两系杂交水稻（Hybrid rice in two lines）

两系杂交水稻（Hybrid rice in two lines） 两系杂交水稻(Hybrid rice in two lines) Hybrid rice of two systems Date: July 24, 2001 source: ministry of science and technology Chinese rice, the oldest. The dwarf breeding of the 1960s increased the yield of rice in our country by 30%, and the successful three-series hybrid rice in the 1970s increased by 20% compared with the dwarf rice yield. This is two major leaps forward in the rice technological revolution in China. But since the 1980s, the production of rice in our country has been like a bamboo shoot that has stopped growing. It has always been in a stable situation, and the yield per mu is hovering around 450 kilograms. Not expand the land resources, and the population of our country one day also did not stop growing, how to guarantee to rice is the staple food in our country 60% of the population have a meal, in the 90 s scientists have invented a new method to improve the quality of the rice yield, and that is the two-line hybrid rice. The hybrid rice was bred by the light - temperature - sensitive sterile line rice. Light temperature sensitive sterile line rice is very magical. His fertility is the target of a combination of light and temperature. Specifically: the rice in the summer, long sunshine, high temperature, characterized by male sterility, and his family at this time all normal varieties, production of hybrid seeds, the seed is the seed of two high-yielding hybrid rice. This type of light temperature sensitive rice is produced in autumn, short sunshine, low temperature and normal rice, self-propagating itself, which is self-inoculation. Because rice is a flower pollination plant that belongs to male and female flowers. This hybrid rice is called a hybrid rice because it has sterile lines (maternal) and restorer (paternal) and does not need to maintain a system (intermediate). LiangXiDao biggest advantage, is between male parent, female parent is free love, until the phase, and the oneself the most desirable that a three-line rice it must go through matchmaking (keep) is the matchmaker, parents advocate to combine, regardless of whether the two varieties, fine match, so free love married LiangXiDao than arranged marriage of three-line rice quality is better, better quality and higher yield. The national 863 programme has been used as a major way to improve rice yield, improve quality and enhance resistance to disease in our country. The breeders produced 27 high yield, excellent quality, strong resistance to diseases and pests were the new hybrid rice combination, has grown in the country, total area of more than 60 million mu, output by more than 20%, higher than conventional rice accumulated more than 40 kilograms of rice yield. By the 1830s, China's population will reach 1.6 billion, ensuring that the future supply of grain will be balanced, and only by increasing the output per unit area. Scientists are using the two-tie method to cultivate super-hybrid rice, which will yield more than 20% more than the existing hybrid rice. The two-line hybrid rice in the 21st century will have more abundant nutrition, and rice contains vitamins, iron and other substances that are beneficial to human health. The rice quality of the hybrid rice is excellent, the rice is delicious and the nutritive value is higher. Genetically engineered hybrid rice, both disease-resistant and insect-resistant, and resistant to the disease, farmers can reap the harvest without spraying pesticides and fertilizing them. Such rice is the real green food. The big increase in hybrid rice yields will answer the question of "who will support the Chinese in the future" by Mr Brown. The Chinese will not only feed themselves, but will also have more high-quality rice exports to feed the world's many more people. 1.1. Principle of AFLP molecular marker technique AFLP technology is a selective amplification restricted segment based on PCR response. Because the genome DNA of different species is different, the genomic DNA is cut by restriction enzyme, which produces the restrictive segment of molecular weight. Use specific double link head connected to the enzyme DNA fragments as template amplification reaction, with primer containing the selective bases of template DNA amplification, the types, number of selective bases and sequence determines the particularity of the fragments amplified, only those restriction sites and selectivity of primers flanking the nucleotides bases that match the restriction fragment can be amplified. The amplified products were separated by radioisotope markers and polyacrylamide gel electrophoresis, and then the polymorphism [5] was tested according to the presence of DNA fingerprints on the gel. Vos et al. (1995) have verified the reaction principle of AFLP, and the number of enzyme cut fragments detected by the results is consistent with the predicted number of enzyme cutting segments, which fully proves the reliability of the technical principle of AFLP. In the analysis of AFLP, two kinds of restriction enzymes were used to enzyme the genomic DNA in the appropriate buffer system, a low-frequency shear enzyme, and the identification site was a six-base rare cutter. Another is high-frequency shearing enzyme, the identification site is a four-base of frequent cutter. Double enzyme produced by general is less than 500 bp DNA fragment length, can be preferred in markers reaction amplification, amplification products can be well separated, so the more commonly used a rare point of tangency restriction enzymes and the tangent point more restriction enzymes to match the use of double enzyme. The two enzymes currently used are the Mse I and the EcoR I of the four identification sites. AFLP connectors and primers are both synthetic double-stranded nucleotide sequences. The joint (Artificial adapter) is generally 14 ~ 18 base pairs, consisting of a Core sequence and an enzymatic sequence. Commonly used for EcoR I and Mse I joints, the base sequence of the joint and adjacent enzyme cutting segments is the binding site of primers. Markers primers consists of three parts: the 5 'end and artificial joint core of complementary sequences (core sequence, core), restriction enzyme specific sequences (enzyme - specific sequence, ENZ) and 3' end at the end of the selective bases of viscous (selective extension, EXT). 1.2. AFLP molecular marker technology process Figure 1 Markers and molecular marker technology includes three steps: (?) DNA. This is the enzyme cutting of DNA and the artificial oligonucleotide adapter (oligonucleotide adapter). In order to make the slices of the enzyme cut evenly and evenly, the two enzymes are usually cut and the low-frequency incisions and the high frequency incisions are respectively produced in the genome. (?) selective amplification enzyme fragment. The AFLP primer includes CORE sequences (CORE), restriction enzyme recognition sequence (ENZ) and 3 'end selective base 3. In general, the preamplification of primers without or with a selective base is used, and then the primers with two or three selective bases are then amplified. The primer may be radioactive or fluorescent. (?) markers mark of statistics. The AFLP products detect the polymorphism of the sample by polypropylamide modified gel electrophoresis (SDS - PAGE), and can be sensitive to different DNA fragments with only one base difference. [6] (figure 1) 1.3. Characteristics of AFLP molecular markers (1) low DNA requirements and high detection efficiency can theoretically produce an infinite number of AFLP markers. A sample of 0.5mg of DNA can do 4,000 reactions. Because AFLP analysis can be applied to various types of restriction enzymes and different number of selective bases, in theory AFLP can generate an infinite number of markers and can cover the entire genome. (2) high polymorphism. AFLP analysis can adjust the number of restriction enzymes and selective bases by changing the variety and the number of selective bases, and have a strong polymorphic resolution ability. Each reaction products can be detected by the modified polyacrylamide gel electrophoresis of tag number is 50 ~ 100, were very similar in the genetic relationship of material between polymorphism, is considered to be one of the most abundant polymorphism in fingerprint technology technique. Becker et al. (1995) carried out AFLP analysis of barley with poor polymorphism, and identified 118 locus of [7] with 16 primers. (3) good reliability and high repeatability. AFLP analysis USES specific primer amplification, annealing temperature, false positive and reliability. The AFLP marker is adhered to Mendel's law in the inheritance and separation of offspring. The AFLP marker site in the population follows the Hardy - Weinberg balance. (4) it is not sensitive to the change of the concentration of DNA template. The AFLP reaction is not high in the template concentration, and the results can be basically consistent within 1000 times of the concentration difference. However, the reaction has strict quality requirements for template DNA, and the quality of DNA affects the smooth operation of enzyme cutting and connection amplification. The application of AFLP molecular marker technology is used to edit this section to the directory Markers as a relatively new molecular markers, for nearly a decade, markers technology obtained great progress, and shows good prospects for development, has been widely applied in many fields of life science, such as zoology, botany, medicine, etc. 2.1. Applications in zoology research 2.1.1. Animal genetics (in the case of aquatic animals) AFLP is widely used in the genetic diversity of aquatic animals, systematic and chemical studies, with its large number, random distribution, stable heredity and rich polymorphism. Seki et al. (1999) analyzed the genetic diversity of three xiangfish populations with fluorescence - AFLP technique, and the results showed that the AFLP marker provided reliable information for the genetic variation and diversity assessment of fish. Markers such as Liu (1998) studied markers in spots e ? ? ?, albacore e ? ? ? and their F1, F2, and the application of backcross generations, results show the markers mark rich polymorphism loci, Mendelian inheritance patterns and good stability Miller et al. (2000) used AFLP and mitochondrial sequence information to study the genetic differentiation and kinship of two endangered amber conch. [8] The water industry is an economic growth point, and the dependence on biotechnology is becoming more and more. The AFLP technique, as a genetic marker for generations, has been successfully applied to aquaculture and screening the desired species at the chromosomal level. Montano - Perez et al. (2006) summarized [9] in detail in a recent review. In addition, artificial female nuclear development and artificial induction of male nuclear development can be used for gender control and rapid establishment of a family, so that the related work in various economic aquatic animals has been widely spread. The AFLP technology has the advantages of other similar technologies in the construction of the genetic map of aquatic animals. Since the launch of the American aquatic animal genome project in 1996, more and more aquatic animal heritage maps have been established. In 1998, Kocher and others published the first genetic linkage map of the Orechromis niloticus. Young, such as use of androgenesis double haploid steelhead to include a variety of tag markers, built a preliminary linkage map, Nichols, etc on the original added more tags (including more than 700 markers mark), making it the detailed maps. In 2000, Naruse made use of 633 markers to construct a more detailed map of the silver carp chain, including 488 AFLP markers. In 2002 Wilson published a map of the AFLP. Guo and others have constructed an initial map of the Pacific oyster. [8] 2.1.2. Animal systems (in the case of insects) In classification, AFLP technology can be used to identify and plant the lower order. Corsini analyzed (1999) using markers technologies such as Chile, different areas of the Mediterranean fruit fly (Ceratitis capitata) genetic diversity, and cloned the three rich in ats markup fragment, can be used as identification of Mediterranean fruit fly genera (Ceratitis) other species and genus (Drosophila) between insect molecular probe [10]; Jin-wei zhang (2004) by using molecular markers techniques such as six silkworm varieties (b. mori), DNA fingerprinting amplified the article 54 polymorphic bands, can make a clear distinction between 6 silkworm varieties, and can be taken as the basis for six silkworm varieties identification [11]. The genetic variation of animals is difficult to find in morphology, and it is easy to find this difference at the molecular level and can be studied in detail. Htiseyin etc. (2002) to Turkey Antalya province different area, different host eight whiteflies (Bemisia tabaci) population markers analysis, found that eight species genetic variation coefficient change in the range of 42% 81%, the clustering results show that the smoke of different populations of gene mutation may be caused by adaptation for the host, [12]. Zhang lp (2004), such as type B were studied using markers technology whiteflies (Bemisia tabaci) resistance thiamethoxam oxazine (thiamethoxam) strain at the level of DNA molecular genetic differentiation and analysis results showed that the resistant strains in DNA molecular level there is a clear differentiation [13]. As the basis for determining the relationship between insect systems, the relationship of the relationship is obviously deficient. It has become a hot topic in recent years to explore its evolutionary relationship from molecular level [14]. LuCheng (2001) use of markers such as technology and statistical means of 10 kinds of wild silkworm and representative China 33 kinds of silkworm and five as a group of tussah contrast analysis, found that the genetic distance between different parts of the wild silkworm silkworm varieties (0.10004-0.10004) and the genetic distance between similar (0.10004 0.1406), and with wild mulberry silkworm genetic distance (0.13554 0.1532) between much smaller than with tussah silkworm (0.17614 0.1865), and wild mulberry and silkworm (0.17764 0.1839) the genetic distance between that originated in Chinese wild mulberry silkworm [15]. In addition, in the meat industry, the genetic tagging technology provides reliable guarantee for the quality information of meat products. Using markers technology can filter out 6 kinds of tag, and translated into single nucleotide polymorphism markers used for high yield genotype, so as to accurately identify the Japanese Black cattle (Japanese Black) and F1 hybrids (Japanese Black x Holstein), the reliability of 88.2%. [16] 2.1.3. Research on gender identification and reproductive behavior AFLP techniques have successfully screened the labeling of individual gender chains in many species. Behura (2000), such as a poison in Asia only rice is offered to the mosquito in the creature type, 2, 5 l and not in the biological markers in type 4 tags Gm2 genes, based on the sequence of the markers tags, designed the SCAR primers specific amplification (sequence), through multiple PCR test can effectively identify five different biological type. In the creature type 1 x 4 and 2 x 4 hybrids of genetic markers of the research shows that: all Fl females can mark, PCR amplification of the markers and male offspring in the tag appears only in the female parent Gm2 is non-toxic biological type of individuals. The specific amplification and genetic methods of AFLP markers in non-toxic biological models indicate that Gm2 gene is linked to the sex chain of the virus. In the study of reproductive behavior, Questiau et al. (2000) used AFLP technique to find a very common marital diplomatic distribution in the population of the blue throat (Luscinia svecica ramnetum). Therefore, the AFLP marker can be used in the study of many classification unit mating systems without microsatellite analysis primers. [17] 2.2. Applications in botany studies 2.2.1. Identification of germplasm resources Genetic background and genetic relationship of crop germplasm resources are of great importance in crop breeding. Jin-you du (2006), such as using markers and molecular marker technology of 55 maize (Zea mays l.) germplasm materials was studied, the results showed that 20 of markers primers detect visible with article 656, article 487 polymorphism with. The average primer combination can detect 24.4 polymorphisms. The 55 corn materials were assembled into 6 groups, which were basically the same as the source material. Many materials in the Pioneer series of America were related to the rime population. The results also showed that AFLP was beneficial to the analysis of the genetic diversity of maize. Wheat germplasm resources, AFL is widely used in genetic diversity research, wheat germplasm fingerprint identification and genetic materials, wheat genetic linkage map construction of the building, aim gene molecular orientation, marker-assisted selection and gene expression regulation and cloning research [19]. In tea tree research, Wachira et al. (2001) adopted both RAPD and AFLP methods. Coming from all over the world, India, Sri Lanka, China and Taiwan province of China, Japan, Vietnam, Kenya, etc.) of 40 varieties of tea plant genetic diversity research, clustering analysis can be divided into three main groups, statistical analysis showed that the variation between individuals within a population, the largest degree of variation was 72%, and the calculation results show that the genetic distance of tea plant varieties from different countries, there are abundant genetic variation in populations in [20]. Wang (2006), such as using markers technology from five countries such as America's 21 kinds of ornamental plants of the genus ginkgo were analyzed, and their genetic link, found eight important germplasm varieties, and clustering results show that the varieties from the same regions do not necessarily belong to the same class [21]. 2.2.3. Crop breeding Markers application in plant breeding is widespread, not only on wheat, rice, corn, cotton and soybean on main crops such as the application, and in the vegetables, tomato, potato, etc.) and the plant base figure groups are widely used in model plant arabidopsis thaliana. Vantoall (1996) guidance of markers technology in soybean backcross breeding parents compare soybean and backcross 1 or 2 C0 and backcross generation C1 degree of heterogeneity, the average markers have 10 mark polymorphic primers, 10 markers primers can detect more than 100 loci of homozygous or heterogeneous degree. Reddy (1996) using markers technology such as filtering and cotton long wool and high yield characters and molecular markers, they will long pile of sea island cotton with high yield of upland cotton TM - 1 3.79, distant hybridization results show that the use of 64 pairs of primers. Each pair of primers were detected 3-10 markers, in hybrids F2 populations found 300 markers associated with long wool and high yield traits. Markers tag can also be converted into a SCAR (Sequence characterized amplified region) tag, it will be more conducive to the application of molecular markers in the breeding selection. [22] On crop pest and disease resistance varieties screening, Wang and Roberts (2006) reviewed the use of markers in a recent review and CAPS (Cleaved amplified polymorphic sequence) tag on the research of the resistance of cotton root knot nematodes, mentioned by using markers screened 4 with resistance genes rkn1 chain, and can be fixed in the F2 generation. [23] 2.3. Medical applications AFLP technology has been widely used in medicine and has shown its unique superiority. In the aspect of tumor research, Fukuda et al. (1999) used cDNA - AFLP method to clone four different expression genes related to the metastasis of osteosarcoma in rats. Majima et al. (2000) applied the same method to clone a new gene, Niban, associated with renal cancer. It is an ideal method to study the pathogenesis of tumor by suggesting that the AFLP method is suitable for screening and detection of tumor related genes. [24] Genetic disease research, YuDongYi (2004), such as using the PCR - markers technology to Down's syndrome (Down syndrome, DS) study, select four highly polymorphism on chromosome 21 STR loci on 12 cases of fetal prenatal diagnosis. Results two patients with down syndrome were detected. The results were consistent with the results of cytogenetic tests, and no false negative or false positive cases occurred. Description of four STR loci are highly polymorphic, application of PCR - markers technology to detect each point genotype, prenatal diagnosis by the typical and translocation down's syndrome fetuses type, high accuracy, easy operation, fast, has a great clinical application value. [25] AFLP technology is also a good tool for epidemiological research and diagnosis. Rob (2000) from the healthy people, the disease such as different parts of the people and some animals, such as the excrement and urine, blood, pus, urine and ascites) separation of vancomycin resistant Enterococcus (vancomycin - resistant Enterococcus faecium, VREF) strain markers analysis results show that the vancomycin resistant Enterococcus have host specificity, strains isolated from healthy people and diseases in the crowd obviously belong to different markers cluster, and from the healthy people and strains were isolated from pigs form a cluster, at the same time in the animal breeder poultry and cattle and butcher's feces VREF endemic and rare in the crowd, such as Rob VREF think it fully demonstrated the crowd are mainly originated from the high sugar peptide VREF of parasitic resistance in pigs, and cattle and cattle VREF can also spread to the crowd briefly. [17] The conclusion is editing this segment back to the directory Since its invention, the AFLP technology has become an important tool and means for the study of molecular genetics in various fields of life science, as a good reproducibility and high resolution DNA marker. In recent years, with the continuous improvement and improvement of the technology, this method is more convenient and easy to operate, and the application scope is also expanding. The technology also has some shortcomings, such as the high requirement of the quality of the DNA of the samples which is easy to lead to deviation, high equipment cost, but with microsatellites markers technology, comprehensive analysis of sequence information can be used as genetic variation analysis of the main tools. Therefore, the researchers should comprehensively consider the advantages and limitations of AFLP technology, and select according to specific research content and needs. National department heads Beijing, March 16 (xinhua) according to the constitution, the state council premier li keqiang to nominate the ministries, commissions, governor of the people's bank of China, the auditor-general and the secretary-general candidate: campaign as the secretary-general of the state council; Wang yi is a candidate for foreign minister. Chang wanquan is the minister of defense department; Xu shaoshi is the director of the national development and reform commission; Yuan guiren was a candidate for the ministry of education. Wan gang is the minister of science and technology department; Miao wei is the minister for industry and information technology; Wang zhengwei is the director of national ethnic affairs committee; Guo shengkun is the minister of the ministry of public security; Geng huichang is the national security secretary; Mr. Huang is a candidate for the ministry of supervision. 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