brief introduction
Two rice varieties with certain genetic differences and complementary excellent characters are selected to cross to produce a hybrid with heterosis, that is, hybrid rice.
Heterosis is a common phenomenon in biology, and using heterosis to improve crop yield and quality is one of the main achievements of modern agricultural science.
Ethnicity
Yuan Longping1971February was transferred to Hunan Academy of Agricultural Sciences to specialize in hybrid rice research. In order to strengthen and coordinate the scientific research of hybrid rice, Hunan Hybrid Rice Research Center, a national specialized research institution of hybrid rice, was established in June, 1984, and then the National Hybrid Rice Engineering and Technology Research Center was established, with Yuan Longping as its director. 1995 was elected as an academician of China Academy of Engineering.
From 65438 to 0960, Yuan Longping learned from some periodicals that hybrid sorghum, hybrid corn and seedless watermelon have been widely used in domestic and international production. This made Yuan Longping realize that the laws of gene separation, free combination and chain exchange put forward by geneticists Mendel, Morgan and their followers are of great significance to crop breeding. Therefore, Yuan Longping jumped out of the circle of asexual hybridization theory and started the experiment of sexual hybridization of rice.
1in July, 960, he found a unique rice plant in the experimental field of early rice conventional varieties. The next spring, he sowed the seeds of this mutant into the experimental field, and the results proved that this rice that stood out last year was an out-and-out "natural hybrid rice". He believes that since "natural hybrid rice" exists objectively in nature, as long as we can explore its laws and mysteries, we will certainly cultivate artificial hybrid rice according to our requirements, so as to make use of its hybrid advantages and increase rice yield. In this way, Yuan Longping broke through the traditional idea that rice is a self-pollinating plant without heterosis in practice and reasoning. Therefore, Yuan Longping immediately turned his energy to the new subject of cultivating artificial hybrid rice.
During the rice flowering period from 1964 to 1965, he and his assistants stood in the scorching sun every day, stepped on the soil and bowed their heads, and finally found six natural male sterile plants in the rice field. After two years of observation and experiment, he has a rich understanding of rice male sterile materials. Based on the accumulated scientific data, he wrote a paper, Rice Male Sterility, which was published in Science Bulletin. This is the first paper on rice male sterility in China, which not only describes the characteristics of rice male sterile plants in detail, but also divides the materials found at that time into three types: no pollen, pollen abortion and partial male sterility. Since 1964 discovered "natural male sterile plants", Yuan Longping and his assistants spent six years crossing more than 3,000 varieties with 1000, but still failed to cultivate sterile lines with sterile plant rate and sterility degree reaching 100%. Yuan Longping summed up the experience and lessons in the past six years, and according to the infertility observed by himself, he realized that it was necessary to jump out of the small circle of cultivated rice and re-select parent materials, and put forward a new idea of "crossing distant wild rice with cultivated rice". Under the guidance of this idea, Yuan Longping led his assistant Li Bihu to find the male sterile plant 1970+065438+ in the common wild rice community in Hainan Island on June 23rd, and tested it with Fangao and Jingan 66, and found that it has the ability to keep the wild sterile plant, which opened a breakthrough for cultivating the rice sterile line and the subsequent "three lines".
Should we seal up the precious data of "wild defeat" and study it behind closed doors, or mobilize more scientific and technological personnel to tackle the problem together? On this important issue of principle, Yuan Longping unequivocally and unreservedly informed the national breeding experts and technicians of his latest discovery in time, and generously distributed the "wild defeat" discovered after going through hardships to the relevant units for research, and cooperated with the "third-line" support.
From 65438 to 0972, the Ministry of Agriculture listed hybrid rice as a national key scientific research project, forming a national collaborative research network. 1973 on the basis of breaking through the "sterile line" and "maintainer line", the majority of scientific and technical personnel selected more than 1000 varieties for cross test screening, and found more than 1000 varieties with restoring ability. Zhang Xiancheng, Yuan Longping and others took the lead in discovering a number of restorer lines represented by IR24, which have strong advantages and large amount of pollen, and the restoration degree is over 90%.
1973 10 Yuan Longping published a paper entitled "Progress in Breeding Three Lines by Wild Abortion", which officially declared the success of "Three Lines" matching of indica hybrid rice in China. This is a major breakthrough in rice breeding in China. Then, he and his colleagues overcame the "heterosis obstacle" and "seed production obstacle" successively, paving the way for the utilization of rice heterosis.
In the late 1990s, American scholar Brown threw out the "China threat theory" and wrote that the population of China would reach 654.38+06 billion in the 1930s. Who will feed China and save the global food shortage and turbulent crisis caused by it? At this time, Yuan Longping announced to the world: "China can completely solve its own food problem, and China can also help people all over the world solve the food problem." . In fact, Yuan Longping has this concern. As early as 1986, in his paper "Breeding Strategy of Hybrid Rice", he put forward that the breeding method of hybrid rice can be divided into three stages: three-line method, two-line method and one-line method, that is, the breeding procedure develops from complex to simple, and the efficiency is getting higher and higher; From the level of heterosis utilization, it can be divided into three stages: interspecific heterosis utilization, interspecific heterosis utilization and distant heterosis utilization, that is, heterosis utilization is developing in a stronger and stronger direction. According to this idea, every time hybrid rice enters a new stage, it is a new breakthrough, which will promote rice production in by going up one flight of stairs. 1In August, 1995, Yuan Longping solemnly announced that after nine years, the research of two-line hybrid rice in China had made a breakthrough, which could be widely popularized in production. As envisaged in Yuan Longping's breeding strategy, the two-line hybrid rice has indeed shown a better yield-increasing effect, generally increasing the yield by 750- 1500 kg per hectare compared with the three-line hybrid rice in the same period, and the rice quality has been greatly improved. Up to now, in the production demonstration, more than 80,000 mu of two-line hybrid rice/kloc-0 has been planted nationwide. At present, the national "863" plan has taken Pei 'ai series combination as the pioneer combination of two-line hybrid rice, and has increased its promotion throughout the country.
1In August 1998, Yuan Longping launched an attack on a new commanding height. He put forward the research topic of cultivating super hybrid rice to Premier Zhu. Premier Zhu was very happy after hearing the news and immediately allocated100000 yuan to support it. Yuan Longping was greatly encouraged. At Sanya Farm Base in Hainan, Yuan Longping led a team of cooperative scientific research units from more than ten provinces and regions across the country to fight day and night to overcome the difficulties of two-line hybrid rice. After nearly a year's efforts, super hybrid rice was successfully planted in a small area, with a yield of 800 kilograms per mu, and was successfully introduced in Southwest Agricultural University and other places. At present, super hybrid rice is heading for large-scale trial planting and popularization.
Related terms
Male sterile line: It is a kind of female rice with male degeneration (mainly pollen degeneration) but normal pistil. Because pollen can't live, it can't pollinate and bear fruit by itself, and it can only be fertilized and borne by exotic pollen. Therefore, with this mother rice as a genetic tool, a large number of hybrid seeds can be produced by artificial pollination.
Maintainer: It 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 line: It is a normal rice variety. 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 three-line 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: a kind of rice named photo-thermo-sensitive sterile line, whose fertility transformation is closely related to the length of sunshine and temperature, and it 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 under the condition of 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 hybrid rice: Super high-yield rice breeding 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).
Breeding technical route of super hybrid rice
(1) Two lines and three lines developed synchronously, and morphological improvement was combined with the utilization of heterosis among subspecies.
(2) For the middle and lower reaches of the Yangtze River, build an excellent plant-type hybrid rice combination with high canopy height, short panicle layer, low center of gravity, large and uniform sink and high lodging resistance; Aiming at the single-season rice area in southwest China, the combination of heavy panicle hybrid rice between subspecies was selected.
(3) Using indica-japonica heterosis to select parents, and using interspecific heterosis.
(4) Using distant beneficial genes with the help of biotechnology.
(5) According to the characteristics of super hybrid rice, the cultivation techniques of super high yield were established.
Fertilization method for hybrid rice
According to the determination of basic application amount of organic fertilizer, 50%-60% of nitrogen and 70% of phosphorus and potassium in the total fertilizer requirement of hybrid rice come from soil. Insufficient fertilization will consume too much nutrients in the soil and reduce fertility. Increasing application of organic fertilizer is an important way to improve fertility. Therefore, in hybrid rice production, the application amount of organic fertilizer should account for 40% of the total fertilization amount.
Tillering fertilizer can be applied to early rice 5 days after transplanting and to late rice 3 days after transplanting. Tillering fertilizer should be applied in stages. For the first time, 6-7.5 kilograms of urea should be applied per mu, and every 7 days or so, according to the seedling situation, 4 kilograms of urea should be applied per mu to the fields with poor growth; 5-7.5 kilograms of potassium fertilizer should be applied to the land with little organic fertilizer and potassium deficiency per mu.
According to the different application time, ear fertilizer can be divided into flower-promoting fertilizer and flower-keeping fertilizer. Where fertilization is suitable in the early stage and the seedlings are in good condition, flowers are generally protected and grains are increased, only flower protection fertilizer is applied, and about 2.5 kilograms of urea is applied per mu. If there is insufficient fertilization in the early stage, the number of seedlings in the group is small and the individual growth is poor, it is necessary to apply both flower-promoting fertilizer and flower-protecting fertilizer, and apply 5 kg of urea per mu each time. Hybrid rice has a great demand for potassium fertilizer, so it should be combined with topdressing nitrogen fertilizer after the sun rehydrates, and topdressing potassium fertilizer is about 2.5 kg per mu.
Before heading with granular fertilizer, look at the fields with too light seedlings, and apply 22.5 kilograms of urea per mu; Apply 2.5-3 kg urea per mu to the land that falls yellow prematurely after full heading; For normal growing fields, 50 kg of water and 5-7.5 kg of urea should be sprayed per mu. Because of the great demand for phosphorus and potassium in the late growth stage of hybrid rice, it is necessary to use 150-200 grams of potassium dihydrogen phosphate per mu, and spray 50 kilograms of water 4-6 days before heading or 2-3 days after heading.
Super-high yield plant type model of rice
Plant height: 100 cm
Stem height: 75 cm
Tillering ability: medium.
Plant type: moderately compact
The upper three leaves: long, straight, narrow, concave and thick.
Spike type: drooping
Ear number: 2.7 million/ha
Single ear weight: about 5 grams
Harvest index: 0.55
Daily output: 100 kg/ha
Utilization of heterosis among subspecies
There are two subspecies of rice: indica rice and japonica rice. Theoretically, the yield of intersubspecific hybrid rice can be increased by more than 30%.
At present, the main problems in the utilization of heterosis among subspecies have been basically solved. The newly bred super hybrid rice between subspecies has large panicles and many grains, and good quality, which has increased the yield by more than 20% compared with the existing hybrid rice in production test and demonstration.
Yuan Longping-the Father of Hybrid Rice in the World
Farmers in China said that eating depends on "two levels", Deng Xiaoping (responsibility system) and Yuan Longping (hybrid rice). According to the western world, hybrid rice is "Oriental magic rice". His achievements not only solved the problem of eating in China to a great extent, but also were regarded as the magic weapon to solve the world hunger problem in the next century. Internationally, hybrid rice is even regarded as the fifth great invention of China after the four great inventions, which is called the "second green revolution".
Yuan Longping,/kloc-0, born on September 7th, 930, is an academician of China Academy of Engineering. He is currently the director of the National Hybrid Rice Work Technology Center, the Hunan Hybrid Rice Research Center and the vice chairman of the Hunan Provincial Political Consultative Conference. China, the founder of hybrid rice research, was the first person in the world to successfully utilize the heterosis of rice. Yuan Longping has been engaged in the theoretical research of hybrid rice breeding and the practice of seed production technology for a long time. 1964 first put forward the idea of cultivating "sterile line, maintainer line and restorer line" to make use of rice heterosis, and carried out scientific experiments. 1970, he and his assistants Li Bihu and Feng Keshan discovered a male sterile wild rice in Hainan, which became the key to break through the "three lines" matching. 1972 bred the first rice male sterile line "Erjiunan 1 A" and the corresponding maintainer line "Erjiunan 1 B" in China, and bred the first strong combination "Nanyou No.2" in the following year, and studied a set of seed production techniques. 1986 puts forward the strategic assumption that hybrid rice breeding is divided into "three-line method using interspecific heterosis, two-line method using interspecific heterosis and one-line method using distant heterosis". Known as "the father of hybrid rice" by peers.
He has successively won the Gold Award for Outstanding Inventor of the United Nations Intellectual Property Organization, the UNESCO Science Award, the Jean-Claude Award of the Jean-Claude Foundation of the United Kingdom, the World Hunger Saving Award of the Fanster Foundation of the United States, the Food safety award of the United Nations Food and Agriculture Organization, the Nikkei Asia Award of Japan, the Pioneer Scientist Award for Utilization of Crop Heterosis, and the Yue Guang International Rice Award of Japan.
Enlightenment of hunger
From 65438 to 0960, there was a nationwide famine in China, and Yuan Longping and his students were also threatened by hunger.
On one occasion, he took more than 40 agricultural school students to build a brigade in Xizhou Commune, Qianyang County to participate in productive labor. One day, the landlord always came back with a load of rice in the rain. He told Yuan Longping that this is the rice he bought from another village.
"Why do you want to change rice seeds?" Yuan Longping asked.
"There is a high slope open space, full of food and high yield. Fertilization is not as good as diligent planting. " Lao Xiang said, "Last year we used the rice seeds we bought there, and the yield in the field increased. We didn't eat the grain that the country sold back this year. "
In the face of famine, villagers did not wait for state relief, but took the initiative to find ways to increase production. Yuan Longping was very moved.
This incident inspired him greatly: improving varieties and increasing production is of great significance to overcoming hunger. He thought that in addition to teaching good classes, he should also make some achievements in agricultural scientific research and cultivate good seeds with high yield for fellow villagers.
Principle of increasing yield of hybrid rice in Yuan Longping
Hybrid rice 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 emasculated or killed artificially, and then the stamen pollen of the other variety should be given to the emasculated variety, so that there will be no false hybrid rice which is self-pollinated by the emasculated variety. However, if tens of thousands of nectarine 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 hybrid rice we need, a female parent and its two objects. According to their different characteristics, people have given three names respectively: the female parent is called sterile line, and two objects, one is called maintainer line and the other is called restorer line, which is called "three lines" for short. With the "three-line" system, we know the preparation of hybrid rice in production: a breeding field and a seed-making field should be planted in production, and a sterile line and a maintainer line should be planted in the breeding field. When both flowers bloom, the pollen of the maintainer line will be transferred to the sterile line by the wind, and the sterile line will get normal pollen results, and the offspring will still be sterile, thus achieving the purpose of breeding the sterile line. We can keep a part of the propagated sterile line seeds for further propagation in the next year, 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 will be transferred to the sterile line, and the offspring produced by the sterile line will be 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.
Magazine of the same name
Hybrid Rice is the only professional technical publication in hybrid rice field at home and abroad so far. With the aim of "promoting the pioneering research and development of hybrid rice, transforming the research results into productive forces as soon as possible, promoting the continuous development of hybrid rice research and production, and better serving China's socialist modernization", we adhere to the publishing policy of "combining popularization with improvement, focusing on improvement". The publication covers all aspects of research, development and application of hybrid rice, integrating academics, technology, popularization and information. It has successively set up special topics and reviews, breeding and breeding, breeding and seed production, cultivation techniques, basic theories, new combinations, translation, briefings, newsletters, foreign trends, rice quality, academic contention and special reports. It has been distributed to all provinces (cities, districts) with rice cultivation in China, and has been distributed to the United States, India, Vietnam and other countries and regions 10. Readers are agricultural scientists and technicians, teachers and students in agricultural colleges, agricultural production and management personnel and knowledge farmers.
In the 1970s, a major invention of agricultural science and technology in China, hybrid rice, opened a new page in the history of rice production, making China the first country in the world to successfully cultivate hybrid rice and apply it to production on a large scale. This achievement led by Yuan Longping won 198 1 China's only national special invention award so far. By the end of 1999, China had planted more than 200 million hectares of hybrid rice, increasing the rice yield by more than 300 billion kilograms. The wide application of hybrid rice has greatly increased rice yield and made indelible contributions to solving the problem of food self-sufficiency in China with a population of more than one billion. Hybrid Rice magazine has played an important role in promoting the continuous development of hybrid rice through the promotion of achievements, information exchange and knowledge dissemination.
In the mid-1980s, hybrid rice was in a period of rapid development. In order to adapt to the development of hybrid rice, further promote the continuous development of hybrid rice scientific research and production, and accelerate the transformation of scientific research results into practical productivity, the National Hybrid Rice Research Cooperation Group planned to establish Hybrid Rice magazine at the acceptance meeting of scientific and technological research results in the Sixth Five-Year Plan held in Changsha in September, 1985. In the same year, on June 5438+065438+1October, with the approval of Hunan provincial science and technology commission, the press and distribution department of Hunan Publishing Bureau registered (registration number 136), and hybrid rice was published on February 1986, marking its official publication. At the same time, the editorial board of Hybrid Rice was formally established.
When Hybrid Rice was first published, it was sponsored by the President of Hunan Academy of Agricultural Sciences, the National Hybrid Rice Research Cooperation Group and the Hunan Hybrid Rice Research Center. Quarterly, 16 format, 48 pages, limited to domestic and self-issuance. 1988, changed to bimonthly, and obtained the domestic standard publication number CN43- 1 137, changed to post office, and the postal code was 42-88. 1989, retransmitted by itself; English catalogues have been added, and some papers have provided English abstracts. 1993 began to be publicly issued abroad, and the foreign code was BM 4416; ; On September 28th of the same year, it was awarded the serial publication number of international standard (ISSN1005-3956); All articles have English contents and titles, and the main papers have English abstracts and charts, which are gradually standardized according to relevant national standards. From 65438 to 0996, the organizers were changed to National Hybrid Rice Engineering and Technology Research Center and Hunan Hybrid Rice Research Center, and the members of the editorial board of Hybrid Rice were appropriately adjusted. 1997, change the color cover. 200 1, from 48 pages to 64 pages. In 2003, it was changed to 16 (285 mm * 2 10 mm) format, and the number of pages increased from 64 to 80 from the second issue of that year. In 2005, it was issued by the post office with the postal code of 42-297.
Patent distribution of hybrid rice
American hybrid rice patent documents 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. Judging from the current 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.
From the technical content, the patent documents of hybrid rice published by the parties in China are mainly distributed in the following fields:
First, cross breeding methods. This kind of literature accounts for the majority. For example, the document CN97 107703.7 relates to a new hybrid rice breeding and seed production technology. Belonging to a new technology for utilizing heterosis between indica and japonica subspecies. The breeding and stability of indica-japonica restorer lines with high heterozygosity and strong heterosis in the next generation were highlighted. The purpose of utilizing indica-japonica heterosis was achieved through their male gametes, and the contradiction between seed setting rate and heterosis in F 1 generation was solved. On this basis, a series of indica-japonica hybrid combinations with high yield, high quality and multi-resistance were combined, which increased the yield by about 15% in a large area, effectively realizing the heterosis among indica-japonica subspecies.
The document CN00 134536.2 relates to a hybrid rice seed production method. According to the initial sowing calendar and flowering calendar of parents, it arranges the difference and time difference of sowing leaves of parents, cultivates parents, synchronizes the full flowering period of parents, and creates the best outcrossing situation through fertilization and chemicals. Induce the female parent to enter the sensitive period of stigma exposure, and use chemical fertilizer to improve the pollen viability of the male parent; Artificial pollination is carried out at the peak of male pollen transmission.
The document CN02 104889.4 relates to a mechanized seed production method of three-line hybrid rice. Firstly, a rice variety with different shell color is selected and hybridized with a rice maintainer line variety with normal shell color to obtain a rice maintainer line seed with different shell color, and then a rice sterile line seed with different shell color is transferred; Secondly, the hybrid seeds with different shell colors and the restorer seeds with normal shell colors are mechanically mixed and sown, and the powder is mechanically driven at flowering stage; after fruiting, the hybrid seeds with different shell colors and the selfing restorer seeds with normal shell colors are mechanically mixed, and then sorted by a color sorter to obtain hybrid seeds and restorer seeds respectively.
The document CN2005 10040408.2 relates to a rice breeding method for rapidly polymerizing excellent genes. It hybridizes two rice materials with different excellent genes to obtain F 1 hybrid; Anther culture of F 1 hybrid was carried out to obtain a stable flower culture line; Screening the characters of stable flower culture lines to obtain rice materials with excellent genes polymerized.
Second, transgenic hybridization. For example, the document CN2003 10 107230. X relates to a production method of multi-resistant transgenic hybrid rice seeds. It transfers herbicide-resistant genes and borer-resistant genes into the restorer line of three-line hybrid rice or two-line hybrid rice, so that the restorer line can obtain herbicide-resistant genes and borer-resistant genes, which have herbicide-resistant characteristics and borer-resistant characteristics; The rice planthopper resistance gene was transferred into the maintainer line of three-line hybrid rice, so that the maintainer line obtained the rice planthopper resistance gene, which had the characteristics of rice planthopper resistance. By crossing the sterile line with the maintainer line, the sterile line obtained the rice planthopper resistance gene, which has the characteristics of rice planthopper resistance; Then the obtained transgenic restorer line is hybridized with the transgenic sterile line to produce hybrid rice seeds. This technology can improve the purity and insect resistance of hybrid rice. The document CN2005 10044823.5 relates to a new rice variety breeding method combining gene double guidance and hybridization. The target characters were obtained by gene gun method and Agrobacterium tumefaciens infection method. Such as disease-resistant and insect-resistant transgenic rice germplasm materials, combined with conventional rice breeding techniques such as hybridization and molecular marker-assisted selection, to cultivate new rice varieties with multi-objective characteristics. Document CN97 1098 14. X relates to a production method of hybrid rice seeds. A herbicide-resistant gene is transferred into a restorer line of a three-line hybrid rice or a two-line hybrid rice, so that the restorer line can obtain the herbicide-resistant gene with herbicide-resistant characteristics, and then the obtained transgenic restorer line is hybridized with a three-line sterile line or a two-line sterile line to produce hybrid rice seeds. It can improve the purity of hybrid seeds and eliminate false hybrid plants in time.
Third, the method of purity identification and assurance. For example, the document CN99 103 138.5 relates to a method for quickly and accurately identifying the purity of hybrid rice sterile lines and hybrid seeds. Including seed treatment, DNA sample preparation, polymerase chain reaction, polyacrylamide gel electrophoresis, silver nitrate staining and result observation. The document CN200310106119.9 relates to a method for ensuring seed purity in two-line hybrid rice seed production. It solves the problem that the continuous low temperature of the female parent in the fertility sensitive period will affect the purity of hybrid rice seed production. The method is as follows: When the average daily temperature is lower than 23.5℃ 5 ~ 15 days before heading in the seed-making field, use irrigation water with water temperature higher than 25℃ for series irrigation or deep irrigation 10 cm above, and the temperature of the drainage outlet is not lower than 24℃. When the temperature rises to 23.5℃, drain the accumulated water in the field. The document CN2004 10002369.2 relates to a method for seed retention of hybrid rice. It takes the hybrid rice sterile line with albino-to-green-leaf color marker as the core material to realize "double" efficient impurity removal, that is, in the process of reproduction and seed production, the first impurity rearrangement is realized by removing the green impure sterile line parent seedlings in the albino sterile line in the rice seedling field; When the hybrid with albino marker is used in the field, the albino seedlings can be eliminated manually in the rice field, or the albino seedlings are obviously weaker than the hybrid. False hybrids (especially albino self-bred seedlings) can be eliminated naturally through growth competition before transplanting, and automatically eliminated when the seedlings are pulled out, thus realizing the secondary rearrangement of the hybrid. The document CN02 1535 18.3 relates to a new method for seed purity identification of hybrid rice. According to the color marks of green leaves, conventional indoor and outdoor germination tests or seedling field sowing tests are carried out. When the seedlings grow to 1-3 leaf stage, the hybrid proportion of sterile lines in hybrid F 1 was identified by identifying the seedlings with leaf color markers in normal green seedlings. By identifying the normal green seedlings among the seedlings with leaf color markers, the proportion of cross-pollinated seeds of sterile lines was identified. According to the method of the invention, in the field production, according to the purity of seedlings, measures of manually assisting in eliminating seedlings with leaf color markers or automatically arranging jia ye are implemented to ensure the purity of hybrids; In the field of sterile line propagation and seedling production, normal green seedlings are artificially eliminated according to the purity of seedlings to ensure the seed purity of sterile lines and hybrids.
Fourth, the method of stabilizing heterosis. For example, the document CN98112551.4 relates to a method for fixing the advantages of hybrid rice. It uses asexual propagation to continuously propagate the seeds of the first generation of hybrid rice for three years 15-20 generations, and then uses sexual propagation for breeding for 2-3 years, so as to obtain a combination that not only has the high yield advantage of hybrid rice, but also can be propagated by farmers themselves like conventional rice.