Improved variety breeding method for breeding new japonica rice strain

Abstract

The invention provides an improved variety breeding method for breeding a new japonica rice strain, and relates to the technical field of new plant variety breeding, which comprises the following steps of: putting a japonica rice hybrid F5 generation material into a strain identification nursery in a single plant form, preferably selecting a single ear for the second time to establish a three-nursery in advance, innovating seeds of ear rows, ear lines and stock seeds, and adopting'classified low-temperature preservation and year-by-year use '. An improved seed breeding method combining SSR molecular marker rapid detection is adopted, and cultivation technologies such as mechanical transplanting of small seedlings and sparse sowing of long seedling age are deeply fused with a japonica rice stock seed production technology. The method not only can realize on-demand expanding propagation of ear rows and ear lines, but also can screen out heterogeneous residual genes and strictly prevent gene drift, ensures the purity and excellent seed nature of seeds, achieves the effects of purification, fidelity and rejuvenation, and promotes large-area popularization and application of bred and approved varieties.

Description

Technical Field

[0001] The present invention relates to the technical field of breeding new plant varieties, and particularly to a method for breeding improved seeds of a newly developed japonica rice strain. Background Art

[0002] The breeding of improved seeds is an important part of seed work. It is a continuation of breeding work, a foundation for promoting new and excellent varieties, an important way to improve agricultural productivity, the competitiveness of agricultural products in the market, and increase farmers' income, and an important measure to improve agricultural production efficiency. Accelerating the research on the improved seed breeding system, exploring and screening simple, easy-to-implement, economical and efficient original seed production technologies that match excellent seeds with good cultivation methods. At present, the main original seed production technologies for rice are the "three-nursery system", the "two-nursery system", the "one-nursery system" and the "strain cycle method", etc. The most commonly used "three-nursery system" has been restricted to a certain extent due to problems such as long time required, large workload, and complicated operation procedures. Therefore, exploring a simple, easy-to-implement, economical and efficient new original seed production technology, establishing and improving the improved seed breeding system for conventional rice varieties, establishing a scientific and rigorous improved seed breeding system, and producing seeds with high purity and good quality are urgent problems to be solved at present. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for breeding improved seeds of a newly developed japonica rice strain to solve the technical problems such as long time, large workload, and complicated operation procedures in the current rice original seed production technology.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A method for breeding improved seeds of a newly developed japonica rice strain, comprising the following steps:

[0006] 1) Single plants of advanced-generation materials are put into the identification nursery, and an advanced-generation plant row identification nursery is established. The plastic tray seedling raising and thinning and purification methods are adopted. One tray is sown with 2 single plant strains, and the seeding rate of each strain is controlled at about 1000 grains. There are 2 - 3 seedlings per hole, and the planting area is about 8 m 2 or so. The selected strains are harvested in whole areas and single ears are preferably selected for purification;

[0007] 2) Excellent and basically stable strains are subjected to multi-point variety comparison tests. Three trays are sown for each strain, with a seeding rate of 100 g per tray. The small seedlings are transplanted, with 4 - 5 seedlings per hole, and there are three replicates. The planting area is 15 m 2 ;

[0008] The corresponding advanced-generation ear row nursery is planted in spring in Hainan, with single-plant transplanting, and the area of the ear row nursery is 1 m 2 ;

[0009] The corresponding advanced-generation ear line nursery is planted in the normal season. Six trays are sown for each ear line, with a seeding rate of 90 g per tray. Machine transplanting is carried out, with 4 - 5 seedlings per hole, and the planting area is 80 m 2 ;

[0010] 3) For the selection of pre-experimental strains at or above the provincial level, select seeds from a highly pure ear line nursery, and divide the ear line nursery into two parts. One part is used for planting the ear line nursery, and the other part is stored at low temperature.

[0011] 4) In the first year of the advancement to the regional trial, select the seeds harvested from the ear line nursery and conduct cyclic planting of the ear lines; select single ears for optimization and purification, and re-establish the ear row nursery.

[0012] 5) The seeds of the ear lines with the best performance and high purity are used as the seeds for the second-year strains in the advancement to the regional trial.

[0013] 6) For the seeds entering the production trial, use the secondarily optimized ear line seeds, and use the ear line seeds to multiply and plant the original seed field. Establish an ear line nursery with the ear row seeds of the previous year, and store the ear line seeds with excellent performance and good purity at low temperature.

[0014] 7) When the strain passes the certification, plant the original seed field in different regions with the ear line seeds, and strengthen demonstration and promotion.

[0015] Preferably, for the strains that are still not stable in the multi-point variety comparison test, continue to optimize and purify single ears, track with SSR molecular markers, and finally obtain excellent strains with stable high purity before they can be recommended to participate in pre-experimental trials at or above the provincial level.

[0016] Preferably, for the strains entering the first year of the regional trial, they have reached the basic stable stage, with consistency and stability. With the increase of generations, there is still the possibility of remaining variation. It is necessary to re-optimize single ears and establish an ear row nursery. This can not only strictly prevent gene drift from deviating from the authenticity of the variety, achieve the effect of purifying consistency and maintaining typicality, but also ensure that the best excellent genes of the variety are not lost, achieve the effect of purification and rejuvenation with good yield and better comprehensive resistance, and fully maintain the excellent characteristics of the new variety.

[0017] The beneficial effects of the present invention are as follows:

[0018] In the present invention, the F5 generation materials of japonica rice hybrids enter the strain identification nursery in the form of single plants, and single ears are secondarily optimized to establish the three nurseries in advance. The seeds of ear rows, ear lines, and basic seeds are innovated, and a method for breeding improved seeds is adopted, which combines "classified low-temperature preservation and annual use" with the SSR molecular marker rapid detection method. The cultivation techniques such as machine-transplanted small seedlings and sparse sowing with long seedling age are deeply integrated with the japonica rice original seed production technology. It can not only multiply the ear rows and ear lines as needed, but also screen out heterogeneous residual genes, strictly prevent gene drift, ensure the seed purity and excellent characteristics, achieve the effect of purification, authenticity, and rejuvenation, and thus fully explore the potential excellent and homozygous gene expression production capacity of the variety, and promote the large-scale popularization and application of the varieties approved for release. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of a method for breeding improved seeds of a newly developed japonica rice strain. Detailed implementation manners

[0020] For ease of understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0022] The specific embodiments of the present invention will be described below with reference to the drawings.

[0023] Embodiment 1

[0024] In this embodiment, a method for breeding improved seeds of a new japonica rice strain is proposed. Please refer to Figure 1 , and the method for breeding improved seeds of the new japonica rice strain specifically includes the following processes:

[0025] In 2019, in the experimental field of Yancheng Institute of Dahuazhongye Breeding Research Institute, 3-5 individual plants were selected from high-generation materials of each strain for the identification nursery. The individual plants of high-generation materials emphasized typicality and outstanding high yield, avoiding deviation from the authenticity of the strain. A high-generation plant row identification nursery was established. The plastic tray seedling raising and thinning and purification methods were adopted. For 2 individual plant strains, 1 tray was sown, and the sowing amount per strain was controlled at about 1000 grains. There were 2-3 seedlings per hole, and the planting area was about 8 m 2 ; The selected strains were harvested in whole plots and 100 single ears were preferably selected for purification.

[0026] In 2020, in the experimental fields of 6 different ecological regions such as Huai'an Institute, Yancheng Institute, and Lianyungang Institute of Dahuazhongye Breeding Research Institute, multi-point variety comparison tests were carried out on the strains with excellent performance and basically stable. For each strain, 3 trays were sown, with a sowing amount of 100 g per tray. Small seedlings were transplanted, with 4-5 seedlings per hole, and three replicates were set. The planting area was 15 m 2 ; In spring in Hainan, the corresponding high-generation ear row nursery was planted, with single-plant transplanting, and the area of the ear row nursery was 1 m 2 ; In the main season, the corresponding high-generation ear line nursery was planted. For each ear line, 6 trays were sown, with a sowing amount of 90 g per tray. Machine transplanting was carried out, with 4-5 seedlings per hole, and the planting area was 80 m 2 .

[0027] In 2021, it is recommended to participate in the provincial and above preliminary test varieties to select high purity 8kg ear row garden to harvest seeds, and plant the corresponding high-generation ear line garden, sow 6 trays for each ear line, sow 90g per tray, machine transplanting, 4-5 seedlings per hole, and planting area of 80m 2 .

[0028] In 2022, the advanced regional trial varieties will select 15kg of seeds harvested from the spike nursery, and carry out spike cycle planting. After the single spike is selected for optimization and purification, the spike row nursery will be re-established. When sowing, each seedling tray will be customized with a 5-grid wooden block frame, 5 single spikes will be sown in 1 tray, and the sowing amount of each single spike will be controlled at about 100 seeds. Single planting, the spike row nursery area is 1m 2 .

[0029] In 2023, 15kg of seeds from the best performing and pure high-ear line will be used to supply seeds for the second year of regional trials.

[0030] In 2024, 40 kg of seeds of the secondary selected ear line will be used for production test seeds, and the ear line seeds will be used to propagate the original seed fields. The ear line seeds from the previous year will be used to establish an ear line nursery. The ear line seeds with excellent performance and good purity will be stored at low temperatures or propagated in a cycle to establish high-quality original seed nurseries and variety display fields to ensure that the seed purity reaches more than 99.99%.

[0031] During the tillering period of the ear row and ear system nursery, the focus is on disease resistance, plant leaf shape and growth potential, and follow-up observation and record. During the heading and filling period, the plant leaf posture and leaf color, heading uniformity, heading period, etc. are observed, and compared with the control. For those with obvious variations and poor growth, poles are inserted in time and eliminated. During the maturity period, disease resistance and high yield are considered. The selected ear rows and ear systems are harvested, threshed and stored individually. The indoor final selection mainly depends on the grain shape, grain color, grain weight, quality, etc.

[0032] In this embodiment, single plants and single ears are raised in plastic trays, and sparse sowing and long seedling age technology is adopted. The seedlings are more than 25 days old and have 4-5 leaves. Sparse and even sowing is required to ensure strong seedlings, well-developed root systems, and early and stable growth.

[0033] This embodiment proposes a method for breeding improved varieties of japonica rice. The following key points need to be paid attention to in fertilizer management, water and pulp management, greening period, jointing-heading stage, grain filling-maturity stage and the late stage of rice grain filling:

[0034] Fertilizer management: When the seedlings have 1 leaf and 1 heart, apply weaning fertilizer once, 7.5kg urea / mu. Apply tillering fertilizer once more at the 3-leaf stage, 7.5kg urea / mu. Apply N22-24kg / mu, 6kg phosphorus pentoxide, 4kg potassium oxide throughout life, and the ratio of basal tillering fertilizer to spike and grain fertilizer is preferably 7:3; apply basal fertilizer before stubble removal, 5kg urea / mu + 10kg triple compound fertilizer / mu; apply green fertilizer after the plants are alive, 10kg urea / mu, and apply tillering fertilizer in time, 10kg urea / mu; apply 10kg urea / mu of flower-promoting fertilizer + 10kg triple compound fertilizer / mu, and apply 5-7.5kg / mu of flower-preserving fertilizer depending on the seedling condition.

[0035] Water and slurry management: adhere to the transplanting method of "thin water for transplanting and thin water for raising seedlings". When transplanting, the field surface should be kept in "spotted water" and the water depth should be controlled at 0.5-2cm for the most suitable; after transplanting, insist on exposing the field to promote "roots", irrigate during the day and expose the leaves at the lowest part of the field above the water surface, and achieve "shallow water is clear every time, the previous water is not consumed, and the later water is not accumulated". According to the principle of "thin water to keep the plants alive, moisture to promote tillering, shallow water frequent irrigation, alternating dry and wet", do not water on cloudy days, and drain the field water on rainy days to allow the fragile "root system" to ventilate and revive. Only with strong roots can there be more tillers.

[0036] Greening period: Adhere to moist irrigation with "running water" and do not establish a shallow water layer too early in the tillering period. When the seedlings reach 6-7 leaves, establish a shallow water layer appropriately to promote the low-position tillering of the seedlings and ensure that 100% of the leaf positions of the three main stems of "5-6-7" are tillered. The shallow water layer is generally 2-3cm. After the water layer dries up, expose the field for 1-2 days and then establish a shallow water layer. Repeat this process, always keep the field surface alternately dry and wet, until the field is "enough for seedlings" and start to rest; 20-25 days after planting, the predetermined number of ears of seedlings must be reached, and "light resting in stages" is the main method, and "running water" is cleared every time, and "the front water is not clear, and the back water will not enter" and other open field management measures are adopted.

[0037] Jointing-heading stage: "alternating dry and wet" water and slurry management method should be adopted. During this period, except for maintaining a certain water layer between the "reduction tillering stage-heading and flowering stage" to prevent the degradation of spikelets, the rest of the time should be kept "soil moist, the latter water does not suppress the former water, and the former and latter water are clear each time", and the field soil should be kept in a state of not being irrigated unless it is dry.

[0038] Filling and solidification-maturity stage: adhere to the principle of "clear water hard board, alternating dry and wet, frequent shallow water irrigation and clear each time (the front water must not be seen in the back water)" to improve root vitality, nourish roots and leaves, and prevent premature aging.

[0039] In the later stage of rice fruiting: the main focus should be on "dryness", and water should be cut off in time. Generally, water should be cut off 10-15 days before rice harvest.

[0040] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0041] The above-described embodiments only express several implementation manners of the present invention, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A method for the seed breeding of a new japonica rice strain, characterized in that, It includes the following steps: 1) High-generation materials emphasize the typicality of individual plants, highlight high yield, and avoid deviating from the authenticity of the strain. Establish a high-generation plant row identification nursery, and adopt the methods of plastic tray seedling raising and thinning and purification. Sow 1 tray for 2 individual plant strains, control the sowing rate of each strain at about 1000 seeds, 2-3 seedlings per hill, and the planting area is about 8 m 2 or so. The selected strains are harvested in whole plots and purified by single ears; 2) Conduct multi-point variety comparison tests on strains with excellent and stable performance. Sow 3 trays for each strain, with a seeding rate of 100 g per tray. Transplant small seedlings, with 4 - 5 seedlings per hole, and repeat three times. The planting area is 15 m 2 ; In Hainan, a relatively advanced ear row nursery corresponding to spring planting is established, with single-stem planting, and the area of the ear row nursery is 1 m 2 ; The high-generation ear line nursery corresponding to the normal-season planting, sowing 6 trays for each ear line, with a sowing rate of 90 g per tray, transplanting by machine, 4 - 5 seedlings per hill, and a planting area of 80 m 2 ; 3) For the selected seeds of the high-purity ear line nursery for the preliminary test above the provincial level, divide the ear line nursery into two parts. One part is used for planting the ear line nursery, and the other part is stored at low temperature; 4) For the lines in the first year of the advanced regional trial, select the seeds harvested from the ear line nursery and conduct ear line cyclic planting; select single ears for optimization and purification, and re-establish the ear row nursery; 5) The seeds of the ear line with the best performance and high purity are used as the seed supply for the lines in the second year of the advanced regional trial; 6) For the seeds entering the production test, use the secondarily selected ear line seeds, and use the ear line seeds to expand and plant the original seed field. Use the ear row seeds of the previous year to establish the ear line nursery, and store the seeds of the ear line with excellent performance and good purity at low temperature; 7) When the line passes the certification, plant the original seed field in different regions with the ear line seeds, and strengthen demonstration and promotion.

2. A method for the improved seed propagation of a new japonica rice strain according to claim 1, characterized in that: For the lines that are still unstable in the multi-point variety comparison test, it is necessary to continue to select single ears for purification, supplemented by SSR molecular marker tracking, and obtain stable and high-purity excellent lines before they can be recommended to participate in the preliminary test above the provincial level.

3. A method for the improved seed propagation of a new japonica rice strain according to claim 1, characterized in that: For the lines in the first year of entering the regional trial, when there may still be residual gene mutations after the generation increases, it is necessary to re-select single ears and establish the ear row nursery.

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