Panicle traits directly associated with yield are a target of selection in rice breeding.Although abundant QTL for panicle traits have been identified,there is little information about the genetic basis of panicle tra...Panicle traits directly associated with yield are a target of selection in rice breeding.Although abundant QTL for panicle traits have been identified,there is little information about the genetic basis of panicle traits in japonica super rice(JSR)cultivars.In this study,we identified QTL for panicle traits in three environments using a population of recombinant inbred lines(RILs)derived from the JSR cultivar Liaoxing 1.A total of 197 RILs were genotyped with 285 polymorphic SNP markers.Phenotypic data and best linear unbiased prediction(BLUP)value of primary branch number(BNP),secondary branch number(BNS),grain number on primary branch(GNP),grain number on secondary branch(GNS),grain number per panicle(GN),panicle length(PL)and grain density(GD)were used for QTL mapping.A total of 105 QTL for seven panicle traits were detected in single environments using their BLUP values.Individual QTL explained 0.51%–52.22%of the phenotypic variation.Of the 105,49 were also detected by joint multi-environment analyses.Five stable QTL:qGD9,qPL9,qGNP9,qGN6,and qBNS6.2 were identified in multiple environments.qGD9,qGNP9,and qPL9,co-localizing on chromosome 9,likely correspond to the known gene DEP1.Importantly,qGN6 and qBNS6.2 in a co-localization region were identified as novel QTL,and their Liaoxing 1 alleles had a positive effect.Several RILs with the QTL allele combinations qGD9/qPL9/qGNP9 and qGN6/qBNS6.2 showed greater GN.Further investigation of the putative gene underlying qGN6/qBNS6.2 would shed light on the molecular mechanism of JSR.展开更多
The relationship between parental genetic differences and the quality and yield of japonica hybrid rice strongly influences japonica hybrid rice breeding.In this study,137 parental lines of japonica hybrid rice were g...The relationship between parental genetic differences and the quality and yield of japonica hybrid rice strongly influences japonica hybrid rice breeding.In this study,137 parental lines of japonica hybrid rice were genotyped using 8 K rice SNP-Chips to characterize their genetic diversity,population structure,and indica-genotype proportion.The genetic diversity of total parental lines averaged 0.264,with values of0.287 for restorer lines and 0.148 for the sterile lines.The introduction of indica lineage increased the genetic diversity of restorer lines relative to that of sterile lines.By model-based population structure analysis,the 137 lines were divided into 14 groups.According to the grouping results,eight restorer lines and five sterile lines were selected from different groups for cross breeding,yielding 40 japonica hybrid rice combinations(F1).Investigation of the yield and quality of these combinations showed that highyield combinations could be obtained by increasing parental genetic distance to 0.8–0.9,a result accomplished largely by the introduction of indica genomic components of restorer lines.To further improve grain quality,the genetic distance between parents should be reduced to 0.4–0.5,suggesting an indicagenotype proportion of 30%–40%for restorer lines.This study may provide a reference for breeding of japonica hybrid rice.展开更多
The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systema...The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systematic study of the Mpemba effect with water and clearly point out the conditions required for the observation of the Mpemba effect.The results demonstrate that hot water usually has a faster cooling rate than cold water.The initial temperature,temperature difference,shape of the container,and water volume influence the heat exchange and the cooling process.Owing to the influential factors of heat exchange,the Mpemba effect can only be observed under specific conditions.This work helps to clarify doubts and confusion about the Mpemba effect and can offer alternative strategies for energy storage and transfer materials.展开更多
Understanding the decay and maintenance of long-term SARS-CoV-2 neutralizing antibodies in infected or vaccinated people and how vaccines protect against other SARS-CoV-2 variants is critical for assessing public vacc...Understanding the decay and maintenance of long-term SARS-CoV-2 neutralizing antibodies in infected or vaccinated people and how vaccines protect against other SARS-CoV-2 variants is critical for assessing public vaccination plans.Here,we measured different plasm antibody levels 2 and 12 months after disease onset,including anti-RBD,anti-N,total neutralizing antibodies,and two neutralizing-antibody clusters.We found that total neutralizing antibodies declined more slowly than total anti-RBD and anti-N IgG.展开更多
The paper presents numerical findings of reinforced concrete interior beam-column joints under monotonic antisymmetrical load.The finite element models considered compression and tension damage were calibrated by test...The paper presents numerical findings of reinforced concrete interior beam-column joints under monotonic antisymmetrical load.The finite element models considered compression and tension damage were calibrated by test results in terms of the load-displacement,failure modes,and strains of longitudinal steel.The emphasis was put on studying the effects of hoop reinforcement ratio in joint core and the axial compression ratio on the responses of the joints.The results show that,in addition to the truss and strut-and-tie mechanisms,the confinement mechanism also existed in the joint core.A certain amount of stirrup is not only able to enhance the confinement in joint core,undertake a part of shear force and thus to increase the shear capacity,prevent the outward buckling of steel bars in column,improve the stress distribution in joint core,delay cracking and restrain the propagation of cracks,but also to increase the yield load,decrease the yield displacement of beam and improve the joint ductility.However,excessive horizontal stirrups contribute little to the joint performance.In a certain range,larger axial compression ratio is beneficial for the joint mechanical behavior,while it is negative when axial compression ratio is too large.展开更多
基金The study was supported by the National Natural Science Foundation of China(31901526)China Postdoctoral Science Foundation Grant(2019M651139)and Liaoning Key Agricultural Program(2019JH1/10200001-2).
文摘Panicle traits directly associated with yield are a target of selection in rice breeding.Although abundant QTL for panicle traits have been identified,there is little information about the genetic basis of panicle traits in japonica super rice(JSR)cultivars.In this study,we identified QTL for panicle traits in three environments using a population of recombinant inbred lines(RILs)derived from the JSR cultivar Liaoxing 1.A total of 197 RILs were genotyped with 285 polymorphic SNP markers.Phenotypic data and best linear unbiased prediction(BLUP)value of primary branch number(BNP),secondary branch number(BNS),grain number on primary branch(GNP),grain number on secondary branch(GNS),grain number per panicle(GN),panicle length(PL)and grain density(GD)were used for QTL mapping.A total of 105 QTL for seven panicle traits were detected in single environments using their BLUP values.Individual QTL explained 0.51%–52.22%of the phenotypic variation.Of the 105,49 were also detected by joint multi-environment analyses.Five stable QTL:qGD9,qPL9,qGNP9,qGN6,and qBNS6.2 were identified in multiple environments.qGD9,qGNP9,and qPL9,co-localizing on chromosome 9,likely correspond to the known gene DEP1.Importantly,qGN6 and qBNS6.2 in a co-localization region were identified as novel QTL,and their Liaoxing 1 alleles had a positive effect.Several RILs with the QTL allele combinations qGD9/qPL9/qGNP9 and qGN6/qBNS6.2 showed greater GN.Further investigation of the putative gene underlying qGN6/qBNS6.2 would shed light on the molecular mechanism of JSR.
基金Seed Industry Innovation Special Project of Shenyang Science and Technology Bureau(21-110-3-01)China Agriculture Research System(CARS-01-55)+1 种基金Liaoning Key Agricultural Program(2019JH1/10200001-2)Hybrid Rice Breeding Subject(2019DD133719)。
文摘The relationship between parental genetic differences and the quality and yield of japonica hybrid rice strongly influences japonica hybrid rice breeding.In this study,137 parental lines of japonica hybrid rice were genotyped using 8 K rice SNP-Chips to characterize their genetic diversity,population structure,and indica-genotype proportion.The genetic diversity of total parental lines averaged 0.264,with values of0.287 for restorer lines and 0.148 for the sterile lines.The introduction of indica lineage increased the genetic diversity of restorer lines relative to that of sterile lines.By model-based population structure analysis,the 137 lines were divided into 14 groups.According to the grouping results,eight restorer lines and five sterile lines were selected from different groups for cross breeding,yielding 40 japonica hybrid rice combinations(F1).Investigation of the yield and quality of these combinations showed that highyield combinations could be obtained by increasing parental genetic distance to 0.8–0.9,a result accomplished largely by the introduction of indica genomic components of restorer lines.To further improve grain quality,the genetic distance between parents should be reduced to 0.4–0.5,suggesting an indicagenotype proportion of 30%–40%for restorer lines.This study may provide a reference for breeding of japonica hybrid rice.
基金This work was financially supported by“Tianfu Emei”Science and Technology Innovation Leader Program in Sichuan Province,UESTC Talent Start-up Funds(A1098531023601208)National Natural Science Foundation of China(21464015,21472235).
文摘The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systematic study of the Mpemba effect with water and clearly point out the conditions required for the observation of the Mpemba effect.The results demonstrate that hot water usually has a faster cooling rate than cold water.The initial temperature,temperature difference,shape of the container,and water volume influence the heat exchange and the cooling process.Owing to the influential factors of heat exchange,the Mpemba effect can only be observed under specific conditions.This work helps to clarify doubts and confusion about the Mpemba effect and can offer alternative strategies for energy storage and transfer materials.
基金This work was supported by the State Key Basic Research Project,Ministry of Science and Technology of P.R.China(2019YFC0810903,2021YFC0864400)NSFC 81971485,Guangdong Key Basic Research Project(2019B1515120068 and 2020B1111330001)the Zhongnanshan Medical Foundation of Guangdong Province(ZNSA2020013)。
文摘Understanding the decay and maintenance of long-term SARS-CoV-2 neutralizing antibodies in infected or vaccinated people and how vaccines protect against other SARS-CoV-2 variants is critical for assessing public vaccination plans.Here,we measured different plasm antibody levels 2 and 12 months after disease onset,including anti-RBD,anti-N,total neutralizing antibodies,and two neutralizing-antibody clusters.We found that total neutralizing antibodies declined more slowly than total anti-RBD and anti-N IgG.
文摘The paper presents numerical findings of reinforced concrete interior beam-column joints under monotonic antisymmetrical load.The finite element models considered compression and tension damage were calibrated by test results in terms of the load-displacement,failure modes,and strains of longitudinal steel.The emphasis was put on studying the effects of hoop reinforcement ratio in joint core and the axial compression ratio on the responses of the joints.The results show that,in addition to the truss and strut-and-tie mechanisms,the confinement mechanism also existed in the joint core.A certain amount of stirrup is not only able to enhance the confinement in joint core,undertake a part of shear force and thus to increase the shear capacity,prevent the outward buckling of steel bars in column,improve the stress distribution in joint core,delay cracking and restrain the propagation of cracks,but also to increase the yield load,decrease the yield displacement of beam and improve the joint ductility.However,excessive horizontal stirrups contribute little to the joint performance.In a certain range,larger axial compression ratio is beneficial for the joint mechanical behavior,while it is negative when axial compression ratio is too large.