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Seed shattering is a major factor limiting rice production, and breeding new rice varieties with moderate seed shattering is a key challenge faced by rice breeders worldwide. Rice is the most important cereal crop in China, plays a vital role for national food security. Seed shattering is one of the most important traits during rice domestication, and the abscission zone is the important region to control seed shattering. Compared with wild rice, cultivar has eliminated the seed shattering with partially developed abscission layer. Seed shattering not only has a direct impact on the yield, but also affects the way of its mechanical harvest. In order to breed rice varieties with moderate seed shattering in agricultural production, it is necessary to mine and utilize important seed shattering genes and introduce them into excellent rice varieties for genetic improvement, so as to breed new rice varieties suitable for mechanical harvesting with moderate seed shattering. Several seed shattering genes had been identified by map-based cloning, such as SH4/SHA1, qSH1, OsSh1/ObSH3, and their functional mechanisms had been analyzed. At the same time, new rice materials with moderate seed shattering have been successfully developed through CRISPR/Cas9 gene editing technology, gamma ray mutagenesis technology and gene introduction methods. Seed shattering has an important effect on grain yield and rice harvesting methods, in this paper, we reviewed the methods, physiologic basis, the identification of seed shattering genes and genetic mechanism of seed shattering in rice. At the same time, it is proposed that by using the important genes in excellent rice germplasm resources, could provide reference for exploring the mechanism of rice seed shattering, and breed new rice varieties suitable for mechanical harvesting with moderate seed shattering.

【Objective】Based on whole genome identification and analysis of soybean LOX gene family members, to understand the taxonomic evolutionary relationships of each member, to study the expression specificity of each gene member in different tissues and their response to abiotic stress, which provided a theoretical basis for further research on the molecular characteristics, evolutionary process, and function of the LOX gene family. 【Method】Based on the LOX protein sequences of rice and Arabidopsis species in Ensembl database, BLASTP alignment of homologous LOX protein sequences in soybean whole genome database was performed, and MEGA X software was used to construct a phylogenetic tree; Using website MEME for protein conserved motif analysis; Using online software GSDS 2.0 to analyze gene structure; Using TBtools for chromosome localization drawing; Analyze soybean LOX family replication genes using McscanX; Using the PlantCARE website to predict the promoter elements of soybean LOX gene family; Draw gene expression heatmaps of soybean under different tissues and abiotic stress using TBtools, and develop molecular markers for the excellent allele variant GmLOX15A1^-G/A significantly correlated with 100-seed weight.【Result】A total of 43 LOX genes were identified in soybean, unevenly distributed on 13 chromosomes. Collinearity analysis indicates that the GmLOX gene has undergone extensive replication during the evolutionary process. Meanwhile, 39 different types of cis regulatory elements were detected in the LOX gene promoter, indicating that they may be involved in different pathways such as growth and development, light response, stress response, and hormone induction. Expression pattern analysis revealed that the LOX gene has different levels of expression in different tissues of soybean, indicating that members of this family have tissue and spatiotemporal expression specificity. Under drought stress conditions, the GmLOX gene was significantly differentially expressed in soybean roots and leaves (P<0.05). Among them, GmLOX3A3, GmLOX7A1, GmLOX20B1, GmLOX13A1, and GmLOX20A2 were significantly upregulated or downregulated in roots and leaves, suggesting that the GmLOX gene may play an important role in response to stress. At the same time, it was found that GmLOX15A1 is highly expressed in grain tissue and there is an excellent G/A allele variation in the seventh exon of the gene coding region. Molecular markers were developed for this variant site, and the correlation between different haplotypes of GmLOX15A1 and 100-seed weight was analyzed using 1 200 soybean germplasm resources from different ecological regions over a period of 2 years. The results showed that compared to the GmLOX15A1^-A genotype, the average 100-seed weight of soybean germplasm carrying the GmLOX15A1^-G allele gene increased by 2.33 g (P<0.001). 【Conclusion】A total of 43 members of the LOX family were identified in soybeans, which can be divided into 3 subfamilies. The promoter region of the GmLOX gene contains a large number of cis acting elements that respond to hormones and stress, playing different roles in drought stress response. Among them, GmLOX15A1 is highly expressed in grain tissue and there is an excellent G/A allele variation in the seventh exon of the coding region of this gene. Compared with the GmLOX15A1^-A genotype, the average 100-seed weight of soybean germplasm carrying the GmLOX15A1^-G allele gene is significantly increased by 2.33 g. This locus can be used as an excellent haplotype for genetic improvement of soybean grain size.

【Objective】This study was conducted to screen the concentration of soda saline-alkali stress solution and the determination index of saline-alkali tolerance, to establish the identification method of saline-alkali tolerance to large-scale identification of sorghum germplasms. The saline-alkali tolerance of the core germplasms of grain sorghum were comprehensively evaluated, and the saline-alkali tolerant germplasms were identified and selected to provide a germplasm basis for further breeding of saline-alkali tolerant parents and hybrids.【Method】The main components of saline-alkali soil of in The Songnen Plain are Na₂CO₃ and NaHCO₃. This experiment used 50 mmol·L^-1 NaHCO₃﹕Na₂CO₃=9﹕1 as a stress solution to simulate the moderate saline-alkali environment in Songnen Plain, the pH is 9.19, Salinity is 0.21%. Eight traits, including seedling height, root length, seedling fresh weight, root fresh weight, seeding dry weight, root dry weight, root-shoot ratio fresh weight and root-shoot ratio dry weight were used as measurement indexes and the saline-alkali tolerance characteristics of 285 sorghum core germplasms at seedling stage were identified. Principal component analysis was used to screen the salt-alkali tolerance identification indexes of grain sorghum at seedling stage and establish a mathematical model for salt-alkali tolerance evaluation at seedling stage. The saline-alkaline tolerance of 285 sorghum germplasms was classified by cluster analysis, and the germplasms with strong saline-alkaline tolerance were screened.【Result】50 mmol·L^-1saline-alkali stress showed inhibitory effects on 8 indexes of 285 sorghum germplasms, the average values of saline -alkali resistance coefficients are 0.794, 0.785, 0.565, 0.554, 0.802, 0.638, 0.978, and 0.841.Under saline alkali stress, 8 indexes showed significant positive correlations; the seedling height and root fresh weight could be used as the indexes for the identification and evaluation of soda saline-alkali stress in sorghum seedling stage by principal component analysis; The evaluation model of saline-alkali tolerance characteristics of sorghum seedlings was summarized by multiple linear regression analysis Y=0.097X4+0.171X2+0.201X6+0.157X1+0.105X3- 0.147, it can be used for comprehensive evaluation of multiple indicators. 285 grain sorghum core collections were divided into 5 grades by cluster analysis, strong saline-alkali tolerance, saline-alkali tolerance, intermediate type, sensitive type and extremely sensitive type, Among them, there were 8 strong salt-tolerant germplasms, 8 salt-tolerant germplasms, 112 intermediate germplasms, 134 sensitive germplasms and 23 extremely sensitive germplasms. The saline-alkali tolerant germplasm and extremely sensitive germplasm were planted in the moderate saline-alkali soil (pH 8.5-9.5, Salinity 0.3%) for verification in Zhenlai County of western Jilin Province. The average seedling emergence rate of strong saline-alkali tolerant germplasm was 45.4%, and the average seedling height was 23 cm. The average seedling emergence rate of salt-tolerant germplasm was 31.3%, and the average height was 20.9 cm. The average emergence rate of extremely sensitive germplasm was 20%, and the average seedling height was 12.3 cm.【Conclusion】8 strong soda saline-alkali tolerant germplasms and 8 saline-alkali tolerant germplasms were screened out from 285 sorghum germplasms resources with 50 mmol·L^-1 soda saline-alkali concentration (NaHCO₃﹕Na2CO₃=9﹕1). The seedling height and root fresh weight could be used as the preferred evaluation indexes for the identification of saline-alkali tolerance at seedling stage.

【Objective】The objective of this study was to evaluate the effects of one-off irrigation and nitrogen (N) fertilizer management on grain yield and quality in dryland winter wheat (hereinafter referred to as wheat).【Method】From 2020 to 2022, the split-plot field experiment was conducted at the Mengjin, Yichuan and Luoning counties of Luoyang city in Henan province, China, in the typical dryland wheat production area at the intersection between Loess Plateau and Huang-Huai-Hai Plain. The two irrigation levels of no-irrigation during wheat growth period (I0) and soil-moisture-based one-off irrigation after regreening (I1, one-off supplemental irrigation was conducted to 85% of field capacity when the soil water content in the 0-40 cm soil layer after wheat regreening was lower than 60% of field capacity at the first time, there was only this irrigation during the whole growth stage) were assigned as the main plots; and the four N fertilizer managements of N0, N120, N180 and N240 were set as sub-plots, where N rates were 0, 120, 180 and 240 kg·hm^-2, respectively, and all of them were applied at sowing under I0 treatment, and 50% as basal, and 50% were applied along with the one-off irrigation under I1. The grain yield and protein yield, zinc content, protein and its components content, and main processing quality indicators of wheat were determined. 【Result】 Compared with I0, I1 significantly increased wheat grain yield and protein yield by 11.5%-73.0% and 9.1%-57.0%, respectively, in which the amplification enlarged with the increase of N rates, and that in the 2020-2021 was higher than that in the 2021-2022. However, I1 reduced the contents of zinc, and protein and its components in wheat grain, as well as the most indicators of processing quality compared with I0. Except for the globulin content at Yichuan in 2020-2021, compared with I0, I1 significantly decreased the content of zinc, protein and its components, and the processing quality of wheat grain. Among them, the content of zinc, albumin, globulin, gliadin, and glutenin were decreased by 5.0%-13.8%, 4.5%-14.1%, 6.4%-17.3%, 2.3%-24.8%, and 8.0%-13.9%, respectively, and the development time, stability time, wet gluten content, sedimentation value, extensibility, and maximum resistance were decreased by 5.3%-23.2%, 8.5%-51.1%, 2.0%-13.3%, 4.5%-18.1%, 4.6%-12.2% and 3.3%-10.6%, respectively. With the increase of N rate, wheat yield firstly increased and then decreased and wheat protein yield firstly increased and then stabilized under I0, while wheat yield firstly increased and then stabilized and wheat protein yield gradually increased under I1, however, the wheat quality indicators mostly tended to increase firstly and then stabilized under both I0 and I1. There were no significant differences between N240 and N180 for most quality indicators, but most of them were significantly higher than N120. The quality indicators of wheat grain under N120 were also significantly higher than that under N0. Considering the interaction effect, irrigation levels and N managements had significant interaction effects on yield and protein yield, but there was no interaction effect on most quality indicators. The grain yield under I1N180 did not change significantly but the protein yield was significantly decreased by 3.9%-4.9% compared with I1N240, however, both the grain yield and protein yield under I1N180 were significantly increased compared with other treatments. Although the content of protein and protein components and the processing quality in wheat grain under I1N180 were significantly lower than that under I0N180 and I0N240, these quality indicators were not significantly lower than that under I1N240. 【Conclusion】 The soil-moisture-based one-off irrigation after regreening combined with the N rate of 180 kg·hm^-2 and 50% N topdressing along with irrigation (I1N180) could synchronously improve the grain yield and stabilize the grain quality in dryland wheat. Therefore, I1N180 was suitable for wheat production in the dryland area, where one-off irrigation was guaranteed due to High-Standard Farmland Construction Program.

【Objective】 Xinjiang cotton-growing area has the resource conditions for the formation of different cotton fibers quality types, due to its large spanning range, diverse climate and ecological types. It can provide theoretical bases for cotton-using enterprises to select multi-type, multi-grade and high-quality special cotton and optimize the cotton dominant production area, by studying the regional differences and distribution patterns and clarifying the climatic factors which affect the distribution of raw cotton quality in Xinjiang. 【Method】 Based on the quality certification inspection data of Chinese cotton from 2016 to 2020, the dataset encompassed fiber length, strength, Micronaire, and uniformity. The weighted average method was employed for analyzing the raw cotton quality across different cotton planting regions in Xinjiang. The linear trend slope method was utilized to determine the interannual variation trend of raw cotton quality in each individual county or city involved in cotton cultivation. Subsequently, a comprehensive evaluation of Xinjiang’s raw cotton quality was conducted based on the respective weights assigned to each index.【Result】The fiber length and strength of the northern region were significantly higher than those of the southern and eastern regions by 0.24-0.31 mm and 0.62-1.17 cN/tex. The quality of raw cotton in the Xinjiang Production and Construction Corps was noticeably superior to that of the Xinjiang Uygur Autonomous Region, and the fiber length and strength of raw cotton increased by 0.22 mm and 0.44 cN/tex, respectively. The fiber length ranging from 28.9 to 29.0 mm was predominantly concentrated in Huyanghe City of the Seventh Division (Chepaizi Reclamation Area), Shihezi City of the Eighth Division (Xiayedi Reclamation Area), and Beitun City of the Tenth Division (184 Corp) within the cotton producing region of northern Xinjiang. The strength in the northern region exhibited superior performance, with the strength between 28.4 and 29.9 cN/tex, while it was comparatively lower in the southern region. Micronaire A showed significant concentration in Wujiaqu City of the Sixth Division (Wujiaqu Reclamation Area), Beitun City of the Tenth Division (184 Corp), and Changji City within the cotton producing area of northern Xinjiang. The high-quality regions exhibited a consistent year-on-year growth trend, with fiber length increasing by 0.01-0.07 mm annually. The regions demonstrating this upward trend included Turfan Gaochang District in the eastern region of Xinjiang, Xinhe County, Magaiti County, Wensu County, Shache County, Shule County in the southern region of Xinjiang, and the Third Division of Tulushuk city (Xiaohaizi Reclamation Area). An average annual increase of fracture-specific strength ranging from 0.21 to 0.40 cN/tex primarily concentrated in Xinhe County, Wensu County and Tumushuk City of the Third Division (Xiaohaizi Reclamation Area) within the cotton-producing zone of Southern Xinjiang. Regions with better overall raw cotton quality were primarily concentrated in Manas County in Northern Xinjiang, Wujiaqu City in the Sixth Division (Wujiaqu Reclamation Area), Shihezi City in the Eighth Division (Xiayedi Reclamation Area, Anjihai Reclamation Area, Shihezi Reclamation Area, Mosuowan Reclamation Area), and Wensu County and Awati County in Southern Xinjiang, with fiber lengths ranging from 28.6 to 29.0 mm and strength from 28.4 to 29.9 cN/tex.【Conclusion】The quality of raw cotton in Xinjiang exhibited regional variations, which were influenced by the duration of days with temperatures over 35 ℃. Variety renewal and simplified cultivation were important ways to improve cotton quality and ensure the effective supply of high-quality raw cotton.

【Objective】Stalk rot is a prevalent disease of maize (Zea mays) that severely affects maize yield and quality worldwide. The diseases are caused by several types of fungi and bacteria that are part of the complex of microorganisms. Among which, the ascomycete fungus Fusarium proliferatum has become one of the most aggressive causal agents of maize diseases in China in recent years. The study aims to provide a comprehensive analysis of multi-omics of maize stalks following F. proliferatum inoculation and valuable insights into the molecular basis of the response, including functional annotation and enrichment analyses of the major pathways enriched for differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) of maize conditioning F. proliferatum infection, and to lay theoretical foundation for maize breeding and disease management.【Method】Maize inbred lines ZC17 (ZhengC17, resistant) and CH72 (Chang72, susceptible), with different levels of resistance to F. proliferatum were used for sample collection. Seedlings at the nine-leaf stage with uniform performance were selected for artificial inoculation. Maize plants were inoculated by punching a hole in the stem at the second or third internode above the soil line using a sterile micropipette tip, followed by injection of 50 μL of freshly prepared F. proliferatum inoculum. A similar number of plants were inoculated with PDB as a mock treatment. The wounds were sealed with vaseline after inoculation. The upper and lower stem segments immediately adjacent to the inoculation segments were sampled at 7 dpi (days post inoculation), all individual samples were used for further transcriptome and nontargeted-metabolomics analysis. The inoculated internodes of the individual plants were split and symptoms were observed for evaluating of SRS_A (stalk rot score on average) and DSI (disease severity index). Multiple bioinformatics tools were used to conduct in-depth analysis of the transcriptome sequencing data and metabolomics data, and the DEGs were verified by real-time fluorescence quantitative PCR (RT-qPCR).【Result】Phenotypic and physiological characteristics indicated that the inoculated group of samples from the resistant inbred line ZC17 showed significantly lower lesion areas and symptoms than those of the sensitive inbred line CH72 after inoculation with F. proliferatum. The SRS_A and DSI of the ZC17 and CH72 stalks were consistent with the symptom phenotypes: the susceptible inbred CH72 had approximately 2.48-fold more SRSAs than the resistant inbred ZC17 line, and its DSI increased by 35.36% compared to that of ZC17. The results of the principal component analysis (PCA) showed a high reproducibility of the samples within the group. In PC1, ZC17 and CH72 were separated from each other. In PC2, FP group and MK group were separated from each other. The DEGs in the two comparison pairs (ZC17_FP vs. ZC17_MK, CH72_FP vs. CH72_MK) were analyzed. More DEGs were found in CH72 than those of ZC17 post inoculation, whereas nearly 50% of the DEGs share the same trend of expression between the two comparison pairs. Functional annotation and enrichment analysis found that DEGs and DEMs were enriched in pathways such as biosynthesis of plant secondary metabolites, phenylalanine metabolism, biosynthesis of plant hormones, and plant-pathogen interactions. Integrated analysis of transcriptomics and metabolomics data revealed that phenylalanine, tyrosine, and tryptophan biosynthesis and phenylalanine metabolism were significantly enriched in both the transcriptomic and metabolomic data for CH72 and ZC17. This result suggested that these pathways play a key role in the maize response to F. proliferatum. In addition, transcriptional factors of bHLH, MYB, NAC, and WRKY families were significantly activated after fungal inoculation, demonstrating the important role of transcription factors in the maize response to F. proliferatum infestation. To further confirm the reliability of the sequencing data, 11 genes were randomly selected for qPCR validation, which showed that the trends of the RNA-Seq and qPCR results were consistent in both CH72 and ZC17, Spearman rank correlation analysis also showed high concordance between the RNA-Seq and qPCR results (r=0.75, P=7.5e-05).【Conclusion】Phenylalanine metabolism-related pathways are crucial in maize response to F. proliferatum stalk rot. Key enzymes such as C4H, PAL, ADT, GOT and significantly up-regulated metabolites such as 2-coumaric acid, 3-hydroxycinnamic acid, indole, phenylalanine, tryptophan and tyrosine play an important role in plant disease resistance. The potential disease resistance-related transcription factors, genes and metabolites excavated in this study can provide an important basis for further analysis of the molecular response mechanism of maize to F. proliferatum stalk rot.

【Objective】In the past 10 years, the weed communities in the winter wheat fields in Henan Province have changed significantly. The objective of this study is to clarify the succession of weed communities in the six major planting areas in Henan Province, analyze the reasons of weed succession, and to provide a theoretical basis for the establishment of accurate control strategy of weeds in winter wheat fields.【Method】A total of 378 plots in 17 cities of Henan Province were sampled from November to December in the 2023 to investigate the weed species and weed number in winter wheat fields, compared with the results of 2013, the weed community composition in six major planting areas of winter wheat fields in Henan Province was determined, and the weed community change law was analyzed.【Result】The characteristics of weed communities in winter wheat fields in Henan Province were: (1) Gramineous weeds developed rapidly, Aegilops tauschii, Lolium multiflorum, Bromus japonicas, and Alopecurus myosuroides gradually spread from the local area to the whole province, almost covering the whole province major planting areas at present. Among them, A. tauschii and B. japonicus mainly occurred in dry-stubble wheat fields. In 2013, 14th, 15th, 27th and 35th relative abundances of the four weeds were ranked, respectively, but relative abundances ranked 2nd, 5th, 8th and 15th, respectively, in 2023. (2) Galium aparine and Veronica persica had always been the dominant broad-leaved weeds in winter wheat fields in Henan Province, with relative abundance of 26.89% and 10.68% in 2023, respectively. In the past 10 years, two surveys showed that the comprehensive relative abundance of G. aparine ranked first, G. aparine caused great damage in both dry-stubble wheat field and rice-stubble wheat field, and V. persica had risen from 6th to 3rd. (3) G. aparine, A. tauschii, V. persica, and Descurainia sophia became the dominant weeds in winter wheat fields in Henan Province. In 2013, only G. aparine and Capsella bursa-pastoris had relative abundance of more than 10%, which was 17.38% and 10.92%, respectively, but in 2023, the relative abundance of G. aparine, A. tauschii, V. persica, and D. sophia exceeded 10%, which was 26.89%, 13.45%, 10.68%, and 10.65%, respectively. (4) The damage of regional dominant weeds was also serious, such as Lamium amplexicaule, Raphanus raphanistrum, Malachium aquaticum, Euphorbia helioscopia, Lithospermum arvense, and Geranium carolinianum. In addition, regional harmful weeds such as Lapsana apogonoides, Mazus japonicus, and Alopecurus aequalis were mainly distributed in rice-stubble wheat fields.【Conclusion】The changes of the weed communities in winter wheat fields in Henan Province are mainly caused by the changes of farming systems, the spread and invasion of malignant weeds and the development of weed resistance. Cross-regional operation of combine harvester and human unconscious carrying and spreading are also important factors to promote the change of weed community. Therefore, in the prevention and control of weeds in winter wheat fields in Henan Province, the integrated weed control strategies, such as combining chemical herbicides with agronomic measures, the precise selection of herbicides according to the field grass phase in different planting areas and using herbicides with different mechanisms, should be promoted.

【Background】Organic fertilizer substitution (OF) is an effective chemical fertilizer reduction strategy, which can change the ratio of soil organic carbon to inorganic nitrogen (N), so as to regulate nitrous oxide (N₂O) emission. Similarly, arbuscular mycorrhizal fungi (AMF) forms a symbiotic strategy with most terrestrial plants, increases plant soil nutrient uptake, and affects soil N₂O emission. However, the interactive effects of both OF and AMF on soil N₂O emissions are poorly understood, especially in different agricultural soil environments, and the mechanism of their interaction is also unclear. 【Objective】 This study aimed to explore the mechanical effects of both OF and AMF on soil N₂O emissions during maize growth periods in different soil types, so as to provide the appropriate methods to reduce chemical fertilizer application for farmland management.【Method】Taking Shajiang black soil (SJ) and Fluvo-aquic soils (CT) as research object, a two factor experiment with organic fertilizers replacing chemical fertilizers (0%OF: only chemical N fertilizer; 25%OF: equal N organic fertilizer replacing 25% chemical N fertilizer; 50%OF: equal N organic fertilizer replacing 50% chemical N fertilizer) and AMF (M+, inoculation of arbuscular mycorrhizal fungi; M-, no inoculation of arbuscular mycorrhizal fungi) was carried out in 2020, with a non-fertilization control (CK). The maize biomass, N accumulation, grain yield, soil inorganic N, and soil N₂O emission flux were measured during maize growth period in both the soil types, and a relative abundance of denitrification functional genes, such as nirK and nirS, was investigated too. 【Result】There was no significant difference in maize grain yield among different OF treatments under the conditions of Shajiang black soil, while grain yield showed decreasing tendency with the OFS ratio increasing in Fluvo-aquic soils. Compared with 0%OF treatment, the cumulative N₂O emissions under 25%OF and 50%OF treatments in Shajiang black soil reduced by 17.6% and 18%, respectively, and by 13.5% and 3.9% in the Fluvo-aquic soil. Compared with non-AMF (M-treatment), the presence of AMF (M+ treatment) increased maize grain nitrate reductase, nitrite reductase, glutamine synthase, glutamate synthase, and maize grain yield, while reduced soil N₂O emissions. The reduction of cumulative N₂O emissions in Shajiang black soil was by 26.5%-28.2%, and by 2.7%-13.5% in Fluvo-aquic soil; the reduction in case of 25% OFM+ treatment was 34.6% and 22.5% in Shajiang black soil and Fluvo-aquic soils respectively, while the root total length, root surface area, root volume and root diameter per plant increased significantly. Correlation analysis showed that N₂O emissions were positively related with soil NH₄⁺ and NO₃^- under both Shajiang black soil and Fluvo-aquic soil conditions, while negatively related with AMF infection rate in both Shajiang black and Fluvo-aquic soils; whereas, the emissions were positively related with the copy numbers of nirK and nirS genes under Shajiang black soil conditions.【Conclusion】The replacing chemical fertilizers with organic fertilizers and inoculation with AMF could reduce N₂O emissions under different soil types. This interactive effect might be the result of expanding root N absorption area through AMF colonization, and by regulating the expression of key functional microorganisms in soil denitrification. Therefore, the study recommends replacement of 25% chemical fertilizer (OF25%) with organic fertilizers and inoculation with AMF could be an ideal fertilizer management method to maintain maize production stable and reduce chemical fertilizer application rate and greenhouse gas emissions.

【Objective】 This study aimed to explore the dynamics of litter decomposition under different environmental precipitation conditions, thereby facilitating understanding of the carbon (C) and nutrient cycling processes and ecosystem functions of steppe ecosystems. 【Method】In this study, soil monoliths selected from three types of temperate steppe along the natural precipitation gradient (i.e. desert, typical, and meadow steppes), and transplanted to conduct a two-year litter decomposition experiment of Cleistogenes squarrosa in typical steppe. We continuously monitored mass loss, the remaining rates of nitrogen (N) and phosphorus (P), as well as the activities of β-glucosidase (BG), leucine aminopeptidase (LAP), N-acetylglucosidase (NAG) and acid phosphatase (AP) during decomposition, to discover the influence of long-term historical precipitation on litter decomposition rate and the dynamic characteristics of decomposition process. 【Result】The litter decomposition rate was highest in the typical steppe with a decomposition constant (k value) of (0.32±0.01) a^-1, were no difference observed between the desert steppe and the meadow steppe. The remaining rate of N and P in litters after two years of decomposition were lowest in typical steppe, with values of (53.0±2.4) % and (58.6±3.9) %, respectively. The N element mainly showed a mineralization pattern during the decomposition stages, while the P was fixed from environment in early stages whereas mineralized in late stages, and microbial P accumulation in litters was greatest in desert steppe. The activities of all enzymes showed fluctuations depending on decomposition stages. Over the whole decomposition time, the activities of C-acquiring enzyme (BG) and N-acquiring enzyme (LAP and NAG) were highest in typical steppe, while the activities of P-acquiring enzyme (AP) were highest in meadow steppe. Combined with the results of enzyme stoichiometry, litter decomposition showed C-limitation in typical steppe, while it was P-limited in meadow steppe. The litter mass loss rate increased with the enhancement of litter BG and NAG activities across the three steppes. 【Conclusion】The mass loss rate, nutrient release rate and enzyme activities of steppe litter did not increase with the increase of precipitation gradient. The litter decomposition fixed more P from environment in water-limited steppe ecosystems. This study reveals the characteristics of litter decomposition process in response to different historical precipitation, advancing our understanding of plant-soil-microbe C and nutrient cycles.

【Objective】 Ammonia volatilization from cropland is one of the main sources of ammonium salts in atmospheric particulate matter, which has a close impact on urban and rural air quality. The temporal-spatial variation characteristics of near-surface atmospheric ammonia concentration and key influencing factors in a typical agricultural area of Henan Province was conducted systematically, so as to provide the scientific basis for targeted management of atmospheric particulate pollutants in cropland areas.【Method】10 typical cropland areas (wheat-maize rotation areas) in Henan Province were selected to conduct a two-year study on monitoring near-surface ammonia concentration by using the ammonia passive method and investigating its driving factors. 【Result】 In terms of time (seasonality), the highest average near-surface ammonia concentration value was found in summer, with an average of 12.0 μg N·m^-3, followed by spring and autumn, with an average of 10.8 and 8.9 μg N·m^-3, respectively, and the lowest value in winter, with an average of only 6.7 μg N·m^-3. From a spatial perspective, the highest ammonia concentration in the cropland area of Zhengzhou in east Henan was 14.7 μg N·m^-3 on average, followed by Xinxiang and Anyang in north Henan with annual average atmospheric ammonia concentrations of 12.5 and 11.0 μg N·m^-3, respectively. Zhengzhou in central Henan and Jiaozuo in north Henan had near-surface atmospheric ammonia concentrations of 10.9 and 10.6 μg N·m^-3, respectively, while the near-surface atmospheric ammonia concentrations in Luoyang, Pingdingshan, Xuchang, Luohe and Zhoukou in west Henan and south Henan were between 7.9 and 9.6 μg N·m^-3. From the perspective of soil types, among which fluvo-aquic soils had the highest near-surface ammonia concentration, with values ranging from 11.0 to 14.7 μg N·m^-3; the ammonia concentration values in the cinnamon soil and yellow cinnamon soil areas ranged from 9.0 to 9.6 μg N·m^-3; the ammonia concentration in lime concretion lime concretion black soil and yellow brown soil cropland was relatively low, with values ranging from 8.06 to 8.11 μg N·m^-3. The high and low near-surface ammonia concentrations in different regions were the result of multiple factors working together. Among them, there was a significant positive correlation between nitrogen fertilizer application rate and soil pH value and near-surface ammonia concentration, while there was a significant negative correlation between rainfall and near-surface ammonia concentration.【Conclusion】Based on the above research results, it was believed that reducing nitrogen application rate could help to systematically reduce the near-surface ammonia concentration in the cropland area of Henan Province, and the cropland area of northern and eastern Henan Province were the key areas of attention.

【Objective】Tea drinks made from Guangdongxiangshui lemon is popular among consumers, but its aroma profile, main aroma-active compounds and corresponding key biosynthesis genes still need to be analyzed. In this study, integrated molecular sensory technology including metabolomics and sensory evaluation was used to explore the material basis and corresponding key genes for the aroma quality of Guangdongxiangshui lemon, aiming at laying a foundation of the citrus aroma quality. 【Method】The volatiles of Guangdongxiangshui lemon from three areas, including Weishan, Yunfu and Wuzhou, were detected via GC-MS, and the aroma quality were evaluated by sensory evaluation panels. The aroma active compounds of Guangdongxiangshui lemon were identified by GC/O-MS combined with aroma extract dilution analysis (AEDA), aroma activity value (OAV) analysis and aroma recombination experiment, and then the characteristic aroma compounds were further identified. Based on gene family analysis, the genes related to aroma formation were illustrated. 【Result】A total of 40, 21 and 33 volatiles were identified in the flavedo, pulp and slices of Guangdongxiangshui lemon, respectively. The samples with the highest volatile content in flavedo and pulp tissues were from Weishan and Yunfu, respectively. In terms of aroma attributes, the aroma intensity of Guangdongxiangshui lemon slices from Weishan and Yunfu was significantly higher than that of Wuzhou. The whole fruit aroma quality of samples from Wuzhou was better than that of samples from other origins. Solvent-assisted flavor evaporation (SAFE) and other methods were used to extract the essential oil of Guangdongxiangshui lemon in Weishan, and 25 aroma active compounds were identified. Combined with OAV analysis and aroma recombination experiments, citronellal and citral were further identified as its characteristic aroma compounds, and the aroma flavor wheel was further constructed. Based on the conserved domain and Blast comparison, 52 terpene synthase (TPS) genes were identified in Guangdongxiangshui lemon genome, which might be involved in the aroma compounds synthesis. 【Conclusion】The volatile spectrum and sensory evaluation showed that the aroma quality of Guangdongxiangshui lemon slices from Weishan were outstanding. A total of 25 aroma active compounds were identified. Among them, citronellal and citral were the characteristic aroma compounds of Guangdongxiangshui lemon, while d-limonene provided a background aroma. Combined with quantitative descriptive analysis and odor note collected via GC/O-MS, the aroma wheel of Guangdongxiangshui lemon was constructed with 15 aroma descriptors in 6 categories, including ‘fruity’ ‘woody’ ‘medicinal’ ‘spicy’ ‘floral’ and ‘grassy’. Furthermore, 52 TPS genes were mined in Guangdongxiangshui lemon genome, which might participate in the aroma compounds synthesis.

【Objective】This study aims to investigate the role of the grape autophagy gene ATG8f in regulating copper stress tolerance in plants, thereby laying the foundation for elucidating copper tolerance mechanisms and constructing regulatory networks. 【Method】Based on multi-omics sequencing analysis of Shine Muscat grapevine under copper stress, the autophagy gene VlATG8f was identified and its sequence characteristics were analyzed. The CDS sequence of VlATG8f was cloned and an overexpression vector was constructed. The subcellular localization of the VlATG8f protein was studied through transient expression in tobacco. Heterologous expression of VlATG8f in Arabidopsis was achieved using the floral dip method. Seed germination rate and root length were measured to compare the growth and development of wild-type and transgenic lines under copper stress. Real-time quantitative PCR was used to analyze the expression levels of related antioxidant genes, and yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays were used to preliminarily screen for VlATG8f- interacting proteins. 【Result】The CDS of VlATG8f was 393 bp, encoding 130 amino acids. Bioinformatics analysis revealed that the ATG8f protein sequences in Arabidopsis, tomato, apple, pear, peach, and grapevine were relatively conserved, all containing a Ubl_ATG8 conserved domain, indicating potential functional were conserved. Subcellular localization showed that the VlATG8f protein was located on both the nucleus and cell membrane. Under normal conditions, both wild-type and VlATG8f-overexpressing lines exhibited healthy growth with green leaves. Under copper stress, the transgenic lines were less stunted and exhibited milder symptoms of chlorosis, leaf curling, reduced root hair size, and increased lateral roots compared to wild-type plants. Overexpression of VlATG8f in Arabidopsis resulted in less growth inhibition under copper stress, higher seed germination rate, longer root, and lower accumulation of hydrogen peroxide (H₂O₂), indicating enhanced copper tolerance. Additionally, the expression of antioxidant genes AtCSD1 and AtCCS1 increased in VlATG8f-overexpressing plants under copper stress, while the expression of the key ROS synthesis gene RbohB decreased, promoting ROS scavenging. Yeast two-hybrid screening identified 23 potential interacting proteins with VlATG8f. BiFC further confirmed strong interactions between VlATG8f and proteins such as PYL8, MnSOD, AUX22D, bZIP17, and COT44. 【Conclusion】Overexpression of VlATG8f may enhance copper tolerance in transgenic lines by strengthening the antioxidant system, reducing ROS synthesis, and promoting the synthesis of plant hormones, thereby mitigating copper toxicity in plants.

【Objective】This research studied the effects of alcalase hydrolysis on the structure, physicochemical properties and aggregation behavior of quinoa protein isolate (QPI), and explored its effects on the gelling properties of QPI. 【Method】QPI was extracted by alkaline extraction and acid precipitation method at 4 ℃. Alcalase with different enzyme-substrate ratios was added to the QPI solution to hydrolyze the protein. Thereafter, the changes of the composition, particle size, Zeta potential, solubility, and surface hydrophobicity (S₀-ANS) of QPI were analyzed, and the correlation between these changes and the Th T fluorescence intensity and morphology of protein thermal aggregates were discussed. Furthermore, the concentration of QPI dispersion was elevated to form heat-induced QPI gels. The correlation among alcalase hydrolysis, aggregation behavior and gelling properties of QPI was discussed through the analysis of the microstructure, texture and protein secondary structure of QPI gels. Meanwhile, the reasons for the changes in the gelling properties of QPI induced by alcalase hydrolysis were revealed.【Result】With the increase of enzyme substrate ratio (E/S), the protein particle size of QPI dispersion (2%, w/v) gradually decreased, and its electronegativity increased first and then decreased. Meanwhile, the surface hydrophobicity of QPI gradually increased as the E/S increased. At the same time, the Th T fluorescence intensity of QPI aggregates showed an upward trend as E/S rose from 0 to 0.08%, and then declined when the E/S further increased to 0.14%. Through TEM observation, short fibrils (145-306 nm) and long fibrils (217-406 nm) were formed when E/S was 0.05% and 0.08%, respectively. However, with the further increase of E/S ratio, the length of fibrils became shorter, and more amorphous aggregates appeared. In addition, it was found that the aggregation behavior of QPI had a significant effect on its gelling properties (P<0.05). QPI gels showed enhanced hardness, higher storage modulus and a denser network structure, when fibrillar aggregation was dominant. Compared with short fibrils, long fibrils exerted a more significant effect to improve the gelling properties. Furthermore, alcalase showed a significant effect on the protein secondary structure of QPI gels, and the contents of β-sheet and random coil rose first and then decreased with the increase of E/S.【Conclusion】The limited alcalase hydrolysis promoted QPI to form ordered fibrillar aggregates, and further improved its gelling properties. When the E/S was 0.08%, QPI formed the longest fibrils, and QPI gels exhibited the highest hardness as well as the most favorable viscoelastic properties. Meanwhile, the protein secondary structure of QPI gels was ordered, and their microstructure was dense. However, the higher degree of hydrolysis was unfavorable to form fibrillar aggregates and failed to improve the gelling properties. Therefore, limited alcalase hydrolysis could significantly improve the weak gelling properties of QPI through fibrillation.

【Background】 H5, H7 and H9 subtypes of avian influenza viruses (AIV) and Newcastle disease virus (NDV) are important pathogens that seriously jeopardize the avian industry, and vaccination with inactivated vaccines in the form of oil emulsions is the mainstay of prevention of avian influenza and Newcastle disease. At present, more than two vaccines are needed to prevent these infectious diseases in poultry farms, which leads to more times of vaccination and heavy immune burden on poultry. In addition, the mineral oil used to produce oil-emulsion inactivated vaccines is mainly dependent on imports, which has the risk of “neck sticking”. 【Objective】In order to reduce the number of vaccinations, lower the burden of immunization, and compare the effects of domestic and imported mineral oil adjuvants, this study developed and evaluated the inactivated vaccines, which could simultaneously prevent avian influenza (H5+H7+H9) and Newcastle disease by using different mineral oil adjuvants. This study expected to achieve the immunization effect of “one immunization preventing multiple diseases” and provide data support for the localization of mineral adjuvants for animal vaccines.【Method】A total of five vaccine strains of avian influenza H5-Re13, H5-Re14, H7-Re4, H9-GX11583 and Newcastle disease ND rLa-VII strains that have been constructed in the laboratory, which were inoculated into chicken embryos, harvested the allantoic fluid, concentrated and inactivated. Different mineral oil adjuvants (Total, Marcol 52 and HTM70) were added at a ratio of 1 part antigen to 3 parts of adjuvant. The mixture was then thoroughly mixed and emulsified to prepare the combined inactivated vaccine. Finally, the safety and efficacy of the vaccine were evaluated through intramuscular injection on three-week-old SPF chickens using doses of 2 mL and 0.5 mL, respectively.【Result】The results of the immunity efficacy test showed that the three kinds of mineral oil adjuvanted dichotomous multivalent inactivated vaccines had good safety for chickens; all three mineral oil adjuvanted vaccines could produce effective HI antibodies against H5-Re13, H5-Re14, H7-Re4, H9-GX11583 and ND rLa-VII strains after inoculation of chickens, and could obtain complete immune protection against the attack of the efficacy test strains. The results of HI antibody duration showed that all three mineral oil adjuvant inactivated vaccines could continuously induce high level of antibodies for more than half a year, compared with imported mineral oils (Total, Marcol 52), the level of HI antibody induced by domestic mineral oil HTM70 was close to that of imported mineral oil Total and higher than that of imported mineral oil Marcol 52, but the domestic mineral oil adjuvant HTM70 had no significant difference between batches.【Conclusion】The combined inactivated vaccine against avian influenza (H5+H7+H9) and Newcastle disease prepared in this study had a good immune efficacy on SPF chickens, and the domestic substitution of mineral oil adjuvant was expected.

【Background】Salmonella is an important zoonotic pathogen and foodborne pathogen, with over 2 600 identified so far. Different serotypes of Salmonella exhibits varying degrees of pathogenicity to animals and humans. Broiler is one of the important hosts of Salmonella epidemic transmission, and its contamination status is directly related to the healthy breeding of broilers and public health security. The broiler production chain is the main source of Salmonella infection in broilers, which mainly covers breeder farms, broiler hatcheries, and broiler farms, etc. The study of the prevalence and transmission of Salmonella in different production links of broilers is of great significance for the prevention and control of Salmonella in broilers and for public health and safety. It is important to study the prevalence and transmission of Salmonella in different links of broiler production for the prevention and control of Salmonella in broiler and public health safety.【Objective】 This study systematically investigated the prevalence, serotype distribution and molecular typing of Salmonella in different production chains of broilers, taking broiler breeder farms, broiler hatcheries and commercial broiler farms in the Beijing-Tianjin-Hebei region as an entry point, which provided data for the study of Salmonella epidemic and transmission in broiler production chain.【Method】A total of 2 572 samples were collected from 28 broiler farms in different production stages of broilers in the Beijing-Tianjin-Hebei region (including within a certain breeding group), of which 324, 747 and 1 501 samples were collected from broiler breeder farms, broiler hatcheries and commercial broiler farms, respectively. Firstly, the samples were cultured for the enrichment of Salmonella, and then the isolation and identification of Salmonella were carried out by color development medium and Polymerase Chain Reaction (PCR); secondly, the identified Salmonella were serotyped by Danish serum, and the identification of Salmonella was carried out by Pulsed Field Gel Electrophoresis (PFG), and the identification of Salmonella was carried out by PFG, and the identification of Salmonella was carried out by PFG. The results were analyzed by Pulsed Field Gel Electrophoresis (PFGE) method for molecular typing of Salmonella. Finally, the carrier status, serotype distribution and molecular typing results of broilers from different production farms were analyzed and compared.【Result】A total of 335 strains of Salmonella were isolated from different production segments of broilers, with an overall isolation rate of 13.0%, of which the isolation rates of Salmonella from broiler breeder farms, broiler hatcheries and commercial broiler farms were 3.4%, 30.3% and 6.5% respectively. A total of 32 Salmonella strains were isolated from different production segments within the same farming group, with an isolation rate of 8.6%, among which the isolation rates of Salmonella from broiler breeder farms, broiler hatcheries and commercial broiler farms were 2.0%, 14.0% and 9.2%, respectively. A total of 11 serotypes of Salmonella isolates were distributed, with the dominant serotype was S. enteritidis, followed by S. tennessee, S. gallinarum and S. javiana. There were differences in the dominant serovars of Salmonella in different production stages of broiler chickens, including S. enteritidis and S. nitra in broiler breeder farms; S. enteritidis, S. tennessee, and S. gallinarum in broiler hatcheries; and S. enteritidis, S. javiana, and S. gallinarum in commercial broiler farms. Except for five strains of S. eschweiler isolated from feed, all Salmonella serotypes isolated from different production segments within the same farming group were S. enteritidis. The PFGE typing results of Salmonella isolates from different production segments of broiler chickens showed that the PFGE homology of Salmonella from different serotypes was low; the PFGE band spectra of most S. enteritidis belonged to clustering group I, with a degree of similarity of 93.1%; and there were identical PFGE spectra of S. enteritidis isolated from different production segments in the same breeding group.【Conclusion】The isolation rate of Salmonella in various production segments of broiler in Beijing-Tianjin-Hebei region varies greatly, mainly dominated by the epidemic transmission of S. enteritidis, and there is vertical clonal transmission of S. enteritidis between different production links of broilers; breeders are an important source of Salmonella infection in broilers, the environment of the farms and feeds are also one of the sources of Salmonella infections in broilers.Therefore, it is necessary to strengthen the purification of Salmonella in breeder chickens, and at the same time to do a good job in the prevention and control of Salmonella in other production links, in order to guarantee the healthy breeding of broiler chickens and the security of public hygiene.

【Objective】The objective of this study is to optimize the classification and discriminant method of maize heterotic groups, and provide guidance and reference for maize breeding practices.【Method】Solid-phase chips were used to genotype 60 waxy maize inbred lines, and high-quality SNP markers with different density were obtained through quality control. Population structure analysis and genetic distance clustering were used to classify the 60 waxy maize inbred lines into different groups, and the differences between different classification methods were compared. On this basis, random forest and support vector machine methods were used to sample and discriminate the results of different classification methods. Five-fold cross-validation was used for sampling, and the prediction accuracy of maize group classification based on different classification methods was compared.【Result】Using different quality control standards, 11 431 and 4 022 molecular markers were obtained, respectively. Based on these two molecular marker densities, 60 materials were divided into 5 and 4 clusters, respectively. When using 11 431 SNP markers, the population structure analysis and genetic distance clustering results showed that the intra-cluster sample consistency was 63.33%. When using 4 022 SNP markers for clustering, the intra-cluster sample consistency was 90.00%. The prediction accuracy results for discriminating maize inbred line clusters showed that the average prediction accuracy (91.43%) of Random Forest and Support Vector Machine using 4 022 markers were higher than that of 11 431 markers (86.25%). Among them, the highest prediction accuracy was achieved by Random Forest using 4 022 markers, with a prediction accuracy of 94.17%.【Conclusion】Clustering analysis ultimately divided 60 waxy maize inbred lines into 4 clusters. Sampling and cross-validation results using Random Forest and Support Vector Machine for cluster classification showed that Random Forest achieved higher prediction accuracy than Support Vector Machine.

【Objective】Seeking key indicators and methods for accurately characterize drought tolerance in sweet potato, and screening and identifying drought-tolerant sweet potato germplasm resources, to provide effective methods for the rapid and accurate identification of drought-tolerant sweet potato germplasm resources, and to provide material and theoretical basis for selection and breeding of high quality and drought-tolerant sweet potato varieties. 【Method】Fifty-four sweet potato germplasm resources were used as materials for drought stress experiments. By using two treatments including drought stress and control, and combining with drought pool cultivation experiment and field test, the effects of drought stress on the growth and development, physiological and biochemical characteristics, antioxidant metabolism, photosynthetic characteristics and yield of different sweet potato germplasm resources were investigated, the response characteristics of different sweet potato germplasm resources to drought were analyzed, and the effective indicators for drought tolerance evaluation in sweet potato were selected. The drought tolerance evaluation was preformed using principal component analysis, correlation analysis, direct evaluation of drought resistance coefficient, and calculation of comprehensive drought tolerance measurement value (D value) based on membership function, and the drought-tolerant sweet potato germplasm resources were screened and identified.【Result】The results obtained from the drought pool cultivation experiment showed the influences of drought treatment on the main stem length, aboveground fresh weight, underground dry weight and fresh weight of storage root were extremely significant (P<0.01), and eight drought-tolerant germplasm resources were screened based on cluster analysis of D values. In the field test, the main stem length, stem diameter, number of branches, leaf area index, leaf relative water content, total chlorophyll content, stomatal conductance, net photosynthetic rate, transpiration rate, intercellular carbon dioxide concentration, proline (Pro), malondialdehyde (MAD), peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) showed highly significant differences (P<0.01) under drought stress when compared with control. Through the establishment of regression models, it could be initially determined that eight indicators including the leaf area index, root tip, leaf POD, leaf APX, storage root Pro, storage root SOD, storage root CAT, and yield could be used as indicators for drought tolerance identification in sweet potato. XN18111-1, 20XN18-1, XN1834-11 and XN17104-46 were classified as drought-tolerant germplasm resources according to grading of drought resistance coefficient based on yield. The D values of XN18111-1, 20XN18-1 and XN1862-61 were over 0.6 and showed high drought tolerance based on comprehensive drought tolerance evaluation. 【Conclusion】Based on results of comprehensive drought tolerance evaluation in drought pool cultivation experiment, as well as the comprehensive drought tolerance evaluation and yield evaluation in field test, XN18111-1 and 20XN18-1 were finally identified as drought-tolerant germplasm resources, which can be used as drought-tolerant breeding materials or ideal resource materials for study on drought-tolerance mechanism in sweet potato.

【Objective】Based on the long-term experiment in the North China Plain (NCP), the differences in soil nutrient and aggregate nutrient distribution between diversified crops and wheat-maize rotation systems were investigated. Additionally, it provided a comprehensive evaluation of soil quality indices (SQI), offering a scientific basis for enhancing soil quality and productivity in the NCP. 【Method】Four diversified crop rotation systems were evaluated, including spring sweet potato-winter wheat-summer maize (Psw-WM), spring peanut-winter wheat-summer maize (Pns-WM), spring sorghum-winter wheat-summer maize (Ps-WM), with winter wheat-summer maize (WM-WM) serving as the control. The soil samples from the 0-40 cm depth were collected during the second rotation in 2022, at the flowering and harvesting stages of winter wheat. The soil enzymes activities, aggregate stability, organic matter, and concentrations of nitrogen, phosphorus, and potassium in soil and aggregates of different sizes (>2.00 mm, 0.50-2.00 mm, 0.25-0.50 mm, and <0.25 mm) were assessed. The SQI for each crop rotation system was then comprehensively evaluated. 【Result】Compared with WM-WM, the three other crop rotations increased soil inorganic nitrogen content. Psw-WM significantly enhanced organic matter in the 0-20 cm layer, total nitrogen in soil aggregates (>2.00 mm, 0-10 cm), and organic matter in soil aggregates (>2.00 mm and 0.50-2.00 mm, 0-10 cm), which also increased cellulase, catalase, and alkaline protease activities. Pns-WM improved organic matter in the 20-40 cm layer and available potassium in soil aggregates (0.25-0.50 mm and >2.00 mm, 10-20 cm), as well as organic matter in soil aggregates (0-10 cm, >2.00 mm and 10-20 cm, >0.50 mm), which also increased sucrase, urease, and alkaline protease activities. Psw-WM improved the stability of 0-10 cm soil aggregates, while Pns-WM improved the stability of 0-30 cm soil aggregates. Both Pns-WM and Psw-WM significantly improved the SQI, with Pns-WM showing a higher improvement than Psw-WM. The path analysis revealed that the average weight diameter (MWD) of aggregates was a direct and significant affecting SQI. It also had a significant indirect positive effect on SQI by influencing inorganic nitrogen. Additionally, the increased organic matter led to a higher proportion of large aggregates, which significantly affected SQI indirectly. 【Conclusion】Legume (peanut) and root crop (sweet potato) rotations with wheat-maize rotations could significantly improve soil quality and enhance the soil nutrient supply capacity in the NCP.

【Objective】Nitrogen is one of the essential nutrients for plant growth and development, and it plays an important role in strengthening chlorophyll synthesis in crops, enhancing plant resistance, and improving yield and quality. This study harnessed hyperspectral technology to swiftly, precisely, and non-invasively monitor nitrogen levels in pepper foliage throughout its growth cycle, delving into the correlation between leaf nitrogen content (LNC) and spectral reflectance characteristics. 【Method】The study was based on the hyperspectral data of pepper leaves collected from Guanzhuang Demonstration Base in Pepper Research Institute of Guizhou Academy of Agricultural Sciences in 2021. The research encompassed four pepper varieties (Qianjiao No. 8, Hongla No. 18, Layan 101, and Hong Global) and five different nitrogen fertilizer application rates (0, 120, 240, 360, and 480 kg·hm^-2). The pepper leaf spectral data were processed, involving Multiple Scatter Correction (MSC), Savitzky-Golay (SG) and First Derivative (FD), followed by the selection of sensitive bands using Pearson correlation coefficient, Successive Projections Algorithm (SPA) and Competitive Adaptive Reweighted Sampling (CARS). Subsequently, three machine learning algorithms, such as Partial Least Squares Regression (PLSR), Random Forest (RF) and Radial Basis Function Neural Network (RBFNN), were employed to construct models for monitoring nitrogen levels in pepper leaves, to achieve the goals of enhancing agricultural production efficiency and accuracy, and realizing intelligent management and precise fertilization. 【Result】After preprocessing, the original spectra improved correlation coefficients significantly. Among these, the spectral data's inversion performance was notably superior after SG processing, with the effectiveness ranking as SG>FD>MSC>original spectra. Contrasting various band selection methods, the employing Pearson correlation coefficient for band selection resulted in bands being overly concentrated, leading to either redundant information or incomplete information extraction. While CARS algorithm selected bands across a broad range and in large quantities, its effectiveness was inferior to SPA due to containing more redundant information and noise. SPA-selected nitrogen content characteristic bands effectively reduced collinearity and redundant information, yielding the optimal model with the highest R² and the smallest RMSE. The performance of different modeling methods for pepper LNC estimation was as follows: RBFNN performed the best, followed by PLSR, with RF exhibiting the poorest performance. Among these, the SG-SPA-RBFNN combined model demonstrated the best inversion accuracy, with modeling results of R² =0.98 and RMSE =0.62, and validation results of R² =0.98 and RMSE =1.21, with an RPD of 3.08. RBFNN model excelled in handling high-dimensional spectral data, surpassing traditional PLSR and RF models. 【Conclusion】The hyperspectral reflectance characteristics were utilized to establish nitrogen content prediction models, which could effectively monitor nitrogen levels in pepper leaves, thereby enhancing agricultural management efficiency and providing the technical support for precise management and variable fertilization in pepper cultivation.

【Objective】Macro-transcriptome sequencing and small RNA sequencing are commonly used high-throughput sequencing techniques in virus identification. The objective of this study is to explore the application efficiency of macro-transcriptome sequencing and small RNA sequencing in the identification of emerging viruses in apples, analyze the impact of different tissue types on the identification results, and to provide a basis for the accurate diagnosis of apple virus diseases.【Method】The samples of apple peel and branch bark were collected from ‘Luli’ apple trees exhibiting novel viral symptoms in Shenzhou County of Hengshui City in August 2022. Total RNA was extracted, and macro-transcriptome libraries and small RNA libraries were constructed for high-throughput sequencing. Bioinformatic techniques and software were utilized to analyze and evaluate the sequencing data. Initially, the indicators from the high-throughput sequencing technique results were compared. Subsequently, a comprehensive evaluation of the effectiveness of each sequencing method was conducted using the analytic hierarchy process (AHP) and a 5-level grading system to calculate the weighted values of these indicators. Finally, RT-PCR was employed to validate the high-throughput sequencing results, and the genomic characteristics and phylogenetic relationships of the emerging viruses were analyzed.【Result】In terms of splicing effect, using the same tissue material, the macro-transcriptome sequencing outperformed small RNA sequencing. When the same technique was applied, the splicing effect for fruit peel tissue was better than that of branch bark. In terms of the number of virus species detected, macro-transcriptome sequencing identified the highest number of virus species in branch bark, including eight viruses: apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple necrotic mosaic virus (ApNMV), apple rubbery wood virus 2 (ARWV-2), apple green crinkle associated virus (AGCaV), citrus concave gum-associated virus (CCGaV), and citrus tatter leaf virus (CTLV). In contrast, small RNA sequencing technique detected the fewest virus types in branch bark. There were differences in virus types between fruit peels and branch barks detected through small RNA sequencing technique. When fruit peels were used as the detection target, both methods identified the same number of virus types. After comprehensively comparing the synthesis score of various indicators, the macro-transcriptome sequencing of bark samples scored the highest. The results of high-throughput sequencing were consistent with those obtained through RT-PCR. ARWV-2 and CCGaV were discovered for the first time in Hebei Province, and were designated as ARWV-2-HB and CCGaV-HB. The GenBank accession numbers for the coat protein (CP) gene of ARWV-2-HB and the movement protein (MP) and CP genes of CCGaV-HB are PQ095583, PQ095581, and PQ095582. The genomic sequences of both viruses showed over 96% identity to their respective representative isolates. Phylogenetic trees constructed based on the CP amino acid sequences of ARWV-2 and CCGaV revealed that ARWV-2-HB was most closely related to LYXS (MZ819711), while CCGaV-HB exhibited relatively close relationships with Mishima (MK940543), Gala (MK940542), Gala-BJ (OP820577), Fuji-BJ (OP556109), and AC1 (MH038043).【Conclusion】Using macro-transcriptome sequencing and small RNA sequencing techniques, the fruit peel and branch bark of the same ‘Luli’ apple tree were sequenced separately. Among two sequencing methods, the macro-transcriptome sequencing of branch bark showed the best sequencing effect, discovered the highest number of viruses and relatively complete viral genome sequences. When using small RNA sequencing, only a portion of virus types could be detected in both fruit peels and branch barks. Due to the differences in virus types detected from different tissue materials, it is recommended to test both tissue materials simultaneously. ARWV-2 and CCGaV were reported in Hebei Province in this study, and partial genomic sequences of ARWV-2-HB and CCGaV-HB were revealed, which enriching the genomic sequence information of ARWV-2 and CCGaV. Furthermore, the phylogenetic relationships of these two viruses with other representative isolates have been clarified.

【Objective】Mucin-like proteins are integral to the formation of salivary sheaths in Hemiptera insects. This research seeks to prepare a specific antibody targeting the Diaphorina citri mucin-like protein (DcMucin-like) and to employ immunofluorescent labeling to identify the feeding sites of D. citri, so as to provide a basis for the study of the biological functions of DcMucin-like.【Method】The salivary glands, midgut, ovaries, and testes of D. citri were dissected for analysis. Specific primers were designed based on the DcMucin-like sequence of the psyllid, and real-time fluorescent quantitative PCR was employed to assess the transcriptional level differences of DcMucin-like across various tissues. The DcMucin-like sequence, excluding the signal peptide, was amplified and subsequently inserted into the pET-28a vector to construct a recombinant plasmid. Following sequence verification, the plasmid was transformed into Rosetta expression strains. The expression of recombinant protein was induced using 0.5 mmol·L^-1 IPTG at 37 ℃ with agitation for 8 h. The presence of the recombinant protein was confirmed via SDS-PAGE gel electrophoresis. Following large-scale bacterial culture, the cells were lysed, and the supernatant was subjected to purify using Ni-NTA affinity chromatography to obtain the antigen. This antigen was subsequently used to immunize rabbits five times. The resulting purified serum IgG yielded the DcMucin-like polyclonal antibody, whose specificity was assessed through Western blot analysis. Real-time fluorescent quantitative PCR and Western blot analyses were employed to compare the transcriptional and protein expression levels of DcMucin-like between healthy and Candidatus Liberibacter asiaticus (CLas) infected D. citri. The feeding sites of D. citri on citrus leaves post-ingestion were labeled using DcMucin-like polyclonal antibodies conjugated with fluorescein isothiocyanate (FITC). These feeding sites, along with the salivary sheaths of D. citri, were subsequently examined under a confocal microscope.【Result】Real-time fluorescent quantitative PCR analysis revealed that the DcMucin-like exhibited significantly elevated expression level in the salivary gland of D. citri compared to the midgut, ovary, and testis. Rosetta expression strains harboring the pET28a-DcMucin were induced with IPTG, resulting in the production of substantial quantities of recombinant protein in the supernatant of the bacterial lysate. The recombinant protein was utilized to immunize rabbits for the production of antiserum, from which purified IgG was subsequently employed to generate DcMucin-like polyclonal antibodies. Western blot analysis confirmed the successful acquisition of specific DcMucin-like polyclonal antibodies. Furthermore, DcMucin-like expression was found to be upregulated in D. citri response to CLas infection. The DcMucin-like (FITC) fluorescent antibody-labeled tissue sections of citrus leaves, following D. citri feeding, were examined using a confocal microscope. Specific FITC fluorescence signals were detected in proximity to the feeding sites, suggesting that DcMucin-like was released into plant tissues during D. citri feeding to participate in the formation of salivary sheaths.【Conclusion】DcMucin-like is highly expressed in the salivary glands of D. citri and exhibits upregulation in response to CLas infection. Specific polyclonal antibodies targeting the DcMucin-like salivary protein of D. citri were successfully generated, demonstrating high specificity. Additionally, it was confirmed that DcMucin-like was secreted into citrus plant tissues during D. citri feeding. These findings provide a foundational basis for further investigation into the role of DcMucin-like in the interactions among CLas, D. citri, and citrus plants.

【Objective】 This study was to clarify differences of zinc (Zn) concentration in wheat grain and flour and the corresponding affecting factors over major wheat production regions, with the purpose to provide the theoretical basis for improving the Zn nutritional quality of wheat grain in China. 【Method】During 2020-2021 and 2021-2022 wheat growing seasons, 421 wheat and soil samples were collected from major wheat production regions in 17 provinces and autonomous regions of China, to explore the relationship of Zn concentration in wheat grain, flour and bran with wheat yield, yield components and soil properties.【Result】The average Zn concentration of the wheat grain, flour and bran was 28.1, 10.8 and 60.6 mg·kg^-1, respectively, with 94.8% of grain and 89.5% of flour samples could not meet with the recommended Zn concentration of 40 mg·kg^-1 for grain and 15 mg·kg^-1 for flour by nutritionists. The highest grain Zn concentration was observed in rice-wheat region (RW), followed by that in wheat-maize regions (MW) and dryland wheat region (DW), and the lowest was in spring-wheat region (SW). In rice-wheat region, the lower pH promoted the activation of soil Zn, and its availability was significantly higher than that in other regions, the lowered phosphorus fertilizer application rate was also conducive to Zn absorption and its translocation from root to the aboveground, and the average Zn concentration in wheat grains and flour was therefore as high as 31.5 and 12.2 mg·kg^-1, respectively. In wheat-maize region, the soil fertility was higher, so that the yield was significantly greater than that in other wheat regions, resulting in relatively lower Zn concentrations in wheat grains and flour, which were 27.1 and 10.3 mg·kg^-1, respectively. In dryland wheat region, the higher soil pH limited soil Zn availability and wheat Zn absorption, leading to the grain and flour Zn concentration being relatively lower as 26.5 and 10.1 mg·kg^-1, respectively. In spring-wheat region, since the soil available Zn concentration was significantly lower than that in other wheat regions, which was not conducive to Zn absorption by wheat and its accumulation in grain, and therefore the Zn concentrations in grain and flour were the lowest as 24.6 and 9.4 mg·kg^-1, respectively, while Zn concentration decreased significantly with the increase of 1000-grain weight.【Conclusion】 Therefore, in order to improve the Zn concentration of wheat grains and flour, it was not only necessary to improve the soil pH, available Zn level and reasonable nitrogen and phosphorus fertilizer application, but also jointly to optimize the yield components to improve the wheat yield and grain and flour Zn concentration.

【Objective】This experiment was conducted to investigate the optical properties of dissolved organic matter (DOM) and the intrinsic relationship with soil microbial communities diversity and structure under long-term application of fresh and composted chicken/pig manure, so as to provide a theoretical reference of soil ecology for the implementation of recycling agriculture in the red soil area.【Method】Based on an 11-year (2011-2022) long-term experiment (sweet corn-sweet corn-cabbage rotation) of the National Soil Quality Guangzhou Red Soil Observatory Experiment Station, the fertilization regimes included no manure, chicken manure organic fertilizer, fresh chicken manure, fresh pig manure organic fertilizer, and fresh pig manure. Surface soil samples were collected and subjected to soil chemical properties determination, DOM UV-absorption characterization, parallel factor analysis of DOM fluorescence absorption characteristics, and Illumina MiSeq high-throughput sequencing, respectively. The main influencing factors were analyzed based on multivariate analysis.【Result】The composted manure significantly increased soil organic matter (122.5%-354.8%) and nutrient content, among which the chicken manure source treatments effectively increased soil available phosphorus content (1 697.2%-3 455.3%) and total phosphorus content (587.5%-812.5%), while swine manure source treatments mainly increased soil alkali-hydro nitrogen content (286.6%-311.3%) and total nitrogen content (326.4%-373.6%). Livestock manure applications, especially the composted manure, increased soil DOM content (60.3%-227.8%), among which the swine manure source treatments had a better effect on chromophoric dissolved organic matter content (118.1%-231.7%). In contrast, the chicken manure source treatments focused on increasing soil fluorescent dissolved organic matter (FDOM) content (293.4%-834.9%). For FDOM characteristic indexes, the biological index of manure application treatments was lower than that under CK (33.2%-39.2%), but the humification index was higher than that under CK (40.3%-43.3%). Four fluorescence components were identified with parallel factor analysis. The manure applications treatments mainly enriched the C3 (medium-size humus molecule containing fulvic acid and humic acid) and C4 (large-size humus molecule containing tryptophan) components, which promoted the conversion of protein-like components into humus-like components in FDOM. The maximum fluorescence intensities of the C3 and C4 components were higher in composted manure treatments. The composted chicken manure was more advantageous in increasing microbial community α-diversity, for the soil microbial community richness (Chao 1 index:19 065.6) and diversity (Shannon index: 5.6-6.0) were higher. The microbial community structures vary according to different treatments. The chicken manure source treatments were dominated by the eutrophic taxa Proteobacteria (31.2%-33.0%) and Gemmatimonadetes (4.1%), while the swine manure source treatments were dominated by the oligotrophic and efficient carbon-utilizing taxa Acidobacteria (21.0%-21.6%) and the nitrifying bacterial taxa Nitrospirae (2.6%-3.4%). Positive correlations dominated the co-occurrence networks, and Rhodobacteraceae had the highest number of correlations with other microbes. Redundancy Analysis and optimized random forest model showed that microbial communities were mainly influenced by available potassium and the C3 component of DOM, with a more pronounced response from nitrogen cycle-related microbial groups.【Conclusion】Long-term application of different manure sources mainly led to differences in humic components mediated by nutrients and organic matter input. Composted manure treatments improved the soil organic matter content and the degree of DOM humification. The available nutrients in soil and the humic-like components of DOM were the main factors affecting the structure of the soil microbial community. The response of nitrogen cycle-related microbial groups to these factors was particularly obvious and should be paid attention under long-term application of manure.

【Objective】This study aims to explore the molecular mechanisms underlying the formation of Non-red ground color in Xinjiang local peach (Prunus ferganensis and P. persica), providing a theoretical basis for the breeding of new peach varieties with Non-red skin color. 【Method】A phenotypic survey of the skin color of 85 progenies of Xinjiang peach and three cultivated varieties was conducted. The activity of various lengths of the PpMYB10.1 promoter was assessed using β-glucuronidase (GUS) staining. Predictive analysis of the cis-acting elements of the PpMYB10.1 promoter from different materials was performed using the PlantCARE (https://bioinformatics.psb.ugent.be/webtools/plantcare/html/). Genotypes with a 5 243 base pairs (bp) transposon insertion and a 483 bp deletion in the PpMYB10.1 promoter of 88 materials were identified and cloned using polymerase chain reaction (PCR). The transcriptional activation of PpMYB10.1 by Pp.4G186800 was validated through dual-luciferase assays. 【Result】Based on skin color, 85 Xinjiang peach progenies were classified into Non-red and red types. The majority exhibited Non-red colors (green or light yellow) with minimal or no anthocyanin accumulation. Compared to the fully red variety Zhongtao Jinmi, these exhibited significantly lower levels of anthocyanins and reduced expression of PpMYB10.1. Using GUS staining to assess the effects of promoter mutations on activity, the results showed that a 5 243 bp insertion in the PpMYB10.1 promoter caused the fruit discs to display a lighter blue, indicating decreased activity. Conversely, a 483 bp deletion resulted in a darker blue, suggesting increased promoter activity. No such insertions or deletions were found in the PpMYB10.1 promoter of the Xinjiang peach progenies. The promoter sequences of PpMYB10.1 were cloned, and cis-acting elements were categorized into four groups: light-responsive, plant hormone-responsive, abiotic stress and growth development-responsive, and elements of unknown function. Due to the late maturation of the Xinjiang peach progenies, all were found to have a 0 bp/0 bp genotype for the maturity-regulating gene Pp.4G186800. Dual-luciferase assays showed that Pp.4G186800 could bind to the PpMYB10.1 promoter. Notably, when the promoter had a 483 bp deletion, Pp.4G186800 (+9 bp) formed a strong interaction, potentially enhancing early maturation and anthocyanin accumulation in the peach skin. However, in late-ripening peaches, Pp.4G186800 (-9 bp) had no enhancing effect on the promoter’s activity; If the PpMYB10.1 promoter lacked the 483 bp deletion, its intrinsic activity was weak, even though Pp.4G186800 could still interact with it, the effect was minimal.【Conclusion】The presence of insertions and deletions in the PpMYB10.1 promoter is not directly related to the Non-red skin color of Xinjiang peach. In early and mid-ripening varieties, Pp.4G186800 can activate the transcription of PpMYB10.1, facilitating anthocyanin synthesis; however, its influence is reduced or absent in late-ripening peaches.

【Objective】To investigate the variation patterns of phenotypic traits and their relationship to genetic diversity in Cymbidium faberi germplasm, to explore reliable comprehensive evaluation methods for germplasm resources, to screen for superior germplasm, and to provide a critical basis for germplasm innovation and new cultivar breeding in Cymbidium faberi Germplasm. 【Method】Using 102 C. faberi germplasm samples, 38 phenotypic traits were measured. Multiple statistical methods were employed, including the genetic diversity index, principal component analysis (PCA) combined with membership function method, cluster analysis, and correlation analysis, to perform phenotypic genetic diversity analysis and a comprehensive evaluation of the germplasm. Superior C. faberi germplasm was screened based on the comprehensive evaluation F-value and target traits.【Result】The coefficient of variation for quantitative traits in the 102 C. faberi germplasm samples ranged from 13.18% to 28.28%, and the genetic diversity index ranged from 1.52 to 1.97, with higher indices observed for traits such as the number of flowers and sepal shape. Significant or highly significant correlations were found among 46 pairs of traits, with most vegetative organ traits showing a highly significant positive correlation with reproductive organ traits. PCA results indicated that 12 principal components were extracted when the cumulative contribution rate of phenotypic traits reached 74.52%. The comprehensive evaluation F values calculated using the membership function method ranged from -0.45 to 1.26, identifying the top 10 superior C. faberi germplasm resources. Systematic clustering grouped the phenotypic traits and germplasm resources into three categories. R-type clustering visually displayed the associations between different quantitative and qualitative traits, consistent with the correlation analysis results. Q-type clustering revealed the phylogenetic relationships and genetic backgrounds among different C. faberi germplasm; 9 of the top 10 germplasm resources based on the comprehensive evaluation F-value were in the third major category. 【Conclusion】C. faberi germplasm exhibits rich diversity in both quantitative and qualitative traits. Utilization of multivariate statistical analysis methods for comprehensively evaluating C. faberi is feasible. The combination of the membership function method and PCA to calculate phenotypic comprehensive values effectively quantifies the comprehensive traits of C. faberi germplasm. Superior germplasm resources identified include C. faberi Dayipin, C. faberi Jinaosu, C. faberi Chengmei, C. faberi Baohuisu, C. faberi Jiangnanxinjipin, C. faberi Zhengxiaohe, C. faberi Dachenzi, C. faberi Xiuhuimudan, C. faberi Huilanhuban, and C. faberi Duanhuimei, among others. Key traits such as plant type, flower color, sepal, and petal posture can serve as critical indicators for the evaluation of C. faberi germplasm, aiding in the selection of breeding parental materials and innovative utilization of germplasm resources.

Genetically engineered antibodies (GEAbs) represent a giant leap forward in the artificial directed design of antibodies. They exist in forms such as recombinant antigen binding fragment, single chain variable fragment and nanobodies, etc., and have been widely used in various fields of agricultural and food safety. Relevant innovation exploration and research are still ongoing, and their development is extremely rapid. This paper summarized the main derivative forms of GEAbs, the carrying platforms of phage, yeast, ribosomal and mammalian cells on which they rely, and the corresponding antigen-specific antibody targeting screening system. The key technical characteristics of their characteristic functional modifications, such as affinity maturation and enhancement of environmental stress stability, were analyzed through strategies, such as site-directed mutagenesis, chain-shuffling, error-prone PCR, DNA shuffling, homologous or heterologous antibody functional fragments and functional protein fusion. The preparation of corresponding antibody proteins using the expression systems of insect and animal cells, plant tissues, yeast, Escherichia coli (E. coli) and other microorganisms and the potential optimization strategies were summarized too. The application and research status of GEAbs in the immunoassay of agricultural and food safety hazards, such as environmental hazards of origin growing area, pesticides and veterinary drugs inputs, mycotoxins, foodborne pathogenic microorganisms and their toxic metabolites, foodborne allergens were reviewed. Combined with the latest achievements and research experience in the innovative research and development of the simulants for simulating Bt Cry toxin structure and even anti-insect function of Ab2β anti-idiotypic GEAbs and for simulating vancomycin anti-Staphylococcus aureus (S. aureus) function of Ab2β anti-idiotypic GEAbs from author’s team, which is based on the theoretical basis that Ab2β anti-idiotypic antibody, could simulate the structure of antigen and even the function of biological activity. The future development trend and feasible shortcut of GEAbs in green detection and green prevention and control of agricultural and food safety hazards were further discussed. This paper was expected to provide the latest and comprehensive literature with reference value and potential inspiration for the application of GEAbs in the fields of agricultural, food safety and nutrition quality assessment.

【Background】Rongchang pig is one of the excellent local pig breeds in China, but the number of purebred Rongchang pigs is decreasing with the introduction of foreign-bred pigs as well as the shift of the market demand, and this trend seriously threatens the diversity of the genetic resources of pigs in China and the sustainable development of the pig breeding industry. In the process of frozen semen production in local pigs, the differences in post-freezing quality of spermatozoa from different boars are all related to their freezing tolerances, while the sperm lipid composition is one of the key factors affecting their freezing tolerance. 【Objective】The aim of this study was deeply analyze the quality characteristics of spermatozoa of Rongchang pigs with different freezing tolerances and their lipid compositions, and to screen out the candidate markers of sperm freezing tolerance. 【Method】Fourteen Rongchang pig semen were collected for freezing and preservation, and their post-freezing motilities were detected. Relative Motility (post-freezing motility / pre-freezing motility) was used as the criterion for freezing tolerance, and Rongchang pig spermatozoa were screened and grouped into groups for high and low freezing tolerance. Plasma membrane integrity, mitochondrial membrane potential, reactive oxygen species level, apoptosis level and in vitro oocyte penetration ability of spermatozoa from different freezing tolerance groups were detected after freezing, and the extent of freezing damages on the surface and internal microstructure of spermatozoa were observed by scanning electron microscopy and transmission electron microscopy. The medium- and long-chain fatty acid composition of fresh spermatozoa from different freeze-resistant groups was detected by targeted lipidomics technology, and differential fatty acids were screened out. 【Result】5 Rongchang pigs with high freezing tolerance spermatozoa and 5 Rongchang pigs with low freezing tolerance spermatozoa were screened by relative motility; the plasma membrane integrity, mitochondrial activity and in vitro oocyte penetration rate of spermatozoa in the high freezing tolerance group were significantly higher than that of spermatozoa in the low freezing tolerance group after freezing (P<0.05); the apoptosis rate of spermatozoa in the high freezing tolerance group after freezing was significantly lower than that of spermatozoa in the low freezing tolerance group (P<0.05). The surface and internal structural integrity of spermatozoa in the high tolerance group was higher than that of spermatozoa in the low tolerance group after freezing. Targeted lipidomics showed that at least 36 fatty acids were present in Rongchang pig spermatozoa. The content of 11 fatty acids, including palmitic acid and pentadecanoic acid, were significantly different between the sperm of the high and low freezing tolerance groups (P<0.05), and all of them were more abundant in the high freezing tolerance group. 【Conclusion】The spermatozoa of Rongchang pigs with high freezing tolerance were significantly better than those of low freezing tolerance in terms of physiological status, morphology and structure, and in vitro oocyte penetration function, and there were significant differences in fatty acid composition. The differential fatty acids screened in this study, such as palmitic acid, pentadecanoic acid, and arachidonic acid, could be used as candidate markers of freezing tolerance in Rongchang pig spermatozoa. These findings not only provided a new perspective for an in-depth understanding of the biological mechanism of sperm cryoinjury, but also laid a theoretical foundation for the development of efficient and safe cryoprotectants.

【Objective】Rice grain size is a quantitative trait controlled by multiple genes. They can be dissected into a single segment substitution line (SSSL), which is of great significance for their genetic mechanism study and breeding by design. 【Method】Z492, a chromosome segment substitution line in the genetic background of Nipponbare, was used as material to dissect QTL for rice grain size by mixed linear model (MLM) method. 【Result】The F₂ population was constructed from Nipponbare/Z492 to identify four QTL for grain size, including qGL6 and qGL7 for grain length and qRLW7 and qRLW12 for rate of grain length to width. Then three single-segment substitution lines (SSSL, S1-S3) and 3 dual-segment substitution lines (DSSL, D1-D3) carrying these QTL were further constructed. And the SSSL were then used to detect eight QTL for grain size, including qGL6, qGL7 and six newly identified QTL (qGW6, qRLW6, qGW7, qGWT7, qGL12, qGW12). Simultaneously, the genetic model of different QTL in 3 DSSL were analyzed. The results showed that interaction of qGL6 (a=0.26 mm) and qGL7 (a=0.21 mm) produced -0.21 mm of grain length epistatic effect, which resulted in the genetic effect (0.26 mm) of D1 equal to the additive effect of each QTL. Thus, the grain length (7.98 mm) of D1 displayed no difference from those (7.89 and 7.98 mm) of S2 with qGL7 and S1 containing qGL6, while significantly longer than that (7.47 mm) of Nipponbare. The result indicated that it is not necessary to pyramid qGL6 and qGL7 in breeding by design for increasing grain length. qGW6 (a=0.07 mm) and qGW12 (a=0.06 mm) belonged to independent inheritance in D2, thus, the genetic effect (0.13 mm) after pyramiding of qGW6 and qGW12 caused the grain width (3.65 mm) of D2 broader significantly than any of the SSSL with the single QTL. So, qGW6 and qGW12 can be selected to increase grain width in breeding by design. Interaction of qGW7 (a=0.11 mm) and qGW12 (a=0.06 mm) yielded -0.10 mm of epistatic effect, causing the grain width genetic effect (0.07 mm) of D3 parallel to the additive effect of qGW12. Thus, the grain width (3.59 mm) of D3 exhibited no difference with that (3.56 mm) of S3 carrying qGW12, while wider significantly than that (3.44 mm) of Nipponbare and narrower significantly than that (3.66 mm) of S2. 【Conclusion】It is very necessary for breeding by design to identify QTL for different important traits using SSSL and DSSL. Pyramiding different QTL produce various genetic models. Some display independent inheritance, and others exhibit various epistatic effects. In addition, to cross with S1 and S3 can realize the goal of longer, wider and heavier rice grain, and to cross with S1 and S2 can reach the target of heavier grain weight, while to cross with S2 and S3 have no any effects in grain size.

【Objective】 The study aims to measure the iron (Fe) concentration in the grain, flour, and bran of newly developed high-yielding wheat varieties (lines) in major wheat production regions of China. It investigates the impact of yield, yield components, and soil factors on Fe absorption and distribution within the wheat, and determine the effects of these variables on Fe concentrations in its different parts. The objective is to provide a basis for grain Fe nutritional fortification in wheat. 【Method】A study was conducted on 104 newly developed wheat varieties (lines) through multi-point trials across 17 provinces in major wheat production regions of China. The research analyzed Fe concentration in wheat grain, flour and bran, along with yield, yield components, Fe absorption and distribution, soil physicochemical properties, and fertilizer application rates during the 2021-2022 and 2022-2023 growing seasons, to study the Fe concentration in different parts of the grain of newly developed wheat varieties (lines) in China, as well as the absorption and distribution of Fe and environmental influencing factors. 【Result】Significant variations for Fe concentrations were observed in the wheat grain, flour and bran among new varieties (lines) in the major wheat production regions of China,with the range of 20.2-57.1, 2.1-37.5, and 31.2-144.5 mg·kg^-1, and the average of 34.6, 10.8, and 72.8 mg·kg^-1, respectively. Wheat varieties (lines) in the southern wheat regions exhibited higher Fe concentrations in grains and its different parts compared to that in the northern regions, and the Fe concentration in flour and bran showed a positive correlation with its in grain. For every 1.0 mg·kg^-1 increase in grain Fe, flour saw a 0.2 to 0.3 mg·kg^-1 rise, and bran experienced a 1.9 to 2.3 mg·kg^-1 increase. The Fe concentration in grains was negatively correlated with yield, biomass, and spike number. With each 1.0 t·hm^-2 increase in yield, there was a decrease of 1.2 mg·kg^-1 in grain Fe concentration. For every 100×10⁴/hm² increase in spike number, the grain Fe concentration decreased by 0.3 mg·kg^-1. The flour Fe concentration showed negative relationship with Fe absorption in grain, straw, glume and bran. The grain Fe concentration was negatively correlated with calcium, and positively with manganese, copper, and zinc. The grain Fe concentrations varied over locations, and different locations contributing 39% to 70% to the variation in grain Fe concentration. Soil pH, available phosphorus, Fe and manganese as major environmental factors affecting Fe nutrition in wheat grains. Grain Fe concentrations were negatively correlated with soil available phosphorus. Meanwhile, flour Fe concentrations were negatively correlated with soil pH, and positively correlated with soil available iron and manganese. 【Conclusion】High-Fe varieties (lines) were found among the newly developed high-yielding wheat varieties (lines) in China. Maintaining stable spike number, regulating soil pH, increasing grain Fe harvest index, soil available phosphorus, iron, manganese and appropriately applying N, P to enhance soil fertility were conducive to achieving a synergistic enhancement of both yield and Fe concentrations in wheat grain and flour.

【Objective】Husk is an important trait that affects the mechanical harvesting of maize grain, and identification of the genetic loci and candidate genes can provide theoretical basis for genetic improvement of maize husk traits. 【Method】To identify significantly associated single nucleotide polymorphisms (SNPs) and predict candidate genes for three husk traits, 251 maize inbred lines were used as plant materials and evaluated for husk number (HN), length (HL), and coverage (HC) in two environments. The genome-wide association study (GWAS) was conducted by multi-locus random-SNP-effect mixed linear model (mrMLM) with 32 853 SNPs across entire genome. 【Result】The three husk traits exhibited abundant variation among 251 maize inbred lines with 10.65%-40.60% of phenotypic variation coefficients. The variances of genotype, environment, and the genotype×environment interactions were significant at P<0.01 for each trait, and the broad-sense heritability for each trait was more than 80%. A total 92 SNPs significantly associated with three husk traits were identified in two environmental and best linear unbiased predictors (BLUP) across two environments values by GWAS. Among these SNPs, 35 SNPs were significantly associated with HN, and the phenotypic variance explained by single SNP ranged from 1.48% to 10.53%. 33 SNPs were significantly associated with HL, and the phenotypic variance explained by single SNP ranged from 1.61% to 21.69%. 24 SNPs were significantly associated with HC, and the phenotypic variance explained by single SNP ranged from 2.17% to 20.86%. However, none of SNP could be significantly associated with two husk traits. Five of 92 SNPs were stable, as they were repeatedly detected in two environments and BLUP, also they were novel loci for first reported in this study. Based on the five stable SNPs and qRT-PCR analysis for husk tissue of 17 maize inbred lines, three candidate genes (Zm00001d003850, Zm00001d033706 and Zm00001d025612) related to maize husk were screeded out, which encoded BOI-related E3 ubiquitin-protein ligase, GeBP transcription factor, and protein of unknown function, respectively. 【Conclusion】A total of 92 SNPs significantly associated with three husk traits were identified, including five stable SNPs. Three candidate genes were predicted that might be involved in maize husk growth and development.

【Objective】Aiming at the problems of large amount of nitrogen fertilizer input, low utilization rate and single fertilizer source in traditional spring wheat planting in the oasis irrigation area of Northwest China, the effects of multiple cropping green manure after spring wheat on photosynthetic source, growth characteristics and yield of spring wheat under the condition of reduced nitrogen application were studied, with a view to provide the technical support for the construction of a nitrogen-saving and high-yield green planting model of spring wheat in the experimental area. 【Method】The split plot experiment was carried out in the oasis irrigation area of Hexi Corridor from 2021 to 2023. The main area was set up with two planting modes: post-wheat fallow (W) and post-wheat multiple cropping of hairy leaf (W-G), and the split plot was the traditional full nitrogen application of 100% (N1, 180 kg·hm^-2), reduced nitrogen application of 15% (N2, 153 kg·hm^-2) and reduced nitrogen application of 30% (N3, 126 kg·hm^-2). The photosynthetic source, stay-green of leaves, growth characteristics and yield performance related indicators of spring wheat under different treatments were measured and calculated. The Logistic equation of dry matter accumulation, the correlation between different indicators and the compensation index were constructed. The objective was to explore the compensation effect of multiple cropping green manure on the growth and yield of nitrogen-reduced spring wheat. 【Result】Post-wheat multiple cropping of green manure could compensate for the loss of photosynthetic source, growth characteristics and yield caused by nitrogen reduction to a certain extent. Among them, the compensation effect was the best under the condition of multiple cropping green manure after spring wheat combined with 15% nitrogen reduction (W-GN2), which showed super compensation and equal compensation effect. Multiple cropping of green manure significantly increased leaf area index, leaf area duration and stay-green of leaves in spring wheat at the late reproductive stage. Compared with the traditional post-wheat fallow total nitrogen fertilization (WN1), W-GN2 increased the average leaf area index, leaf area duration and stay-green of leaves by 17.7%, 17.5% and 7.6% on the 75-90 days after seedling, respectively. W-GN2 optimized the growth characteristics of spring wheat. Compared with WN1, the average dry matter accumulation, the maximum growth rate of dry matter and crop growth rate under W-GN2 increased by 6.2%, 6.9% and 5.1%, respectively, and the net assimilation rate decreased by 6.2%. Due to the compensation of multiple cropping green manure for photosynthetic source and growth characteristics, the photosynthesis, population growth and material accumulation rate of spring wheat remained high in the late growth stage, which was conducive to the improvement of grain yield. The grain yield under W-GN2 was 14.7% higher than that under WN1, which was mainly attributed to the compensation of the spike number, 1000-grain weight and harvest index by multiple cropping green manure, and W-GN2 was 6.5%, 6.9% and 13.2% higher than that under WN1, respectively. According to the correlation analysis, it was found that W-GN2 treatment had better performance in photosynthetic source, growth characteristics and grain yield formation, and mainly promoted the formation of yield by compensating the photosynthetic source of spring wheat. 【Conclusion】Multiple cropping of hairy vetch after spring wheat with 15% reduction of nitrogen application could be used as a perfect production technology to regulate the photosynthetic source and growth characteristics of spring wheat in the northwest oasis irrigation area to achieve nitrogen saving and yield increase.

【Objective】This study explored the effects of different mulching methods on the production of photosynthetic substances and water use of maize under the intercropping mode of maize and soybean, aiming to determine the suitable mulching method for maize and soybean plantation in dryland agriculture in northern Shaanxi, so as to provide a basis for high-yield and efficient production of maize and soybean and ecological environment protection. 【Method】This study was conducted in irrigated land and nonirrigated land in 2022, using 'Zhonghuang 30' soybean and 'Xianyu 335' maize as materials. The two-factor complete randomized design was carried out, and the control group combined single crop (maize “M”, soybean “S”) and film mulching (bare land, interbrane “J”), and the test group combined intercropping crop (maize “M”, soybean “S”) and film mulching (bare land, interbrane “J” and whole film “Q”), with a total of 13 treatment groups. The characteristics changes of growth, photosynthesis, and water use efficiency of intercropped maize under different mulching methods were studied. 【Result】 (1) From jointing to silking stage, the growth space of intercropped maize was limited, resulting in a disadvantage in aboveground biomass of intercropped maize compared with monoculture. The biomass during the jointing stage of S/MQ, SQ/MJ, and SQ/MQ was 5.1%, 6.3%, and 1.7% higher than that of monoculture M, respectively; under intercropping, SJ/MJ maize plants had the fastest growth rate and a sharp increase in growth. SQ/MQ S/M, S/MJ, SQ/MJ, and SJ/M in dry land had a better promoting effect on the photosynthetic products of maize during the silking stage, and the aboveground biomass was 0.6%-105.9% higher than that of monoculture M. (2) To some extent, intercropping and mulching treatments improved the photosynthetic characteristics of maize, and the net photosynthetic rate (Pn) content of paddy maize. There was a certain degree of positive relationship between stomatal conductance (Gs), cellular CO₂ concentration (Ci) and transpiration rate (Tr). The photosynthetic parameters of SQ/MJ and SJ/MQ were relatively high, while SJ/M and SQ/MQ were lower than non film coated S/M; there was a weak negative correlation between Pn and Ci in dryland maize, and the effect of maize mulching was not significant among different treatments. The Gs of intercropping treatment was 5.7% -38.1% lower than that of monoculture M, and Tr was also reduced by 5.6% -25.6%. Only the Pn of SJ/M and SQ/M, as well as the Ci of SQ/MJ and S/M, were higher than monoculture M. (3) The intercropping film mulching had a significant impact on water use efficiency (WUE). The WUE of the intercropping treatment was 41.1% -74.0% higher than that of monoculture M, among which SJ/M, S/M and S/MJ were relatively high; among all treatments in arid land, SQ/MJ had the highest WUE (19.04 kg∙mm^-1∙hm^-2), followed by SJ/MJ (17.07 kg∙mm^-1∙hm^-2), and the WUE of SJ/M and SQ/M was significantly lower than that of monoculture M by 26.7% and 20.6%, respectively. (4) Compared with monoculture M, intercropping S/MJ between irrigated land and dry land SJ/M and SJ/MJ maize increased yields by 76.8%, 73.0%, and 72.3%, respectively, while soybean yield reduction was relatively less among all intercropping treatments, demonstrating higher economic benefits; dry land intercropping SJ/MJ and SJ/MQ maize increased production by 17.1% and 23.5%, respectively, while economic benefits decreased by 17.5% and 22.8%, respectively. 【Conclusion】Compared with single cropping M, SJ/MJ model improved the photosynthetic performance, biomass, and yield of maize in irrigated land, and improved system economic benefit and promoted water use efficiency. In dry land, through the complementary effect and resource allocation in the intercropping system, it maintained maize yield and improved water use efficiency, but the increase of total input in agricultural materials reduced the economic feasibility. Therefore, in the dryland agriculture of Northern Shaanxi, the intercropping planting pattern of maize with degradable film and soybeans with degradable film was recommended for both irrigated land and moderately irrigated dry farm, aiming to enhance water use efficiency, increase production and profitability, and promote sustainable ecological agriculture development.

【Objective】Apple ring rot is one of the serious fungal diseases in apple production caused by Botryosphaeria dothidea. The aim of this study is to obtain strains of B. dothidea with weak pathogenicity carrying dsRNA viruses, identify the types of viruses, and clarify the distribution of these viruses in China, so as to provide new biological control resources for the prevention and control of apple ring rot and new insights into the diversity and systematic evolution of fungal viruses. 【Method】Samples of branches with typical symptoms of apple ring rot were collected from across China, and pure cultures were obtained through tissue isolation and single-spore isolation. Virus-carrying strains were identified through dsRNA band analysis, and the types of dsRNA viruses carried by the virus-carrying strain WH-2L were identified using high-throughput sequencing and molecular cloning techniques. The presence of two types of dsRNA viruses in B. dothidea from six provinces (autonomous region) in China was determined by RT-PCR. Pathogenicity differences among representative strains carrying different viruses were clarified through pathogenicity tests. Finally, the transmission characteristics of the two viruses were revealed through analysis of vertical and horizontal transmission properties. 【Result】For the first time in apple-producing regions of China, strains of B. dothidea causing apple ring rot were found to be co-infected with two viruses: Botryosphaeria dothidea chrysovirus 1 (BdCV1), belonging to the family Chrysoviridae and genus Chrysovirus, and Botryosphaeria dothidea victorivirus 2 (BdVV2), belonging to the family Totiviridae and genus Victorivirus. It was clarified that BdCV1 and BdVV2 are widely distributed in B. dothidea causing apple ring rot in China. BdCV1 was detected in strains from Liaoning, Shandong, Henan, Hebei, Shaanxi, and Xinjiang, except for Yan’an in Shaanxi and Shijiazhuang in Hebei, with an average detection rate of 53.6%. BdVV2 occurred in Liaoning, Shandong, Henan, Hebei, and Shaanxi, but was not detected in Yan’an in Shaanxi, Shijiazhuang and Handan in Hebei, Aksu in Xinjiang, Taian and Qingdao in Shandong, with an average detection rate of 28.6%. It was clarified that the pathogenicity of strains with co-infection of the two viruses and single infection of BdCV1 on branches, apple fruits, and pear fruits was significantly reduced. The vertical transmission efficiency of BdCV1 and BdVV2 was 100%, and the horizontal transmission efficiency was 9% and 3%, respectively. 【Conclusion】The strain WH-2L of B. dothidea with weak pathogenicity carries two viruses, BdCV1 and BdVV2. The detection rates of BdCV1 and BdVV2 in B. dothidea causing apple ring rot in six apple-producing regions in China were 53.6% and 28.6%, respectively. Both viruses can cause reduced pathogenicity in their hosts, with high vertical transmission efficiency and certain horizontal transmission efficiency, and have potential for development as biological control resources for apple ring rot.

【Background】Hulless barley ear (or spike) rot epidemically occurs only in the Qinghai-Xizang Plateau, which has been getting heavier and spreading more widely in recent years. It has become one of the major diseases in the staple food crop, hulless or naked barley (Hordeum vulgare var. nudum), referred to as Qingke in local areas. It seriously threatens the guarantee of high yield and stable production of hulless barley crops. Grass mite (Siteroptes spp.) plays the role of inoculum transmission vector of the pathogen Dactylobotrys graminicola. The disease cycle is still unclear, and a control method is not available at present. 【Objective】In this study, the migration and clustering of grass mites were investigated in order to disclose the processes of pathogen inoculum transmission and the infection of inflorescence of hulless barley. The results obtained here will serve as a scientific basis for developing technologies for ear rot control. 【Method】Variations in the number of mites in samples of surface soil and on hulless barley plants, as well as their distributions, were detected. The fungi carried by grass mites were microscopically observed and isolated for species identification, and the infection processes of hulless barley inflorescences were also detected under a microscope. The fungal spores stored in the sporothecae of grass mite vectors near the lesions of inflorescences and those collected from the soil were tested using the lactophenol cotton blue dyeing method. The initial invasion time of grass mites into hulless barley seedlings and their distribution within the plants were verified in the greenhouse. The pathogen D. graminicola was inoculated onto hulless barley tissues for testing its pathogenicity. 【Result】The overwintering mites initially moved in from the horn-shaped opening of the first leaf after the blade unfolded and gathered at the adaxial side of its basal part. About 87.63%-99.34% of the grass mites found in hulless barley plants were distributed in their main stems, with only 0.66%-12.37% in tillers. The majority of mites in the main stems (95.48%-99.74%) were gathered around the basal parts of young leaves, over 30% of which moved onto inflorescences at the early booting stage. The incidence of ear rot in the main stem was 6.37 times that of the tiller. Greenish yellow, water-soaked lesions appeared on the glumes and awns of young spikelets, and adult mites were usually found near them at the early booting stage; 28.57% of these mites contained fungal spores in their sporothecae, significantly lower than the 46.70% ratio of spore-carrying mites in the soil. After seedling emergence, the mite density in the soil remained at a relatively low level for a long time until hulless barley was harvested, and it abruptly increased by 2.85 times compared to before sowing. About 88.66% of the fungal isolates from grass mites and 76.47% of those from lesion tissues of inflorescences were identified as D. graminicola, and the pathogen was only strongly pathogenic to the inflorescences. 【Conclusion】The overwintering mites mainly migrated from the soil and flocked to hulless barley seedlings during the early stage after plant emergence, first entering the basal part of the first leaf through the horn-shaped opening formed after leaf blade unfolded. Over 30% of mites clustering around the newly born leaves of a main stem subsequently moved onto the inflorescence at the early booting stage and then released D. graminicola spores to cause infection. The disease cycle of D. graminicola was completed with the essential aid of grass mite mediator. Ear rot mainly infected the main stems of hulless barley plants. It was not until at the repining stage that there were plenty of adult mites produced on the diseased ears, resulting in a significant increase in the mite density in surface soil after harvesting. Therefore, ear rot of hulless barley is a monocyclic disease mediated by vector grass mite.

【Objective】The aim of this study was to clarify the effects of long-term mulching practices on crop yield, soil carbon and nitrogen physical fractions and carbon and nitrogen pool-related indexes, with a view to providing a scientific basis for long-term maintenance of high crop yields and soil fertility in dry-crop farmlands on the Loess Plateau. 【Method】 Based on a field experiment of more than 10 years in Changwu County, Shaanxi Province, three treatments of no mulching (CK), gravel mulching (GM) and film mulching (FM) were set up. From 2018 to 2020, in situ soil samples in the 0-20, 20-40 and 40-60 cm soil layers were collected, and soil samples from each soil layer were grouped by using the physical method. The variation characteristics were investigated, including spring maize yield, and soil organic carbon (SOC), total nitrogen (TN), particulate organic carbon (POC), particulate organic nitrogen (PON), mineral-bound organic carbon (MAOC) and mineral-associated organic nitrogen (MAON) in each soil layer. Based on carbon pool management index (CPMI), nitrogen pool management index (NPMI), and carbon stability index (CSI), the nitrogen stability index (NSI). Combined with correlation analysis, the relationships between the yields and the soil carbon and nitrogen fractions and the related indexes were clarified. 【Result】Compared with CK treatment, the GM treatment showed a decrease in yield, with a 5.8% decrease in mean yield, while the FM treatment continued to increase yield, with a significant 13.6% increase in mean yield. The mean SOC and TN content of the topsoil (0-20 cm) were decreased under both the GM and FM treatments compared with CK treatment, with a significant reduction of 7.3% in the mean SOC content of the topsoil under FM treatment, while it was not significant under GM treatment. Both GM and FM treatments significantly decreased mean POC and PON content in the topsoil and significantly increased MAOC and MAON content in the topsoil compared to CK treatment, i.e. long-term mulching practices significantly decreased labile carbon and nitrogen contents in the topsoil and significantly increased recalcitrant carbon and nitrogen content in the topsoil. Compared with CK treatment, the GM treatment significantly decreased CPMI in the topsoil and significantly increased CSI in the topsoil, whereas the FM treatment significantly decreased CPMI and NPMI and significantly increased CSI and NSI in the topsoil, indicating that the GM treatment significantly increased carbon pool stability of the topsoil, whereas the FM treatment significantly increased both carbon pool stability and nitrogen pool stability of the topsoil. Correlation analyses showed that in addition to POC and MAOC being related to carbon pool indexes, POC was also closely related to NPMI and NSI, while MAOC was also closely related to yield and NPMI. 【Conclusion】Long-term film mulching maintained high crop yields and improved the stability of soil carbon and nitrogen pools, but it reduced topsoil fertility and could be made more sustainable by combining it with other measures to replenish soil organic matter.

【Objective】This study investigated the differential responses of rhizosphere microbial communities, keystones and indicators to nitrogen fertilizer application in black and sandy soils under identical climatic conditions. The aim of this study was to provide a scientific basis for guiding precision fertilization and promoting green production. 【Method】This study was based on a long-term field experiment (12 years) involving nitrogen fertilizer application in a maize continuous cropping system in Jilin Province. The experimental design included two main treatments: sandy soil and black soil. Under each main treatment, three nitrogen levels were applied: 0 (N0), 168 kgN·hm^-2 (N168), and 312 kgN·hm^-2 (N312). Utilizing high-throughput sequencing technology, the differential impacts of long-term nitrogen fertilizer application on the composition, structure, and functional attributes of rhizosphere microbe communities in both black soil and sandy soil were studied. 【Result】Long-term nitrogen fertilizer application significantly decreased the Alpha diversity and changed the community structure of rhizosphere microbes in both black and sandy soils. The greatest impact was observed under N312 treatment, which significantly reduced Alpha diversity by 2.6%-7.5%. The impact of the same nitrogen application on the rhizosphere microbes was more pronounced in sandy soil than in black soil. Species analysis indicated that nitrogen fertilizer application significantly increased the relative abundance of Bacteroidetes and Patescibacteria phylum and decreased the relative abundance of Frimicutes and Chloroflexi, with the N312 treatment having the greatest impact (80%-90%) in both black and sandy soils. Co-occurrence network analysis revealed that the impact of nitrogen fertilizer application on the network structure was greater in sandy soil than in black soil. Moreover, nitrogen fertilizer application significantly influenced 43% of the keystone species in black soil and all keystone species in sandy soil. Random forest analysis indicated that the impact of nitrogen fertilizer application on indicators was more pronounced in sandy soil than in black soil. Compared with N0, the N168 and N312 treatments had no specific indicator species in black soils, whereas two specific indicators were identified under these two treatments in sandy soil, belonging to the Intrasporangiaceae family of the Actinomycetes phylum and the Noviherbaspirillum genus of the Proteobacteria phylum. PICRUSt2 functional prediction revealed that nitrogen fertilizer application significantly affected 88.5% of nitrogen transformation-related functional genes in black soil and 96.2% in sandy soil, with a greater influence observed at higher nitrogen application rates. 【Conclusion】The research findings suggested that nitrogen fertilizer application significantly reduced the diversity of rhizosphere microbial communities, and changed the community structure and species composition characteristics, resulting in significant differences in nitrogen transformation-related functional genes. The overall impact of nitrogen fertilizer application on rhizosphere microbes was more pronounced in sandy soil than in black soil, with a greater influence observed at higher nitrogen application rates. Therefore, it was important to further promote N fertilizer reduction in black and sandy soils to maintain the stability of rhizosphere microbial community structure in farmland.

【Objective】In order to improve the simulation accuracy of N₂O emissions by using APSIM model, this study used Whale Optimization Algorithm (WOA) to optimize the default parameters related to soil N₂O emissions in the APSIM model to improve the accuracy and applicability of the model in simulating soil N₂O emissions in the semi-arid agricultural region of northwest China, for providing support for precise assessment and management of greenhouse gas emissions in agricultural activities. 【Method】This study used field experimental data measured by the Anjiapo integrated long-term positioning test station in Anding District, Dingxi City, Gansu Province from 2020 to 2021, combined with meteorological data provided by the Meteorological Bureau from 1970 to 2021, to optimize the four key parameters of N₂O formation stage in the APSIM model (soil nitrification potential (nitration_pot), concentration of ammonium nitrogen at semi maximum utilization efficiency (nh4_at-half_pot), denitrification coefficient (dnit_rate-coeff), and power term of denitrification water coefficient (dnit_wf_power) using the WOA for single objective and multi parameter optimization. The accuracy of the optimized APSIM soil N₂O emission model was evaluated by comparing the errors between the default parameter simulation values, optimized parameter simulation values, and measured values of the APSIM model. 【Result】Through multiple executions of the optimization program, the optimal combination of four parameters was ultimately determined. Among them, the soil nitrification potential was 7.62 mg·kg^-1·d^-1, the concentration of ammonia nitrogen at semi maximum utilization efficiency was 49.3 mg·kg^-1, the denitrification coefficient was 0.00063, and the power term of the denitrification water coefficient calculation was 0.64. Compared with the default parameters of the APSIM model, the coefficient of determination R² increased from 0.432 to 0.719, the root mean square error (RMSE) decreased from 39.42 to 25.37 μg·m^-2·h^-1, and the normalized root mean square error (NRMSE) decreased from 18.51% to 11.92%. The whale algorithm exhibited significant global search capability and fast convergence during the optimization process. The optimized APSIM model significantly improved the accuracy of simulating soil N₂O emissions, indicating that this method could achieve rapid and accurate calibration of model parameters. 【Conclusion】By applying WOA, four key parameters were precisely adjusted, which significantly reduced the prediction error of the model and significantly improving the performance of the APSIM soil N₂O emission model. The optimized model has shown higher accuracy and applicability in the semi-arid agricultural region of northwest China, which also proved the effectiveness of the optimization strategy.