Archive

2021 Vol. 20 No. 1 Previous Issue    Next Issue

---

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


  Cover illustration


Download table of contents

×

Cover illustration


Animal infectious diseases cause huge economic losses to the livestock industry, which poses a serious threat to food safety. As one of the main sources of human epidemics, animal diseases also greatly affect human health. Disease-resistant breeding can significantly improve the resistance of animals to disease infection, and is one of the best solutions to the problem of animal infectious diseases and achieve “One Health Initiative”. Genome-editing technology can quickly improve the target traits, which provides an efficient new method for disease resistance breeding. Recently new research shows that pigs with precise editing of the two receptor genes (CD163 and pAPN) that mediate virus infection in pigs are completely resistant to the infection of porcine reproductive and respiratory syndrome virus (PRRSV) and transmissible gastroenteritis virus (TGEV), and exhibit decreased susceptibility to porcine deltacoronavirus (PDCoV). Using genome-editing method to breed disease-resistant pigs is like putting a mask on the pigs, which can effectively prevent virus infection. Long-term breeding and observation experiments, breeding experiments, and slaughter experiments of the National Breeding Testing Center have shown that the reproduction and production performance of double-gene-edited pigs are normal. These pigs will provide important materials for the breeding of new disease-resistant pig breeds. The research also demonstrates the great application value of emerging genome editing technology in animal breeding. The photo was taken by Mr. GE Changli, Shandong Landsee Genetics Co., Ltd., China. See pages 1–3 for more details.


---

For Selected:

Download Citations EndNote Ris BibTeX

Toggle Thumbnails

Commentary

Select

Infectious disease-resistant pigs: Will they fly? Tad S. SONSTEGARD, Perry B. HACKETT 2021, 20(1): 1-3.  DOI: 10.1016/S2095-3119(20)63468-2 Abstract ( )   PDF in ScienceDirect

Review

Select

Crop photosynthetic response to light quality and light intensity Iram SHAFIQ, Sajad HUSSAIN, Muhammad Ali RAZA, Nasir IQBAL, Muhammad Ahsan ASGHAR, Ali RAZA, FAN Yuan-fang, Maryam MUMTAZ, Muhammad SHOAIB, Muhammad ANSAR, Abdul MANAF, YANG Wen-yu, YANG Feng 2021, 20(1): 4-23.  DOI: 10.1016/S2095-3119(20)63227-0 Abstract ( )   PDF in ScienceDirect   Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity.  Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth.  The two components of light (light quality and light intensity) greatly affect plant photosynthesis and other plant’s morphological, physiological and biochemical parameters.  The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions.  To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development.  This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species (ROS) production, antioxidants, and hormone production.

Select

Alginate oligosaccharides preparation, biological activities and their application in livestock and poultry  LIU Ming, LIU Lei, ZHANG Hong-fu, YI Bao, Nadia EVERAERT 2021, 20(1): 24-34.  DOI: 10.1016/S2095-3119(20)63195-1 Abstract ( )   PDF in ScienceDirect   Alginate oligosaccharides (AOS), belonging to the class of functional marine oligosaccharides, are low-molecular polymers linked by β-1,4-mannuronic acid (M) and α-1,4-guluronic acid (G), which could be classically obtained by enzymatic hydrolysis of alginate. With low viscosity and good water solubility, as well as anti-oxidant, immune regulation, anti-bacterial and anti-inflammatory activities, AOS have been widely used in medical science and functional food, green agriculture and other fields. As new bio-feed additives, AOS have broad potential applications in animal husbandry. In this review, the sources of alginate, chemical structure and preparation methods of AOS, and their biological activities and application in livestock and poultry are summarized. We expect this review could contribute to lay a foundation of application and further research for AOS in livestock and poultry.

Crop Science

Select

Genome-wide pedigree analysis of elite rice Shuhui 527 reveals key regions for breeding REN Yun, CHEN Dan, LI Wen-jie, TAO Luo, YUAN Guo-qiang, CAO Ye, LI Xue-mei, DENG Qi-ming, WANG Shi-quan, ZHENG Ai-ping, ZHU Jun, LIU Huai-nian, WANG Ling-xia, LI Ping, LI Shuang-cheng 2021, 20(1): 35-45.  DOI: 10.1016/S2095-3119(20)63256-7 Abstract ( )   PDF in ScienceDirect   Hybrid rice significantly contributes to the food supply worldwide.  Backbone parents play important roles in elite hybrid rice breeding systems.  In this study, we performed pedigree-based analysis of the elite backbone parent rice variety, namely, Shuhui 527 (SH527, Oryza sativa), to exploit key genome regions during breeding.  Twenty-four cultivars (including SH527, its six progenitors and 17 derived cultivars) were collected and analyzed with high-density single nucleotide polymorphism (SNP) array.  Scanning all these cultivars with genome-wide SNP data indicated the unique contributions of progenitors to the SH527 genome and identified the key genomic regions of SH527 conserved within all its derivatives.  These findings were further supported by known rice yield-related genes or unknown QTLs identified by genome-wide association study.  This study reveals several key regions for SH527 and provides insights into hybrid rice breeding.

Select

TaSnRK2.4 is a vital regulator in control of thousand-kernel weight and response to abiotic stress in wheat MIAO Li-li, LI Yu-ying, ZHANG Hong-juan, ZHANG Hong-ji, LIU Xiu-lin, WANG Jing-yi, CHANG Xiao-ping, MAO Xin-guo, JING Rui-lian 2021, 20(1): 46-54.  DOI: 10.1016/S2095-3119(19)62830-3 Abstract ( )   PDF in ScienceDirect   Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) is a plant-specific serine/threonine kinase involved in response to adverse environmental stimuli.  Previous studies showed that TaSnRK2.4 was involved in response to abiotic stresses and conferred enhanced tolerance to multiple stresses in Arabidopsis.  Further experiments were performed to decipher the underlying mechanisms and discover new functions.  The genomic sequences of TaSnRK2.4s locating on chromosome 3A, 3B and 3D were obtained.  Sequencing identified one and 13 variations of TaSnRK2.4-3A and TaSnRK2.4-3B, respectively, but no variation was detected in TaSnRK2.4-3D.  The markers 2.4AM1, 2.4BM1 and 2.4BM2 were developed based on three variations.  Association analysis showed that both TaSnRK2.4-3A and TaSnRK2.4-3B were significantly associated with thousand-kernel weight (TKW), and that SNP3A-T and SNP3B-C were favorable alleles for higher TKW.  Yeast two-hybrid and split luciferase assays showed that TaSnRK2.4 physically interacted with abiotic stress responsive protein TaLTP3, suggesting that TaSnRK2.4 enhanced abiotic stress tolerance by activating TaLTP3.  Our studies suggested that TaSnRK2.4 have potential in improving TKW and response to abiotic stress.

Select

Development and characterization of new allohexaploid resistant to web blotch in peanut WANG Si-yu, LI Li-na, FU Liu-yang, LIU Hua, QIN Li, CUI Cai-hong, MIAO Li-juan, ZHANG Zhong-xin, GAO Wei, DONG Wen-zhao, HUANG Bing-yan, ZHENG Zheng, TANG Feng-shou, ZHANG Xin-you, DU Pei 2021, 20(1): 55-64.  DOI: 10.1016/S2095-3119(20)63228-2 Abstract ( )   PDF in ScienceDirect   Peanut diseases seriously threaten peanut production, creating disease-resistant materials via interspecific hybridization is an effective way to deal with this problem.  In this study, the embryo of an interspecific F1 hybrid was obtained by crossing the Silihong (Slh) cultivar with Arachis duranensis (ZW55), a diploid wild species.  Seedlings were generated by embryo rescue and tissue culture.  A true interspecific hybrid was then confirmed by cytological methods and molecular markers.  After treating seedlings with colchicine during in vitro multiplication, the established interspecific F1 hybrid produced seeds which were named as Am1210.  With oligonucleotide fluorescence in situ hybridization (Oligo FISH), molecular marker evaluations, morphological and web blotch resistance characterization, we found that: 1) Am1210 was an allohexaploid between Slh and ZW55; 2) the traits of spreading lateral branches, single-seeded or double-seeded pods and red seed coats were observed to be dominant compared to the erect type, multiple-seeded pods and brown seed coats; 3) the web blotch resistance of Am1210 was significantly improved than that of Slh, indicating the contribution of the web blotch resistance from the wild parent A. duranensis.  In addition, 69 dominant and co-dominant molecular markers were developed which could be both used to verify the hybrid in this study and to identify translocation or introgression lines with A. duranensis chromosome fragments in future studies as well.

Select

Compact plant type rice has higher lodging and N resistance under machine transplanting DING Chao, LUO Xi-kun, WU Qiong, LU Bo, DING Yan-feng, WANG Shao-hua, LI Gang-hua 2021, 20(1): 65-77.  DOI: 10.1016/S2095-3119(20)63229-4 Abstract ( )   PDF in ScienceDirect   To identify the major factors that contribute to the difference in lodging among different rice varieties under machine transplanting and their responses to nitrogen (N), field experiments were conducted at Danyang County (a representative eco-site of the Lower Yangtze River) in Jiangsu Province, China in 2017 and 2018, 22 hybrid indica varieties (HIs), 22 inbred japonica varieties (IJs) and two indica japonica hybrid varieties (IJHs) were transplanted by machine with three N rates (N0, N150 and N300, 0, 150 and 300 kg ha–1, respectively).  Lodging-related physical parameters, morphological characteristics and apparent transport rates of dry matter were examined.  Significant difference in yield was observed among different types of rice, and followed by IJs<HIs<IJHs.  The average lodging index (LI) of hybrid varieties (HIs and IJHs) was higher than that of the inbred varieties (IJs) with higher plant height; moreover, lower apparent export rate of dry matter resulted lower LI in IJHs than in HIs.  The HIs had a large difference in the LI, which came from the difference in bending stress (BS) induced by the difference in the apparent export rate of dry matter, varieties with lower leaf angle of upper three leaves possess strong lodging resistance capacity; however, the gap among the IJs was due to the difference in the cross section modulus (Z).  The LI in the IJs or IJHs increased slightly with the increased N application, and there was no lodging incidence under the high N level, which was due to the low leaf angle and barely changed under high N; there was a significant interaction between varieties (HIs) and N rates in lodging rate and LI, varieties with lower leaf angle of upper three leaves were resistant to high N.  These results suggest that compact plant type rice has higher lodging and N resistance at machine-transplanting method.

Select

N, P and K use efficiency and maize yield responses to fertilization modes and densities LI Guang-hao, CHENG Qian, LI Long, LU Da-lei, LU Wei-ping 2021, 20(1): 78-86.  DOI: 10.1016/S2095-3119(20)63214-2 Abstract ( )   PDF in ScienceDirect   Optimal planting density and proper fertilization method are important factors to improve maize yield and nutrient utilization.  A two-year (2016 and 2017) field experiment was conducted with three plant densities (6.0, 7.5 and 9.0 plants m−2) and three fertilization modes (no fertilizer, 0F; one-off application of slow-released fertilizer, SF; twice application of conventional fertilizer, CF).  Results indicated that the grain yields and N, P and K use efficiencies under SF with the optimal planting density (7.5 plants m−2) were the highest among all the treatments in 2016 and 2017.  Compared with CF, SF could increase post-silking dry matter accumulation and promote N, P and K uptake at pre- and post-silking stages; this treatment increased grain N, P and K concentrations and resulted in high N, P and K use efficiencies.  Nutrient (N, P and K) absorption efficiencies and partial productivity, and nutrient (N and P) recovery efficiency in SF treatment were significantly higher than those in CF treatments under the planting density of 7.5 plants m−2.  Under both SF and CF conditions, the grain yield, total N accumulation and nutrient use efficiencies initially increased, peaked at planting density of 7.5 plants m−2, and then decreased with increasing plant density.  Based on the yield and nutrient use efficiency in two years, plant density of 7.5 plants m−2 with SF can improve both the grain yield and N, P and K use efficiency of spring maize in Jiangsu Province, China.

Select

Efficiency of seed bio-priming technique for healthy mungbean productivity under terminal drought stress Hamid NAWAZ, Nazim HUSSAIN, Niaz AHMED, Haseeb-ur-REHMAN, Javaiz ALAM 2021, 20(1): 87-99.  DOI: 10.1016/S2095-3119(20)63184-7 Abstract ( )   PDF in ScienceDirect   Recently, drought-induced damaging impact in reducing the crop growth and development is drastically ranked at the top under various abiotic stresses.  And especially water stress at the reproductive growth stages termed as terminal drought has become a severe threat for mungbean productivity.  To mitigate the drought stress condition, “bio-priming” has emerged as a newly agronomic and sustainable technique in improving the mungbean production.  A 2-year field study during Kharif season 2017–2018 was conducted to investigate the efficacy of rhizobacteria seed priming in mungbean (AZRI mung-06), at Agronomic Research Area, Department of Agronomy, Bahauddin Zakariya University, Multan, Pakistan.  The experiment comprised two factors containing FA (seed treatments, control (dry seeds), hydro-priming, silicon (Si)-priming, and bio-priming (mixture strains of Pseudomonas fluorescens+Rhizobium phaseoli)) and FB (irrigation water-regimes at various growth stages including leaf formation (L), stem elongation (S)+flowering (F)+pod formation (P) containing treatments are normal irrigation (IL+S+F+P) and terminal drought stress (IF+P)).  All the treatments were arranged in randomized complete block design under factorial design and were replicated thrice.  Results indicated that the exposure of drought stress at flowering and pod formation stages hampered the morpho-physiological growth and yield of mungbean.  Nevertheless, seed priming treatments particularly bio-priming were effective in alleviating the detrimental effects of drought stress.  Bio-priming significantly increased the yield and yield components (seeds/plant, 1 000-grain weight and harvest index) of mungbean and regulated the activities/levels of antioxidants (superoxide dismutase, catalase, peroxidase, ascorbic acid, and total phenolics) under drought stress.  Compared with the control, bio-priming increased the seed yield of mungbean by 8–12% under normal as well as drought stress conditions during both years of study.  Bio-priming also improved the nutrient uptake behavior followed by Si- and hydro-priming treatments under terminal drought stress.  The study emphasized the effectiveness of bio-priming as dual seed treatment method may be helpful for vigorous germination of mungbean production along with plant tolerance against terminal drought stress.  Among the various treatments, plants treated with bio-priming technique compensated the grain yield due to having strong antioxidant defense system and better nutrient uptake behaviour under terminal drought stress.  Economic analysis also concluded that bio-priming is the easiest, cost-effective, friendly, and sustainable approach for the maximization of the mungbean production.

Select

Reduced square Bacillus thuringiensis insecticidal protein content of transgenic cotton under N deficit CHEN Yuan, LIU Zhen-yu, Leila I. M. TAMBEL, ZHANG Xiang, CHEN Yuan, CHEN De-hua 2021, 20(1): 100-108.  DOI: 10.1016/S2095-3119(20)63190-2 Abstract ( )   PDF in ScienceDirect   To clarify the effect of the N deficit on the amount of square Bt insecticidal protein, different N application rates (0, 75, 150, 225, and 300 kg ha–1) were imposed on the conventional cultivar Sikang 1 (SK-1) and hybrid cultivar Sikang 3 (SK-3) during 2015–2016 cotton growth seasons.  Under different N application rates, the square number per plant, square volume and square dry weight reduced when the N rates decreased from conventional rate (300 kg ha–1) to 0 kg ha–1.  And the square Bt protein content decreased accordingly.  The analysis of N metabolism showed that soluble protein content, GPT and GOT activities decreased, free amino acid, peptidase and protease activities increased under N deficit.  Correlation analysis indicated that the reduced Bt protein content under N deficit was related to altered N metabolism.  In conclusion, square development and the amount of square Bt toxin both decreased under N deficit, indicating that promoting the square development under appropriate N application rate would also promote the insect resistance during squaring stage.

Select

Metabolic responses to combined water deficit and salt stress in maize primary roots LI Peng-cheng, YANG Xiao-yi, WANG Hou-miao, PAN Ting, YANG Ji-yuan, WANG Yun-yun, XU Yang, YANG Ze-feng, XU Chen-wu 2021, 20(1): 109-119.  DOI: 10.1016/S2095-3119(20)63242-7 Abstract ( )   PDF in ScienceDirect   Soil water deficit and salt stress are major limiting factors of plant growth and agricultural productivity.  The primary root is the first organ to perceive the stress signals for drought and salt stress.  In this study, maize plant subjected to drought, salt and combined stresses displayed a significantly reduced primary root length relative to the control plants.  GC-MS was used to determine changes in the metabolites of the primary root of maize in response to salt, drought and combined stresses.  A total of 86 metabolites were measured, including 29 amino acids and amines, 21 organic acids, four fatty acids, six phosphoric acids, 10 sugars, 10 polyols, and six others.  Among these, 53 metabolites with a significant change under different stresses were identified in the primary root, and the content of most metabolites showed down-accumulation.  A total of four and 18 metabolites showed significant up- and down-accumulation to all three treatments, respectively.  The levels of several compatible solutes, including sugars and polyols, were increased to help maintain the osmotic balance.  The levels of metabolites involved in the TCA cycle, including citric acid, ketoglutaric acid, fumaric acid, and malic acid, were reduced in the primary root.  The contents of metabolites in the shikimate pathway, such as quinic acid and shikimic acid, were significantly decreased.  This study reveals the complex metabolic responses of the primary root to combined drought and salt stresses and extends our understanding of the mechanisms involved in root responses to abiotic tolerance in maize.

Horticulture

Select

Genome-wide identification and expression profiling of MYB transcription factor genes in radish (Raphanus sativus L.) Everlyne M’mbone MULEKE, WANG Yan, ZHANG Wan-ting, XU Liang, YING Jia-li, Bernard K. KARANJA, ZHU Xian-wen, FAN Lian-xue, Zarwali AHMADZAI, LIU Li-wang 2021, 20(1): 120-131.  DOI: 10.1016/S2095-3119(20)63308-1 Abstract ( )   PDF in ScienceDirect   Radish (Raphanus sativus L.), an important root vegetable crop of the Brassicaceae family, has a high level of anthocyanin accumulation in its pigment root tissues.  It was reported that MYB transcription factors (TFs) play vital roles in plant development and anthocyanin metabolism, and the PAP1/2 could promote expression of anthocyanin biosynthesis genes.  In this study, a total of 187 radish MYB genes (RsMYBs) were identified in the radish genome and clustered into 32 subfamilies.  Among them, 159 RsMYBs were localized on nine radish chromosomes.  Interestingly, 14 RsMYBs exhibited differential expression profiles in different taproot developmental stages among four differently colored radish lines.  A number of RsMYBs were highly expressed in the pigmented root tissues at the maturity stage, several genes including RsMYB41, RsMYB117, and RsMYB132 being homologous to PAP1/2, showed high expression levels in the red skin of NAU-YH (red skin-white flesh) taproot, while RsMYB65 and RsMYB159 were highly expressed in the purple root skin of NAU-YZH (purple skin-red flesh), indicating that these RsMYBs might positively regulate the process of anthocyanin accumulation in radish taproot.  These results would provide valuable information for further functional characterization of RsMYBs, and facilitate clarifying the molecular mechanism underlying anthocyanin biosynthesis in radish.

Select

Integrative analysis of the metabolome and transcriptome reveals seed germination mechanism in Punica granatum L. FU Fang-fang, PENG Ying-shu, WANG Gui-bin, Yousry A. EL-KASSABY, CAO Fu-liang 2021, 20(1): 132-146.  DOI: 10.1016/S2095-3119(20)63399-8 Abstract ( )   PDF in ScienceDirect   We conducted an integrative system biology of metabolome and transcriptome profile analyses during pomegranate (Punica granatum L.) seed germination and utilized a weighted gene co-expression network analysis (WGCNA) to describe the functionality and complexity of the physiological and morphogenetic processes as well as gene expression and metabolic differences during seed germination stages.  In total, 489 metabolites were detected, including 40 differentially accumulated metabolites.  The transcriptomic analysis showed the expression of 6 984 genes changed significantly throughout the whole germination process.  Using WGCNA, we identified modules related to the various seed germination stages and hub genes.  In the initial imbibition stage (stage 1), the pivotal genes involved in RNA transduction and the glycolytic pathway were most active, while in the sprouting stage (stage 4), the pivotal genes were involved in multiple metabolic pathways.  In terms of secondary metabolic pathways, we found flavonoid 4-reductase genes of anthocyanin biosynthesis pathway are most significantly affected during pomegranate seed germination, while the flavonol synthase gene was mainly involved in the regulation of isoflavonoid biosynthesis.

Plant Protection

Select

StKU80, a component in the NHEJ repair pathway, is involved in mycelial morphogenesis, conidiation, appressorium development, and oxidative stress reactions in Exserohilum turcicum GONG Xiao-dong, LIU Yu-wei, BI Huan-huan, YANG Xiao-rong, HAN Jian-min, DONG Jin-gao, GU Shou-qin 2021, 20(1): 147-158.  DOI: 10.1016/S2095-3119(20)63233-6 Abstract ( )   PDF in ScienceDirect   Homologous recombination (HR) and nonhomologous end joining (NHEJ) are considered the two main double-strand break (DSB) repair approaches in eukaryotes.  Inhibiting the activities of the key component in NHEJ commonly enhances the efficiency of targeted gene knockouts or affects growth and development in higher eukaryotes.  However, little is known about the roles of the NHEJ pathway in foliar pathogens.  Here we identified a gene designated StKU80, which encodes a putative DNA end-binding protein homologous to yeast Ku80, in the foliar pathogen Exserohilum turcicum.  Conserved domain analysis showed that the typical domains VWA, Ku78 and Ku-PK-bind are usually present in Ku70/80 proteins in eukaryotes and are also present in StKu80.  Phylogenetic analysis indicated that StKu80 is most closely related to Ku80 (XP_001802136.1) from Parastagonospora nodorum, followed by Ku80 (AGF90044.1) from Monascus ruber.  Furthermore, the gene knockout mutants ΔStKU80-1 and ΔStKU80-2 were obtained.  These mutants displayed longer septas, thinner cell walls, smaller amounts of substances on cell wall surfaces, and more mitochondria per cell than the wild-type (WT) strain but similar HT-toxin activity.  The mutants did not produce conidia and mature appressoria.  On the other hand, the mutants were highly sensitive to H2O2, but not to ultraviolet radiation.  In summary, the StKU80 plays devious roles in regulating the development of E.?turcicum.

Select

In-vitro assessment for the control of Fusarium species using a lactic acid bacterium isolated from yellow pitahaya (Selenicereus megalanthus (K. Schum. Ex Vaupel Moran)) Leidy J. VALENCIA-HERNÁNDEZ, Karina LÓPEZ-LÓPEZ, Eyder D. GÓMEZ-LÓPEZ, Liliana SERNA-COCK, Cristobal N. AGUILAR 2021, 20(1): 159-167.  DOI: 10.1016/S2095-3119(20)63284-1 Abstract ( )   PDF in ScienceDirect   The fungistatic activity of a lactic acid bacterium, which had been isolated from yellow pitahaya cultures, against fungi associated with basal rot (Fusarium oxysporum and Fusarium fujikuroi) was measured in the present study.  Its activity was assessed in three fractions: fermented (S1), metabolic products (S2), and biomass (S3), using two fermentation substrates: Man Rogosa Sharpe agar (MRS) and potato dextrose agar (PDA).  The bacterium was molecularly identified as Lactobacillus plantarum.  S3 reduced F. fujikuroi growth by 100% over 48 h of fermentation, which occurred during the stationary phase of bacterial growth.  The three fractions’ fungistatic activity against F. fujikuroi depended on the substrate employed.  The fermentation kinetic parameters for L. plantarum indicated that its specific growth rate was 0.46 h–1, with 93.63% substrate consumption, 0.045 kg kg–1 cell yield, and 0.54 kg kg–1 product yield.  The kinetic parameters calculated will allow for bacteria production scaling.  These in-vitro trials reveal L. plantarum’s possible application as a biocontrol agent for diseases associated with Fusarium.  However, further ex-vivo and in-vivo researches are required to demonstrate its behavior in crops.

Select

Identification and resistant characterization of legumes sources against Meloidogyne incognita #br# Pornthip RUANPANUN, Prakit SOMTA 2021, 20(1): 168-177.  DOI: 10.1016/S2095-3119(20)63414-1 Abstract ( )   PDF in ScienceDirect   Root-knot nematodes (RKNs; Meloidogyne spp.) are becoming a serious problem in legume production.  This study identified Vigna genotypes exhibiting resistance to M. incognita (RKN) and characterized the modes of the resistance to M. incognita.  In total, 279 accessions from 21 Vigna species were screened for resistance based on a galling index (GI) and an egg mass index (EI).  Seven accessions were highly resistant to RKN with GI≤25, namely JP74716 (V. mungo var. mungo; cultivated black gram), JP107881 (V. nepalensis), JP229392 (V. radiata var. sublobata; wild mungbean), AusTRCF118141 (V. unguiculata subsp. unguiculata; cultivated cowpea), AusTRCF306385 (V. unguiculata subsp. unguiculata), AusTRCF322090 (V. vexillata var. vexillata; wild zombi pea) and JP235929 (V. vexillata var. vexillata).  JP229392 and AusTRCF322090 were the most resistant accessions having EI values of 18.74 and 1.88, respectively.  Continuous culture of M. incognita on both JP229392 and AusTRCF322090 resulted in a weakness in pathogenic ability for this RKN.  The resistance in JP229392 and AusTRCF322090 to RKN appeared to be antibiosis that was associated with reduced nematode penetration, retardation of nematode development and impeding giant cell formation.  The Vigna germplasm resistance to RKN identified in this study could be utilized as gene sources for the development of RKN-resistant Vigna cultivars.

Select

Performance and transcriptomic response of the English grain aphid, Sitobion avenae, feeding on resistant and susceptible wheat cultivars LAN Hao, ZHANG Zhan-feng, WU Jun, CAO He-he, LIU Tong-xian 2021, 20(1): 178-190.  DOI: 10.1016/S2095-3119(20)63349-4 Abstract ( )   PDF in ScienceDirect   Plant resistance against insects mainly depends on nutrient restriction and toxic metabolites, but the relative importance of nutrition and toxins remains elusive.  We examined performance, nutrition ingestion, and transcriptome response of the English grain aphid, Sitobion avenae, feeding on resistant Xiaoyan 22 (XY22) and susceptible Xinong 979 (XN979) wheat cultivars.  Aphids had lower body weight and fecundity when feeding on XY22 than on XN979, although the phloem sap of XY22 had a higher nutritive quality (in terms of amino acid:sucrose ratio).  Aphids feeding on XY22 also had a lower honeydew excretion rate than those on XN979, suggesting that aphids ingested less phloem sap from XY22.  The transcriptome data showed 600 differentially expressed genes (DEGs), and 11 of the top 20 KEGG pathways significantly enriched in DEGs were involved in nutrient metabolism.  We found 81 DEGs associated with the metabolism of sugars, lipids, and amino acids, 59 of which were significantly downregulated in aphids feeding on XY22.  In contrast, there were 18 DEGs related to detoxifying metabolism, namely eight UDP-glucuronosyltransferases, six cytochromes P450 monooxygenases, one glutathione S-transferase, two ATP-binding cassette transporters, and one major facilitator superfamily transporter; 12 of these were upregulated in the aphids feeding on XY22.  Our results indicated that both the quantity and quality of phloem nutrition available to aphids are critical for the growth and development of aphids, and the higher resistance of XY22 is mainly due to the reduction in phloem sap ingested by aphids, rather than toxic metabolites.

Select

InvasionDB: A genome and gene database of invasive alien species HUANG Cong, LANG Kun, QIAN Wan-qiang, WANG Shu-ping, CAO Xiao-mei, HE Rui, ZHAN An-ran, CHEN Meng-yao, YANG Nian-wan, LI Fei 2021, 20(1): 191-200.  DOI: 10.1016/S2095-3119(20)63231-2 Abstract ( )   PDF in ScienceDirect   Invasive alien species (IAS) are species whose introduction to areas outside of their native range cause harm to economics, biodiversity, and the environment.  Understanding the genetic basis of invasiveness is critical for preventing invasion by an alien species and managing IAS with eco-friendly control methods.  In addition, uncovering the genomic features of IAS is essential for accurately predicting invasiveness.  However, even though increasing efforts have been devoted to sequencing the genomes of IAS, there is still not an integrated genome database for the invasive biology community.  Here, we first determined a list of invasive plants and animals by mining references and databases.  Then, we retrieved the genomic and gene data of these IAS, and constructed a database, InvasionDB.  InvasionDB encompasses 131 IAS genomes, 76 annotated IAS assemblies, and links these data to conventional functions such as searching for gene coding sequences and Pfam, KEGG, NR annotations, BLAST server, JBrowse, and downloads services.  Next, we analyzed 19 invasiveness-related gene families which confer invasiveness in insects.  To study the roles of noncoding RNA in invasiveness, we also annotated 135 494 miRNAs, 89 294 rRNAs, and 2 671 941 tRNAs from these IAS.  In summary, InvasionDB is useful for studying the invasiveness at the genomic level, and thus helps to develop novel management strategies to control IAS.

Animal Science · Veterinary Medicine

Select

Identification and functional prediction of long intergenic noncoding RNAs in fetal porcine longissimus dorsi muscle LI Cen-cen, YU Shu-long, REN Hai-feng, WU Wei, WANG Ya-ling, HAN Qiu, XU Hai-xia, XU Yong-jie, ZHANG Peng-peng 2021, 20(1): 201-211.  DOI: 10.1016/S2095-3119(20)63261-0 Abstract ( )   PDF in ScienceDirect   Pigs are globally farmed animals which provide protein for human consumption in the form of skeletal muscle.  To better understand the function of long intergenic noncoding RNAs (lincRNAs) in porcine skeletal muscle growth and development, we collected RNA-seq data from porcine longissimus dorsi muscle (LDM) during embryonic development.  We identified a total of 739 lincRNA transcripts, which were distributed on all chromosomes except the chromosome Y, and analyzed their molecular characteristics.  Compared to protein-coding genes, lincRNAs showed shorter transcripts, longer exons, fewer exons and higher tissue specificity.  In addition, the abundance of lincRNAs in five embryonic development stages were analyzed and 45 differentially expressed lincRNAs were screened, three of which were highly expressed in LDM during porcine embryonic development.  Finally, we predicted the potential target genes and functions of the lincRNAs, and identified 1 537 cis-target genes and 8 571 trans-target genes.  Furthermore, we identified two key candidate lincRNAs involved in muscle development, XLOC_024652 and XLOC_001832, for post-trial validation.  Our results provide a genome-wide resource of lincRNAs which are potentially involved in porcine embryonic skeletal muscle development and lay a foundation for the further study of their functions.

Select

Switches in transcriptome functions during seven skeletal muscle development stages from fetus to kid in Capra hircus LING Ying-hui, ZHENG Qi, JING Jing, SUI Meng-hua, ZHU Lu, LI Yun-sheng, ZHANG Yun-hai, LIU Ya, FANG Fu-gui, ZHANG Xiao-rong 2021, 20(1): 212-226.  DOI: 10.1016/S2095-3119(20)63268-3 Abstract ( )   PDF in ScienceDirect   Skeletal muscle accounts for about 40% of mammalian body weight, the development of which is a dynamic, complex and precisely regulated process that is critical for meat production. We here described the transcriptome expression profile in 21 goat samples collected at 7 growth stages from fetus to kid, including fetal 45 (F45), 65 (F65), 90 (F90), 120 (F120), and 135 (F135) days, and birth 1 (B1) day and 90 (B90) days kids.  Paraffin sections combined with RNA-seq data of the 7 stages divided the transcriptomic functions of skeletal muscle into 4 states: before F90, F120, F135 and B1, and B90.  And the dynamic expression of all 4 793 differentially expressed genes (DEGs) was identified.  Furthermore, DEGs were clustered by weighted gene correlation network analysis into 4 modules (turquoise, grey, blue and brown) that corresponded to these 4 states.  Functional and pathway analysis indicated that the active genes in the stages before F90 (turquoise) were closely related to skeletal muscle proliferation.  The DEGs in the F120-related module (grey) were found to participate in the regulation of skeletal muscle structure and skeletal muscle development by regulating tRNA.  The brown module (F135 and B1) regulated fatty acid biological processes to maintain the normal development of muscle cells.  The DEGs of B90 high correlation module (blue) were involved the strengthening and power of skeletal muscle through the regulation of actin filaments and tropomyosin.  Our current data thus revealed the internal functional conversion of the goat skeletal muscle in the growth from fetus to kid.  The results provided a theoretical basis for analyzing the involvement of mRNA in skeletal muscle development.

Select

Effects of selenium source and level on growth performance, antioxidative ability and meat quality of broilers WANG Chuan-long, XING Guan-zhong, WANG Li-sai, LI Su-fen, ZHANG Li-yang, LU Lin, LUO Xu-gang, LIAO Xiu-dong 2021, 20(1): 227-235.  DOI: 10.1016/S2095-3119(20)63432-3 Abstract ( )   PDF in ScienceDirect   This experiment was conducted to investigate the effects of selenium (Se) source and level on growth performance, carcass traits, antioxidative ability and meat quality of broilers.  A total of 320 one-d-old Arbor Acres commercial broilers were randomly assigned to 1 of 5 treatments with 8 replicates in a completely randomized design involving a 2×2 factorial arrangement of treatments plus one Se-unsupplemented basal diet control for 42 d.  The two Se sources were sodium selenite and Se yeast, and the two supplemental Se levels were 0.20 and 0.40 mg Se kg–1.  The results showed that broilers fed the Se-supplemented diets had higher (P<0.05) average daily gain and average daily feed intake from 22 to 42 d of age, eviscerated yield and abdominal fat percentages, Se concentrations and glutathione peroxidase (GSH-Px) activities in breast and thigh muscles on d 42, and lower (P<0.05) feed/gain from 1 to 21 and 22 to 42 d of age, mortality from 22 to 42 d of age and malondialdehyde (MDA) concentration in thigh muscle on d 42 than those fed the control diet.  Broilers fed the diets supplemented with Se yeast had higher (P<0.05) pH value and lower (P<0.05) shear force in thigh muscle than those fed the diets supplemented with sodium selenite.  Additionally, broilers fed the diets supplemented with 0.40 mg Se kg–1 had lower (P<0.05) shear force in thigh muscle and higher (P<0.05) GSH-Px activities in breast and thigh muscles than those fed the diets supplemented with 0.20 mg Se kg–1.  Furthermore, broilers fed the diet supplemented with Se yeast at 0.40 mg Se kg–1 had higher (P<0.05) Se concentrations in breast and thigh muscles than those fed the diet supplemented with Se yeast at 0.20 mg Se kg–1, but no differences (P<0.05) were observed in these indices of broilers fed the diets supplemented with sodium selenite between 0.20 and 0.40 mg Se kg–1.  The results from the present study indicated that supplemental Se could increase the growth performance, muscle Se concentration and antioxidative ability of broilers; and the Se from Se yeast was more effective than the Se from sodium selenite in improving meat quality of broilers.

Agro-ecosystem & Environment

Select

Effects of long-term straw return on soil organic carbon fractions and enzyme activities in a double-cropped rice paddy in South China HUANG Wan, WU Jian-fu, PAN Xiao-hua, TAN Xue-ming, ZENG Yong-jun, SHI Qing-hua, LIU Tao-ju, ZENG Yan-hua 2021, 20(1): 236-247.  DOI: 10.1016/S2095-3119(20)63347-0 Abstract ( )   PDF in ScienceDirect   Long-term straw return is an important carbon source for improving soil organic carbon (SOC) stocks in croplands, and straw removal through burning is also a common practice in open fields in South China.  However, the specific effects of long-term rice straw management on SOC fractions, the related enzyme activities and their relationships, and whether these effects differ between crop growing seasons remain unknown.  Three treatments with equal nitrogen, phosphorus, and potassium nutrient inputs, including straw/ash and chemical nutrients, were established to compare the effects of straw removal (CK), straw return (SR), and straw burned return (SBR).  Compared to CK, long-term SR tended to improve the yield of early season rice (P=0.057), and significantly increased total organic carbon (TOC) and microbial biomass carbon (MBC) in double-cropped rice paddies.  While SBR had no effect on TOC, it decreased light fraction organic carbon (LFOC) in early rice and easily oxidizable organic carbon (EOC) in late rice, significantly increased dissolved organic carbon (DOC), and significantly decreased soil pH.  These results showed that MBC was the most sensitive indicator for assessing changes of SOC in the double-cropped rice system due to long-term straw return.  In addition, the different effects on SOC fraction sizes between SR and SBR were attributed to the divergent trends in most of the soil enzyme activities in the early and late rice that mainly altered DOC, while DOC was positively affected by β-xylosidase in both early and late rice.  We concluded that straw return was superior to straw burned return for improving SOC fractions, but the negative effects on soil enzyme activities in late rice require further research.

Select

Nitrogen release and re-adsorption dynamics on crop straw residue during straw decomposition in an Alfisol LI Ji-fu, ZHONG Fang-fang 2021, 20(1): 248-259.  DOI: 10.1016/S2095-3119(20)63238-5 Abstract ( )   PDF in ScienceDirect   Returning crop straw to the field not only improves the nitrogen (N) supplying capacity and N retention of soil but also decreases the amount of rural organic waste and prevents air pollution.  Therefore, understanding the mechanisms of the N release and re-adsorption dynamics on crop straw residue during straw decomposition in agricultural soil is important, and this understanding can help us strengthen N fertilizer management during the crop growth period.  An on-farm incubation experiment was conducted in the Jianghan Plain in Central China under flooded conditions using the nylon mesh bag method.  Results showed that the decomposition rate of crop straw was much faster at the beginning of the incubation stage, whereas it was steady during the later stage with no observed differences among the three types of crop straw.  After 120 d of incubation, the cumulative decomposition proportion of rice straw, wheat straw and rape straw was 72.9, 56.2, and 66.9%, respectively.  The proportion of N that released from the three crop straws was 52.0, 54.4 and 54.9%, respectively.  The zeta potentials and Brunauer, Emmett and Teller (BET) surface area of the rice, wheat and rape straw residues increased gradually as the decomposition period progressed.  The water adsorption capacity of the rice straw was significantly affected during the decomposition period.  The saturated water adsorption capacity of rice straw was the highest at 30 d of decomposition (4.17 g g–1) and then decreased slightly.  The saturated water adsorption of wheat and rape straws reached the lowest value at 30 d and then gradually increased and became stable.  All the results demonstrated that crop straw and straw residue can re-adsorb NH4+ ions from the surrounding solution.  The re-adsorption was affected by the decomposition period and concentration of exogenous NH4+ and was independent of the crop species via the combined efforts of physical and chemical adsorption, ion exchange and water retention on residue surfaces.  Future studies will focus on straw returning and N fertilizer application at different levels of moisture content of the soil reduce potential negative effects such as water-logging and excess N caused by the straw substrate.

Select

Optimization of water and nitrogen management for surge-root irrigated apple trees in the Loess Plateau of China DAI Zhi-guang, FEI Liang-jun, ZENG Jian, HUANG De-liang, LIU Teng 2021, 20(1): 260-273.  DOI: 10.1016/S2095-3119(20)63283-X Abstract ( )   PDF in ScienceDirect   The Loess Plateau is one of the main regions for growing apple trees in China, but a shortage of water resources and low utilization of nitrogen have restricted its agricultural development.  A 2-year field experiment was conducted which included three levels of soil water content (SWC), 90–75%, 75–60%, and 60–45% of field capacity, and five levels of nitrogen application (Napp), 0.7, 0.6, 0.5, 0.4 and 0.3 kg/plant.  The treatments were arranged in a strip-plot design with complete randomized blocks with three replications.  For both years, the water and Napp had significant (P<0.05) effects on leaf area index (LAI), yield, water use efficiency (WUE) and nitrogen partial factor productivity (NPFP) while the interaction effect of water and Napp on yield, WUE and NPFP was significant (P<0.05) in 2018, and not in 2017.  For the same SWC level, WUE first increased, then decreased as Napp increased, while NPFP tended to decrease, but the trend of LAI with different Napp was closely related to SWC.  At the same Napp, the LAI increased as SWC increased, while the WUE and NPFP first increased, then decreased, but the yield showed different trends as the SWC increased.  The dualistic and quadric regression equations of water and Napp indicate that the yield, WUE and NPFP cannot reach the maximum at the same time.  Considering the coupling effects of water and Napp on yield, WUE and NPFP in 2017 and 2018, the SWC level shall be controlled in 75–60% of field capacity and the Napp is 0.45 kg/plant, which can be as the suitable strategy of water and Napp management for the maximum comprehensive benefits of yield, WUE and NPFP for apple trees in the Loess Plateau and other regions with similar environments.

Select

Estimating daily actual evapotranspiration of a rice–wheat rotation system in typical farmland in the Huai River Basin using a two-step model and two one-step models LI Meng, CHU Rong-hao, Abu Reza Md. Towfiqul ISLAM, JIANG Yue-lin, SHEN Shuang-he 2021, 20(1): 274-288.  DOI: 10.1016/S2095-3119(20)63223-3 Abstract ( )   PDF in ScienceDirect   The objective of this study is to evaluate the performance of three models for estimating daily evapotranspiration (ET) by employing flux observation data from three years (2007, 2008 and 2009) during the growing seasons of winter wheat and rice crops cultivated in a farmland ecosystem (Shouxian County) located in the Huai River Basin (HRB), China.  The first model is a two-step model (PM−Kc); the other two are one-step models (e.g., Rana−Katerji (R−K) and advection-aridity (AA)).  The results showed that the energy closure degrees of eddy covariance (EC) data during winter wheat and rice-growing seasons were reasonable in the HRB, with values ranging from 0.84 to 0.91 and R2 of approximately 0.80.  Daily ET of winter wheat showed a slow decreasing trend followed by a rapid increase, while that of rice presented a decreasing trend after an increase.  After calibrating the crop coefficient (Kc), the PM–Kc model performed better than the model using the Kc recommended by the Food and Agricultural Organization (FAO).  The calibrated key parameters of the R−K model and AA model showed better universality.  After calibration, the simulation performance of the PM−Kc model was satisfactory.  Both the R−K model and AA model underestimated the daily ET of winter wheat and rice.  Compared with that of the R−K model, the simulation result of the AA model was better, especially in the simulation of daily ET of rice.  Overall, this research highlighted the consistency of the PM−Kc model to estimate the water demand for rice and wheat crops in the HRB and in similar climatic regions in the world.

Select

Impact of climate change on maize yield in China from 1979 to 2016 WU Jian-zhai, ZHANG Jing, GE Zhang-ming, XING Li-wei, HAN Shu-qing, SHEN Chen, KONG Fan-tao 2021, 20(1): 289-299.  DOI: 10.1016/S2095-3119(20)63244-0 Abstract ( )   PDF in ScienceDirect   Climate change severely impacts agricultural production, which jeopardizes food security.  China is the second largest maize producer in the world and also the largest consumer of maize.  Analyzing the impact of climate change on maize yields can provide effective guidance to national and international economics and politics.  Panel models are unable to determine the group-wise heteroscedasticity, cross-sectional correlation and autocorrelation of datasets, therefore we adopted the feasible generalized least square (FGLS) model to evaluate the impact of climate change on maize yields in China from 1979–2016 and got the following results: (1) During the 1979–2016 period, increases in temperature negatively impacted the maize yield of China.  For every 1°C increase in temperature, the maize yield was reduced by 5.19 kg 667 m–2 (1.7%).  Precipitation increased only marginally during this time, and therefore its impact on the maize yield was negligible.  For every 1 mm increase in precipitation, the maize yield increased by an insignificant amount of 0.043 kg 667 m–2 (0.014%).  (2) The impacts of climate change on maize yield differ spatially, with more significant impacts experienced in southern China.  In this region, a 1°C increase in temperature resulted in a 7.49 kg 667 m–2 decrease in the maize yield, while the impact of temperature on the maize yield in northern China was insignificant.  For every 1 mm increase in precipitation, the maize yield increased by 0.013 kg 667 m–2 in southern China and 0.066 kg 667 m–2 in northern China.  (3) The resilience of the maize crop to climate change is strong.  The marginal effect of temperature in both southern and northern China during the 1990–2016 period was

Food Science

Select

Use of two-stage dough mixing process in improving water distribution of dough and qualities of bread made from wheat–potato flour YIN Jian, CHENG Li, HONG Yan, LI Zhao-feng, LI Cai-ming, BAN Xiao-feng, GU Zheng-biao 2021, 20(1): 300-310.  DOI: 10.1016/S2095-3119(20)63433-5 Abstract ( )   PDF in ScienceDirect   The two-stage dough mixing process was innovated to improve the qualities of bread made from potato flour (PF) and wheat flour at a ratio of 1:1 (w/w).  The final dough was first prepared from wheat flour before being added with PF.  The effects of the method on enhancing the dough qualities were verified, and the distribution of water in gluten-gelatinized starch matrix of the doughs was investigated.  We observed that the bread qualities were improved, as reflected by the increase of specific volume from 2.26 to 2.96 mL g–1 and the decrease of crumb hardness from 417.93 to 255.57 g.  The results from rheofermentometric measurements showed that the dough mixed using the developed mixing method had higher maximum dough height value, time of dough porosity appearance, and gas retention coefficient, as well as enhanced gluten matrix formation compared to that mixed by the traditional mixing method.  The results from low-field nuclear magnetic resonance confirmed that the competitive water absorption between gluten and gelatinized starch could restrict the formation of gluten network in the dough mixed using the traditional mixing process.  Using the novel mixing method, gluten could be sufficiently hydrated in stage 1, which could then weaken the competitive water absorption caused by gelatinized starch in stage 2; this could also be indicated by the greater mobility of proton in PF and better development of gluten network during mixing.

Select

ATP regulates the phosphorylation and degradation of myofibrillar proteins in ground ovine muscle REN Chi, HOU Cheng-li, ZHANG De-quan, LI Xin, XIAO Xiong, BAI Yu-qiang 2021, 20(1): 311-318.  DOI: 10.1016/S2095-3119(20)63361-5 Abstract ( )   PDF in ScienceDirect   Phosphorylation post-translational modification plays an important role in postmortem muscle quality traits.  Adenosine triphosphate (ATP) is an energy source and a key substrate of phosphorylation which provides the phosphatase groups to proteins in the presence of protein kinases.  However, in postmortem muscle, the effects of ATP content on phosphorylation are poorly studied.  The study investigated the effect of ATP on protein phosphorylation and degradation in postmortem ovine muscle.  The ground muscle with/without additional ATP were treated/control groups and stored at 25 and 4°C, respectively.  The ATP content led to different changes of pH value between the ATP-treated and control groups.  The phosphorylation level of myofibrillar proteins was higher (P<0.05) in ATP-treated group compared to the control group at both temperatures, which suggested that ATP played a vital role in postmortem protein phosphorylation.  A slower degradation rate of μ-calpain, desmin and troponin T was observed in the ATP-treated group which showed that there was a negative relationship between ATP level and the degradation of proteins.  These observations clearly highlighted the role of ATP on the development of meat quality by regulating the phosphorylation and degradation of myofibrillar proteins in postmortem ovine muscle.

Agricultural Economics and Management

Select

Driving factors of direct greenhouse gas emissions from China’s pig industry from 1976 to 2016 DAI Xiao-wen, Zhanli SUN, Daniel MÜLLER 2021, 20(1): 319-329.  DOI: 10.1016/S2095-3119(20)63425-6 Abstract ( )   PDF in ScienceDirect   Livestock cultivation is a significant source of greenhouse gas (GHG) emissions, accounting for 14.5% of the total anthropogenic emissions.  China is responsible for a considerable share of the global livestock emissions, particularly caused by pork production.  We used the Kaya identity and the logarithmic mean Divisia index (LMDI) to decompose the national annual GHG emissions from enteric fermentation and manure management in pig farming in China from 1976 to 2016.  We decomposed the sources of the emissions into five driving factors: (1) technological progress (e.g., feed improvement); (2) structural adjustment in the livestock sector; (3) structural adjustment in agriculture; (4) affluence; and (5) population growth.  The results showed that the net GHG emissions from the pig sector in China increased 16 million tons (Mt) of carbon dioxide equivalents (CO2eq) during the study period.  The decomposition analysis revealed that structural adjustment in agriculture, growing affluence, and population growth contributed to an increase of the GHG emissions of pork production by 23, 41, and 13 Mt CO2eq, respectively.  The technological progress and structural changes in animal husbandry mitigated emissions by –51 and –11 Mt CO2eq, respectively.  Further technological progress in pig production and optimizing the economic structures are critical for further reducing GHG emissions in China’s pig industry.  Our results highlight the dominant role of technological changes for emission reductions in the pig farming.

Select

The dynamic impact of income and income distribution on food consumption among adults in rural China LI Lei, ZHAI Shi-xian, BAI Jun-fei 2021, 20(1): 330-342.  DOI: 10.1016/S2095-3119(20)63239-7 Abstract ( )   PDF in ScienceDirect   Previous studies have demonstrated that income has a significant effect on food demand in rural China.  However, little research has focused on the dynamic impact of income and income distribution on food demand in rural China.  Using China Health and Nutrition Survey data, this study employs a consistent two-step quadratic almost ideal demand system model, with addressed problems of endogeneity of total expenditure and zero shares, to estimate the food demand elasticities among adults in rural areas with regard to the different income strata.  The results show that changes in income and income strata have significant effects on food demand in rural areas.  Except for grains, all other food groups, including vegetables, oils and fats, animal products, and other foods, have positive income elasticities, and the rise in the income strata will lead to declining income elasticities for grains, vegetables, oils and fats, and