2020 Vol. 19 No. 12 Previous Issue    Next Issue

    Section 1: Crop production and marketing
    Section 2: Livestock production and marketing
    Section 3: Food purchasing behavior and agricultural export
    Section 4: Rural poverty and policy responses
    Crop Science
    Plant Protection
    Animal Science · Veterinary Medicine

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    Editorial- Impacts of COVID-19 on agriculture and rural poverty in China
    HUANG Ji-kun
    2020, 19(12): 2849-2853.  DOI: 10.1016/S2095-3119(20)63469-4
    Abstract ( )   PDF in ScienceDirect  
    Section 1: Crop production and marketing
    Vegetable production under COVID-19 pandemic in China: An analysis based on the data of 526 households
    ZHOU Jie-hong, HAN Fei, LI Kai, WANG Yu
    2020, 19(12): 2854-2865.  DOI: 10.1016/S2095-3119(20)63366-4
    Abstract ( )   PDF in ScienceDirect  
    The COVID-19 pandemic had an enormous impact on the vegetable supply chain in China.  Effective evaluation of the pandemic’s influences on vegetable production is vital for policy settings to enhance the security of vegetable supply.  Based on first-hand data from 526 households, we explored regional differences in different types of loss and potential factors affecting the severity farmer households suffered during the pandemic.  The results underline that sales contraction and price volatility in the context of interruption of supply chain dominate the total losses during the pandemic.  Such losses differ across provinces and are more substantial in provinces with stricter confinement measures.  Farmer households’ participation in local market and modern marketing methods helps mitigate the negative effects of the COVID-19 shock, while labor hiring and facilities adoption in production widen the losses due to the shortage in the workforce.  In the future, the vegetable industry practitioners and relevant government departments should work together to coordinate the development of short and long supply chains and strengthen the stability and security of the vegetable supply chain.
    Impacts of the COVID-19 pandemic on vegetable production and countermeasures from an agricultural insurance perspective
    GU Hai-ying, WANG Chang-wei
    2020, 19(12): 2866-2876.  DOI: 10.1016/S2095-3119(20)63429-3
    Abstract ( )   PDF in ScienceDirect  
    In the face of the corona virus disease 2019 (COVID-19) pandemic, it is essential to stabilize the security of urban “shopping baskets”.  Through a survey and interviews with 46 agricultural cooperatives in Shanghai, this paper analyzes the impact of the pandemic on vegetable production and offers suggestions on agricultural insurance.  The research results show that: (1) the pandemic has impacted almost all stages of the vegetable supply chain but has had a greater impact on the sales stage; (2) the market risks of vegetable production have increased significantly, and the gap between the field price and the market price has widened.  The sales price difference between traditional channels and e-commerce is notable; (3) farmers’ incomes have generally declined due to the COVID-19 pandemic, and traditional small-scale farmers have suffered more losses; and (4) agricultural insurance plays an important role in stabilizing the supply of vegetables to the city.  To minimize the impact of the pandemic on vegetable production and to stabilize both urban “shopping baskets” and farmers’ incomes, it is necessary to further improve agricultural insurance, especially to provide insurance against market risks.
    The short- and long-term impacts of the COVID-19 pandemic on family farms in China-Evidence from a survey of 2 324 farms
    DU Zhi-xiong, LAI Xiao-dong, LONG Wen-jin, GAO Liang-liang
    2020, 19(12): 2877-2890.  DOI: 10.1016/S2095-3119(20)63390-1
    Abstract ( )   PDF in ScienceDirect  
    Family farms are considered the most desirable form of Chinese agriculture.  Studies on the risk management of family farms are rare, while the COVID-19 pandemic provides an opportunity to explore how family farms respond to risks.  Based on an online survey of 2 324 family crop farms, we examine for the first time the short-term impact (immediate impact or short-term fluctuation, and farms’ instantaneous response) and long-term impact (on farms’ future or long-term production) of the COVID-19 pandemic on family farms’ production and operation in rural China.  By using factor analysis and dummy variable regression, we find that the severity of the pandemic, the lockdown of the village, and farmers’ knowledge of the pandemic contribute significantly to the short-term impact, but not on the long-term impact.  Farmers’ characteristics such as gender, age, and education are not related to the short-term impact, but family farms with male owners or owners with high school education or below are more likely to be diversified and large-scale.  The number of years the farm has existed for and agricultural insurance affect both short-term and long-term impacts.  We suggest that the government needs to pay more attention to stability-enhancing policies, the market environment, vocational training and the agricultural insurance market.
    Section 2: Livestock production and marketing
    Pig farmers’ willingness to recover their production under COVID-19 pandemic shock in China-Empirical evidence from a farm survey
    ZHUO Ni, JI Chen, DING Jing-yu
    2020, 19(12): 2891-2902.  DOI: 10.1016/S2095-3119(20)63411-6
    Abstract ( )   PDF in ScienceDirect  
    Pig farmers’ willingness to recover production under the COVID-19 pandemic shock is significant to recover live pigs’ supply in China in 2020.  Increasing farmers’ willingness to recover pig production contributes to enhance pig supply, stabilize the pig and pork market, and to improve pig farmers’ income.  This research studies the determinants of pig farmers’ willingness to recover production under COVID-19 pandemic shock by applying survey data of 201 farmers in Huai’an City and Lin’an City and a logit regression model.  The estimation results show that a farmer’s risk perception, the duration time of a farmer’s feed supply under COVID-19 pandemic shock, whether or not being a cooperative member, and a farmer’s knowledge on government’s policy designed to encourage pig production, a farmer’s education level and production experience are the key determinants to a farmer’s willingness to recover pig production.  Thus, it’s important for policymakers to solve the problems for farmers to get access to feed during the pandemic, to encourage the development of cooperatives, as well as to issue and advocate policies to encourage pig production.  The study contributes to the scant literature by providing fresh empirical evidences on determinants of farmers’ willingness to recover pig production.  It has significance to farmers and governments to enhance farmers’ willingness to recover production, which contributes to secure pig supply in China after the COVID-19 pandemic.
    Impacts of the COVID-19 pandemic on the dairy industry: Lessons from China and the United States and policy implications
    Qingbin WANG, LIU Chang-quan, ZHAO Yuan-feng, Anthony KITSOS, Mark CANNELLA, WANG Shu-kun, HAN Lei
    2020, 19(12): 2903-2915.  DOI: 10.1016/S2095-3119(20)63443-8
    Abstract ( )   PDF in ScienceDirect  
    The purposes of this study are to assess the COVID-19 pandemic’s impacts on the dairy industries in China and the United States and to derive policy recommendations for enhancing the diary industries’ resilience to pandemics and other market shocks.  Specifically, data from the two nations are used to analyze and compare the mechanisms through which the pandemic has affected their dairy industries and to discuss potential lessons from their experiences.  The findings suggest that this pandemic has heavily affected the dairy industries in both China and the United States through similar mechanisms, such as decreased farmgate milk prices, disruption and difficulties of moving milk within the supply chains, worker shortages, increased production costs, and lack of operating capital.  There were also significant differences in the affecting mechanisms between the two nations, including transportation difficulties from widespread road closures and significant reduction in holiday sales of dairy products in China, and the shutdown of many dairy processors in the United States due to the closing of schools, restaurants, and hotels.  While government financial reliefs are highly needed to help many dairy farms and processors survive this pandemic in the short term, the dairy industries and governments need to work together to develop long-term strategies and policies to balance the industries’ efficiency and flexibility, product specialization and diversification, supply chain integration and local food systems, and market mechanisms and policy regulations and interventions. 
    Section 3: Food purchasing behavior and agricultural export
    Panic buying? Food hoarding during the pandemic period with city lockdown
    H. Holly WANG, HAO Na
    2020, 19(12): 2916-2925.  DOI: 10.1016/S2095-3119(20)63448-7
    Abstract ( )   PDF in ScienceDirect  
    Food hoarding is prevalent during the COVID-19 pandemic.  To investigate the mechanism of urban consumers’ food hoarding behaviors, we categorize hoarding motives into rational and irrational ones.  Using random online survey samples from three cities in China, we employ the multivariate probit model to investigate the rational and irrational motives on food hoarding behavior.  Our results confirmed the existence of both rational and irrational food hoarding, and also found factors attributing to the different buying behaviors.  The amount of food at hand and the expectation on the infection possibility of COVID-19 are two major factors affecting rational hoarding.  Bad mood and herd psychology are factors contributing to panic buying.  This study provides an empirical evidence to support intervention policies aiming at mitigating panic buying behavior. 
    Impacts of the COVID-19 pandemic on consumers’ food safety knowledge and behavior in China
    MIN Shi, XIANG Cheng, ZHANG Xiao-heng
    2020, 19(12): 2926-2936.  DOI: 10.1016/S2095-3119(20)63388-3
    Abstract ( )   PDF in ScienceDirect  
    This study assesses the impacts of the COVID-19 pandemic on Chinese residents’ food safety knowledge and behavior, and explores the possible influence mechanism, namely, focus on media information.  The study is based on internet survey data of 1 373 residents in China.  A series of econometric models are developed to estimate food safety knowledge and behavior of residents.  Both the descriptive and econometric results indicate that the existence of COVID-19 cases in a community has a significantly positive effect on residents’ food safety knowledge and behavior.  Residents focusing on food safety-related information tend to have higher food safety knowledge and practice food safety behavior.  When controlling the variable focused on food safety-related information, the marginal effects of the existence of COVID-19 cases in a community on residents’ food safety knowledge and behavior significantly decrease.  However, the decrease in consumers’ food safety knowledge is quite minor.  Hence, the COVID-19 pandemic indeed improves Chinese residents’ food safety knowledge and behavior, while focus on food safety-related information is an important mechanism for improving food safety behavior.  Moreover, the estimation results of the simultaneous equations model reveal that consumers’ food safety knowledge has a significant and positive effect on their food safety behavior.  Heterogeneous impacts of the COVID-19 pandemic on residents’ food safety knowledge and behavior among different regions and income groups are observed.  The findings of this study provide evidence that public health events could enhance residents’ safety awareness and behavior, while residents’ focus on relevant information plays an important role in improving knowledge and impacting behavior.
    Impact of the COVID-19 pandemic on agricultural exports
    LIN Ben-xi, Yu Yvette ZHANG
    2020, 19(12): 2937-2945.  DOI: 10.1016/S2095-3119(20)63430-X
    Abstract ( )   PDF in ScienceDirect  
    The COVID-19 outbreak has shocked the world’s economies in the year of 2020.  As this pandemic spreads around the globe, many experts feared that the global food supplies might start running short, especially if supply chains were disrupted.  COVID-19 also added to the uncertainty of the business operation.  Therefore, it is critical to understand how COVID-19 pandemic affected global food supply and market.  In this study, we investigate the impact of COVID-19 on agricultural export companies in China using a unique firm-level survey data.  We found that although on average agricultural businesses experienced declines in the exports, exports of some agricultural products especially grain and oil held strong and even increased, implying the essential demand for staple food during the pandemic.  Not surprisingly, exports of medicinal herb also increased significantly during the pandemic.  However, exports of goods such as edible fungus and horticultural products sharply decreased.  Our results also showed that in general, impact of COVID-19 on smaller firms was more severe than that on larger firms.  The results of this study can provide useful guidance and implications for agricultural businesses and policy makers on their COVID-19 mitigation efforts to navigate this global pandemic.
    Section 4: Rural poverty and policy responses
    Impacts of the COVID-19 pandemic on rural poverty and policy responses in China
    LUO Ren-fu, LIU Cheng-fang, GAO Jing-jing, WANG Tian-yi, ZHI Hua-yong, SHI Peng-fei, HUANG Ji-kun
    2020, 19(12): 2946-2964.  DOI: 10.1016/S2095-3119(20)63426-8
    Abstract ( )   PDF in ScienceDirect  
    Given the sudden outbreak of the COVID-19 pandemic, a timely study on the impacts of and policy response to the pandemic on rural poverty in China is critically important because China has aimed to completely eradicate extreme poverty by the end of 2020.  This paper uses data from the latest round of a nationally representative household panel survey to examine the impacts of the pandemic on rural poverty in China.  Our data show that 11.9% of sample households were ever officially registered as poor households between 2013 and 2019, and this poverty incidence fell to 2.7% by the end of 2019.  In the middle February of 2020, 23% of the households who have graduated from poverty since 2013 perceived that they would fall back into poverty due to the COVID-19.  Among those never poor households, 7.1% perceived that they would possibly fall into poverty due to the pandemic.  Results from both descriptive and multivariate analyses consistently show the interruptions that the pandemic caused in off-farm employment is an important channel that led households to perceive of falling back into or falling into poverty.  We also find households in the bottom four quintiles when ranked in terms of household income per capita are much more likely to perceive themselves of falling back into or falling into poverty during this pandemic than those in the richest quintile.  Meanwhile, our results show that the education and age of household heads, as well as being from Hubei Province matter in explaining household perception about falling back into or falling into poverty in some cases but not all.  The paper concludes with a set of policy responses that China has taken to mitigate the impact of COVID-19 pandemic on poverty alleviation. 
    Crop Science
    Breeding of CMS maintainer lines through anther culture assisted by high-resolution melting-based markers
    WANG Ping, BAI Yu-lu, WANG Min-xia, HU Bin-hua, PU Zhi-gang, ZHANG Zhi-yong, ZHANG Qiong, XU Deng-wu, LUO Wen-long, CHEN Zhi-qiang
    2020, 19(12): 2965-2973.  DOI: 10.1016/S2095-3119(20)63179-3
    Abstract ( )   PDF in ScienceDirect  
    The integrated use of molecular marker-assisted selection (MAS) and anther culture has potential to significantly increase efficiency in plant breeding; however, reports on this kind of practical use are very limited.  In the present study, we report the development of cytoplasmic male sterile (CMS) maintainers with aroma, disease resistance and red-brown hulls, as an example of integration of MAS and anther culture in rice breeding.  A high-resolution melting (HRM)-based functional molecular marker was developed for the red-brown hull trait caused by a unique mutation (rbh1) in OsCAD2.  Functional molecular markers for genes of rice blast resistance (Pi2), aroma (fgr) and red-brown hull (rbh1) were used for precise genotyping of individual plants in the BC1 and BC2F2 populations derived from a cross between CMS maintainers Huaxiang B (pi2–/rbh1–/fgr–) and Rong 3B (Pi2+/RBH1+/Fgr+).  A total of 89 doubled haploid (DH) lines were generated from selected BC2F2 plants (Pi2+/rbh1–/fgr–) by anther culture.  Seven DH lines were subsequently selected as the potential new CMS maintainers based on their overall performance and high resistance to blast.  Our study demonstrated that integration of MAS and anther culture significantly accelerated the development of CMS maintainers with multiple stacked genes.
    Development of peanut varieties with high oil content by in vitro mutagenesis and screening
    WANG Jing-shan, SHI Lei, LIU Yue, ZHAO Ming-xia, WANG Xia, QIAO Li-xian, SUI Jiong-ming, LI Guan, ZHU Hong, YU Shan-lin
    2020, 19(12): 2974-2982.  DOI: 10.1016/S2095-3119(20)63182-3
    Abstract ( )   PDF in ScienceDirect  
    Peanut (Arachis hypogaea L.) is an important oil crop globally and high oil content is one of the major targets in peanut breeding programs.  Previous studies indicated that the osmotic pressure (OP) of the leaves of peanut plants subjected to drought stress was negatively correlated with kernel oil content.  Based on this knowledge, we established a practical and reliable method for creating new peanut varieties with high oil content using in vitro mutagenesis and directional OP-based selection.  Using embryonic leaflets of peanut variety Huayu 20 as explants, pingyangmycin (PYM) as the mutagen, and hydroxyproline (HYP) as the OP regulator, we developed 15 HYP-tolerant regenerated plants.  For each regenerated plant, we selected offspring with oil content>55% (relative to 49.5% for Huayu 20).  We developed and released three new peanut varieties with high yield and high oil content from the offspring of the HYP-tolerant regenerated plants.  The three new varieties were named as Yuhua 4, Yuhua 9 and Yuhua 14 and their oil contents were 57.7, 61.1 and 59.3%, respectively.  The results indicate that in vitro mutagenesis with PYM followed by directed screening with HYP is a useful approach for breeding peanut varieties with high oil contents.
    Changes in starch quality of mid-season indica rice varieties in the lower reaches of the Yangtze River in last 80 years
    ZHANG Hao, JING Wen-jiang, XU Jing-ju, MA Bing-ju, WANG Wei-lu, ZHANG Wei-yang, GU Jun-fei, LIU Li-jun, WANG Zhi-qin, YANG Jian-chang
    2020, 19(12): 2983-2996.  DOI: 10.1016/S2095-3119(20)63431-1
    Abstract ( )   PDF in ScienceDirect  
    Rice (Oryza sativa L.) quality depends mainly on the characteristics of starch stored in kernels.  Understanding the changes in starch characteristics in kernels during variety improvement would have great significance to improve rice quality.  This study was designed to investigate the starch characteristics in the kernels and associated physiological traits of indica rice varieties in the lower reaches of the Yangtze River in China in last 80 years.  Eight representative mid-season indica rice varieties were grown in the field.  The results showed that the grain yield was significantly increased with the improvement of varieties and such an increase was mainly attributed to the increase in total number of spikelets.  The tall varieties applied in the 1940s–1950s had higher protein content, relative crystallinity and infrared (IR) ratio of 1 045/1 022 cm–1.  The semi-dwarf varieties applied in the 1980s–1990s had higher gel consistency, amylopectin content, IR ratio of 1 022/995 cm–1, and breakdown value.  With the improvement of varieties, the amylose content, large-sized starch granule number and volume distribution, onset and peak of gelatinization temperature, gelatinization and retrogradation enthalpy, setback value, pasting temperature, viscosity of peak, hot and final, and 1-aminocycopropane-1-carboxylic acid (ACC) concentrations in panicles and root bleeding were gradually decreased, whereas the medium-sized starch granule number and volume distribution, activities of key enzymes in grains, and zeatin (Z)+zeatin riboside (ZR) contents in panicles and root bleeding at grain filling stage were gradually increased.  Correlation analysis showed that starch thermodynamic characteristics were closely related to starch structure and components, key enzymes and hormones.  The results suggest that starch quality was enhanced through the optimization of starch components, structure, thermodynamics, and the regulation of key enzymes in grains and hormones in panicles and root bleedings at grain filling stage during the improvement of mid-season indica rice.
    Innovation of the double-maize cropping system based on cultivar growing degree days for adapting to changing weather conditions in the North China Plain
    WANG Dan, LI Guo-rui, ZHOU Bao-yuan, ZHAN Ming, CAO Cou-gui, MENG Qing-feng, XIA Fei, MA Wei, ZHAO Ming
    2020, 19(12): 2997-3012.  DOI: 10.1016/S2095-3119(20)63213-0
    Abstract ( )   PDF in ScienceDirect  
    Double-maize cropping system is an effective option for coping with climate change in the North China Plain.  However, the effects of changes in climate on the growth and yield of maize in the two seasons are poorly understood.  Forty-six cultivars of maize with different requirements for growing degree days (GDD), categorized as high (H), medium (M) or low (L), and three cultivar combinations for two seasons as LH (using JD27 and DMY1 from category L in the first season; and YD629 and XD22 from category H in the second season), MM (using JX1 and LC3 from category M in the first season; and ZD958 and JX1 from category M in the second season) and HL (using CD30 and QY9 from category H in the first season; and XK10 and DMY3 from category L in the second season) were tested to examine the eco-physiological determinants of maize yield from 2015 to 2017.  The correlations between the combinations of cultivars and grain yield were examined.  The combination LH produced the highest annual grain yield and total biomass, regardless of the year.  It was followed, in decreasing order, by MM and HL.  Higher grain yield and biomass in LH were mainly due to the greater grain yield and biomass in the second season, which were influenced mainly by the lengths of the pre- and post-silking periods and the rate of plant growth (PGR).  Temperature was the primary factor that influenced dry matter accumulation.  In the first season, low temperatures during pre-silking decreased both the duration and PGR in LH, whereas high temperatures during post-silking decreased the PGR in MM and HL, resulting in no significant differences in biomass being observed among the three combinations.  In the second season, high temperatures decreased both the PGR and pre- and post-silking duration in MM and HL, and consequently, the biomass of those two combinations were lower than that in LH.  Moreover, because of lower GDD and radiation in the first season and higher grain yield in the second season, production efficiency of temperature and radiation (Ra) was the highest in LH.  More importantly, differences in temperature and radiation in the two seasons significantly affected the rate and duration of growth in maize, and thereby affecting both dry matter and grain yield.  Our study indicated that the combination of LH is the best for optimizing the double-maize system under changing climatic conditions in the North China Plain.
    Plant Protection
    Overview of purple blotch disease and understanding its management through chemical, biological and genetic approaches
    Aejaz Ahmad DAR, Susheel SHARMA, Reetika MAHAJAN, Muntazir MUSHTAQ, Ankila SALATHIA, Shahid AHAMAD, Jag Paul SHARMA
    2020, 19(12): 3013-3024.  DOI: 10.1016/S2095-3119(20)63285-3
    Abstract ( )   PDF in ScienceDirect  
    Purple blotch disease of Allium spp. crops caused by Alternaria porri has remained a major concern in agriculture for both farmers and research fraternity as it severely damages the crops and drastically reduces the yield.  The symptoms appear after 1–4 days of infection and bulb rot begin, and eventually turn into dark reddish-purple and then brownish/black lesions.  Many factors like season, time of sowing, humidity and temperature, stage of crop, and plant architecture have a huge impact on the progression of purple blotch disease.  Many genic markers based on amplification of an Alta1 gene sequence have been designed for identification and differentiation of different Alternaria species groups.  Among the most commonly used fungicides, mancozeb, tebuconazole, difenaconazole and azoxystrobin were found to be the ideal for the management of purple blotch disease and increased garlic yield.  Many biological approaches such as plant extracts and bio-control agents were found partially effective for controlling the disease.  A report on QTL mapping for purple blotch resistance discovered that purple blotch resistance is controlled by a single dominant gene ApR1.  To completely understand the purple blotch disease resistance for crop improvement, a study is required at transcriptome level for hunting purple blotch resistant genes by gene annotation and mining.  Genetic engineering and genome editing are other approaches that can be done for engineering disease resistance in Allium crops for genetic improvement.
    Cloning and functional characterization of two peptidoglycan recognition protein isoforms (PGRP-LC) in Bactrocera dorsalis (Diptera: Tephritidae)
    WEI Dong, WANG Zhe, XU Hui-qian, NIU Jin-zhi, WANG Jin-jun
    2020, 19(12): 3025-3034.  DOI: 10.1016/S2095-3119(20)63202-6
    Abstract ( )   PDF in ScienceDirect  
    The innate immune system of insects is the front line of self-defense against pathogen invasion.  Peptidoglycan recognition proteins (PGRPs) are important components and play key roles in insect immune systems by recognizing peptidoglycan (PGN) in bacterial cell walls.  We characterized two isoforms of the PGRP-LC gene, BdPGRP-LCa and BdPGRP-LCb, from Bactrocera dorsalis (Hendel), an important fruit and vegetable pest worldwide.  These two isoforms contain an open reading frames of 1 668 bp and 1 731 bp, encoding a protein of 555 and 576 amino acids, respectively.  Quantitative real-time PCR results showed that both transcripts were prominently expressed in midgut and fat body of B. dorsalis adult.  Inoculation of pathogens showed that both isoforms actively responded to Escherichia coli PGN.  We also observed a light response to Staphylococcus aureus PGN.  Upon Beauveria bassiana inoculation, the expression of BdPGRP-LCa was enhanced, but the expression of BdPGRP-LCb was suppressed.  Suppression of both transcripts by RNA interference led to increased mortality of flies challenged by E. coli, indicating that the two isoforms are involved in sensing Gram-negative bacterial infections.
    Attraction of bruchid beetles Callosobruchus chinensis (L.) (Coleoptera: Bruchidae) to host plant volatiles
    WANG Hong-min, BAI Peng-hua, ZHANG Jing, ZHANG Xue-min, HUI Qin, ZHENG Hai-xia, ZHANG Xian-hong
    2020, 19(12): 3035-3044.  DOI: 10.1016/S2095-3119(20)63237-3
    Abstract ( )   PDF in ScienceDirect  
    Host-plant volatiles play an important role as cues for herbivores in search of resources, mates and oviposition sites in complex environments.  Plant volatile-based attractants can be developed for pest monitoring and control.  Previously, we indicated that mated female adults of Callosobruchus chinensis showed choice preference behavior toward 2-hexenal and benzaldehyde.  Our objective here was to investigate the synergistic effect of host-derived attractive volatiles in attracting C. chinensis under laboratory and field conditions in Shanxi Province, China.  We hypothesized that the ratio and concentration of volatiles derived from Vigna radiata play critical roles for C. chinensis in locating this host.  Therefore, we collected and identified the volatiles of mungbean by using headspace collection and GC-MS.  The effectiveness of different ratios and concentrations of two compounds (2-hexenal and benzaldehyde) that elicit C. chinensis searching behavior were examined in Y-tube olfactometer assays.  The combination of 300 μg μL–1 2-hexenal and 180 μg μL–1 benzaldehyde loadings exhibited a synergistic effect on attracting C. chinensis (82.35%).  Compared to control traps, the adults were significantly attracted to traps baited with blends, and more attraction to females than males was found for blend traps in the field experiments.  Our results suggest that blends of this specific concentration and ratio of benzaldehyde and 2-hexenal can be used in traps as attractants for C. chinensis monitoring and control in the field.
    Application of imidacloprid controlled-release granules to enhance the utilization rate and control wheat aphid on winter wheat
    YUAN Wan-ling, XU Bo, RAN Gang-chao, CHEN Hui-ping, ZHAO Peng-yue, HUANG Qi-liang
    2020, 19(12): 3045-3053.  DOI: 10.1016/S2095-3119(20)63240-3
    Abstract ( )   PDF in ScienceDirect  
    During winter wheat production, aphids need to be controlled with pesticides for the entire growth period.  Controlled-release technology has been regarded as an alternative method for the improvement of pesticide efficiency.  This study investigated two types of imidacloprid controlled-release granule (CR-GR): 2% imidacloprid CR-GR and 0.2% imidacloprid pesticide-fertilizer controlled-release granule (PF-CR-GR) when wheat was sown in winter.  The release performance, utilization rate, terminal residues in edible parts, control effect on aphids, and achieved winter wheat yield were evaluated for both laboratory experiments and field application.  Imidacloprid PF-CR-GR released more quickly in aqueous medium than CR-GR because of its good water solubility.  After CR-GR treatments, the concentrations in wheat roots and soil were similar throughout the entire sampling period, and the concentrations in shoots were about 10–20% of those in roots.  Imidacloprid was better absorbed when CR-GR was used as root treatment, compared with foliar treatment.  Field application showed that imidacloprid CR-GR and PF-CR-GR controlled aphids throughout the entire growth period of winter wheat and improved the wheat yield.  These findings identified application of imidacloprid CR-GR and PF-CR-GR on winter wheat as an effective way to enhance the pesticide utilization rate and ensure adequate yield.  This paper provides a theoretical basis for the scientific use of pesticides and guides scientific pesticide application.
    Animal Science · Veterinary Medicine
    The expression of Lin28B was co-regulated by H3K4me2 and Wnt5a/β-catenin/TCF7L2
    ZHANG Ya-ni, HU Cai, WANG Ying-jie, ZUO Qi-sheng, LI Bi-chun
    2020, 19(12): 3054-3064.  DOI: 10.1016/S2095-3119(20)63441-4
    Abstract ( )   PDF in ScienceDirect  
    Lin28A and Lin28B are homologous RNA-binding proteins that participate in the development of primordial germ cells.  The mechanisms underlying expression and regulation of Lin28A have been well documented, but such information for Lin28B is limited.  In this study, a fragment of the Lin28B promoter was cloned, the pEGFP-pLin28B vector was constructed.  DF-1 chicken fibroblasts were transfected and the expression of green fluorescent protein (GFP) was measured.  Furtherly, Lin28B promoter of different lengths fragments was cloned using the chromosome-walking method and the fragments were ligated into the PGL3-Basic vector, and transfected into DF-1 cells.  Results of dual-luciferase reporter assay showed that the core of the Lin28B promoter was included in the sequence from –1 431 to –1 034 bp.  The binding sites of the transcription factor TCF7L2 was showed within this sequence by bioinformatics analysis.  The promoter activity of Lin28B was downregulated (P<0.05) when the TCF7L2 binding site was mutated.  Further experiments suggested that Lin28B promoter activity responded to the activation or inhibition of Wnt signaling.  Results of chromatin immunoprecipitation and quantitative PCR showed that β-catenin-TCF7L2 may be enriched in the Lin28B promoter core area.  In vivo and in vitro activation or inhibition of Wnt signaling significantly up- or down-regulated (P<0.05) Lin28B expression.  H3K4me2 enriched in the promoter of Lin28B, which affected the regulation of Wnt signaling to Lin28B.  In conclusion, our results showed that H3K4me2 and Wnt5a/β-catenin/TCF7L2 were the positive regulators of Lin28B expression.  Findings of this study may lay a theoretical foundation for illuminating the mechanism underlying Lin28B expression.
    The tissue expression level of BPI gene in piglets from newborn to weaning and its relationship with Gram-negative bacterial infection
    DAI Chao-hui, CAO Yue, GAO Zhong-cheng, ZHU Guo-qiang, WU Sheng-long, BAO Wen-bin
    2020, 19(12): 3065-3073.  DOI: 10.1016/S2095-3119(20)63369-X
    Abstract ( )   PDF in ScienceDirect  
    The bactericidal/permeability increasing protein (BPI) has an important function of nonspecific killing of Gram-negative bacteria.  In this study, qPCR was used to detect the expression of the BPI gene in twelve tissues of Meishan piglets from birth to weaning.  BPI gene overexpression, bacterial adhesions count and indirect immunofluorescence were applied to analyze the relationship between BPI gene expression and the infectivity of Escherichia coli and Salmonella.  The results showed that the BPI gene was expressed highly in duodenum, jejunum and ileum (fold changes of relative expression levels were more than 10 000, 500 and 200, respectively).  The expression of the BPI gene at 35 days of age was significantly higher (P<0.01) than that at all other days.  Transcription of the BPI gene was up-regulated 2 401-fold in porcine intestinal epithelial (IPEC-J2) cells that were transfected with the BPI gene overexpression lentivirus (IPEC-J2-BPI), and significantly higher (P<0.01) than that in negative control cells (IPEC-J2-NC).  Protein expression levels in IPEC-J2-BPI cells were also increased.  When IPEC-J2 cells were incubated with E. coli and Salmonella, respectively, for 2, 4, 6, 8, 10 and 12 h, the number of bacterial adhesions in IPEC-J2-BPI cells was significantly less (P<0.05) than that in IPEC-J2-NC cells.  The results of indirect immunofluorescence analysis showed that the number of bacterial adhesions in IPEC-J2-BPI cells was significantly less (P<0.01) than that in IPEC-J2-NC cells.  These results demonstrated that the BPI gene might play an important role in regulating weaning stress especially intestinal-mediated immune response.  Overexpression of the BPI gene at the cellular level could significantly enhance the anti-bactericidal ability against Gram-negative bacteria such as E. coli and Salmonella.  This has important biological significance in piglet resistance to bacterial diarrhea.