The analysis of wild rice cell structures,tissues,organs,and other morphological characteristics and the development of identification markers for wild rice are the basis for identifying the origins and evolution of p...The analysis of wild rice cell structures,tissues,organs,and other morphological characteristics and the development of identification markers for wild rice are the basis for identifying the origins and evolution of prehistorical rice agriculture.However,contemporary wild rice strains are often subject to gene introgression from domesticated rice cultivated by humans during the evolutionary process,which may affect the accuracy of wild rice identification markers.This means that how to eliminate the effects of gene introgression from domesticated rice and other plants on the identification of origin markers,and the purification of the morphological characteristics of wild rice have become critical in research to identify the origin of rice.In this study,we compared and analysed the phytolith morphologies of three common wild rice species(Oryza rufipogon Griff.)from various habitats and one species of ectopically preserved homozygous common wild rice after six consecutive generations of self-crossing.We found that the morphology of the bulliform phytolith in the homozygous wild rice with reduced domestication gene introgression had three significant differences compared with native wild rice:(1)an overall reduction in size(body length decreased from 41.9μm in VLnativeto 38.6μm in VLhomozygous);(2)an increase in the proportion of the long-stalked phenotype,with the ratio of B/A decreasing from 1.22±0.47 in B/Anativeto 0.92±0.30 in B/Ahomozygous;and(3)a decrease in the number of fish-scale decorations,with the proportion of bulliform phytoliths with≥9 fish-scale decorations reduced from 53.4%in native wild rice to 37.2%in homozygous wild rice.Thus,this study provides a reliable reference for the identification of rice origins using rice phytolith morphology.展开更多
The genetic similarity and genetic difference among improved japonica rice varieties from different countries （or regions and organizations） were detected. The aim is to provide genetic basis to the breeding of japo...The genetic similarity and genetic difference among improved japonica rice varieties from different countries （or regions and organizations） were detected. The aim is to provide genetic basis to the breeding of japonica rice varieties. The genetic similarity and cluster of 313 improved japonica varieties from 20 countries （or regions and organizations） were analyzed using the SSR marker. With 34 SSR primers which were polymorphic and uniformly distributed in rice genome, totally 198 alleles were detected among these improved varieties with the average number of alleles per pair of primers of 5.8235. RM320, RM531, RM1, RM21, and RM336 located more alleles, which were 16, 13, 12, 10, and 10 respectively. RM320, RM336, RM286, RM531, and RM21 showed higher genetic diversity indexes, which were 2.3668, 2.0041, 1.9684, 1.9508, and 1.7203, respectively. The genetic similarity for improved japonica varieties among different countries （or regions and organizations） were ranged from 0.279 to 0.918, and the mean value was 0.653. The rice varieties from countries whose latitude and geography position were all nearer were clustered together with higher genetic similarity indexes. The rice varieties from countries who had more different latitude and far geography position were clustered separately with lower genetic similarity indexes. The results indicated the genetic similarity indexes among improved japonica varieties had a close relationship with the geographical position, especially with the latitude.展开更多
cies of cultivated rice in ancient China is possibly more northward than in the modern times. The earliest rice grains unearthed from the Neolithic sites existed along the lower and middle reaches of the Yangtze River...cies of cultivated rice in ancient China is possibly more northward than in the modern times. The earliest rice grains unearthed from the Neolithic sites existed along the lower and middle reaches of the Yangtze River. The later ones were found in Yunnan Province, South China and along the Yellow River reaches. Primitive rice cropping in the Taihu Lake region which is on the lower reach of the Yangtze River has already a 6,000-7,000 years history and the primitive tribes growing rice there are ancestors of the Yue Nationality since the beginning of the history, hence the Yue Nationality is the most important one for rice cropping in China. During the periods of Spring-Autumn and Warring States to Qin and Han Dynasties (from 722 B.C. to A.D.220 ), Yue people disseminated rice to Japan, Korea and other Southeast Asian countries by sea. In the period of over 3,000 years since the recorded history,the rice development in China has experienced changes from north to south and from south to north. As Chinese c展开更多
Microsatellite markers and morphological characteristics were used to explore the genetic diversity and possible origin of weedy rice in Taizhou City, Jiangsu Province, China. Fifty-two weedy rice (Oryza sativa L.) ac...Microsatellite markers and morphological characteristics were used to explore the genetic diversity and possible origin of weedy rice in Taizhou City, Jiangsu Province, China. Fifty-two weedy rice (Oryza sativa L.) accessions were compared with two wild rice, four hybrid rice and five cultivars using 22 simple sequence repeat (SSR) primer pairs. A total of 107 fragments were amplified, averaging 5.6 alleles per primer pair. The polymorphic index content (PIC) values ranged from 0.3077 to 0.7951, averaging at 0.5870. The average genetic distance of all samples ranged from 0.02 to 0.46 with an average of 0.262. The genetic distance among Taizhou weedy rice ranged from 0.03 to 0.44 with an average of 0.224. Cluster analysis showed that all the weedy rice accessions from Taizhou City were indica, and could be subdivided into different genotypes. The majority (86%) of weedy rice was most closely related to hybrid rice. The Taizhou weedy rice accessions were morphologically similar, but still could be delineated into indica or japonica group by some morphological traits. It is suggested that the levels of genetic and morphological diversities of weedy rice in Taizhou City are low and these weedy rice plants originated from the segregating progenies of hybrid rice that had naturally introgressed with cultivated rice.展开更多
Weedy rice （Oryza sativa f. spontanea）, the predominant type of which has a red pericarp, seriously inhibits growth and yield of direct-seeded rice in Jiangsu Province, China. In this study, we randomly selected 10 ...Weedy rice （Oryza sativa f. spontanea）, the predominant type of which has a red pericarp, seriously inhibits growth and yield of direct-seeded rice in Jiangsu Province, China. In this study, we randomly selected 10 weedy rice accessions from 10 plots in Jiangsu, and then sequenced the full lengths of their Rc genes （approximately 6.4 kb）. In addition, we collected 166 different full-length Rc genes in the Oryza genus from the literature and from GenBank. A collinearity sequence analysis showed that the 10 weedy rice accessions from Jiangsu all had the same wild-type allele of the Rc gene. Single nucleotide polymorphisms indicated that the nucleotide polymorphisms （π= 0.19） and the proportion of segregation sites （ew = 0.28） of the Rc genes in the 10 weedy rice accessions from Jiangsu were higher than those in 56 weedy rice accessions from USA （π = 0.09 and θw = 0.07）. Haplotype and phylogenetic analyses showed that the Rc genes of weedy rice accessions from Jiangsu were not revertants of the rc gene found in Asian cultivated rice （O. sativa） varieties with white pericarp. In addition, Rc gene sequences of the rice varieties Lvdao from Lianyungang, Jiangsu and Tangdao from Anhui were more similar to those of cultivated rice than to the weedy rice from Jiangsu. These findings support the continued quarantine of weedy rice and clarify the evolutionary mechanism of the red pericarp found in the weedy rice of Jiangsu.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41967054,41830322)。
文摘The analysis of wild rice cell structures,tissues,organs,and other morphological characteristics and the development of identification markers for wild rice are the basis for identifying the origins and evolution of prehistorical rice agriculture.However,contemporary wild rice strains are often subject to gene introgression from domesticated rice cultivated by humans during the evolutionary process,which may affect the accuracy of wild rice identification markers.This means that how to eliminate the effects of gene introgression from domesticated rice and other plants on the identification of origin markers,and the purification of the morphological characteristics of wild rice have become critical in research to identify the origin of rice.In this study,we compared and analysed the phytolith morphologies of three common wild rice species(Oryza rufipogon Griff.)from various habitats and one species of ectopically preserved homozygous common wild rice after six consecutive generations of self-crossing.We found that the morphology of the bulliform phytolith in the homozygous wild rice with reduced domestication gene introgression had three significant differences compared with native wild rice:(1)an overall reduction in size(body length decreased from 41.9μm in VLnativeto 38.6μm in VLhomozygous);(2)an increase in the proportion of the long-stalked phenotype,with the ratio of B/A decreasing from 1.22±0.47 in B/Anativeto 0.92±0.30 in B/Ahomozygous;and(3)a decrease in the number of fish-scale decorations,with the proportion of bulliform phytoliths with≥9 fish-scale decorations reduced from 53.4%in native wild rice to 37.2%in homozygous wild rice.Thus,this study provides a reliable reference for the identification of rice origins using rice phytolith morphology.
基金supported by the National Key Tech-nology Research and Development Program of China(2006BAD13B01)the Protective Program of Crop Germpalsm of China (NB05-070401-22-01)the Cooperative Research between China and Korea (2004-2007)
文摘The genetic similarity and genetic difference among improved japonica rice varieties from different countries （or regions and organizations） were detected. The aim is to provide genetic basis to the breeding of japonica rice varieties. The genetic similarity and cluster of 313 improved japonica varieties from 20 countries （or regions and organizations） were analyzed using the SSR marker. With 34 SSR primers which were polymorphic and uniformly distributed in rice genome, totally 198 alleles were detected among these improved varieties with the average number of alleles per pair of primers of 5.8235. RM320, RM531, RM1, RM21, and RM336 located more alleles, which were 16, 13, 12, 10, and 10 respectively. RM320, RM336, RM286, RM531, and RM21 showed higher genetic diversity indexes, which were 2.3668, 2.0041, 1.9684, 1.9508, and 1.7203, respectively. The genetic similarity for improved japonica varieties among different countries （or regions and organizations） were ranged from 0.279 to 0.918, and the mean value was 0.653. The rice varieties from countries whose latitude and geography position were all nearer were clustered together with higher genetic similarity indexes. The rice varieties from countries who had more different latitude and far geography position were clustered separately with lower genetic similarity indexes. The results indicated the genetic similarity indexes among improved japonica varieties had a close relationship with the geographical position, especially with the latitude.
文摘cies of cultivated rice in ancient China is possibly more northward than in the modern times. The earliest rice grains unearthed from the Neolithic sites existed along the lower and middle reaches of the Yangtze River. The later ones were found in Yunnan Province, South China and along the Yellow River reaches. Primitive rice cropping in the Taihu Lake region which is on the lower reach of the Yangtze River has already a 6,000-7,000 years history and the primitive tribes growing rice there are ancestors of the Yue Nationality since the beginning of the history, hence the Yue Nationality is the most important one for rice cropping in China. During the periods of Spring-Autumn and Warring States to Qin and Han Dynasties (from 722 B.C. to A.D.220 ), Yue people disseminated rice to Japan, Korea and other Southeast Asian countries by sea. In the period of over 3,000 years since the recorded history,the rice development in China has experienced changes from north to south and from south to north. As Chinese c
基金supported by the National Natural Science Foundation of China (Grant No. 30571231)
文摘Microsatellite markers and morphological characteristics were used to explore the genetic diversity and possible origin of weedy rice in Taizhou City, Jiangsu Province, China. Fifty-two weedy rice (Oryza sativa L.) accessions were compared with two wild rice, four hybrid rice and five cultivars using 22 simple sequence repeat (SSR) primer pairs. A total of 107 fragments were amplified, averaging 5.6 alleles per primer pair. The polymorphic index content (PIC) values ranged from 0.3077 to 0.7951, averaging at 0.5870. The average genetic distance of all samples ranged from 0.02 to 0.46 with an average of 0.262. The genetic distance among Taizhou weedy rice ranged from 0.03 to 0.44 with an average of 0.224. Cluster analysis showed that all the weedy rice accessions from Taizhou City were indica, and could be subdivided into different genotypes. The majority (86%) of weedy rice was most closely related to hybrid rice. The Taizhou weedy rice accessions were morphologically similar, but still could be delineated into indica or japonica group by some morphological traits. It is suggested that the levels of genetic and morphological diversities of weedy rice in Taizhou City are low and these weedy rice plants originated from the segregating progenies of hybrid rice that had naturally introgressed with cultivated rice.
基金financially supported by the National Basic Research and Development Program of China (Grant No. 2007CB109202)the China Transgenic Organism Research and Commercialization Project (Grant Nos. 2008ZX08011 and 2009ZX08012-020B)+4 种基金the Natural National Science Foundation of China (Grant No. 30800604)the Jiangsu Postdoctoral Foundation (Grant No. 0701040B)the National College Students’ Innovative Undertaking Plan of China (Grant No. 111030702)Jiangsu Science and Technology Support Project (Grant No. BE2011353)Special Fund for Agro-Scientific Research in the Public Interest of China (Grant No. 201303022)
文摘Weedy rice （Oryza sativa f. spontanea）, the predominant type of which has a red pericarp, seriously inhibits growth and yield of direct-seeded rice in Jiangsu Province, China. In this study, we randomly selected 10 weedy rice accessions from 10 plots in Jiangsu, and then sequenced the full lengths of their Rc genes （approximately 6.4 kb）. In addition, we collected 166 different full-length Rc genes in the Oryza genus from the literature and from GenBank. A collinearity sequence analysis showed that the 10 weedy rice accessions from Jiangsu all had the same wild-type allele of the Rc gene. Single nucleotide polymorphisms indicated that the nucleotide polymorphisms （π= 0.19） and the proportion of segregation sites （ew = 0.28） of the Rc genes in the 10 weedy rice accessions from Jiangsu were higher than those in 56 weedy rice accessions from USA （π = 0.09 and θw = 0.07）. Haplotype and phylogenetic analyses showed that the Rc genes of weedy rice accessions from Jiangsu were not revertants of the rc gene found in Asian cultivated rice （O. sativa） varieties with white pericarp. In addition, Rc gene sequences of the rice varieties Lvdao from Lianyungang, Jiangsu and Tangdao from Anhui were more similar to those of cultivated rice than to the weedy rice from Jiangsu. These findings support the continued quarantine of weedy rice and clarify the evolutionary mechanism of the red pericarp found in the weedy rice of Jiangsu.
