Genetic & Breeding·Germplasm Resources·Molecular Biology

• Cloning and Functional Analysis of FaGH3.17 Gene in Strawberry
• YANG Juanbo, GUO Lili, LU Shixiong, GOU Huimin, WANG Shuaiting, ZENG Baozhen, MAO Juan
• Acta Horticulturae Sinica. 2024, 51(11): 2483-2494. DOI:10.16420/j.issn.0513-353x.2023-1008
• Abstract ( 362 ) HTML ( 278 ) PDF (2258KB) ( 278 ) 　　　

• In order to study the response of GH3.17 gene to salt stress in strawberry，the evolutionary relationship and physicochemical properties of FaGH3.17 were analysed using bioinformatics，and the gene was cloned and subsequently subcellularly localised in tobacco and heterologously overexpressed in Arabidopsis to verify its function in salt stress. The results showed that FaGH3.17 is an acidic and unstable hydrophobic，non-secretory protein，and the analysis of the evolutionary relationship of species revealed that FaGH3.17 is the closest relative to Potentilla anserina. Subcellular localisation in tobacco revealed that FaGH3.17 was mainly localised in the nucleus and cell membrane. Heterologously overexpression analysis in Arabidopsis thaliana revealed that under salt stress，the conductivity，MDA and H₂O₂ content were higher than those of wild-type plants，which were elevated by 15.43%，42.97%，and 18.86%，respectively，whereas the Pro content，POD，SOD，and CAT activities were significantly lower than those of the wild-type plants，which were reduced by 13.28%，15.42%，14.22%，19.87%，respectively. And the relative expression of salt-responsive genes were all significantly reduced. It was shown that heterologous overexpression of FaGH3.17 significantly reduced the antioxidant enzyme activities and osmoregulatory substance contents in Arabidopsis，which predicts that GH3.17 may attenuate the salt tolerance of plants.

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• SSR Marker Association Analysis and Fingerprint Construction of Main Traits of Plum Fruit
• YUE Linqing, WU Yichao, HE Xingxing, XIANG Mingyan, WANG Jin, WU Zheng, ZHU Shiguo, DING Mengqi, ZHANG Jian, FANG Xiaomei, YI Zelin
• Acta Horticulturae Sinica. 2024, 51(11): 2495-2509. DOI:10.16420/j.issn.0513-353x.2023-0988
• Abstract ( 164 ) HTML ( 125 ) PDF (2911KB) ( 125 ) 　　　

• A study on eleven fruit features generated from 102 plum resources was carried out in 2022 and 2023. The coefficient of variation for fruit weight was the highest，while edible ratio and fruit shape indices had lower coefficients. A total of 405 allelic variants were amplified in the test material using 78 pairs of polymorphic primers，with polymorphism information content（PIC）ranging from 0.06 to 0.80 and a mean value of 0.53. An association analysis revealed that 55 SSR markers had highly significant associations with 11 major traits，explaining 4.01%-14.76% of the phenotypic variance. Among the test materials，29 exhibited two or more highly significant associations with traits in two years under GLM and MLM models. From 78 primers，27 pairs of primers were selected to distinguish 102 materials，and the fingerprints of 102 plum resources were constructed.

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• Development and Application of Prunus salicina InDel Markers Based on Genome Re-sequencing
• CHEN Fangce, HU Pingzheng, XIE Weiwei, WANG Zhengpeng, ZHONG Chuangnan, LI Haiyan, HE Yehua, PENG Ze, WAN Baoxiong, LIU Chaoyang
• Acta Horticulturae Sinica. 2024, 51(11): 2510-2522. DOI:10.16420/j.issn.0513-353x.2024-0066
• Abstract ( 169 ) HTML ( 103 ) PDF (1775KB) ( 103 ) 　　　

• Based on the genome re-sequencing results of several Chinese plum（Prunus salicina）germplasm resources，a series of candidate indel loci were mined，and 53 InDel markers which were distributed on different chromosomes and exhibited stable polymorphism，were screened out. The genetic diversity of 79 plum germplasm resources was evaluated by using 53 InDel markers. The average frequency of major alleles was 0.6593，the genetic diversity index（H_s）was 0.4304，and the polymorphism information content（PIC）was 0.3489. Among them，45 markers had high polymorphism information content（PIC > 0.25）. Based on UPGMA cluster analysis，79 accessions were divided into 2 groups and 10 subgroups with genetic similarity coefficients of 0.623 and 0.666，respectively. The classification results were related to the geographical distribution of germplasm resources. The plum germplasms were distinguished by 13 InDel markers，and the germplasm specific molecular identity cards were constructed. By selecting InDel markers with polymorphism among parents，the F₁ hybrid authenticity of positive and negative cross combinations of two plum cultivars in South China was identified.

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• Functional Study of AP2/ERF in Response to Black Rot at Broccoli Seedling Stage
• TANG Zheng, CHEN Sique, XU Qian, ZHONG Weijie, LIU Qing, ZHU Shiyang
• Acta Horticulturae Sinica. 2024, 51(11): 2523-2539. DOI:10.16420/j.issn.0513-353x.2023-0469
• Abstract ( 136 ) HTML ( 85 ) PDF (4339KB) ( 85 ) 　　　

• To explore the response mechanism of black rot and identify disease-resistance related genes through RNA-Seq analysis of broccoli（Brassica oleracea L. var. italica）leaves infected by black rot pathogen. Gene Ontology（GO）analysis showed that up-regulated differentially expressed genes（DEGs）were significantly enriched in stress response and phytohormone signaling pathways after 3，5，and 7 days infected by pathogens compared to uninoculated. At these three time points，the up-regulated genes in overlapped DEGs encoded up to 32 AP2/ERF transcription factors. Their encoded protein sequence ranged from 132 to 344 amino acids in length，and its promoter contained a large number of cis-elements in response to abscisic acid，auxin，jasmonic acid，gibberellin and salicylic acid（SA）. SA treatment significantly enhanced the resistance of broccoli to black rot，and strongly induced the expression of AP2/ERF and defense-related genes. BolC1t04894H encodes an EAR type transcriptional suppressor ERF4，which is localized in the nucleus. Transient expression of broccoli ERF4 resulted in sensitivity of tobacco leaves to Xcc treatment. Electrophoretic Mobility Shift Assay（EMSA）result indicated that ERF4 could bind the GCC-box sequence in the promoter of WRKY33. Subsequently，double luciferase reporter system experiments showed that ERF4 inhibited WRKY33 expression. Taken together，the phytohormone signalling pathway are activated in broccoli after black rot pathogen infection，and SA strongly induces the AP2/ERF expression，thereby regulating a series of defense-related genes transcription to response black rot.

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• Genetic Diversity of Ralstonia solanacearum Strains Isolated from Fujian Province and Evaluation of Tomato Rootstocks for Resistance to Bacterial Wilt
• WANG Rongbo, WANG Haiyun, ZHANG Qianrong, CAI Songling, LI Benjin, ZHANG Meixiang, LIU Peiqing
• Acta Horticulturae Sinica. 2024, 51(11): 2540-2554. DOI:10.16420/j.issn.0513-353x.2024-0395
• Abstract ( 177 ) HTML ( 52 ) PDF (2827KB) ( 52 ) 　　　

• In this study，62 strains of Ralstonia solanacearum were isolated in 2021 to 2022 from five tomato-growing areas in Fujian，China. Using phylotype-specific multiplex PCR（Pmx-PCR），the biochemical and race tests，all strains were identified as phylotype I and race 1. Of these，61 strains were identified as belonging to biovar Ⅲ，while one strain was classified as atypical biovar. The strains were further divided five different sequevars（14，15，16，17，and 34）based on polymorphisms in the endoglucanase（egl）gene. Among the five sequevars，sequevar 15 was the predominant type in Fujian Province. In addition，the resistance of 13 tomato rootstock cultivars to R. solanacearum was evaluated，revealing significant differences in resistance among the cultivars to different sequence types of the pathogen. It is noteworthy that two rootstock cultivars，‘Guizhen 1’and‘Weier Shengen’，exhibited broad-spectrum resistance to the predominant strains in Fujian Province.

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• Construction of Tomato Leaf Curl New Delhi Virus Infectious Clone and Its Application in Evaluation for Melon Disease Resistance
• LIU Liming, GENG Yanfei, HAO Fangmin, KANG Baoshan, WU Huijie, GU Qinsheng
• Acta Horticulturae Sinica. 2024, 51(11): 2555-2564. DOI:10.16420/j.issn.0513-353x.2023-0733
• Abstract ( 139 ) HTML ( 66 ) PDF (3123KB) ( 66 ) 　　　

• In this study，a tomato leaf curl New Delhi virus（ToLCNDV）melon isolate Haimen 6 （HM6）was used as template to obtain its infectious clone by tandem repeat fragment method，and its infectivity was examined in different crops. Meanwhile，the resistance of 25 Cucumis melo cultivars were evaluated. The results showed that whatever infectious clones containing 1.57-mer DNA-A tandem repeat （1.57A）and 1.43-mer DNA-B tandem repeat（1.43B），respectively，were co-infiltrated or the clone containing both 1.57A and 1.43B was directly inoculated with melon，and the infection rate of the plants could reach 100%. Infectious clones containing 1.57A and 1.43B，respectively，were co-infiltrated into other crops，and it was found that it could infect Nicotiana benthamiana，Solanum lycopersicum，Cucurbita moschata，Cucurbita pepo，Lagenaria siceraria，Cucumis sativus，and Luffa aegyptiaca，but could not infect Citrullus lanatus. Through resistance evaluation，it was found that 3 of the 25 tested melon materials showed resistance，3 materials showed susceptibility and 19 materials showed high susceptibility.

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• Preliminary Analysis and Selection of Parental Combining Ability of Hybrid Progenies of Betula pendula‘Purple Rain’
• ZHANG Jie, WEN Haoyu, MA Lixin, ZHU Qingchao, LIU Long, JIANG Jing, and LIU Guifeng
• Acta Horticulturae Sinica. 2024, 51(11): 2565-2574. DOI:10.16420/j.issn.0513-353x.2023-0665
• Abstract ( 69 ) HTML ( 36 ) PDF (800KB) ( 36 ) 　　　

• This study focused on the hybrid progeny of Betula pendula‘Purple Rain’from 20 five-year-old hybrid combinations，measuring traits such as growth，leaf color，and survival rate. The combining ability and effect values of these traits were analyzed using WinNCⅡsoftware. A comprehensive evaluation of the traits was conducted by applying the membership function method in conjunction with principal component analysis，leading to the selection of superior parents and hybrid combinations. Variance analysis revealed that traits such as ground diameter，leaf color，and survival rate showed significant（P < 0.05）or highly significant（P < 0.01）differences among the progeny families of different hybrid combinations. Variance analysis of combining ability effect values indicated that the variance of general combining ability（GCA）effect values for maternal traits was significant or highly significant，while only the variance of the paternal trait effect value for leaf color saturation（a^*）was highly significant. The GCA analysis suggested that the additive effects of the maternal parent were generally greater than those of the paternal parent，with variance components ranging from 0.94% to 84.16%. The analysis of specific combining ability（SCA）effects showed that SCA had the strongest influence on a^*，accounting for 82.30%. Based on the combining ability effect values for growth，leaf color，and survival rate traits in the hybrid progeny，M5 and M1-34 were selected as superior paternal parents，S3 as a superior maternal parent，and SZ-4 × M1 and S3 × M5 as superior hybrid combinations.

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Cultivation·Physiology & Biochemistry

• Correlation Analysis of Fruit Quality and the Nutrient Level in Plant and Soil of Wine Grape‘Merlot’
• WANG Xiaolong, SHAO Xuedong, ZHANG Zhengwen, ZHONG Xiaomin, LIU Chang, WANG Zhiqiang, WANG Baoliang, JI Xiaohao, SHI Xiangbin, WANG Haibo
• Acta Horticulturae Sinica. 2024, 51(11): 2575-2593. DOI:10.16420/j.issn.0513-353x.2023-0563
• Abstract ( 154 ) HTML ( 67 ) PDF (2559KB) ( 67 ) 　　　

• The aim is to lay a foundation for improving the quality of Merlot fruit and guiding precise fertilization in orchards. Taking Merlot grapewine in Yantai，Shandong Province as the test material，combined with the“5416”formula fertilization program from 2019 to 2021，principal component analysis （PCA）was used to evaluate 14 quality indexes of fruit at maturity stage，including 100 grain mass，soluble solid matter，ratio of skin to fruit，ratio of seed to seed，number of grains，total phenols，anthocyanins in peel，total flavonoids in peel and seed，flavanols in peel and seed，and tannins in peel and seed. PCA results show that T11 treatment（N 124.5 kg · hm^-2，P₂O₅ 46.5 kg · hm^-2，K₂O 0 kg · hm^-2，CaO 56.3 kg · hm^-2 and MgO 69.8 kg · hm^-2）had obvious effect on improving the comprehensive quality of Merlot grapewine. Correlation analysis was used to determine N in germination stage，P in maturation stage，K in maturation stage，Ca in maturation stage and Mg in germination stage distributed in 0-40 cm as soil nutrient diagnostic factors for anthocyanins. Plant nutritional diagnostic factors for anthocyanins were determined：N of petiole at veraison stage，P of inflorescence at full-bloom stage，K of leaf at full-bloom stage，Ca of leaf at veraison stage，Mg of petiole at maturity stage，Fe and Mn of leaf at veraison stage，Cu of fruit at maturity stage，Zn and B of inflorescence at full-bloom and Mo of leaf at full-bloom stage. The function model of diagnostic factors and anthocyanins was established by the method of component nutrition diagnosis（CND），and the diagnostic criteria for soil and plant nutrition of high-anthocyanin vineyards（high-quality vineyards）were finally established：The normalized value of anthocyanins corresponding to cumulative variance of soil element content > 0.6372；The normalized value of anthocyanins corresponding to the cumulative variance of plant medium and large elements content was > 0.8353；The normalized value of anthocyanin corresponding to cumulative variance of trace element content was > 0.8699. The diagnostic criteria for soil nutrition were N 0.06-0.21 mg · g^-1，P 0.08-1.17 mg · g^-1，K 0.05-0.23 mg · g^-1，Ca 0.52-8.51 mg · g^-1 and Mg 0.04-0.65 mg · g^-1. The diagnostic criteria of plant nutrition were N 5.38-11.00 mg · g^-1，P 5.45-10.88 mg · g^-1，K 6.73-39.75 mg · g^-1，Ca 35.57-68.83 mg · g^-1，Mg 9.30-24.63 mg · g^-1，Fe 233.93-398.83 mg · kg^-1，Mn 292.55-520.30 mg · kg^-1，Zn 29.03-73.65 mg · kg^-1，Cu 18.22-28.93 mg · kg^-1，B 20.52-35.13 mg · kg^-1 and Mo 0.78-1.85 mg · kg^-1. According to the abundance and deficiency characteristics of plants and soil elements in low quality vineyard（the normalized value of anthocyanins corresponding to the cumulative variance of the content of large and medium elements in the low-quality vineyards of Melot grapewine was < 0.8353；the normalized value of anthocyanin corresponding to the cumulative variance of soil elements was < 0.6372），it is recommended to apply P fertilizer to soil in a small amount and multiple times. Improve the water and fertilizer management system to improve the absorption capacity of K and Ca elements. The deficient trace elements are properly supplemented by foliar spraying.

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• Effect of Melatonin on Antioxidant System of Tomato Senescent Leaves
• WANG Yanan, LIU Xutao, JING Tongtong, CHAI Yating, ZHANG Xiaowei, AI Xizhen, BI Huangai
• Acta Horticulturae Sinica. 2024, 51(11): 2594-2606. DOI:10.16420/j.issn.0513-353x.2023-0964
• Abstract ( 194 ) HTML ( 92 ) PDF (2457KB) ( 92 ) 　　　

• To explore the regulation mechanism of exogenous melatonin（MT）on leaf senescence of tomato（Solanum lycopersicum L.）,‘Jinpeng 1'tomato and SlTDC（L-tryptophan decarboxylase encoding gene，a key gene for MT synthesis）overexpression and knockout transgenic tomato plants were used as experimental materials and dark condition was used to simulate senescence，the effects of MT on senescence-related gene（SAG12）expression,reactive oxygen species（ROS）accumulation and antioxidant system were studied in this paper. The results showed that the mRNA abundance of SAG12，the accumulation of hydrogen peroxide（H₂O₂）and superoxide anion superoxide anion，the activities of superoxide dismutase（SOD），peroxidase（POD）and ascorbate peroxidase（APX）and their gene expression，and the content of ascorbic acid（AsA）and glutathione（GSH）in tomato leaves increased significantly with the prolongation of dark treatment time. Compared with the control（H₂O），the tomato treated with exogenous MT showed lower SAG12 mRNA abundance，the content of H₂O₂ and superoxide anion and higher activities of SOD，POD，APX as well as their gene expression and the content of redox substances. Meanwhile，overexpression of SlTDC also significantly down-regulated the mRNA abundance of SAG12 and the content of H₂O₂ and superoxide anion，and enhanced antioxidant capacity，while inhibition or knockout of SlTDC up-regulated the expression of senescence genes and the accumulation of reactive oxygen species（ROS）in tomato leaves under dark treatment，which accelerated leaf senescence. Moreover，field application studies showed that exogenous MT could also significantly down-regulate the expression of senescence genes and accumulation of ROS in tomato senescent leaves（leaf age > 35 d）in solar greenhouse，and delay leaf senescence caused by increasing leaf age. In summary，MT can accelerate the removal of ROS by down-regulating the expression of senescence genes and up-regulating antioxidant capacity，and then delay the senescence of dark or leaf-age-dependent tomato leaves.

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• Effects of Water Deficiency on Sucrose and Starch Metabolism of Substrate Culture Tomato in Greenhouse
• CUI Yiqiong, LI Ju, LIU Xiaoqi, WANG Junwen, TANG Zhongqi, WU Yue, XIAO Xuemei, YU Jihua
• Acta Horticulturae Sinica. 2024, 51(11): 2607-2619. DOI:10.16420/j.issn.0513-353x.2023-0691
• Abstract ( 104 ) HTML ( 49 ) PDF (2201KB) ( 49 ) 　　　

• The purpose of this study was to explore the effects of sugar metabolism of tomato fruits under water deficiency cultivated in substrate. One of taste tomato cultivars‘181’and one of ordinary tomato cultivars‘Maofen 802’were selected as materials in this experiment. Four water treatment levels （full water supply，mild water deficit，moderate water deficit and severe water deficit）were set up to study the effects of water deficit on sugar components，enzyme activities and relative gene expression in tomato fruits related to sugar metabolism at green ripening stage，color turning stage and mature stage under substrate cultivation in solar greenhouse. The results showed that the response of sugar component and starch content to water deficit was different between the two cultivars. Moderate water deficit could increase the fructose and glucose contents of‘181’while decrease sucrose and starch content of‘181’at every stage. Severe water deficit could increase the fructose and glucose contents of‘Maofen 802’and the sucrose content decreased with the decrease of irrigation amount. The activities of sucrose synthetase （SS），sucrose phosphate synthetase（SPS），α-Amylase（α-AYM）and β-Amylase（β-AYM）in tomato ‘181’and‘Maofen 802’at maturity increased with the decrease of irrigation amount，and the activities were the highest under severe water deficit. Under severe water deficit，the relative expression levels of SS gene and SPS gene of the two tomato cultivars were up-regulated during color turning stage and mature stage. The α-AYM and β-AYM gene expression levels were up-regulated in green ripe stage under the water deficit. To sum up，moderate water deficit can promote the decomposition of sucrose and the production of fructose and glucose of substrate-grown tomatoes in greenhouse，ultimately improve the flavor quality of tomatoes.

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• Effects of Carbon Pool Strength on Plant Growth and Potassium Uptake of Tomato Intercropped with Potato-Onion
• LU Jianzeng, ZHOU Liyan, HUANG Xinyi, WU Fengzhi, GAO Danmei
• Acta Horticulturae Sinica. 2024, 51(11): 2620-2632. DOI:10.16420/j.issn.0513-353x.2023-0413
• Abstract ( 63 ) HTML ( 28 ) PDF (1477KB) ( 28 ) 　　　

• A pot experiment was conducted using tomato（Solanum lycopersicum L.）and potato-onion （Allium cepa L. var. aggregatum G. Don）in itercropping system to study the effects of shading（25%，50%）defoliation（25%，50%）and adjusting the size of planted tomato seedlings（tomato seedlings with two cotyledons or with two leaves planted with potato-onion）on carbon pool strength of tomato. Shading and defoliation treatments were found to decrease tomato growth while enhancing the growth of potato-onions. Interestingly，reducing the individual differences between tomato and potato-onion plants promoted the growth of both two plants. Reduction of tomato carbon pool strength reduced abundance of the arbuscular and hypha infection rate of tomato and potato-onion，but increased the abundance of vesicular. The potassium concentration in leaves and roots of potato-onion and the potassium concentration in leaves tomato were decreased，but increasing in roots of tomato instead after defoliation and adjusting the size of plant seedlings. Moreover，the rising concentration of potassium in leaves and roots of the tomato and potato-onion were respectively observed in shading 50% and 25% treatment. Shading and transplanting smaller tomato seedlings did not affect the available potassium content in the soil for potato-onions. Conversely，defoliation and transplanting smaller tomato seedlings reduced the available potassium in the soil for tomato，and weakened the tomato carbon pool strength can lead to a decrease in soluble sugar content in both plants. Overall，the reduction of carbon pool strength in tomato decreased to promoting effects of potato-onion on tomato plant growth，and reduced the role of arbuscular mycorrhizal fungi in the intercropping benifits between potato-onion and tomato system.

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• Effect of Exogenous Melatonin on the Cold Tolerance of Cucumber in Solar-Greenhouse
• FENG Yiqing, QIU Shengnan, WU Yue, XIE Yang, ZHANG Xiaowei, BI Huangai, AI Xizhen
• Acta Horticulturae Sinica. 2024, 51(11): 2633-2644. DOI:10.16420/j.issn.0513-353x.2023-0772
• Abstract ( 178 ) HTML ( 58 ) PDF (3111KB) ( 58 ) 　　　

• To explore the regulation mechanism of exogenous melatonin（MT）on the cold tolerance of cucumber plants，‘Jingyou 35’cucumber plants were used as materials，75 μmol · L^-1 MT was sprayed on the foliage to study its effects of exogenous MT on the photosynthesis，reactive oxygen species（ROS）accumulation，antioxidant enzyme activities of cucumber in winter solar greenhouse. The results showed that the photosynthetic rate（P_n），stomatal conductance（G_s），transpiration rate（T_r），maximum photochemical efficiency（F_v/F_m）and actual photochemical efficiency（Φ_PSII）decreased，while the intercellular CO₂ concentration（C_i）increased gradually，with the temperature decrease. Low temperature led to an increase in the accumulation of MDA，hydrogen peroxide（H₂O₂）and superoxide anion（$\mathrm{O}_{2}^{\bar{·}}$），as well as the electrolyte leakage rate（EL）. The activities of superoxide dismutase（SOD），peroxidase（POD），ascorbate peroxidase（APX）and glutathione reductase（GR）increased in the early days of low temperature stress，but subsequently decreased. Compared with the control，the MT treatment displayed a markedly increase in P_n，G_s，T_r，F_v/F_m and Φ_PSII，as well as the activity of Ribulose-1,5-diphosphate carboxylase（RuBPCase）and Rubisco activase（RCA）and their relative mRNA expressions，whereas an obviously decrease in C_i，after cold snap. The MT treated plants showed significantly lower MDA，H₂O₂ and $\mathrm{O}_{2}^{\bar{·}}$ accumulations and EL，while markedly higher activities of SOD，POD，APX and GR than those of the control. The yield of MT treatment increased by 16.3% compared with the control. These data suggest that exogenous MT can improve the cold tolerance of cucumber plants in solar-greenhouse by increasing the activities of Calvin cycle and photosystem，and enhancing the ROS scavenging activity during low temperature stress.

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• Analysis and Model Prediction of Factors Affecting the Binding Force of Fruit Stalks of Wolfberry
• CHEN Yun, LIU Quancheng, JIANG Xinna, WEI Yuqing, WANG Fan, YAN Lei, ZHAO Jian, CAO Xingda, XING Hong
• Acta Horticulturae Sinica. 2024, 51(11): 2645-2656. DOI:10.16420/j.issn.0513-353x.2024-0466
• Abstract ( 140 ) HTML ( 32 ) PDF (3724KB) ( 32 ) 　　　

• To analyse the intrinsic connection and influence law between the stalk binding force of wolfberry and its related physical property parameters，to discover the important fruit parameters，and to establish a prediction model of stalk binding force，with a view to providing a basis for improving the efficiency and accuracy of mechanical picking of wolfberry. Taking the ripening fruit of‘Ningqi 1’and ‘Ningqi 7’，the main cultivars of wolfberry in Qinghai Province，as the research object，the RGB colour model components of wolfberry fruits with different maturity were obtained by image processing methods，and different cultivars，maturity were analysed，temperature，humidity and the position of the fruit on the branch on the impact of the stalk binding force，as well as the correlation between the stalk parameters，fruit parameters and the stalk binding force，to construct a prediction model of the stalk binding force. The results showed that the maturity could be distinguished by the RGB colour model，but the overlapping part of the stalk binding force of different maturity levels was large，which could not be achieved for precise picking. The results of two-way ANOVA showed that both cultivar and maturity had a significant effect on the binding force；stalk parameters，fruit parameters and fruit hardness were significantly correlated with the stalk binding force；orthogonal tests showed that the position of the fruit on the branch，temperature and humidity at the time of picking did not have a significant effect on the binding force. The parameters of partial least squares regression（PLSR），random forest（RF）and back-propagation neural network（BPNN）modelling methods were optimised to establish a prediction model for fruit stalk binding，in which the BPNN showed excellent prediction performance（R_p² = 0.888，RMSEP = 0.440，RPD = 2.756），which was able to achieve effective prediction of fruit stalk binding.

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• Screening Research and Comprehensive Evaluation of Rooting Agents for Chrysanthemum Cuttings
• WU Yajie, JIAO Yu, WANG Hailong, CHEN Zhixing, PU Hao, ZHU Zihan, ZOU Qian, TANG Shukun, CAO Yanru
• Acta Horticulturae Sinica. 2024, 51(11): 2657-2667. DOI:10.16420/j.issn.0513-353x.2023-0674
• Abstract ( 195 ) HTML ( 151 ) PDF (2070KB) ( 151 ) 　　　

• In order to screen out the rooting agent that has a good effect on the rooting of chrysanthemum cuttings under the condition of barren red soil，the red soil was used as the substrate，and different rooting agents were used to treat the chrysanthemum cuttings，and the phenotypic indexes such as rooting rate，rooting time，root length，root number，root dry weight，and root thickness were determined. The effect of rooting agent was evaluated by principal component analysis. In order to explore the mechanism of growth-promoting seedlings of chrysanthemum cuttings treated with rooting agent，nutrients，hormone content and enzyme activity were determined，and the main physiological indexes affecting the rooting of chrysanthemum cuttings were clarified by extreme analysis. Principal component analysis（PCA） converted 7 individual indexes of rooting phenotype into 2 independent composite indexes，with a cumulative contribution rate of 89.69%. According to the comprehensive score of rooting of chrysanthemum cuttings，Nashi 778 has the highest score. Compared with the control，the rooting time was advanced by 2 days，the rooting rate increased by 34.44% on the 15th day，the number of roots at the 30th day increased by 97.80%，the root dry weight increased by 54.97%，and the root thickness increased by 24.24%. The second score of Double Gil GGR-6 was 78.64% higher than that of the control in root length. Among the physiological indexes of cuttings，the IAA range was the largest，which was the key factor affecting the rooting of chrysanthemum cuttings. Soluble protein content is the most important nutrient affecting the rooting of chrysanthemum cuttings. In conclusion，Nashi 778 inducer and Double Gil GGR-6 had good root-promoting effects，and could be used as excellent rooting agents for promoting chrysanthemum cuttings.

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Plant Protection

• Influences of Interactions Between Erwinia amylovora and Valsa pyri on Growth and Pathogenicity
• CHEN Chunqiao, SUN Liying, SHENG Qiang, HAN Jian, FU Benzhong, LUO Ming
• Acta Horticulturae Sinica. 2024, 51(11): 2668-2684. DOI:10.16420/j.issn.0513-353x.2024-0134
• Abstract ( 94 ) HTML ( 17 ) PDF (2718KB) ( 17 ) 　　　

• Fire blight and pear Valsa canker，two prominent diseases，currently inflict substantial damage on the production of Korla fragrant pear（Pyrus sinkiangensis）. Their often co-occurrence in the field，exacerbating the severity of the diseases and complicating control efforts. In order to clarify the interaction between the fire blight pathogen bacterium（Erwinia amylovora，E.a）and the pear Valsa canker pathogen fungus（Valsa pyri，V.p），and to explore the complex infection mechanisms of these pathogens，the present study was conducted to investigate the effects of pathogen interactions on the growth and pathogenicity of E.a and V.p by using E.a strain E.a001 and V.p strain V.pKRL fermentation filtrates co-culture. The results showed that co-culture of E.a001 with V.pKRL fermentation filtrates significantly enhanced the growth rate of E.a001，with a higher viable cell count compared to the control，and a 2.2-fold increase in biofilm formation compared to the control. Co-culture of V.pKRL with E.a001 frmentation filtrates resulted in a 1.46-fold increase in V.pKRL mycelial biomass，and a 14.9% increase in conidial germination rate compared to the control. Additionally，both co-culture of E.a001 with V.pKRL and V.pKRL with E.a001 fermentation filtrates reduced the pH of the culture medium，whereas co-culture of E.a001 with the reference strains of Alternaria alternata，and V.pKRL with Pseudomonas syringae and Dyckeya fangzhongda sp. nov did not exhibit growth promotion or pH reduction characteristics. It was found that co-culture of E.a001 + V.pKRL fermentation filtrate increased the extracellular polysaccharide and pear fire blight toxin production of E.a001. The relative expression of HrpA，hrpB，hrpD，hrpJ，HrpW，hrpY and hrcJ in the hrp gene cluster was up-regulated by 1.53 to 2.27-fold，with the greatest up-regulation of the hrpY gene. Similarly，E.a001 fermentation filtrate increased the synthesis of V.pKRL phlorizin degradation toxins，and the relative expressions of cell wall degradation-related enzyme genes，PG，β-Gal，PME and α-Af were up-regulated by 1.64 to 1.91-fold，with the largest up-regulation of the PG gene. Pathogenicity assessments on Korla fragrant pear ranches，leaves，and fruits revealed that sequential composite inoculation of E.a001 and V.pKRL at the same site induces the most potent pathogenicity，marked by rapid symptom development，lesion expansion，and increased V.p spore production compared to single or sequential inoculations at different sites. These findings underscore mutual promotion between E.a and V.p，enhancing toxin production，up-regulating pathogenic gene expression，and reinforcing pathogenicity，thereby indicating a specific cooperative interactions relationship between the two pathogens.

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• An Investigation on Occurrence and Distribution Patterns of Five Common Citrus Diseases in Yunnan
• NIE Ruihan, SUN Manli, FENG Di, SONG Xietian, GAO Junyan, GUO Lina, DENG Xiuxin, CHAI Lijun, XIE Zongzhou, YE Junli
• Acta Horticulturae Sinica. 2024, 51(11): 2685-2700. DOI:10.16420/j.issn.0513-353x.2023-0766
• Abstract ( 226 ) HTML ( 149 ) PDF (3310KB) ( 149 ) 　　　

• To clarify the occurrence and distribution of citrus diseases caused by“Candidatus Liberibacter asiaticus”（CLas），citrus yellow vein clearing virus（CYVCV），citrus tatter leaf virus （CTLV），citrus exocortis viroid（CEVd）and citrus tristeza virus（CTV）in Yunnan Province. In this study，577 citrus leaf samples were collected from 38 counties of 14 major citrus producing states in Yunnan Province. The pathogens of the above five citrus diseases were detected by nested PCR and RT-PCR，phylogenetic tree was constructed by genetic evolution analysis. The analysis showed that the positive rates of CLas，CYVCV，CTLV，CEVd and CTV were 36.0%，33.6%，15.1%，13.0% and 82.0%，respectively. CLas and CTV occurred in all the detected cities. From the citrus species，sweet orange exhibited the highest detection rates of CYVCV，CLas and CTV，followed by mandarin and lemon. Notably，the detection rate of CTV in lemon（40.0%）was obviously lower than that in mandarin（87.4%）and sweet orange（92.2%）. While the detection rate of CTLV and CEVd in sweet orange was only 5.9% and 4.0%，respectively，and was lower than mandarin and lemon. Based on the correlation analysis，results revealed a negative correlation between CLas occurence and altitude. It was also found that the correlations of CYVCV and CTV，CTLV and CEVd occurs frequently，whereas the correlation of CLas and CEVd was rarely detected，suggesting correlations among citrus diseases. Through genetic evolution analysis，it was found that the introduction and internal spread of pathogens in Yunnan were both important ways for the spread of the pathogens.

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New Technology and New Method

• Establishment of RT-RPA-LFD Method for Rapid Detection of Telosma Mosaic Virus in Passiflora
• DING Huijiao, WANG Hao, BAO Fangwei, SUN Geng, PANG Jingjun, FAN Zaifeng, ZHAO Wenjun, ZHOU Tao
• Acta Horticulturae Sinica. 2024, 51(11): 2701-2709. DOI:10.16420/j.issn.0513-353x.2023-0701
• Abstract ( 76 ) HTML ( 17 ) PDF (2007KB) ( 17 ) 　　　

• Primers and probe were designed according to the coat protein（CP）gene of telosma mosaic virus（TeMV）on passion fruit，and recombinase polymerase amplification（RPA）was combined with lateral flow dipstick（LFD）to establish a method for rapid detection of TeMV. The reaction time，temperature，probe concentration and primers concentration of the method were optimized，and then the specificity and sensitivity of the metho also were examined. The experimental results show that the optimal reaction temperature was 37 ℃，optimal reaction time was 13 min，optimal probe concentration was 5 μmol · L^-1，and the optimal primers concentration was 10 μmol · L^-1. The method can specifically detect TeMV，and the minimum detection limit could reach to 5.125 × 10^-4 ng · μL^-1 for plasmids containing TeMV cp，which is ten thousand times more sensitive than ordinary PCR detection. This method has high sensitivity and specificity，which can be used to detect passion fruit samples in the field.

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• Construction of Virus-Mediated Genetic Transformation System of Camellia sinensis
• HU Jinyu, LIU Guizhi, CHEN Lan, HUANG Mengdi, SU Qin, TAN Yueping, LIU Shuoqian, TIAN Na
• Acta Horticulturae Sinica. 2024, 51(11): 2710-2724. DOI:10.16420/j.issn.0513-353x.2024-0075
• Abstract ( 147 ) HTML ( 60 ) PDF (2876KB) ( 60 ) 　　　

• In this study，Camellia sinensis phytoene desaturase gene（CsPDS）and tea caffeine synthase gene（TCS1）as indicator genes and Nicotiana benthamiana as a vector were employed to enrich tobacco rattle virus. The effects of the concentration of infiltration solution，incubation temperature，different vectors and incubation time on the enriched viruses were investigated，with N. benthamiana used as the vector to enrich the viruses. The effects of different inoculation methods and cultivars on the construction of a virus-induced gene silencing（VIGS）system were also investigated in tea plant. The results demonstrated that inoculation of tobacco with acetosyringone（AS）at a concentration of 200 μmol · L^-1 bacteriophage with an optical density（OD₆₀₀）of 1.0 was conducive to virus enrichment in tobacco when incubated at 23 ℃. The leaves of‘Shuchazao’were used to construct the VIGS system of tea plant by injection inoculation, and the system was successfully used to explore the possibility of foreign gene expression with GFP as the indicator gene.

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New Cultivars

• A New Early-Ripening Yellow Flesh Actinidia chinensis Cultivar‘Heijin’
• LIU Yanfei, HE Xin, HE Haohao, LIU Zhande
• Acta Horticulturae Sinica. 2024, 51(11): 2725-2726. DOI:10.16420/j.issn.0513-353x.2021-1233
• Abstract ( 110 ) HTML ( 41 ) PDF (1085KB) ( 41 ) 　　　

• ‘Heijin’is a new early-ripening Actinidia chinensis cultivar with yellow flesh，bred from the seedling selection of ‘Huayou’. The fruit is nearly ovoid in shape，with brown or slightly black skin，and the average weight of fruit is 104.83 g. The flesh color is golden yellow，the core color is yellow-white，and with tender，juicy taste and strongly aromatic. The content of soluble solids，total sugar，titratable acidity and vitamin C are 20.4%，13.1%，0.63% and 1 160 mg · kg^-1，respectively. The fruit is ripe in the middle of September in Guanzhong District of Shaanxi Province，with an average yield of 27 700 kg · hm^-2 in the full fruit stage.

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• A New Cultivar of Seabuckthorn‘Xuedihuang’
• ZHANG Haiwang, LIU Lina, WANG Hongjiang, ZHANG Dongwei, ZHANG Wenchen
• Acta Horticulturae Sinica. 2024, 51(11): 2727-2728. DOI:10.16420/j.issn.0513-353x.2021-1213
• Abstract ( 71 ) HTML ( 31 ) PDF (1187KB) ( 31 ) 　　　

• ‘Xuedihuang’seabuckthorn is an excellent cultivar bred for the offspring of the cross between Ulangemu（♀）and Aliei（♂）.The‘Xuedihuang’seabuckthorn is a small backbone tree with few thorns and strong resistance. The fruit is short and cylindrical，the color of the fruit is orange，and the fruit is bright. The horizontal diameter of the fruit is 0.80 cm，the vertical diameter of the fruit is 0.94 cm，the weight of one hundred fruit is 49.19 g，the highest yield of per plant for 5 years is 18.66 kg. The fruit is aromatic，sweet and sour，and partly bitter. It has drought，cold，barren and saline-alkali resistance. It does not fall through winter in Chaoyang area，Liaoning.

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• A Novel Cherry Tomato Cultivar‘Fenbao 2’
• HE Jie, DENG Junjun, GAO Min, ZHU Honghua, WANG Binglin, SUN Hongbo, YANG Yuan, YAN Han
• Acta Horticulturae Sinica. 2024, 51(11): 2729-2730. DOI:10.16420/j.issn.0513-353x.2023-0718
• Abstract ( 73 ) HTML ( 32 ) PDF (1256KB) ( 32 ) 　　　

• ‘Fenbao 2’is a novel F₁ hybrid cultivar of cherry tomato，resulting from the crossing between female parent pureline qx08-4-6 and male parent pureline xn15-1-5. This cultivar exhibits indeterminate growth habits，and vigorous vine plant. The oval-shaped fruits are deeply-pink colored，possess a sweet taste，and superior quality，and display a green shoulder during the immature period. On average，the fruits weigh 20 g and contain 9.8% soluble solids content，6% total sugar，57.93 mg · kg^-1 lycopene，and 100.4 mg · kg^-1 vitamin C. The yield is between 42 000-45 000 kg · hm^-2. The growth period is 124 days，medium or off-season maturity. Additionally，it is resistant to root knot nematodes and leaf mould disease. This cultivar is well-suitable for greenhouse cultivation in early spring，particularly，in regions with weather conditions akin to Shaanxi Province.

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• A New Clerodendrum japonicum Cultivar‘Zhuangyuanhong 1’
• WANG Yinghua, LI Xiaojun, CHEN Gang
• Acta Horticulturae Sinica. 2024, 51(11): 2731-2732. DOI:10.16420/j.issn.0513-353x.2021-1203
• Abstract ( 69 ) HTML ( 18 ) PDF (1754KB) ( 18 ) 　　　

• ‘Zhuangyuanhong 1’is a new cultivar systematically selected and bred from real seeds of（Clerodendrum japonicum）. The plants are perennial deciduous and evergreen shrubs. The plant architecture of this cultivar is dwarf and compact，with lush and regular branches and leaves. Inflorescence is compact and round，and calyx，corolla and pedicel are red. Flowering period from May to November. It has the characteristics of good adaptability and high ornamental value. It is suitable for cultivation in southern China，and can be cultivated in flower bed，flower border，forest edge，etc.，as well as be used for cluster planting in lawns and potting.

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• A New Bletilla striata Cultivar‘Zheji 1’
• XING Bingcong, CHEN Jialong, WANG Hong, JIANG Wu, SHANG Liangting, ZHU Jianjun
• Acta Horticulturae Sinica. 2024, 51(11): 2733-2734. DOI:10.16420/j.issn.0513-353x.2024-0257
• Abstract ( 63 ) HTML ( 29 ) PDF (2393KB) ( 29 ) 　　　

• ‘Zheji 1’is a new cultivar selected from wild Bletilla striata in Qingliangfeng Town，Linan City，Zhejiang Province. The plant of‘Zheji 1’showed vigorous growth，with large leaves and tubers. In the fourth year of planting，the field facility cultivation fresh weight 23 611 kg · hm^-2，39.38% higher than the control（Provenance of Taishun，Zhejiang）；the fresh weight of the forest container cultivation 11 022 kg · hm^-2，20.32% higher than the control（Provenance of Taishun，Zhejiang）. The content of militarine in‘Zheji 1’is 4.25%. The new cultivar is suitable for cultivation in most of the Zhejiang regions.

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