A millet hybrid seed production method using a precocious dwarf male parent

Abstract

The application provides a millet hybrid seed production method using a precocious dwarf male parent, and belongs to the technical field of hybrid breeding, and comprises the following steps: land preparation and ridge formation, planting a female parent under the ridge, and sowing a precocious dwarf male parent on the ridge according to the heading period of the male parent; irrigating in time after sowing the male parent, and applying nitrogen fertilizer at the seedling stage, the jointing stage and the heading stage of the male parent, and applying nitrogen fertilizer as a whole at the flowering stage; and spraying paclobutrazol and / or mepiquat chloride at the 7-leaf stage and the 1-leaf stage of the female parent. The seed production method provided by the application ensures full pollination, significantly improves seed production yield and quality, realizes millet hybrid seed production using a precocious dwarf male parent, and promotes the application of the precocious dwarf variety in production.

Description

Technical Field

[0001] This invention relates to the field of hybridization breeding technology, specifically to a method for hybridization seed production using an early-maturing, short-stalked male parent of millet. Background Technology

[0002] Millet plays a vital role in my country's agricultural production, serving as one of the country's main food crops. Millet cannot grow without water; during its development, water accounts for over 80% of the total weight of a growing millet plant. Due to restrictions on groundwater extraction and use, the emergence of early-maturing hybrid millet varieties will, to some extent, reduce groundwater consumption.

[0003] Currently, for all hybrid millet varieties, only one female parent is truly applicable: "Jizhanggu A2" (abbreviated as "A2"). Therefore, breeding ultra-early maturing hybrid varieties can only be achieved by combining an ultra-early maturing male parent with "A2". However, early-maturing male parents have short growth periods, less time for nutrient accumulation, and are generally shorter. In crop hybrid seed production, the male parent is generally required to be taller than the female parent so that the male parent's pollen can easily pollinate the female parent. Therefore, using an early-maturing, short-stemmed male parent for seed production often results in insufficient pollination, leading to low yields and making production unsuitable. Currently, there are no reported methods for breeding new dwarf hybrid millet varieties using early-maturing, short-stemmed male parents. Summary of the Invention

[0004] The purpose of this invention is to provide a method for hybrid millet seed production using an early-maturing, short-stalked male parent, thereby removing the restriction that the male parent of hybrid millet must be taller than the female parent, which is beneficial for obtaining early-maturing hybrid varieties and short-stalked hybrid varieties.

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

[0006] This invention provides a method for hybrid seed production of millet using an early-maturing, short-stalked male parent, comprising the following steps:

[0007] Prepare the land and make ridges. Plant the female parent under the ridges and sow the early-maturing, short-stalked male parent on the ridges at staggered times according to the heading period of the male parent.

[0008] Irrigate promptly after sowing the male parent, apply nitrogen fertilizer during the seedling, jointing, and heading stages of the male parent, and apply nitrogen fertilizer as a whole during the flowering stage;

[0009] Spray the parent plant with paclobutrazol and / or chlormequat chloride at the 7-leaf stage and the 1-leaf stage from the bottom.

[0010] Preferably, apply 3000-5000 kg / mu of well-rotted farmyard manure and 40-50 kg / mu of slow-release compound fertilizer before ridging.

[0011] Preferably, ridges are made every 0.9 to 1.2 meters, with a ridge width of 25 to 35 cm and a ridge height of 15 to 25 cm.

[0012] Preferably, the early-maturing, dwarf male parent is sown 20-25 days later than the female parent.

[0013] Preferably, the ratio of the number of female parent rows to the number of male parent rows is 4 to 6:2.

[0014] Preferably, the nitrogen fertilizer includes urea.

[0015] Preferably, 4-8 kg / mu of nitrogen fertilizer is applied as topdressing during the seedling stage, jointing stage, and heading stage of the male parent, and 15-20 kg / mu of nitrogen fertilizer is applied as topdressing during the flowering stage.

[0016] Preferably, the paclobutrazol has a mass-volume fraction of 15%, and is applied at a concentration of 500 times diluted with water at a rate of 20 kg / mu; the chlormequat chloride has a volume fraction of 50%, and is applied at a concentration of 130 times diluted with water at a rate of 20 kg / mu.

[0017] Preferably, the parent plant is Jizhanggu A2.

[0018] Preferably, the breeding method for the early-maturing, dwarf paternal parent includes the following steps:

[0019] 1) Using Longgu 25 as the female parent and improved Jizhanggu 1 as the male parent, hybridization was carried out to harvest F1 generation seeds and plant F2 generation plants.

[0020] 2) Starting from the F2 generation plants, the pedigree method is used to select plants up to the F5 generation, which yields the early-maturing, dwarf male parent.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention provides a method for hybrid seed production of millet using an early-maturing, dwarf male parent. By sowing the female parent under the ridges and the early-maturing male parent on the ridges, applying fertilizer and water in a biased manner, and spraying plant growth inhibitors to suppress the height of the female parent, the male parent is obtained to be more than 40 cm taller than the female parent, ensuring sufficient pollination, significantly improving seed yield and quality, realizing hybrid seed production of millet using an early-maturing, dwarf male parent, and promoting the application of early-maturing, dwarf varieties in production in cool regions. Attached Figure Description

[0023] Figure 1 A comparison image of the parent and parent lines obtained using the method described in Example 1;

[0024] Figure 2 Comparison of male and female parents obtained using conventional planting methods. Detailed Implementation

[0025] This invention provides a method for hybrid seed production of millet using an early-maturing, short-stalked male parent, comprising the following steps:

[0026] Prepare the land and make ridges. Plant the female parent under the ridges and sow the early-maturing, short-stalked male parent on the ridges at staggered times according to the heading period of the male parent.

[0027] Irrigate promptly after sowing the male parent, apply nitrogen fertilizer during the seedling, jointing, and heading stages of the male parent, and apply nitrogen fertilizer as a whole during the flowering stage;

[0028] Spray the parent plant with paclobutrazol and / or chlormequat chloride at the 7-leaf stage and the 1-leaf stage from the bottom.

[0029] In this invention, before land preparation and ridging, preferably 3000-5000 kg / mu of well-rotted farmyard manure and 40-50 kg / mu of slow-release compound fertilizer are applied. The preferred land preparation method is rotary tillage. The ridging is preferably done every 0.9-1.2 m in the seed production field, with a ridge width of 25-35 cm and a ridge height of 15-25 cm; more preferably, ridges are made every 1.0 m in the seed production field, with a ridge width of 30 cm and a ridge height of 20 cm. As one possible implementation, a drip irrigation tape is laid in the center of each ridge to facilitate watering and fertilization during staggered sowing of the male parent, thereby increasing the plant height of the male parent.

[0030] In this invention, the female parent is planted under the ridge. Preferably, the female parent is planted 15-25 cm away from the ridge, and the row spacing between female parents is 15-25 cm. As one implementation method, irrigation is carried out before planting the female parent to create soil moisture, and irrigation is carried out reasonably according to the field moisture conditions after planting. This invention sows early-maturing, short-stalked male parents on the ridge at staggered times according to the heading period of the male parent. Based on the difference in growth period between the male and female parents, the early-maturing male parent is sown 20-25 days later than the female parent. Preferably, the male parent is planted 4-6 cm away from the edge of the ridge, and the row spacing between male parents is 15-25 cm. Since the male parent is sown more than 20 days later than the female parent, the soil moisture is poor when sowing the male parent, so the male parent should be irrigated in time after sowing to promote growth; while at this time, the female parent is in the seedling stage and needs to be drought-treated to reduce the plant height difference between the male and female parents. As an optional implementation method, the ratio of the number of female parent rows to the number of male parent rows is preferably 4 to 6:2, and more preferably 4 to 5:2.

[0031] In this invention, nitrogen fertilizer is applied as topdressing during the seedling, jointing, and heading stages of the male parent, and as a whole-plant topdressing during the flowering stage. Preferably, 4-8 kg of urea is applied during irrigation at the seedling, jointing, and heading stages of the male parent, and 15-20 kg of urea is applied during irrigation at the flowering stage. This invention significantly increases the height of the male parent by applying more fertilizer and irrigation through this method of concentrated fertilization and irrigation.

[0032] In this invention, the female parent plant is sprayed with paclobutrazol and / or chlormequat chloride at the 7-leaf stage and the top 1-leaf stage. The preferred volume fraction of paclobutrazol is 15%, diluted 500 times with water and sprayed at 20 kg / mu; the preferred volume fraction of chlormequat chloride is 50%, diluted 130 times with water and sprayed at 20 kg / mu. This invention, by spraying the female parent plant with paclobutrazol and / or chlormequat chloride at the 7-leaf stage and the top 1-leaf stage, delays plant growth, inhibits stem elongation, and shortens the plant height. Simultaneously, it increases the plant's stress resistance and lodging resistance, thereby effectively reducing the height of the female parent plant and increasing the yield of the hybrid. This invention also includes timely harvesting after maturity, which avoids losses caused by withered and fallen grains.

[0033] In this invention, the maternal parent is preferably Jizhanggu A2, and the breeding method of the paternal parent preferably includes the following steps:

[0034] 1) Using Longgu 25 as the female parent and improved Jizhanggu 1 as the male parent, hybridization was carried out to harvest F1 generation seeds and plant F2 generation plants.

[0035] 2) Starting from the F2 generation plants, the pedigree method is used to select plants up to the F5 generation, which yields the early-maturing, dwarf male parent.

[0036] In this invention, the breeding method for the early-maturing, dwarf paternal parent more preferably includes the following steps:

[0037] 1) Using Longgu 25 as the female parent and improved Jizhanggu 1 as the male parent, artificial emasculation hybridization was carried out to harvest F1 generation seeds and plant F2 generation plants.

[0038] 2) Starting from the F2 generation plants, the pedigree method is used to continuously select early-maturing dwarf plants with excellent agronomic traits from the superior strain population from which early-maturing dwarf individual plants are isolated, and thus obtain the F3 generation plants.

[0039] 3) Plant F3 generation plants, and continuously select early-maturing dwarf plants with excellent agronomic traits from the superior strain population from which early-maturing dwarf individual plants are isolated to obtain F4 generation plants.

[0040] 4) Plant F4 generation plants, and continuously select early-maturing dwarf plants with excellent agronomic traits from the superior strain population from which early-maturing dwarf individual plants are isolated, thus obtaining the early-maturing dwarf male parent.

[0041] In this invention, steps 2) to 4) employ a pedigree method to continuously select early-maturing, dwarf plants with superior agronomic traits from a population of superior strains from which early-maturing, dwarf individual plants have been isolated, including the following steps:

[0042] S1: Plant 500-1500 plants from the F2-F4 segregating generations;

[0043] S2: Select plants that are early-maturing, have stable yields, good plant and leaf morphology, and are resistant to disease and cold.

[0044] In this invention, plants that are early-maturing, have stable yields, good plant and leaf morphology, and good cold resistance are selected. The early-maturing plants are preferably those with a heading period of less than 50 days. The stable yields are preferably those with a yield of more than 400 kg per mu. The good plant and leaf morphology is preferably those with compact ear type and neat branches.

[0045] In this invention, unless otherwise specified, well-rotted farmyard manure, ternary slow-release compound fertilizer, paclobutrazol, chlormequat chloride, urea, or Longgu 25 are all commercially available products well known to those skilled in the art.

[0046] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0047] Example 1

[0048] This embodiment describes a method for hybrid seed production using an early-maturing, short-stalked male parent in millet. The specific steps are as follows:

[0049] (1) Selecting parental lines

[0050] Parent parent: Jizhanggu A2 (abbreviated as A2)

[0051] The selection method for early-maturing, dwarf paternal lines is as follows:

[0052] 1) From May to October 2016, artificial emasculation hybridization was carried out at the Zhangjiakou experimental base in Hebei Province using the early-maturing Heilongjiang resource "Longgu 25" as the female parent and "improved Jizhanggu 1" as the male parent. F1 generation was planted and F1 generation seeds were harvested.

[0053] 2) From November 2016 to March 2017, F1 generation was planted at the experimental base in Ledong Li Autonomous County, Hainan Province. After maturity, the ears were harvested and threshed together to obtain F2 generation seeds. From May 2017 to October 2017, 55 square meters of F2 generation segregating population was planted at the experimental base in Zhangjiakou, Hebei Province. 588 single ears with early maturity traits were harvested and threshed separately for each ear.

[0054] 3) From November 2017 to March 2018, F3 generation was planted at the experimental base in Ledong Li Autonomous County, Hainan Province. The ears were planted in rows, with two rows per ear, a row spacing of 25 cm, a row length of 2 m, and a plant spacing of 8 cm. 1100 early-maturing and disease-resistant ears were harvested, and each ear was threshed individually.

[0055] 4) From May to October 2018, F4 generation was planted at the experimental base in Zhangjiakou, Hebei Province. The panicles were planted in rows, with two rows for each panicle, a row spacing of 33 cm, a row length of 3 m, and a plant spacing of 12 cm. 100 panicles with good agronomic traits (i.e., heading period of less than 50 days, yield of more than 400 kg per mu, compact panicle type, neat branches and stems, and good cold resistance) were harvested. Each panicle was threshed separately to obtain the early-maturing short-stalked male parent.

[0056] 5) From November 2018 to March 2019, at the experimental base in Ledong Li Autonomous County, Hainan Province, 100 early-maturing single ears were harvested as male parents and cross-pollinated with A2 seeds using bagging. After maturity, the 100 hybrid varieties were harvested and threshed together. Five single ears were selected from each of the 100 early-maturing male parents and threshed individually.

[0057] 6) From May to October 2019, 500 early-maturing single-ear rows were planted at the experimental base in Zhangjiakou, Hebei Province. Each single ear was planted in 2 rows with a row spacing of 33 cm, a row length of 3 m, and a plant spacing of 12 cm. At the same time, early-maturing hybrid varieties were tested and bred in the Zhangjiakou Bashang area, Heilongjiang, Inner Mongolia and other frozen areas. Finally, based on the yield performance of the hybrid varieties in various regions, the "A2×1009" combination was selected as the best performing, that is, 1009 was the early-maturing dwarf male parent.

[0058] 7) From November 2019 to March 2020, small-scale seed production of "A2×1009" was carried out at the experimental base in Ledong Li Autonomous County, Hainan Province;

[0059] 8) From May to October 2020, it was planted and evaluated in frozen areas such as Zhangjiakou Bashang area, Heilongjiang, and Inner Mongolia. It performed well, with an average yield increase of more than 20% compared with the control Longgu 25.

[0060] (2) Land preparation

[0061] Combine rotary tillage with the application of 4000 kg of well-rotted farmyard manure and 45 kg of slow-release compound fertilizer per mu. In the seed production field, ridges 30 cm wide and 20 cm high are built every 1 meter, and a drip irrigation tape is laid in the center of each ridge.

[0062] (3) Sowing

[0063] The female parent is planted 20cm below the ridge, in 4 rows with a row spacing of 20cm. The male parent is planted 2 rows on the ridge, 5cm from the edge of the ridge, with a row spacing of 20cm. After irrigation, the female parent is sown first. 20 days after sowing the female parent, the first generation of male parent is sown and drip irrigated. 25 days after sowing the female parent, the second generation of male parent is sown.

[0064] (4) Irrigation and fertilization

[0065] Apply 6 kg / mu of urea during the seedling, jointing, and heading stages of the male parent, and apply 18 kg / mu of urea during the flowering stage.

[0066] (5) Inhibit the height of the mother plant

[0067] At the 7-leaf stage and the 1-leaf stage from the bottom of the parent plant, spray once with 15% paclobutrazol by weight and volume, diluted with 500 times water, at a rate of 20 kg / mu.

[0068] (6) Pollination

[0069] After the early-maturing, dwarf male parent flowers, artificial pollination can be carried out every morning when there is no dew on the flag leaf of the female parent and when the male parent's spike has misty pollen when it is gently tapped. The male parent's spike is then patted against the female parent's spike until the male parent's pollen is dissipated. The pollination period is 15 days.

[0070] (7) Harvest promptly after maturity.

[0071] The results are as follows Figure 1 As shown, the middle four rows are the female parent, and the male parent is 40 cm taller than the female parent. The female parent plant height is 0.92±0.10 meters, and the male parent plant height is 1.12±0.10 meters. When the pollen of the male parent is scattered, it is easy to pollinate the female parent, and the pollination is complete. The yield of hybrid seeds is 192 jin per mu.

[0072] Example 2

[0073] This embodiment describes a method for hybrid seed production using an early-maturing, short-stalked male parent in millet. The specific steps are as follows:

[0074] (1) Selecting parental lines

[0075] Parent parent: Jizhanggu A2 (abbreviated as A2)

[0076] Paternal parent: 1009 selected in Example 1

[0077] (2) Land preparation

[0078] Combine rotary tillage with the application of 3000 kg of well-rotted farmyard manure and 50 kg of slow-release compound fertilizer per mu. In the seed production field, ridges 25 cm wide and 15 cm high are built every 0.9 meters, and a drip irrigation tape is laid in the center of each ridge.

[0079] (3) Sowing

[0080] The female parent is planted 25cm below the ridge, in 5 rows, with a row spacing of 15cm between the female parent and the male parent is planted 2 rows on the ridge, 4cm from the edge of the ridge, with a row spacing of 15cm between the male parent and the male parent. After irrigation, the female parent is sown first, and the first batch of male parent is sown 20 days after sowing the female parent and drip irrigated. The second batch of male parent is sown 25 days after sowing the female parent.

[0081] (4) Irrigation and fertilization

[0082] During the seedling, jointing and heading stages of the male parent, apply 4 kg / mu of urea with irrigation, and during the flowering stage, apply 20 kg / mu of urea with irrigation.

[0083] (5) Inhibit the height of the mother plant

[0084] At the 7-leaf stage and the 1-leaf stage from the bottom of the mother plant, spray once with 50% chlormequat chloride, diluted with 130 times the amount of water, at a volume of 20 kg / mu.

[0085] (6) Pollination

[0086] After the early-maturing, dwarf male parent flowers, artificial pollination can be carried out every morning when there is no dew on the flag leaf of the female parent and when the male parent's spike has misty pollen when it is gently tapped. The male parent's spike is then patted against the female parent's spike until the male parent's pollen is dissipated. The pollination period is 15 days.

[0087] (7) Harvest promptly after maturity.

[0088] Example 3

[0089] This embodiment describes a method for hybrid seed production using an early-maturing, short-stalked male parent in millet. The specific steps are as follows:

[0090] (1) Selecting parental lines

[0091] Parent parent: Jizhanggu A2 (abbreviated as A2)

[0092] Paternal parent: 1009 selected in Example 1

[0093] (2) Land preparation

[0094] Combine rotary tillage with the application of 5000 kg of well-rotted farmyard manure and 40 kg of slow-release compound fertilizer per mu. In the seed production field, ridges 35 cm wide and 25 cm high are built every 1.2 meters, and a drip irrigation tape is laid in the center of each ridge.

[0095] (3) Sowing

[0096] The female parent is planted 25cm below the ridge, in 6 rows with a row spacing of 25cm. The male parent is planted 2 rows on the ridge, 6cm from the edge of the ridge, with a row spacing of 25cm. After irrigation, the female parent is sown first. 20 days after sowing the female parent, the first generation of male parent is sown and drip irrigated. 25 days after sowing the female parent, the second generation of male parent is sown.

[0097] (4) Irrigation and fertilization

[0098] During the seedling, jointing and heading stages of the male parent, apply 8 kg / mu of urea with irrigation, and during the flowering stage, apply 15 kg / mu of urea with irrigation.

[0099] (5) Inhibit the height of the mother plant

[0100] At the 7-leaf stage and the 1-leaf stage from the bottom of the mother plant, spray once with 50% chlormequat chloride, diluted with 130 times the amount of water, at a volume of 20 kg / mu.

[0101] (6) Pollination

[0102] After the early-maturing, dwarf male parent flowers, artificial pollination can be carried out every morning when there is no dew on the flag leaf of the female parent and when the male parent's spike has misty pollen when it is gently tapped. The male parent's spike is then patted against the female parent's spike until the male parent's pollen is dissipated. The pollination period is 15 days.

[0103] (7) Harvest promptly after maturity.

[0104] Comparative Example 1

[0105] This comparative example illustrates a method for millet hybridization seed production using an early-maturing, short-stalked male parent. The specific steps are as follows:

[0106] (1) Selecting parental lines

[0107] Parent parent: Jizhanggu A2 (abbreviated as A2)

[0108] Paternal parent: 1009 selected in Example 1

[0109] (2) Land preparation

[0110] Combine rotary tillage with 4000 kg of well-rotted farmyard manure and 45 kg of slow-release compound fertilizer per mu, without raising ridges or laying drip irrigation.

[0111] (3) Sowing

[0112] The female parent is planted 20cm below the ridge, in 4 rows with a row spacing of 20cm. The male parent is planted 2 rows on the ridge, 5cm from the edge of the ridge, with a row spacing of 20cm. After irrigation, the female parent is sown first. 20 days after sowing the female parent, the first batch of male parent is sown and flooded. 25 days after sowing the female parent, the second batch of male parent is sown.

[0113] (4) Irrigation and fertilization

[0114] During the male parent's jointing stage, apply 15 kg of urea per mu in conjunction with irrigation; during the heading stage, apply 15 kg of urea per mu in conjunction with irrigation.

[0115] (5) Pollination

[0116] After the early-maturing, dwarf male parent flowers, artificial pollination can be carried out every morning when there is no dew on the flag leaf of the female parent and when the male parent's spike has misty pollen when it is gently tapped. The male parent's spike is then patted against the female parent's spike until the male parent's pollen is dissipated. The pollination period is 15 days.

[0117] (6) Harvest promptly after maturity.

[0118] The results are as follows Figure 2 As shown, the middle 4 rows are the female parent. The male parent 1009 was sown late and sprouted slowly, and was shaded by the female parent seedlings, resulting in the male parent and female parent having similar plant heights, and the male parent growing very weakly. Among them, the plant height of the female parent A2 is 1.03±0.10 meters, and the plant height of the male parent is 1.01±0.10 meters, with a yield of 52 jin of hybrid seeds per mu.

[0119] By comparison, it can be seen that the millet hybrid seed production method of the present invention, which utilizes an early-maturing, dwarf male parent, significantly increases the height of the early-maturing, dwarf male parent by sowing the female parent under the ridge and the early-maturing, dwarf male parent on the ridge, applying fertilizer and water to the early-maturing, dwarf male parent, and spraying plant growth inhibitors to suppress the height of the female parent. This makes it easier for the pollen of the early-maturing, dwarf male parent to pollinate the female parent when it is scattered, resulting in complete pollination and thus significantly increasing the yield of the hybrid.

[0120] 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 hybrid seed production of millet using an early-maturing, short-stalked male parent, characterized in that, Includes the following steps: Prepare the land and make ridges. Plant the female parent under the ridges and sow the early-maturing, short-stalked male parent on the ridges at staggered times according to the heading period of the male parent. Irrigate promptly after sowing the male parent, apply nitrogen fertilizer during the seedling, jointing, and heading stages of the male parent, and apply nitrogen fertilizer as a whole during the flowering stage; Spray the female parent with paclobutrazol and / or chlormequat chloride at the 7-leaf stage and the 1-leaf stage from the bottom; Make ridges every 0.9 to 1.2 meters, with a ridge width of 25 to 35 cm and a ridge height of 15 to 25 cm; Early-maturing, dwarf male parent should be sown 20-25 days later than female parent; The nitrogen fertilizer is urea; Apply 4-8 kg / mu of nitrogen fertilizer to the male parent seedling stage, jointing stage, and heading stage respectively, and apply 15-20 kg / mu of nitrogen fertilizer as a whole during the flowering stage; The paclobutrazol has a mass-volume fraction of 15%, and is diluted 500 times with water and sprayed at a rate of 20 kg / mu; the chlormequat chloride has a volume fraction of 50%, and is diluted 130 times with water and sprayed at a rate of 20 kg / mu. The parent plant is Jizhanggu A2; The breeding method for the early-maturing, dwarf paternal parent includes the following steps: 1) Using Longgu 25 as the female parent and improved Jizhanggu 1 as the male parent, hybridization was carried out to harvest F1 generation seeds and plant F2 generation plants. 2) Starting from the F2 generation plants, the pedigree method is used to select up to the F5 generation, which yields the early-maturing dwarf male parent.

2. The seed production method according to claim 1, characterized in that, Before ridging, apply 3000-5000 kg / mu of well-rotted farmyard manure and 40-50 kg / mu of slow-release compound fertilizer.

3. The seed production method according to claim 1, characterized in that, The ratio of maternal row number to paternal row number is 4 to 6:2.

Images