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2023 Vol. 22 No. 6 Previous Issue   

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Crop Science
Horticulture
Plant Protection
Animal Science · Veterinary Medicine
Agro-ecosystem & Environment
Agricultural Economics and Management
Letter


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Cover illustration


High-molecular-weight glutenin subunits (HMW-GSs) are the most critical grain storage proteins that determine the unique processing qualities of wheat. Although it is a part of the superior HMW-GS pair (Dx5+Dy10), the contribution of the Dy10 subunit to wheat processing quality remains unclear. In this study, we elucidated the effect of Dy10 on wheat processing quality by generating and analyzing a deletion mutant (with the Dy10-null allele), and by elucidating the changes to wheat flour following the incorporation of purified Dy10. Based on an analysis of this mutant, we demonstrated that the Dy10 subunit is essential for maintaining dough strength. Furthermore, the Dy10-null allele positively affects the biscuit-making quality of wheat dough, making it potentially useful for soft wheat breeding programs. The cover photo depicts the formation process of wheat end-use quality, provided by the research team of Prof. Qi Pengfei and Dr. Wang Yan from Triticeae Research Institute, Sichuan Agricultural University, China. See pages 1609–1617 for details.


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Crop Science

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Effect of high-molecular-weight glutenin subunit Dy10 on wheat dough properties and end-use quality WANG Yan, GUO Zhen-ru, CHEN Qing, LI Yang, ZHAO Kan, WAN Yong-fang, Malcolm J. HAWKESFORD, JIANG Yun-feng, KONG Li, PU Zhi-en, DENG Mei, JIANG Qian-tao, LAN Xiu-jin, WANG Ji-rui, CHEN Guo-yue, MA Jian, ZHENG You-liang, WEI Yu-ming, QI Peng-fei 2023, 22(6): 1609-1617.  DOI: 10.1016/j.jia.2022.08.041 Abstract ( )   PDF in ScienceDirect   High-molecular-weight glutenin subunits (HMW-GSs) are the most critical grain storage proteins that determine the unique processing qualities of wheat. Although it is a part of the superior HMW-GS pair (Dx5+Dy10), the contribution of the Dy10 subunit to wheat processing quality remains unclear. In this study, we elucidated the effect of Dy10 on wheat processing quality by generating and analyzing a deletion mutant (with the Dy10-null allele), and by elucidating the changes to wheat flour following the incorporation of purified Dy10. The Dy10-null allele was transcribed normally, but the Dy10 subunit was lacking. These findings implied that the Dy10-null allele reduced the glutenin:gliadin ratio and negatively affected dough strength (i.e., Zeleny sedimentation value, gluten index, and dough development and stability times) and the bread-making quality; however, it positively affected the biscuit-making quality. The incorporation of various amounts of purified Dy10 into wheat flour had a detrimental effect on biscuit-making quality. The results of this study demonstrate that the Dy10 subunit is essential for maintaining wheat dough strength. Furthermore, the Dy10-null allele may be exploited by soft wheat breeding programs.

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Variations in chlorophyll content, stomatal conductance and photosynthesis in Setaria EMS mutants TANG Chan-juan, LUO Ming-zhao, ZHANG Shuo, JIA Guan-qing, TANG Sha, JIA Yan-chao, ZHI Hui, DIAO Xian-min 2023, 22(6): 1618-1630.  DOI: 10.1016/j.jia.2022.10.014 Abstract ( )   PDF in ScienceDirect   Chlorophyll (Chl) content, especially Chl b content, and stomatal conductance (Gs) are key factors that greatly affect net photosynthetic rate (Pn).  Setaria italica, a diploid C4 panicoid species with a simple genome and high transformation efficiency, has been widely accepted as a model in photosynthesis and drought-tolerance research.  In the current study, Chl content, Gs, and Pn of 48 Setaria mutants induced by ethyl methanesulfonate were characterized.  A total of 24, 34 and 35 mutants had significant variations in Chl content, Gs, and Pn, respectively. Correlation analysis showed that positive correlation exists between increased Gs and increased Pn, and a weak correlation between decreased Chl b content and decreased Pn was also found. Remarkably, two mutants behaved significantly decreased Chl b content but increased Pn when compared that of Yugu 1. Seven mutants behaved significantly decreased Gs but non-decreasing Pn when compared that of Yugu 1.  The current study thus identified various genetic lines, further exploration of which would be beneficial to elucidate the relationship between Chl content, Gs and Pn and the mechanism underlying why C4 species are efficient at photosynthesis and water saving.

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Raised bed planting promotes grain number per spike in wheat grown after rice by improving spike differentiation and enhancing photosynthetic capacity DU Xiang-bei, XI Min, WEI Zhi, CHEN Xiao-fei, WU Wen-ge, KONG Ling-cong 2023, 22(6): 1631-1644.  DOI: 10.1016/j.jia.2022.08.035 Abstract ( )   PDF in ScienceDirect   The yield of wheat in wheat–rice rotation cropping systems in the Yangtze River Plain, China, is adversely impacted by waterlogging. A raised bed planting (RBP) pattern may reduce waterlogging and increase the wheat yield after rice cultivation by improving the grain number per spike. However, the physiological basis for grain formation under RBP conditions remains poorly understood. The present study was performed over two growing seasons (2018/2019 and 2019/2020) to examine the effects of the planting pattern (i.e., RBP and flat planting (FP)) on the floret and grain formation features and leaf photosynthetic source characteristics of wheat. The results indicated that implementation of the RBP pattern improved the soil–plant nitrogen (N) supply during floret development, which facilitated balanced floret development, resulting in a 9.5% increase in the number of fertile florets per spike. Moreover, the RBP pattern delayed wheat leaf senescence and increased the photosynthetic source capacity by 13.9%, which produced more assimilates for grain filling. Delayed leaf senescence was attributed to the resultant high leaf N content and enhanced antioxidant metabolism. Correspondingly, under RBP conditions, 7.6–8.6% more grains per spike were recorded, and the grain yield was ultimately enhanced by 10.4–12.7%. These results demonstrate that the improvement of the spike differentiation process and the enhancement of the leaf photosynthetic capacity were the main reasons for the increased grain number per spike of wheat under the RBP pattern, and additional improvements in this technique should be achievable through further investigation.

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Mapping winter rapeseed in South China using Sentinel-2 data based on a novel separability index TAO Jian-bin, ZHANG Xin-yue, WU Qi-fan, WANG Yun 2023, 22(6): 1645-1657.  DOI: 10.1016/j.jia.2022.10.008 Abstract ( )   PDF in ScienceDirect   Large-scale crop mapping using remote sensing data is of great significance for agricultural production, food security and the sustainable development of human societies. Winter rapeseed is an important oil crop in China that is mainly distributed in the Yangtze River Valley. Traditional winter rapeseed mapping practices are insufficient since they only use the spectral characteristics during the critical phenological period of winter rapeseed, which are usually limited to a small region and cannot meet the needs of large-scale applications. In this study, a novel phenology-based winter rapeseed index (PWRI) was proposed to map winter rapeseed in the Yangtze River Valley. PWRI expands the date window for distinguishing winter rapeseed and winter wheat, and it has good separability throughout the flowering period of winter rapeseed. PWRI also improves the separability of winter rapeseed and winter wheat, which traditionally have been two easily confused winter crops. A PWRI-based method was applied to the Middle Reaches of the Yangtze River Valley to map winter rapeseed on the Google Earth Engine platform. Time series composited Sentinel-2 data were used to map winter rapeseed with 10 m resolution. The mapping achieved a good result with overall accuracy and kappa coefficients exceeding 92% and 0.85, respectively. The PWRI-based method provides a new solution for high spatial resolution winter rapeseed mapping at a large scale.

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Better tillage selection before ridge–furrow film mulching can facilitate root proliferation, increase nitrogen accumulation, translocation, grain yield of maize in a semiarid area ZHANG Miao-miao, DANG Peng-fei, LI Yü-ze, QIN Xiao-liang, Kadambot-H. M. SIDDIQUE 2023, 22(6): 1658-1670.  DOI: 10.1016/j.jia.2022.08.037 Abstract ( )   PDF in ScienceDirect   Plastic film mulch systems are used widely in arid areas, and the associated tillage measures affect soil properties, root and crop growth, and nutrient uptake.  However, much debate surrounds the most suitable tillage method for plastic film mulch systems.  We conducted a two-year field experiment to explore the impact of three tillage treatments - rotary tillage before ridge–furrow plastic film mulch (MR), no-tillage before ridge–furrow plastic film mulch (MZ), and plow tillage before ridge–furrow plastic film mulch (MP) - on soil total nitrogen, available nitrogen, root stratification structure, nitrogen transfer and utilization, and maize yield.  The results showed that MP had better soil quality than either MR or MZ over 2019 and 2020, with higher nitrate-nitrogen and total nitrogen in the 0–40 cm soil layer.  MP improved the soil physicochemical properties more than the other treatments, producing significantly higher root numbers and root biomass for the aerial and underground nodal roots than MR and MZ.  At harvest, MP had the highest root biomass density, root length density, and root surface area density in the different soil layers (0–20, 20–40, and 0–40 cm).  Significant correlations occurred between root biomass and aboveground nitrogen accumulation during maize growth.  During grain filling, MP had the greatest nitrogen transfer amount, significantly increasing root and aboveground nitrogen transfer by 19.63–45.82% and 11.15–24.56%, respectively, relative to the other treatments.  MP significantly produced 1.36–26.73% higher grain yields and a higher grain crude protein content at harvest than MR and MZ.  MP also had higher values for the nitrogen harvest index, nitrogen uptake efficiency, and partial factor productivity of nitrogen fertilizer than MR and MZ.  In conclusion, plow tillage combined with a ridge–furrow plastic film mulch system facilitated maize root development and improved nitrogen utilization, thereby increasing maize yield more than the other treatments.

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Detection of maize tassels for UAV remote sensing image with an improved YOLOX Model SONG Chao-yu, ZHANG Fan, LI Jian-sheng, XIE Jin-yi, YANG Chen, ZHOU Hang, ZHANG Jun-xiong 2023, 22(6): 1671-1683.  DOI: 10.1016/j.jia.2022.09.021 Abstract ( )   PDF in ScienceDirect   Maize tassel detection is essential for future agronomic management in maize planting and breeding, with application in yield estimation, growth monitoring, intelligent picking, and disease detection.  However, detecting maize tassels in the field poses prominent challenges as they are often obscured by widespread occlusions and differ in size and morphological color at different growth stages.  This study proposes the SEYOLOX-tiny Model that more accurately and robustly detects maize tassels in the field.  Firstly, the data acquisition method ensures the balance between the image quality and image acquisition efficiency and obtains maize tassel images from different periods to enrich the dataset by unmanned aerial vehicle (UAV).  Moreover, the robust detection network extends YOLOX by embedding an attention mechanism to realize the extraction of critical features and suppressing the noise caused by adverse factors (e.g., occlusions and overlaps), which could be more suitable and robust for operation in complex natural environments.  Experimental results verify the research hypothesis and show a mean average precision (mAP@0.5) of 95.0%.  The mAP@0.5, mAP@0.5–0.95, mAP@0.5–0.95 (area=small), and mAP@0.5–0.95 (area=medium) average values increased by 1.5, 1.8, 5.3, and 1.7%, respectively, compared to the original model.  The proposed method can effectively meet the precision and robustness requirements of the vision system in maize tassel detection.

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Enhancing boll protein synthesis and carbohydrate conversion by the application of exogenous amino acids at the peak flowering stage increased the boll Bt toxin concentration and lint yield in cotton LIU Zhen-yu, LI Yi-yang, Leila. I. M. TAMBEL, LIU Yu-ting, DAI Yu-yang, XU Ze, LENG Xin-hua, ZHANG Xiang, CHEN De-hua, CHEN Yuan 2023, 22(6): 1684-1694.  DOI: 10.1016/j.jia.2022.10.003 Abstract ( )   PDF in ScienceDirect   In Bacillus thuringenesis (Bt) transgenic cotton, the cotton boll has the lowest insecticidal protein content when compared to the other organs.  The present study investigated the effects of amino acid spray application at the peak flowering stage on the cotton boll Bt toxin concentration and yield formation.  Boll protein synthesis and carbohydrate conversion were also studied to reveal the fundamental mechanism.  Three treatments (i.e., CK, the untreated control; LA1, five amino acids; LA2, 21 amino acids) were applied to two Bt cultivars of G. hirsutum (i.e., the hybrid Sikang 3 and the conventional Sikang 1) in the cotton-growing seasons during 2017 and 2018.  Amino acid spray application at the peak flowering stage resulted in an increase of 5.2–16.4% in the boll Bt protein concentration and an increase of 5.5–11.3% in the seed cotton yield, but there was no difference between the two amino acid treatments.  In addition, amino acid applications led to increases in the amino acid content, soluble protein content, glutamate pyruvate transaminase (GPT) activity, glutamate oxaloacetate transaminase (GOT) activity, glucose content, fructose content and soluble acid invertase (SAI) activity.  This study also found that Bt protein content, enhanced boll number and the weight of opened bolls were closely related to carbon and nitrogen metabolism.  The Bt protein content had significant linear positive correlations with amino acid and soluble protein contents.  Enhanced boll number had significant linear positive correlations with the GPT and GOT activities from 15–25 days after flowering (DAF).  The weight of opened bolls from 55–65 DAF had a significant linear positive correlation with the SAI activity.  These results indicate that the enhancement of boll protein synthesis and carbohydrate conversion by amino acid application resulted in a simultaneous increase in the boll Bt protein concentration and cotton lint yield.

Horticulture

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Metabolomic and transcriptomic analysis reveals the molecular mechanism by which blue light promotes lutein synthesis in strawberry CHEN Xiao-dong, CAI Wei-jian, XIA Jin, YUAN Hua-zhao, WANG Qing-lian, PANG Fu-hua, ZHAO Mi-zhen 2023, 22(6): 1695-1703.  DOI: 10.1016/j.jia.2023.04.002 Abstract ( )   PDF in ScienceDirect   Carotenoids are an important component of the human diet, and fruit is a primary source of carotenoids.  The synthesis and regulation of carotenoids in fruit are important contributors to the formation of fruit quality.  In China, strawberry is one of the main seasonal fruits grown in the winter.  Previous studies have shown that light has a significant effect on the metabolism of anthocyanins, sugars, and polyphenols in strawberry.  However, the understanding of the role of light in regulating the metabolism of carotenoids in strawberry remains limited.  This study investigated the effects of blue, red, yellow-green, and white light on carotenoid metabolism in strawberry.  Blue light treatment promoted the synthesis of multiple carotenoids, including lutein, compared with the other three treatment groups.  The RNA sequencing data revealed that blue light treatment promoted the expression of lycopene ε-cyclase (LCYE), and the transient overexpression of LCYE in strawberry fruit promoted lutein accumulation in strawberry.  Overall, the results suggest that blue light can promote the synthesis of lutein in strawberry by inducing the expression of LCYE.

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MdWRKY40is directly promotes anthocyanin accumulation and blocks MdMYB15L, the repressor of MdCBF2, which improves cold tolerance in apple XU Peng-yue, XU Li, XU Hai-feng, HE Xiao-wen, HE Ping, CHANG Yuan-sheng, WANG Sen, ZHENG Wen-yan, WANG Chuan-zeng, CHEN Xin, LI Lin-guang, WANG Hai-bo 2023, 22(6): 1704-1719.  DOI: 10.1016/j.jia.2023.04.033 Abstract ( )   PDF in ScienceDirect   Cold stress is an important factor that limits apple production.  In this study, we examined the tissue-cultured plantlets of apple rootstocks ‘M9T337’ and ‘60-160’, which are resistant and sensitive to cold stress, respectively.  The enriched pathways of differentially expressed genes (DEGs) and physiological changes in ‘M9T337’ and ‘60-160’ plantlets were clearly different after cold stress (1°C) treatment for 48 h, suggesting that they have differential responses to cold stress.  The differential expression of WRKY transcription factors in the two plantlets showed that MdWRKY40is and MdWRKY48 are potential regulators of cold tolerance.  When we overexpressed MdWRKY40is and MdWRKY48 in apple calli, the overexpression of MdWRKY48 had no significant effect on the callus, while MdWRKY40is overexpression promoted anthocyanin accumulation, increased callus cold tolerance, and promoted the expression of anthocyanin structural gene MdDFR and cold-signaling core gene MdCBF2.  Yeast one-hybrid screening and electrophoretic mobility shift assays showed that MdWRKY40is could only bind to the MdDFR promoter.  Yeast two-hybrid screening and bimolecular fluorescence complementation showed that MdWRKY40is interacts with the CBF2 inhibitor MdMYB15L through the leucine zipper (LZ).  When the LZ of MdWRMY40is was knocked out, MdWRKY40is overexpression in the callus did not affect MdCBF2 expression or callus cold tolerance, indicating that MdWRKY40is acts in the cold signaling pathway by interacting with MdMYB15L.  In summary, MdWRKY40is can directly bind to the MdDFR promoter in order to promote anthocyanin accumulation, and it can also interact with MdMYB15L to interfere with its inhibitory effect on MdCBF2, indirectly promoting MdCBF2 expression, and thereby improving cold tolerance.  These results provide a new perspective for the cold-resistance mechanism of apple rootstocks and a molecular basis for the screening of cold-resistant rootstocks.

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Molecular characterization of the SAUR gene family in sweet cherry and functional analysis of PavSAUR55 in the process of abscission HOU Qian-dong, HONG Yi, WEN Zhuang, SHANG Chun-qiong, LI Zheng-chun, CAI Xiao-wei, QIAO Guang, WEN Xiao-peng 2023, 22(6): 1720-1739.  DOI: 10.1016/j.jia.2023.04.031 Abstract ( )   PDF in ScienceDirect   Small auxin up RNA (SAUR) is a large gene family that is widely distributed among land plants.  In this study, a comprehensive analysis of the SAUR family was performed in sweet cherry, and the potential biological functions of PavSAUR55 were identified using the method of genetic transformation.  The sweet cherry genome encodes 86 SAUR members, the majority of which are intron-less.  These genes appear to be divided into seven subfamilies through evolution.  Gene duplication events indicate that fragment duplication and tandem duplication events occurred in the sweet cherry.  Most of the members mainly underwent purification selection pressure during evolution.  During fruit development, the expression levels of PavSAUR16/45/56/63 were up-regulated, and conversely, those of PavSAUR12/61 were down-regulated.  Due to the significantly differential expressions of PavSAUR13/16/55/61 during the fruitlet abscission process, they might be the candidate genes involved in the regulation of physiological fruit abscission in sweet cherry.  Overexpression of PavSAUR55 in Arabidopsis produced earlier reproductive growth, root elongation, and delayed petal abscission.  In addition, this gene did not cause any change in the germination time of seeds and was able to increase the number of lateral roots under abscisic acid (ABA) treatment.  The identified SAURs of sweet cherry play a crucial role in fruitlet abscission and will facilitate future insights into the mechanism underlying the heavy fruitlet abscission that can occur in this fruit crop.

Plant Protection

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Characterization of wheat monogenic lines with known Sr genes and wheat cultivars for resistance to three new races of Puccinia graminis f. sp. tritici in China WU Xian-xin, ZANG Chao-qun, ZHANG Ya-zhao, XU Yi-wei, WANG Shu, LI Tian-ya, GAO Li 2023, 22(6): 1740-1749.  DOI: 10.1016/j.jia.2022.08.125 Abstract ( )   PDF in ScienceDirect   Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a potentially devastating fungal disease of wheat worldwide.  The present study was to evaluate the resistance of 42 wheat monogenic lines with known stem rust resistance (Sr) genes and 69 wheat cultivars to three new Pgt races (34C0MRGQM, 34C3MKGQM, and 34C6MTGSM) identified from aeciospores at the seedling and adult-plant stages.  The phenotyping results revealed that monogenic lines harboring resistance genes Sr9e, Sr17, Sr21, Sr22, Sr26, Sr30, Sr31, Sr33, Sr35, Sr36, Sr37, Sr38, Sr47, SrTmp, and SrTt3 were effectively resistant to all three Pgt races at the seedling and adult-plant stages.  In contrast, monogenic lines containing Sr5, Sr6, Sr7b, Sr9a, Sr9d, Sr9f, Sr9g, Sr9b, Sr16, Sr24, Sr28, and Sr39 were highly susceptible to these races at both seedling and adult-plant stages.  The other lines with Sr8a, Sr10, Sr11, Sr13, Sr14, Sr15, Sr18, Sr20, Sr19, Sr23, Sr25, Sr27, Sr29, Sr32, and Sr34, displayed variable levels of resistance to one or two of the tested races.  Seedling infection types (ITs) and adult-plant infection responses (IRs) indicated that 41 (59.4%) of the wheat cultivars showed high resistance to all the three races.  Molecular marker analysis showed that four wheat culitvars likely carried Sr2, 20 wheat culitvars likely carried Sr31, 9 wheat culitvars likely carried Sr38, and none of the cultivars carried Sr24, Sr25, and Sr26.  Our results provide a scientific basis for rational utilization of the tested Sr genes and wheat cultivars against these novel Pgt races.

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Transcriptome analysis reveals different response of resistant and susceptible rice varieties to rice stripe virus infection LIU Yu, LIU Wen-wen, LI Li, Frederic FRANCIS, WANG Xi-feng 2023, 22(6): 1750-1762.  DOI: 10.1016/j.jia.2022.10.010 Abstract ( )   PDF in ScienceDirect   Rice stripe disease, caused by rice stripe virus (RSV) which is transmitted by small brown planthopper (SBPH, Laodelphax striatellus Fallen), resulted in serious losses to rice production during the last 2 decades.  Research on the molecular differences between resistant and susceptible rice varieties and the interaction between rice and RSV remains inadequate.  In this study, RNA-Seq was used to analyze the transcriptomic differences between the resistant and susceptible rice varieties at different times post RSV infection.  Through Gene Ontology (GO) annotation, the differentially expressed genes (DEGs) related to transcription factors, peroxidases, and kinases of 2 varieties at 3 time points were identified.  Comparing these 2 varieties, the DEGs associated with these 3 GOs were numerically less in the resistant variety than in the susceptible variety, but the expression showed a significant up- or down-regulation trend under the conditions of |log2(Fold change)|>0 & Padj<0.05 by significance analysis.  Then through Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation, DEGs involved in some pathways that have a contribution to disease resistance including plant hormone signal transduction and plant–pathogen interaction were found.  The results showed that resistance responses regulated by abscisic acid (ABA) and brassinosteroids (BR) were the same for 2 varieties, but that mediated by salicylic acid (SA) and jasmonic acid (JA)/ethylene (ET) were different.  The DEGs in resistant and susceptible varieties at the 3 time points were identified in both PAMP-triggered immunity (PTI) and Effector protein-triggered immunity (ETI), with that most of the unigenes of the susceptible variety were involved in PTI, whereas most of the unigenes of the resistant variety were involved in ETI.  These results revealed the different responses of resistant and susceptible varieties in the transcription level to RSV infection.

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Diagnosis and characterization of the ribosomal DNA-ITS of potato rot nematode (Ditylenchus destructor) populations from Chinese medicinal herbs NI Chun-hui, HAN Bian, LIU Yong-gang, Maria MUNAWAR, LIU Shi-ming, LI Wen-hao, SHI Ming-ming, LI Hui-xia, PENG De-liang 2023, 22(6): 1763-1781.  DOI: 10.1016/j.jia.2022.08.126 Abstract ( )   PDF in ScienceDirect   The potato rot nematode (Ditylenchus destructor) is a very economically important nematode in agronomic and horticultural plants worldwide.  In this study, 43 populations of D. destructor were collected from different hosts across China, including 37 populations from Chinese herbal medicine plants.  Obtained sequences of ITS-rDNA and D2–D3 of 28S-rDNA genes of D. destructor were compared and analyzed.  Nine types of significant length variations in ITS sequences were observed among all populations.  The differences in ITS1 length were mainly caused by the presence of repetitive elements with substantial base substitutions.  Reconstructions of ITS1 secondary structures showed that the minisatellites formed a stem structure.  Ten haplotypes were observed in all populations based on mutations and variations of helix H9.  Among them, 3 known haplotypes (A–C) were found in 7 populations isolated from potato, sweet potato, and Codonopsis pilosula, and 7 unique haplotypes were found in other 36 populations collected from C. pilosula and Angelica sinensis compared with 7 haplotypes (A–G) according to Subbotin’ system.  These unique haplotypes were different from haplotypes A–G, and we named them as haplotypes H–N.  The present results showed that a total of 14 haplotypes (A–N) of ITS-rDNA have been found in D. destructor.  Phylogenetic analyses of ITS-rDNA and D2–D3 showed that all populations of D. destructor were clustered into two major clades: one clade only containing haplotype A from sweet potato and the other containing haplotypes B–N from other plants.  For further verification, PCR-ITS-RFLP profiles were conducted on 7 new haplotypes.  Collectively, our study suggests that D. destructor populations on Chinese medicinal materials are very different from those on other hosts and this work provides a paradigm for relevant researches.

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Diurnal emission of herbivore-induced (Z)-3-hexenyl acetate and allo-ocimene activates sweet potato defense responses to sweet potato weevils XIAO Yang-yang, QIAN Jia-jia, HOU Xing-liang, ZENG Lan-ting, LIU Xu, MEI Guo-guo, LIAO Yin-yin 2023, 22(6): 1782-1796.  DOI: 10.1016/j.jia.2023.02.020 Abstract ( )   PDF in ScienceDirect   The sweet potato weevil (Cylas formicarius (Fab.) (Coleoptera: Brentidae)) is a pest that feeds on sweet potato (Ipomoea batatas (L.) Lam. (Solanales: Convolvulaceae)), causing substantial economic losses annually.  However, no safe and effective methods have been found to protect sweet potato from this pest.  Herbivore-induced plant volatiles (HIPVs) promote various defensive bioactivities, but their formation and the defense mechanisms in sweet potato have not been investigated.  To identify the defensive HIPVs in sweet potato, the release dynamics of volatiles was monitored.  The biosynthetic pathways and regulatory factors of the candidate HIPVs were revealed via stable isotope tracing and analyses at the transcriptional and metabolic levels.  Finally, the anti-insect activities and the defense mechanisms of the gaseous candidates were evaluated.  The production of (Z)-3-hexenyl acetate (z3HAC) and allo-ocimene was induced by sweet potato weevil feeding, with a distinct circadian rhythm.  Ipomoea batatas ocimene synthase (IbOS) is first reported here as a key gene in allo-ocimene synthesis.  Insect-induced wounding promoted the production of the substrate, (Z)-3-hexenol, and upregulated the expression of IbOS, which resulted in higher contents of z3HAC and allo-ocimene, respectively.  Gaseous z3HAC and allo-ocimene primed nearby plants to defend themselves against sweet potato weevils.  These results provide important data regarding the formation, regulation, and signal transduction mechanisms of defensive volatiles in sweet potato, with potential implications for improving sweet potato weevil management strategies.

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Model fitting of the seasonal population dynamics of the soybean aphid, Aphis glycines Matsumura, in the field XU Lei, ZHAO Tong-hua, Xing Xing, XU Guo-qing, XU Biao, ZHAO Ji-qiu 2023, 22(6): 1797-1808.  DOI: 10.1016/j.jia.2023.02.021 Abstract ( )   PDF in ScienceDirect   The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is one of the greatest threats to soybean production, and both trend analysis and periodic analysis of its population dynamics are important for integrated pest management (IPM).  Based on systematically investigating soybean aphid populations in the field from 2018 to 2020, this study adopted the inverse logistic model for the first time, and combined it with the classical logistic model to describe the changes in seasonal population abundance from colonization to extinction in the field.  Then, the increasing and decreasing phases of the population fluctuation were divided by calculating the inflection points of the models, which exhibited distinct seasonal trends of the soybean aphid populations in each year.  In addition, multifactor logistic models were then established for the first time, in which the abundance of soybean aphids in the field changed with time and relevant environmental conditions.  This model enabled the prediction of instantaneous aphid abundance at a given time based on relevant meteorological data.  Taken as a whole, the successful approaches implemented in this study could be used to build a theoretical framework for practical IPM strategies for controlling soybean aphids.

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Lack of fitness cost and inheritance of resistance to abamectin based on the establishment of a near-isogenic strain of Tetranychus urticae ZHANG Yan, TIAN Tian, ZHANG Kun, ZHANG You-jun, WU Qing-jun, XIE Wen, GUO Zhao-jiang, WANG Shao-li 2023, 22(6): 1809-1819.  DOI: 10.1016/j.jia.2022.10.012 Abstract ( )   PDF in ScienceDirect   Many populations of the two-spotted spider mite, Tetranychus urticae Koch, have developed high levels of resistance to the pesticide abamectin in China and other countries.  This study developed a near-isogenic line to understand better the inheritance, cross-resistance, and fitness costs associated with abamectin resistance in the field population of T. urticae in China.  We introduced the trait that confers extremely high abamectin resistance in a field-collected population of T. urticae into a susceptible laboratory strain (IPP-SS) to generate an abamectin-resistant near-isogenic line (NIL-Aba).  This process was carried out through multiple backcrossing to IPP-SS and via parthenogenesis and abamectin screening.  Compared with IPP-SS, the NIL-Aba strain had a 25 147-fold resistance to abamectin and a high level of cross-resistance to bifenthrin (288.17-fold), an intermediate level to emamectin benzoate (42.57-fold), and low levels to bifenazate, chlorfenapyr, cyflumetofen, cyenopyrafen, and cyetpyrafen with resistance ranging from 3.18- to 9.31-fold.  But it had no cross-resistance to profenofos.  The resistance to abamectin in NIL-Aba was autosomal, incompletely dominant, and polygenic.  Based on two sex life table parameters, no fitness cost was found in NIL-Aba.  Establishing the NIL-Aba strain provides a reliable basis for an in-depth study of abamectin resistance in T. urticae.  New information on toxicological characteristics and fitness cost should facilitate the management of abamectin resistance in field populations of T. urticae.

Animal Science · Veterinary Medicine

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Alternative polyadenylation events in epithelial cells sense endometritis progression in dairy cows Meagan J. STOTTS, Yangzi ZHANG, Shuwen ZHANG, Jennifer J. MICHAL, Juan VELEZ, Bothe HANS, Martin MAQUIVAR, Zhihua JIANG 2023, 22(6): 1820-1832.  DOI: 10.1016/j.jia.2022.11.009 Abstract ( )   PDF in ScienceDirect   Endometritis (inflammation of the endometrial lining) is one of the most devastating reproductive diseases in dairy cattle, resulting in substantial production loss and causing more than $650 million in lost revenue annually in the USA.  We hypothesize that alternative polyadenylation (APA) sites serve as decisive sensors for endometrium health and disease in dairy cows.  Endometrial cells collected from 18 cows with purulent vaginal discharge scored 0 to 2 were used for APA profiling with our whole transcriptome termini site sequencing (WTTS-seq) method.  Overall, pathogens trigger hosts to use more differentially expressed APA (DE-APA), more intronic DE-APA, more DE-APA sites per gene and more DE-genes associated with inflammation.  Host CD59 molecule (CD59), Fc fragment of IgG receptor IIa (FCGR2A), lymphocyte antigen 75 (LY75) and plasminogen (PLG) may serve as initial contacts or combats with pathogens on cell surface, followed by activation of nuclear receptor subfamily 1 group H member 4 (NR1H4) to regulate AXL receptor tyrosine kinase (AXL), FGR proto-oncogene, Src family tyrosine kinase (FGR), HCK proto-oncogene, Src family tyrosine kinase (HCK) and integrin subunit beta 2 (ITGB2) for anti-inflammation.  This study is the first to show significance of cilium pathways in endometrium health and animal reproduction.  MIR21 and MIR30A would be perfect antagonistic biomarkers for diagnosis of either inflammation or anti-inflammation.  These novel findings will set precedent for future genomic studies to aid the dairy industry develop new strategies to reduce endometritis incidence and improve fertility.

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Effect of dioscorea opposite waste on growth performance, blood parameters, rumen fermentation and rumen bacterial community in weaned lambs GUO Yun-xia, YANG Ruo-chen, DUAN Chun-hui, WANG Yong, HAO Qing-hong, JI Shou-kun, YAN Hui, ZHANG Ying-jie, LIU Yue-qin 2023, 22(6): 1833-1846.  DOI: 10.1016/j.jia.2022.10.002 Abstract ( )   PDF in ScienceDirect   This study investigated the effects of dioscorea opposite waste (DOW) on the growth performance, blood parameters, rumen fermentation and rumen microbiota of weaned lambs.  Sixty healthy weaned Small-Tailed Han lambs (male, (22.68±2.56) kg initially) were used as the experimental animals.  Four levels of concentrate: 0 (control, CON), 10% (DOW1), 15% (DOW2) and 20% (DOW3), were replaced with DOW in the basal diet as experimental treatments.  The results showed that lambs fed the DOW2 diet had a higher (P<0.05) dry matter intake (DMI) than the other groups.  There was no significant difference (P>0.05) among DOW groups in average daily weight gain (ADG), and replacing concentrate with DOW linearly or quadratically increased (P<0.05) the ADG, while lambs fed the DOW2 diet showed greater (P<0.05) ADG than the CON group.  The relative plasma concentration of growth hormone (GH), insulin like growth factor-1 (IGF-1) and insulin were affected by DOW, replacing concentrate with DOW linearly or quadratically (P<0.05) enhanced the plasma concentration of GH, IGF-1 and insulin, which was significantly higher (P<0.05) in the DOW2 group than in the CON, DOW1 and DOW3 groups.  In addition, the DOW treatment showed a lower (P<0.05) concentration of blood urea nitrogen (BUN) than the CON group.  Replacing concentrate with DOW quadratically decreased (P<0.05) the ruminal ammonia nitrogen (NH3-N) and increased (P<0.05) the total of volatile fatty acids (TVFAs) at 0 and 4 h after feeding as well as linearly decreased (P<0.05) the NH3-N at 8 h after feeding.  Replacing concentrate with DOW linearly decreased (P<0.05) the propionate and increased the aceate before feeding, and linearly decreased (P<0.05) propionate and quadratically increased (P<0.05) the aceate at 4 and 8 h after feeding.  Lambs fed the DOW2 diet increased the phylum Firmicutes and genera Succiniclasticum and Ruminococcus_1 groups, whereas decreased (P<0.05) the relative abundance of phylum Deferribacteres and genera intestinimonas and Ruminiclostridium.  In summary, replacing the concentrate with 15% DOW was beneficial for improving the rumen fermentation and ADG by increasing the DMI and modulating the rumen microbial community.

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Dietary aflatoxin B1 induces abnormal deposition of melanin in the corium layer of the chicken shank possibly via promoting the expression of melanin synthesis-related genes WANG Yong-li, HUANG Chao, YU Yang, CAI Ri-chun, SU Yong-chun, CHEN Zhi-wu, ZHENG Maiqing, CUI Huan-xian 2023, 22(6): 1847-1856.  DOI: 10.1016/j.jia.2023.04.001 Abstract ( )   PDF in ScienceDirect   San-Huang chicken is a high-quality breed in China with yellow feather, claw and break.  However, the abnormal phenomenon of the yellow shank turning into green shank of San-Huang chicken has been a concern, as it seriously reduces the carcass quality and economic benefit of yellow-feathered broilers.  In this study, the cause of this abnormal green skin in shank was systematically investigated.  Physiological anatomy revealed that the abnormal skin in shank was primarily due to the deposition of melanin under the dermis.  After analyzing multiple potential causes such as heredity (pedigree and genetic markers), environment (water quality monitoring) and feed composition (mycotoxin detection), excessive aflatoxin B1 (AFB1) in feed was screened, accompanied with a higher L-dihydroxy-phenylalanine (L-DOPA) (P<0.05) and melanin content (P<0.01).  So it was speculated that excessive AFB1 might be the main cause of abnormal green skin in shank.  Subsequently, the further results showed that a high concentration of AFB1 (>170 μg kg–1) indeed induced the abnormal green skin in shank compared to the normal AFB1 content (<10 μg kg–1), and the mRNA levels of TYR, TYRP1, MITE, MC1R and EDN3 genes related to melanin deposition would significantly up-regulate (P<0.01) and the content and activity of tyrosinase (TyR) significantly increased (P<0.05).  At the same time, the content of L-DOPA and melanin deposition also increased significantly (P<0.01), which also confirmed the effect of excessive AFB1 on melanin deposition in skin of shank.  Results of additional experiments revealed that the AFB1’s negative effect on melanin deposition in skin of shank could last for a longer time.  Taken together, the results of this study explained the occurrence and possible mechanisms of the abnormal AFB1-related green skin in shank of chickens.  Excessive AFB1 in diets increased the L-DOPA content and melanin abnormal deposition in the chicken shank possibly via promoting TyR content and activity, and the expression of melanin synthesis-related genes.  Furthermore, our findings once again raised the alarm of the danger of AFB1 in the broiler production.

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Insights into the effects of pulsed antimicrobials on the chicken resistome and microbiota from fecal metagenomes ZHAO Ruo-nan, CHEN Si-yuan, TONG Cui-hong, HAO Jie, LI Pei-si, XIE Long-fei, XIAO Dan-yu, ZENG Zhen-ling, XIONG Wen-guang 2023, 22(6): 1857-1869.  DOI: 10.1016/j.jia.2022.11.006 Abstract ( )   PDF in ScienceDirect   Antimicrobial resistance has become a global problem that poses great threats to human health.  Antimicrobials are widely used in broiler chicken production and consequently affect their gut microbiota and resistome.  To better understand how continuous antimicrobial use in farm animals alters their microbial ecology, we used a metagenomic approach to investigate the effects of pulsed antimicrobial administration on the bacterial community, antibiotic resistance genes (ARGs) and ARG bacterial hosts in the feces of broiler chickens.  Chickens received three 5-day courses of individual or combined antimicrobials, including amoxicillin, chlortetracycline and florfenicol.  The florfenicol administration significantly increased the abundance of mcr-1 gene accompanied by floR gene, while amoxicillin significantly increased the abundance of genes encoding the AcrAB-tolC multidrug efflux pump (marA, soxS, sdiA, rob, evgS and phoP).  These three antimicrobials all led to an increase in Proteobacteria.  The increase in ARG host, Escherichia, was mainly attributed to the β-lactam, chloramphenicol and tetracycline resistance genes harbored by Escherichia under the pulsed antimicrobial treatments.  These results indicated that pulsed antimicrobial administration with amoxicillin, chlortetracycline, florfenicol or their combinations significantly increased the abundance of Proteobacteria and enhanced the abundance of particular ARGs.  The ARG types were occupied by the multidrug resistance genes and had significant correlations with the total ARGs in the antimicrobial-treated groups.  The results of this study provide comprehensive insight into pulsed antimicrobial-mediated alteration of chicken fecal microbiota and resistome.

Agro-ecosystem & Environment

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Maize straw application as an interlayer improves organic carbon and total nitrogen concentrations in the soil profile: A four-year experiment in a saline soil CHANG Fang-di, WANG Xi-quan, SONG Jia-shen, ZHANG Hong-yuan, YU Ru, WANG Jing, LIU Jian, WANG Shang, JI Hong-jie, LI Yu-yi 2023, 22(6): 1870-1882.  DOI: 10.1016/j.jia.2023.02.025 Abstract ( )   PDF in ScienceDirect   Soil salinization is a critical environmental issue restricting agricultural production.  Deep return of straw to the soil as an interlayer (at 40 cm depth) has been a popular practice to alleviate salt stress.  However, the legacy effects of straw added as an interlayer at different rates on soil organic carbon (SOC) and total nitrogen (TN) in saline soils still remain inconclusive.  Therefore, a four-year (2015–2018) field experiment was conducted with four levels (i.e., 0, 6, 12 and 18 Mg ha–1) of straw returned as an interlayer.  Compared with no straw interlayer (CK), straw addition increased SOC concentration by 14–32 and 11–57% in the 20–40 and 40–60 cm soil layers, respectively.  The increases in soil TN concentration (8–22 and 6–34% in the 20–40 and 40–60 cm soil layers, respectively) were lower than that for SOC concentration, which led to increased soil C:N ratio in the 20–60 cm soil depth.  Increases in SOC and TN concentrations in the 20–60 cm soil layer with straw addition led to a decrease in stratification ratios (0–20 cm:20–60 cm), which promoted uniform distributions of SOC and TN in the soil profile.  Increases in SOC and TN concentrations were associated with soil salinity and moisture regulation and improved sunflower yield.  Generally, compared with other treatments, the application of 12 Mg ha–1 straw had higher SOC, TN and C:N ratio, and lower soil stratification ratio in the 2015–2017 period.  The results highlighted that legacy effects of straw application as an interlayer were maintained for at least four years, and demonstrated that deep soil straw application had a great potential for improving subsoil fertility in salt-affected soils.

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Significant reduction of ammonia emissions while increasing crop yields using the 4R nutrient stewardship in an intensive cropping system ZHANG Chong, WANG Dan-dan, ZHAO Yong-jian, XIAO Yu-lin, CHEN Huan-xuan, LIU He-pu, FENG Li-yuan, YU Chang-hao, JU Xiao-tang 2023, 22(6): 1883-1895.  DOI: 10.1016/j.jia.2022.12.008 Abstract ( )   PDF in ScienceDirect   Ammonia (NH3) emissions should be mitigated to improve environmental quality.  Croplands are one of the largest NH3 sources, they must be managed properly to reduce their emissions while achieving the target yields.  Herein, we report the NH3 emissions, crop yield and changes in soil fertility in a long-term trial with various fertilization regimes, to explore whether NH3 emissions can be significantly reduced using the 4R nutrient stewardship (4Rs), and its interaction with the organic amendments (i.e., manure and straw) in a wheat–maize rotation.  Implementing the 4Rs significantly reduced NH3 emissions to 6 kg N ha–1 yr–1 and the emission factor to 1.72%, without compromising grain yield (12.37 Mg ha–1 yr–1) and soil fertility (soil organic carbon of 7.58 g kg–1) compared to the conventional chemical N management.  When using the 4R plus manure, NH3 emissions (7 kg N ha–1 yr–1) and the emission factor (1.74%) were as low as 4Rs, and grain yield and soil organic carbon increased to 14.79 Mg ha–1 yr–1 and 10.09 g kg–1, respectively.  Partial manure substitution not only significantly reduced NH3 emissions but also increased crop yields and improved soil fertility, compared to conventional chemical N management.  Straw return exerted a minor effect on NH3 emissions.  These results highlight that 4R plus manure, which couples nitrogen and carbon management can help achieve both high yields and low environmental costs.

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Increasing nitrogen absorption and assimilation ability under mixed NO3– and NH4+ supply is a driver to promote growth of maize seedlings WANG Peng, WANG Cheng-dong, WANG Xiao-lin, WU Yuan-hua, ZHANG Yan, SUN Yan-guo, SHI Yi, MI Guo-hua 2023, 22(6): 1896-1908.  DOI: 10.1016/j.jia.2023.04.037 Abstract ( )   PDF in ScienceDirect   Compared with sole nitrate (NO3–) or sole ammonium (NH4+) supply, mixed nitrogen (N) supply may promote growth of maize seedlings.  Previous study suggested that mixed N supply not only increased photosynthesis rate, but also enhanced leaf growth by increasing auxin synthesis to build a large sink for C and N utilization.  However, whether this process depends on N absorption is unknown.  Here, maize seedlings were grown hydroponically with three N forms (NO3– only, 75/25 NO3–/NH4+ and NH4+ only).  The study results suggested that maize growth rate and N content of shoots under mixed N supply was little different to that under sole NO3– supply at 0–3 d, but was higher than under sole NO3– supply at 6–9 d.  15N influx rate under mixed N supply was greater than under sole NO3– or NH4+ supply at 6–9 d, although NO3– and NH4+ influx under mixed N supply were reduced compared to sole NO3– and NH4+ supply, respectively.  qRT-PCR determination suggested that the increased N absorption under mixed N supply may be related to the higher expression of NO3– transporters in roots, such as ZmNRT1.1A, ZmNRT1.1B, ZmNRT1.1C, ZmNRT1.2 and ZmNRT1.3, or NH4+ absorption transporters, such as ZmAMT1.1A, especially the latter.  Furthermore, plants had higher nitrate reductase (NR) glutamine synthase (GS) activity and amino acid content under mixed N supply than when under sole NO3– supply.  The experiments with inhibitors of NR reductase and GS synthase further confirmed that N assimilation ability under mixed N supply was necessary to promote maize growth, especially for the reduction of NO3– by NR reductase.  This research suggested that the increased processes of NO3– and NH4+ assimilation by improving N-absorption ability of roots under mixed N supply may be the main driving force to increase maize growth.

Agricultural Economics and Management

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Ensemble learning prediction of soybean yields in China based on meteorological data LI Qian-chuan, XU Shi-wei, ZHUANG Jia-yu, LIU Jia-jia, ZHOU Yi, ZHANG Ze-xi 2023, 22(6): 1909-1927.  DOI: 10.1016/j.jia.2023.02.011 Abstract ( )   PDF in ScienceDirect   The accurate prediction of soybean yield is of great significance for agricultural production, monitoring and early warning.  Although previous studies have used machine learning algorithms to predict soybean yield based on meteorological data, it is not clear how different models can be used to effectively separate soybean meteorological yield from soybean yield in various regions.  In addition, comprehensively integrating the advantages of various machine learning algorithms to improve the prediction accuracy through ensemble learning algorithms has not been studied in depth.  This study used and analyzed various daily meteorological data and soybean yield data from 173 county-level administrative regions and meteorological stations in two principal soybean planting areas in China (Northeast China and the Huang–Huai region), covering 34 years.  Three effective machine learning algorithms (K-nearest neighbor, random forest, and support vector regression) were adopted as the base-models to establish a high-precision and highly-reliable soybean meteorological yield prediction model based on the stacking ensemble learning framework.  The model’s generalizability was further improved through 5-fold cross-validation, and the model was optimized by principal component analysis and hyperparametric optimization.  The accuracy of the model was evaluated by using the five-year sliding prediction and four regression indicators of the 173 counties, which showed that the stacking model has higher accuracy and stronger robustness.  The 5-year sliding estimations of soybean yield based on the stacking model in 173 counties showed that the prediction effect can reflect the spatiotemporal distribution of soybean yield in detail, and the mean absolute percentage error (MAPE) was less than 5%.  The stacking prediction model of soybean meteorological yield provides a new approach for accurately predicting soybean yield.

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Uncertainty aversion and farmers’ innovative seed adoption: Evidence from a field experiment in rural China WU Hai-xia, SONG Yan, YU Le-shan, GE Yan 2023, 22(6): 1928-1944.  DOI: 10.1016/j.jia.2023.04.004 Abstract ( )   PDF in ScienceDirect   Based on the microdata of 705 wheat farmers in the Loess Plateau, this study empirically analyzes the impact of uncertainty on farmers’ adoption of innovative seeds using a field experiment.  The results indicate that farmers are generally ambiguity-averse and risk-averse.  In addition, farmers with higher ambiguity aversion and risk aversion are less likely to adopt innovative wheat seeds, where their risk aversion plays a dominant role.  Enhancing information access will alleviate the negative influence of ambiguity aversion on farmers’ adoption of innovative seeds, and interlinked insurance and credit contracts will be beneficial to ease the adverse effect of risk aversion on the adoption of innovative wheat seeds.  Meanwhile, heterogeneity analysis reveals that the inhibitory effects of ambiguity aversion and risk aversion on innovative seed adoption are more significant among farmers with lower education and household income.  The government can establish both ex-ante and ex-post relevant guarantee mechanisms to help farmers preferably cope with various uncertainties in the production process, remitting farmers’ ambiguity aversion and risk aversion to enhance new agricultural technology adoption rates.

Letter

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Identification of two novel linear epitopes on the p30 protein of African swine fever virus YU Si-hui, SHAN Zhao-meng, YANG Jing-jing, LIU Yi-ning, WU Chang-de, ZHANG Zhen-jiang, ZHU Yuan-mao, MENG Bo, ZHAN Jia-xing, WEN Xue-xia, ZHANG Ying 2023, 22(6): 1945-1949.  DOI: 10.1016/j.jia.2023.04.012 Abstract ( )   PDF in ScienceDirect