Current issue

• 2023 Vol.39 No.6 Published:25 February 2023

  Original article

  Direct Seeding Rice: Research Progress and Development Strategy WU Longmei, ZHANG Yue, LIU Yan, ZOU Jixiang, YANG Taotao, BAO Xiaozhe, HUANG Qing, CHEN Qingchun, JIANG Yaozhi, LIANG Qiaoli, ZHANG Bin 2023, 39 (6):  1-5.  DOI: 10.11924/j.issn.1000-6850.casb2022-0154 Abstract + ( 195 )   HTML ( 8 )   PDF ( 1008KB )   ( 57 ) Direct seeding is an important rice planting method. It is widely used at home and abroad due to its advantages of saving labor, time and cost and significantly improving the comprehensive benefits of rice planting. In this paper, the research status and progress of direct seeding rice at home and abroad were elaborated, and three main direct seeding rice planting methods, namely wet direct seeding, water direct seeding and dry direct seeding, were introduced. Main problems in direct seeding rice production were analyzed from the aspects of yield, weed control and lodging resistance, and countermeasures were proposed as cultivating suitable varieties, appropriate nitrogen application, lodging resistance, weed control, and integrated development of agronomic practices and agricultural machinery. The paper also discussed the development trend of direct seeding rice, in order to provide reference for the cultivation and promotion of direct seeding rice with high yield and lodging resistance.

  Effects of Sowing Date on Growth and Yield of Spring Maize in East Gansu ZHANG Kexin, YU Xiao, ZHANG Moucao 2023, 39 (6):  6-12.  DOI: 10.11924/j.issn.1000-6850.casb2022-0210 Abstract + ( 187 )   HTML ( 7 )   PDF ( 1124KB )   ( 60 ) To explore the most suitable sowing period for the growth and development and yield formation of spring maize in east Gansu (Longdong), and to provide reference for local maize planting, based on the maize regional joint test of the National Agricultural Meteorological Experiment Station - the Xifeng spring maize sowing by stage test, which was carried out from 2018 to 2020, we studied the effects of different sowing dates on the growth and development process and yield formation of Longdong spring maize. The results showed that for every 10 days’ delay of sowing, the duration of the whole growth period of maize was shortened by 5.5 days. The influence of sowing date on the duration of the whole spring maize growth period mainly concentrated on the emergence time and the seedling growth stage. With the delay of the sowing date, the time required for emergence and seedling growth were shortened. The duration of the whole growth period of maize was significantly and negatively correlated with temperature, while significantly and positively correlated with the accumulated temperature and sunshine hours. Precipitation had little effect on the duration of the whole growth period of maize. With the delay of the sowing date, the number of kernels per plant, 100-kernel weight and yield of maize showed a trend of first increase and then decrease, that is, the above agronomic traits under sowing date SD2 and SD3 were higher than those under SD1 and SD4. Appropriate late sowing, abundant precipitation before tasseling, and high temperature and accumulated temperature after tasseling were beneficial to the increase of 100-kernel weight and the number of kernels per plant, thus increasing the yield. The suitable sowing period of spring maize in Longdong is from late April to early May, when the meteorological condition is most conducive to the growth and development of spring maize and can maximize the maize yield.

  Intercropping of Different Maize Genotypes: Comprehensive Evaluation by DTOPSIS Method YANG Haifeng, HONG Defeng, MA Junfeng, WANG Qun, WEI Xiaoyi 2023, 39 (6):  13-17.  DOI: 10.11924/j.issn.1000-6850.casb2022-0144 Abstract + ( 145 )   HTML ( 2 )   PDF ( 1149KB )   ( 26 ) In order to study the effect of intercropping of different maize genotypes, six maize varieties of different genotypes were used as experimental materials to set 3 combinations and 9 treatments. The monoculture and intercropping effect were analyzed comprehensively and compared by using DTOPSIS method (dynamic technique for order preference by similarity to ideal solution) based on entropy weight. Through exploring new methods of comparative analysis, a new dominant pattern of maize intercropping with different genotypes was obtained. The results showed that the Ci value of treatment 4 was the highest (C4=0.9829), and that of treatment 5 was the lowest (C5=0.0330). The Ci value of the other two combinations of intercropping were all greater than the Ci value of monoculture. The intercropping pattern of ‘DH605’ with ‘WK702’, and ‘DH618’ with ‘DH371’ had the effect of increasing yield and efficiency, which could be applied in production.

  Effect of Paclobutrazol and Micro Sprinkler Irrigation on the Quality and Dwarfing of Millet Cultivated on Wheat Stubble JING Hua, MA Aiping, KANG Xiuli, WANG Yuzhi, CUI Huanhu, HUANG Xuefang 2023, 39 (6):  18-25.  DOI: 10.11924/j.issn.1000-6850.casb2022-0045 Abstract + ( 176 )   HTML ( 4 )   PDF ( 1215KB )   ( 19 ) In order to effectively improve the quality and lodging resistance of millet cultivated on wheat stubble, the effects of different spraying concentrations of paclobutrazol (PP333) at different leaf ages and sprinkler irrigation quantities at different growth stages on the quality and dwarfing of millet cultivated on wheat stubble were studied by the methods of split plot and random block in 2017-2019 in Linfen of Shanxi Province. The results showed that the effects of the treatments on protein and its three kinds of amino acids, fat, starch and fiber quality of millet cultivated on wheat stubble were significantly different (P<0.01). The protein content and the average content of 8 essential amino acids, 4 semi-essential amino acids and 3 non essential amino acids were significantly increased by spraying PP333 at the concentration of 1.2% at the 8-leaf stage. By spraying PP333 at the concentration of 0.8%-1.2%, except tryptophan acid, the contents of protein and other 14 amino acids were better than that by spraying clear water (CK). Spraying PP333 at the concentration of 1% and 0.8% at 4-leaf stage was beneficial to improving the content of fat and starch. With the increase of micro sprinkler irrigation quantity, the content of protein and the average content of 8 essential amino acids, 4 semi-essential amino acids and 3 non essential amino acids basically showed a downward trend. With treatment of micro sprinkler irrigation 0.0 mm (jointing stage 0.0 mm+booting stage 0.0 mm), except cysteine and tryptophan acids, the average content of protein and 3 kinds of amino acids, and the content of 13 amino acids and fat were the highest, and there was significant difference (P<0.01) with the other 3 treatments of sprinkler irrigation quantities (jointing stage 37.5 mm, booting stage 37.5 mm, jointing stage 37.5 mm+booting stage 37.5 mm). Spraying PP333 at the concentration of 1.0%-1.2% at 6-leaf stage and decreasing micro sprinkler irrigation quantity in the critical growth stage could have better dwarfing effects. This study can provide theoretical and technical support for improving the quality and lodging resistance of millet cultivated on wheat stubble.

  The Response of Sea-island Cotton Strains to the Spraying Time and Frequency of Defoliants BAI Yulin, WANG Chengqiang, DU Bin, LIU Lu, LIU Xia 2023, 39 (6):  26-34.  DOI: 10.11924/j.issn.1000-6850.casb2022-0272 Abstract + ( 138 )   HTML ( 3 )   PDF ( 1441KB )   ( 19 ) In order to clarify the effects of spraying time and frequency of defoliants on leaf abscission, boll opening, yield traits and fiber quality of different sea-island cotton strains, ZX102 and ZX113 were used as test materials and 3 spraying times and 2 spraying frequencies were set. Three-factor completely randomized experiments were used to analyze the responses of different sea-island cotton strains to different treatments. The result showed that the use of defoliants significantly improved the defoliation rate, and the defoliation rate of the two strains at 40% and 50% boll opening rate reached 90% about 15 days after using defoliants, and they were significantly higher than that of the water control (P<0.05). The use of defoliants at 40% and 50% boll opening rate reduced the macron value, fibre length and fibre strength of the two strains, which were manifested as CK>T2>T1; at 40% boll opening rate, the macron value under T1 treatment was significantly lower than that under CK (P<0.05). The boll weight and seed value of the two strains under different treatments were CK>T2>T1, and the boll weight at 40% boll opening rate under T1 treatment was significantly lower than that under CK (P<0.05). In order to ensure the yield and fiber quality, T2 spraying can be used at 50% boll opening rate for mechanical harvesting of sea-island cotton.

  Upland Cotton Germplasms: Genetic Diversity Analysis of Main Yield and Fiber Quality Traits JIA Xiaoyun, ZHAO Hongxia, ZHU Jijie, WANG Guoyin, LI Miao, WANG Shijie 2023, 39 (6):  35-40.  DOI: 10.11924/j.issn.1000-6850.casb2022-0308 Abstract + ( 127 )   HTML ( 2 )   PDF ( 1079KB )   ( 24 ) In order to improve the utilization efficiency of cotton germplasm resources and increase the genetic diversity of backbone parents, genetic diversity analysis, correlation analysis, principal component analysis and cluster analysis were conducted on 114 germplasm materials. The coefficient of variation (CV) of lint percentage, single boll weight and micronaire were relatively large, and the CV of fiber uniformity was the smallest. The genetic diversity index of seed index was the largest, and that of fiber elongation rate was the smallest. The cumulative contribution rate of the first three factors of principal component analysis reached 83.91%. Single boll weight was significantly positively correlated with lint percentage and seed index, lint percentage was significantly negatively correlated with seed index, and fiber quality traits were positively correlated with each other. Seed index was mainly negatively correlated with fiber quality, and single boll weight and lint percentage were significantly positively correlated with fiber quality. The tested materials were divided into 3 groups by cluster analysis. Group I was mainly colored cotton varieties. Group II was materials with excellent fiber quality and common yield characters. Group III showed better comprehensive performance of yield and fiber quality. This study defined typical characteristics of different upland cotton material types, and provided certain reference for the efficient utilization of germplasm materials and the combination of parents.

  Analysis of CRISPR Technology Research Trend in China from 2000 to 2021 Based on Bibliometrics YANG Haifeng, LI Menghe, WANG Yali, DONG Yanqi, GU Guobing, WANG Ze, SUN Yuzhuo, SHEN Siyang, ZHANG Xu 2023, 39 (6):  41-51.  DOI: 10.11924/j.issn.1000-6850.casb2022-0521 Abstract + ( 146 )   HTML ( 4 )   PDF ( 2571KB )   ( 23 ) In order to understand the research status in the field of CRISPR technology, taking 8031 documents screened from the Chinese Database of China National Knowledge Network (CNKI) as the data source, and using visualization software CiteSpace 5.8 R3 and Excel 2019, we analyzed the annual volume of CRISPR technical research literature, issuing institutions, funds, journals, keywords, etc. In CNKI Chinese database, the annual number of documents about CRISPR technology showed an upward trend from 2014 to 2021 and reached the peak in 2019. Comprehensive universities and colleges, agricultural universities and colleges and academies of agricultural sciences were the main institutions of CRISPR technology research. The authors with the largest number of published papers were Duan Guangcai of Zhengzhou University and Bi Yanzhen of the Institute of Animal Husbandry and Veterinary Medicine of Hubei Academy of Agricultural Sciences, both of them published 19 papers during 2000-2021. The number of papers supported by NSFC (National Natural Science Foundation of China) projects was the largest (2107), accounting for 26.24%. High frequency keywords showed that CRISPR technology was most widely used in rice in agricultural field. Keyword centrality indicated that gene editing, gene knockout and rice were the research hotspots in the field of CRISPR technology in China. Keyword emergence analysis showed that editing efficiency, salt stress, reactive oxygen species, potato, growth and development and overexpression might be the research hotspots in this field in the future. This paper understands and grasps CRISPR technology from a macro perspective, which provides theoretical support for the research of agricultural biological breeding technology in China.

  Effects of Chemical Fertilizer Reduction on Growth Characteristics and Fertilizer Use Efficiency of Tomato ZHENG Jianchao, DONG Fei 2023, 39 (6):  52-57.  DOI: 10.11924/j.issn.1000-6850.casb2022-0233 Abstract + ( 172 )   HTML ( 2 )   PDF ( 1149KB )   ( 45 ) To study the effects of chemical fertilizer reduction combined with bio-fertilizer and fulvic acid on tomato growth and fertilizer use efficiency under the condition of facility cultivation, tomato variety ‘Yuanyi 504’ was used as the experimental material. The experiment adopted randomized block design. Five treatments were set as: conventional fertilization (CK), base fertilizer reduction by 40%, top dressing soluble fertilizer reduction by 20%, top dressing soluble fertilizer reduction by 40%, and no fertilizer application (blank). The results showed that the plant height of tomato decreased with the fertilizer application reduction. There was no significant difference among CK, base fertilizer reduction by 40% treatment and topdressing soluble fertilizer reduction by 20% treatment. The base fertilizer reduction by 40% treatment had little effect on tomato stem diameter. There was no significant difference in the number of leaf nodes and panicles among CK, base fertilizer reduction by 40% treatment and topdressing soluble fertilizer reduction by 20% treatment. The fertilizer use efficiency of tomato was improved by reducing fertilizer application. The fertilizer use efficiency of base fertilizer reduction by 40% treatment was the highest, which was not significantly different from that of topdressing soluble fertilizer reduction by 20% treatment. The partial productivity of base fertilizer reduction by 40% treatment was higher than that of CK, top dressing soluble fertilizer reduction by 20% treatment and topdressing soluble fertilizer reduction by 40% treatment by 17.1%, 9.4% and 16.4%, respectively. The yield of CK was the highest, but was not significantly different from that of base fertilizer reduction by 40% treatment and topdressing soluble fertilizer reduction by 20% treatment. To sum up, under the condition of appropriate application of bio-fertilizer and fulvic acid, base fertilizer reduction by 40% or topdressing soluble fertilizer reduction by 20% had little effect on the growth and yield of facility tomato.

  Effects of N, P and K Application Time on Yield, Quality and Nutrient Uptake of Processing Tomato Under Chemical Fertilizer Reduction LI Yali, BAI Jing, WU Zhenghu, HALIHASH Yibati, LI Qingjun 2023, 39 (6):  58-63.  DOI: 10.11924/j.issn.1000-6850.casb2022-0157 Abstract + ( 148 )   HTML ( 5 )   PDF ( 1207KB )   ( 44 ) To provide technical support for reducing application and increasing efficiency of chemical fertilizers in processing tomato cultivation, the authors studied the effects of different application time of nitrogen (N), phosphorus (P) and potassium (K) fertilizer on the growth and nutritional status of processing tomato under the condition of reducing nitrogen and phosphorus fertilizer by 20%. A field experiment was employed with five treatments: (1) control treatment (CK), P and K were applied as basal fertilizer and N was applied in the whole growth season; (2) T1, N and P were reduced by 20%, P and K were basal applied with N was applied in the whole growth; (3) T2, N and P were reduced by 20%, N and P were applied before anthesis, while N and K were applied after anthesis; (4) T3, N and P were reduced by 20%, N and K were applied before anthesis, while N and P were applied after anthesis; (5) T4, N and P were reduced by 20%, and N, P and K were applied throughout the whole growth season. The results showed that: there was no significant difference of the quality of processed tomato among different treatments. Compared with those of CK, there was no significant difference of biomass, yield and NPK absorption of tomato of T2 and T4, but T2 was better than T4. Compared with those of CK, the yield of T1 and T3 decreased by 11 and 19 t/hm2; the biomass of T1 and T3 significantly decreased by 1.6 and 2.13 t/hm2; the N uptake significantly decreased by 49.43 and 60.0 kg/hm2; the P uptake significantly decreased by 8.47 and 12.37 kg/hm2; and the K uptake significantly decreased by 40.93 and 50.01 kg/hm2, respectively. All reached significant difference level. The effects of T1 on the growth and nutrient uptake of processing tomato were slightly better than those of T3. In summary, under the condition of reducing 20% of N and P fertilizer, applying N and P before anthesis and N and K after anthesis can play the best role in improving the quality, yield and economic benefits of processing tomato.

  Effects of Jiabowen Soil Conditioner on Radish Yield and Quality and Soil Physical and Chemical Properties YIN Liping, LIU Siyuan, CAI Chengmei, SHI Xiaoli, ZHU Xiaojuan, YUAN Guoming, WANG Jidong, ZHANG Hui, XU Cong, MA Hongbo 2023, 39 (6):  64-71.  DOI: 10.11924/j.issn.1000-6850.casb222-0197 Abstract + ( 157 )   HTML ( 3 )   PDF ( 1268KB )   ( 29 ) To improve the quality of soil and radish, appropriate soil conditioner and its application amount were studied, and the effects of Jiabowen soil conditioner on the yield and quality of radish and soil physical and chemical properties were explored by taking no soil conditioner as the control. The results showed that the application of Jiabowen soil conditioner could increase the yield, single root weight and good fruit rate of radish, and reduce the incidence rate of radish nematodes. The sugar content, alkalinity and color of radish pulp were improved by the conditioner. The soil organic matter, pH, alkali-hydrolyzed nitrogen, available phosphorus and available potassium were increased. The number of soil bacteria, fungi and actinomycetes were increased too. The bulk density of soil was reduced, and the formation of water stable aggregates was improved. Therefore, the application of Jiabowen soil conditioner can increase radish yield, improve radish quality and soil structure, and enhance soil fertility and microbial diversity. The best application amount of Jiabowen soil conditioner is 4800 kg/hm2.

  Application Effect of Ethephon, Medium Trace Element and Functional Fertilizer on Ginger ZHOU Jie, QI Chuandong, TANG Chun, GUO Fengling, QIN Zhushan, CAI Xiaodong, WU Jinping 2023, 39 (6):  72-76.  DOI: 10.11924/j.issn.1000-6850.casb2022-0206 Abstract + ( 184 )   HTML ( 3 )   PDF ( 1044KB )   ( 44 ) The effects of ethephon seed soaking, and field application of medium trace element and functional fertilizer on the yield and quality of ginger were studied, aiming to provide a feasible scheme for the high-yield and high-efficiency cultivation of ginger. The results showed that seed soaking with ethephon and increasing application of medium trace element and functional fertilizer could increase plant height, leaf number of main stem and stem diameter of the aboveground part, which were beneficial to the increase of yield. In terms of ginger quality, ethephon and fertilizer treatment had no significant effect on the content of ascorbic acid, but the content of crude fiber decreased. The optimum concentration of ethephon for seed soaking was 350 mg/kg. The amount of functional fertilizer applied to ginger was 525 kg/hm2. The effect of boron fertilizer on yield was slightly better than that of zinc fertilizer, and the effect of the two on the quality of ginger was slightly different. The application of 1500 kg/hm2 silicon fertilizer could not only keep the quality of ginger, but also achieve the best effect of yield increase.

  Resource Utilization of Agricultural and Forestry Wastes: Research Progress WEI Jiqian, LI Dan, WANG Jingwen, HUANG Yue, MO Jianchu 2023, 39 (6):  77-81.  DOI: 10.11924/j.issn.1000-6850.casb2022-0234 Abstract + ( 335 )   HTML ( 17 )   PDF ( 1048KB )   ( 83 ) Agricultural and forestry waste is a valuable biomass resource. If the resource cannot be used efficiently, it will cause serious environmental pollution and even great harm to human health. Therefore, the resource utilization of agricultural and forestry wastes is the important content of controlling agricultural non-point source pollution, saving biomass resources, energy conservation and emission reduction, protecting the ecological environment, achieving the goal of peaking carbon emissions and carbon neutralization, and social and economic sustainable development. In order to promote the resource utilization of agricultural and forestry wastes, this paper summarized the progress achieved in this field at home and abroad in recent years.

  Research Progress of Superabsorbent Polymers Applicable to Agriculture and Forestry LIU Yana, E Shengzhe, WANG Lanying, MA Xiaofeng, YUAN Jinhua, ZHANG Peng, LU Gangbin, YE Gengkang, ZHAO Tianxin, WANG Yuxuan 2023, 39 (6):  82-89.  DOI: 10.11924/j.issn.1000-6850.casb2022-0225 Abstract + ( 159 )   HTML ( 4 )   PDF ( 1212KB )   ( 35 ) Water-retaining agent, also known as superabsorbent polymer, has the ability of absorbing water and controlling the release of fertilizer, and can promote the growth of plants. Water-retaining agents can be synthesized from synthetic polymers, natural polymers, and combinations of organic and inorganic materials. The synthesis of water-retaining agent includes physical, chemical and hybrid bonding, which is mainly realized by bulk polymerization, solution polymerization, inverse suspension polymerization, radiation polymerization and other methods. Based on this, the basic concept, properties, mechanism of action, synthesis methods and classification of water-retaining agents are reviewed, and some existing problems are also discussed in this paper. It is pointed out that the future research focus of water-retaining agent should be on high salt resistance, reusable property and mass production potential.

  Effects of Biochar Addition on Cd Enrichment in Lettuce TENG Bingqin, MA Qianqian, WU Jun, DUAN Xuejiao, BI Dongmei, CAI Liqun 2023, 39 (6):  90-96.  DOI: 10.11924/j.issn.1000-6850.casb2022-0413 Abstract + ( 153 )   HTML ( 2 )   PDF ( 1258KB )   ( 27 ) To investigate the effect of biochar addition on the absorption and accumulation of Cd in lettuce under Cd stress, lettuce was used as the experimental material. By pot experiment, 0%, 1%, 2%, and 3% of biochar were added to the soil with exogenous Cd content of 3 mg/kg, respectively. After the lettuce was harvested, the data of soil pH, soil organic carbon, lettuce yield, Cd enrichment and translocation in lettuce, and the occurrence form of Cd in soil were measured. The results showed that the addition of biochar could significantly increase the content of soil organic carbon (P≤0.05). When the biochar addition amount was 3%, the soil organic carbon increased by 35.14%-40.87% compared with that of the CK group. The addition of biochar significantly reduced the Cd content of lettuce. Especially the addition of 3% of biochar, which could reduce the Cd content of lettuce leaves from 0.79 mg/kg to 0.44 mg/kg. Biochar can significantly reduce the enrichment factor and translocation factor of Cd in lettuce, increase the content of residual Cd, and significantly reduce the content of acid-extractable, reducible and oxidizable Cd. Therefore, the addition of biochar has a significant inhibitory effect on soil Cd contamination and Cd accumulation in lettuce, and 3% of biochar addition has the best effect.

  Effects of Soil Factors on Atrazine Adsorption Kinetics and Microbial Remediation of Contaminated Soil PAN Hongyang, ZHANG Kai, FAN Xiaoxu 2023, 39 (6):  97-104.  DOI: 10.11924/j.issn.1000-6850.casb2022-0218 Abstract + ( 140 )   HTML ( 2 )   PDF ( 1192KB )   ( 24 ) The herbicide atrazine has caused high pollution risk to farmland soil in north China, and the effective in-situ remediation of atrazine pollution has become a research hotspot. Due to the advantages of high efficiency, low cost and being environment-friendly, microbial remediation technology has received widespread attention to remediate atrazine contaminated soil in-situ. In this paper, the effects of soil factors on the kinetics of atrazine adsorption-desorption, as well as the proliferation and vitality of functional microorganisms were summarized from the aspects of soil texture, pH, physical structure, nutrient level and so on. Meanwhile, some feasible suggestions and schemes were proposed to enhance the results of in-situ microbial remediation in the future. In conclusion, this paper can lay a foundation for the selection of bioremediation measures for contaminated soil according to local conditions, and provide theoretical guidance for strengthening microbial remediation of contaminated soil in-situ.

  Bacillus amyloliquefaciens P-r21: Broad-spectrum Antibacterial Effect and Control of Tomato Gray Mold LI Yongli, YUAN Chunyan, ZHOU Zhou, WANG Chunsheng, LEI Zhenshan 2023, 39 (6):  105-110.  DOI: 10.11924/j.issn.1000-6850.casb2022-0170 Abstract + ( 133 )   HTML ( 1 )   PDF ( 1626KB )   ( 27 ) This experiment aims at clarifying the broad-spectrum antibacterial effect of endophytic Bacillus amyloliquefaciens strain P-r21, and determining its control effect on tomato gray mold. In this study, the fermentation conditions of strain P-r21 were optimized. The antibacterial activity of strain P-r21 against six pathogens and its inhibition on spore germination of Botrytis cinerea were determined by plate confrontation method, and its control effect on tomato gray mold was studied by in vitro inoculation test. The results showed that: the optimum fermentation media was PYJ, and the optimum condition was initial pH 6.0 and fermentation time of 12 h. Strain P-r21 exhibited antagonistic ability to six plant pathogens (Botrytis cinerea, Fusarium proliferatum, Rhizoctonia cerealis, Gaeumannomyces graminis, Fusarium graminearum, and Colletotrichum karstii). The inhibition effects of the strain on the growth of C. karstii and B. cinerea were the strongest, and the inhibition rates were 88.0% and 84.5%, respectively. The inhibition rate of B. cinerea spore germination treated with fermentation filtrate was 80.6%. The control effects on tomato gray mold disease of leaves and fruits treated with fermentation filtrate were 100% and 80.0%, respectively. The control effect of fermentation filtrate diluted 10 times could reach 67.1% and 60.7%, respectively. This study clarifies that strain P-r21 has broad-spectrum antibacterial effect and can be used for the control of tomato gray mold. The study lays a foundation for the application of this strain in the biological control of plant diseases.

  Bacillus velezensis: Toxicity and Field Efficacy Against Cucumber Powdery Mildew and Its Safety Evaluation XIA Lijuan, XU Zhonghuai, DONG Xuejuan, WAN Li 2023, 39 (6):  111-115.  DOI: 10.11924/j.issn.1000-6850.casb2022-0208 Abstract + ( 146 )   HTML ( 4 )   PDF ( 1171KB )   ( 29 ) The study aims to explore the control effect of microbial fungicide Bacillus velezensis on cucumber powdery mildew in field. Five cucumber varieties were used in the experiment including ‘Zhongnong 26’, ‘Jinpei 98’, ‘Changchunmici’, ‘Jinyu 168’ and ‘Xuebaihuanggua’. The toxicity of Bacillus velezensis against Sphaerotheca fuliginea of ‘Zhongnong 26’ was determined by pot method in the laboratory, the control efficacy on ‘Jinyu 168’ and ‘Xuebaihuanggua’ were investigated in Shangdong and Sichuan, and the safety evaluation on ‘Zhongnong 26’, ‘Jinpei 98’ and ‘Changchunmici’ were conducted by pot method. Under indoor condition, the EC50 value of Bacillus velezensis on ‘Zhongnong 26’ was 26.7 million CFU/mL, and the activity was relative high. The control efficacy of Bacillus velezensis in Shangdong and Sichuan was 62.08%-75.58% 14 d after two times of application, which was significantly better than that of control pesticides. The growth inhibition rate of ‘Zhongnong 26’, ‘Jinpei 98’ and ‘Changchunmici’ had no significant difference when the varieties were sprayed 20 billion CFU/g Bacillus velezensis SG at the dosage of 3000, 6000 and 12000 g a.i./hm2, indicating the safety of the fungicide. Bacillus velezensis has good indoor activity and control efficacy against cucumber powdery mildew, and it is safe for cucumber and can be promoted for application.

  Blister Blight Lesions of Tea (Camellia sinensis L. Kuntze) Leaves: Microbial Diversity Analysis and Identification of the Disease Fungi CHEN Yiyong, ZHOU Bo, LI Jianlong, TANG Hao, CUI Yingying, WU Wenhao, LIU Jiayu, TANG Jinchi 2023, 39 (6):  116-123.  DOI: 10.11924/j.issn.1000-6850.casb2022-0348 Abstract + ( 150 )   HTML ( 2 )   PDF ( 1725KB )   ( 30 ) The aims are to analyze the microbial diversity on the surface of tea blister blight diseased leaves, and isolate and identify fungal microorganisms on diseased tea leaves. Tea leaves infected with blister blight disease and healthy leaves were used as test materials, and the leaf surface was observed by scanning electron microscopy, and the bacterial and fungal community compositions of different leaves were analyzed by 16S and ITS sequencing. 113 kinds of bacteria and 252 kinds of fungi were detected on the surface of tea blister blight diseased leaves, and 237 kinds of bacteria and 161 kinds of fungi were detected on healthy leaves. The bacterial diversity of diseased leaves was significantly lower than that of healthy leaves, and the fungi diversity of diseased leaves was higher than that of healthy leaves. Compared with healthy leaves, the abundance of Cladosporium and Pestalotiopsis in diseased leaves was lower, while that of Mortierella was higher. Fungal microorganism Cladosporium cladosporioides was isolated by PDA medium and identified, which might play an important role in the infection of blister blight disease. The microbial community structure on the surface of tea leaves changed significantly after tea blister blight disease infection, and the isolated and identified Cladosporium cladosporium might be closely related to the pathogenic process of tea blister blight disease.

  Screening, Identification and Functional Determination of Endophytic Bacteria from Forage Grass at Alpine Grassland in Qinghai Province YAO Hemin, TANG Mei, GONG Xuehua, JIN Mengjun, YANG Chengde 2023, 39 (6):  124-128.  DOI: 10.11924/j.issn.1000-6850.casb2022-0185 Abstract + ( 143 )   HTML ( 2 )   PDF ( 1368KB )   ( 22 ) The antagonistic strains against Fusarium oxysporum f.sp.cucumerium were screened from endophytic bacteria of forage grass at alpine grassland in Qinghai Province, and then were identified by morphological characteristics and homology analysis of 16Sr DNA gene sequence, and their biological functions were determined. The results showed that 36 strains of the 81 tested endophytic bacteria strains had antagonistic effects, accounting for 44.0%, and the inhibition rate of 13 strains isolated from the root were all above 50.0%, among which the inhibition rate of 2018GH11 was above 50.0% against 6 genera 8 species of pathogenic fungi, and 67.6% against Fusarium oxysporum. 2018GH11 had a broad spectrum of inhibition, and it was identified as Bacillus siamese by the morphological characteristics and homology analysis of 16Sr DNA gene sequence. 2018GH11 had nitrogen fixation ability, but the ability to produce IAA and solubilize phosphate was not obvious. In pot experiment, when the amount of 2018GH11 was 0.50%, the cucumber height, stem diameter, leaf number, fresh weight and dry weight were increased by 15.33%, 39.40%, 22.22%, 215.99% and 126.70%, respectively, compared with those of the control plants. In summary, the endophytic bacteria 2018GH11 from alpine grassland has a good effect on controlling disease and promoting plant growth, and a great potential for development.

  Secondary Metabolites Extracted From Sixteen Plant Species: Antibacterial Effects on Two Strains of Plant Pathogenic Bacteria WANG Xin, SHEN Yalun, CHEN Sibo, LI Yunpeng, LIU Jianan 2023, 39 (6):  129-134.  DOI: 10.11924/j.issn.1000-6850.casb2022-0195 Abstract + ( 146 )   HTML ( 3 )   PDF ( 1757KB )   ( 30 ) The study aims to search and develop environment-friendly and effective Chinese herbal medicine resources to inhibit plant pathogenic fungi, and to provide a research basis for the development of plant-derived fungicides. In this study, the fungicidal activity of 16 ethanol extracts from Ligusticum chuanxiong Hort. ex S.H. Qiu & al., Phellodendron amurense Rupr., Forsythia suspense (Thunb.)Vahl, and Euphorbia humifusa Willd. ex Schltdl. were determined, and the effects of petroleum ether extract of Ligusticum chuanxiong Hort. ex S.H. Qiu & al., which had the best effect on mycelial growth inhibition, on the spore germination and mycelial morphology of Fusarium oxysporum f. sp. Cucumerinum. and Alternaria solani (Ell.et Mart.) Jones et Grout. fungus were observed. The results showed that the petroleum ether extract of Ligusticum chuanxiong Hort. ex S.H. Qiu & al., ethyl acetate extract of Forsythia suspense (Thunb.) Vahl and n-butanol extract of Phellodendron amurense Rupr. had good inhibitory activities on the mycelial growth of the two pathogens. Among them, the intermediate inhibitory concentration (IC50) of Ligusticum chuanxiong Hort. ex S.H. Qiu & al. petroleum ether extract on the mycelial growth of Fusarium oxysporum f. sp. Cucumerinum. and Alternaria solani (Ell.et Mart.) Jones et Grout. was 3.68 mg/mL and 5.82 mg/mL, respectively; Ligusticum chuanxiong Hort. ex S.H. Qiu & al. petroleum ether extract also inhibited the spore germination of Fusarium oxysporum f. sp. Cucumerinum with an IC50 of 11.29 mg/mL, and caused abnormal mycelial morphology at the IC50 concentration of mycelial growth. The petroleum ether extract of Ligusticum chuanxiong Hort. ex S.H. Qiu & al. can be used as a new source of plant-derived inhibition agent for further study.

  Metarhizium rileyi SL Strain Liquid Fermentation Conditions: Optimization by Response Surface Methodology XUE Rui, SHEN Shaoyun, DENG Xizhou, CHEN Cong, PENG Yuejin, DU Guangzu, CHEN Bin 2023, 39 (6):  135-143.  DOI: 10.11924/j.issn.1000-6850.casb2022-0343 Abstract + ( 168 )   HTML ( 4 )   PDF ( 2364KB )   ( 27 ) Metarhizium rileyi is a widely distributed entomopathogenic fungi with high pathogenicity to noctuid pests. The present study aims to optimize the liquid fermentation conditions of Metarhizium rileyi, and further increase fermentation broth biomass. In this experiment, the single factor experiment was selected for evaluating the effect of three culture solutions on fermentation broth biomass of Metarhizium rileyi, and screened the main factors affecting bioyield by Plackett-Burman. The suitable range of key factors was determined by the steepest climbing test. The multiple regression equation of mycelial biomass in liquid fermentation of Metarhizium rileyi SL200714 was established by Response Surface Method. The results showed that the strain of Metarhizium rileyi SL200714 was subjected to liquid fermentation using SDY medium under the conditions of culture temperature of 25.08℃, rotating speed of 182.11 r/min, and liquid volume of 100.03/250 mL. In this optimal culture solution, 0.361 g mycelial biomass could be produced per 10 mL fermentation broth. Response surface methodology was used to optimize the liquid fermentation culture conditions of Metarhizium rileyi, and to improve the biological yield per milliliter of Metarhizium rileyi fermentation broth, and the study could lay a foundation for the subsequent industrial production of Metarhizium rileyi conidial powder.

  The Elemental Composition in Water and Sediment of Culture Habitat of Eriocheir sinensis in the Yangcheng Lake XUE Junren, LIU Hongbo, JIANG Tao, CHEN Xiubao, CHEN Yun, YANG Jian 2023, 39 (6):  144-151.  DOI: 10.11924/j.issn.1000-6850.casb2022-0184 Abstract + ( 191 )   HTML ( 2 )   PDF ( 1401KB )   ( 30 ) In order to understand the characteristics of elements’ contents in habitat water and sediment of the Chinese mitten crab (Eriocheir sinensis) in the Yangcheng Lake, and explore the correlations between the elements and the Chinese mitten crab, the water and sediment samples were collected monthly from the purse seine culture area of Chinese mitten crabs in the Yangcheng Lake during the year-long period. The concentrations of the elements in water were determined by inductively coupled plasma mass spectrometer (ICP-MS), and the concentrations of the elements in sediment were determined by ICP-MS, inductively coupled plasma atomic emission spectrometry (ICP-AES) and X-ray fluorescence analysis (XRF), respectively. The results showed that the elements’ contents of the water samples could meet Pollution-free Food-Quality of Water for Freshwater Aquiculture and Environmental Quality Standards for Surface Water (Class I). The elements’ contents of the sediment samples were not within the risk screening value range of Soil Environmental Quality Risk Control Standard for Soil Contamination of Agricultural Land. Pearson correlation analysis of the 10 elements (e.g., Na) used for the identification of the origin of Chinese mitten crab indicated that there was a very significantly positive correlation for Ba (P<0.01), and significantly positive correlation (P<0.05) for Mg and Zn between crab and water samples. In contrast, K showed significantly negative correlation (P<0.05) between crab and sediment samples. The aforementioned evidences suggested that no heavy metal contamination was found in both water and sediment habitats of the purse seine culture area of Chinese mitten crabs in the Yangcheng Lake, and certain correlations were observed between the crabs and the culture habitat in the Yangcheng Lake.

  Toxicity of Hydrogen Sulfide to Zoea Larvae, Mysis Larvae and Postlarvae of Penaeus monodon GUAN Liping, MAI Guanhua, CHEN Pengzheng, WEN Zhenzhong, SUN Chengbo 2023, 39 (6):  152-156.  DOI: 10.11924/j.issn.1000-6850.casb2022-0328 Abstract + ( 191 )   HTML ( 2 )   PDF ( 1054KB )   ( 19 ) The toxicity of hydrogen sulfide to zoea larvae, mysis larvae and postlarvae of Penaeus monodon was discussed to find out the safe concentration for strengthening water quality management during healthy development of nursery production. Conventional biotoxicity test was adopted to test the toxicity of hydrogen sulfide on zoea larvae, mysis larvae and postlarvae of P. monodon and calculate the LC50 and SC for each period. The LC50 at 24, 48, 72 and 96 h was 0.856, 0.720, 0.413 and 0.377 mg/L respectively during the zoea larvae of P. monodon; the LC50 at 24, 48, 72 and 96 h was 5.167, 4.460, 1.387 and 0.940 mg/L respectively during the mysis larvae of P. monodon; and the LC50 at 24, 48, 72 and 96 h was 20.625, 17.813, 12.056 and 10.762 mg/L respectively during the period of P. monodon postlarvae. The safe concentration (CS) of hydrogen sulfide for the zoea larvae, mysis larvae and postlarvae of P. monodon was 0.038, 0.094 and 1.076 mg/L, respectively. Hydrogen sulfide showed different degrees of toxicity with increasing concentration to zoea larvae, mysis larvae and postlarvae of P. monodon.

  Sensitivity and Effectiveness Evaluation of Environmental DNA Metabarcoding for Monitoring Fish Species Diversity in Stream and Reservoir Waters XIE Zhigang, RUAN Gao 2023, 39 (6):  157-164.  DOI: 10.11924/j.issn.1000-6850.casb2022-0317 Abstract + ( 191 )   HTML ( 8 )   PDF ( 1386KB )   ( 45 ) Environmental DNA metabarcoding (eDNA metabarcoding) is a fast, efficient and environmentally friendly method to investigate the diversity of fish species, but its sensitivity and reliability remain to be further evaluated. In this study, Gaobi Stream and Chengping Reservoir, located in the source region of Songyin Stream, a first level tributary of Oujiang River, were selected as the investigated waters, and the survey on fish species distributed in those two waters was carried out by traditional capture-based method and eDNA metabarcoding technology, respectively. The results showed that a total of 24 species of fish were found in the two waters by capture-based method, 88% (21 species) of fish species were recorded in the Oujiang River system. 12 fish species belonging to 4 orders, 8 families, and 11 genera were collected from Gaobi River, and 16 species of fish belonging to 3 orders, 4 families and 14 genera were collected from Chengping Reservoir. A total of 31 species were detected in the two waters by eDNA metabarcoding technology, and 84% (26 species) of fish species were recorded in the Oujiang River system. 28 fish species were found in Gaobi Stream, belonging to 5 orders, 12 families and 25 genera, and 27 species were found in Chengping Reservoir, belonging to 6 orders, 11 families, and 25 genera. However, the two survey methods found only one fish species together in the stream water and only five in the reservoir water. In addition, Shannon diversity index, Simpson diversity index, Margalef’s richness index and Pielou’s evenness of Gaobi Sream were higher than those of Chengping Reservoir, and the conclusions of the two survey methods were relatively consistent. In conclusion, eDNA metabarcoding can find more species and has higher sensitivity than the traditional method, but its results of fish species composition have a marked deviation from those of actual capture. Therefore, eDNA metabarcoding technology can only be used as reference for traditional fishery survey methods at present, and it is necessary to be cautious in drawing survey conclusions by using this technology.