【Objective】Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), significantly reduced wheat production worldwide. Breeding resistant wheat varieties is currently considered to be one of the most economical and effective ways to control this disease. Understanding the resistance level of Chinese and International Maize and Wheat Improvement Center (CIMMYT) wheat breeding materials and the distribution of known disease resistance genes will greatly helpful for discovering the new resistance resources and improving the utilization efficiency of disease resistance genes.【Method】In the present study, we phenotyped 153 wheat breeding lines derived from China and CIMMYT at both seedling against prevalent Chinese Pst races CYR33 and CYR34. In 2018-2019, 2019-2020 and 2020-2021, using the pst races CYR33 and CYR34 to identify the materials at the adult plant stages in Ezhou, Hubei. In addition, we used the gene-based or closely linked molecular markers of known stripe rust resistance genes Yr5, Yr9, Yr10, Yr15, Yr17, Yr18, Yr26, Yr29 and YrSP to genotype the whole set of wheat collections.【Result】We found 10 lines immune against CYR33 at the seedling stage (IT: 0), including seven Chinese cultivars (Shannong 28, Luomai 163, Shimai 13, Zhongyi 6, Tanmai 98-2, Zhongmai 175, Taishan 21) and three CIMMYT lines (CIM-53, CIM-60 and CIM-71). However, only two cultivars, Tanmai 98-1 and Shannong 102, showed immune to CYR34 at the seedling stage. Based on the three years field tests, we found 64 lines showed highly resistance to stripe rust (final disease severity, FDS≤5%), including seven Chinese cultivars and 57 CIMMYT lines. The molecular marker analysis of known stripe rust resistance genes showed that there were 31, 23, 73, 2, 4, 50 and 2 lines carrying resistance genes Yr9, Yr10, Yr17, Yr18, Yr26, Yr29 and YrSP, respectively. None of any lines had Yr5 and Yr15. Based on the phenotype, only CIM-53 showed immune against two races at both seedling and adult plant stages (IT=0, FDS=0) and it might carry the known stripe rust resistance gene combination of Yr17+Yr29 based on the genotype.【Conclusion】A total of 153 wheat collections from China and CIMMYT were showed adult plant resistance to the prevalent pst races. Among these, Chinese wheat varieties mainly carry Yr9, Yr10 and Yr26, while CIMMYT wheat line mainly carry Yr17,Yr18 and Yr29, indicating that near-immunity resistance of CIMMYT wheat lines due to combinations of 1-2 moderate seedling resistance gene and 2-3 adult plant resistance genes resulting in durable resistance. Therefore, it is very urgent to expand the resistance sources and identify new resistance genes for pyramiding more genes biotechnology methods to develop new wheat varieties with durable rusts resistance and good agronomic traits. This plays an important role for controlling stripe rust in China by improving the resistance level of wheat variety overall.

【Objective】There are many commercial inactivated vaccines against the H9 subtype avian influenza approved for use in China, and their protection efficacy and selection have been widely concerned by farmers. Evaluation of protection efficacy of main commercial vaccines against H9N2 viruses recently isolated in the field are of great significance for guiding the prevention and control of H9 subtype AI by immunization in China.【Method】According to the vaccine batch release of the National Veterinary Drug Basic Information Database in China, 4 commercial vaccines (labeled as A-D) with large batches were selected from 40 kinds of sold H9 commercial vaccines. The four H9N2 subtype AIV, CK/XJ/S1204/2015, DK/JX/S4512/2017, CK/YN/S1666/2020 and CK/NX/S4590/2020, belong to h9.4.2.5 branch, isolated at different times and places were used in this study to evaluate the protection efficacy of selected commercial H9 subtype AI vaccines. The 50% chicken embryo  infection (EID₅₀), 50% chicken infection (CID₅₀), and 50% cell infection (TCID₅₀) of the four viruses were tested to determine the challenge dose of the animal experiment and the infection dose of the cell test. 40 3-week-old SPF chickens were injected intramuscularly with 4 kinds of inactivated vaccine, and groups of 10 similar SPF chickens were inoculated with PBS as control group. 3 weeks post vaccination(p.v.), the serum of all experimental chickens were collected before challenge, hemagglutination inhibition (HI) and neutralization (NT) antibody titers were detected by HI test and neutralization test; The 40 immunized chickens of each vaccine were randomly divided into four groups, 10 chickens of each vaccine and 10 control chickens were infected intranasally with the 10CID₅₀.of each H9N2 virus. Oropharyngeal and cloacal swabs were collected on days 3 and 5 post challenge(p.c.) for virus shedding detection and calculation of the protective rate of each vaccine. 【Result】The CID₅₀ of the four strains were 10^3.5 EID₅₀/0.1 mL, 10^2.5 EID₅₀/0.1 mL, 10^2.5 EID₅₀/0.1 m and  10^3.5 EID₅₀/0.1 mL, respectively. At three weeks p.v., the mean HI antibodies titers against the commercial H9 subtype HI test antigen (CK/SH/10/2001) in 4 groups of vaccinated chickens ranged from 9.4log2 to 11log2, the mean HI antibodies titers against challenge virus in 4 groups of vaccinated chickens ranged from 4.6log2 to 10.8log2, and significant differences of HI antibodies titers were observed among different vaccine groups, the maximum difference of mean HI antibodies titers were 64-fold among them. The mean NT antibodies titers against challenge virus in 4 groups of vaccinated chickens ranged from 6.7log2 to 12.2log2, the maximum difference of mean HI antibodies titers were 32-fold among them, the HI antibody and NT antibody of the control group were negative. After intranasal infection with different H9 viruses, the immune effects of the four vaccines were quite different. In CK/XJ/S1204/2015 challenged groups, 3 vaccines (B-D) could provide more than 80% protection. In DK/JX/S4512/2017 challenged groups, 1 vaccine (B) can provide more than 80% protection. In CK/YN/S1666/2020 challenged groups, 2 vaccines (A and B) can provide more than 80% protection. In CK/NX/S4590/2020 challenged groups, the protection efficacy of the four vaccines (A-D) were all less than 80%. In the same period, the virus shedding rate of chickens in the control group was more than 8 /10. 【Conclusion】There was a great difference in the immune protection efficacy of the four kinds of commercial vaccines after challenge with recently isolated H9 strains, and the difference of antigenicity between vaccine antigens and isolates was the main reason for the decrease of immune protection efficacy of the commercial vaccines. The titers of HI antibody and NT antibody against H9N2 prevalent strains could be as important data for evaluation of the commercial H9N2 AI vaccines. This study provides scientific references for selection and usage of the commercial vaccines against H9N2 AI.

【Objective】The effect of subsoiling combined with straw returning on soil pore structure of black soil in Northeast China is lack of definite judgment. Aimed at such problem, our research was conducted in order to provide scientific basis for the influence mechanism of this measure on soil structure of black soil and the establishment of reasonable tillage.【Method】In this study, a 5-year field positioning experiment conducted in Qinggang County, Suihua City, Heilongjiang Province, a typical black soil area in Northeast China was used as a platform. Farmers’ conventional treatment (FP) , 25 cm subsoiling alone treatment (T2), 25 cm subsoiling combined with straw returning treatment (T3) and 35 cm subsoiling combined with straw returning treatment (T4) were set. The visualization and quantification of soil pore structure were studied using CT scanning technology, and combined with field capacity and bulk density to explore the effect of subsoiling combined with straw returning on the pore structure of black soil. 【Result】The results showed that the two-dimensional and three-dimensional images of soil pores clearly showed that the pore distribution at 0-20 cm soil layer was significantly less than that at 20-40 cm soil layer in all treatments, while the pore distribution of suboiling combined with straw returning treatment (T3 and T4) was significantly higher than that of FP treatment, and their macropores with more complex structure were increased. Quantitative analysis showed that compared with FP treatment, the total porosity of 20-30 cm soil layer was significantly increased by 103.0% (P<0.05) under 25 cm subsoiling alone treatment (T2), which was achieved by significantly increasing the micropores porosity(pore diameter d≤0.50 mm) by 91.3% and mesopores porosity (0.50 mmP<0.05). While subsowing combined with straw returning treatments (T3 and T4) significantly increased the total porosity of 0-30 cm soil layer by 109.8%—382.7% (P<0.05), which was achieved by significantly increasing the macropores porosity (d>1.00 mm) by 221.5%-661.7% and the mesopores porosity by 105.4%-544.9% (P<0.05). In addition, compared with FP treatment, subsoiling combined with straw returning (T3 and T4) significantly increased the fractal dimension of soil pores at 0-30cm soil layer by 9.9%-17.7% (P<0.05), decreased the Euler number by 32.4%-66.4% (P<0.05), significantly increased the field water capacity by 24.2%-40.6% (P<0.05). Further analysis showed that the different pore size porosity and total porosity was significantly positively correlated with field capacity and fractal dimension, but significantly negatively correlated with Euler number (P<0.01). 【Conclusion】Subsoiling combined with straw returning measure can improve porosity of macropores and mesopores pore of black soil, improve pore structure and connectivity, and increase field capacity, which can be recommended measure for rational tillage construction in black soil of Northeast China.

【Objective】A set of variety DNA fingerprint identification system based on the core markers of genes regulating rice important traits was constructed, which will establish a foundation for strengthening the germplasm management and protection of the mainly promoted semi-waxy japonica rice varieties with high eating quality,【Method】34 semi-waxy japonica rice varieties mainly cultivated in Jiangsu, Zhejiang and Shanghai were used as the test materials. The key differential sequence sites in genes regulating rice important traits were screened and core SNP or InDel markers were developed through multiple methods such as polymorphism testing of existing markers, gene sequence alignment from public databases and genome resequencing. SNP markers were developed into simple PCR markers based on electrophoretic bands by As-PCR technology. Genotype information was obtained by electrophoretic band characterization and type analysis, and the DNA fingerprint database of the semi-waxy japonica rice varieties was constructed. 【Result】 54 core markers derived from 40 key genes regulating rice important traits were obtained, including 18 SNP and 36 InDel markers; 155 characteristic and effective bands were identified by 54 markers in the tested rice varieties, which were transformed into 155 0/1 data sites. The DNA fingerprint database of each variety was established and could distinguish it from all tested varieties. Genetic diversity analysis showed that the variation range of genetic similarity among varieties was 0.47~0.90, among which the lowest similarity coefficient was detected between Nanjing 7718 and Suxiangjing 100, while the highest similarity coefficient was detected between Nanjing 9308 and Nanjing 9036, among which there were 8 differential data sites. Genetic relationship analysis indicated that 34 varieties were divided into 6 branches, of which Nanjing 7718 is an independent branch, suggesting it has a distant relationship from other varieties. Further verification of the identification effect of core markers showed that the set of markers could effectively distinguish 14 new semi-waxy japonica rice varieties. The cluster diagram showed that they were distributed in three groups of II, III and IV, confirming the differences of genotype information among varieties; using this set of markers, the authenticity of an unknown semi-waxy rice variety was also identified. According to genotype and cluster analysis, it was determined as Nanjing 9108.【Conclusion】After optimization and screening, 54 core markers that could accurately distinguish all the tested semi-waxy japonica varieties were obtained, and developed into simple PCR markers detected by electrophoresis. Using this set of marker combinations, the DNA fingerprints of 34 semi-waxy japonica varieties in Jiangsu, Zhejiang and Shanghai were constructed.

【Objective】Fruit weight and soluble solid content (SSC) are two important quantitative traits in peach which are concerned by breeders and controlled by multiple minor genes. Therefore, it is difficult to perform early prediction by a single marker. As a novel genome-wide tool, genomic selection has been applied in fruit crops and expected to enhance breeding efficiency of those quantitative traits. However, its application effect in peach and influencing factors still need to be further explored.【Method】The objectives of this study were to assess the accuracy of prediction in nature and cross populations of peach for fruit weight and soluble solid content (SSC) by using genomic selection. In this study, the training population comprised 520 individuals were selected as materials. Using the genotypic data for 48,398 SNPs obtained from the resequencing results of above training population, a total of 11 genome-wide prediction models were built to select the optimum model for fruit weight and SSC. Then, we calculated the genomic breeding values of a small panel of nature population comprised 56 individuals and 29 cross populations comprising 1145 seedlings.【Result】The average sequencing data of each variety of the three groups was 1.95~3.52 Gb, and the sequencing depth was 5.29~10.79×. The sequencing data of the training natural population was algned with the reference genome, a total of 5,065,726 single nucleotide polymorphism (SNPs) were obtained. After removing the SNPs with high missing rate more than 20% and minor allele frequency lower than 0.05, a total of 48,398 SNPs on the genome were randomly selected for constructing whole-genome selection models for the training population. The model with the highest prediction accuracy for fruit weight is BayesA, and the model with the highest prediction accuracy for SSC is randomforest. Using the above two models, we found that the goodness of fit between the predicted breeding values and observed phenotype of fruit weight was 0.4767~0.6141, higher than that of SSC (0.3220~0.4329) in nature populations. And in cross populations, the prediction accuracy of fruit weight was 0.2319~0.4870, also showing higher than that of SSC (0.0200~0.2793).. The results also showed that the prediction model constructed by training natural populations was more accurate in predicting natural populations but of cross populations. Taking fruit weight as an example, we also found that only 17.78% of the seedlings need to be retained by genomic selection when targeted large fruit. Its efficiency is significantly higher than that of single and double marker selection. Finally, the effects of population dispersion, heritability and population structure on prediction accuracy also were discussed. The results indicated that prediction accuracy may be mixed and affected by a combination of several factors.【Conclusion】In this study, a suitable genomic selection model for peach fruit weight and SSC was screened and confirmed that the prediction efficiency of genomic selection was significantly higher than that of single marker selection. The results underline the potential of genomic prediction to accelerate breeding progress of these two quantitative traits in peach.

【Objective】This study aims to reveal the development of segment membrane which contributes to citrus fruit mastication. 【Method】Using different citrus types (hybrid citruses including Ehime No. 30 and Nova, Okitsu Wase satsuma mandarin, navel oranges including Yuanfeng and Newhall, and pumeloes including Anjiang and Jiangyong), the main physiological and biochemical properties of segment membrane were analyzed by comparisons in tissue development and cell ultrastructure.【Result】The results showed that rough outside but smooth inside of segment membrane occurred in all citrus types. Obviously waxy layer grew on the inside of segment membrane under which one or two cell layers with thickened cell wall arranged neatly. Cell density decreased gradually from inside to outside in segment membrane. Occurrence of wax layer in the inside and morphological changes of cells under the wax layer emblematized the maturation of citrus segment membrane. For pomelo, the thickest segment membrane linked with the worst mastication was caused from a large number of cell layers, enlarged cell size and more pectin in segment membrane. At early fruit development from squaring stage to flower withering stage, ventricles differentiated already in the ovary and the intervals between ventricles would develop into segment membranes. In the period, parenchyma cells in the intervals exhibited equal cell size and arranged neatly, having no segment membrane characteristics. With fruit enlargement and maturation, segment membranes of Shatian pomelo had the most cell layers and the longest cell wall thickening period. Segment membranes of Shatian pomelo showed significantly higher pectin content than that of Yuanfeng navel orange and Juxiangzao Satsuma mandarin. Segment membranes of Yuanfeng navel orange had medium cell layers and moderate cell wall thickening period, in which protopectin was higher than that of Juxiangzao Satsuma mandarin. Segment membranes of Juxiangzao exposed the least cell layers and the shortest cell wall thickening period. In October when Juxiangzao matured, segment membrane protopectins in Shatian pomelo, Yuanfeng navel orange and Juxiangzao Satsuma mandarin were 364.22, 208.48 and 165.39 mg.g^-1 respectively, with Shatian pomelo reaching 74.7% and 120.2% higher than another two varieties. 【Conclusion】Segment membrane thickness, cell layers in segment membrane and degree of cell wall thickening associate with citrus fruit mastication. Pectin content could reflect the mastication of citrus segment membranes.

【Objective】 Eestern and Southern Gansu is one of the epidemic centers of stripe rust and over-summering region for Puccinia striiformis f. sp. tritici (Pst) with continuous emergening of new Pst races in Northwestern China. The objective of this study is to analyze the genetic architecture of stripe rust resistance in winter wheat cultivars grown in those regions since 1990s for a better genetic diversity control of the disease, breeding of durable resistant cultivars, sustainable green and healthy ecological agriculture in Southern Gansu.【Method】The seedling and adult plant stage resistance to the prevailing Pst races CYR33, CYR34, etc. of 117 wheat cultivars (lines) were evaluated at greenhouse in 2021 and field trials in Qingshui of Gansu and Pixian of Sichuan, respectively, during 2019-2020 and 2020-2021 cropping seasons. Molecualr markers for 15 Yr genes were also applied to detect the presence of known stripe rust resistant genes. 【Result】Of the 117 varieties and lines tested, thirty-four (29.1%) were found to perform adult plant stage resistance (APR) in the field, among of these, 25.6% and 3.4% of cultivars were released in Southern Gansu, and eastern Gansu, respectively. Another 25.6% susceptible cultivars from Southern Gansu exhibited slow rusting with disease severity (DS) less than 20%. Eighty-two cultivars (70.1%) were resistant to the race CYR33 of Pst at the seedling stage. Among them, 67 (57.3%) and 15 (12.8%) were planted in Southern and eastern Gansu, respectively. However, only seven (6.0%) of the total entries were resistant to the dominant race CYR34 at the seedling stage, and all of these were cultivars from Southern Gansu, such as Lantian 131 etc. The stripe rust resistant cultivars named as Lantian, Zhongliang, and Tianxuan series at both seedling and adult plant stages were mainly released after 2010. Molecular markers screening identified the presence of Yr9 (49.6%), Yr10 (1.7%), Yr17 (12.8%), Yr18 (7.7%), Yr26 (12.8%), Yr28 (20.5%), Yr29 (10.3%), Yr30 (34.2%), Yr41 (2.6%), Yr46 (16.2%), YrZH22 (15.4%) and YrZH84 (27.4%) in some cultivars, preferly as 2-5 genes combinations in 73 (62.4%) cultivars. Pyramiding of YrZH84, YrZH22, and Yr17 with other stripe rust resistance genes could provide better disease resistance than other gene combinations. In addition, high frequency of Yr10, Yr17, Yr18, Yr28, Yr29, Yr30, Yr41, and Yr46 was detected in wheat cultiuvars grown in the dry highland Pst oversummering region. However, Yr26, Yr30, YrZH22 and YrZH84 were mainly identified in wheat cultuvars of the valley Pst overwintering region, indicating significant genetic architecture difference for the stripe rust resistance genes between the cultivars of the oversummering and overwintering regions. Higher genetic diversity of stripe rust resistance genes was found in the cultivars of the oversummering region, compared with that released in the overwintering region. 【Conclusion】Our results revealed the current status of stripe rust resistance genes and their utilization in winter wheat cultivars of Gansu, the northwest oversummering region for Pst of China, in the past 20 years. Diversification of stripe rust resistance genes have been successfully applied in the winter wheat breeding program to develop commercial wheat cultivars and lines for sustainable control of the stripe rust disease. The development of wheat cultivars with stacked stripe rust resistance genes has solved the historical problem of wheat cultivars with narrow genetic background and mono-resistance gene, domonstrating the successful control of wheat stripe rust epidemics using genetic diversity of wheat resistance gene in this region. The present study provides theoretical basis for genetic diversity control of stripe rust disease and set an example for the sustainable green ecological agriculture by breeding wheat cultivars with durable disease resistance.

【Objective】Nitrogen (N) plays a key role in determining biomass and yield in crop production. NRT2s, the high affinity nitrate transporter genes, are mainly activated under low nitrogen stress condition and have been implicated in nitrate absorption and remobilization. This study will screen NRT2 gene family responding to low-nitrogen condition (1/20 of the normal level) and conduct a preliminary functional analysis of AhNRT2.7a in order to provide target genes for breeding new peanut varieties with higher nitrogen utilization efficiency (NUE)，which will help to achieve the goal of to improve crop production with less N fertilizer demand and environmental degradation. 【Method】The spatio-temporal expression patterns under normal and low-nitrogen conditions of five peanut NRT2 genes, AhNRT2.4, AhNRT2.5b, AhNRT2.5c, AhNRT2.7a and AhNRT2.7b, were investigated. Using the cDNA of Huayu6309 as template, full length of AhNRT2.7a CDS was cloned and bioinformatic analyzed. Subcellular localization of AhNRT2.7a was conducted by construction of transient expression vector and transformation of Arabidopsis protoplasts. In order to explore the gene function of AhNRT2.7a, heterologous overexpression of the AhNRT2.7a gene in Arabidopsis were performed. Transgenic plants were used to determine chlorophyll content, nitrogen accumulation and the enzymatic activities of glutamine synthetase (GS), glutamate synthetase (GOGAT), nitrate reductase (NR), nitrite reductase (NiR) and glutamate dehydrogenase (GDH) under normal and low-nitrogen conditions.【Result】Four NRT2 genes of peanut were highly expressed in response to low nitrogen stress, and AhNRT2.7a was highly expressed in the stems and leaves. The total length of 1 380 bp was obtained, encoding a 459-amino acid protein with a molecular weight of 49.35 kD. The total of 12 typical transmembrane protein domains with hydrophobic regions was predicted. Bioinformatics analysis showed that the amino acid sequence had 99.56% sequence similarity with the cultivated peanut (Arachis hypogaea L.), followed by the wild-parents AA (A. duranensis) and BB (A. ipaensis). Subcellular localization analysis revealed that AhNRT2.7a was located in the cell membrane. Transgenic Arabidopsis plants for over-expressing AhNRT2.7a were conducted. Relative content of chlorophyll in mature and young leaves was significantly higher than that in wild-type Arabidopsis under different nitrogen supply. Meanwhile, the activity of five enzymes involved in nitrogen metabolism were examined. Furthermore, uptake, assimilation and re-mobilization of N, concentration of phosphorus and potassium were determined. The results have revealed that the activity of the two nitrogen metabolizing enzymes (NR and GS) and nitrogen accumulation in transgenic plants were significantly higher than in wild-type Arabidopsis.【Conclusion】These results indicated that AhNRT2.7a could enhance the nitrogen use efficiency (NUE) in plants, and also improve carbon metabolism. AhNRT2.7a seems promising as a candidate gene in breeding new peanut varieties with higher NUE.

【Objective】Accurate monitoring and rational application of nitrogen are particularly important for healthy growth, yield and quality improvement of wheat, and reduction of environmental pollution and resource waste. To develop UAV-based models for accurately and effectively assessment of the plant nitrogen content in the key growth stages of wheat growth, explore the transferability of the models constructed based on machine learning methods. 【Method】Winter wheat experiment plots in Shang shui country, Henan province, China were conducted from 2020 to 2022. Based on the K6 multichannel imager mounted on DJM600 UAV, 5-band (Red, Green, Blue, Red edge, and Nir) multispectral images were obtained from a UAV system in the stages of jointing, booting, flowering and filling in winter wheat, and used to calculate 20 vegetation indices and 40 texture features from different band combinations. Correlation analysis was used to screen the sensitive characteristics of nitrogen content in winter wheat plants from the 65 image features. Combining the sensitive spectral features and texture features of the nitrogen content of winter wheat plants, BP neural network (BP), random forest (RF), AdaBoost, and support vector machine (SVR) machine learning regression methods were used to build plant nitrogen content models, and compared for the model performance and transferability. 【Result】(1)The correlation coefficients between plant nitrogen content and image features passed the test of 0.01 extremely significant level, including 22 spectral features and 29 texture features. (2) 51 spectral and texture features were adopted to build four machine learning models. The estimates of plant nitrogen by the RF and AdaBoost methods were relatively concentrated, mostly close to the 1:1 line; while the estimates from the BP and SVR methods were relatively scattered. The RF method was the best, with R², RMSE, and MAE of 0.81, 0.42%, and 0.30%, respectively; The SVR method was the worst, with R², RMSE, and MAE of 0.66, 0.54% and 0.40 %, respectively. (3) The prediction effects of the four methods on the nitrogen content of W0 and W1 treatments trained using W1 and W0 treatments were the same as those trained using both W0 and W1 datasets, both of which were closer to the 1:1 line for the RF and Adaboost methods. The R² of transfer prediction results for the models constructed by BP, RF, Adaboost, and SVR methods were 0.75, 0.72, 0.72, and 0.66 for the prediction of nitrogen content in W0 treatment and 0.51, 0.69, 0.61 (trained using data from W1 treatment) and 0.45 for the prediction in W1 treatment (trained using data from W0 treatment), respectively.【Conclusion】All models showed strong transferability, especially the RF and Adaboost methods, in predicting winter wheat nitrogen content under rainfed and irrigation water management.

【Background】 Due to their high pluripotency, bovine embryonic stem cells (BESCs) have important application values in cattle breed conservation, breed selection and studying the regulation mechanism of livestock embryo development. However, studies on the maintenance of pluripotency and differentiation of BESCs are limited, the regulative mechanism remain unclear. 【Objective】To investigate the effects of different concentrations of Pladienolide B (PlaB) on the expression of pluripotent markers, totipotent markers and embryonic cell-lineage genes as well as the cell viability of BESCs which will provide reference and theoretical basis for improving the developmental potency of BESCs.【Method】Immunofluorescence was used to detect the expression of pluripotent markers of bovine BESCs, and real-time fluorescence quantitative PCR (RT-qPCR) was used to detect the effects of different concentrations of PlaB on the expression of spliceosome, totipotent markers and embryonic cell-lineage genes of BESCs. RT-qPCR and Western Blot were used to detect the effects of different concentrations of PlaB on both mRNA and protein expression of pluripotent markers of BESCs. CCK8 and EDU staining was used to detect the effects of different concentrations of PlaB on the proliferation of BESCs. 【Result】1. RT-qPCR results showed that the mRNA expression levels of SF3B1 and SF3B2 in EPSCM-BESCs were significantly down-regulated by 0.5nM to 1.5nM PlaB; When the PlaB concentration was 1.5nM, the mRNA expression of SF3B1 and SF3B2 in CTFR-BESCs were decreased; When the PlaB concentration ranged from 0.5nM to 1.5nM, the mRNA expression levels of SF3B4 and SF3B5 in both CTFR-BESCs and EPSCM-BESCs were increased in a dose-dependent manner. Furthermore, PlaB significantly down-regulated mRNA expression of SF3B6 in the CTFR-BESCs. While PlaB concentration ranged from 0.5nM to 1.5nM, the mRNA expression of spliceosome LSM4 both in EPSCM-BESCs and CTFR-BESCs were significantly down-regulated. The concentration from 0.5nM to 1.5nM PlaB significantly down-regulated the expression levels of EFTUD2 mRNA in CTFR-BESCs; The mRNA expression of EFTUD2 mRNA was significantly down-regulated in BEPSCM-BESCs with 1nM and 1.5nM PlaB while PlaB concentration from 0.5 to 1.5nM, both the mRNA expression and protein levels of the pluripotent markers OCT4, SOX2 and NANOG in CTFR-BESCs and EPSCM-BESCs were up-regulated in a dose-dependent manner. By the concentration range from 0.5 to 1.5nM, PlaB dose-dependently up-regulated the mRNA levels of totipotent markers such as MDM2, PID1 and BTG2 in CTFR-BESCs and EPSCM-BESCs, while the mRNA levels of DDIT4 and PDRG1 were down-regulated. The mRNA expression of embryonic cell lineage genes in the CTFR-BESCs were up-regulated while the PlaB was added. The addition of PlaB in EPSCM-BESCs significantly reduced the expression of GATA4, GATA6, SOX7 and other embryonic cell lineage genes, but had no significant effect on ZIC1. The cell viability of CTFR-BESCs and EPSCM-BESCs showed a downward trend with increasing of PlaB dose and treatment time. And CTFR-BESCs was more sensitive than EPSCM-BESCs. 【Conclusion】PlaB significantly up-regulated the expression of pluripotent markers and partially totipotent markers in CTFR-BESCs and EPSCM-BESCs. The expression of gene lineages and cell viability in EPSCM-BESCs were decreased. The effective concentration and effects on gene expression of PlaB in the two BESCs were not completely consistent. Due to the inhibiting effect of PlaB on cell viability of BESCs, further studies are needed to optimize the culture system.

【Objective】Understanding the distribution and variation characteristics of PWL family in different rice blast strain populations is of great significance for studying the genetic diversity and specificity of different rice blast strain populations. 【Method】In this study, 8 pairs of specific primers were designed for the promoter region and CDS region of PWL gene family according to the avirulence (Avr) gene sequences published in NCBI. DNA was extracted from 397 Ｍonospora oryzae isolates collected from different regions of Heilongjiang and Hainan provinces in 2020, and the avirulence (Avr) gene were amplified by PCR and detected by agarose gel electrophoresis. Representative strains from different regions were selected from the detection results and the amplified fragments were sequenced. The sequencing results were compared with the base and amino acid sequences of the promoters and CDS regions of the corresponding avirulence (Avr) gene in NCBI.【Result】The results of PCR electrophoresis showed that PWL1 was not detected in all strains; specific fragments of PWL2, PWL3 and PWL4 were amplified in Heilongjiang and Hainan provinces, indicating that these three genes were distributed in the two provinces with different distribution frequencies and variation types. The distribution frequency of PWL2 was the highest in Heilongjiang Province and Hainan Province, with 98.14% and 100%, respectively. The distribution frequencies of PWL3 and PWL4 in the two provinces were significantly different, with 89.30% and 82.79% of the two genes in the Heilongjiang strain and 5.49% in the Hainan strain, respectively. Through the analysis of avirulence (Avr) gene combinations, the results showed that the combinations could be divided into five types, which were PWL2, PWL3, PWL2+PWL3, PWL2+PWL4, PWL2+PWL3+PWL4. Among them, the Heilongjiang strain contained all combination types, while the Hainan strain contained only two, indicating that the Heilongjiang strain was richer in avirulent genotypes than the Hainan strain. Sequencing of the PCR products of PWL gene family showed that the PWL gene family has abundant mutation sites in promoter region and CDS region, which can be divided into 9 types with point mutation and deletion as the main mutation types, and the mutation types of different strains from different populations are specific and consistent. Among them, PWL2 detected five types of variation PWL2- (1, 2, 3, 4, 5), and the base sequence changes lead to amino acid sequence missense mutations. Two variants were detected in PWL3 and PWL4, respectively, which were PWL3- (1, 2) and PWL4- (1, 2). Frameshift mutations occurred in both PWL3 and PWL4, which changed the following amino acids, leading to premature termination of translation.【Conclusion】The distribution and variation types of PWL gene family in different populations of blast strains showed regional differences, and the variation sites were abundant.

Wheat stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is a devastating disease threaten food security in China and worldwide. Epidemics of wheat stripe rust have been under control through applying resistant cultivars and crop protection approaches. However, due to climate change, innovation of cropping system, improvement of breeding technology, yield level enhancement of wheat cultivars, variation in structure and frequency of virulence genes in Pst populations in the new Era, the current status of stripe rust resistance genes in wheat breeding programs need to be evaluated. The results could provide useful information for applying stripe rust resistance genes to develop new wheat cultivars with broad-spectrum and durable rust resistance. After multiple year’s stripe rust resistance survey, genetic analysis, molecular tagging and mining of stripe rust resistance genes in wheat cultivars and advanced breeding lines, the current status of major stripe rust resistance genes utilization was reviewed. We summarized the present situations of major stripe rust resistance gene discovery and germplasm innovation, the most frequently used stripe rust resistance genes, new strategy for pyramiding adult plant partial resistance and all stage resistance, and molecular marker assisted selection for developing wheat cultivars with broad spectrum and durable resistance in China. This review also proposes the major research areas in wheat stripe rust resistance breeding in the New Era.

【Objective】Drought is one of the foremost abiotic stress limiting global wheat production. Exploring the molecular mechanism of wheat response to drought stress have great significance in wheat molecular breeding. Circular RNAs (circRNAs) have been proved to play an important role in the process of plants tolerance to environmental stresses. Therefore, identifying circRNAs involved in drought stress response will help to construct a regulatory network of wheat drought tolerance, and lay a foundation for analyzing the drought resistance mechanism in wheat. 【Method】In this study, two wheat varieties (Zhoumai13 and Jimai38) with significant differences in drought resistance were used and circRNA-seq was performed on their root samples under well-watered and drought conditions. Differentially expressed circRNAs related to drought stress response were screened based on the identified circRNAs and their microRNAs (miRNAs) targets were predicted. Further, potential circRNA-miRNA-mRNA regulatory modules related to wheat drought stress response were constructed according to the expression patterns of miRNAs and their target genes under drought stress. 【Result】A total of 1409 wheat circRNAs were identified, most of which (68.91%) were exonic circRNAs. Only 133 circRNAs were simultaneously identified in both varieties. A total of 239 differentially expressed circRNAs were identified under drought stress, of which 138 circRNAs were specifically differentially expressed in the drought-resistant variety Zhoumai 13 (ZM13), and 19 circRNAs were differentially expressed simultaneously in both varieties. Besides, 34 targeted miRNAs and 1408 miRNA target genes were predicted. Based on the expression patterns of these differentially expressed circRNAs, targeted miRNAs, and miRNA target genes, five potential circRNA-miRNA-mRNA regulatory modules centered on tae-miR9664-3p, tae-miR1122b-3p, tae-miR9662a-3p, tae-miR6197-5p and tae-miR1120c-5p in response to drought stress were screened. 【Conclusion】Wheat circRNAs have obvious specificity in different cultivars and different expression patterns among different drought-tolerant wheat cultivars. A total of 239 wheat circRNAs and five potential circRNA-miRNA-mRNA regulatory modules in response to drought stress were identified in the present study.

【Objective】It was found that there were significant genetic differences between Chinese and European Brassica napus lines, and the yield advantage of hybrid F₁ was obvious. To explore the effect of gibberellin (GA) on the growth and development of B. napus, the dynamic changes of GA during the developmental process of B. napus from different lines were measured. For explaining the role of GA in the formation of yield, the transcriptional levels of key enzyme genes involved in GA synthesis were analyzed, and the relationship between GA content and yield in parents and F₁ was clarified.【Method】The dynamic changes of GA content in B. napus lines (15 Chinese lines and 15 European lines) with different sources from November 2020 to May 2021 were determined using high performance liquid chromatography. Two F₁ hybrid lines (YG2009×YC4, ZS11×YC4) with strong heterosis and their parents were used as materials to investigate the changes of GA content in different periods (D1, 15 January 2022; D2, 15 February 2022; D3, 15 March 2022) and measure growth indicators (plant height, root length, fresh weight, etc.), yield and component factors (silique number per plant, seed number per silique and thousand-seed weight), as well as photosynthetic indicators (photosynthetic rate, stomatal conductance, transpiration rate and intercellular CO₂ concentration). The change trend of GA content with temperature and the relationship between GA content and agronomic characters, photosynthetic characteristics and yield of parents and F₁ hybrid from November 2021 to May 2022 were analyzed. Besides, the transcriptional levels of key enzyme genes involved in GA synthesis of the parents and F₁ at different stages (D1, D2, D3) also examined by quantitative real-time PCR.【Result】The content of GA was closely related to the ambient temperature, and the GA content in the tested B. napus lines decreased first and then increased with the change of temperature. However, it was found that the average content of GA in B. napus lines from Europe was higher than that of Chinese lines. F₁ showed significant yield heterosis. Compared with the male and female parents, the yield of YG2009×YC4 and ZS11×YC4 increased by 18.06% and 10.35%, and 29.92% and 28.6%, respectively. There were significant differences in agronomic traits between parents and F₁, and the yield was correlated with GA content. The results also showed that the transcriptional levels of GA20ox4, GA3ox2 and SLR1 in parents and hybrid F₁ varied greatly.【Conclusion】The GA content of B. napus lines from Europe was more sensitive to temperature changes, but its average content of GA was higher than that from China. The yield of F₁ between European rape and Chinese rape lines showed strong heterosis, which was correlated with GA content. The transcriptional levels of GA20ox4 and GA3ox2 regulated the GA content.

【Objective】To study the apparent matrix effect of yeast polysaccharide (YP) from S. cerevisiae on the hydrolysis of fruity ester and explore the potential application of yeast polysaccharide in stabilizing wine aroma profile and expand shelf life of product. 【Method】YP was extracted from S. cerevisiae by hot water extraction and alkali methods, and the basic components of YP were analyzed by UV spectrophotometer, GC and HPLC. The model wine containing the conventional concentration of fruity esters was prepared and treated with YP, and the concentration of YP was set in the range of 0—2.0 g.L^-1. The effect of YP on the volatility of fruity esters was analyzed by the static headspace method. Next, model wines with different treatments were stored at 4°C for 6 months, and the content of fruity esters in model wine was regularly monitored. Finally, sensory analysis was used to evaluate the aroma notes of model wine stored 6-months. 【Result】Instrumental analysis showed that the total polysaccharide content of YP is (72.61±3.29)%, and the protein contents accounts for (11.20±0.02)%. The main monosaccharide composition of YP is mannose and glucose, and their molar ratio is 1.790:1. Molecular weight of YP is 576 Da, 18 kDa, 163 kDa and 21819 kDa. Static headspace analysis indicated that YP treatment could reduce the volatility of acetate esters in model wine, especially 0.8 g?L^-1. While YP treatment could increase the volatility of ethyl esters. Data of regular sampling found that the hydrolysis rate of ethyl esters was significantly higher than that of acetate esters during 6 months storage. Compared with the control, 0.4-0.8 g?L^-1 YP slowed down the hydrolysis of acetate esters and ethyl esters by 10%—40% and 3.7%—26.7%. Sensory analysis showed that model wine added with YP showed higher MF% of temperate sour and sweet fruity，preserved fruit and floral aroma notes of wine samples compared with the control. 【Conclusion】From the study of model wine system, it was concluded that adding 0.4—0.8 g?L^-1 YP during wine storage slowed down the hydrolysis of fruity esters, stabilized wine fruity aroma profile and showed potential application value for prolonging wine shelf life.

【Objective】The effects of deep tillage under continuous rotary tillage on growth dynamics, photosynthetic matter production and yield formation of different japonica rice were studied in order to provide technical support for high yield and high efficiency cultivation of high quality japonica rice in cold regions. 【Method】A field experiment was conducted in 2018-2019, under the condition of straw returning to the field, on the basis of rotary tillage in the previous stubble for two consecutive years. Here, two tillage practices, namely, deep tillage and rotary tillage were adopted during the growth stages of three modern japonica varieties Suijing18, Kendao12, and Sanjiang6. The effects of deep tillage and rotary tillage on the growth dynamics and post-anthesis production characteristics of high-quality japonica rice were studied. 【Result】There was no significant difference in yield between years, but tillage methods had significant effects on the growth and development, photosynthetic dry matter production characteristics and yield characters of high-quality japonica rice in cold regions. Compared with rotary tillage, deep tillage significantly increased the number of tillers per square meter and the number of effective panicles, the flag leaf unfolded later and lasted longer, and the heading was late but the duration did not change. The biomass and dry matter transport capacity of stem and sheath increased, and the biomass and stem-sheath dry matter transport capacity were increased by 8.34% and 5.36% respectively at full heading stage. The output, output rate and transformation rate of stem and sheath matter increased by 13.19%, 6.70% and 9.17% respectively (P<0.05). It increased the leaf area index at full heading and mature stage, prolonged the duration of green leaf area and increased the population growth rate. The internode length, leaf length and width of the third and fourth nodes of the main stem were increased, plant height and ear length were increased, the number of grains per ear and grain weight per ear increased by 7.05% and 3.37% respectively, the harvest index increased by 1.90%, and the average yield increased by 12.78%. Under the same tillage method, Kendao12 was the best in tiller number, photosynthetic matter production capacity, stem and sheath dry matter accumulation and transport capacity, yield and its composition, followed by Suijing18, while Sanjiang6 had higher leaf area index after anthesis, grain number per panicle and grain weight at mature stage, but could not make up for its low dry matter transport capacity, effective panicle number and 1000-grain weight. In terms of interaction effect, the combination of deep tillage × Kendao12 treatment showed higher effective panicles per square meter, strong production and transport capacity of photosynthetic matter after anthesis, high grain-leaf ratio and population growth rate, high 1000-grain weight and harvest index, reasonable allocation of plant agronomic morphological characters and coordination of yield traits, which could achieve a yield increase of 9.15%-27.47%.【Conclusion】Continuous rotary tillage combined with one-year deep tillage is the most effective and sustainable rice tillage system to improve the yield of high-quality japonica rice in this region.

【Objective】 Paratuberculosis is listed in the must-report at the list of OIE diseases, infections and Invasion by the World Organization for Animal Health (OIE). It is classified as the second kind of animal disease in China. It causes chronic and proliferative enteritis in many ruminants. Infected animals become a continuous source of infection in farms through intestinal intermittent excretion, which has brought great economic losses to aquaculture. The pathogen of Mycobacterium avium subsp. paratuberculosis (MAP) belongs to intracellular parasitic Gram-positive bacteria, and is a third group of zoological pathogenic microorganisms, including type C (also designated as type II) and type S. Type C also includes type B. Type S can be further subdivided into sub-group types I and III. And sub-lineages of camelid isolates Studies have shown that each subtype of MAP has no host specificity, but is regional. Inner Mongolia is the first region of the disease in China. It is of great significance to obtain and accurately identify the subtype and genetic characteristics of MAP strains in Inner Mongolia for the prevention and control of paratuberculosis. 【Method】 28 MAP-positive sheep disease samples collected in Inner Mongolia were isolated and cultured by MAP, and the colonies were stained with Ziehl-Neelsen. The positive bacteria were propagated and the genomic DNA was extracted. IS900 gene, IS1311 gene and DMC gene were amplified, sequenced and analyzed. The PCR products of IS1311 gene were identified by Hinf I and Mse I double digestion. 【Result】 28 samples were cultured for 7 - 12 weeks, a total of 9 mediums grew colonies, the colonies were translucent milky white, smooth surface. Single colonies were selected for acid-fast staining, and irregular (single or branched), red-stained Brevibacterium was observed under the microscope, which was consistent with the morphological characteristics and acid-fast staining characteristics of Mycobacterium. The PCR products of IS900, IS1311 and DMC genes of 9 isolates were consistent with the expected size of the target gene fragment. 9 isolates were identified as MAP strains, named MAP-NM1 to MAP-NM9. DMC gene amplification product size of 310bp, consistent with type II MAP characteristics. IS1311 gene amplification products were digested by Hinf I and Mse I restriction endonucleases, and 4 target bands were obtained in 9 strains of MAP, which were consistent with type II MAP. The sequencing results of IS1311 gene and the analysis of MAP representative strains of type I, type II, type III, Indian Buffalo and American Buffalo showed that the nucleotide sites at positions 64, 65, 68, 223, 236, 422, 527 and 628 of the nine MAP IS1311 gene fragments conformed to the characteristics of type C and type B MAP. Sequence analysis of IS900 gene sequencing results showed that the 169th and 216th nucleotides of the nine MAP IS900 gene fragments were C (cytosine) and A (adenine), and accord with Type II and type III MAP. The phylogenetic tree of 17 MAP IS900 gene reference sequences from GenBank database with 9 isolates in this study showed that the 9 isolates in this study were all in the type II MAP branch. Blast online analysis was performed on the sequencing results of the three genes. The reference sequences with the highest homology with the isolates obtained in this study were all type II MAP, and the homology was higher than 98%. In conclusion, all the 9 MAP isolates were type II MAP. 【Conclusion】 To the best of our knowledge, this is the first isolate of the MAP type Ⅱ strains in sheep in Inner Mongolia. 

【Objective】This paper evaluated comprehensively early maturity upland cotton varieties in northwest inland cotton-growing region of China, and uncovered the evolution rules of the main traits from the breeding cultivars in the region. It provides a useful reference for recommendation and breeding of main cotton varieties in northwest inland region. 【Method】A total of 110 early-maturing upland cotton varieties which were approved in northwest inland cotton-growing region from 1988 to 2021 were applied, and phenotypic identification of 12 main traits related to early maturity, yield, fiber quality and plant architecture was carried out in Dunhuang, Gansu province and Shihezi, Xinjiang production and construction corps in 2020 and 2021, respectively. Clustering analysis, correlation analysis and principal component analysis were respectively used to evaluate the phenotypic characteristics of the cultivars, and carry out the breeding evolution analysis of their main traits. 【Result】The phenotype value of 12 main traits had large distribution range from 110 early-maturing upland cotton varieties in northwest inland cotton-growing region of China. The variation coefficient in descending order is: fruit branch length (FBL), boll number per plant (BN), boll opening rate (BOR), boll weight (BW), fiber micronaire (FM), fiber strength (FS), lint percentage (LP), fiber length (FL), flowering time (FT), fruit branch angle (FBA), fiber elongation (FE), and fiber uniformity (FU). By cluster analysis, these cultivars were divided into four groups: Ⅰ, Ⅱ, Ⅲ and Ⅳ, which were the population of high fiber quality, early maturity, loose plant type and high yield, respectively. Correlation analysis showed that early maturity was negatively correlated with yield and fiber quality related to traits, while the yield related to traits were positively correlated with the fiber quality traits, and most of them reached significant or extremely significant level. The 12 main traits were simplified into four principal components which had cumulative contribution rate of 66.92%. Based on the comprehensive evaluation results of these varieties by principal components, an excellent cultivar Zhongmian 113 ranked the first in the 110 early-maturing upland cotton varieties with a score of 0.67, which was characterized by early maturity, high yield and excellent fiber quality, and relatively loose plant type. Additionally, it was found that the early maturity character of cotton varieties approved in Gansu province was significantly better than that of varieties approved in northwest inland region and Xinjiang province, and the traits related to yield and fiber quality of cotton varieties approved in Gansu province were significantly lower than those of varieties approved in northwest inland region and Xinjiang province. During the breeding evolution of early maturing upland cotton varieties in northwest of China for more than 30 years, most of the traits related to yield and fiber quality showed significant upward trends, and the plant type was becoming more compact. BN was negatively correlated with BW, LP, FL and FS in early cultivars, while BN was positively correlated with BW, LP, FL and FS in recent cultivars.【Conclusion】In the process of breeding and improvement of early maturing upland cotton varieties in northwest of China, the main traits related to yield and fiber quality had wide distribution, and they had significant improvement trends year by year. In the recently developed varieties, BN, FL and FS had been improved cooperatively. 

【Objective】Flower color is an extremely important ornamental trait of P. mume, and flavonoids are the main pigments in the petals of P. mume. However, there are few systematic studies on the composition of flavonoids, and the relationship between flower color and flavonoids in P. mume. The study on flavonoids can provide reference for the mechanism of flower color formation and the development of flavonoids resources in P. mume.【Method】In this study, the petals of four P. mume cultivars with representative flower color in the blooming stage and the key period of flower color change of two cultivars were selected as materials. It measured the flower color phenotype of petals with the Royal Horticultural Society Color Card (RHSCC) and colorimeter. Flavonoids in those petals of flowers were determined by high-performance liquid chromatography and mass spectrometric (HPLC-MS) detectors. Then, Duncan test and OPLS-DA were used to analyze the difference of metabolites among these four cultivars and the major blooming stages. 【Result】In total, 25 flavonoids were described. The main components of  red Baixu Zhusha and purple-red Huqiu Wanfen wereanthocyanins. But the contents of cyanidin and its derivatives between Baixu Zhusha and Huqiu Wanfen were differences. In addition, from the big budding stage to the blooming stage, the red color of Baixu Zhusha gradually became lighter, and the contents of cyanidin-3-O-glucoside and peonidin -3-O-glucoside also gradually decreased.Yellow-green Bian Lv’e and pure white Sanlun Yudie were most enriched with quercetin and its derivatives. The contents of quercetin derivatives between Bian Lv’e and Sanlun Yudie were differences. 【Conclusion】The flavonoid metabolic profiles differed among the different colored petal, and flavonoids with medicinal value were distributed in all varieties. The difference in the contents of cyanidin and peonidin may be related to  petal color differences of red P. mume. Quercetin derivatives may affect the color of yellow-green P. mume. In this study, the flavonoids metabolites of different color P. mume were identified and analyzed for the first time, and the differences in flower color P. mume varieties and the blooming process were preliminarily understood from the metabolic level. The results provide a reference for understanding the difference of flower color formation and development of flavonoid resources of P. mume. 

【Objective】 Fowl adenovirus (FAdV) circulates in chicken flocks with multiple serotypes, while there is less information about the pathogenicity of all serotype strains. To understand the capability of causing disease as a primary pathogen to chicken of the FAdV-8a strain, we carry out the experiment for evaluating the pathogenic characteristics of this serotype strain, which will help making the control strategy for breeding. 【Method】 In 2017, liver tissue was collected form the diseased flocks. The liver tissue homogenates were inoculated into the embryo egg for isolating the virus. The isolate was determined as a FAdV strain after PCR detection. To classify the isolate, genomic sequencing and the genetic evolution based on the complete genome sequence and the hexon gene sequence were performed. To clarify the pathogenicity, thirty 10-day-old SPF chicks were randomly divided into 2 groups and exposed to the isolate JL/170408 via nasal inhalation and eye droppings. The clinical syndrome (including morbidity and mortality), viremia, virus shedding, circulating antibody, postmortem examination and histopathological detection at 5 days post infection (d.p.i.), viral distribution and the tropism on tissues were performed to evaluate the pathogenic capability and characteristics of JL/170408 to SPF chicks. 【Result】 The complete genome sequencing showed that there were the highest identity between the isolate and the FAdV-8a TR59 strain. They showed high identity in the genomic structure and the encoding gene. Phylogenetic analysis based on the complete genome sequence, the isolate JL/170408 was in the cluster of FAdV-E, further was grouped into the branch of serotype 8a based on the hexon gene. Consequently, the isolate JL/170408 was determined as FAdV-8a serotype within the species of FAdV-E. The clinical peak was observed from 3 to 13d.p.i. without death. The virus shedding and viremia was detected as early as 3d.p.i. and last for a long period at least 51d, the antibody was not positive conversion completely and the mean ELISA titer S/P<1, which didn’t provide enough neutralizing ability to eliminate the virus in the blood and the intestinal tract. At 54d.p.i., the ELISA titer reached a peak with a mean S/P>2, with the consequence of viremia disappearing and a sudden drop of virus shedding. Postmortem examination and histopathological detection at 5d.p.i. showed no obvious pathologic change. While the viral load was detected in 15 tissues, suggested that the isolate propagated in multiple tissues and exhibited higher tropism to gizzard. By monitoring the circulating antibody, the infected birds showed later antibody positive conversion until 15d post infection. Not all birds showed positive seroconversion even at 51d post infection, and the antibody level was stable. At 54d post infection, the antibody titer reached peak, suggesting that birds may suffer a second infection. Virus neutralization test based on the antiserum of 63d.p.i. showed that there was no obvious correlation between the circulating antibody and the neutralization antibody. 【Conclusion】 The FAdV-8a strain JL/170408 causes disease to 10-day-old chicks as single pathogen without leading to death, the isolate is determined as low pathogenic strain. JL/170408 propagates in multiple tissues with higher tropism to gizzard. The infected chicks show a long duration of virus shedding with a repetitive characteristics.

The new development concept of "innovation, coordination, green, openness and sharing" is the centralized reflection of China's development concept, direction and focus in the 14th Five-Year Plan and even in the longer term. The green development of agriculture is an important part of the implementation of the new development concept, which plays an important role in forming a harmonious coexistence between human beings and nature, ensuring food safety and creating a livable environment. Fertilizer, as the largest exogenous input and production material, plays a significant role and has a profound impact on the quantity and quality of agricultural products and the agricultural ecological environment, and plays a pivotal role in the green development of agriculture. However, the improper application of traditional fertilizers has caused the degradation of soil quality, environmental pollution and degradation of agricultural products, which urgently requires the transformation and upgrading of fertilizer products, and the development of green inputs has come into being. Green fertilizer concept and definition: the application of quality and safety of raw materials, low-carbon environmental protection process, the use of physical - chemical - biological modification and efficiency technology production and use, with efficient and balanced nutrients, emission reduction and environmental protection, fertilization of fertile soil function of a class of fertilizers. Types of green fertilizers are mainly divided into the following five categories: Nutrient-efficient green fertilizers; Carbon-fixing and fertilizing green fertilizers; Efficiency-enhancing and nutrient conversion efficiency green fertilizers; Nutrient-balanced green fertilizers; Value-added green fertilizers. How to realize the green transformation of chemical fertilizers and the efficient and low-cost utilization of organic fertilizer resources, there are four main suggestions. (1) Rely on market mechanisms, strengthen top-level design, and build a new system of green fertilizer manufacturing; (2) Take the integrated management of nutrient resources as the core, and promote the balanced and coordinated development of organic-mass-element-micro-element fertilizers; (3) Fully play the role of scientific research platforms, and greatly develop intelligent green fertilizer products; (4) Integrate modern sensing and information technology to thoroughly promote green and efficient precision fertilization. This paper provides an overview of the background, concept, types and characteristics of green fertilizers proposed, and discusses the future development direction, in order to provide insight into the green transformation of China's fertilizer industry and the green development of agriculture in the future.

【Objective】 Cropping system and nitrogen rate are important factors affecting the growth and yield formation of oilseed (Brassica napus L.). To investigate the effect of nitrogen application on yield formation and nutrient utilization of oilseed under different cropping system. 【Method】 a field experiment was carried out in Huanggang, Hubei province. A oilseed variety “Zhongyouza19” was used as the material, setting with two cropping system (rice-oil rotation, RO; soybean-oil rotation, SO) and four nitrogen rate (N0, 0; N1, 90 kg·hm^-2; N2, 180 kg·hm^-2; N3, 270 kg·hm^-2) in this study. Yield and its components, dry matter accumulation, agronomic traits, nitrogen content and seeds quality were measured. 【Result】(1) the seed yield of SO was significantly higher than that of RO, and the pods per plant, seeds per pod and 1000-seeds weight of oilseed in different cropping system all tended to increase significantly by increasing the amount of nitrogen. Compared with N0, the seed yield of RO increased by 176.68%, 436.49% and 835.40% under N1, N2 and N3 treatments, respectively, while that of SO increased by 123.96%, 344.46% and 547.25%. And the seed yield increased by 62.09%, 31.33%, 71.79% and 12.21% under N0, N1, N2 and N3 treatments, respectively, in SO compared to RO；(2) The root crown diameter, plant height, first effective branch height and branch number of SO rape were significantly higher than those of RO at maturity stage, and the increase in each agronomic trait index were significant under different cropping system with the increase in nitrogen application; the root biomass and above-ground biomass of SO were significantly higher than those of RO at all growth stages, but the root shoot ratio was lower than that of RO. the root shoot ratio decreased significantly after seedling stage in both cropping system with increasing nitrogen application. (3) Nitrogen content and nitrogen accumulation in the root, pod shell, stalk and seeds of SO were higher than those in RO, and the increase in nitrogen content and nitrogen accumulation in each part were significant with the increase in nitrogen application; the apparent nitrogen recovery efficiency under SO were higher than those under RO, and the apparent nitrogen recovery efficiency under RO increased with the increase in nitrogen application. (4) Compared with the RO, the soluble sugar content of pod shell under SO was lower, while the amino acid content and amino acid /soluble sugar content were higher with the same nitrogen application. The soluble sugar content decreased, but the amino acid content and amino acid/soluble sugar content increased with the increase of nitrogen application. Therefore, the oil content of oilseed in SO was lower than that in RO due to the limitation of fatty acid synthesis substrate, and the oil content of seeds decreased significantly with the increase of nitrogen application in cropping system. Oil yield was maximum in both cropping system at 270 kg·hm^-2 nitrogen application level, 1 678.60 kg·hm^-2 and 1 665.33 kg·hm^-2 for RO and 1 684.03 kg·hm^-2 and 1 687.10 kg·hm^-2 for SO respectively, but the difference in oil yield between 180 kg·hm^-2 and 270 kg·hm^-2 nitrogen application for SO was not significant. 【Conclusion】In conclusion, the nitrogen rate for RO can be controlled at about 270 kg·hm^-2, but the nitrogen rate for SO can be controlled at about 180 kg·hm^-2 to ensure higher nitrogen use efficiency and higher oil yield.

【Objective】This study aimed to establish a comprehensive evaluation model in fruit quality, clarify the comprehensive grade of fruit quality and their corresponding meteorological characteristics from different Newhall Navel orange (Citrus sinensis [L.] Osb. cv. Newhall) orchards in China, and provide a reference for the ecological environment adaptability and suitable planting. 【Methods】Twenty three Newhall orchards in different ecological environments of China were selected to measure fruit external and internal quality indicators. Correlation analysis, principal component analysis and cluster analysis were used to identify the core indicators, and the comprehensive evaluation models of fruit quality were established by analytic hierarchy process (AHP), principal component analysis (PCA) and fuzzy comprehensive appraisal (FCA), respectively. The optimal algorithm model and fruit grade classification threshold were determined and verified with sensory quality evaluation. Meanwhile, the comprehensive quality grades 

and the characteristics of corresponding ecological factors of Newhall navel orange fruit from different producing areas were explored. 【Results】The fruit comprehensive quality of 23 Newhall orchards showed obvious regional characteristics. The fruit in southern Jiangxi and southern Hunan have higher total soluble solid and solid acid ratio, while the fruit in western Hunan and the upper and middle reaches of the Yangtze River have better fruit external color indexes and higher titratable acid. The quality indexes are correlated to varying degrees. Five core indexes were selected by principal component analysis combined with cluster analysis, including comprehensive color index, fruit weight, soluble solids, solid acid ratio and vitamin C content. At the same time, AHP model was determined as the comprehensive evaluation model of fruit quality with the best fitting degree of sensory quality index: Y (comprehensive value) = 0.06× comprehensive color index + 0.26× single fruit weight +0.16× soluble solid content +0.42× solid acid ratio +0.11× vitamin C content (standardized value). The comprehensive fruit quality indicators of different Newhall orchards were ranked, and the classification threshold was determined as follows: ≥0.60 was the first—class orchards, mainly concentrated in southern Jiangxi, southern Hunan and eastern Guangdong, with active accumulated temperature, effective accumulated temperature, maximum sunshine hours and surface temperature; 0.45—0.60 was the second—class orchards, mainly concentrated in northern Guangxi and western Fujian, characterized by higher temperature accumulation and rainfall; 0.30—0.45 was the third—class orchards, mainly concentrated in western Hunan and the middle and upper reaches of the Yangtze River, with relatively lower rainfall and temperature accumulation; <0.30 was the fourth—class orchards, mainly distributed in southern Zhejiang, with the highest rainfall. 【Conclusion】The core indicators of the comprehensive quality of citrus fruits were identified by PCA, and the AHP model with the optimal for the Newhall fruit comprehensive evaluation by combining the eigenvalues of each principal component to achieve automatic assignment of AHP judgment matrix. The ecological factors of different grades of orchards were significantly different. These results provide algorithms and data support for the development of the decision system based on " suitable planting "of citrus varieties in different ecological environment.

【Objective】Grape berry size is one of important factors affecting grape appearance and the final productivity. It is a complex quantitative trait regulated by multiple genes. Mining the key genetic regulatory loci and the underlying genes for berry size related traits will help to improve grape yield. 【Method】In this study, 150 diverse grapevine varieties were selected as materials. The berry weight, seed number per berry, and seed weight were measured in 2019 and 2020, respectively. Based on high-density genotype data obtained by resequencing, the genome-wide association studies (GWAS) were carried out to detect significantly associated SNPs and predict important candidate genes.【Result】The three measured traits exhibited extensive phenotypic variation with 39.55%-68.89% of phenotypic variation coefficients; The phenotypic distribution of the observed three traits in the population showed continuous quantitative genetic characteristics; A significant positive correlation between each trait were observed in two years; Based on the phenotypic data collected in two years, a total of 150 significant SNPs were detected for berry weight. In 2019, 99 SNPs were detected, each of which contributed the phenotypic variation from 14.48% to 25.59%; In 2020, 73 SNPs were detected, explaining 16.08%-26.83% of phenotypic variation; Among these SNPs, 24 were detected repeatedly in both two years, mainly located on chromosome 1, 5, 11 and 16. Compared with the trait of berry weight, less SNPs significantly associated with the seed number were detected. A significant SNP was detected in 2019, and the phenotypic explanation value was 24.29%; In 2020, 17 significant SNPs were detected, which all located on chromosome 18; 1 and 2 SNPs located on chromosome 18 significantly associated with seed weight were detected respectively in 2019 and 2020, accounting for 23.59%-48.29% of phenotypic variation. Within the genomic region of SNPs detected repeatedly for two years, 11 candidate genes that may be related to berry weight were screened out based on the functional annotation, including ethylene signal pathway genes (VIT_05s0049g00490, VIT_05s0049g00500, VIT_05s0049g00510 and VIT_16s0100g00400), gibberellin signal pathway genes (VIT_11s0016g04630 and VIT_16s0022g02310), auxin responsive protein gene (VIT_11s0016g05640) and some important transcription factor genes (VIT_05s0049g00460, VIT_11s0016g05660 and VIT_16s0022g02330). A candidate gene VIT_18s0041g01880 (encoding a MADS box protein VviAGL11) associated with seed content was identified on chromosome 18, and different SNP genotype on this gene significantly affected the grape berry seed number and weight. 【Conclusion】A total of 150 SNPs significantly associated with berry weight were detected in two years, mainly located on chromosomes 1, 5, 11 and 16; A total of 19 significant SNPs associated with seed content were detected, mainly located on chromosome 18. Based on the results of gene annotation and genotype analysis, 11 candidate genes that may be involved in the regulation of grape berry weight including VIT_11s0016g04630 and VIT_16s0022g02310 were selected; the candidate gene VIT_18s0041g01880 was determined significantly correlated with seed content.

【Objective】This study explored the differences and causes of oat lipase activity of different varieties. Providing a theoretical basis for screening varieties with low lipase activity and achieving stable enzyme inactivation effect of oat products. 【Method】Six main varieties of three main oat planting regions were selected for the study, and their lipase activity, nutritional indexes, physical traits, and agronomic indexes were measured. To answer the differences in lipase activity of oat varieties, the indicators significantly related to oat lipase were screened by correlation analysis. Through cluster analysis, classified multiple oat samples by lipase activity. Transform data having correlations into composite variables for statistical analysis by principal component analysis. To derive a predictive model for lipase activity, an analytical method combining gray correlation and multiple stepwise regression was used. The indicators correlating with lipase activity were used as independent variables, and the lipase activity was used as dependent variables for quantitative model fitting. 【Result】Lipase activity was significantly positively correlated with crude fat content (r=0.32, p<0.05), and the various trends of fat content, unsaturated fatty acid content, lipase activity, and acid value were consistent. Lipase activity was significantly positively correlated with crude protein content (r=0.46, p<0.01), and the higher lipase activity was, the higher percentage of electrophoretic bands located in 31-43 kD were. It was significantly negatively correlated with grain test weight (r=-0.71, p<0.01) and positively associated with growth period (r=0.37, p<0.01). Baiyan 18 and Diyan 1 were low lipase activity and high nutrition varieties according to grey relational analysis, and the relevance value with ideal variety X₀ were 0.951 and 0.883, respectively. Stepwise regression analysis only retained the test weight and protein content as independent variables. The prediction model of lipase activity was established as Y=720.274－2.255×test weight (g·L^-1)+75.761×protein content (%), p<0.01, R² = 0.658.【Conclusion】The varieties had significant effects on oat lipase activity. Protein content, fat content, test weight, and growth period were the main influencing factors of oat lipase activity. Grey relational analysis combined with stepwise regression analysis could be used to comprehensively evaluate oat varieties effectively and quickly select varieties with low lipase activity.

【Objective】In this study, the purpose was to comprehensively evaluate the cold tolerance of cotton varieties (lines) at the seeding stage, establish a reliable evaluation model, screen and identify indicators, and provide a simple and effective evaluation method for the selection and identification of cold-tolerant varieties in cotton.【Method】200 upland cotton varieties (lines) were used to test hypocotyl length, root length and 100-grain weight, etc. under three treatments of constant chilling (CC), diurnal variation of chilling (DVC) and normal conditions. A combination of integrated cold tolerance coefficient difference analysis, frequency analysis, drop analysis, principal component analysis, cluster analysis, and multiple regression analysis were used to classify their cold tolerance types, establish cold tolerance prediction models, and screen evaluation parameters. 【Result】The variation of each parameters at normal conditions were minor fluctuations ranging from 3.12% to 18.89%. The seedling emergence rate was above 85.00%, which had high viability and could be used for subsequent cold tolerance analysis. The variability of each parameters within the accessions increased under chilling stress, ranging from 7.14%-108.33%, and the most variable parameter were root length under CC condition and germination index under DVC condition. Principal component analysis converted the 14 parameters under chilling stress and 100-grain weight measured into six mutually independent composite indicators, representing 74.98% of the total data information. The comprehensive cold tolerance evaluation value (D) was calculated by the affiliation function method and then clustering analysis was performed. 200 cotton varieties (lines) were divided into five categories according to their cold tolerance, with 2 of the group Ⅰ being strongly cold tolerant, 42 of the group Ⅱ being cold tolerant, 69 of the group Ⅲ being medium cold tolerant, 83 of the group Ⅳ being more sensitive, and 4 of the group Ⅴ being sensitive, of which Xinluzhong 16 was the most cold-tolerant material. A multiple regression analysis was applied to establish a prediction model for cold tolerance of cotton at seedling emergence as Y=-4.10+0.58X4+0.40X14+0.32X1+0.22X5 (R²=0.92), and four parameters for cold resistance evaluation were confirmed, namely total length, emergence rate, and dry matter weight under CC stress, germination rate under DVC stress. The cold-tolerant varieties (lines) had higher seedling emergence rates of early sowing experiment in the field, which were basically consistent with the results of the indoor results. 【Conclusion】It is feasible to use CC and DVC stress combined with multivariate statistical analysis to evaluate the cold tolerance of cotton at seeding stage, and total length, emergence rate, and dry matter weight under CC stress, germination rate under DVC stress can be used as evaluation parameters.

【Objective】With global warming, high temperature has an increasing impact on food crop safe. Excavation of heat tolerance gene resources is the most direct green ecological method to cultivate new varieties of heat resistance and eliminate the harm of high temperature, which also the basis for clarifying the physiological, biochemical and molecular genetic mechanism of heat tolerance.【Method】Establishing the identification and evaluation method of heat tolerance at seedling stage, a set of RIL populations was structured from the extreme heat-tolerance Ganzaoxian58(GZX58) and heat-sensitive Junambyeo (JNB), and then the high density genetic map was constructed using genotyping by resequencing technology. To converting SNP information into Bin genotype of the RIL population using sliding window method, which predicting the recombination breakpoints on the chromosomes, finally a high density BinMap genetic map was constructed. Based on the genotype and phenotype data of the 171 lines, QTL mapping of the high temperature seedling survival rate (HTSR) and heat tolerance class (HTC) was performed by ICIM method of the QTL IciMapping software.【Result】A high-density genetic map containing 3,321 Bin markers was constructed, the number of Bin markers for each chromosome between 159 and 400, the average physical distance two markers was about to 106 kb; heat tolerance of the parents and RIL populations was identified by stepwise heat stress at seedlings stage, there have a significant negative correlation between HTSR and HTC, in addition, there has a significant positive correlation between HTSR and indica gene frequency (Fi), which the higher of the Fi, the heat tolerance is better; the bi-modal continuous distribution of phenotype traits from the RIL population showed that the heat tolerance is regulated by few major QTL. A total of 12 QTL controlling with heat tolerance at seedling stage, there have 8 and 4 QTL regulating for HTSR and HTC, respectively. There has a significant genetic overlap from HTSR and HTC, qHTS2, qHTS7 and qHTS8, three major QTL cluster play an important role in regulating the heat tolerance at seedling stage. Among these QTL, qHTS7 was a novel major QTL cluster, which has a strong effect on enhancing the heat resistance at seedling stage. 【Conclusion】We constructed a high density genetic linkage map containing 3,321 Bin markers, which be used to analyzed the heat tolerance gene from the GZX58 at seedling stage, there have three key QTL cluster identified associated with the heat tolerance, a novel QTL cluster qHTS7 was discovered, efficient acquisition of target segments and candidate genes based on high-density genetic mapping, eight key candidate genes were selected by bioinformatics for regulation of the heat tolerance.

【Objective】This study is to excavate embryo-related quantitative trait loci (QTL) with potential breeding value, to explore the genetic relationship between embryo and other agronomic traits in tetraploid wheat, and finally to aim at laying an important foundation for the fine mapping and breeding utilization of embryo-related traits in the future.【Method】A total of 121 F₈ recombinant inbred lines (RIL) constructed by crossing tetraploid durum wheat (Ailanmai) and wild emmer wheat (LM001) were used. This RIL population was planted in five different environments including Wenjiang (2018-2020), Chongzhou (2020), and Ya'an (2020) in Sichuan Province for phenotypic evaluation of embryo length (EL), embryo width (EW), embryo length/embryo width (EL/EW), embryo length/kernel length (EL/KL), embryo width/kernel width (EW/KW), and embryo area (EA). QTL mapping was performed based on a genetic linkage map constructed based on the wheat 55K SNP. 【Result】 The embryo size-related traits showed approximately normal distribution in the RIL population satisfying the genetic characteristics of quantitative traits. A total of 27 QTL for embryo size-related traits were detected in five environments over three years. Among them, seven ones controlling EL could contribute 11.88 % to 18.99% of phenotypic variation. Seven QTLs controlling EW could explain 21.77 to 29.41% of phenotypic variation. Five stable and major QTLs (QEL.sicau-AM-3B, QEW.sicau-AM-2B, QEW/KW.sicau-AM-2B, QEL/EW.sicau-AM-2B-1 and QEA.sicau-AM-2B) were identified, and they explained 11.88% to 18.99%, 21.77% to 29.41%, 8.80% to 24.92%, 12.79% to 25.69% and 10.47% to 15.22% of phenotypic variation, respectively. In addition, four QTL-rich regions were identified in the embryo size-related loci mentioned above. The QTL controlling EL/KL and EL was located on chromosome 1B, that for EW, EL/EW, EW/KW, and EA was located on 2B, that controlling EL and EA was on 3B, and that controlling EL/EW and EW/KW was on 6B. Embryo size was significantly and positively correlated with kernel size. Further, the major QTL for EL, QEL.sicau-AM-3B was co-located with that for kernel length identified previously, but that for EW QEW.sicau-AM-2B was independent of that for kernel width. Four genes likely involved in regulation of embryo size were identified in intervals where major QTL were mapped. 【Conclusion】Five stable and major QTLs were identified: QEL.sicau-AM-3B, QEW.sicau-AM-2B, QEW/KW.sicau-AM-2B, QEL/EW.sicau-AM-2B-1, QEA.sicau-AM-2B, among which QEW.sicau-AM-2B may be novel.

【Objective】Sugarcane leaf scald disease is an important bacterial disease affecting sugarcane yield. Selection of disease-resistant genotypes can effectively reduce the incidence of this disease. This study aimed to explore the leaf-scald resistance of sugarcane genotypes, standardize resistance evaluation method, and provide a basis for the selection and utilization of germplasm resources of sugarcane. 【Method】Xanthomonas albilineans JG43 isolated from Guitang 46, was used as inoculum on 70 sugarcane genotypes using the decapitation method by placing 500 mL of bacterial suspension on the surface previously cut above the apical meristem with scissors dipped in the inoculum suspension of 10⁸ CFU/mL. The disease incidence (IC) was calculated at 14, 28, 42, 56, and 70 days post-inoculation (Dpi). The disease index (DI) and the area under the disease progress curve (AUDPC) were calculated according to the disease severity of leaf scald in sugarcane. Variance, principal component, and discriminant analysis were performed using SPSS 25.0 software. Among them, a general linear model procedure (PROC) and the square sum model of type III were used to analyze the variance, with IC, DI and AUDPC as dependent variables, genotype, block and days post-inoculation as fixed factors. After the original data were processed by standardization (Z-score), principal component analysis was carried out by KOM and Bartlett sphere test. The Euclidean metric was calculated for cluster analysis using the WPGMA method of DPS 9.50 software. The discriminant analysis was performed to evaluate the clustering results according to Fisher's criterion. 【Result】Some genotypes displayed white pencil lines at 14 dpi, then gradually expanded to the edge at 28 dpi. The leaves began yellowing or albinism from the edge to the veins at 42 dpi, then curled inward and died at 56 dpi. The severely infected plant withered and eventually died at 70 dpi. Variance analysis exhibited highly significant effects for IC, DI, and AUDPC among genotype (Gen), days post-inoculation (Dpi), and their interactions effect (Gen × Dpi) (P<0.01). Approximately 42% of the total sum of square was attributed to Dpi effect, followed by Gen × Dpi and Gen effects, indicating significant differences among genotypes resistance across the days post-inoculation. At 56 dpi, the disease reached a steady plateau, and the data in this period could be better divided among sugarcane genotypes. The results of discriminant and cluster analysis showed that 70 genotypes were divided into five different groups, including 15 highly resistant, 14 resistant, 15 moderate, 11 susceptible, and 15 highly susceptible genotypes. 【Conclusion】The resistance of sugarcane genotypes to leaf scald was assessed using the decapitation method, the IC, DI and AUDPC at 56 dpi were used as the evaluation indicators. The combined method of clustering and discriminant analysis could improve the accuracy of clustering results. Fifteen genotypes of high resistance to leaf scald were assessed and used for the sugarcane breeding program in China, including Zhongzhe 9, Zhongzhe 4, Zhongzhe 2, GUC19, GUC8, Yunrui 03-103, Yunrui 05-649, Yunrui 05-182, Yunrui 05-367, Yunrui 89-159, Funong 11601, Funong 09-4059, Guitang 02-467, Guitang 08-297, ROC22.

【Objective】Understanding the decomposition, nutrient release characteristics and driving factors of straw under different C/N ratio based on coal mining area could provide theoretical basis for the full utilization of straw resources and reclaimed soil fertility improvement.【Method】Air-dried maize straw and wheat straw cut into 2 mm pieces were selected for decomposition experiment of a coal mining reclamation area in Shanxi province. Two C/N ratio levels of 25 and 10 were designed in maize straw and wheat straw by supplementing urea, taking no nitrogen application that C/N ratio levels was 52 and 74 as the control. All the straws (8g in organic carbon) were put into a nylon mesh bag (0.38 μm aperture), and horizontally buried into 15cm deep of soil. On the 12, 23, 55, 218, 281 and 365 days since buried, samples were collected from the bags to analyze the dynamic of the dry matter residue and nutrient (carbon, nitrogen, phosphorus and potassium). 【Result】During the first 55 days, adjusting the C/N on 25 with the application N was the best way to accelerate the decomposition of maize straw. And adjusting the C/N on 10 was the best way to accelerate the decomposition of wheat straw. Application N could significantly promote the release of carbon and phosphorus from maize straw during the first 55 days. Application N could significantly accelerate the release of carbon, nitrogen and phosphorus from wheat straw, but had no significant effect on the release of potassium. The thermal equation of straw decomposition and nitrogen and potassium release was better than the temporal equation, and phosphorus release from straw was not suitable for the exponential decay equation. When the accumulated temperature was 4 600℃, the average release rates of carbon, nitrogen, phosphorus and potassium from straw were 49.2%, 39.5%, 40.8% and 9.3%; When the accumulated temperature reached 1 125℃, more than 85% the potassium of straw was released. The decomposition of straw was mainly influenced by the temperature, organic carbon, lignin and hemicellulose. 【Conclusion】Application N could accelerate the decomposition of maize straw and the release of carbon and phosphorus in the early stage, and application N could significantly accelerate the wheat straw decomposition and the release of carbon, nitrogen and phosphorus. Temperature could better reflect the process of straw decomposition and nitrogen, potassium release than time, the decomposition of straw was mainly regulated by the temperature, organic carbon, lignin and hemicellulose. Therefore, combined with the hydrothermal conditions in the coal mining area, the straw with an appropriate amount of urea should be returned to the field in the right time to improve the content of nitrogen, phosphorus and potassium of the reclaimed soil.

【Objective】To clarify the effects of long-term no-tillage and mulching measures on soil aggregate structure and organic carbon content in Weibei dry plateau farmland, and to explore suitable tillage measures to improve the regional soil.【Method】On the basis of continuous 16-year field positioning experiments, traditional tillage (CT), no-tillage and no mulch (NT), no-tillage + straw mulch (NS), no-tillage + plastic film mulching (NP), no-tillage + A total of 5 field management measures, including straw + plastic film mulching (NSP), were used. The 0-40 cm ring knife and profile soil samples were collected during the spring corn harvest in October 2019, and the bulk density, aggregate particle size distribution and organic carbon content were determined.【Result】(1) No-tillage and mulching measures (NT, NP, NS and NSP) affected the bulk density and aggregate size distribution of Heilu soil. No-tillage and mulching measures both increased the soil bulk density of the plough layer, of which 0-10 cm increased significantly (6.8%-17.8%). The changes of bulk density and porosity of the plough layer were opposite to those of the plough layer. The proportion of micro-aggregates was significantly reduced, which promoted the transformation of micro-aggregates into macro-aggregates. The weight percentage of aggregates of each particle size in the plough layer (0-20 cm) is distributed as follows: larger aggregates (0.25-2 mm) > large aggregates (>2 mm) > micro aggregates (0.053-0.25 mm) > powder. The clay fraction (<0.053 mm), the larger aggregates and silty clay fractions in the plow bottom layer (20-40 cm) were significantly higher than the macroaggregates and microaggregates. (2) Under no-tillage and mulching measures, the organic carbon content increased with the increase of aggregate particle size. In the 0-40 cm soil layer, the organic carbon content of the aggregates of each particle size in the NT treatment was significantly lower than that in the CT treatment, while the NS and NSP treatments were significantly higher than those in the CT treatment. (3) The particle size distribution of aggregates is the dominant factor causing the change of the nutrient contribution rate of aggregates. The total organic carbon accumulation in the plough layer is dominated by aggregates >0.25 mm, and the plough layer is mainly composed of silty clay components and organic carbon in larger aggregates main. 【Conclusion】Long-term no-tillage and mulching measures promote the transformation of micro-aggregates into macro-aggregates in the plough layer. Compared with traditional tillage, no-tillage and plastic film mulching decreased the organic carbon content of aggregates of various particle sizes in Heilong soil and in the plough layer, respectively. However, no-tillage mulching (NS, NP and NSP) increased the organic carbon content of aggregates of each particle size compared with no mulching. Straw mulching alone had the best effect, and significantly improved the bulk density and aggregate particle size distribution, which was the best treatment.

【Objective】 The aims of the study were to analyze the genes involved in the regulation of grape anthocyanin accumulation and fruit quality by 24-Epibrassinolide under high-temperature stress, and to explore the molecular mechanism of EBR regulation anthocyanin accumulation in grapes under high-temperature stress. 【Method】 'Cabernet Sauvignon' grapes were treated with high-temperature stress using infrared emitter, and sprayed 0.6 mg?L^-1 of EBR before the veraison. The contents of total anthocyanins, total sugar, reducing sugar and sucrose were quantified using the ultraviolet visible spectrophotometer. The mechanism of EBR-mediated accumulation of anthocyanin under high-temperature stress was analyzed by transcriptome sequencing. 【Result】 Starting from veraison , the anthocyanin content increased gradually under various treatments. At maturity, the total anthocyanin content in the high temperature group (HT) was significantly lower than that in the control group (CK), and the anthocyanin content in the high temperature and 24-Epibrassinolide group (HTE) was higher than that in the HT group and lower than CK group. Under HT treatment, the accumulation pattern of total sugar, reducing sugar and sucrose was similar to that of anthocyanins and lower than those of CK group at maturity stage. Compared with HT group, the contents of various sugars in HTE group were increased. The differences in transcriptome levels of 'Cabernet Sauvignon' fruits under the three treatments were analyzed. Through GO and KEGG enrichment, fourteen differential genes related to sucrose and starch metabolic pathways, among which 10 genes were significantly up-regulated and 4 genes were significantly down-regulated under HT and HTE treatments. The expressions of 11 genes are different in the phenylpropane metabolic pathway. Seven genes involved in anthocyanin synthesis were upregulated under the HT treatment, and 4 genes involved in lignin synthesis were significantly upregulated under the HT treatment, indicating that high temperature may promote lignin synthesis and reduce the accumulation of anthocyanins. In the endogenous hormone signaling pathway, the expression of the ABA signaling receptor genes PP2C and SnRK2 was significantly increased under high-temperature stress, and may be involved in regulating the synthesis of grape anthocyanin under high-temperature stress together with EBR. The expression patterns of some differential genes were verified by qRT-PCR, which confirmed the accuracy of transcriptome data. 【Conclusion】 EBR alleviated the inhibitory effect of high temperature stress on grapevine anthocyanin accumulation, probably due to the fact that EBR reduced the expression of lignin-related genes and changed the expression pattern of grape endogenous hormone signal transduction genes.

【Objective】 In view of the problem of odor non-point source pollution in fattening area of mutton sheep in recent years, the effects of bedding bed on growth performance of fattening lambs and odor components in the house were discussed, which provided a technical path for odor emission reduction in fattening sheep house.【Method】The purpose of the experiment was to investigate the effect of litter bed on growth performance in fattening lambs and odor components in lamb barn. Two-hundred fifty healthy fattening lambs with similar weight and age were used and randomly divided into 5 groups according to different bedding materials, which were control group (plain soil), group A (full-sawdust), and group B (furfural + sawdust), C group (rice husk + sawdust), and D group (corn cob + sawdust). The trial period was 90 days (d 1-45 in early period; d 46-90 in late period). The odor components in environment above and inside the litter bed were detected using GC-MS method during different periods, and the effect of litter bed on production performance in fattening lambs was also analyzed. 【Result】The results showed that: (1) Compared with the control group, the four groups with litter bed demonstrated an increase in daily feed intake (P < 0.05), increased by 7.7 % in group A and 8.7 % in Group B, 12.1 % in Group C, and 7.8 % in Group D. However, the daily gain and ratio of feed to gain exhibited no difference (P > 0.05). (2) Nine kinds and eight kinds of odor components were detected throughout test period above litter bed and inside litter bed, respectively, and the components consisted of 31 kinds of volatile organic compounds (VOCs) including 4 alcohols, 10 alkanes, 3 amines, 1 phenol, 7 esters, 4 ketones, 2 aldehydes, 3 acids, and 1 thiol. The odor kinds detected in 4 litter groups were basically same as the control group. (3) From content analysis of odor components, the alkane content was the highest with 52.0 %~77.5 % among all odor components, no matter experimental period or detected space; however, no difference was observed among all groups (P > 0.05). Also, the content of phenol or amine in litter groups demonstrated a decrease (P < 0.05) in two detected spaces in early and late periods, compared with the control, exhibiting the decrease in group C was obvious. Besides, the content of alcohol, amine, or phenol was higher (P < 0.05) in early period than that in late period both upper and inner spaces of litter bed; however, the ester content in late period was higher (P < 0.05) than that in early period. (4) During entire experimental period, four kinds of key odor-causing substances were detected both in upper and inner of litter bed, including 2-ethylhexanol, N,N-dimethylacetamide, phenol, and 1 H-indole-3-thiol. For the contents of the four odor-causing components, each litter group showed a decreasing trend, compared with the control group and the decrease in group C was the most obvious (P < 0.05). 【Conclusion】In summary, four combined litter beds in this study could improve growth performance in fattening lambs, and decrease odor content in environment. The results would provide a technical pathway for reduction of odor emission in sheep barn.

【Objective】The objective of this study was to clarify the effects of a controlled atmosphere (CA) with low O₂/high CO₂ on chlorophyll maintenance and quality of Yuluxiang pears during cold storage, to provide a theoretical basis and technical support for prolonging the storage life of Yuluxiang pears.【Methods】 Storage experiments were performed with commercial mature Yuluxiang pears treated with 1.0 μL·L^-11-MCP, 1% O₂, 3% CO₂, and 1.0 μL·L^-11-MCP combined with 1% O₂ and 3% CO₂ with air treatment as the control. The peel color, chlorophyll content, firmness, total soluble solids, titratable acid, ascorbic acid, and other quality indices were measured at 210 and 240 days of storage and 7 days of shelf life. Ethanol and acetaldehyde content, ethylene production, and respiratory rate of the fruits were detected by gas chromatography. The browning index of the fruit stalk and core was investigated and calculated.【Results】 Compared with ordinary cold storage, 1-MCP, CA, and CA + 1-MCP could better maintain the green color of Yuluxiang pear fruits and effectively reduce the degree of greasiness on the fruit surface. CA + 1-MCP had a more pronounced effect on the green color maintenance and greasiness control of the peel when refrigerated for 240 days and 240 + 7 days. 1-MCP and CA could inhibit the decline in fruit firmness, total soluble solids, and titratable acid. CA could inhibit browning of the core and stalk, but CA used alone reduced the content of ascorbic acid in the fruits, and CA + 1-MCP slowed the decline of ascorbic acid in CA fruits. The inhibitory effect of CA + 1-MCP on ethanol and acetaldehyde was more apparent when stored for 240 days, and the ethanol content of 20mg · L^-1 was below the tolerance threshold of Yuluxiang pears. CA + 1-MCP and 1-MCP had strong inhibitory effects on ethylene production across the entire storage period. At 240 days, CA + 1-MCP and CA had a stronger inhibitory effect on the respiratory rate than did 1-MCP.【Conclusion】 Yuluxiang pears are respiratory climacteric pears, resistant to low O₂ and high CO₂. The freshness maintenance effect of CA + 1-MCP on Yuluxiang pears was maintained after 210 days. Therefore, when the cold storage period is less than 210 days, a single 1-MCP treatment of 1.0 μ L · L^-1 could be used. When the cold storage period is greater than 210 days, fruits should be first treated with 1.0 μL·L^-1 1-MCP, and then stored under CA with low O₂/high CO₂ of 1% O₂ and 3% CO₂, which can maintain the appearance and internal quality of fruits, as well as significantly prolong the cold storage life.

【Objective】In order to optimize the production management of pasture and promote ecological and healthy breeding level of dairy cows, mastering the occurrence law of cow heat stress under the background of climate change could provide reference for optimizing the layout of animal husbandry, intelligent management and control of pasture, site selection and transformation, benefit improvement and so on. 【Method】Taking Jiangsu Province as an example, using the Era5 data set of global atmospheric reanalysis data from 1980 to 2020, the risk index (RI) was constructed based on the temperature humidity index (THI), which represents the degree of cow heat stress. The K-means clustering algorithm was selected to realize the risk zoning of heat stress of dairy cows, and the regional evaluation was carried out in combination with the characteristics of occurrence intensity, frequency, start and end time, as well as duration of heat stress. The climate tendency rate was calculated to analyze the change trend of the characteristics of cow heat stress in different risk areas. Based on the cumulative temperature humidity index (CTHI), Mann-Kendall test was used to determine the climate mutation points in different risk areas. Furthermore, the impacts of climate change on the occurrence characteristics of cow heat stress in different risk areas were analyzed from the daily and hourly time scales, respectively. 【Result】The study showed that the risk of heat stress of dairy cows in Jiangsu Province presented the distribution features of "high in the southwest and low in the northeast". The low-risk areas mainly included Huaibei and the middle-eastern area of Yangtze river and Huai river valley. The regional averaged value of THI was 73.63, and mild heat stress mainly occurred. The high-risk areas mainly include the areas along the southern Jiangsu and the west area of Yangtze river and Huai river valley. The regional averaged value of THI was 75.12, and the occurrence frequency of mild and moderate thermal stress was nearly the same. In the low-risk and high-risk areas, the start and end time of heat stress showed an advanced and delay trend, and the duration days showed an extended trend of 4.0 d/(10a) and 4.2 d/(10a) respectively, the values of THI all showed an increasing trend of 0.2/(10a),while the value of CTHI showed an increasing trend of 301.2/(10a) and 256.1/(10a) respectively. The frequencies of mild thermal stress were bimodal, mainly occurred from the early-June to the mid-July, and from the early-August to the middle-September, while the frequency of moderate thermal stress was unimodal, mainly occurred from mid-July to mid-August. The change of daily heat stress intensity basically presented a distribution of "sinusoidal", and the high incidence period was concentrated in 11:00-17:00. Affected by climate change, the heat stress of dairy cows in Jiangsu Province showed an obvious increasing trend, reaching a small peak in 2010. Then after a decline, it showed a steady strengthening trend, which exceeded the threshold of 0.05 significance level. In low and high risk areas, the highly impacted periods of cow heat stress were prolonged, the occurrence frequency increased, the coverage increased and the starting-time moved forward. The daily beginning time of the high incidence period of cow heat stress moved forward for about 1 hour, and the intensity of heat stress in high-risk areas was basically increased close to the medium level. 【Conclusion】Based on THI, RI and CTHI, the risk zoning assessment and climate impact analysis of cow heat stress could be realized, the high-risk areas, and key prevention and control periods of cow heat stress could be determined, and the climate change trend could be grasped. With the climate change, the heat stress of dairy cows in Jiangsu Province shows the characteristics of "earlier, stronger, longer and more", which should be actively dealt with.

【Objective】 The objective of this paper was to clearly demonstrate the effects of powdery mildew on photosynthetic characteristics of winter wheat and establish a model for simulating effects of powdery mildew stress on wheat photosynthetic productivity. 【Method】 To clarify the effects of powdery mildew on wheat photosynthetic characteristics, the powdery mildew experiments of wheat were conducted under two initial inoculation degrees of wheat powdery mildew at jointing and booting stages. On this basis, a prediction model of wheat powdery mildew severity was established to quantify the physiological effects of powdery mildew on wheat. And then, based on the single leaf net photosynthetic rate (Pn) and leaf area index (LAI), the wheat powdery mildew severity prediction model was coupled with the crop growth model (WheatGrow). 【Result】 Under the stress of powdery mildew, Pn and LAI showed a decreasing trend. Compared with the control (CK), the averaged Pn and LAI decreased by 18.81% and 23.41%, respectively. Moreover, the effects of stages of powdery mildew on Pn and LAI were more serious than the initial inoculation degrees. In general, the development of wheat powdery mildew in the field had obvious gentle period, exponential outbreak period and stable period, and the temporal dynamic characteristics of wheat powdery mildew epidemic under each treatment accorded with Logistic function. Therefore, based on the Logistic fitting results, the wheat powdery mildew disease stress factor was established to reflect the stress effects of powdery mildew on wheat physiological indexes. In addition, based on the photosynthesis productivity sub-model of WheatGrow and the effect factor of wheat powdery mildew severity, algorithms to simulate the effects of powdery mildew on Pn and LAI were established, and the improved WheatGrow model was estimated by using the powdery mildew experimental datasets in independent years. 【Conclusion】 The integrated model with powdery mildew stress algorithms was better than the original WheatGrow model in predicting Pn, LAI, aboveground biomass and yield under powdery mildew stress condition, with the simulation accuracy improved by 53.29%, 43.61%, 60.09% and 67.57%, respectively. The improved model can provide the digital tool and technical support for prediction of wheat powdery mildew severity and the quantitative evaluation of wheat yield loss.

【Objective】Root is an important organ for maize to obtain water and nutrients, and a developed root structure is the key to maximum maize yield potential, which is currently an important issue to be solved in maize cultivation research. Ethylene-Chlormequat-Potassium and nitrogen application can affect the development of the maize root system.  To clarify the effect of Ethylene-Chlormequat-Potassium on the construction of summer maize root morphology and yield under different nitrogen application rates can provide the theoretical and technical basis for the improvement of high yield and efficient cultivation management and rational fertilization of maize. 【Method】In 2019 and 2020, field experiments were carried out in Daliudian Village, Yanjiao Town, Langfang City and Shunyi Experimental Base, Chinese Academy of Agricultural Sciences, Shunyi District, Beijing respectively, using maize single cross Yudan 9953 as experimental material. A split-zone experimental design was used, with the Ethylene-Chlormequat-Potassium treatment (ECK) and the clear water control (CK) treatment as the main zones and the six nitrogen levels of 0 kg×hm^-2 (N0), 96 kg×hm^-2 (N96), 132 kg×hm^-2 (N132), 168 kg×hm^-2 (N168), 204 kg×hm^-2 (N204) and 240 kg×hm^-2 (N240) as the secondary zones, aiming to analyze the effects of ECK on root morphology and yield of summer maize at different nitrogen application rates. 【Result】The results showed that nitrogen application significantly increased root dry weight, number of aerial roots, root length, root surface area and root volume. Compared with no nitrogen application, root dry weight, the number of aerial roots, root length, root surface area and root volume increased by 18.0%, 49.5%, 20.8%, 26.2% and 34.6% on average with different nitrogen application rates, respectively. ECK treatment increased root dry weight, the number of root layers, number of roots in 1 to 2 layers and the number of aerial roots in summer maize with different nitrogen application rates by 10.4%–17.0%, 5.8%–12.6%, 10.8%–33.9% and 12.5%–79.6%, respectively, compared with CK; On the construction of root morphology, compared with CK, ECK treatment significantly increased the total root length, root surface area and root volume of summer maize with different nitrogen application rates by 7.5%–21.0%, 8.4%–29.3% and 14.3%–38.8%, respectively, and the root length with root diameter > 1.0 mm was significantly increased at medium and high nitrogen levels (N≥ N204). ECK treatment had no significant effect on summer maize yield per unit area in 2019 and 2020 with N0-N168, but significantly increased summer maize yield in 2019 and 2020 with N204 and N240, which increased by an average of 6.3% with N204 and 3.2% with N240 compared with CK. Correlation analysis showed that kernel number, 1000-kernel weight, root length, root surface area and root volume were positively correlated with summer maize yield, and the correlation coefficient between yield and root length was the highest.【Conclusion】ECK and nitrogen combined promoting maize root development and increasing summer maize yield under high nitrogen conditions. In the current study, spraying ECK at the V6 growth stage combined with 204 kg×hm^-2 N fertilizer was a suitable cultivation technique and N fertilizer management practices for high-yielding summer maize in the Beijing-Tianjin area.

【Objective】To explore the comprehensive response difference and physiological mechanism of different rice cultivars in response to elevated atmospheric CO₂ concentration and nitrogen nutrition. 【Method】In this study, a rice cultivar Liangyoupeijiu (LY) showed high response to CO₂ (high-response rice cultivar) and a rice cultivar Nanjing 9108 (NJ) showed low response to CO₂ (low-response rice cultivar) were selected as materials. Hydroponic experiments were carried out in the climate chamber. Two CO₂ treatments and two nitrogen treatments were set up with ambient CO₂ concentration (A-CO₂, 400 μmol mol^-1) and elevated CO₂ concentration (E-CO₂, 600 μmol mol^-1), and high nitrogen (HN, 1.25 mM NH₄NO₃) and low nitrogen (LN, 0.25 mM NH₄NO₃), respectively. The effects of elevated CO₂ concentration on root morphology and physiological activity, cytokinin (CTKs) content in leaves and roots, nitrogen assimilation enzyme activity, physiological characteristics of leaves, photosynthetic parameters, and dry matter accumulation of different rice cultivars were analyzed.【Result】(1) E-CO₂ significantly increased the total crown root number, total root length (except LN level), total root surface area and average diameter of LY, improved root respiration rate and maintained high root oxidation power, but had no significant or opposite effects on NJ. (2) Regardless of nitrogen level, E-CO₂ significantly increased CTKs content in LY leaves and roots, but significantly decreased zeatin nucleoside (ZR) content in NJ roots at HN level. (3) At LN level, E-CO₂ significantly increased GOGAT and GDH activities in LY leaves, but significantly decreased NR activities in NJ leaves. At HN level, the activity of LY nitrogen assimilation enzyme increased under E-CO₂ condition, but only NR activity increased in NJ. (4) At the LN level, E-CO₂ increased the net photosynthetic rate (Pn) of LY and NJ by 28.0% and 29.4%, respectively. At the HN level, that of the two varieties increased by 41.0% and 28.1%, respectively. The significant increase in photosynthetic response of LY was attributed to the significant increase in leaf maximum carboxylation efficiency (V_c,max), maximum photosynthetic electron transport efficiency (J_max), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) content, chlorophyll content, and leaf nitrogen content. (5) E-CO₂ significantly increased the leaf area per plant of LY under different nitrogen levels, but had no significant effect on NJ. (6) E-CO₂ significantly increased the organs and total biomass of LY, and the increased level under HN was significantly higher than that under LN level. E-CO₂ did not significantly affect the total biomass of NJ under different nitrogen treatments, but significantly reduced the underground biomass of NJ under HN (-16.7%). 【Conclusion】No matter at the HN or LN treatment, the response of dry matter production and physiological characteristics of LY to E-CO₂ was higher than that of NJ. In the early growth stage, LY had better root morphological characters and root activity, higher CTKs content, stronger nitrogen assimilation ability, larger green leaf area and photosynthetic response capacity, which were important reasons accounting for the higher response of dry matter production under E-CO₂ conditions.

【Objective】 In this research, an experimental animal infection model of canine influenza virus (CIV, H3N2 subtype) was established to better understand the pathogenesis of canine influenza and to lay the foundation for vaccine efficacy evaluation. 【Methods】 26 beagles aged 6-13 months with negative CIV Haemagglutination Inhibition (HI) antibody (HI < 1:10) were selected. Three were challenged by 1mL nasal spray of PBS. And twenty-three challenged by 1mL nasal spray of H3N2 CIV (A/canine/China/Huabei-170607/2017(H3N2), HB strain for short) with 5 groups (10、10³、10⁵、10⁶、10⁷ 50% EID₅₀) as 3, 5, 5, 5 and 5 beagles each group respectively_. Clinical symptoms, lung lesions, histopathological changes of lung, calculating the proportion of consolidation mass, HI antibody titer and virus shedding were examined 14 days after virus challenge together with three control beagles. 【Results】 3 beagles inoculated with a dose of 10 EID₅₀ H3N2 CIV did not show any clinical symptoms , gross lesions in lungs and histopathological changes. The consolidation rate was 0%. Virus shedding was not detected. The geometric mean titer (GMT) of HI antibodies was 1:15.9. However, 4/5 of beagles inoculated with a dose of 10³ EID₅₀ H3N2 CIV showed clinical symptoms and virus shedding such as puffing, runny nose and cough. 2/5 of beagles showed light lung consolidation, whose rate was 1.4%. The GMT of HI antibodies was 1:320. All beagles (5/5) infected with a dose of 10⁵ EID₅₀ H3N2 CIV showed clinical symptoms at day 5 after challenge such as runny nose and cough, virus shedding, lung consolidation and widened alveolar septum. The consolidation rate was 4.2%. The GMT of HI antibodies was 1:2940.7. 5/5 of beagles infected with a dose of 10⁶ EID₅₀ all showed severe clinical symptoms at day 4 after challenge such as cough and elevated body temperature, virus shedding, obvious pathological features in the lungs with GMT of HI antibodies were 1:2228.7. The clinical symptoms appeared earlier 1 day than that in 10⁵ EID₅₀ dose infection group. And the degree of lung consolidation increased. The lung consolidation ratio was 17.9%. 5/5 of beagles infected with doses of 10⁷ EID₅₀ all showed severe clinical symptoms at day 3 after challenge which appeared earlier 1 day than that in 10⁶ EID₅₀ dose infection group, virus shedding and widened alveolar septum in the lungs with GMT of HI antibodies were 1:2228.7. The consolidation rate of lung was 29.0%. Control beagles did not show any clinical symptoms, gross lesions and histopathological changes in lungs. And virus shedding was not detected. GMT of HI antibodies was ＜1:10. 【Conclusions】 The dose of 10⁶ EID⁵⁰ is the minimum virus inoculation dose that can cause obvious pathogenesis in beagles. An experimental animal infection model of CIV subtype H3N2 in beagles was established.

【Objective】The objective of this study was to investigate the effects of direct seeding cultivation on the growth period, lodging resistance, yield and economic benefits of different types of rice varieties, in order to provide a theoretical basis for the application and promotion of mechanized direct seeding rice.【Method】 For the early rice In 2020 and 2021, the conventional rice varieties Guiyu 9, Guiyu 11, Guiyefeng, Guangliangxiang 2 and hybrid rice Y Liangyou 1, which have a large area in Guangxi production, were used as test materials, in the field, Using the traditional manual transplanting as a control, the field is accurately direct seeding, For each treatment, there were three replicates. A split plot design was used in this experiment with planting method as the main plot, with rice varieties as the split plot, and set up three replications. The length of the growth period was observed, the morphology of main stem and the characteristics of the basal stem, as well as the lodging indicators such as breaking resistance, bending moment and lodging index was calculated, the yield and yield components were measured at the maturity stage, and the cost and economic benefits were calculated.【Result】(1) The growth period of direct seeding was shortened by about 2-6 days, which was mainly reflected in the period from sowing to the beginning of young spike. (2) the lodging resistance of direct seeding rice is relatively poor, and its plant height, center of gravity height and panicle dry weight are lower than that of transplanted rice; the stem thickness, wall thickness, fresh weight and dry weight of its N2 stem are also lower than that of transplanted rice, and the length of the stem is that the direct seeding rice is higher than that of transplanted rice, which may be the main reason for the weak lodging resistance of the direct rice. (3) Among the varieties tested, the actual yields of the remaining four rice varieties were lower than those of transplanted under direct-seeded cultivation, except for Yliangyou1. For varieties with relatively short growth period in the test materials, the yield under direct seeding conditions is significantly lower than that of transplanting, while for varieties with relatively long growth period，the yield difference between planting mothods is not significant, among the yield components, the increase in the number of grains per panicle and the seed setting rate are the main factors for increasing the yield of direct seeding rice. (4) From the analysis of economic benefits, among the varieties tested, Guiyu No. 11, which has a shorter growth period, has a significantly lower yield and economic benefit in direct seeding method, the economic benefits of direct seeding rice of the remaining four varieties were higher than those of transplanted rice. The main reason for this is that direct seeding rice saves labor costs in seedling and transplanting link.【Conclusion】At present, it is an urgent to develop a light and simple production model of rice with the main goal of preserving area and increasing efficiency. Compared with transplanted rice, direct seeding rice has obvious advantages such as shortening the growth period and reducing production costs. and there is a certain risk of lodging, the yield is easily affected by variety characteristics and environmental factors. Therefore, in the direct seeding cultivation of early rice, lodging-resistant varieties with medium maturity, reasonable stem length at the base, thick stems and thick stem walls can be selected. In cultivation management, the proportion of ear fertilizer should be appropriately increased to compensate for insufficient number of grains per panicle and seed setting rate can improve the yield of direct seeding rice.