Hybridization; ; Cross; Cross) definition: base pairing of two single-stranded DNA or RNA. Classical and commonly used experimental methods in geneti
Hybridization; ; Cross; Cross) definition: base pairing of two single-stranded DNA or RNA. Classical and commonly used experimental methods in genetics. A method for obtaining individuals whose parents are genetically recombined by mating between individuals with different genotypes. Generally speaking, the process of achieving this goal through the mutual fusion of germ cells is called hybridization; The process of achieving this result by somatic cell fusion is called somatic hybridization.
Chinese name: hybrid mbth: hybrid pinyin: zá jiāo Definition: explain in detail the hybridization between one plant and another, the principle of hybridization, practical use, the mystery of hybridization, related terms, male sterile line, maintainer line, restorer line, three-line hybrid rice, two-line hybrid rice and super hybrid rice, and explain in detail 1. Song read the ninth of Su Shu Party's "Ruzhou Beishan Miscellaneous Poems": "Don't cross the door, everything will be done at once." 2. promiscuity between men and women The most primitive form of human marriage. Guo Moruo's Study of Ancient Society, Chapter 3, Chapter 2, Section 1: "The ancestor of five emperors and three kings was born out of a sense of heaven, and it is a natural phenomenon to know that he has a mother but no father. That dark shot is the shadow of the hybrid era or the group marriage era. " See "abortion". Biology refers to the mating of animals and plants of different species, genera or varieties. The offspring produced by hybridization are called hybrids. The mating of individuals between different species or geographically distant subspecies is called distant hybridization, and the individuals obtained are called distant hybrids. On the contrary, the hybridization between closely related individuals is called inbreeding, or inbreeding, including sibling hybridization and half-sibling hybridization (see inbreeding). Inbreeding can be used to establish pure lines. The mating between the same individual or cloned individuals is called selfing. All mating except self-crossing belongs to outcrossing, regardless of genotypic differences between parents. Hybridization principle Hybridization is produced by crossing different rice seeds with each other. Rice is a self-pollinated crop, which is not conducive to the preparation of hybrid seeds. In order to cross two different rice varieties, the stamens of one variety should be artificially emasculated or killed, and then the stamen pollen of the other variety should be given to the emasculated variety, so that there will be no false hybridization in which the emasculated variety pollinates itself. However, if tens of thousands of rice flowers are emasculated and pollinated manually, the workload is huge, and it is actually impossible to solve a large number of seeds used in production. So a kind of rice was bred as the female parent, which has a special personality, with thin stamens and withered anthers. You can't fertilize and sow with your own pollen. In order not to cut off the offspring of the mother, we should find two objects for it. The characteristics of these two objects are different: the first object looks very much like the female parent, but has sound pollen and developed stigma. When its pollen was given to its female parents, it gave birth to a daughter. She looks exactly like her mother, and she is also a female parent. The stamens are thin and degenerate, the anthers are withered and deformed, and there is no fertility. The other object is completely different from the female parent in appearance, generally taller than the female parent, and also has sound pollen and developed stigma. After its pollen was given to the female parent, it gave birth to a son, stronger than both parents. This is the required hybridization. According to their different characteristics, a female parent and its two objects have three names: the female parent is called sterile line, the two objects are called maintainer line, and the other is called restorer line, abbreviated as "three lines". With the "three-line" system, we can know how to prepare for hybridization in production: a breeding farm and a seed-making field should be planted in production, and a sterile line and a maintainer line should be planted in the breeding farm. When both flowers bloom, the pollen of the maintainer line is transferred to the sterile line by wind, and the sterile line will get normal pollen fruiting, and the offspring will still be sterile, thus achieving the purpose of breeding the sterile line. A part of the propagated sterile line seeds can be reserved for the next year to continue reproduction, and the other part can be used for seed production together with the restorer line. When both the sterile line and the restorer line in the seed-making field bloom, the pollen of the restorer line is transferred to the sterile line, and the offspring produced by the sterile line is the hybrid rice seeds planted in the field. Because the male and female stamens of the maintainer and restorer lines are normal and self-pollinated, the seeds they produce are still the descendants of the maintainer and restorer lines. Investigation on the Practical Application of Hybrid Rice The patent documents of hybrid rice in the United States mainly come from Texas, California, Chinese mainland and other regions. For example, RingAround Products Company, RiceTec Company, NorCal Wild Rice Company, KenFoster, BarryL. Tillman Eugenios. Sarreal, etc. Submitted relevant patent applications. China Seed Company also submitted several applications. In China National Intellectual Property Administration, China, in addition to Nanjing Liangyoupeijiu Seed Industry Co., Ltd., other units and individuals have published more than 200 patent documents of hybrid rice invention technology around the world. Among them, there are few foreign applications, mainly from the United States and Japan. For example, the document CN9 1 102598.7 of American Peripheral Products Company relates to a method for producing hybrid rice by using perennial male sterile rice plants. The document CN88 1092 18.5 of Japanese company relates to a method for cultivating hybrid rice seeds. It includes making male sterile female parent rice resistant to herbicide, crossing female parent rice with male parent rice to produce hybrid rice seeds, and treating parents with herbicide resistant to female parent rice to kill only male parent rice, thus selecting hybrid rice seeds. The document CN0 18 16569 jointly applied by two Japanese companies relates to a detection method for restoring BT cytoplasmic male sterility gene in hybrid rice breeding. It can use several PCR markers near Rf- 1 site and the linkage between Rf- 1 site to detect Rf- 1 gene. China submitted the most patent applications for hybrid rice. Among them, there are about 56 individual applications, and some patented technologies owned by natural persons have broad application prospects and have been promoted by private high-tech enterprises. The application of research institutions is about 135. The main institutions applying for scientific research are Rice Research Institute of Guangdong Academy of Agricultural Sciences, Hunan Plant Protection Research Center, Hunan Hybrid Rice Research Center, South China Agricultural University, Nanjing Agricultural University, Jiangsu Academy of Agricultural Sciences, and Crop Research Institute of Sichuan Academy of Agricultural Sciences. There are few applications from enterprises, among which Dabeinong and other companies have the strongest patent strength. Dabeinong Group, as the holding company of Nanjing Liangyoupeijiu Seed Industry Co., Ltd., is one of the largest agricultural companies in China. Among the national agricultural enterprises, Dabeinong Group has the strongest scientific research strength. In terms of market layout, it is the only local enterprise in China that may compete with foreign agricultural enterprise groups such as Monsanto. The hope of agriculture in China depends on private scientific and technological enterprise groups such as Dabeinong. In Situ Hybridization (ISH) In Situ Hybridization, ISH is a molecular biological method which uses labeled nucleic acid probes, non-radioactive detection systems or autoradiography systems to qualitatively, localize and relatively quantitatively study nucleic acids in tissue sections, cell smears and chromosome sections, and has the advantages of sensitivity, specificity and intuition. It has gradually become one of the commonly used techniques in molecular biology and molecular pathology, and is widely used in tumor biology, hematology, genetics, microbiology, cell and molecular biology, neuroendocrinology, immunology and other fields, as well as treatment evaluation and prognosis judgment. In-situ molecular hybridization of colonies: refers to printing transformed or infected colonies on a filter membrane, cracking with alkali, washing and drying after neutralization, and then using radioactive DNA or mRNA of the target gene as a probe for hybridization autoradiography. Any colony with black spots should be selected. Scientists have long known that hybrid plants, such as hybrid corn, are more robust, yield higher and have bigger seeds than their parents. Polyploid plants have a similar phenomenon, and more than 70% of flowering plants are natural polyploids. However, scientists have never figured out the molecular mechanism. Chinese and American scientists have found that hybrid plants grow bigger and better than their parents because their genes responsible for photosynthesis and starch metabolism are more active during the day. This discovery will have a great impact on increasing the output of fuel crops and food crops. In the latest research, researchers from the University of Texas and China Agricultural University found that the expression of genes related to photosynthesis and starch metabolism in hybrid plants and polyploid plants increased, and the expression in daytime was several times higher than that of their parents. Hybrid plants and polyploid plants show more photosynthesis, chlorophyll and starch accumulation, all of which lead to taller plants. In further research, the researchers found a direct connection between physiological clock regulators and growth potential in hybrid plants and polyploid plants. Physiological clocks control the growth and metabolism of plants and animals. The researchers found that during the day, some regulatory factors in hybrid plants and polyploid plants-transcription inhibitors were more inhibited, leading to increased photosynthesis and starch accumulation. The researchers said that with this discovery, genome and biotechnology tools can be developed to discover and cultivate better hybrid and polyploid plants. Related terms Male sterile line is a kind of female rice with male degeneration (mainly pollen degeneration) but normal pistil. Because pollen can't live, it can't pollinate itself and bear fruit. Only exotic pollen can fertilize and bear fruit. Therefore, with this mother rice as a genetic tool, a large number of hybrid seeds can be produced by artificial pollination. The maintainer line is a normal rice variety, and its special function is that after its pollen is given to the sterile line, the offspring produced are still male sterile. Therefore, with the help of maintainer lines, sterile lines can be propagated from generation to generation. Restorer lines are normal rice varieties. Its special function is that the hybrid male produced by its pollen returns to normal and can be self-bred. If hybrids have advantages, they can be used for production. Three-line hybrid rice refers to the mating breeding of male sterile line, maintainer line and restorer line. Sterile lines provide the possibility for mass production of hybrid seeds. Breeding sterile lines with maintainer lines and pollinating sterile lines with restorer lines to produce hybrid rice with male restorer advantages. Two-line hybrid rice is a photo-thermo-sensitive sterile rice, which is closely related to sunshine length and temperature, and shows male sterility under long-term high temperature conditions. Under the condition of short-day average temperature, male fertility recovered. Hybrid rice bred by photo-thermo-sensitive male sterile line can be used with restorer line for seed production in long sunshine in summer, and can reproduce itself in autumn or spring in Hainan, so it is no longer necessary to use maintainer line to propagate male sterile line, so the hybrid rice prepared by photo-thermo-sensitive male sterile line is called two-line hybrid rice. Super-high-yield breeding of super hybrid rice is a key project of many countries and research institutions in recent 20 years. Japan took the lead in developing super-high-yield rice breeding in 198 1, and plans to increase rice yield by 50% in 15. 1989, the international rice research institute launched the "super rice" breeding plan, which required to cultivate super rice with a yield of 20%-25% higher than the highest variety at that time in 2000. But their plan has not been realized so far. The Ministry of Agriculture of China launched the China Super Rice Breeding Plan in 1996, in which the first-season yield of hybrid rice was 700 kg per mu in the first phase (1996-2000) and 800 kg per mu in the second phase (200 1-2005).