers collect germplasm for studies about off-site conservations and genetic improvements.

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• Cloning of FAD2 Genes in Three Paphiopedilum Species and Comparative Analysis of Their Expression in Responses to Chilling Stress
• HUANG Jiuyan, DUAN Xiaoqian, FU Yue, CHANG Wei, DING Yong
• Acta Horticulturae Sinica. 2026, 53(5): 1371-1381. DOI:10.16420/j.issn.0513-353x.2025-0442
• Abstract ( 21 ) HTML ( 13 ) PDF (3398KB) ( 13 ) 　　　

• Low temperature is a critical environmental factor limiting the survival and reproduction of Paphiopedilum species. Fatty acid desaturase 2（FAD2）plays a pivotal role in plant chilling tolerance by dynamically regulating the unsaturation of membrane lipids. Here，the sequence characteristics of FAD2genes and their expression regulation under low-temperature conditions were systematically elucidated in

  three Paphiopedilum species with distinct ecological adaptations（P. purpuratum，P. dianthum，and P. armeniacum） through gene cloning，bioinformatics analysis，and qRT-PCR methods. The results revealed that the physicochemical parameters，spatial conformations，and transmembrane characteristics of the three FAD2 proteins were highly conserved. However，their subcellular localization predicted by WoLF PSORT exhibited marked species specificity：PaFAD2 from P. armeniacum showed predominant plastid localization，while PpFAD2 and PdFAD2 exhibited preferential accumulation in the plasma membrane/ endoplasmic reticulum and diverse endomembrane systems，respectively. Under 4 ℃ chilling stress，the PaFAD2 gene was rapidly activated at the early stress stage（24 h treatment group）and maintained high expression levels；whereas，PpFAD2 or PdFAD2 genes displayed delayed response or weak induction characteristics，respectively. Integrating biogeographical distribution patterns，it was hypothesized that the rapid transcriptional response of PaFAD2 in P. armeniacum might be evolutionarily associated with long-term adaptation to high-altitude habitats，whereas P. purpuratum and P. dianthum appeared to utilize differential FAD2 expression strategies to achieve an adaptive trade-off between cold resistance and metabolic efficiency.

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• The Flavonol Biosynthetic Mechanism During Post-Anthesis Color Change in Lotus filicaulis
• SHANGGUAN Julong, TONG Linna, WEI Chao, GAO Ruifang
• Acta Horticulturae Sinica. 2026, 53(5): 1382-1394. DOI:10.16420/j.issn.0513-353x.2025-1298
• Abstract ( 19 ) HTML ( 11 ) PDF (3154KB) ( 11 ) 　　　

• Post-anthesis color change（PACC），a process in which Lotus filicaulis flowers transition from yellow to red，is an adaptive strategy to enhance pollination efficiency. While existing studies have primarily focused on anthocyanins，the regulatory role of flavonols and their synergistic relationship with anthocyanins remain unclear. In this study，flavonol-targeted metabolomics and transcriptomic analyses were integrated to identify flavonols and genes related to flavonol biosynthesis during PACC in L. filicaulis. The functions of flavonol synthase（FLS）genes were validated through prokaryotic enzyme activity assays and transgenic experiments in tobacco. Additionally，transient protoplast transfection assays were employed to investigate the regulatory mechanisms by which MYB transcription factors control FLS expression. The results revealed that flavonols and anthocyanins accumulate synchronously during PACC in L. filicaulis，with total flavonols significantly increased in the red flowers. Two FLS genes，LfFLS1 and LfFLS2，exhibited differential expression patterns：LfFLS1 was highly expressed in yellow flowers，whereas LfFLS2 was specifically upregulated in red flowers. Moreover，both LfFLS proteins displayed catalytic activity but showed distinct substrate preference：LfFLS1 exclusively utilized dihydrokaempferol（DHK）and dihydroquercetin（DHQ），while LfFLS2 efficiently catalyzed all three types of dihydroflavonols. Additionally，LfFLS1 was co-activated by subgroup 7 MYB transcription factor LfMYB12 and subgroup 19 MYB transcription factor LfMYB21，whereas LfFLS2 was exclusively regulated by LfMYB21. This differential expression pattern aligns with the metabolic demands of distinct PACC stages，highlighting a sophisticated regulatory network that modulates flavonol metabolism to support adaptive color transitions.

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Cultivation · Physiology & Biochemistry

• Effect of Fruit Bag Color on Fruit Quality in‘Harlikar’Apples
• ZHOU Jiaxu, LI Hongjian, ZHANG Xiumei, LI Chenghui, LIU Ying, YU Nianwen
• Acta Horticulturae Sinica. 2026, 53(5): 1395-1408. DOI:10.16420/j.issn.0513-353x.2025-0466
• Abstract ( 31 ) HTML ( 15 ) PDF (1555KB) ( 15 ) 　　　

• This study aimed to investigate the multidimensional effects of fruit bag color on apple quality characteristics，clarify the roles of different colored bags in regulating fruit appearance，texture，nutritional composition，flavor，and aroma profiles，and provide theoretical support for optimizing fruit bagging techniques. Using 6-year-old‘Harlikar/Malus hupehensis’trees as test materials，seven bagging treatments were applied：white-green double-layer bags，orange bags，yellow bags，green bags，blue bags，brown-black double-layer bags and brown-red double-layer bags（control）. Fifty-two parameters were measured，including appearance characteristics（single fruit weight，fruit shape index and color），texture Parameters（firmness，elasticity，etc.），nutritional quality（soluble sugars，vitamin C，mineral elements，etc.），and flavor profiles（electronic nose and electronic tongue sensory systems for the analysis of aroma compound types and flavor.）. The comprehensive evaluation incorporated with differential analysisand principal component analysis（PCA）. The results indicated that in terms of appearance，fruit weight under blue bagging was significantly the highest，but the number of fruit dots was higher；The fruit peel brightness under the brown-red double-layer bag and brown-black double-layer bag treatments was significantly higher than other treatments，while the green bag resulted in the most yellow peel. In terms of texture and quality，the green bag treatment showed the highest soluble sugar，VC，and total phenol contents，along with a significant increase in fruit firmness. The blue bags enhanced the content of soluble solids，soluble protein，and solid/acid ratio with the yellow bag significantly boosting mineral elements such as N，K，Ca，and Fe. The blue bag improved flesh elasticity. In terms to flavor ，electronic tongue analysis revealed that the fruit was primarily sweet and umami，with overall weak sourness. The sweet taste response was highest with the blue and yellow bags，while the umami response peaked with the brown-red double-layer bag and was lowest with the orange bag. The brown-black double-layer bag enhanced fruit flavor，and the blue bag reduced astringency. Electronic nose analysis indicated that the fruit aroma mainly derived from sulfides，terpenes，and aromatic components，with the green and yellow bags significantly increasing the contents of these three substances. In conclusion，The green bag treatment achieved the highest comprehensive score，exhibiting optimal performance in aroma，nutrition，and texture，followed by the brown-black double-layer bag.

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• Influence of Cold Stress and Cold Resistance Evaluation on the Seedling Stage of Peach Cultivars
• LI Jie, TIAN Qihang, LIU Guojian, TIAN Zhendong, WANG Yu, WANG Zhaoyuan, CHANG Ruifeng, LI Yonghong
• Acta Horticulturae Sinica. 2026, 53(5): 1409-1424. DOI:10.16420/j.issn.0513-353x.2025-0142
• Abstract ( 29 ) HTML ( 15 ) PDF (4349KB) ( 15 ) 　　　

• The low-temperature environment was simulated in artificial climate chamber at 0 ℃，-15 ℃，-20 ℃，-25 ℃ and-30 ℃. The stems of 21 one-year old peach cultivars were selected. The differences in relative conductivity，tissue browning rate，activity of phenylalanine ammonia-lyase（PAL）and contents of malondialdehyde（MDA），free proline（Pro）and soluble sugar（SS）were analyzed. The cold resistance and physiological indexes of different peach cultivars were evaluated by the membership function method and principal component analysis. The results indicated that the relative conductivity，tissue browning rate，activity of PAL，contents of MDA and Pro in stems of 21 peach cultivars increased with the decrease of temperature，while SS content increased firstly and then decreased. Compared with the control，relative conductivity and activity of PAL in trunks of Jinhuangjin，21 Century and Zhonghua Shoutao increased greatly，contents of Pro in trunks of Hangongzhu，Donghe 1 and Hunchun increased greatly. The cold resistance of 21 cultivars were in the decreasing order of Donghe 1，Hunchun，Hangongzhu，Beijing Wanmi，Jinbao，Qiuyue，Qiuyan，Xiahui 6，Qiuyi，Cuibao，Zhongyou 8，Chunxue，Zhongyou 21，Xiufeng，Okubo，Yantehong，Jinhuangjin，Zhongyoupan 7，Jinao，21 Century，Zhonghua Shoutao. According to the comprehensive evaluation by membership function method，the classification of cold resistance type（grade）was consistent with the semi-lethal temperature（LT₅₀）and the field survey results. The main indexes that affect the cold resistance of peach trees at the seedling stage are xylem thickness，xylem ratio，tissue browning rate，relative conductivity，activity of PAL and contents of MDA，free Pro and SS，and the differences（content）of these indexes can be used as important indexes to evaluate the cold resistance.

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• Effect of Chitin Induction on Postharvest Sweet Cherry Fruit Against Black Spot and Storage Quality
• CUI Jianchao, JIA Xiaohui, LI Litao, FAN Liying, ZHAO Wenshi, CHEN Long, WANG Xumin, HE Limin, XU Haijiao
• Acta Horticulturae Sinica. 2026, 53(5): 1425-1438. DOI:10.16420/j.issn.0513-353x.2025-0261
• Abstract ( 22 ) HTML ( 6 ) PDF (2470KB) ( 6 ) 　　　

• The effects of different concentrations of chitin on the mycelia growth and spore germination of Alternaria alternata，the causal agent of black spot disease in sweet cherry，were investigated under in vitro conditions. Meanwhile，‘Shamidou’sweet cherry fruits were used as experimental material and treatment with chitin，then A.alternata spore suspension were inoculated，which to explore the efficacy and mechanism of chitin-induced resistance against black spot disease. The results showed that low concentrations of chitin（0-0.01% for colony diameter and 0-0.001% for spore germination）had no significant inhibitory effect on A. alternata. In vivo experiments demonstrated that chitin at concentrations ranging from 0.01% to 1% significantly suppressed the expansion of black spot on sweet cherry fruit，with 0.5% and 1% identified as the optimal concentrations and 24 h as the most effective induction time. Chitin treatment also effectively controlled black spot disease during low-temperature storage，reduced natural decay in postharvest sweet cherry，and had no adverse effects on fruit quality. Furthermore，chitin treatment enhanced the up-regulated expression of defense-related enzyme genes（PaCAT，PaSOD，PaPOD，PaPPO）as well as SA/JA signaling pathway genes，such as PaNPR1-like and PaOPR3. Correspondingly， the activities of defense-related enzymes， including superoxide dismutase（SOD）， catalase（CAT）， peroxidase（POD）， polyphenol oxidase（PPO），chitinase（CHI）and β-1，3-glucanase（GLU），were increased in fruit. Therefore，chitin-induced resistance against black spot disease in sweet cherry fruit is associated with enhanced activities of defense-related enzymes and up-regulation of their corresponding genes.

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• Fruit Development and Changes in Main Quality and Aroma Components of‘Guifei’Kiwifruit
• LIU Ruonan, YE Kaiyu, GAO Jianyou, LI Jiewei, ZHANG Meijuan, GONG Hongjuan, ZHU Rongxiang, XIA Liming, ZHA Manrong, LIU Shibiao, WANG Faming, LIU Cuixia
• Acta Horticulturae Sinica. 2026, 53(5): 1439-1456. DOI:10.16420/j.issn.0513-353x.2025-0206
• Abstract ( 13 ) HTML ( 6 ) PDF (2495KB) ( 6 ) 　　　

• Using‘Guifei’kiwifruit as the research subject，this study systematically observed the dynamic changes in the fruit shape parameters，single fruit weight，dry matter，vitamin C，total sugar，total acid，sugar-acid ratio and volatile compounds during its development. The aim was to explore the dynamic changes in fruit quality during the development of‘Guifei’kiwifruit and provide a basis for scientific cultivation management and determination of the optimal harvest period. The results showed that during the fruit development of‘Guifei’kiwifruit，the transverse，longitudinal，and lateral diameters exhibited a single“S”curve change，while the single fruit weight displayed a double“S”curve change. The first rapid growth period occurred within 56 days after flowering，during which the fruit expanded rapidly. The second rapid growth period occurred from 84 to 112 days after anthesis（DAA），during which fruit weight and dry matter content increased significantly. The dry matter content of mature fruit reached 18.69%. Vitamin C content displayed a rise-fall-rise trend，peaking at 2.45 g · kg^-1 at 140 DAA. Similarly，total sugar content exhibited a rise-fall-rise trend，rising to 7.52% at maturity. Total acid content initially increased and then declined，decreased to 0.99% at 140 DAA. The sugar-acid ratio showed a fall-rise-fall-rise trend，and dropped to a minimum of 3.98 at 112 DAA，and increased to 7.66 at maturity. A total of 59 aroma compounds were detected in‘Guifei’kiwifruit. During post-harvest ripening，the total aroma content increased significantly and then decreased，peaking at 1 162.53 μg · kg^-1 after 4 days after harvest（DAH）with a shift from aldehydes to esters（aldehydes accounted for 83.08% after 2 days of ripening，while esters accounted for 76.15% after 4 days of ripening）. Twenty-one key aroma components were identified as direct contributors，with ethyl 2-methylbutyrate，1-octen-3-one and ethyl butyrate being the main components. During fruit development and the first 0-2 days of post-harvest ripening，fatty and grassy aromas predominated，while fruity aromas increased significantly after 4 DAH. In summary，140 DAA is considered the optimal harvest period. During the first rapid growth stage，combined application of nitrogen，phosphorus，and potassium fertilizers is recommended，while during the second rapid growth period，attention should be given to phosphorus and potassium fertilizer application. The increase in esters can serve as an indicator of‘Guifei’fruit maturity. The fruit exhibits the strongest fruity aroma after 4 days of post-harvest ripening，making it the optimal consumption period.

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• Estimation Model of Leaf Moisture Content in Walnut Canopy Based on Hyperspectral Technology
• XIA Qiuhao, MA Zhihao, LUO Langqin, CHEN Tiancai, JIN Qiang, WANG Hongxia, ZHANG Rui, GUO Zhongzhong
• Acta Horticulturae Sinica. 2026, 53(5): 1457-1476. DOI:10.16420/j.issn.0513-353x.2025-0190
• Abstract ( 22 ) HTML ( 7 ) PDF (7439KB) ( 7 ) 　　　

• To achieve rapid，accurate，and non-destructive monitoring of canopy leaf water content in walnut orchards under different water treatments，an exploration was conducted into a non-destructive detection method for walnut leaf water content based on hyperspectral technology. Using‘Wen 185’walnuts as the experimental subject，the spectral data and leaf water content of the walnut canopy were measured. The raw spectral data were processed using first derivative（FD），detrending（Detrend），convolution smoothing + first derivative（SG + FD），first derivative + standard normal variate（FD + SNV），and standard normal variate + detrending（SNV + Detrend）. Feature band combinations were screened through the discrete binary particle swarm optimization（BPSO），successive projections algorithm（SPA），uninformative variable elimination（UVE），and competitive adaptive reweighted sampling（CARS）methods. Random forest（RF）and extreme learning machine（ELM）models were constructed to compare and select the optimal non-destructive detection model for walnut leaf water content. By establishing inversion models with different feature band combinations，the prediction model developed using the FD-CARS-ELM method outperformed the RF model，with training set R² = 0.909，RMSE = 1.515，RPD = 3.323；test set R² = 0.813，RMSE = 1.675，RPD = 2.328.

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• Effects of SA-OPDA Crosstalk on the Antioxidant System of Striped Leaves in Sinobambusa tootsik f. albostriata
• TANG Yu, ZENG Meiyin, ZHU Pengkai, HE Tianyou, ZHENG Yushan, CHEN Lingyan
• Acta Horticulturae Sinica. 2026, 53(5): 1477-1490. DOI:10.16420/j.issn.0513-353x.2025-0135
• Abstract ( 16 ) HTML ( 3 ) PDF (1035KB) ( 3 ) 　　　

• To elucidate the roles of exogenous salicylic acid（SA）and 12-oxo-phytodienoic acid （OPDA）in regulating the antioxidant mechanisms of variegated plants，leaves of different phenotypes of Sinobambusa tootsik f. albostriata were treated with various concentrations of SA，OPDA，and SA + OPDA. The contents of malondialdehyde（MDA），superoxide anion（$\mathrm{O}_2^{\bar{.}}$），as well as the activities of antioxidant enzymes including superoxide dismutase（SOD），peroxidase（POD），catalase（CAT），and antioxidant enzymes involved in the ascorbate-glutathione（AsA-GSH）cycle，were determined. The results showed that treatments with 0.5 mmol · L^-1 SA，30 μmol · L^-1 OPDA，or 0.5 mmol · L^-1 SA + 30 μmol · L^-1 OPDA significantly enhanced the activities of SOD，POD，CAT，and AsA–GSH cycle enzymes in all leaf phenotypes，markedly increased glutathione（GSH）levels，and effectively scavenged the accumulated reactive oxygen species（ROS）. Comparisons among phenotypes further revealed that GSH content in variegated leaves was significantly higher than in fully white or fully green leaves，and that the white sectors of variegated leaves exhibited stronger antioxidant characteristics than the green sectors. This suggests that variegated leaves possess differentiated redox homeostasis during the formation of color sectors，and that the white tissues may elevate non-enzymatic antioxidant capacity to compensate for the oxidative pressure caused by the absence of chloroplasts，thereby contributing to the stability of the variegated pattern. Overall，SA primarily enhances basal cellular antioxidant capacity by rapidly activating antioxidant enzymes and reinforcing the AsA–GSH cycle，whereas OPDA，as an oxylipin signal，tends to modulate lipid peroxidation and stress-responsive pathways. The two signals act in a complementary manner，and their combined application more effectively reduces ROS accumulation，thereby promoting the phenotypic stability of variegated leaves.

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Plant Protection

• Identification and Biological Characteristics of Pathogens Causing Canker Disease of Malus sieversii
• ZHANG Qin, XIA Hongfei, SHAN Lei, WUSIMAN · Saimi, ZHANG Xuechao, WANG Lili
• Acta Horticulturae Sinica. 2026, 53(5): 1491-1501. DOI:10.16420/j.issn.0513-353x.2025-0198
• Abstract ( 13 ) HTML ( 7 ) PDF (3047KB) ( 7 ) 　　　

• This experiment was conducted to isolate，pathogenicity determination，morphological characteristics，phylogenetic analysis of ITS，TEF，ACT and TUB sequences and identification of the biological characteristics of canker disease of Malus sieversii. The results showed that a total of six pathogens were identified：Cytospora ambiens，C. hoffmannii，C. mali，C. pruinopsis，C. leucostoma and C. parasitica，all belonging to the genus Cytospora. The biological characteristics results indicated that the optimal culture conditions for mycelial growth of the six strains were on PDA medium，at 25-30 ℃，and pH 6-8. C. pruinopsis utilized sucrose as the optimal carbon source，while glucose was the optimal carbon source for the other strains. The optimal light conditions for the mycelial growth of different Cytospora species were determined as follows：C. ambiens and C. mali exhibited the best growth under full light；C. pruinopsis grew optimally under a 12-hour light-dark cycle；C. parasitica thrived in complete darkness；C. leucostoma showed the most favorable growth under both full light and a 12-hour light-dark cycle；and C. hoffmannii could grow well under all tested light conditions. In this study，C. parasitica was identified as the principal pathogenic fungus causing canker disease in Malus sieversii，with the highest isolation frequency of 63.87%；C. ambiens and C. hoffmannii were newly identified pathogens on Malus sieversii.

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• Identification of Black Spot Pathogen in Cabbage，Analysis of Biological Characteristics，and Screening of Resistant Germplasm Resources
• WANG Caihong, ZHANG Yangyong, LI Sen, ZHANG Chaowen, KONG Xiaoping, LÜ Honghao, WANG Yong, YANG Limei, JI Jialei, ZHUANG Mu
• Acta Horticulturae Sinica. 2026, 53(5): 1502-1520. DOI:10.16420/j.issn.0513-353x.2025-0509
• Abstract ( 16 ) HTML ( 13 ) PDF (9698KB) ( 13 ) 　　　

• Black spot disease is one of the major constraints in cabbage production. Multiple black spot disease samples were collected from five major cabbage production regions Beijing，Chongqing，Hubei，Sichuan，and Inner Mongolia. After isolation and purification，30 strains of the pathogen were obtained. Morphological characteristics of the colonies，conidia，and conidial chains of the pathogen were observed and described. Pathogenicity tests conducted using mycelial plug inoculation identified the BJA1 strain from Beijing as the most virulent. Molecular identification through cloning and phylogenetic analysis of the ITS，TEF1，and GAPDH genes confirmed that BJA1 is a typical strain of Alternaria brassicicola. Using this strain，an efficient and stable in vitro inoculation system for evaluating resistance to cabbage black spot disease was established. The optimal spore concentration for inoculation was determined to be 1 × 10⁵ spores · mL^-1，and the ideal plant growth stage for inoculation was the four-leaf stage. This system was applied to evaluate the resistance of 100 cabbage germplasms to black spot disease，leading to the identification of 24 moderately resistant accessions and one resistant accession with a disease index of 25.93.

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• Screening of Biocontrol Bacteria Against Fusarium Wilt in Watermelon and Study on Their Biocontrol Mechanisms
• YANG Jiani, MA Qiaonü, GU Xin, JIANG Tong, SU Xiaofen
• Acta Horticulturae Sinica. 2026, 53(5): 1521-1534. DOI:10.16420/j.issn.0513-353x.2025-0286
• Abstract ( 28 ) HTML ( 7 ) PDF (1933KB) ( 7 ) 　　　

• Fusarium wilt of watermelon，caused by Fusarium oxysporum f. sp. niveum（FON），significantly reduces crop yield and quality. This study isolated two antagonistic bacteria. Bacillus subtilis PJ3 and Bacillus atrophaeus HY5，from soil using a dual-culture assay. Their fermentation broths disrupted FON conidia，damaged cell membranes by reducing ergosterol and protein content，and inhibited fungal growth. Pot trials confirmed their biocontrol efficacy，with PJ3，HY5，and their consortium significantly reducing disease incidence and severity. The consortium showed the best control，reducing disease severity by 71.43%，outperforming single strains. In summary，PJ3 and HY5 exhibit good biocontrol potential against watermelon Fusarium wilt，and their combined application yields the best results.

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Reviews

• Research Progress on the Mechanism and Application of Brassinosteroid in Regulating Plant Height
• LÜ Xinyang, GUO Yue, FENG Minghan, ZHU Pengfang, FENG Xin
• Acta Horticulturae Sinica. 2026, 53(5): 1535-1552. DOI:10.16420/j.issn.0513-353x.2025-0519
• Abstract ( 21 ) HTML ( 14 ) PDF (768KB) ( 14 ) 　　　

• Plant height is a key trait that determines plant architecture，lodging resistance，and yield. Brassinosteroid（BR）plays a crucial role in regulating plant height. This review summarizes recent advances in understanding how BR regulates plant height. At the physiological level，BR modulates cell elongation and division by affecting water uptake，cell wall modification，and microtubule stability. At the molecular level，BR precisely controls plant height through key biosynthesis genes such as DWF4，CPD，DET2，ROT3，CYP90D1，and CYP85A1/2，as well as signal transduction genes including BRI1，BAK1，BSU1，BIN2，BZR1，and BES1. During their functioning，BR crosstalks with gibberellin，auxin，jasmonate，abscisic acid，ethylene，and strigolactone，forming a complex regulatory network for plant height. The application of BR in dwarf breeding is also discussed，BR-related dwarf germplasm demonstrates significant potential in improving plant architecture and increasing yield. Finally，the problems existing in the current research are analyzed and prospects are put forward. The key research directions highlighted in this review will provide a a reference for the in-depth study on the regulatory mechanism of plant height and the practice of dwarf breeding.

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• Advances in Functional Genomics of Brassicaceae Vegetables
• SUN Yumeng, WANG Dong, YANG Lei, MA Wei, SHEN Shuxing, ZHAO Jianjun
• Acta Horticulturae Sinica. 2026, 53(5): 1553-1570. DOI:10.16420/j.issn.0513-353x.2025-0353
• Abstract ( 27 ) HTML ( 16 ) PDF (1095KB) ( 16 ) 　　　

• Brassicaceae vegetables，such as Chinese cabbage，Cabbage，mustard，and radish，serve as globally significant economic crops，playing an indispensable role in nutritional health，agricultural economies，and ecological balance. However，challenges including their complex genomic architecture （e.g.，polyploidy，abundant repetitive sequences，and gene redundancy）and low genetic transformation efficiency have hindered the elucidation of regulatory mechanisms for critical agronomic traits and their application in molecular breeding. In recent years，rapid advancements in functional genomics have provided abundant genetic resources and theoretical foundations for the targeted improvement and efficient integration of superior traits in Brassicaceae vegetables，such as high yield，stress tolerance，disease resistance，and enhanced functional nutrition quality. This review systematically summarizes major progress in functional genomics research on Brassicaceae vegetables，analyzes the severe challenges currently faced，identifies critical challenges including low genome assembly accuracy，difficulties in multi-omics data integration，and limited gene editing efficiency，and discusses the immense application prospects of the development of optimized technologies-such as third-generation sequencing，single-cell omics，and CRISPR-Cas systems-in accelerating the development of novel cultivars with improved stress resilience，productivity，and functional nutritional profiles.

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