CN112219717B

CN112219717B - Method for inducing and identifying haploid generated by corn

Info

Publication number: CN112219717B
Application number: CN202011095583.2A
Authority: CN
Inventors: 范弘伟; 叶凯; 侯丽宏; 康广华
Original assignee: Jinyuan Beijing Agricultural Technology Research Institute Co ltd
Current assignee: Jinyuan Beijing Agricultural Technology Research Institute Co ltd
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2022-03-22
Anticipated expiration: 2040-10-14
Also published as: CN112219717A

Abstract

The invention discloses a method for inducing and identifying corn to produce haploid. The invention provides a method for inducing corn to generate haploid, which comprises the following steps: A) preparing a corn haploid induction line hybrid with the red-root purple plant character; B) pollinating the female parent corn by using the corn haploid induction line hybrid obtained by the step A as a male parent, harvesting fruit clusters, and selecting seeds with colorless embryos for sowing to obtain seedlings; and selecting the seedling with white root system color as a haploid plant. The induction line 'Jinyuan high induced hybrid No. I' prepared by the invention adopts a corn haploid induction identification technology to obviously improve the purity of identifying the corn haploid, and the purity is as high as 100 percent and is far higher than a control (generally about 70 percent). The method solves the key technical problem that the rate of the false haploids is overhigh in the process of identifying the haploids, thereby greatly improving the efficiency of identifying the haploids.

Description

Method for inducing and identifying haploid generated by corn

Technical Field

The invention relates to the field of agricultural plant breeding, in particular to a method for inducing and identifying corn to produce haploid.

Background

Corn is the grain crop with the largest planting area and the highest total yield in China, and the corn varieties applied in the current production are almost all hybrid seeds formed by compounding selfing lines. The method for breeding the inbred line by the traditional pedigree method adopts a continuous inbred method, at least more than 8 generations are needed from material composition to stability, and two generations are highly homozygous and stable by a method of inducing haploid to be doubled, so the method is called a double haploid breeding technology, because the method has the advantages of stable and fast inbred line, high degree of purity, accurate test result of matched combination, simple project management and the like, and is very suitable for commercial breeding.

The corn haploid inducer line commonly used at present is mostly from Stock6 and has two marker traits, grain Navajo stripe (controlled by A1A2C1C2R-nj complementary gene) and purple plant (controlled by A1A2C2BP1 complementary gene). These two marker traits appear dominant to the vast majority of maize material. The Rl-nj dominant anthocyanin color marker system is used for manually selecting haploid grains, all grains with purple embryos and purple endosperm aleurone layers are possible to be haploid, impurities can be removed in the jointing stage according to the color of leaves, purple plants are hybrid plants, and green plants are haploid. However, the Rl-nj gene is influenced by the genetic background of a parent and the environment, and the color expression is strong or weak, so that whether the haploid is identified by a machine or selected manually, the purity of the selected haploid is not 100 percent due to the limitation of the color development degree of different genetic backgrounds, the threshold setting of the machine or the proficiency of personnel, a large amount of hybrid plants exist in the field, continuous impurity removal is needed, a large amount of manpower and material resources are wasted, and if the pseudohaploid can be identified at an early stage, the subsequent workload is greatly reduced.

Therefore, it is very significant to explore a method for inducing and identifying the corn haploid, which is simple in operation method and suitable for large-scale operation.

Disclosure of Invention

An object of the present invention is to provide a method for inducing haploid production in maize.

The method provided by the invention comprises the following steps:

A) preparing a corn haploid induction line hybrid with the red-root purple plant character;

the preparation of the corn haploid induction line hybrid with the red-rooted purple plant character is to combine backcross breeding and haploid doubling to obtain the red-rooted purple plant induction line hybrid with high induction 3 and high induction 5 backgrounds;

B) and (3) hybridizing the corn haploid induction line obtained by the step A to induce corn to generate haploid.

In the method, the method for preparing the corn haploid inducer hybrid with the red-rooted purple plant character comprises the following steps:

1) respectively hybridizing the Nongda high trapping No. 3 and the Nongda high trapping No. 5 of the corn with the Nongda high trapping No. 1 to obtain F1 generation derived from the Nongda high trapping No. 3 and F1 generation derived from the Nongda high trapping No. 5;

2) respectively taking the F1 generation derived from the Nongda high attraction No. 3 and the F1 generation derived from the Nongda high attraction No. 5 as donor parents, and taking the Nongda high attraction No. 3 and the Nongda high attraction No. 5 corresponding to the donor parents as acceptor parents for backcross to obtain backcross filial generation derived from the Nongda high attraction No. 3 and backcross filial generation derived from the Nongda high attraction No. 5;

the backcross is specifically backcross of the generation F1 derived from the Nongda high-inducing No. 3 and the Nongda high-inducing No. 3; backcrossing with the generation F1 from the Nongda high trapping No. 5 and the Nongda high trapping No. 5;

3) respectively selecting plants with red roots and purple plants from the backcross progeny derived from the Nongda high trap No. 3 and the backcross progeny derived from the Nongda high trap No. 5 for respective selfing to obtain selfed progeny derived from the Nongda high trap No. 3 and selfed progeny derived from the Nongda high trap No. 5;

4) selecting haploid plants in the selfing progeny derived from the Nongda high-inducing No. 3 and the selfing progeny derived from the Nongda high-inducing No. 5 for doubling to obtain a DH line derived from the Nongda high-inducing No. 3 and a DH line derived from the Nongda high-inducing No. 5; in an embodiment of the invention, doubling is doubled by a root-soaking treatment with colchicine;

5) hybridizing the DH derived from the Nongda high-induction No. 3 and the DH derived from the Nongda high-induction No. 5 to obtain a corn haploid induction line hybrid;

in the method, in the step 2), the offspring after each backcross is subjected to character identification, and the offspring with the red roots and the purple plants (and the single plant with the plant type similar to that of the recurrent parent) is selected as the receptor parent of the next backcross.

In the above method, in step 2), the backcross is performed 3 times.

In the above method, the following steps are further included between step 4) and step 5): and (3) selfing and propagating the DH derived from the Nongda high-inducing No. 3 and the DH derived from the Nongda high-inducing No. 5 respectively.

In the method, in the step 4), the selected standard is a plant which has the characteristics of red roots and purple seedlings and is identified as a haploid by the dyeing of the root tip.

In the step B), the corn haploid induction line hybrid obtained by the step A is used for inducing the corn to generate the haploid, the corn haploid induction line hybrid obtained by the step A is used as a male parent to pollinate a female parent corn, fruit clusters are harvested, seeds with colorless embryos are selected, and the plant with white root system color after sowing is used as the haploid plant.

Still another object of the present invention is to provide a method for preparing a corn haploid inducer line.

The preparation method provided by the invention comprises the step A in the method of the first object, and the corn haploid inducer hybrid is obtained, namely the corn haploid inducer.

The application of the method in the induction of the corn haploid is also the protection scope of the invention;

or, the application of the method in improving the corn haploid inductivity is also within the protection scope of the invention;

or, the application of the method in improving the haploid differentiation rate of the corn is also within the protection scope of the invention;

alternatively, the application of the method in improving the haploid purity of the corn is also within the protection scope of the invention.

The invention combines backcross breeding and haploid doubling to obtain the red root purple plant induction line with high induction 3 and high induction 5 backgrounds and prepares a hybrid-Jinyuan high induction hybrid number one, the root of the induction line hybrid is red, the stem, anther and glume are purple, the leaves are red and green, the pollen amount is large, and the induction rate is more than 10%. The Jinyuan high-induction hybrid No. one is adopted as a male parent to pollinate the induced material, more than 10 percent of pseudohaploids can be picked out from the induced material, the pseudohaploids can be judged according to the color of roots after the pseudohaploids are bred, white roots are haploids, and red roots are eliminated when being hybridized with an induction line. In contrast, the induced material is pollinated by the induction lines of high induction 3 and high induction 5, the color expression is strong or weak under the dual influence of the genetic background and the environment of the parent, so that the purity of the selected haploid is not 100% no matter machine identification or manual selection, the selected haploid is not 100% due to the limitation of the color development degree of different genetic backgrounds, the threshold setting of a machine or the proficiency of personnel, the plants of the induction lines of high induction 3 and high induction 5 are green, the roots of the plants are white, and the pseudohaploid is planted in the field and has a large amount of hybrid plants, so that continuous impurity removal is needed, and a large amount of manpower and material resources are wasted.

The invention can adopt an artificial pollination method. The induction line 'Jinyuan high induction hybrid No. one' is staggered for a plurality of times, the female parent is sowed once, pollen is collected from the induction line manually to pollinate the female parent, the planting density of the female parent is 3000-12000 plants per mu, and the female parent can be F1 or a segregating population. The female parent is emasculated completely, each cluster is pollinated only once, and the segregating population can select a single plant with an ideal plant type for pollination.

The invention can also adopt an isolation region production method using an induction line as a male parent. When the cultivation is carried out in an isolation area, the induction line Jinyuan high induction hybrid No. I is taken as a male parent, and the proper row ratio is taken as the male parent: the female parent is 1: 3-1: 9. the mother-mother rows are sowed in the same period, the male parents are sowed in two periods, one meter is planted in each period, and the male parents are planted at intervals. In order to ensure enough pollen, the male parent can also be sown in the row ratio of the female parent at the middle period, the plant spacing is 0.2-1 m, the female parent is completely emasculated, and the isolated population can be artificially cut off undesired single plants.

When the female parent is finished and a black layer appears, haploids are manually or mechanically selected, the purity of the selected haploids is not high, the haploids are used for raising seedlings, the color of roots can be judged, white roots are haploids, and red roots are hybrid plants.

The induction line 'Jinyuan high induced hybrid No. I' prepared by the invention adopts a corn haploid induction identification technology to obviously improve the purity of identifying the corn haploid, and the purity is as high as 100 percent and is far higher than a control (generally about 70 percent). The method is independent of laboratory operation, and is suitable for large-scale batch identification of haploids. The method solves the key technical problem that the rate of the false haploids is overhigh in the process of identifying the haploids, thereby greatly improving the efficiency of identifying the haploids.

Drawings

FIG. 1 shows a haploid inducer Jinyuan high induction No. one.

FIG. 2 shows induced material inducing detasseling of haploid isolation regions.

FIG. 3 shows pseudohaploid seedling raising.

Detailed Description

The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Unless otherwise specified, the seeds used in the examples can be purchased by a hybridization method or a market, and the technical means used in the examples are conventional means well known to those skilled in the art.

Nongda GaoChi No. 1 is described in Liangbang, Sujun, Lichuxia, Golgih, Song tin chapter, Hades Huqin, Huguanhui, Wangming spring, Nongda GaoChi No. 1 for the study of different germplasm and generational haploid induction frequencies in maize [ J ] maize science, 2008(05): 3-6; the inductivity is low, but the plants are purple, and the roots are red;

agro-high attraction No. 3 is described in the following documents: yueyao yao sea, Zhanxin, Zhou Xudong, Luming, Zhang Shijun, Mayinji, Liyan, Liuwen, Wang Shaoxing, corn haploid field natural hybridization induction efficiency preliminary analysis [ J ] crop journal, 2013(06): 39-41; the inductivity is higher and reaches 7%, but the whole plant is green, and the root is white;

agro high attraction No. 5 is described in the following documents: comparison of the effects of the haploid inducer of maize on different maternal sources [ J ] Zengyun, 2015,23(02):25-27+ 32; the average induction rate was 9.76%, but the whole plant was green and the roots were white.

Example 1 preparation of corn haploid inducer line

A corn haploid induction line hybrid with the red root purple plant character, namely Jinyuan high induction hybrid No. I, is prepared according to the following method:

1. hybridization of

In 5 months of 2015, 10 strains of Nongda GaoChi No. 3 are used as female parents, 5 strains of Nongda GaoChi No. 1 are used as male parents for hybridization, and F1 generations of 5 ears derived from Nongda GaoChi No. 3 are obtained and mixed for threshing;

in 5 months of 2015, 10 strains of Nongda GaoChi No. 5 are used as female parents, 5 strains of Nongda GaoChi No. 1 are used as male parents for hybridization, and F1 generations of 5 ears derived from Nongda GaoChi No. 5 are obtained and mixed for threshing.

2. Backcrossing

In 11 months of 2015, 25F 1 generation sown plants derived from the Nongda Gaojin No. 3 and 25F 1 generation sown plants derived from the Nongda Gaojin No. 5 are respectively used as female parents, the F1 single plants are expressed as red roots and purple plants, 5 Nongda Gaojin No. 3 and 5 Nongda Gaojin No. 5 corresponding to the red roots and purple plants are used as recurrent parents, backcross is carried out for 1 generation to obtain 10 BC1 generations (Nongda Gaojin No. 3 background) and 10 BC1 generations (Nongda Gaojin No. 5 background), and strains of each background are mixed for threshing;

after all the BC1 generations are cultivated in 1 month of 2016, through observation, only BC1 generations with red root and purple plant characters are reserved, single plants which are similar to the plant types of the round parent Nonggao high attraction No. 3 and Nonggao high attraction No. 5 are selected before pollination, BC1 generations with 200 Nonggao high attraction No. 3 backgrounds and BC1 generations with 200 Nonggao high attraction No. 5 backgrounds are selected as female parents, 50 Nonggao high attraction No. 3 and 50 Nogao high attraction No. 5 corresponding to the female parents are selected as round parents, backcross is carried out for 2 generations, and BC2 generations (Nogao high attraction No. 3) 50 ears and BC2 generations (Nogao high attraction No. 5) 50 ears are obtained and threshed respectively;

and (3) sowing the BC2 generation according to the rows of ears in 5 months in 2016, observing, only reserving BC2 generation plants with red root and purple plant characters, selecting single plants with similar plant types to the farming high attraction No. 3 and the farming high attraction No. 5 of the recurrent parent respectively before pollination, selecting 100 BC2 generations with the farming high attraction No. 3 background and 100 BC2 generations with the farming high attraction No. 5 background as female parents and 20 corresponding farming high attraction No. 3 and 20 farming high attraction No. 5 as recurrent parents, and performing backcross for 3 generations to obtain 50 ears of BC3 generation (farming high attraction No. 3) and BC3 generation (farming high attraction No. 5) 50 ears.

3. Selection of haploid

The BC3 generation ears with the background of Nongda high inducing No. 3 and Nongda high inducing No. 5 are threshed and sown in 2016 (11 months), seedlings with red root and purple seedling characters are manually selected, and 400 plants and 500 plants are obtained respectively.

The pseudohaploid seedlings are subjected to root tip staining (cutting root tips for cytological tabletting and observing the number of chromosomes, cutting corn root tips for 2-3mm, putting the corn root tips into a saturated p-dichlorobenzene aqueous solution, soaking for 3-4 h, taking out, fixing for 24h by using a Carnot fixing solution (95% ethanol: glacial acetic acid ═ 3: 1), transferring into 70% alcohol, preserving in a 4 ℃ refrigerator, washing for several times by using ddH2O, adding a mixture of cellulase (2%) and pectinase (0.5%), dissociating for 4-5 h in a 28 ℃ refrigerator, tabletting, and observing the number of chromosomes under a microscope.

The normal number of maize chromosomes is 2 n-20, and the number of haploid chromosomes is n-10.

After root tip staining, 40 BC3 haploid seedlings derived from Nongda high-inducing No. 3 and 50 BC3 haploid seedlings derived from Nongda high-inducing No. 5 are obtained in total, and the seedlings have the properties of red roots and purple seedlings.

4. Haploid doubling and DH propagation

In 2016, 11 months, the haploid seedlings derived from the Nongda high-inducing No. 3 BC3 generation and the haploid seedlings derived from the Nongda high-inducing No. 5 BC3 generation are doubled by root soaking treatment with colchicine, 4 haploid strains derived from the Nongda high-inducing No. 3 normally fruit to obtain a DH line, and 5 haploid strains derived from the Nongda high-inducing No. 5 normally fruit to obtain the DH line.

The above-mentioned method for doubling the colchicine root-soaking treatment is referred to the following documents: the application research of the haploid technology in corn breeding is advanced [ J ] in Helongjiang agricultural science, 2009(04):15-17+20, and specifically, the root system of the haploid seedling is soaked in 0.05% (mass-volume ratio g: ml) of colchicine solution for 24 hours, and then is washed with clean water and transplanted to the field.

And in 2017, in 1 month, sowing the harvested DH lines according to ear rows, performing cytological identification according to the root tip dyeing method of the 3, wherein the DH lines derived from the Nongda Gaoinduced No. 3 and the Nongda Gaoinduced No. 5 respectively have good self pollination and represent red root purple plants, recovering all chromosome data to be 20, and obtaining normal diploid, and the result proves that the DH ear rows derived from the Nongda Gaoinduced No. 3 and the Nongda induced No. 5 are successfully doubled and are respectively named as Gaoinduced 3RR and Gaoinduced 5 RR.

5. Obtaining of Jinyuan high trap No. one

1) Obtaining of Jinyuan high trap No. one

Respectively selfing and propagating the high-trapping 3RR and the high-trapping 5RR in 2017 in 5 months; the offspring of each strain still shows red roots and purple plants, and the stable inheritance of the characters is proved.

And (3) pollinating 100 plants with the height of inducing 5RR by using 20 plants with the height of inducing 3RR pollen in 12 months in 2017 to obtain a corn haploid induction line hybrid, and naming the corn haploid induction line hybrid as Jinyuan high induction hybrid first.

2) Phenotypic observations

The root of Jinyuan Ganzhao No. one (figure 1) is red and the plant is purple. The seedlings are sowed in spring in a Jinyuan seed breeding station of Zhangye city in Gansu province, the plant height is 3.2 m, the number of male flower branches is more than 9, and the pollen quantity is large.

Example 2 application of Jinyuan high-induction hybrid No. one of corn haploid induction line in induction of corn haploid

One-time induction of Jinyuan high-level hybrid one-time induction of corn haploid by artificial pollination

1. Artificial pollination

The corn haploid induction method provided by the embodiment comprises the following steps:

1) in late spring 4 months, in the breeding base of the Jinyuan seed industry in the cisterm region of Beijing city, the hybrid seed of the corn haploid induction line obtained in the example 1, Jinyuan high induction hybrid one (male parent) is staggered for a plurality of times, Vitaceae 702 (Henan Jinyuan seed industry, Ltd.) is taken as the material to be induced (female parent) and is sowed once at the second stage of sowing of the induction line, 110 plants are sowed by the female parent, and the planting density is 4000 plants/mu.

2) Before the female parent is castrated, the female parent is castrated with bracts (figure 2), and the female ear is bagged. When the filaments are completely discharged, pollen of an induction line is manually collected, anther shells are filtered by a silk screen, the pollen is introduced into a bamboo tube, the opening of the bamboo tube is covered with gauze, a rubber ring is used for fastening, female parents are pollinated, each fruit ear is pollinated once, and an isolated population can select an ideal single plant for pollination.

2. Haploid identification of corn

1) Harvesting 100 artificially pollinated induced ears of 1 in the last 9 th ten days of autumn, enucleating the uncolored contaminated seeds of the endosperm with a screwdriver, holding the ears with the left hand, enabling the tops of the ears to face the face, so that the positions of the embryos can be easily identified by eyes, and the seeds are deducted by the right hand, wherein the embryos are pseudomonoploid if the embryos have no color; if the embryo has purple mark, it is diploid that normally crosses with the induction line, and needs to be eliminated.

As a result, 2200 pseudohaploid kernels were selected from 20000 kernels.

2) At the beginning of 11 months, 2200 screened pseudohaploid seeds screened in the step 1) are sowed in a seedling tray in a breeding base of the Aster species of Susan city, Hainan province, river sand is used as a matrix, each hole is sowed with a depth of 2 cm, and the seeding is watered thoroughly. Because the hybrid seedlings emerge faster than the haploid seedlings and have strong germination potential, the seedlings with exposed tips are pulled out, and a part of pseudohaploids are eliminated; and lifting the seedlings after the seedlings emerge and cleaning the seedlings.

If the root color of the seedling is red, the seedling is a pseudohaploid of the induction line hybridization and is eliminated;

and if the root system color of the seedling is white, the seedling is a true haploid.

The result 2200 is that 2000 haploid seedlings are obtained by eliminating the pseudohaploids (fig. 3, white roots (left side) are haploid, red roots (right side) are eliminated by crossing with the induction line).

The pseudohaploid inductivity is (pseudohaploid seed number (2200)/total induced seed number (20000)) × 100%;

true haploid inductivity ═ number of true haploids (2000)/total number of induced seeds (20000)) × 100%.

The pseudohaploid inductivity of the Jinyuan high-induction hybrid No. I is 11%, and the true haploid inductivity is 10%.

3) Transplanting the 2000 haploid seedlings (total plants) into a field to obtain 2000 real haploid plants.

The seedling leaves expressed in the field are narrow, the typical characteristics of the haploids are presented, the purple plant marker is not existed, 50 haploids are randomly extracted for carrying out dyeing physical examination according to the root tip dyeing method of the 3, and the result proves that all the 50 haploids are haploids, which indicates that the method can ensure that all the plants transplanted to the field are haploids, and the haploid recognition rate is improved to 100%.

The haploid identification rate is equal to the number of true haploid plants (2000)/the number of total plants (2000) × 100%

II, Jinyuan high-induced hybrid I corn haploid induction through isolation region

1. Corn haploid isolation region

1) in late spring 4 months, in the breeding base of Jinyuan seed industry in Zhangye city, Gansu province, the induction line "Jinyuan high induced hybrid No. I" obtained in example 1 is used as a male parent, and the proper row ratio is as the male parent: the female parent is 1: 6. female parent Vitaceae 702 (Henan Jinyuan Seisakusho Co., Ltd.) was sown at the first stage, and male parents were sown at the second stage and the third stage in rows, one meter was planted at each stage, and they were planted at intervals. In order to ensure enough pollen, the male parent is planted at the same period of the row ratio of the female parent and the plant spacing is 0.5 m, which is called the babysbreath. Half of the male parent in the row proportion is subjected to pregermination, and half is not subjected to pregermination.

2) The female parent is emasculated with bracts, and the single plant which is not ideal is cut off manually. And cutting off all male parent single plants after pollination is finished.

2. Haploid identification of corn

1) Harvesting 200 induced ears of the 1 isolation regions in the last 9 th day of autumn, enucleating the uncolored contaminated seeds of the endosperm with a screwdriver, holding the ears with the left hand, enabling the tops of the ears to face the face, so that the positions of the embryos can be easily identified by eyes, and the seeds are deducted by the right hand, wherein the embryos are pseudomonoploid if the embryos have no color; if the embryo has purple mark, it is diploid crossing with the induction line normally, and needs to be eliminated.

In total, 4150 pseudohaploid kernels were selected from 40000 kernels (total number of induced kernels).

2) At the beginning of 11 months, in a breeding base of the Aster species of the third City in Hainan province, 4150 pseudohaploid seeds screened in the step 1) are sowed in a seedling tray, river sand is used as a matrix, each hole is sowed with a depth of 2 cm, and the seeding tray is watered thoroughly. Because the hybrid seedlings emerge faster than the haploid seedlings and have strong germination potential, the seedlings with exposed tips are pulled out, and a part of pseudohaploids are eliminated; and lifting the seedlings after the seedlings emerge and cleaning the seedlings.

If the root color of the seedling is red, the seedling is a pseudohaploid hybridized with the induction line and is eliminated;

if the root system color of the seedling is white, the seedling is haploid.

The result shows that 4050 true haploid seedlings are obtained from 4150 pseudohaploid seeds.

The pseudohaploid inductivity is (pseudohaploid seed number (4150)/total induced seed number (40000)) × 100%;

true haploid inductivity ═ number of true haploids (4050)/total number of seeds induced (40000)) × 100%.

The induction rate of the pseudohaploidy of the Jinyuan Ganzhao No. I is 10.38 percent, and the induction rate of the real haploid is 10.1 percent.

3) And (3) transplanting 4050 haploid seedlings (total number of plants) into a field to obtain 4000 haploid plants.

And 3, root tip dyeing is carried out on 50 haploid plants according to the method 3, and the result proves that all 50 haploid plants are haploids, which shows that the method can ensure that all the plants transplanted to the field are haploids, and the haploid identification rate is 100%.

The haploid identification rate is equal to the number of true haploid plants (4000)/the total plants (4000). times.100%

Comparative example:

the method of the first embodiment 2 is adopted, the induction line is replaced by the height induction No. 5, as a result, 2100 pseudohaploid seeds are selected from 20000 seeds, the 2100 haploid seedlings are transplanted to the field, 630 plants are found to have wide leaves and high plant heights, 50 plants are taken to carry out root tip dyeing according to the method of the 3, and the result proves that the number of 50 chromosomes is 20, the plants are diploid, the 50 plants with narrow leaves and low plant heights are taken to carry out root tip dyeing according to the method of the 3, the haploid identification rate is determined to be haploid, and the calculated haploid identification rate of the height induction No. 5 is only 70%.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method for inducing corn to generate haploid, comprising the following steps:

B) using the corn haploid induction line hybrid obtained by A to induce corn to generate haploid;

the method for preparing the corn haploid induction line hybrid with the red-rooted purple plant character comprises the following steps:

4) selecting haploid plants in the selfing progeny derived from the Nongda high-inducing No. 3 and the selfing progeny derived from the Nongda high-inducing No. 5 for doubling to obtain a DH line derived from the Nongda high-inducing No. 3 and a DH line derived from the Nongda high-inducing No. 5;

in the step 2), performing character identification on the filial generation after each backcross, and selecting the filial generation with the red roots and the purple plants as a receptor parent of the next backcross;

in the step 2), the backcross is performed for 3 times;

the method also comprises the following steps between the step 4) and the step 5): selfing and propagating the DH derived from the Nongda high-inducing No. 3 and the DH derived from the Nongda high-inducing No. 5 respectively;

in the step 4), the selected standard is a plant which has the characteristics of red roots and purple seedlings and the root tip is identified as a haploid after being dyed;

in the step B), the corn haploid induction line hybrid obtained by the step A is used for inducing corn to generate haploid, the corn haploid induction line hybrid obtained by the step A is used as a male parent to pollinate female parent corn, fruit ears are harvested, seeds with colorless embryos are selected, and the plant with white root system color after sowing is a haploid plant.

2. A method for preparing a corn haploid inducer line, comprising the step A of the method of claim 1, wherein the corn haploid inducer line hybrid is obtained, namely the corn haploid inducer line.

3. Use of the method of claim 1 for inducing maize haploids;

or, the use of the method of claim 1 to increase corn haploid inductivity;

or, the use of the method of claim 1 to increase the haploid discrimination rate of maize;

or, the use of the method of claim 1 to increase haploid purity in maize.