To investigate the effects of row spacing and chlormequat chloride application on lodging resistance and yield performance of foxtail millet in Southeastern Shanxi,a two-factor randomized block design was employed,utilizing Jingu 21 as the experimental material.The experimental design included three row spacing levels(30,40,and 50 cm,designated as D30,D40,and D50,respectively)and three chlormequat chloride treatment regimes:spraying with water only(CK),single application at the six-leaf stage(T1),and sequential applications at both the six-and eight-leaf stages(T2).This resulted in a total of nine treatment combinations.The study evaluated the impacts of these treatments on stem morphological characteristics,lodging incidence,grain yield,and its component traits.Results showed that chlormequat chloride application under varying row spacing conditions significantly improved stem breaking resistance while significantly reducing plant height,center-of-gravity height,and field lodging rate.The D40+T2 treatment exhibited the highest stem breaking resistance(94.59 N)and concurrently achieved the lowest values for plant height(161.53 cm),center-of-gravity height(80.3 cm),and lodging rate(16.31%).In terms of yield,as row spacing increased,the yield of CK,T1,and T2 treatments all showed a decreasing trend.Among them,the D30+T1 treatment achieved the highest yield of 4 923.83 kg/ha.Correlation analysis indicated that under different row spacing and chlormequat treatments,millet yield was mostly positively correlated with plant height and panicle traits,while consistently negatively correlated with lodging rate.This demonstrates that optimizing row spacing and chlormequat application can effectively regulate key agronomic traits.In conclusion,optimizing row spacing along with appropriate chlormequat treatment can effectively minimize the risk of lodging while maintaining yield.The D30+T1 treatment demonstrated superior overall performance and is therefore recommended for broader adoption in foxtail millet cultivation in Southeastern Shanxi.

To explore the relationship between soil bacterial community diversity and soil enzyme activity of Qinqiong(Q) and Magnum(M) under salinity stress treatment,the bacterial community structure and soil enzyme activity of Qinqiong and Magnum for 0,6,12,24,48 h were compared and analyzed by using high-throughput sequencing of bacterial 16S rRNA and colorimetry.The results indicated that at the phylum level,the relative abundances of Actinobacteria and Proteobacteria in the rhizosphere soil of Qinqiong were higher than those in Magnum.At the genus level,the relative abundances of Bacillus and Arthrobacter in the rhizosphere soil of Qinqiong were greater than those in Magnum,while the relative abundance of Pseudomonas was lower compared to Magnum.After 48 hours of saline-alkali stress,the activities of soil polyphenol oxidase(S-PPO),soil catalase(S-CAT),soil dehydrogenase(S-DHA),and soil invertase(S-AI) in the rhizosphere of Qinqiong were 1.32,1.53,1.38,and 1.28 times higher than those of Magnum,respectively.Furthermore,the S-CAT activity exhibited a significant positive correlation with the bacterial ACE and Chao diversity indices.Qinqiong may influence changes in bacterial community structure by altering the relative abundances of dominant bacterial groups,thereby enhancing the bacterial community diversity index and soil enzyme activity.In contrast,the changes in the bacterial community within the rhizosphere of Magnum were not significant.The diversity of soil microbial communities is a critical factor determining the saline-alkali tolerance of oat varieties.

In order to better solve the problem of false positive in the detection of Aphelenchoides besseyi Christie and establish a stable,efficient and low cost detection system for millet seed of parasitic nematodes,using millet seed of nematodes Jigu 20 as experimental materials,the number of nematode eluted by medical cotton gauze,coarse nylon gauze and thin nylon gauze was compared.Three effect methods of DNA extraction,namely,cutting,freeze-thaw,enzymatic lysis were designed and compared in order to check their efficiency of DNA extraction from singlenematode.A total of 109 millet seed samples from different seed companies in 2018,2020 and 2021 were detected by the system.The final detection system was as follows:1.5 g seeds were wrapped in thin nylon gauze and soaked for 4 h,then the elution was mixed and counted under microscope for nematode quantification; the single nematode DNA was extracted by enzymatic lysis and characterized by PCR amplification with specific primers.The pathogenic nematodes were molecular-identified as Aphelenchoides besseyi.A total of 4 seed samples from 109 millet seed samples with 5 nematodes per 1.5 g were detected.The system with nematode quantification and qualification can be used for rapid detection of nematodes in large quantities of millet seed,providing technical support for the early diagnosis,monitoring,and prevention and control of millet nematode disease.

Drought during the grain filling period can seriously affect the later growth and development of foxtail millet plants,as well as the morphogenesis,yield,and quality of grains.To analyze the effects of drought during the grain filling period on the later growth and development of foxtail millet,as well as the morphogenesis of grains,and to provide a theoretical research basis for the molecular mechanism of foxtail millet starch regulation in response to drought stress,it investigated the effects of different degrees of drought during the grain filling period on the agronomic and grain quality traits of foxtail millet using Jingu 21 as the material.Simultaneously,Real-time Quantitative PCR was used to analyze the response of key genes SiAGPase1(Glucose pyrophosphorylase)and SiSSS1(Starch synthase)to drought during starch synthesis.The results showed that drought had significant effects on fresh weight per plant,fresh weight per root,fresh weight per panicle,panicle weight,grain weight per spike,grain weight per thousand grains,main stem diameter,subpanicle internode length,chlorophyll content,seed setting rate,spike code density and other agronomic characters.The more severe the stress,the greater the degree of reduction.The analysis of grain composition showed that drought can reduce the content of fat,crude protein,peak viscosity and final viscosity.The more severe the stress,the greater the reduction degree.Gene expression analysis showed that the expression levels of SiAGPase1 and SiSSS1 changed sharply during the grain filling period under drought stress.The results revealed that SiAGPase1 and SiSSS1 played an active role in regulating the balance between starch decomposition and starch accumulation in grains under drought stress in order to adapt to plant response to drought stress.

Salt stress causes a significant threat to crop yield and quality.As one of the pioneer crop species in salt tolerance research,barley holds critical significance;the exploration of its salt tolerance mechanisms is capable of providing a theoretical foundation for crop salt-tolerance breeding programs.Two naked barley landraces,namely B87 with salt-sensitivity and B94 with salt-tolerance,were employed as experimental materials.At the three-leaf stage,their seedlings were exposed to a 200 mmol/L NaCl treatment for 7 days.Subsequent to the treatment,the above-ground tissues were collected for transcriptomic and metabolomic sequencing.By means of integrated multi-omics analysis,this study was designed to elucidate the molecular mechanisms governing salt tolerance in naked barley.The results demonstrated that 2 240 differentially expressed genes (DEGs) and 198 differentially abundant metabolites (DAMs) were identified in B87 via transcriptomic and metabolomic profiling,whereas 923 DEGs and 232 DAMs were detected in B94.Venn diagram analysis further revealed that the salt-tolerant naked barley B94 contained 480 specific DEGs and 129 specific DAMs.Furthermore, GO and KEGG analyses were separately performed on the DEGs and DAMs. And the DEGs of B94 were significantly enriched in 11 unique pathways, while its DAMs were only significantly enriched in 1 unique pathway. In addition, correlation analysis between the transcriptome and metabolome was conducted, and it was found that the changes in genes and metabolites exhibited both consistency and inconsistency. These research efforts not only enhance the current understanding of the molecular mechanisms underlying salt tolerance in naked barley,but also provide valuable insights and candidate targets for the development of salt-tolerant naked barley cultivars in future breeding.

To investigate the function of the β-glucosidase(βGlu)gene PgβGlu4 from Pyrenophora graminea,which previous studies found to be highly expressed during the infection stage,we constructed a subcellular localization vector of PCE2-EGFP-PgβGlu4 and transformed rice protoplasts,observed the fluorescence distribution and analyzed its location of existence.Simultaneously,the PgβGlu4 gene RNAi vector was constructed,and QWC protoplasts were prepared by CaCl₂-PEG4000 mediated method for genetic transformation.The function of PgβGlu4 gene was studied by detecting the vegetative growth and pathogenicity of the RNAi mutants.Phylogenetic analysis of PgβGlu4 and other homologous proteins from different pathogens showed that PgβGlu4 had a closer evolutionary relationship with that from Pyrenophora tritici-repentis.The subcellular localization results showed that PgβGlu4 was mainly localized in the nucleus and cell membrane.Four PgβGlu4 gene RNAi mutants were verified by hygromycin.qRT-PCR analysis showed that the expression of PgβGlu4 gene in four RNAi mutants decreased by 66.31%,68.60%,54.37% and 69.89%,respectively,compared with the wild isolate.The colony diameter was smaller than that of the wild isolate,and their incidence rate was reduced by 56.69,52.76,47.43,and 53.30 percentage points.After infection with the mutant strain of RNAi-PgβGlu4,the relative chlorophyll content in barley leaves ranged from 30.3 to 35.0,which was significantly higher than that of the wild-type group.The effect of PgβGlu4 gene silencing on the height of barley plants before and after infection was significant compared with that of the wild-type.The results indicated that the PgβGlu4 gene was involved in the regulation of the growth,development,and pathogenicity of Pyronophora graminea.

In order to explore the relationship between MrAGL8 gene and pod dehiscence traits in Medicago ruthenica. In this study,Medicago ruthenica was used as the plant material.The MrAGL8 gene was amplified by PCR,cloned,and sequenced.Additionally,bioinformatics analysis,subcellular localization,and expression analysis in different tissues and organs were performed for this gene.The results showed that the complete coding region of MrAGL8 cDNA with a length of 711 bp was obtained through cloning using PCR amplification technology.Bioinformatics analysis results showed that MrAGL8 encoded 236 amino acids,it had MADS-box and K-box protein conserve domains.Its molecular weight was 27.39 ku,the theoretical isoelectric point was 8.69,the total number of positively charged residues was 39,the total number of negatively charged residues was 36,and the instability coefficient was 48.5.The secondary structure of the protein contained α-helix and β-sheet.It was an unstable protein and belonged to a hydrophilic alkaline protein.Subcellular localization results showed that MrAGL8 protein was located in the nucleus.The expression analysis of different tissues and organs showed that the expression level of MrAGL8 in different tissues was stem>root>pod>leaf>flower,and the expression levels of roots and stems were significantly different from those of leaves,flowers and pods.The results showed that MrAGL8 gene was related to pod dehiscence.

Chalcone synthase(CHS)is the initial and crucial enzyme in the flavonoid biosynthesis pathway,responsible for the synthesizing of metabolites such as flavones,flavonols,isoflavones,and anthocyanins,which play a vital role in enhancing plant stress resistance.In order to explore the role of CHS genes in the drought stress response of oat seedlings,it identified a CHS gene from the full-length transcriptome data of oats,named AsCHS.Gene cloning,bioinformatics analysis,subcellular localization,and expression pattern analysis were conducted.The results showed that the AsCHS gene encoded a protein composed of 398 amino acids and had a CHS family-specific tag sequence.This protein was hydrophobic and unstable.It was a non-transmembrane protein and was located in the nucleus and cytoplasm.Secondary structure prediction showed that AsCHS was mainly composed of α-helices and random coils.The analysis of the cis-acting elements within the promoter region revealed that the gene contained cis-elements associated with drought stress response and multiple hormone signaling pathways.Phylogenetic tree analysis showed that AsCHS was closely related to its counterparts in Lolium perenne,Poa annua,and Deschampsia antarctica.Subcellular localization indicated that the AsCHS protein was localized in the nucleus and cytoplasm.Compared with the control group,the expression pattern of AsCHS in oat seedlings under drought stress changed from fluctuating expression to incremental expression with different germination time,shifting from the highest expression level in roots to the highest in leaves,with significant differences observed in leaves expression.It laid a foundation for elucidating the function of AsCHS in the drought stress response of oats.

In order to explore the production performance and soil improvement effect of sweet sorghum in saline-alkali land,Zhongketian 438 sweet sorghum was planted in Southern Xinjiang,and its yield was measured,in addition,0-10 cm,10-20 cm,20-30 cm soil layers were selected on saline-alkali land before planting and after harvesting of feed sweet sorghum varieties,and the effects of soil physical and chemical properties,soil ions and soil enzyme activities were measured and compared.The results showed that the total salinity,pH value and electrical conductivity of the soil decreased after the planting of sweet sorghum.Compared with before planting,the contents of Na⁺,K⁺,HCO₃^-,Cl^-and SO₄^2- and total potassium,total phosphorus,available phosphorus and available nitrogen decreased significantly,while the contents of Ca²⁺,Mg²⁺,total porosity,organic matter,total nitrogen and available potassium increased.The content of Mg²⁺ in soil cation was highest,and the content of SO₄^2- in anion was the higher than that of Cl^-.In soil enzyme activity,the activities of catalase,sucrase and alkaline phosphatase were not significantly different,but the urease activity was significantly different.Compared with before planting,the change of 10-20 cm soil layer in different soil layers was more obvious.The results of correlation analysis showed that there was a significant positive correlation between pH value and total salinity;there was a significant negative correlation between bulk density and pH,total salinity;and a significant positive correlation between sucrase and alkaline phosphatase.The above results showed that the saline-alkali soil in this area is a soil type dominated by Na₂SO₄,and the cultivation of feed sweet sorghum in the saline-alkali soil in this area could not only harvest high-yield forage grass,but also reduce some ions in the soil to improve soil physical and chemical properties.

To select the suitable sorghum varieties for brewing in Qitai County,and provide reference for breeding and generalization of the new sorghum varieties in Xinjiang,20 new sorghum varieties were introduced from other provinces and their growth periods,agronomic traits and yields were compared to identify the highest and stable yield of each variety in 2020-2022.And the nutritional qualities such as grain starch,lysine,tannin,soluble total sugar,crude protein,crude ash and crude fiber were measured.The results showed that the growth period,agronomic traits,yields and nutritional composition were different between varieties and planting years.The average growth periods of 20 varieties were 84-146 days and plant heights ranged from 68.44 to 250.46 cm.The two species,Longza 18 and Longza 20,belonged to extremely early maturing and short varieties.The 13 short stem varieties with plant heights of less than 150 cm were identified as suitable for mechanized cultivation,such as Fengza 4,Liaonuo 11,Jiza 124,Jiza 127,Liaoza 37,Liaonian 3,Jiniang 3,Jinza 34,Jinnuo 3,Tongza 108,Jinza 109,Chiza 106 and Jinnuoliang 5.Hongyingzi was the only late-maturing high-stem variety.The yield ranged at 4 364.32-13 779.84 kg/ha,Jinza 109 had the highest yield while Shenza 5 had the lowest yield.There were differences in grain quality among different varieties;Liaoza 10 had the highest starch content of 759.93 g/kg while Jinza 34 had the lowest tannin content of 1.81 g/kg.In summary,based on the characteristics of growth period,agronomic traits,yield and quality,the tested short-stem and mid-mature variety Jinza 109 showed the highest yield,best stability and best comprehensive performance,which can be planted and popularized as the preferred variety suitable for mechanized cultivation in the Qitai area.

In order to further explore the genetic rule of grain and stalk yield of sorghum,grain sorghum Xinliang 52 and Sudan grass TS 185 were hybridized as parents to obtain F₂ and F_2∶3 populations,115 pairs of polymorphic primers were used to construct the genetic linkage map of 430 F₂ progeny populations by interval mapping.A total of 86 QTLs were detected for 12 agronomic traits,including number of tillers, number of blades, stem diameter, panicle length, plant height, stem fresh weight, whole plant fresh weight, shelling rate, panicle weigh, thousand kernels weight, grain weight per panicle and grain number per panicle, with LOD value as the threshold value.The QTL of stem fresh weight was located between sam17164-sam15397 on chromosome 1.On chromosome 2,the QTL of number of tillers was located in Xcup64-Xcup26 region,leaf was located in Xtxp019-sam01138 region,and stem fresh weight was located in Xcup26-Xtxp080 region.Panicle length QTL was located between sam44791 and sam33751 on chromosome 3.The QTL of shelling rate was located at sam39622-sam43980 on chromosome 7.The QTL for whole plant fresh weight located in sam10491-sam17740 on chromosome 8 and the QTL for number of tillers located in sam710901b-sam59778 on chromosome 10 were all newly detected loci.

Mitogen-activated protein kinase kinase (MAPKK or MKK) plays an important role in plant growth,development and stress responses.In order to identify MAPKK genes related to rust resistance in foxtail millet and provide candidate genes for the study of rust resistance mechanism and disease-resistant molecular breeding of foxtail millet,the members of MAPKK gene family (SiMKKs) in foxtail millet were identified and analyzed at the whole genome level by bioinformatics methods.Real-time PCR was used to detect the expression level of SiMKKs gene in different tissues,under the stress of rust fungus and exogenous hormone treatment.Excel,MEGA and DnaSP were used to analyze the variation sites and haplotypes of the SiMKKs gene related to rust resistance in 70 re-sequenced foxtail millet varieties,and the excellent rust-resistant haplotypes were identified based on phenotype analysis.The results showed that a total of 10 SiMKKs were identified in foxtail millet,which were distributed on 5 chromosomes.The number of exons ranged from 1 to 11,and the encoded protein contained 331-523 amino acids.The SiMKKs were divided into 4 groups.Groups A and B contained S/T-X₅-S/T motif,while SiMKKs in groups C and D did not have this motif.Conserved Motif 1-Motif 6 existed in all SiMKK proteins.The promoter region of each SiMKK gene contained 1 to 3 biotic stress-related cis-acting elements,such as defense and stress response,methyl jasmonate(MeJA) response,salicylic acid(SA) response and elicitor activation.Except SiMKK10-1 and SiMKK10-3,the other 8 SiMKK genes were expressed with different degrees in different tissues,and under rust infection,SA and MeJA treatments.The highest expression of SiMKK4,SiMKK5 and SiMKK10-2 were in roots at booting stage,and the highest expression of SiMKK6-1 and SiMKK6-2 were in stems at booting stage.The expression of SiMKK4 was up-regulated in the resistant response and down-regulated in the susceptible response within 24 h after inoculation,and its expression was related to disease resistance.The expression of SiMKK4 was up-regulated within 16 h and then down-regulatedafter SA and MeJA treatments,and showed continuous changes during SA treatment.In addition,the expression patterns of the remaining 7 SiMKK genes in SA and MeJA treatments were also consistent.The coding region of SiMKK4 gene contained 7 haplotypes and Hap_1 was the dominant haplotype,and no key variation sites related to disease resistance were found.In summary,the expression of SiMKK4 is identified to be associated with resistance to rust disease in foxtail millet,and SiMKK4 may participate in the early disease resistance response of foxtail millet through SA and MeJA signaling pathways.

In order to identify the differences in source-sink relationships among different types of barley and the main source-sink indexes affecting yield,four barley materials with large leaf area differences,GP6,GKP7,GK6 and C2-1,were selected to study the differences in photosynthetic characteristics,dry matter,soluble carbohydrates,and filling characteristics and their relationships with yield in 7—28 d after anthesis.The results showed that the length-to-width ratio of flag leaves of GK6 and GKP7 was lower than that of GK6 and C2-1,while the chlorophyll content,photosynthetic rate and soluble sugar of flag leaves and penultimate leaves were higher.The chlorophyll content of flag leaves and penultimate leaves of GKP7 decreased the most,while the decrease of GK6 and C2-1 was smaller.During the early stage of grain filling,the dry weight of leaves and stem sheaths in GK6 was the highest,but the dry matter decreased the most during the filling process.The dry weight of GP6 and GKP7 was lower than that of GK6 and higher than that of C2-1,but the decrease was relatively small throughout the filling period;the grain rapid weight gain time of GP6 and GKP7 was 7—21 d longer than that of GK6 and C2-1(7—14 d),and the average filling rate(R) and time of maximum filling rate(Tmax)of GP6 was the highest,and the soluble sugar content of stem sheath and grain was lower than that of C2-1 at the early filling stage,which was higher than that of other materials.GKP7 filling active periods(D) and maximum filling rate(Rmax)were the highest,soluble sugar content in stem sheath was lower than GP6 and C2-1 at the early grout stage,and higher than other varieties at the later grout stage of leaf and stem sheath.The soluble sugar content in all organs of GK6 was low,and the soluble sugar content in stem sheath and grains was the highest at the early stage of C2-1 filling,but the content decreased rapidly at 7—14 d and was lower at the later stage of filling.The number of thousand grains weight and yield of GK6 and GKP7 were significantly higher than those of GK6 and C2-1,and the sink capacity of GK6 and C2-1 was smaller.Grain weight per spike/leaf area was GKP7>GP6>C2-1>GK6.Correlation analysis showed that the ratio of flag leaf length to width was negatively correlated with yield,and the stem sheath and leaf dry weight,leaf soluble sugar content,number of grains per spike,grain weight per spike/leaf area were positively correlated with yield at maturity.The chlorophyll content and photosynthetic rate at 7 d after anthesis,the grain dry weight at 14—28 d after anthesis,R and Rmax were positively correlated with yield.In summary,GKP7 has the most reasonable source-sink relationship,with GP6 ranking second,C2-1 source and sink are small,and GK6 source is large and sink is small.The ratio of flag leaf length to width,chlorophyll content and photosynthetic rate at the beginning of filling,grain dry weight,maximum filling rate and average filling rate can be used as the main indexes for high yield breeding.

To reveal the distribution preferences of SSR in foxtail millet genome,the study analyzed distribution regularities of SSRs among the 5'-flanking regions,the 3'-flanking regions,the extron regions and the intron regions in gene locus from foxtail millet genome using bioinformatics methods.The results showed that the relative frequency,a ratio of the frequency of a type of SSR in a certain genomic region by the frequency of this SSR in whole genome,of SSRs decreased with increasing of the distance of 5'-flanking regions from start codon,and was more than 1.50 obviously in a range from 1 bp to 700 bp.However,the relative frequency of SSRs was close to 1.00 in each of other three regions.Furthermore,with increasing of the distance of 5'-flanking regions from start codon,the relative frequency of various SSR types revealed the various changing trends,and as a whole,6 SSR types,including CCG,AG,AGG,AGGG,ACC and AGC,showed both the high frequency and the high relative frequency,and of these 6 types,the distance range(1—1 800 bp)of AG,in which its relative frequency was more than 1.50,is the maximum while that of CCG is minimal(1—200 bp).Meanwhile,in the extron regions,5 SSR types with high C/G contents,including CCG,AGG,AGC,ACG and ACC,showed both a high frequency and a high relative frequency.It was concluded that SSRs distributed preferentially in a length range from about 1—700 bp of 5'-flanking regions with 6 main specific SSR types,including CCG,AG,AGG,AGGG,ACC and AGC;on the other hand,in 3'-flanking regions,the intron regions and the extron region,distribution of SSR is close to that in genome,and however,in the extron region,a total of 5 SSR types,including CCG,AGG,AGC,ACG and ACC,are obviously specifically distributed.

Leaf color mutant is an ideal material for studying C4 photosynthesis pathway and chlorophyll metabolism mechanism.In order to study the molecular mechanism of yellow-green leaf mutation in millet,and lay a foundation for the functional study of yellow-green leaf genes and the molecular mechanism analysis of chlorophyll metabolism,a stable hereditary yellow-green leaf mutant ygl7 was identified in the ethyl methacrylate(EMS)mutant library of Changnong 35.Agronomic traits,photosynthetic pigment content and photosynthetic parameters,and chloroplast ultrastructure observation were carried out on the mutant and wild type.At the same time,genetic analysis of mutant leaf color was performed,primary mapping was performed by BSA method,fine mapping was performed by an F₂ population,and candidate genes were predicted according to functional annotation combined with RNA-Seq.The expression pattern was analyzed by qRT-PCR,and the protein interaction was verified by yeast two-hybrid experiment.The results showed that the leaves of ygl7 were obviously yellow-green at seedling stage and elongation stage,and gradually turned to light green at heading stage compared with the wild type.The chlorophyll content and photosynthetic rate of ygl7 during the whole growth stage were significantly lower than that of the wild type,and the chloroplast structure was abnormal.Genetic analysis showed that ygl7 yellow-green leaf phenotype was controlled by a pair of recessive single genes.Yellow-green leaf gene was located in the 434.9 kb region of chromosome Ⅶ.Candidate gene analysis predicted that Seita.7G290300 encoding protoporphyrin Ⅸ magnesium chelatase Ⅰ was the candidate gene for regulating yellow-green leaf.The results of qRT-PCR showed that Seita.7G290300 was highly expressed in leaves,and the expression of Seita.7G290300 in mutant was lower than that of wild type.The expression levels of genes related to chlorophyll synthesis pathway(CHLD,CHLI)and photosystem(LHCB1,LHCB6)were down-regulated in the mutants.The experiment of yeast two-hybrid showed that SiYGL7 interacted with MORF2.

In order to explore the role of RPM1 in sorghum disease resistance,a sorghum SbRPM1 gene was obtained from sorghum smut resistant variety SX44B by homologous cloning method.The bioinformatics analysis results showed that the total length of the cDNA of SbRPM1 gene was 2 802 bp,encoding 933 amino acids,and its protein had a theoretical molecular weight of 106.1 ku and an isoelectric point of 7.11,which was a hydrophilic protein.The SbRPM1 protein had no transmembrane structure,and its subcellular localization was in the cytoplasm.Conservative domain analysis showed that SbRPM1 protein contained RX-CC-like,NB-ARC and LRR domains,and belonged to CNL proteins in the NLRs family.Phylogenetic analysis showed that SbRPM1 protein was most closely related to the RPM1 protein of Miscanthus lutarioriparius.The expression pattern of SbRPM1 gene was detected by Real-time quantitative PCR,and the results showed that the expression of SbRPM1 gene was higher in leaves and inflorescence,followed by roots,and the lowest in stem.The expression of SbRPM1 gene was significantly up-regulated at 24—72 h in disease-resistant varieties after inoculation with Sporisorium reilianum pathogen,suggesting that this gene could be induced by S.reilianum and played an important role in sorghum disease resistance.In this study, the CDS sequence of the SbRPM1 gene was cloned for the first time in sorghum, and the structure, nature and expression of the gene were characterized.

The identification of leaf shape mutant and genes controlling leaf shape can not only provide germplasm resources for genetic improvement of leaf shape,but also help to analyze the genetic regulation mechanism of leaf development.vrnl11 was identified from an EMS induced Wankelü 3(WK3)mutant library.Progeny populations derived from vrnl11/WK3 and vrnl11/Zhonglü 1 were used for genetic analysis,and the segregation pattern of different phenotypic plants in F₂ populations was determined by χ² test.Two F₂ populations constructed by crossing vrnl11 with Zhonglü 1 and Zhonglü 5 were used as mapping populations.Fine mapping for vrnl11 was completed by using BSA sequencing technology and map-based cloning strategy.Phenotype identification results showed that,compared with wild-type WK3,the leaf width and leaf area of vrnl11 decreased by 25.7% and 21.7%,respectively.Genetic analysis showed the narrow leaf phenotype of vrnl11 was controlled by a single recessive nuclear gene.BSA sequencing analysis located the mutation site within a 4.7 Mb interval from 15.0 Mb to the chromosomal end on chromosome 11.vrnl11 was finally located in the 186.5 kb interval between the markers nl-61 and nl-46 by using these newly developed polymorphic molecular markers.The mapping interval contained 9 predicted genes.These results provide a theoretical basis for cloning vrnl11 and understanding the molecular regulation mechanism of leaf development in mungbean.

To reveal the diversity characteristics of endophytic bacteria in different cultivars and organs,and clarify the correlation between endophytic bacteria community structure and host varieties,organ types and disease resistance and susceptible characteristics.Six different varieties of foxtail millet,Jigu 22,Honggu,Longgu No.11 and Xiaoqinggu,Shiliuzi and Nenxuan 16,which were resistant (susceptible) to Fusarium head blight,were selected as materials.The leaves,roots,stems,leaf sheaths and mature spikes of foxtail millet,were taken respectively.DNA was extracted for PCR amplification of 16S rDNA V3—V4 region,and Miseq library was constructed for high-throughput sequencing.Microbial diversity was analyzed by Major biological cloud platform.There were certain differences in endophyte species composition between susceptible and resistant varieties,the dominant populations of endophytes were Proteobacteria and Actinobacteriota,followed by Bacteroidota and Firmicutes,Myxococota and Chloroflexi were lower relative abundance followed by Gemmatimondota and Fusobacteriota.Alpha diversity analysis showed that the resistant cultivars had higher panicle community richness at leaf and maturity spikes and higher panicle diversity at leaf,root and maturity spikes.The susceptible varieties had higher richness of root and stem community and higher diversity of stem and leaf sheath;PCoA analysis showed that organ type had more effect on endophytic community structure than variety.Species composition analysis showed that the diversity of endophytic flora in foxtail millet was affected by different varieties and different parts,and the species of endophytic flora in different parts were quite different.The diversity of endophytic flora between susceptible cultivars Xiaoqinggu,Shiliuzi and Nenxuan 16 and resistant cultivars Jigu 22,Honggu and Longgu No.11 was quite different.The resistant cultivars had NB1-j in leaf sheath stage,and the ears had Acidobacteriota in mature stage.The study showed that the diversity and community structure of endophytic bacteria were affected by different organs and varieties of the foxtail millet,and the organ types had more influence on the community structure of endophytic bacteria than varieties.

In order to screen chemical control agents that can effectively reduce millet plant height and improve its lodging resistance,as well as the optimal spraying period,and explore the effects of different chemical control agents on millet growth,development,and yield,four chemical control agents (paclobutrazol,Menthylamine,cynanchon,and uniconazole)were sprayed on Nenxuan 17 during the seedling and jointing stages.The dry matter accumulation, SPAD, net photosynthetic rate, stem characteristics and yield components of each treatment plant were measured during the filling and mature stages.The results showed that spraying uniconazole,chlorpyrifos,chlorpyrifos,and paclobutrazol during the seedling and jointing stages of foxtail millet could dwarf plants to varying degrees,increase stem diameter,improve lodging resistance,and achieve yield increase.Among them,the plant height and internode length of foxtail millet decreased by 6.76% and 25.43% respectively compared to CK during the seedling stage.Spraying chloramphenicol had the most significant effect on increasing stem diameter during the seedling stage,which was 22.89% higher than CK.The foxtail millet had the best lodging resistance under the spraying of foxtail millet,and the spraying of foxtail millet had the most significant effect on increasing yield during the seedling stage,which was 17.51% higher than CK;all four regulators could significantly increase the SPAD value and net photosynthetic rate of millet leaves.Spraying paclobutrazol at the seedling stage had the best effect on improving the SPAD value and net photosynthetic rate,with an increase of 35.29% and 30.37% respectively compared to CK;spraying chemical control agents had no significant effect on the accumulation of aboveground dry matter in millet plants compared to CK.Overall,spraying paclobutrazol during the seedling stage had the best effect and could be applied as a suitable chemical control and lodging resistance measure for high-yield cultivation of millet.

To scientifically and accurately identify foxtail millet germplasm resources,strengthen the management of millet germplasm resources and protect new varieties.33 pairs of SSR markers were selected to establish molecular identity cards for 94 foxtail millet germplasm resources.A total of 500 SSR markers covering 9 linkage groups of foxtail millet chromosomes were screened,of which 33 markers showed polymorphic bands and stable amplification,these markers were used to establish molecular ID of 94 foxtail millet varieties.A total of 203 polymorphic bands were obtained.The number of alleles revealed by each marker was 3—10 with an average of 6.2.The polymorphism information content(PIC)values for the SSR loci ranged from 0.429 to 0.864 with an average of 0.740.Ten markers,including b185,b260,b224,b103,b225,CAAS1044,b186,b253,b105 and CAAS3008,were identified to be efficient in the variety ID construction.The IDs of 94 foxtail millet varieties were established by the 10 pairs of markers,which could clear distinguish all the varieties tested.

By investigating the effects of chemical fertilizer reduction with humic acid bio-fertilizer on the carbon and nitrogen metabolic processes of kidney bean leaves,it provides a theoretical basis for the application of humic acid fertilizer for kidney beans in Northeast China.This trial was conducted at the Anda Experimental Base of Bayi Agricultural Reclamation University in Heilongjiang,using the kidney bean variety Baisak as the test material for two years of field trials in 2021 and 2022.There were six treatments:CF(conventional fertilizer application),RF(fertilizer reduction of 20%),RFH1(fertilizer reduction of 20%+45.0 kg/ha humic acid bio-fertilizer),RFH2(fertilizer reduction of 20%+67.5 kg/ha humic acid bio-fertilizer),RFH3(fertilizer reduction of 20%+90.0 kg/ha humic acid bio-fertilizer),RFH4(fertilizer reduction of 20%+112.5 kg/ha humic acid bio-fertilizer).The experiment was conducted to determine the indicators of carbon and nitrogen metabolism and their products throughout the reproductive period of kidney bean,and to determine the yield of kidney bean and its constituent factors at the harvesting stage.The activities of sucrose synthase(SS),sucrose phosphate synthase(SPS),acidic invertase(AI),neutral invertase(NI)in carbon metabolism and nitrate reductase(NR),nitrite reductase(NiR),glutamate synthase(GOGAT)and glutamine synthetase(GS)in nitrogen metabolism were analyzed by fertilizer reduction with humic acid bio-fertilizer,and the activities of carbon and nitrogen metabolites sucrose,soluble sugar,starch and soluble protein.To determine the effect of humic acid on the carbon and nitrogen metabolism of kidney bean.The results showed that the application of humic acid bio-fertilizer increased the activity of enzymes related to carbon and nitrogen metabolism in kidney bean leaves,increased the content of carbon and nitrogen metabolites and improved the yield of kidney bean compared with CF treatment.During the reproductive period,SS activity of RFH2 treatment was significantly increased by 9.5%—15.8% compared to CF treatment.RFH3 treatment significantly increased the SPS activity by 16.5%—38.1% compared to CF treatment.The AI activity of RFH3 treatment was significantly increased by 10.8%—25.5% compared to CF treatment.RFH2 treatment increased NI activity by 14.0%—32.1%.With the application of humic acid bio-fertilizer,NR and NiR activities were significantly increased by 22.6%—50.1% and 16.3%—19.8%,and GOGAT activities were significantly increased by 16.0%—35.7% in the RFH2 treatment compared to the CF treatment.RFH3 treatment significantly increased the GS activity by 14.5%—44.1% compared to CF treatment.Meanwhile,among the treatments with humic acid bio-fertilizer,RFH2 treatment significantly increased the carbon and nitrogen metabolites sucrose,soluble sugar,starch and soluble protein in kidney bean leaves by 7.6%—9.3%,14.1%—26.8%,6.7%—10.5% and 3.7%—8.8%,respectively and the starch content significanthy increased by 0.8—1.3 percentage points.In addition,the application of humic acid bio-fertilizer was able to increase the yield of kidney bean,with a significant increase of 24.8%(2021)and 21.5%(2022)in the RFH2 treatment compared to the CF treatment.The treatment of 20% reduction in conventional chemical fertilizer application with 67.5 kg/ha of humic acid bio-fertilizer(RFH2)could increase the activity of enzymes related to carbon and nitrogen metabolism in kidney bean leaves,increase the accumulation of carbon and nitrogen metabolites in leaves,and increase the yield of kidney bean.

Ideal plant architecture can significantly improve crop yield,but the relationship between plant architecture traits and yield traits is still unclear in foxtail millet.To provide a theoretical basis and germplasm resource for plant architecture breeding in foxtail millet,10 plant architectures traits(plant height,main stem length,panicle length,panicle neck length,panicle diameter,tiller number,node number,length of flag leaf,width of flag leaf and area of flag leaf)and 3 yield traits(panicle weight,panicle grain weight and 1000-grain weight)were analyzed via 126 F₆ recombinant inbred lines(RIL)from a F₁ arrived from a cross between Aininghuang and Jingu 21 under three ecological environment consisting of Changzhi,Yuci and Datong.Based on the best linear unbiased estimation(BLUE),variance analysis,correlation analysis,partial correlation analysis,principal component analysis,multiple regression analysis and cluster analysis were conducted.The phenotype variation analysis showed there were an extremely significant difference between plant height and main stem length in three ecological environments,a significantly or extremely significant difference between panicle neck length and node number in two ecological environments,and the significant or extremely significant differences among panicle length,panicle diameter,panicle weight,panicle grain weight and tiller number in single ecological environment.In RIL population, an abundant variation was observed for 13 traits with the approximately normal frequency distribution,and the variation coefficients ranged from 6.86% to 31.71%.Except for the main stem length in Yuci, other traits showed a transgressive separation in three ecological environments.Correlation analysis and partial correlation analysis indicated that panicle weight and panicle grain weight were extremely significant positive correlated with plant height,main stem length,panicle length,panicle neck length and node number,while they were extremely significant negative correlated with tiller number,panicle weight was significantly positive correlated with flag leaf length.Principal component analysis simplified 13 traits into 4 principal components,and the cumulative contribution rate was up to 93.938%.The fitting degree R² of multiple regression analysis was 0.614, and main stem length,panicle length and tiller number were the main factors affecting panicle weight.The RIL population was divided into 7 groups via cluster analysis,among which Group Ⅴ consisted of 3 materials with the highest yield, medium plant height and good comprehensive traits,which could be used as elite parents for ideal plant architecture breeding.

In order to alleviate continuous cropping obstacles and improve soil, to ensure sorghum raw grain production and sustainable agricultural development. The long-term located experiment of continuous cropping sorghum was carried out in Dongbai base of Sorghum Research Institute of Shanxi Agricultural University from 2019 to 2020 to study the effects of tillage methods(traditional tillage,no tillage,rotary in autumn,subsoiling in autumn,deep ploughing in autumn,deep ploughing in spring)in fallow period on soil moisture,organic carbon content and yield of continuous cropping sorghum,aiming to find the suitable tillage method and time for increasing the yield of continuous cropping sorghum,and the mechanism of water conservation,carbon sequestration and yield increase so as to provide cultivation techniques and theoretical basis for the stable production of sorghum.The results showed that tillage in fallow period increased the soil organic matter in 0-20 cm soil layer in each growth period of sorghum,and increased the content of particulate organic carbon,light fraction organic carbon,heavy fraction organic carbon,readily oxidized organic carbon and dissolved organic carbon, and also increased soil water storage in 0-100 cm soil layer by 0.72-46.52 mm before sowing and soil water storage of 0-100 cm soil layer at each growth period, furthermore, the soil water before sowing continued to be used until jointing stage and it still was very effective even though much precipitation in the middle and late stages.Meanwhile,tillage in fallow period increased the yield by 4.75%-23.67% and the water use efficiency in the growth period by 19.09-29.19 kg/(ha·mm),especially the increased effect of deep ploughing in autumn was more significant.The correlation analysis showed that the yield of continuous cropping sorghum was significantly positively correlated with soil moisture and organic matter content,and the yield was more closely related to the soil moisture in the early growth stage if the base soil moisture level was higher and more closely related to the soil moisture in the middle and late stages if the base soil moisture level was lower and the precipitation in the middle and late stages was more.In short,deep ploughing in autumn of continuous cropping sorghum during fallow period was beneficial to increase the organic carbon content and promote the soil moisture conservation so that the moisture continued to be used at jointing stage,thereby increased yield and water use efficiency.

Tiller higher than main stem is one of the important reasons that make the uniformity of sorghum varieties and mechanized production of sorghum complicated.In order to clarify the mechanism of the gene that regulates the tiller height in sorghum,improve the uniformity of sorghum varieties and breed sorghum varieties suitable for mechanized production,based on the mapping results of our previous studies,15 of the sorghum variety whose tiller height was consistent with main stem height as well as 17 of the sorghum variety whose tiller height was higher than main stem height,were selected to form the natural population to have the candidate genes tested.It was found that it was the SNP3 locus belonging to the gene Sobic.009G2133001.v3.2 located in the conserved domains of Hydrolase_4 affects the tiller height,it was named SbTH.With two sorghum varieties K35-Y5 and 1383 taken as material,the expression patterns of gene SbTH in different sorghum tissues were analyzed by Real-time fluorescence quantitative PCR.The results showed that the SbTH gene got expressed in both the roots and the leaves.Though the expression levels were different,the trends were basically the same.In the stem of variety 1383 whose tiller was higher than main stem,the expression level and trend were almost the same.Only in variety K35-Y5 whose tiller height was consistent with main stem height,at anthesis of main stem,reverse expression pattern was observed.While the expression level of main stem reached the maximum,the expression level of tiller was lowered to the minimum.From above results,we concluded that the expression level of SbTH was low in the tiller of K35-Y5,thus the overgrowth of the tiller internodes got controlled,forming the plant phenotype whose stem and tiller had the same height.The expression level of SbTH was high in the tiller of variety 1383,thus the growth of tiller internodes was promoted,which made the tiller be higher than the stem.Therefore,it is believed that the differential expression of gene SbTH at anthesis of main stem is the key to tiller height regulation.

WRKY transcription factors act important regulators in plant response to low phosphorus.Buckwheat performs well in under-fertilized soils with higher phosphorus use efficiency.Taking tartary buckwheat as experimental materials,this study aims to explore the possible regulatory roles of WRKY genes in phosphorus starvation response of buckwheat.The entire coding sequence(CDS)of FtWRKY6 gene was cloned from RNA samples generated from roots treated by low phosphorus using reverse transcription PCR.The obtained CDS of FtWRKY6 was 1 572 bp in length,encoded a polypeptide of 524 amino acid residues which consists of two conserved WRKY domain each with a zinc finger motif of CCHH,and belonged to the WRKY group Ⅰ.FtWRKY6 shared the highest identity(55.5%)at the amino acid level with Camellia sinensis CsWRKY24.Transient expression assay in protoplasts showed that FtWRKY6 protein was localized in nucleus.Yeast one-hybrid assay revealed that FtWRKY6 had transcription-activating activity.Real-time fluorescence quantitative PCR analysis showed that the expression of FtWRKY6 in roots was significantly induced by low phosphorus and three related hormones such as indole acetic acid(IAA),gibberellin(GA)and cytokinin(CTK).Taken together,FtWRKY6 possesses basic structural and biochemical characteristics as a putative transcription factor,and may be involved in low phosphorus response in roots possibly by crosstalk of IAA,GA and CTK signaling pathways.

In order to preliminarily identify the function of HvMUTE, a transcription factor gene for stomatal development in barley, and by analyzing its biological characteristics and expression patterns, HvMUTE, a transcription factor gene for stomatal development in barley, was studied by bioinformatics analysis, PCR amplification and qRT-PCR. Because barley G1614 is the sister line of barley MOREX, and the reference genome data of barley MOREX has been published. So HvMUTE gene sequence was obtained by homology Blast of BdMUTE against between the referencre genome of barely G1614. The coding region of the HvMUTE gene with 651 bp in length was isolated from the first leaf emerging from the bud of barley G1614. Bioinformatics analysis indicated that HvMUTE protein was an unstable protein with no obvious hydrophilicity and hydrophobicity, located in the nucleus, and hold a Helix-Loop-Helix (HLH) structure in three demision level. Phylogenetic tree analysis showed that HvMUTE was closely related to MUTEs of wheat and Aegilops. qRT-PCR results showed that there was no significant change in the expression of HvMUTE gene under drought conditions. This result was different from previous studies, and it was speculated that barley was a monocotyledonous plant, and the existence of parathyroid cells in the stomatal structure was different from that of dicotyledonous plants.

In order to elucidate the effect of decreasing nitrogen rate and increasing planting density on photosynthesis,dry matter accumulation and transportation characteristics and yield of sorghum,a field experiment was conducted using the waxy sorghum hybrid Jinyunuo 3 as experimental material in 2017-2018.Four treatments of normal nitrogen application with normal planting density(CK),normal nitrogen application with dense planting density(T1),reducing nitrogen application with normal planting density(T2),and reducing nitrogen application with dense planting density(T3)were set to investigate the chlorophyll content(SPAD)and leaf area index(LAI)at heading stage,dry matter accumulation and transport characteristics,yield and yield components of sorghum. The results showed that,compared with CK,the SPAD of the top three leaves at heading stage and LAI were decreased by reducing nitrogen application,while the SPAD was decreased by dense planting,but LAI was increased significantly.The dry matter accumulation of sorghum population increased with the development of growth process and increased rapidly after jointing stage and reached the maximum in maturity stage.Reducing nitrogen application improved dry matter translocation efficiency of leaf and stem+sheath before anthesis and contribution to grain,but decreased dry matter accumulation of population,dry matter accumulation after anthesis and its contribution to grain.Increasing density significantly boosted dry matter accumulation of population,dry matter translocation of leaf and stem+sheath before anthesis,as well as their transportation efficiency and contribution to grain,but reduced the contribution of dry matter to grain after anthesis. The ear weight and 1000-grain weight were reduced by dense planting,but the yield increased significantly. The ear weight and 1000-grain weight were decreased by reducing nitrogen application,but the yield of normal density decreased while that of densification increased significantly. Compared with CK,the 2-year average yield of T1 and T3 treatments were significantly higher by 8.43% and 7.92% respectively,and there was no significant difference between the two treatments. In conclusion,the planting mode of Jinyunuo 3 in Chongqing was reducing nitrogen application with dense planting,that was,applying nitrogen 150 kg/ha and density 12.75×10⁸ plants/ha. It was beneficial to realize high yield,high efficiency and nitrogen saving cultivation of sorghum.

In order to explore the changes of physiological characteristics and genetic materials of naked oats during storage, the germination rate, germination potential, malondialdehyde(MDA)content, peroxidase dismutase(SOD)activity, catalase(CAT)activity, peroxidase(POD)activity and polyphenol oxidase(PPO)activity of naked oats seeds with different storage years were measured. The number of cells with genetic material distortion was counted by microscopic examination.The results showed that the germination rate and germination potential of naked oats seeds decreased with the extension of storage years.After storage for 8 years,Bayou 1 decreased by 86.42 and 96.92 percentage points;the content of MDA in naked oats seeds increased with the extension of storage years,and the maximum increase of Jinyan 8 was 5.68 times;the activities of SOD,CAT,POD and PPO of naked oats seeds decreased with the extension of storage years.After 8 years of storage,Bayou 1 decreased the most,which were 84.66%,74.38%,54.09% and 81.44% respectively;the number of cells with genetic material distortion in naked oats increased with the extension of storage years,and the average increase of the three varieties for 8 years was 11.87 times.The germination rate was significantly correlated with MDA content,SOD activity,CAT activity,POD activity,PPO activity and the number of aberrant cells(P<0.01),and the number of aberrant cells was significantly correlated with MDA content,SOD activity,CAT activity,POD activity and PPO activity(P<0.01).Bayou 1 had the best storage resistance,Jinyan 17 was the second,and Jinyan 8 was the worst.The germination rate and germination potential of naked oats decreased with the extension of storage years,the activities of SOD,CAT,POD and PPO decreased with the extension of storage years,and the content of MDA and the number of distorted cells increased with the extension of storage years;SOD,CAT and POD activities are essential enzymes for seed survival,but not the key enzymes for seed germination.

In order to establish a chlorate-based screening system for barley with different nitrogen use efficiency(NUE),the effects of chlorate treatment on barley seedlings were explored,barley germplasms with different responses to chlorate treatment will be used for molecular mechanism research on NUE and crop breeding with high NUE in barley.Eighteen barley landraces from Shanghai region and three main cultivars in present barley production were used as test materials,and hydroponic experiments were carried out in an artificial climate room,and 2 mmol/L KNO₃(CK)and 2 mmol/L KClO₃ treatments were setrespectively.The traits of seedling height,root length,shoot and root dry masses of barley seedlings were measured after 4 days of treatments,respectively.It was showed that the growth of barley seedlings was obviously inhibited under chlorate treatment,especially the seedling height and dry mass related traits.The ANOVA showed that there were extremely significant differences in all traits under both chlorate treatment and normal condition(the control),and there were also extremely significant interactions between the treatments and varieties.The coefficient of variation analysis showed that the coefficients of variation of root length and dry mass related traits were relatively large in both treatments,while the seedling height was relatively small.Correlation analysis also showed that these indexes were positively correlated under both conditions.The chlorate susceptibility was consistent based on both seedling height and shoot dry mass in general,but there were still some differences.The response of seedling height and shoot dry mass to chlorate could be used as an index for screening barley with different NUE,and B104,B002,B053,B092 and B068 were among the six most sensitive varieties to chlorate based on both seedling height and shoot dry mass,indicating that these five barley cultivars might have higher NUE;while B016,B006 and B008 were among the 6 least sensitive varieties to chlorate,suggesting that the NUE of these three barley varieties might be relatively lower.

In order to determine the effects of V.villosa Roth cultivation in apple orchard on soil microbial community structure,the high-throughput sequencing technology was used to analyze the microbial structure of V.villosa Roth cultivation soil in seven areas of Shandong Province and different phenological period of the same orchard,taking natural grass treatment as comparison.The correlation between microbial community structure and physicochemical properties of grass cultivation soil was analyzed.Results showed that,in seven sampled sites of Shandong Province,the relative abundances of Metarhizium in V.villosa Roth cultivation treatment were all higher than those in the control,and the difference was biggest in Dongying Area.The relative abundances of Fusariumin V.villosa Roth cultivation treatment of six sites were lower than those of the control,except for Zoucheng.The relative abundances of Gibberella in V.villosa Roth cultivation treatment of six sites were lower than those in the control,except for Rongcheng.In Zoucheng and Longkou,the relative abundances of Alternaria were lower than those of the control.Analysis of microbial community structure in different apple phenological stages of V.villosa Roth cultivation in the same orchard showed that,the relative abundance of Aspergillus in flowering stage soil was much lower than that of natural grass.The relative abundances of Fusarium and Aspergillus in fruit setting stage in V.villosa Roth cultivation treatment were lower than those of natural grass.The relative abundance of Bacillus in V.villosa Roth treatment was higher in fruit expansion stage.The relative abundance of Bradyrhizobium was higher in mature stage,while Gibberella,Cladosporium and Bipolaris were much lower than those of natural grass.Effects of V.villosa Roth cultivation in apple orchard on soil microbial community structure differed in different region and phenological stage.However,the relative abundance of beneficial bacteria in soil was increased,while that of pathogenic fungi was decreased,which was helpful to improve orchard soil micro-ecological environment and promote the healthy cultivation of fruit trees.

In order to clarify the characteristics of the endophytic bacterial community of different varieties of foxtail millet,reveal the key species related to foxtail millet downy mildew resistance.DNA extraction was performed on the lowest node stem and the highest node stem tissues of 3 kinds of foxtail millet downy mildew-resistant and 3 kinds of foxtail millet downy mildew-susceptible foxtail millet plants.We used Illumina Miseq to sequence the bacterial 16S rDNA of the samples and analyzed the susceptible community composition of endophytic bacteria.The results showed that at each classification level,the endophytic bacterial species from the lowest node stem to the highest node stem showed two different trends in disease-resistant and susceptible foxtail millet samples,which were basically stable and significantly decreased.And the species composition of the endophytic bacterial community in disease-resistant foxtail millet was more abundant than that of susceptible foxtail millet.19 important endophytic bacteria phyla were obtained:(from the comparison of the endophytic bacteria ubiquitous in the lowest node stem of disease-resistant and susceptible foxtail millet samples were obtained) 2 species of endophytic bacteria phyla specific to disease-resistant foxtail millet;(from the comparison of all endophytic bacteria of disease-resistant and susceptible foxtail millet samples 16 species of endophytic bacteria phyla unique to disease-resistant foxtail millet and 2 dominant groups with relatively large abundance of disease-resistant foxtail millet were obtained).It can be seen that the endophytic bacterial communities in different foxtail millet varieties and different parts are different,and the endophytic bacterial species of disease resistance are more abundant than that of susceptible foxtail millet.Among them,the endophytic bacteria phyla unique to disease-resistant foxtail millet materials and the dominant endophytic bacteria phyla with relatively large abundance may have an effect on the prevention and treatment of foxtail millet downy mildew,which is worthy of further study.

In order to understand the function of SibHLH19 in foxtail millet,the CDS sequence and promoter sequence of SibHLH19 gene were separately cloned with the leaf cDNA and genomic DNA from resistance material Shilixiang as template by PCR.Promoter cis-acting elements and biological characteristics were analyzed using bioinformatics online tools.Then the expression patterns of SibHLH19 in different tissues and during the process to rust resistance were surveyed by qRT-PCR,respectively.Lastly the prokaryotic expression characteristics for the gene were detected by SDS-PAGE,laying a theoretical foundation for further research on SibHLH19 gene function and disease resistance mechanism.The results showed that the CDS sequence of the SibHLH19 transcription factor was 843 bp in length,encoding a total of 280 amino acids,the predicted protein molecular weight was 29.97 ku.The theoretical isoelectric point was 5.85,and the encoded protein chemical formula was C₁₂₉₆H₂₀₇₁N₃₉₇O₄₀₀S₁₁,containing a bHLH conserved domain,belonging unstable hydrophilic protein.The largest element of the protein's secondary structure was random coils,and the smallest element was a β-turn.Evolutionary analysis showed that SibHLH19 had the higher homology to the amino acid sequences of Panicum miliaceum (RLM85279.1),Panicum hallii (PUZ71581.1)and Panicum virgatum (XP_039835205.1),and had the lowest homology with Triticum aestivum(KAF7059972.1)and Aegilops tauschii subsp.strangulata (XP_040244423.1).The analysis of the promoter cis-acting elements showed that there were multiple response elements such as hormones and stresses in the promoter region of the SibHLH19 gene.Tissue expression analysis showed that the gene was mainly expressed at the seedling stage with the highest expression in the aboveground part,and was almost no expression at the booting stage.Within 24 hours of the response to the biotic stress of rust disease in foxtail millet,the SibHLH19 gene expression was up-regulated at 8 and 16 h in the disease resistance response,while its expression was only slightly up-regulated at 16 h and down-regulated at the rest of the time points in the susceptible response.It was speculated that SibHLH19 played a positive regulatory role in the resistance response to rust disease in foxtail millet.The constructed prokaryotic expression vector pET30a-SibHLH19 could express the SibHLH19 fusion protein with an apparent molecular weight of about 44 ku after being induced by 0.1 mmol/L IPTG.

In order to explore the effective methods for the identification of drought tolerance of foxtail millet during the entire growth period,select the identification indices of drought tolerance of foxtail millet,and speed up the process of drought tolerance breeding of foxtail millet,a field experiment was conducted using a randomized incomplete block design(alpha-lattice design)and repeated thrice in 2019—2020. Each experiment consisted of 30 foxtail millet genotypes treated under drought stress(DS)and normal water supply(CK). The agronomic traits and drought tolerance coefficient(DC)of the genotypes were assessed during the entire growth period. Combined analysis of variance showed that soil water environment had significant effects on 1000-grain weight,and extremely significant effects on the other indices. Genotype had significant effects on spike weight and grain weight per plant,and extremely significant effects on the other indices. Besides,the interaction between genotype and soil water environment extremely significantly affected the growth traits of foxtail millet,but not yield traits(except 1000-grain weight). Under drought stress,the characteristic value of each index decreased in varying degrees compared with CK,and the sensitivity of each index to drought stress was different. The results of t test showed that the effect of drought stress was significant(except 1000-grain weight). GGE biplot explained 71.15% of the total variation of data.The drought tolerance coefficient of each index was correlated in different degrees,in which the drought tolerance coefficients of plant height,spike length,stem and leaf dry weight and top second leaf area were significant positive correlation,and that of spike weight per plant,grain weight per plant,kernels per spike and yield were also significant positive correlation. The drought tolerance of foxtail millet could be reflected by different agronomic traits. According to the distance from ideal drought-tolerant varieties and ideal drought-tolerant evaluation indices,the drought tolerance and evaluation indices of foxtail millet materials were ranked. Taixuan 26,Chaogu 62,Chaogu 13 and other materials had strong drought resistance,plant height and spike weight per plant could be used as indices for drought tolerance identification in foxtail millet. GGE biplot provided an objective and effective new visual identification method for the breeding of drought resistant foxtail millet varieties.

In order to reveal the diversity characteristics of endophytes in different species and different organs,the correlation between endophyte community structure and host species and organ types was preliminarily clarified.The stems,leaves and leaf sheaths,which were respectively collected from the plants of the foxtail millet blast-susceptible varieties Shawan millet and Jigu 22 and the foxtail millet blast resistant varieties Xiaoqinggu and Shiliuzi,were used to carry out the endophytic diversity by high-throughput sequencing based on the 16S rDNA V3—V4 region.There were certain differences in endophyte species composition between susceptible and resistant varieties.In all tested samples,the dominant groups at the phylum level were Proteobacteria and Actinobacteriota.Bacteroidota,Chloroflexi,Myxococcota,Firmicutes followed.Alpha diversity analysis showed that the susceptible varieties(Shawan millet,Jigu 22)had higher abundance of endophyte in leaves.PCoA analysis revealed that the organ type had a greater impact on the endophyte community structure than the variety.Species composition analysis showed that the susceptible varieties Shawan millet and Jigu 22 contained endophytic flora that were significantly different from those of Xiaoqinggu and pomegranate(resistant to foxtail millet blast).The susceptible varieties(Shawan millet,Jigu 22)contained Entotheonellaeota phylum in leaves,while resistant varieties had Hydrogenedentes phylum in leaf sheaths.It clarified that the diversity and community structure of endophytes in different organs and millet varieties susceptible and resistant to foxtail millet blast were different,and organ types had a greater impact on the community structure of endophytes than varieties.

The SiPRR73 gene was cloned from Yangu 11 using RT-PCR technology,and through analyzing tissue-specific expression,responsive features of SiPRR73 to different photoperiods,photo-thermal combinational treatments and five abiotic stress treatments,the regulation mode of photoperiod and temperature on SiPRR73,and the responsive pattern of SiPRR73 to abiotic stresses in foxtail millet were explored. The results showed that totally 2 928 bp cDNA sequence of SiPRR73 was obtained from Yangu 11,which included 2 283 bp CDS region,encoding 760 amino acids. The SiPRR73 proteins of C4 crops including Panicum miliaceum,Panicum hallii,Sorghum bicolor and Zea mays showed relatively close relationship with SiPRR73. The second parietal leaf was the highest expression tissue of SiPRR73,but the expression level at root,stem and panicle tissues was relatively lower. The expression level of SiPRR73 was higher at light period than that at dark period under both short-day and long-day conditions,and during the whole vegetative growth phase,SiPRR73 showed higher expression level under long-day compared to short-day,which indicated that the expression of SiPRR73 was induced by light and controlled by photoperiod. The temperature determined expression peak number of SiPRR73 and the photoperiod determined occurrence time of expression peaks,so temperature and photoperiod participated in regulating of SiPRR73 expression mutually. PEG and low temperature stresses induced SiPRR73 expression totally,NaCl induced SiPRR73 expression at early stress stage,but inhibited it at later stress stage. Fe stress inhibited SiPRR73 expression at early stage,but induced it at later stage. ABA stress caused the close responsive feature of SiPRR73 to NaCl. This study indicated that SiPRR73 showed light-dependent expression feature,and photoperiod and temperature regulated SiPRR73 by interaction pattern,suggesting that SiPRR73 participated in adaptability regulation process to different photo-thermal conditions and might play a certain role in coping with drought,low temperature,ABA,NaCl and Fe stresses in foxtail millet.

In order to alleviate the continuous cropping obstacle of millet,provide a reference for optimizing millet planting mode,millet continuous cropping(Si)was named as control(CK),millet-corn(Si-Zm),millet-potato-corn(Si-St-Zm),millet-corn-soybean(Si-Zm-Gm)and millet-soybean-potato(Si-Gm-St)were used to analyze the effects of different rotation patterns on the physiological indicators,photosynthetic characteristics,agronomic characters,yield and downy mildew incidence rate during the critical millet growth periods.The results showed that compared with CK,in the Si-St-Zm,Si-Zm-Gm and Si-Gm-St rotation patterns,the activeness of superoxide dismutase,peroxidase and polyphenol oxidase in millet flag leaves were significantly increased,with the largest increases of 45.55%,41.55% and 109.09%,respectively.In the Si-Zm-Gm and Si-Gm-St rotation patterns,millet plant height,stem thickness,root length and root branch number were significantly increased,with the largest increases of 30.48%,30.50%,31.76% and 13.79%, respectively.In addition,compared with CK,under the Si-Gm-St rotation system,the H₂O₂ and MDA content in the millet flag leaves were significantly decreased,with the maximum reductions of 18.78% and 47.29%, respectively;and the stomatal conductance,net photosynthetic rate,transpiration rate and relative chlorophyll content were significantly improved by 31.94%-101.43%,35.74%-234.00%,16.44%-46.97% and 24.15%-66.16%,respectively;with millet ear length,1000-grain weight and yield increased by 14.90%,17.09% and 10.58%,respectively;and millet downy mildew incidence rate significantly reduced by 12.33%.In short,compared with CK,the Si-Gm-St rotation system significantly increased the activeness of SOD,POD and PPO,and improved photosynthetic efficiency in millet flag leaves,meanwhile,the millet yield and disease resistance enhanced.Therefore,compared with Si-Zm,Si-St-Zm and Si-Zm-Gm rotation patterns,Si-Gm-St rotation system has the best effect on alleviating continuous cropping obstacles,which can provide a reference for optimizing millet planting system.

In order to explore the relationship between soluble sugar content and grain starch content of spring barley,Mengpi 3 and Mengpi 5 were used as test materials,and four density treatments of 3.75,4.50,5.25,6.00 million plants/ha were set.The dynamic changes of soluble sugar and starch content in leaves,stems and grains during grain filling of barley under different planting densities were studied from 2018 to 2019.Its effect on the formation of grain starch components was analyzed.The results showed that the soluble sugar content in leaves,stems and grains of 2 years and 2 varieties showed a unimodal curve with the grain filling process,and the peak value appeared on 21 days after anthesis.With the increase of planting density,the soluble sugar content in leaves,stems and grains was increased first and then decreased,with the increase of planting density,and the peak value was 5.25 million plants/ha treatment.The contents of total starch,amylose and amylopectin in grains of 2 varieties in 2 years increased gradually with the filling process,increased first and then decreased with the increase of planting density,and the peak value was 5.25 million plants/ha treatment.Correlation analysis showed that there was a very significant positive correlation between the soluble sugar content of leaves,stems and grains at each filling stage and the starch component content of grains at maturity;the path analysis showed that the soluble sugar content of leaves,stems and grains at 21 days.After anthesis had the greatest effect on the total starch content of grains at maturity,and the path coefficients reached 1.002 3,0.580 4 and 0.745 5,respectively.The soluble sugar contents of leaves,stems and grains at 35 days after anthesis and 7 days after anthesis were the most affected on amylose content,and the path coefficients were 0.776 6,0.469 7 and 0.715 6,respectively.The soluble sugar content of leaves at 21 days after anthesis,stems at 7 days after anthesis and grains at 14 days after anthesis had the greatest effect on the amylopectin content of grains at maturity.The path coefficients were 1.046 9,0.638 2 and 0.775 6,respectively.5.25 million plants/ha was the most suitable planting density to increase the content of starch components in barley grains.The soluble sugar content of stem and grain at the beginning of grain filling 7 d after anthesis is of great significance to improve the yield and quality of barley.

To study the decomposition characteristics of sorghum and maize residues and the functional diversity of microbial community in straw decomposition,under different residual types(sorghum stalk-leaves,maize stalk-leaves,sorghum root,maize root),soil type(cinnamon soil,yellow loam soil),nitrogen treatment(adjust C/N ratio,not adjusted),the culture experiment method was used to explore the decomposition characteristics of residues under different decomposition conditions,and to analyse the metabolic functional diversity of microbial community used the BIOLOG-ECO plates method in straw decomposition process.The results showed that the decomposition rate of sorghum and maize residues was faster in the early stage than the late stage.The residual dry matter degradation rate and CO₂ release rate had the following pattern of decomposition rate was shown,sorghum stalk-leaves>maize stalk-leaves>sorghum root>maize root,under the same soil and nitrogen treatment.According to the second experiment, the dry matter degradation rates of sorghum stalk-leaves and maize stalk-leaves were 55.50% and 48.00%,respectively,however,the dry matter degradation rate of sorghum root and maize root were 31.25% and 16.75%,respectively at 60 d of incubation,under the condition of cinnamon soil+N treatment.The degradation rate of hemicellulose and cellulose in root were lower than that in stalk-leaves,under the same soil and N treatment conditions,the decomposition of hemicelluloses and cellulose was decreased by 23.70,18.80 percentage point,in sorghum root treatment than sorghum stalk-leaves treatment at 90 d of incubation,under the condition of cinnamon soil+N treatment.The microbial metabolic activity of straw was the highest at 30 d and lowest at 90 d during decomposition.The metabolizable ability of microbial community of straw decomposition to amines and phenolic acids was lower on the 1st day of decomposition,and the metabolizable ability to carbohydrates,amino acids and polymers was significantly decreased on the 90th day,compared with 30 d.Collectively,the decomposition of sorghum residues was easier than maize,and adjusting C/N ratio could accelerate the decomposition of residue to a certain extent.The microbial metabolic diversity was the highest at 30 d under the experimental conditions.

To ascertain effects of sowing dates on the yield and quality of both forage and grain among different barley varieties, four sowing dates(factor A)were imposed on four six-row barley varieties(factor B)to compare the differences of yield and quality of tillering forage and mature grain. The results showed sowing dates had a greater impact on forage yield and less impact on grain yield. Early sowing accelerated cutting times and raised forage yield while the highest forage fresh weight(12.44 t/ha)and dry weight(1.49 t/ha)were obtained at sowing date A1(September 30). Significant differences were identified among varieties for both forage and grain yield. Variety B2(Wansipi 14008)achieved the highest forage fresh weight of 10.51 t/ha and dry weight of 1.38 t/ha, and the second highest grain yield of 1.82 t/ha. Variety B1(Yangsimai No.1)achieved the highest grain yield of 3.58 t/ha and the second highest forage fresh weight of 9.00 t/ha and dry weight of 1.17 t/ha. Thus variety B1 and B2 can be used for harvest of both forage and grain. Sowing dates had a greater effect on forage quality but less effect on grain quality. Forage quality traits excluding acid detergent lignin content varied significantly among sowing dates of which A2 and A4 had greater values for corresponding traits. No significant differences were found among varieties for forage quality traits, which can be used as elite forage crops. Differences of grain quality were significant among varieties of which B2 had the highest protein content and B1 had the highest starch content, implying selection of varieties can improve feed quality. Interaction of sowing dates and varieties had a certain effect on forage yield but little effect on other traits. Based on the above analyses, Wansipi 14008 and Yangsimai No.1 can be used and sowed on September 30 to achieve harvest of both elite forage and grain.

In order to clarify the difference of yield and nitrogen use efficiency between new and old generations of waxy sorghum varieties(lines)in Guizhou, the sorghum cultivars of HYZ, QG8H, HongKN and HeiKN were used as experimental materials, two nitrogen treatments(LN and HN)were set up.The differenceof yield, nitrogen accumulation and nitrogen use characteristics of which were analyzed by split plot design. The results showed that:the yield, dry matter and nitrogen accumulation of 2010s cultivars(HYZ and QG8H)were significantly increased by 25.4%, 25.1% and 33.3%, respectively, compared with those of 1990s cultivars(HeiKN and HongKN). NHI under LN treatment was significantly different among cultivars, but not under HN treatment. Compared with LN, RNAP of 1990s cultivars decreased significantly under HN treatment, with a range of 20.9%, which indicated that the 2010s cultivar had a stronger post-flowering N assimilation capacity, and a stronger grain N accumulation capacity at both low and high N levels.NPFP, NARR, NRE and NFAE of 2010s cultivars were increased by 13.9 kg/kg, 0.7 kg/kg, 20.3% and 4.1 kg/kg, respectively, compared with the 1990s cultivars. Yield, DMA, TNA were significantly positively correlated with NRE, which indicated that the increased yield of waxy sorghum in Guizhou Province might relate to the increase of nitrogen accumulation caused by the improvement of NRE, which provided sufficient nitrogen supply for the normal physiological metabolism of waxy sorghum.

In order to further reveal the role of kidney common bean NAC gene in regulating plant growth and development and in response to abiotic stress, this research was used the salt-tolerant common bean variety HYD as the test material and used the Illumina HiSeq technology, the transcriptome of common bean leaf tissue under the NaHCO₃ and NaCl treatments was constructed. A total of 8 saline-alkaline related NAC transcription factors were screened from the transcriptomic data, and carried out analysis of physicochemical property, systematic evolution, phosphorylation site prediction, protein secondary structure prediction, promoter element analysis, gene structure analysis, chromosomal location analysis and expression analysis. The result showed:The molecular weight of 8 common bean saline-alkaline response NAC genes was 23 676.36-44 354.33 ku, and the protein codes were 203-394 amino acids. The isoelectric point was between 4.74 and 8.86, of which 3 genes encoded acidic proteins, and 8 genes were divided into 4 subfamilies (a-d), positioning in 8 chromosomes, including 3 membrane-bound proteins, the number of serine was the largest in 8 proteins, there were 10-22, and the random coil structure accounts for the largest proportion, 68.0% to 84.5%. All 8 proteins were located in the nucleus. Under NaHCO₃ treatment, 4 genes were up-regulated expression (log₂FC>2), 2 genes were down-regulated expression (log₂FC<-2), Under NaCl treatment, 1 gene was up-regulated expression (log₂FC>2), 4 genes were down-regulated expression (log₂FC<-2), 3 genes respond to both NaHCO₃ and NaCl. A total of 10 promoter elements were found in 8 gene promoters, and each gene contained 3-7 elements. It indicated that these genes might be involved in the stress response of common beans.

In order to reveal the possible functional effects of SiCCT gene, and provide foundation for further research of the function of SiCCT gene in photo-thermal interaction-controlled flowering process of foxtail millet, the photoperiod sensitive millet variety Huangmaogu was used as experimental material to analyze the diurnal expression patterns of SiCCT gene under long-day and high temperature(LD, 27℃), long-day and low temperature(LD, 22℃), short-day and high temperature(SD, 27℃), short-day and low temperature(SD, 22℃), totally four photo-thermal combinational conditions by fluorescence quantitative PCR. Furthermore, based on the survey data of ten main agronomic traits for two consecutive years, candidate gene-based association analysis was performed. The results showed that the expression of SiCCT gene was not affected by temperature, and the expression level of SiCCT gene under long-day was wholly higher than that under short-day at light period. While at darkness period, the expression of SiCCT gene was affected by temperature, especially under short-day, the expression level of SiCCT gene at low temperature was obviously higher than that at high temperature. Based on the association analysis of candidate gene, it was found that 11 polymorphic loci detected in SiCCT gene were significantly associated with 8 major agronomic traits(P <0.05), among which, SNP-10 was associated with heading stage, leaf number and grain weight per panicle at Luoyang, Henan and Jilin, Jilin, SNP-100 and SNP-104 were associated with plant height, leaf number and panicle length at Luoyang. SNP-51 was detected at Ledong of Hainan, Luoyang and Jilin for two consecutive years, but the related traits were different, which were ear diameter, branch number per panicle and leaf number at Ledong, Luoyang and Jilin, respectively.The expression of SiCCT gene was controlled by photoperiod, and temperature also affected its expression at darkness period under short-day. SiCCT gene possessed pleiotropic effects, but its function was regulated by photoperiod condition.

In order to study the tolerance of heterologously overexpressed Atvip1 gene in sorghum to defense saline-alkali stress and the corresponding growth, NaHCO₃:Na₂CO₃ of 5:1 solution with 75 mmol/L and pH 9.63 was used in sorghum at the stage of three leaves and one heart. The root growth index, chlorophyll content, antioxidant enzyme activity and MDA content were measured at 0, 4, 12, 24, 72, and 120 h of stress. The results indicated that the heterologous overexpression of Atvip1 gene could alleviate the damage of saline-alkali stress on the growth of sorghum seedlings, increase the root surface area and root volume, the number of root tips and branches, and also cause the browning of sorghum main roots to appear later and mild symphonys, and the earlier and more lateral roots occurrence. The new leaves could still be normally extended at 72 h and present little effect on the growth of aboveground. Overexpression of Atvip1 gene could increase the activity of O₂^-· resistance, decrease the content of MDA and enhance the activities of antioxidant enzymes in transgenic sorghum roots. SOD, CAT and GR had obvious effects at 4-12 h during the early stage of stress, respectively. All enzymes played roles during the middle of stress at 24-72 h. CAT and GSH-PX played important roles at the later stage of stress at 120 h. On the base of differential transcriptome analysis of saline-alkali stress, COG analysis of differentially expressed genes(DEGs) showed that defense mechanisms accounted for a relatively large proportion during various periods, and 42 DEGs related to antioxidant enzymes were obtained. Heterologous overexpression of Atvip1 gene can improve the resistance of transgenic sorghum to saline-alkali stress by alleviating the effects on photosynthesis, growth and development, reducing the damages of reactive oxygen species and membrane damage.

In order to study the physiological response and difference of nitrogen metabolizing enzyme activity in leaves of different forage oats in Horqin Sandy Land. The forage oats of Muwang and Tianyan No.1 were applied with 0 (CK), 100, 200, 300 kg/ha pure nitrogen in the proportion of 15%, 40%, 25% and 20% at tillering, jointing, heading and flowering stages. The activities of glutamate synthase (GOGAT), glutamine synthetase (GS), nitrate reductase (NR), glutamic oxaloacetic transaminase (GOT), glutamic pyruvate transaminase (GPT) were measured in flag leaf, inverted two leaf and converse third leaf during the filling period, and the differences of nitrogen metabolizing enzyme activities and their relationship with hay yield of different forage oat varieties under nitrogen application rate were analyzed. The results showed that the hay yield of Muwang and Tianyan No.1 reached the maximum at 200,300 kg/ha nitrogen levels, respectively;The activities of GOGAT, GS, NR, GOT and GPT in the leaves of Muwang and Tianyan No.1 forage oats increased first and then decreased with the increase of nitrogen application, and the enzyme activity was the strongest under N₂₀₀ nitrogen application (except for GOT activity of converse third leaf under N₃₀₀ treatment).Except for GS activity of the third leaf of N₁₀₀ treatment and GPT activity of the second leaf in different nitrogen treatments, GOGAT, NR, GS, GOT and GPT enzyme activities of Muwang were higher than those of Tianyan No.1. This indicated that nitrogen assimilation ability of forage oat variety Muwang was stronger than that of Tianyan No.1.Therefore, in Horqin Sandy Land, the suitable amount of topdressing nitrogen fertilizer for planting Muwang was 200 kg/ha, while for planting Tianyan No.1, topdressing nitrogen fertilizer of 300 kg/ha could obtain higher hay yield. GOT and GPT activities were the key enzymes for screening forage oat varieties with high nitrogen use efficiency.

The purpose of this study was to reveal the intercropping advantage of sorghum-soybean intercropping system. Field experiments were conducted in 2018 and 2019 in Fenyang of Shanxi Province. This study included nine treatments, sole-higher sorghum Jinza 22 (G1), sole-lower sorghum Jinza 34 (G2), sole-soy bean(D), 2 rows sorghum and 2 rows soybean(2G1:2D, 2G2:2D), 2 rows sorghum and 3 rows soybean(2G1:3D, 2G2:3D), 2 rows sorghum and 4 rows soybean (2G1:4D, 2G2:4D). Sorghum and soybean yield, land equivalent ratio, water and nutrient use efficiency of different sorghum-soybean intercropping treatments were investigated. The results showed that the 1 000-grain weight and spike weight of sorghum in intercropping system were no significant difference than that of sole sorghum. However, the pods number of soybean had significant difference between different treatments. Compared with sole-soybean(D), the pods number of soybean in 2G1:2D, 2G2:2D, 2G1:4D, 2G2:4D decreased by 37.89%, 32.16%, 22.46%, 21.51%, respectively. The land equivalent ratio (LER) and water equivalent ratio (WER) in the all intercropping system were more than 1, indicating that there were some advantages in land and water use. The nutrient advantage of intercropping system was due largely to a higher total nitrogen accumulation than that of the sole system. Compared with 2G2:2D, the average LER, WER, total nitrogen accumulation of 2G1:2D increased by 8.91%, 8.30%, 4.56%, respectively.The average LER, WER, total nitrogen accumulation of 2G1:4D increased by 10.17%, 9.14%, 4.35%, respectively, than that of 2G2:4D. In the sorghum Jinza 22 and soybean intercropping system, the LER, WER, total nitrogen, phosphorus and potassium accumulation of 2G1:4D were the highest among the intercropping treatments. In conclusion, the LER, water and nitrogen use efficiency by sorghum-soybean intercropping could be improved, and the intercropping advantages of higher sorghum Jinza 22 and soybean were more obvious than that of lower sorghum Jinza 34 and soybean, and the 2G1:4D intercropping system was the suitable combination under the experimental condition.

In order to discover the QTL of barley plant height-related characters, improve the barley plant height-related characters. Chinese forage barley Taixing 9425 and Japanese beer barley Naso Nijo as well as 177 doubled haploid lines, generated from a cross between Taixing 9425 and Naso Nijo, were used as materials to examine the three plant traits of plant height(PH), internode length under spike(SIL), and spike length(SL) in two environments. Characters, combined with the constructed molecular marker linkage map, using Windows QTL IciMaping V4.1.0.0 software based on the complete interval mapping method for QTL mapping analysis, also the genetic characteristics were analyzed. The results showed that:plant height, spike length, and internode length under spike were mainly controlled by genetic factors, and at the same time affected by the ecological conditions and production conditions of the pilot. The heritability of the three traits was 78.98%, 89.31% and 84.50%, respectively; Plant height was extremely significant positive correlation with the spike length and the internode length under the spike. Plant height and spike length, plant height and the internode length under the spike, and spike length and the internode length under the spike were all significantly positively correlated, with correlation coefficients of 0.688, 0.862 and 0.600, respectively, indicating that the higher the plant height, the longer the spike length and the internode length under the spike. The 2 pilot sites mapped 6 QTL for plant height, 5 QTL for spike length, and 4 QTL for internode length under spike. A total of 15 QTL are located on all chromosomes except chromosomes 1 and 6. The LOD value was 3.50-32.46, the explanation rate of phenotypic variation was 1.53%-38.30%. Among them, qPH-4-1, qPH-7-2, qSL-2-1, qSL-2-2, qSIL-2-1 and qSIL-3-2 have not been reported, and may be new loci. This lay the foundation for the improvement of barley plant height-related characters and molecular marker assisted breeding.

In order to clarify the change rule of photosynthetic characteristics and the best fertilization method in different growth stages of sweet sorghum under different fertilization treatments, the field experiment was conducted to study the stomatal conductance (Gs), intercellular CO₂ concentration (Ci), transpiration rate (Tr), net photosynthetic rate (Pn), chlorophyll (SPAD), water use efficiency (WUE) and yield of New Sorghum No.3 under 8 different fertilization treatments, including CK, NK, NP, PK, NPK, M (organic fertilizer), NPKM and 1.5NPKM.The results showed that the changes of Pn, Gs, WUE and SPAD value in sorghum leaves under different fertilization treatments were the same at different growth stages, showing a trend of first increasing and then decreasing, and peaking at grain filling stage. The variation trend of Tr and Ci from flowering stage to maturity stage decreased first and then increased, and reached the lowest value in grain filling stage. At the same growth stage, the photosynthetic characteristics of different fertilization treatments were different, and the photosynthetic characteristics of leaves were affected by fertilization treatments. The Tr, Gs and Ci values of NPKM fertilization treatment at maturity stage were higher than those of other treatments, which were 3.64 mmol/(m²·s),328 mmol/(m²·s),439 μmol/mol, respectively. The correlation analysis showed that Pn of NPKM treatment at flowering stage was significant positively correlated with Tr and WUE, while Pn of NPK treatment was positively correlated with Gs and Ci. The biological yield of all fertilization treatments was significantly higher than CK, among them the biological yield of NPKM treatment reached 94.81 t/ha. The biological yield of NPKM increased 97.95%, 26.65%, 20.24%, 19.57%, 15.16%,14.98% and 11.74% respectively compared with CK, M, 1.5 NPKM, NK, PK, NPK and NP. Fertilization affects the photosynthetic parameters of the leaves of New Sorghum No.3 and was conducive to increasing yield. Therefore, it is feasible to use high photosynthetic efficiency breeding to improve biological yield. In order to alleviate the obstacle of continuous cropping of sweet sorghum, different proportion of fertilizer should be adopted. In a word, NPKM is the best fertilization mode to improve photosynthetic conditions and maximize yield, so it is preliminarily confirmed that NPKM is the best fertilization mode to promote the growth and development of continuous cropping sorghum in arid area.

In order to clarify the continuous cropping barrier mechanism under the condition of large-scale cropping of millet in mountainous areas,representative soil samples were collected from 0-3 years of continuous cropping in Huangqi of Fengning County and Xichengshui of Lincheng County.Through the determination and analysis of the content of total nitrogen,available phosphorus and available potassium,soil pH value,stress-resistance activity of millet plants,and microbial community species and abundance in the soil,the mechanism of continuous cropping obstacle was preliminarily revealed from the physiological and pathological aspects.The results showed that with the increase of continuous cropping years,soil total nitrogen continued to decrease,the content of available phosphorus and available potassium first increased and then decreased,the soil pH value increased year by year,the activity of SOD continued to increase,and the activity of POD and CAT first increased and then decreased.With the increase of continuous cropping years,the species and quantity of soil microbial community changed regularly,the abundance of some beneficial bacteria such as Actinobacteria and Gemmatimonadetes decreased year by year,and the abundance of pathogenic bacteria such as Ustilaginomycetes increased year by year.

In order to explore the genetic basis of drought resistance and guide drought resistance breeding, mapping of QTL associated with drought resistance at germination stage of foxtail millet was done. An F₂ segregating population was constructed using 100 individuals derived from a cross between Shanxi 2010 and K359×M4-1. A genetic linkage map was constructed based on 2b-RAD sequencing, which was then combined with the phenotypic trait of drought resistance for QTL mapping. The results showed that drought resistance at germination stage of foxtail millet was a complex quantitative trait and controlled by multiple genes. A genetic map containing 583 SNP makers was constructed by 2b-RAD of parents and F₂ population. The map covered 9 chromosomes of foxtail millet, with an average number of 64.8 and an average genetic distance of 0.97 cM between markers. A total of 3 QTLs were identified:qSIDR-5a, qSIDR-6a and qSIDR-6b, located in foxtail millet chromosome 5 and 6, respectively, which explained 12.4%-14.3% of phenotypic variation. Among them, phenotypic contribution rate of qSIDR-5a was the highest, which explained 14.3% of phenotypic variation. These QTLs were not included in the same chromosome interval as the identified drought resistance related QTLs of foxtail millet, and thus were described as new candidate gene loci associated with germination stage drought resistance.These QTLs can be used for fine mapping and gene cloning, as well as molecular regulation mechanism of drought resistance of foxtail millet.

To study the effects of salt stress on growth and physiological characteristics of sorghum at different growth stages(elongation, flowering, and maturity), two sorghum varieties with different salt tolerances, Gaoliangzhe(salt tolerance) and Henong No.16(salt sensitive), were planted at four salt treatment levels(CK:0 g/kg, S3:3 g/kg, S5:5 g/kg, S7:7 g/kg). Moreover, the two varieties were compared under different salt treatment levels, plant morphology, root morphology, leaf photosynthetic characteristics and antioxidant enzyme activities at different growth stages. The results showed that with increasing salt treatment concentration, the antioxidant enzyme activity and relative chlorophyll content(SPAD) of the two varieties increased first and then decreased. The antioxidant enzyme activity reached the maximum value under S3 or S5 treatment, and there were significant differences between the maximum and CK. With the increase of salt treatment concentration, the malondialdehyde(MDA) of the two sorghum varieties increased significantly, which S7 treatment was significantly higher than CK. Under the same treatment, the antioxidant enzyme activity of salt-tolerant varieties(Gaoliangzhe) was higher than that of salt-sensitive varieties(Henong No.16), but the content of MDA was lower than that of salt-sensitive varieties. The photosynthetic capacity of the two varieties was significantly affected by salt stress. In elengation, S7 treatment significantly reduced the Pn of Gaoliangzhe, and Ci of the two varieties under S7 treatment was higher than that of CK. Under salt stress, the growth of the sorghum aerial portion and underground portion of sorghum were affected. The basal stem diameter, total length of root, root surface area, number of root tips, and number of root branches for two varieties reached the maximum under S3 treatment. And basal internode length, plant height, total length of root and root volume reached the lowest value under S7 treatment. In addition, grain fat content and grain starch content in two sorghum varieties decreased under salt stress.The grain tannin content was significantly higher than CK in low-salt (S3, 3 g/kg). In general, low-salt can promote the growth of sorghum, while medium-salt (S5, 5 g/kg) and high-salt (S7, 7 g/kg) conditions have a significant inhibitory effect on sorghum growth. And Gaoliangzhe is more salt-tolerant than Henong No.16.