Accurate estimation of regional winter wheat yields is essential for understanding the food production status and ensuring national food security.  However, using the existing remote sensing-based crop yield models to accurately reproduce the inter-annual and spatial variations in winter wheat yields remains challenging due to the limited ability to acquire irrigation information in water-limited regions.  Thus, we proposed a new approach to approximating irrigations of winter wheat over the North China Plain (NCP), where irrigation occurs extensively during the winter wheat growing season.  This approach used irrigation pattern parameters (IPPs) to define the irrigation frequency and timing.  Then, they were incorporated into a newly-developed process-based and remote sensing-driven crop yield model for winter wheat (PRYM–Wheat), to improve the regional estimates of winter wheat over the NCP.  The IPPs were determined using statistical yield data of reference years (2010–2015) over the NCP.  Our findings showed that PRYM–Wheat with the optimal IPPs could improve the regional estimate of winter wheat yield, with an increase and decrease in the correlation coefficient (R) and root mean square error (RMSE) of 0.15 (about 37%) and 0.90 t ha^–1 (about 41%), respectively.  The data in validation years (2001–2009 and 2016–2019) were used to validate PRYM–Wheat.  In addition, our findings also showed R (RMSE) of 0.80 (0.62 t ha^–1) on a site level, 0.61 (0.91 t ha^–1) for Hebei Province on a county level, 0.73 (0.97 t ha^–1) for Henan Province on a county level, and 0.55 (0.75 t ha^–1) for Shandong Province on a city level.  Overall, PRYM–Wheat can offer a stable and robust approach to estimating regional winter wheat yield across multiple years, providing a scientific basis for ensuring regional food security.

Soil salinization is a critical environmental issue restricting agricultural production.  Deep return of straw to the soil as an interlayer (at 40 cm depth) has been a popular practice to alleviate salt stress.  However, the legacy effects of straw added as an interlayer at different rates on soil organic carbon (SOC) and total nitrogen (TN) in saline soils still remain inconclusive.  Therefore, a four-year (2015–2018) field experiment was conducted with four levels (i.e., 0, 6, 12 and 18 Mg ha^–1) of straw returned as an interlayer.  Compared with no straw interlayer (CK), straw addition increased SOC concentration by 14–32 and 11–57% in the 20–40 and 40–60 cm soil layers, respectively.  The increases in soil TN concentration (8–22 and 6–34% in the 20–40 and 40–60 cm soil layers, respectively) were lower than that for SOC concentration, which led to increased soil C:N ratio in the 20–60 cm soil depth.  Increases in SOC and TN concentrations in the 20–60 cm soil layer with straw addition led to a decrease in stratification ratios (0–20 cm:20–60 cm), which promoted uniform distributions of SOC and TN in the soil profile.  Increases in SOC and TN concentrations were associated with soil salinity and moisture regulation and improved sunflower yield.  Generally, compared with other treatments, the application of 12 Mg ha^–1 straw had higher SOC, TN and C:N ratio, and lower soil stratification ratio in the 2015–2017 period.  The results highlighted that legacy effects of straw application as an interlayer were maintained for at least four years, and demonstrated that deep soil straw application had a great potential for improving subsoil fertility in salt-affected soils.

Lignin metabolism plays a pivotal role in plant defense against pathogens and is always positively correlated as a response to pathogen infection.  Thus, understanding resistance genes against pathogens in plants depends on a genetic analysis of lignin response.  In the study, eight upland cotton lines were used to construct a multi-parent advanced generation intercross (MAGIC) population (n=280), which exhibited peculiar characteristics from the convergence of various alleles coding for advantageous traits.  To measure the lignin response to Verticillium wilt (LRVW), artificial disease nursery (ADN) and rotation nursery (RN) were prepared for MAGIC population planting in four environments.  The stem lignin contents were collected, and the LRVW was measured with the lignin value of ADN/RN in each environment, which showed great variation.  A total of 9323 high-quality single-nucleotide polymorphism (SNP) markers obtained from the Cotton-SNP63K array were employed for genotyping the MAGIC population.  The SNPs were distributed through the whole genome with 4.78 SNP/Mb density, ranging from 1.14 (ChrA06) to 10.08 (ChrD08).  A genome-wide association study was performed using a mixed linear model (MLM) for LRVW, and three stable quantitative trait loci (QTLs), qLRVW-A04, qLRVW-A10 and qLRVW-D05, were identified in more than two environments.  Two key candidate genes, Ghi_D05G01046 and Ghi_D05G01221, were selected within the QTLs through the combination of variations in the coding sequence, induced expression patterns, and function annotations, both of which presented nonsynonymous mutations in coding regions and were strongly induced by Verticillium dahliae. Ghi_D05G01046 encodes a leucine-rich extensin (LRx) protein, which is involved in Arabidopsis cell wall biosynthesis and organization.  Ghi_D05G01221 encodes a transcriptional co-repressor novel interactor of jaz (NINJA), which functions in the jasmonic acid (JA) signaling pathway.  In summary, the study creates valuable genetic resources for breeding and QTL mapping and opens up a new perspective to uncover the genetic basis of VW resistance in upland cotton.

The fully mulched ridge–furrow (FMRF) system has been widely used on the semi-arid Loess Plateau of China due to its high maize (Zea mays L.) productivity and rainfall use efficiency.  However, high outputs under this system led to a depletion of soil moisture and soil nutrients, which reduces its sustainability in the long run.  Therefore, it is necessary to optimize the system for the sustainable development of agriculture.  The development, yield-increasing mechanisms, negative impacts, optimization, and their relations in the FMRF system are reviewed in this paper.  We suggest using grain and forage maize varieties instead of regular maize; mulching plastic film in autumn or leaving the mulch after maize harvesting until the next spring, and then removing the old film and mulching new film; combining reduced/no-tillage with straw return; utilizing crop rotation or intercropping with winter canola (Brassica campestris L.), millet (Setaria italica), or oilseed flax (Linum usitatissimum L.); reducing nitrogen fertilizer and partially replacing chemical fertilizer with organic fertilizer; using biodegradable or weather-resistant film; and implementing mechanized production.  These integrations help to establish an environmentally friendly, high quality, and sustainable agricultural system, promote high-quality development of dryland farming, and create new opportunities for agricultural development in the semi-arid Loess Plateau.

Lysophosphatidic acid (LPA) is a small molecule glycerophospholipid, which regulates multiple downstream signalling pathways through G-protein-coupled receptors to achieve numerous functions on oocyte maturation and embryo development.  In this study, sheep in vitro fertilized embryos were applied to investigate the effects of LPA on early embryos development and embryonic stem cell establishment.  At first, the maturation medium containing estrus female sheep serum and synthetic oviduct fluid (SOF) were optimized for sheep IVF, and then the effects of LPA were investigated.  From 0.1 to 10 μmol L^–1, LPA had no significant effect on the cleavage rate (P>0.05), but the maturation rate and blastocyst rate increased dependently with LPA concentration (P<0.05), and the blastocyst morphology was normal.  When the LPA concentration was 15 μmol L^–1, the maturation rate, cleavage rate and blastocyst rate decreased significantly (P<0.05), and the blastocyst exhibited abnormal morphology and could not develop into high-quality blastocyst.  Besides, the exogenous LPA increases the expression of LPAR2, LPAR4, TE-related gene CDX-2

and pluripotency-related gene OCT-4 in sheep early IVF embryos with the raise of LPA concentration from 0.1 to 10 μmol

L^–1.  The expression of LPAR2, LPAR4, CDX-2 and OCT-4 from the LPA-0.1 μmol L^–1 to LPA-10 μmol L^–1 groups in early embryos were extremely significant (P<0.05), while the expression of these genes significantly decreased in 15 μmol L^–1 LPA-treated embryos compared with LPA-10 μmol L^–1 group (P<0.05).  The inner cell mass in 15 μmol L^–1 LPA-treated embryos was also disturbed, and the blastocysts formation was abnormal.  Secondly, the sheep IVF blastocysts were applied to establish embryonic stem cells.  The results showed that LPA made the blastocyst inoculated cells grow towards TSC-like cells.  They enhanced the fluorescence intensity and mRNA abundance of OCT-4 and CDX-2 as the concentration increased from 0 to 10 μmol L^–1, while 15 μmol L^–1 LPA decreased OCT-4 and CDX-2 expression in the derived cells.  The expression of CDX-2 and OCT-4 in the blastocyst inoculated cells of LPA-1 μmol L^–1 group and LPA-10 μmol L^–1 group extremely significantly increased (P<0.05), but there was significant decrease in LPA-15 μmol L^–1 group compared with LPA-10 μmol L^–1 group (P<0.05).  Meanwhile, the protein expression of LPAR2 and LPAR4 remarkably increased after treatment of LPA at 10 μmol L^–1 concentration.  This study references the IVF embryo production and embryonic stem cell research of domestic animals. 

Laboratory mutants of Sclerotinia sclerotiorum (Lib) de Bary, resistant to boscalid, have been extensively characterized.  However, the resistance situation in the lettuce field remains largely elusive.  In this study, among the 172 S. sclerotiorum isolates collected from asparagus lettuce field in Jiangsu Province, China, 132 isolates (76.74%) exhibited low-level resistance to boscalid (Bos^LR), with a discriminatory dose of 5 μg mL^–1.  In comparison to the boscalid-sensitive (Bos^S) isolates, most Bos^LR isolates demonstrated a slightly superior biological fitness, as evidenced by data on mycelial growth, sclerotium production and pathogenicity.  Moreover, most Bos^LR isolates showed comparable levels of oxalic acid (OA) accumulation, increased exopolysaccharide (EPS) content and reduced membrane permeability when compared to the Bos^S isolates.  Nevertheless, their responses to distinct stress factors diverged significantly.  Furthermore, the effectiveness of boscalid in controlling Bos^LR isolates on radish was diminished compared to its efficacy on Bos^S isolates.  Genetic mutations were identified in the SDH genes of Bos^LR isolates, revealing the existence of three resistant genotypes: I (A11V at SDHB, SDHB^A11V), II (Q38R at SDHC, SDHC^Q38R) and III (SDHB^A11V+SDHC^Q38R).  Importantly, no cross-resistance was observed between boscalid and other fungicides such as thifluzamide, pydiflumetofen, fluazinam, or tebuconazole.  Our molecular docking analysis indicated that the docking total score (DTS) of the type I resistant isolates (1.3993) was lower than that of the sensitive isolates (1.7499), implying a reduced affinity between SDHB and boscalid as a potential mechanism underlying the boscalid resistance in S. sclerotiorum.  These findings contribute to an enhanced comprehension of boscalid’s mode of action and furnish valuable insights into the management of boscalid resistance.

Potato is one of the staple food crops in North China.  However, potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.  Increasing yield and water use efficiency (WUE) of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China.  However, the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region.  Based on meta-analysis of field experiments from the literature and model simulation, this study quantified the potential yields of potatoes without water and fertilizer limitation, and yield under irrigated and rainfed conditions, and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains (DH), the Foothills of Yanshan hilly (YH), the North foot of the Yinshan Mountains (YM), and the Loess Plateau (LP) in North China.  Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha^–1 for the YH region, 11.4 t ha^–1 for the YM region, 11.2 t ha^–1 for the DH region, and 10.7 t ha^–1 for the LP region, respectively.  Observed rainfed potato tuber dry weight yield accounted for 61, 30, 28 and 24% of the potential yield in the DH, YH, YM, and LP regions.  The maximum WUE of 2.2 kg m^–3 in the YH region, 2.1 kg m^–3 in the DH region, 1.9 kg m^–3 in the YM region and 1.9 kg m^–3 in the LP region was achieved under the potential yield level.  Ridge-furrow planting could boost yield by 8–49% and WUE by 2–36% while ridge-furrow planting with film mulching could boost yield by 35–89% and WUE by 7–57% across North China.  Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.

Understanding the spatial distribution of the crop yield gap (YG) is essential for improving crop yields.  Recent studies have typically focused on the site scale, which may lead to considerable uncertainties when scaled to the regional scale.  To mitigate this issue, this study used a process-based and remote sensing driven crop yield model for winter wheat (PRYM-Wheat), which was derived from the boreal ecosystem productivity simulator (BEPS), to simulate the YG of winter wheat in the North China Plain from 2015 to 2019.  Yield validation based on statistical yield data revealed good performance of the PRYM-Wheat Model in simulating winter wheat actual yield (Ya).  The distribution of Ya across the North China Plain showed great heterogeneity, decreasing from southeast to northwest.  The remote sensing-estimated results show that the average YG of the study area was 6 400.6 kg ha^–1.  The YG of Jiangsu Province was the largest, at 7 307.4 kg ha^–1, while the YG of Anhui Province was the smallest, at 5 842.1 kg ha^–1.  An analysis of the responses of YG to environmental factors showed no obvious correlation between YG and precipitation, but there was a weak negative correlation between YG and accumulated temperature.  In addition, the YG was positively correlated with elevation.  In general, studying the specific features of the YG can provide directions for increasing crop yields in the future

Follistatin (FST) is an important regulator of skeletal muscle growth and adipose deposition through its ability to bind to several members of the transforming growth factor-β (TGF-β) superfamily, and thus may be a good candidate for future animal breeding programs.  However, the molecular mechanisms underlying the phenotypic changes have yet to be clarified in pig.  We generated transgenic (TG) pigs that express human FST specifically in skeletal muscle tissues and characterized the phenotypic changes compared with the same tissues in wild-type pigs.  The TG pigs showed increased skeletal muscle growth, decreased adipose deposition, and improved metabolism status (P<0.05).  Transcriptome analysis detected important roles of the PIK3–AKT signaling pathway, calcium-mediated signaling pathway, and amino acid metabolism pathway in FST-induced skeletal muscle hypertrophy, and depot-specific oxidative metabolism changes in psoas major muscle.  Furthermore, the lipid metabolism-related process was changed in adipose tissue in the TG pigs.  Gene set enrichment analysis revealed that genes related to lipid synthesis, lipid catabolism, and lipid storage were down-regulated (P<0.01) in the TG pigs for subcutaneous fat, whereas genes related to lipid catabolism were significantly up-regulated (P<0.05) in the TG pigs for retroperitoneal fat compared with their expression levels in wild-type pigs.  In liver, genes related to the TGF-β signaling pathway were over-represented in the TG pigs, which is consistent with the inhibitory role of FST in regulating TGF-β signaling.  Together, these results provide new insights into the molecular mechanisms underlying the phenotypic changes in pig.

Soybean is one of the most important food crops worldwide.  Like other legumes, soybean can form symbiotic relationships with Rhizobium species.  Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for sustainable agriculture.  Type III effectors (T3Es) are essential regulators of the establishment of the symbiosis, and nodule number is a feature of nitrogen-affected nodulation.  However, genes encoding T3Es at quantitative trait loci (QTLs) related to nodulation have rarely been identified. Chromosome segment substitution lines (CSSLs) have a common genetic background but only a few loci with heterogeneous genetic information; thus, they are suitable materials for identifying candidate genes at a target locus.  In this study, a CSSL population was used to identify the QTLs related to nodule number in soybean.  Single nucleotide polymorphism (SNP) markers and candidate genes within the QTLs interval were detected, and it was determined which genes showed differential expression between isolines.  Four candidate genes (GmCDPK28, GmNAC1, GmbHLH, and GmERF5) linked to the SNPs were identified as being related to nodule traits and pivotal processes and pathways involved in symbiosis establishment.  A candidate gene (GmERF5) encoding a transcription factor that may interact directly with the T3E NopAA was identified.  The confirmed CSSLs with important segments and candidate genes identified in this study are valuable resources for further studies on the genetic network and T3Es involved in the signaling pathway that is essential for symbiosis establishment. 

Soil microbial biomass nitrogen (MBN) contains the largest proportion of biologically active nitrogen (N) in soil, and is considered as a crucial participant in soil N cycling.  Agronomic management practices such as crop rotation and mono-cropping systems, dramatically affect MBN in agroecosystems.  However, the influence of crop rotation and mono-cropping in agroecosystems on MBN remains unclear.  A meta-analysis based on 203 published studies was conducted to quantify the effect of crop rotation and mono-cropping systems on MBN under synthetic N fertilizer application.  The analysis showed that crop rotation significantly stimulated the response ratio (RR) of MBN to N fertilization and this parameter reached the highest levels in upland-fallow rotations.  Upland mono-cropping did not change the RR of MBN to N application, however, the RR of MBN to N application in paddy mono-cropping increased.  The difference between crop rotation and mono-cropping systems appeared to be due to the various cropping management scenarios, and the pattern, rate and duration of N addition.  Crop rotation systems led to a more positive effect on soil total N (TN) and a smaller reduction in soil pH than mono-cropping systems.  The RR of MBN to N application was positively correlated with the RR of mineral N only in crop rotation systems and with the RR of soil pH only in mono-cropping systems.  Combining the results of Random Forest (RF) model and structural equation model showed that the predominant driving factors of MBN changes in crop rotation systems were soil mineral N and TN, while in mono-cropping systems the main driving factor was soil pH.  Overall, our study indicates that crop rotation can be an effective way to enhance MBN by improving soil N resources, which promote the resistance of MBN to low pH induced by intensive synthetic N fertilizer application.

Flupyradifurone is a promising new insecticide used for controlling Bemisia tabaci during vegetable production.  In this study, we assessed the fitness costs and mode of inheritance associated with resistance to flupyradifurone in B. tabaci by comparing the susceptible strain (MED-S) to one field-evolved flupyradifurone-resistant strain (WH-R, with 199-fold resistance) and one laboratory-selected flupyradifurone-resistant strain (FLU-SEL, with 124-fold resistance).  Progenies of reciprocal crosses between WH-R and MED-S (F_1A, F_1B, and pooled F₁), and between FLU-SEL and MED-S (F_1C, F_1D, and pooled F₁’), showed varying degrees of dominance, indicating that resistance to flupyradifurone in WH-R was autosomal and incompletely dominant, yet in FLU-SEL it was autosomal and incompletely recessive.  Furthermore, the development of resistance to flupyradifurone occurred at the expense of fitness costs for the resistant populations.  Compared to the MED-S strain, WH-R showed a relative fitness of 0.50 with significantly prolonged developmental durations and reduced survival rates of the nymphal and pseudopupal stages, as well as decreased fecundity and hatchability.  Similarly, FLU-SEL showed a relative fitness of 0.65 and also demonstrated prolonged developmental durations and reduced survival rates of nymphs and pseudopupae, as well as decreased hatchability in comparison with the MED-S strain.  However, no significant differences in fecundity were observed between MED-S and FLU-SEL.  The present study provides useful knowledge for formulating pest management strategies in the field, which will allow growers to slow the development of resistance to flupyradifurone and to sustainably control B. tabaci.

The rice–crayfish farming model has been rapidly developed and become an economically viable method to supply food in China in recent years.  However, its environmental and economic sustainability has not been thoroughly investigated.  This study uses a survey in 2016 and a field experiment in 2017 in Qianjiang, Hubei Province, China to assess the relative economics of concurrent rice–wheat (RW), rice–crayfish (RC), and crayfish monoculture (CM) models in waterlogged land areas.  The field survey indicated that the RC model had a higher benefit–cost ratio (3.5:1) than the RW (2.0:1) and CM (3.1:1) models and the RC model protected farmers’ enthusiasm for grain production facing unfavourable weather conditions.  The field experiment aimed to explore nitrogen management strategies in RC fields.  In the experiment, four levels of nitrogen concentration gradient - 0 kg N ha^–1 (0 N), 75 kg N ha^–1 (75 N), 150 kg N ha^–1 (150 N) and 225 kg N ha^–1 (225 N), were set in a 2-year-old rice–crayfish (RC2) field, an 8-year-old rice–crayfish (RC8) field, and a RW field as a control.  The field experiment results suggested that the peak  rice yield in RW, RC2, and RC8 occurred when 225 N, 150 N and 75 N were used, respectively.  In RC2 and RC8, however, residual feed-nitrogen that was not used by crayfish was utilized by rice plants.  Thus, an optimal amount of nitrogen in RC fields was proposed to improve the nitrogen use efficiency and reduce environmental pollution by nitrogen fertilizer.  Farmers use less nitrogen but have higher net income in RC than in RW and CM.  It is necessary to sustainably develop integrated farming technologies (i.e., proper field configurations for rice fields) to effectively sustain rice production.  The results also showed that the RC farming model was a viable diversification option for rice farmers in waterlogged land.  

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a devastating disease of domestic and wild pigs.  There is no effective vaccine, and the control of the disease relies mainly on surveillance and early detection of infected pigs.  Previously, serological assays, such as ELISA, have been developed mainly based on recombinant structural viral proteins of ASFV, including p72, p54, and p30.  However, the antibodies against these proteins do not provide efficient protection against ASFV infection in pigs.  Therefore, new serological assays that can be applied for clinical diagnosis and evaluating serological immune response in vaccinated pigs are still required.  In this study, we expressed and purified a recombinant pB602L protein.  The purified pB602L protein was then used as an antigen to develop an indirect ELISA assay.  This assay has no cross-reaction with the anti-sera against the 15 most common pig pathogens in China, such as classical swine fever virus, pseudorabies virus, and porcine parvovirus.  This assay and a commercial ELISA kit were then used to detect 60 field pig serum samples, including an unknown number of anti-ASFV sera.  The coincidence of the two assays was 95%.  Furthermore, the pB602L-based ELISA was employed to test the antibody responses to the seven-gene-deleted ASFV strain HLJ/18-7GD in pigs.  The results showed that the antibody levels in all vaccinated pigs, starting from the 10th day post-inoculation, have increased continuously during the observation period of 45 days.  Our results indicate that this pB602L-based indirect ELISA assay can be employed potentially in the field of ASFV diagnosis.

Cotton is a globally important natural fiber and oilseed crop of crucial economic significance.  Molecular breeding has become a dominant method of cotton cultivation because it allows for a shorter breeding period and directional selection of high quality genes.  Patent data are key resources and are the core competitiveness of agricultural development, as the world’s largest and most reliable source of technical information.  However, little attention has been paid to patent analysis of cotton molecular breeding.  This study uses bibliometric analysis methodology and technical classification indexing to reveal global development trends of cotton molecular breeding, based on patents by retrieval methods and expert screening.  The annual number of patents, the life-cycle of patent-based technology, patent portfolios of primary countries, and main patentees, as well as technical distribution of patents, were analyzed in this study.  In addition, this study put emphasis on the comparative analysis of two important patentees through patent roadmaps based on the relationship among patent citations.  Finally, in order to understand the trend of new molecular breeding technology, patents related to clustered regularly interspaced short palindromic repeats (CRISPR), RNA interference (RNAi), and gene chip were also analyzed, all of which apply to cotton but also to other crops.  Results in this paper can provide references for cotton molecular breeding researchers and relevant management departments.

Black soil is one of the most precious soil resources on earth because it has abundant carbon stocks and a relatively high production capacity.  However, decreasing organic matter after land reclamation, and the effects of long-term inputs of organic carbon have made it less fertile black soil in Northeast China.  Straw return could be an effective method for improving soil organic carbon (SOC) sequestration in black soils.  The objective of this study was to evaluate whether straw return effectively increases SOC sequestration.  Long-term field experiments were conducted at three sites in Northeast China with varying latitudes and SOC densities.  Study plots were subjected to three treatments: no fertilization (CK); inorganic fertilization (NPK); and NPK plus straw return (NPKS).  The results showed that the SOC stocks resulting from NPKS treatment were 4.0 and 5.7% higher than those from NPK treatment at two sites, but straw return did not significantly affect the SOC stocks at the third site.  Furthermore, at higher SOC densities, the NPKS treatment resulted in significantly higher soil carbon sequestration rates (CSR) than the NPK treatment.  The equilibrium value of the CSR for the NPKS treatment equated to cultivation times of 17, 11, and 8 years at the different sites.  Straw return did not significantly increase the SOC stocks in regions with low SOC densities, but did enhance the C pool in regions with high SOC densities.  These results show that there is strong regional variation in the effects of straw return on the SOC stocks in black soil in Northeast China.  Additional cultivations and fertilization practices should be used when straw return is considered as an approach for the long-term improvement of the soil organic carbon pool.