Breeding of cytoplasmic male sterile line MS of flue-cured tobacco and its propagation method

Abstract

The application discloses a method for breeding and multiplying a flue-cured tobacco cytoplasmic male sterile line MS Yunyan 105, which takes the flue-cured tobacco cytoplasmic male sterile line MSG28 as a cytoplasmic sterile gene source, takes MSG28 as a female parent, takes the variety Yunyan 105 as a recurrent parent, is continuously backcrossed for six generations after hybridization, and is bred into a new type of cytoplasmic male sterile line MS Yunyan 105; takes the sterile line MS Yunyan 105 as the female parent, takes the maintainer line Yunyan 105 as the male parent, and hybridizes and multiplies to preserve the sterile line MS Yunyan 105; the flue-cured tobacco sterile line MS Yunyan 105 bred by the application has the advantages of stable sterility, strong comprehensive resistance, good appearance and internal quality of tobacco leaves, and coordinated chemical components, and provides a new excellent sterile line germplasm for flue-cured tobacco hybrid advantage utilization research work.

Description

Technical Field

[0001] This invention belongs to the field of tobacco genetics and breeding technology, specifically relating to the selection and propagation method of MS Yunyan 105, a cytoplasmic male sterile line for flue-cured tobacco. Background Technology

[0002] Flue-cured tobacco exhibits strong heterosis in terms of yield, disease resistance, growth period, and vigor. However, due to the lack of significant heterosis in leaf quality resulting from inter-varietal hybridization, the utilization of heterosis in flue-cured tobacco was once abandoned by tobacco breeders. In recent years, the scarcity of groundbreaking varieties bred in my country's flue-cured tobacco breeding program has led to a single dominant variety across the country, decreased varietal resistance, and widespread pest and disease damage, causing severe losses to my country's flue-cured tobacco production. Because of its strong resistance to adverse conditions and the short breeding cycle and rapid results of heterosis utilization, domestic breeders have begun to refocus on the utilization of heterosis in flue-cured tobacco, viewing it as a quick and effective breeding method.

[0003] The expression of heterosis is related to parental genetic diversity, increasing with increasing parental genetic distance. Therefore, breeding genetically diverse sterile lines of flue-cured tobacco and expanding the available germplasm resources are crucial foundational tasks for utilizing heterosis in flue-cured tobacco. Summary of the Invention

[0004] In response to the need for genetic diversity of sterile lines in the utilization of heterosis in flue-cured tobacco, this invention aims to provide a breeding and propagation method for MS Yunyan 105, a cytoplasmic male sterile line in flue-cured tobacco, to provide excellent sterile line germplasm for the utilization of heterosis in flue-cured tobacco and broaden the genetic basis for the utilization of heterosis in flue-cured tobacco.

[0005] To solve the above problems, the technical solution adopted in this invention is: the selection and propagation method of MS Yunyan 105, a cytoplasmic male sterile line for flue-cured tobacco. This method uses the sterile line MSG28 as the source of sterile cytoplasm and the variety Yunyan 105 as the recurrent parent to select the sterile line MS Yunyan 105; and uses the sterile line MS Yunyan 105 as the female parent and the maintainer line Yunyan 105 as the male parent to propagate the sterile line MS Yunyan 105.

[0006] The aforementioned breeding and propagation method of the flue-cured tobacco cytoplasmic male sterile line MS Yunyan 105 is as follows: The sterile line MS Yunyan 105 was obtained by the following steps: (1) Hybridization: Using the cytoplasmic male sterile line MSG28 of flue-cured tobacco as the female parent and the variety Yunyan 105 as the male parent, hybridization was carried out to obtain F1 seeds of male sterile hybrid combination. F1 seeds were mixed and harvested, and seed numbers were stored. (2) Continuous backcrossing: In the following year, male sterile hybrid combination F1 and Yunyan 105 were planted respectively. The male hybrid combination F1 was used as the female parent and Yunyan 105 was used as the backcross parent. BC1F1 seeds were obtained by backcrossing and the BC1F1 seeds were mixed and harvested. In subsequent years, combined with Hainan generation, Yunyan 105 was used as the recurrent parent and backcrossed with the backcross offspring for 5 consecutive generations until BC6F1 seeds were obtained. This was to achieve the goal of replacing the MSG28 cell nucleus with the Yunyan 105 cell nucleus and to cultivate the genetically stable, completely sterile cytoplasmic male sterile line MS Yunyan 105. The aforementioned breeding and propagation methods for the flue-cured tobacco cytoplasmic male sterile line MS Yunyan 105 are as follows: The propagation of the male sterile line MS Yunyan 105 adopts the following steps: (1) Planting: MS Yunyan 105 was used as the female parent and Yunyan 105 as the male parent. The parents were sown and transplanted at the same time according to the conventional method. The male parent and the female parent were planted at intervals of 1:4.

[0007] (2) Remove impurities and inferior plants: When the tobacco plants show buds, strictly remove impurities, inferior plants and diseased plants, and completely remove tobacco branches. Select typical plants according to the parent plant standards and bag them.

[0008] (3) Artificial pollination: When the corolla tip of the sterile line MS Yunyan 105 turns red but does not open, cut off the corolla tip with scissors or gently tear the corolla with your fingers to expose the pistil. Then, evenly apply the pollen of the maintainer line Yunyan 105 to the stigma of the sterile line pistil.

[0009] (4) Timely harvesting: Harvest each batch as it matures according to the order of hybridization and pollination. When the capsules turn brown, the seeds are mature and ready for harvest. The harvested seeds should be air-dried in a cool place, threshed, and stored in a low-temperature, dry, and sealed environment.

[0010] The sterile line MS Yunyan 105 developed in this invention has the following characteristics: The floral organ characteristics are as follows: The inflorescence characteristics of the sterile line MS Yunyan 105 are consistent with those of the maintainer line Yunyan 105. It is a compact inflorescence with a pink corolla. The pistil grows normally, while the stamens are degenerate, which means it is a stamen-degenerate sterile line.

[0011] The varietal characteristics are as follows: wide ecological adaptability and good varietal stability; strong comprehensive resistance, resistant to southern root-knot nematode disease, moderately resistant to black shank and bacterial wilt, moderately susceptible to red star disease, and susceptible to TMV; good appearance quality of tobacco leaves, light orange-yellow color, medium to strong chroma, and good oil content; harmonious chemical composition of tobacco leaves and good smoking quality.

[0012] Compared with existing technologies, the MS Yunyan 105 sterile tobacco line bred in this invention has the advantages of stable sterility, excellent agronomic traits, high yield and output value, good ease and tolerance to curing, good appearance and internal quality of tobacco leaves, and harmonious chemical composition. It provides a new and excellent sterile line germplasm for the research on the utilization of heterosis in flue-cured tobacco. Attached Figure Description

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein: Figure 1 This invention provides the breeding process for the cytoplasmic male sterile line MS Yunyan 105. Figure 2 Morphological image of MS Yunyan 105, a cytoplasmic male sterile line; Figure 3 This image shows the corolla characteristics of the cytoplasmic male sterile line MS Yunyan 105. Detailed Implementation

[0014] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0015] Example 1. The sterile line MS Yunyan 105 was obtained by the following method and steps: (1) Hybridization: Using the cytoplasmic male sterile line MSG28 of flue-cured tobacco as the female parent and the variety Yunyan 105 as the male parent, hybridization was carried out to obtain F1 seeds of male sterile hybrid combination. F1 seeds were mixed and harvested, and seed numbers were stored. (2) Continuous backcrossing: In the following year, male sterile hybrid combination F1 and Yunyan 105 were planted respectively. The male hybrid combination F1 was used as the female parent and Yunyan 105 was used as the backcross parent. BC1F1 seeds were obtained by backcrossing and the BC1F1 seeds were mixed and harvested. In subsequent years, combined with Hainan generation, Yunyan 105 was used as the recurrent parent and backcrossed with the backcross offspring for 5 consecutive generations until BC6F1 seeds were obtained. This was to achieve the goal of replacing the MSG28 cell nucleus with the Yunyan 105 cell nucleus and to cultivate the genetically stable, completely sterile cytoplasmic male sterile line MS Yunyan 105. The following methods and steps are used to propagate the sterile line MS Yunyan 105: (1) Planting: MS Yunyan 105 was used as the female parent and Yunyan 105 as the male parent. The parents were sown and transplanted at the same time according to the conventional method. The male and female parents were planted at intervals of 1:4.

[0016] (2) Remove impurities and inferior plants: When the tobacco plants show buds, strictly remove impurities, inferior plants and diseased plants, and completely remove tobacco branches. Select typical plants according to the parent plant standards and bag them.

[0017] (3) Artificial pollination: When the corolla tip of the sterile line MS Yunyan 105 turns red but does not open, cut off the corolla tip with scissors or gently tear the corolla with your fingers to expose the pistil. Then, evenly apply the pollen of the maintainer line Yunyan 105 to the stigma of the sterile line pistil.

[0018] (4) Timely harvesting: Harvest each batch as it matures according to the order of hybridization and pollination. When the capsules turn brown, the seeds are mature and ready for harvest. The harvested seeds should be air-dried in a cool place, threshed, and stored in a low-temperature, dry, and sealed environment.

[0019] MS Yunyan 105 was planted at the Jinhua flue-cured tobacco variety breeding and propagation base in Fenggang County, Zunyi City, Guizhou Province in 2023. The results are as follows: 1. Characteristics MS Yunyan 105 has a pyramidal plant shape with oblong leaves, green in color, and a medium stem-leaf angle. Its average field growth period is 126.7 days, from transplanting to budding stage is 63-65 days, and from transplanting to the maturity of the lower leaves is approximately 57 days. After topping, 23-25 ​​leaves are left. The plant height after topping is approximately 138cm, with a stem circumference of approximately 10cm. The lower leaves are 76.2cm x 39.4cm long and wide, the middle leaves are 73-75.6cm long and 34.6-36cm wide, and the top three leaves are approximately 50.5cm x 15cm long and wide.

[0020] 2. Disease resistance It is resistant to southern root-knot nematode disease, moderately resistant to black shank and bacterial wilt, moderately susceptible to red spot disease, and susceptible to TMV.

[0021] 3. Economic characteristics MS Yunyan 105 has an average yield of 115.64 kg per mu, with a top-grade tobacco ratio of 68.06% and a medium-grade tobacco ratio of 31.94%.

[0022] 4. Tobacco Leaf Quality 4.1 Appearance Quality MS Yunyan 105 tobacco leaves have bright, pure, and uniform colors in all parts of the first-cured tobacco leaf, with good oil content, moderate size, and good looseness. The lower tobacco leaves are lemon-colored to light orange, mainly light orange, with medium to strong color intensity. The middle tobacco leaves are light orange-yellow to golden yellow, mainly golden yellow, with medium to strong color intensity. The upper tobacco leaves are golden yellow with good color saturation and strong to strong color intensity.

[0023] 4.2 Main Chemical Components MS Yunyan 105 tobacco leaves from the central region have an average total sugar content of 31.8%, reducing sugar content of 27.4%, total alkaloid content of 1.8%, total nitrogen content of 1.7%, and potassium oxide content of 2.2%.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for breeding the flue-cured tobacco cytoplasmic male sterile line MS Yunyan 105, characterized in that: This method uses the sterile line MSG28 as the source of sterile cytoplasm, and the variety Yunyan 105 as the recurrent parent to breed the sterile line MS Yunyan 105; and uses the sterile line MS Yunyan 105 as the female parent and the maintainer line Yunyan 105 as the male parent to propagate the sterile line MS Yunyan 105. The sterile line MS Yunyan 105 was obtained through the following methods and steps: (1) Hybridization: Using the cytoplasmic male sterile line MSG28 of flue-cured tobacco as the female parent and the variety Yunyan 105 as the male parent, hybridization was carried out to obtain F1 seeds of male sterile hybrid combination. F1 seeds were mixed and harvested, and seed numbers were stored. (2) Continuous backcrossing: In the following year, male sterile hybrid combination F1 and Yunyan 105 were planted respectively. The male hybrid combination F1 was used as the female parent and Yunyan 105 was used as the backcross parent. BC1F1 seeds were obtained by backcrossing and the BC1F1 seeds were mixed and harvested. In subsequent years, combined with Hainan generation, Yunyan 105 was used as the recurrent parent and backcrossed with the backcross offspring for 5 consecutive generations until BC6F1 seeds were obtained. This was to achieve the goal of replacing the nucleus of MSG28 cells with the nucleus of Yunyan 105 cells, and to cultivate a genetically stable, completely sterile cytoplasmic male sterile line MS Yunyan 105.

2. The propagation method of MS Yunyan 105, a flue-cured tobacco cytoplasmic male sterile line bred as described in claim 1, is characterized in that... The following methods and steps are used to propagate the sterile line MS Yunyan 105: (1) Planting: MS Yunyan 105 was used as the female parent and Yunyan 105 was used as the male parent. The parents were sown and transplanted at the same time according to the conventional method. The male parent and the female parent were planted at intervals of 1:

4. (2) Remove impurities and inferior plants: When the tobacco plants are budding, strictly remove impurities, inferior plants and diseased plants, and completely remove tobacco branches. Select typical plants according to the parent plant standards and bag them. (3) Artificial pollination: When the corolla tip of the sterile line MS Yunyan 105 turns red but does not open, cut off the corolla tip with scissors or gently tear the corolla with your fingers to expose the pistil. Then, evenly apply the pollen of the maintainer line Yunyan 105 to the stigma of the sterile line pistil. (4) Timely harvesting: Harvest each batch as it matures according to the order of hybridization and pollination. When the capsules turn brown, the seeds are mature and ready for harvest. The harvested seeds should be air-dried in a cool place, threshed, and stored in a low-temperature, dry, and sealed environment.

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