Method for breeding hybrid rice with high seed production purity
By breeding new two-line sterile lines and new three-line sterile sterile lines with three-line retaining genes, and hybridizing with restoration lines, the problem of difficult purity of the three-line and two-line hybrid rice in the prior art is solved, and high purity and high yield hybrid rice seed preparation is achieved.
Patent Information
- Application Number
- CN202510433989.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-13
AI Technical Summary
It is difficult for the existing three-line and two-line hybrid rice to achieve high purity during the seed production process, especially during the reproduction of three-line sterile lines, unqualified batches of seeds often occur due to transplantation and miscellaneous plant types. In addition, the two-line hybrid rice can easily cause low seed purity in low temperature weather, resulting in significant losses.
By breeding new two-line sterile lines and new three-line sterile sterile lines with three-line retaining genes, combined with pedigree selection and intercourse technology, stable new two-line sterile lines and new three-line sterile lines were selected and hybridized with the restorative line to improve seed purity and yield and reduce seed production costs.
The high-purity seed production of three-line hybrid seeds has been achieved, the purity stability of the two-line hybrid seeds under low temperature conditions has been improved, the cost and risk of seed production has been reduced, and the commerciality of seeds and farmers' income has been improved.
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Figure CN120130362A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical fields of rice breeding and seed production, and particularly relates to a method for breeding hybrid rice with high seed production purity. Background Art
[0002] Currently, the popularized hybrid rice mainly includes three-line and two-line hybrid rice. During the propagation process of the three-line hybrid rice sterile line, it is necessary to strictly arrange the paired crossing of the maintainer line and the male sterile line to expand and propagate the original seed purity (above 99.9%). When using the original seed to propagate the three-line female parent seeds in the field for seed production, the required purity is above 99.5%. During the propagation process of the female parent seeds, operating according to the operation regulations for the propagation of the three-line sterile line, it is very difficult to achieve a qualified purity of 99.9% for the three-line sterile line female parent. During the actual propagation process of the female parent seeds, unqualified batches of seeds often occur due to processes such as transplanting and harvesting of the maintainer line caused by the main types of miscellaneous plants of the maintainer line. Due to this characteristic of the three-line sterile line, it is very difficult to achieve a purity of more than 99% for the three-line hybrid seeds produced in the field from the qualified three-line female parent seeds propagated. For the seed production of two-line hybrid rice, under normal weather conditions, the purity of the hybrid seeds produced can easily reach more than 99%. However, during the seed production process of two-line hybrid rice, if continuous low-temperature weather occurs during the fertility sensitive period, the seed purity is low due to the reversion of the female parent, and it is very easy to produce scrapped seeds, resulting in significant losses.
[0003] Moreover, during the propagation process of the three-line female parent seeds, only the sterile line is harvested, and 20% of the maintainer line cannot be utilized. Therefore, the propagation yield of the three-line sterile line is low, generally about 150 - 200 kg, and the propagation cost of the three-line sterile line is high. The propagation yield of the two-line female parent seeds is generally above 400 kg, and the propagation cost is low. In addition, the combining ability of the three-line sterile line is worse than that of the two-line sterile line. Summary of the Invention
[0004] The purpose of the present invention is to provide a method for breeding hybrid rice with high seed production purity in order to solve the above problems.
[0005] The present invention achieves the above purpose through the following technical solutions:
[0006] A method for breeding hybrid rice with high seed production purity, including female parent selection and hybrid seed production. The female parent is selected by at least one of the following methods (1) and (2):
[0007] (1) Hybridize a two-line sterile line with a three-line maintainer line, and through pedigree selection, simultaneously use the test cross method of the three-line sterile line to breed a new two-line sterile line with the target traits of the three-line maintainer gene. At the same time, select a place suitable for the propagation of two-line seeds, and continuously self-cross the new two-line sterile line with the maintainer gene until a stable new two-line sterile line with the maintainer gene is selected. This new two-line sterile line with the maintainer gene can also be used as the maintainer line for the two-line sterile line
[0008] (2) Hybridize a two-line sterile line with a three-line maintainer line, and through pedigree selection, while using the test-cross method of the three-line sterile line, breed a new two-line sterile line with the target traits of the three-line maintainer gene; Test-cross the three-line sterile line with the newly bred two-line sterile line to obtain the F1 generation, determine the lines of the new two-line sterile line that have the sterile gene maintaining the three-line sterile line through test-cross, and conduct consecutive backcrosses until the three-line sterile line is stable, and breed a stable new three-line sterile line;
[0009] The method for hybrid seed production described above includes:
[0010] Hybridize the new two-line sterile line with a maintaining gene selected by method (1) with a restorer line for hybrid seed production. Under normal weather conditions, high-purity two-line hybrid seeds can be obtained; or,
[0011] Hybridize the new three-line sterile line selected by method (2) with a restorer line for hybrid seed production, thereby obtaining high-purity three-line hybrid seeds without maintainer and sterile line hybrid plants; or,
[0012] Arrange the new two-line sterile line with a maintaining gene selected by method (1) and the new three-line sterile line selected by method (2) to use the same male parent for seed production at the same time. When the two-line fertility sensitivity period encounters low-temperature conversion, the seeds produced by the two-line and the seeds produced by the three-line are mixed to solve the risk of unqualified purity caused by low-temperature conversion in two-line seed production.
[0013] As a further optimized scheme of the present invention, the two-line sterile line is selected as Xin'an S; the three-line maintainer line is selected as Quanxiang 9B; the three-line sterile line is selected as Quanxiang 9A, but not limited to this, and other two-line or three-line varieties can be applied to the breeding method of the present invention.
[0014] As a further optimized scheme of the present invention, the restorer line is selected as YR9085, but not limited to this, and other restorer lines are also applicable to the breeding method of the present invention.
[0015] As a further optimized scheme of the present invention, during the breeding process, select lines whose plant leaf morphology, grain type, plant height, spike grain number and other traits all tend to the three-line maintainer line, and select lines with a high stigma exsertion rate for the new two-line sterile line.
[0016] As a further optimized scheme of the present invention, during the continuous self-crossing or continuous backcrossing process, select individual plants with excellent comprehensive traits to continue backcrossing or self-crossing.
[0017] As a further optimized scheme of the present invention, the excellent comprehensive traits include strong maintaining ability, strong combining ability and obvious heterosis.
[0018] As a further optimized scheme of the present invention, the number of consecutive self-crossing and backcrossing is at least 7 times.
[0019] The present invention also provides an application of a new two-line male sterile line with a maintaining gene selected by the above method in the breeding of hybrid rice, and the application includes but is not limited to using it for the breeding of hybrid rice or modifying it.
[0020] The beneficial effects of the present invention are as follows:
[0021] 1) In the process of traditional three-line hybrid rice seed production, the maintainer line often mixes into the male sterile line, making it difficult to remove impurities and it is very difficult to produce seeds with a high purity of about 99%. The new three-line male sterile line (with the traits of the three-line maintainer line) and the new two-line male sterile line with a maintaining gene (also serving as the maintainer line of the two-line male sterile line) developed by the method of the present invention can be respectively used to produce hybrid seeds with the restorer line, solving the technical problem that the three-line seeds cannot reach the high-purity hybrid rice seeds under normal weather conditions of the two-line system, and the seed production purity can be increased to more than 99.0%. The purity requirement for field-use hybrid rice seeds in the newly revised GB4404.1-2024 has been increased to the standard of 97%. The high-purity hybrid rice seeds obtained by the technology of the present invention can well guarantee and improve the commerciality of hybrid rice seeds.
[0022] 2) In the process of traditional two-line hybrid rice seed production, continuous low-temperature weather during the production of two-line seeds is likely to cause unqualified seeds, and the risk of transformation during low-temperature is relatively high. When the new three-line male sterile line (with the traits of the three-line maintainer line) and the new two-line male sterile line with a maintaining gene (also serving as the maintainer line of the two-line male sterile line) developed by the method of the present invention are used to produce hybrid seeds with the restorer line, the risk of transformation of two-line rice seeds during low-temperature can be reduced, the direct losses of seed producers and seed companies can be reduced, and the benefits of seed companies and the income increase of farmers can be indirectly improved.
[0023] 3) In the process of traditional three-line hybrid rice seed production, the three-line maintainer line and the three-line male sterile line need to be harvested separately, but the new two-line male sterile line with a maintaining gene (also serving as the maintainer line of the two-line male sterile line) developed by the method of the present invention can increase the yield and reduce the seed propagation cost of the three-line female parent.
[0024] 4) The new two-line male sterile line with a maintaining gene (also serving as the maintainer line of the two-line male sterile line) developed by the method of the present invention can improve the freedom of combination of the male sterile line. Description of the Drawings
[0025] Figure 1 Specific technical route diagrams for obtaining 22A496 (a new three-line male sterile line with the traits of the three-line maintainer line) and 22BS496 (a new two-line male sterile line with a maintaining gene, also serving as the maintainer line of the two-line male sterile line) by the method of the present invention. Detailed Embodiments
[0026] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.
[0027] 1. Materials
[0028] 1) Xin'an S comes from Anhui Quanyin Hi-Tech Seed Co., Ltd.;
[0029] 2) Quanxiang 9B, Quanxiang 9A, YR9085 and YR1606 are all from Anhui Quanyin Hi-Tech Seed Co., Ltd., and YR985 is from Anhui Quanyin Seed Technology Co., Ltd.;
[0030] 3) Wushan Silk Rice comes from the Rice Research Institute of Guangdong Academy of Agricultural Sciences;
[0031] The methods used in this example are conventional methods known to those skilled in the art unless otherwise specified, and the reagents and other materials used are commercially available products unless otherwise specified.
[0032] 2. Methods
[0033] This embodiment provides a method for breeding high-purity hybrid rice, and its technical route is as follows: Figure 1 As shown, the following steps are included:
[0034] (1) In the spring of 2016, the two-line sterile line Xin'an S and the three-line maintainer line Quanxiang 9B were hybridized in Sanya; the F1 generation was then planted in Sanya, Hefei and other places and self-pollinated continuously. Pedigree selection was adopted to mix seeds and select excellent sterile plants with target traits such as plant leaves and grain shape that were closer to Quanxiang 9B and with a high stigma leakage rate. A total of 21 lines, 19BS01-21, were obtained, which are new two-line sterile lines with the target traits of the three-line maintainer gene;
[0035] (2) In the 2018 Hefei season, the three-line sterile line Quanxiang 9A and the new two-line sterile line 19BS01-21 were tested and cross-bred to obtain the F1 generation. It was found that the new two-line sterile line 19BS01 had a sterility-maintaining gene for Quanxiang 9A. 19BS01 was backcrossed for many generations until it was stable, and a new three-line sterile line 22A496 with the three-line maintenance gene was obtained. At the same time, a place suitable for two-line seed propagation was selected, and 19BS01 was self-pollinated for many generations until it was stable, and a stable new two-line sterile line (also used as the maintenance line of the two-line sterile line) 22BS496 with the maintenance gene was obtained;
[0036] (3) The selected 22A496 was hybridized with YR9085, Wushan Si Miao, YR1606, and YR985. The agronomic traits of 22A496 / YR9085 were as follows: field purity was as high as 99.7%, growth was luxuriant, plant height was 119 cm, number of grains per ear was 324, fruit set rate was 89.2%, 1000-grain weight was 25.2 g, and yield was 4.6% higher than that of Feng Liang You No. 4.
[0037] In the summer of 2022, YR9085 (male parent) was used to produce seeds on a small scale with 22A496 and 22BS496. The female parents were uniform and consistent without any difference, and the outcrossing was strong. The seed production yields were 209 kg and 204 kg / mu, respectively. The hybrids produced were planted in the winter of 2022 and the summer of 2023. There was no difference between the plants, and the populations were uniform. In the winter of 2023, at the Hainan South Breeding Base, 22A496 / 22BS496 were bred in a small scale by conventional and mixed planting and harvesting. According to the three-line breeding, the yield per mu of the new three-line sterile line female parent reached 172 kg, and the yield per mu of the single-harvest maintenance line that also served as a two-line sterile line reached 103 kg, with a total of 275 kg; the direct breeding of 22BS496 yielded 417 kg per mu, both of which met the expected goals; this proves that the method of the present invention is practical and feasible, has great application value, and is worthy of promotion.
[0038] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.
Claims
1. A method for breeding high-purity hybrid rice, comprising breeding of female parents and hybrid seed production, characterized in that: The female parent is selected by at least one of the methods (1) and (2): (1) hybridizing a two-line sterile line and a three-line maintainer line, selecting a new two-line sterile line with the target trait of the three-line maintainer gene by pedigree selection and test crossing of the three-line sterile line, and selecting a place suitable for two-line seed propagation to continuously self-pollinate the new two-line sterile line with the maintainer gene until a stable new two-line sterile line with the maintainer gene is selected; (2) hybridizing a two-line sterile line with a three-line maintainer line, and breeding a new two-line sterile line with the target trait of the three-line maintainer gene by pedigree selection and test crossing of the three-line sterile line; testing the three-line sterile line with the new two-line sterile line obtained by breeding to obtain the F1 generation, determining the strain of the new two-line sterile line with the sterility maintenance gene for the three-line sterile line through test crossing, and continuously backcrossing until the three-line sterile line is stable, thereby breeding a stable new three-line sterile line; The hybrid seed production method comprises: By hybridizing the new two-line sterile line with the maintenance gene selected and bred by method (1) with the restorer line, high-purity two-line hybrids can be obtained under normal weather conditions; or The new three-line sterile line bred by method (2) is hybridized with the restorer line to produce seeds, thereby obtaining a high-purity three-line hybrid seed without hybrid plants of the maintainer line and the sterile line; or, The new two-line sterile line with the maintenance gene bred by method (1) and the new three-line sterile line bred by method (2) are arranged to produce seeds with the same male parent at the same time. When the two-line fertility sensitive period encounters low temperature transformation, the seeds produced by the two-line and the seeds produced by the three-line are mixed to avoid the risk of purity failure caused by low temperature transformation of the two-line seed production.
2. The method for breeding high-purity hybrid rice according to claim 1, characterized in that: The two-line sterile line is Xin'an S, the three-line maintainer line is Quanxiang 9B, and the three-line sterile line is Quanxiang 9A.
3. The method for breeding high-purity hybrid rice according to claim 1, characterized in that: The recovery line selected is YR9085.
4. The method for breeding high-purity hybrid rice according to claim 1, characterized in that: During the breeding process, the plant and leaf morphology, grain type, plant height, and number of grains per ear were all biased towards the three-line maintainer line, and the new two-line sterile line selected the plant line with a high stigma exposure rate.
5. The method for breeding high-purity hybrid rice according to claim 1, characterized in that: During the continuous self-pollination or continuous backcrossing process, individual plants with excellent comprehensive traits are selected for further backcrossing or self-pollination.
6. The method for breeding high-purity hybrid rice according to claim 5, characterized in that: The comprehensive traits include strong maintaining ability, strong matching ability and obvious hybrid advantages.
7. The method for breeding high-purity hybrid rice according to claim 1, characterized in that: The number of continuous self-pollination and backcrossing is at least 7 times.
8. Application of a two-line sterile line with a maintenance gene in hybrid rice breeding, characterized in that: The two-line sterile line having the maintainer gene is prepared by the method (1) as claimed in claim 1.