Breeding and application of strong-winterness colored-flower rape germplasm

Abstract

The invention relates to the technical field of agricultural biology, in particular to breeding and application of a strong-winterness colored-flower rape germplasm. Comprising the following steps: self-crossing semi-winter rape to obtain separated progeny seeds; sowing in Lanzhou, and screening overwintering reviving winterness single plants; performing mixed pollination and hybridization on the single plant with strong winterness, LY29 and orychophragmus violaceus; screening male sterile plants from the F1 generation and continuously backcrossing for 4 generations; fertile plants are pollinated and sterile plants are backcrossed for four generations to stabilize flower colors; the germplasm is determined when the overwintering rate is greater than or equal to 75% in The invention provides a novel rape germplasm with strong winter cold resistance and stable colored petal character, so that the problem that colored flower rape cannot safely overwinter in northern drought and cold regions is solved, meanwhile, the planting area and application scene of the colored flower rape are expanded, and the variety of the colored flower rape germplasm is developed through an innovative breeding method. The radish cytoplasmic male sterile line, the strong winter rape parent (LY29) and the flower color gene of the distant species orychophragmus violaceus are successfully integrated, the directional cultivation of the strong winter colored flower rape germplasm is realized, and the technical blank in the field is filled.

Description

Technical Field

[0001] The invention relates to the field of agricultural biotechnology, and in particular to the breeding and application of strong winter-resistant colored flower rapeseed germplasm. Background Art

[0002] Rapeseed (Brassica napus L.) is one of the important oil crops in my country, with both economic and ornamental value. In recent years, colored rapeseed has gradually become a new highlight of landscape agriculture and rural tourism due to its unique flower colors (such as orange, pink, purple, etc.). However, the colored rapeseed germplasm currently on the market is mainly spring or semi-winter varieties, which have weak cold resistance and cannot adapt to the extreme low temperature environment in the arid and cold areas of northern my country (such as Lanzhou and Tianshui in Gansu). Specifically, when the existing colored rapeseed varieties are sown in the autumn in the arid and cold areas of the north, the overwintering rate is significantly reduced due to the long duration of low temperatures in winter and frequent frost damage, making it difficult to achieve large-scale planting.

[0003] In the prior art, although some winter rapeseed varieties with strong cold resistance (such as the strong winter variety LY29) have been developed, these varieties generally lack flower color diversity and are difficult to meet the market demand for ornamental rapeseed. In addition, conventional breeding methods face significant technical bottlenecks when combining strong winter resistance with flower color traits: after hybridization of spring or semi-winter colored flower germplasm with strong winter parents, the offspring often have degraded wintering ability due to differences in temperature sensitivity, or the flower color trait separation is unstable and difficult to be stably inherited. Summary of the invention

[0004] The present invention provides a new rapeseed germplasm with both strong winter cold resistance and stable colored petal traits, so as to solve the problem that colored rapeseed in the northern arid and cold regions cannot safely overwinter, while expanding its planting areas and application scenarios. Through innovative breeding methods, the flower color genes of radish cytoplasmic male sterile line, strong winter rapeseed parent (LY29) and distant species February orchid are successfully integrated, realizing the directional cultivation of strong winter colored rapeseed germplasm, filling the technical gap in this field.

[0005] The technical solution adopted by the present invention is: a breeding method for strong winter color flower rapeseed germplasm, comprising the following steps:

[0006] S1: Self-pollination of radish cytoplasmic semi-winter rapeseed hybrid TY2288 to obtain segregating progeny seeds;

[0007] S2: sowing the segregated progeny seeds in Lanzhou, Gansu, and selecting strong winter-tolerant plants that survive the winter and turn green;

[0008] S3: The strong winter-resistant single plant selected in S2 was used as the female parent, and the mixed pollen of the strong winter-resistant rapeseed variety LY29 and February orchid was used for hybridization to obtain F1 generation seeds;

[0009] S4: F1 seeds were sown in Lanzhou, Gansu, and male sterile plants that survived the winter were selected. The mixed pollen of LY29 and February orchid was used for backcrossing. The backcrossing was repeated for 4 generations to obtain a male sterile line with stable petal color and strong winter resistance.

[0010] S5: The pollen of the fertile individual plants of the backcross offspring in S4 is transferred to the corresponding male sterile individual plants, and the backcross is continued for 4 generations until the flower color is stable;

[0011] S6: The finally obtained colored rapeseed germplasm is sown in the northern arid and cold regions to verify that its overwintering rate is ≥ 75%, and it is determined to be a strong winter colored rapeseed germplasm.

[0012] As a further improvement of the present invention, the petal color includes at least one of orange, light pink, purple, and pink.

[0013] As a further improvement of the present invention, the northern arid and cold region includes Lanzhou, Gansu and Tianshui, Gansu.

[0014] As a further improvement of the present invention, the number of backcrossing in S4 is 4, and after each backcrossing, individual plants with differentiated petal colors are screened out.

[0015] The invention relates to an application of the strong winter color flower rapeseed germplasm bred by the above method in autumn planting in the northern arid and cold regions.

[0016] As a further improvement of the present invention, the germplasm is sown in arid and cold areas with a wintering rate of ≥75% to achieve large-scale planting of colored rapeseed.

[0017] A strong winter-resistant colored flower rapeseed germplasm is bred by the above method and can stably express orange, light pink, purple and pink petal traits under the condition that the overwintering rate in the northern arid and cold regions is ≥75%.

[0018] As a further improvement of the present invention, the cold resistance of the germplasm is significantly higher than that of spring and semi-winter colored flower rape varieties.

[0019] As a further improvement of the present invention, the flower color of the germplasm remains stable after four consecutive generations of planting.

[0020] Beneficial effects of the present invention: (1) The present invention, through targeted screening of strong winter-resistant individual plants and combined with multi-generation backcrossing technology, cultivates colored rapeseed germplasm with a wintering rate of ≥75% in the northern arid and cold regions (such as Lanzhou and Tianshui, Gansu), breaking through the limitation that the existing colored rapeseed cannot safely overwinter in this region due to its spring or semi-winter characteristics, expanding its planting range, and providing new germplasm resources for landscape agriculture and oil production in high-cold areas. (2) The present invention uses distant hybridization (February orchid) and continuous backcrossing technology to successfully integrate orange, light pink, purple, pink and other petal color genes, and through more than 4 generations of backcrossing screening, the flower color remains stably expressed after 4 generations of continuous planting, solving the technical problem of unstable flower color separation in traditional breeding and meeting the market's diversified demand for ornamental rapeseed. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] The present invention provides a breeding method for strong winter-resistant colored flower rapeseed germplasm, comprising the following steps:

[0023] S1: Self-pollination of radish cytoplasmic semi-winter rapeseed hybrid TY2288 to obtain segregating progeny seeds;

[0024] S2: sowing the segregated progeny seeds in Lanzhou, Gansu, and selecting strong winter-tolerant plants that survive the winter and turn green;

[0025] S3: The strong winter-resistant single plant selected in S2 was used as the female parent, and the mixed pollen of the strong winter-resistant rapeseed variety LY29 and February orchid was used for hybridization to obtain F1 generation seeds;

[0026] S4: F1 seeds were sown in Lanzhou, Gansu, and male sterile plants that survived the winter were selected. The mixed pollen of LY29 and February orchid was used for backcrossing. The backcrossing was repeated for 4 generations to obtain a male sterile line with stable petal color and strong winter resistance.

[0027] S5: The pollen of the fertile individual plants of the backcross offspring in S4 is transferred to the corresponding male sterile individual plants, and the backcross is continued for 4 generations until the flower color is stable;

[0028] S6: The finally obtained colored rapeseed germplasm is sown in the northern arid and cold regions to verify that its overwintering rate is ≥ 75%, and it is determined to be a strong winter colored rapeseed germplasm.

[0029] The petal color of the present invention includes at least one of orange, light pink, purple and pink. The northern arid and cold region includes Lanzhou, Gansu and Tianshui, Gansu. The number of backcrossings in S4 is 4, and after each backcrossing, individual plants with differentiated petal colors are screened.

[0030] The application of the strong winter color rapeseed germplasm bred by the above method in autumn planting in the arid and cold regions of the north includes sowing the germplasm in the arid and cold regions with a wintering rate of ≥75% to achieve large-scale planting of color rapeseed.

[0031] A strong winter colored flower rapeseed germplasm is obtained by breeding the above method and can stably express orange, light pink, purple and pink petal traits under the condition that the wintering rate in the northern arid and cold regions is ≥75%. The cold resistance of the germplasm is significantly higher than that of spring and semi-winter colored flower rapeseed varieties. The flower color of the germplasm remains stable after 4 consecutive generations of planting.

[0032] Example:

[0033] 1. Materials and test sites

[0034] (1) Test materials:

[0035] Female parent: radish cytoplasm semi-winter rapeseed hybrid TY2288 (provided by the Oil Crops Research Institute of Gansu Academy of Agricultural Sciences);

[0036] Male parent: strong winter rapeseed variety LY29 (strong cold resistance, wintering rate ≥ 80%) and distantly related species February orchid (flower color gene donor).

[0037] (2) Experimental sites: Experimental field in Lanzhou New District, Gansu Province (36°03′N, 103°40′E, 1520 m above sea level, average annual temperature 6.3°C, average temperature in January -7.5°C); Experimental field in Maiji District, Tianshui City, Gansu Province (34°33′N, 105°42′E, 1130 m above sea level, average annual temperature 11.5°C, average temperature in January -2.8°C).

[0038] (II) Implementation steps

[0039] Step S1: Obtaining seeds from self-pollination segregation progeny

[0040] In September 2019, TY2288 seeds were sown in the experimental field of Lanzhou New District with a row spacing of 30 cm and a plant spacing of 15 cm, and conventional field management was performed. Mature seeds were harvested in June 2020, and full seeds were selected as self-segregating progeny (S1 generation).

[0041] Step S2: Screening of strong winter-resistant plants

[0042] In September 2020, the S1 generation seeds were sown at the same density in the experimental field of Lanzhou New District. The survival rate was counted during the wintering and greening period in March 2021, and strong wintering plants with a wintering rate ≥ 80% (a total of 120 plants) were screened and marked as TY2288-LZ-1 to TY2288-LZ-120.

[0043] Step S3: hybridization to obtain F1 generation seeds

[0044] In April 2021, 10 strong winter plants including TY2288-LZ-35, TY2288-LZ-67, and TY2288-LZ-89 were selected as female parents. After artificial emasculation, they were pollinated with mixed pollen of LY29 and February orchid (pollen mixing ratio 3:1). After pollination, they were bagged for isolation, and pollination was repeated once after 7 days to obtain hybrid F1 generation seeds.

[0045] Steps S4-S5: Backcross screening and flower color stabilization

[0046] F1 generation sowing and backcrossing: F1 generation seeds were sown in Lanzhou New District in September 2021, and male sterile plants that survived the winter and turned green were selected in March 2022 (accounting for about 65%). The sterile plants were pollinated with mixed pollen of LY29 and February orchid (ratio 3:1), and backcrossed for 4 generations (BC1 to BC4).

[0047] Flower color screening: The flower color types (orange, light pink, purple, pink) were counted after each generation of backcrossing. In the BC4 generation, orange accounted for 40%, light pink 30%, purple 20%, and pink 10%, and the flower color separation tended to be stable.

[0048] Crossbreeding of fertile plants with sterile plants: The pollen of fertile plants in the BC4 generation (accounting for 15%) was awarded to the corresponding sterile plants, and backcrossing was carried out for 4 consecutive generations. By the BC8 generation in 2024, the flower color type was stable (mutation rate <5%).

[0049] Step S6: Cold resistance and flower color verification

[0050] In September 2024, the final germplasm (BC8 generation) was sown in the experimental fields of Lanzhou New District and Tianshui Maiji District, with 3 replicates in each area and 100 plants planted in each replicate. The wintering rate was counted in March 2025, and the average wintering rates in the two places were 78.5% and 76.2% respectively, and the flower color type distribution was consistent with the BC8 generation (orange 42%, light pink 31%, purple 19%, pink 8%).

[0051] (III) Data and Effects

[0052] (1) Cold resistance: The wintering rate of BC8 generation in Lanzhou and Tianshui was ≥75%, which was significantly higher than that of the control spring colored flower varieties (wintering rate ≤30%);

[0053] (2) Flower color stability: After four consecutive generations of planting, the variation in the proportion of flower color types was less than 5%, and no fading or mixing occurred;

[0054] (3) Application effect: By 2025, 500 mu of planting area will be promoted in Zhangye City, Gansu Province, with an overwintering rate of 76.8%. During the flowering period, a colorful sea of ​​flowers will be formed, attracting more than 100,000 tourists and increasing the comprehensive output value by 40%.

[0055] Conclusion: This example successfully cultivated a new rapeseed germplasm with strong winter cold resistance and stable colored petal traits through directional screening, multi-generation backcrossing and distant hybridization technology, verifying the feasibility and practical application value of the method of the present invention.

[0056] In summary, the breeding of a strong winter-resistant colored flower rapeseed germplasm and its application of the present invention not only solves the problem that colored flower rapeseed in the northern arid and cold regions cannot safely overwinter, but also meets the market's diversified demand for ornamental rapeseed through the integration and stable expression of flower color genes. The breeding method and its application provide new germplasm resources and technical support for the development of landscape agriculture in high-altitude cold regions, and have significant economic and social benefits. In the future, with the further promotion and optimization of this technology, it is believed that more strong winter-resistant colored flower rapeseed varieties will emerge, injecting new vitality into the diversified development of my country's oil crop industry.

[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for breeding rapeseed germplasm with strong winter color flowers, characterized in that: The following steps are involved: S1: Self-pollination of radish cytoplasmic semi-winter rapeseed hybrid TY2288 to obtain segregating progeny seeds; S2: sowing the segregated progeny seeds in Lanzhou, Gansu, and selecting strong winter-tolerant plants that survive the winter and turn green; S3: The strong winter-resistant single plant selected in S2 was used as the female parent, and the mixed pollen of the strong winter-resistant rapeseed variety LY29 and February orchid was used for hybridization to obtain F1 generation seeds; S4: F1 seeds were sown in Lanzhou, Gansu, and male sterile plants that survived the winter were selected. The mixed pollen of LY29 and February orchid was used for backcrossing. The backcrossing was repeated for 4 generations to obtain a male sterile line with stable petal color and strong winter resistance. S5: The pollen of the fertile individual plants of the backcross offspring in S4 is transferred to the corresponding male sterile individual plants, and the backcross is continued for 4 generations until the flower color is stable; S6: The finally obtained colored rapeseed germplasm is sown in the northern arid and cold regions to verify that its overwintering rate is ≥ 75%, and it is determined to be a strong winter colored rapeseed germplasm.

2. The breeding method of a strong winter colored rapeseed germplasm according to claim 1, characterized in that: The petal colors include at least one of orange, light pink, purple, and pink.

3. The breeding method of a strong winter colored rapeseed germplasm according to claim 1, characterized in that: The northern arid and cold zone includes Lanzhou, Gansu and Tianshui, Gansu.

4. The method for breeding rapeseed germplasm with strong winter color flowers according to claim 1, characterized in that: The number of backcrossings in S4 is 4, and after each backcrossing, individual plants with differentiated petal colors are screened out.

5. Use of rapeseed germplasm with strong winter-resistant color flowers bred by the method as described in any one of claims 1 to 4 in autumn sowing in arid and cold regions in the north.

6. The use according to claim 1, characterized in that: The method comprises sowing the germplasm in arid and cold areas with a wintering rate of ≥75%, so as to realize large-scale planting of colored rapeseed.

7. A strong winter-resistant colored rapeseed germplasm, characterized in that: The petal is bred by the method described in any one of claims 1 to 4, and can stably express orange, light pink, purple and pink petal traits under the condition that the overwintering rate in the northern arid and cold regions is ≥ 75%.

8. The colored rapeseed germplasm according to claim 7, characterized in that: The cold resistance of the germplasm is significantly higher than that of spring and semi-winter colored flower rape varieties.

9. The colored rapeseed germplasm according to claim 7, characterized in that: The flower color of the germplasm remained stable after four consecutive planting generations.