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.

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.

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.

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 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.

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.

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 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 explore the suitable nitrogen application,the influence of dry matter and nutrient element accumulation and distribution under different N application levels on buckwheat was studied. Field experiment was conducted under different N application rates N₀,N₁,N₂,N₃ and N₄(0,30,60,90,120 kg/ha). The results showed that buckwheat dry matter first increased and then dropped with the increment of nitrogen application rate. When the nitrogen application rate was N₂,the buckwheat dry matter reached the highest. But when the nitrogen application rate was N₃,the seeds dry matter and distribution rate reached the highest. The results also showed that seeds nitrogen,phosphorus and potassium contents first increased and then dropped with the increment of nitrogen application rate.When the nitrogen application rate was N₃,the seeds nitrogen,phosphorus and potassium contents reached the highest. The seeds nitrogen,phosphorus and potassium distribution rate increased with the increment of nitrogen application rate,but it decreased in stems and leaf. The amounts of nutrients which needed for the formation of 100 kg seeds of buckwheat were N 7.09 kg,P₂O₅ 4.15 kg,K₂O 8.74 kg and the rate was 1.00:0.59:1.24.The production efficiency of N,P₂O₅,K₂O first increased and then dropped with the increment of nitrogen application rate. When the nitrogen application rate was N₃,the production efficiency of N,P₂O₅,K₂O reached the highest.With the increase of the amount of nitrogen fertilizer, the dry matter production efficiency of nitrogen and phosphorus first increased, then decreased, and then increased. The dry matter production efficiency of potassium gradually increased, and the production efficiency of N₄, nitrogen, phosphorus and potassium dry matter reached the highest level. Considering the buckwheat dry matter and nutrient element under the experimental conditions,N application rate of 90 kg/ha identified to be the suitable amount.

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.

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.

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 this research,a field orientation experiment on sorghum-maize rotation was conducted.The effects of different fertilization conditions on the growth,nutrient,soil enzyme activity and microbial activity of sorghum was studied.The experimental results showed that different fertilizer could significantly increase the jointing stage of sorghum plant height,stem diameter,number of pieces and index pages visible leaf area,as well as sorghum yield and grain weight per spike (P<0.05).Each processing production order of IF+M+S > IF+M > M+S > IF > CK,compared to the control,the range of yield increase of sorghum in different fertilization levels were 80.6%-120.7%,respectively,reaching a significant level,and among which IF+M+S treatment was the best.All values of inorganic fertilizer treatments were slightly higher than that of no fertilization treatment. The organic fertilizer treatment increased the soil nutrients and organic matter content of sorghum, compared with the inorganic fertilizer treatment. The total N, available P, available K, organic matter of IF+M+S treatment were 1.95, 10.36, 2.01, 1.83 times of CK, respectively (P<0.05). Soil enzyme activity of fertilization treatments in different growth periods was higher than no fertilization (CK),in which the most was the treatment of IF+M+S,activity of alkaline phosphatase in jointing stage and harvest stage,urease in harvest stage,invertase in jointing stage,flowering stage and harvest stage were all significantly higher than that of inorganic fertilizer treatment (P<0.05).The application of organic fertilizer or application combined with inorganic fertilizer could improve the soil microbial community functional diversity and the capability of utilizing carbon sources.And the treatments containing organic fertilizer and straw manure were more conducive to improve soil microbial diversity than other organic fertilizer treatments.

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 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.

Leaf color mutant is one of the ideal materials to explore the development mechanism of chloroplast and the utilization of C4 light energy in foxtail millet. To study the molecular mechanism of leaf color mutant in foxtail millet,we screened and identified a stripe leaf mutant wsl2 from the EMS mutagenesis library of the main variety Changnong 35. The mutant was studied through phenotype identification,genetic background detection and genetic analysis,location of the mutant gene rapidly and precisely with MutMap method and developing co-isolated molecular markers according to the mutation site. The results showed that wsl2 showed stripe leaf phenotype at seedling stage,but returned to normal leaf phenotype from jointing stage. wsl2 had the same genetic background as the wild type by detecting the genetic background. And wsl2 was controlled by a recessive nuclear gene with genetic analysis. The association interval contained 9 non-synonymous mutant genes by MutMap method. Seita.9G561800 encoded a PsbP-like protein associated with chloroplast,containing 6 exons and 5 introns. A G/T base mutation occured at 77 bp in the first exon,resulting in an arginine(R)becoming leucine(L). The mutation site of candidate gene in wsl2 mutant was further verified by the dCAPS marker MRI498-1(Cac8 Ⅰ)and the co-isolation marker MRI501-3. This study identified a new stripe leaf mutant wsl2, which laid a theoretical foundation for further study on the mechanism of photosynthesis reaction of PsbP gene,enriched the resources of leaf color mutant,and verified the effectiveness of MutMap method in cloning mutant gene in foxtail millet.

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 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.

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.

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.

Analysis of the expression pattern of florigen gene (Hd3a)under different photoperiod conditions,aims at revealing the role of florigen gene that played in photoperiod-regulated flowering process of foxtail millet. First,a SiHd3a gene sequence(Seita.4G067600,named SiHd3a)on Chr.4 of foxtail millet was obtained by bioinformatics method and according to the transcribed sequence of Seita.4G067600,a pair of specific primers were designed successfully. Then the total RNA of millet land race Huangmaogu was extracted and after reverse transcription the cDNA sequence of SiHd3a gene was obtained by RT-PCR technology. The cDNA sequence was 792 bp which included a 537 bp CDS region that coding 178 amino acids. The molecular weight,isoelectric point of SiHd3a protein were 19.74 ku and 6.82 respectively,which was preliminarily judged as a hydrophilic protein. The proportion of irregular curl was the highest in protein secondary structure(43.26%),following it were extended chain(β-sheet,29.21%),α-helix(16.29%)and β-turn(11.24%). Subcellular localization analysis showed that SiHd3a protein was located in the cytoplasm and intercellular substance. Phylogenetic analysis based on Hd3a protein sequences showed that there was a close relationship between foxtail millet and crown,maize,sorghum,but a distant relationship between foxtail millet and rice. Semi-quantitative PCR showed that under short-day condition, SiHd3a gene gave a circadian rhythm expression pattern,with two expression peaks at six am,and twelve am respectively. While under long-day condition, SiHd3a gene gave almost stable expression level in 24 hours. It could be speculated that the diurnal expression pattern difference of SiHd3a gene between long-day and short-day might be the cause leading to photoperiod sensitivity of foxtail millet.

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 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.

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.

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.

Foxtail mille is a C₄ gramineous crop with drought resistance, barren-tolerance, wild adaptability and high adverse resistance. To reveal the role of the genes expression characteristics under light and stress of foxtail millet, the genes related to abiotic stress were explored in this experiment. A PPDK gene, named as SiPPDK2, was identified in foxtail millet genome by bioinformatics method. SiPPDK2 was located on chromosome 3 in foxtail millet genome, which contained 18 introns. It contained 3 transcripts and primary alternative transcript encoding 945 amino acids residues. Subcellular localization predictions indicated that SiPPDK2 was mainly localized in chloroplasts. Functional domain and multiple sequence alignment analysis revealed that SiPPDK2 protein had a more closely relationship with PPDK proteins in maize, sorghum and rice. RT-PCR analysis showed that the expression of SiPPDK2 at its seedling stage was induced by PEG, ABA, salt and low temperature treatments. Further studies indicated that SiPPDK2 was involved in drought stress and different light intensity at the jointing, heading and filling stage, in which the expression was significantly increased under the drought condition at heading and filling stages and under the low light condition at jointing and filling stage. cis-elements analysis revealed that hormonal, stress, light, and other growth-related responses cis-elements were present in the promoter region of the SiPPDK2. The results speculated that SiPPDK2 is involved in the response to abiotic stress in foxtail millet.

Tillering is an important trait related to yield in many crops,and is the same for yield improvement of foxtail millet. However, the genetic mechanism of tillering in foxtail millet (Setaria italica) remains largely unknown. To accelerate mapping of relevant QTLs or genes, a restriction site-associated DNA sequencing (RAD-seq) approach, MSTmap and WinQTLCart 2.5 were employed to identify QTLs responsible for tillering in two F₂ populations called Cross AJ (543 F₂ individuals) and Cross HC (131 F₂ individuals). A total of six QTLs including qAJTN1, qAJTN5, qAJTN7-1,qAJTN7-2, qAJTN7-3 and qAJTN9, were identified in Cross AJ, explaining 0.7%-9.8% of the phenotypic variance, and two QTLs including qHCTN5 and qHCTN7 were identified in Cross HC, explaining 1.4%-8.3% of the phenotypic variance. Of which qAJTN1, qAJTN5, qAJTN7-2, qAJTN9 and qHCTN5 were newly identified QTLs, and qAJTN7-1, qAJTN7-3 and qHCTN7 were consistent with previous reports. Meanwhile, we screened the insertions and deletions in the QTL regions compared with the reference genome, insertion-deletion (InDel) markers linked with tillering were developed. These results of this study will facilitate the revelation of the genetic mechanism of tillering and molecular marker-assisted breeding of foxtail millet.

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.

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 effect of plastic film mulching on the growth and yield of millet, clarify the mechanism of plastic film increase production, and provides theoretical basis for the whole film dibbling technology in the summer crops, a study on influence mechanism of film mulching on growth development and yield had been conducted. The test using spit plot experiment design was executed in Shijiazhuang luancheng Qiema experimental station, 2015. The main plot had two treatments, respectively is plastic mulch and no plastic mulch. The split plot had three varieties, respectively is Jigu 19, 36 and 38. Under the condition of plastic mulch and no plastic mulch, the morphological characteristics, yield and its traits, flag leaf SPAD values and flag leaf net photosynthetic at heading stage millet rate were studied. Results show that:compared with no plastic mulch, the sum area of top three leaves increased 12.83-26.36 cm², chlorophyll SPAD value increased 8.2%-17.1%, net photosynthetic rate increased 34.9%-34.9%, and yield increased 7.3%-10.8%. Yield performance of Jigu 36 was better than Jigu 19 and Jigu 38, and yields of three varieties (especially Jigu 38) were improved by film mulching. Yield had a significantly positive correlation with 2nd top leaf area, net photosynthetic rate, leaf area and the top three leaves area. Flag leaf area was positively correlated with grain weight per ear and ear length. Therefore, the growth and developing physiological stage of top leaves (especially 1st top leaf), film mulching affected the growth of ear and increased millet yield eventually.

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.

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.

To realize rational and effective use of N fertilizer in brewing sorghum,a field trial with a brewing sorghum variety Jinza 22 was conducted to study the effects of different N fertilizer rates (0,75,150,225,300,450 kg/ha)on yield of brewing sorghum and nitrogen use efficiency.The results showed that nitrogen application increased effectively grain yield and net profit of sorghum in the range of 0-450 kg/ha N applied,but grain yield increased and then decreased with the increased of nitrogen application.The relationship between yield and N fertilizer rates could be expressed as y=-0.037x²+17.759x+5 874.41 (R²=0.878 1).With the increased of N application,N partial factor productivity and N fertilizer use efficiency significantly decreased,N absorption efficiency gradually reduced and N use efficiency had a largely down trend.The highest yield and net profit were obtained by the N treatment of 225 kg/ha (N₂₂₅).Compared with the treatment of no nitrogen application,yield of N₂₂₅ was increased extremely significantly with the rate of yield increased of 37.64%,N agronomic efficiency of 9.96 kg/kg,N partial factor productivity of 36.42 kg/kg,N fertilizer use efficiency of 38.70% and N balance of 3.07 which kept roughly the N balance.Comprehensive analysis of the indicators,N fertilizer application rate of 225 kg/ha is the optimum level for high-yield,high-income and relative high-N use efficiency of sorghum variety Jinza 22 under the experimental condition.

In order to select new breeding materials of Ruthenia Medic with outstanding.In this study,we used AFLP and SSR markers to investigate the genetic diversity in 15 wild Ruthenia Medic accessions from Seven provinces and autonomous regions of China.A total of 109 alleles were detected using 18 pairs of SSR primers,and 640 bands containing 472 polymorphic bands were revealed using 8 pairs of AFLP primers.The mean Nei's gene diversity,Shannon's information index and genetic differentiation coefficient obtained by AFLP were higher than those obtained by SSR.The genetic distances and similarities among the 15 wild accessions demonstrated their close phylogenetic relationship.Dendrograms with arithmetic average based on both AFLP and SSR data clustering showed that the 15 accessions could be grouped into four main clusters.However,the order of clustering did not completely agree with the geographical distribution.A similar clustering pattern was obtained using principal coordinate analysis.The Mantel test identified a highly significant correlation of the AFLP and SSR data.Thus,combined AFLP and SSR more efficiently estimated and validated the genetic diversity of the Ruthenia Medic accessions.These results can aid the formulation of breeding and germplasm conservation strategies for Ruthenia Medic.