Maize pure line breeding method combined with population improvement

Abstract

The invention relates to the technical field of corn breeding, in particular to a corn pure line breeding method combined with population improvement, which is technically characterized by comprising the following steps: (1) breeding population creation; (2) carrying out parent pure line breeding and population mutual recurrent improvement; by continuously and circularly repeating the work of the step (2), while continuously improving the combining ability of the two groups PA and PB, continuously breeding excellent pure-line hybrids and PA * PB hybrids belonging to a heterosis mode. By means of the method, the excellent genes are continuously polymerized, the excellent gene frequency of the corn pure line and the breeding population is improved, and the purpose of circularly improving the corn pure line and the corn breeding population is achieved; breeding populations and pure lines of two dominant populations in a heterosis mode can be improved at the same time; and the generation of substantive derived varieties can be effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of corn breeding, and in particular to a method for corn pure line breeding combined with population improvement. Background Art

[0002] Corn is an important food crop in my country. At present, the corn varieties planted in agricultural production are mainly hybrids formed by the combination of homozygous inbred lines. Therefore, the selection of inbred lines is a key link in corn breeding. By using the haploid breeding method, stable genetic inbred line materials can be quickly selected, greatly shortening the breeding cycle.

[0003] The existing techniques for breeding pure lines of corn (inbred lines, DH lines) mainly use the two-ring breeding method and the backcross breeding method. However, the methods in the existing techniques have the following shortcomings:

[0004] 1. It is usually not possible to improve the breeding populations and pure lines of two dominant groups in a heterosis model at the same time;

[0005] 2. It cannot effectively avoid the production of substantially derived varieties (pure lines).

[0006] To this end, based on the above problems, the present application provides a method for pure line breeding of corn combined with population improvement to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to solve the prior art problems raised in the above background technology and to provide a method for pure line breeding of corn combined with population improvement.

[0008] The above-mentioned purpose of the present invention is achieved like this:

[0009] The solution provided by the present invention is a method for pure line breeding of corn combined with population improvement, and the breeding method comprises the following steps:

[0010] (1) Creation of breeding population:

[0011] According to the maize heterosis model (PA×PB), multiple superior inbred lines with target traits from the same heterosis group were used for pairwise hybridization, and then the seeds of each hybrid combination were mixed in equal amounts and planted in an isolated area for open pollination for two generations to obtain two superior groups C belonging to the heterosis model. 0 Breeding colony, or PAC 0 Groups and PBC 0 group;

[0012] (2) Carry out pure line breeding of parents and population cycle improvement:

[0013] (2.1) Planting PAC 0Groups and PBC 0 250 to 300 plants were selected from each group for continuous self-pollination selection for 2 generations to obtain a batch of PAC 0 Groups and PBC 0 Group S 2 After inbreeding, PAC 0 , PBC 0 The groups were used as test species and were compared with PBC 0 S 2 、PAC 0 S 2 , new and excellent germplasm materials, and obtained a batch of PBC 0 S 2 ×PAC 0 、New excellent germplasm×PAC 0 、PAC 0 S 2 ×PBC 0 、New excellent germplasm × PBC 0 After the test cross combination, the yield and resistance of the test cross combination were identified, and the PAC 0 S 2 , PBC 0 S 2 , resistance identification of foreign excellent germplasm;

[0014] According to the criteria of high combining ability and good comprehensive resistance, 20% of S were selected from each population. 2 As PAC 1 , PBC 1 Synthetic materials; 20% PAC selected 0 S 2 , PBC 0 S 2 The same amount of seeds were taken from the same group of foreign excellent inbred lines and other germplasms, and then planted in different isolation areas for open pollination and selected for 2 generations to obtain PAC 1 , PBC 1 group;

[0015] (2.2) 20% of PACs are selected from the above 0 S 2 , PBC 0 S 2 Select 3-5 S with the best combining ability and comprehensive resistance 2 As basic materials, inbred lines or DH lines are selected by pedigree method or haploid breeding technology for hybrid breeding and PAC 2 , PBC 2 synthesis;

[0016] (2.3) Repeat step 2.2) in a continuous cycle to continuously improve the combining ability of the two populations PA and PB, and continuously breed excellent pure lines and hybrids belonging to the heterotic model PA×PB.

[0017] Furthermore, in step (1), there are 8-10 excellent inbred lines having the target trait and coming from the same heterotic group.

[0018] The difficulty and significance of the technical problem solved by the present invention are:

[0019] Based on the establishment of the system of substantially derived varieties, the corn seed industry, especially the research on pure line breeding technology of corn, has received more and more attention in recent years, and strengthening the original innovation of pure line breeding technology of corn in the corn seed industry has become an inevitable trend. The present invention has created a new technology of pure line of corn hybrid parents through research, and the application of the invention technology to breed pure line of parents can effectively avoid the generation of substantially derived varieties.

[0020] Compared with the prior art, the method for pure line breeding of corn combined with population improvement provided by the present invention has the following beneficial effects:

[0021] 1. Through the breeding method of the present invention, the pure lines of corn and the corn breeding population can be improved simultaneously and cyclically;

[0022] 2. Through the breeding method of the present invention, excellent genes can be continuously aggregated to increase the frequency of excellent genes in pure lines and breeding populations of corn;

[0023] 3. Through the breeding method of the present invention, the breeding population can be continuously improved in the process of continuously breeding pure lines of corn hybrid parents;

[0024] 4. Through the breeding method of the present invention, the breeding populations and pure lines of two superior groups in a heterosis model can be improved at the same time;

[0025] 5. The breeding method of the present invention can effectively avoid the generation of substantially derived varieties and overcome the defects of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a method in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] The implementation of the present invention is described in detail below in conjunction with specific embodiments.

[0029] Terminology explanation:

[0030] 1. Pure corn lines refer to the self-pollinated offspring from a single corn plant that have uniform and consistent traits obtained through continuous self-pollination and selection for multiple generations, and are relatively genetically stable, or the doubled haploids (also called DH lines) obtained using haploid breeding technology.

[0031] 2. Corn population improvement is to create and improve the basic material for corn breeding by gradually increasing the frequency of favorable genes in the population through recurrent selection of the basic population to improve the performance of the population.

[0032] Reference Figure 1 As shown, the following are preferred embodiments provided by the present invention.

[0033] The embodiment of the present invention provides a method for pure line breeding of corn combined with population improvement, the breeding method comprising the following steps:

[0034] Step 1: Creation of breeding population:

[0035] According to the maize heterosis model (PA×PB), multiple (8-10) superior inbred lines with target traits from the same heterosis group were used for pairwise hybridization. The seeds of each hybrid combination were mixed in equal amounts and planted in an isolated area for open pollination selection for 2 generations. Two superior groups C belonging to the heterosis model PA×PB were obtained. 0 Breeding colony, or PAC 0 Groups and PBC 0 group.

[0036] Step 2: Carry out pure line breeding of parents and population cycle improvement:

[0037] 1. Planting PAC 0 Groups and PBC 0 250 to 300 plants were selected from each group for continuous self-pollination selection for 2 generations to obtain a batch of PAC 0 Groups and PBC 0 Group S 2 After inbreeding, PAC 0 , PBC 0 The groups were used as test species and were compared with PBC 0 S 2 、PAC 0 S 2 , new and excellent germplasm materials, and obtained a batch of PBC 0 S 2 ×PAC 0 、New excellent germplasm×PAC 0 、PAC 0 S 2 ×PBC 0、New excellent germplasm × PBC 0 After the test cross combination, the yield and resistance of the test cross combination were identified, and the PAC 0 S 2 , PBC 0 S 2 , foreign excellent germplasm for resistance identification, according to the standard of high combining ability and good comprehensive resistance, select 20% S from each group 2 As PAC 1 , PBC 1 Synthetic materials. From the selected 20% PAC 0 S 2 , PBC 0 S 2 The same amount of seeds were taken from the same group of foreign excellent inbred lines and other germplasms, and then planted in different isolation areas for open pollination and selected for 2 generations to obtain PAC 1 , PBC 1 group.

[0038] 2. Based on the above steps, 20% of the selected PACs 0 S 2 , PBC 0 S 2 Each selection has 3-5 selected S with the best combining ability and comprehensive resistance. 2 As basic material, pedigree method or haploid breeding technology is used to select inbred lines or DH lines for hybrid breeding and PAC 2 , PBC 2 synthesis.

[0039] Then, the work in step 2 is repeated in a cycle. While the compatibility of the two groups PA and PB is continuously improved, excellent pure lines and hybrids belonging to the hybrid advantage model PA×PB can be continuously bred.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for pure line breeding of corn combined with population improvement, characterized in that: The breeding method comprises the following steps: (1) Creation of breeding population: According to the maize heterosis model (PA×PB), multiple superior inbred lines with target traits from the same heterosis group were used for pairwise hybridization, and then the seeds of each hybrid combination were mixed in equal amounts and planted in an isolated area for open pollination selection for 2 generations, thus obtaining two dominant group C0 breeding populations belonging to the heterosis model (PA×PB), namely, the PAC0 population and the PBC0 population; (2) Carry out pure line breeding of parents and population cycle improvement: (2.1) Plant the PAC0 and PBC0 populations, and select 250 to 300 plants from each population for continuous self-pollination selection for 2 generations. After obtaining a batch of S2 inbred lines of the PAC0 and PBC0 populations, use the PAC0 and PBC0 populations as test varieties and mate them with PBC0S2, PAC0S2, and excellent new germplasm materials, respectively, to obtain a batch of PBC0S2×PAC0, new excellent germplasm×PAC0, PAC0S2×PBC0, and new excellent germplasm×PBC0 test cross combinations. Then, conduct yield and resistance identification on the test cross combinations, and conduct resistance identification on PAC0S2, PBC0S2, and foreign excellent germplasm; According to the standards of high combining ability and good comprehensive resistance, 20% of S2 were selected from each population as the synthetic materials of PAC1 and PBC1; equal amounts of seeds were taken from the selected 20% PAC0S2, PBC0S2 and foreign excellent inbred lines from the same population, mixed and planted in different isolation areas, and selected for 2 generations after open pollination to obtain PAC1 and PBC1 populations; (2.2) 3-5 S2 with the best combining ability and comprehensive resistance are selected from the above 20% PAC0S2 and PBC0S2 as basic materials, and inbred lines or DH lines are selected by pedigree method or haploid breeding technology for hybrid breeding and PAC2 and PBC2 synthesis; (2.3) Repeat steps (2.1) and (2.2) in a continuous cycle to continuously improve the combining ability of the two populations PA and PB, while continuously breeding excellent pure lines and hybrids belonging to the hybrid advantage model PA×PB.

2. A method for pure line breeding of corn combined with population improvement according to claim 1, characterized in that: In step (1), there are 8 to 10 excellent inbred lines having target traits and coming from the same heterotic group.

Images