Method for rapidly breeding by using short-growth-cycle material and application of short-growth-cycle material

Abstract

The invention discloses a method for rapidly breeding by using a short-growth-cycle material and application of the short-growth-cycle material. Wheat germplasm L2128 which carries a Vrn-Ala gene, does not need vernalization and has excellent agronomic characters is used as a recurrent parent, and target characters are introduced into the genetic background of the recurrent parent through hybridization and continuous backcross. The method specifically comprises the steps that a target parent is selected to be hybridized with L2128, multi-generation backcross is carried out under the illumination culture condition of 22 hours at the temperature of 25 DEG C, and about two months are consumed for each generation; and screening a backcross generation carrying the Vrn-Ala gene and the target character by using a molecular marker, and finally obtaining the stable material with the homozygous background of L2128. The method breaks through the limitation of vernalization and long period in traditional breeding, the strain homozygosis time is shortened from 6 years to 1 year, and 6 generations can be bred in one year. The method is suitable for rapidly constructing genetic populations, developing molecular markers and breeding disease-resistant high-quality varieties. The method is simple and convenient to operate and low in cost, and provides an efficient technical means for accelerating wheat breeding.

Description

Technical Field

[0001] The invention belongs to the technical field of agriculture, and in particular relates to a method for using a short growth cycle material for rapid breeding and application thereof. Background Art

[0002] The long wheat breeding cycle is a key problem that plagues breeders in the selection of new varieties. Shortening the wheat breeding cycle is an important means to improve breeding efficiency. Traditional breeding needs to go through 7-8 generations of self-pollination and selection after hybridization to produce strains with a stable genetic background before they can be used for experimental research. For winter wheat varieties, it takes 4-8 weeks of vernalization to enter the reproductive growth stage and complete the growth cycle. For experiments such as gene positioning and gene map cloning that require the construction of populations, shortening the wheat growth cycle is crucial to speed up the experimental process. How to shorten the stabilization time of wheat strains is an urgent problem to be solved in breeding. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned problems and provide a method and application of short growth cycle materials for rapid breeding. This laboratory has previously created a new wheat germplasm L2128 that does not require vernalization, has a short growth cycle, and can safely overwinter. The target material is hybridized with L2128 and continuously backcrossed to obtain a new germplasm with L2128 background, which has the characteristics of not requiring vernalization, short growth cycle, safe overwintering, and carrying the target gene. This germplasm can shorten the time for wheat lines to become homozygous and speed up the construction of wheat genetic populations.

[0004] The specific technical solutions are as follows:

[0005] The present invention provides a method for using short growth cycle materials for rapid breeding, comprising the following steps:

[0006] Step 1. Select parent material A and cross it with wheat germplasm L2128

[0007] In October, the selected parent material A and wheat germplasm L2128 are planted in the field. According to the investigation results of the flowering period of the parents, the sowing date of parent A and L2128 is arranged in time to ensure that the flowering periods of the parents coincide when hybridization is performed; during the flowering period of wheat, parent A and L2128 are hybridized, and the hybrid ears are harvested, threshed, and grains are harvested in June of the first year when the wheat is mature;

[0008] Step 2. F1 and L2128 were backcrossed in the culture room to obtain BC1F1

[0009] The F1 grains and L2128 obtained in step 1 are germinated at room temperature. The germinated seeds are directly sown into a seedling pot with a diameter of 30 cm and a height of 20 cm containing a substrate without vernalization treatment. Six seeds of each material are sown in each pot. The seeds are placed in a culture room at 25°C, with a light duration of 22 hours per day, a light intensity of 600 Lux or more, and a humidity of 60-70%. Watering is required during the growth period. With F1 as the female parent and L2128 as the male parent, hybrid ears are harvested about 20-25 days after artificial pollination. The harvested ears are placed in a drying room at 55°C for 10-12 hours, and threshed manually to obtain BC1F1. The entire step 2 takes about 2 months.

[0010] Step 3. Select the BC1F1 generation with the target trait and backcross it with L2128 in the culture room

[0011] In August of the first year, the BC1F1 grains obtained in step 2 and the parent L2128 are planted in the culture room; the planting method and culture conditions are the same as step 2; DNA is extracted from BC1F1 plants at the three-leaf stage of wheat, and BC1F1 plants carrying the Vrn-A1a gene and the target gene in parent A are selected (if there is no suitable marker for the target trait of parent A, screening is performed based on the phenotype), and the plants with a short heading period and good agronomic traits are marked with a card. During the flowering period, the marked BC1F1 plants are hybridized with L2128, and the hybrid ears are harvested about 20-25 days after artificial pollination; the offspring BC2F1 that does not require vernalization, has a short heading period, and carries the target gene (or target trait) of parent A is obtained;

[0012] Step 4. Continuous backcross selection of BC2F1 and L2128 in the growth chamber to obtain target materials

[0013] According to the genotype and phenotype selection method of the BC1F1 population in step 3, after obtaining BC2F1, the same method is used to obtain BC3F1, BC4F1, ...; each generation takes about 2 months, 6 generations can be obtained in a year, and the offspring BC5F1 can be obtained in April of the second year. The BC5F1 generation has met the basic requirements of L2128 as a genetic background. In the culture room, BC5F1 is self-pollinated for one generation, and the target material with L2128 genetic background homozygous that does not require vernalization, has a short heading period, and has the target traits of parent A is obtained according to the planting and screening method in step 2.

[0014] Preferably, in step 1, each hybrid ear is ensured to have at least 20 spikelets, and the number of hybrid ears is not less than 2.

[0015] Preferably, the BC1F1 population generated in step 2 is used for phenotypic and genotypic screening and for subsequent hybridization with L2128, and the hybrid ear with its F1 as the mother parent is guaranteed to have at least 20 spikelets and the number of hybrid ears is not less than 10.

[0016] Compared with the prior art, the present invention has significant beneficial effects:

[0017] The method of the present invention can avoid the vernalization stage of winter wheat, shorten the stable years of wheat strains, shorten the acquisition of stable strains from 6 years to the current 1 year, create new germplasm materials for rapid breeding, and quickly construct genetic analysis populations. Using this method, we hybridized L2128 with scab-resistant materials such as Nanhuai wheat 191, Nanhuai wheat 193, and Bainong 4199, and obtained stable strains in a relatively short period of time, and the stable strains have the characteristics of not requiring vernalization, short growth cycle, and carrying scab-resistant genes. This proves the feasibility of the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the hybridization of Nanhuai wheat 191 and wheat germplasm L2128 to obtain a stable strain. DETAILED DESCRIPTION

[0019] The following uses Nanhuai wheat 191 as a parent example and further illustrates the technical solution of the present invention in conjunction with the accompanying drawings.

[0020] The Vrn gene is a vernalization gene. When the genotype is Vrn / Vrn or Vrn / vrn, heading can be produced without vernalization. When the genotype is vrn / vrn, vernalization is required for heading to occur.

[0021] Fhb is a Fusarium fusarium gene, which can lead to strong resistance to Fusarium fusarium.

[0022] Step 1: hybridize Nanhuai wheat 191 with wheat germplasm L2128 to obtain F1

[0023] Nanhuai wheat 191 is a winter material that requires 8 weeks of vernalization before entering the reproductive growth stage. It carries the ergot resistance gene Fhb-1 and has good ergot resistance traits. L2128 is a material that carries the vernalization dominant gene Vrn-A1a. It does not require vernalization and has a short growth cycle, but has poor ergot resistance.

[0024] The results of the early flowering period survey showed that Nanhuai Wheat 191 bloomed earlier, about 10 days earlier than L2128. In October, the parents Nanhuai Wheat 191 and L2128 were planted in the field. Nanhuai Wheat 191 was sown in 4 batches, with an interval of about 1 week between each batch.

[0025] During the flowering period of wheat, hybridization is performed using Nanhuai Wheat 191 as the female parent and L2128 as the male parent, or Nanhuai Wheat 191 as the male parent and L2128 as the female parent.

[0026] The subsequent work is to hybridize with the parent L2128. The population size needs to be around 30, with a total of 2 hybrid ears. Each emasculated ear must have at least 20 spikelets to obtain about 40 hybrid grains.

[0027] In June of the first year, hybrid ears are harvested when the wheat matures and threshed manually.

[0028] Step 2: Backcross F1 and L2128 in the culture room to obtain BC1F1

[0029] Step 1 can produce 40 F1 seeds, and about 36 of them will survive in the end.

[0030] The hybrid seeds (F1) obtained in step 1 and an appropriate amount of the parent L2128 were germinated at room temperature (25°C). The germinated seeds (seed root length of about 1 cm) were directly sown into a 30 cm diameter and 20 cm high seedling pot containing a substrate without vernalization treatment. Six seeds of each material were sown in each pot and placed in a culture room at 25°C, 22 hours of light per day, a light intensity greater than or equal to 600 Lux, and a humidity of 60-70%. Pay attention to watering during the growth period. With F1 as the female parent and L2128 as the male parent, in order to construct a BC1F1 population for genotype screening, the population number is about 200, the number of hybrid ears is at least 10, and at least 20 spikelets are guaranteed in each emasculated ear. The hybrid ears are harvested about 20-25 days after artificial pollination, when the grains are green to a certain extent. The harvested ears are placed in a drying room at 55°C for 10-12 hours and threshed manually to obtain the progeny BC1F1. This step takes a total of 2 months, during which time pay attention to pests and diseases such as aphids and powdery mildew.

[0031] Step 3: Select the BC1F1 generation with the target trait and backcross it with L2128 in the culture room

[0032] In step 2, about 200 BC1F1 seeds were obtained, and about 180 plants survived in the end.

[0033] In August of the first year, the BC1F1 grains obtained in step 2 and an appropriate amount of the parent L2128 are planted in the culture room; the planting method and culture conditions are the same as step 2; the DNA of the BC1F1 is extracted from the wheat at the three-leaf stage, and the BC1F1 plants homozygous for the Vrn-A1a gene and carrying the ergot resistance gene are selected, and the plants with a short heading period and good agronomic traits are marked with a card. According to the ratio of Vrn-A1a / Vrn-A1a:Vrn-A1a / vrn-1=1:1 in BC1F1, about 90 plants homozygous for the Vrn-A1a genotype can be obtained, and then according to the SSR marker of the ergot resistance gene Fhb-1, according to the ratio of Fhb-1 / fhb-1:fhb-1 / fhb-1=1:1, the plants heterozygous for the Fhb-1 gene are selected, and about 45 plants can be obtained. Following the same hybridization and planting method as in step 2, the BC1F1 plants that meet the requirements are hybridized with L2128, and the hybrid ears are harvested about 20-25 days after artificial pollination; the offspring BC2F1 that does not require vernalization, has a short heading period and carries the Fhb-1 gene is obtained.

[0034] Step 4: Continuous backcross selection of BC2F1 and L2128 in the growth chamber to obtain the target material

[0035] According to the genotype and phenotype identification method of the BC1F1 population in step 3, after obtaining BC2F1, the same method is used to obtain BC3F1, BC4F1, ...; each generation takes about 2 months, 6 generations can be obtained in a year, and the offspring BC5F1 can be obtained in April of the second year. The BC5F1 generation has met the basic requirements of L2128 as a genetic background. In the culture room, BC5F1 is self-pollinated for one generation, and according to the planting and screening method of step 2, according to the ratio of Fhb-1 / Fhb-1: Fhb-1 / fhb-1: fhb-1 / fhb-1=1:2:1, 10 target materials with L2128 genetic background homozygous that do not require vernalization, have a short heading period, can safely overwinter, and carry the Fhb-1 ergot resistance gene are finally obtained in June of the second year. Single ears are harvested, dried separately, and threshed manually, which can be used for other breeding research.

[0036] The above is only a preferred implementation of this patent. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of this patent. These improvements and substitutions should also be regarded as the scope of protection of this patent.

Claims

1. A method for rapid breeding of short growth cycle materials, characterized in that The following steps are involved: (1) Select parent material A carrying the target trait and hybridize it with short-growing wheat germplasm L2128, which carries the Vrn-A1a gene and does not require vernalization; (2) backcrossing the F1 generation obtained in step (1) with L2128 in a culture room to obtain BC1F1, with culture conditions of 25°C, 22 hours of light per day, and 60-70% humidity for 2 months; (3) Perform genotypic and phenotypic screening on the BC1F1 generation, select individual plants carrying the Vrn-A1a gene and the target trait, and continuously backcross with L2128 to obtain BC2F1 to BC5F1 generations, with each generation taking 2 months; (4) Self-pollinating BC5F1 and selecting stable materials that are homozygous for the L2128 genetic background and carry the target trait; The culture room is planted in a seedling pot with a diameter of 30 cm and a height of 20 cm, 6 germinated seeds are sown in each pot, and the light intensity is ≥600 Lux; each hybrid ear in step (1) and step (2) is guaranteed to have at least 20 spikelets, and the number of hybrid ears is ≥2 and ≥10 respectively.

2. Application of the method according to claim 1 in rapidly constructing a wheat genetic population.

3. Use of the method according to claim 1 in shortening the research cycle of gene localization or map-based cloning.

4. Application of the method according to claim 1 in developing molecular marker-assisted selection breeding technology.

5. Use of the method according to claim 1 in breeding disease-resistant, stress-resistant or high-quality hybrid wheat varieties.

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