Method for creating japonica-deviated restorer line by using rice recessive genic male sterility

Abstract

The invention discloses a method for creating a japonica-deviated restoring line by using rice recessive genic male sterility, which comprises the following steps: taking a Sanming recessive genic male sterility material with wide affinity as a female parent; the method comprises the following steps: carrying out mixed pollination hybridization by taking excellent indica type restorer lines such as' Minghui 164 'and' Fughui 676 ', long-grain fragrant conventional indica type rice, indica japonica intermediate type wide-compatibility restorer lines and japonica rice as core parents to obtain F1 seeds; bC3F3 seeds are finally obtained through continuous selection and backcross processes in combination with rice blast seedling stage pressure identification, selection of specific characters and application of a program index method; through specific single plant selection and test cross experiments, and finally through multi-generation breeding and identification, the japonica-clone restorer line with good plant leaf morphology, moderate growth period, strong lodging resistance, sufficient pollen amount, wide affinity, strong restoring force and good combining ability is obtained. According to the method, the problems of low yield and high seed cost of combined seed production of indica-japonica intersubspecific hybrid rice are solved, and the economic benefits of seed production households are improved.

Description

Technical Field

[0001] The invention relates to the technical field of rice breeding, in particular to a method for creating a japonica-type restorer line by utilizing recessive nuclear sterility of rice. Background Art

[0002] Rice is one of the most important food crops for human beings. About 60% of the population in my country relies on it as their staple food. Its yield and quality are crucial to ensuring my country's food security. With the growth of population, there is an urgent need to increase the yield of rice per unit area to ensure food demand. The hybrid vigor between rice subspecies is strong. The discovery of wide-compatibility genes has laid a theoretical foundation for the utilization of hybrid vigor between indica and japonica subspecies. By using the pairing mode of japonica sterile lines and indica-japonica intermediate wide-compatibility restorer lines, hybrid combinations between indica and japonica subspecies have been formulated, such as the "Yongyou Series" and "Chunyou Series". These hybrid combinations have shown strong yield advantages, good plant and leaf morphology, smooth color change in the late growth period, and rapid development. More than 120 varieties have been cultivated, with an annual application area of ​​over 10 million mu. However, there are problems such as low combined seed production yield and high seed cost. In recent years, South China Agricultural University and Sanming Academy of Agricultural Sciences have made major progress in the "indica-non-japonica restorer" model, which is expected to solve the problems of low hybrid rice seed production yield, high seed cost, rice storage intolerance, and serious rice smut disease between indica and japonica subspecies. Therefore, adopting the "indica but not japonica restorer" pairing model, moderately introducing key japonica rice bloodlines based on the genetic background of the existing comprehensive trait excellent restorer lines, and expanding the genetic background differences between hybrid rice parents will be a major direction for hybrid rice variety improvement in the future.

[0003] Rice is a self-pollinating crop, and the selection and breeding of restorer lines is mainly carried out through artificial emasculation and hybrid breeding. Limited by artificial hybridization technology and breeding cycles, only a few parents are often used for hybridization during the breeding process. Although short-term breeding goals can be achieved quickly, it is easy to lead to a narrow genetic basis of the bred varieties and serious variety homogeneity. At present, there are new requirements for rice yield, rice quality, stress resistance and simplified cultivation in production. Breeding goals are constantly changing. Traditional breeding methods can hardly meet the needs of agricultural production. Therefore, it is imperative to break the routine and seek new breeding methods. Recurrent selection is a cyclical population improvement method. Through the cycle of "selection-recombination-reselection-recombination", the frequency of favorable genes in the population gradually increases, which can achieve the purpose of improving the target traits in the population. It has the advantages of breaking the linkage of unfavorable genes and fully carrying out gene exchange and recombination. Breeding practice has proved that recurrent selection is the most effective method for crop population improvement and germplasm innovation, especially for the improvement of multiple complex agronomic traits at the same time, such as corn and wheat, which have made great achievements in population improvement. The exploration of rice recurrent selection breeding began with the discovery of male sterile materials. Recurrent selection breeding in rice with the help of nuclear sterile genes can create many excellent varieties and intermediate breeding materials. For example, Sichuan Agricultural University used Sichuan recessive nuclear sterile rice for recurrent breeding to breed a high-combining restorer line Shuhui 498. Zou Wenguang and others from Sanming Academy of Agricultural Sciences found 14 sterile plants among 40 plants of the gk1085 line of the F5 generation of hybrid offspring of the indica-japonica hybrid intermediate material Minghui 1328 and the double-resistant Mingzhan. The anthers and filaments were small and white, and the anthers did not crack. They belonged to the pollen-free male sterility, with a high stigma exposure rate and a high cross-pollination fruiting rate. After years of observation and identification, it was preliminarily confirmed that the sterile plant was recessive male nuclear sterile. The expression of the sterile gene was not affected by environmental factors and had a wide affinity. It was named Sanming recessive nuclear sterile. This recessive nuclear sterile material is an ideal germplasm for the cyclic selection of indica-japonica restorer lines. It can be used to establish an efficient cyclic selection breeding population, broaden the genetic basis of hybrid rice restorer lines, and overall improve the resistance, quality, stress resistance, and yield combining ability of existing restorer lines. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a method for creating a japonica-type restorer line by utilizing recessive nuclear sterility of rice.

[0005] In order to solve the above problems, the technical solution of the present invention comprises the following steps:

[0006] S1. The recessive nuclear sterile rice material is used as the female parent, and the excellent indica restorer line, the long-grain fragrant conventional indica rice, the indica-japonica intermediate wide-compatibility restorer line, and the japonica rice are used as the male parent. According to the growth period of the recessive nuclear sterile rice material and the core parent, the sowing and transplanting period is reasonably adjusted, and mixed pollination and hybridization are carried out to obtain F1 seeds.

[0007] Furthermore, the excellent indica restorer line in step S1 is "Minghui 164" or "Fuhui 676" or "Yuehe Si Miao", the long-grain fragrant conventional indica rice is "19 Xiang" or "Nanjing Xiangzhan", the indica-japonica intermediate wide-compatibility restorer line is "Yuhe" or "Minghui 703" or "Minghui 3009", and the japonica rice is "Shennong 9903" or "Liaojing 294".

[0008] Further, the method further comprises the following steps:

[0009] S3, mixing the seeds F2 seeds obtained in step S2 in equal amounts, sowing them in areas severely affected by rice blast, conducting identification of natural conditions induction at the seedling stage, pulling out seedlings with medium or above resistance to seedling blast, and transplanting them individually in the field, while sowing and transplanting the core parent in step S1 in multiple phases, with a fixed number of days between each phase, and when they are heading and flowering, selecting sterile plants with specific traits as female parents, and the core parent in step S1 as male parents, and performing mixed pollination and hybridization to obtain BC1F1 seeds;

[0010] S4, repeat step S2 and step S3 at least twice to obtain BC3F2 seeds;

[0011] S5. The BC3F2 seeds obtained in step S4 are subjected to seedling blast pressure identification according to step S3, and seedlings with medium or above seedling blast resistance are selected and planted individually in the field. When heading and flowering, fertile plants with large and sufficient pollen quantity are marked from the population, and excellent plants with specific traits are selected from the marked fertile plants when mature. The selected excellent plants are classified into indica and japonica attribute morphology using the "program index method" to obtain BC3F3 seeds.

[0012] Further, the method further comprises the following steps:

[0013] S6, sowing the BC3F3 seeds selected in step S5 according to strains, planting 48 plants per strain, performing single plant selection according to step S5, and harvesting BC3F4 seed strains that meet the breeding goals;

[0014] S7, sowing the BC3F4 seeds selected in step S6 according to strains, planting 48 plants per strain, and at the same time conducting natural condition induction identification during the whole growth period in the rice blast disaster area, and selecting representative high-quality single plant pollen from each strain when heading and flowering, and conducting test crosses with the indica three-line sterile line and indica rice test varieties to obtain the corresponding test cross first generation and test cross male parent BC3F5 seed strains;

[0015] S8. The test cross generation obtained in S7 and the test cross male parent BC3F5 seed strain are sown and planted adjacent to each other, and a BC3F6 strain with good affinity to the indica rice test variety F1 test cross with a fruit set rate of more than 75%, strong hybrid vigor in the test cross generation, and good comprehensive traits is selected.

[0016] Furthermore, the BC3F6 strain in step S8 is grown to the 10th generation, and then the "program index method" is used to identify the indica and japonica properties to obtain a japonica-type restorer line with good plant and leaf morphology, moderate growth period, strong lodging resistance, sufficient pollen quantity, broad affinity, strong resilience, and good combining ability.

[0017] Furthermore, the recessive nuclear sterile material of rice in step S1 is the "Sanming recessive nuclear sterile material" with broad affinity.

[0018] Further, the method further comprises the following steps:

[0019] S2. Planting the seeds F1 obtained in step S1, selecting individual plants with excellent agronomic traits, strong advantages, and a fruit setting rate of ≥70% at maturity, harvesting a certain number of seeds from each individual plant, and obtaining F2 seeds.

[0020] Furthermore, the multiple phases in step S3 are 3 phases, each phase is 7 days apart, and the specific traits are plant type tending to be japonica, ear type tending to be japonica, grain type tending to be indica, moderate growth period, and hard stalks and resistance to lodging.

[0021] Furthermore, the indica three-line sterile line used is "Mingyuan A", and the indica rice test variety is "Nanjing 11".

[0022] The advantages of the present invention compared with the prior art are:

[0023] 1. The present invention provides a method for creating a japonica-biased restorer line by utilizing recessive nuclear sterility of rice. The japonica-biased restorer line has wide affinity and can bear fruit normally and have a strong yield advantage when paired with most indica-type sterile lines, thus overcoming the problem of hybridization reproductive barriers between indica and japonica subspecies and solving the problem of narrow sources of indica-type sterile lines.

[0024] 2. The present invention provides a method for creating a japonica-biased restorer line by utilizing recessive nuclear sterility of rice. The prepared hybrid rice combination between indica and japonica subspecies has longer panicles and lower grain density, thus solving the problem of serious rice false smut in the indica-japonica hybrid combination.

[0025] 3. The present invention provides a method for creating a japonica-biased restorer line by utilizing recessive nuclear sterility of rice, which solves the problem of low seed yield and high seed cost in hybrid rice combination production between indica and japonica subspecies, and improves the economic benefits of seed producers. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of a breeding method for creating a japonica-type restorer line by utilizing recessive nuclear sterility of rice.

[0027] Figure 2This is a single plant photo of the indica-japonica hybrid restorer line "Minghui 3310" in Example 1 of the method for creating a japonica-biased restorer line by utilizing recessive nuclear sterility of rice of the present invention.

[0028] Figure 3 This is a single plant photo of the indica-japonica hybrid restorer line "Minghui 3308" in Example 2 of the method for creating a japonica-biased restorer line by utilizing recessive nuclear sterility of rice of the present invention.

[0029] Figure 4 A comparison diagram of individual plants, panicles and spikelets of the wild type and mutant types of "Sanming recessive nuclear sterile material" in a method for creating a japonica-type restorer line by utilizing recessive nuclear sterility of rice in the present invention. DETAILED DESCRIPTION

[0030] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the appended claims.

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] A method for creating a japonica-type restorer line by utilizing recessive nuclear sterility of rice comprises the following steps:

[0033] S1. Using recessive nuclear male sterile rice materials as female parents, using excellent indica restorer lines, long-grain fragrant conventional indica rice, indica-japonica intermediate wide-compatibility restorer lines, and japonica rice as core parents as male parents, reasonably adjusting the sowing and transplanting period according to the growth period of recessive nuclear male sterile rice materials and core parents, and performing mixed pollination and hybridization to obtain F1 seeds;

[0034] S2, planting the seeds F1 obtained in step S1, selecting individual plants with excellent agronomic traits, strong advantages, and a fruiting rate of ≥70% at maturity, harvesting a certain number of seeds from each individual plant, and obtaining F2 seeds;

[0035] S3, after mixing equal amounts of the seeds F2 seeds obtained in step S2, sowing them in the areas severely affected by rice blast, conducting identification of natural conditions induction at the seedling stage, pulling out the seedlings with medium or above resistance to seedling blast, and transplanting them individually in the field, and at the same time sowing and transplanting the core parent in step S1 in multiple phases, with a fixed number of days between each phase, and when they are heading and flowering, selecting the sterile plants with specific traits as the female parent, and the core parent in step S1 as the male parent, and performing mixed pollination and hybridization to obtain BC1F1 seeds;

[0036] S4, repeat step S2 and step S3 at least twice to obtain BC3F2 seeds;

[0037] S5, the BC3F2 seeds obtained in step S4 are subjected to rice blast seedling pressure identification according to step S3, and the seedlings with a medium or above resistance level to seedling blast are selected, and a single seedling is planted in the field, and when heading and flowering, fertile plants with large and sufficient pollen quantity are marked from the population, and when mature, excellent plants with specific traits are selected from the marked fertile plants, and the selected excellent plants are classified by indica and japonica attributes and morphology using the "program index method" to obtain BC3F3 seeds;

[0038] S6, sowing the BC3F3 seeds selected in step S5 according to strains, planting 48 plants per strain, performing single plant selection according to step S5, and harvesting BC3F4 seed strains that meet the breeding goals;

[0039] S7, sowing the BC3F4 seeds selected in step S6 according to strains, planting 48 plants per strain, and at the same time conducting natural condition induction identification during the whole growth period in the rice blast disaster area, and selecting representative high-quality single plant pollen from each strain when heading and flowering, and conducting test crosses with the indica three-line sterile line and indica rice test varieties to obtain the corresponding test cross first generation and test cross male parent BC3F5 seed strains;

[0040] S8, sowing and planting the test cross F1 obtained in S7 and the test cross male parent BC3F5 seed strain adjacent to each other, selecting the BC3F6 strain with good affinity to the indica rice test F1 with a fruit setting rate of more than 75%, strong hybrid vigor in the test cross F1, and good comprehensive traits,

[0041] Furthermore, the recessive nuclear sterile material of rice in step S1 is the "Sanming recessive nuclear sterile material" with broad affinity.

[0042] Furthermore, in step S1, the excellent indica restorer line is "Minghui 164" or "Fuhui 676" or "Yuehe Si Miao", the long-grain fragrant conventional indica rice is "19 Xiang" or "Nanjing Xiangzhan", the intermediate indica-japonica wide-compatibility restorer line is "Yuhe" or "Minghui 703" or "Minghui 3009", and the japonica rice is "Shennong 9903" or "Liaojing 294".

[0043] Furthermore, the multiple phases in step S3 are 3 phases, each phase is 7 days apart, and the specific traits are plant type tending to be japonica, ear type tending to be japonica, grain type tending to be indica, moderate growth period and hard stalks and resistance to lodging.

[0044] Furthermore, the three-line sterile line of indica rice "Mingyuan A" and the indica rice test variety "Nanjing 11" were used.

[0045] Furthermore, the BC3F6 strain in step S8 was grown to the 10th generation, and then the "program index method" was used to identify the indica and japonica properties, to obtain a japonica-type restorer line with good plant and leaf morphology, moderate growth period, strong lodging resistance, sufficient pollen quantity, broad affinity, strong resilience, and good combining ability.

[0046] Embodiment 1

[0047] (1) The recessive genic male sterile material with wide compatibility of Sanming was used as the female parent, and the core parents such as the excellent indica restorer lines "Minghui 164, Yuehe Si Miao", the long-grain fragrant conventional indica rice "19 Xiang, Nanjing Xiangzhan", the intermediate indica-japonica wide compatibility restorer lines "Yuhe, Minghui 703", and the japonica rice "Shennong 9903, Liaojing 294" were used as the male parents. According to the growth period of the recessive genic male sterile material of rice and the core parents, the sowing and transplanting period was reasonably adjusted, and mixed pollination and hybridization were carried out to obtain F1 seeds.

[0048] (2) Plant 503 F1 seeds, select 203 individual plants with excellent agronomic traits, strong advantages, and a fruit setting rate of ≥ 70% at maturity, and collect 500 seeds from each individual plant to obtain F2 seeds.

[0049] (3) After the F2 seeds were mixed in equal amounts, 2 kg of seeds were sown in the rice blast disaster area, and the natural conditions induction identification was carried out at the seedling stage. 5163 seedlings with a resistance level of medium or above were pulled out and planted in the field. At the same time, 100 plants of each core parent in step (1) were sown and planted in three phases, with an interval of 7 days between each phase. When they were heading and flowering, 59 sterile plants with a plant type that was more japonica, a panicle type that was more japonica, a grain type that was more indica, a moderate growth period, and a hard stalk that was resistant to lodging were selected as the female parent, and the core parent in step (1) was selected as the male parent for mixed pollination and hybridization to obtain BC1F1 seeds.

[0050] (4) BC3 repeated steps (2) and (3) twice to obtain 2 kg of F2 seeds.

[0051] (5) 2 kg of BC3F2 seeds were used to identify the rice blast stress at the seedling stage according to step (3). 6,162 seedlings with a medium or above resistance level to seedling blast were selected and planted in the field. When heading and flowering, 211 fertile plants with large and sufficient pollen were marked from the population. When mature, excellent plants with japonica-like plant type, japonica-like panicle type, indica-like grain type, moderate growth period, hard stalks and resistance to lodging were selected from the marked fertile plants. The "program index method" was used to classify the selected excellent plants into indica-japonica attributes and morphology, and 58 japonica-like BC3F3 excellent individual seeds were obtained.

[0052] (6) The selected BC3F3 seeds were sown by strain, with 48 plants planted per strain, and individual plants were selected according to step (5), and 55 BC3F4 seed strains that met the breeding goals were harvested.

[0053] (7) The selected BC3F4 seeds were sown according to the strains, with 48 plants planted per strain. At the same time, natural conditions were induced and identified during the whole growth period in the areas severely affected by rice blast. When the seeds were heading and flowering, representative and excellent single pollen from each strain was selected and test-crossed with the three-line sterile indica rice line "Mingyuan A" and the indica rice test variety "Nanjing 11" to obtain the corresponding test-cross first generation and test-cross male parent BC3F5 seed strains.

[0054] (8) The obtained test cross F1 and test cross male parent BC3F5 seed lines were sown and planted adjacently, and 23 BC3F6 lines with good affinity with the indica rice test F1 with a fruit set rate of more than 75%, strong heterosis in the test cross F1, and good comprehensive traits were selected. Finally, after 10 generations, the "program index method" was used to identify the indica and japonica properties, and the 11th line was obtained, which was the japonica-biased restorer line "Minghui 3310" with good plant and leaf morphology, moderate growth period, strong lodging resistance, sufficient pollen, wide affinity, strong resilience, and good combining ability.

[0055] The bred Minghui 3310 has good affinity. When hybridized with Nanjing 11, the F1 fruit set rate reached 88.3%. It has generally strong combining ability. The indica-japonica inter-subspecies hybrid rice combination "Mingyuanyou 3310" mated with Mingyuan A has an average yield per mu that is 8% higher than the control variety Yiyou 673, reduces the cost of pesticide application by 70 yuan, and the seed production yield per mu reaches more than 230kg.

[0056] Embodiment 2

[0057] (1) The recessive genic male sterile material with wide compatibility in Sanming was used as the female parent, and the core parents such as the excellent indica restorer lines "Fuhui 676, Yuehe Si Miao", the fragrant long-grain conventional indica rice "19 Xiang, Nanjing Xiangzhan", the intermediate indica-japonica wide compatibility restorer lines "Yuhe, Minghui 3009", and the japonica rice "Shennong 9903, Liaojing 294" were used as the male parents. According to the growth period of the recessive genic male sterile material and the core parents, the sowing and transplanting period was reasonably adjusted, and mixed pollination and hybridization were carried out to obtain F1 seeds.

[0058] (2) 603 F1 seeds were planted, and 218 individual plants with excellent agronomic traits, strong advantages, and a fruit setting rate of ≥70% were selected at maturity. 500 seeds were collected from each individual plant to obtain F2 seeds.

[0059] (3) After the F2 seeds are mixed in equal amounts, 2 kg of seeds are sown in the rice blast-stricken areas, and the natural conditions induction identification is carried out at the seedling stage. 5382 seedlings with a resistance level of medium or above to seedling blast are pulled out and planted in the field individually. At the same time, 100 plants of each core parent in step (1) are sown and planted in three phases, with an interval of 7 days between each phase. When they are heading and flowering, 52 sterile plants with a plant type that is more japonica, a panicle type that is more japonica, a grain type that is more indica, a moderate growth period, and a hard stalk that is resistant to lodging are selected as female parents, and the core parent in step (1) is the male parent, and mixed pollination and hybridization are carried out to obtain BC1F1 seeds.

[0060] (4) Repeat steps (2) and (3) twice to obtain 2 kg of BC3F2 seeds.

[0061] (5) 2 kg of BC3F2 seeds were used for seedling blight pressure identification according to step (3), and 5161 seedlings with a seedling blight resistance level of medium or above were selected and planted in the field. When heading and flowering, 193 fertile plants with large and sufficient pollen were marked from the population. When mature, excellent plants with japonica-like plant type, japonica-like panicle type, indica-like grain type, moderate growth period, and hard stalks were selected from the marked fertile plants. The "program index method" was used to classify the selected excellent plants into indica-japonica attributes and morphology, and 55 BC3F3 excellent individual seeds were obtained.

[0062] (6) The selected BC3F3 seeds were sown according to strains, with 48 plants planted in each strain. Individual plants were selected according to step (5), and 48 BC3F4 seed strains that met the breeding goals were harvested.

[0063] (7) The selected BC3F4 seeds were sown according to the strains, with 45 plants planted per strain. At the same time, natural conditions were induced and identified during the whole growth period in the areas severely affected by rice blast. When the seeds were heading and flowering, representative and excellent single pollen from each strain was selected and test-crossed with the three-line sterile indica rice line "Mingyuan A" and the indica rice test variety "Nanjing 11" to obtain the corresponding test-cross first generation and test-cross male parent BC3F5 seed strains.

[0064] (8) The obtained test cross first generation and test cross male parent BC3F5 seed lines were sown and planted adjacent to each other, and 21 BC3F6 lines with good affinity with the indica rice test variety F1 with a fruit set rate of more than 75%, strong hybrid vigor in the test cross first generation, and good comprehensive traits were selected. After further generation to 10, the "program index method" was used to identify the indica and japonica properties. Line No. 08 was obtained, which was a japonica-type restorer line "Minghui 3308" with good plant and leaf morphology, moderate growth period, strong lodging resistance, sufficient pollen amount, wide affinity, strong resilience, and good combining ability.

[0065] The bred "Minghui 3308" has good affinity. When hybridized with Nanjing 11, the F1 fruit set rate reached 89.3%. It has generally strong combining ability. The indica-japonica inter-subspecies hybrid rice combination "Mingyuanyou 3308" matched with Mingyuan A has an average yield per mu that is 8.5% higher than the control variety Yiyou 673, reduces the cost of pesticide application by 70 yuan, and the seed production yield per mu reaches more than 220kg.

[0066] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0067] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0068] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A method for creating a japonica-type restorer line using recessive nuclear sterility of rice, characterized in that: The following steps are involved: S1. The recessive nuclear sterile rice material is used as the female parent, and the excellent indica restorer line, the long-grain fragrant conventional indica rice, the indica-japonica intermediate wide-compatibility restorer line, and the japonica rice are used as the male parent. According to the growth period of the recessive nuclear sterile rice material and the core parent, the sowing and transplanting period is reasonably adjusted, and mixed pollination and hybridization are carried out to obtain F1 seeds.

2. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 1, characterized in that: The rice recessive nuclear sterile material in step S1 is the "Sanming recessive nuclear sterile material" with broad affinity.

3. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 2, characterized in that: In the step S1, the high-quality indica restorer line is "Minghui 164" or "Fuhui 676" or "Yuehe Si Miao", the long-grain fragrant conventional indica rice is "19 Xiang" or "Nanjing Xiangzhan", the intermediate indica-japonica wide-compatibility restorer line is "Yuhe" or "Minghui 703" or "Minghui 3009", and the japonica rice is "Shennong 9903" or "Liaojing 294".

4. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 1, characterized in that: The following steps are also included: S2. Planting the seeds F1 obtained in step S1, selecting individual plants with excellent agronomic traits, strong advantages, and a fruit setting rate of ≥70% at maturity, harvesting a certain number of seeds from each individual plant, and obtaining F2 seeds.

5. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 4, characterized in that: The following steps are also included: S3, mixing the seeds F1 seeds obtained in step S2 in equal amounts, sowing them in areas severely affected by rice blast, conducting identification of natural conditions induction at the seedling stage, pulling out seedlings with medium or above resistance to seedling blast, and transplanting them individually in the field, while sowing and transplanting the core parent in step S1 in multiple phases, with a fixed number of days between each phase, and when they are heading and flowering, selecting sterile plants with specific traits as female parents, and the core parent in step S1 as male parents, and performing mixed pollination and hybridization to obtain BC1F1 seeds; S4, repeat step S2 and step S3 at least twice to obtain BC3F2 seeds; S5. The BC3F2 seeds obtained in step S4 are subjected to seedling blast stress identification according to step S3, and seedlings with a medium or above seedling blast resistance level are selected and planted individually in the field. When heading and flowering, fertile plants with large and sufficient pollen quantity are marked from the population, and excellent plants with specific traits are selected from the marked fertile plants when mature. The selected excellent plants are classified by indica and japonica attributes and morphology using the "program index method" to obtain BC3F3 seeds.

6. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 5, characterized in that: The multiple phases in step S3 are 3 phases, each phase is separated by 7 days, and the specific traits are that the plant type is more japonica, the ear type is more japonica, the grain type is more indica, the growth period is moderate, and the stalk is hard and resistant to lodging.

7. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 5, characterized in that: The following steps are also included: S6, sowing the BC3F3 seeds selected in step S5 according to strains, planting 48 plants per strain, performing single plant selection according to step S5, and harvesting BC3F4 seed strains that meet the breeding goals; S7, sowing the BC3F4 seeds selected in step S6 according to strains, planting 48 plants per strain, and at the same time conducting natural condition induction identification during the whole growth period in the rice blast disaster area, and selecting representative high-quality single plant pollen from each strain when heading and flowering, and conducting test crosses with the indica three-line sterile line and indica rice test varieties to obtain the corresponding test cross first generation and test cross male parent BC3F5 seed strains; S8. The test cross generation obtained in S7 and the test cross male parent BC3F5 seed strain are sown and planted adjacent to each other, and a BC3F6 strain with good affinity to the indica rice test variety F1 test cross with a fruit set rate of more than 75%, strong hybrid vigor in the test cross generation, and good comprehensive traits is selected.

8. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 7, characterized in that: The indica three-line sterile line used is "Mingyuan A", and the indica rice test variety is "Nanjing 11".

9. The method for creating a japonica-type restorer line using recessive nuclear sterility of rice according to claim 7, characterized in that: The BC3F6 strain in step S8 is grown to the 10th generation, and then the "program index method" is used to identify the indica and japonica properties to obtain a japonica-type restorer line with good plant and leaf morphology, moderate growth period, strong lodging resistance, sufficient pollen volume, wide affinity, strong resilience, and good combining ability.

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