Although great accomplishments of in situ conservation have been made during the last decade throughout the world, there is an urgent need to conduct more targeted research to explore many basic questions about crop w...Although great accomplishments of in situ conservation have been made during the last decade throughout the world, there is an urgent need to conduct more targeted research to explore many basic questions about crop wild relatives (CWR) in situ conservation such as how to better identify and manage the target in situ conservation populations of CWR. In this study, we performed an extensive field investigation of 201 natural populations or habitats of O. rufipogon, a seriously endangered wild progenitor of cultivated rice in China. Our updated information suggests that: 1) the majority of the natural populations have been extinct throughout China, which leads to serious fragmentation of the population system as a whole;and 2) the survived populations have become small in size and thus fragmented within the population as a result of the loss of subpopulations. To assess the relationships between the biodiversity education and conservation of wild rice, we employed participatory approaches in the field investigation. Our data indicate that the continuous rapid decline of biodiversity education seemed closely related to the extinction of wild rice germplasm. These findings imply the potential necessity and huge challenge for making in situ conservation plans in the future. By means of our understanding of ecogeography, sociology and culture, and population genetics of the species, we propose a strategy for selecting in situ conservation locations as well as priority sites for establishing in situ conservation practices in China.展开更多
Two populations of Dongxiang wild rice （Oryza rufipogon）, Shuitaoshu and Dongtangshang, were crossed with five male sterile rice lines with different cytoplasmic backgrounds （B06S, Zhenshan 97A, Xieqingzao A, Zhong...Two populations of Dongxiang wild rice （Oryza rufipogon）, Shuitaoshu and Dongtangshang, were crossed with five male sterile rice lines with different cytoplasmic backgrounds （B06S, Zhenshan 97A, Xieqingzao A, Zhong 9A, and Yuetai A）, and the seed setting rate of the F1 was used to judge the fertility restoration ability in the Dongxiang wild rice. With P1, F1, P2, and F2 populations as materials, the Akaike＇s Information Criterion （AIC） was used to identify the major genes affecting quantitative traits, and when the major genes existed, the genetic effects of the major gene and the polygene and their genetic variance were estimated through segregation analysis. The seed setting rates of the F1 generation varied from 45.98% to 76.57%, suggesting that the Dongxiang wild rice had the fertility restoration ability. One major gene plus polygene mixed inheritance model was the most fitted genetic model for this trait in all the F2 populations. The heritability values of the major genes varied from 56.63% to 88.29% and those of the polygenes from 2.74% to 30.97%, and the total heritability values were from 63.17% to 94.01%. The major gene inheritance of the combination Zhong 9A/Dongtangshang was controlled by the additive effect without dominant effect, and the other nine combinatfons were by the completely dominant inheritance.展开更多
This study was conducted to develop and characterize a novel cytoplasmic male sterile （CMS） source which was identified from Dongxiang wild rice （Oryza rufipogon） by crossing Dongxiang wild rice as female with Zho...This study was conducted to develop and characterize a novel cytoplasmic male sterile （CMS） source which was identified from Dongxiang wild rice （Oryza rufipogon） by crossing Dongxiang wild rice as female with Zhongzao 35, an indica inbred variety, as male and continuous backcrossing with Zhongzao 35. Observation under optical microscope manifested that this novel CMS belonged to typical abortion type with less pollen compared with wild abortive type cytoplasm （CMS-WA）. Sequential planting showed that this novel CMS has complete and stable male sterility. Testcross experiment showed that all the 24 tested materials including maintainer and restorer lines of CMS-WA and Honglian type cytoplasm （CMS-HL） and other indica inbred varieties are the maintainers with complete maintaining ability, suggesting that this novel CMS has fertility restoration totally different from CMS-WA and CMS-HL and belongs to a novel type of CMS. So far, we only discovered a unique fertility restoration source for this novel CMS. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. Prospect for application of this novel CMS system in hybrid rice breeding was also discussed.展开更多
Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice,which is one of the main constrains for the utilization of heterosis between indica and japonica.Six loci controlling the po...Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice,which is one of the main constrains for the utilization of heterosis between indica and japonica.Six loci controlling the pollen sterility of F1 between indica and japonica have been identified from previous studies.Neutral alleles at each locus are potential to overcome the F1 pollen sterility associated with the locus.Therefore,exploitation and utilization of neutral alleles are of significant importance.The present research was based on fine mapping of the F1 pollen-sterility gene Sb and the abundant genetic diversity of Oryza rufipogon Griff.indigenous to Gaozhou,Guangdong Province(referred to as Gaozhou wild rice).Crosses were made using Taichung65(with the genotype of SbjSbj and referred to as E1) and its near-isogenic line of F1 pollen sterility gene Sb(with the genotype of SbiSbi,E2) as female parents,and 12 different accessions of Gaozhou wild rice as male parents.F1 pollen fertility was examined to identify the materials having the neutral alleles at the F1 pollen-sterility locus.Segregation of 4 molecular markers tightly linked with the Sb locus was analyzed in the F2 populations derived from the F1s carrying the neutral gene.The pollen fertility related to the 3 genotypes of the molecular markers was also checked by statistical test to determine whether it was consistent with the hypothesis.The results showed that the pollen fertility of two F1s from one accession of Gaozhou wild rice(GZW099) with E1 and E2 was(89.22±1.07)% and(85.65±1.05)%,respectively.Both of them were fertile and showed no significant difference by t-test.Segregation of the 3 genotypes of the 4 molecular markers followed the expected Mendelian ratio(1:2:1) in the F2 populations.There was no significant difference for the averaged pollen fertility of the plants related to the 3 genotypes,suggesting that no interaction exists between the alleles at the Sb locus in GZW099 and Taichung65 or E2.Evidentially,GZW099 carried the neutral gene(named SbnSbn) at the Sb locus,which provides valuable theoretical basis and resources for further studying and overcoming the sterility of indica-japonica hybrids.展开更多
文摘Although great accomplishments of in situ conservation have been made during the last decade throughout the world, there is an urgent need to conduct more targeted research to explore many basic questions about crop wild relatives (CWR) in situ conservation such as how to better identify and manage the target in situ conservation populations of CWR. In this study, we performed an extensive field investigation of 201 natural populations or habitats of O. rufipogon, a seriously endangered wild progenitor of cultivated rice in China. Our updated information suggests that: 1) the majority of the natural populations have been extinct throughout China, which leads to serious fragmentation of the population system as a whole;and 2) the survived populations have become small in size and thus fragmented within the population as a result of the loss of subpopulations. To assess the relationships between the biodiversity education and conservation of wild rice, we employed participatory approaches in the field investigation. Our data indicate that the continuous rapid decline of biodiversity education seemed closely related to the extinction of wild rice germplasm. These findings imply the potential necessity and huge challenge for making in situ conservation plans in the future. By means of our understanding of ecogeography, sociology and culture, and population genetics of the species, we propose a strategy for selecting in situ conservation locations as well as priority sites for establishing in situ conservation practices in China.
文摘Two populations of Dongxiang wild rice （Oryza rufipogon）, Shuitaoshu and Dongtangshang, were crossed with five male sterile rice lines with different cytoplasmic backgrounds （B06S, Zhenshan 97A, Xieqingzao A, Zhong 9A, and Yuetai A）, and the seed setting rate of the F1 was used to judge the fertility restoration ability in the Dongxiang wild rice. With P1, F1, P2, and F2 populations as materials, the Akaike＇s Information Criterion （AIC） was used to identify the major genes affecting quantitative traits, and when the major genes existed, the genetic effects of the major gene and the polygene and their genetic variance were estimated through segregation analysis. The seed setting rates of the F1 generation varied from 45.98% to 76.57%, suggesting that the Dongxiang wild rice had the fertility restoration ability. One major gene plus polygene mixed inheritance model was the most fitted genetic model for this trait in all the F2 populations. The heritability values of the major genes varied from 56.63% to 88.29% and those of the polygenes from 2.74% to 30.97%, and the total heritability values were from 63.17% to 94.01%. The major gene inheritance of the combination Zhong 9A/Dongtangshang was controlled by the additive effect without dominant effect, and the other nine combinatfons were by the completely dominant inheritance.
基金supported by the Key Program for Scienceand Technology of Jiangxi ProvinceChina(Grant No.20114ABF03101)+1 种基金the Program of Advantage Group forInnovation of Science and Technology of Jiangxi ProvinceChina(Grant No.20115BCB29019)
文摘This study was conducted to develop and characterize a novel cytoplasmic male sterile （CMS） source which was identified from Dongxiang wild rice （Oryza rufipogon） by crossing Dongxiang wild rice as female with Zhongzao 35, an indica inbred variety, as male and continuous backcrossing with Zhongzao 35. Observation under optical microscope manifested that this novel CMS belonged to typical abortion type with less pollen compared with wild abortive type cytoplasm （CMS-WA）. Sequential planting showed that this novel CMS has complete and stable male sterility. Testcross experiment showed that all the 24 tested materials including maintainer and restorer lines of CMS-WA and Honglian type cytoplasm （CMS-HL） and other indica inbred varieties are the maintainers with complete maintaining ability, suggesting that this novel CMS has fertility restoration totally different from CMS-WA and CMS-HL and belongs to a novel type of CMS. So far, we only discovered a unique fertility restoration source for this novel CMS. Inheritance analysis showed that the fertility restoration of this CMS was governed by three pairs of independent dominant genes. Prospect for application of this novel CMS system in hybrid rice breeding was also discussed.
基金Supported by the Joint Funds of the National Natural Science Foundation of ChinaGuangdong Province(Grant No.U0631003)Natural Science Foundation of Guangdong Province(Grant No.5300831)
文摘Pollen sterility is commonly found in the intra-specific hybrids of indica and japonica rice,which is one of the main constrains for the utilization of heterosis between indica and japonica.Six loci controlling the pollen sterility of F1 between indica and japonica have been identified from previous studies.Neutral alleles at each locus are potential to overcome the F1 pollen sterility associated with the locus.Therefore,exploitation and utilization of neutral alleles are of significant importance.The present research was based on fine mapping of the F1 pollen-sterility gene Sb and the abundant genetic diversity of Oryza rufipogon Griff.indigenous to Gaozhou,Guangdong Province(referred to as Gaozhou wild rice).Crosses were made using Taichung65(with the genotype of SbjSbj and referred to as E1) and its near-isogenic line of F1 pollen sterility gene Sb(with the genotype of SbiSbi,E2) as female parents,and 12 different accessions of Gaozhou wild rice as male parents.F1 pollen fertility was examined to identify the materials having the neutral alleles at the F1 pollen-sterility locus.Segregation of 4 molecular markers tightly linked with the Sb locus was analyzed in the F2 populations derived from the F1s carrying the neutral gene.The pollen fertility related to the 3 genotypes of the molecular markers was also checked by statistical test to determine whether it was consistent with the hypothesis.The results showed that the pollen fertility of two F1s from one accession of Gaozhou wild rice(GZW099) with E1 and E2 was(89.22±1.07)% and(85.65±1.05)%,respectively.Both of them were fertile and showed no significant difference by t-test.Segregation of the 3 genotypes of the 4 molecular markers followed the expected Mendelian ratio(1:2:1) in the F2 populations.There was no significant difference for the averaged pollen fertility of the plants related to the 3 genotypes,suggesting that no interaction exists between the alleles at the Sb locus in GZW099 and Taichung65 or E2.Evidentially,GZW099 carried the neutral gene(named SbnSbn) at the Sb locus,which provides valuable theoretical basis and resources for further studying and overcoming the sterility of indica-japonica hybrids.
