A method for rapidly breeding new hybrid camellia varieties

Abstract

The present invention discloses a method for rapidly breeding new hybrid camellia varieties, belonging to the technical field of camellia plant breeding. The method of the present invention comprises the following technical steps: (1) hybrid seedling cultivation; (2) preliminary determination of hybrid seedlings; (3) hybrid seedling germination promotion; (4) rootstock treatment; (5) scion collection; (6) grafting; (7) disinfection and moisturizing; (8) flowering promotion; (9) flowering management; and (10) final determination of hybrid seedlings. The method of the present invention can effectively shorten the juvenile period of hybrid seedlings, achieve the transformation from vegetative growth to reproductive growth in a short period of time, enable hybrid seedlings to reach the flowering period as soon as possible, shorten breeding time, and improve breeding efficiency. Compared with traditional seedling hybrids that take 8 years to reach the flowering period, the method of the present invention can enable hybrid seedlings to reach the flowering period in approximately 4 years, greatly shortening the breeding period, and having great application value for rapidly breeding new hybrid camellia varieties.

Description

Technical Field

[0001] The invention belongs to the technical field of camellia plant breeding, and particularly relates to a method for rapidly breeding new hybrid camellia varieties. Background Art

[0002] Camellia japonica L. is an evergreen shrub or small tree of the genus Camellia in the family Theaceae. Native to China, Camellia prefers warm, humid environments, exhibits a degree of cold tolerance, and prefers fertile, loose, slightly acidic soil. Camellias come in a wide variety of colors, with the majority being red or pinkish, though white can also be found. Many of the flowers are double-petaled, making them highly ornamental. Their flowers also have hemostatic properties, and their seeds, used for oil extraction, possess significant economic value. my country, the distribution center of Camellia, boasts a rich collection of camellia germplasm. Camellia enthusiasts select and breed variants (such as bud and leaf mutations) from hybrid seedlings of the original Camellia species. Furthermore, through natural and artificial hybridization, many new camellia varieties with excellent ornamental qualities have been created.

[0003] Camellias grow slowly, making artificial hybridization a long and complex process. From the discovery of high-quality germplasm, collection and introduction, cultivation and domestication, propagation and utilization, to the identification of desirable traits, parent selection, and finally, detasseling and bagging for pollination, the process is lengthy. Furthermore, to create new varieties with high ornamental value, most hybrid combinations involve distant hybridization. Consequently, the parents often exhibit hybrid incompatibility, resulting in extremely low fruit set and few hybrid fruits. This hybrid incompatibility often leads to malformed or underdeveloped embryos in hybrid seeds, resulting in abortion and a low seedling success rate. Therefore, hybrid seeds obtained through artificial hybridization are extremely valuable. In most cases, hybrid progeny of camellia plants are identified by direct planting from seedlings. However, the time it takes for hybrid seedlings to emerge from juvenile stages and reach their first natural flowering and fruiting is long, taking 8 to 10 years. Therefore, hybrid seedlings must be allowed to grow naturally until they have left their juvenile stage and have begun to bloom before being identified and selected. This results in a very long breeding time and high production costs, which severely reduces the economic benefits of camellia production.

[0004] Therefore, how to shorten the childhood period of hybrid camellia seedlings, realize the transformation from vegetative growth to reproductive growth in a short period of time, make the hybrid seedlings reach the flowering period as soon as possible, shorten the breeding time and improve the breeding efficiency is the difficulty of the new camellia variety breeding technology. Summary of the Invention

[0005] In response to the above problems, the present invention provides a method for rapidly breeding new hybrid camellia varieties. Through the breeding processes of hybrid seedling cultivation, germination promotion, grafting and flowering promotion, the hybrid seedlings can reach the flowering period as soon as possible, shortening the breeding time of new varieties.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for rapidly breeding new hybrid camellia varieties comprises the following steps:

[0008] (1) Hybrid seedling cultivation: From October to November of the previous year, freshly harvested, pest-free, and plump mature camellia hybrid seeds were selected and placed in a seedling bag filled with a seedling medium for sowing. When the seeds developed into seedlings, the seedlings were transplanted to the field for planting to cultivate seedling hybrid seedlings.

[0009] (2) Preliminary determination of hybrid seedlings: The phenotypic characteristics of the cultivated seedlings are compared with those of the parents to preliminarily determine the authenticity of the hybrid seedlings; the phenotypic characteristics include leaf shape, leaf length, leaf width, leaf margin serrations, leaf buds and leaf bases;

[0010] (3) Hybrid seedling germination promotion: From January to April of the same year, when the hybrid seedlings grow to a height of 15-20 cm and a ground diameter of more than 0.5 cm, the hybrid seedlings are topped to promote germination. After that, the hybrid seedlings are irrigated with a compound fertilizer solution and sprayed with a sodium nitrophenolate solution every 10-15 days;

[0011] (4) Rootstock treatment: Select a camellia seedling container that is over 2 years old, growing well, and has a well-developed root system. Cut the main trunk 15 to 30 cm from the upper surface of the container as the rootstock. Make two parallel cuts along the edge of the rootstock from top to bottom, deep into the wood. Use the tip of the knife to pick open the bark to form a grafting site. Place the container seedling in a shade shed for later use before grafting.

[0012] (5) Scion collection: From November of the current year to February of the following year, collect pest-free, semi-lignified branches with full buds from hybrid seedlings as scions. Prune the scions to a length of 4 to 6 cm, and cut the lower end into a length of 1.2 to 1.5 cm, leaving two leaves and two buds or one leaf and one bud;

[0013] (6) Grafting: Place the cut scion into the grafting port, keep the cambium on one side of the scion aligned with the cambium of the stock, cover the bark of the stock on the reverse side of the scion, and then wrap and tie the grafting port with black grafting film;

[0014] (7) Disinfection and moisturizing: After the grafting is completed, the entire plant is sprayed with fungicide for disinfection, and then the roots are soaked with water. A ziplock bag is used to cover the scion and the grafting point to moisturize the scion and the grafting point, and then the bag is sealed so that the scion and the grafting point remain in the ziplock bag;

[0015] (8) Flower promotion: In March or April after one year of grafting and cultivation, before the grafted hybrid seedlings sprout, cover the substrate on the upper surface of the container with a film 2 to 3 days in advance, and then apply different concentrations of paclobutrazol and ethephon hormone solutions to the roots of the plants three times on a sunny day, with an interval of 10 to 15 days between each application. Apply 1 to 1.5 L of hormone solution to each plant each time, and cover the container with the film after application.

[0016] (9) Management during flowering period: After the hybrid seedlings have flower buds, spray water mist on the plant leaves and surrounding environment regularly in the morning and evening to keep the humidity of the plant's growth environment at 50-70%. Use 1000-1500 times diluted Huaduoduo No. 2 to irrigate the roots. Use 800-1000 mg / L gibberellin to spray the flower buds once a week, spraying 5-6 times.

[0017] (10) Final confirmation of hybrid seedlings: After the hybrid seedlings bloom, the hybrid seedlings are compared with the parents in flowering characteristics for two consecutive years to finally determine the authenticity of the hybrid seedlings; the flowering characteristics include flowering period, flower shape, flower color and number of petals.

[0018] Furthermore, in step (8), the hormone solution is applied as follows: 150-200 ppm paclobutrazol is applied in the first drench, 800-1000 ppm ethephon is applied in the second drench, and 40-50 ppm paclobutrazol is applied in the third drench.

[0019] Furthermore, in step (8), the method of applying the hormone solution can also be: applying 1500-2000 ppm of ethephon in the first drench, applying 80-100 ppm of paclobutrazol in the second drench, and applying 1200-1500 ppm of ethephon in the third drench.

[0020] Furthermore, in step (7), the fungicide is carbendazim, mancozeb or thiophanate-methyl with a weight concentration of 0.2-0.5%; when the ziplock bag is sealed, 1 / 4-1 / 5 of the seal is left unsealed.

[0021] Furthermore, in step (6), during the grafting, the ambient temperature in the shade shed is adjusted to 16-18°C, and the surface temperature of the matrix in the container is adjusted to 20-23°C.

[0022] Furthermore, in step (3), the weight concentration of the compound fertilizer aqueous solution is 0.5-1%; the weight concentration of the sodium nitrophenolate solution is 1.5-2%, and the solution is diluted 6000-8000 times before application.

[0023] Furthermore, in step (1), a layer of coarse river sand or pebbles with a thickness of 15 to 20 cm is laid on the bottom of the seedling bag as a drainage layer, and then a seedling matrix with a thickness of 20 to 30 cm, which is composed of fine river sand and vermiculite in a volume ratio of 3 to 4:1, is filled on the drainage layer.

[0024] Furthermore, in step (1), the seedling culture medium is dried before bagging, and then a mixed solution prepared by 40-50 mg / L gibberellic acid solution and 90-100 mg / L ABT No. 6 in a volume ratio of 1-2:1 is fully mixed with the dried seedling culture medium, and a 0.3-0.5% by weight concentration of ferrous sulfate solution is used to adjust the pH value of the seedling culture medium to 5.5-6.5.

[0025] Furthermore, in step (1), the camellia hybrid seeds are derived from the following hybrid combinations of camellia varieties: fragrant flower oil-tea camellia (♂) × common golden camellia (♀), fragrant flower oil-tea camellia (♂) × Tam Island golden camellia (♀), Vietnamese stem-clasping camellia (♂) × Wantian red flower oil-tea camellia (♀).

[0026] Furthermore, in step (4), the varieties of the camellia container seedlings are fragrant flower oil tea, common oil tea, and hairy purple camellia; the rootstock treatment requires that the diameter of the trunk cut off 15 to 30 cm from the upper surface of the container is more than 1.5 cm.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0028] 1. The present invention effectively shortens the juvenile stage of hybrid seedlings through hybrid seedling cultivation, hybrid seedling germination promotion, grafting, and flowering promotion, achieving the transition from vegetative growth to reproductive growth in a short period of time, allowing hybrid seedlings to reach the flowering stage as quickly as possible, shortening breeding time and improving breeding efficiency. Compared to traditional seedling hybrids that take eight years to reach flowering, the present invention enables hybrid seedlings to reach flowering in approximately four years, significantly shortening the breeding time and having great application value for the rapid development of new hybrid camellia varieties.

[0029] 2. In the process of promoting flowering, the present invention uses hormone solutions of different concentrations of paclobutrazol and ethephon alternately and in combination. Paclobutrazol has the effects of delaying plant growth, inhibiting stem elongation, shortening internodes, promoting plant tillering, promoting flower bud differentiation, and increasing plant stress resistance; ethephon has the effects of promoting plant stress resistance, inhibiting plant growth, and promoting early flowering of plants. By inhibiting the nutritional growth of hybrid seedlings, it further promotes reproductive growth and promotes the differentiation of flower buds, thereby promoting the early flowering of subsequent hybrid seedlings.

[0030] 3. Since both paclobutrazol and ethephon can promote flower bud differentiation, in the process of promoting flowering of the present invention, paclobutrazol is used at most twice. Reducing the number of times paclobutrazol is used, and paclobutrazol and ethephon are used alternately, which can effectively avoid the phenomenon of leaf curling and internode shortening caused by excessive use of paclobutrazol in hybrid seedlings. Paclobutrazol has a long-lasting efficacy. If it is applied to the roots once in the same year, the efficacy can last for 3 to 5 years, effectively promoting the stability of flowering. At the same time, after the flower buds appear in the hybrid seedlings, using Huaduoduo No. 2 to irrigate the roots can supplement phosphorus and potassium fertilizer nutrients, and using gibberellins to spray the flower buds can effectively prolong the flowering period by more than one month, increase the flower shape, and make the flower color brighter, which is conducive to better comparing the flowering characteristics of the hybrid seedlings with those of the parents, further determining the authenticity of the hybrid seedlings, and screening out excellent hybrid germplasm.

[0031] 4. The present invention disinfects the plant and moisturizes the scion after grafting, which can prevent the infection of the plant by pathogens, improve the resistance of the plant to diseases, and promote wound healing. When moisturizing, a self-sealing bag is used, and 1 / 4 to 1 / 5 is left unsealed, so that the excess sap flowing out of the grafting port is conveniently discharged from the unsealed port, and the grafting port, scion, and rootstock are prevented from becoming moldy, resulting in grafting failure. At the same time, a black film grafting film is used to tie the grafting port, so that the grafting port quickly produces hormones under dark conditions, which can cause a large number of cells in the grafting port to reproduce, form callus tissue, promote the healing of the grafting port, and thus improve the grafting survival rate of hybrid seedlings.

[0032] 5. The present invention adopts container seedlings of excellent rootstock varieties such as fragrant flower tea, common tea, and hairy purple tea as rootstocks. The large rootstock container seedlings have strong activity and strong resistance to adversity, and have strong adaptability to natural environments such as drought, waterlogging, and high temperature. The scion and rootstock of the hybrid seedlings can quickly heal and sprout new shoots, the grafting survival rate is high, and the sprouted new shoots grow rapidly. At the same time, the rootstock container seedlings are used, which is convenient for whole-process management, especially maintaining the temperature of the matrix in the container and preventing rain erosion, which is conducive to shortening breeding costs.

[0033] 6. In the process of cultivating seedlings of hybrid seedlings, the present invention uses a seedling matrix composed of fine river sand and vermiculite. The matrix is water-permeable and breathable, and also contains certain nutrients. At the same time, according to the slightly acidic growth environment preferred by camellia plants, the seedling matrix is adjusted to a slightly acidic environment by spraying ferrous sulfate solution to promote the germination of hybrid seeds. In addition, a mixed solution of gibberellic acid and ABT No. 6 is fully mixed with the dried seedling matrix to promote the growth of the hybrid seedling root system. The root system germinates more and is thicker, promoting the rapid growth of seedlings, and laying a foundation for the spikelet resource for the subsequent grafting of hybrid seedlings as soon as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a diagram showing that the male parent in Example 1 is Camellia oleifera.

[0035] Figure 2 The female parent in Example 1 is a figure of common Camellia chrysantha.

[0036] Figure 3 This is a photo of the on-site flowering promotion of the common Camellia chrysantha hybrid seedlings in Example 1.

[0037] Figure 4 This is a picture of the flower buds of the common Camellia chrysantha hybrid seedlings in Example 1.

[0038] Figure 5 It is a flowering diagram of the common golden camellia hybrid seedlings in Example 1.

[0039] Figure 6 This is a diagram showing that the male parent is Camellia oleifera in Example 2.

[0040] Figure 7 The female parent in Example 2 is the Camellia chrysantha of Tam Island.

[0041] Figure 8 This is a photo of the on-site flowering promotion of the Tam Island Camellia chrysantha hybrid seedlings in Example 2.

[0042] Figure 9 This is a flowering diagram of the Tam Island Camellia chrysantha hybrid seedlings in Example 2.

[0043] Figure 10 The male parent in Example 3 is a Vietnamese camellia.

[0044] Figure 11 The female parent in Example 3 is the Wantian safflower tea oil plant.

[0045] Figure 12 This is a photo of the Wantian safflower oil-tea hybrid seedlings in Example 3 at the seedling stage four months after grafting.

[0046] Figure 13 This is a diagram of the flowering promotion of the Wantian safflower oil-tea hybrid seedlings in Example 3.

[0047] Figure 14 These are the leaves and buds of the common Camellia chrysantha hybrid seedlings in Comparative Example 1.

[0048] Figure 15 These are the leaves and flowering pictures of the Tam Island Camellia chrysantha hybrid seedlings in Comparative Example 2. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below through examples. These examples are only used to illustrate the present invention and do not limit the scope of protection of the present invention.

[0050] Example 1

[0051] A method for rapidly breeding new hybrid camellia varieties comprises the following steps:

[0052] (1) Hybrid seedling cultivation: In October 2016, common Camellia chrysantha hybrid seeds (male parent is Camellia oleifera and female parent is Camellia chrysantha) with no pests and diseases and full appearance were selected, and the seeds were placed in seedling bags filled with seedling matrix for sowing. A layer of coarse river sand or pebbles with a thickness of 15 cm was laid on the bottom of the seedling bag as a drainage layer, and then a seedling matrix with a thickness of 20 cm and composed of fine river sand and vermiculite in a volume ratio of 3:1 was filled on the drainage layer. The seedling matrix was dried before bagging, and then a mixed solution prepared by 45 mg / L gibberellic acid solution and 90 mg / L ABT No. 6 in a volume ratio of 1:1 was fully mixed with the dried seedling matrix, and the pH value of the seedling matrix was adjusted to 6 with a weight concentration of 0.3% ferrous sulfate solution. When the seeds developed into seedlings, the seedlings were transplanted to the field for planting to cultivate seedling hybrid seedlings;

[0053] (2) Preliminary determination of hybrid seedlings: The phenotypic characteristics of the cultivated hybrid seedlings in leaf shape, leaf length, leaf width, leaf margin serrations, leaf buds and leaf bases were compared with those of the parents to preliminarily determine the authenticity of the hybrid seedlings;

[0054] (3) Hybrid seedling germination promotion: In April 2017, when the hybrid seedlings grew to a height of 20 cm and a ground diameter of 0.8 cm, the hybrid seedlings were topped to promote germination. Thereafter, every 10 days, the hybrid seedlings were irrigated with a 0.5% weight concentration of compound fertilizer aqueous solution and sprayed with a 6000-fold dilution of a 1.5% weight concentration of sodium nitrophenolate solution to promote germination and growth;

[0055] (4) Rootstock treatment: Select a container seedling of Camellia oleifera that is over 2 years old, has good growth and a well-developed root system. Cut the trunk with a diameter of 2 cm at a distance of 20 cm from the upper surface of the container as the rootstock. Make two parallel cuts along the edge of the rootstock from top to bottom, deep into the wood. Use the tip of the knife to pick open the cortex to form a grafting site. Place the container seedling in a shade shed for use before grafting.

[0056] (5) Scion collection: In December 2017, semi-lignified branches with no pests and diseases and full buds were collected from hybrid seedlings as scions. The scions were trimmed to a length of 6 cm, and the lower end was cut into a 1.5 cm incision, leaving one leaf and one bud;

[0057] (6) Grafting: Adjust the ambient temperature in the shade shed to 16°C and the surface temperature of the substrate in the container to 20°C. Place the cut scion into the grafting port, aligning the cambium on one side of the scion with the cambium on the rootstock. Cover the rootstock bark on the reverse cut of the scion, and then wrap and tie the grafting port with black grafting film.

[0058] (7) Disinfection and moisturizing: After the grafting is completed, the entire plant is sprayed with 0.4% carbendazim by weight for disinfection, and then the roots are soaked with water. The scion and grafting point are covered with a ziplock bag to moisturize the bag, and then sealed, leaving 1 / 4 of the bag unsealed so that the scion and grafting point remain in the ziplock bag;

[0059] (8) Flower promotion: In April 2019, before the grafted hybrid seedlings germinated, the substrate on the upper surface of the container was covered with a film 2 days in advance to isolate rainwater. Then, different concentrations of paclobutrazol and ethephon hormone solutions were applied to the root part of the plant three times on a sunny day. The first time, 1500ppm ethephon was applied, the second time, 100ppm paclobutrazol was applied, and the third time, 1200ppm ethephon was applied. Each time, 1L of hormone solution was applied to each plant. After applying the hormone solution, the film was covered again. The flower promotion process is as follows: Figure 3 As shown;

[0060] (9) Flowering period management: In July 2019, after the hybrid seedlings have obvious flower buds, Figure 4 As shown, spray water mist on the leaves of the plant and the surrounding environment regularly in the morning and evening, maintain the humidity of the plant growth environment at 70%, use 1200 times diluted Huaduoduo No. 2 to irrigate the roots to supplement phosphorus and potassium fertilizer nutrients, and spray the flower buds with 800mg / L gibberellin once a week for 6 times, which can effectively extend the flowering period by more than one month, enlarge the flower shape, and make the flower color brighter;

[0061] (10) Final confirmation of hybrid seedlings: After the hybrid seedlings bloom, the flowering characteristics of the hybrid seedlings and their parents in terms of flowering period, flower shape, flower color and number of petals are compared for two consecutive years to finally determine the authenticity of the hybrid seedlings.

[0062] The characteristics of the new hybrid varieties of common Camellia chrysantha and its parents are compared, as shown in Table 1 below:

[0063] Table 1 Comparison of the characteristics of new hybrid varieties of Camellia chrysantha and their parents

[0064]

[0065] From Table 1, we can see that the new hybrid varieties of common Camellia chrysantha ( Figure 5 )'s leaf color and shape are inherited from the mother plant Camellia chrysantha ( Figure 2 ) characteristics, the flower color inherits the characteristics of both parents, the leaf color is lighter, and the flower shape tends to be more like the male parent Camellia oleifera ( Figure 1 ), the flowering period is between the two parents.

[0066] Example 2

[0067] A method for rapidly breeding new hybrid camellia varieties comprises the following steps:

[0068] (1) Hybrid seedling cultivation: In October 2018, the hybrid seeds of Camellia chrysantha (male parent: Camellia oleifera) with no diseases and insect pests and full appearance were selected, and the seeds were placed in a seedling bag filled with a seedling medium for sowing. A layer of coarse river sand or pebbles with a thickness of 20 cm was laid on the bottom of the seedling bag as a drainage layer. Then, a seedling medium with a thickness of 25 cm and composed of fine river sand and vermiculite in a volume ratio of 4:1 was filled on the drainage layer. The seedling medium was dried before bagging, and then a mixed solution prepared by 50 mg / L gibberellic acid solution and 95 mg / L ABT No. 6 in a volume ratio of 1:1 was fully mixed with the dried seedling medium, and a 0.5% weight concentration of ferrous sulfate solution was used to adjust the pH value of the seedling medium to 6.5. When the seeds developed into seedlings, the seedlings were transplanted to the field for planting to cultivate seedling hybrid seedlings;

[0069] (2) Preliminary determination of hybrid seedlings: The phenotypic characteristics of the cultivated hybrid seedlings in leaf shape, leaf length, leaf width, leaf margin serrations, leaf buds and leaf bases were compared with those of the parents to preliminarily determine the authenticity of the hybrid seedlings;

[0070] (3) Hybrid seedling germination promotion: In February 2019, when the hybrid seedlings grew to a height of 18 cm and a ground diameter of 0.7 cm, the hybrid seedlings were topped to promote germination. Thereafter, every 15 days, the hybrid seedlings were irrigated with a 1% weight concentration of compound fertilizer aqueous solution and sprayed with a 2% weight concentration of sodium nitrophenolate solution 8000 times diluted to promote germination and growth;

[0071] (4) Rootstock treatment: Select common Camellia oleifera container seedlings that are over 2 years old, growing well, and have a well-developed root system. Cut the trunk with a diameter of 1.5 cm at a distance of 30 cm from the upper surface of the container as the rootstock. Make two parallel cuts along the edge of the rootstock from top to bottom, deep into the wood. Use the tip of the knife to pick open the cortex to form a grafting site. Place the container seedlings in a shade shed for use before grafting.

[0072] (5) Scion collection: In January 2020, collect semi-lignified branches with no pests and diseases and full buds from hybrid seedlings as scions. Prune the scions to a length of 6 cm, cut the lower end into a 1.2 cm incision, and retain two leaves and two buds.

[0073] (6) Grafting: Adjust the ambient temperature in the shade shed to 18°C and the surface temperature of the substrate in the container to 22°C. Place the cut scion into the grafting port, keeping the cambium on one side of the scion aligned with the cambium on the rootstock. Cover the rootstock bark on the reverse cut of the scion, and then wrap and tie the grafting port with black grafting film.

[0074] (7) Disinfection and moisturizing: After the grafting is completed, the entire plant is sprayed with 0.4% by weight concentration of thiophanate-methyl for disinfection, and then the roots are soaked with water. The scion and the grafting point are covered with a ziplock bag to moisturize the bag, and then the bag is sealed, leaving 1 / 5 of the bag unsealed so that the scion and the grafting point remain in the ziplock bag;

[0075] (8) Flower promotion: In April 2021, before the grafted hybrid seedlings germinate, cover the substrate on the upper surface of the container with a film 3 days in advance to isolate rainwater, and then apply different concentrations of paclobutrazol and ethephon hormone solutions to the root part of the plant three times on a sunny day. The first time, 150ppm paclobutrazol was applied, the second time, 1000ppm ethephon was applied, and the third time, 40ppm paclobutrazol was applied. Each time, 14 days passed. Each plant was sprayed with 1.5L of hormone solution each time. After spraying the hormone solution, cover the film again. The flower promotion process is as follows: Figure 8 As shown;

[0076] (9) Flowering period management: In June 2021, after the hybrid seedlings have flower buds, spray water mist on the plant leaves and the surrounding environment regularly in the morning and evening. The humidity of the plant growth environment is maintained at 60%. Use 1000 times diluted Huaduoduo No. 2 to irrigate the roots to supplement phosphorus and potassium fertilizer nutrients. Use 900 mg / L gibberellin to spray the flower buds once a week for 6 times. This can effectively extend the flowering period by more than one month, increase the flower shape, and make the flower color more colorful.

[0077] (10) Final confirmation of hybrid seedlings: After the hybrid seedlings bloom, the flowering characteristics of the hybrid seedlings and their parents in terms of flowering period, flower shape, flower color and number of petals are compared for two consecutive years to finally determine the authenticity of the hybrid seedlings.

[0078] The characteristics of the new Tam Island Camellia chrysantha variety and its parents are compared, as shown in Table 2 below:

[0079] Table 2 Comparison of the characteristics of the new hybrid varieties of Camellia chrysantha and their parents

[0080]

[0081] As shown in Table 2, the new hybrid varieties of Camellia chrysantha ( Figure 9 ) inherited the leaf color, leaf shape and flower color from the female plant Camellia chrysantha ( Figure 7 ) characteristics, the flower shape tends to be similar to the male parent Camellia oleifera ( Figure 6 ), the flowering period is between the two parents.

[0082] Example 3

[0083] A method for rapidly breeding new hybrid camellia varieties comprises the following steps:

[0084] (1) Hybrid seedling cultivation: In November 2019, the hybrid seeds of Wantian safflower oil-tea (the male parent is Vietnamese camellia and the female parent is Wantian safflower oil-tea) without pests and diseases and with full appearance were selected, and the seeds were placed in a seedling bag filled with seedling medium for sowing. A layer of coarse river sand or pebbles with a thickness of 15 cm was laid on the bottom of the seedling bag as a drainage layer, and then a seedling medium with a thickness of 25 cm and composed of fine river sand and vermiculite in a volume ratio of 3:1 was filled on the drainage layer. The seedling medium was dried before bagging, and then a mixed solution prepared by 40 mg / L gibberellic acid solution and 100 mg / L ABT No. 6 in a volume ratio of 2:1 was fully mixed with the dried seedling medium, and the pH value of the seedling medium was adjusted to 5.5 with a weight concentration of 0.4% ferrous sulfate solution. When the seeds developed into seedlings, the seedlings were transplanted to the field for planting to cultivate seedling hybrid seedlings;

[0085] (2) Preliminary determination of hybrid seedlings: The phenotypic characteristics of the cultivated hybrid seedlings in leaf shape, leaf length, leaf width, leaf margin serrations, leaf buds and leaf bases were compared with those of the parents to preliminarily determine the authenticity of the hybrid seedlings;

[0086] (3) Hybrid seedling germination promotion: In April 2020, when the hybrid seedlings grew to a height of 15 cm and a ground diameter of 0.5 cm, the hybrid seedlings were topped to promote germination. Thereafter, every 10 days, the hybrid seedlings were sprinkled with a 0.8% weight concentration of compound fertilizer aqueous solution and sprayed with 8000 times the weight concentration of 1.5% sodium nitrophenolate solution to promote germination and growth;

[0087] (4) Rootstock treatment: Select Camellia oleifera container seedlings that are over 2 years old, growing well, and have a well-developed root system. Cut the trunk with a diameter of 2.3 cm at a distance of 15 cm from the upper surface of the container as the rootstock. Make two parallel cuts along the edge of the rootstock from top to bottom, deep into the wood. Use the tip of the knife to pick open the bark to form a grafting site. Place the container seedlings in a shade shed for use before grafting.

[0088] (5) Scion collection: In February 2021, collect semi-lignified branches with no pests and diseases and full buds from hybrid seedlings as scions. Prune the scions to a length of 4 cm, cut a 1.2 cm incision at the lower end, and retain one leaf and one bud;

[0089] (6) Grafting: Adjust the ambient temperature in the shade shed to 18°C and the surface temperature of the substrate in the container to 22°C. Place the cut scion into the grafting port, keeping the cambium on one side of the scion aligned with the cambium on the rootstock. Cover the rootstock bark on the reverse cut of the scion, and then wrap and tie the grafting port with black grafting film.

[0090] (7) Disinfection and moisturizing: After the grafting is completed, the entire plant is sprayed with 0.4% Zineb by weight for disinfection, and then the roots are soaked with water. The scion and the grafting point are covered with a ziplock bag to moisturize the bag, and then sealed, leaving 1 / 4 of the bag unsealed so that the scion and the grafting point remain in the ziplock bag;

[0091] (8) Flower promotion: In April 2022, before the grafted hybrid seedlings germinate, cover the substrate on the upper surface of the container with a film 2 days in advance to isolate rainwater. Then, on a sunny day, apply different concentrations of paclobutrazol and ethephon hormone solutions to the root part of the plant three times. The first time, 2000ppm ethephon was applied, the second time, 80ppm paclobutrazol was applied, and the third time, 1200ppm ethephon was applied. Each time, 15 days apart, 1.2L of hormone solution was applied to each plant each time. After applying the hormone solution, cover the container with the film. The flower promotion process is as follows: Figure 13 As shown;

[0092] (9) Flowering period management: In July 2022, after the hybrid seedlings have flower buds, spray water mist on the plant leaves and the surrounding environment regularly in the morning and evening. The humidity of the plant growth environment is maintained at 70%. Use 1000 times the solution of Huaduoduo No. 2 to irrigate the roots to supplement phosphorus and potassium fertilizer nutrients. Use 1000 mg / L gibberellin to spray the flower buds once a week for 6 times. This can effectively extend the flowering period by more than one month, increase the flower shape, and make the flower color more colorful.

[0093] (10) Final confirmation of hybrid seedlings: After the hybrid seedlings bloom, the flowering characteristics of the hybrid seedlings and their parents in terms of flowering period, flower shape, flower color and number of petals are compared for two consecutive years to finally determine the authenticity of the hybrid seedlings.

[0094] The characteristics of the new hybrid variety of Wantian safflower oil-tea camellia were compared with those of its parents, as shown in Table 3 below:

[0095] Table 3 Comparison of the characteristics of the new hybrid varieties of Wantian safflower oil-tea tea and their parents

[0096]

[0097]

[0098] From Table 3, we can see that the new hybrid varieties of Wantian red camellia oil ( Figure 12 )'s leaf color, leaf shape, and flower color are inherited from both parents ( Figure 11 、 Figure 12 ) characteristics, the leaf base does not embrace the stem, which is different from the male parent, Camellia claspingii, which has a base clasping stem ( Figure 11 ), the color of young leaves tends to be closer to the father ( Figure 12 ), the flowering period is between the two parents.

[0099] Comparative Example 1

[0100] The difference between Comparative Example 1 and Example 1 is that in the process of promoting flowering in step (8), the hormone solution applied for the first, second and third times is 100 ppm of paclobutrazol, and the rest of the cultivation process and conditions are the same as those in Example 1. Figure 14 As shown, the leaves of the plants showed obvious signs of phytotoxicity, such as falling off, curling, and shortening of internodes.

[0101] Comparative Example 2

[0102] The difference between Comparative Example 2 and Example 2 is that in the process of promoting flowering in step (8), the first, second and third application of hormone solution in Comparative Example 1 is 150ppm paclobutrazol, and the rest of the cultivation process and conditions are the same as those in Example 2. Figure 15 As shown, the leaves of the plants showed obvious signs of phytotoxicity, such as falling off, curling, and shortening of internodes.

[0103] Comparative Example 3

[0104] In October 2014, common golden camellia hybrid seeds (the male parent was fragrant camellia oleifera and the female parent was common golden camellia) with no pests and diseases and full appearance were selected, and the seeds were placed in seedling bags filled with seedling substrate for sowing. A layer of coarse river sand or pebbles with a thickness of 15 cm was laid on the bottom of the seedling bag as a drainage layer, and then a seedling substrate with a thickness of 20 cm and composed of fine river sand and vermiculite in a volume ratio of 3:1 was filled on the drainage layer. The seedling substrate was dried before bagging, and then a mixed solution prepared by 45 mg / L gibberellic acid solution and 90 mg / L ABT No. 6 in a volume ratio of 1:1 was fully mixed with the dried seedling substrate, and the pH value of the seedling substrate was adjusted to 6 with a weight concentration of 0.3% ferrous sulfate solution. When the seeds developed into seedlings, the seedlings were transplanted to the field for planting, and the growth management of the seedling hybrid seedlings was carried out according to traditional methods. The plants bloomed from December 2022 to January of the following year.

[0105] The grafting and flowering promotion effects of the hybrid camellia seedlings in Examples 1-3 and Comparative Examples 1-3 were statistically analyzed, and the relevant data are shown in Table 1 below.

[0106] Table 3 Grafting and flowering status of camellia hybrid seedlings

[0107]

[0108] As shown in Table 3, the grafting survival rate of hybrid camellia seedlings obtained by the method of the present invention is over 95%. The hybrid seedlings reach the flowering stage in about 4 years. After flower promotion, the leaves of the plants grow normally, with no obvious leaf curling, shedding, shortened internodes, or other phytotoxic phenomena. The plants normally develop buds and bloom. In Comparative Examples 1 and 2, although the flowering period is the same as that in Examples 1-3 of the present invention, paclobutrazol hormone solution was used three times in a row to promote flower promotion in Comparative Examples 1 and 2. After flower promotion, the leaves show obvious phytotoxic phenomena such as shedding, curling, and shortened internodes. In Comparative Example 3, hybrid camellia seedlings were cultivated according to traditional methods without grafting or flower promotion. The plants grew slowly and took 8 years to reach the flowering stage.

[0109] Compared to Comparative Example 3, the present invention enables hybrid seedlings to reach flowering sooner, reaching flowering approximately four years earlier, allowing for rapid development of new varieties. Compared to Comparative Examples 1 and 2, the present invention enables plants to maintain normal leaf growth, bud formation, and flowering during the flowering period. This demonstrates that the present invention significantly shortens breeding time and allows for rapid development of new hybrid camellia varieties.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for rapidly breeding new hybrid camellia varieties, characterized in that: The following steps are involved: (1) Hybrid seedling cultivation: From October to November of the previous year, select freshly harvested, pest-free, and plump mature camellia hybrid seeds, place the seeds in a seedling bag filled with a seedling medium, and sow them. When the seeds develop into seedlings, transplant the seedlings to the field to cultivate seedling hybrid seedlings. The hybrid camellia seeds are derived from the following hybrid combinations of camellia varieties: fragrant flower oil camellia (♂) × common golden camellia (♀), fragrant flower oil camellia (♂) × Tam Island golden camellia (♀), Vietnamese stem-clasping camellia (♂) × Wantian red flower oil camellia (♀); (2) Preliminary determination of hybrid seedlings: Compare the phenotypic characteristics of the cultivated seedlings with those of the parents to preliminarily determine the authenticity of the hybrid seedlings; (3) Hybrid seedling germination promotion: From January to April of the same year, when the hybrid seedlings grow to a height of 15-20 cm and a ground diameter of more than 0.5 cm, the hybrid seedlings are topped to promote germination. After that, the hybrid seedlings are irrigated with a compound fertilizer solution and sprayed with a sodium nitrophenolate solution every 10-15 days. (4) Rootstock treatment: Select a camellia seedling container that is over 2 years old, has good growth and a well-developed root system. Cut the main trunk 15 to 30 cm from the upper surface of the container as the rootstock. Make two parallel cuts along the edge of the rootstock from top to bottom, deep into the wood. Use the tip of the knife to pick open the bark to form a grafting site. Place the container seedling in a shade shed for use before grafting. (5) Scion collection: From November of the current year to February of the following year, collect pest-free, semi-lignified branches with full buds from hybrid seedlings as scions. Prune the scions to a length of 4 to 6 cm, and cut the lower end into a length of 1.2 to 1.5 cm. Keep two leaves and two buds or one leaf and one bud. (6) Grafting: Place the cut scion into the grafting port, keep the cambium on one side of the scion aligned with the cambium on the rootstock, cover the rootstock bark on the reverse cut of the scion, and then wrap and tie the grafting port with black grafting film; (7) Disinfection and moisturizing: After the grafting is completed, spray the entire plant with fungicide for disinfection, then soak the roots with water, use a ziplock bag to cover the scion and grafting point to moisturize, and then seal the bag so that the scion and grafting point remain in the ziplock bag; (8) Flower promotion: In March or April after one year of grafting and cultivation, before the grafted hybrid seedlings sprout, cover the substrate on the upper surface of the container with a film 2 to 3 days in advance, and then apply different concentrations of paclobutrazol and ethephon hormone solutions to the root part of the plant three times on a sunny day, with an interval of 10 to 15 days between each application. Each plant is sprayed with 1 to 1.5 L of hormone solution each time, and the film is covered again after the application of the hormone solution. The method of applying the hormone solution is: 150 to 200 ppm paclobutrazol is applied for the first application, 800 to 1000 ppm ethephon is applied for the second application, and 40 to 50 ppm paclobutrazol is applied for the third application. (9) Management during flowering period: After the hybrid seedlings have flower buds, spray water mist on the plant leaves and surrounding environment regularly in the morning and evening to keep the humidity of the plant's growth environment at 50-70%. Use 1000-1500 times diluted Huaduoduo No. 2 to irrigate the roots. Use 800-1000 mg / L gibberellin to spray the flower buds once a week, and spray 5-6 times. (10) Final confirmation of hybrid seedlings: After the hybrid seedlings bloom, the flowering characteristics of the hybrid seedlings will be compared with those of the parents for two consecutive years to finally determine the authenticity of the hybrid seedlings.

2. The method for rapidly breeding new hybrid camellia varieties according to claim 1, characterized in that: In step (8), the hormone solution may be applied as follows: 1500-2000 ppm ethephon is applied in the first drench, 80-100 ppm paclobutrazol is applied in the second drench, and 1200-1500 ppm ethephon is applied in the third drench.

3. The method for rapidly breeding new hybrid camellia varieties according to claim 1, characterized in that: In step (7), the fungicide is carbendazim, mancozeb or thiophanate-methyl with a weight concentration of 0.2-0.5%; when the ziplock bag is sealed, 1 / 4-1 / 5 of the seal is left unsealed.

4. The method for rapidly breeding new hybrid camellia varieties according to claim 1, characterized in that: In step (6), during the grafting, the ambient temperature in the shade shed is adjusted to 16-18°C, and the surface temperature of the matrix in the container is adjusted to 20-23°C.

5. The method for rapidly breeding new hybrid camellia varieties according to claim 1, characterized in that: In step (3), the weight concentration of the compound fertilizer aqueous solution is 0.5-1%; the weight concentration of the sodium nitrophenolate solution is 1.5-2%, and the solution is diluted 6000-8000 times before application.

6. The method for rapidly breeding new hybrid camellia varieties according to claim 1, characterized in that: In step (1), a layer of coarse river sand or pebbles with a thickness of 15 to 20 cm is laid on the bottom of the seedling bag as a drainage layer, and then a seedling matrix with a thickness of 20 to 30 cm, which is composed of fine river sand and vermiculite in a volume ratio of 3 to 4:1, is filled on the drainage layer.

7. The method for rapidly breeding new hybrid camellia varieties according to claim 6, characterized in that: In step (1), the seedling culture medium is dried before bagging, and then a mixed solution prepared by 40-50 mg / L gibberellic acid solution and 90-100 mg / L ABT No. 6 in a volume ratio of 1-2:1 is fully mixed with the dried seedling culture medium, and a ferrous sulfate solution with a weight concentration of 0.3-0.5% is used to adjust the pH value of the seedling culture medium to 5.5-6.

5.

8. The method for rapidly breeding new hybrid camellia varieties according to claim 1, characterized in that: In step (4), the varieties of the camellia container seedlings are fragrant camellia, common camellia, and hairy purple camellia; the rootstock treatment requires that the diameter of the trunk cut off 15 to 30 cm from the upper surface of the container is more than 1.5 cm.

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