Abstract:Composting treatment is one of the crucial approaches to achieve the harmlessness and resource utilization of agricultural wastes.Nevertheless,conventional composting methods suffer from issues such as a prolonged fermentation period,low conversion efficiency,significant nutrient loss,difficult control of secondary pollution,as well as the emission of odors and greenhouse gases.Microorganisms have emerged as effective means to address the aforementioned problems due to their characteristics of promoting decomposition,deodorization,emission reduction,and enhancing fertilizer efficacy.Regarding the bioaugmentation technology for composting using agricultural wastes as raw materials,this paper summarizes the application and research progress of bioaugmentation technology in the composting process of agricultural wastes at home and abroad from aspects such as the types of functional microbial strains and screening,the construction of complex microbial agents,the functions of microorganisms,and the influencing factors and mechanisms of bioaugmentation.Moreover,it explores the existing problems in the composting process of agricultural wastes and proposes the development trends and countermeasure suggestions for the resource treatment and utilization of agricultural wastes.

Abstract:The winter wheat double-width and double-pressure strip seeder developed by College of Mechanical&Electrical Engineering of Henan Agricultural University was introduced,and three sowing methods,namely conventional equal row space mechanical strip seeding(CS),wide-width mechanical strip seeding(WS)and double-width and double-pressure strip seeding(DDS),were set up to study the effects of different sowing methods on population photosynthetic characteristics,nitrogen accumulation and transport and yield of winter wheat.The aim of this study was to define the suitable sowing method for wheat field with the clay tidal soil in southeastern Henan Province,and provide theoretical basis and technical support for the improvement of winter wheat sowing quality and the high yield and efficient production of agricultural machinery and agronomic integration in this area.The results showed that compared with CS treatment,WS and DDS treatments increased leaf area index,chlorophyll content,population photosynthetic rate after booting,nitrogen translocation amount before anthesis,nitrogen accumulation after anthesis,and significantly increased panicle number,grain number per spike and yield,especially DDS treatment,with an average increase of 6.94%and 12.68%in 2 years for WS and DDS treatments,respectively.In conclusion,WS and DDS treatments can effectively improve the population photosynthetic performance of winter wheat,promote nitrogen accumulation and transport,and achieve increase of yield.DDS treatment is the best,and can be used as a suitable sowing method for winter wheat in the moist soil region of southeast Henan Province.

Abstract:Bacillus subtilis can form spores,has strong resistance and good stability,and has several advantages compared with conventional probiotics.Bacillus subtilis can be used as a microecological agent in livestock,poultry and aquaculture production,and has positive impact on animal production performance via improvement of digestion and absorption.Bacillus subtilis can improve meat quality,enhance immunity and regulate intestinal health.The biological characteristics of Bacillus subtilis,the application in livestock,poultry and aquaculture production and the impact on intestinal health were reviewed in this paper,so as to provide reference for further development and utilization of Bacillus subtilis microecologics for feeding.

Abstract:In order to determine the controlling efficacy of Bacillus velezensis EA19 combined with chemical agents on Fusarium head blight(FHB),the optimal combination ratio was determined by the mycelium growth rate method,plate colony counting method and Horsfall method,and then verified by detached wheat spikes inoculation tests and field trials.The results showed that the inhibition rates of spray powder and freeze-dried powder of EA19 fermentation broth on the mycelial growth of Fusarium graminearum and F.asiaticum at different concentration were 22.53%—93.96%,and the EC50 values were in the range of 5.794 4-10.916 4 cfu/mL.The strain EA19 had good biocompatibility with 25-100 µg/mL carbendazim,but not with 25-100 µg/mL prochloraz and tebuconazole.When carbendazim was combined with spray powder or freeze-dried powder of EA19 at the volume ratio of 6∶4,7∶3 and 8∶2,the co-toxicity to F.graminearum and F.asiaticum was the highest,and the greatest toxicity ratio was 1.15-1.36 in these ratios.The control efficacy on FHB of detached wheat spikes by the combination of carbendazim and two types of EA19 powder with a concentration of EC50 in different volume ratios was 47.91%—73.50%.In field trials,when treated with the combination of EA19 freeze-dried powder with 30%reduced carbendazim,the control efficacy(53.76%),deoxynivalenol toxin content in wheat grains(0.50 mg/kg),and theoretical wheat yield(5 994.35 kg/ha)were not significantly different from those treated with full dosage of carbendazim.In conclusion,B.velezensis EA19 and carbendazim have synergistic effect in the control of FHB,and their combination can reduce the dosage of carbendazim.

Abstract:In order to screen high-efficiency composite bacteria that promote the degradation of cellulose and lignin in the composting process of mushroom residue,sodium carboxymethyl cellulose plate method,Congo red staining method and lignin plate method were used for preliminary screening,combined with filter paper strip disintegration test,aniline blue decolorization rate determination and cellulose and lignin enzyme activity determination test for rescreening from the mushroom residue waste,and then they were used for aerobic composting test to study the physical and chemical parameters and microbial community changes in the process,and to evaluate their degradation ability of cellulose and lignin in mushroom residue.The results showed that the enriched cellulose-degrading bacteria could completely degrade the filter paper within 6 days,and the activities of carboxymethyl cellulase(CMCase),filter paper enzyme(FPA),exoglucanase(C1)and β-glucosidase(β-Gase)reached 2.50,7.30,3.43 and 2.90 U/mL,respectively.The maximum decolorization rate of aniline blue reached 92.10%within 5 days by enriched lignin degrading bacteria,and the activities of lignin peroxidase(Lac),laccase(Lip)and manganese peroxidase(Mnp)reached 0.80,2.42 and 1.35 U/mL,respectively.The results of composting test showed that compared with the natural composting treatment(CK),the highest temperature of the pile body was 58.77℃,and the high temperature(>55℃)lasted for 5 days.The relative decomposition rate of cellulose and lignin increased by 35.83%and 54.33%respectively.The addition of microbial agents increased the richness of bacterial community in the middle stage of composting,and the relative abundance of Pseudomonas,Idiomarina,Glutamicibacter,Thiopseudomonas,Globicatella,Pusillimonas,Lysobacter and Brumimicrobium increased.Redundancy analysis(RDA)results showed that temperature,pH value and electrical conductivity(EC value)were the significant factors affecting the composition of bacterial community in the middle stage of composting.In summary,the composite degrading bacteria screened in this study can effectively degrade cellulose and lignin,and prolong the high temperature period of composting.

Abstract:In order to provide theoretical basis for pumpkin variety identification,germplasm conservation and innovation,31 pumpkin germplasm resources were used as materials,and 7 inter-simple sequence repeat(ISSR)primers with rich polymorphic information were selected to analyze the genetic diversity of the materials and establish DNA fingerprint map.The results showed that a total of 73 bands were amplified by 7 ISSR primers,including 72 polymorphic bands(polymorphic band rate:98.63% ).The average number of observed alleles,the average number of effective alleles,the average Nei's gene diversity index,and the average Shannon's diversity information index were 1.986 3,1.570 4,0.329 9 and 0.494 4,respectively.The interspecific genetic similarity coefficients ranged from 0.12 to 0.89,with an average value of 0.46.Unweighted pair-group method with arithmetic means(UPGMA)clustering analysis showed that 31 pumpkin materials were classified into Cucurbita moschata D.,Cucurbita pepo L.and Cucurbita maxima D.at the genetic similarity coefficient of 0.46.Furthermore,the DNA fingerprint map for 31 pumpkin materials was constructed using the 14 polymorphic sites amplified by primer UBC811 and primer UBC843.All varieties in the DNA fingerprint map were unique,which could be used for molecular identification of varieties.In conclusion,the genetic diversity of 31 pumpkin materials was rich,Cucurbita moschata D.was closer to Cucurbita pepo L.,and the two were more distantly related to Cucurbita maxima D.,which could provide scientific basis for the conservation of pumpkin germplasm resources and variety innovation.The DNA fingerprint map of pumpkin based on the ISSR molecular marker technology could provide a new way for the identification of pumpkin varieties.

Abstract:In order to explore the characteristics of nutritional content of different foxtail millet varieties from Longzhong area in Gansu Province,establish a standard evaluation system of nutritional quality and screen the foxtail millet varieties with excellent nutritional quality,10 foxtail millet varieties from Longzhong area(Huining County,Baiyin City)in Gansu Province were used as materials,19 nutritional quality indexes including basic nutrients(moisture,ash,carbohydrate,protein,crude fat,starch,amylose,amylopectin contents and amylose/amylopectin),functional nutrients(flavone,total phenol,crude polysaccharide contents)and mineral elements(Zn,Mn,Cu,Fe,Ca,Mg,Se contents)were measured,and principal component analysis and membership function methods were used to evaluate the nutritional quality of foxtail millet.The results showed that there was significant difference in the contents of 18 nutritional components excluding moisture content from 10 foxtail millet varieties,with variation coefficients ranging from 1.58％to 103.46％,which indicated that there was great difference in the individual nutritional quality index among different foxtail millet varieties.Protein,amylose,polysaccharide,Mg,Se and Zn contents were determined as core indexes for the evaluation of nutritional quality of foxtail millet by principal component analysis,correlation analysis and cluster analysis.The nutritional quality evaluation model was established by principal component analysis,and the top three foxtail millet varieties were M-8(Longgu 23),M-10(Longgu 029)and M-9(Longgu 032)based on the comprehensive score of nutritional quality,consistent with the results of the membership function evaluation,which indicated that these three varieties had better nutritional quality.Ten foxtail millet varieties could be divided into three categories by cluster analysis,and class Ⅱ included M-8 and M-9,whose comprehensive nutritional quality performed better.

Abstract:Porcine epidemic diarrhea(PED)caused by porcine epidemic diarrhea virus(PEDV)is an acute,highly contagious,enteric disease of pigs with high morbidity and mortality,thereby bringing huge economic losses to the pig industry all over the world.A better understanding of PEDV's genome and function is key to developing an effective and safe vaccine.By understanding PEDV's genomic structure,the proteins it encodes,and its interactions with host cells,researchers can design more targeted vaccine candidates.Advances in PED diagnostic technology are essential for early diagnosis and monitoring and evaluation of post-immune response.In this review,we summarized the latest progress of PEDV genome structure and function including S,E,M,N,accessory proteins and non-structural proteins,serology and molecular diagnostic methods,such as enzyme-linked immunosorbent assay,polymerase chain reaction,ring-mediated isothermal amplification,viral neutralization and indirect immunofluorescence assays,immunochromatographic tests,fluorescent microsphere immunoassays,sequence assays and clustered regularly inter spaced short palindromic repeats(CRISPR)-Cas,in order to provide ideas for establishing rapid and effective PEDV detection methods,and provide reference for effective prevention and control of PED in practice.

Abstract:To investigate the soil environment and growth characteristics of feed crops under different types of surface mulching,feed corn(C)and feed sorghum(S)were used as materials.Three types of mulching materials,namely permeable plastic film(1),ordinary plastic film(2),and biodegradable plastic film(3),were used for planting.The growth characteristics,biological yield,soil temperature and humidity,nutrients,and enzyme activity of the two crops were measured.The results showed that the plant height and SPAD values of C3 and S3 treatments were lower than those of other treatments.The fresh grass yield of C1 and C2 treatments significantly increased by 23.01％and 26.56％respectively compared to C3 treatment,while the fresh grass yield of S1 and S2 treatments significantly increased by 18.61％and 24.70％respectively compared to S3 treatment.Compared with other treatments,both C3 and S3 treatments generally reduced soil moisture content and temperature.The organic matter and alkaline nitrogen content in C1 and C2 treatments were significantly increased by 14.19％,14.62％,17.64％,and 19.86％,respectively,compared to C3 treatment.The organic matter and alkaline nitrogen content in S1 and S2 treatments were significantly increased by 13.08％,9.63％,38.19％,and 36.32％,respectively,compared to S3 treatment.The activity of soil catalase and sucrase showed the order of C2＞C1＞C3 and S1＞S2＞S3,and both C2 and S1 treatments were significantly higher than other treatments.In summary,ordinary plastic film is suitable for planting feed corn in arid areas of Ningxia,while permeable plastic film is suitable for planting feed sorghum.

Abstract:The aim is to explore the influence of different formula fertilization and fertilization techniques on leaf mineral nutrients,soil enzyme activity,soil effective nutrient content and fruit quality of Carya illinoensis.Five treatments for different formula fertilization tests,namely OPT(Nutrient experts systematically recommend fertilization),OPT-N(No nitrogen fertilizer),OPT-P(No phosphorus fertilizer),OPT-K(No potassium fertilizer)and CK(No fertilizer),respectively;five treatments were designed for different fertilization techniques,according to time,frequency and proportion and fertilization method.Mineral nutrient,soil enzyme activity,effective nutrient content,oil content and fatty acid content were determined in different periods.Different formula fertilization significantly changed the soil enzyme activity,soil effective nutrient content,plant leaf mineral nutrient content and fruit quality,among which the OPT-P and OPT-K treatments had higher soil nutrient absorption and utilization efficiency.Soil phosphatase and urease activities were higher in OPT-P,sucrase was higher in OPT,and catalase was higher in OPT-N.The oil content of OPT-P fruit kernels was significantly increased by 8.23 percentage points over the CK treatment,and there was no significant difference in unsaturated fatty acid content among the treatments.The soil effective N,P,K content and organic matter content with different fertilization techniques were significantly lower than the control treatment,and fertilizing 70%in early March and 30%in early June could improve the leaf nutrient content of N,P,and K,soil sucrase and catalase activities,the oil rate of fruit kernels was 7.38 percentage points higher than the control.In summary,OPT-P formula fertilization and twice from the shallow to the deep radial ditch can promote the soil nutrients and increase the oil content of fruit kernels.

Abstract:Under drought stress,50 mg/L chitosan oligosaccharides with different molecular weight(1 197,1 428,1 990 u)were sprayed to explore the effects of chitosan oligosaccharide with different molecular weight on the growth and physiological characteristics of maize seedlings,so as to provide a theoretical basis for the application of chitosan oligosaccharide with different molecular weight in production under drought stress.The results showed that under normal water condition,spraying chitosan oligosaccharide could promote the growth of maize seedlings.Under drought stress condition,spraying chitosan oligosaccharide could alleviate the impact of drought stress on the growth of maize seedlings.Among them,the plant height of treatments with chitosan oligosaccharides with small,medium and large molecular weight increased by 8.55%,9.37% and 5.80%,the stem diameter increased by 10.99%,5.23% and 1.31%,the dry weight of the aboveground part increased by 28.27%,38.82% and 19.83%,the dry weight of the underground part increased by 44.44%,39.58% and 29.17%,the leaf area increased by 43.45%,65.79% and 24.51%,the number of root branches increased by 114.57%,104.84% and 102.33%,the chlorophyll content increased by 43.07%,49.42% and 36.49%,the net photosynthetic rate(Pn)increased by 12.70%,22.49% and 6.80%,the content of superoxide anion decreased by 25.88%,35.74% and 21.83%,the activity of ascorbate peroxidase(APX)increased by 18.77%,29.92% and 11.43%,and the activity of glutathion peroxidase(GPX)increased by 23.30%,11.17% and 16.51%,respectively.Overall,under drought stress condition,spraying chitosan oligosaccharide with small molecular weight had the best effect on promoting the growth of the underground part,while spraying chitosan oligosaccharide with medium molecular weight had the best effect on promoting the growth of the aboveground part.The comprehensive evaluation results showed that the treatment with chitosan oligosaccharide with low molecular weight had the highest comprehensive score,followed by the treatment with chitosan oligosaccharide with medium molecular weight.

Abstract:In order to understand the preparation process of tobacco straw-based activated carbon and its effect on the pore structure,taking the tobacco straw as the carbon source,and the structure and morphology of tobacco straw-based activated carbon were characterized by BET surface area detection method,scanning electron microscope(SEM),X-ray photoelectron spectroscopy(XPS)using specific surface area,total pore volume and microporosity as the investigated indexes.The results showed that the surface morphology and pore structure of activated carbons prepared with different activators differed considerably,and the types of functional groups were basically the same,but the content and proportion varied.Activation temperature had a greater influence on surface area and total pore volume,while the main factor influencing microporosity was activation time.The optimum process conditions were obtained:KOH as activator,material ratio(tobacco straw∶activator,mass ratio)of 1∶2,impregnation time of 12 h,activation temperature of 800 ℃,activation time of 60 min.The specific surface area of the optimum tobacco straw-based activated carbon prepared was 1 980.91 m2/g,the total pore volume was 1.215 1 cm3/g,and the microporosity was 66.66％.Adsorption of β-phenylethanol by optimal tobacco straw-based activated carbon reached 101.49％,and the desorption rate was 35.78％at 35 d.The pore structure of the tobacco straw-based activated carbon prepared under the optimal conditions is well developed,with a rich variety of functional groups and good adsorption performance,which provides theoretical support for the multi-purpose utilization of tobacco straw waste and the preparation of high-performance tobacco straw-based activated carbon.

Abstract:Edible fungi cultivation is the fifth-largest planting industry in China and an important pillar for rural revitalization.When the edible fungi industry is developing rapidly,a large amount of spent mushroom substrate(SMS)is generated.A lot of SMS is casually discarded or incinerated,resulting in serious environmental pollution and resource waste.Therefore,the issue of the resource-based utilization of SMS has received widespread attention.Based on the analysis of the source,physical and chemical properties,and nutritional components of SMS,this paper comprehensively reviews the current situation and research progress of the resource-based utilization of SMS.This includes SMS being used as energy materials,for the production of bio-fertilizers,for improving the soil environment,for the extraction of bioactive substances,and for the manufacture of composite materials,etc.It also points out the existing problems in the utilization of SMS.Combining with the development status of the edible fungi industry,this paper looks ahead to the comprehensive utilization of SMS,aiming to increase the utilization rate of SMS and promote the sustainable development of the edible fungi industry.

Abstract:The main purpose of the present study is to understand the resistance to stripe rust and the utilization of stripe rust resistant genes in current bred wheat varieties,and find the varieties containing novel stripe rust resistant loci.Totally,480 domestic and foreign wheat germplasms were collected from various planting regions.The varieties were inoculated with mixed races of CYR32,CYR33 and CYR34 for testing the adult plant resistance.Simultaneously,the resistance to leaf rust and powdery mildew was investigated in infected field.The KASP markers closely linked or co-segregated with stripe rust,leaf rust and powdery mildew genes,Yr18/Lr34/Sr57/Pm38(7DS),Yr29/Lr46/Pm39/Sr58(1BL)and Yr30/Lr27/Sr2/Sb3(3BS),were selected for identifying the previous reported pleiotropic resistant genes.The results showed that there were 35(accounting for 7.29%)germplasms showed immunization to CYR32,CYR33 and CYR34,while the numbers of high-resistant and medium-resistant germplasms were 69(14.38%)and 79(16.46%),respectively.And the other 297(61.88%)germplasms demonstrated medium-or high-susceptible to the inoculated races.There were 13,10 and 7 germplasms containing the Yr18,and Yr29 and Yr30 genes,respectively;only 3 germplasms contained two of the resistant genes;no germplasm was detected with all the three resistant genes.In conclusion,183(accounting for 38.12%)germplasms showed resistant to stripe rust at adult plant stage,and 27 germplasms were detected with the above resistant genes.Yr18 or Yr30 gene showed resistant to the current races of stripe rust,however,the resistance level of Yr29 gene was partly lost at adult plant stage.

Abstract:To clarify the species and functionality of culturable microorganisms in domestic cigar tobacco leaves,cured cigar tobacco leaves from Wuzhishan,Hainan Province(variety Haiyan 103)and and from Dazhou,Sichuan Province(variety Chuanxue No.1)were used as experimental materials.The culture-dependent method were employed to isolate microorganisms,which were subsequently identified through molecular sequencing.The enzyme and aromatic substances production abilities of the isolated microorganisms were investigated.The results showed the isolation of 52 different bacterial strains from Haiyan 103 and Chuanxue No.1 cigar leaves,belonging to five different families:Bacillaceae,Planococcaceae,Erwiniaceae,Enterobacteriales,and Moraxellaceae.Bacillus subtilis E-11,isolated from Hainan tobacco,exhibited the highest protease and pectinase activities of 85.02 U/mL and 256.71 U/mL,respectively.Additionally,four yeast strains were isolated from Hainan tobacco leaves,namely one strain from Pichia,one strain from Rhodotorula,and two strains from Debaryomyces.These yeast strains did not produce extracellular protease and pectinase,and Pichia sp.J-2 demonstrated the ability to metabolize 2-phenylethanol.The highest yield of 2-phenylethanol,333.81 mg/L,was observed after 72 h of fermentation.In conclusion,cigar tobacco contains a rich variety of culturable microbial resources.Bacillus subtilis E-11 and Pichia sp.J-2,isolated from Haiyan 103,show promising potential for degrading macromolecular substances and enhancing the aroma content in tobacco leaves.

Abstract:Pepper is an important horticultural crop.Pepper mild mottle virus(PMMoV)threatens pepper and other solanaceous crops'production.In order to improve the prevention and control efficiency of PMMoV,this study designed specific RAA primers based on the conserved sequence of its gene encoding coat protein(CP)to achieve rapid isothermal amplification of PMMoV based on recombinase-aided amplification(RAA).And crRNA was designed to target the RT-RAA amplification products based on the CRISPR/Cas12a system.The RT-RAA-CRISPR/Cas12a system was optimized,and the results showed that the strongest signal was observed in the total system at a final concentration of 400 nmol/L for reporter gene FQ,and a ratio of 1∶5 for Cas12a∶crRNA at the final concentrations of 200 nmol/L and 1 000 nmol/L.The final RT-RAA amplification reaction and CRISPR chromogenic reaction each only took 15 min,and the positive signal could be directly observed under portable blue light irradiation equipment.This method could specifically detect PMMoV,and the detection limit of RNA of pepper samples carrying PMMoV could reach 1.34 pg/μL,which was 1 000 and 10 times more sensitive than that of conventional RT-PCR and real-time RT-PCR.The detection results of 30 samples showed that the RT-RAA-CRISPR/Cas12a assay established in this study could detect PMMoV in leaves,fruits and soils of infected pepper and tomato plants.The established detection system could be used for rapid and sensitive visual detection of pepper mild mottle virus.

Abstract:Nitrogen deposition,as a critical ecological factor in the soil ecosystem,significantly affects the structure and function of ecosystems.To systematically elucidate the impact of nitrogen deposition on soil respiration,the effects of nitrogen deposition on soil root respiration,soil microorganism respiration,soil animal respiration and chemical oxidation of soil carbon-containing minerals were reviewed,and the specific effects of different nitrogen deposition gradients on soil respiration were analyzed.In order to provide a theoretical reference for subsequent in-depth monitoring and research of soil respiration and related life activities,the future research directions in the field of soil respiration were prospected.

Abstract:To study the auxin response factor(ARF)gene family in tree peony,the gene family was identified and bioinformatics analysis was conducted.The results showed that a total of 19 ARF genes were identified in P.sufruticosa'Shima Nishiki',P.ostii and P.sufruticosa'Luoshen Xiaochun',and the ARF gene family members of tree peony were divided into four subfamilies based on the evolutionary classification of Arabidopsis thaliana ARF gene family,and according to the phylogenetic tree,there was a close evolutionary relationship between peony and Arabidopsis thaliana ARF homologous genes.There were differences in the length and isoelectric point of ARF proteins among different tree peony cultivars.All PsARFs contained conserved B3 and Auxin_resp domains,and most PsARFs also contained Aux/IAA domains.Conserved motif analysis showed that the number of Motif was 4-12,and gene structure analysis showed that the number of introns in the ARF gene of peony was 1-19,and there were some differences in the number of Motif and introns among different subfamilies.Tissue expression characteristics analysis showed that all PsARF genes were expressed in roots,stems and leaves of peony tissue culture seedlings,except that PsARF2b was not expressed in various tissues,but the expression levels in different tissues were very different.The expression levels of PsARF7,PsARF19,PsARF8a,PsARF8b,PsARF6,PsARF11a,PsARF 11b,PsARF9,PsARF 16b,PsARF17,PsARFx were the highest in roots,PsARF 5,PsARF 3 and PsARF 4 were the highest in stems,and PsARF2a,PsARF 1,PsARF16a and PsARF 10 were the highest in leaves.

Abstract:In order to investigate the effect of mechanical properties of flue-cured tobacco on the quality of threshing and redrying processing,C3F grade tobacco leaves produced from three production areas,Chenzhou in Hunan Province,Bijie in Guizhou Province and Sanming in Fujian Province were selected to analyze their mechanical properties,the area distribution and shape characteristics of the tobacco leaves after threshing and redrying processing were tested,and the relationships between the mechanical properties and the quality indicators of the tobacco leaves were analyzed using relevant analysis.The results showed that other mechanical indicators of tobacco leaves from three different production areas showed significant differences,except for tensile strength,elongation,and stem content.Tobacco leaves in Chenzhou had higher shear strength and penetration strength,tobacco leaves in Bijie had the highest adhesion force,while tobacco leaves in Sanming had higher leaf stem binding force and branch binding force.The overall area of tobacco leaves in Chenzhou was relatively larger,with a high proportion of area over 500 mm2.Tobacco leaves in Bijie had good uniformity,with a high proportion of tobacco with an area of 300-500 mm2.The area of tobacco leaves in Sanming was relatively smaller,the proportion of tobacco with an area of less than 300 mm2 was significantly higher than other areas.There were no significant differences in rectangularity,thinness,and circularity.The proportion of lamina area distribution in different production areas showed a trend of first increasing and then decreasing with the increase of lamina area,and the difference in shape characteristic indicators(Xc)was not significant,with slight differences in the proportion peak value.Among them,tobacco in Bijie had the highest proportion peak value with a rectangular degree of 0.63 and a contour temperature characteristic value of 3.75,while tobacco in Sanming had the highest proportion peak value with a circular degree characteristic value of 2.79.There was no significant difference in the proportion peak value of ellipticity characteristic values among different areas of tobacco.The characteristic area of tobacco was significantly positively correlated with shear strength,was weakly correlated with tensile strength,adhesion,stem ratio,and strongly correlated with other indicators;The uniformity coefficient was significantly negatively correlated with tensile strength,strongly correlated with adhesive strength,weakly correlated with extensibility,stem ratio,stem binding force,and not correlated with other indicators;The rectangularity,slenderness,and contour temperature of tobacco had no correlation with branch adhesion,roundness had no correlation with stem ratio,while other mechanical indicators had certain impact on them.In summary,tobacco leaves from Chenzhou,Hunan had strong processing resistance and a relatively larger overall area.Tobacco leaves from Bijie,Guizhou had good uniformity in area and were mostly irregular in shape.Tobacco leaves from Sanming,Fujian had strong stem and branch binding force,but the overall area was relatively smaller.

Abstract:The plant height(PH),ear height(EH),stem rind penetrometer resistance(RPR).internode diameter(ID)and internode length(IL)were investigated under multiple environments with 145 maize inbred lines from home and abroad as materials.The excellent inbred lines with strong stem lodging resistance were screened out through correlation analysis,principal component analysis and cluster analysis,so as to provide excellent germplasm resources for maize lodging resistance breeding.The results indicated that PH,EH,RPR,ID and IL were extremely significantly different among different maize inbred lines.The heritability of PH with 0.99 was the highest,followed by EH and RPR all with 0.97.The correlation analysis results showed that RPR was extremely significantly positively correlated with PH.The principal component analysis results showed that the first three principal components represented 77.02％of the information of the five traits of 145 maize inbred lines,and their contribution rates were 37.08％,21.94％and 18.00％,respectively.Based on the comprehensive evaluation and cluster analysis of lodging resistance of each inbred line,145 inbred lines were divided into 6 groups,13 inbred lines with strong lodging resistance,such as S268,S1 12,S135,S270,etc,were screened out.