Current issue

• 2020 Vol.36 No.30 Published:25 October 2020

  Inoculation with Arbuscular Mycorrhizal Fungi: Effects on Wheat-straw Decomposition and Upland Rice Growth Jia Yanyan, Zhu Jun, Gu Dalu, Yang Wenfei, Du Xiaofeng, Sun Aixia, Qian Xinmin, Wen Tinggang, Zhu Yunlin 2020, 36 (30):  1-6.  DOI: 10.11924/j.issn.1000-6850.casb20191000739 Abstract + ( 384 )   HTML ( 23 )   PDF ( 1299KB )   ( 152 ) To explore the effects of arbuscular mycorrhizal (AM) fungi on wheat straw decomposition and crop growth, upland rice and wheat straw were used as materials, a pot experiment was conducted to analyze the effects of AM fungi inoculation on the decomposition rate and nitrogen (N) release rate of wheat straw, the soil enzyme activities, the chlorophyll content, root activity and biomass of upland rice. Results showed that the colonization percentage of AM fungi was 27.17%-28.53%. Compared with the treatment of straw returning without AM fungi inoculation, the decomposition rate and nitrogen release rate of wheat straw were significantly improved under the treatment of straw returning with AM fungi inoculation; and the soil enzyme activities of cellulase, protease and urease all increased significantly under the treatment of straw returning with AM fungi inoculation. Straw returning with AM fungi inoculation treatment increased the root activity on the 60th day, the total chlorophyll content of leaves on the 90th day, and promoted the accumulation of aboveground part and root biomass significantly. Under the condition of wheat straw returning to the field, AM fungi can effectively promote the decomposition of wheat straw and the secretion of soil enzyme, increase the root activity of upland rice, which is conducive to the biomass accumulation of upland rice in dry paddy fields.

  Higher-nodal-position Tilling Traits of Rice Mutant Material W33: Study on the Utilization Value Huo Chuan, Wang Shiquan, Shen Junhong, Zeng Hongyan 2020, 36 (30):  7-12.  DOI: 10.11924/j.issn.1000-6850.casb20191100792 Abstract + ( 472 )   HTML ( 13 )   PDF ( 1209KB )   ( 117 ) The aim is to explore the utilization value of high tillering characteristics of rice mutant material W33 in rice breeding. Wild-type rice restorer line R818 and its mutant W33 with higher-nodal-position tillers were served as the test object, and potting experiment was used to study the difference of plants, tiller and panicle traits of R818 and W33, the difference of tiller, yield composition characters and grain yield of R818 and W33 were compared by field cultivation experiment, the character data of the test materials were measured. The results showed that there was no significant difference in plant height and average leaf length of main stem between W33 and R818 at the early stage of growth, and however there was significant or extremely significant difference in plant height and average leaf length of main stem between the two in the middle and late period; the average tiller number per plant of W33 was 7.5-8.8 times that of R818, the average effective panicle number of W33 was 8.6 times that of R818, and the average percentage of earring-tillers was equivalent to that of R818, but the length of single panicle, the number of branches per panicle and the number of grains per panicle were much lower than those of R818, while the 1000-grain weight slightly differed from that of R818. The grain yield per plant of W33 and R818 decreased with the density increased, it was the highest when the density was the lowest, and it was the lowest when the density was the highest. Although the yield per panicle of W33 was much lower than that of R818, there was no significant difference of population yield of W33 and R818 under the same density (Fvalue=3.7868<F0.05,1,4). Within a certain density range, the advantages of vigorous tillering ability and higher spikes rate of W33 could be fully demonstrated to make up for its disadvantage of low yield per panicle, and its population yield could finally reach the level equivalent to that of R818. It is suggested that the characteristics of stronger tillering ability and higher spikes rate of W33 should have certain utilization value in rice breeding.

  Screening of Wheat Landraces Germplasm for Wheat Quality Improvement Yang Lijuan, Wang Shikun, Sheng Kun, Fu Liang, Dong Yun, Jiang Zhikai 2020, 36 (30):  13-18.  DOI: 10.11924/j.issn.1000-6850.casb20190900686 Abstract + ( 329 )   HTML ( 6 )   PDF ( 1424KB )   ( 72 ) To select excellent wheat landraces germplasm that could be used to improve the quality of wheat, 212 wheat landraces were used as materials, Vp1B3 molecular marker and spraying in field were used to identify the resistance to spike germination. Hardness index method was used to measure hardness, and some agronomic characters were investigated. The results showed that among the 212 landraces, the genotypes of Vp-1Ba (susceptible to ear germination), Vp-1Bb (resistant to ear germination) and Vp-1Bc (resistant to ear germination) were 70.28%, 6.16% and 23.70%, respectively, and Vp-1Ba was the main genotype. There was no significant difference among the three genotypes. The spike germination rate of the 212 landraces ranged from 7.79% to 28.56%, with an average of 15.28%. The average hardness index (HI) was 71.22. The average plant height of the landraces reached 113.46 cm. The resistance to powdery mildew was rich in variation among the landraces and 3 landraces were immune to powdery mildew. The average grains per spike of landraces were 28.33 and the average 1000-grain weight was 30.96 g. A total of 12 landraces were selected including ‘Jinbaoyin’, ‘Yumai1’, ‘Dahongmang2’ and et al, they could be used for breeding targets of resistance to spike germination, hard grain, suitable plant height, resistance to powdery mildew and high yield. This study lays a foundation for further cultivation of high-quality wheat.

  Sowing Date and Yield of Maize: Effects on Photosynthetic Characteristics Gao Yonggang, Gao Ming, Zhao Huiying, Liu Dan, Yang Xiaoqiang, Zhang Zhiguo 2020, 36 (30):  19-27.  DOI: 10.11924/j.issn.1000-6850.casb20191000771 Abstract + ( 365 )   HTML ( 8 )   PDF ( 1315KB )   ( 166 ) The paper aims to understand the effects of sowing date on the photosynthetic characteristics and yield of maize and to guide the high-yield cultivation of maize. The sowing date test by stages was carried out with the medium ripening maize ‘Keyu15’, and the related data were analyzed with mathematical statistics methods. The results showed that, photosynthetic characteristics of maize leaves from different sowing dates were significantly different, the net photosynthetic rate (Pn), transpiration rate (Tr), chlorophyll content and water use efficiency (WUE) were increased first and then declined along with the sowing date delaying. While the concentration of CO2 (Ci) had an opposite change, and stomatal conductivity (Gs) had no obvious change law. Pn had extremely significant positive correlation with Tr, WUE, Ta, PAR, and had extremely significant negative correlation with Ci. It was illustrated that the main meteorological factors affecting net photosynthetic rate of maize leaves were the air temperature, photosynthetic active radiation and soil moisture. The growth status and yield of maize were affected by the interaction and synergy between photosynthetic parameters of maize leaves. Suitable sowing date can make full use of climate resources, such as solar radiation, air temperature and water, and can improve photosynthetic efficiency and matter accumulation and transformation, and increase production significantly.

  Water Stress: Effects on Non-structural Carbohydrates Contents in Different Peanut Organs Yang Weiqiang, Shi Chengren, Kang Tao, Ding Hong, Xu Yang, Dai Liangxiang, Zhang Zhimeng 2020, 36 (30):  28-35.  DOI: 10.11924/j.issn.1000-6850.casb20191000748 Abstract + ( 482 )   HTML ( 13 )   PDF ( 1308KB )   ( 77 ) The aim is to explore the dynamic changes of “sink source flow” of non-structural carbohydrate (NSC) in different organs of peanut at different growth stages under water stress. Two peanut varieties ‘HY 20’ and ‘HY 27’ were used as materials. Pool planting in rainfall shelter was conducted under controlled conditions. The dynamic changes of non-structure carbohydrate (NSC) in leaf, stem, root and pod of peanut were analyzed at different growth stages under water stress. The results showed that the contents of soluble sugar and starch in leaf, stem and root were increased, while the contents in pod were significantly decreased under drought stress during the whole growth period. The peak value of soluble sugar content in leaves appeared about 15d earlier under drought stress at any growth stage. The “source” substances were exported in advance, while the output decreased, which made the leaves senescent in advance. The contents of NSC in pod were increased under drought stress at the early growth stage, whereas drought stress after the pod-setting stage was beneficial to the transformation of NSC in pod. The content of NSC in leaves was relatively low and the change was small under normal growth condition. In general, the transport and transformation of NSC from source to sink are reduced under drought stress, and the “sink” capacity of pods is reduced.

  Technical Model of In-situ Fertilizer Utilization of Agricultural Wastes in Hunan Province Peng Zhihong, Chu Fei, Li Gou, Yang Wei 2020, 36 (30):  36-39.  DOI: 10.11924/j.issn.1000-6850.casb2020-0089 Abstract + ( 325 )   HTML ( 11 )   PDF ( 1031KB )   ( 78 ) In view of the agricultural wastes’ types and quantity in Hunan Province, five utilization modes were designed according to different agricultural waste resources and the characteristics of organic fertilizer products, including (1) chicken manure + crop residue organic fertilizer applied to fruits, vegetables and tea fields; (2) cow dung + tobacco waste organic fertilizer applied to food crops and economic crops; (3) mushroom residue organic fertilizer; (4) vegetable waste + cake organic fertilizer applied to vegetables; (5) chicken manure + returned material organic fertilizer applied to economic crops. The results show that there are obvious advantages by using agricultural wastes above described, such as reducing the cost of waste consumption and enterprise production, avoiding secondary pollution, and obtaining more organic fertilizer resources. These technical models could be copied and popularized, which provide management references on different types of wastes for different regions and enterprises, and solve the technical problem of in-situ treatment of agricultural pollutants. The models could have positive significance for environmental protection and sustainable development of agriculture.

  Film Mulching During Different Periods: Effects on Carbon Fixation and Carbon Balance of Maize Field in Aealian Semi-arid Region Zhang Zhe, Si Pengfei, Zhang Xu, Feng Liangshan, Dong Wenyi, Liu Enke, Feng Chen, Zhang Yanqing, Sun Zhanxiang 2020, 36 (30):  40-48.  DOI: 10.11924/j.issn.1000-6850.casb20191000714 Abstract + ( 384 )   HTML ( 12 )   PDF ( 1338KB )   ( 92 ) The paper aims to determine the mulching effect of carbon fixation and emission reduction in aealian semi-arid region and to provide a theoretical basis for constructing a low-carbon mulching pattern by comparing the effects of cultivating maize under 3 patterns of autumn mulching (AM), spring mulching (SM) and no mulching (NM) on the differences of short-term soil organic carbon storage and carbon balance. The results showed that: AM significantly increased the grain yield, aboveground biomass of maize and the root biomass of maize in 0-60 cm soil depth (P<0.05); in the 0-100 cm soil layer, the soil organic carbon storage of NM, SM, AM and initial was 89.2, 84.2, 83.7 and 90.53 Mg/hm2, respectively, and there was no significant difference at the same soil layer (P>0.05); the average of soil respiration CO2-C release of NM, SM and AM was 2.10, 2.09, 2.37 Mg/(hm2·a), respectively, and their carbon balance was -522, -498, -474 kg CO2-C/(hm2·a), respectively. In conclusion, AM increases the carbon input of the system as well as the carbon emission of soil respiration, however, it will not cause the decline of soil organic carbon pool in the short term, and can reduce the carbon emission per unit area yield to a greater extent. So, AM is a climate-friendly low-carbon agricultural technology.

  Effect of Green Manure Chinese Milk Vetch on Nitrogen Balance in Paddy Soil System: A Review Wang Ying, Luo Qi, Lv Xinxin, Tang Shan, Zhou Nannan 2020, 36 (30):  49-54.  DOI: 10.11924/j.issn.1000-6850.casb20191000747 Abstract + ( 387 )   HTML ( 9 )   PDF ( 1109KB )   ( 84 ) To systematically clarify the change of nitrogen circulation in paddy field after introducing Chinese milk vetch (Astragalus sinicus L.) as leguminous catch crop, this paper synthetically reviewed the effects of Chinese milk vetch on nitrogen (N) input and output in paddy soil and evaluated the N balance in rice-Chinese milk vetch cropping system. The conclusions mainly included: (1) Chinese milk vetch could effectively fix N and replace partial fertilizer, increase the N use efficiency; (2) by increasing rice yield and N content, Chinese milk vetch could raise N output through rice harvest; (3) Chinese milk vetch could effectively reduce N runoff loss; (4) Chinese milk vetch may have the potential to reduce nitrogen leaching loss, but the supporting data was limited; (5) Chinese milk vetch could significantly reduce NH3 volatilization in paddy fields, but the effect on N2O emission remained controversial at present. In summary, on the basis of maintaining rice yield, Chinese milk vetch could effectively reduce the environmental risk caused by N loss and ameliorate the N balance in paddy soil system.

  Continuous Cropping of Crayfish and Rice: Effects on Functional Diversity of Soil Microorganisms Fan Limin, Yang Guang, Dong Yuanyuan, Dong Xinxu, Qiu Liping, Song Chao, Chen Jiazhang 2020, 36 (30):  55-61.  DOI: 10.11924/j.issn.1000-6850.casb20191000711 Abstract + ( 331 )   HTML ( 8 )   PDF ( 1259KB )   ( 63 ) To investigate the effects of continuous cropping of crayfish and rice on functional diversity of soil microorganisms, some rice paddy fields and ponds with continuous cropping of crayfish and rice were selected as research objects, Biolog-ECO method was used to detect the utilizing capacity of 31 carbon sources by microorganism in soils. The metabolic activity and the difference of metabolic diversity of microorganism were studied in the rice paddy fields with continuous cropping of crayfish and rice and rice paddy field. The influencing factors were analyzed. The results showed that the contents of nitrogen, phosphorus, potassium and organic matter, and the microbial metabolic activities in fields with continuous cropping of crayfish and rice were all lower than that in rice paddy fields (P<0.05). The metabolic diversities of soil microorganisms in fields with continuous cropping of crayfish and rice and rice paddy fields were significantly different (P<0.05, and the results of redundancy analysis showed that and the difference was positively correlated with the content of organic matter in soil (R2=0.814, P =0.001). To sum up, the continuous cropping of crayfish and rice can influence the functional diversity of soil microorganisms significantly, and the reduction of fertilizer uses, especially the reductions of organic matter, is the important cause.

  Characteristics and Influencing Factors of Cadmium Accumulation in Rice: Gleyed Paddy Soil and Hydrogric Paddy Soil Zheng Shun’an, Liu Daili, Zhang Mingkui, Zhang Shuang 2020, 36 (30):  62-67.  DOI: 10.11924/j.issn.1000-6850.casb20191000722 Abstract + ( 466 )   HTML ( 11 )   PDF ( 1088KB )   ( 74 ) Cadmium pollution in farmland soil and rice grain is serious in China. To understand the relationship between accumulation of cadmium in paddy soil and in rice organs can provide a basis for safe production of rice. Taking the gleyed and hydrogric paddy soil as the research objects, the characteristics and influencing factors of cadmium accumulation in rice growth in both types of paddy soil were studied by collecting soil and rice samples in pairs. The results showed that under similar soil cadmium pollution, the cadmium accumulation in the organs of rice grown in the gleyed paddy soil was significantly lower than that in the hydrogric paddy soil. The average contents of cadmium in the stems-leaves and brown rice of the rice plant grown in the gleyed paddy soil were only 55.53% and 56.10% of that in the hydrogric paddy soil, indicating that the amount of Cd uptake by rice plant from the gleyed paddy soil was significantly lower than that from the hydrogric paddy soil. The total soil cadmium content was the main factor that affected the accumulation of cadmium in organs of rice plants grown in both soils. However, the effects of other factors on cadmium accumulation in rice organs were quite different between the two types of farmland soils. The factors that affected the accumulation of cadmium in the gleyed paddy soil were exchangeable ferrous and clay content, while the CEC in the hydrogric paddy soil was an important factor. The results also showed that the available cadmium in the gleyed paddy soil determined by fresh soil samples was more effective than that determined by air-dried soil for predicting cadmium accumulation in rice organs. It is concluded that soil gleization could reduce the uptake of cadmium by rice and the risk of cadmium contamination in brown rice.

  Autotetraploid Non-heading Chinese Cabbage Suzhouqing: Induction and Identification Pan Jingwen, Wang Hongyao, Li Lin, Zhang Shuning, Li Ying, Hou Xilin, Liu Tongkun 2020, 36 (30):  68-74.  DOI: 10.11924/j.issn.1000-6850.casb20191100788 Abstract + ( 540 )   HTML ( 6 )   PDF ( 1808KB )   ( 86 ) To obtain the high-yield and high-quality non-heading Chinese cabbage autotetraploid Suzhouqing, in this study, cotyledon growth points of diploid Suzhouqing seedling plants were treated using colchicines solution with concentration of 0.1%, 0.2%, and 0.3%, respectively. After five treatments, tetraploid Suzhouqing plants were screened and identified by morphological and cytological methods. The agronomic characters and quality difference were compared between diploid and tetraploid Suzhouqing. The results showed that the doubling effect of Suzhouqing was the best when the concentration of colchicine was 0.2%. According to morphological anatomy, the tetraploid plant type, leaf, flower, seed pod and seed size all had an obvious trend of increasing. Tetraploid plant leaves had larger stomata size and smaller stomatal density than diploids. And the pollen grain of tetraploid plants was larger and more irregular than that of diploids. Cytologic results showed that there were 40 chromosomes in tetraploid plants and 20 chromosomes in diploid plants. Flow cytometry analysis indicated that tetraploid plants had about twice the fluorescence intensity of diploid. The results showed that the contents of physiological indexes of tetraploid Suzhouqing were different from those of diploid through quality comparison and analysis. Through the comparison of agronomic characters, the average individual mass, leaf width and leaf thickness all increased to a certain extent. In this study, colchicine was used to inhibit the formation of spindles at mitotic anaphase and to achieve chromosome doubling. A new germplasm of non-heading Chinese cabbage was created to provide a theoretical basis and germplasm resources for breeding new tetraploid non- heading Chinese cabbage.

  Ubiquitin Modification and Its Research Progress in Plant Proteomics Zhang Jialin, Li Haiying 2020, 36 (30):  75-81.  DOI: 10.11924/j.issn.1000-6850.casb2020-002 Abstract + ( 764 )   HTML ( 31 )   PDF ( 1391KB )   ( 132 ) Ubiquitination modification is an important post-translational modification of proteins, which participates in the regulation of many important life activities in cells. In recent years, with the development of ubiquitinated proteins enrichment technology and mass spectrometry technology, great progress has been made in ubiquitination proteomics. At present, there are many ubiquitination proteomics studies in animals and yeasts, but few in plants. In order to summarize the latest research results of ubiquitination proteomics in plants, the ubiquitination modifications, the identification of ubiquitination sites by mass spectrometry, the enrichment methods of ubiquitination proteins and the application of ubiquitination proteomics in plant light regulation, hormone treatment and stress conditions were reviewed in this paper, which could provide the rationale for the latest research of ubiquitination modifications in plants.

  Transport Protein CAXs and HMAs Related to Cadmium Absorbing and Transferring of Plant: A Review Liu Mei, Li Zuran, Zu Yanqun 2020, 36 (30):  82-90.  DOI: 10.11924/j.issn.1000-6850.casb20191100806 Abstract + ( 515 )   HTML ( 11 )   PDF ( 1317KB )   ( 78 ) To explore the molecular mechanism of cadmium tolerance of plant and provide a theoretical basis for plant protein transporting heavy metals, this article summarizes the structure and function of transport protein CAXs (cation/H+ exchangers) and HMAs (Heavy metal ATPase), and their effects on plant growth, as well as the detoxification mechanism of heavy metals under synergy. CAXs play an important role in improving phytoremediation potential and strengthening plant nutrition, which is mainly related to plants transport divalent cations into the membrane, also determine the concentration of Ca2+ in plants, and participate in transportation and detoxicification of heavy metal ions. The operation of CAXs is related to the electrochemical H+ gradient generated by plasma membrane and vacuolar membrane of HMAs across the plasma membrane of the cell, which provides essential energy support for CAXs transportation. However, the synergistic mechanism of CAXs and HMAs needs further research. It is suggested that the study of CAXs and HMAs activities and the interrelationship between CAXs and HMAs could provide a basis for future plant genetic engineering for remediation heavy metal pollution soil.

  Effects of Different Promoters, WPRE and ITRs on Recombinant Baculovirus Expression of Newcastle Disease F Protein Cao Dechen, Ye Lei, Li Weiqing, Li Sainan, Gao Dongni, Ge Jingping 2020, 36 (30):  91-97.  DOI: 10.11924/j.issn.1000-6850.casb2020-0011 Abstract + ( 366 )   HTML ( 7 )   PDF ( 1921KB )   ( 58 ) The aims are to improve the expression ability of genetically engineered vaccines to the Newcastle disease virus F protein, and lay a foundation for developing highly efficient and genetically engineered vaccines. The expression differences of baculovirus with different promoters and expression elements to F protein in Chinese hamster ovary cell were detected by Western blot. The results of Western blot showed that the expression level of complex promoter containing CMV enhancer region and chicken actin promoter region (CBA promoter) was higher than that of Cytomegaoviyns promoter (CMV) by 24.52%-231.18%, and the expression level of wood-chuck hepatitis virus post-transcriptional regulatory element (WPRE) was increased by 2.9-8.6 times, but adeno-associated virus inverted terminal repeats (ITRs) only increased the expression level of 1.95%-9.27%. In conclusion, the adjustment ability of CBA promoter is much higher than that of CMV promoter, while group WPRE could get a positive result, but group ITRs does not change significantly.

  A Strain of Bacillus subtilis Producing High-Yield L-lysine: Construction Xia Shuli, Han Jing, Wang Lixue, Yang Chunlei, Liu Changyue, Wang Hailiang, Wu Kuang, Shi Huiling 2020, 36 (30):  98-105.  DOI: 10.11924/j.issn.1000-6850.casb20191000699 Abstract + ( 417 )   HTML ( 5 )   PDF ( 1865KB )   ( 66 ) To breed a strain producing L-lysine with non-resistance, high yield, good genetic stability, low production cost, pepper anther and Bacillus subtilis were used as test materials, the shuttle expression vector pHT43 and gene knockout vector pK18mobsacB was performed as a vector to transform lysine-rich protein gene (CFLR) into Bacillus subtilis. After two rounds of self-recombination and screening of culture medium, the final strain CMCC (B) 63501/pK18mobsacB-ΔALA::CFLR, with high yield of L-lysine was obtained without antibiotic resistance. After 20 generations of serial passage, the strain still expressed a significant higher number of CFLR copies than the wild type. The subsequent data of High-Performance Liquid Chromatography (HPLC) revealed that the content of L-lysine in recombinant strain was 64.89% higher than that of the wild strain. The above results indicated that the recombinant strain we constructed were featured with non-resistance, high yield, good genetic stability and low purification cost. Therefore, the strain exhibits outstanding potential for future applications.

  Nitrogen Metabolic Characteristics of Two Cultivable Bacteria Liu Zhixin, Yao Na, Liu Lingzhi 2020, 36 (30):  106-111.  DOI: 10.11924/j.issn.1000-6850.casb20191100789 Abstract + ( 305 )   HTML ( 7 )   PDF ( 1395KB )   ( 42 ) To study the N metabolic characteristics of culturable bacteria in soil, and discuss the possible mechanism of microorganisms in soil N transformation, 2 strains, named SY5-4 and SY11-10 isolated from apple orchard soil were selected to analyze the growth characteristics, and their capabilities of nitrogen transformation, by using the traditional culture method combined with molecular technology. The results showed that, in heterotrophic condition, the generation time of SY5-4 and SY11-10 was 243.5 min and 202.7 min, respectively. The concentration of NH4+-N in the medium maintained at a high level, while the concentration of NH4+-N, NO2--N and NO3--N increased first and decreased afterwards, in the process of bacterial growth. The nitrification (amoA and hao), and denitrification (nosZ, norB, nirK and nap) gene detection showed that, strain SY11-10 had a variety of N transformation potential. In conclusion, the nitrogen in medium changed in the process of bacterial growth, and different nitrogen transformation genes were detected in the tested strains, which indicated that the isolated strains participated in various N metabolism pathways.

  The Stem and Root Rot of Sweet Potato: Dispersal and Infection Path and Field Epidemic Factors Yao Haifeng, Qiu Zhiling, Shen Xiaoling, Lou Binggan, Gu Jianqiang, Zhu Xiaoxiang 2020, 36 (30):  112-119.  DOI: 10.11924/j.issn.1000-6850.casb20191000723 Abstract + ( 562 )   HTML ( 9 )   PDF ( 1675KB )   ( 57 ) To understand the occurrence, epidemic regularity and impact factors of stem rot disease (SRD) of sweet potato in the main producing areas, such as Lin’an of Zhejiang Province, laboratory study, field experiments and investigation were carried out from 2016 to 2019 by using different varieties of sweet potato. Results showed that high susceptibility of major varieties was one of the main inducing factors for the SRD’s epidemic in recent years. The source of primary infection was the pathogen which overwintered in disease debris and tubers. Symptom did not appear until the quantity of pathogen in soil reached 104-105 cfu/cm3. High temperature and high humidity accelerated the development of SRD. The transportation of infected seed tubers and seedlings was the major way of long distance transmission and spread. SRD could be effectively decreased though pathogen-free seedlings, rotation, cultivation technique of deep furrow and high ridge.

  Psoralea corylifolia L. Extract: Effect on Biological Activity of Rice Sheath Blight Wei Chang, Xu Qingyun, Li Yuejuan, Wang Jing, Guan Lijie 2020, 36 (30):  120-126.  DOI: 10.11924/j.issn.1000-6850.casb20191100835 Abstract + ( 358 )   HTML ( 9 )   PDF ( 3173KB )   ( 65 ) The purpose is to investigate the activity of Psoralea corylifolia L. extract on rice sheath blight. We studied the inhibition effects of Psoralea corylifolia L. extract against rice sheath blight by the hypha growth inhibition test, asclerotia germination inhibition test, SEM technologies and potted plant test, and verified the results by field trials. The results showed that EC50 value of the inhibition effect of Psoralea corylifolia L. extract on mycelium growth of rice sheath blight was 30.8159 mg/L, the inhibition rate to sclerotium germination was 43.33% at 810 mg/L. SEM observation showed that hypha arrangement and morphology changed significantly after being treated by Psoralea corylifolia L. extract for 5 days. The results of potted plant test showed that the preventive and control effect of 150 times diluted 0.2% microemulsion against rice sheath blight was 94% and 78.46%, respectively; the field trials showed that the control effect of 0.2% microemulsion was 72.22% at 90 g/hm2 after dosing once at intillering stage, booting stage and full heading stage, respectively. Psoralea corylifolia L. extract can inhibit mycelial growth and sclerotic germination of rice sheath blight, destroy its morphological structure, its microemulsion has remarkable control efficiency on rice sheath blight.

  Spraying NATIVO 75% Water Dispersal Granules: Regulation of Nitrogen Absorption and Growth of Rice Lv Liang, Chang Xiangqian, Yang Xiaolin, Yuan Bin, Zhou Chunhua, Zhang Shu 2020, 36 (30):  127-134.  DOI: 10.11924/j.issn.1000-6850.casb20191100803 Abstract + ( 531 )   HTML ( 8 )   PDF ( 1314KB )   ( 52 ) The aim is to explore the mechanism and effect on rice growth, nitrogen absorption and utilization efficiency by spraying NATIVO 75% water dispersal granules. In this study, field plot experiments were carried out, fertilization conditions such as total N, semi-N, and non-N were designed, and the effects of spraying NATIVO in different periods on rice nitrogen absorption, utilization, and rice yield were analyzed. The results showed that the chlorophyll SPAD value was significantly increased when spraying NATIVO twice at the end of rice boosting stage and rice full-heading stage under the condition of nitrogen application. At the end of rice boosting and full-heading stage, spraying NATIVO on rice leaf surface twice could significantly increase the leaf area index, the weight of thousands of grains, and the solid seed rate of rice compared with the check. The results also showed that spraying NATIVO on the rice leaf surface could obviously promote the absorption of nitrogen in rice, improve the utilization efficiency of nitrogen, and obtain higher rice yield. In conclusion, spraying NATIVO on the leaf surface at rice boosting and full heading stage can promote the growth of rice, improve the nitrogen utilization efficiency, and obtain higher rice yield.

  Intercropping and Mixed Cropping of Wheat Varieties: Effects on Wheat Aphid Occurrence Li Hongyan, Liu Qian, Li Ye, Song Weihu, Liu Changzhong 2020, 36 (30):  135-142.  DOI: 10.11924/j.issn.1000-6850.casb20191100799 Abstract + ( 367 )   HTML ( 8 )   PDF ( 1293KB )   ( 49 ) This study is aimed at controlling the occurrence number of wheat aphid with species diversity by intercropping and mixed cropping of different wheat varieties. The intercropping and mixed cropping was conducted with five wheat varieties. The wheat variety with monoculture was used as the control. The number of wheat aphids was investigated at the critical stage and the aphid-peak stage. The insect resistance among different wheat varieties was compared with aphid ratio method. The occurrence of wheat aphids was used to compare the differences among different combinations, and to contrast the control effects. The results showed that the susceptibility of monocropping varieties was highly susceptible: Shi 7816 > 95-108 > Lantian13, susceptible: Lantian 6 > Lantian 1. The occurrence of wheat aphid in the intercropping and mixed cropping combinations was significantly lower than that of one monoculture variety (P<0.05), at the flowering and grouting period. Except Lantian 1/Shi 7816, Lantian 13/95-108, Lantian 6/95-108 and Lantian 1/95-108 having negative-increasing control effect, all the intercropping and mixed cropping combinations showed control effect on the wheat aphid. The average control effect of intercropping was 12.94% with a range of -24.67%-44.33%. The average control effect of mixed cropping was 28.92%, with a range of 1.67%-61.33%. Relatively, the best combinations of control effect were Lantian 1/Lantian 6/Lantian 13/95-108/shi7816, with the control effect of 44.33% and 61.33%, respectively. In conclusion, most of the intercropping and mixed cropping combinations have effective control effect on the occurrence of wheat aphid.

  Different Adjuvants: Effects on S Protein Immunogenicity of Porcine Transmissible Gastroenteritis Virus and Porcine Epidemic Diarrhea Virus Han Taotao, Li Lu, Tang Qinghai, Wu Guangyan, Sun Guoyin, Li Xiaonan, Chang Qiuling, Yang Hai, Tang Siping, Wang Fangyu 2020, 36 (30):  143-140.  DOI: 10.11924/j.issn.1000-6850.casb20191000740 Abstract + ( 459 )   HTML ( 6 )   PDF ( 2055KB )   ( 71 ) This study aims to explore the effects of different adjuvants on the immunogenicity of Transmissible gastroenteritis virus (TGEV) S protein and Porcine epidemic diarrhea virus (PEDV) S protein. IPTG-induced recombinant expression strains Rosetta (DE3)-pET28a-TGEV-S2/3 and BL21 (DE3) -pET28a-PEDV-S1/2/3 were used to prepare recombinant proteins TGEV-S2, TGEV-S3, PEDV-S1, PEDV-S2 and PEDV-S3, and to conduct SDS-PAGE and western blot identification. The recombinant protein was mixed with three types of adjuvants, ISA 71VG, ISA 201VG and ISA 15AVG respectively, to prepare immunogen which was used to vaccinate layers. Western blot was used to detect serum antibody titer of layers, and immunoperoxidase monolayer cell staining assay (IPMA) was used to detect antibody and pathogen reactivity. The average daily weight gain of the flock was monitored. The results showed that the molecular weights of recombinant proteins TGEV-S2, TGEV-S3, PEDV-S1, PEDV-S2 and PEDV-S3 were 25 ku, 28 ku, 26 ku, 24 ku and 21 ku, respectively. Western blot analysis showed that all the five proteins had good immunogenicity. The highest antibody titer was 64000 times, 32000 times and 8000 times respectively in the ISA 201VG adjuvant group, ISA 71VG adjuvant group and ISA 15AVG adjuvant group, while no specific antibody was detected in the control group. The ISA 71VG and ISA 201VG group had a relatively large decrease in the egg production rate, while the ISA15AVG adjuvant group had a relatively small impact on the egg production rate, and the egg production rate in the experimental group returned to normal 7 days after immunization. The average daily weight gain of layers in the ISA 71VG adjuvant group was significantly decreased; while the average daily weight gain of layers in the ISA 201VG and ISA 15AVG adjuvant group was not significantly different from that in the control group. The serum antibody of ISA 201VG group had good reactivity with neutralization titer up to 1:256. The immune effect of the vaccine with ISA 201VG adjuvant was better than that of the other two adjuvants.

  Recombinase-Polymerase Mediated Isothermal Amplification Technology: Application in Identification of Animal-Derived Ingredients Wang Yiqin, Yang Fan, Guo Wenli, Chen Shaobo, Bao Yonggan, Jing Wenkui, Zhang Zhifeng, Chang Hong, Kang Xiaoping 2020, 36 (30):  151-157.  DOI: 10.11924/j.issn.1000-6850.casb20191000777 Abstract + ( 426 )   HTML ( 8 )   PDF ( 1452KB )   ( 49 ) The identification technology of animal-derived ingredients requires high specificity, sensitivity and repeatability of detection methods in combating adulteration and smuggling of meat products, maintaining market orders and protecting wildlife resources. In this study, the detection and identification technologies of animal-derived ingredients were described, which had the characteristics of diversity and limitation. The principle and application of recombinase-polymerase mediated isothermal amplification technology were summarized, the limitations of PCR technology on instruments were solved, and the early isothermal amplification technology was optimized. The study points out that the recombinase-polymerase mediated isothermal amplification technology could be a technical basis for the rapid and accurate identification of animal-derived ingredients, and has a good application prospect in the diagnosis of animal epidemics.

  The Application of Machine Learning in Crop Variety Recognition: A Review Yang Lingyan, Zhang Hongyan, Chen Yufeng, Liu Yawen 2020, 36 (30):  158-164.  DOI: 10.11924/j.issn.1000-6850.casb20191100813 Abstract + ( 782 )   HTML ( 13 )   PDF ( 1732KB )   ( 110 ) The successful application of machine learning in the field of image recognition provides a new idea for the automatic recognition of crop varieties. In order to fully understand the application status of machine learning in crop variety recognition and grasp the development trend and research direction of crop variety recognition, this paper summarized the common acquisition methods of crop image, and analyzed the research status of crop varieties recognition based on spectral image and RGB image with machine learning methods. The research on crop variety recognition based on RGB images started earlier, the cost of image acquisition is relatively low, and the recognition rate is general; the research on crop variety recognition based on hyperspectral images has developed rapidly in recent years, and the recognition accuracy is relatively high, but the cost of image acquisition is higher and easily affected by environmental factors. Through the summary, the existing problems in crop variety recognition research are pointed out, and it is considered that deep learning has a wide application prospect in the automatic recognition of crop varieties.