The phenomenon of degenerated spikelets is very common in cereals, and considered as a serious physiological defect and a main constraint to grain production. Understanding the physiological mechanism in which spikele...The phenomenon of degenerated spikelets is very common in cereals, and considered as a serious physiological defect and a main constraint to grain production. Understanding the physiological mechanism in which spikelet degeneration occurs would have great significance in enhancing yield potential in grain crops. Taking rice as an example, the paper reviewed the physiological mechanism underlying spikelet degeneration, with focus on the roles of phytohormones in regulating the process. There are several hypotheses for the spikelet degeneration, such as resource limitation, self-organization, and primigenic dominance. However, convincing evidences are not enough to support the assumptions. Phytohormones including auxins, cytokinins, gibberellins, abscisic acid, and ethylene are involved in regulating spikelet degeneration in cereals. The new phytohormones of brassinosteroids and polyamines have been observed to suppress spikelet degeneration in rice. The interactions among or between plant hormones may play a more important role in regulating spikelet degeneration. However, the information on such interactions is very limited. Some agronomic practices, especially proper water and nitrogen management, could reduce spikelet degeneration but the mechanism underlying remains unclear. Further research is needed to understand the cross-talk among/between phytohormones on spikelet degeneration, to reveal the physiological and molecular mechanism in which phytohormones and their interactions regulate the degeneration of spikelets, to exploit approaches to decrease spikelet degeneration and to elucidate their mechanism.展开更多
The DNAfragments about 1 600 bp were amplified using random amplified polymorphism DNA （RAPD） primer OPAl2 with the templates of mitochondrial DNA of Zhenshan 97A and Zhenshan 97B, and were sequenced. The nucleotide...The DNAfragments about 1 600 bp were amplified using random amplified polymorphism DNA （RAPD） primer OPAl2 with the templates of mitochondrial DNA of Zhenshan 97A and Zhenshan 97B, and were sequenced. The nucleotide sequences and lengths of the fragments from Zhenshan 97A and Zhenshan 97B showed no difference. The precise length of the fragment was 1 588 bp. Sequence characterized amplification region （SCAR） primers were then developed to discriminate the cytoplasmic male sterile （CMS） lines and their maintainer lines. A specific 1 588 bp fragment could be amplified with SCAR primers, CHI19F2/CHI19R2 and CHI20F3/CHI23R3, in the mitochondrial DNA of Zhenshan 97A, but not Zhenshan 97B. Furthermore, the specific fragment could be also amplified from the total DNA from green leaf tissues of Zhenshan 97A with SCAR primers, but not Zhenshan 97B. With the corresponding primers, the specific fragment could also be amplified from the total DNA of green leaves of other two CMS lines with wild abortive type cytoplasm （CMS-WA）, namely Zhenpin A and Tianfeng A, but not in their maintainer lines. Moreover, using total DNA as template, each of the four pairs of SCAR primers could also be used to amplify the 1 588 bp fragment in CMS-ID （Indonesia paddy type） line 11-32A but not in 11-32B, and the specific fragment was amplified from the DNA of both F1 and F2 seedlings of Shanyou 63. The results of detecting the genetic purity of a man-made mixture of the seeds of Zhenshan 97A using CHI20F3/CHI23R3 were completely consistent with the phenotypes. Taken together, these results indicated that the specific 1 588 bp-fragment amplified by CHI20F3/CHI23R3 was the unique amplification products of CMS mitochondrial DNA, and could be used to distinguish CMS-WA and CMS-ID lines from their corresponding maintainer lines at the seedling stage.展开更多
The mechanism of early generation stability （EGS） in rice was studied via genetic analysis. Three types of crosses were made, namely between EGS varieties, EGS and conventional rice variety, and conventional rice va...The mechanism of early generation stability （EGS） in rice was studied via genetic analysis. Three types of crosses were made, namely between EGS varieties, EGS and conventional rice variety, and conventional rice varieties. The genetic analysis was based on the stable lines in F2 population. The stable lines may appear from some combinations of EGS rice crossing with each other and EGS rice crossing with conventional varieties at different frequencies, but stable lines didn＇t appear in conventional varieties crossing with conventional varieties. Genetic analysis results indicated that the EGS phenomena should just exist in special rice materials, and the frequency of stable lines was closely related to the EGS traits of parents. The EGS traits were neither qualitative nor quantitative traits, and they were controlled by neither dominant genes nor recessive genes. The EGS traits might be inherited by F1 single plant, and the traits of F3 and F4 were corresponded to those of F2 population, i.e. F3 and F4 lines derived from non-segregating F2 showed uniform agronomic traits, and those from segregating F2.did not. The agronomic traits of EGS lines were consistent with those of F1 single plant. On the other hand, when EGS lines occurred, the segregating lines in Mendelian manner were also observed in all F2 population of the same combination. It was suggested that the reason why the stable strains occurred might be a special factor to control （open/close） gene at the beginning of cell division in zygote, resulting in closing mitosis and opening somatic reduction. The somatic reduction of zygote resulted in recombination and homozygosity forming in F1 single plant, and some lines with uniform agronomic traits were observed in some lines of F2 population.展开更多
The QTL qHUS6 for hull silicon content in rice was previously located on the short arm of rice chromosome 6. By using an F2：3 population segregating in the RM587-RM19784 region harboring qHUS6 in an isogenic backgrou...The QTL qHUS6 for hull silicon content in rice was previously located on the short arm of rice chromosome 6. By using an F2：3 population segregating in the RM587-RM19784 region harboring qHUS6 in an isogenic background, two QTLs for hull silicon content were detected, of which qHUS6-1 was located in the distal region and qHUS6.2 in the region proximal to the centromere. Three rice plants carrying small heterozygous segments in the target region were selected, of which two covered the qHUS6-1 region and the other covered the qHUS6-2 region. Three F2：3 populations were derived from the selfed seeds of the three plants, respectively. QTL mapping was performed using the two populations segregating in the qHUS6-1 region, and qHUS6-1 was delimited to a 147.0-kb region flanked by the markers RM510 and RM19417. Five groups of F3 lines with different genotypic compositions in the qHUS6-2 region were selected from the other F2-3 population. Two QTLs were separated with two-way ANOVA, of which qHUS6-2a was located in the interval defined by RM19706-RM19795 and qHUS6-2b in the interval RM314-RM19665.展开更多
基金supported by the National Natural Science Foundation of China (31471438 and 31771710)the National High-Tech R&D Program of China (863 Program, 2014AA10A605)+2 种基金the National Key Research and Development Program of China (2016YFD0300206-4)the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD)the Top Talent Supporting Program of Yangzhou University, China (2015-01)
文摘The phenomenon of degenerated spikelets is very common in cereals, and considered as a serious physiological defect and a main constraint to grain production. Understanding the physiological mechanism in which spikelet degeneration occurs would have great significance in enhancing yield potential in grain crops. Taking rice as an example, the paper reviewed the physiological mechanism underlying spikelet degeneration, with focus on the roles of phytohormones in regulating the process. There are several hypotheses for the spikelet degeneration, such as resource limitation, self-organization, and primigenic dominance. However, convincing evidences are not enough to support the assumptions. Phytohormones including auxins, cytokinins, gibberellins, abscisic acid, and ethylene are involved in regulating spikelet degeneration in cereals. The new phytohormones of brassinosteroids and polyamines have been observed to suppress spikelet degeneration in rice. The interactions among or between plant hormones may play a more important role in regulating spikelet degeneration. However, the information on such interactions is very limited. Some agronomic practices, especially proper water and nitrogen management, could reduce spikelet degeneration but the mechanism underlying remains unclear. Further research is needed to understand the cross-talk among/between phytohormones on spikelet degeneration, to reveal the physiological and molecular mechanism in which phytohormones and their interactions regulate the degeneration of spikelets, to exploit approaches to decrease spikelet degeneration and to elucidate their mechanism.
基金financially supported by the National High-Tech Research and Development Program of China(Grant No.2010AA101301)the Program of Introducing Talents of Discipline to Universities(Grant No.B08025)+1 种基金the '948' Program of Ministry of Agriculture,China(Grant No.2006-G8[4]-31-1)the Key Project of Scientific Base Qualification Platform of Ministry of Education,China(Grant No.505005)
文摘The DNAfragments about 1 600 bp were amplified using random amplified polymorphism DNA （RAPD） primer OPAl2 with the templates of mitochondrial DNA of Zhenshan 97A and Zhenshan 97B, and were sequenced. The nucleotide sequences and lengths of the fragments from Zhenshan 97A and Zhenshan 97B showed no difference. The precise length of the fragment was 1 588 bp. Sequence characterized amplification region （SCAR） primers were then developed to discriminate the cytoplasmic male sterile （CMS） lines and their maintainer lines. A specific 1 588 bp fragment could be amplified with SCAR primers, CHI19F2/CHI19R2 and CHI20F3/CHI23R3, in the mitochondrial DNA of Zhenshan 97A, but not Zhenshan 97B. Furthermore, the specific fragment could be also amplified from the total DNA from green leaf tissues of Zhenshan 97A with SCAR primers, but not Zhenshan 97B. With the corresponding primers, the specific fragment could also be amplified from the total DNA of green leaves of other two CMS lines with wild abortive type cytoplasm （CMS-WA）, namely Zhenpin A and Tianfeng A, but not in their maintainer lines. Moreover, using total DNA as template, each of the four pairs of SCAR primers could also be used to amplify the 1 588 bp fragment in CMS-ID （Indonesia paddy type） line 11-32A but not in 11-32B, and the specific fragment was amplified from the DNA of both F1 and F2 seedlings of Shanyou 63. The results of detecting the genetic purity of a man-made mixture of the seeds of Zhenshan 97A using CHI20F3/CHI23R3 were completely consistent with the phenotypes. Taken together, these results indicated that the specific 1 588 bp-fragment amplified by CHI20F3/CHI23R3 was the unique amplification products of CMS mitochondrial DNA, and could be used to distinguish CMS-WA and CMS-ID lines from their corresponding maintainer lines at the seedling stage.
基金China Natural Science Foundation(30001037) Youth Foundation of Sichuan Province,China.
文摘The mechanism of early generation stability （EGS） in rice was studied via genetic analysis. Three types of crosses were made, namely between EGS varieties, EGS and conventional rice variety, and conventional rice varieties. The genetic analysis was based on the stable lines in F2 population. The stable lines may appear from some combinations of EGS rice crossing with each other and EGS rice crossing with conventional varieties at different frequencies, but stable lines didn＇t appear in conventional varieties crossing with conventional varieties. Genetic analysis results indicated that the EGS phenomena should just exist in special rice materials, and the frequency of stable lines was closely related to the EGS traits of parents. The EGS traits were neither qualitative nor quantitative traits, and they were controlled by neither dominant genes nor recessive genes. The EGS traits might be inherited by F1 single plant, and the traits of F3 and F4 were corresponded to those of F2 population, i.e. F3 and F4 lines derived from non-segregating F2 showed uniform agronomic traits, and those from segregating F2.did not. The agronomic traits of EGS lines were consistent with those of F1 single plant. On the other hand, when EGS lines occurred, the segregating lines in Mendelian manner were also observed in all F2 population of the same combination. It was suggested that the reason why the stable strains occurred might be a special factor to control （open/close） gene at the beginning of cell division in zygote, resulting in closing mitosis and opening somatic reduction. The somatic reduction of zygote resulted in recombination and homozygosity forming in F1 single plant, and some lines with uniform agronomic traits were observed in some lines of F2 population.
基金supported by the National Natural Science Foundation of China(GrantNo.30571062)National Hi-Tech Research and Development Program of China(Grant No.2006AA10Z1E8)the Program of Super Rice from Chinese Agricultural Ministry(Grant No.200906)
文摘The QTL qHUS6 for hull silicon content in rice was previously located on the short arm of rice chromosome 6. By using an F2：3 population segregating in the RM587-RM19784 region harboring qHUS6 in an isogenic background, two QTLs for hull silicon content were detected, of which qHUS6-1 was located in the distal region and qHUS6.2 in the region proximal to the centromere. Three rice plants carrying small heterozygous segments in the target region were selected, of which two covered the qHUS6-1 region and the other covered the qHUS6-2 region. Three F2：3 populations were derived from the selfed seeds of the three plants, respectively. QTL mapping was performed using the two populations segregating in the qHUS6-1 region, and qHUS6-1 was delimited to a 147.0-kb region flanked by the markers RM510 and RM19417. Five groups of F3 lines with different genotypic compositions in the qHUS6-2 region were selected from the other F2-3 population. Two QTLs were separated with two-way ANOVA, of which qHUS6-2a was located in the interval defined by RM19706-RM19795 and qHUS6-2b in the interval RM314-RM19665.
