Flower organ identity in rice is mainly determined by the A-,B-,C-and E-class genes,with the majority encoding MADS-box transcription factors.However,few studies have investigated how the expression of these floral or...Flower organ identity in rice is mainly determined by the A-,B-,C-and E-class genes,with the majority encoding MADS-box transcription factors.However,few studies have investigated how the expression of these floral organ identity genes is regulated during flower development.In this study,we identified a gene named SUPER WOMAN 2(SPW2),which is necessary for spikelet/floret development in rice by participating in the regulation of the expression of pistil identity genes such as OsMADS3,OsMADS13,OsMADS58 and DL.In the spw2 mutant,ectopic stigma/ovary-like tissues were observed in the non-pistil organs,including sterile lemma,lemma,palea,lodicule,and stamen,suggesting that the identities of these organs were severely affected by mutations in SPW2.SPW2 was shown to encode a plant-specific EMF1-like protein that is involved in H3K27me3 modification as an important component of the PRC2 complex.Expression analysis showed that the SPW2 mutation led to the ectopic expression of OsMADS3,OsMADS13,OsMADS58,and DL in non-pistil organs of the spikelet.The ChIP-qPCR results showed significant reductions in the levels of H3K27me3 modification on the chromatin of these genes.Thus,we demonstrated that SPW2 can mediate the process of H3K27me3 modification of pistil-related genes to regulate their expression in non-pistil organs of spikelets in rice.The results of this study expand our understanding of the molecular mechanism by which SPW2 regulates floral organ identity genes through epigenetic regulation.展开更多
The changes in activities of key enzymes involved in sucrose-to-starch conversion and concentrations of hormones in superior and inferior spikelets of super rice were investigated and their association with grain fill...The changes in activities of key enzymes involved in sucrose-to-starch conversion and concentrations of hormones in superior and inferior spikelets of super rice were investigated and their association with grain filling was analyzed.Four super rice cultivars,Liangyoupeijiu,IIyou 084,Huaidao 9 and Wujing 15,and two high-yielding and elite check cultivars,Shanyou 63 and Yangfujing 8,were used.The activities of sucrose synthase （SuSase）,adenosine diphosphoglucose pyrophosphorylase （AGPase）,starch synthase （StSase） and starch branching enzyme （SBE）,and the concentrations of zeatin ＋ zeatin riboside （Z ＋ ZR）,indole-3-acetic acid （IAA） and abscisic acid （ABA） in superior and inferior spikelets were determined during the grain filling period and their relationships with grain filling rate were analyzed.Maximum grain filling rate,the time reaching the maximum grain-filling rate,mean grain filling rate and brown rice weight for superior spikelets showed a slight difference between the super and check rice cultivars,but were significantly lower in the super rice than in the check rice for inferior spikelets.Changes of enzyme activities and hormone concentrations in grains exhibited single peak curves during the grain filling period.The peak values and the mean activities of SuSase,AGPase,StSase and SBE were lower in inferior spikelets than in superior ones,as well as the peak values and the mean concentrations of Z ＋ ZR and IAA.However,the peak value and the mean concentration of ABA were significantly higher in inferior spikelets than in superior ones and greater in the super rice than in the check rice.The grain filling rate was positively and significantly correlated with the activities of SuSase,AGPase and StSase and the concentrations of Z ＋ ZR and IAA.The results suggested that the low activities of SuSase,AGPase and StSase and the low concentrations of Z ＋ ZR and IAA might be important physiological reasons for the slow grain filling rate and light grain weight of inferior spikelets in super rice.展开更多
Temperature of a plant organ constitutes an integrative index to its eco-physiological properties and status.However,little attempt has been made to dissect the combined effect of ecological and physiological factors ...Temperature of a plant organ constitutes an integrative index to its eco-physiological properties and status.However,little attempt has been made to dissect the combined effect of ecological and physiological factors on the surface temperature of a plant organ such as the rice spikelet.In this study,using a deactivated plant as reference,we developed a novel comparison method to dissect the environmental and physiological effects on temperature of rice spikelet.Three japonica rice cultivars with contrasting canopy features were used as testing materials.Temperatures of flag leaf,superior and inferior spikelets and their diurnal rhythm during grain filling stage were precisely measured by a hand-held infrared thermometer.The results showed that the variation of environmental conditions within a panicle was relatively minor,posing a limited influence on temperature difference between the superior and inferior spikelet.On the other hand,it was the intrinsic physiological properties that considerably affected the spatial variations of spikelet temperature within a panicle.Chemical analysis of sucrose and starch in grains and bracts indicated that the superior spikelet is more physiologically active at photosynthetic assimilation and starch biosynthesis.Interestingly,sugar in bracts exhibited a pattern of diurnal changes similar to the source leaf but different from the sink grain,confirming that bracts are source organs for grain filling.Our findings yield penetrating insight into the eco-physiological foundation of spikelet temperature,thus being helpful for the application of physiological approaches in crop breeding for cooler canopy.展开更多
The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quali...The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality.Two rice cultivars,Yangdao 6 （indica） and Yangjing 9538 （japonica）,were field-grown,and the grain filling characters and contents of starch,soluble sugar,and protein of the spikelets at different positions were studied.There were significant differences in matter accumulation among spikelets at different positions during grain filling.The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation.At the initial and mid filling stages,the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence,but soluble sugar content （SSC） exhibited the opposite trend.The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6,but amylose content in mature spikelets showed no obvious relationship to their flowering sequence.The crude protein content （CPC） of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage,and CPC in the spikelets on the secondary branch was higher than that on the primary branch,but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period.Grain water content （GWC） of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages,especially for the top grain on each primary branch.The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation.展开更多
The grain filling of inferior spikelets is much less complete than that of superior spikelets in rice cultivars with large panicles and numerous spikelets and is promoted by moderate soil drying(MD)post-anthesis.A gro...The grain filling of inferior spikelets is much less complete than that of superior spikelets in rice cultivars with large panicles and numerous spikelets and is promoted by moderate soil drying(MD)post-anthesis.A growing body of evidence has shown that microRNAs function in regulating grain development.However,little is known about the mechanism of microRNA control of grain filling of inferior spikelets in response to MD.In this study,grain filling of inferior spikelets was promoted by MD treatment in Nipponbare.Small-RNA profiling at the most active grain-filling stage was conducted in inferior spikelets under control(CK)and MD treatment.Of 521 known and 128 novel miRNAs,38 known and 9 novel miRNAs were differentially expressed between the CK and MD treatments.Target genes of differentially expressed miRNAs were involved in multiple developmental and signaling pathways associated with catalytic activity,carbohydrate metabolism,and other functions.Both miR1861 and miR397 were upregulated by MD,leading to a decrease in OsSBDCP1 and OsLAC,two negative regulators of SSIIIa activity and BR signaling,respectively.In contrast,miR1432 abundance was reduced by MD,resulting in upregulation of OsACOT and thus an elevated content of both ABA and IAA.These results suggest that both starch synthesis and phytohormone biosynthesis are regulated by differentially expressed miRNAs in inferior spikelets in response to MD treatment.Our results suggest the molecular mechanisms by which miRNAs regulate grain filling in inferior spikelets of rice under moderate soil drying,providing potential application in agriculture to increase rice yields by genetic approaches.展开更多
In rice (Oryza sativa L.), yield is related to characteristics of branches and spikelets. To investigate the effects of late sowing date on differentiation and degeneration of spikelets in rice, field experiments were...In rice (Oryza sativa L.), yield is related to characteristics of branches and spikelets. To investigate the effects of late sowing date on differentiation and degeneration of spikelets in rice, field experiments were conducted in Chongzhou and Hanyuan, China. Differentiation and survival of branches and spikelets in Hanyuan were lower than that of Chongzhou, whereas degeneration was greater than that of Chongzhou. In Chongzhou, sowing date affected differentiation and survival of primary, secondary, and total branches, as well as differentiation and degeneration of secondary and total spikelets. In Hanyuan, sowing date affected degeneration of secondary and total branches, and the survival and degeneration of primary spikelets. Late-sown plants experienced higher temperatures in the jointing to heading period, and there were higher sunshine hours. Rainfall and humidity were higher in Chongzhou, but lower in Hanyuan. Late sowing increased differentiation, degeneration, and survival number of branches and spikelets in Chongzhou. However, in Hanyuan, late sowing increased differentiation and degeneration of branches, but decreased survival of branches, which reduced spikelet differentiation and degeneration, resulting in fewer branches. Thus, the key to higher yield in Chongzhou was to increase differentiation of spikelets, whereas in Hanyuan, it was to reduce degeneration of branches and spikelets.展开更多
Rice yield is heavily reliant on the number of spikelets per panicle,a factor determined by the processes of spikelet differentiation and degeneration.In rice cultivars with large panicles,spikelet degeneration negate...Rice yield is heavily reliant on the number of spikelets per panicle,a factor determined by the processes of spikelet differentiation and degeneration.In rice cultivars with large panicles,spikelet degeneration negates the advantages of large panicle and constrains yield potential.Environmental stress-induced metabolic disorders in plants aggravate spikelet degeneration,with the sensitive period for this process commencing approximately 15‒20 d before panicle heading.Notable positional variations occur within the panicle,with significantly higher spikelet degeneration rates at the basal than at the upper positions.An imbalance of carbon and nitrogen metabolism represents the primary physiological basis for aggravated spikelet degeneration under abiotic stress.Impaired carbon and nitrogen metabolism leads to disordered energy metabolism and disrupted respiratory electron transport,which accelerates the apoptosis of young spikelets through excessive reactive oxygen species accumulation.Sucrose serves as the main carbohydrate source for spikelet development,demonstrating an apical dominance pattern that favors spikelet formation.However,under abiotic stress,the inhibition of sucrose decomposition,rather than sucrose transport impairment,predominantly contributes to aggravated spikelet degeneration at the basal panicle positions.Brassinolide and auxin have a significant relationship with spikelet formation,potentially mediating apical dominance.Specifically,brassinolide enhances sucrose accumulation and utilization,thereby alleviating spikelet degeneration.At present,the mechanisms underlying rice spikelet degeneration have not been fully revealed,and the joint effects of hormones,carbohydrates,and carbon and nitrogen metabolism on this process require further investigation.To reduce the spikelet degeneration,the strategic application of water and fertilizer to establish a stable rice population can enhance the rice plants’resilience to abiotic stress.An effective approach to reducing spikelet degeneration is to increase the dry matter occupancy of each spikelet during the panicle initiation period.展开更多
Grain size is one of the determinants of grain yield,and identifying the genetic loci that control grain size will be helpful for increasing grain yield.In our previous study,a quantitative trait locus(QTL)for grain l...Grain size is one of the determinants of grain yield,and identifying the genetic loci that control grain size will be helpful for increasing grain yield.In our previous study,a quantitative trait locus(QTL)for grain length(GL),QGl.cau-2D.1,was identified from an F2 population developed from the cross between the natural(TAA10)and synthetic(XX329)allohexaploid wheat.In the present study,we mainly fine mapped and validated its genetic effects.To this end,multiple near-isogenic lines(NILs)were obtained through marker-assisted selection with TAA10 as the recurrent parent.The secondary populations derived from 25 heterozygous recombinants were used for fine mapping of QGl.cau-2D.1,and the allele from XX329 significantly increased GL,thousand-grain weight(TGW),total spikelet number per spike(TSN)and spike compactness(SC).Using NILs for XX329(2D+)and TAA10(2D−),we determined the genetic and pleiotropic effects of QGl.cau-2D.1.The target sequences were aligned with the wheat reference genome RefSeq v2.1 and spanned an~0.9 Mb genomic region.TraesCS2D03G0114900(ortholog of Os03g0594700)was predicted as the candidate gene based on whole-genome re-sequencing and expression analyses.In summary,the map-based cloning of QGl.cau-2D.1 will be useful for improving grain weight with enhanced GL and TSN.展开更多
Prezygotic isolation is important for successful fertilization in rice, significantly affecting yield. This study focused on F_(5:6) generation plants derived from inter-subspecific crosses(Nipponbare × KDML105) ...Prezygotic isolation is important for successful fertilization in rice, significantly affecting yield. This study focused on F_(5:6) generation plants derived from inter-subspecific crosses(Nipponbare × KDML105) with low(LS) and high seed-setting rates(HS), in which normal pollen fertility was observed. However, LS plants showed a reduced number of pollen grains adhering to the stigma and fewer pollen tubes reaching the ovules at 4-5 h post-pollination, compared with HS plants. Bulked segregant RNA-Seq analysis of pollinated pistils from the HS and LS groups revealed 249 and 473 differentially expressed genes(DEGs), respectively. Kyoto Encyclopedia of Genes and Genomes analysis of the HS and LS-specific DEGs indicated enrichment in metabolic pathways, pentose and glucuronate interconversions, and flavonoid biosynthesis. Several of these DEGs exhibited co-expression with pollen development genes and formed extensive clusters of co-expression networks. Compared with LS pistils, enzyme genes controlling pectin degradation, such as OsPME35 and OsPLL9, showed similar expression patterns, with higher levels in HS pistils pre-pollination. Os02g0467600, similar to cinnamate 4-hydroxylase gene(CYP73), involved in flavonoid biosynthesis, displayed higher expression in HS pistils post-pollination. Our findings suggest that OsPME35, OsPLL9, and Os02g0467600 contribute to prezygotic isolation by potentially modifying the stigma cell wall(OsPME35 and OsPLL9) and controlling later processes such as pollen-stigma adhesion(Os02g0467600) genes. Furthermore, several DEGs specific to HS and LS were co-localized with QTLs and functional genes associated with spikelet fertility. These findings provide valuable insights for further research on rice spikelet fertility, ultimately contributing to the development of high-yielding rice varieties.展开更多
Florets are the basic structural units of spikelets,and their morphogenesis determines the yield and quality of rice grains.However,whether and how pseudouridine-5’-phosphate glycosidase participates in rice spikelet...Florets are the basic structural units of spikelets,and their morphogenesis determines the yield and quality of rice grains.However,whether and how pseudouridine-5’-phosphate glycosidase participates in rice spikelet development remains an open question.In this study,we identified a novel gene,OsPPG,which encodes a peroxisome-localized pseudouridine-5’-phosphate glycosidase and regulates the development of rice spikelets.osppg mutants exhibited abnormal sterile lemma,lemma,palea,lodicule,stamens,and pistils;male sterility;shorter panicles;and reduced plant height.OsPPG was found to regulate several OsMADS genes,thereby affecting the morphogenesis of rice spikelets.Furthermore,metabolomics revealed that the OsPPG gene was involved in the decomposition of pseudouridine via the pyrimidine metabolism pathway and may affect the jasmonic acid signaling pathway.These results suggest that OsPPG is a key regulator of rice spikelet development.展开更多
Total spikelet number per spike(TSS)is a crucial yield component in wheat.Dissecting and characterizing major stable quantitative trait loci(QTL)associated with TSS can significantly enhance the genetic improvement of...Total spikelet number per spike(TSS)is a crucial yield component in wheat.Dissecting and characterizing major stable quantitative trait loci(QTL)associated with TSS can significantly enhance the genetic improvement of yield potential.In a previous study,we identified a stable major QTL for TSS,named QTss.cas-3D.In the present study,we conducted fine mapping of QTss.cas-3D,interval to approximately 6.35 Mb,ranging from 105.03 to 111.38 Mb,based on the IWGSC RefSeq v2.1.Through genome resequencing and gene function annotation,we identified TraesCS3D03G0308000(TaFT-D2)as the candidate gene.Phenotypic evaluation with paired near-isogenic lines revealed that this locus predominantly increases kernel number per spike by enhancing TSS and fertile spikelet number per spike,without significantly affecting thousand-kernel weight or tiller number.The presence of the TaFT-D2 allele in the parent P3228,which is rare in nature populations,highlights its potential value.This study provides a valuable gene resource and functional marker for wheat molecular breeding aimed at improving TSS and establishes a foundation for gene functional analysis of TaFT-D2.展开更多
Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The e...Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.展开更多
Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplantin...Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplanting—a new machine-transplanting method—and SRNF on hybrid rice yields. A 2-year splitplot experiment(2016–2017) was conducted in Meishan, Sichuan province, China, using two machinetransplanting methods(potted-seedling and blanket-seedling) and three N treatments. Total green leaf area, high-effective leaf area and its rate at heading, net photosynthetic rate of flag leaves 7 days after heading, glutamate synthase(GOGAT) and glutamine synthase(GS) activity after heading, dry matter production, and N accumulation at heading and maturity increased under the potted-seedling method or 70% SRNF as a base + 30% urea application at the panicle initiation stage(SBUP). Stem diameter and number of small and of all vascular bundles at the neck–panicle node in potted-seedling plants increased as a result of increasing numbers of effective panicles, secondary branches, and spikelets. In pottedseedling plants, treatment with SBUP increased the number of large and total vascular bundles at the panicle–neck internode and the number of differentiated and surviving secondary branches and spikelets and decreased the number of ineffective tillers and degenerated secondary branches and spikelets. We conclude that the potted-seedling machine transplanting method and SRNF combined with urea topdressing can strengthen the source–sink relationship in rice, resulting in higher yields.展开更多
Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplu...Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.展开更多
Leaf,spike,stem,and root morphologies are key factors that determine crop growth,development,and productivity.Multiple genes that control these morphological traits have been identified in Arabidopsis,rice,maize,and o...Leaf,spike,stem,and root morphologies are key factors that determine crop growth,development,and productivity.Multiple genes that control these morphological traits have been identified in Arabidopsis,rice,maize,and other plant species.However,little is known about the genomic regions and genes associated with morphological traits in wheat.Here,we identified the ethyl methanesulfonate-derived mutant wheat line M133 that displays multiple morphological changes that include upward-curled leaves,paired spikelets,dwarfism,and delayed heading.Using bulked segregant RNA sequencing(BSR-seq)and a high-resolution genetic map,we identified TraesCS1D02G155200(HBD2)as a potential candidate gene.HB-D2 encodes a class III homeodomain-leucine zipper(HD-ZIP III)transcription factor,and the mutation was located in the miRNA165/166 complementary site,resulting in a resistant allele designated rHb-D2.The relative expression of rHb2 in the mutant plants was significantly higher(P<0.01)than in plants homozygous for the WT allele.Independent resistant mutations that disrupt the miRNA165/166 complementary sites in the A-(rHb-A2)and B-genome(rHb-B2)homoeologs showed similar phenotypic alterations,but the relative intensity of the effects was different.Transgenic plants expressing rHb-D2 gene driven by the maize UBIQUITIN(UBI)promoter showed similar phenotypes to the rHb-D2 mutant.These results confirmed that HB-D2 is the causal gene responsible for the mutant phenotypes.Finally,a survey of 1397 wheat accessions showed that the complementary sites for miRNA165/166 in all three HB2 homoeologs are highly conserved.Our results suggest that HB2 plays an important role in regulating growth and development in wheat.展开更多
Wheat is one of the most essential foods in the world. To increase its productivity, nutrient management is one of the most important factors. To assess the possible role of micronutrients in improving wheat yield, an...Wheat is one of the most essential foods in the world. To increase its productivity, nutrient management is one of the most important factors. To assess the possible role of micronutrients in improving wheat yield, an experiment was conducted to evaluate the wheat performance by foliar application of micronutrients. Treatments consist of T1 = No spray, T2 = Spraying plants with tube well water (control), T3 = Spraying plants with 1.6 kg FeSO4/100 L water/acre, T4 = Spraying plants with 3 kg ZnSO4 (21%)/100 L water/acre, T5 = Spraying plants with 1 kg MnSO4/100 L water/acre, T6 = Spraying plants with (FeSO4 + MnSO4), T7 = Spraying plants with (FeSO4 + ZnSO4), T8 = Spraying plants with (ZnSO4 + MnSO4), and T9 = Spraying plants with (FeSO4 + ZnSO4 + MnSO4). Results showed that foliar application of micronutrients substantially improved plant height, spike length cm, spikelets/spike, grains/spike, test weight, Tillers m-2, grain and biological as well as harvest index of wheat. Among treatments, foliar application of FeSO4 + ZnSO4 + MnSO4 remained comparatively better regarding yield related attributes of展开更多
Tillering is a principal trait for the study of branching and production of more number of panicles for increased grain production in many cereal crops. Most of the semi-dwarf high yielding rice cultivars exhibit a re...Tillering is a principal trait for the study of branching and production of more number of panicles for increased grain production in many cereal crops. Most of the semi-dwarf high yielding rice cultivars exhibit a remarkable degree of stability with respect to their tillering ability and maintain almost a constant tiller number which is genetically fixed for a particular cultivar. However, tiller production in wild species of rice is largely determined by environmental parameters, which supersede genetic features for expression of complete tillering ability. Two species of wild rice like Oryza nivara and Oryza rufipogon were tested for influence of manipulated growing conditions on tiller dynamics by comparing their growth in natural habitats and cemented pots filled with manure added soil. The results revealed a significant enhancement in the number of tiller production as well as biomass accumulation of each tiller with more grain yield in the cultivated conditions in both the species in comparison to the wild situations. The dryland inhabitant O. nivara became mono-tillering and deep water species O. rufipogon produced as many as five tillers with relatively lesser grain yield in their natural environments compared to their cultivated counterparts. From these observations, it is concluded that expression of genetic potential for tiller production is amenable to fluctuation of environmental factors in the wild species of rice and their capacity for adaption to inclement growth conditions.展开更多
[Objective] The aim was to breed the indica-compatible japonica lines（ICJLs）.[Method] The indica-compatibility of 5 candidate ICJLs were tested based on the pollen fertility and spikelet fertility of F1 hybrids with...[Objective] The aim was to breed the indica-compatible japonica lines（ICJLs）.[Method] The indica-compatibility of 5 candidate ICJLs were tested based on the pollen fertility and spikelet fertility of F1 hybrids with 6 indica testers,6 japonica testers and 6 middle testers.[Result] Candidate ICJL G2123,G2417,G2410 and G3005 were grouped into the exceptionally（Specific）indica-compatible lines based on their high indica-compatibility and low japonica-compatibility.Candidate ICJL G2615 was grouped into the non-compatible lines on their low indica-compatibility and low japonica-compatibility.[Conclusion] The testers,fertility identification standards,test methods of pollen fertility and spikelet fertility were discussed when the compatibility of CICJLs was tested.The reason of the indica-compatibility in G2417 was analyzed.展开更多
To achieve optimum yield of wheat, supplementation of soil and foliar applied fertilizers with plant growth regulators is vital to assure effective assimilation of nutrients by plants. A trial was conducted at Gwebi A...To achieve optimum yield of wheat, supplementation of soil and foliar applied fertilizers with plant growth regulators is vital to assure effective assimilation of nutrients by plants. A trial was conducted at Gwebi Agricultural College Farm in Mashonaland West Province of Zimbabwe, during the 2012 winter wheat season (May to August), to evaluate the effects of differing times of application of Tianda 2116 plant growth regulator on the growth and yield of wheat (variety SC Sekuru). The trial was laid out in a Randomized Complete Block Design with three replications. The treatments were: Tianda 2116 applied at the following weeks after planting (WAP): 2 WAP, 3 WAP, 4 WAP, 5 WAP, 6 WAP, 14 WAP and no Tianda 2116 applied (control). No significant differences (P > 0.05) were noted among treatments for mean number of tillers per plant and mean number of spikes per plant. Application of Tianda 2116 at 2 and 3 WAP delayed flowering and physiological maturity. Early application of Tianda 2116 increased the number of spikelets per spike, thousand grain weight and grain yield. Conclusively, Tianda 2116 applied 2 or 3 WAP is effective in reducing growth while enhancing yield parameters in wheat production.展开更多
Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice f...Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 oC to 38 oC with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.展开更多
基金supported by the Chongqing Modern Agricultural Industry Technology System,China(CQMAITS202301)the National Natural Science Foundation of China(32100287 and 31971919)+2 种基金the Natural Science Foundation of Chongqing,China(cstc2020jcyj-jq X0020 and cstc2021ycjh-bgzxm0066)the China Postdoctoral Science Foundation Funded Project(2020M683219)the Fundamental Research Funds for the Central Universities,China(SWU-XDJH202315)。
文摘Flower organ identity in rice is mainly determined by the A-,B-,C-and E-class genes,with the majority encoding MADS-box transcription factors.However,few studies have investigated how the expression of these floral organ identity genes is regulated during flower development.In this study,we identified a gene named SUPER WOMAN 2(SPW2),which is necessary for spikelet/floret development in rice by participating in the regulation of the expression of pistil identity genes such as OsMADS3,OsMADS13,OsMADS58 and DL.In the spw2 mutant,ectopic stigma/ovary-like tissues were observed in the non-pistil organs,including sterile lemma,lemma,palea,lodicule,and stamen,suggesting that the identities of these organs were severely affected by mutations in SPW2.SPW2 was shown to encode a plant-specific EMF1-like protein that is involved in H3K27me3 modification as an important component of the PRC2 complex.Expression analysis showed that the SPW2 mutation led to the ectopic expression of OsMADS3,OsMADS13,OsMADS58,and DL in non-pistil organs of the spikelet.The ChIP-qPCR results showed significant reductions in the levels of H3K27me3 modification on the chromatin of these genes.Thus,we demonstrated that SPW2 can mediate the process of H3K27me3 modification of pistil-related genes to regulate their expression in non-pistil organs of spikelets in rice.The results of this study expand our understanding of the molecular mechanism by which SPW2 regulates floral organ identity genes through epigenetic regulation.
基金supported by the grants from the National Natural Science Foundation of China(NSFC-IRRI Joint Research Project 31061140457)General Project (Grant Nos. 31071360 and 31271641)+2 种基金the National Basic Research Program (Grant No.2009CB118603)the National Key Technology Support Program of China (Grant Nos. 2011BAD16B14 and 2012BAD04B08)the Basic Scientific Research Special Operation Cost of the Central Research Institutions in 2011 (Grant No. 201103003)
文摘The changes in activities of key enzymes involved in sucrose-to-starch conversion and concentrations of hormones in superior and inferior spikelets of super rice were investigated and their association with grain filling was analyzed.Four super rice cultivars,Liangyoupeijiu,IIyou 084,Huaidao 9 and Wujing 15,and two high-yielding and elite check cultivars,Shanyou 63 and Yangfujing 8,were used.The activities of sucrose synthase （SuSase）,adenosine diphosphoglucose pyrophosphorylase （AGPase）,starch synthase （StSase） and starch branching enzyme （SBE）,and the concentrations of zeatin ＋ zeatin riboside （Z ＋ ZR）,indole-3-acetic acid （IAA） and abscisic acid （ABA） in superior and inferior spikelets were determined during the grain filling period and their relationships with grain filling rate were analyzed.Maximum grain filling rate,the time reaching the maximum grain-filling rate,mean grain filling rate and brown rice weight for superior spikelets showed a slight difference between the super and check rice cultivars,but were significantly lower in the super rice than in the check rice for inferior spikelets.Changes of enzyme activities and hormone concentrations in grains exhibited single peak curves during the grain filling period.The peak values and the mean activities of SuSase,AGPase,StSase and SBE were lower in inferior spikelets than in superior ones,as well as the peak values and the mean concentrations of Z ＋ ZR and IAA.However,the peak value and the mean concentration of ABA were significantly higher in inferior spikelets than in superior ones and greater in the super rice than in the check rice.The grain filling rate was positively and significantly correlated with the activities of SuSase,AGPase and StSase and the concentrations of Z ＋ ZR and IAA.The results suggested that the low activities of SuSase,AGPase and StSase and the low concentrations of Z ＋ ZR and IAA might be important physiological reasons for the slow grain filling rate and light grain weight of inferior spikelets in super rice.
基金supported by National Key Research and Development Program of China (2017YFD0300103)the National Natural Science Foundation of China (31771719)+2 种基金National High Technology Research and Development Program of China (2014AA10A605)strategic funding the Biological and Biotechnological Sciences Research Council of the United Kingdomthe Designing Future Wheat Strategic Program (BB/P016855/1)。
文摘Temperature of a plant organ constitutes an integrative index to its eco-physiological properties and status.However,little attempt has been made to dissect the combined effect of ecological and physiological factors on the surface temperature of a plant organ such as the rice spikelet.In this study,using a deactivated plant as reference,we developed a novel comparison method to dissect the environmental and physiological effects on temperature of rice spikelet.Three japonica rice cultivars with contrasting canopy features were used as testing materials.Temperatures of flag leaf,superior and inferior spikelets and their diurnal rhythm during grain filling stage were precisely measured by a hand-held infrared thermometer.The results showed that the variation of environmental conditions within a panicle was relatively minor,posing a limited influence on temperature difference between the superior and inferior spikelet.On the other hand,it was the intrinsic physiological properties that considerably affected the spatial variations of spikelet temperature within a panicle.Chemical analysis of sucrose and starch in grains and bracts indicated that the superior spikelet is more physiologically active at photosynthetic assimilation and starch biosynthesis.Interestingly,sugar in bracts exhibited a pattern of diurnal changes similar to the source leaf but different from the sink grain,confirming that bracts are source organs for grain filling.Our findings yield penetrating insight into the eco-physiological foundation of spikelet temperature,thus being helpful for the application of physiological approaches in crop breeding for cooler canopy.
基金supported by the National Natural Science Foundation of China(Grant Nos.30400276 and 30871480)the National Natural Science Foundation of Major International Cooperation Project(Grant No.31061140457)+1 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK2009005)the Scientific Research Foundation for the Talents of Jiangsu Province,China
文摘The accumulation dynamics of kernel components for spikelets at different positions within a rice panicle were investigated during grain filling to understand the physiological reasons for the variation of grain quality.Two rice cultivars,Yangdao 6 （indica） and Yangjing 9538 （japonica）,were field-grown,and the grain filling characters and contents of starch,soluble sugar,and protein of the spikelets at different positions were studied.There were significant differences in matter accumulation among spikelets at different positions during grain filling.The early-flowering spikelets presented dominance over the late-flowering spikelets in initial time and initial rate of accumulation.At the initial and mid filling stages,the contents and the rates of starch and amylose accumulation in spikelets decreased with the flowering sequence,but soluble sugar content （SSC） exhibited the opposite trend.The difference in SSC among the spikelets of Yangjing 9538 was greater than that of Yangdao 6,but amylose content in mature spikelets showed no obvious relationship to their flowering sequence.The crude protein content （CPC） of early-flowering spikelets decreased more rapidly than that of late-flowering ones at the initial filling stage,and CPC in the spikelets on the secondary branch was higher than that on the primary branch,but CPC in early-flowering ones was lower than that in late-flowering across the whole grain filling period.Grain water content （GWC） of early-flowering spikelets decreased more rapidly than that of late-flowering spikelets on the same branch at the initial and mid filling stages,especially for the top grain on each primary branch.The results suggested that poor grain filling of late-flowering spikelets may be attributed to their low biological activity rather than carbohydrate supply limitation.
基金supported by the National Natural Science Foundation of China(32171927,31971924,U21A201755)the Natural Science Foundation of Hunan Province(2021JJ30349)+3 种基金the Key Research and Development Program of Hunan Province(2018NK1010)Science and Technology Plan of Changsha City(kq2004034)Scientific Research Project of Education Department of Hunan Province(19A245)the Hong Kong Research Grant Council(AoE/M-05/12,AoE/M-403/16,GRF12103219,12103220,14177617).
文摘The grain filling of inferior spikelets is much less complete than that of superior spikelets in rice cultivars with large panicles and numerous spikelets and is promoted by moderate soil drying(MD)post-anthesis.A growing body of evidence has shown that microRNAs function in regulating grain development.However,little is known about the mechanism of microRNA control of grain filling of inferior spikelets in response to MD.In this study,grain filling of inferior spikelets was promoted by MD treatment in Nipponbare.Small-RNA profiling at the most active grain-filling stage was conducted in inferior spikelets under control(CK)and MD treatment.Of 521 known and 128 novel miRNAs,38 known and 9 novel miRNAs were differentially expressed between the CK and MD treatments.Target genes of differentially expressed miRNAs were involved in multiple developmental and signaling pathways associated with catalytic activity,carbohydrate metabolism,and other functions.Both miR1861 and miR397 were upregulated by MD,leading to a decrease in OsSBDCP1 and OsLAC,two negative regulators of SSIIIa activity and BR signaling,respectively.In contrast,miR1432 abundance was reduced by MD,resulting in upregulation of OsACOT and thus an elevated content of both ABA and IAA.These results suggest that both starch synthesis and phytohormone biosynthesis are regulated by differentially expressed miRNAs in inferior spikelets in response to MD treatment.Our results suggest the molecular mechanisms by which miRNAs regulate grain filling in inferior spikelets of rice under moderate soil drying,providing potential application in agriculture to increase rice yields by genetic approaches.
文摘In rice (Oryza sativa L.), yield is related to characteristics of branches and spikelets. To investigate the effects of late sowing date on differentiation and degeneration of spikelets in rice, field experiments were conducted in Chongzhou and Hanyuan, China. Differentiation and survival of branches and spikelets in Hanyuan were lower than that of Chongzhou, whereas degeneration was greater than that of Chongzhou. In Chongzhou, sowing date affected differentiation and survival of primary, secondary, and total branches, as well as differentiation and degeneration of secondary and total spikelets. In Hanyuan, sowing date affected degeneration of secondary and total branches, and the survival and degeneration of primary spikelets. Late-sown plants experienced higher temperatures in the jointing to heading period, and there were higher sunshine hours. Rainfall and humidity were higher in Chongzhou, but lower in Hanyuan. Late sowing increased differentiation, degeneration, and survival number of branches and spikelets in Chongzhou. However, in Hanyuan, late sowing increased differentiation and degeneration of branches, but decreased survival of branches, which reduced spikelet differentiation and degeneration, resulting in fewer branches. Thus, the key to higher yield in Chongzhou was to increase differentiation of spikelets, whereas in Hanyuan, it was to reduce degeneration of branches and spikelets.
基金funded by the National Natural Science Foundation of China(Grant No.32201896)the Zhejiang Province Key Research and Development Plan Project,China(Grant No.2022C02034)the National Modern Agricultural Industrial Technology System Construction Project,China(Grant No.CARS-01-21).
文摘Rice yield is heavily reliant on the number of spikelets per panicle,a factor determined by the processes of spikelet differentiation and degeneration.In rice cultivars with large panicles,spikelet degeneration negates the advantages of large panicle and constrains yield potential.Environmental stress-induced metabolic disorders in plants aggravate spikelet degeneration,with the sensitive period for this process commencing approximately 15‒20 d before panicle heading.Notable positional variations occur within the panicle,with significantly higher spikelet degeneration rates at the basal than at the upper positions.An imbalance of carbon and nitrogen metabolism represents the primary physiological basis for aggravated spikelet degeneration under abiotic stress.Impaired carbon and nitrogen metabolism leads to disordered energy metabolism and disrupted respiratory electron transport,which accelerates the apoptosis of young spikelets through excessive reactive oxygen species accumulation.Sucrose serves as the main carbohydrate source for spikelet development,demonstrating an apical dominance pattern that favors spikelet formation.However,under abiotic stress,the inhibition of sucrose decomposition,rather than sucrose transport impairment,predominantly contributes to aggravated spikelet degeneration at the basal panicle positions.Brassinolide and auxin have a significant relationship with spikelet formation,potentially mediating apical dominance.Specifically,brassinolide enhances sucrose accumulation and utilization,thereby alleviating spikelet degeneration.At present,the mechanisms underlying rice spikelet degeneration have not been fully revealed,and the joint effects of hormones,carbohydrates,and carbon and nitrogen metabolism on this process require further investigation.To reduce the spikelet degeneration,the strategic application of water and fertilizer to establish a stable rice population can enhance the rice plants’resilience to abiotic stress.An effective approach to reducing spikelet degeneration is to increase the dry matter occupancy of each spikelet during the panicle initiation period.
基金supported by the National Key Research and Development Program of China(32172069).
文摘Grain size is one of the determinants of grain yield,and identifying the genetic loci that control grain size will be helpful for increasing grain yield.In our previous study,a quantitative trait locus(QTL)for grain length(GL),QGl.cau-2D.1,was identified from an F2 population developed from the cross between the natural(TAA10)and synthetic(XX329)allohexaploid wheat.In the present study,we mainly fine mapped and validated its genetic effects.To this end,multiple near-isogenic lines(NILs)were obtained through marker-assisted selection with TAA10 as the recurrent parent.The secondary populations derived from 25 heterozygous recombinants were used for fine mapping of QGl.cau-2D.1,and the allele from XX329 significantly increased GL,thousand-grain weight(TGW),total spikelet number per spike(TSN)and spike compactness(SC).Using NILs for XX329(2D+)and TAA10(2D−),we determined the genetic and pleiotropic effects of QGl.cau-2D.1.The target sequences were aligned with the wheat reference genome RefSeq v2.1 and spanned an~0.9 Mb genomic region.TraesCS2D03G0114900(ortholog of Os03g0594700)was predicted as the candidate gene based on whole-genome re-sequencing and expression analyses.In summary,the map-based cloning of QGl.cau-2D.1 will be useful for improving grain weight with enhanced GL and TSN.
基金supported by the Agricultural Research Development Agency of Thailand (Grant No.PRP6405030280)Research Promotion fund for International and Educational Excellence, Thailand (Grant No.08/2562)。
文摘Prezygotic isolation is important for successful fertilization in rice, significantly affecting yield. This study focused on F_(5:6) generation plants derived from inter-subspecific crosses(Nipponbare × KDML105) with low(LS) and high seed-setting rates(HS), in which normal pollen fertility was observed. However, LS plants showed a reduced number of pollen grains adhering to the stigma and fewer pollen tubes reaching the ovules at 4-5 h post-pollination, compared with HS plants. Bulked segregant RNA-Seq analysis of pollinated pistils from the HS and LS groups revealed 249 and 473 differentially expressed genes(DEGs), respectively. Kyoto Encyclopedia of Genes and Genomes analysis of the HS and LS-specific DEGs indicated enrichment in metabolic pathways, pentose and glucuronate interconversions, and flavonoid biosynthesis. Several of these DEGs exhibited co-expression with pollen development genes and formed extensive clusters of co-expression networks. Compared with LS pistils, enzyme genes controlling pectin degradation, such as OsPME35 and OsPLL9, showed similar expression patterns, with higher levels in HS pistils pre-pollination. Os02g0467600, similar to cinnamate 4-hydroxylase gene(CYP73), involved in flavonoid biosynthesis, displayed higher expression in HS pistils post-pollination. Our findings suggest that OsPME35, OsPLL9, and Os02g0467600 contribute to prezygotic isolation by potentially modifying the stigma cell wall(OsPME35 and OsPLL9) and controlling later processes such as pollen-stigma adhesion(Os02g0467600) genes. Furthermore, several DEGs specific to HS and LS were co-localized with QTLs and functional genes associated with spikelet fertility. These findings provide valuable insights for further research on rice spikelet fertility, ultimately contributing to the development of high-yielding rice varieties.
基金partially supported by the Key Program of the National Natural Science of Fujian Province(2022J02010)Science and Technology Project of State Administration of Science,Technology and Industry for National Defense,Seed Innovation and Industrialization Project of Fujian Province(zycxny2021003)Fujian Province Public Welfare Scientific Research Program(2016R1018-8)。
文摘Florets are the basic structural units of spikelets,and their morphogenesis determines the yield and quality of rice grains.However,whether and how pseudouridine-5’-phosphate glycosidase participates in rice spikelet development remains an open question.In this study,we identified a novel gene,OsPPG,which encodes a peroxisome-localized pseudouridine-5’-phosphate glycosidase and regulates the development of rice spikelets.osppg mutants exhibited abnormal sterile lemma,lemma,palea,lodicule,stamens,and pistils;male sterility;shorter panicles;and reduced plant height.OsPPG was found to regulate several OsMADS genes,thereby affecting the morphogenesis of rice spikelets.Furthermore,metabolomics revealed that the OsPPG gene was involved in the decomposition of pseudouridine via the pyrimidine metabolism pathway and may affect the jasmonic acid signaling pathway.These results suggest that OsPPG is a key regulator of rice spikelet development.
基金supported by the National Natural Science Foundation of China (32101686)the Hebei Province Key Research and Development Program (22326306D).
文摘Total spikelet number per spike(TSS)is a crucial yield component in wheat.Dissecting and characterizing major stable quantitative trait loci(QTL)associated with TSS can significantly enhance the genetic improvement of yield potential.In a previous study,we identified a stable major QTL for TSS,named QTss.cas-3D.In the present study,we conducted fine mapping of QTss.cas-3D,interval to approximately 6.35 Mb,ranging from 105.03 to 111.38 Mb,based on the IWGSC RefSeq v2.1.Through genome resequencing and gene function annotation,we identified TraesCS3D03G0308000(TaFT-D2)as the candidate gene.Phenotypic evaluation with paired near-isogenic lines revealed that this locus predominantly increases kernel number per spike by enhancing TSS and fertile spikelet number per spike,without significantly affecting thousand-kernel weight or tiller number.The presence of the TaFT-D2 allele in the parent P3228,which is rare in nature populations,highlights its potential value.This study provides a valuable gene resource and functional marker for wheat molecular breeding aimed at improving TSS and establishes a foundation for gene functional analysis of TaFT-D2.
基金This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA24010104-2).
文摘Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight(TGW)in wheat(Triticum aestivum L.).However,no mutations have been identified within the gene to test this association.The effects of TaSus1 on grain number per spike(GNS)also are largely unknown.Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike(FSN).In the present study,we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing.The triple mutants displayed lower FSN,GNS,grain number per spikelet(GNST),and TGW than wild-type plants.In 306 hexaploid wheat accessions,two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS.Introgression of the two alleles into a wheat genetic background confirmed their effects.The alleles differed in geographical distribution among the accessions.
基金supported by the National Key Research and Development Program of China(2017YFD0301701 and 2017YFD0301706)National Natural Science Foundation of China(31660369)。
文摘Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplanting—a new machine-transplanting method—and SRNF on hybrid rice yields. A 2-year splitplot experiment(2016–2017) was conducted in Meishan, Sichuan province, China, using two machinetransplanting methods(potted-seedling and blanket-seedling) and three N treatments. Total green leaf area, high-effective leaf area and its rate at heading, net photosynthetic rate of flag leaves 7 days after heading, glutamate synthase(GOGAT) and glutamine synthase(GS) activity after heading, dry matter production, and N accumulation at heading and maturity increased under the potted-seedling method or 70% SRNF as a base + 30% urea application at the panicle initiation stage(SBUP). Stem diameter and number of small and of all vascular bundles at the neck–panicle node in potted-seedling plants increased as a result of increasing numbers of effective panicles, secondary branches, and spikelets. In pottedseedling plants, treatment with SBUP increased the number of large and total vascular bundles at the panicle–neck internode and the number of differentiated and surviving secondary branches and spikelets and decreased the number of ineffective tillers and degenerated secondary branches and spikelets. We conclude that the potted-seedling machine transplanting method and SRNF combined with urea topdressing can strengthen the source–sink relationship in rice, resulting in higher yields.
基金Funding was provided by the National Key Research and Development Program of China(2017YFD0301203,2017YFD0300100,and 2018YFD0300803)Jiangsu Agriculture Science and Technology Innovation Fund(CX(18)1002).
文摘Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.
基金supported by the Provincial Natural Science Foundation of Shandong(ZR2021MC056 and ZR2021ZD30)the Open Project Funding of the State Key Laboratory of Crop Stress Adaptation and Improvementfunded by Competitive Grant 202268013-36439(WheatCAP)from the USDA National Institute of Food and Agriculture。
文摘Leaf,spike,stem,and root morphologies are key factors that determine crop growth,development,and productivity.Multiple genes that control these morphological traits have been identified in Arabidopsis,rice,maize,and other plant species.However,little is known about the genomic regions and genes associated with morphological traits in wheat.Here,we identified the ethyl methanesulfonate-derived mutant wheat line M133 that displays multiple morphological changes that include upward-curled leaves,paired spikelets,dwarfism,and delayed heading.Using bulked segregant RNA sequencing(BSR-seq)and a high-resolution genetic map,we identified TraesCS1D02G155200(HBD2)as a potential candidate gene.HB-D2 encodes a class III homeodomain-leucine zipper(HD-ZIP III)transcription factor,and the mutation was located in the miRNA165/166 complementary site,resulting in a resistant allele designated rHb-D2.The relative expression of rHb2 in the mutant plants was significantly higher(P<0.01)than in plants homozygous for the WT allele.Independent resistant mutations that disrupt the miRNA165/166 complementary sites in the A-(rHb-A2)and B-genome(rHb-B2)homoeologs showed similar phenotypic alterations,but the relative intensity of the effects was different.Transgenic plants expressing rHb-D2 gene driven by the maize UBIQUITIN(UBI)promoter showed similar phenotypes to the rHb-D2 mutant.These results confirmed that HB-D2 is the causal gene responsible for the mutant phenotypes.Finally,a survey of 1397 wheat accessions showed that the complementary sites for miRNA165/166 in all three HB2 homoeologs are highly conserved.Our results suggest that HB2 plays an important role in regulating growth and development in wheat.
文摘Wheat is one of the most essential foods in the world. To increase its productivity, nutrient management is one of the most important factors. To assess the possible role of micronutrients in improving wheat yield, an experiment was conducted to evaluate the wheat performance by foliar application of micronutrients. Treatments consist of T1 = No spray, T2 = Spraying plants with tube well water (control), T3 = Spraying plants with 1.6 kg FeSO4/100 L water/acre, T4 = Spraying plants with 3 kg ZnSO4 (21%)/100 L water/acre, T5 = Spraying plants with 1 kg MnSO4/100 L water/acre, T6 = Spraying plants with (FeSO4 + MnSO4), T7 = Spraying plants with (FeSO4 + ZnSO4), T8 = Spraying plants with (ZnSO4 + MnSO4), and T9 = Spraying plants with (FeSO4 + ZnSO4 + MnSO4). Results showed that foliar application of micronutrients substantially improved plant height, spike length cm, spikelets/spike, grains/spike, test weight, Tillers m-2, grain and biological as well as harvest index of wheat. Among treatments, foliar application of FeSO4 + ZnSO4 + MnSO4 remained comparatively better regarding yield related attributes of
文摘Tillering is a principal trait for the study of branching and production of more number of panicles for increased grain production in many cereal crops. Most of the semi-dwarf high yielding rice cultivars exhibit a remarkable degree of stability with respect to their tillering ability and maintain almost a constant tiller number which is genetically fixed for a particular cultivar. However, tiller production in wild species of rice is largely determined by environmental parameters, which supersede genetic features for expression of complete tillering ability. Two species of wild rice like Oryza nivara and Oryza rufipogon were tested for influence of manipulated growing conditions on tiller dynamics by comparing their growth in natural habitats and cemented pots filled with manure added soil. The results revealed a significant enhancement in the number of tiller production as well as biomass accumulation of each tiller with more grain yield in the cultivated conditions in both the species in comparison to the wild situations. The dryland inhabitant O. nivara became mono-tillering and deep water species O. rufipogon produced as many as five tillers with relatively lesser grain yield in their natural environments compared to their cultivated counterparts. From these observations, it is concluded that expression of genetic potential for tiller production is amenable to fluctuation of environmental factors in the wild species of rice and their capacity for adaption to inclement growth conditions.
基金Supported by National High Technology Development Plan Financial Program(101-Z16-02-01,2001AA211181)~~
文摘[Objective] The aim was to breed the indica-compatible japonica lines（ICJLs）.[Method] The indica-compatibility of 5 candidate ICJLs were tested based on the pollen fertility and spikelet fertility of F1 hybrids with 6 indica testers,6 japonica testers and 6 middle testers.[Result] Candidate ICJL G2123,G2417,G2410 and G3005 were grouped into the exceptionally（Specific）indica-compatible lines based on their high indica-compatibility and low japonica-compatibility.Candidate ICJL G2615 was grouped into the non-compatible lines on their low indica-compatibility and low japonica-compatibility.[Conclusion] The testers,fertility identification standards,test methods of pollen fertility and spikelet fertility were discussed when the compatibility of CICJLs was tested.The reason of the indica-compatibility in G2417 was analyzed.
文摘To achieve optimum yield of wheat, supplementation of soil and foliar applied fertilizers with plant growth regulators is vital to assure effective assimilation of nutrients by plants. A trial was conducted at Gwebi Agricultural College Farm in Mashonaland West Province of Zimbabwe, during the 2012 winter wheat season (May to August), to evaluate the effects of differing times of application of Tianda 2116 plant growth regulator on the growth and yield of wheat (variety SC Sekuru). The trial was laid out in a Randomized Complete Block Design with three replications. The treatments were: Tianda 2116 applied at the following weeks after planting (WAP): 2 WAP, 3 WAP, 4 WAP, 5 WAP, 6 WAP, 14 WAP and no Tianda 2116 applied (control). No significant differences (P > 0.05) were noted among treatments for mean number of tillers per plant and mean number of spikes per plant. Application of Tianda 2116 at 2 and 3 WAP delayed flowering and physiological maturity. Early application of Tianda 2116 increased the number of spikelets per spike, thousand grain weight and grain yield. Conclusively, Tianda 2116 applied 2 or 3 WAP is effective in reducing growth while enhancing yield parameters in wheat production.
基金financially supported by the National Key Research and Development Program of China(Grant No.2017YFD0300409)the National Natural Science Foundation of China(Grant No.31701374)+1 种基金the Special Fund for China Agricultural Research System(Grant Nos.CARS-01-22 and CARS-01-65)the Basic Research Foundation of National Commonweal Research Institute of China(Grant No.2017RG004-4)
文摘Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 oC to 38 oC with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.
