The awn can contribute to photosynthesis and carbohydrates,enhancing grain yield in wheat.We mapped QAwn.sxau-5A,a major QTL for awn development in wheat(Triticum aestivum).This QTL was delimited to a 994-kb interval ...The awn can contribute to photosynthesis and carbohydrates,enhancing grain yield in wheat.We mapped QAwn.sxau-5A,a major QTL for awn development in wheat(Triticum aestivum).This QTL was delimited to a 994-kb interval at the B1 locus on chromosome 5A,which included the candidate gene encoding a zinc finger protein(TraesCS5A01G542800)as an awn length inhibitor(ALI).The Ali-A1 allele for the awnless trait showed abundant sequence differences in the promoter regions compared to the ali-A1 allele for the long-awn trait.The results of the swap experiment on the promoters from the two ALI-A1 alleles showed that the two promoters caused a difference in the protein level,indicating the gene was regulated at the transcript level.However,the ali-A1 allele contained an SNP that caused a premature stop codon in its coding region,resulting in a truncated protein compared to the functional Ali-A1 protein.The Ali-A1 protein contained two ethylene-responsive element binding factor-associated amphiphilic repression(EAR)motifs,one at the N terminus(EAR-N)and the other at the C terminus(EAR-C),and they were involved in interactions with the wheat co-repressor protein TOPLESS(TPL1).The ali-A1 protein retained the EAR-N motif but lost the EAR-C motif,resulting in the attenuated ability to interact with TPL1.The tpl1 mutant produced a longer awn compared to the wild type.Ali-A1 repressed the transcription of two downstream genes,TaLRP-A1 and TaARF-B1,involved in endogenous auxin concentrations and auxin responses in wheat.We concluded that the awn length is regulated not only by the ALI-A1 gene at transcript levels but also by Ali-A1 and TPL1 at the protein level in wheat.展开更多
African cultivated rice(Oryza glaberrima)was domesticated from its wild progenitor,Oryza barthii.The transition from long-awn to short-awn or awnless glumes was an important evolutionary event during domestication.A Q...African cultivated rice(Oryza glaberrima)was domesticated from its wild progenitor,Oryza barthii.The transition from long-awn to short-awn or awnless glumes was an important evolutionary event during domestication.A QTL analysis of 331 recombinant inbred lines(RILs)using 194 InDel markers identified five quantitative trait loci(QTL)associated with awn length.Locus qObAwn5 made the highest contribution in regulating awn length and was fine-mapped to a 260-kb genomic interval.RNA-seq and RT-qPCR analyses,combined with CRISPR/Cas9-mediated knockout that disruption of gene G12 caused a significant reduction in awn length indicating that G12 was ObAwn5.Genomic analysis revealed a large structural variation(SV)between W1411 and IRGC104165 within this region,characterized by an inversion and two large deletions.Population genomic analyses revealed that all the cultivated African accessions exhibit a domestication-like(Dom-like)pattern,whereas non-cultivated accessions consisted of two distinct types:W1050-like and W1411-like.The W1411-like type was exclusively found in the AA genome of African wild rice.This discovery of ObAwn5 newly substantiates the independent origin of African cultivated rice.展开更多
Wheat awns contribute to photosynthesis and grain production.In this study,an F2population and F2:3families from a cross between the awned line 7D12 and the Chinese awnless variety Shiyou 20(SY20)were used to identify...Wheat awns contribute to photosynthesis and grain production.In this study,an F2population and F2:3families from a cross between the awned line 7D12 and the Chinese awnless variety Shiyou 20(SY20)were used to identify loci associated with awn length.Bulked-segregant RNA sequencing and linkage mapping identified a single dominant locus in a 0.3 cM interval on chromosome 5AL.Five genes were in the interval,including the recently cloned awn inhibitor B1.Although a single copy of the B1 gene was detected in 7D12,SY20 carried five copies of the gene.Increased copy number of B1 in SY20enhanced gene expression.Based on sequence variation among the promoter regions of five B1 gene copies in SY20,two dominant markers were developed and found to cosegregate with B1 in a population of 931 wheat accessions.All 77 awnless accessions harbored sequence variations in the B1 promoter regions similar to those of SY20 and thus carried multiple copies of the gene,whereas 15 randomly selected awned wheats carried only one copy.These results suggest that an increase in copy number of the B1 gene is associated with inhibition of awn length.展开更多
With globe warming, road safety will change dramatically, especially within the Qinghai-Tibet Plateau permafrost regions. Because of higher elevation and better almospheric transparency, the Qinghai-Tibet Plateau has ...With globe warming, road safety will change dramatically, especially within the Qinghai-Tibet Plateau permafrost regions. Because of higher elevation and better almospheric transparency, the Qinghai-Tibet Plateau has stronger radiation than other regions, which can change the daily variation of ground surface temperature on the Plateau. The awning measure （shading board） is one of the actively protected permafrost measures, which was adopted along the Qinghai-Tibet railway and highway and the Qing-Kang Highway in China. Field test results show that embankment surface month mean net radiation is 60-130 W/m2, but the value is below 20 W/m2 under the shading board, and the reducing level of naRn-al net radiation is 80%-90%. The shading board reduced the heat flow entering into the embankment by 80%,90% or more, with heat entering into the soil on the common embankment, but emitting from the embankment under the shading board. At the same time, ground surface temperature under the shading board is 6-8 ℃ lower than the exposed embankment. Test results show that the shading board measure can rapidly and effectively reduce net radiation and heat flow into the embankment, decrease embankment surface and interior temperature, effectively delay increase rate of soil temperature under globe warming, ensure stability and safety of the embankment, and guarantee unblocked road projects in cold and permafrost regions.展开更多
Objective:To evaluate the intervention effect of awn needle in the treatment of lumbar disc herniation through meta-analysis.Methods:In CNKI,Wanfang Data,PubMed,VIP and other databases,we searched the clinical observa...Objective:To evaluate the intervention effect of awn needle in the treatment of lumbar disc herniation through meta-analysis.Methods:In CNKI,Wanfang Data,PubMed,VIP and other databases,we searched the clinical observation studies on the treatment of patients with lumbar disc herniation with awn needle.The methodological quality of the included studies was evaluated using Cochrane 5.1.0 bias risk assessment criteria and Jadad scale.Revman 5.3 software was used for meta-analysis.Results:A total of 14 randomized controlled trials involving 1186 patients were included,with 595 in the awn needle treatment group and 591 in the control group.Meta-analysis showed that the awn needle treatment group was better than that of the control group in the total effective rate[RR=1.17;95%CI(1.12,1.22);Z=6.66;P<0.00001];the awn needle treatment group was better than the control group in ameliorating VAS score[WMD=-1.07,95%CI(-1.19,-0.95),Z=17.87,P<0.00001];the awn needle treatment group was better than the control group in ameliorating JOA score[WMD=3.18,95%CI(2.64,3.71),Z=11.57,P<0.00001];the awn needle treatment group was better than the control group in the amelioration of ADL score[SMD=2.44,95%CI(0.54,4.35),Z=2.52,P=0.01];the awn needle treatment group was better than the control group in the improvement of SLRT angle[WMD=12.71,95%CI(3.21,22.21),Z=2.62,P=0.009].Conclusion:Awn needle treatment can improve the total effective rate of patients with lumbar disc herniation,relieve the pain of patients,improve the straight leg elevation angle of patients,alleviate the disease development,relieve the symptoms,and improve the quality of life of patients.It is worthy of clinical application.展开更多
In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion w...In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion were presented.展开更多
A wide range of morphological and physiological traits have changed between cultivated rice Oryza sativa and wild rice Oryza rufipogon under domestication. Here, we report cloning of the An-2 gene, encoding the Lonely...A wide range of morphological and physiological traits have changed between cultivated rice Oryza sativa and wild rice Oryza rufipogon under domestication. Here, we report cloning of the An-2 gene, encoding the Lonely Guy Like protein 6 （OsLOGL6）, which catalyzes the final step of cytokinin synthesis in O. rufipogon. The near-isogenic line harboring a wild allele of An-2 in the genetic background of the awnless indica Guangluai 4 shows that An-2 promotes awn elongation by enhancing cell division, but decreases grain production by reducing grains per panicle and tillers per plant. We reveal that a genetic variation in the An-2 locus has a large impact on reducing awn length and increasing tiller and grain numbers in domesticated rice. Analysis of gene expression patterns suggests that An-1 reg- ulates the formation of awn primordial, and An-2 promotes awn elongation. Nucleotide diversity of the An-2 locus in cultivated rice was found to be significantly reduced compared with that of wild rice, suggesting that the An-2 locus was subjected to artificial selection. We therefore propose that the selection of genetic variation in An-2 was due to reduced awn length and increased grain yield in cultivated rice.展开更多
Loss of the awn in some cereals including sorghum is a key transition during cereal domestication or improvement that has facilitated grain harvest and storage.The genetic basis for the loss of awn in sorghum during d...Loss of the awn in some cereals including sorghum is a key transition during cereal domestication or improvement that has facilitated grain harvest and storage.The genetic basis for the loss of awn in sorghum during domestication or improvement remains unknown.Here,we identified a transcription factor gene awn1 encoding an ALOG domain,which is responsible for awn loss during sorghum domestication or improvement.awn1 arose from a gene duplication from chromosome 10 that translocated to chromosome 3,recruiting a new promoter from the neighbouring intergenic region filled with"noncoding DNA",and recreating the first exon and intron.The awn1 acquires high expr`ession after duplication and represses the elongation of awns in domesticated sorghum.Comparative mapping revealed a high collinearity at awn1 paralog locus on chromosome 10 across cereals and awn growth and development was successfully reactivated on the rice spikelet by inactivating rice awn1 orthologue.Further RNA-seq and DAP-seq revealed that as a transcription repressor,AWN1 directly bound to the motif in the regulatory regions from three MADS genes related to flower development and two genes DL and LKS2 for the development of awn,downregulated the expressions of these genes,and then repressed the elongation of awn.The preexistence of regulatory elements in the neighbouring intergenic region of awn1 before domestication signified that noncoding DNA may serve as a treasure trove for evolution during adaptation to a changing world.Our results supported that gene duplication can promptly drive the evolution of gene regulatory network.展开更多
Awns are important morphological markers for wheat and exert a strong physiological effect on wheat yield.The awn elongation suppressor B1 has recently been cloned through association and linkage analysis in wheat.How...Awns are important morphological markers for wheat and exert a strong physiological effect on wheat yield.The awn elongation suppressor B1 has recently been cloned through association and linkage analysis in wheat.However,the mechanism of awn inhibition centered around B1 remains to be clarified.Here,we identified an allelic variant in the coding region of B1 through analysis of re-sequencing data;this variant causes an amino acid substitution and premature termination,resulting in a long-awn phenotype.Transcriptome analysis indicated that B1 inhibited awn elongation by impeding cytokinin-and auxinpromoted cell division.Moreover,B1 directly repressed the expression of TaRAE2 and TaLks2,whose orthologs have been reported to promote awn development in rice or barley.More importantly,we found that TaTCP4 and TaTCP10 synergistically inhibited the expression of B1,and a G-to-A mutation in the B1 promoter attenuated its inhibition by TaTCP4/10.Taken together,our results reveal novel mechanisms of awn development and provide genetic resources for trait improvement in wheat.展开更多
Awnness is a key trait in rice domestication, yet no studies have been conducted on fine mapping or association mapping of the rice awn gene. In this study, we investigated the awnness and genotype of a core collectio...Awnness is a key trait in rice domestication, yet no studies have been conducted on fine mapping or association mapping of the rice awn gene. In this study, we investigated the awnness and genotype of a core collection of 303 cultivated rice varieties and a BC5F2 segregating population of 200 individuals. Combining association and linkage analyses, we mapped the awnness related genes to chromosome 4. Primary association analysis using 24 SSR markers revealed five loci significantly associated with awnness on chromosome 4. The associated markers cover previously identified regions. Fine association mapping was conducted using another 29 markers within a 4-Mb region, covering the associated marker in34, which is close to the awn gene Awn4.1. Seven associated markers were revealed, distributed over an 870-kb region. Combining the fine association mapping and linkage analysis of awnness in the 200 BC5F2 segregating population, we finally identified a 330-kb region as the candidate region for Awn4.1. The results indicate that combining association mapping and linkage mapping provides an efficient and precise approach to both genome-wide mapping and fine mapping of rice genes.展开更多
基金supported by the Grand Science and Technology Special Project in Shanxi Province(202201140601025-2)the National Natural Science Foundation of China(32201749)supported by the Agriculture and Food Research Initiative Competitive Grant 2022-68013-36439(WheatCAP)from the USDA National Institute of Food and Agriculture.
文摘The awn can contribute to photosynthesis and carbohydrates,enhancing grain yield in wheat.We mapped QAwn.sxau-5A,a major QTL for awn development in wheat(Triticum aestivum).This QTL was delimited to a 994-kb interval at the B1 locus on chromosome 5A,which included the candidate gene encoding a zinc finger protein(TraesCS5A01G542800)as an awn length inhibitor(ALI).The Ali-A1 allele for the awnless trait showed abundant sequence differences in the promoter regions compared to the ali-A1 allele for the long-awn trait.The results of the swap experiment on the promoters from the two ALI-A1 alleles showed that the two promoters caused a difference in the protein level,indicating the gene was regulated at the transcript level.However,the ali-A1 allele contained an SNP that caused a premature stop codon in its coding region,resulting in a truncated protein compared to the functional Ali-A1 protein.The Ali-A1 protein contained two ethylene-responsive element binding factor-associated amphiphilic repression(EAR)motifs,one at the N terminus(EAR-N)and the other at the C terminus(EAR-C),and they were involved in interactions with the wheat co-repressor protein TOPLESS(TPL1).The ali-A1 protein retained the EAR-N motif but lost the EAR-C motif,resulting in the attenuated ability to interact with TPL1.The tpl1 mutant produced a longer awn compared to the wild type.Ali-A1 repressed the transcription of two downstream genes,TaLRP-A1 and TaARF-B1,involved in endogenous auxin concentrations and auxin responses in wheat.We concluded that the awn length is regulated not only by the ALI-A1 gene at transcript levels but also by Ali-A1 and TPL1 at the protein level in wheat.
基金supported by the National Natural Science Foundation of China (31925029,32401815)
文摘African cultivated rice(Oryza glaberrima)was domesticated from its wild progenitor,Oryza barthii.The transition from long-awn to short-awn or awnless glumes was an important evolutionary event during domestication.A QTL analysis of 331 recombinant inbred lines(RILs)using 194 InDel markers identified five quantitative trait loci(QTL)associated with awn length.Locus qObAwn5 made the highest contribution in regulating awn length and was fine-mapped to a 260-kb genomic interval.RNA-seq and RT-qPCR analyses,combined with CRISPR/Cas9-mediated knockout that disruption of gene G12 caused a significant reduction in awn length indicating that G12 was ObAwn5.Genomic analysis revealed a large structural variation(SV)between W1411 and IRGC104165 within this region,characterized by an inversion and two large deletions.Population genomic analyses revealed that all the cultivated African accessions exhibit a domestication-like(Dom-like)pattern,whereas non-cultivated accessions consisted of two distinct types:W1050-like and W1411-like.The W1411-like type was exclusively found in the AA genome of African wild rice.This discovery of ObAwn5 newly substantiates the independent origin of African cultivated rice.
基金supported by the National Key Research and Development Program of China(2018YFD0300501)。
文摘Wheat awns contribute to photosynthesis and grain production.In this study,an F2population and F2:3families from a cross between the awned line 7D12 and the Chinese awnless variety Shiyou 20(SY20)were used to identify loci associated with awn length.Bulked-segregant RNA sequencing and linkage mapping identified a single dominant locus in a 0.3 cM interval on chromosome 5AL.Five genes were in the interval,including the recently cloned awn inhibitor B1.Although a single copy of the B1 gene was detected in 7D12,SY20 carried five copies of the gene.Increased copy number of B1 in SY20enhanced gene expression.Based on sequence variation among the promoter regions of five B1 gene copies in SY20,two dominant markers were developed and found to cosegregate with B1 in a population of 931 wheat accessions.All 77 awnless accessions harbored sequence variations in the B1 promoter regions similar to those of SY20 and thus carried multiple copies of the gene,whereas 15 randomly selected awned wheats carried only one copy.These results suggest that an increase in copy number of the B1 gene is associated with inhibition of awn length.
基金supported by the Funds of the State Key Laboratory of Frozen Soils Engineering,CAS(Grant No. SKLFSE-ZY-03)the National Key Natural Science Foundation of China(Grant No.50534040)+1 种基金the National Natural Science Foundation of China(Grant Nos. 40821001, 40801022,40801024,40801026,50976120,41001041)the Western Project Program of the Chinese Academy of Sciences(Grant No.KZCX2-XB2-10)
文摘With globe warming, road safety will change dramatically, especially within the Qinghai-Tibet Plateau permafrost regions. Because of higher elevation and better almospheric transparency, the Qinghai-Tibet Plateau has stronger radiation than other regions, which can change the daily variation of ground surface temperature on the Plateau. The awning measure （shading board） is one of the actively protected permafrost measures, which was adopted along the Qinghai-Tibet railway and highway and the Qing-Kang Highway in China. Field test results show that embankment surface month mean net radiation is 60-130 W/m2, but the value is below 20 W/m2 under the shading board, and the reducing level of naRn-al net radiation is 80%-90%. The shading board reduced the heat flow entering into the embankment by 80%,90% or more, with heat entering into the soil on the common embankment, but emitting from the embankment under the shading board. At the same time, ground surface temperature under the shading board is 6-8 ℃ lower than the exposed embankment. Test results show that the shading board measure can rapidly and effectively reduce net radiation and heat flow into the embankment, decrease embankment surface and interior temperature, effectively delay increase rate of soil temperature under globe warming, ensure stability and safety of the embankment, and guarantee unblocked road projects in cold and permafrost regions.
基金Youth Scientific Research Project of Anhui University of Chinese Medicine(No.2015qn038)Anhui University Scientific Research Innovation Platform Construction Project(No.2015TD033)。
文摘Objective:To evaluate the intervention effect of awn needle in the treatment of lumbar disc herniation through meta-analysis.Methods:In CNKI,Wanfang Data,PubMed,VIP and other databases,we searched the clinical observation studies on the treatment of patients with lumbar disc herniation with awn needle.The methodological quality of the included studies was evaluated using Cochrane 5.1.0 bias risk assessment criteria and Jadad scale.Revman 5.3 software was used for meta-analysis.Results:A total of 14 randomized controlled trials involving 1186 patients were included,with 595 in the awn needle treatment group and 591 in the control group.Meta-analysis showed that the awn needle treatment group was better than that of the control group in the total effective rate[RR=1.17;95%CI(1.12,1.22);Z=6.66;P<0.00001];the awn needle treatment group was better than the control group in ameliorating VAS score[WMD=-1.07,95%CI(-1.19,-0.95),Z=17.87,P<0.00001];the awn needle treatment group was better than the control group in ameliorating JOA score[WMD=3.18,95%CI(2.64,3.71),Z=11.57,P<0.00001];the awn needle treatment group was better than the control group in the amelioration of ADL score[SMD=2.44,95%CI(0.54,4.35),Z=2.52,P=0.01];the awn needle treatment group was better than the control group in the improvement of SLRT angle[WMD=12.71,95%CI(3.21,22.21),Z=2.62,P=0.009].Conclusion:Awn needle treatment can improve the total effective rate of patients with lumbar disc herniation,relieve the pain of patients,improve the straight leg elevation angle of patients,alleviate the disease development,relieve the symptoms,and improve the quality of life of patients.It is worthy of clinical application.
文摘In this paper, the effect of the thermosiphon, insulation board and awning in cooling the permafrost roadbed base was simulated numerically. The computed results were analysed and compared, some practical conclusion were presented.
基金This work was supported by the Ministry of Science and Technology of China （2013CBA01404 and 2012AA10A302）, the Chinese Academy of Sciences （XDA08020101）, the Ministry of Agriculture of China （2014ZX08001004-002-010）, the National Natural Science Foundation of China （31121063 and 31471159）, and the Science and Technology Commission of Shanghai Municipality （13QA1403900）.We thank Prof. Fangqing Guo and Dr. Xiaoling Shang for providing some cytokinin substances and Prof. Kang Chong for providing the vector pTCK 303. We thank Dr. Yining Liu for the LC/MS experiments, Jiqin Li and Xiaoyan Gao for the SEM experiments, and Xiaoshu Gao for the confocal microscopy experiments. No conflict of interest declared.
文摘A wide range of morphological and physiological traits have changed between cultivated rice Oryza sativa and wild rice Oryza rufipogon under domestication. Here, we report cloning of the An-2 gene, encoding the Lonely Guy Like protein 6 （OsLOGL6）, which catalyzes the final step of cytokinin synthesis in O. rufipogon. The near-isogenic line harboring a wild allele of An-2 in the genetic background of the awnless indica Guangluai 4 shows that An-2 promotes awn elongation by enhancing cell division, but decreases grain production by reducing grains per panicle and tillers per plant. We reveal that a genetic variation in the An-2 locus has a large impact on reducing awn length and increasing tiller and grain numbers in domesticated rice. Analysis of gene expression patterns suggests that An-1 reg- ulates the formation of awn primordial, and An-2 promotes awn elongation. Nucleotide diversity of the An-2 locus in cultivated rice was found to be significantly reduced compared with that of wild rice, suggesting that the An-2 locus was subjected to artificial selection. We therefore propose that the selection of genetic variation in An-2 was due to reduced awn length and increased grain yield in cultivated rice.
基金This work was supported by the National Natural Science Foundation of China(92035302 and 31871632 to Z.L.)the National Key Research and Development Program of China(2016YFD0100303 and 2016YFD0101803 to Z.L.)the Chinese Universities Scientific Fund(2021TC065 to Z.L.).
文摘Loss of the awn in some cereals including sorghum is a key transition during cereal domestication or improvement that has facilitated grain harvest and storage.The genetic basis for the loss of awn in sorghum during domestication or improvement remains unknown.Here,we identified a transcription factor gene awn1 encoding an ALOG domain,which is responsible for awn loss during sorghum domestication or improvement.awn1 arose from a gene duplication from chromosome 10 that translocated to chromosome 3,recruiting a new promoter from the neighbouring intergenic region filled with"noncoding DNA",and recreating the first exon and intron.The awn1 acquires high expr`ession after duplication and represses the elongation of awns in domesticated sorghum.Comparative mapping revealed a high collinearity at awn1 paralog locus on chromosome 10 across cereals and awn growth and development was successfully reactivated on the rice spikelet by inactivating rice awn1 orthologue.Further RNA-seq and DAP-seq revealed that as a transcription repressor,AWN1 directly bound to the motif in the regulatory regions from three MADS genes related to flower development and two genes DL and LKS2 for the development of awn,downregulated the expressions of these genes,and then repressed the elongation of awn.The preexistence of regulatory elements in the neighbouring intergenic region of awn1 before domestication signified that noncoding DNA may serve as a treasure trove for evolution during adaptation to a changing world.Our results supported that gene duplication can promptly drive the evolution of gene regulatory network.
基金supported by the National Key Research and Development Program of China(2022YFF1003401)the National Natural Science Foundation of China(31991210)the National Natural Science Foundation of China(32172069).
文摘Awns are important morphological markers for wheat and exert a strong physiological effect on wheat yield.The awn elongation suppressor B1 has recently been cloned through association and linkage analysis in wheat.However,the mechanism of awn inhibition centered around B1 remains to be clarified.Here,we identified an allelic variant in the coding region of B1 through analysis of re-sequencing data;this variant causes an amino acid substitution and premature termination,resulting in a long-awn phenotype.Transcriptome analysis indicated that B1 inhibited awn elongation by impeding cytokinin-and auxinpromoted cell division.Moreover,B1 directly repressed the expression of TaRAE2 and TaLks2,whose orthologs have been reported to promote awn development in rice or barley.More importantly,we found that TaTCP4 and TaTCP10 synergistically inhibited the expression of B1,and a G-to-A mutation in the B1 promoter attenuated its inhibition by TaTCP4/10.Taken together,our results reveal novel mechanisms of awn development and provide genetic resources for trait improvement in wheat.
基金supported by the National Key Basic Research Program of China (2010CB125904 and 2004CB117201) the National HighTechnology Research and Development Program of China (2006A- A10Z158)
文摘Awnness is a key trait in rice domestication, yet no studies have been conducted on fine mapping or association mapping of the rice awn gene. In this study, we investigated the awnness and genotype of a core collection of 303 cultivated rice varieties and a BC5F2 segregating population of 200 individuals. Combining association and linkage analyses, we mapped the awnness related genes to chromosome 4. Primary association analysis using 24 SSR markers revealed five loci significantly associated with awnness on chromosome 4. The associated markers cover previously identified regions. Fine association mapping was conducted using another 29 markers within a 4-Mb region, covering the associated marker in34, which is close to the awn gene Awn4.1. Seven associated markers were revealed, distributed over an 870-kb region. Combining the fine association mapping and linkage analysis of awnness in the 200 BC5F2 segregating population, we finally identified a 330-kb region as the candidate region for Awn4.1. The results indicate that combining association mapping and linkage mapping provides an efficient and precise approach to both genome-wide mapping and fine mapping of rice genes.
