The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical fertilizers. Critical nutrient values can be used for evaluating the nutritional status of a crop, and they reflect the nutrient concentrations above which the plant is sufficiently supplied for achieving the maximum potential yield. Based on on-farm surveys of 504 farmers and 60 field experimental sites in the drylands of China, we proposed a recommended fertilization method to determine nitrogen (N), phosphorus (P), and potassium (K) fertilizer input rates for wheat production, and then validated the method by a field experiment at 66 different sites in northern China. The results showed that wheat grain yield varied from 1.1 to 9.2 t ha⁻¹, averaging 4.6 t ha⁻¹, and it had a quadratic relationship with the topsoil (0−20 cm) nitrate N and soil available P contents at harvest. However, yield was not correlated with the inputs of N, P, and K fertilizers. Based on the relationship (exponential decay model) between 95–105% of the relative yield and topsoil nitrate N, available P, and available K contents at wheat harvest from 60 field experiments, the topsoil critical nutrient values were determined as 34.6, 15.6, and 150 mg kg⁻¹ for soil nitrate N, available P, and available K, respectively. Then, based on five groups of relative yield (>125%, 115–125%, 105–115%, 95–105%, and <95%) and the model, the five groups of topsoil critical nutrient levels and fertilization coefficients (Fc) were determined. Finally, we proposed a new method for calculating the recommended fertilizer input rate as: Fr=Gy×Nr×Fc, where Fr is the recommended fertilizer (N/P/K) input rate; Gy is the potential grain yield; Nr is the N(N_rN), P(N_rP), and K(N_rK) nutrient requirements for wheat to produce 1,000 kg of grain; and Fc is a coefficient for N(N_c)/P(P_c)/K(K_c) fertilizer. A 2-year validated experiment confirmed that the new method reduced N fertilizer input by 17.5% (38.5 kg N ha⁻¹) and P fertilizer input by 43.5% (57.5 kg P₂O₅ ha⁻¹) in northern China and did not reduce the wheat yield. This outcome can significantly increase the farmers’ benefits (by 7.58%, or 139 US$ ha⁻¹).  Therefore, this new recommended fertilization method can be used as a tool to guide N, P, and K fertilizer application rates for dryland wheat production.

Mikania micrantha is a fast-growing global invasive weed species that causes severe damage to natural ecosystems and very large economic losses of forest and crop production.  It has advantages in photosynthesis, including a similar net photosynthetic rate as C₄ plants and a higher carbon fixation capacity.  We used a combination of genomics and transcriptomics approaches to study the evolutionary mechanisms and circadian expression patterns of M. micrantha.  In M. micrantha, 16 positive selection genes focused on photoreaction and utilization of photoassimilates.  In different tissues, 98.1% of the genes associated with photoresponse had high expression in stems, and more than half of the genes of the C₄ cycle had higher expression in stems than in leaves.  In stomatal opening and closing, 2 genes of carbonic anhydrase (CAs) had higher expression at 18:00 than at 8:00, and the slow anion channel 1 (SLAC1) and high-leaf-temperature 1 kinase (HT1) genes were expressed at low levels at 18:00.  In addition, genes associated with photosynthesis had higher expression levels at 7:00 and 17:00.  We hypothesized that M. micrantha may undergo photosynthesis in the stem and flower organs and that some stomata of the leaves were opening at night by CO₂ signals.  In addition, its evolution may attenuate photoinhibition at high light intensities, and enhance more efficient of photosynthesis during low light intensity.  And the tissue-specific photosynthetic types and different diurnal pattern of photosynthetic-related genes may contribute to its rapid colonization of new habitats of M. micrantha.

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield, soil carbon storage, and nutrient use efficiency.  However, how the long-term substitution of chemical fertilizer with organic manure affects rice yield, carbon sequestration rate (CSR), and nitrogen use efficiency (NUE) while ensuring environmental safety remains unclear.  This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield, CSR, and NUE.  It also determined the optimum substitution ratio in the acidic soil of southern China.  The treatments were: (i) NPK₀, unfertilized control; (ii) NPK₁, 100% chemical nitrogen, phosphorus, and potassium fertilizer; (iii) NPKM₁, 70% chemical NPK fertilizer and 30% organic manure; (iv) NPKM₂, 50% chemical NPK fertilizer and 50% organic manure; and (v) NPKM₃, 30% chemical NPK fertilizer and 70% organic manure.  Milk vetch and pig manure were sources of manure for early and late rice seasons, respectively.  The result showed that SOC content was higher in NPKM₁, NPKM₂, and NPKM₃ treatments than in NPK₀ and NPK₁ treatments.  The carbon sequestration rate increased by 140, 160, and 280% under NPKM₁, NPKM₂, and NPKM₃ treatments, respectively, compared to NPK₁ treatment.  Grain yield was 86.1, 93.1, 93.6, and 96.5% higher under NPK₁, NPKM₁, NPKM₂, and NPKM₃ treatments, respectively, compared to NPK₀ treatment.  The NUE in NPKM₁, NPKM₂, and NPKM₃ treatments was higher as compared to NPK₁ treatment for both rice seasons.  Redundancy analysis revealed close positive relationships of CSR with C input, total N, soil C:N ratio, catalase, and humic acids, whereas NUE was closely related to grain yield, grain N content, and phenol oxidase.  Furthermore, CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.  The technique for order of preference by similarity to ideal solution (TOPSIS) showed that NPKM₃ treatment was the optimum strategy for improving CSR and NUE.  Therefore, substituting 70% of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China

Porcine proliferative enteropathy (PPE), an important infectious disease in pig production caused by an obligate intracellular bacterium Lawsonia intracellularis, is commonly associated with diarrhea and reduced weight gain in growing pigs widespread.  An accurate method for detecting L. intracellularis is particularly important for preventing and controlling PPE.  Heat shock protein 60 (Hsp60) is an immunodominant bacterial antigen found in all eukaryotic and prokaryotic organisms.  Thus, the purpose of the current investigation was to produce a novel L. intracellularis Hsp60 monoclonal antibody (mAb) useful for immunodiagnostics.  Three hybridomas secreted anti-Hsp60 termed 3E5, 4E2, and 9G6 were generated, and the titers of ascitic fluids of 3E5, 4E2, 9G6 were 1:1 024 000, 1:2 048 000 and 1:2 048 000, respectively.  The Western blotting analysis demonstrated that recombinant Hsp60 (rHsp60) was recognized by mAbs 3E5, 4E2 and 9G6.  Subsequently, analyses of specificity showed all the mAbs were highly specific to L. intracellularis while could not significantly react with other enteric bacteria commonly found in the ileum of pigs, such as Escherichia coli, Salmonella Choleraesuis, Salmonella Typhimurium, and Brachyspira hyodysenteriae.  Furthermore, the mAbs were useful for detecting L. intracellularis in the infected monolayer cells and histological sections of the ileum from PPE-affected pigs.  Our research will provide a foundation for the development of immunological diagnostic tests

Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.  This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.  Genotype, planting year, accession type, seed cotyledon color, and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.  The mean total carotenoid content was in the range of 8.15–14.72 µg g^–1 across the ecoregions.  The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.  Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.  Remarkably, lutein was the most abundant carotenoid in all the germplasms, ranging from 1.35–37.44 µg g^–1.  Carotenoids and chlorophylls showed significant correlations with other quality traits, which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.  Collectively, our results demonstrate that carotenoids are adequately accumulated in soybean seeds, however, they are strongly influenced by genetic factors, accession type, and germplasm origin.  We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs, and thereby as the raw materials for food sectors, pharmaceuticals, and the cosmetic industry.

Anthocyanin is an important pigment that affects plant color and nutritional quality.  MYBs play an important role in plant anthocyanin synthesis and accumulation.  However, the regulatory function of MYB transcription factors in anthocyanin synthesis in flax flowers is still unclear.  In this study, 402 MYB transcription factors were identified in the flax genome.  These MYB members are unevenly distributed on 15 chromosomes.  The R2R3-LuMYB members were divided into 32 phylogenetic subfamilies.  qRT-PCR analysis showed that seven R2R3-LuMYB genes in the adjacent subfamily of the evolutionary tree had similar expression patterns, among which LuMYB216 was highly expressed in the petals of different colors.  Moreover, gene editing of LuMYB216 in flax showed that the petal color, anther color and seed coat color of mutant plants were significantly lighter than those of wild-type plants, and the anthocyanin content of lumyb216 mutant plants was significantly reduced.  Correlation analysis indicated that LuMYB216 was significantly positively correlated with the upstream regulator bHLH30.  This study systematically analyzed the MYB gene family in flax, laying a foundation for studying the regulation of LuMYB216 in flax flower anthocyanin synthesis.

Maize tassel detection is essential for future agronomic management in maize planting and breeding, with application in yield estimation, growth monitoring, intelligent picking, and disease detection.  However, detecting maize tassels in the field poses prominent challenges as they are often obscured by widespread occlusions and differ in size and morphological color at different growth stages.  This study proposes the SEYOLOX-tiny Model that more accurately and robustly detects maize tassels in the field.  Firstly, the data acquisition method ensures the balance between the image quality and image acquisition efficiency and obtains maize tassel images from different periods to enrich the dataset by unmanned aerial vehicle (UAV).  Moreover, the robust detection network extends YOLOX by embedding an attention mechanism to realize the extraction of critical features and suppressing the noise caused by adverse factors (e.g., occlusions and overlaps), which could be more suitable and robust for operation in complex natural environments.  Experimental results verify the research hypothesis and show a mean average precision (mAP_@0.5) of 95.0%.  The mAP_@0.5, mAP_@0.5–0.95, mAP_{@0.5–0.95 (area=small)}, and mAP_{@0.5–0.95 (area=medium)} average values increased by 1.5, 1.8, 5.3, and 1.7%, respectively, compared to the original model.  The proposed method can effectively meet the precision and robustness requirements of the vision system in maize tassel detection.

Rye (Secale cereale L., 2n=2x=14, RR) is a significant genetic resource for improving common wheat because of its resistance to multiple diseases and abiotic-stress tolerant traits.  The 1RS chromosome from the German cultivated rye variety Petkus is critical in wheat breeding.  However, its weakened disease resistance highlights the need to identify new resources.  In the present study, a novel derived line called D27 was developed from common wheat and Mexico Rye.  Cytological observations characterized the karyotype of D27 as 2n=42=21 II.  Genomic in situ hybridization indicated that a pair of whole-arm translocated Mexico Rye chromosomes were inherited typically in the mitotic and meiosis stages of D27.  Experiments using fluorescence in situ hybridization (FISH) and gliadin electrophoresis showed that D27 lacked wheat 1DS chromosomes.  They were replaced by 1RS chromosomes of Mexico Rye, supported by wheat simple-sequence repeat markers, rye sequence characterized amplified region markers, and wheat 40K SNP array analysis.  The wheat 1DS chromosomes could not be detected by molecular markers and wheat SNP array, but the presence of rye 1RS chromosomes was confirmed.  Agronomic trait assessments indicated that D27 had a higher tiller number and enhanced stripe rust and powdery mildew resistance.  In addition, dough properties analysis showed that replacing 1DS led to higher viscosity and lower dough elasticity in D27, which was beneficial for cake making.  In conclusion, the novel cytogenetically stable common wheat–Mexico Rye T1DL·1RS translocation line D27 offers excellent potential as outstanding germplasm in wheat breeding programs focusing on disease resistance and yield improvement.  Additionally, it can be valuable for researching the rye 1RS chromosome’s genetic diversity. 

Aegilops umbellulata (UU) is a wheat wild relative that has potential use in the genetic improvement of wheat.  In this study, 46 Ae. umbellulata accessions were investigated for stripe rust resistance, heading date (HD), and the contents of iron (Fe), zinc (Zn), and seed gluten proteins.  Forty-two of the accessions were classified as resistant to stripe rust, while the other four accessions were classified as susceptible to stripe rust in four environments.  The average HD of Ae. umbellulata was significantly longer than that of three common wheat cultivars (180.9 d vs. 137.0 d), with the exception of PI226500 (138.9 d).  The Ae. umbellulata accessions also showed high variability in Fe (69.74–348.09 mg kg^–1) and Zn (49.83–101.65 mg kg^–1) contents. Three accessions (viz., PI542362, PI542363, and PI554399) showed relatively higher Fe (230.96–348.09 mg kg^–1) and Zn (92.46–101.65 mg kg^–1) contents than the others.  The Fe content of Ae. umbellulata was similar to those of Ae. comosa and Ae. markgrafii but higher than those of Ae. tauschii and common wheat.  Aegilops umbellulata showed a higher Zn content than Ae. tauschii, Ae. comosa, and common wheat, but a lower content than Ae. markgrafii.  Furthermore, Ae. umbellulata had the highest proportion of γ-gliadin among all the species investigated (Ae. umbellulata vs. other species=mean 72.11% vs. 49.37%; range: 55.33–86.99% vs. 29.60–67.91%).  These results demonstrated that Ae. umbellulata exhibits great diversity in the investigated traits, so it can provide a potential gene pool for the genetic improvement of these traits in wheat.

Caprine arthritis-encephalitis virus (CAEV) is an under-studied virus infecting caprines and ovines worldwide.  Over the last four decades, CAEV has spread in China, obtaining genomic data on CAEV strains circulating in China is of importance for developing diagnostic methods and eradicating associated diseases.  However, there is limited information on the genome, including characterizations, and the probable origin.  This work aimed to characterize Chinese CAEV genomes and population structures.  Five CAEV strains isolated from infected dairy goats between 1989 and 1994 in Gansu, Guizhou, Shaanxi, Shandong and Sichuan provinces were cloned and sequenced.  The Chinese CAEV had a 58–93% genome similarities to strains outside of China, and they belonged to subgenotype B1.  The highest similarity levels (98.3–99.3%) were with two other Chinese strains, and they shared a 91.8–92.3% similarity with the strain Clements (GenBank accession no. NC_001463.1) from outside of China.  The Chinese CAEV strains isolated from different provinces over five years were still highly homologous and contained unique ancestral population components, indicating that these Chinese strains had a common origin that differed from other known strains.  Our results provide genomic data on circulating Chinese CAEV strains and will be useful for future epidemiological investigations and CAEV eradication programs.

α-Linolenic acid (ALA, 18:3Δ9,12,15) is an essential fatty acid for humans since it is the precursor for the biosynthesis of omega-3 long-chain polyunsaturated fatty acids (LC-PUFA). Modern people generally suffer from deficiency of ALA because most staple food oils are low or lack ALA content. Biotechnological enrichment of ALA in staple oil crops is a promising strategy. Chia (Salvia hispanica) has the highest ALA content in its seed oil among known oil crops. In this study, the FAD2 and FAD3 genes from chia were engineered into a staple oil crop, oilseed rape (Brassica napus), via Agrobaterium tumefaciens-mediated transformation of their LP4-2A fusion gene construct driven by the seed-specific promoter PNapA. In seeds of T0, T1, and T2 lines, the average ALA contents were 20.86, 23.54, and 24.92%, respectively, which were 2.21, 2.68, and 3.03 folds of the non-transformed controls (9.42, 8.78, and 8.22%), respectively. The highest seed ALA levels of T0, T1, and T2 plants were 38.41, 35.98, and 39.19% respectively, which were 4.10–4.77 folds of the respective controls. FA-pathway enzyme genes (BnACCD, BnFATA, BnSAD, BnSCD, BnDGAT1, BnDGAT2, and BnDGAT3) and positive regulatory genes (BnWRI1, BnLEC1, BnL1L, BnLEC2, BnABI3, BnbZIP67, and BnMYB96) were all significantly up-regulated. In contrast, BnTT1, BnTT2, BnTT8, BnTT16, BnTTG1, and BnTTG2, encoding negative oil accumulation regulators but positive secondary metabolism regulators, were all significantly down-regulated. This means the foreign ShFAD2-ShFAD3 fusion gene, directly and indirectly, remodeled both positive and negative loci of the whole FA-related network in transgenic B. napus seeds.

Extreme low-temperature incidents have become more frequent and severe as climate change intensifies.  In Huang-Huai-Hai wheat growing area of China, the late spring coldness occurring at the jointing-booting stage (the anther interval stage) has resulted in significant yield losses of winter wheat.  This study attempts to develop an economical, feasible, and efficient cultivation technique for improving the low-temperature (LT) resistance of wheat by exploring the effects of twice-split phosphorus application (TSPA) on wheat antioxidant characteristics and carbon and nitrogen metabolism physiology under LT treatment at the anther interval stage using Yannong 19 as the experimental material.  The treatments consisted of traditional phosphorus application and TSPA, followed by a –4°C LT treatment and natural temperature (NT) control at the anther interval stage.  Our analyses showed that, compared with the traditional application, the TSPA increased the net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of leaves and reduced the intercellular carbon dioxide concentration (Ci).  The activity of carbon and nitrogen metabolism enzymes in the young wheat spikes was also increased by the TSPA, which promoted the accumulation of soluble sugar (SS), sucrose (SUC), soluble protein (SP), and proline (Pro) in young wheat spike and reduced the toxicity of malondialdehyde (MDA).  Due to the improved organic nutrition for reproductive development, the young wheat spikes exhibited enhanced LT resistance, which reduced the sterile spikelet number (SSN) per spike by 11.8% and increased the spikelet setting rate (SSR) and final yield by 6.0 and 8.4%, respectively, compared to the traditional application.  The positive effects of split phosphorus application became more pronounced when the LT treatment was prolonged.  

Increasing wheat yield is a long-term goal for wheat breeders around the world.  Exploiting elite genetic resources and dissecting the genetic basis of important agronomic traits in wheat are the necessary methods for high-yield wheat breeding.  This study evaluated nine crucial agronomic traits found in a natural population of 156 wheat varieties and 77 landraces from Sichuan, China in seven environments over two years.  The results of this investigation of agronomic traits showed that the landraces had more tillers and higher kernel numbers per spike (KNS), while the breeding varieties had higher thousand-kernel weight (TKW) and kernel weight per spike (KWS).  The generalized heritability (H²) values of the nine agronomic traits varied from 0.74 to 0.95.  Structure analysis suggested that the natural population could be divided into three groups using 43 198 single nucleotide polymorphism (SNP) markers from the wheat 55K SNP chip.  A total of 67 quantitative trait loci (QTLs) were identified by the genome-wide association study (GWAS) analysis based on the Q+K method of a mixed linear model.  Three important QTLs were analyzed in this study.  Four haplotypes of QFTN.sicau-7BL.1 for fertile tillers number (FTN), three haplotypes of QKNS.sicau-1AL.2 for KNS, and four haplotypes of QTKW.sicau-3BS.1 for TKW were detected.  FTN-Hap2, KNS-Hap1, and TKW-Hap2 were excellent haplotypes for each QTL based on the yield performance of 42 varieties in regional trials from 2002 to 2013.  The varieties with all three haplotypes showed the highest yield compared to those with either two haplotypes or one haplotype.  In addition, the KASP-AX-108866053 marker of QTL QKNS.sicau-1AL.2 was successfully distinguished between three haplotypes (or alleles) in 63 varieties based on the number of kernels per spike in regional trials between 2018 and 2021.  These genetic loci and reliable makers can be applied in marker-assisted selection or map-based gene cloning for the genetic improvement of wheat yield. 

The red coloring of pear fruits is mainly caused by anthocyanin accumulation.  Red sport, represented by the green pear cultivar ‘Bartlett’ (BL) and the red-skinned derivative ‘Max Red Bartlett’ (MRB), is an ideal material for studying the molecular mechanism of anthocyanin accumulation in pear.  Genetic analysis has previously revealed a quantitative trait locus (QTL) associated with red skin color in MRB.  However, the key gene in the QTL and the associated regulatory mechanism remain unknown.  In the present study, transcriptomic and methylomic analyses were performed using pear skin for comparisons between BL and MRB.  These analyses revealed differential PcHY5 DNA methylation levels between the two cultivars; MRB had lower PcHY5 methylation than BL during fruit development, and PcHY5 was more highly expressed in MRB than in BL.  These results indicated that PcHY5 is involved in the variations in skin color between BL and MRB.  We further used dual luciferase assays to verify that PcHY5 activates the promoters of the anthocyanin biosynthesis and transport genes PcUFGT, PcGST, PcMYB10 and PcMYB114, confirming that PcHY5 not only regulates anthocyanin biosynthesis but also anthocyanin transport.  Furthermore, we analyzed a key differentially methylated site between MRB and BL, and found that it was located in an intronic region of PcHY5.  The lower methylation levels in this PcHY5 intron in MRB were associated with red fruit color during development, whereas the higher methylation levels at the same site in BL were associated with green fruit color.  Based on the differential expression and methylation patterns in PcHY5 and gene functional verification, we hypothesize that PcHY5, which is regulated by methylation levels, affects anthocyanin biosynthesis and transport to cause the variations in skin color between BL and MRB.

Psathyrostachys huashanica Keng (2n=2x=14, NsNs) is regarded as a valuable wild relative species for common wheat cultivar improvement because of its abundant beneficial agronomic traits.  However, although the development of many wheat–P. huashanica-derived lines provides a germplasm base for the transfer of excellent traits, the lag in the identification of P. huashanica chromosomes in the wheat background has limited the study of these lines.  In this study, three novel nondenaturing fluorescence in situ hybridization (ND-FISH)-positive oligo probes were developed.  Among them, HS-TZ3 and HS-TZ4 could specifically hybridize with P. huashanica chromosomes, mainly in the telomere area, and HS-CHTZ5 could hybridize with the chromosomal centromere area.  We sequentially constructed a P. huashanica FISH karyotype and idiogram that helped identify the homologous groups of introduced P. huashanica chromosomes.  In detail, 1Ns and 2Ns had opposite signals on the short and long arms, 3Ns, 4Ns, and 7Ns had superposed two-color signals, 5Ns and 6Ns had fluorescent signals only on their short arms, and 7Ns had signals on the intercalary of the long arm.  In addition, we evaluated different ways to identify alien introgression lines by using low-density single nucleotide polymorphism (SNP) arrays and recommended the SNP homozygosity rate in each chromosome as a statistical pattern.  The 15K SNP array is widely applicable for addition, substitution, and translocation lines, and the 40K SNP array is the most accurate for recognizing transposed intervals between wheat and alien chromosomes.  Our research provided convenient methods to distinguish the homologous group of P. huashanica chromosomes in a common wheat background based on ND-FISH and SNP arrays, which is of great significance for efficiently identifying wheat–P. huashanica-derived lines and the further application of Ns chromosomes

Early defoliation, which usually occurs during summer in pear trees, is gradually becoming a major problem that poses a serious threat to the pear industry in southern China.  However, there is no system for evaluating the responses of different cultivars to early defoliation, and our knowledge of the potential molecular regulation of the genes underlying this phenomenon is still limited.  In this study, we conducted field investigations of 155 pear accessions to assess their resistance or susceptibility to early defoliation.  A total of 126 accessions were found to be susceptible to early defoliation, and only 29 accessions were resistant.  Among them, 19 resistant accessions belong to the sand pear species (Pyrus pyrifolia).  To identify the resistance genes related to early defoliation, the healthy and diseased samples of two sand pear accessions, namely, the resistant early defoliation accession ‘Whasan’ and the susceptible early defoliation accession ‘Cuiguan’, were used to perform RNA sequencing.  Compared with ‘Cuiguan’, a total of 444 genes were uniquely differentially expressed in ‘Whasan’.  Combined with GO and KEGG enrichment analyses, we found that early defoliation was closely related to the stress response.  Furthermore, a weighted gene co-expression network analysis revealed a high correlation of WRKY and ethylene responsive factor (ERF) transcription factors with early defoliation resistance.  This study provides useful resistant germplasm resources and new insights into potentially essential genes that respond to early defoliation in pears, which may facilitate a better understanding of the resistance mechanism and molecular breeding of resistant pear cultivars

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is an important insect pest of cotton crops worldwide.  The objectives of this study were to determine the acute toxicity of afidopyropen and whether there are any effects of sublethal concentrations of afidopyropen on the biological characteristics of A. gossypii.  The results showed that afidopyropen possesses high acute toxicity to adult A. gossypii with a 72 h LC₅₀ value of 1.062 mg L^–1.  A sublethal concentration (LC₁₀) of afidopyropen significantly decreased adult longevity, fecundity and oviposition days of female adults in both F₀ and F₁ generations.  The total pre-adult survival of F₁ progeny was also significantly reduced by 30% at the LC₁₀ of afidopyropen.  In addition, the nymph developmental time, pre-adult period, adult pre-reproductive period (APRP), and total pre-reproductive period (TPRP) of the F₁ progeny were significantly prolonged compared with the control.  Several population parameters, including the net reproductive rate (R₀), intrinsic rate of increase (r) and finite rate of increase (λ) of F₁ progeny were significantly decreased by a sublethal afidopyropen concentration exposure.  These results indicated that sublethal concentration of afidopyropen can significantly suppress A. gossypii population growth.  It would be useful for assessing the overall effects of afidopyropen on A. gossypii.  

Dwarfism is an important trait which is closely related to the efficiency of fruit orchard management and production.  However, dwarfing cannot be widely applied in the cultivation of pears, especially Asian pears.  Developing varieties with dwarf characteristics is a goal of paramount importance in pear breeding.  In the present study, dwarf phenotype pears (DPPs) and arborescent phenotype pears (APPs) were obtained from the offspring of a cross between ‘Aiyuxiang’ and ‘Cuiguan’ pear cultivars, which exhibited dwarfed and arborescent statures, respectively.  When compared with APPs, the heights of DPPs showed a 62.8% reduction, and the internode lengths were significantly shorter.  Cross-grafting between DPPs and APPs demonstrated that the dwarfed phenotype of DPPs was primarily induced by the aerial portions of the plant, and independent of the root system.  Observations of stem tissue sections showed that DPP cells were arranged chaotically with irregular shapes, and the average length was larger than that of the APP cells.  A total of 1 401 differently expressed genes (DEGs) in shoot apices between DPPs and APPs were identified by RNA-sequencing (RNA-Seq), and these DEGs were mainly enriched in the ‘phytohormone-related pathways, cell wall metabolism and cell division’ categories.  Moreover, 101 DEGs were identified as transcription factors (TFs).  In DPPs, several brassinosteroids (BR) signaling and cell cycle-related genes were significantly down-regulated, while genes involved in BR and GA degradation were up-regulated.  Comprehensive analysis of RNA-Seq data and stem tissue sections suggested that the dwarfed phenotype of DPPs could be primarily attributed to deficiencies in cell division.  Previous work using simple sequence repeat (SSR) markers narrowed the location of the gene responsible for the dwarf phenotype of ‘Le Nain Vert’.  Through combined analysis of our transcriptomic data with the SSR results, we identified four genes as promising candidates for the dwarf phenotype, among which, a DELLA gene could be the most promising.  The results presented in this study provide a sound foundation for further exploration into the genetic and molecular mechanisms underlying pear dwarfing.

This study evaluated the quality potential of seven synthetic hexaploid wheats (2n=6x=42, AABBDD) expressing only allelic variation at Glu-D1 of Aegilops tauschii (SHWSD).  Major quality parameters related to dough strength, gluten proteins (including high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS), gliadins), and their ratios between SHWSD and the weak gluten wheat control Chuannong 16 (CN16) were measured in at least three environments (except STD7).  The zeleny sedimentation value (ZSV), dough development time (DDT), dough stability time (DST), and farinograph quality number (FQN) of SHWSD were considered stable under different environments, with their respective ranges being 8.00–17.67 mL, 0.57–1.50 min, 0.73–1.80 min, and 9.50–27.00.  The ZSV, DDT, DST, and FQN of SHWSD were smaller than those of CN16, suggesting that SHWSD had a weaker dough strength than CN16.  Although SHWSD had a lower gluten index than CN16, its wet and dry gluten contents were similar to or even higher than those of CN16 in all environments tested.  The protein content of grains (12.81–18.21%) and flours (14.20–20.31%) in SHWSD was higher than that in CN16.  The amount of HMW-GS in SHWSD sharply decreased under the expression of fewer HMW-GS genes, and the LMW-GS, gliadins, and total glutenins were simultaneously increased in SHWSD in comparison with CN16.  Moreover, SHWSD had higher ratios of LMW-GS/glutenin and gliadin/glutenin but a lower ratio of HMW-GS/glutenin than CN16.  These results provide necessary information for the utilization of SHWSD in weak-gluten wheat breeding.

Excessive use of nitrogen fertilizer in China and its adverse effects on agricultural production have been a national and global concern. In addition to massive public initiatives to promote sustainable farm practices, grass-rooted innovations are emerging in the niche, many of which take the forms of information and communication technologies (ICT) and digital services. This study examines the effects of ICT-based extension services provided by an entrepreneurial startup on adopting sustainable farming practices. We found no significant reduction in N-fertilizer use for wheat production. But the ICT-based services promoted farmers to adapt N-fertilizer use towards site-specific management. The business model of the entrepreneurial venture faces great challenges in becoming participatory and financially sustainable.

Single-step genomic best linear unbiased prediction (ssGBLUP) is now intensively investigated and widely used in livestock breeding due to its beneficial feature of combining information from both genotyped and ungenotyped individuals in the single model.  With the increasing accessibility of whole-genome sequence (WGS) data at the population level, more attention is being paid to the usage of WGS data in ssGBLUP.  The predictive ability of ssGBLUP using WGS data might be improved by incorporating biological knowledge from public databases.  Thus, we extended ssGBLUP, incorporated genomic annotation information into the model, and evaluated them using a yellow-feathered chicken population as the examples.  The chicken population consisted of 1 338 birds with 23 traits, where imputed WGS data including 5 127 612 single nucleotide polymorphisms (SNPs) are available for 895 birds.  Considering different combinations of annotation information and models, original ssGBLUP, haplotype-based ssGHBLUP, and four extended ssGBLUP incorporating genomic annotation models were evaluated.  Based on the genomic annotation (GRCg6a) of chickens, 3 155 524 and 94 837 SNPs were mapped to genic and exonic regions, respectively.  Extended ssGBLUP using genic/exonic SNPs outperformed other models with respect to predictive ability in 15 out of 23 traits, and their advantages ranged from 2.5 to 6.1% compared with original ssGBLUP.  In addition, to further enhance the performance of genomic prediction with imputed WGS data, we investigated the genotyping strategies of reference population on ssGBLUP in the chicken population.  Comparing two strategies of individual selection for genotyping in the reference population, the strategy of evenly selection by family (SBF) performed slightly better than random selection in most situations.  Overall, we extended genomic prediction models that can comprehensively utilize WGS data and genomic annotation information in the framework of ssGBLUP, and validated the idea that properly handling the genomic annotation information and WGS data increased the predictive ability of ssGBLUP.  Moreover, while using WGS data, the genotyping strategy of maximizing the expected genetic relationship between the reference and candidate population could further improve the predictive ability of ssGBLUP.  The results from this study shed light on the comprehensive usage of genomic annotation information in WGS-based single-step genomic prediction.

Available irrigation resources are becoming increasingly scarce in the North China Plain (NCP), and nitrogen-use efficiency of crop production is also relatively low. Thus, it is imperative to improve the water-use efficiency (WUE) and nitrogen fertilizer productivity on the NCP. Here, we conducted a two-year field experiment to explore the effects of different irrigation amounts (S60, 60 mm; S90, 90 mm; S120, 120 mm; S150, 150 mm) and nitrogen application rates (150, 195 and 240 kg ha^–1; denoted as N1, N2 and N3, respectively) under micro-sprinkling with water and nitrogen combined on the grain yield (GY), yield components, leaf area index (LAI), flag leaf chlorophyll content, dry matter accumulation (DM), WUE, and nitrogen partial factor productivity (NPFP). The results indicated that the GY and NPFP increased significantly with increasing irrigation amount, but there was no significant difference between S120 and S150; WUE significantly increased first but then decreased with increasing irrigation and S120 achieved the highest WUE. The increase in nitrogen was beneficial to improving the GY and WUE in S60 and S90, while the excessive nitrogen application (N3) significantly reduced the GY and WUE in S120 and S150 compared with those in the N2 treatment. The NPFP significantly decreased with increasing nitrogen rate under the same irrigation treatments. The synchronous increase in spike number (SN) and 1 000-grain weight (TWG) was the main reason for the large increase in GY by micro-sprinkling with increasing irrigation, and the differences in SN and TGW between S120 and S150 were small. Under S60 and S90, the TGW increased with increasing nitrogen application, which enhanced the GY, while N2 achieved the highest TWG in S120 and S150. At the filling stage, the LAI increased with increasing irrigation, and greater amounts of irrigation significantly increased the chlorophyll content in the flag leaf, which was instrumental in increasing DM after anthesis and increasing the TGW. Micro-sprinkling with increased amounts of irrigation or excessive nitrogen application decreased the WUE mainly due to the increase in total water consumption (ET) and the small increase or decrease in GY. Moreover, the increase in irrigation increased the total nitrogen accumulation or contents (TNC) of plants at maturity and reduced the residual nitrate-nitrogen in the soil (SNC), which was conducive to the increase in NPFP, but there was no significant difference in TNC between S120 and S150. Under the same irrigation treatments, an increase in nitrogen application significantly increased the residual SNC and decreased the NPFP. Overall, micro-sprinkling with 120 mm of irrigation and a total nitrogen application of 195 kg ha–1 can lead to increases in GY, WUE and NPFP on the NCP.

Now, lodging is a major constraint factor contributing to yield loss of maize (Zea mays L.) under high planting density. Chemical regulation and nitrogen fertilizer could effectively coordinate the relationship between stem lodging and maize yield, which significantly reduce lodging and improve the grain yield. The purpose of this study was to explore the effects of chemical regulation and different nitrogen application rates on lodging characteristics, grain filling and yield of maize under high density. For this, we established a field study during 2017 and 2018 growing seasons, with three nitrogen levels of N100 (100 kg ha^–1), N200 (200 kg ha^–1) and N300 (300 kg ha^–1) at high planting density (90 000 plants ha^–1), and applied plant growth regulator (Yuhuangjin, the mixture of 3% DTA-6 and 27% ethephon) at the 7th leaf. The results showed that chemical control increased the activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), 4-coumarate:CoA ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD), and increased the lignin, cellulose and hemicellulose contents at the bottom of the 3rd internode, which significantly reduced the lodging percentage. The lignin-related enzyme activities, lignin, cellulose and hemicellulose contents decreased with the increase of nitrogen fertilizer, which significantly increased the lodging percentage. The 200 kg ha^–1 nitrogen application and chemical control increased the number, diameter, angle, volume, and dry weight of brace roots. The 200 kg ha^–1 nitrogen application and chemical control significantly increased the activities of ADP-glucose pyrophosphorylase (AGPase), soluble starch synthase (SSS) and starch branching enzyme (SBE), which promoted the starch accumulation in grains. Additional, improved the maximum grain filling rate (V_max) and mean grain filling rate (V_m), which promoted the grain filling process, significantly increased grain weight and grain number per ear, thus increased the final yield.