Genetic & Breeding·Germplasm Resources·Molecular Biology

• Cloning and Functional Analysis of the CDS and Promoter of Synthase Gene STS19 in Chinese Wild Grapevine
• LIU Hui, YIN Xiangjing, FANG Jinghao, GAO Min, LI Zhi, WANG Xiping
• Acta Horticulturae Sinica. 2023, 50(7): 1389-1401. DOI:10.16420/j.issn.0513-353x.2022-0478
• Abstract ( 470 ) HTML ( 402 ) PDF (3610KB) ( 402 ) 　　　

• VaSTS19 and VdSTS19 were cloned from Vitis amurensis Rupr.‘Tonghua 3’and V. davidii Foex.‘Tangwei’. Sequence analysis showed that the open reading frame of VaSTS19 and VdSTS19 were 1 179 bp，encoding 392 amino acid，and they were located on chromosome 16. The identity between VaSTS19 and VdSTS19 nucleotide and amino acid was 98.81% and 98.21%，respectively. Both VaSTS19 and VdSTS19 are located on the cytomembrane，cytoplasm and nucleus. The expression of STS19 gene and the synthesis and accumulation of resveratrol were significantly promoted when VaSTS19 and VdSTS19 were transferred into tomato by Agrobacterium-mediated method. The promoters of VaSTS19 and VdSTS19 were cloned from‘Tonghua 3’and‘Tangwei’，respectively. cis-Acting elements analysis showed that both promoters contained stress-related elements，hormone-related elements and light-related elements. A sequence alignment showed that the VaSTS19 promoter was demonstrated 60% homology with the VST2 promoter cloned from V. vinifera. The promoters of VaSTS19 and VdSTS19 and their fragments were significantly responsive to SA and MeJA induction in transgenic tobacco leaves. The results indicated that the expression pattern of STS19 and the production of resveratrol may be related to the regulation of the upstream region.

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• Identification of F₁ Hybrids and Analysis of Fruit Shape Difference Between Fingered Citron and Citron
• MEI Yulin, XU Jinjian, JIANG Mengyue, YU Junhai, ZONG Yu, CHEN Wenrong, LIAO Fanglei, GUO Weidong
• Acta Horticulturae Sinica. 2023, 50(7): 1402-1418. DOI:10.16420/j.issn.0513-353x.2022-0745
• Abstract ( 930 ) HTML ( 212 ) PDF (4228KB) ( 212 ) 　　　

• In this study，19 F₁ hybrids derived from the cross between Citrus medica L. and C. medica var. L. sarcodactylis Swingle were cultured as materials. SSR loci were selected from the transcriptome data of fingered citron and citron. Based on this，TP-M13-SSR primers were designed and then 19 F₁ hybrids were genotyped. A total of 17 to 32 alleles were obtained from 16 SSR primers，and the average number of alleles was 24.188. The heterozygosity was ranged from 0.188 to 1.000，and the polymorphism index was about 0.944. The results showed that 17 out of 19 F₁ lines were true hybrids，and the hybridization rate was 89.47%. Those materials were phenotyped by morphological photography analysis and the ratio of finger fruit to hesperidium is 2︰3. Paraffin section analysis of early flower buds of fingered citron and citron found the difference between their fruit shape initiating from the carpel bulges since the visible bud stage to the petals emerging stage. From the visible bud stage to 3 d after anthesis of fingered citron and citron，the correlation analysis between the transcriptome data and carpel feature was done，and a number of genes associated with gynoecium formation were identified. These genes were validated in the pistils of citron，fingered citron，and hybrid F₁ lines during the pre-anthesis stage. The results showed that the expression of WOX1 was related to the character of finger fruit from the visible bud stage to the petals emerging stage. The YABBY family coordinated with the classes C，E genes of the ABC model of flower development and WOX family to regulate the fruit shaping in fingered citron.

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• The Creation and Study on Characteristics of New Material of Autotetraploid Purple Tsai-tai
• ZHANG Chen, LI Mengjie, YANG Xiaoxue, WANG Meiyun, XIAO Dong, WANG Jianjun, HOU Xilin, HU Jun, LIU Tongkun
• Acta Horticulturae Sinica. 2023, 50(7): 1419-1428. DOI:10.16420/j.issn.0513-353x.2022-0686
• Abstract ( 281 ) HTML ( 124 ) PDF (2652KB) ( 124 ) 　　　

• In order to create new germplasm resource of tetraploid purple tsai-tai（Brassica campestris var. purpurea Bailey），0.2 g · L^-1 colchicine solution was used to drip the apical shoot of diploid. Then，autotetraploid plants were identified by morphology，anatomy and cytology methods. Through the analysis of agronomic characters，the plant height，spreading degree，leaf width and leaf stalk length of tetraploid plants increased significantly. However，the number of leaves of tetraploid significantly reduced. In nutritional quality，the content of soluble protein and anthocyanin in tetraploid plants increased significantly，while the content of soluble sugar，fibrin and nitric nitrogen in tetraploid plants significantly reduced compared with diploid. The analysis of photosynthetic characteristics showed that the net photosynthetic rate，interintracellular CO₂ concentration，stomatal conductance and transpiration rate of tetraploid plant were higher than that ofdiploid，indicating that tetraploid plants were more adaptable to strong light. The analysis of disease resistance showed that the tetraploid plants had stronger disease resistance.

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• Drought Tolerance Improvement of Processing Tomato by Molecular Marker Assisted Selection
• SHEN Xinyan, HOU Xiaolei, SUN Peinan, LIU Minmin, TANG Yaping, LI Ning, LU Yong’en, YE Zhibiao, OUYANG Bo
• Acta Horticulturae Sinica. 2023, 50(7): 1429-1443. DOI:10.16420/j.issn.0513-353x.2022-0695
• Abstract ( 290 ) HTML ( 245 ) PDF (3001KB) ( 245 ) 　　　

• Molecular marker-assisted selection was used to improve the drought tolerance of two processing tomato lines（Rigel 87-5 and M3）. In this breeding process，a drought-tolerant tomato line（M1040）was used as the donor，while Rigel 87-5 and M3 were used as the recurrent parents. The drought-tolerant molecular marker ID68 was used to select the backcrossing materials for four backcross generations. The drought tolerance of the improved lines（Rigel 87-5D and M3D）at seedling stage was evaluated in detail. The results showed that the survival rate of 87-5D and M3D was significantly higher than that of the recurrent parent after severe drought and rehydration，which can also be reflected by the curve of injury index. The growth，physiological and biochemical indicators under moderate drought stress showed that the improved lines were clearly better than the recurrent parents. Comparison of agronomic traits suggested that the genetic background of the improved lines was restored.

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• Karyotype and Fertility Analysis of Allotetraploids in Tree Peony（Paeonia section Moutan）
• ZHONG Yuan, DU Mingjie, CHENG Fangyun, LI Kunyan, JI Runze, CUI Jun
• Acta Horticulturae Sinica. 2023, 50(7): 1444-1454. DOI:10.16420/j.issn.0513-353x.2022-0413
• Abstract ( 330 ) HTML ( 114 ) PDF (2562KB) ( 114 ) 　　　

• Three allotetraploid tree peony materials were first found by karyotype analysis，and their fertility characteristics and breeding potentiality were analyzed based on hybridization test. The results showed that each of the three materials had 20 chromosomes，and the karyotype formulas were as follows：07-LB-30：2n = 4x = 20 = 16m（1SAT）+ 4st（1SAT），07-LB-22：2n = 4x = 20 = 15m（1SAT）+ 1sm （1SAT）+ 4st（3SAT），07-LB-56：2n = 4x = 20 = 16m（3SAT）+ 4st. The hybridization test showed that 07-LB-30 was a superior parent material with good fertility either as male or female parent. 07-LB-22 was an excellent male sterile female parent and of great value in breeding. 07-LB-56 was sterile as the female parent，but showed some fertility as male parent in hybridization，which leads it to an important material for breeding polyploid tree peony with double flower type.

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• Creation of Triploid Germplasm in Paeonia ostii‘Fengdan’Through 2n Female Gametes Inducing with High Temperature Treatment
• LIU Chunyang, PENG Chaofeng, CHENG Shiping, YAO Pengqiang, GENG Xining, XIE Lihua
• Acta Horticulturae Sinica. 2023, 50(7): 1455-1466. DOI:10.16420/j.issn.0513-353x.2022-0699
• Abstract ( 275 ) HTML ( 103 ) PDF (2886KB) ( 103 ) 　　　

• High temperature treatment with“a non-in-vitro branch bud heat treatment device of trees”（ZL200610113448.X）was used to induce 2n female gametes of five-year-old Paeonia ostia‘Fengdan’in order to obtain polyploid germplasm. The results showed that the meiosis process of megaspore mother cell was time series correlated to the outward morphology of flower bud and microspore development state. Triploid plants with the highest ratio（2.45%）could be obtained in the natural pollinated progeny population，when the flower buds were treated at 40 ℃ for four hours in the“big wind-bell”stage and three to four days after the mononuclear pollen stage of the microspores.

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• Effects of Shading on the Variation of Sepal Color and Pigment Composition in Hydrangea macrophylla‘Hanatemari’
• YANG Jun, KONG Yu, LIU Qunlu, YE Kang, QIN Jun
• Acta Horticulturae Sinica. 2023, 50(7): 1467-1481. DOI:10.16420/j.issn.0513-353x.2022-0528
• Abstract ( 229 ) HTML ( 144 ) PDF (2561KB) ( 144 ) 　　　

• The effects of full light and 50% shading on sepal color and pigment composition in different blooming periods of Hydrangea macrophylla‘Hanatemari’were studied. The color phenotype was determined by the Royal Horticultural Society colorimetric card and colorimeter. Anthocyanin composition was qualitatively and quantitatively analyzed by high-performance liquid chromatography and mass spectrometry（LC-MS）. Physiological indexes，such as the biosynthetic enzyme activities and metal ion contents，were determined. The correlation between sepal color and physiological indexes was analyzed through multiple linear regression analysis. Results showed that shading considerably affected the sepal color of H. macrophylla. The sepal color under 50% shading had lower redness value（a^*），higher yellowness value（b^*），and presented to be more pinkish（greyed-purple group）than that under full light. Fading speed of sepal color was retarded under 50% shading. From the full blooming to the withering period of flowers，the redness value a^* under full light decreased by 88.90%，whereas it only decreased by 65.67% under 50% shading. Five anthocyanidins（cyanidin，pelargonidin，delphinidin，malvidin，and petunidin）were detected in the sepal，and 11 anthocyanins were formed through glycosylation modification. Delphinium-3-O-glucoside，accounting for 92.12% of anthocyanin components，was the main reason for the coloration of hydrangea sepal. Later，50% shading was beneficial for anthocyanin accumulation，and the total anthocyanin content（1 286.96 µg · g^-1FW）was significantly increased by 36.32% compared with full light（944.10 µg · g^-1FW）. The activities of phenylalanine ammonia-lyase （PAL）and chalcone isomerase（CHI）were higher at the initiation stage，and the PAL activity was significantly higher under 50% shading at the budding stage than under full light. However，shading did not cause considerable changes in Al，Fe，Ca，and Mg contents. Multiple regression analysis showed that delphinidin，malvidin，and petunidin accumulations were beneficial to the redness of sepal color. Total anthocyanins played a dominant role in the coloration of H. macrophylla sepal under different treatments，and through synergistic effects of flavonoids，total phenols，PAL，and CHI enzyme activities，jointly affected the sepal color presentation.

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• Genome-wide Identification of GASA Family and Preliminary Exploration of Leaf Variegation Formation in Begonia masoniana
• XUE Zhenzhen, GUAN Hongfa, LI Na, LI Lingfei, ZHONG Chunmei
• Acta Horticulturae Sinica. 2023, 50(7): 1482-1494. DOI:10.16420/j.issn.0513-353x.2022-0472
• Abstract ( 238 ) HTML ( 106 ) PDF (1660KB) ( 106 ) 　　　

• In order to understand the potential functions of Gibberellic Acid-stimulated Arabidopsis （GASA）in Begonia masoniana（BmaGASAs），the bioinformatics analysis was carried out to identify the members of BmaGASA gene family，and then their expression patterns were analyzed. The results showed that ten members of the GASA family were distributed in four subgroups. The structural characteristics of BmaGASAs include 2-3 motifs，one GASA conserved domain，0-10 introns that varies among different members. The cis-acting elements distribution analysis showed that the BmaGASAs promoters contained abundant light and hormone response elements. BmaGASAs were widely expressed in various tissues and organs. In addition，BmaGASAs had significant differences in response to GA，ABA，SA，MeJA and auxin. This study indicates that members of the BmaGASA gene family are highly conserved and have diverse expression patterns. They may be involved in the growth and development of various tissues and organs，as well as the response processes of various biological or abiotic stress. Among them，BmaGASA7 may play an important role in leaf variegation formation.

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• Analysis of Flora Volatiles of the Hybrids and Their Parents in Daylily （Hemerocallis）
• JIAO Fang, SUN Guofeng, LI Lifang, ZHANG Jinzheng
• Acta Horticulturae Sinica. 2023, 50(7): 1495-1504. DOI:10.16420/j.issn.0513-353x.2022-0385
• Abstract ( 573 ) HTML ( 128 ) PDF (1058KB) ( 128 ) 　　　

• Eighteen F₁ hybrids from three cross combinations of Hemerocallis and their parents were used as materials，and the floral volatiles were qualitatively and quantitatively determined by headspace solid-phase extraction combined with gas chromatography-mass spectrometry（HS-SPME-GC-MS）. Relative release rate of the two main flora volatiles which decide the fragrance and the total floral volatiles of the tested materials were analyzed. One-way SIMPER analysis was performed to figure out the percentage of similarity with parents. Result showed that：（1）The composition and content of the floral volatiles of the F₁hybrids of the three hybrid combinations were similar to their parents，when the female parent is the same，the higher the relative release rate of the floral volatiles of the male parent，the higher the relative release rate of the floral volatiles of its F₁ hybrids；（2）If the main floral volatile of the hybrid parents were (E)-β-ocimene，the F₁ hybrids also contained higher amount of (E)-β-ocimene and the content of which was between the two parents，and the total amount of flora volatiles was also between the two parents；if the main flora volatiles of the parents contained both (E)-β-ocimene and linalool，the content of (E)-β-ocimene in some of the F₁ hybrids were higher than or similar to that of the parents，while the content of linalool was between the two parents，the total amount of floral volatiles was basically higher than that of the two parents；（3）Wild species with intense fragrance crossed with cultivars with no significant fragrance could breed fragrant F₁ hybrids，so they are good germplasm resources to breed fragrant daylilies.

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• Studies on Genetic Variation of‘Tieguanyin’Tea Trees Asexual Reproduction Based on High-depth Genome Resequencing
• HOU Binghao, GAO Ting, WEI Yuede, GAO Shuilian, CAI Yinbi, CHEN Zhiming, JIN Shan, ZHANG Xingtan, WANG Pengjie, YE Naixing
• Acta Horticulturae Sinica. 2023, 50(7): 1505-1517. DOI:10.16420/j.issn.0513-353x.2022-0521
• Abstract ( 241 ) HTML ( 58 ) PDF (2702KB) ( 58 ) 　　　

• The genome of Camellia sinensis（L.）O. Kuntze‘Tieguanyin’mother tree and its three consecutive asexual reproductions and three‘Tieguanyin’trees from multi-generation that used for actual production were resequenced with over 50× in this study. Through SNP and InDel detection and annotation，it was found that most of the variants were located in intergenic regions，only 1.09%-1.13% of SNPs and 0.51%-0.61% of InDels were located in gene coding regions. In the whole genome and coding regions，the total number of mutation sites of the three consecutive asexual reproductions had little differences，and the number of genes involved in the mutation was basically the same in each sample. It was speculated that the varietal characteristics of‘Tieguanyin’had been generally stable during asexual reproduction. The KEGG（Kyoto Encyclopedia of Genes and Genomes）enrichment analysis showed that purine and carbohydrate metabolic pathways were significantly enriched in three ‘Tieguanyin’trees used for actual production，and the caffeine metabolic pathway was extremely significant enriched. It was speculated that some of the quality and flavor-related metabolic pathway genes were varied during the long-term asexual reproduction process in‘Tieguanyin’. Compared with the three consecutive asexual reproductions，the sequence of three genes such as FAR1，WAT1，and MYB that related to growth and development and five genes such as PP2A，BTB/POZ，BAT2，RPP13，and Lr10 that related to stress response had been mutated in three‘Tieguanyin’trees used for actual production.

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Cultivation Physiology & Biochemistry

• Inhibition of Tagetes erecta Straw Powder on the Main Pathogens of Apple Continuous Cropping Obstacle and Its Field Application Effect
• WANG Xiaofang, XIA Qun, LUAN Risheng, XU Li, YIN Chengmiao, WANG Yanfang, CHEN Xuesen, MAO Zhiquan, XIANG Kun
• Acta Horticulturae Sinica. 2023, 50(7): 1518-1534. DOI:10.16420/j.issn.0513-353x.2022-0564
• Abstract ( 209 ) HTML ( 109 ) PDF (4140KB) ( 109 ) 　　　

• In order to explore the inhibitory effect and field control effect of Tagetes erecta straw powder on the pathogenic fungi related to apple replant disease（ARD），and the inhibitory effect of T. erecta on four Fusarium fungi（F. oxysporum，F. solani，F. proliferatum and F. verticillioides）was studied under indoor conditions. Under field conditions，two-year-old apple saplings（‘Yanfu 3’/M9T337）were used as test materials，and the effects of T. erecta straw powder on the growth of apple saplings and soil micro-ecological environment were studied. Seven treatments were designed as follows：replanted soil（control），methyl bromide fumigation，T. erecta mixed planting，0.5% and 1% T. erecta straw powder，0.5% and 1% corncob powder. The results showed that the volatile components of T. erecta had a strong inhibitory effect on the mycelial growth of the four Fusarium species. The inhibition rate of mycelial growth was 20%-100% at the concentration of 1.67-33.30 g · L^-1，and the inhibition rate increased with the increase of T. erecta dosage. The hyphae of F. solani treated with T. erecta was inhibited，the growth was messy，thin，the branches increased，short and thin，the hyphae gradually shrunken and collapsed，withered，and the surface was damaged. Under field conditions，the effect of 0.5% T. erecta straw powder treatment was the best in the Fengmaozhai test site，and the effect of 1% T. erecta straw powder treatment in the Wantoucun test site was the best. The plant height，ground diameter，and annual growth of branches of apple saplings were significantly higher than those of the control. The activities of soil enzymes treated with T. erecta were significantly increased；the number of culturable bacteria in the soil increased；the number of fungi decreased；the ratio of bacteria/fungus increased. In the Fengmaozhai test site，the relative abundance of Penicillium of 0.5% T. erecta powder treatment increased the most，which was 59 times that of the control. In Wantoucun test site，the relative abundances of Mortierella，Chaetomium，and Penicillium all increased after treatment，among which Penicillium increased the most，and the relative abundances of Penicillium with 1% T. erecta powder treatment was 125 times that of the control. Principal coordinate analysis（PCoA）showed that there were significant differences in soil fungal community structure of different treatments in Fengmaozhai and Wantoucun test sites. In conclusion，T. erecta straw crushed material can significantly improve soil microbial community structure and replanted soil environment，reduce the harm caused by ARD to apple saplings and promote the growth of apple saplings.

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• Study on the Standard of Nutrient Elements Contents in Eureka Lemon Leaves
• WANG Hongxiu, ZHOU Shangling, HE Shaoguo, TIAN Zaize, MA Jinghua, PENG Liangzhi, CHUN Changpin
• Acta Horticulturae Sinica. 2023, 50(7): 1535-1546. DOI:10.16420/j.issn.0513-353x.2022-0431
• Abstract ( 220 ) HTML ( 92 ) PDF (1079KB) ( 92 ) 　　　

• In the present study，the fruits and leaves from 70 different Eureka lemon orchards in Anyue County of Sichuan Province and Tongliang District of Chongqing were used as experimental materials to determine their main fruit quality parameters and the contents of leaf nutrient elements. The lemon orchards were divided into superior quality and normal orchards based on a established comprehensive evaluation model for lemon fruit quality. The criteria of nutrition diagnosis for Eureka lemon leaves was formulated according to the different grades of orchards. The results showed that four principal components were extracted from the fruit quality principal component analysis with a cumulative contribution of 80.54%. The results of the principal component analysis were used to calculate and rank the overall score of each orchard，which was used as an indicator to classify the orchards. The study of nutrient elements in lemon leaves of different orchards showed that N，K，Zn and B had a normal distribution，while P，Ca，Mg，S，Fe，Mn，and Cu were approximately χ² distributed. The standardized probability grading method was used to divide normally distributed elements into five levels：eficiency，lower，normal，higher，and excess. For elements that did not conform to the normal distribution，the probability classification method was corrected by referring to the nutrient elements in the leaves of superior quality orchards and the existing standard. In conclusion，preliminary standard for the nutrient elements of Eureka lemon leaves was developed.

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• Analysis on Growth，Physiology and Fruit Quality of‘Hongjiang’Orange Grafted with Different Rootstocks Under Container Culture
• CHEN Min, WU Tianli, Lü Yuanda, JIANG Bo, YAN Huaxue, LI Juan, ZHONG Yun
• Acta Horticulturae Sinica. 2023, 50(7): 1547-1562. DOI:10.16420/j.issn.0513-353x.2022-0256
• Abstract ( 537 ) HTML ( 186 ) PDF (2500KB) ( 186 ) 　　　

• This study evaluated the effects of four rootstocks，Ziyang Xiangcheng（Citrus junons Sieb. ex. Tanaka），Carrizo citrange（C. sinensis × Poncirus trifoliata），Trifoliate orange[P. trifoliata（L.）Raf.] and Flying Dragon（P. trifoliata var. monstrosa）on growth performance，physiology and fruit quality characteristics of‘Hongjiang’orange[C. sinensis (L.) Osbeck] scion cultivar. Their correlation and difference were analyzed to provide a reference for screening excellent rootstock of citrus cultivated in the insect-proof net and container. The experimental results showed that the grafting survival rate，root development，single-leaf weight and single fruit weight of Ziyang Xiangcheng rootstock were significantly higher than other rootstocks. The grafting interface healed completely in Ziyang Xiangcheng rootstock；however，the fruit quality was inferior compared with other rootstocks.‘Hongjiang’orange plants grafted with Carrizo citrange rootstock had the strongest growth vigor，with extremely low bark（phloem）in the stem. Moreover，the fruit quality of Carrizo citrange rootstock was also excellent，with a smooth peel and fewer grooves. It has significantly more soluble solids and total sugars in the flesh than other rootstocks；in contrast，soluble solids/acidity ratio，total flavonoids and amino acid content were substantially higher than Ziyang Xiangcheng rootstock. Flying Dragon and Trifoliate orange rootstocks had lower graft survival rates，incomplete graft healing，slow root development，and weak growth vigour than more vigorous rootstocks. Therefore，the combination of‘Hongjiang’orange grafted on Carrizo citrange rootstock performed good horticultural performance under container culture. Pearson correlation analysis showed that graft survival and tree vigour were positively correlated with IAA/ABA，GA₃/ABA and IAA/ZR at the grafting union；scion to stock trunk diameter ratio was negatively correlated with ZR，ABA and ZR/ABA in grafting union. Tree vigour was significantly negatively correlated with proportions of scion bark，leaf ABA level，IAA/GA₃，and significantly negatively correlated with leaf water content，N，K and Zn，but significantly positively correlated with leaf ZR/ABA. Root growth was negatively correlated with ZR，BR and ABA，and positively correlated with IAA/ZR and IAA/GA₃. The above indicates that hormonal interactions play an important role in grafting compatibility，vigour potential and root development of different rootstock combinations.

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• Analysis of Freezing Tolerances and Physiological Differences of Three Pomegranate Cultivars During the Overwintering
• TANG Haixia, YANG Xuemei, FENG Lijuan, ZHU Feng, ZHOU Jilei, YIN Yanlei
• Acta Horticulturae Sinica. 2023, 50(7): 1563-1573. DOI:10.16420/j.issn.0513-353x.2022-0551
• Abstract ( 1134 ) HTML ( 162 ) PDF (1394KB) ( 162 ) 　　　

• To study the change of freezing tolerance and its physiological basis of annual shoots of ‘Taishanhong’‘Luqing 1’and‘Tunisian Soft Seed’pomegranates during overwintering，the cold hardiness was estimated by the semi-lethal temperature（LT₅₀），which was assessed by electrolyte leakage rate with Logistic quation，the content of relative water，soluble protein，soluble sugar，malondialdehyde（MDA），activities of peroxidase（POD）and superoxidase（SOD），field overwintering rate，botanical characteristics of shoots，and the recovery ability of branches after freezing stress were measured. The results showed that the significant differences in cold resistance among three pomegranate cultivars. The overwintering rate of‘Luqing 1’was much higher than those of‘Taishanhong’and‘Tunisian Soft Seed’，and‘Tunisian Soft Seed’was the worst. Compared with‘Tunisia Soft Seed’，the shoots of‘Luqing 1’ were thick，hard，with short internodes，the spiness were also strong and hard. Sealing layers of lenticle were rich and tight. The changes of physiological indexes of‘Luqing 1’were relatively small after low temperature treatment. MDA content was low，soluble proteins content and POD activity were high. The osmotic pressure and redox balance of‘Luqing 1’could be maintained well，so its cold resistance much better than that of‘Tunisan Soft Seed’.

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Plant Protection

• Control Effect of Lysobacter enzymogenes LE16 on Rot Disease in Post-harvest Citrus Fruit Caused by Penicillium digitatum and P. italicum
• DENG Chengfeng, LI Suping, ZHANG Ruixuan, HAN Leng, LI Yong
• Acta Horticulturae Sinica. 2023, 50(7): 1574-1586. DOI:10.16420/j.issn.0513-353x.2022-0414
• Abstract ( 199 ) HTML ( 66 ) PDF (2326KB) ( 66 ) 　　　

• In order to prevent citrus fruit decay caused by Penicillium italicum and P. digitatum in postharvest，a self-screened strain of Lysobacter enzymogenes LE16 applied to test，and the inhibitory effects of self-digestive fermentation liquid and volatile organic compounds（VOCs）of LE16 on the mycelium growth and spore germination of P. italicum and P. digitatum were studied. In addition，the antibacterial components of self-digestive fermentation liquid were analyzed by liquid chromatography-mass spectrometry（LC-MS）. Furthermore，the control effect of strain LE16 on P. italicum and P. digitatum was determined by the fruit trauma inoculation and commercial simulation storage. Results from the pure culture experiment showed that both self-digestive fermentation liquid and volatile organic compounds significantly inhibited the mycelium growth of P. digitatum and P. italicum by 100% and 77.52%-91.11%，respectively. The self-digestive fermentation liquid also reduced the spore germination rate by > 96%，and resulted in the mycelial vacuolation and distortion. No significantly differences on the mycelium growth of P. digitatum and P. italicum were observed for the inhibition effect of self-digestive fermentation liquid that was treated under 80，90 and 100 ℃ for 30 minutes. The result of self-digestive fermentation liquid through LC-MS analysis showed that LE16 produced a number of secondary metabolites including cinnamaldehyde，cinnamic acid，dodecanoic acid and γ-butyrolactone and other antibacterial chemicals. In the fruit trauma inoculation test with P. italicum，the activities of superoxide dismutase and catalase in citrus peel were increased，but the content of malondialdehyde and cell membrane permeability was decreased. Significant decreases in the disease incidence and disease index of citrus fruit were ranked as the control > LE16 > prochloraz > 50% LE16 + 50% prochloraz，while the control efficacy showed an opposite trend. There were no significant changes in the quality of citrus fruits under the self-digestive fermentation liquid treatment during the commercial simulation storage. The control effects were 50.00% under LE16，83.33% under prochloraz and 75.93% under 50% LE16 + 50% prochloraz after 15 days storage，respectively. The results demonstrate that self-digestive fermentation liquid of LE16 as a promising biological preservative for the postharvest fruit preservation，can decrease the mycelium growth of P. digitatum and P. italicum and related fruit disease incidence，and the self-digestive fermentation liquid application will partly reduce the use of chemical fungicides without changes in the quality of citrus fruits.

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New Technology & New Method

• Optimization and Validation of PpPDS Gene Silencing Induced by Prunus Necrotic Ring Spot Virus in Prunus persica
• PAN Jiajia, ZHANG Dongmei, MENG Jian, GAO Sunan, ZHU Kaijie, LIU Junwei, LI Guohuai
• Acta Horticulturae Sinica. 2023, 50(7): 1587-1600. DOI:10.16420/j.issn.0513-353x.2022-0484
• Abstract ( 269 ) HTML ( 100 ) PDF (2942KB) ( 100 ) 　　　

• At present，VIGS still works as a main method for gene silencing studies in peach. However，the current VIGS efficiency is low that is urgent to develop a more efficient VIGS system in peach. Using PpPDS（Phytoene desaturase gene）as the indicator gene，the effects of infection mode，viral vector，temperature，age of inoculated seedling and bacterial concentration on the VIGS efficiency in peach leaves，were comprehensively investigated. The results showed that leaf agroinfiltration was an effective way of infection；Prunus necrosis ring spot virus（PNRSV）vectors（pCaRNA1/2 and pCaRNA3）were better than the modified TRV vectors（pTRV1 and pTRV2）of tobacco rattle virus；the infection temperature was better at 22 ℃；peach seedlings with 5-6 fully expanded leaves were higher，reaching 85% of gene silencing efficiency；the bacterial concentration at OD₆₀₀ = 1.0 was better. Based on the optimized parameters of VIGS system，two peach chlorophyll biosynthetic genes（PpGluTR and PpPOR）were selected as target to verify the optimized VIGS system. The results showed that the expressions of PpGluTR and PpPOR were significantly repressed，and the change of leaf color was evident. The studies suggest that the optimized VIGS system has good stability and high silencing efficiency，which can be used for gene silencing studies in peach.

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New Cultivars

• A New Late Ripening Apple Cultivar‘Jiping 5’
• WANG Jinxin, HUANG Jingmiao, HAO Jie, LI Xueying, FENG Jianzhong, SUO Xiangmin, YAN Xinmin
• Acta Horticulturae Sinica. 2023, 50(7): 1601-1602. DOI:10.16420/j.issn.0513-353x.2021-0345
• Abstract ( 316 ) HTML ( 101 ) PDF (2546KB) ( 101 ) 　　　

• ‘Jiping 5’is a new apple cultivar selected and bred by natural hybridization pollination with ‘Changfu 2’as female parent. The tree posture is open，the tree vigor，and has high germination rate and strong branching ability. The fruit shape is ovoid with obvious pentagonal protrusions，and the average fruit weight is 203.8 g. The fruit surface is light green，the flesh is green and white，crisp and juicy，the peel hardness is 9.45 kg · cm^-2，the flavor is sweet，and the soluble solids content is 15.53%. The fruit ripened around 175 d in late October in Shijiazhuang with the same maturity. This cultivar has strong disease resistance，and the yield in 4-5 years of planting can reach up to 37 500 kg · hm^-2.

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• A New Bitter Gourd Cultivar‘Dingfeng 1’
• GUO Jinju, HE Xiaoli, YAO Chunpeng, GONG Hao, HUANG Hexun, ZHANG Changyuan
• Acta Horticulturae Sinica. 2023, 50(7): 1603-1604. DOI:10.16420/j.issn.0513-353x.2021-0196
• Abstract ( 373 ) HTML ( 90 ) PDF (2412KB) ( 90 ) 　　　

• ‘Dingfeng 1’is a new broad-shoulder bitter gourd F₁ hybrid developed by using strong female line D171008 as female parent and inbred line Y172017 as male parent. It has strong vigorous growth potential with dark green leaves. Its fruits are characterized by short conical shape，dark green color and strong luster with about 11.7 cm in length，8.9 cm in transverse diameter, 1.17 cm in flesh thickness and 307 g in the individual fruit weight. It has high commodity rate（93%）and good yield，and the yield is above 21 550 kg · hm^-2. It takes about 72 days from the sowing to the first harvesting in spring，and 59 days in autumn. This cultivar shows strong tolerance to high temperature，waterlogging and drought，moderate resistance to cold. It’s suitable for spring and autumn cultivation in South China.

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• A New Phalaenopsis Cultivar‘Yufen’
• LÜ Fubing, CHEN Heming, LI Zuo, XIAO Wenfang
• Acta Horticulturae Sinica. 2023, 50(7): 1605-1606. DOI:10.16420/j.issn.0513-353x.2021-0293
• Abstract ( 712 ) HTML ( 81 ) PDF (1251KB) ( 81 ) 　　　

• The Phalaenopsis cultivar‘Yufen’with pink flower is bred by crossing female Phal.‘Wedding Promenade’and male Phal.‘Lucky Angel’. The number of pedicels per plant was 1.4，there are 7.8 flowers in the main inflorescence and 12.6 flowers on the whole，the length of flower branches was 38.2 cm，the diameter of flower was 5.3 cm and the flower color is pink with round and good design.

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• A New Ornamental Ailanthus altissima Cultivar‘Liaohong’
• QIU Qiandong, ZHAO Peibao, GUO Shangjing, YU Shouchao, ZHANG Xiusheng, GAO Xiangbin
• Acta Horticulturae Sinica. 2023, 50(7): 1607-1608. DOI:10.16420/j.issn.0513-353x.2021-0339
• Abstract ( 402 ) HTML ( 73 ) PDF (1203KB) ( 73 ) 　　　

• The new Ailanthus altissima cultivar‘Liaohong’was selected from the natural variation of A. altissima plants. The tree crown is semicircular，the annual branches are purple, the ovaries and anthers are orange-red；the young compound leaves are orange-red，the petioles are purplish red；the young samaras are cerise，and the mature samaras are dark red. It is one of the infrequent red fruit series cultivars in summer in current arbor tree species，and has important ornamental value.

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