A method for breeding herbicide-resistant corn

Abstract

This invention provides a method for breeding herbicide-resistant millet, belonging to the field of millet breeding technology. The breeding method includes: using Jinxuan 6 millet as the female parent and Jigu 22 as the male parent, hybridizing to obtain F1 generation seeds; selecting F1 generation seeds with excellent agronomic traits, soaking them sequentially in water and seed soaking solution to obtain pretreated seeds; culturing the pretreated seeds in a seedling substrate to obtain seedlings; transplanting the seedlings, spraying with clethodim when the seedlings reach the 3-5 leaf stage and 7-8 leaf stage, and dark-treating the millet ears at the milk stage and waxy stage respectively, harvesting F2 generation seeds, repeating the planting of the next generation seeds and spraying with clethodim to screen for stable inheritance and excellent agronomic traits in F6 generation seeds. Studies show that the millet bred by this invention has a survival rate of up to 90% under herbicide stress, and the incidence of millet leaf spot disease is only 6.67%.

Description

Technical Field

[0001] This invention belongs to the field of millet breeding technology, and particularly relates to a method for breeding herbicide-resistant millet. Background Technology

[0002] Millet (Setaria italica), a plant belonging to the Poaceae family, is an annual herb with stout stems, few tillers, and narrow, lanceolate leaves with prominent midribs and veinlets, covered in fine hairs. It has spike-like panicles, 20–30 cm long, with spikelets clustered on tertiary peduncles, each spikelet generally covered in bristles. Each spike contains hundreds to thousands of tiny grains, about 0.1 cm in diameter. The spike is typically golden yellow when mature, with small, mostly yellow, oval grains. After hulling, it is commonly known as millet. The husks of foxtail millet come in various colors, including white, red, yellow, black, orange, and purple, hence the saying "millet has five colors." It is widely cultivated in temperate and tropical regions of Eurasia.

[0003] Most millet varieties are not resistant to herbicides and cannot be controlled with herbicides. Therefore, manual weeding is required during millet cultivation, increasing management costs, reducing yield, and hindering the industrialization of millet farming. Furthermore, millet growth is regionally specific; the same variety can exhibit different growth performances in different areas. Currently, only a limited number of herbicide-resistant millet varieties are available. Therefore, it is essential to provide a new herbicide-resistant millet germplasm resource to offer growers a new seed selection, thereby improving millet yield and nutritional value. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for breeding herbicide-resistant millet, wherein the millet obtained by the breeding has the characteristics of strong herbicide resistance, strong disease resistance and high yield.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for breeding herbicide-resistant millet, comprising the following steps:

[0007] (1) Using Jinxuan No. 6 millet as the female parent and Jigu 22 as the male parent, hybridization was carried out to obtain F1 generation seeds;

[0008] (2) Select F1 generation seeds with excellent agronomic traits and soak them in water and seed soaking solution in turn to obtain pretreated seeds;

[0009] (3) The pretreated seeds are placed in a seedling substrate for cultivation to obtain seedlings;

[0010] (4) Transplant seedlings, and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and the 7-8 leaf stage. Dark treatment is carried out on the ears of grain at the milk stage and the waxy stage, respectively, and F2 generation seeds are harvested.

[0011] (5) Plant F2 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and the 7-8 leaf stage to select plants with excellent agronomic traits and harvest F3 generation seeds.

[0012] (6) Repeat step (5) to harvest F6 generation seeds.

[0013] Preferably, the excellent agronomic traits are: plant height 130±10cm, main stem diameter 0.3~0.5cm, main ear length 25~30cm, single ear weight 15~25g, upright stem, uniform and compact ear stacks, and spindle-shaped ear.

[0014] Preferably, the soaking time in the water in step (2) is 2-3 hours; the soaking solution uses phosphate buffer as a solvent and contains 0.5-0.8 mM / L NaN3 and 20-30 mM / L ethyl methanesulfonate; the soaking time in the soaking solution is 3-5 hours.

[0015] Preferably, the soaking temperature is 20-25°C, and after soaking, the seeds are washed with 0.1-0.2 mol / L NaS2SO3 solution, the washing is performed 2-3 times, and the washing frequency is 10-15 min / time.

[0016] Preferably, the seedling substrate in step (3) comprises the following raw materials in parts by weight:

[0017] 15-20 parts coconut shell, 10-20 parts earthworm castings, 5-8 parts vermiculite, 50-80 parts humus, 0.2-0.5 parts indolebutyric acid, 0.2-0.5 parts naphthaleneacetic acid, 0.005-0.008 parts NaN, and 0.2-0.3 parts ethyl methanesulfonate.

[0018] Preferably, the culture temperature in step (3) is 20±3℃, and the culture time is 5 to 7 days.

[0019] Preferably, the plant spacing in step (4) is 2-3 cm and the row spacing is 35-40 cm.

[0020] Preferably, the mass percentage of clethodim in step (4) is 20±5%, and the application rate of clethodim at the 3-5 leaf stage is 1-2 L / hm. 2 The application rate of chlorpyrifos during the 7-8 leaf stage is 1.5-2.0 L / hm². 2 .

[0021] Preferably, the dark treatment method in step (4) is to soak the ears of grain in a mixed solution containing NaN3 and ethyl methanesulfonate for 15-30 seconds in the dark, wherein the concentration of NaN3 is 0.5-0.8 mM / L and the concentration of ethyl methanesulfonate is 20-30 mM / L.

[0022] Preferably, the frequency of the dark processing is 1 to 2 times / day, and the duration of the dark processing is 2 to 3 days.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention obtains herbicide-resistant, high-yielding, and disease-resistant seeds by hybridizing Jinxuan 6 millet as the female parent and Jigu 22 as the male parent, treating the F1 seeds obtained from the hybridization with NaN3 and ethyl methanesulfonate, cultivating them in a specific seedling substrate, and subjecting the millet ears to dark treatment. Studies show that under herbicide stress, the survival rate of the millet seeds bred by this invention can reach up to 90%, and the incidence of millet leaf spot disease is only 6.67%. Detailed Implementation

[0025] This invention provides a method for breeding herbicide-resistant millet, comprising the following steps:

[0026] (1) Using Jinxuan No. 6 millet as the female parent and Jigu 22 as the male parent, hybridization was carried out to obtain F1 generation seeds;

[0027] (2) Select F1 generation seeds with excellent agronomic traits and soak them in water and seed soaking solution in turn to obtain pretreated seeds;

[0028] (3) The pretreated seeds are placed in a seedling substrate for cultivation to obtain seedlings;

[0029] (4) Transplant seedlings, and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and the 7-8 leaf stage. Dark treatment is carried out on the ears of grain at the milk stage and the waxy stage, respectively, and F2 generation seeds are harvested.

[0030] (5) Plant F2 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and the 7-8 leaf stage to select plants with excellent agronomic traits and harvest F3 generation seeds.

[0031] (6) Repeat step (5) to harvest F6 generation seeds.

[0032] In this invention, Jinxuan 6 millet is used as the female parent and Jigu 22 is used as the male parent to hybridize and obtain F1 generation seeds. F1 generation seeds with excellent agronomic traits are selected and soaked in water and seed soaking solution in sequence to obtain pretreated seeds.

[0033] In this invention, the preferred agronomic traits are: plant height 130±10cm, main stem diameter 0.3-0.5cm, main ear length 25-30cm, single ear weight 15-25g, upright stem, uniform and compact ear distribution, and spindle-shaped ear. More preferably, the plant height 130±8cm, main stem diameter 0.35-0.45cm, main ear length 26-28cm, single ear weight 16-24g, upright stem, uniform and compact ear distribution, and spindle-shaped ear. Even more preferably, the plant height 130±5cm, main stem diameter 0.4cm, main ear length 27cm, single ear weight 18-22g, upright stem, uniform and compact ear distribution, and spindle-shaped ear. The soaking time in water is preferably 2-3 hours, more preferably 2.2-2.8 hours, and even more preferably 2.4-2.6 hours; the soaking solution is preferably a phosphate buffer solution containing 0.5-0.8 mM / L NaN3 and 20-30 mM / L ethyl methanesulfonate, more preferably a phosphate buffer solution containing 0.6-0.7 mM / L NaN3 and 22-28 mM / L ethyl methanesulfonate, and even more preferably a phosphate buffer solution containing 0.65 mM / L NaN3 and 24-26 mM / L ethyl methanesulfonate; the soaking time in the soaking solution... The soaking time is preferably 3-5 hours, more preferably 3.5-4.5 hours, and even more preferably 4 hours; the molar concentration of the phosphate buffer is preferably 0.10-0.15 mol / L, more preferably 0.12-0.14 mol / L, and even more preferably 0.13 mol / L; the pH of the phosphate buffer is preferably 6.86-7.0, more preferably 6.87-6.88; the soaking temperature is preferably 20-25℃, more preferably 21-24℃, and even more preferably 22-23℃; the soaking is preferably performed under light-protected conditions using a shaker. The seeds are preferably washed with a 0.1–0.2 mol / L NaS₂SO₃ solution, more preferably with a 0.12–0.18 mol / L NaS₂SO₃ solution, and even more preferably with a 0.14–0.16 mol / L NaS₂SO₃ solution. The number of washes is preferably 2–3 times. The washing frequency is preferably 10–15 min / wash, more preferably 12–14 min / wash, and even more preferably 13 min / wash. After washing with NaS₂SO₃ solution, the seeds are preferably rinsed with water 3–4 times and the surface moisture is dried.

[0034] In this invention, pretreated seeds are placed in a seedling substrate for cultivation to obtain seedlings.

[0035] In this invention, the seedling substrate preferably comprises the following raw materials in parts by weight:

[0036] 15-20 parts coconut shell, 10-20 parts earthworm castings, 5-8 parts vermiculite, 50-80 parts humus, 0.2-0.5 parts indolebutyric acid, 0.2-0.5 parts naphthaleneacetic acid, 0.005-0.008 parts NaN, and 0.2-0.3 parts ethyl methanesulfonate.

[0037] In this invention, the seedling substrate comprises 15-20 parts coconut husk, preferably 16-18 parts, more preferably 17 parts; the seedling substrate comprises 10-20 parts earthworm castings, preferably 12-18 parts, more preferably 14-16 parts; the seedling substrate comprises 5-8 parts vermiculite, preferably 6-7 parts; the seedling substrate comprises 50-80 parts humus, preferably 55-75 parts, more preferably 60-70 parts, and even more preferably 65 parts; the seedling substrate comprises 0.2-0.5 parts indolebutyric acid, preferably 0.3-0.4 parts, more preferably 0.35 parts; the seedling substrate comprises 0.2-0.5 parts naphthaleneacetic acid, preferably 0.3-0.4 parts, more preferably 0.35 parts; the seedling substrate comprises N... The substrate contains 0.005–0.008 parts of NaN3, preferably 0.006–0.007 parts; the seedling substrate includes 0.2–0.3 parts of ethyl methanesulfonate, preferably 0.22–0.28 parts, and more preferably 0.24–0.26 parts; the coconut husk, earthworm castings, vermiculite, and humus in the seedling substrate can provide a good growth environment for millet seeds, providing essential nutrients and trace elements for the growth and development of millet. At the same time, the use of indolebutyric acid and naphthaleneacetic acid can promote the growth of millet seeds and accelerate the seedling speed. Furthermore, the addition of NaN3 and ethyl methanesulfonate can induce the normal synthesis of DNA in millet during its growth and development, thereby achieving a mutation effect and obtaining seeds with strong herbicide resistance.

[0038] In this invention, the culture temperature is preferably 20±3℃, more preferably 20±2℃, and even more preferably 20±1℃; the culture time is preferably 5-7 days, and more preferably 6 days.

[0039] In this invention, seedlings are transplanted, and when the seedlings grow to the 3-5 leaf stage and the 7-8 leaf stage, chlorpyrifos is sprayed. The ears of grain are then subjected to dark treatment at the milk stage and the waxy stage, respectively, and F2 generation seeds are harvested.

[0040] In this invention, the plant spacing during transplanting is preferably 2-3 cm, more preferably 2.2-2.8 cm, and even more preferably 2.4-2.6 cm; the row spacing is preferably 35-40 cm, more preferably 36-38 cm, and even more preferably 37 cm; the mass percentage content of the chloroquine is preferably 20±5%, more preferably 20±4%, and even more preferably 20±2%; the application rate of chloroquine at the 3-5 leaf stage is preferably 1-2 L / hm. 2 More preferably, it is 1.2–1.8 L / hm. 2 More preferably, it is 1.4–1.6 L / hm. 2 The optimal application rate of tebufenozide at the 7-8 leaf stage is 1.5-2.0 L / hm². 2 More preferably, it is 1.6–1.8 L / hm. 2 A further preferred value is 1.7 L / hm. 2 The preferred method for dark treatment is to soak the ears of grain in a mixed solution containing NaN3 and ethyl methanesulfonate for 15–30 seconds, more preferably 20–25 seconds, and even more preferably 22–24 seconds, in the dark. The concentration of NaN3 is preferably 0.5–0.8 mM / L, more preferably 0.6–0.7 mM / L, and even more preferably 0.65 mM / L. The concentration of ethyl methanesulfonate is preferably 20–30 mM / L, more preferably 22–28 mM / L, and even more preferably 24–26 mM / L. The frequency of dark treatment is preferably 1–2 times / day, and the duration of dark treatment is preferably 2–3 days.

[0041] In this invention, F2 generation seeds are planted in the field, and chlorpyrifos is sprayed when the seedlings grow to the 3-5 leaf stage and the 7-8 leaf stage. Plants with excellent agronomic traits are selected and F3 generation seeds are harvested. The above steps are repeated to harvest F6 generation seeds.

[0042] In this invention, the preferred agronomic traits are: plant height 130±10cm, main stem diameter 0.3-0.5cm, main ear length 25-30cm, single ear weight 15-25g, upright stem, uniform and compact ear distribution, and spindle-shaped ear. More preferably, the plant height is 130±8cm, main stem diameter 0.35-0.45cm, main ear length 26-28cm, single ear weight 16-24g, upright stem, uniform and compact ear distribution, and spindle-shaped ear. Even more preferably, the plant height is 130±5cm, main stem diameter 0.4cm, main ear length 27cm, single ear weight 18-22g, upright stem, uniform and compact ear distribution, and spindle-shaped ear. The purpose of repeatedly planting the next generation of seeds is to screen for herbicide-resistant seeds with stable heritability and excellent agronomic traits.

[0043] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] A method for breeding herbicide-resistant millet, comprising the following steps:

[0046] (1) Using Jinxuan No. 6 millet (self-bred by Taian Academy of Agricultural Sciences) as the female parent and Jigu 22 (bred by the Millet Research Institute of Hebei Academy of Agricultural and Forestry Sciences) as the male parent, hybridization was carried out to obtain F1 generation seeds;

[0047] (2) Select F1 generation seeds with a plant height of 130±5cm, main stem diameter of 0.4cm, main spike length of 27cm, single spike weight of 18-22g, upright stem, uniform and compact spike packing, and spindle-shaped spike. Soak the seeds in water at 22℃ for 2.5h, then place them in a seed soaking solution (using phosphate buffer (0.1mol / L, pH7.0) as solvent, containing 0.65mM / L NaN3 and 25mM / L ethyl methanesulfonate) and shake them on a shaker for 4h under dark conditions. Wash them twice with 0.15mol / L NaS2SO3 solution for 13min each time. After washing, rinse them three times with running water and dry the surface of the seeds to obtain pretreated seeds.

[0048] (3) Place the pretreated seeds in the seedling substrate and culture them at 20±1℃ for 6 days to obtain seedlings;

[0049] (4) Transplant seedlings with a plant spacing of 2.5 cm and a row spacing of 37 cm. When the seedlings grow to the 3-5 leaf stage, apply 1.5 L / hm² of fertilizer. 2 Spray with 20±2% chlorothalonil at a rate of 1.7 L / hm² during the 7-8 leaf stage. 2 Spray with 20±2% tebufenozide by mass, and soak the ears of grain for 23 seconds in a mixed solution containing NaN3 and ethyl methanesulfonate (the concentration of NaN3 in the mixed solution is 0.65 mM / L and the concentration of ethyl methanesulfonate is 25 mM / L) in the dark at the milk stage and waxy stage, respectively. Soak once a day for 2 days, and harvest F2 generation seeds.

[0050] (5) Plant F2 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±5cm, main stem diameter of 0.4cm, main ear length of 27cm, single ear weight of 18-22g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F3 generation seeds.

[0051] (6) Plant F3 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±5cm, main stem diameter of 0.4cm, main ear length of 27cm, single ear weight of 18-22g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F4 generation seeds.

[0052] (7) Plant F4 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±5cm, main stem diameter of 0.4cm, main ear length of 27cm, single ear weight of 18-22g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F5 generation seeds.

[0053] (8) Plant F5 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±5cm, main stem diameter of 0.4cm, main ear length of 27cm, single ear weight of 18-22g, upright stem, uniform and compact ear packing, and spindle-shaped ear shape, and harvest F6 generation seeds.

[0054] The formula for the seedling substrate is as follows: 17 parts coconut shell, 15 parts earthworm castings, 7 parts vermiculite, 65 parts humus, 0.35 parts indolebutyric acid, 0.35 parts naphthaleneacetic acid, 0.007 parts NaN3, and 0.25 parts ethyl methanesulfonate.

[0055] Example 2

[0056] A method for breeding herbicide-resistant millet, comprising the following steps:

[0057] (1) Using Jinxuan No. 6 millet (self-bred by Taian Academy of Agricultural Sciences) as the female parent and Jigu 22 (bred by the Millet Research Institute of Hebei Academy of Agricultural and Forestry Sciences) as the male parent, hybridization was carried out to obtain F1 generation seeds;

[0058] (2) Select F1 generation seeds with a plant height of 130±10cm, main stem diameter of 0.3cm, main spike length of 25cm, single spike weight of 15g, upright stem, uniform and compact spike packing, and spindle-shaped spike. Soak the seeds in water at 20℃ for 2h, then place them in a seed soaking solution (using phosphate buffer (0.1mol / L, pH7.0) as solvent, containing 0.5mM / L NaN3 and 20mM / L ethyl methanesulfonate) and shake them on a shaker for 3h under dark conditions. Wash them twice with 0.1mol / L NaS2SO3 solution for 15min each time. After washing, rinse them four times with running water and dry the surface of the seeds to obtain pretreated seeds.

[0059] (3) Place the pretreated seeds in the seedling substrate and culture them at 20±2℃ for 7 days to obtain seedlings;

[0060] (4) Transplant seedlings with a plant spacing of 2cm and a row spacing of 35cm. When the seedlings grow to the 3-5 leaf stage, apply 1L / hm 2 Spray with 20±1% tebuconazole at a rate of 1.5 L / hm² during the 7-8 leaf stage. 2 Spray 20±1% tebufenozide and soak the ears of grain in a mixed solution containing NaN3 and ethyl methanesulfonate (the concentration of NaN3 in the mixed solution is 0.5 mM / L and the concentration of ethyl methanesulfonate is 20 mM / L) for 30 seconds in the dark at the milk stage and waxy stage, respectively. Soak once a day for 3 days, and harvest F2 generation seeds.

[0061] (5) Plant F2 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±10cm, main stem diameter of 0.3cm, main ear length of 25cm, single ear weight of 15g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F3 generation seeds.

[0062] (6) Plant F3 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±10cm, main stem diameter of 0.3cm, main ear length of 25cm, single ear weight of 15g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F4 generation seeds.

[0063] (7) Plant F4 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±10cm, main stem diameter of 0.3cm, main ear length of 25cm, single ear weight of 15g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F5 generation seeds.

[0064] (8) Plant F5 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±10cm, main stem diameter of 0.3cm, main ear length of 25cm, single ear weight of 15g, upright stem, uniform and compact ear packing, and spindle-shaped ear shape, and harvest F6 generation seeds.

[0065] The formula for the seedling substrate is as follows: 15 parts coconut shell, 10 parts earthworm castings, 8 parts vermiculite, 80 parts humus, 0.5 parts indolebutyric acid, 0.2 parts naphthaleneacetic acid, 0.005 parts NaN3, and 0.2 parts ethyl methanesulfonate.

[0066] Example 3

[0067] A method for breeding herbicide-resistant millet, comprising the following steps:

[0068] (1) Using Jinxuan No. 6 millet (self-bred by Taian Academy of Agricultural Sciences) as the female parent and Jigu 22 (bred by the Millet Research Institute of Hebei Academy of Agricultural and Forestry Sciences) as the male parent, hybridization was carried out to obtain F1 generation seeds;

[0069] (2) Select F1 generation seeds with a plant height of 130±3cm, main stem diameter of 0.5cm, main spike length of 30cm, single spike weight of 25g, upright stem, uniform and compact spike packing, and spindle-shaped spike. Soak the seeds in water at 25℃ for 3h, then place them in a seed soaking solution (using phosphate buffer (0.1mol / L, pH7.0) as solvent, containing 0.8mM / L NaN3 and 30mM / L ethyl methanesulfonate) and shake them on a shaker for 5h under dark conditions. Wash them three times with 0.2mol / L NaS2SO3 solution for 10min each time. After washing, rinse them three times with running water and dry the surface of the seeds to obtain pretreated seeds.

[0070] (3) Place the pretreated seeds in the seedling substrate and culture them at 20±1℃ for 5 days to obtain seedlings;

[0071] (4) Transplant seedlings with a plant spacing of 3cm and a row spacing of 40cm. When the seedlings grow to the 3-5 leaf stage, apply 2L / hm 2 Spray with 20±5% tebuconazole at a rate of 2.0 L / hm² during the 7-8 leaf stage. 2 Spray 20±5% tebufenozide and soak the ears of grain for 15 seconds in a mixed solution containing NaN3 and ethyl methanesulfonate (the concentration of NaN3 in the mixed solution is 0.8 mM / L and the concentration of ethyl methanesulfonate is 30 mM / L) in the dark during the milk stage and waxy stage, respectively. Soak the ears twice a day for 2 days and harvest the F2 generation seeds.

[0072] (5) Plant F2 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±3cm, main stem diameter of 0.5cm, main ear length of 30cm, single ear weight of 25g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F3 generation seeds.

[0073] (6) Plant F3 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±3cm, main stem diameter of 0.5cm, main ear length of 30cm, single ear weight of 25g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F4 generation seeds.

[0074] (7) Plant F4 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±3cm, main stem diameter of 0.5cm, main ear length of 30cm, single ear weight of 25g, upright stem, uniform and compact ear stacks, and spindle-shaped ear shape, and harvest F5 generation seeds.

[0075] (8) Plant F5 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Select plants with a plant height of 130±3cm, main stem diameter of 0.5cm, main ear length of 30cm, single ear weight of 25g, upright stem, uniform and compact ear packing, and spindle-shaped ear shape, and harvest F6 generation seeds.

[0076] The formula for the seedling substrate is as follows: 20 parts coconut shell, 20 parts earthworm castings, 5 parts vermiculite, 50 parts humus, 0.2 parts indolebutyric acid, 0.2 parts naphthaleneacetic acid, 0.008 parts NaN3, and 0.3 parts ethyl methanesulfonate.

[0077] Comparative Example 1

[0078] Herbicide-resistant millet was bred using the method described in Example 1, with the only difference being that the concentration of NaN3 in the seed soaking solution was changed to 1.0 mM / L.

[0079] Comparative Example 2

[0080] The method in Example 1 was used to select herbicide-resistant millet, with the only difference being that the concentration of ethyl methanesulfonate in the seed soaking solution was changed to 50 mM / L.

[0081] Comparative Example 3

[0082] The method in Example 1 was used to select herbicide-resistant millet, with the only difference being that the millet ears were soaked in a mixed solution containing NaN3 and ethyl methanesulfonate under light.

[0083] Experimental Example 1

[0084] Dilute quizalofop-P-ethyl solutions with mass concentrations of 0.1%, 0.3%, 0.5%, and 1.0% were prepared. Two thousand healthy, plump seeds from Examples 1 and Comparative Examples 1-3 were selected and soaked in different concentrations of dilute quizalofop-P-ethyl solutions. Seeds soaked for 10, 20, 30, 40, 50, and 60 minutes were collected as samples, dried, and then placed in petri dishes containing a 0.5 cm thick, fully water-soaked sponge for germination. Germination time was 4–5 days. The number of seeds that grew normally in the later stages was recorded, and the survival rate was calculated. A blank control group (CK) was also established, in which water was used instead of dilute quizalofop-P-ethyl solution for seed soaking. The results are shown in Table 1.

[0085] Table 1. Seed survival rate of different treatment groups

[0086]

[0087] As shown in Table 1, the millet bred by this invention still has a good survival rate under herbicide stress, with a maximum survival rate of 90%. Moreover, in different concentrations of herbicide solutions, the survival rate of the seeds bred in Example 1 is significantly higher than that of the comparative example, indicating that the method provided by this invention can improve the survival rate of seeds under herbicide stress, that is, the method can improve the resistance of millet to herbicides.

[0088] Experimental Example 2

[0089] The following experiments were conducted at the experimental base of the Taian Academy of Agricultural Sciences:

[0090] Prepare the land 15 days before sowing, and apply 15 cubic meters of chicken manure. 3 / hm 2 Nitrogen-phosphorus-potassium compound fertilizer (15-15-15, purchased from Hebei Danong Fertilizer Co., Ltd.) 20kg / m³ 2 According to the area of ​​the community, 15m 2 Row width 2.5m, row length 6m, row spacing 0.4m, density 40,000 plants / 667m² 2 Seeds from Examples 1 and 1-3 were sown in the same manner, with three replicates, and Yugu 18 was used as a control group. When the seedlings reached the 3-5 leaf stage, they were sprayed with a 12.5% ​​dilute quizalofop-p-ethyl solution at a concentration of 1.2-1.5 L / hm². 2 No fungicides should be sprayed during the millet's growth period. At the 6-leaf stage, jointing stage, and maturity stage, 5 points were randomly selected from each plot, with 20 plants sampled at each point. The number of diseased plants was recorded, graded, and the incidence rate was calculated. Grading was performed according to the standards in Table 2.

[0091] Table 2 Grading Standards

[0092]

[0093] The incidence rate is calculated according to formula (1).

[0094] Incidence rate (%) = Number of diseased plants (leaves, ears) / Total number of plants (leaves, ears) surveyed × 100 Formula (1);

[0095] The results are shown in Table 3.

[0096] Table 3 Results of resistance identification for different millet leaf spot diseases

[0097] Processing group Incidence rate / % resistance Example 1 6.7 Disease resistance Comparative Example 1 11.3 Disease resistance Comparative Example 2 12.0 Disease resistance Comparative Example 3 13.3 Disease resistance Yu Valley 18 15.3 Disease resistance

[0098] As shown in Table 3, the millet bred in this invention has a good control effect on leaf spot disease, with an incidence rate of 6.67%, which is significantly lower than that of other treatment groups.

[0099] Experimental Example 3

[0100] The following experiment was conducted at the Taian Academy of Agricultural Sciences:

[0101] The area was divided into plots with rows 6m long, 2.5m wide, and 0.4m apart, with 40,000 plants per 667m². 2 Millet varieties including Jinxuan 6, Example 1, and Comparative Examples 1-3 were randomly planted in a block, and chlorpyrifos was sprayed on the seedlings at the 3-5 leaf stage and the 7-8 leaf stage. Three replicates were set up. At maturity, 10 uniformly growing plants were selected from each plot, and the panicle length, plant height, thousand-grain weight, and single-pane grain weight were recorded. Yield was measured in areas with uniform growth and no missing seedlings in each plot. The results are shown in Table 4.

[0102] Table 4. Growth traits and yield of millet in different treatment groups

[0103] Processing group ear length / cm Plant height / cm 1000-grain weight / g Single ear grain weight / g <![CDATA[Yield / (kg / hm 2 )]]> Example 1 27.85 130.4 2.97 18.09 6217.5 Comparative Example 1 18.28 110.2 2.42 12.17 4529.5 Comparative Example 2 16.74 106.1 2.47 14.64 4561.0 Comparative Example 3 18.13 110.6 2.34 13.29 4610.0 Jinxuan No. 6 13.85 100.5 2.30 8.37 4497.8

[0104] As shown in Table 4, the millet in Example 1 had better spike length, plant height, thousand-grain weight, single spike grain weight, and yield than other treatment groups. Among them, the yield of millet in the control group 3 without dark treatment was significantly affected, indicating that dark treatment played a key role in millet breeding.

[0105] Test Example 4

[0106] The experiment was conducted using the method described in Example 3, but the treatment of "spraying chlorpyrifos when the seedlings reach the 3-5 leaf stage and the 7-8 leaf stage" was not performed during the planting period. The results are shown in Table 5.

[0107] Table 5. Growth traits and yield of millet in different treatment groups without herbicide application.

[0108] Processing group ear length / cm Plant height / cm 1000-grain weight / g Single ear grain weight / g <![CDATA[Yield / (kg / hm 2 )]]> Example 1 26.38 122.7 2.70 16.58 5927.2 Comparative Example 1 15.28 101.5 2.34 11.49 4352.4 Comparative Example 2 14.74 103.8 2.32 12.46 4387.6 Comparative Example 3 16.81 107.3 2.21 12.58 4405.0 Jinxuan No. 6 19.74 127.1 2.63 13.02 5640.2

[0109] As shown in Table 5, the yield of millet in Example 1 was higher than that of Jinxuan 6 when no herbicide was sprayed. Compared with Table 4, the yield of Jinxuan 6 was lower when herbicide was sprayed, while the yield of millet in Example 1 remained basically unchanged. This result shows that the seeds bred by the breeding method provided by the present invention have good herbicide resistance.

[0110] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for breeding herbicide-resistant millet, characterized in that, Includes the following steps: (1) Using Jinxuan No. 6 millet as the female parent and Jigu 22 as the male parent, hybridization was carried out to obtain F1 generation seeds; (2) Select F1 generation seeds with excellent agronomic traits and soak them in water and seed soaking solution in turn to obtain pretreated seeds; (3) Place the pretreated seeds in a seedling substrate for cultivation to obtain seedlings; (4) Transplant seedlings and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage. Dark treatment of the ears of grain is carried out at the milk stage and the waxy stage respectively, and F2 generation seeds are harvested. (5) Plant F2 generation seeds in the field and spray chlorpyrifos when the seedlings grow to the 3-5 leaf stage and 7-8 leaf stage to select plants with excellent agronomic traits and harvest F3 generation seeds; (6) Repeat step (5) to harvest F6 generation seeds; The soaking solution uses phosphate buffer as a solvent and contains 0.5-0.8 mM / L NaN3 and 20-30 mM / L ethyl methanesulfonate; the soaking time in the soaking solution is 3-5 hours. The seedling substrate described in step (3) is composed of the following raw materials in parts by weight: 15-20 parts coconut shell, 10-20 parts earthworm castings, 5-8 parts vermiculite, 50-80 parts humus, 0.2-0.5 parts indolebutyric acid, 0.2-0.5 parts naphthaleneacetic acid, 0.005-0.008 parts NaN3, 0.2-0.3 parts ethyl methanesulfonate; The dark treatment method in step (4) is to soak the ears of grain in a mixed solution containing NaN3 and ethyl methanesulfonate for 15-30 seconds in the dark. The concentration of NaN3 is 0.5-0.8 mM / L and the concentration of ethyl methanesulfonate is 20-30 mM / L. The frequency of the dark treatment is 1-2 times / day and the duration of the dark treatment is 2-3 days.

2. The breeding method according to claim 1, characterized in that, The excellent agronomic traits are: plant height 130±10cm, main stem diameter 0.3~0.5cm, main ear length 25~30cm, single ear weight 15~25g, upright stem, uniform and compact ear packing, and spindle-shaped ear.

3. The breeding method according to claim 1, characterized in that, The soaking time in water in step (2) is 2-3 hours.

4. The breeding method according to claim 1 or 3, characterized in that, The soaking temperature is 20~25℃. After soaking, the seeds are washed with 0.1~0.2mol / L NaS2SO3 solution. The number of washes is 2~3 times, and the washing frequency is 10~15min / wash.

5. The breeding method according to claim 1, characterized in that, The culture temperature in step (3) is 20±3℃, and the culture time is 5~7 days.

6. The breeding method according to claim 1, characterized in that, In step (4), the plant spacing for transplanting is 2-3 cm and the row spacing is 35-40 cm.

7. The breeding method according to claim 1, characterized in that, The mass percentage of clethodim in step (4) is 20±5%, and the application rate of clethodim at the 3-5 leaf stage is 1-2 L / hm. 2 The application rate of tebuconazole during the 7-8 leaf stage is 1.5-2.0 L / hm². 2 .

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