Abstract:Jinzhongcheng is a new bud sport variety of Changhong Navel Orange[Citrus sinensis(L.)Osbeck]discovered in Baiyangping Village,Guojiaba Town,Zigui County and selected by the breeders at Huazhong Agricultural University.The molecular marker technology was employed to identify the identity.The results confirmed that it was a bud sport of Changhong Navel Orange.The fruit exhibited an oblong-elliptical morphology(fruit shape index＞1.10)and was characterized by vivid,reddish-or-ange rind coloration.With an average fruit weight exceeding 200 g,the fruit demonstrated fine and smoothy oil glands,crispy and tender flesh with excellent juiciness,and a distinctive aromatic profile.The fruits ripened in late November and had excellent storage capability.The fruits displayed distinc-tive morphological characteristics,such as unique tall cylindrical fruit shape and notably larger size compared with its Changhong Navel Orange.The tree exhibited an open growth habit with a natural open-center canopy,demonstrating vigorous growth and producing 3-4 times of shoot growth annually.Jinzhongcheng predominantly bore fruits on leafy shoots,and all the spring,summer,and autumn shoots had the potential to develop into fruitful branches due to their high Flower bud differentiation ability.This cultivar was characterized by broadly lanceolate leaves with distinctive winged petioles,and exhibited a strictly annual flowering cycle.Its flowers consisted of 5 white petals.It demonstrated distinct phenological phases in Zigui County:the budbreak started in early March,followed by spring shoot emergence in mid-to-late March.The flowering commenced in mid-to-late April,reaching full bloom in late April.The fruit underwent two physiological fruit drop phases-the first in early May and the second in mid-to-late May.The summer shoot development occured in mid-to-late May,and the au-tumn shoot development in mid-to-late July.The fruits began color change around mid-September and reached harvest maturity approximately in mid-December.Jinzhongcheng grew well when trained to an open-center form,demonstrating optimal fruit production on spring shoots and early autumn shoots.The post-fruiting magnesium deficiency commonly occurred and required timely supplementation.The fruit quality parameters of Jinzhongcheng were as follows:a long-fruited morphology(fruit shape index 1.42),orange-red rind with tight adherence(difficult to peel),and complete seedlessness.The biochemi-cal analyses revealed its premium quality attributes,including 15.03％soluble solids content,1.29％ti-tratable acidity,average fruit weight of 396.88 g,vitamin C concentration of 58.49 mg·100 g-1 flesh,and 77.41％edible portion.Under containerized cultivation,the trees typically initiated fruit production in the third year,reached commercial yields in the fifth year,with productivity increasing from initial yields of 9000 kg·ha-1 to exceeding 37 500 kg·ha-1 at peak production.Jinzhongcheng exhibited moder-ate resistance to citrus bacterial canker(Xanthomonas citri subsp.citri)and citrus tristeza virus,with no exceptional disease susceptibilities observed under standard cultivation conditions.The primary pest management should focus on controlling aphids(Aphididae),and citrus red mites(Panonychus citri).Originally developed in Hubei Province,this cultivar showed optimal adaptation to navel orange pro-duction regions across Hubei and other ecologically comparable areas with similar conditions.

Abstract:[Objective]Malus sieversii is a significant wild fruit tree resource in the arid regions of Cen-tral Asia and the ancestral species of modern cultivated apples.The leaf chlorophyll content of M.siev-ersii normally serves as a key indicator reflecting its photosynthetic capacity and overall health status.To meet the demands of nutritional status and diseases monitoring of M.sieversii,this study established a non-destructive and rapid monitoring method for chlorophyll content in the canopy of M.sieversii us-ing a high-spectrum unmanned aerial vehicle(UAV)coupled with machine learning algorithms based on integrated spectral preprocessing techniques.The optimal machine learning model was selected to in-vert the SPAD values in the research area.[Methods]The experimental area selected the Saha Wild Fruit Forest in Xinyuan County,Hi River Valley,Xinjiang,which has typical distribution characteris-tics.During the flowering period of wild apples,the DJI M350RTK UAV was equipped with the Ga-iaSky-mini3-VN hyperspectral imaging system to obtain hyperspectral images of the canopy in the study area.Meanwhile,the relative chlorophyll contents of 85 sample tree canopies were synchronously measured using the SPAD-502Plus chlorophyll meter.During data processing,the first part of the bands with large noise(399.08-409.27)was removed.Subsequently,spectral optimization were then per-formed using eight preprocessing schemes,including four basic preprocessing methods(Savitzky-Go-lay smoothing(SG),multiplicative scatter correction(MSC),standard normal variate transformation(SNV),and moving average smoothing(MA))and their combinations with first derivative transforma-tion(D1).On this basis,three types of hyperspectral narrow-band vegetation indices were systematical-ly constructed:difference spectral index(DSI),ratio spectral index(RSI),and normalized difference spectral index(NDSI).Four algorithms,namely random forest regression(RFR),XGBoost,gradient boosting decision tree(GBDT),and K-nearest neighbor regression(KNN),were used to establish chlo-rophyll content inversion models,and the coefficient of determination(R2)and root mean square error(RMSE)were used as evaluation indicators.[Results]Spectral analysis showed that the canopy spec-trum of wild apples exhibited a reflection peak near 550 nm and a distinct chlorophyll absorption valley at 680 nm,with a steep increase in reflectance in the red edge region(700-750 nm).Without the basic preprocessing step of derivative transformation,Random Forest Regression(RFR)standed out as the best-performing preprocessing model,with an average test set R2 of 0.746(RMSE=2.707).Its advantag-es were particularly pronounced in scatter correction preprocessing,where the R2 values of MSC-RFR and SNV-RFR attained 0.772 and 0.775,respectively.The SG-D1 preprocessing method significantly re-duced the influence of high-frequency noise on the spectrum without damaging the effective spectral in-formation.Among them,MA-D1-NDSI(580.43,447.92)exhibited a correlation coefficient of 0.75(P＜0.01)with wild apple SPAD values,significantly outperforming other preprocessing methods.The char-acteristic bands were predominantly distributed in the red edge region(680-750 nm)and the near-infra-red plateau region(760-900 nm).Comparative results of the four machine learning models indicated that the RFR model exhibits the best predictive performance.Particularly under the SG-D1 preprocess-ing condition,this model achieved the R2 value of 0.818 with the RMSE of 2.419,representing a 5.5％improvement in accuracy compared to the best model of basic preprocessing(SNV-RFR).In contrast,the predictive accuracy of the XGBoost(R2=0.725),KNN(R2=0.729),and GBDT(R2=0.645)models de-creased in sequence,among which the GBDT model exhibited significant overfitting.Based on the opti-mal SG-D1-RFR model,this study generated a spatial distribution maps of the SPAD values of the M.sieversii canopy in the study area.The inversion results showed that the SPAD value of the M.sieversii canopy in the study area ranged from 17.1 to 39.8,exhibiting a distribution pattern that is higher in the southeast and lower in the northwest.Furthermore,the model could effectively distinguish plants with different health status:The SPAD values for healthy canopies clustered between 30 and 36,while those of stressed or senescent canopies predominantly exhibited values below 25.Moreover,the model suc-cessfully identified shadow areas(SPAD＞35)and dead branch areas(SPAD＜18)within the trees,vali-dating its applicability under complex canopy conditions.[Conclusion]The SG-D1 preprocessing method significantly enhanced the red-edge features and improved the correlation between spectral in-formation and chlorophyll content.The RFR algorithm performed outstanding in handling high-dimen-sional spectral features,making it the optimal choice for chlorophyll inversion of M.sieversii leaves.The constructed NDSI,RSI,and DSI indices can effectively capture the variations in chlorophyll con-tent.This method provides a novel technique for non-destructive monitoring of wild fruit tree resources,and its technical route can also be extended to the remote sensing monitoring of physiological parame-ters of other woody plants.By systematically investigating the influence of eight spectral preprocessing methods on the inversion of chlorophyll content in the canopy of M.sieversii,we proposed the optimal model combination of SG-D1-RFR and established a spectral index system suitable for complex canopy structures.Furthermore,this methodology can be applied to the monitoring and conservation of other endangered wild fruit tree resources.These studies further refine the theoretical framework and techni-cal methods for remote sensing monitoring of wild plant resources.

Abstract:As China's most significant fruit crop,apple leads the world in both cultivation area and pro-duction,and have long been the country's top fruit export.Aroma serves as a crucial indicator for senso-ry evaluation and a key determinant of intrinsic fruit quality.The interplay between aromatic compo-nents and fruit characteristics including sugar contents and acidity collectively determines apple flavor profiles.Currently,China has developed numerous apple cultivars,yet few exhibit comprehensive excel-lent traits and are widely cultivated.The field still faces challenges such as monotonous breeding objec-tives,and severe lag in high-efficiency breeding technologies like molecular marker-assisted selection and genetic engineering.This paper systematically elaborates on the composition of volatile compounds in apple fruit,their biosynthetic pathways,genetic characteristics,and localization of key genes,aiming to provide a theoretical foundation for molecular marker-assisted selection of new apple cultivars with distinctive aromas and superior comprehensive traits.Since the mid-20th century,Chinese scientists have systematically explored apple aroma.Early studies primarily focused on identifying volatile com-pounds produced during apple ripening.After the 1990s,advancements in analytical instruments and scientific technologies enabled investigations into the biosynthesis and regulatory mechanisms of apple aroma compounds.Over 300 volatile compounds have been identified in apples,with 20-30 key com-pounds primarily contributing to the characteristic fragrance,predominantly consisting of esters,alco-hols,aldehydes,ketones,and terpenes.Characteristic aroma compounds are defined by their significant contribution to fragrance,which is determined by their specific composition,concentration,detection thresholds,and synergistic interactions.The predominant characteristic aroma compounds in apples in-clude butyl acetate,hexyl acetate,butyl butyrate,2-methylbutyl butyrate,hexyl butyrate,1-butanol,1-hexanol,hexanal,α-farnesene,etc.Distinct molecular structures confer unique aromatic properties.Es-ters typically exhibit"sweet and fruity"notes,while aldehydes,alkenes,and alcohols predominantly contribute"green and grassy"aromas characteristics.Apple aroma biosynthesis primarily occurs through three metabolic pathways,such as fatty acid metabolism pathway,amino acid metabolism path-way,and terpenoid metabolism pathway.The major unsaturated fatty acids involved in the synthesis of volatile substances via fatty acid pathway include stearic acid,oleic acid(OA),linoleic acid(LA)and α-linolenic acid(ALA).Most aroma compounds in apples are synthesized through fatty acid metabolism,which mainly occurs via two pathways,β-oxidation and the lipoxygenase(LOXs)pathways.The β-oxi-dation pathway primarily degrades stearic acid,OA,and ALA,at the same time forming substantial amounts of acetyl-CoA,which is a crucial precursor for ester biosynthesis from alcohols.Following β-oxidation,the LOX pathway produces most aroma compounds in fruits,and is closely associated with the formation of ester compounds.In the amino acid metabolic pathway,the amino acids involved in aroma synthesis include valine,leucine,isoleucine,alanine,cysteine,and phenylalanine.These contrib-ute to the characteristic apple flavor by forming branched-chain esters.Terpene compounds are the larg-est class of floral volatiles in plants.The terpenes contained in apple volatile substances include α-farne-sene,trans-β-farnesene and α-acacene.The synthesis of terpenoids in apple mainly occurs through two pathways:the mevalonic acid pathway(MVA pathway)and the methyl-D-erythritol-4-phosphate path-way(MEP pathway).The precursors of the two pathways are isopentenyl pyrophosphate(IPP)and di-methylallyl pyrophosphate(DMAPP),respectively.In MVA pathway,the precursor IPP undergoes enzy-matic reaction to produce the intermediate product farnesyl pyrophosphate(FPP),which finally synthe-sizes sesquiterpenoids or triterpenoids under the action of various terpenoid synthases.The MEP path-way is precursors of pyruvate and glyceraldehyde 3-phosphate.IPP and DMAPP are produced through 7 enzymatic reactions.DMAPP produces hemiterpenes,monopterpenes and multiple polyterpenes through different pathways.Among the volatile substances in the hybrid offspring of Fuji × Pink Lady,the characteristic aroma substances in apple such as hexyl acetate,2-methylhexyl butyrate,hexyl capro-ate,hexal,2-hexenal,and α-farnene have typical quantitative trait genetic characteristics.In the F1 gen-eration,the mean values of these six aroma substances are all higher than the mid-parent value,dislay-ing an addtive genetic effect.And more than half of the esters show superherophilic phenomena.In the progeny,hexaldehyde,2-hexenal and α-farnene showed positive transgressive segregation,displaying obvious heterosis.The mean values of hexyl acetate,butyl butyrate,hexyl butyrate,butyl caproate and n-hexanol in the offspring of F1 generation of Fuji × Golden Crown are all higher than the parent values,showing a relatively high transgressive inheritance.The mean values of the progeny of 2-methylbutyl-hexanoate,hexal,2-hexenal and a-farnene were higher than the mid-parent value.In F1 progeny fruit of Honeycrisp × Qinguan,most ester substances such as hexyl acetate,butyl butyrate,hexyl caproate,and hexyl butyrate,as well as e-2-hexenal and a-farnene,showed an negative transgressive segregation.Hexaldehyde exhibits a moderately negative transgressive inheritance.The same aroma substance in ap-ple fruit shows different separation pattern in the offspring of different hybrid combinations.It may be affected by environmental factors or have gene interactions or recessive synergistic genes,resulting in the occurrence of positive transgressive segregation in the F1 generation.Currently,through the con-struction of QTL genetic mapping,candidate genes of LOXs,HPL,ADH and AAT,which are key genes for aroma synthesis,have been identified in apples,grapes and jujubes.Notably,MdLOX1a and MdAAT are functionally linked to the biosynthesis of characteristic aroma esters in apples.Dunemann F.mapped a candidate gene of MdLOX on LG9.HPL has been proved to be involved in the synthesis of al-dehydes in fruits,and ZjHPL in jujube may be the key gene involved in(E)-2-hexenal synthesis in ju-jube.The candidate genes of MdADH and MdAAT have been identified on LG2 and MdAAT6 on LG6.This review systematically elucidates the composition,biosynthetic pathways,genetic characteristics,and key gene localization of apple volatile compounds,in order to provide insights into precise aroma phenotyping and genotyping,and to provide reference for the marker-assisted selection of new apple va-rieties with characteristic aroma and excellent comprehensive characteristics.

Abstract:[Objective]This study aimed to explore the effects of different storage temperatures on the quality and metabolic changes of fresh macadamia(Macadamia spp.)nuts,elucidating the mechanisms by which storage temperature influences the physiological metabolism of the nuts,thereby providing a theoretical basis for extending the shelf life of fresh macadamia nuts and maintaining its post-harvest quality.[Methods]In this experiment,fresh green-peel kernels(XQ)and shelled kernels(XK)were used as the main test materials,which were packaged in PE bags and stored under different tempera-tures(25℃,4℃,-18℃),and divided into 6 groups:25XQ,4XQ,-18XQ,25XK,4XK,-18XK,and samples were taken after 0,7,14,21,28,35,and 42 days of storage.The moisture content,protein con-tent,crude fat content,color difference,energy metabolism level,polyphenol oxidase(PPO),peroxi-dase(POD),superoxide dismutase(SOD),catalase(CAT)enzyme activities,and malondialdehyde(MDA)content were determined.Experimental data were collected and collated by Microsoft Excel 2016,graphed with Origin 2022,and one-way analysis of variance(ANOVA)was performed with SPSS 27.0 software(P＜0.05).[Results]The results showed that 4℃ was the optimal temperature for preserving the moisture content,crude fat content,and protein content of fresh macadamia kernels.On day 0,the kernels exhibited a relatively high initial moisture content(approximately 23.43％),with crude fat and protein contents of about 59.34％and 6.13％,respectively.When stored at room tempera-ture(25℃),the crude fat content of 25XQ ranged from 58.80％to 61.73％,while its protein content varied between 6.04％and 6.38％.For 25XK,the crude fat content ranged from 59.34％to 72.15％,and the protein content ranged from 6.13％to 7.45％.In contrast,under 4℃ storage,the crude fat and pro-tein contents ranged from 59.34％to 62.05％and 6.13％to 6.41％,respectively.Similarly,4XK main-tained crude fat content between 59.34％and 64.34％,and protein content between 6.13％and 6.65％.Meanwhile,4℃ proved to be a more effective method for preserving the color of both XQ and XK ker-nels.The color difference(⊿E)of-18XQ was significantly higher than those of 25XQ and 4XQ(P＜0.05),indicating greater changes in appearance color under-18℃ compared with storage at 25℃ and 4℃.Similarly,the ΔE value of 25XK was significantly higher than those of 4XK and-18XK(P＜0.05).Storage at 4℃ enabled better preservation of the energy metabolism in both XQ and XK kernels.Compared with those stored at 25℃ and-18℃,the ATP content,ADP content,and energy charge of kernels kept at 4℃ consistently maintained at relatively higher levels.The treatment of storage at 4℃and-18℃ reduced POD activity in macadamia,significantly inhibiting the degradation of hydroperox-ides derived from unsaturated fatty acids and thereby decreasing the formation of off-flavors.Besides,4℃ significantly reduced the PPO activity and delayed the browning of macadamias.Furthermore,4℃ was more helpful to maintain the activity of SOD and CAT.The SOD and CAT activities of 4XQ and 4XK were significantly higher than those of 25XQ,25XK,-18XQ and-18XK(P＜0.05).The syn-ergistic action of SOD and CAT efficiently eliminated reactive oxygen species(ROS),reduced oxida-tive damage to the membrane system.Storage at 4℃ effectively delayed the rate of MDA generation by maintaining higher activities of SOD and CAT.[Conclusions]Storage at 4℃ could effectively maintain the moisture content of the macadamia,inhibit the increase of color difference values,and sus-tain a high energy charge state,thus ensuring the ATP-dependent repair mechanisms.Additionally,4℃could maintain quality by reducing the activities of PPO/POD,sustaining high activities of SOD/CAT,and ensuring a stable energy supply.Therefore,4℃ seems to be the optimal storage temperature for fresh macadamia nuts.

Abstract:[Objective]Grape,as an important cash crop widely cultivated in the world,is not only the core raw material for winemaking and the fresh food industry,but also one of the key pillars of China's agricultural industrial structure upgrading and rural revitalization strategy.Northwest China has become a core production area for high-quality grapes by virtue of its unique climatic conditions,with abundant light,significant temperature differences between day and night,and dry air.However,the frequent oc-currence of extreme drought events in the region and the extremely serious problem of water shortage have exacerbated the contradiction between water supply and demand in grape growing.In order to effi-ciently utilize water resources,many different irrigation methods have emerged,and the main irrigation methods currently used for crops are diffuse,furrow,sprinkler,drip and seepage irrigation.Different irri-gation methods have a great impact on viticulture.For this reason,it is important to study the effects of different irrigation methods on grapevines under different irrigation levels to provide theoretical support for viticulture and water-saving irrigation models in the arid regions of Northwest China.[Methods]Two-year old Nantaihutezao grapes were used as experimental materials,four treatments were set up,namely,conventional drip irrigation(DI)(30 min,3.6 L),100%RTI(30 min,3.6 L),75%RTI(22.5 min,2.7 L),and 50%RTI(15 min,1.8 L),to study the water movement pattern,root vigor,root anatomy,and soil alkaline nitrogen,effective phosphorus,quick phosphorus,and soil water content of the soil in different soil layers(0-60 cm)of the different irrigation treatments.The effects of different irrigation treatments on water movement,root vigor,root anatomical structure and soil content of different soil layers(0-60 cm)were investigated.[Results](1)The results of water movement pattern showed that under DI treatment,water was mainly concentrated in the soil surface layer(0-20 cm),while the RTI treatment led to better distribution of soil moisture content in the deeper layer than DI by directly trans-porting water to the distribution area of grapevine root system(near the soil layer of 20 cm),and then rapidly infiltrating downward with the water.(2)The results of root vigor showed that the root vigor un-der different irrigation treatments was significantly different.There was a significant difference,in which the root vigor under 100%RTI was significantly higher than that of DI,which was 1.23 times higher than that of DI;the root vigor under 75%RTI was much similar to the results of DI.(3)The re-sults on root anatomical structure showed that the root xylem conduit density and conduit diameter pro-duced significant changes under different irrigation treatments,in which the conduit density under 75%RTI and 50%RTI was 25%and 100%higher than that of DI,respectively,while the average conduit di-ameter showed the opposite trend,with the mean conduit diameters under 75%RTI and 50%RTI being 19%and 97%lower than that of DI,respectively;(4)The results on soil nutrients showed that there were significant differences in the vertical distribution of soil nutrients under different irrigation treat-ments.The DI treatment resulted in significant enrichment of nutrients in the 0-20 cm surface layer of the soil,where alkaline dissolved nitrogen,effective phosphorus,quick potassium,and organic matter contents were 1.54-3.10 times higher than those of the RTI treatment,but the deeper layers(30-60 cm)had lower nutrient contents than those of the RTI treatment as a whole.The RTI drove nutrients through directional water transport,and the RTI drove the nutrients to the intensive root distribution area(20-40 cm)through directional water transport,in which the contents of alkaline dissolved nitrogen,effec-tive phosphorus,quick-acting potassium and organic matter in the 20-60 cm soil layer under the 100%RTI treatment were 1.19-1.34 times higher than those in the DI treatment,and the contents of alkaline dissolved nitrogen,effective phosphorus and organic matter in the 20-60 cm soil layer under the 75%RTI treatment were much similar to those in the DI treatment.[Conclusion]The RTI improved the plant water and fertilizer utilization by changing the water movement pattern,affecting root vigor,opti-mizing root conduit structure and improving the vertical distribution of nutrients in the deep soil layer,and the mode of"reducing depletion in the surface layer and increasing storage in the deep layer"of RTI reduced the loss of nutrients caused by evaporation and runoff,and strengthened the drought-resis-tant ability of the plant and improved water utilization efficiency.The RTI model of"surface reduction and deep storage"could reduce the nutrient loss caused by evaporation and runoff,enhance the drought resistance of plants and improve the water utilization efficiency,which would provide a theoretical ba-sis for the precision irrigation technology of grapevine in arid areas.

Abstract:[Objective]The study aimed to systematically evaluate the regulatory effects of different plant growth regulators on quality formation during the fruit development of Yanfu No.3 apple,and to elucidate their physiological impacts on fruit appearance characteristics,nutritional quality,and aroma substance formation.[Methods]The experiment was conducted in the main apple-producing area of Jingning County,Gansu Province,using widely cultivated 6-year-old Yanfu No.3(Malus domestica Bork.)apple trees as research material.Treatments were applied at the young fruit stage,approximately 20 days after flowering,using a randomized block design with seven spray treatments:T1(gibberellin GA4),T2(gibberellin GA7),T3(spraying gibberellin GA4+7 compound),T4(chlorogenic acid),T5(sodi-um nitrophenolate),T6(gibberellin(GA4+7)+sodium nitrophenolate),T7(gibberellin(GA4+7)+sodium nitrophenolate+chlorogenic acid).water spray treatment served as the control(CK).Each treatment was replicated three times.All treated trees received unified water and fertilizer management,pest and disease control,and pruning techniques to minimize interference from non-experimental factors and en-sure the feasibility of the experimental data.The full-bloom date of Yanfu No.3 apple is April 28,and the fruits are ripe and harvested on October 22,which is 170 days after full bloom,and relevant indica-tors were immediately tested and analyzed.Appearance characteristics included fruit weight and fruit shape index;internal quality indicators included the contents of vitamin C,total phenols,total sugars,soluble solids,soluble protein,flavonoids,and tannins in the fruits.[Results]The research results showed that all different spray treatments affected the quality formation of Yanfu No.3 apple fruits,with significant differences observed among treatments for the various indicators.Although single regu-lator treatments performed well in certain individual indicators,the combination treatments demonstrat-ed superior comprehensive regulatory effects.Notably,the T7 treatment(GA4+7+chlorogenic acid+so-dium nitrophenolate)showed significant advantages in enhancing fruit nutritional components.The fruits under T7 treatment exhibited significantly higher contents of vitamin C,total sugars,soluble sol-ids,and soluble protein compared with other treatments and the control,indicating a strong synergistic effect of the regulator complex in promoting nutrient accumulation.In addition,T7 treatment signifi-cantly reduced the contents of flavonoids and tannins in the fruits and effectively improved their flavor.Regarding appearance characteristics,the fruits from T3 and T7 treatments showed better shape indices.The analysis identified the main aroma components of Yanfu No.3 apples as esters,alcohols compo-nents.The T7 treatment was particularly effective,resulting in the fruits exhibiting a more intense over-all aroma.The underlying mechanism would be presumed to be related to the regulators promoting the synthesis and conversion of aroma precursors and enhancing fatty acid metabolism and related enzyme activities,thereby increasing the accumulation level of volatile aroma compounds.[Conclusion]Based on the systematic analysis of the appearance characteristics,nutritional quality,and aromatic com-pounds of the Yanfu No.3 fruits in this experiment,it can be concluded that the application of 10 mg·L-1 gibberellic acid GA4+7 plant growth regulators and 12 mg·L-1 gibberellic acid(GA4+7)+sodium nitro-prusside+chlorogenic acid plant growth regulators had a positive effect on improving the fruit quality of Yanfu No.3 in the Loess Plateau region,with the T7 treatment showing the most significant effect.

Abstract:[Objective]This research investigated the variation in tannin and other phenolic compounds in the kernel pellicle of different walnut(Juglans regia L.)cultivars,aiming to elucidate the mecha-nisms underlying their biosynthesis and accumulation as well as to provide a theoretical foundation for targeted improvement of quality traits related to phenolic composition in walnut.[Methods]Three wal-nut cultivars exhibiting distinct tannin levels were selected,including low-tannin Bingta No.1(BT-1),medium-tannin Wen 185(W-185),and high-tannin Zha 343(Z-343).Fruits were collected from five-year or older,vigorously growing trees under consistent water and fertilizer management at the XPCC(Xinjiang Production and Construction Corps)walnut germplasm repository(40°23′N,80°03′E).Sam-pling occurred at eight critical developmental stages:T1(June 12),T2(June 18),T3(June 28),T4(July 5),T5(July 15),T6(July 25),T7(August 9),and T8(August 24).Fresh seed coats were fixed in FAA for paraffin sectioning.Sections were dehydrated through graded ethanol solutions,cleared in xylene,embedded in paraffin,and stained with safranin-fast green.Tannin cells were specifically identified by the purple-red coloration resulting from the safranin-tannin reaction,observed and photographed using optical microscopy.Tannin spatial distribution during development was visualized via imprint staining.Fresh fruit cross-sections were pressed onto a piece of filter paper,which formed purple imprints due to oxidative property of tannins.Total tannin content was determined spectrophotometrically using Folin reagent with gallic acid as standard.Total phenolic content was assayed using the Folin-Ciocalteu meth-od(gallic acid equivalent).Total flavonoid content was determined by the aluminum nitrate colorimet-ric method(rutin equivalent).Phenolic composition was analyzed by HPLC using an Agilent TC-C18(2)column(250 mm×4.6 mm,5 μm)at 35℃.The mobile phase consisted of(A)50%methanol and(B)0.2%aqueous acetic acid,with a gradient elution(A:8%to 40%from 0-40 min,then back to 8%).Flow rate was 0.8 mL·min-1,and injection volume 10 μL.Detection was at 280 nm.Six phenolic acids(shikimic,gallic,caffeic,vanillic,chlorogenic,and p-coumaric)and four flavonoids(catechin,epicate-chin,rutin,and myricetin)were quantified using external standards.[Results]The tannin content in the kernel pellicle of all three cultivars exhibited a pattern of"decline-rise-decline"during fruit develop-ment.Significant differences(P＜0.05)were observed in the timing of key fluctuation nodes and peak accumulation intensity.Peak concentrations were 352.75 mg·g-1,386.84 mg·g-1,and 448.99 mg·g-1for BT-1,W-185 and Z-343.BT-1 accumulated significantly less tannin than W-185 and Z-343 at peak.Im-print staining confirmed tannin deposition was localized specifically within the seed coat,with staining intensity following a"light-dark-light"trend with fruit maturation.Paraffin section revealed that tannin accumulation was primarily associated with specialized tannin cells surrounding the vascular bundles.These cells function as key sites for tannin synthesis,storage,and transport.Cultivars differed markedly in tannin cell abundance and activity.During peak accumulation,W-185 and Z-343 possessed numer-ous,metabolically active,densely packed tannin cells,whereas BT-1 had fewer such cells.This results agreed with the lower tannin synthesis rate and content observed in BT-1.HPLC analysis revealed shi-kimic acid as the predominant phenolic acid and epicatechin as the major flavonoid across cultivars,with distinct accumulation dynamics.BT-1 exhibited significantly lower levels of shikimic acid,gallic acid,p-coumaric acid,and epicatechin compared toW-185/Z-343;Shikimic,vanillic,and chlorogenic acids accumulated continuously,while caffeic acid declined steadily.In Z-343,chlorogenic acid content increased markedly at T5 stage(from 28.32 to 76.29 mg·g-1);rutin accumulated continuously,peaking at 10.54 mg·g-1.In BT-1,a sharp transient increase in rutin was observed at T3 stage.Pearson correla-tion analysis revealed cultivar-specific regulatory networks linking tannins to other phenolics.In BT-1,tannin positively correlated with p-coumaric acid and epicatechin,but negatively correlated with rutin and total flavonoids;in W-185,tannin showed an extremely significant positive correlation with gallic acid(P＜0.01),but negative correlations with caffeic acid and total phenolics;in Z-343,tannin correlat-ed positively only with total phenolics and caffeic acid,but negatively with most phenolic acids.These distinct correlation patterns indicate that variation in partitioning of phenylpropanoid metabolic flux,mediated by differential precursor supply(e.g.,shikimic acid)and the balance of competitive metabo-lites(e.g.,rutin vs tannin precursors),is a critical factor driving divergent tannin accumulation strategies among cultivars,and ultimately influences tannin biosynthetic efficiency.[Conclusion]Tannin accumu-lation in walnut kernel pellicle is co-regulated by cellular structural morphology and phenolic biosynthe-sis pathways.The low tannin phenotype of Bingta No.1(BT-1)results from:(1)a reduced number of tannin cells,limiting synthesis capacity;(2)diminished accumulation of key precursors like shikimic ac-id;and(3)competitive metabolic flux towards rutin synthesis,potentially diverting substrates away from the tannin pathway.In contrast,cultivars Wen 185(W-185)and Zha 343(Z-343)achieve higher tannin accumulation through more abundant tannin cells and enhanced provision of precursors,such as chlorogenic acid in Z-343 and gallic acid in W-185.The identified differentiation in phenolic metabo-lism provides a biochemical basis for targeted regulation of tannin synthesis.As an excellent low-tannin germplasm,Bingta No.1 possesses unique metabolic characteristics valuable for dissecting the molecu-lar mechanisms controlling tannin biosynthesis.Future research should employ multi-omics technolo-gies to identify key regulatory genes within these pathways,enabling precision breeding or biotechno-logical approaches to modulate astringency and improve walnut quality.

Abstract:[Objective]Ziziphus jujuba Mill.,a hallmark fruit crop in China,holds significant economic and cultural value due to its dual utility for fresh consumption and drying.However,the rapid posthar-vest quality deterioration of fresh jujube limits its market circulation and storage duration.The physio-logical changes and nutrient retention in fruits postharvest are profoundly influenced by maturity stages,making the determination of the optimal harvest period a critical issue for balancing fruit quality,stor-ability,and commercial value.Tayou 12,a superior line derived from seedling progeny of the Tailihong jujube,stands out for its stable yield,high productivity,intense sweetness,and large fruit size.Despite its outstanding agronomic traits,systematic studies on the postharvest quality dynamics of its fruit at dif-ferent maturity stages remain scarce.This research aims to elucidate quality changes during ambient storage of Tayou 12 fruits at varying maturity stages,and to provide reference for precise harvest tim-ing.[Methods]Fruits at three maturity stages,including white-ripe stage(＜5%reddening,green-white peel,crisp texture),half-red stage(50%-70%reddening,transitional green-red coloration),and full-red stage(＞95%reddening,physiological maturity with complete sugar accumulation),were stud-ied.For each stage,20 kg of intact,undamaged,disease-free fruits were stored in ventilated plastic crates at 25±1℃and 75%±5%relative humidity.Daily sampling was conducted to assess water loss(gravimetric method,%),firmness(TMS-PRO texture analyzer,N),total phenolics(Folin-Ciocalteu method,mg·g-1),flavonoids(aluminum nitrate-sodium nitrite colorimetry,mg·g-1),vitamin C(2,6-di-chloroindophenol titration,mg·100 g-1),malondialdehyde(spectrophotometry,μmol·100 g-1),respira-tion rate(closed-system gas chromatography,mg·kg-1·h-1),decay rate(visual inspection,%),organic ac-ids,and sugar profiles(HPLC,mg·g-1).[Results]During storage,the sensory evaluation of fruits at dif-ferent maturity stages showed significant differences.The total evaluation score of the white-ripe stage was the highest at 25.3 points on the 4th day;the half-red stage(26.4 points)and the full-red stage(28.9 points)both had the highest total scores on the 1st day.After 9 days of storage,fruit at full-red stage showed the best sensory evaluation during the storage period,making it suitable for fresh consumption.After harvest,the white-ripe and half-red stage fruits increased in the red area of the peel with the in-crease of storage time.The half-red stage fruits turned completely red on the 7th day,indicating that the post-harvest ripening process of immature jujube fruits continued.During storage,the firmness of ju-jube fruits at different maturity stages decreased.The white-ripe stage fruits had the highest initial firm-ness(9.35 N)and the greatest degree of decline.The firmness of the full-red fruits decreased to 5.92 N on the 7th day.The firmness of the half-red stage jujube fruits was between those of the white-ripe fruits and full-red fruits.The full-red fruits had the highest initial respiration rate(35.50 mg·kg-1·h-1),which was 2.24 times that of the white-ripe fruits(15.89 mg·kg-1·h-1)and 1.67 times that of the half-red fruits(21.28 mg·kg-1·h-1),reflecting vigorous metabolic activities.However,during storage,the respira-tion rate of the full-red fruits showed a significant downward trend,and became lower than that of the half-red fruits from the 5th day.The white-ripe and half-red fruits both showed respiration peaks during storage,and they had no significant difference in initial respiration rate and final respiration rate,indi-cating that immature fruits could maintain metabolic vitality during post-harvest storage.The water loss rate during storage increased with the increase of maturity:white-ripe stage(2.73%on the 9th day of storage)＜half-red stage(3.57%)＜full-red stage(4.92%),which was related to the stomatal density and cuticle thickness of the peel.The full-red fruits deteriorated rapidly,with a decay rate of 21.9%on the 4th day of storage,mainly due to peel softening and a decrease in the content of antibacterial substanc-es.The white-ripe fruits had significantly higher initial contents of total phenols(7.63 mg·g-1),flavo-noids(5.95 mg·g-1),and vitamin C(286.59 mg·100 g-1),which might be related to the active synthesis of phenolic substances in the early stage of maturity.The sugar composition in jujube fruits varies with ripeness.In fruits at white-ripe stage,fructose and glucose accounted for a larger proportion,while in the half-red and full-red fruits,sucrose was the dominant sugar component.The total sugar content in the white-ripe fruits showed increased first and then decreased;in the half-red fruits total sugar present-ed a trend of increasing first,then decreasing and increasing again;and in the full-red fruits displayed a gradual increasing trend.The order of total sugar content among different stages was full-red stage＞half-red stage＞white-ripe stage.Specifically,the total sugar content in the white-ripe fruits reached the maximum on the 3th day(233.04 mg·g-1).In the half-red fruits,it increased significantly to 362.78 mg·g-1 on the 9th day.In the full-red fruits,the total sugar content rose significantly to 403.65 mg·g-1 on the 8th day.The major acids in the fruit included citric acid,tartaric acid and malic acid.During storage,the acid content in the full-red fruits showed constantly increased,and was generally higher than that in the white-ripe and half-red fruits.[Conclusions]This study systematically reveals the postharvest quali-ty changes in"Tayou 12"jujube at maturity stages during storage.The half-red fruits proved to be opti-mal for harvest,balancing nutrient retention(high antioxidants,balanced sugars),acceptable firmness(6.78 N at day 9),and moderate decay resistance(23.33%decay at day 9).White-ripe fruits are suitable for long-distance transportation or long-term storage;however,their low sugar content and rapid loss of nutrients restrict the fresh-eating quality.Full-red stage is ideal for immediate consumption or process-ing but requires strict logistics due to poor storage performance.These findings provide a scientific framework for precision harvesting tailored to end-use purposes.Future research should explore con-trolled atmosphere storage technologies to extend the shelf life of fruit at half-red stage,so as to maxi-mize commercial benefits and consumer satisfaction.

Abstract:[Objective]The aim of this study was to investigate the effects of exogenous N-carbonyloc-tanoyl homoserine lactone(3OC8-HSL)on salt tolerance of Malus robusta seedlings by evaluating growth performance,physiological parameters,and the expression of salt-responsive genes under salt stress.[Methods]A greenhouse pot experiment was conducted with four treatment groups:Including the control group(CK,0 mmol·L-1 NaCl+water),the 3OC8-HSL treatment group(AC,0 mmol·L-1 NaCl+10 μmol·L-1 3OC8-HSL),salt stress group(Salt,200 mmol·L-1 NaCl+water),and 3OC8-HSL+salt stress group(AS,200 mmol·L-1 NaCl+10 μmol·L-1 3OC8-HSL).Each treatment was applied to the seedlings for 45 days.3OC8-HSL solution(10 μmol·L-1)was drench-applied to the root zone on days 1,7,and 14,while salt stress was imposed by watering with 200 mmol·L-1 NaCl every 3 days.The growth parameters(plant height and fresh mass)were measured at the end of the experiment.The leaf chlorophyll content was determined(total chlorophyll,as well as chlorophyll a and b)as an indicator for photosynthetic status.The malondialdehyde(MDA)content in seedling roots was quantified to as-sess lipid peroxidation(oxidative stress damage).The leaf Na+and K+concentrations were measured,and the Na+/K+ratio was calculated to evaluate ionic homeostasis under each treatment.For molecular analysis,the root samples from salt-stressed seedlings with and without 3OC8-HSL were subjected to RNA sequencing(RNA-seq).Differentially expressed genes(DEGs)between the AS treatment and Salt treatment were identified using DESeq2(standard:|log2 fold change|＞1 and adjusted p-value＜0.05).The gene Ontology(GO)enrichment analysis was performed to characterize the biological processes en-riched among these DEGs.Furthermore,four DEGs associated with stress responses were selected for validation by quantitative real-time PCR(RT-qPCR):MdPAL,MdGST,MdHKT1,and MdLRR-RLK.[Results]The Growth and Physiological Responses:Under non-saline conditions,the exogenous 3OC8-HSL markedly promoted the growth of Malus robusta seedlings.The treated seedlings exhibited a 23.74%increase in plant height and a 17.23%increase in fresh mass compared with the untreated con-trols,along with a slight but significant rise in the leaf chlorophyll content(+4.06%).These results in-dicated that 3OC8-HSL itself had a growth-promoting effect even without stress.Under salt stress(200 mmol·L-1 NaCl),3OC8-HSL application substantially improved seedling performance and stress tolerance.The 3OC8-HSL-treated salt-stressed seedlings grew taller(+11.61%plant height)and heavier(+26.38%fresh mass than those under salt stress alone.Notably,3OC8-HSL alleviated salt-induced damage:the treated seedlings maintained significantly higher chlorophyll levels(total chlorophyll+36.98%vs salt control),indicating better photosynthetic capacity under stress.In addition,3OC8-HSL reduced oxidative damage,as evidenced by a 36.20%reduction in root MDA accumulation under salt stress relative to untreated seedlings.This lower MDA level suggested that 3OC8-HSL would enhance the antioxidant defense,thereby protecting cellular membranes from peroxidation damage caused by salt stress.The Ion Homeostasis:3OC8-HSL also improved ionic balance in Malus robusta under salini-ty.In the salt-stressed seedlings,3OC8-HSL treatment led to significantly lower Na+accumulation and higher K+retention in plant tissues.Specifically,the Na+content in the 3OC8-HSL-treated seedlings was 11.01%lower than that in the untreated salt-stressed controls,while the K+content was 19.46%higher.Consequently,The Na+/K+ratio,a key indicator of ion homeostasis under salt stress,was re-duced by 22.17%in the 3OC8-HSL group compared with the salt treatment alone.This improvement in Na+/K+homeostasis reflected a better maintenance of ionic equilibrium,which is crucial for salt toler-ance.The results suggested that 3OC8-HSL would help seedlings limit sodium uptake or transport and/or enhance potassium uptake,thereby mitigating ion toxicity under high salinity.Consistently,the treat-ed seedlings showed healthier morphology and less salt injury than the untreated ones(greener leaves,less wilting),as observed qualitatively during the experiment.The Gene Expression and Pathway Acti-vation:The transcriptome profiling of roots under salt stress revealed significant molecular changes due to3OC8-HSL.A total of 560 genes were differentially expressed in the 3OC8-HSL-treated vs.untreat-ed salt-stressed roots,with 177 genes upregulated and 383 downregulated(adjusted P＜0.05).The GO enrichment analysis of these DEGs indicated that 3OC8-HSL activated multiple stress-responsive path-ways.Many of the upregulated genes were associated with secondary metabolite biosynthesis and de-fense-related processes.In particular,biological process categories such as phenylpropanoid biosynthet-ic and metabolic pathways(involved in the synthesis of lignin and other phenolics),glutathione metabo-lism,response to wounding,and cuticle development were significantly enriched among the 3OC8-HSL-induced genes.These results implied that 3OC8-HSL would trigger a broad reprogramming of the plant's stress response at the molecular level,enhancing both structural and chemical defenses under the salt stress.Importantly,several key salt-tolerance genes were strongly upregulated by 3OC8-HSL treatment.For instance,transcripts of the MdPAL(phenylalanine ammonia-lyase,a rate-limiting enzyme in the phenylpropanoid pathway leading to lignin synthesis)increased 4.6-fold in the 3OC8-HSL-treat-ed roots(after 7 days of salt stress)compared with the untreated controls.The MdHKT1,encoding a high-affinity K+transporter involved in Na+/K+homeostasis,was upregulated 9.6-fold,and the MdLRR-RLK,encoding a leucine-rich repeat receptor-like kinase implicated in stress signal perception,rose by 8.4-fold(both after 7 days).Additionally,the MdGST(glutathione S-transferase,involved in detoxifica-tion and ROS scavenging via the glutathione pathway)showed a 6.4-fold induction at 24 hours after treatment.The robust induction of these genes,which would play roles in lignin biosynthesis(cell wall fortification),antioxidant activity,ionic transport,and stress signaling,would underscore the multi-fac-eted mechanism by which 3OC8-HSL would enhance salt tolerance.[Conclusion]This study demon-strated that the exogenous 3OC8-HSL improved the salt tolerance of Malus robusta seedlings by pro-moting growth,enhancing photosynthetic capacity,maintaining Na+/K+homeostasis,and reducing oxi-dative damage.The transcriptome and RT-qPCR analysis showed that the 3OC8-HSL upregulated the expression of the MdPAL,MdGST,MdHKT1,and MdLRR-RLK,and activated pathways related to phen-ylpropanoid metabolism and glutathione metabolism under the salt stress.These results would provide a theoretical basis for the application of AHL signals in improving salt resistance of apple rootstocks.

Abstract:Persea americana Mill.is an important tropical and subtropical economic crop with high nu-tritional value,widely and globally cultivated.At present,avocado cultivation in China is mainly con-centrated in Guangdong,Guangxi,Yunnan and other provinces,but the main cultivars are single(most-ly Hass),and the cultivation performance varies in different producing areas.The development of the avocado industry is in urgent need of excellent cultivars suitable for local conditions.Thus,domestic scientific research institutions have strengthened avocado breeding,and a number of local-adapted culti-vars have been selected.Tenglong,a new avocado cultivar with high yield,stable production and good quality,was bred by Guangxi South Subtropical Agricultural Science Research Institute,which per-formed excellently in regional trials of avocado producing areas in Guangxi.As early as 1956,Guangxi South Subtropical Agricultural Science Research Institute introduced a batch of Guatemalan race avoca-do seedlings for trial planting in its research base.After years of observation on the propagation and cul-tivation of these seedlings through multiple generations,the Tenglong strain was initially screened from the offspring of multi-generational propagated seedlings in 1986.In 2016,the grafted seedlings of Teng-long were planted in the avocado orchard of the institute with a spacing of 5 m×6 m(22 plants per mu),using 5-plant plots with 5 replicates.Through 3 generations of continuous observation on the growth and fruiting habits of the grafted seedlings,Tenglong showed stable economic traits,high-yield perfor-mance and good fruit quality.Its genetic independence was confirmed by Simple Sequence Repeat(SSR)molecular marker analysis.In 2019,yield measurement was conducted,and the single-plant yield ranged from 22 kg to 38 kg.In 2020,field identification was carried out,with an average single-plant yield of 22.8 kg.In February 2022,an application for new plant variety rights was filed with the name Tenglong.In December 2024,it passed the certification of improved forest tree varieties by the Forest and Grass Variety Certification Committee of Guangxi Zhuang Autonomous Region,with the certifica-tion number Guir-SC-PA-022-2024.Tenglong is a mid-maturing avocado cultivar for fresh consump-tion.It has vigorous tree vigor,a tall tree shape and luxuriant branches and leaves.The leaves are ellipti-cal,with a length to width ratio of 2.5 and a shape factor of 0.5280.It has type A flowers,and the flower-ing period is in early March.The fruit development period is 162-172 days,which ensures sufficient nu-trient accumulation.The fruits ripen in early September;when ripe,the fruit stalks become yellow and the peel is smooth and green.Grafted seedlings can bloom and bear fruit in the 3rd year after planting,and enter the full fruiting period in the 4th-5th year,with a yield of about 501.6 kg per 666.7 m2 during the full fruiting period.The fruits of Tenglong are elliptical,with a fruit shape index of 1.44.The average single fruit weight at maturity is 511.9 g,the peel thickness is 0.81 mm,and the edible rate is 78.6％.The soluble solid content is 5.6％,the dry matter content is 19.39％,the protein content is 0.84 g·100 g-1,the vitamin C content is 9.23 mg·100 g-1,the total sugar content is 1.54 g·100 g-1,and the fat content is 14.6 g·100 g-1.The peel of fresh fruits is medium olive green and smooth,while that of ripe fruits turns yellowish-green.The flesh is delicate and soft.Compared with the control cultivar Guikenda 2,Ten-glong has larger fruits,higher edible rate,significantly lower astringency(not obvious in avocado),bet-ter taste,more stable yield and better commercial quality.Tenglong has strong adaptability and is easy to cultivate and manage.It is suitable for cultivation in areas with an annual average temperature of 21-23℃,a minimum temperature of≥13.5℃in the coldest month,an extreme low temperature of≥0℃,an annual rainfall of 1000-2000 mm and little typhoon impact.The suitable soil is sandy loam with a depth of more than 1.0 m,a groundwater level below 1.5 m and a pH value of 4.5-6.0.Due to its excel-lent economic traits,early fruiting,as well as high and stable yield,Tenglong is suitable for promotion and cultivation in Chongzuo area of Guangxi and other ecological areas with similar conditions.

Abstract:Xinshiyu is an early-mid ripening pear cultivar(Pyrus bretschneideri×pyrifolia'Xinshiyu')bred from a cross between Yuluxiang and Shinseiki.The crossing was made in 2012.1371 hybrid seed-lings were raised in 2013.It was initially selected in 2016 for its bright colors and early ripening time.The regional adaptation test and cultivar compasion trial were conducted at multiple locations in Hebei Province,including Weixian(Xingtai),Yixian(Baoding),and Yutian(Tangshan),following top-grafting propagation.It was finally selected in 2023.The tree exhibited moderate growth,an open tree gesture,and moderate branching ability.Young branches were glabrous yellowish-brown in color.The leaves were orbiculate.The leaf shape index was 1.28.The leaf apex was long-caudate,the leaf base was round,the leaf margin was sharply serrated with awned teeth,non-lobed.The flower was white,with petals orbicular.The fruit is mainly round or oval in shape,and had a green-yellow ground color and a light red overcolor.The flesh was white,crispy,and juicy,with a balanced sweet-sour flavor and a pleas-ant aroma.The average fruit weight was 250.67 g,the maximum fruit weight was 257.82 g.The fruit shape index was 0.99.The content of soluble solid was 14.10%,the soluble sugar content was 10.60%,the content of soluble acid was 0.15%,the sugar-acid ratio was 70.67,the hardness was 4.77 kg·cm-2,and the content of Vitamin C was 33.00 mg·kg-1.The quality was excellent.The fruit development peri-od was 125 d and the fruit matured in early August in the southern-central region of Hebei Province;It exhibits high phenotypic plasticity to diverse soil and environmental conditions.The field trials con-firmed the absence of scab(Venturia nashicola),anthracnose leaf blight(Glomerella cingulata),and gray spot(Stemphylium vesicarium)under ordinary orchard management.The fruit had a long storage-life,the cold storage(-1-0℃)life was 7 months.The suitable cultivation areas should be major pear-producing areas in China.The variety had high yield potential.The suitable pollinizers should be Huangguan,Xueqing,Qiuyue and Yali.The Spacing would be(1.00-2.00)m×(4.00-4.50)m.The sim-plified light pruning protocol would be recommended.During blossom thinning,the outer florets and pendent-positioned flowers should be kept to ensure fruit shape uniformity.

Abstract:[Objective]As a perennial deciduous fruit tree species,plumcot(Prunus domestica×arme-niaca)exhibits significant physiological fruit drop during the maturation period,which substantially re-duces marketable fruit yield.During harvesting operations,the lack of mechanized harvesting equip-ment and standardized operational procedures leads to prevalent mechanical damage to fruits,including surface abrasions and flesh bruising.Furthermore,infestations by various fruit tree pests and diseases further exacerbate both yield losses and quality deterioration.Postharvest physiological activities,in-cluding accelerated respiration and ongoing ripening processes,coupled with improper bulk storage practices,lead to significant fruit decay,quality deterioration,and substantial postharvest losses.Opti-mal low-temperature storage conditions can effectively delay fruit senescence and decay,activate the an-tioxidant defense system,and extend storage duration.Monitoring physiological indices associated with fruit quality provides comprehensive insights into the physiological responses to ambient temperature fluctuations during storage.This study investigated six plumcot cultivars including Weidi,Fengweimei-gui,Weiwang,Fengweihuanghou,Konglongdan and Weihou to evaluate their physiological and pheno-typic changes under low-temperature storage for identifying the most storage-tolerant varieties.[Meth-ods]The storage experiment was conducted at the Jiamu Experimental Station in Wensu County,Aksu Prefecture,Xinjiang,starting in June 2024,using fruits from the plumcot germplasm resource nursery as test materials.Fruit maturity was determined by measuring firmness,soluble solids content(SSC),and color index using a GY-4 fruit firmness tester and an NK-55T handheld digital refractometer.Matu-rity standards were established based on the typical characteristic reference ranges for each cultivar at commercial maturity under optimal cultivation conditions,reflecting their general ripening perfor-mance.The harvest index ranges were determined through comprehensive analysis of our research group's preliminary results,multi-year observational data,and industry standards.Fruits were stored at(4±1)℃for 45 days with four sampling time points(0,15,30,and 45 days).Quality parameters were measured at each interval,their correlations were analyzed,and a comprehensive evaluation model was constructed using principal component analysis.Fruit samples from six plumcot cultivars were collect-ed between June and November 2024.[Results]At the onset of storage,the single fruit mass of six plumcot cultivars followed this order:Weidi＞Weihou＞Fengweihuanghou＞Konglongdan＞Fengwei-meigui＞Weiwang.After 45 days of storage,the firmness reduction rates were:Konglongdan(80%),Fengweimeigui(75%),Weidi(68%),Fengweihuanghou(64%),Weihou(50%),and Weiwang(47%).The total acid(TA)content decreased by Weiwang(66.10%),Weihou(63.04%),Fengweihuanghou(51.92%),Weidi(51.72%),Fengweimeigui(38.16%),and Konglongdan(35.21%).The total sugar(TS)dynamics showed Weidi,Weihou,Fengweimeigui,and Fengweihuanghou peaked at storage end(12.82%,11.94%,9.66%,and 8.98%,respectively),increasing by 17.12%,21.90%,36.94%,and 1.17%from initial values.Konglongdan and Weiwang peaked at day 30(9.49%and 9.05%,respectively),with 1.88%and 29.84%increases.Throughout storage,water content and soluble solid content(SSC)showed minor fluctuations.Four cultivars of Fengweimeigui,Weiwang,Fengweihuanghou,and Kon-glongdan maintained above 85%water content,while Weidi and Weihou ranged from 76.81%to 81.72%.Weidi and Weihou consistently exhibited higher SSC levels.Initial water contents of six plum-cot varieties followed:Weiwang＞Konglongdan＞Fengweihuanghou＞Fengweimeigui＞Weidi＞Wei-hou.Decay susceptibility ranked below:Weidi＞Konglongdan＞Fengweimeigui＞Weiwang＞Fengwei-huanghou＞Weihou.Final decay rates reached:Konglongdan(100%),Weidi(53.3%),Fengweimeigui(40%),Weiwang(23%),Fengweihuanghou(13.33%),and Weihou(0%).Low-temperature storage sig-nificantly enhanced both antioxidant enzyme activities and fruit quality.Correlation analysis revealed varying degrees of interindicator relationships with information overlap.Principal component analysis demonstrated Weihou exhibited optimal storage quality and tolerance,followed by Fengweihuanghou and Weidi,and then Weiwang and Konglongdan,with Fengweimeigui showing poorest performance.[Conclusion]Physiological indices and storage related phenotypic changes of six plumcot varieties were measured during low temperature storage.The(4±1)℃storage condition effectively reduced fruit decay,slowed softening rate,balanced internal moisture content,and activated reactive oxygen species scavenging systems,thereby extending storage duration and improving fruit quality.Results demonstrat-ed that Weihou exhibited superior storage quality under(4±1)℃conditions compared to the other five cultivars,ranking as the most storage tolerant variety,followed by Fengweihuanghou and Weidi,and then Weiwang and Konglongdan,with Fengweimeigui showing the poorest performance.These find-ings provide theoretical support for postharvest quality maintenance and storage period extension in plumcot fruits.Results indicated that storage at(4±1)℃effectively preserved the quality of plumcot fruits.Among the tested cultivars,Weihou exhibited the optimal storage performance due to its superior comprehensive characteristics and more efficient antioxidant system,outperforming the other five vari-eties.The storage quality ranking was as follows:Weihou＞Fengweihuanghou＞Weidi＞Weiwang＞Konglongdan＞Fengweimeigui.These findings provide critical scientific basis for cultivar selection and postharvest management in the plumcot industry,with significant practical implications for extend-ing shelf life and enhancing commercial value.

Abstract:Yunxiang 1 is a new small-fruit-type purple kernel walnut variety selected from seedling re-sources of Juglans sigillata in Ludian County,Yunnan Province.The nut is spherical and uniform,and the shape is beautiful;the average diameter of the nuts is 2.84 cm.The shell features shallow grooves,the shell thickness is 0.87 mm,and the nut weight is 7.32 g.The kernel weighs 4.93 g,exhibits a light purple color,and is plump with an intact extraction rate.The kernel rate is 67.35%.The kernel has a del-icate texture and rich aroma without astringency.The walnut kernel has an oil content of 65.1%,and a protein content of 18.5%.The tree vigor is strong,the tree posture is semi-open,and it is naturally open.The 1-year-old dormant branches are purple-brown,with prominent lenticels and sparse density.Mixed bud is triangle with no stalk.There are 9-13 small leaves,and the top leaves are mostly degenerated and spindle-lanceolate.It germinates in early March in Ludian,the male flower disperses in late March,the female flower blooms in early and middle April,the female flower stigma is light red,the flowering habit is protandry,the fruit matures in mid-September,and the leaves fall in late November.The green fruit(husk)is spherical,the fruit surface is covered with yellow fluff,the fruit point is obvious,and the fruit top is not prominent.The clone of this variety blossoms and bears fruit in the second year after the top-working of 4-5 years old tree(3-4 years earlier than that of Yangbi Pao walnut),which has obvious early-fruiting trait.The fruiting branches of the mother tree account for 50.3%,and the fruit branch rate is 70.2%.There are three or four more fruits,with an average of 2.6 fruits per fruiting branch.The aver-age crown projection area produces 0.36 kg·m-2 of dried nut.This variety has the characteristics of early fruiting,high yield,round nut shape,uniform and beautiful,full and plump kernel,easiness to take out the whole kernel,light purple kernel,high kernel rate,excellent taste and so on.At the same time,it has good cold,disease and insect resistance.It is a rare new variety of small-fruit-type walnut,which can be applied to the development and utilization of walnut food for kernel,tourism and leisure snacks.It has significant potential in improving quality and efficiency and optimizing variety structure in walnut planting base in Yunnan.The popularization and application of this variety is expected to effectively im-prove the yield and quality of walnut fruit,enhance market competitiveness,and improve the compre-hensive benefits of the industry.It is suitable for Ludian County at an altitude of 1600-2100 m,with an average annual temperature of 12-16℃and an annual rainfall of 800-1100 mm,≥10℃active accumu-lated temperature≥3500℃area and the surrounding similar conditions of planting.

Abstract:[Objective]Ziziphus jujuba Mill.'Lingwuchangzao'belongs to Rhamnaceae Jujube.Its fruits are rich in protein,sugar and other nutrients,and have high economic value and market develop-ment potential.It uasually propagated by root tillers and grafting.The study aimed to reveal the differ-ences of soluble sugar metabolism in the fruits of Lingwuchangzao propagated by different propagaion methods through studying on the changes of soluble sugar content in different developmental stages of the fruits of Lingwuchangzao propagated by root tillers and grafting in order to provide a scientific ba-sis for improving fruit quality.[Methods]The investigation was carried ou at the white ripening stage(NB vs JB),coloring stage(NZ vs JZ),and mature stage(NC vs JC)on the fruits of Lingwuchangzao propagated by root suckers and grafting as experimental materials,.The contents of glucose,fructose,sucrose and soluble sugar in the fruits of the three periods were determined respectively.Combined with transcriptome data analysis,significant differential genes were screened from four key sugar me-tabolism pathways,glycolysis/gluconeogenesis(ko00010),starch and sucrose metabolism(ko00500),fructose and mannose metabolism(ko00051),and amino sugar and nucleotide sugar metabolism(ko000520)with FDR＜0.05 and|log2FC|≥1 as the standard.By integrating phenotypic data with tran-scriptome data for WGCNA analysis,key differential genes regulating soluble sugar synthesis and me-tabolism at different developmental stages of Lingwuchangzao fruits were identified,followed by qRT-PCR verification to ensure the reliability of the results.[Results]The soluble sugars in Lingwuchang-zao included sucrose,fructose,glucose and others.The fructose was the main sugar accumulated at white ripe stage and coloring stage,while sucrose was the main sugar at mature stage.However,sugar accumulation exhibited significant developmental stage specificity in the fruits of Lingwuchangzao propagated with different methods.At the white ripe stage,the soluble sugar content of the fruits from Lingwuchangzao propagated by grafting was 17.55%higher than that from root tillers.At the coloring stage and maturity stage,the soluble sugar content of fruits from the Lingwuchangzao propagated by root tillers was 24.38%and 27.91%higher than that from grafted trees,respectively.At the coloring and mature stages,the sucrose content in the fruits fruits from Lingwuchangzao propagated by propagated by root tiller was 50.63%and 49.32%higher than that from grafted trees,respectively.At the coloring stage,the fructose content of in the fruits fruits from root tiller propagated trees was 20.25%higher than that from grafted trees.At the mature stage,the fructose content in the fruits from grafted trees was 13.32%higher than that from root tiller propagated trees.As the fruit grew and developed,the glucose content in the fruits from grafting propagated trees was 36.08%,20.67%,and 26.85%higher than from the trees propagated by root tiller,respectively.24 significantly differentially expressed genes(DEGs)were screened.Among them,the genes EP3(ncbi_107406053),BAM1(ncbi_107422617),BGLU11(nc-bi_107426268),PGMP(ncbi_107414395)showed higher expression level,and the difference of the gene expressions between the coloring period and the maturity period was significant,indicating the po-tential for further fluorescence quantitative analysis.Through GO functional enrichment analysis,it was found that there were significant differences in carbohydrate metabolism,hydrolytic enzyme activity and secondary metabolite synthesis between the trees propagated by two different methods.These dif-ferences might be closely related to the adaptability of trees and the fruit quality.The analysis of soluble sugar metabolism pathways and differential genes revealed that the gene PGMP(ncbi_107414395)ap-peared multiple times in the metabolic pathways,indicating that this gene might play an important role in regulating soluble sugars in Lingwuchangzao and could serve as a key candidate gene for further vali-dation studies.Additionally,weighted gene co-expression network analysis(WGCNA)showed that the black,brown,and green modules were significantly associated with soluble sugar metabolism.Genes in the black module exhibited a strong positive correlation with fructose,with a correlation coefficient of 0.87;genes in the brown and green modules showed strong positive correlations with soluble sugar and sucrose,with correlation coefficients of 0.71,0.86,0.74,and 0.83,respectively.Finally,the genes ncbi_112492650 and HERC2(ncbi_107420452),which exhibited the highest connectivity and high expres-sion level in the black module,were selected as key candidate genes for subsequent validation.Through the fluorescence quantitative analysis(qRT-PCR),it was found that the trend of gene expression levels in the fruits from the trees grafted by root-tiller was basically consistent with the transcriptome sequenc-ing results at the white ripe stage,coloring stage and mature stage,indicating that the transcriptome data had high reliability.[Conclusion]This study revealed the difference of soluble sugar metabolism in the fruits of Lingwuchangzao propagated by two differnt methods,providing an important theoretical basis for optimizing the propagation mode of Lingwuchangzao.The genes ncbi_112492650,HERC2(ncbi_107420452)and PGMP(ncbi_107414395)would play a key role in regulating soluble sugar metabo-lism of Lingwuchangzao,and could be used as subsequent key verification genes.

Abstract:Manshanhong is a new high-quality loquat cultivar with medium maturing and yellow flesh,obtained from a cross between the female parent Ninghaibai and the male parent Jiefangzhong.Hybrid-ization was carried out in December 2011,hybrid fruits were harvested in late May 2012,and seeds were collected and germinated in nutrient pots.In spring 2013,450 hybrid seedlings were transplanted to the same base for field evaluation.The offspring of the hybrid began to blossom in 2016 and initiated fruiting in 2017.After 3 years of continuous analysis and evaluation,a superior genotype(temporarily numbered A207)was finally selected from the 450 hybrids,exhibiting delayed flowering,strong stress resistance,uniform fruit appearance,high fruit-setting rate,and superior fruit quality.From 2017 to 2019,three consecutive years of phenotypic evaluations confirmed the stability of its botanical and agro-nomic traits.It was provisionally named Zhehong 1,and in 2020,it was granted national plant variety rights under the official denomination Manshanhong.To validate its adaptability and commercial poten-tial,200 grafted seedlings were propagated in 2018 and introduced to demonstration orchards,including Yuhang District and Lanxi City,through a technology transfer agreement.These trial plantings began fruiting in 2022,with consistent trait performance observed over three consecutive years,confirming its stability across diverse environments.Manshanhong is a vigorous,semi-spherical,open-canopy tree with a distinct central leader.The trunk exhibits a grayish-white hue,sparse lenticels,and moderate pu-bescence.Mature one-year-old branches are brown,with an average length of 57.0 cm and a diameter of 1.4 cm for central branches,while lateral branches measure 44.5 cm in length and 1.3 cm in diame-ter.The tree produces five lateral branches per central branch on average,with medium branching ca-pacity.Leaves on one-year-old spring shoots are dark green,thick,and rigid,with an elliptic in shape(32.9 cm×12.1 cm,and length-to-width ratio 2.7).The leaf is slightly wrinkled,with a tapered apex,cuneate base,and flat margins.Leaf thickness averages 0.43 mm,with a concave cross-sectional pro-file.The adaxial surface is light green and pubescent,while the abaxial surface is gray-yellow with mod-erate pubescence and prominent reticulate venation.Leaf margins bear shallow,medium-density serra-tions covering half of the edge,with 16-18 pairs of lateral veins.Petioles are short(1.1 cm)and thick(5.5 mm),with deciduous stipules averaging 13.5 mm in length.Manshanhong flowers in late autumn to winter,with a delayed phenology:initial flowering occurs in early December,full bloom from late December to early January,and terminal flowering in late January to early February.Inflorescences are conical,averaging 9.5 cm in length and 10.5 cm in width,with eight horizontally spreading rachises per cluster.Each inflorescence bears approximately 106 flowers,characterized by yellow-white petals(26.6 mm in diameter),five pistils,and 22-24 stamens per flower.Fruits ripen around May 25 in Hai-ning City,Zhejiang province,and a near-spherical shape with closed calyx cavities.Post-thinning fruits average 48.9 g in weight.The peel is orange-yellow,resilient,and easy to separate from the flesh.The orange-yellow pulp has medium firmness,tender texture,high juiciness,and excellent melts in the mouth.Biochemical analysis reveals soluble solids content(SSC)of 14.9%,titratable acidity(TA)con-tent of 0.31%,and an edible rate of 75.8%.Each fruit contains 5.8 seeds on average.This variety exhib-its strong resistance to fruit cracking and sunscald,coupled with excellent fruit quality.Under open-field cultivation,the average yield reaches 979.9 kg per 666.7 m2 for six-year-old trees.Manshanhong represents a significant advancement in yellow-fleshed loquat breeding,combined with delayed phenol-ogy,robust adaptability,and superior fruit traits,marking it apromising leading cultivar for commercial loquat production.

Abstract:[Objective]Walnut(Juglans regia L.)is a crucial tree species with both ecological and eco-nomic importance.In China,it plays a significant role in agricultural development,particularly in the southern region of Xinjiang,where walnut cultivation constitutes a major source of income for local farmers.As of 2024,the total walnut cultivation area in Xinjiang reached 6.4 million mu,with an output of approximately 1.445 million tons,accounting for about 22%of the national production.The total out-put value exceeded 17 billion CNY,demonstrating a significant year-on-year increase.However,the ar-id climatic conditions,sandy soil texture,and high evaporation rates in the region pose challenges to sustainable walnut production.Traditional surface irrigation methods often result in low water use effi-ciency and accelerate nutrient leaching,further exacerbating resource waste and limiting yield potential.To address these challenges,this study investigated the effects of different irrigation and fertilization levels under micro-sprinkler fertigation conditions on walnut yield,nut quality,and resource use effi-ciency.The aim was to determine the optimal water and fertilizer input strategy during the walnut grow-ing season to enhance yield and quality while improving water and nutrient use efficiency.This ap-proach is expected to provide a sustainable solution to water and nutrient management,ultimately achieving water-saving,fertilizer-saving,and yield-increasing goals in arid regions.[Methods]A field trial was conducted using the walnut cultivar Wen 185 as the experimental material.A split-plot design was adopted with two irrigation levels and three fertilization levels,resulting in six water-fertilizer cou-pling treatments in total.An additional treatment following local farmers'conventional management practices was included as a control(CK).The experimental setup aimed to explore the interactive ef-fects of irrigation and fertilization levels on walnut fruit quality,yield,water use efficiency(WUE),and partial factor productivity of fertilizer(PFP).Key parameters measured included fruit biochemical com-position(e.g.,fat content,cellulose,reducing sugars,total sugars,soluble protein,tannins,and total phe-nolics),yield per unit area,and efficiency indicators.To further identify the optimal combination of irri-gation and fertilization,a dual-variable second-order polynomial regression model was constructed for yield,WUE,and PFP.Multi-objective optimization was performed using the Non-dominated Sorting Genetic AlgorithmⅡ(NSGA-Ⅱ),which efficiently searched the solution space for the optimal fertiga-tion strategy.[Results]Walnut yield,WUE,and PFP exhibited a non-linear response to increasing wa-ter and fertilizer inputs,generally showing a trend of initial increase followed by decline.This indicated that excessive input may lead to diminishing returns or even adverse effects.Compared with irrigation,fertilization had a greater influence on yield and WUE,though a significant synergistic interaction be-tween water and fertilizer was observed.Under fixed irrigation conditions,both WUE and PFP in-creased with higher fertilization up to a certain point,beyond which they began to decline.A similar trend was observed when fertilization level was held constant and irrigation amount varied.The best performance in terms of yield,quality,and resource efficiency occurred under moderate irrigation and fertilization levels,demonstrating the importance of balanced inputs.Nut quality was significantly influ-enced by different water-fertilizer coupling treatments.Specific combinations of irrigation and fertiliza-tion markedly enhanced the accumulation of bioactive compounds(e.g.,total phenolics),cell wall com-ponents(e.g.,cellulose),sugars,and fats in walnut kernels.Both excessive(high water and high fertiliz-er)and deficient(low water and low fertilizer)treatments suppressed walnut growth and development.In contrast,an appropriate water-fertilizer combination significantly promoted nut quality and yield.Compared to the low water-low fertilizer treatment,the optimized fertigation strategy increased irriga-tion by approximately 91-98 m3·666.7 m-2 and fertilization by 52-63 kg·666.7 m-2.This resulted in in-creases in reducing sugar(by 0.27%),total sugar(by 0.02%),yield(by 135-136 kg·666.7 m-2),and WUE(by 0.04-0.08 kg·mm-1·666.7 m-2),while fat content,cellulose,soluble protein,tannins,total pheno-lics,and PFP decreased by 5.25%,0.34%,0.14 mg·g-1,0.55 mg·g-1,2.31 mg·g-1,and 3.65-6.71 kg·kg-1,respectively.When compared to the local farmers'conventional practice(CK),the optimized treatment increased fat content by 0.08%,reducing sugar content by 0.35%,yield by 145-149 kg·666.7 m-2,WUE by 0.29-0.34 kg·mm-1·666.7 m-2,and PFP by 14.86-17.91 kg·kg-1.Meanwhile,cellulose,soluble protein,tannins,total sugar,and total phenolics decreased by 0.48%,0.23 mg·g-1,1.52 mg·g-1,0.03%,and 1.09%,respectively.These results indicated that optimized fertigation can lead to substantial im-provements in both yield and resource use efficiency,with slight trade-offs in some quality traits.[Con-clusion]Irrigation and fertilization levels significantly influence walnut fruit quality and yield,with a clear synergistic effect observed.The relationships between yield,WUE,and PFP with water and fertil-izer input levels followed a parabolic trend,suggesting that moderate input levels are critical to maxi-mizing production efficiency.Based on NSGA-Ⅱoptimization results,the optimal fertigation strategy for walnut during the growing season was determined to be an irrigation volume of 498.12 m3·666.7 m-2 and a fertilization amount of 139.72 kg·666.7 m-2.Under this regime,fat content reached 59.08%,yield reached 410.73 kg·666.7 m-2,WUE was 0.75 kg·m-3,and PFP reached 44.44 kg·m-3.Furthermore,dy-namic monitoring of both internal and external walnut fruit quality indicators throughout the growing season demonstrated close agreement with the model-predicted optimal irrigation levels,confirming the accuracy and practical relevance of the optimized fertigation strategy.The high consistency between em-pirical monitoring and model-based simulations underscores the reliability of this approach and pro-vides a scientific basis for water and nutrient management in walnut production under arid conditions.These findings offer valuable guidance for promoting resource-efficient and sustainable walnut cultiva-tion in Xinjiang and similar agroecological regions.

Abstract:[Objective]Pear diseases pose a substantial threat to the pear industry in China.The use of traditional chemical pesticides has led to increasingly prominent environmental pollution and resistance problems.Therefore,there is an urgent need to develop environmentally friendly disease control meth-ods.In 2024,a newly emerged bark canker disease was observed on pear trees in Harbin City.Infected trees developed water-soaked and swollen lesions on the bark of 1-3-year-old branches,typically sur-rounded by a halo.As the disease progressed,multiple lesions formed on a single branch,eventually darkening,cracking open,and producing distinct black pycnidia.The bark desiccated,and in severe cas-es,branches fractured,severely impairing tree growth and productivity.This study aimed to identify the causal pathogen of this emerging disease and to screen for effective biocontrol bacterial strains,thereby providing a scientific basis for its prevention and management.[Methods]Symptomatic branches were surface-sterilized,and single-spore isolation was used to obtain pure fungal cultures.The pathogenicity of the isolate was tested using Koch's postulates on healthy pear twigs cultivated hydroponically,apply-ing non-wounded,wounded,and heat-injured inoculation methods.Pathogen identification was based on both morphological characteristics and multi-locus phylogenetic analysis using ITS,LSU,and Tef-1α gene sequences.Endophytic bacteria were isolated from healthy pear branches using tissue separation.Candidate biocontrol strains were screened through dual culture and co-culture assays with the patho-genic isolate.The most effective antagonistic strain was further characterized based on morphological,physiological,and biochemical properties,and identified using phylogenetic analysis of 16S rRNA and gyrB gene sequences.[Results](1)A fungal isolate designated LA-1 was obtained and found to re-produce field symptoms under wounded and heat-injured inoculations.These symptoms included wa-ter-soaked swelling and black pycnidia formation.The same fungus was re-isolated from symptomatic tissues and showed identical morphological and molecular characteristics to the original LA-1 isolate.ITS sequencing confirmed 100%identity withLA-1.(2)Morphological observations revealed that LA-1 formed immersed to semi-immersed,discoid,and dark brown to black pycnidia,measuring 650 to 950 μm in diameter(mean:740 μm,n=30).Pycnidia were multi-locular with shared walls,and indi-vidual locules measured 40 to 120 μm(mean:75 μm,n=30).Conidiophores were hyaline,clavate,occa-sionally swollen,and 0.75 to 2.25 μm wide(mean:1.5 μm,n=30).Conidia were unicellular and oval to cylindrical,containing oil droplets,and displayed a frontal central depression.They transitioned from hyaline to dark brown upon maturation and measured(15.5-)17.0 to 20.5(-22.5)μm×(6.0-)6.5 to 8.0(-8.5)μm,averaging 18.5 μm×7.0 μm(n=50).Colonies on PDA were initially white and floccose,later producing olive pigment and forming pycnidia after 13 days of incubation in the dark.These fea-tures were consistent with descriptions of Aplosporella ginkgonis.(3)Gene sequences obtained includ-ed 603 bp(ITS),1341 bp(LSU),and 170 bp(Tef-1α).BLAST analysis revealed that the ITS and Tef-1α sequences of the isolate exhibited＞99%similarity to those of A.ginkgonis and A.longipes in the NC-BI database.However,LSU comparisons were inconclusive due to length variation.To resolve species identity,maximum likelihood and Bayesian phylogenetic trees were constructed using the K80+R2+FO and K80+I models via IQ-TREE and MrBayes 3.2.6,respectively.Both analyses yielded identical topol-ogies,with LA-1 clustering with A.ginkgonis with full statistical support(BS/PP=100/1).Notably,sev-eral strains formerly designated as A.longipes were also nested within the A.ginkgonis clade.Based on morphological traits,multi-gene phylogeny,and ecological context,LA-1 was conclusively identified as A.ginkgonis.(4)Furthermore,eleven bacterial strains were isolated from healthy pear branches.Du-al culture and co-culture screening identified strain B10 as exhibiting the strongest antagonistic activity against LA-1.Colonies of B10 were milky white and opaque,with wrinkled surfaces and irregular edg-es on LB agar.Biochemical tests confirmed it was a Gram-positive bacterium.Phylogenetic analysis based on 16S rRNA and gyrB sequences identified B10 as Bacillus velezensis.Importantly,B10 pro-duced heat-stable antimicrobial metabolites;even after autoclaving at 121℃,its fermentation broth re-tained strong inhibitory effects on LA-1.Additionally,B10 suppressed the growth of other wood-infecting fungi,including Cytospora,Phaeobotryon,Diaporthe,and Phomopsis species.[Conclusion]A.ginkgo-nis was identified as the causal agent of a newly emerged bark canker disease on pear trees in Harbin,marking the first report of this pathogen affecting pear in China.Moreover,the identification of Bacil-lus velezensis B10 as an effective biocontrol agent offers a promising alternative to chemical fungicides.Its broad-spectrum activity and thermal stability highlight its potential for integrated management of wood-infecting pathogens in pear orchards.

Abstract:[Objective]Poor fruit set rate,unstable yield,and variable quality are the significant chal-lenges in cultivating the green peel and red flesh pomelo[Citrus maxima(Burm.)Merr.].This study ex-amined the effects of pollen source on fruit set,growth,and quality,with regard to xenia(pollen direct effect on fruit and seed traits)and metaxenia(its influence on maternal tissue development)The aim was to identify optimal pollinizer varieties to enhance yield and fruit quality.[Methods]Mature 10-year-old red-flesh,green-peel pomelo trees served as seed parents.Artificial cross-pollination was per-formed using pollen from three pomelo varieties:Hongbaoshi,Dongshizao,and Vietnam Red Pumme-lo.Fruit set rate,fruit growth,and quality parameters(single fruit mass,longitudinal diameter,trans-verse diameter,peel thickness,total soluble solids(TSS),titratable acid(TA),vitamin C(Vc)content,seed number,edible rate,flesh segment number,and flesh color)were measured.Self-pollination served as the control.Data analysis included correlation analysis and comprehensive analysis and evaluation of the impact of pollinizers on the fruit set rate,growth and development,and quality of the green peel red flesh pomelo.[Results]Cross-pollination significantly increased fruit set rate compared with self-polli-nation.Metaxenia effects were evident,resulting in a more uniform,nearly spherical fruit shape(fruit shape index closer to 1).Cross-pollinated fruits exhibited significantly higher levels of gibberellin(GA3)and cytokinin(CTK)compared to self-pollinated fruits.Auxin(IAA)significantly increased in fruits pollinated with Hongbaoshi Pomelo and Vietnamese Red Pomelo.TSS was 1%-2%higher than self-pollination,with Hongbaoshi achieving the highest(10.97%).Flesh redness,potentially linked to higher sugar accumulation,was enhanced.Vc content was also increased(40-50 mg·100 g-1 vs 30-40 mg·100 g-1 in self-pollinated fruit).Peel thickness was reduced but seed number increased(95-112vs average 71 in natural pollination).Hybrid seeds were cuneiform,flattened,with fin-like ribbed surfaces.While fruits from pollination with Vietnamese red pomelo had the thinnest peel and smaller fruit size.Correlation analysis revealed that fruit weight had a highly significant positive correlation with both fruit length and width(P＜0.01);fruit length exhibited a highly significant positive correlation with both fruit width and shape index(P＜0.01).Flesh recovery had a highly significant negative correlation with peel thickness(P＜0.01)and a significant positive correlation with seed number(P＜0.05).TSS exhibited a significant positive correlation while titratable acid content demonstrated a highly signifi-cant negative correlation with the solids-to-acid ratio(P＜0.05).Metaxenia and xenia effects varied sig-nificantly among pollinizer varieties.Based on comprehensive evaluation,the Hongbaoshi Pomelo as pollen source yielded the best fruit quality.[Conclusion]Cross-pollination significantly improved fruit set rate and enhanced multiple fruit quality attributes in red-flesh,green-peel pomelo,displaying pro-nounced Xenia and metaxenia effects.Hongbaoshi pomelo was identified as the most effective polliniz-er variety.Rational selection of pollinizer varieties in production is recommended to boost fruit set,yield stability,and fruit quality.This study provided practical guidance for improving the cultivation of red-flesh,green-peel pomelo.

Abstract:[Objective]Girdling is an important measure to preserve flowers and fruits and improve fruit quality in the cultivation process,but it's time-consuming and laborious.Most of the studies on girdling used a single variety of materials,and there was a lack of research on the fruit quality and fruit cracking of different varieties.Eight different jujube varieties were used as test materials to explore the effects of girdling on tree growth and development,yield per plant,fruit quality and fruit cracking of different jujube varieties,so as to provide theoretical basis for improving fruit quality,clarifying the pat-tern of tree growth and development after girdling,and reducing fruit cracking rate.[Methods]Eight fresh jujube varieties,including Zaohongmi,Yingqiuhong,Panzao,Liuyuexian,Lindong 2,Longpan-dongzao,Beijingsuanzao and Lengbaiyu,were taken as test materials,which were cultivated in a cold shed in Taigu District of Shanxi Province.The selected materials were healthy without pests and diseas-es and grew in a consistent manner.Girdling was carried out at the full-bloom stage of each variety.The tree growth,fruit soluble solids,titratable acid,yield per plant,fruit cracking rate and fruit shrinkage rate of the stripped and unstripped varieties were measured and compared.At the full-bloom stage,a secondary branch was left at the base of the trunk for girdling,and the girdling width was 1/6 of the trunk thickness.Each plant of each variety was repeated five times.The phloem was stripped to the xy-lem without damaging the xylem,and no girdling was set as the control group(CK).The fruit cracking rate is the number of cracking fruits per plant divided by the total number of fruits per plant,and the fruit shrinkage rate determination method is the same as the fruit cracking rate determination method.The measurement method of tree growth is to measure the growth and development index of the tree be-fore the girdling,and to measure it again after the tree stopped growing.As for other fruit quality and traits,refer to the'jujube germplasm resources description specifications and data standards'.[Re-sults]Girdling significantly increased the single fruit weight of each variety.Among them,the increase efficacy of single fruit weight of different varieties was as follows:Lindong 2＞Beijingsuanzao＞Liuyuexian＞Panzao＞Lengbaiyu＞Longpandongzao＞Yingqiuhong＞Zaohongmi,namely 10.66 g＞8.14 g＞6.39 g＞4.55 g＞3.6 g＞3.18 g＞2.16 g＞1.46 g.The longitudinal diameter of the fruit of Zao-hongmi,Panzao,Lindong 2 and Lengbaiyu was significantly different from that of the fruit without gir-dling,and the longitudinal diameter of the fruit after girdling was larger than that of the fruit without gir-dling.The fruit transverse diameter showed that the fruit transverse diameter of flat jujube,Liuyuexian,Lindong 2,Beijingsuanzao and Lengbaiyu after girdling was larger than that of the fruit without gir-dling and the difference was significant.The fruit lateral diameter of Zaohongmi,Yingqiuhong,Panzao,Lindong 2,Beijingsuanzao and Lengbaiyu had significant difference before and after girdling.The fruit lateral diameter of Lindong 2 and Beijingsuanzao increased the most.Girdling increased the soluble sol-ids content of fruits of all varieties except Lindong 2,and the increase effect of soluble solids content was 0.90%-5.65%.It had different effects on the change of titratable acid contents of different varieties.The titratable acid contents of Yingqiuhong,Longpandongzao,Beijingsuanzao and Lengbaiyu increased by 0.19%,0.12%,0.33%and 0.44%,respectively,after girdling,while the titratable acid contents of Zaohongmi,Panzao,Liuyuexian and Lindong 2 decreased by 0.07%,0.02%,0.21%and 0.36%,respec-tively.The fruit cracking rate of Zaohongmi was reduced by 15.02%,and the fruit shrinkage rates of Yingqiuhong,Lindong 2 and Longpandongzao were reduced by 26.19%,13.15%and 9.94%,respective-ly,while the fruit shrinkage rates of Panzao,Liuyuexian and Lengbaiyuwere increased by 2.22%,6.25%and 22.65%,respectively,compared with the control.Except for Lindong 2 and Longpandong-zao,the inhibition effect of tree height growth of each variety was as follows:Lengbaiyu>Liuyuexian＞Yingqiuhong＞Panzao＞Beijingsuanzao＞Zaohongmi,that is,9.3 cm＞6.9 cm＞6.2 cm＞3.1 cm＞0.6 cm＞0.5 cm.Girdling could significantly increase the yield per plant of each variety by 384.42 g-4 166.9 g.The effect of increasing yield was:Lengbaiyu＞Liuyuexian＞Beijingsuanzao＞Longpan-dongzao＞Lindong 2＞Panzao＞Yingqiuhong＞Zaohongmi,that is,4166.9 g＞3835.4 g＞3518.6 g＞2 401.1 g＞2 029.8 g＞1 693.7 g＞1 422.69 g＞384.42 g.The effects on the growth of stem diameter,crown width,secondary branch length and secondary branch diameter of different varieties were differ-ent.There was a significant positive correlation between single fruit weight and fruit longitudinal diame-ter,and a significant positive correlation between single fruit weight and fruit transverse diameter.The growth of secondary branch diameter was significantly and negatively correlated with soluble solids.The suitability degree of girdling for each variety was as follows:Lindong 2＞Lengbaiyu＞Panzao＞Liuyuexian＞Beijingsuanzao＞Longpandongzao＞Zaohongmi＞Yingqiuhong.[Conclusion]Girdling helps to improve the yield per plant and single fruit weight of each variety,increase the soluble solids content of each variety except Lindong 2,and effectively inhibit the tree height growth of each variety,but has different effects on the cracking rate and shriveling rate of different varieties.And there are dif-ferences in the growth of stem diameter,crown width,secondary branch length and secondary branch di-ameter of different varieties.Lindong 2,Lengbaiyu,Panzao and Liuyuexian are more suitable for gir-dling,while Zaohongmi and Yingqiuhong are suitable for labor-saving cultivation varieties.No(less)girdling is the main measure of labor-saving cultivation,and the varieties with easy fruit setting can be reduced or exempted from girdling.The varieties that must be stripped should be stripped as reasonably as possible,which is labor-saving and effective.

Abstract:[Objective]This study aims to explore the testing conditions and methods suitable for the texture characteristics of litchi fruit through whole fruit puncture test and Texture Profile Analysis(TPA).Puncture test refers to the use of a millimeter diameter probe to puncture a sample,which can de-termine the hardness and brittleness of the sample,and it is also commonly used for peel analysis.TPA testing simulates the chewing motion of the human oral cavity and compresses the sample twice.This process can determine the texture parameters such as hardness,adhesion,elasticity,cohesion,and chew-iness of the sample.Meanwhile,through variance analysis,correlation analysis,principal component analysis,and cluster analysis of the texture parameters of different lychee varieties,a preliminary quanti-tative evaluation method for lychee fruit quality was established.[Methods]This study used mature Shuidong fruits as experimental materials.Firstly,physiological indicator data of fresh fruits were col-lected,including fruit weight,fruit volume,fruit size,etc.Then,using puncture and TPA methods,refer-ring to relevant literature,single factor tests were conducted on indicators such as deformation,testing speed,puncture depth,and trigger force.To clarify the optimal conditions for determining the texture of lychee fruit,we set multiple gradients for each detection factor in this experiment.Prior to the start of the formal experiment,pre-experiments were conducted on the test samples and basic testing condi-tions.And three fruit texture analysis and testing modes have been established:whole fruit puncture method,whole fruit TPA method,and whole fruit peeling TPA method.During testing,the suture line of the fruit is parallel to the storage platform,with the highest point on the sunny side as the testing point.Five fruits were measured for each treatment.In addition,this study used 8 lychee cultivars including Shuidong,Feizixiao,Chiye,Renshanli,Zaomi,Heiye,Leiling Xiaolingxiang,and Ziniangxi as experi-mental materials to analyze and evaluate the texture of lychees and test the adaptability of the optimal conditions.[Results](1)The results of the single factor experiment showed that the optimal parameters for detecting lychee fruit peel by puncture method were puncture depth of 4 mm,testing speed of 0.5 mm·s-1,and triggering force of 0.38 N;The optimal testing level for TPA testing of lychee whole fruit(with and without skin)is a deformation of 20%,a testing rate of 0.5 mm·s-1,and a triggering force of 0.38 N.(2)The analysis of fruit texture parameters of different lychee varieties showed that there were differences in texture indicators between each variety in the puncture test and TPA test.Among them,in the puncture test,the variation amplitude of peel strength was the smallest,with a coefficient of varia-tion of 14.35%.The peel strength of Feizixiao was the highest,significantly higher than the other seven varieties;In the TPA whole fruit with skin analysis,the recovery of Feizixiao was significantly higher than that of other varieties except for Chiye;In the whole fruit peeling TPA experiment,the chewiness of the flesh of Renshanli and Zaomi was significantly higher than that of other varieties(P＜0.05),while there was no significant difference in the chewiness of the flesh of Heiye,Shuidong,Leiling Li-lac,and Ziniangxi.(3)The correlation analysis of texture indicators of different lychee varieties showed that the skin hardness was very significantly and positively correlated with the maximum displacement of the peel and the penetration of the fruit peel(P＜0.01),the hardness of the fruit flesh was highly sig-nificantly and positively correlated with chewiness(P＜0.01),and highly significantly and negatively correlated with cohesiveness and resilience(P＜0.01).Elasticity and chewiness were highly significant-ly and positively correlated(P＜0.01).These results indicated that important indicators in the puncture test included peel hardness,peel maximum displacement,and puncture work,while important indica-tors in the TPA test included fruit hardness,cohesiveness,resilience,chewiness,and elasticity.(4)Using principal component analysis,6 factors were extracted from 28 indicators(phenotype indicators and tex-ture analyzer parameter indicators),with a cumulative variance contribution rate of 87.90%,represent-ing the vast majority of texture characteristics,which can basically analyze the main reasons for the di-versity between different lychee germplasm resources.The first and second principal components can be used as important indicators for variety identification.Fifteen indicators with load values greater than 0.8 were extracted for cluster analysis,and the texture indicators were divided into three catego-ries.Eight lychee cultivars were also divided into three categories,indicating that the selected important indicators can be used to distinguish the texture characteristics of different lychee fruits.[Conclusion]Compared with TPA test,whole fruit puncture test is more suitable for analyzing the texture of fruit skin.In TPA,the compression of whole fruit with skin can also reflect the texture characteristics of fruit flesh to a certain extent.This study preliminarily determined the standardized parameters for lychee puncture test and TPA test and screened out the core indicator group that can be used to evaluate the tex-ture characteristics of lychee fruit.The combination of puncture method and TPA method can effective-ly distinguish the texture differences between different germplasm resources,enriching the content of ly-chee texture evaluation.