Rapid breeding method of rice variety with excellent taste

Abstract

The invention relates to a rapid breeding method for breeding an excellent-taste rice variety, and belongs to the technical field of rice genetic breeding design. The rapid breeding method is characterized by comprising the following steps: (1) selecting three-level high-quality rice, japonica rice 'Salt rice No.8' with high stripe disease resistance, rice blast resistance, medium sheath blight resistance, moderate ripening period and high and stable yield as a female parent, and selecting a high-quality rice variety with no white heart and belly and no rice; the method comprises the following steps: (1) taking japonica rice 'Size 10' which has the rice quality reaching the ministerial high-quality rice first grade and medium resistance to bacterial blight, rice blast and stripe blight as a male parent, carrying out artificial hybridization and matching to obtain F0 seeds, (2) planting the F0 seeds into F1, and carrying out anther (microspore) culture on the F1 to form seedlings, and (3) after doubling, carrying out continuous directional selection for many years by adopting a pedigree method to breed the rice with the advantages of high and stable yield, high quality, disease resistance, moderate ripening period and high yield. The adaptability is wide, and the like. Breeding is rapid, and the breeding period is shortened.

Description

Technical Field

[0001] The present invention relates to a method for rapidly breeding excellent-taste rice varieties, belonging to the technical field of rice genetic breeding design. Background Art

[0002] As a food crop, the breeding requirements for rice varieties are high quality and palatability, high and stable yield, and multiple resistances and wide adaptability. Traditional breeding techniques such as hybridization, physical and chemical mutagenesis, etc. are widely used for the improvement of rice. Generally, in cross-breeding, germplasms with determined excellent traits are hybridized with some high-quality and disease-resistant rice varieties, and then generations of screening are carried out. The physical and chemical mutagenesis technique is to mutagenize rice varieties and then screen for specific trait mutants. Traditional breeding techniques have a long cycle and cumbersome operations. The microspore culture technique can be applied to germplasm innovation, utilization of heterosis, and crop molecular breeding. The anthers of hybrid F1 plants contain rich and diverse gene recombinant gametophytes (microspores). The culture of F1 microspores can rapidly aggregate and homozygose the excellent traits recombined by both parents. After the regenerated plants are chromosome-doubled, all traits are homozygous at once and can be directly used for screening target traits. Summary of the Invention

[0003] Object of the Invention: China has achieved world-leading achievements in rice breeding, and has successively implemented rice dwarfing breeding, three-line and two-line hybrid rice breeding. In japonica rice breeding, great achievements have been made, and a large number of new japonica rice varieties with high yield, good quality, and multiple resistances have been bred, making important contributions to ensuring China's food security. With the continuous improvement of people's living standards, the demand for rice has also changed profoundly. There is an urgent need in production for new japonica rice varieties with excellent grain quality, good resistance, and high yield. Therefore, domestic breeding institutions have also begun to adjust their rice breeding goals and regard high quality and high yield as the primary selection criteria. Rapidly breeding new japonica rice varieties with characteristics such as high yield, good quality, and strong resistance has good prospects for popularization and application.

[0004] Technical Solution: To solve the above technical problems, the technical solution adopted by the present invention is: a method for rapidly breeding excellent-taste rice varieties. It mainly includes: artificially hybridizing Yandao 8 with Sidao 10, culturing the anthers (microspores) of F1 into seedlings, and after doubling, adopting the pedigree method to conduct continuous directional selection for many years to breed a new conventional medium japonica rice variety with characteristics such as high and stable yield, high quality and disease resistance, moderate maturity, and wide adaptability. The specific implementation plan is as follows:

[0005] (1) Select the japonica rice "Yandao 8" with third-class high-quality rice, highly resistant to stripe leaf blight, resistant to rice blast, moderately resistant to sheath blight, moderate maturity, and high and stable yield as the female parent, and select the japonica rice "Sidao 10" without abdominal white, with rice quality reaching the first-class of the ministerial high-quality rice, moderately resistant to bacterial blight, rice blast, and stripe leaf blight as the male parent, and conduct artificial hybridization and combination in Yancheng, Jiangsu to obtain F0 seeds;

[0006] (2) Plant the obtained F0 seeds to F1. At the booting stage, select panicles of different sizes, pick microspores in the anthers for microscopic examination, conduct FDA staining to detect cell viability, select young panicles with most microspores in the late uninucleate to early binucleate development stage, wrap them with plastic wrap and place them in a 4°C refrigerator, and set the treatment time to 8d - 16d;

[0007] (3) Select the above-mentioned young panicles, use 2% NaClO + 2 drops of Tween - 20, place them on a shaker for 20 min for surface disinfection, then rinse them 3 times with sterile water in a laminar flow hood. Put the anthers into a culture medium containing 5 ml of 0.3 M mannitol and a working concentration of 200 mg / l cefotaxime. The isolated anthers are pretreated at 32°C in the culture medium for 3 d, and free microspores are collected;

[0008] (4) Pipette 2 ml of the above-collected free microspores into the induction medium, and culture them in the dark at 33°C for 2 d, then continue to culture them in the dark at 25°C for 50d - 120d to form haploid callus;

[0009] (5) Select the above callus in the differentiation medium, with a light intensity of 1500 lx, 16 h / d, and a temperature of 26°C, and culture for 30 d to form small seedlings.

[0010] (6) Select healthy in vitro regenerated seedlings and transplant them onto the rooting medium, 2 - 3 plants per bottle, with a light intensity of 1500 lx, 16 h / d, and a temperature of 26°C, and culture for 2 - 4 weeks until the small seedlings grow complete roots.

[0011] (7) Take the root tips of the seedlings, identify the ploidy by methods such as flow cytometry or root tip chromosome counting, treat them with colchicine for doubling to obtain doubled haploid plants, and carry out acclimatization and transplanting;

[0012] (8) Plant the DH lines in the line identification nursery in Yancheng, Jiangsu. Also plant two parents as controls. At the heading stage, conduct inoculation identification of resistance to bacterial blight and panicle neck blast respectively. The selection criteria for the selected lines (individual plants) are that the maturity period is between the two parents, and other traits are the same as those in conventional breeding;

[0013] (9) Enter the seeds harvested from the above-selected line identification nursery into the variety comparison test. Also plant two parents as controls. At the same time, conduct comprehensive trait screening and comparison of maturity period, yield, resistance, and quality. Select lines with a yield equivalent to that of the control Xudao 3, or a yield reduction of no more than 3%; the quality indicators meet the national second-class high-quality rice standard, resistant - moderately resistant to bacterial blight, with a disease level of 0 - 3; resistant - moderately susceptible to rice blast, and the disease levels of the panicle neck blast incidence and panicle neck blast loss index are both 0 - 5. Breed a new variety that shows a whole growth period 7 - 8 days earlier than the control Xudao 3 in the Jiangsu Huaibei region, and the yield, resistance, and quality indicators meet the provincial-level or above rice variety approval standards.

[0014] (10) The other traits are the same as those in conventional breeding: select individuals with a relatively compact plant type equivalent to the control Xudao 3, green coleoptiles, 3-5 cm shorter than the control Xudao 3, 17-18 main stem leaves, and all indexes of rice quality reaching the national second-class high-quality rice standard. In the F5 generation, select individuals with resistant-moderately resistant to bacterial blight, disease grade 0-3; resistant-moderately susceptible to rice blast, and the disease grades of panicle neck blast incidence and panicle neck blast loss index are both 0-5 grades.

[0015] Beneficial effects: The present invention provides a rapid breeding method for breeding an excellent-taste rice variety. This breeding method involves artificially crossing Yandao 8 with Sidao 10, culturing the anthers (microspores) of F1 into seedlings, doubling them, and then using the pedigree method to continuously and directionally select for many years to breed a new conventional medium japonica rice variety with characteristics such as high and stable yield, high quality and disease resistance, moderate maturity, and wide adaptability. It enables rapid breeding and shortens the breeding period.

Claims

1. A rapid breeding method for fine - eating - quality rice varieties, characterized as follows: (1) Select the japonica rice "Yandao 8" with third - grade high - quality rice, highly resistant to stripe leaf blight, resistant to rice blast, moderately resistant to sheath blight, moderate maturity, high and stable yield as the female parent, and select the japonica rice "Sidao 10" without ventral white, with rice quality reaching the first - grade of ministerial - level high - quality rice, moderately resistant to bacterial blight, rice blast, and stripe leaf blight as the male parent. Conduct artificial hybridization and combination in Yancheng, Jiangsu to obtain F0 seeds. (2) Plant the obtained F0 seeds to get F1. When in the booting stage, select panicles of different sizes, pick microspores in anthers for microscopic examination, conduct FDA staining to detect cell viability, select young panicles with most microspores in the late - mononuclear to early - binuclear development stage, wrap them with plastic wrap and put them into a 4°C refrigerator, and set the treatment time to 8d - 16d. (3) Select the above - mentioned young panicles, use 2% NaClO + 2 drops of Tween - 20, place them on a shaker for 20 min for surface disinfection, then rinse them 3 times with sterile water in a laminar flow hood. Put the anthers into a culture medium containing 5 ml of 0.3M mannitol and cefotuxime with a working concentration of 200 mg / l. Pretreat the isolated anthers at a low temperature of 32°C in the culture medium for 3d, and collect free microspores. (4) Pipette 2 ml of the above - collected free microspores into an induction medium, conduct dark culture at 33°C for 2d, and continue dark culture at 25°C for 50d - 120d to form haploid callus. (5) Select the above - mentioned callus in a differentiation medium, with a light intensity of 1500 lx, 16 h / d, and a temperature of 26°C, and culture for 30d to form small seedlings. (6) Select healthy in - vitro regenerated seedlings and transplant them onto a rooting medium, 2 - 3 plants per bottle, with a light intensity of 1500 lx, 16 h / d, and a temperature of 26°C, and culture for 2 - 4 weeks until the small seedlings grow complete roots. (7) Take the root tips of the seedlings, identify the ploidy by methods such as flow cytometry or root - tip chromosome counting, treat with colchicine for doubling, obtain doubled haploid plants, and carry out acclimatization and transplanting. (8) Plant the DH lines in a line - identification nursery in Yancheng, Jiangsu. Also plant two parents as controls. Conduct inoculation identification of resistance to bacterial blight and panicle neck blast at the heading stage. The selection criteria for the selected lines (individual plants) are that the maturity is between the two parents, and other traits are the same as those in conventional breeding. (9) Enter the seeds harvested from the above - selected line - identification nursery into a variety - comparison test. Also plant two parents as controls. At the same time, conduct comprehensive trait screening and comparison of maturity, yield, resistance, and quality. Select the lines with a yield equivalent to that of the control Xudao 3 or a yield reduction of no more than 3%; the quality index reaches the national standard of high - quality rice above the second - grade; resistant - moderately resistant to bacterial blight, with a disease level of 0 - 3; resistant - moderately susceptible to rice blast, and the disease levels of the panicle neck blast incidence and panicle neck blast loss index are both 0 - 5. Breed a new variety that shows a whole - growth - period 7 - 8 days earlier than the control Xudao 3 in the Huaibei area of Jiangsu, and the yield, resistance, and quality index meet the provincial - level or above rice variety approval standards.

2. The rapid breeding method of an excellent eating-quality rice variety according to claim 1, characterized in that, In steps (2) to (7) above, the excellent traits of parental recombination are rapidly aggregated and homozygosed by using F1 microspore culture.