2022 Vol. 21 No. 12 Previous Issue    Next Issue

    Special Focus: Integrated Pest Management and Plant Health
    Crop Science
    Agro-ecosystem & Environment
    Food Science
    Short Communication

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    Special Focus: Integrated Pest Management and Plant Health
    Editorial — Integrated pest management and plant health
    ZHOU Xue-ping, TIAN Fang
    2022, 21(12): 3417-3419.  DOI: 10.1016/j.jia.2022.10.013
    Abstract ( )   PDF in ScienceDirect  

    Crop production and livelihoods of smallholder farmers are often threatened by crop insect pests and diseases worsening the insecurity of food.  Globalization has rapidly increased the introduction and threats of invasive pests.  Climate change results in a changed suitability of landscapes to pests, further increasing the threat and uncertainty of their impact.  Providing innovative technologies for sustainable pest management to smallholder farmers is urgently needed for food security and eliminating poverty.  

    The most devasting diseases and insect pests to major crops such as rice, wheat, maize and potato contribute to the largest yield losses in the world.  Under the support of the Food and Agriculture Organization (FAO), Chinese plant protection scientists, in collaboration with experts of different regions, carried out a specific project to prioritize top crop diseases and insect pests that affect smallholder farmers’ production globally.  After evaluation by relevant global experts, top 10 crop diseases and insect pests have been assessed as six crop diseases and four insect pests, namely cereal blast disease, potato late blight, wheat rust disease, Fusarium head blight, maize lethal necrosis disease, banana Fusarium wilt (TR4), rice planthopper, wheat aphid, whitefly, and oriental fruit fly.  Integrated pest management (IPM) guidelines for the identified diseases and insect pests have been formulated, and will be shared through a global knowledge platform.  To share the knowledge with more researchers, the IPM of four major diseases including cereal blast disease, Fusarium head blight, maize lethal necrosis disease and potato late blight were further reviewed and presented in this special focus.  

    The first case study is cereal blast disease caused by fungal pathogen Magnaporthe oryzae (Zhang et al. 2022), which is a destructive filamentous fungus that infects many plants including most economically important food crops, rice, wheat, pearl millet and finger millet (Chakraborty et al. 2021; Hossain 2022).  Different pathovars of M. oryzae often infect different host plants with high specificity.  The rice blast disease caused by the Oryza pathotype (MoO) of M. oryzae can result in 10–30% yield loss in rice-growing countries, posing a major threat to rice production, especially in the small-scale farming system (Mutiga et al. 2021).  The Triticum pathotype (MoT), causing wheat blast disease, was first found in Brazil in 1985.  It has now spread to other countries in South America, and also Asian countries such as Bangladesh (Islam et al. 2016).  Wheat blast disease can result in an average yield loss of 51% in the affected field, becoming one of the most fearsome wheat diseases (Islam et al. 2020).  Because of low fungicide efficacy against the blast diseases and lack of availability of resistant varieties, control of rice and wheat blast diseases is difficult.  A combination of management strategies including early detection and utilization of biopesticides was proposed (Zhang et al. 2022), providing some helpful insights for fighting these devasting cereal blast diseases.  

    The second case study is the fusarium head blight (FHB) caused by FHB pathogens, which are mainly the Fusarium graminearum species complex (Chen et al. 2022).  FHB is one of the most important diseases that affects wheat production worldwide (Summerell 2019).  In general, a severe FHB epidemic occurred every four or five years in the most of wheat production regions.  Since 2010, the outbreaks of FHB have become more frequent in China.  Besides causing yield loss in affected crop field, FHB also produces mycotoxin contaminating the harvested grains, which are harmful to humans and livestock (Stepien and Chelkowski 2010).  According to the economic importance and toxicity of FHB, F. graminearum is considered as one of the world’s top 10 fungal phytopathogens (Dean et al. 2012).  Breeding resistant cultivars has been considered as the most effective strategy against FHB (Wegulo et al. 2015).  Rational use of chemical pesticides, and potential biopesticides, and good agronomic practices are also important components in the IPM programme for FHB.   

    The third case study is the maize lethal necrosis disease (MLND), which is a relatively new viral disease on maize (Zhan et al. 2022).  The MLND is caused by the co-infection of maize chlorotic mottle virus (MCMV) and one of cereal-infecting potyviruses, and the symptoms on maize include leaf necrosis, premature aging, small cobs and even plant death (Redinbaugh and Stewart 2018).  First reported in Americas in 1970s and 1980s, the MLND has now spread to more than fifteen countries in the Americas, Asia and Africa (Wangai et al. 2012).  The outbreaks of MLND in several Asian and African countries caused devastating damage to maize production with large impacts on smallholder farmers (Mahuku et al. 2015).  Integrated management of MLND involves effective detection methods such as serological methods, nucleic acid-based methods, and next-generation sequencing.  The practices, such as using certified seeds, sanitary measures, crop rotation, and tolerant or resistant varieties, have been considered as the effective, economical and eco-friendly approach to prevent and control MLND.

    The fourth case study is the potato late blight (PLB) disease (Dong and Zhou 2022).  PLB, caused by the fungal-like oomycete pathogen Phytophthora infestans, is a devastating disease worldwide that led to the infamous Irish potato famine of the 1840s.  Besides the primary host potato, P. infestans also infects other solanaceous plants such as tomato, petunia and nightshade.  These infected plants can become pathogen inoculum to potato (Kirk et al. 2003).  Originated from Central Mexico or South America, this disease has spread to almost all major potato-producing countries including the United States, Canada, China, and India (Fry et al. 2015).  Up to now, PLB remains the most important biotic constraint to potato production worldwide and presents a major threat to global food security, especially for under-developed areas that heavily depend on potato as the major source of food (Cucak et al. 2021).  Careful agronomic practices, such as using pathogen-free seed, serve as the good start for the successful management of PLB.  Chemical fungicides remain the most effective means to control the pathogen.  However, these chemical fungicides should be used more scientifically to avoid over-dosage and high cost.  Some potential environmental-friendly biopesticides have been identified (He et al. 2021).  Additionally, new technologies which may bring some innovative solutions to control PLB are also proposed.  

    The desert locust (Schistocerca gregaria), the most destructive migratory insect pest in the world, was also selected in the special focus (Li et al. 2022).  Desert locust is an omnivorous insect, feeding on more than 300 various host plants including many cultivated crops and wild plants (Li et al. 2021).  Formation of desert locust swarms and the outbreak of desert locusts are induced by a combination of environmental stimuli.  During its outbreak and migration, desert locust can cause serious damage to cultivated crops, such as cotton, alfalfa, beans, wheat, barley, corn, flax, tobacco, tomato, potato, and melons, posing a major threat to food security and rural livelihoods.  Since the 20th century, there have been 15 outbreaks of the desert locust, affecting about 30 million km2 of Africa and Asia continents and the lives of 850 million people in 65 countries (Ceccato et al. 2007; Divi 2020).  Studies demonstrate the correlation between poor early childhood health and the desert locust swarm outbreak (Kien and Nguyen 2022).  To date, much research has been conducted regarding the ecology and management of desert locusts.  Climate change resulted in more favorable conditions, which is a major factor contributing to the recent outbreak of desert locust in 2020 (Peng et al. 2020).  A critical component of preventive management programs is being able to locate significant infestations rapidly.  The FAO provides forecasts, early warning and alerts on the timing, scale and location of invasions and breeding through its global Desert Locust Information Service (DLIS).  Integrated management of desert locust, mainly including physical control methods, chemical insecticides, microbial pesticides, and biocontrol methods, are summarized in ths review (Li et al. 2022).  

    Occurrence of plant diseases and insect pests have been worsened by climate change in many aspects.  Prevention of yield loss of major crops is critical for achieving global food security.  Not only the IPM strategies should be adopted, but also the inter-government cooperation should be encouraged to share knowledge, information and innovative solutions, and to jointly tackle with challenges caused by transboundary pests.  All these efforts are needed to achieve the United Nations Sustainable Development Goals (SDGs) of 2030 Agenda for Sustainable Development.

    Integrated pest management programme for cereal blast fungus Magnaporthe oryza
    ZHANG Hai-feng, Tofazzal ISLAM, LIU Wen-de
    2022, 21(12): 3420-3433.  DOI: 10.1016/j.jia.2022.08.056
    Abstract ( )   PDF in ScienceDirect  

    Magnaporthe oryzae, the causal agent of blast diseases, is a destructive filamentous fungus that infects many plants including most economically important food crops, rice, wheat, pearl millet and finger millet.  Magnaporthe oryzae has numerous pathotypes because of its high host-specificity in the field.  The Oryza pathotype (MoO) of Moryzae is the most devastating pathogen of rice, causing 10–30% yield loss in the world.  On the other hand, the Triticum pathotype (MoT) causes blast disease in wheat, which is now a serious threat to wheat production in some South American countries, Bangladesh and Zambia.  Because of low fungicide efficacy against the blast diseases and lack of availability of resistant varieties, control of rice and wheat blast diseases is difficult.  Therefore, an integrated management programme should be adopted to control these two diseases in the field.  Here, we introduced and summarized the classification, geographical distribution, host range, disease symptoms, biology and ecology, economic impact, and integrated pest management (IPM) programme of both rice and wheat blast diseases.Magnaporthe oryzae, the causal agent of blast diseases, is a destructive filamentous fungus that infects many plants including most economically important food crops, rice, wheat, pearl millet and finger millet.  Magnaporthe oryzae has numerous pathotypes because of its high host-specificity in the field.  The Oryza pathotype (MoO) of Moryzae is the most devastating pathogen of rice, causing 10–30% yield loss in the world.  On the other hand, the Triticum pathotype (MoT) causes blast disease in wheat, which is now a serious threat to wheat production in some South American countries, Bangladesh and Zambia.  Because of low fungicide efficacy against the blast diseases and lack of availability of resistant varieties, control of rice and wheat blast diseases is difficult.  Therefore, an integrated management programme should be adopted to control these two diseases in the field.  Here, we introduced and summarized the classification, geographical distribution, host range, disease symptoms, biology and ecology, economic impact, and integrated pest management (IPM) programme of both rice and wheat blast diseases.

    An integrated pest management program for managing fusarium head blight disease in cereals
    CHEN A-hai, Tofazzal ISLAM, MA Zhong-hua
    2022, 21(12): 3434-3444.  DOI: 10.1016/j.jia.2022.08.053
    Abstract ( )   PDF in ScienceDirect  

    Fusarium head blight (FHB) is a worldwide devastating disease of small grain cereals and Fusarium graminearum species complex (FGSC) is the major pathogen causing the disease.  The epidemics of FHB lead to the reduction of grain yield and economic losses.  Additionally, mycotoxins produced by the FHB pathogens are hazardous to the health of human and livestock.  In this review, we summarize the epidemiology of FHB, and introduce effects of this disease on economy, environment and food safety.  We focus on the integrated management approaches for controlling FHB including agronomic practices, resistant cultivars, chemical control, and biocontrol.  In addition, we also discuss the potential novel management strategies against FHB and mycotoxin.

    Recent progress in maize lethal necrosis disease: from pathogens to integrated pest management
    ZHAN Bin-hui, YANG Xiu-ling, Steven A. LOMMEL, ZHOU Xue-ping
    2022, 21(12): 3445-3455.  DOI: 10.1016/j.jia.2022.08.050
    Abstract ( )   PDF in ScienceDirect  
    Maize (Zea mays), as a staple food and an important industrial raw material, has been widely cultivated for centuries especially by smallholder farmers. Maize lethal necrosis disease (MLND) is a serious disease infecting maize, which caused devastating damage in the African region recently. MLND is induced by co-infection of maize chlorotic mottle virus and one of several cereal-infecting viruses in the Potyviridae family, with the symptoms ranging from chlorotic mottle to plant death at different infection stages. Integrated pest management for MLND needs strengthening detection, focusing on prevention and effective control. Early detection system of MLND has been successfully established by serological methods, nucleic acid-based methods, next-generation sequencing et al. The practices, such as using certified seeds, sanitary measures, crop rotation, tolerant or resistant varieties etc., have been considered as the effective, economical and eco-friendly way to prevent and control MLND.

    Potato late blight caused by Phytophthora infestans: From molecular interactions to integrated management strategies
    DONG Suo-meng, ZHOU Shao-qun
    2022, 21(12): 3456-3466.  DOI: 10.1016/j.jia.2022.08.060
    Abstract ( )   PDF in ScienceDirect  

    Over 170 years after the infamous Irish Potato Famine, potato late blight (PLB) caused by Phytophthora infestans remains the single most devastating disease of global potato production, causing up to 10 billion USD in yield loss and management costs.  Through decades of research, growers and agronomists in the field as well as laboratory scientists have made significant progress in understanding the molecular pathogenesis process of this critical pathosystem and effective management strategies to control PLB.  Yet, the need to feed an ever-increasing global population under changing climate demands continued improvement in efficient and sustainable PLB management schemes that can be implemented across a broad economic spectrum.  In this review, we briefly summarize the current understanding of the molecular interaction between P. infestans and its host plants, highlight the current integrated pest management strategy to control PLB on local and continental scales, and discuss the potential of further improvement of sustainable PLB control through genetic enhancement of crop resistance and emerging crop protection technologies.

    IPM - Biological and integrated management of desert locust
    LI Shuang, FENG Shi-qian, Hidayat ULLAH, TU Xiong-bing, ZHANG Ze-hua
    2022, 21(12): 3467-3487.  DOI: 10.1016/j.jia.2022.09.017
    Abstract ( )   PDF in ScienceDirect  

    Locusts have caused periodic disasters in the recorded history of humankind.  Up to now, locust disaster is still the biggest threat to the world’s agricultural production.  The desert locust Schistocerca gregaria is one of the most harmful locusts, which has caused massive food crises, economic losses, and ecological disasters.  The desert locust is a migratory insect pest that occurs year-round in the tropic and subtropical regions.  Under the wind and seasonal alternation, it moves and flies in the African continent and West Asia.  Desert locust damages the stems and leaves of more than 300 plants, including Gramineae, Tribulus terrestris, and Euphorbiaceae.  Locusts cause devastating disasters to local plants, especially field crops, and significantly threaten food security.  To date, voluminous research has been conducted regarding the ecology and management of desert locusts.  This review represents an effort to summarize the basic information on the biology and ecology, distribution, damage, and economic impact of desert locusts, examine the recent developments in integrated locust management, and make recommendations for future research.  

    Crop Science
    Quantitative analysis of the effect of the PAY1 gene on rice canopy structure during different reproductive stages
    WEI Cui-lan, CAO Bing-shuai, HUA Shan, LI Bao-guo
    2022, 21(12): 3488-3500.  DOI: 10.1016/j.jia.2022.08.093
    Abstract ( )   PDF in ScienceDirect  
    The leaf and stem types are core structural characteristics of the rice phenotype that determine the light interception ability of the canopy and directly affect crop yield.  The PLANT ARCHITECTURE AND YIELD 1 (PAY1) gene has been shown to alter the prostrate growth habit of wild rice and to inhibit the wild rice prostrate growth gene PROSTRATE GROWTH 1 (PROG1).  In this paper, the wild rice introgression line YIL55, which contains the PROG1 gene; its mutant, PAY1; and its parent, TQ, were used as test varieties to construct three-dimensional (3D) canopy structure models based on 3D digital assay technology.  On this basis, quantitative analyses of the PAY1 gene and the plant leaf and stem types at the jointing, heading and filling stages were performed.  Under the influence of the PAY1 gene, the plant stem and leaf angles from vertical decreased significantly; the plants were upright, with larger leaves; the culm angle changed from loose to compact; and the average tiller angle during the three key reproductive stages decreased from 44.9, 28.5 and 21.3° to 17.6, 8.4 and 10.5°, respectively.  Moreover, the PAY1 mutant retained the PROG1 gene characteristic of exhibiting dynamic changes in the tiller angle throughout the growth period, and its culm angle changed from loose during the jointing stage to compact during the heading stage.  The measurements of photosynthetically active radiation (PAR) in the canopy also showed that the mutant PAY1 allowed more PAR to reach the bottom of the canopy than the other varieties.  The light-extinction coefficients for PAY1 at the jointing, heading and filling stages were 0.535, 0.312 and 0.586, respectively, which were lower than those of the other two varieties.  In this study, the influence of the PAY1 gene on rice canopy structural characteristics was quantitatively analyzed to provide effective canopy structure parameters for breeding the ideal plant type.
    QTL analysis of the developmental changes in cell wall components and forage digestibility in maize (Zea mays L.)
    LI Kun, YANG Xue, LIU Xiao-gang, HU Xiao-jiao, WU Yu-jin, WANG Qi, MA Fei-qian, LI Shu-qiang, WANG Hong-wu, LIU Zhi-fang, HUANG Chang-ling
    2022, 21(12): 3501-3513.  DOI: 10.1016/j.jia.2022.08.090
    Abstract ( )   PDF in ScienceDirect  
    Cell wall architecture plays a key role in stalk strength and forage digestibility.  Lignin, cellulose, and hemicellulose are the three main components of plant cell walls, and they can impact stalk quality by affecting the structure and strength of the cell wall.  To explore cell wall development during secondary cell wall lignification in maize stalks, conventional and conditional genetic mapping were used to identify the dynamic quantitative trait loci (QTLs) of the cell wall components and digestibility traits during five growth stages after silking.  Acid detergent lignin (ADL), cellulose (CEL), acid detergent fiber (ADF), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD) were evaluated in a maize recombinant inbred line (RIL) population.  ADL, CEL, ADF, and NDF gradually increased from 10 to 40 days after silking (DAS), and then they decreased.  IVDMD initially decreased until 40 DAS, and then it increased slightly.  Seventy-two QTLs were identified for the five traits, and each accounted for 3.48–24.04% of the phenotypic variation.  Six QTL hotspots were found, and they were localized in the 1.08, 2.04, 2.07, 7.03, 8.05, and 9.03 bins of the maize genome.  Within the interval of the pleiotropic QTL identified in bin 1.08 of the maize genome, six genes associated with cell wall component biosynthesis were identified as potential candidate genes for stalk strength as well as cell wall-related traits.  In addition, 26 conditional QTLs were detected in the five stages for all of the investigated traits.  Twenty-two of the 26 conditional QTLs were found at 30 DAS conditioned using the values of 20 DAS, and at 50 DAS conditioned using the values of 40 DAS.  These results indicated that cell wall-related traits are regulated by many genes, which are specifically expressed at different stages after silking.  Simultaneous improvements in both forage digestibility and lodging resistance could be achieved by pyramiding multiple beneficial QTL alleles identified in this study.
    Genome-wide association study and metabolic pathway prediction of barrenness in maize as a response to high planting density
    ZHANG Xu-huan, LIU Hao, MA Xu-hui, ZHOU Gu-yi, RUAN Hong-qiang, CUI Hong-wei, PANG Jun-ling, SIFFAT Ullah Khan, ZONG Na, WANG Ren-zhong, LENG Peng-fei, ZHAO Jun
    2022, 21(12): 3514-3523.  DOI: 10.1016/j.jia.2022.08.089
    Abstract ( )   PDF in ScienceDirect  

    Increasing the planting density is one way to enhance grain production in maize.  However, high planting density brings about growth and developmental defects such as barrenness, which is the major factor limiting grain yield.  In this study, the barrenness was characterized in an association panel comprising 280 inbred lines under normal (67 500 plants ha–1, ND) and high (120 000 plants ha–1, HD) planting densities in 2017 and 2018.  The population was genotyped using 776 254 single nucleotide polymorphism (SNP) markers with criteria of minor allele frequency >5% and <20% missing data.  A genome-wide association study (GWAS) was conducted for barrenness under ND and HD, as well as the barrenness ratio (HD/ND), by applying a Mixed Linear Model that controls both population structure and relative kinship (Q+K).  In total, 20 SNPs located in nine genes were significantly (P<6.44×10–8) associated with barrenness under the different planting densities.  Among them, seven SNPs for barrenness at ND and HD were located in two genes, four of which were common under both ND and HD.  In addition, 13 SNPs for the barrenness ratio were located in seven genes.  A complementary pathway analysis indicated that the metabolic pathways of amino acids, such as glutamate and arginine, and the mitogen-activated protein kinase (MAPK) signaling pathway might play important roles in tolerance to high planting density.  These results provide insights into the genetic basis of high planting density tolerance and will facilitate high yield maize breeding.

    Identification of the genetic locus associated with the crinkled leaf phenotype in a soybean (Glycine max L.) mutant by BSA-Seq technology
    OCHAR Kingsley, SU Bo-hong, ZHOU Ming-ming, LIU Zhang-xiong, GAO Hua-wei, SOBHI F. Lamlom, QIU Li-juan
    2022, 21(12): 3524-3539.  DOI: 10.1016/j.jia.2022.08.095
    Abstract ( )   PDF in ScienceDirect  

    The leaf is the main photosynthetic organ of plants, and it plays a significant role in the yield of crop species.  Identifying the causal mutations and candidate genes that underlie leaf phenotypic variation is an important breeding target in soybean grain yield improvement.  An ethyl methyl sulfonate (EMS)-induced soybean mutant DWARFCRINKLEDLEAF1 (DCL1) with an aberrant crinkled leaf phenotype was identified in the background of the soybean cultivar Zhongpin 661 (Zp661).  We constructed an F2 segregating population from a cross between Zp661 and DCL1 in order to investigate the genomic locus associated with the crinkled leaf trait.  Using bulk segregant analysis (BSA) combined with the whole-genome resequencing method, the Euclidean distance (ED) correlation algorithm detected 12 candidate genomic regions with a total length of 20.32 Mb that were linked to the target trait.  Following a comparative analysis of the sequence data for the wild-type and mutant pools, only one single nucleotide mutation (C:G>T:A) located on the first exon of Glyma.19G207100 was found to be associated with the trait.  Candidate gene validation based on a CAPS marker derived from the detected single-nucleotide polymorphism (SNP) indicated a nucleotide polymorphism between the two parents.  Therefore, our findings reveal that Glyma.19G207100, which is renamed as GLYCINE MAX DWARF CRINKLED LEAF 1 (GmDCL1), is a promising candidate gene involved in the morphogenesis of the crinkled leaf trait of the soybean mutant DCL1.  This study provides a basis for the functional validation of this gene, with prospects for soybean breeding targeting grain yield enhancement.

    Genome-wide identification and characterization of the JAZ gene family and its expression patterns under various abiotic stresses in Sorghum bicolor
    DU Qiao-li, FANG Yuan-peng, JIANG Jun-mei, CHEN Mei-qing, LI Xiang-yang, XIE Xin
    2022, 21(12): 3540-3555.  DOI: 10.1016/j.jia.2022.08.104
    Abstract ( )   PDF in ScienceDirect  

    The jasmonate ZIM domain (JAZ) protein belongs to the TIFY ((TIF[F/Y]XG) domain protein) family, which is composed of several plant-specific proteins that play important roles in plant growth, development, and defense responses.  However, the mechanism of the sorghum JAZ family in response to abiotic stress remains unclear.  In the present study, a total of 17 JAZ genes were identified in sorghum using a Hidden Markov Model search.  In addition, real-time quantification polymerase chain reaction (RT-qPCR) was used to analyze the gene expression patterns under abiotic stress.  Based on phylogenetic tree analysis, the sorghum JAZ proteins were mainly divided into nine subfamilies.  A promoter analysis revealed that the SbJAZ family contains diverse types of promoter cis-acting elements, indicating that JAZ proteins function in multiple pathways upon stress stimulation in plants.  According to RT-qPCR, SbJAZ gene expression is tissue-specific.  Additionally, under cold, hot, polyethylene glycol, jasmonic acid, abscisic acid, and gibberellin treatments, the expression patterns of SbJAZ genes were distinctly different, indicating that the expression of SbJAZ genes may be coordinated with different stresses.  Furthermore, the overexpression of SbJAZ1 in Escherichia coli was found to promote the growth of recombinant cells under abiotic stresses, such as PEG 6000, NaCl, and 40°C treatments.  Altogether, our findings help us to better understand the potential molecular mechanisms of the SbJAZ family in sorghum in response to abiotic stresses.

    Straw strips mulching: A sustainable technology of saving water and improving efficiency in dryland winter wheat production
    LI Rui, CHAI Shou-xi, CHAI Yu-wei, LI Ya-wei, CHANG Lei, CHENG Hong-bo
    2022, 21(12): 3556-3568.  DOI: 10.1016/j.jia.2022.08.098
    Abstract ( )   PDF in ScienceDirect  

    An improved straw mulching model may be a sustainable agricultural production technology due to its improvements in soil water and the fertilizer environment by the recycling of waste straw resources.  A four-year field experiment was conducted in a randomized block design on the Loess Plateau of northwestern China in 2015–2019, which aimed to study the effects of straw strip mulching (SSM) and conventional flat planting without mulching (CK) on soil water storage, water consumption characteristics, water use efficiency, precipitation use efficiency, winter wheat growth, economic benefits, and nutrient benefits.  The results obtained for the four years showed that the SSM treatment improved soil water storage in the 0–180 cm soil layer over the whole growth period, which was especially obvious in the 0–60 cm soil layer at the jointing and blooming stages.  Compared with CK, SSM increased the contribution rate of precipitation to total evapotranspiration and increased it quite significantly by 20.4 percentage points in the earlier growth period.  SSM significantly reduced soil water storage consumption in the 0–180 cm soil layer and ultimately reduced evapotranspiration by 11.2 mm during the whole period.  In the 0–180 cm soil layer, SSM decreased evapotranspiration by 33.1 mm from the sowing to the jointing stages, but increased it by 19.5 mm from the jointing to the blooming stages.  In addition, SSM improved the water use efficiency of grain yield by 21.6% and improved the precipitation use efficiency of grain yield by 18.6%, and it ultimately increased grain yield by 16.5% through improving spike number by 9.5% and kernel number per spike by 8.9%.  SSM improved the water use efficiency of biomass yield by 13.5% and the precipitation use efficiency of biomass yield by 9.9%, and it ultimately increased biomass yield by 8.7% and plant height by 6.5%.  Furthermore, SSM increased net income by 413 CNY ha–1 and the total amount of straw returned to the field after harvest by 8 876–9 619 kg ha–1.  After returning straw to the field, SSM significantly increased the soil nutrient contents, which could significantly reduce the burden of fertilization by farmers after a few years.  Therefore, straw strip mulching technology could probably be a sustainable and potentially useful practice, which could save water and increase efficiency in rainfed winter wheat production.

    Testing Taylor’s Power Law association of maize interplant variation with mean grain yield
    2022, 21(12): 3569-3577.  DOI: 10.1016/j.jia.2022.08.103
    Abstract ( )   PDF in ScienceDirect  

    Plant-to-plant variability is a crop stability component.  The objective of this study in maize (Zea mays L.) was to test the validity of the theoretical background of the hypothesis that the coefficient of variation (CV) for grain yield per plant and mean yield are connected exponentially, following the Taylor’s Power Law (TPL) Model.  Field experimentation was conducted across two sites, two seasons, and two planting densities.  Densities were the main plots, corresponding to the typical practice of 8.89 plants m–2 (TCD) and the low-input optimal of 5.33 plants m–2 (LCD), while hybrids were the subplots.  Data from 26 subplots in the first site averaged CV values of 22.6% at the TCD and 21.9% at the LCD, and mean yields of 19.1 and 13.9 t ha–1, respectively, following the TPL Model.  The same was true for the second site, with average CVs and means of 41.5% and 14.3 t ha–1 at the TCD and 36.8% and 11.5 t ha–1 at the LCD.  A test was performed on the simple correlation between the logarithms of variances and their respective means to investigate whether there is a systematic variance dependence on mean, thus questioning the reliability of TPL.  The validity of TPL was verified in the first site.  Nevertheless, there was a systematic dependence of yield variance on mean yield in the second site, implying that the CV-yield correlation might be not biologically meaningful.  Conversion of the variance to remove its dependence on the mean did not validate the CV-yield negative relationship, meaning that caution is needed when interpreting the CV as a stability index for intra-crop variation.  Whether the determinant factor of invalidity of TPL was the extensive intra-crop variation in the lower yielding second site can be assessed in future research.

    Overexpression of the apple expansin-like gene MdEXLB1 accelerates the softening of fruit texture in tomato
    CHEN Yan-hui, XIE Bin, AN Xiu-hong, MA Ren-peng, ZHAO De-ying, CHENG Cun-gang, LI En-mao, ZHOU Jiang-tao, KANG Guo-dong, ZHANG Yan-zhen
    2022, 21(12): 3578-3588.  DOI: 10.1016/j.jia.2022.08.030
    Abstract ( )   PDF in ScienceDirect  

    Fruit firmness is an important quality trait of apple fruit texture, and the pre-harvest ripening period is the key period for the formation of apple fruit texture.  Expansin is a cell wall loosing protein family that has four subfamilies: α-expansin (EXPA), β-expansin (EXPB), expansin-like A (EXLA), and expansin-like B (EXLB).  In this study, we investigated the key period of pre-harvest texture formation in ‘Golden Delicious’ apples based on fruit longitudinal diameter, transverse diameter, firmness, tissue structure, respiration intensity, ethylene release rate, and expansin activity.  Within the 10 days before harvest, the fruit was found to reach maturity.  Semi-quantitative RT-PCR revealed that most of the expansins were expressed at the ripening stage before harvest.  The biological function of the EXLB subfamily gene, MdEXLB1, was further identified, and its subcellular localization on the cell wall was confirmed by transient transformation experiments.  Compared with the wild type (WT), the transgenic tomato lines overexpressing MdEXLB1 had lower plant height, earlier fruiting period, fewer days for fruit ripening, higher fruit maturity, lower fruit firmness, higher fruit expansin activity, more discrete flesh cell structure, and accelerated fruit ripening process.  Overall, this is the first study to propose that the apple EXLB subfamily gene, MdEXLB1, has biological functions and plays an important role in promoting fruit ripening and softening.

    Identifying candidate genes involved in trichome formation on carrot stems by transcriptome profiling and resequencing 
    WU Zhe, YANG Xuan, ZHAO Yu-xuan, JIA Li
    2022, 21(12): 3589-3599.  DOI: 10.1016/j.jia.2022.08.032
    Abstract ( )   PDF in ScienceDirect  

    Trichomes are specialized structures developed from epidermal cells and can protect plants against biotic and abiotic stresses.  Trichomes cover carrots during the generative phase.  However, the morphology of the carrot trichomes and candidate genes controlling the formation of trichomes are still unclear.  This study found that carrot trichomes were non-glandular and unbranched hairs distributed on the stem, leaf, petiole, pedicel, and seed of carrot.  Resequencing analysis of a trichome mutant with sparse and short trichomes (sst) and a wild type (wt) with long and dense trichomes on carrot stems was conducted.  A total of 15 396 genes containing nonsynonymous mutations in sst were obtained, including 42 trichome-related genes.  We also analyzed the transcriptome of the trichomes on secondary branches when these secondary branches were 10 cm long between wt and sst and obtained 6 576 differentially expressed genes (DEGs), including 24 trichome-related genes.  qRT-PCR validation exhibited three significantly up-regulated DEGs, 20 significantly down-regulated, and one with no difference.  We considered both the resequencing and transcriptome sequencing analyses and found that 12 trichome-related genes that were grouped into five transcription factor families containing nonsynonymous mutations and significantly down-regulated in sst.  Therefore, these genes are potentially promising candidate genes whose nonsynonymous mutations and down-regulation may result in scarce and short trichomes mutation on carrot stems in sst.

    Agro-ecosystem & Environment
    Co-application of compost or inorganic NPK fertilizer with biochar influenced soil quality, grain yield and net income of rice
    Christian Adler PHARES, Selorm AKABA
    2022, 21(12): 3600-3610.  DOI: 10.1016/j.jia.2022.07.041
    Abstract ( )   PDF in ScienceDirect  

    Most agricultural soils in sub-Saharan Africa are degraded, compromising the grain yield of rice and farmers return on investment.  A 3-year field study was undertaken to explore the effect of the application of compost or inorganic NPK fertilizer applied alone or in combination with biochar on soil quality, grain yield of rice and net income.  The five treatments were laid out using a randomized complete block design with four replications.  The treatments were applied to supply approximately 75 kg N ha–1.  The best fertilizer input was compost+biochar which resulted in the greatest improvement in soil physico-chemical properties by reducing bulk density and increasing porosity and moisture retention, organic matter content, percent nitrogen, available phosphorus and cation exchange capacity.  Apart from treatment with inorganic fertilizer alone, treated soils showed a decrease in pH. Bacterial and fungal counts and basal respiration decreased in soils in the following order: compost+biochar>compost only>inorganic NPK fertilizer+biochar>inorganic NPK fertilizer>control.  The increase in pooled grain yield and net income in response to treatment followed the order: compost+biochar>NPK+biochar>NPK>compost>control.  The findings suggest that the use of compost or NPK alone might improve soil quality and increase grain yield and net income, but it is greatly recommended to co-apply these fertilisers with biochar. 

    Fractionation of soil organic carbon in a calcareous soil after long-term tillage and straw residue management
    LI Teng-teng, ZHANG Jiang-zhou, ZHANG Hong-yan, Chrisite PHRISITE, ZHANG Jun-ling
    2022, 21(12): 3611-3625.  DOI: 10.1016/j.jia.2022.08.072
    Abstract ( )   PDF in ScienceDirect  

    No tillage (NT) and straw return (S) collectively affect soil organic carbon (SOC).  However, changes in the organic carbon pool have been under-investigated.  Here, we assessed the quantity and quality of SOC after 11 years of tillage and straw return on the North China Plain.  Concentrations of SOC and its labile fractions (particulate organic carbon (POC), potassium permanganate-oxidizable organic carbon (POXC), microbial biomass carbon (MBC) and dissolved organic carbon (DOC)), components of DOC by fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) and the chemical composition of SOC by 13C NMR spectroscopy were explored.  Treatments comprised conventional tillage (CT) and NT under no straw return (S0), return of wheat straw only (S1) or return of both wheat straw and maize residue (S2).  Straw return significantly increased the concentrations and stocks of SOC at 0-20 cm depth but no tillage stratified them with enrichment at 0-10 cm and a decrease at 10-20 cm in comparison to CT, especially under S2.  Labile C fractions showed similar patterns of variation to that of SOC, with POC and POXC more sensitive to straw return and the former more sensitive to tillage.  Six fluorescence components of DOC were identified comprising mostly humic-like substances with smaller amounts of fulvic acid-like substances and tryptophan. Straw return significantly decreased the fluorescence index (FI) and autochthonous index (BIX) and increased the humification index (HIX).  No tillage generally increased HIX in topsoil but decreased it and increased the FI and BIX below the topsoil.  The chemical composition of SOC was: O-alkyl C>alkyl-C>aromatic-C>carbonyl-C.  Overall, NT under S2 effectively increased SOC and its labile C forms and DOC humification in topsoil and microbially-derived DOC below the topsoil.  Return of both wheat and maize straw was a particularly strong factor for promoting soil organic carbon in the plough layer, and the stratification of SOC under no tillage may confer long-term influence on carbon sequestration.

    Characteristics of inorganic phosphorus fractions and their correlations with soil properties in three non-acidic soils
    ZHANG Nai-yu, WANG Qiong, ZHAN Xiao-ying, WU Qi-hua, HUANG Shao-min, ZHU Ping, YANG Xue-yun, ZHANG Shu-xiang
    2022, 21(12): 3626-3636.  DOI: 10.1016/j.jia.2022.08.012
    Abstract ( )   PDF in ScienceDirect  

    Understanding the characteristics and influences of various factors on phosphorus (P) fractions is of significance for promoting the efficiency of soil P.  Based on long-term experiments on black soil, fluvo-aquic soil, and loess soil, which belong to Phaeozems, Cambisols, and Anthrosols in the World Reference Base for Soil Resources (WRB), respectively, five fertilization practices were selected and divided into three groups: no P fertilizer (CK/NK), balanced fertilizer (NPK/NPKS), and manure plus mineral fertilizer (NPKM).  Soil inorganic P (Pi) fractions and soil properties were analyzed to investigate the characteristics of the Pi fractions and the relationships between Pi fractions and various soil properties.  The results showed that the proportion of Ca10-P in the sum of total Pi fractions was the highest in the three soils, accounting for 33.5% in black soil, 48.8% in fluvo-aquic soil, and 44.8% in loess soil.  Long-term fertilization practices resulted in periodic changes in soil Pi accumulation or depletion.  For black soil and fluvo-aquic soil, the Pi accumulation was higher in the late period (10–20 years) of fertilization than in the early period (0–10 years) under NPK/NPKS and NPKM, whereas the opposite result was found in loess soil.  The Pi accumulation occurred in all Pi fractions in black soil; mainly in Ca8-P, Fe-P, and Ca10-P in fluvo-aquic soil; and in Ca2-P, Ca8-P, and O-P in loess soil.  Under CK/NK, the soil Pi was depleted mainly in the early period in each of the three soils.  In addition to the labile Pi (Ca2-P) and moderately labile Pi (Ca8-P, Fe-P, Al-P), the Ca10-P in black soil and fluvo-aquic soil and O-P in loess soil could also be used by crops.  Redundancy analysis showed that soil properties explained more than 90% of the variation in the Pi fractions in each soil, and the explanatory percentages of soil organic matter (SOM) were 43.6% in black soil, 74.6% in fluvo-aquic, and 38.2% in loess soil.  Consequently, decisions regarding the application of P fertilizer should consider the accumulation rate and the variations in Pi fractions driven by soil properties in non-acidic soils.

    Statistical analysis of nitrogen use efficiency in Northeast China using multiple linear regression and random forest
    LIU Ying-xia, Gerard B. M. HEUVELINK, Zhanguo BAI, HE Ping, JIANG Rong, HUANG Shao-hui, XU Xin-peng
    2022, 21(12): 3637-3657.  DOI: 10.1016/j.jia.2022.08.054
    Abstract ( )   PDF in ScienceDirect  

    Understanding the spatial-temporal dynamics of crop nitrogen (N) use efficiency (NUE) and the relationship with explanatory environmental variables can support land-use management and policymaking.  Nevertheless, the application of statistical models for evaluating the explanatory variables of space-time variation in crop NUE is still under-researched.  In this study, stepwise multiple linear regression (SMLR) and Random Forest (RF) were used to evaluate the spatial and temporal variation of NUE indicators (i.e., partial factor productivity of N (PFPN); partial nutrient balance of N (PNBN)) at county scale in Northeast China (Heilongjiang, Liaoning and Jilin provinces) from 1990 to 2015.  Explanatory variables included agricultural management practices, topography, climate, economy, soil and crop types.  Results revealed that the PFPN was higher in the northern parts and lower in the center of the Northeast China and PNBN increased from southern to northern parts during the 1990–2015 period.  The NUE indicators decreased with time in most counties during the study period.  The model efficiency coefficients of the SMLR and RF models were 0.44 and 0.84 for PFPN, and 0.67 and 0.89 for PNBN, respectively.  The RF model had higher relative importance of soil and climatic covariates and lower relative importance of crop covariates compared to the SMLR model.  The planting area index of vegetables and beans, soil clay content, saturated water content, enhanced vegetation index in November & December, soil bulk density, and annual minimum temperature were the main explanatory variables for both NUE indicators.  This is the first study to show the quantitative relative importance of explanatory variables for NUE at a county level in Northeast China using RF and SMLR.  This novel study gives reference measurements to improve crop NUE which is one of the most effective means of managing N for sustainable development, ensuring food security, alleviating environmental degradation and increasing farmer’s profitability.

    Food Science
    Development of a texture evaluation system for winter jujube (Ziziphus jujuba ‘Dongzao’)
    KONG Xia-bing, XU Min, WAN Hao-liang, HAN Ling-xi, LIU Xiao-li, LI Qing-jun, HAO Bian-qing, ZHANG Shao-jun, LI Xiao-ming, LIU Yi-hui, NIE Ji-yun
    2022, 21(12): 3658-3668.  DOI: 10.1016/j.jia.2022.09.007
    Abstract ( )   PDF in ScienceDirect  

    Winter jujube (Ziziphus jujuba ‘Dongzao’) is an excellent late maturing variety of fresh-eating jujube in China.  Fruit texture is an important indicator of sensory quality.  To investigate the correlations among texture indices and establish an evaluation system for winter jujube texture, we used the TMS-Touch instrument to perform a texture profile analysis (TPA) on 1 150 winter jujubes from three major producing areas in China.  Eight indices and their best-fit distribution were obtained, including fracture (Pearson), hardness (InvGauss), adhesive force (Weibull), adhesiveness (LogLogistic), cohesiveness (LogLogistic), springiness (BetaGeneral), gumminess (InvGauss), and chewiness (InvGauss).  Based on the best-fit distribution curves, each index was divided into five grades (lower, low, medium, high and higher) by the 10th, 30th, 70th and 90th percentiles.  Among the texture indices, 82% of the correlation coefficients were highly significant (P<0.01); meanwhile, chewiness was significantly (P<0.01) and positively correlated with springiness and gumminess, of which the correlation coefficients were up to 0.8692 and 0.8096, respectively.  However, adhesiveness was significantly (P<0.01) and negatively related to adhesive force with a correlation coefficient of –0.7569.  Among hardness, cohesiveness, springiness, gumminess, and chewiness, each index could be well fitted by a multiple linear regression with the remaining four indices, with the coefficients above 0.94 and the mean fitting error and mean prediction error lower than 10%.  A comprehensive evaluation model was consequently established based on factor analysis to evaluate the texture quality of winter jujube.  The results demonstrated that winter jujube with higher comprehensive scores generally exhibited higher springiness and chewiness, but had lower adhesive force and adhesiveness.  We used factor analysis and clustering analysis to divide the eight studied texture into four groups (cohesive factor, adhesive-soft factor, tough-hard factor, and crispness factor), whose representative indices were springiness, adhesiveness, hardness, and fracture, respectively.  Overall, this study investigated the variation in each index of winter jujube texture, explored the association among these indices, screened the representative indices, and established a texture evaluation system.  The results provide a methodological basis and technical support for evaluating winter jujube texture.

    Changes in phenolic content, composition and antioxidant activity of blood oranges during cold and on-tree storage
    ZHAO Ji-chun, AO Miao, HE Xiao-qin, LI Wei-zhou, DENG Li-li, ZENG Kai-fang, MING Jian
    2022, 21(12): 3669-3683.  DOI: 10.1016/j.jia.2022.09.011
    Abstract ( )   PDF in ScienceDirect  
    Citrus fruits are rich in phenolic compounds that possess several health benefits.  However, few studies have focused on the changes in phenolic compounds in citrus fruits during postharvest storage.  This study dynamically monitored the phenolic content, components and antioxidant activity of ‘Tarocco’ blood oranges during a period of 12-week cold storage and on-tree storage, respectively.  We investigated the alteration mechanism of phenolic compounds in blood oranges by evaluating phenylpropanoid pathway-related enzyme activities and gene expression.  Results showed that flavanones were the main phenolic compounds in blood oranges.  Both storage methods mainly stimulated the accumulation of phenolic acids to improve total phenolic content, which reached the maximum at week 12.  Nonetheless, blood oranges had a higher phenolic content and antioxidant activity under on-tree storage than cold storage.  Furthermore, the enzyme activities and gene expression of the phenylpropanoid pathway demonstrated that the accumulation of phenolics in blood oranges during storage was highly related to the activation of the phenylpropanoid pathway.  These results demonstrate that on-tree storage is a potential approach for extending the supply period of blood orange from the perspective of phenolic compounds.
    Short Communication
    Neopestalotiopsis eucalypti, a causal agent of grapevine shoot rot in cutting nurseries in China
    MA Xuan-yan, JIAO Wei-qi, LI Heng, ZHANG Wei, REN Wei-chao, WU Yan, ZHANG Zhi-chang, LI Bao-hua, ZHOU Shan-yue
    2022, 21(12): 3684-3691.  DOI: 10.1016/j.jia.2022.08.123
    Abstract ( )   PDF in ScienceDirect  
    Grapevine (Vitis vinifera L.) is an economically important fruit crop in the world, and China ranks first in the production of grapes with approximately 15% of the world’s total yield.  However, diseases that cause the death of grapevine shoots pose a severe threat to the production of grapes.  In this study, the fungus Neopestalotiopsis eucalypti was identified as a causal pathogen of grapevine shoot rot based on the morphology of conidia and a phylogenetic analysis.  The phylogenetic analysis was performed with three isolates based on the combined sequence of internal transcribed spacer (ITS) region of ribosomal DNA, part of the translation elongation factor 1-alpha (Tef) and the β-tubulin (Tub2) genes.  The three isolates were all identified as N. eucalypti.  Pathogenicity tests of the three fungal isolates were conducted on grapevines shoots in vitro and in vivo.  The results showed that all three fungal isolates caused severe rot lesions on the inoculated grapevine shoots, and N. eucalypti was re-isolated from the inoculated grapevine shoots.  Therefore, N. eucalypti was confirmed as a causal agent of the grapevine shoot rot.  This is the first report of N. eucalypti causing grapevine shoot disease in China.