Method for identifying advantages of new hybrid japonica rice combination

Abstract

The embodiment of the invention discloses a method for identifying the advantages of a new hybrid japonica rice combination. The method comprises the following steps: selecting a restorer population; analyzing the combining ability of the restoring line; creating a high combining ability dominant genic male sterility restoring line group material; a restoring line group (stamen abortion) containing dominant genic male sterility genes is used as a female parent, a maintainer line material selected according to a target is used as a male parent, and the advantages of a sterile line to be transfected are predicted; performing advantage identification on the newly assembled combination; and determining a breeding direction and a sterile line transformation material. According to the creation method of the dominant genic male sterile male parent group of the hybrid japonica rice, the difficulty of hybrid japonica rice combination advantage identification can be reduced, the number of new combination identification can be increased, the hereditary characteristics of maintainer line materials can be determined in the early stage, and the breeding target can be clarified, which is of great significance to the breeding work of the hybrid japonica rice.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of genetic breeding, and in particular to a method for identifying the advantages of new combinations of hybrid japonica rice. Background Art

[0002] There are many technical difficulties in the process of hybrid japonica rice breeding, among which the long breeding cycle of new combinations and unclear breeding targets of maintainer lines have restricted the development of hybrid japonica rice. Since the discovery of nuclear dominant sterility in indica rice, it has not been applied in japonica rice. Creating a group of restorer lines containing nuclear dominant sterility and performing high-throughput matching on high-generation stable maintainer lines of hybrid japonica rice can greatly reduce working time, improve work efficiency, and reduce the probability of matching failure. At the same time, matching the maintainer line with the restorer line group of nuclear dominant sterility, and analyzing the combining ability of plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, rice quality, and yield can determine the key materials for breeding sterile lines and clarify the breeding direction of future hybrid combinations. Summary of the invention

[0003] To this end, the embodiment of the present invention provides a method for identifying the advantages of new combinations of hybrid japonica rice. The present invention creates a batch of restorer line materials containing nuclear dominant sterility and good combining ability, clarifies that the restorer line population with nuclear dominant sterility is used as the female parent, and is paired with the maintainer line, and the plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, rice quality, and yield are analyzed for combining ability, thereby identifying the advantages of new combinations of hybrid japonica rice. This method can shorten the time for traditional new combination advantage identification by 2-3 years, and make the breeding of the maintainer line more targeted.

[0004] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0005] A method for identifying the superiority of a new japonica hybrid rice combination, the method comprising:

[0006] (1) japonica rice materials with moderate plant height and containing restoration genes were listed as parent populations;

[0007] (2) Select japonica rice materials with good adaptability to the local environment and large panicles from the parent population as the restorer line population;

[0008] (3) The restorer line population and the sterile line material are matched according to the NCⅡ incomplete hybridization method, the combining ability of the male parent is determined, and the male parent with good heritability is selected;

[0009] (4) Backcrossing the male parent with good heritability with the dominant nuclear sterile material to obtain a restorer line population containing the dominant nuclear sterile gene;

[0010] (5) using a restorer line population containing a dominant nuclear sterile gene as the female parent and mating it with a maintainer line material selected according to the target as the male parent;

[0011] (6) Identify the advantages of the hybrid combinations, analyze the heritability of the maintainer materials, and analyze the composition of heterosis;

[0012] (7) Determine the superior hybrid combination as the key target for the next step of breeding and the maintenance material for converting the sterile line.

[0013] Furthermore, the restorer line population is selected from japonica rice materials with moderate plant height, good adaptability to the local environment, and large panicles containing the restorer gene.

[0014] Furthermore, in step (3), the heritability includes plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, rice quality, and yield.

[0015] Furthermore, in step (4), after 6 generations of backcrossing, the proportion of materials with aborted stamens and normal pistils in the offspring materials of the restorer line population containing the dominant nuclear sterile gene was close to 50%.

[0016] Furthermore, in step (6), the heritability includes plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, rice quality, and yield.

[0017] The embodiments of the present invention have the following advantages:

[0018] The present invention aims to solve the problem that the identification of the advantages of new combinations of hybrid japonica rice is difficult in the early stage and has a long technical cycle after the sterile line is transformed into a breeding line. During the sterile line breeding process, the sterile line breeding materials are clarified, the compatibility of a large number of maintenance line materials can be identified, high-quality maintenance line materials can be screened, the sterile line breeding quality can be improved, and the breeding efficiency of new combinations of superior hybrid japonica rice can be improved. DETAILED DESCRIPTION

[0019] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The present invention provides a method for identifying the superiority of a new combination of hybrid japonica rice, comprising the following steps:

[0021] (1) japonica rice materials with moderate plant height and containing restoration genes were listed as parent populations;

[0022] (2) Select japonica rice materials with good adaptability to the local environment and large panicles from step 1 as the restorer line population;

[0023] (3) The restorer line population and the sterile line materials were matched according to the NCⅡ incomplete hybridization method, and the combining ability of the male parent was determined. The heritability of the male parent in plant height, ear length, number of grains per ear, seed setting rate, number of effective ears, rice quality, and yield was listed;

[0024] (4) Based on the analysis results of step 3, select the genetically favorable male parent and the dominant nuclear sterile material for backcrossing for 6 generations to create a restorer line population containing the dominant nuclear sterile gene, and the proportion of the offspring materials of this population with aborted stamens and normal pistils is close to 50%;

[0025] (5) Using a restorer line population (stamen abortion) containing a dominant nuclear sterile gene as the female parent and mating it with a maintainer line material selected according to the target as the male parent;

[0026] (6) Conduct superiority identification on the hybrid combinations prepared in step 5, analyze the heritability of the maintainer materials for plant height, ear length, number of grains per ear, fruit set rate, number of effective ears, rice quality, and yield, and analyze the composition of hybrid vigor, and select maintainer materials with excellent traits for sterile line breeding.

[0027] (7) Identify the superior hybrid combination as the key target for the next step of breeding.

[0028] Example 1

[0029] In late February 2014, 35 japonica rice materials with moderate plant height and containing restoration genes were collected in Hainan. They were listed as parental groups with a standard plant height of 100-115 cm, and molecular testing was performed to find the presence of the Rf1b restoration gene.

[0030] From April to October 2014, 35 japonica rice materials with moderate plant height and containing restorer genes were collected in Shenyang for phenotypic identification, and 15 restorer line populations (ZR1-ZR15) with heading period before August 10 and more than 160 grains per panicle were selected.

[0031] In February 2015, the selected restorer line population was matched with the backbone sterile line materials Liao 5216A, Liao 99A, Liao 73A, Liao 66A, and Liao 239A in Hainan and in July-August in Shenyang according to the NC∥ incomplete hybridization method. In the spring of 2016, the 75 hybrid combinations were arranged in random blocks and repeated three times for field trials. The cultivation management was consistent with the local field. In autumn, sampling was carried out to determine the combining ability of the male parent and analyze the heritability of the male parent in terms of plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, yield, etc. The results are shown in Table 1 below.

[0032] Table 1: Results of genetic parameters of parents

[0033]

[0034] According to the test results and field performance, combined with rice quality analysis, 10 restorer materials with good combining ability were screened out, including C4, C419, C66, C768, C68, C89, R4, R157, R58, and R18.

[0035] In February 2017, 10 restorer line materials C419, C66, R4, etc. with good combining ability were hybridized with three obvious sexual nuclear sterile varieties in Hainan. From 2017 to 2020, backcrossing was carried out for six generations in Shenyang and Hainan. In the summer of 2020, BC7F1 was reached in Shenyang, and the material was stable.

[0036] In 2021, in Hainan and Shenyang, the restorer line group containing the dominant nuclear sterile gene (stamen abortion) was used as the female parent and mated with the backbone maintenance line materials Liao 66B, Liao 485B, Liao 228B, etc. as the male parent. At the same time, the sterile line corresponding to the maintenance line was used as the female parent Liao 66A, Liao 485A, Liao 228A, etc., and the restorer line corresponding to the dominant nuclear sterile restorer line group was used as the male parent for mating, and more than 30 hybrid combinations were configured. In 2022, the combination advantages of the positive and negative mating groups were compared in Shenyang. The combination advantage composition under the two mating modes was consistent, indicating that the present invention is feasible.

[0037] Since 2021, this method has been used to analyze more than 300 high-generation new maintenance line materials. Currently, 12 maintenance line materials with application value have been screened for backcrossing and breeding. In 2023, hybrid combinations of stable sterile lines such as Liao 63A bred by this method were carried out, and the prepared hybrid combinations were consistent with the predicted results.

[0038] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for identifying the superiority of new combinations of hybrid japonica rice, characterized in that: The method comprises: (1) japonica rice materials with moderate plant height and containing restoration genes were listed as parent populations; (2) Select japonica rice materials with good adaptability to the local environment and large panicles from the parent population as the restorer line population; (3) The restorer line population and the sterile line material are matched according to the NCⅡ incomplete hybridization method, the combining ability of the male parent is determined, and the male parent with good heritability is selected; (4) Backcrossing the male parent with good heritability with the dominant nuclear sterile material to obtain a restorer line population containing the dominant nuclear sterile gene; (5) using a restorer line population containing a dominant nuclear sterile gene as the female parent and mating it with a maintainer line material selected according to the target as the male parent; (6) Identify the advantages of the hybrid combinations, analyze the heritability of the maintainer materials, and analyze the composition of heterosis; (7) Determine the superior hybrid combination as the key target for the next step of breeding and the maintenance material for converting the sterile line.

2. The method for identifying the advantages of new combinations of hybrid japonica rice according to claim 1, characterized in that: The restoration line population was selected from japonica rice materials with moderate plant height, good adaptability to the local environment, and large panicles containing restoration genes.

3. The method for identifying the advantages of new combinations of hybrid japonica rice according to claim 1, characterized in that: In step (3), the heritability includes plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, rice quality, and yield.

4. The method for identifying the advantages of new combinations of hybrid japonica rice according to claim 1, characterized in that: In step (4), after 6 generations of backcrossing, the proportion of the offspring materials of the restorer line population containing the dominant nuclear sterile gene with aborted stamens and normal pistils is close to 50%.

5. The method for identifying the advantages of new combinations of hybrid japonica rice according to claim 1, characterized in that: In step (6), the heritability includes plant height, ear length, number of grains per ear, fruit setting rate, number of effective ears, rice quality, and yield.

Images