Increasing effective panicle number per plant(EPN)is one approach to increase yield potential in rice.However,molecular mechanisms underlying EPN remain unclear.In this study,we integrated mapbased cloning and genome-...Increasing effective panicle number per plant(EPN)is one approach to increase yield potential in rice.However,molecular mechanisms underlying EPN remain unclear.In this study,we integrated mapbased cloning and genome-wide association analysis to identify the EPN4 gene,which is allelic to NARROW LEAF1(NAL1).Overexpression lines containing the Teqing allele(TQ)of EPN4 had significantly increased EPN.NIL-EPN4^(TQ) in japonica(geng)cultivar Lemont(LT)exhibited significantly improved EPN but decreased grain number and flag leaf size relative to LT.Haplotype analysis indicated that accessions with EPN4-1 had medium EPN,medium grain number,and medium grain weight,but had the highest grain yield among seven haplotypes,indicating that EPN4-1 is an elite haplotype of EPN4 for positive coordination of the three components of grain yield.Furthermore,accessions carrying the combination of EPN4-1 and haplotype GNP1-6 of GNP1 for grain number per panicle showed higher grain yield than those with other allele combinations.Therefore,pyramiding of EPN4-1 and GNP1-6 could be a preferred approach to obtain high yield potential in breeding.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
Delays in sowing have significant effects on the grain yield,yield components,and grain protein concentrations of winter wheat.However,little is known about how delayed sowing affects these characteristics at differen...Delays in sowing have significant effects on the grain yield,yield components,and grain protein concentrations of winter wheat.However,little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes.In this study,the effects of sowing date were investigated in a winter wheat cultivar,Shannong 30,which was sown in 2019 and 2020 on October 8(normal sowing)and October 22(late sowing)under field conditions.Delayed sowing increased the partitioning of ^(13)C-assimilates to spikes,particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet.Consequently,the increase in grain number was the greatest for the apical sections,followed by the basal and central sections.No significant differences were observed between sowing dates in the superior grain number in the basal and central sections,while the number in apical sections was significantly different.The number of inferior grains in each section also increased substantially in response to delayed sowing.The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and ^(13)C-assimilate partitioning to grains at specific positions in the spikes.Increases in grain number m^(–2) resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains.Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections,followed by the central and apical sections.No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing.In conclusion,a 2-week delay in sowing improved grain yield through increased grain number per spike,which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet.However,grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.展开更多
Agropyron cristatum(2n=4x=28,PPPP),which harbours many high-yield and disease-resistance genes,is a promising donor for wheat improvement.Narrow genetic diversity and the trade-off between grain weight and grain numbe...Agropyron cristatum(2n=4x=28,PPPP),which harbours many high-yield and disease-resistance genes,is a promising donor for wheat improvement.Narrow genetic diversity and the trade-off between grain weight and grain number have become bottlenecks for increasing grain yield in wheat.In this study,a novel translocation line,WAT650l,was derived from the chromosome 6P addition line 4844–12,which can simultaneously increase both grain number per spike(GNS)and thousand-grain weight(TGW).Cytological analysis and molecular marker analysis revealed that WAT650l was a 5BL.5BS-6PL(bin 12–17)translocation line.Assessment of agronomic traits and analysis of the BC4F2 and BC5F2 populations suggested that the 6PL terminal chromosome segment in WAT650l resulted in increased grain number per spike(average increased by 14.07 grains),thousand-grain weight(average increased by 4.31 g),flag leaf length,plant height,spikelet number per spike and kernel number per spikelet during the two growing seasons of 2020–2021 and 2021–2022.Additionally,the increased GNS locus and high-TGW locus of WAT650l were mapped to the bins 16–17 and 12–13,respectively,on chromosome 6PL by genetic population analysis of three translocation lines.In summary,we provide a valuable germplasm resource for broadening the genetic base of wheat and overcoming the negative relationship between GNS and TGW in wheat breeding.展开更多
Late spring cold(LSC) occurred in the reproductive period of wheat impairs spike and floret differentiation during the reproductive period,when young spikelets are very cold-sensitive.However,under LSC,the responses o...Late spring cold(LSC) occurred in the reproductive period of wheat impairs spike and floret differentiation during the reproductive period,when young spikelets are very cold-sensitive.However,under LSC,the responses of wheat spikelets at various positions,leaves,and stems and the interactions between them at physiological levels remain unclear.In the present study,two-year treatments at terminal spikelet stage under two temperatures(2 C,-2 C) and durations(1,2,and 3 days) were imposed in an artificial climate chamber to compare the effects of LSC on grain number and yield in the wheat cultivars Yannong 19(YN19,cold-tolerant) and Xinmai 26(XM26,cold-sensitive).The night temperature regimes were designed to reproduce natural temperature variation.LSC delayed plant growth and inhibited spike and floret differentiation,leading to high yield losses in both cultivars.LSC reduced dry matter accumulation(DMA,g) in spikes,stems,and leaves,reducing the DMA ratios of the spike to leaf and spike to stem.Plant cell wall invertase(CWINV) activity increased in upper and basal spikelets in YN19,whereas CWINV increased in middle spikelets in XM26.Under LSC,soluble sugar and glucose were transported and distributed mainly in upper and basal spikelets for glume and rachis development,so that spike development was relatively complete in YN19,whereas the upper and basal spikelets were severely damaged and most of the glumes in middle spikelets were relatively completely developed in XM26,resulting in pollen abortion mainly in upper and basal spikelets.The development of glumes and rachides was influenced and grain number per spike was decreased after LSC,with kernels present mainly in middle spikelets.Overall,reduced total DMA and dry matter partitioning to spikes under LSC results in poor spikelet development,leading to high losses of grain yield.展开更多
The yield of wheat in wheat–rice rotation cropping systems in the Yangtze River Plain, China, is adversely impacted by waterlogging. A raised bed planting(RBP) pattern may reduce waterlogging and increase the wheat y...The yield of wheat in wheat–rice rotation cropping systems in the Yangtze River Plain, China, is adversely impacted by waterlogging. A raised bed planting(RBP) pattern may reduce waterlogging and increase the wheat yield after rice cultivation by improving the grain number per spike. However, the physiological basis for grain formation under RBP conditions remains poorly understood. The present study was performed over two growing seasons(2018/2019and 2019/2020) to examine the effects of the planting pattern(i.e., RBP and flat planting(FP)) on the floret and grain formation features and leaf photosynthetic source characteristics of wheat. The results indicated that implementation of the RBP pattern improved the soil–plant nitrogen(N) supply during floret development, which facilitated balanced floret development, resulting in a 9.5% increase in the number of fertile florets per spike. Moreover, the RBP pattern delayed wheat leaf senescence and increased the photosynthetic source capacity by 13.9%, which produced more assimilates for grain filling. Delayed leaf senescence was attributed to the resultant high leaf N content and enhanced antioxidant metabolism. Correspondingly, under RBP conditions, 7.6–8.6% more grains per spike were recorded, and the grain yield was ultimately enhanced by 10.4–12.7%. These results demonstrate that the improvement of the spike differentiation process and the enhancement of the leaf photosynthetic capacity were the main reasons for the increased grain number per spike of wheat under the RBP pattern, and additional improvements in this technique should be achievable through further investigation.展开更多
Grain number per-panicle is one of the most important components for rice yield. Spikelets on the primary and secondary branches determine the grain number per-panicle in rice. In this study, we identified a natural m...Grain number per-panicle is one of the most important components for rice yield. Spikelets on the primary and secondary branches determine the grain number per-panicle in rice. In this study, we identified a natural mutant, gnp4, lack of lateral spikelet on the secondary branches in the field condition. In addition, the Gnp4 and Lax1-1 double mutant showed dramatically reduced secondary branches and spikelets in panicle at reproductive stage, and tillers at vegetative stage. By map-based cloning approach, and using four F2 segregating populations, the Gnp4 gene was finally mapped to a 10.7-kb region on the long arm of chromosome 4 in rice. In this region, only one gene was predicted, and genomic DNA sequencing of the 10.7-kb region showed no nucleotide differences between the mutant and wild type. Interestingly, we found that the methylation level of several cytosines in the promoter CpG islands region of the predicted gene in gnp4 were different from the wild type. Thus, we propose that the DNA methylation changes at these sites may induce to decrease expression level of Gnp4, consequently, resulting in phenotypic variation.展开更多
Grain number per spike (GNPS) is a major factor in wheat yield breeding. The development of high GNPS germplasm is widely emphasized in wheat-yield breeding. This paper reported two high GNPS wheat germplasm lines, ...Grain number per spike (GNPS) is a major factor in wheat yield breeding. The development of high GNPS germplasm is widely emphasized in wheat-yield breeding. This paper reported two high GNPS wheat germplasm lines, Pubing 3228 and Pubing 3504, which had a stable and wide adaptability to different ecological regions. By exploring a nested cross design with reciprocals using Pubing 3228 or Pubing 3504 as a common parent and investigating the GNPS phenotypes of F1 hybrids in 2007-2008 and F2 populations in 2008-2009 of different cross combinations, the narrow-sense GNPS heritability was up to 49.58 and 52.23%, respectively. Genetic model analysis predictions suggested that GNPS in Pubing 3228 and Pubing 3504 was mainly controlled by additive genetic effects. Correlation analysis results between GNPS and 1 000- kernel weight (TKW) of F2 populations showed that TKW was not influenced with the increase of GNPS. The good coordination among three yield components of spike number per plant (SNPP), GNPS, and TKW in the F2 segregating population implied that selection of good candidate individuals in breeding programs would be relatively straightforward. Overall, our results indicated that Pubing 3228 and Pubing 3504 are two potential germplasm lines for yield improvement of GNPS in pedigree selection of wheat breeding.展开更多
Grain number per spikelet (GNS) is a key determinant of grain yield in wheat.A recombinant inbred line population comprising 300 lines was developed from a cross between a high GNS variety H461 and Chinese Spring from...Grain number per spikelet (GNS) is a key determinant of grain yield in wheat.A recombinant inbred line population comprising 300 lines was developed from a cross between a high GNS variety H461 and Chinese Spring from which the reference genome assembly of bread wheat was obtained.Both parents and the recombinant inbred lines were genotyped using the wheat 55K single nucleotide polymorphism(SNP) array.A high-density genetic map containing 21,197 SNPs was obtained.These markers covered each of the 21 chromosomes with a total linkage distance of 3792.71 c M.Locations of these markers in this linkage map were highly consistent with their physical locations in the genome assembly of Chinese Spring.The two parents and the whole RIL population were assessed for GNS in two consecutive years at two different locations.Based on multi-environment phenotype data and best liner unbiased prediction values,three quantitative trait loci (QTL) for GNS were identified.One of them located on chromosomes 2B and the other two on 2D.Phenotypic variation explained by these loci varied from 3.07%to26.57%.One of these QTL,QGns.sicau-2D-2,was identified in each of all trials conducted.Based on the best linear unbiased prediction values,this locus explained 19.59%–26.57%of phenotypic variation.A KASP(Kompetitive Allele-Specific PCR) marker closely linked with this locus was generated and used to validate the effects of this locus in three different genetic backgrounds.The identified QTL and the KASP marker developed for it will be highly valuable in fine-mapping the locus and in exploiting it for markerassisted selection in wheat breeding programs.展开更多
Grain number per panicle (GNP) is a complex trait controlled by quantitative trait loci (QTL),directly determining grain yield in rice.Identifying GNP-associated QTL is desirable for increasing rice yield.A rice chrom...Grain number per panicle (GNP) is a complex trait controlled by quantitative trait loci (QTL),directly determining grain yield in rice.Identifying GNP-associated QTL is desirable for increasing rice yield.A rice chromosome segment substitution line (CSSL),F771,which showed increased panicle length and GNP,was identified in a set of CSSLs derived from a cross between two indica cultivars,R498 (recipient) and WY11327 (donor).Genetic analysis showed that the panicle traits in F771 were semidominant and controlled by multiple QTL.Six QTL were consistently identified by QTL-seq analysis.Among them,the major QTL q PLN10 for panicle length and GNP was localized to a 121-kb interval between markers N802 and N909 on chromosome 10.Based on quantitative real-time PCR and sequence analysis,TAWAWA1(TAW1),a known regulator of rice inflorescence architecture,was identified as the candidate gene for q PLN10.A near-isogenic line,NIL-TAW1,was developed to evaluate its effects.In comparison with the recurrent parent R498,NIL-TAW1 showed increased panicle length (14.0%),number of secondary branches (20.9%) and GNP (22.0%),and the final grain yield per plant of NIL-TAW1 was increased by18.6%.Transgenic experiments showed that an appropriate expression level of TAW1 was necessary for panicle development.Haplotype analysis suggested that the favorable F771-type (Hap 13) of TAW1was introduced from aus accessions and had great potential value in high-yield breeding both in indica and japonica varieties.Our results provide a promising genetic resource for rice grain yield improvement.展开更多
Complex traits, such as yield components, are inherited in a quantitative manner and typically controlled by quantitative trait loci (QTL). Grain number per panicle (GN) is an important component of yield in rice and
Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism ...Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism underlying these genes remains largely unknown. In this study, we studied the biological function of OsSPL18 during grain and panicle development in rice. Knockout (KO) mutants of OsSPL18exhibited reduced grain width and thickness, panicle length and grain number, but increased tiller number. Cytological analysis showed that OsSPL18 regulates the development of spikelet hulls by affecting cell proliferation. qRT-PCR and GUS staining analyses showed that OsSPL18 was highly expressed in developing young panicles and young spikelet hulls, in agreement with its function in regulating grain and panicle development. Transcriptional activation experiments indicated that OsSPL18is a functional transcription factor with activation domains in both the N-terminus and C-terminus, and both activation domains are indispensable for its biological functions. Quantitative expression analysis showed that DEP1, a major grain number regulator, was significantly down-regulated in OsSPL18 KO lines.Both yeast one-hybrid and dual-luciferase (LUC) assays showed that OsSPL18 could bind to the DEP1promoter, suggesting that OsSPL18 regulates panicle development by positively regulating the expression of DEP1. Sequence analysis showed that OsSPL18 contains the OsmiR156k complementary sequence in the third exon; 5?RLM-RACE experiments indicated that OsSPL18 could be cleaved by OsmiR156k. Taken together, our results uncovered a new OsmiR156k-OsSPL18-DEP1 pathway regulating grain number in rice.展开更多
Hexaploid triticale(×Triticosecale,AABBRR)is an important forage crop and a promising energy plant.Transferring D-genome chromosomes or segments from common wheat(Triticum aestivum)into hexaploid triticale is att...Hexaploid triticale(×Triticosecale,AABBRR)is an important forage crop and a promising energy plant.Transferring D-genome chromosomes or segments from common wheat(Triticum aestivum)into hexaploid triticale is attractive in improving its economically important traits.Here,a hexaploid triticale 6D(6A)substitution line Lin 456 derived from the cross between the octoploid triticale line H400 and the hexaploid wheat Lin 56 was identified and analyzed by genomic in situ hybridization(GISH),fluorescence in situ hybridization(FISH),and molecular markers.The GISH analysis showed that Lin 456 is a hexaploid triticalewith 14 rye(Secale cereale)chromosomes and 28 wheat chromosomes,whereas non-denaturing fluorescence in situ hybridization(ND-FISH)and molecular marker analysis revealed that it is a 6D(6A)substitution line.In contrast to previous studies,the signal of Oligo-pSc119.2 was observed at the distal end of 6DL in Lin 456.The wheat chromosome 6D was associatedwith increased grain weight and decreased spikelet number using the genotypic data combined with the phenotypes of the F2 population in the three environments.The thousand-grain weight and grain width in the substitution individuals were significantly higher than those in the non-substitution individuals in the F2 population across the three environments.We propose that the hexaploid triticale 6D(6A)substitution line Lin 456 can be a valuable and promising donor stock for genetic improvement during triticale breeding.展开更多
Oat (Avena sativa L.) and wheat (Triticum aestivum L.) vary in the structure of their inflores-cences and also in how pollination proceeds within the inflorescence. In both species the grain position in the spikelet d...Oat (Avena sativa L.) and wheat (Triticum aestivum L.) vary in the structure of their inflores-cences and also in how pollination proceeds within the inflorescence. In both species the grain position in the spikelet determines grain weight potential. Primary grains in oat and proximal grains in wheat weigh more than secondary and distal grains. This variation in grain weight can potentially result from differences in post-pollination cell division in the grain. In this study pollination duration and dynamics were analyzed from head samples collected at two-day intervals, starting from the pollination of the most advanced floret. The number of grain cells was determined for individual grains throughout the inflorescence, starting from the pollination event. When mature, grain position in the spikelet and spike was noted and grain weight assessed. Pollination advance in oat proceeded from the uppermost primary floret towards the basal spikelets in ten to eleven days. Within the spikelet, the primary floret was pollinated on average one day earlier than the secondary floret. In wheat, pollination duration was four to five days, starting from the proximal florets in the mid-section of the inflorescence progressing towards the apical and basal spikelets. Proximal florets were pollinated one to two days earlier than distal florets. Maximum cell number in primary grains exceeded that of secondary grains in two oat cultivars. Similarly, primary grains were heavier than secondary grains. Cell number and single grain weight were correlated in terms of grain position in the spikelet (primary – secondary) and cultivar. Oat cultivar Belinda had a higher single grain weight than Fiia, which was also expressed as larger grain cell number. In wheat, proximal grains had higher maximum cell numbers and were also heavier than distal grains. This grain weight gradient was apparent throughout the inflorescence. Consequently, grain cell number is one of the possible regulators of grain-filling capacity in both cereal crops.展开更多
Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilizati...Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilization is largely unknown.A high temporal-resolution investigation of floret primordia number and morphology,dry matter,and N availability was conducted under three N fertilization levels:0(N0),120(N1)and 240(N2)kg ha^(−1).Interestingly,fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage:meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets.Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability,the NFFs increased gradually as N application increased,but the increase range decreased under N2.There were no differences in spike N concentration among treatments,but leaf N concentration was increased in the N1 and N2 treatments.Correspondingly,dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0.Clearly,optimal N fertilization increased leaf N availability and transport of assimilates to spikes,and allowed more floret primordia to acquire meiotic ability and become fertile florets,finally increasing NFFs.There was no difference in leaf N concentration between N1 and N2 treatment,whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment,implying that there was still some N fertilization that remained unused.Therefore,improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.展开更多
基金This work was funded by the National Key Research and Development Program of China(2023YFF1000404)the Shenzhen Basic Research and Development Key Program of China(JCYJ20200109150713553)Hainan Key Research and Development in Modern Agriculture of China(ZDYF2021Y128).
文摘Increasing effective panicle number per plant(EPN)is one approach to increase yield potential in rice.However,molecular mechanisms underlying EPN remain unclear.In this study,we integrated mapbased cloning and genome-wide association analysis to identify the EPN4 gene,which is allelic to NARROW LEAF1(NAL1).Overexpression lines containing the Teqing allele(TQ)of EPN4 had significantly increased EPN.NIL-EPN4^(TQ) in japonica(geng)cultivar Lemont(LT)exhibited significantly improved EPN but decreased grain number and flag leaf size relative to LT.Haplotype analysis indicated that accessions with EPN4-1 had medium EPN,medium grain number,and medium grain weight,but had the highest grain yield among seven haplotypes,indicating that EPN4-1 is an elite haplotype of EPN4 for positive coordination of the three components of grain yield.Furthermore,accessions carrying the combination of EPN4-1 and haplotype GNP1-6 of GNP1 for grain number per panicle showed higher grain yield than those with other allele combinations.Therefore,pyramiding of EPN4-1 and GNP1-6 could be a preferred approach to obtain high yield potential in breeding.
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Financial support was received from the National Key Research and Development Program of China(2016YFD0300403 and 2017YFD0201705)。
文摘Delays in sowing have significant effects on the grain yield,yield components,and grain protein concentrations of winter wheat.However,little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes.In this study,the effects of sowing date were investigated in a winter wheat cultivar,Shannong 30,which was sown in 2019 and 2020 on October 8(normal sowing)and October 22(late sowing)under field conditions.Delayed sowing increased the partitioning of ^(13)C-assimilates to spikes,particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet.Consequently,the increase in grain number was the greatest for the apical sections,followed by the basal and central sections.No significant differences were observed between sowing dates in the superior grain number in the basal and central sections,while the number in apical sections was significantly different.The number of inferior grains in each section also increased substantially in response to delayed sowing.The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and ^(13)C-assimilate partitioning to grains at specific positions in the spikes.Increases in grain number m^(–2) resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains.Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections,followed by the central and apical sections.No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing.In conclusion,a 2-week delay in sowing improved grain yield through increased grain number per spike,which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet.However,grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.
基金financially supported by the National Natural Science Foundation of China(32171961)the Agricultural Science and Technology Innovation Program of CAAS(CAASASTIP-2021-ICS)。
文摘Agropyron cristatum(2n=4x=28,PPPP),which harbours many high-yield and disease-resistance genes,is a promising donor for wheat improvement.Narrow genetic diversity and the trade-off between grain weight and grain number have become bottlenecks for increasing grain yield in wheat.In this study,a novel translocation line,WAT650l,was derived from the chromosome 6P addition line 4844–12,which can simultaneously increase both grain number per spike(GNS)and thousand-grain weight(TGW).Cytological analysis and molecular marker analysis revealed that WAT650l was a 5BL.5BS-6PL(bin 12–17)translocation line.Assessment of agronomic traits and analysis of the BC4F2 and BC5F2 populations suggested that the 6PL terminal chromosome segment in WAT650l resulted in increased grain number per spike(average increased by 14.07 grains),thousand-grain weight(average increased by 4.31 g),flag leaf length,plant height,spikelet number per spike and kernel number per spikelet during the two growing seasons of 2020–2021 and 2021–2022.Additionally,the increased GNS locus and high-TGW locus of WAT650l were mapped to the bins 16–17 and 12–13,respectively,on chromosome 6PL by genetic population analysis of three translocation lines.In summary,we provide a valuable germplasm resource for broadening the genetic base of wheat and overcoming the negative relationship between GNS and TGW in wheat breeding.
基金supported by the National Key Research and Development Program of China (2017YFD0300408)the Major Research Projects of Anhui (202003b06020021)the Graduate Innovation Fund of Anhui Agricultural University (2020 ysj-5)。
文摘Late spring cold(LSC) occurred in the reproductive period of wheat impairs spike and floret differentiation during the reproductive period,when young spikelets are very cold-sensitive.However,under LSC,the responses of wheat spikelets at various positions,leaves,and stems and the interactions between them at physiological levels remain unclear.In the present study,two-year treatments at terminal spikelet stage under two temperatures(2 C,-2 C) and durations(1,2,and 3 days) were imposed in an artificial climate chamber to compare the effects of LSC on grain number and yield in the wheat cultivars Yannong 19(YN19,cold-tolerant) and Xinmai 26(XM26,cold-sensitive).The night temperature regimes were designed to reproduce natural temperature variation.LSC delayed plant growth and inhibited spike and floret differentiation,leading to high yield losses in both cultivars.LSC reduced dry matter accumulation(DMA,g) in spikes,stems,and leaves,reducing the DMA ratios of the spike to leaf and spike to stem.Plant cell wall invertase(CWINV) activity increased in upper and basal spikelets in YN19,whereas CWINV increased in middle spikelets in XM26.Under LSC,soluble sugar and glucose were transported and distributed mainly in upper and basal spikelets for glume and rachis development,so that spike development was relatively complete in YN19,whereas the upper and basal spikelets were severely damaged and most of the glumes in middle spikelets were relatively completely developed in XM26,resulting in pollen abortion mainly in upper and basal spikelets.The development of glumes and rachides was influenced and grain number per spike was decreased after LSC,with kernels present mainly in middle spikelets.Overall,reduced total DMA and dry matter partitioning to spikes under LSC results in poor spikelet development,leading to high losses of grain yield.
基金funded by the National Key Research and Development Program of China (2017YFD0301306 and 2018YFD0300906)。
文摘The yield of wheat in wheat–rice rotation cropping systems in the Yangtze River Plain, China, is adversely impacted by waterlogging. A raised bed planting(RBP) pattern may reduce waterlogging and increase the wheat yield after rice cultivation by improving the grain number per spike. However, the physiological basis for grain formation under RBP conditions remains poorly understood. The present study was performed over two growing seasons(2018/2019and 2019/2020) to examine the effects of the planting pattern(i.e., RBP and flat planting(FP)) on the floret and grain formation features and leaf photosynthetic source characteristics of wheat. The results indicated that implementation of the RBP pattern improved the soil–plant nitrogen(N) supply during floret development, which facilitated balanced floret development, resulting in a 9.5% increase in the number of fertile florets per spike. Moreover, the RBP pattern delayed wheat leaf senescence and increased the photosynthetic source capacity by 13.9%, which produced more assimilates for grain filling. Delayed leaf senescence was attributed to the resultant high leaf N content and enhanced antioxidant metabolism. Correspondingly, under RBP conditions, 7.6–8.6% more grains per spike were recorded, and the grain yield was ultimately enhanced by 10.4–12.7%. These results demonstrate that the improvement of the spike differentiation process and the enhancement of the leaf photosynthetic capacity were the main reasons for the increased grain number per spike of wheat under the RBP pattern, and additional improvements in this technique should be achievable through further investigation.
基金funded by the Project of the 973 Program(2010CB125904)the 948 Program (2011-G2B)+1 种基金the National Natural Science Foundation of China(31171521)the National Key Technology R&D Program of China (2009BADA2B01)
文摘Grain number per-panicle is one of the most important components for rice yield. Spikelets on the primary and secondary branches determine the grain number per-panicle in rice. In this study, we identified a natural mutant, gnp4, lack of lateral spikelet on the secondary branches in the field condition. In addition, the Gnp4 and Lax1-1 double mutant showed dramatically reduced secondary branches and spikelets in panicle at reproductive stage, and tillers at vegetative stage. By map-based cloning approach, and using four F2 segregating populations, the Gnp4 gene was finally mapped to a 10.7-kb region on the long arm of chromosome 4 in rice. In this region, only one gene was predicted, and genomic DNA sequencing of the 10.7-kb region showed no nucleotide differences between the mutant and wild type. Interestingly, we found that the methylation level of several cytosines in the promoter CpG islands region of the predicted gene in gnp4 were different from the wild type. Thus, we propose that the DNA methylation changes at these sites may induce to decrease expression level of Gnp4, consequently, resulting in phenotypic variation.
基金the National Basic Research Program of China (2011CB100104)the National Natural Science Foundation of China (31071416)the National High Technology R&D Program of China (2006AA10Z174)
文摘Grain number per spike (GNPS) is a major factor in wheat yield breeding. The development of high GNPS germplasm is widely emphasized in wheat-yield breeding. This paper reported two high GNPS wheat germplasm lines, Pubing 3228 and Pubing 3504, which had a stable and wide adaptability to different ecological regions. By exploring a nested cross design with reciprocals using Pubing 3228 or Pubing 3504 as a common parent and investigating the GNPS phenotypes of F1 hybrids in 2007-2008 and F2 populations in 2008-2009 of different cross combinations, the narrow-sense GNPS heritability was up to 49.58 and 52.23%, respectively. Genetic model analysis predictions suggested that GNPS in Pubing 3228 and Pubing 3504 was mainly controlled by additive genetic effects. Correlation analysis results between GNPS and 1 000- kernel weight (TKW) of F2 populations showed that TKW was not influenced with the increase of GNPS. The good coordination among three yield components of spike number per plant (SNPP), GNPS, and TKW in the F2 segregating population implied that selection of good candidate individuals in breeding programs would be relatively straightforward. Overall, our results indicated that Pubing 3228 and Pubing 3504 are two potential germplasm lines for yield improvement of GNPS in pedigree selection of wheat breeding.
基金supported by the National Natural Science Foundation of China (31771794)the National Key Research and Development Program of China (2016YFD0101004 and 2017YFD0100900)the International Science & Technology Cooperation Program of the Bureau of Science and Technology of Chengdu China (2015DFA306002015-GH03-00008-HZ)。
文摘Grain number per spikelet (GNS) is a key determinant of grain yield in wheat.A recombinant inbred line population comprising 300 lines was developed from a cross between a high GNS variety H461 and Chinese Spring from which the reference genome assembly of bread wheat was obtained.Both parents and the recombinant inbred lines were genotyped using the wheat 55K single nucleotide polymorphism(SNP) array.A high-density genetic map containing 21,197 SNPs was obtained.These markers covered each of the 21 chromosomes with a total linkage distance of 3792.71 c M.Locations of these markers in this linkage map were highly consistent with their physical locations in the genome assembly of Chinese Spring.The two parents and the whole RIL population were assessed for GNS in two consecutive years at two different locations.Based on multi-environment phenotype data and best liner unbiased prediction values,three quantitative trait loci (QTL) for GNS were identified.One of them located on chromosomes 2B and the other two on 2D.Phenotypic variation explained by these loci varied from 3.07%to26.57%.One of these QTL,QGns.sicau-2D-2,was identified in each of all trials conducted.Based on the best linear unbiased prediction values,this locus explained 19.59%–26.57%of phenotypic variation.A KASP(Kompetitive Allele-Specific PCR) marker closely linked with this locus was generated and used to validate the effects of this locus in three different genetic backgrounds.The identified QTL and the KASP marker developed for it will be highly valuable in fine-mapping the locus and in exploiting it for markerassisted selection in wheat breeding programs.
基金supported by the National Transgenic Science and Technology Program (2016ZX08001004-002)the National Key Research and Development Program of China (2016YFD0100406)。
文摘Grain number per panicle (GNP) is a complex trait controlled by quantitative trait loci (QTL),directly determining grain yield in rice.Identifying GNP-associated QTL is desirable for increasing rice yield.A rice chromosome segment substitution line (CSSL),F771,which showed increased panicle length and GNP,was identified in a set of CSSLs derived from a cross between two indica cultivars,R498 (recipient) and WY11327 (donor).Genetic analysis showed that the panicle traits in F771 were semidominant and controlled by multiple QTL.Six QTL were consistently identified by QTL-seq analysis.Among them,the major QTL q PLN10 for panicle length and GNP was localized to a 121-kb interval between markers N802 and N909 on chromosome 10.Based on quantitative real-time PCR and sequence analysis,TAWAWA1(TAW1),a known regulator of rice inflorescence architecture,was identified as the candidate gene for q PLN10.A near-isogenic line,NIL-TAW1,was developed to evaluate its effects.In comparison with the recurrent parent R498,NIL-TAW1 showed increased panicle length (14.0%),number of secondary branches (20.9%) and GNP (22.0%),and the final grain yield per plant of NIL-TAW1 was increased by18.6%.Transgenic experiments showed that an appropriate expression level of TAW1 was necessary for panicle development.Haplotype analysis suggested that the favorable F771-type (Hap 13) of TAW1was introduced from aus accessions and had great potential value in high-yield breeding both in indica and japonica varieties.Our results provide a promising genetic resource for rice grain yield improvement.
文摘Complex traits, such as yield components, are inherited in a quantitative manner and typically controlled by quantitative trait loci (QTL). Grain number per panicle (GN) is an important component of yield in rice and
基金supported by funds from the Rice Molecular Design Breeding (2016YFD0101801)the National Natural Science Foundation of China (91535102 and 31771760)the Open Research Fund of State Key Laboratory of Hybrid Rice (2016KF09)
文摘Grain weight and grain number are two important traits directly determining grain yield in rice. To date,a lot of genes related to grain weight and grain number have been identified; however, the regulatory mechanism underlying these genes remains largely unknown. In this study, we studied the biological function of OsSPL18 during grain and panicle development in rice. Knockout (KO) mutants of OsSPL18exhibited reduced grain width and thickness, panicle length and grain number, but increased tiller number. Cytological analysis showed that OsSPL18 regulates the development of spikelet hulls by affecting cell proliferation. qRT-PCR and GUS staining analyses showed that OsSPL18 was highly expressed in developing young panicles and young spikelet hulls, in agreement with its function in regulating grain and panicle development. Transcriptional activation experiments indicated that OsSPL18is a functional transcription factor with activation domains in both the N-terminus and C-terminus, and both activation domains are indispensable for its biological functions. Quantitative expression analysis showed that DEP1, a major grain number regulator, was significantly down-regulated in OsSPL18 KO lines.Both yeast one-hybrid and dual-luciferase (LUC) assays showed that OsSPL18 could bind to the DEP1promoter, suggesting that OsSPL18 regulates panicle development by positively regulating the expression of DEP1. Sequence analysis showed that OsSPL18 contains the OsmiR156k complementary sequence in the third exon; 5?RLM-RACE experiments indicated that OsSPL18 could be cleaved by OsmiR156k. Taken together, our results uncovered a new OsmiR156k-OsSPL18-DEP1 pathway regulating grain number in rice.
基金supported by the National Key Research and Development Program of China (2017YFD0101004)the National Natural Science Foundation of China (91435204)the Science and Technology Independent Innovation Ability Upgrading Project of Shanxi Academy of Agricultural Sciences (2017ZZCX-23)
文摘Hexaploid triticale(×Triticosecale,AABBRR)is an important forage crop and a promising energy plant.Transferring D-genome chromosomes or segments from common wheat(Triticum aestivum)into hexaploid triticale is attractive in improving its economically important traits.Here,a hexaploid triticale 6D(6A)substitution line Lin 456 derived from the cross between the octoploid triticale line H400 and the hexaploid wheat Lin 56 was identified and analyzed by genomic in situ hybridization(GISH),fluorescence in situ hybridization(FISH),and molecular markers.The GISH analysis showed that Lin 456 is a hexaploid triticalewith 14 rye(Secale cereale)chromosomes and 28 wheat chromosomes,whereas non-denaturing fluorescence in situ hybridization(ND-FISH)and molecular marker analysis revealed that it is a 6D(6A)substitution line.In contrast to previous studies,the signal of Oligo-pSc119.2 was observed at the distal end of 6DL in Lin 456.The wheat chromosome 6D was associatedwith increased grain weight and decreased spikelet number using the genotypic data combined with the phenotypes of the F2 population in the three environments.The thousand-grain weight and grain width in the substitution individuals were significantly higher than those in the non-substitution individuals in the F2 population across the three environments.We propose that the hexaploid triticale 6D(6A)substitution line Lin 456 can be a valuable and promising donor stock for genetic improvement during triticale breeding.
文摘Oat (Avena sativa L.) and wheat (Triticum aestivum L.) vary in the structure of their inflores-cences and also in how pollination proceeds within the inflorescence. In both species the grain position in the spikelet determines grain weight potential. Primary grains in oat and proximal grains in wheat weigh more than secondary and distal grains. This variation in grain weight can potentially result from differences in post-pollination cell division in the grain. In this study pollination duration and dynamics were analyzed from head samples collected at two-day intervals, starting from the pollination of the most advanced floret. The number of grain cells was determined for individual grains throughout the inflorescence, starting from the pollination event. When mature, grain position in the spikelet and spike was noted and grain weight assessed. Pollination advance in oat proceeded from the uppermost primary floret towards the basal spikelets in ten to eleven days. Within the spikelet, the primary floret was pollinated on average one day earlier than the secondary floret. In wheat, pollination duration was four to five days, starting from the proximal florets in the mid-section of the inflorescence progressing towards the apical and basal spikelets. Proximal florets were pollinated one to two days earlier than distal florets. Maximum cell number in primary grains exceeded that of secondary grains in two oat cultivars. Similarly, primary grains were heavier than secondary grains. Cell number and single grain weight were correlated in terms of grain position in the spikelet (primary – secondary) and cultivar. Oat cultivar Belinda had a higher single grain weight than Fiia, which was also expressed as larger grain cell number. In wheat, proximal grains had higher maximum cell numbers and were also heavier than distal grains. This grain weight gradient was apparent throughout the inflorescence. Consequently, grain cell number is one of the possible regulators of grain-filling capacity in both cereal crops.
基金This study was supported by the National Key Research and Development Program of China(2022YFD1900703,2022YFD2300802)the Earmarked Fund for CARS(CARS-3)+1 种基金the National Natural Science Foundation of China(31871563)China Postdoctoral Science Foundation(2022M723437).
文摘Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilization is largely unknown.A high temporal-resolution investigation of floret primordia number and morphology,dry matter,and N availability was conducted under three N fertilization levels:0(N0),120(N1)and 240(N2)kg ha^(−1).Interestingly,fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage:meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets.Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability,the NFFs increased gradually as N application increased,but the increase range decreased under N2.There were no differences in spike N concentration among treatments,but leaf N concentration was increased in the N1 and N2 treatments.Correspondingly,dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0.Clearly,optimal N fertilization increased leaf N availability and transport of assimilates to spikes,and allowed more floret primordia to acquire meiotic ability and become fertile florets,finally increasing NFFs.There was no difference in leaf N concentration between N1 and N2 treatment,whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment,implying that there was still some N fertilization that remained unused.Therefore,improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.