Increasing the appropriate seedling density for higher yield in dry direct-seeded rice sown by a multifunctional seeder after wheatstraw return

Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maximum yield.Together,these results suggested that appropriately increasing the seedling density,and thereby increasing the proportion of panicles formed by the main stem,is an effective approach for obtaining a higher yield in DDR sown using a multifunctional seeder in a rice–wheat rotation system.

Genetic Diversity of Gli-1,Gli-2 and Glu-1 Alleles Among Chinese Endemic Wheats

Genetic diversity at Gli_1, Gli_2 and Glu_1 loci was investigated in 32 accessions of Chinese endemic wheat by using acid polyacrylamide gel electrophoresis (APAGE) and sodium dodecyl sulfate (SDS)_PAGE. There were 8 gliadin and 3 high_molecular_weight (HMW)_glutenin patterns in 14 Yunnan hulled wheat ( Triticum aestivum ssp. yunnanese King) accessions, 9 gliadin and 4 HMW_glutenin patterns in 9 Tibetan weedrace ( T. aestivum ssp. tibetanum Shao ) accessions, and 9 gliadin and 5 HMW_glutenin patterns in 9 Xinjiang rice wheat ( T. petropavlovskyi Udacz. et Migusch.) accessions. One accession (i.e. Daomai 2) carried new subunits 2.1+10.1 encoded by Glu_D1. Among the three Chinese endemic wheat groups, a total of 10, 14 and 11 alleles at Gli_1 locus; 11, 14 and 12 alleles at Gli_2 locus; and 5, 6 and 8 alleles at Glu_1 locus were identified, respectively. Among Yunnan hulled wheat, Tibetan weedrace and Xinjiang rice wheat, the Nei's genetic variation indexes were 0.3798, 0.5625 and 0.5693, respectively. These results suggested that Tibetan weedrace and Xinjiang rice wheat had higher genetic diversity than Yunnan hulled wheat.

Detection of Genetic Diversity in Synthetic Hexaploid Wheats Using Microsatellite Markers

Ninety-five synthetic hexaploid wheats （2n = 6x = 42, AABBDD） were analyzed using 45 microsatellite markers to investigate the potential genetic diversity in wheat breeding programs. A total of 326 alleles were detected by these microsatellite primer pairs, with an average of 6.65 alleles per locus. The polymorphic information content （PIC）, Simpson index （SI）, and genetic similarity （GS） coefficient showed that the D genome is of the highest genetic diversity among the A, B, and D genomes in the synthetic hexaploid wheats. The results also indicated that the synthetic hexaploid wheat is an efficient way to enrich wheat genetic backgrounds, especially to use the genetic variations of the D genome from Aegilops squarrosa for wheat improvement. The UPGMA dendogram, based on a similarity matrix by a simple matching coeff＇lcient algorithm, delineated the above accessions into 5 major clusters and was in accordance with the available pedigree information. The results demonstrated the utility of microsatellite markers in detecting DNA polymorphism and estimating genetic diversity.

Variations in the quality parameters and gluten proteins in synthetic hexaploid wheats solely expressing the Glu-D1 locus

This study evaluated the quality potential of seven synthetic hexaploid wheats(2 n=6 x=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 LMWGS/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.

Molecular Characterization and SNP Markers of the β-purothionin Gene in Einkorn Wheats

Forty-three gene sequences encoding purothionin were characterized from the three species or subspecies of einkorn wheats. These sequences contained 887 bp, among which 92 SNPs including 29 indel loci were detected, giving an average SNP frequency of one SNP per 9.64 bases. According to these sequences, 5 SNP markers were successfully designed, which were used to mine the variations ofpurothionin genes of 102 einkorn wheat accessions. Based on the 5 detected SNP loci, 102 einkorn wheat accessions could be divided into 21 haplotypes, among which 11 haplotypes contained a single sample. Phylogenetic analysis indicated that the purothionin genes from einkorn wheats were more closely related to those from D genome than B genome. Seven out of the 43 gene sequences were assumed to be pseudogenes by the definition of containing in-frame stop codons and small insertions/deletions leading to frameshift. In the remaining 36 amino acid sequences, the 8 Cys and Tyr-13 loci in the mature thionin domain which played important roles in the biological activities were all conserved, whereas there were some varieties occurred in some other important amino acid residues such as Lys and Arg.

Distribution of Grain Hardness in Chinese Wheats and Genetic Analysis

A hundred winter wheat and 41 spring wheat cultivars and advanced lines were used to investigate the distribution of grain hardness in Chinese wheats and correlations between grain hardness and other kernel traits. P1, P2, F1 , F2 and F3 from three crosses, i. e. , Liken2/Yumai2, 85Zhong33/Wenmai6 and 85Zhong33/95Zhong459 were sown to study the genetics of grain hardness. Significant correlation was observed between hardness measured by Single Kernel Characteristic System 4100 (SKCS 4100) and Near Infrared (NIR) Spectroscopy, r ranging from 0.85 to 0.94. Chinese wheat is a mixed population in terms of hardness, ranging from very soft to very hard. For autumn-sown wheat, on average, grain hardness decreases from north to south and spring-sown wheat is dominant with hard type. Hardness is negatively associated with flour color, and its associations with flour yield and ash content differ in winter and spring wheats. Grain hardness is controlled by a major gene and several minor genes with additive effect mostly, but dominant effect is also observed, with heritability of 0.78.

Comparison of Grain Zinc and Iron Concentration between Synthetic Hexaploid Wheats and Their Parents

Deficiencies of iron (Fe) and zinc (Zn) in human food afflict a large proportion of the world’s population. Wheat is a major food source of minerals. One way to enhance bread wheat’s ability to enrich these minerals would be to take advantage of diversity of wild species by creating synthetic hexaploid wheat (SW). In this study, two minerals (Fe and Zn) concentrated in the grain of Aegilops tauschii Coss. (2n = 2x = 14, DD), Triticum turgidum L. (2n = 4x = 28, AABB), and 33 lines of their corresponding SW (2n = 2x = 42, AABBDD) were evaluated. The results showed that Fe concentration was decreased in most of SW lines compared with their parental Aegilops tauschii accessions, while Zn concentration was greatly increased in most of SW lines compared with their parental Aegilops tauschii accessions. Aegilops tauschii had stronger Fe enrichment than Triticum turgidum while they expressed the same ability for Zn enrichment. The genotypic variance based on their physiological performance was analyzed. SW lines showed less genotypic variance of Fe and Zn concentration than Aegilops tauschii. SW lines showed less genotypic variance of Fe concentration than Triticum turgidum L. lines while they had more genotypic variance of Zn concentration than Triticum turgidum L. lines. Regardless of the fact that the traits expressed in wild relatives of wheat may not predict the traits that will be expressed in SW lines derived from them, production of SW could be a powerful method creating genotypes with enhanced trait expression.

Necrotic Incompatibility in Crosses of Bread Wheats in Argentina

Abstract： Synthetic wheats are the product of the cross between Triticum turgidum L. var. durum and T. tauschii. The 7＇. tauschii has shown excellent resistance to diseases, salinity, and drought, However, these synthetic wheats are also carriers of genes that produce varying degrees of necrosis, which is expressed as death of tissues in the hybrids （F l） generated from crosses with other bread wheats Necrotic incompatibility is a gradual premature leaf death in certain bread wheat F1 plants and it is caused by the interaction of two genes Nel and Ne2. In this paper 40 hybridizations with T. tauschii in the genetic constitution of some of the two parents made in 2006 and 2007 are presented, and their respective F1 planted at the CEI Barrow （Chacra Experimental de Barrow）. The plants that showed necrotic incompatibility had less growth than the normal F1 at tillering. Symptoms appeared at the beginning of tillering, remaining in that state and till jointing but they never headed. Out of the 16 Argentinean commercial cultivars evaluated, seven had the Ne allele in its genetic constitution and therefore showed necrotic incompatibility, whereas nine of them did not have the NE allele and their F 1 developed normally.

Winter wheat yield improvement by genetic gain across different provinces in China

The replacement of winter wheat varieties has contributed significantly to yield improvement worldwide,with remarkable progress in China.Drawing on two sets of data,production yield from the National Bureau of Statistics of China and experimental yield from literature,this study aims to(1)illustrate the increasing patterns of production yield among different provinces from 1978 to 2018 in China,(2)explore the genetic gain in yield and yield relevant traits through the variety replacement based on experimental yield from 1937 to 2016 in China,and(3)compare the yield gap between experimental yield and production yield.The results show that both the production and experimental yields significantly increased along with the variety replacement.The national annual yield increase ratio for the production yield was 1.67%from 1978 to 2018,varying from 0.96%in Sichuan Province to 2.78%in Hebei Province;such ratio for the experimental yield was 1.13%from 1937 to 2016.The yield gap between experimental and production yields decreased from the 1970s to the 2010s.This study reveals significant increases in some yield components consequent to variety replacement,including thousand-grain weight,kernel number per spike,and grain number per square meter;however,no change is shown in spike number per square meter.The biomass and harvest index consistently and significantly increased,whereas the plant height decreased significantly.

WPA1 encodes a vWA domain protein that regulates wheat plant architecture

Plant height,spike,leaf,stem and grain morphologies are key components of plant architecture and related to wheat yield.A wheat(Triticum aestivum L.)mutant,wpa1,displaying temperaturedependent pleiotropic developmental anomalies,was isolated.The WPA1 gene,encoding a von Willebrand factor type A(vWA)domain protein,was located on chromosome arm 7DS and isolated by map-based cloning.The functionality of WPA1 was validated by multiple independent EMS-induced mutants and gene editing.Phylogenetic analysis revealed that WPA1 is monocotyledon-specific in higher plants.The identification of WPA1 provides opportunity to study the temperature regulated wheat development and grain yield.

The first factor affecting dryland winter wheat grain yield under various mulching measures: Spike number

Water is the key factor limiting dryland wheat grain yield.Mulching affects crop yield and yield components by affecting soil moisture.Further research is needed to determine the relationships between yield components and soil moisture with yield,and to identify the most important factor affecting grain yield under various mulching measures.A long-term 9-yearifeld experiment in the Loess Plateau of Northwest China was carried out with three treatments:no mulch (CK),plastic mulch (M_(P)) and straw mulch (M_(S)).Yield factors and soil moisture were measured,and the relationships between them were explored by correlation analysis,structural equation modeling and significance analysis.The results showed that compared with CK,the average grain yields of M_(P) and M_(S) increased by 13.0and 10.6%,respectively.The average annual grain yield of the M_(P) treatment was 134 kg ha^(–1) higher than the M_(S) treatment.There were no significant differences in yield components among the three treatments (P<0.05).Soil water storage of the M_(S) treatment was greater than the M_(P) treatment,although the differences were not statistically signifiant.Soil water storage during the summer fallow period (SWSSF) and soil water storage before sowing (SWSS) of M_(S) were significantly higher than in CK,which increased by 38.5 and 13.6%,respectively.The relationship between M_(P) and CK was not statistically significant for SWSSF,but the SWSS in M_(P) was significantly higher than in CK.In terms of soil water storage after harvest (SWSH) and water consumption in the growth period(ET),there were no signi?cant differences among the three treatments.Based on the three analysis methods,we found that spike number and ET were positively correlated with grain yield.However,the relative importance of spike number to yield was the greatest in the M_(P )and M_(S) treatments,while that of ET was the greatest in CK.Suifcient SWSSF could indirectly increase spike number and ET in the three treatments.Based on these results,mulch can improve yield and soil water storage.The most important factor affecting the grain yield of dryland wheat was spike number under mulching,and ET with CK.These findings may help us to understand the main factors influencing dryland wheat grain yield under mulching conditions compared to CK.

A novel AgNPs/MOF substrate-based SERS sensor for high-sensitive on-site detection of wheat gluten

Gluten,known as the major allergen in wheat,has gained increasing concerns in industrialized countries,resulting in an urgent need for accurate,high-sensitive,and on-site detection of wheat gluten in complex food systems.Herein,we proposed a silver nanoparticles(AgNPs)/metal-organic framework(MOF)substrate-based surface-enhanced Raman scattering(SERS)sensor for the high-sensitive on-site detection of wheat gluten.The detection occurred on the newly in-situ synthesized AgNPs/MOF-modified SERS substrate,providing an enhancement factor(EF)of 1.89×10^(5).Benefitting from the signal amplification function of AgNPs/MOF and the superiority of SERS,this sensor represented high sensitivity performance and a wide detection range from 1×10^(-15)mol/L to 2×10^(-6)mol/L with a detection limit of 1.16×10^(-16)mol/L,which allowed monitoring the trace of wheat gluten in complex food system without matrix interference.This reliable sandwich SERS sensor may provide a promising platform for high-sensitive,accurate,and on-site detection of allergens in the field of food safety.

Spectral purification improves monitoring accuracy of the comprehensive growth evaluation index for film-mulched winter wheat

In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching,ridge–furrow full mulching, and flat cropping full mulching in winter wheat.Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV.Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks(ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out.The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status.The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75,a root mean square error of 8.40, and a mean absolute value error of 6.53.Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remotesensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification.The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching.

Subsoil tillage enhances wheat productivity,soil organic carbon and available nutrient status in dryland fields

Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.

Polyethylene glycol fusion repair of severed rat sciatic nerves reestablishes axonal continuity and reorganizes sensory terminal fields in the spinal cord

Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves.We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor recovery.Furthermore,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles.In this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve.Young adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of PEG.Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site.The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively.At 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase.PEG-fusion repair reestablished axonal continuity.Compared to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal areas.Unexpectedly,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair.This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair,supporting the use of this novel repair methodology over currently available treatments.

Involvement of the ABA-and H_(2)O_(2)-Mediated Ascorbate-Glutathione Cycle in the Drought Stress Responses of Wheat Roots

Abscisic acid(ABA),hydrogen peroxide(H_(2)O_(2)) and ascorbate(AsA)–glutathione(GSH)cycle are widely known for their participation in various stresses.However,the relationship between ABA and H_(2)O_(2) levels and the AsA–GSH cycle under drought stress in wheat has not been studied.In this study,a hydroponic experiment was conducted in wheat seedlings subjected to 15%polyethylene glycol(PEG)6000–induced dehydration.Drought stress caused the rapid accumulation of endogenous ABA and H_(2)O_(2) and significantly decreased the number of root tips compared with the control.The application of ABA significantly increased the number of root tips,whereas the application of H_(2)O_(2) markedly reduced the number of root tips,compared with that under 15%PEG-6000.In addition,drought stress markedly increased the DHA,GSH and GSSG levels,but decreased the AsA levels,AsA/DHA and GSH/GSSG ratios compared with those in the control.The activities of the four enzymes in the AsA–GSH cycle were also markedly increased under drought stress,including glutathione reductase(GR),ascorbate peroxidase(APX),monodehydroascorbate reductase(MDHAR)and dehydroascorbate reductase(DHAR),compared with those in the control.However,the application of an ABA inhibitor significantly inhibited GR,DHAR and APX activities,whereas the application of an H_(2)O_(2) inhibitor significantly inhibited DHAR and MDHAR activities.Furthermore,the application of ABA inhibitor significantly promoted the increases of H_(2)O_(2) and the application of H_(2)O_(2) inhibitor significantly blocked the increases of ABA,compared with those under 15% PEG-6000.Taken together,the results indicated that ABA and H_(2)O_(2) probably interact under drought stress in wheat;and both of them can mediate drought stress by modulating the enzymes in AsA–GSH cycle,where ABA acts as the main regulator of GR,DHAR,and APX activities,and H_(2)O_(2) acts as the main regulator of DHAR and MDHAR activities.

Genome-wide association study of grain micronutrient concentrations in bread wheat

Bread wheat(Triticum aestivum)is a staple food crop worldwide.The genetic dissection of important nutrient traits is essential for the biofortification of wheat to meet the nutritional needs of the world's growing population.Here,45,298 single-nucleotide polymorphisms(SNPs)from 55K chip arrays were used to genotype a panel of 768 wheat cultivars,and a total of 154 quantitative trait loci(QTLs)were detected for eight traits under three environments by genome-wide association study(GWAS).Three QTLs(qMn-3B.1,qFe-3B.4,and qSe-3B.1/qFe-3B.6)detected repeatedly under different environments or traits were subjected to subsequent analyses based on linkage disequilibrium decay and the P-values of significant SNPs.Significant SNPs in the three QTL regions formed six haplotypes for qMn-3B.1,three haplotypes for qFe-3B.4,and three haplotypes for qSe-3B.1/qFe-3B.6.Phenotypic analysis revealed significant differences among haplotypes.These results indicated that the concentrations of several nutrient elements have been modified during the domestication of landraces to modern wheat.Based on the QTL regions,we identified 15 high-confidence genes,eight of which were stably expressed in different tissues and/or developmental stages.TraesCS3B02G046100 in qMn-3B.1 and TraesCS3B02G199500 in qSe-3B.1/qFe-3B.6 were both inferred to interact with metal ions according to the Gene Ontology(GO)analysis.TraesCS3B02G199000,which belongs to qSe-3B.1/qFe-3B.6,was determined to be a member of the WRKY gene family.Overall,this study provides several reliable QTLs that may significantly affect the concentrations of nutrient elements in wheat grain,and this information will facilitate the breeding of wheat cultivars with improved grain properties.

The nitrogen transformation behavior based on the pyrolysis products of wheat straw

In order to provide basic design parameters for the industrial pyrolysis process,the transformation behavior of nitrogen was investigated using wheat straw as raw material.The distributions of nitrogen in pyrolysis char,oil,and gas were obtained and the nitrogenous components in the products were analyzed systematically by X-ray photoelectron spectroscopy(XPS),pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS)and thermogravimetric-Fourier transform infrared spectrometry(TG-FTIR).The nitrogen distribution ranges of the pyrolysis char,oil,and gas were 37.34%–54.82%,32.87%–40.94%and 10.20%–28.83%,respectively.More nitrogen was retained in char at lower pyrolysis temperature and the nitrogen distribution of oil was from rise to decline with increasing temperature.The most abundant N-containing compounds in three-phase products were pyrrole-N,amines,and HCN,respectively.In addition,the transformation mechanism of nitrogen from wheat straw to pyrolysis products was concluded.

Heterogeneous population distribution enhances resistance to wheat lodging by optimizing the light environment

Lodging is still the key factor that limits continuous increases in wheat yields today,because the mechanical strength of culms is reduced due to low-light stress in populations under high-yield cultivation.The mechanical properties of the culm are mainly determined by lignin,which is affected by the light environment.However,little is known about whether the light environment can be sufficiently improved by changing the population distribution to inhibit culm lodging.Therefore,in this study,we used the wheat cultivar“Xinong 979”to establish a low-density homogeneous distribution treatment(LD),high-density homogeneous distribution treatment(HD),and high-density heterogeneous distribution treatment(HD-h)to study the regulatory effects and mechanism responsible for differences in the lodging resistance of wheat culms under different population distributions.Compared with LD,HD significantly reduced the light transmittance in the middle and basal layers of the canopy,the net photosynthetic rate in the middle and lower leaves of plants,the accumulation of lignin in the culm,and the breaking resistance of the culm,and thus the lodging index values increased significantly,with lodging rates of 67.5%in 2020–2021 and 59.3%in 2021–2022.Under HD-h,the light transmittance and other indicators in the middle and basal canopy layers were significantly higher than those under HD,and the lodging index decreased to the point that no lodging occurred.Compared with LD,the activities of phenylalanine ammonia-Lyase(PAL),4-coumarate:coenzyme A ligase(4CL),catechol-O-methyltransferase(COMT),and cinnamyl-alcohol dehydrogenase(CAD)in the lignin synthesis pathway were significantly reduced in the culms under HD during the critical period for culm formation,and the relative expression levels of TaPAL,Ta4CL,TaCOMT,and TaCAD were significantly downregulated.However,the activities of lignin synthesis-related enzymes and their gene expression levels were significantly increased under HD-h compared with HD.A partial least squares path modeling analysis found significant positive effects between the canopy light environment,the photosynthetic capacity of the middle and lower leaves of plants,lignin synthesis and accumulation,and lodging resistance in the culms.Thus,under conventional high-density planting,the risk of wheat lodging was significantly higher.Accordingly,the canopy light environment can be optimized by changing the heterogeneity of the population distribution to improve the photosynthetic capacity of the middle and lower leaves of plants,promote lignin accumulation in the culm,and enhance lodging resistance in wheat.These findings provide a basis for understanding the mechanism responsible for the lower mechanical strength of the culm under high-yield wheat cultivation,and a theoretical basis and for developing technical measures to enhance lodging resistance.

Erratum

For the paper,Fine mapping and characterization of a major QTL for grain length,QGl.cau-2D.1,that has pleiotropic effects in synthetic allohexaploid wheat,published in Journal of Integrative Agriculture 2024,Vol.23,No.9,on page 2911-2922,the authors regret to apprise about a post-publication mistake in Fig.2 of the article.There are errors in the number of populations.The new corrected Fig.2 is provided in this corrigendum to match with the corresponding text.