WO2000059293A1

WO2000059293A1 - A process for producing hybrid rice seeds

Info

Publication number: WO2000059293A1
Application number: PCT/CN2000/000077
Authority: WO
Inventors: Qinxiu Li
Original assignee: Crop Institute, Sichuan Academy Of Agricultural Sciences
Priority date: 1999-04-06
Filing date: 2000-04-05
Publication date: 2000-10-12
Also published as: CN1115950C; AU3654100A; CN1227708A

Abstract

A process for producing hybrid rice (Oryza sativa) seeds comprises the following steps: selecting a male-sterile line as a female parent, which has sparse spikes, long stigma and slender-narrow grains smaller than restorer lines and is recessive tall; selecting a restorer line as a male parent, which has wide grains and the same growing period as that of the male-sterile line; mixedly sowing the seed of the male parent and the female parent in a ratio of 1:4; harvesting the seed of the mixedly planted parent plant; screening the hybrid rice seed by utilizing a sifter, the sieve mesh of which is smaller than the seed-grain of the restorer line and larger than the seed-grain of the male-sterile line. The process may reduce the production cost at least by 40 %. The sifter for using in the process is easily produced and highly effective. The random distribution of parent plants in field is better for cross-pollination than the orderly distribution.

Description

Method for producing hybrid rice seeds by screening method

Technical field

The invention belongs to the technical requirement field of rice heterosis utilization, and particularly relates to a method for producing hybrid rice seeds by a screening method. Background technique

Although China produces a large amount of hybrid rice seeds each year, the three-line technology is low in content and complex in field operations. The cost of producing hybrid rice seeds is five times that of commercial grain rice. Does not meet the requirements of low-consumption and efficient agriculture.

The specific flaws are:

1. There is no significant difference in grain width between the main sterile line and the restorer line. Almost all breeders and producers have not considered breeding sterile lines and restorer lines with large differences in grain width. Person apart. Of course, there are still many shortcomings that need to be improved for the current hybrid rice; the grain width is also ignored.

2. The United States mixedly mixed the yellow-grass sterile line with the golden-yellow restorer line, and then separated the seeds of the two with a photoelectric separator. The price of each double-tube separator is USD 18,000, which can separate 4 kg of hybrid rice seeds per hour. It is not appropriate for China to adopt this method.

3. The current seed production technology is based on the parents' ratio of 2: 8, 2: 7, 2: 9, etc., so that the parents are distributed in rows in Honda. Sterile lines far from the parent line often do not get enough pollen and are weak. In order to obtain sufficient pollen for the female parent far from the parent's bank, artificially assisted pollination was promoted. The bamboo rod was used to vigorously vibrate the parent to promote the flying. This is a very hard field job.

4. The current sterile lines have erect leaves that hinder pollen transmission; the current sterile lines have poor morale, and sometimes 40% of the male flowers of sterile lines cannot be drawn out of the sheath of the sword leaves; the current sterile lines are short The stigma and stigma exposure rate is usually less than 30% after the stigma is closed. To overcome these deficiencies, the removal of the flag leaves and the spraying of gibberellin stimulated heading and extended the stigma. At present, 15-20 grams of gibberellin (920) in Sichuan acres is about 3 yuan per gram, and this item costs 45-60 yuan per acre only.

The purpose of the present invention is to provide a method for producing hybrid rice seeds by a screening method, which makes the production of hybrid rice seeds easier and easier, and the production cost is reduced by using this method compared with the existing methods. Summary of the invention

The invention is implemented as follows:

A method for producing hybrid rice seeds by a screening method, in which the grain is smaller than the restorer grain and the narrow and narrow-grained iris-long stigma-vegetative recessive high-stalk sterile line is selected as the female parent, and the wide-grain type and the growth period and The same restorer line of the breeding line is the parent, and the two are mixed and planted according to the ratio of the seed ratio of the parent: 1: 1 to the seed. Out hybrids.

The 383A with average grain width of 2.05 0.15mm and maximum grain width <2.55mm was selected as sterile lines.

Select average grain width 3.09 ♦ 0.18mm, minimum grain width> 2.70mm. The average grain width of the female parent 383A differed from that of the male parent by 1.04mm. The difference between the minimum grain width of the restorer line and the maximum grain width of the sterile line is 0.15mm, which is F838.

The mesh of the mesh sieve is square, the diagonal of the eyelet is 3.0mm, and the length of the square hole is 2.5mm; the diameter of the circular sieve is 2.6mm.

Sterile and restorer seeds are mixed evenly at a ratio of 1: 1 or 1: 2 or 1 _: 3, and then sown and transplanted. Parents are randomly planted in the field.

The advantages and positive effects of the present invention are as follows:

1. Low cost. Sterile and restorer lines are mixed and sieved to produce seeds after hybrid harvesting, so that the field operation of hybrid rice seed production is almost the same as general rice production, and no additional investment is required. Compared with the current cumbersome field operations for seed production, the present invention can reduce the cost by at least 40%.

2. The design and manufacture of the screen are simple, easy to use and efficient. The photoelectric double-tube seeder in the United States sells for $ 18,000 each, and 4 kg of hybrid seeds per hour. The manual sieve price of the invention is 15 yuan, and 15 kilograms of hybrids are screened out per hour. The price of the manual sieve is one ten thousandth of the light motor, and an additional 11 kilograms of seeds are screened out per hour. The large-scale mobile sieve of the present invention also has a low manufacturing cost, and the splitting speed is dozens or hundreds of times higher than that of the optical motor.

3. The random distribution of parents in the field makes outcrossing pollination better than the current parental distribution. The invention uses fine-grain high-quality sterile lines to formulate high-quality and high-yield hybrid rice, so that the current situation of high-yield and poor-quality hybrid rice can be improved. Best Mode of the Invention

The specific implementation method of the present invention is as follows: Example 1:

The method for producing hybrid rice seeds by screening mainly includes two aspects: selection of sterile lines, selection and selection of restorer lines, and design of sieving tools, which are realized in the following steps.

1. Breeding of stigma, stigma, and recessive high-stalk sterile lines

The sterility line 383A which has been bred has these special traits. The average grain width is 2.054-0.15mm, the maximum grain width is <2.55mm, and the rice quality is slender and transparent without chalkiness. Without gibberellin, the stigma natural exposure rate of 383A is higher than 95. If the pollen supply is sufficient, the outcrossing seed setting rate can exceed 70%. The sparse-head sterility line 383A has an angle of 60-90Φ above the primary stalk and the axis of the cob, which makes small flowers distributed in a larger space and increases the chance of cross-pollination. The sparse panicle trait was inherited from the cross pollination type of long-medicine wild rice. The lamina traits make the ear layer above the leaf layer, and the recessive high stalk makes the sterile line 30 to 50 cm shorter than the maintaining line, so it is not necessary to cut leaves without applying gibberellin. Thorough removal of the maintainer line mixed with the sterile line ensures high purity.

2.Breeding or selecting wide-grain restorer lines

The average grain width of the restorer F838 was 3.09Φ 0.18mm, and the minimum grain width was> 2.70mm. The average grain width of the sterile line 383A and the restorer line F838 differed by 1.04 mm. The difference between the minimum grain width of the restorer line and the maximum grain width of the sterile line was 0.15 mm. Grain width has been shown to be a stable trait of a stereotyped line and does not change with environmental changes. The use of a mesh sieve can completely separate the sterile seed from the restorer line. In addition, 383A and F838

Simultaneous sowing and heading.

3.Screening design

The square hole sieve has a square hole, the diagonal of the eyelet is 3.0mm, the side length of the square hole is 2.5mm, and the diameter of the round hole sieve is 2.6mm. The sieve plate can be directly made of a commercially available four-mesh iron gauze or perforated on the iron sheet. The size of the sieve plate is determined as required. There are many types of manual screen, bench screen, hanging screen, motorized screen and sorting screen installed on the combine. However, the mesh size remains the same. '

In short, the sterile line to which the present invention is applicable is a stigma with thin leaves. The comprehensive economic condition is excellent, and the sterile line is obviously shorter than the maintaining line.

Sterile line and restorer line seeds are mixed according to a ratio of 1: 1, or 1: 2, or 1: 3, and then sown and transplanted. Parents are randomly distributed in the field. When harvesting, or after harvesting, the hybrid seed on the sterile line and the restorer seed are divided by a sorting sieve to obtain hybrid seeds. This puts the current The hybrid rice seed production operation becomes very simple and easy.

The obvious plant height difference between the sterile line and the maintainer line is easy to identify and remove the maintainer line mixed with the sterile line in the seed production field to ensure that the hybrid seed is of high purity.

The sterile lines suitable for the present invention are high-quality fine-grained types, which overcomes the shortcomings of the poorly-grained quality of the main sterile lines currently planted. The 383A used in the present invention has good comprehensive yield and high yield and quality of the first-generation hybrid hybrids formulated with the F838 and other groups.

Example 2:

1. Design, manufacture and use of sieve

A commercially available four-mesh wire screen is a key component of the screen. Careful inspection should be performed when purchasing. The mesh must be fine and consistent and not easily deformed. Cut the screen according to the size of the screen, and then nail the screen to the screen frame. Large-scale motorized screens are also made into screens and then driven with motorized components. The screen of the present invention is installed under the air sieve system of the combine, and the rice grains are sorted from the two exits of the parents and transported away after being sorted. The manual sieve, hanging sieve and motor sieve are used in the same way as the ordinary sieve method.

2.Pre-seeding mix of sterile line and restorer line

According to the local wind and cultivation conditions, mix the parental ratio of 1: 1, or 1: 2, or 1: 3 before sowing. In order to ensure that the parents can mix evenly, a small amount of mixed seeds under 15 kg can be fully stirred during soaking; when mixing thousands of kilograms of rice seeds, they can be divided into tightly covered iron buckets and rolled on the ground for dozens of meters; During mechanized seed production, the parent's own seed enters the coating machine according to the amount, and the seeds are mixed evenly after coating.

3. Breeding and selection of sterile lines and restorer lines

In order to obtain sterile lines and restorer lines suitable for the present invention, breeding has been carried out for more than two decades, with emphasis on the selection of sterile lines. The key traits that can significantly increase the rate of outcrossing are long stigma and Rousui type from long drug wild rice O.longistaninata and Liuzhou wild rice O.mfipogo; narrow and fine-grained traits from d275 and IR62529; leaf-like traits from RGS20; The high stalk comes from I 50eui; the male sterility traits and retention are from wild abortive CMS lines and maintainer lines Zhenshan 97A, 97B, etc. The above-mentioned traits are combined in 383A and 383B through complex processes such as compound hybridization, separation selection, and continuous backcrossing, which lays a foundation for the present invention.

The restoration system used in the present invention is to measure the grain width from the restoration system that has been finalized for trial or promotion in production, and first enable F838 with an average grain width> 2.9 mm. With the implementation of the present invention and the improvement of the perforations of the sieve. Any difference in maternal and paternal grain widths can be improved and used according to the principles of the present invention. ' 4. Field operation

The cultivation management is the same as that of general rice fields. The heading stage was significantly higher than that of the sterile line, and the maintainer line should be removed in time. In areas with no. 2 wind at noon of flowering, artificially assisted pollination will not be conducted. The present invention does not implement existing seed production technical measures such as cutting sword leaves, spraying gibberellin, and sowing parents in stages. Industrial Applicability The application of the present invention can reduce the cost by at least 40%. At the same time, the sieve of the present invention is simple in design and manufacture, convenient and efficient to use, and the present invention uses fine-grained sterile lines to formulate high-quality and high-yielding hybrid rice, so that the current hybrid rice has high yield The poor quality situation is improved and has a positive effect.

Claims

Rights request

1. A method for producing hybrid rice seeds by a screening method, characterized in that: grains are smaller than the restorer grains and fine and narrow grains are stigmatized and long stigma-vegetable recessive high-stalk sterile lines are selected as the female parent, and wide grain The restorer line with the same growth period and the sterile line is the male parent, and the two are mixed and planted according to the seed ratio of 1: 1 to 4 of the parent: the mother. The seeds are screened to select hybrids.

2. The method according to claim 1, characterized in that: 383A with an average grain width of seed grains of 2.05 ± 0.15 mm and a maximum grain width of <2.5511 dishes is selected as a sterile line.

3. The method according to claim 1, characterized in that: the average grain width 3.09 soil 0.18mm, minimum grain width> 2.70mm, the average grain width of the female parent 383A and the male parent is 1.04mm different, F838 with a difference of 0.15mm between the minimum grain width and the maximum grain width of the sterile line was a restorer line.

4. The method according to claim 1, characterized in that: the sieve openings of the mesh sieve are square, the diagonal of the perforations is 3.0 mm, and the side length of the square opening is 2.5 mm; the diameter of the round sieve opening sieve is 2.6 mm.

5. The method according to claim 1, characterized in that: the sterile line and the restorer line are mixed uniformly at a ratio of 1: 1 or 1: 2 or 1: 3, and then sown and planted, and the parents are randomly planted in the field .