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 all 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. Which belongs 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.
Document CN.2 relates to a rice breeding method for rapid polymerization of 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 CN2X document relates to the 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 CN2.5 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 CN9.5 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. Document CN2.9 relates to the method of ensuring seed purity in hybrid rice seed production by two-line method. 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: 5 ~ 15 days before heading in seed field, when the daily average temperature is lower than 23.5℃, irrigation water with water temperature higher than 25℃ is used for series irrigation or deep irrigation 10 cm or more, and the temperature of the drainage outlet is not lower than 24℃. After the temperature rises to 23.5℃, the accumulated water in the field is discharged. The document CN2.2 relates to a method for removing jia ye from 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, document CN9.4 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, thus obtaining a combination that not only has the high yield advantage of hybrid rice, but also can be propagated by farmers themselves like conventional rice.