CN115380816A

CN115380816A - Method for creating sorghum maintainer line

Info

Publication number: CN115380816A
Application number: CN202211027969.9A
Authority: CN
Inventors: 殷勇; 张�林; 周俊辉; 刘兴贵; 应恒; 张德银
Original assignee: Yibin Academy Of Agricultural Sciences
Current assignee: Yibin Academy Of Agricultural Sciences
Priority date: 2022-08-25
Filing date: 2022-08-25
Publication date: 2022-11-25
Anticipated expiration: 2042-08-25
Also published as: CN115380816B

Abstract

The invention provides a method for creating a sorghum maintainer line, which relates to the technical field of crop breeding and comprises the following steps: and (3) carrying out top crossing by using the sorghum maintainer line as a female parent and using the sorghum hybrid as a male parent to obtain an F1 generation, carrying out selfing on the F1 generation to obtain an F2 generation, and simultaneously carrying out test crossing on the F1 generation by using the sorghum sterile line as a female parent to obtain a test cross. And (4) screening out the individual plants with the retention capacity in the F2 generation according to whether the test cross strains have the total sterile plants. Then carrying out selfing purification and backcross transformation on the single plants with the maintenance capacity to obtain sterile lines, and carrying out fertility identification in the whole process to finally obtain the sorghum maintenance line and the corresponding sterile line. The method can solve the technical problems of low success rate, complex operation and long time consumption of the existing manual insurance creation maintenance system.

Description

Method for creating sorghum maintainer line

Technical Field

The invention relates to the technical field of crop breeding, and particularly discloses a method for creating a sorghum maintainer line.

Background

Manual production of maintainers is a method for creating maintainers, and is written in "general theory of crop breeding" p174-p175. The technical route is as follows: the sterile plants found in the field or obtained by artificial mutagenesis are used for artificial preparation and preservation through hybridization, top crossing, selfing and test crossing. It is envisaged that the introduction of a sterile nuclear gene into a fertile cytoplasm to produce a maintainer line of N (rr) genotype would include the steps of crossing for the purpose of introducing a dominant fertile gene R into the sterile plant to restore fertility to the hybrid, top crossing for the purpose of introducing a hybrid recessive sterile gene R into the fertile cytoplasm, and selfing for the purpose of separating and homozygous the heterozygous recessive sterile gene in the fertile cytoplasm into fertile N (rr), and test crossing for the purpose of distinguishing fertile N (rr) from other fertile phenotypes.

Then, the maintainer line is created by using the existing manual maintainer line method, 5 steps of hybridization, top cross, selfing, test cross, identification and the like are needed to detect the maintainer line N (rr), the theoretical success rate is 1/8, and the defects of complex operation, long time consumption, low efficiency and the like exist.

Disclosure of Invention

The invention aims to provide a method for creating a sorghum maintainer line, which can solve the problems of complex operation, long time consumption, low efficiency and the like of creating the sorghum maintainer line by the conventional manual maintenance method.

The invention is realized by the following technical scheme:

the invention provides a method for creating a sorghum maintainer line, which comprises the following steps: carrying out top crossing by taking a sorghum maintainer line as a female parent and a sorghum hybrid as a male parent to obtain an F1 generation, selfing the F1 generation to obtain an F2 generation, carrying out test crossing by taking the sorghum sterile line as the female parent and the F1 generation to obtain a test cross, and when a full sterile plant appears in the test cross, selecting the single plant with the maintaining capacity in the F2 generation, and continuously selfing and purifying to obtain the sorghum maintainer line and a corresponding sterile line. Compared with the prior art, the invention at least has the following advantages and positive effects:

1. the invention can identify the maintainer line only by 3 generations, 2 generations ahead of the manual maintainer making method, and shortens the breeding time by 1 year.

2. The invention identifies the test cross species, theoretically 1/2 of the test cross species is the full sterile plant, 4 times of the manual maintenance method, and greatly improves the success rate of creating the maintenance line.

3. The invention takes the maintainer line and the hybrid as parents, and both parents have more excellent genes, thus being beneficial to screening out the maintainer line with excellent agronomic characters.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram of a manufacturing process of a conventional manufacturing method of the present invention;

fig. 2 is a schematic diagram of a manufacturing process of a method for creating a sorghum maintainer line provided by the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to specific examples.

The invention specifically provides a method for creating a sorghum maintainer line, which comprises the following steps: carrying out top crossing by taking a sorghum maintainer line as a female parent and a sorghum hybrid as a male parent to obtain an F1 generation, selfing the F1 generation to obtain an F2 generation, carrying out test crossing by taking a sorghum sterile line as a female parent and the F1 generation to obtain a test cross, and when a full sterile plant appears in the test cross, selecting a single plant with the maintaining capacity in the F2 generation, selfing and purifying the single plant with the maintaining capacity in the F2 generation to obtain the sorghum maintainer line. The method can screen and obtain the maintainer line by carrying out top crossing, test crossing and identification, and compared with the traditional manufacturing and protection method, the method has simpler operation and shorter time consumption, greatly reduces the operation difficulty of operators and shortens the manufacturing and protection time; and the success rate of the test cross identification of the method is 1/2, and compared with 1/8 of the success rate of the traditional method, the success rate is greatly improved.

The genotype of the sorghum of the maintainer line is N (Rr), the genotype of the sorghum of the hybrid is S (Rr), and the genotype of the sorghum of the sterile line is S (Rr). Wherein the maintainer line is a plant line which can keep the sterile line male sterile when used as a male parent to be crossed with the sterile line; the hybrid is the offspring produced by the hybridization of the sterile line as the female parent and the recovery line as the male parent; the sterile line is a line which is formed by hybridizing the selected male sterile individual plant with a fertile individual and then carrying out continuous backcross cultivation and has male sterility characteristics and uniformity.

The screening comprises the following steps: and pollinating the sterile line of the sorghum by using the sorghum in the F1 generation, when fertile plants appear in the test cross seeds, the genotype of the sorghum in the F1 generation is N (Rr) and is eliminated, and when the test cross seeds are all sterile plants, the genotype of the sorghum in the F1 generation is N (Rr) and is reserved.

The screening step further comprises a selfing purification step, and the selfing purification step comprises the following steps: and (3) continuously selfing and purifying waxy strains with the plant height of less than or equal to 110cm, the ear length of more than or equal to 25cm and high leaf disease resistance in the F2 generation selected progeny for multiple times. Wherein, the plant height is less than or equal to 110cm, the ear length is more than or equal to 25cm, the plant is highly resistant to leaf diseases, and the waxy materials are all excellent agronomic characters, and besides selecting the strains with excellent agronomic characters, the strains with similar agronomic characters are selected to ensure that the agronomic characters of the parents can be stably inherited. In addition, the genotype of the F2 generation is highly heterozygous, and the character is unstable, so that a stable line with homozygous alleles and uniform character can be obtained only by selfing for multiple generations, wherein the waxy quality is that the amylopectin in grains accounts for more than 95% of the total starch amount.

The selfing purification also comprises a backcross transformation step, and the backcross transformation comprises the following steps: and (3) backcrossing the sterile line with F2 generation which has the plant height less than or equal to 110cm, the ear length more than or equal to 25cm, high leaf disease resistance and waxy and has the retention capacity to obtain the corresponding sterile plant. The genetic characteristics of the sterile line and the maintainer line are that the nuclear genes are completely the same, and the cytoplasmic genes are different; the main character difference is that the sterile line has no pollen, the maintainer line has pollen, and other characters are basically consistent. Therefore, the sterile plants which have similar agronomic characters with the maintainer line and are highly sterile are selected to be backcrossed with the maintainer line, so that the sterile line can be quickly obtained, and the transformation efficiency is improved.

The selection of the sterile plant comprises the following steps: observing whether the sterile plant has pollen or not, and using the sterile plant without pollen for backcross transformation. Since the sterility of backcross progeny is influenced by some other micro-effect genes besides N (rr), continuous selfing is needed to promote the purification of other micro-effect genes, and the sterility of the sterile line is identified through transformation, thereby improving the retention of the maintainer line. The sorghum maintainer line preferably comprises 9B.

The sorghum maintainer line preferably comprises 9B.

Examples

9B breeding: in 2013, hybrid seeds were prepared in Sichuan by using the maintainer line IS10362B introduced from Chinese as the female parent and Lunuo No. 8 as the male parent. In 2013, in Yunnan, false hybrid plants and poor single plants are removed, other plants are bagged for selfing, endosperm waxy property identification is carried out on selfed seeds, and waxy seeds are screened and reserved. In 2014, in Sichuan, a single plant with the plant height lower than 1.1 m and excellent other agronomic characters is selected for test crossing with 45A. In 2014, in Yunnan, inbred seeds and test cross seeds are planted in pairs, fertility identification is carried out on the test cross seeds, semi-sterile and fertile ear rows are eliminated, and 1-3 excellent single plants are selected from the full sterile ear rows to continue backcrossing. And (5) continuing fertility identification in two places of Sichuan and Hainan in 2015, and carrying out backcross in a preferred mode. In 2016, a sterile line with excellent comprehensive character, stable heredity and high male sterility degree and its corresponding maintainer line are formed in Sichuan, and are named as 9A and 9B.

(see FIG. 2):

step 1, planting a sorghum maintainer line and a hybrid sorghum.

Step 2, in the flowering phase, the maintainer line is manually castrated to serve as a female parent, the hybrid sorghum serves as a male parent, and hybrid seeds F1 are prepared, wherein the number of the hybrid seeds is preferably more than or equal to 800.

And 3, planting the sorghum sterile line and the hybrid F1.

And 4, screening single plants with excellent agronomic characters from the hybrid population during the flowering phase, testing and crossing with the sterile line, and performing selfing F2.

And 5, planting the F2 and the corresponding test cross hybrid in pairs for 1 line.

And 6, during the flowering phase, identifying the anther fertility of the test cross. Eliminating fertile and semi-sterile ear rows, retaining full sterile ear rows, and continuously transferring sterile lines.

And 7, screening dominant individual plants from the panicle rows with excellent agronomic characters on the basis of the step 6, and backcrossing to transform the sterile lines.

And (5) operating according to the step 7 until a stable maintainer line and a sterile line are formed.

Comparative example

Referring to FIG. 1, sterile plants are first used as female parents, fertile varieties N (RR) are used as male parents for hybridization to obtain hybrid lines S (Rr), fertile varieties are then selected as female parents and the obtained hybrid lines are used for top crossing to obtain 1/2N (RR) and 1/2N (Rr), selfing is further carried out to obtain 1/2S (Rr), 1/8S (RR) and 1/8S (RR), and meanwhile, sterile lines are used as female parents for test crossing, wherein only 1/8S (RR) is the result obtained by N (RR) test crossing, so the success rate is 1/8 and is far lower than 1/2 of the invention, and the method provided by the invention uses 1 and 2 steps more than the method provided by the invention, the time consumption is longer, and the operation is more complicated.

In summary, the following steps:

the invention provides a method for creating a sorghum maintainer line, which can screen and obtain the sorghum maintainer line through top crossing, test crossing and identification, and compared with the traditional manual sorghum maintainer line, the method has the advantages of simpler operation and shorter time consumption, greatly reduces the operation difficulty of operators, and shortens the sorghum maintainer line manufacturing and maintaining time; and the success rate of the method identified by test cross is 1/2, and compared with the traditional 1/8, the success rate is greatly improved.

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. A method of creating a sorghum maintainer line comprising the steps of: carrying out top crossing by taking a sorghum maintainer line as a female parent and a sorghum hybrid as a male parent to obtain an F1 generation, selfing the F1 generation to obtain an F2 generation, carrying out test crossing by taking a sorghum sterile line as a female parent and the F1 generation to obtain a test cross, and when a full sterile plant appears in the test cross, selecting a single plant with the maintaining capacity in the F2 generation, and selfing and purifying the single plant with the maintaining capacity in the F2 generation to obtain the sorghum maintainer line.

2. The method for creating a sorghum maintainer line as claimed in claim 1, wherein the genotype of the sorghum maintainer line is N (Rr), the genotype of the sorghum hybrid is S (Rr), and the genotype of the sorghum sterile line is S (Rr).

3. A method of creating a sorghum maintainer according to claim 2, wherein the screening comprises the steps of: pollinating the sorghum sterile line by using the sorghum in the F1 generation, when the test cross seeds have fertile plants, the genotype of the sorghum in the F1 generation is N (Rr) and is eliminated, and when the test cross seeds are all sterile plants, the genotype of the sorghum in the F1 generation is N (Rr) and is reserved.

4. The method of creating a sorghum maintainer line according to claim 1, further comprising a step of selfing purification after the screening step, the selfing purification comprising the steps of: continuously selfing a glutinous strain with a plant height of less than or equal to 110cm and a spike length of more than or equal to 25cm and high leaf disease resistance in the F2 generation selected offspring; the selfing purification was repeated multiple times.

5. The method for creating a sorghum maintainer line according to claim 1, further comprising a step of backcross transformation after the purification by selfing, wherein the backcross transformation comprises the following steps: and (3) selecting the sterile line to be backcrossed with the F2 generation which has the plant height of less than or equal to 110cm, the ear length of more than or equal to 25cm, high leaf disease resistance and waxy and has the retention capacity to obtain a corresponding sterile plant.

6. The method for creating a sorghum maintainer line according to claim 5, wherein the selection of the sterile plant comprises the steps of: observing whether the sterile plant has pollen or not, and using the sterile plant without pollen for backcross transformation.

7. A method of creating a sorghum maintainer according to any one of claims 1 to 6, wherein the sorghum maintainer comprises kava 9B.