It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has s...It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has summarized genetic diversity and protection achievements of DXWR from many aspects like varied conservations, years, generations, other species of wild rice and cultivated rice. In this study, a u- nified and scientific evaluation system of genetic diversity is encouraged to be built and suggestions on research prospect and ecological conservation of DXWR genetic diversity have been proposed.展开更多
Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of ...Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of 36 parents and 423 rice lines from 68 hybrid groups were investigated at seedling stage under low tempera- ture and sparse light conditions in field. There were 10 parent accessions with strong cold tolerance of level 1. Among them, 3 were common wild rice accessions; 4 were japonica rice cultivars; 2 were indica rice; 1 was offspring from hybrid be- tween indica and japonica.There were 33 lines with strong cold tolerance of level 1 from the hybrid groups of common wild rice,and 15 from the hybrid groups of IRBB5, and only 3 from the hybrid groups of BPHR96. There were abundant cold tolerance resources in rice germplasm. It was feasible to develop cold tolerance cul- tivars from the hybrids among common wild rice, japonica cultivars and indica culti- vars.展开更多
When Elizabethan＇s were trained to read and write, the handwriting they first learned was ＂Secretary＂ （or ＂Secretarial＂） hand, reflecting the style used by monks and scribes well back into the Middle Ages. Only...When Elizabethan＇s were trained to read and write, the handwriting they first learned was ＂Secretary＂ （or ＂Secretarial＂） hand, reflecting the style used by monks and scribes well back into the Middle Ages. Only in the mid-1500s did an alternative hand called ＂Italic＂ （or ＂Italianate＂） slowly begin to be adopted as a second hand, reflecting handwriting used on the continent, and Italic was rarer than Secretary until well after 1600. Today, extant Elizabethan handwriting samples normally show each person used both hand styles, and where only one hand is extant for a given person, it is usually a Secretary hand. Thus, it＇s a surprise that two noblemen, the great William Cecil, Lord Burghley, and his son-in-law Edward DeVere, the 17th Earl of Oxford, are each assumed to have only Italic hand samples among their voluminous collections of handwriting. Did they not learn and never use Secretary hands, or is it that any Secretary hands in their documents are simply presumed to be written by clerks？ This article begins with questioning whether the two men really were limited to Italic hands, fmds a few plausible Secretary hand samples for one of them （possibly for both）, reconstructs a hypothetical Italic alphabet for him, and nominates many candidate manuscripts （MSS, singular MS） for having been written or contributed to by him, some of which may be relevant to Shakespeare studies. Other subjects touched on are calligraphy, a clerk （or amanuensis）, and griffe de notaire （literally a ＂notary＇s scratch＂, or identifying scribble）.展开更多
[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. ...[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.展开更多
Bacterial leaf streak （BLS） of rice, caused by Xanthomonas oryzae pv. oryzicola （Xoc） is a worldwide destructive disease. Development of resistant varieties is considered to be one of the most effective and eco-fr...Bacterial leaf streak （BLS） of rice, caused by Xanthomonas oryzae pv. oryzicola （Xoc） is a worldwide destructive disease. Development of resistant varieties is considered to be one of the most effective and eco-friendly ways to control the disease. However, only a few genes/QTLs having resistance to BLS have been identified in rice until now. In the present study, we have identified and primarily mapped a BLS-resistance gene, blsl, from a rice line DP3, derived from the wild rice species Oryza rufipogon Griff. A BC2F2 （9311/DP3//9311） population was constructed to map BLS-resistance gene in the rice line DP3. The segregation of the resistant and susceptible plants in BCzFz in 1：3 ratio （Z2=0.009, Z20 05,1=3.84, P〉0.05）, suggested that a recessive gene confers BLS resistance in DP3. In bulked segregant analysis （BSA）, two SSR markers RM8116 and RM584 were identified to be polymorphic in resistant and susceptible DNA bulks. For further mapping the resistance gene, six polymorphic markers around the target region were applied to analyze the genotypes of the BC2F2 individuals. As a result, the BLS-resistant gene, designated as blsl, was mapped in a 4.0-cM region flanked by RM587 and RM510 on chromosome 6.展开更多
Rice planthoppers,including brown planthopper(BPH)and white-backed planthopper(WBPH),are the most destructive pests in Asian rice cultivation regions.Planthopper resistance genes that have been mapped and characterize...Rice planthoppers,including brown planthopper(BPH)and white-backed planthopper(WBPH),are the most destructive pests in Asian rice cultivation regions.Planthopper resistance genes that have been mapped and characterized advance our understanding of underlying resistance mechanisms and facilitate the breeding of resistant varieties,thereby contributing to an efficient pest management strategy.In this study,a novel resistance gene Bph38 derived from the wild rice species Oryza rufipogon Griff.was found to confer high resistance to BPH and WBPH.Conventional mapping was performed to identify regions associated with BPH and WBPH resistance,and two mapping efforts led to the same region on chromosome 4 flanked by markers RM16563 and RM16763.Bulked-segregant analysis and next-generation sequencing were performed using the same population to detect the resistance gene.Conventional mapping narrowed the region to a 12.3-Mb segment,and fine mapping using BC1 F2 recombinants identified a 79-kb segment flanked by markers YM112 and YM190.Near-isogenic lines(NILs)carrying Bph38 in the 9311(indica)and BR54(japonica)genetic backgrounds were developed by crossing and backcrossing with marker-assisted selection.The agronomic traits and BPH and WBPH resistance of the NILs were similar to those of the recurrent parents.Mandatory feeding and host-choice tests revealed that Bph38 showed both antibiotic and antixenotic effects in both insects,with stronger effects in indica-background lines.Further fine mapping and characterization of the major gene may result in map-based cloning of the gene and allow its application in breeding insectresistant rice varieties.展开更多
Assessment of genetic diversity is an essential component in germplasm characterization and conservation.There are three wild rice species in Hainan Province,including Oryza rufipogon Griff.In order to detect the gene...Assessment of genetic diversity is an essential component in germplasm characterization and conservation.There are three wild rice species in Hainan Province,including Oryza rufipogon Griff.In order to detect the genetic diversity of different populations of Oryza rufipogon in Hainan,ISSR(inter-simple sequence repeat)and SSR(simple sequence repeat)markers were used to investigate 180 accessions from six localities in Hainan.Fourteen ISSR primers amplified 185 alleles with 171(92.43%)polymorphic,the number of alleles ranged from 8 to 17,with an average of 13.14 alleles per locus.Thirty-eight pairs of SSR primers used in this study amplified 213 alleles with 190(89.20%)polymorphic,the number of alleles ranged from 2 to 14,with an average of 5.66 alleles per locus.Both ISSR and SSR analyses revealed a high level of genetic diversity in the wild populations.The population with the highest genetic diversity is Wanning(WN),and the population with lowest genetic diversity is Wenchang(WC).The results of a UPGMA cluster using the NTSYS program showed that each population has a low degree of genetic differentiation.Furthermore,the Mantel test revealed that the genetic similarities detected by ISSR and SSR were significantly correlated(r=0.8634,t=93.67)when detecting genetic diversity at the species level.The two molecular marker systems were able to determine the genetic diversity among Oryza rufipogon,and the two groups of indexes obtained by using the two markers have a high level of consistency.展开更多
Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines（ILs）,which were der...Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines（ILs）,which were derived from a cross between an elite indica cultivar Teqing and an accession of common wild rice（Oryza rufipogon Griff.）.Substantial variation was observed for four traits including salt tolerance score（STS）, relative root dry weight（RRW）,relative shoot dry weight（RSW） and relative total dry weight（RTW）.STS was significantly positively correlated with all other three traits.A total of 15 putative quantitative trait loci（QTLs） associated with these four traits were detected using single-point analysis,which were located on chromosomes 1,2,3,6,7,9 and 10 with 8%-26%explaining the phenotypic variance.The O. rufipogon-derived alleles at 13 QTLs（86.7%） could improve the salt tolerance in the Teqing background.Four QTL clusters affecting RRW, RSW and RTW were found on chromosomes 6,7,9 and 10,respectively.Among these four QTL clusters,a major cluster including three QTLs （qRRWIO,qRSWIO and qRTWIO） was found near the maker RM271 on the long arm of chromosome 10,and the O.rufipogon-derived alleles at these three loci increased RRW,RSW and RTW with additive effects of 22.7%,17.3%and 18.5%,respectively,while the phenotypic variance explained by these three individual QTLs for the three traits varied from 19%to 26%.In addition,several salt tolerant ILs were selected and could be used for identifying and utilizing favorable salt tolerant genes from common wild rice and used in the salt tolerant rice breeding program.展开更多
基金Supported by National Natural Science Foundation of China(30960189)the National Public Benefit(Agricultural)Research Foundation of China(201103007)+1 种基金Special Funds for Establishment of Modern Agricultural and Industrial Technology System(NXCYTY-01)Project supported by Jiangxi Academy of Agricultural Science for Innovation(2010CQN008)~~
文摘It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has summarized genetic diversity and protection achievements of DXWR from many aspects like varied conservations, years, generations, other species of wild rice and cultivated rice. In this study, a u- nified and scientific evaluation system of genetic diversity is encouraged to be built and suggestions on research prospect and ecological conservation of DXWR genetic diversity have been proposed.
基金Supported by Guangxi Natural Science Foundation Item,China(2013GXNSFBA019-066)Guangxi Science Research and Technology Development Project,China(Guikezhong14121001-2-4)Nanning Municipal Science Research and Technology Development Plan Item,China(20132304)~~
文摘Low temperature and sparse light in early spring is one of the factors causing reduction for rice production. So it is important to develop cold tolerance cultivars. In the present study, cold tolerance characters of 36 parents and 423 rice lines from 68 hybrid groups were investigated at seedling stage under low tempera- ture and sparse light conditions in field. There were 10 parent accessions with strong cold tolerance of level 1. Among them, 3 were common wild rice accessions; 4 were japonica rice cultivars; 2 were indica rice; 1 was offspring from hybrid be- tween indica and japonica.There were 33 lines with strong cold tolerance of level 1 from the hybrid groups of common wild rice,and 15 from the hybrid groups of IRBB5, and only 3 from the hybrid groups of BPHR96. There were abundant cold tolerance resources in rice germplasm. It was feasible to develop cold tolerance cul- tivars from the hybrids among common wild rice, japonica cultivars and indica culti- vars.
文摘When Elizabethan＇s were trained to read and write, the handwriting they first learned was ＂Secretary＂ （or ＂Secretarial＂） hand, reflecting the style used by monks and scribes well back into the Middle Ages. Only in the mid-1500s did an alternative hand called ＂Italic＂ （or ＂Italianate＂） slowly begin to be adopted as a second hand, reflecting handwriting used on the continent, and Italic was rarer than Secretary until well after 1600. Today, extant Elizabethan handwriting samples normally show each person used both hand styles, and where only one hand is extant for a given person, it is usually a Secretary hand. Thus, it＇s a surprise that two noblemen, the great William Cecil, Lord Burghley, and his son-in-law Edward DeVere, the 17th Earl of Oxford, are each assumed to have only Italic hand samples among their voluminous collections of handwriting. Did they not learn and never use Secretary hands, or is it that any Secretary hands in their documents are simply presumed to be written by clerks？ This article begins with questioning whether the two men really were limited to Italic hands, fmds a few plausible Secretary hand samples for one of them （possibly for both）, reconstructs a hypothetical Italic alphabet for him, and nominates many candidate manuscripts （MSS, singular MS） for having been written or contributed to by him, some of which may be relevant to Shakespeare studies. Other subjects touched on are calligraphy, a clerk （or amanuensis）, and griffe de notaire （literally a ＂notary＇s scratch＂, or identifying scribble）.
基金partially supported by National Natural Science Foundation of China(30860120,30900781)Science and Technology Projects of Jiangxi Education Department(GJJ09464)Natural Science Foundation of Jiangxi(2008GQN0059)~~
文摘[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.
基金supported by the Science Foundation of Guangxi University, China (XDZ110082)the National Natural Science Foundation of China (31000703)+2 种基金the Guangxi Science and Technology Projects, China (1123001-3B)the Guangxi Science Foundation of China (0833078)the Fundamental Research Funds for Guangxi Academy of Agricultural Sciences, China (200801Z and 200918J)
文摘Bacterial leaf streak （BLS） of rice, caused by Xanthomonas oryzae pv. oryzicola （Xoc） is a worldwide destructive disease. Development of resistant varieties is considered to be one of the most effective and eco-friendly ways to control the disease. However, only a few genes/QTLs having resistance to BLS have been identified in rice until now. In the present study, we have identified and primarily mapped a BLS-resistance gene, blsl, from a rice line DP3, derived from the wild rice species Oryza rufipogon Griff. A BC2F2 （9311/DP3//9311） population was constructed to map BLS-resistance gene in the rice line DP3. The segregation of the resistant and susceptible plants in BCzFz in 1：3 ratio （Z2=0.009, Z20 05,1=3.84, P〉0.05）, suggested that a recessive gene confers BLS resistance in DP3. In bulked segregant analysis （BSA）, two SSR markers RM8116 and RM584 were identified to be polymorphic in resistant and susceptible DNA bulks. For further mapping the resistance gene, six polymorphic markers around the target region were applied to analyze the genotypes of the BC2F2 individuals. As a result, the BLS-resistant gene, designated as blsl, was mapped in a 4.0-cM region flanked by RM587 and RM510 on chromosome 6.
基金supported by National Key Research and Development Program of China(2016YFD0100600)the National Program on Research and Development of Transgenic Plants(2014ZX0800911B)+2 种基金the National Natural Science Foundation of China(31160276 and 31560423)the Guangxi Innovation-Driven Development Special Funding Project(Guike-AA17204070)the State Key Laboratory of Hybrid Rice(KF201905)。
文摘Rice planthoppers,including brown planthopper(BPH)and white-backed planthopper(WBPH),are the most destructive pests in Asian rice cultivation regions.Planthopper resistance genes that have been mapped and characterized advance our understanding of underlying resistance mechanisms and facilitate the breeding of resistant varieties,thereby contributing to an efficient pest management strategy.In this study,a novel resistance gene Bph38 derived from the wild rice species Oryza rufipogon Griff.was found to confer high resistance to BPH and WBPH.Conventional mapping was performed to identify regions associated with BPH and WBPH resistance,and two mapping efforts led to the same region on chromosome 4 flanked by markers RM16563 and RM16763.Bulked-segregant analysis and next-generation sequencing were performed using the same population to detect the resistance gene.Conventional mapping narrowed the region to a 12.3-Mb segment,and fine mapping using BC1 F2 recombinants identified a 79-kb segment flanked by markers YM112 and YM190.Near-isogenic lines(NILs)carrying Bph38 in the 9311(indica)and BR54(japonica)genetic backgrounds were developed by crossing and backcrossing with marker-assisted selection.The agronomic traits and BPH and WBPH resistance of the NILs were similar to those of the recurrent parents.Mandatory feeding and host-choice tests revealed that Bph38 showed both antibiotic and antixenotic effects in both insects,with stronger effects in indica-background lines.Further fine mapping and characterization of the major gene may result in map-based cloning of the gene and allow its application in breeding insectresistant rice varieties.
文摘Assessment of genetic diversity is an essential component in germplasm characterization and conservation.There are three wild rice species in Hainan Province,including Oryza rufipogon Griff.In order to detect the genetic diversity of different populations of Oryza rufipogon in Hainan,ISSR(inter-simple sequence repeat)and SSR(simple sequence repeat)markers were used to investigate 180 accessions from six localities in Hainan.Fourteen ISSR primers amplified 185 alleles with 171(92.43%)polymorphic,the number of alleles ranged from 8 to 17,with an average of 13.14 alleles per locus.Thirty-eight pairs of SSR primers used in this study amplified 213 alleles with 190(89.20%)polymorphic,the number of alleles ranged from 2 to 14,with an average of 5.66 alleles per locus.Both ISSR and SSR analyses revealed a high level of genetic diversity in the wild populations.The population with the highest genetic diversity is Wanning(WN),and the population with lowest genetic diversity is Wenchang(WC).The results of a UPGMA cluster using the NTSYS program showed that each population has a low degree of genetic differentiation.Furthermore,the Mantel test revealed that the genetic similarities detected by ISSR and SSR were significantly correlated(r=0.8634,t=93.67)when detecting genetic diversity at the species level.The two molecular marker systems were able to determine the genetic diversity among Oryza rufipogon,and the two groups of indexes obtained by using the two markers have a high level of consistency.
基金supported by the Project of Conservation and Utilization of Agro-Wild Plants of the Ministry of Agriculture of China and Special Fund for Agro-scientific Research in the Public Interest(No.201003021)
文摘Soil salinity is one of the major abiotic stresses affecting plant growth and crop production.In the present study,salt tolerance at rice seedling stage was evaluated using 87 introgression lines（ILs）,which were derived from a cross between an elite indica cultivar Teqing and an accession of common wild rice（Oryza rufipogon Griff.）.Substantial variation was observed for four traits including salt tolerance score（STS）, relative root dry weight（RRW）,relative shoot dry weight（RSW） and relative total dry weight（RTW）.STS was significantly positively correlated with all other three traits.A total of 15 putative quantitative trait loci（QTLs） associated with these four traits were detected using single-point analysis,which were located on chromosomes 1,2,3,6,7,9 and 10 with 8%-26%explaining the phenotypic variance.The O. rufipogon-derived alleles at 13 QTLs（86.7%） could improve the salt tolerance in the Teqing background.Four QTL clusters affecting RRW, RSW and RTW were found on chromosomes 6,7,9 and 10,respectively.Among these four QTL clusters,a major cluster including three QTLs （qRRWIO,qRSWIO and qRTWIO） was found near the maker RM271 on the long arm of chromosome 10,and the O.rufipogon-derived alleles at these three loci increased RRW,RSW and RTW with additive effects of 22.7%,17.3%and 18.5%,respectively,while the phenotypic variance explained by these three individual QTLs for the three traits varied from 19%to 26%.In addition,several salt tolerant ILs were selected and could be used for identifying and utilizing favorable salt tolerant genes from common wild rice and used in the salt tolerant rice breeding program.
