Method for raising seedlings of idesia polycarpa by field cutting in autumn and winter

Abstract

The invention discloses a field cutting seedling raising method for idesia in autumn and winter, and relates to the technical field of plant breeding, the method comprises the following steps: in late October or late December, cutting current-year idesia branches as cutting slips into uniform stem segments, reserving axillary buds on each stem segment, flatly cutting an upper notch, obliquely cutting a lower notch on a single side, inserting the cutting slips into a seedbed, and cutting into seedlings; the soil humidity is maintained at 70%-80%, and normal growth is carried out under natural conditions. According to the method, factors such as different cutting periods, cutting depths, cutting stock plant parts, cutting thickness, cutting length, lower notch shapes, root growth promoting agent (variety and concentration) treatment and the like are systematically researched, a technical combination most suitable for field cutting seedling raising of idesia in autumn and winter is optimized, and a set of efficient idesia cutting asexual propagation method is established. The method not only provides a feasible industrial seedling raising technology for asexual propagation of the idesia polycarpa, but also has important practical significance for popularization of improved varieties of the idesia polycarpa and industrial quality and efficiency improvement.

Description

Technical field:

[0001] The invention relates to the technical field of tree asexual propagation, and in particular to a method for raising seedlings of Castanopsis truncatum by cutting in the field in autumn and winter. Background technology:

[0002] Idesia polycarpa Maxim., a deciduous tree belonging to the genus Idesia in the family Idesiaceae, is known for its tolerance to drought, strong stress resistance, and wide adaptability. It is a typical high-yielding woody oilseed tree. Its kernel oil content is as high as 35%-45%, with linoleic acid comprising approximately 75%-80% of the oil. Rich in vitamin E, phytosterols, and polyphenols, it possesses both nutritional and industrial value. It also regulates unsaturated fatty acid metabolism and lowers serum cholesterol levels, while also possessing antioxidant and anti-cancer properties. Known as the "oil depot on the tree," its flesh accounts for 62.3% of its total mass, while seeds comprise 37.6%. The whole dried fruit has an oil content of 35.0%-39.36%, with an average oil content of 36.71%, making it a valuable reserve for oil. It has a wide range of applications in food, healthcare, pharmaceuticals, and industrial oils, and holds promising market prospects.

[0003] The development of the Chinese tallow tree industry is still in its infancy, with the cultivation of high-quality seedlings, in particular, a core area of ​​research and a key technology. However, large-scale cultivation of Chinese tallow trees faces two major bottlenecks: first, the low survival rate of seed propagation seedlings. Because the seeds are small and covered in a waxy layer, their natural germination rate is low. Second, the sex of Chinese tallow tree seedlings cannot be controlled, and the offspring do not fully retain the desirable traits of the parent plant. Distinguishing male and female plants is difficult during the seedling stage, and it takes 5–7 years for seedlings to reach the first fruiting stage before sex can be determined. This leads to an imbalance in the distribution of male and female plants in the orchard, with approximately half of the male plants failing to produce fruit, seriously impacting high and stable yields. Therefore, the successful establishment of asexual propagation technology for Chinese tallow trees is crucial to addressing the challenges of producing high-quality seedlings. Compared to grafting and tissue culture, cutting propagation offers advantages such as ease of operation, low cost, and stable genetic traits, making it particularly suitable for large-scale, industrialized field production. Research on cuttings of Castanopsis truncatum has made some progress, but the rooting rate of cuttings taken in spring and summer is relatively low. For example, research by Tan Qin et al. showed that the rooting rate of spring hardwood cuttings is only 30.00%–36.70%. Softwood cuttings are affected by multiple factors, including the type of hormone (e.g., NAA, IBA), treatment concentration (100-800 mg / L), cutting location (base preferred over mid-section), and substrate ratio. Chen Yaobing et al.'s study of Castanopsis truncatum softwood cuttings showed that in summer, the survival rate of softwood cuttings treated with 200 mg / kg NAA under fully enclosed conditions was 32.60%. While root cuttings can achieve rooting rates of 80%–90%, they require stringent cutting age (2–5 years) and diameter (0.5–3.0 cm), limiting their large-scale application. Maintaining the necessary light, temperature, and humidity for cuttings in the hot and humid summer months requires extensive environmental control facilities, increasing maintenance costs. In summary, existing cutting propagation techniques for Castanopsis truncatum still have some shortcomings, such as: the limited seedling raising season, mostly in spring and summer, labor shortages, low cutting survival rates, and high seedling raising costs. The production cycle is long and the plant is susceptible to pests and diseases; the cuttings and substrate need to be disinfected, and a series of complex management and maintenance issues, such as the need to construct shade nets, urgently need further optimization and improvement. How to achieve rapid, low-cost, robust growth, and industrializable seedling raising methods for Castanopsis truncatum artificial cultivation and propagation is an urgent problem to be solved.

[0004] Based on this, the present invention focuses on the optimization of the cutting seedling technology of Castanopsis chinensis. By systematically studying the effects of different cutting periods, cutting depths, cutting mother plant positions, cutting thickness, cutting length, lower incision shape and root promoter (type, concentration) treatment on rooting rate, survival rate and seedling growth, it aims to establish an efficient cutting propagation technology system for Castanopsis chinensis, and provide technical support for the preservation of Castanopsis chinensis germplasm resources, sex-controlled seedling cultivation and industrial promotion. Summary of the invention:

[0005] The present invention aims to provide a method for raising seedlings of Castanopsis truncatum by field cuttings in autumn and winter. By systematically studying the effects of cutting period, cutting depth, mother plant position, cutting thickness, cutting length, lower incision shape, type and concentration of root-promoting agents on rooting rate, survival rate and seedling growth, a set of efficient field cutting propagation technology system for Castanopsis truncatum in autumn and winter is established, providing technical support for breeding of Castanopsis truncatum varieties, preservation of germplasm resources and industrial promotion.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A method for raising seedlings of Castanopsis truncatula by cuttings in the field in autumn and winter comprises the following steps:

[0008] S1. Determine the cutting time: The cutting time is late October or late December;

[0009] S2. Establishment of seedbed;

[0010] S3. Cutting selection: Choose strong, semi-lignified branches of the current year, with no disease and full buds;

[0011] S4. Cutting processing: Cut the cuttings into uniform stem segments, without retaining leaves in each segment, and make the cuttings smooth;

[0012] S5. Propagation: insert the cuttings into the seedbed. After the cuttings are completed, water until they are completely penetrated.

[0013] S6. Management after planting: maintain soil moisture and weed regularly.

[0014] The field cutting seedling raising method of Castanopsis truncatum L. is carried out in southern China, more preferably in Changsha, Hunan Province, and preferably in late October.

[0015] The seedbed soil in step S2 is at least one of Quaternary red clay and loess.

[0016] In step S3, branches in the middle and upper parts of the mother plant are selected as cuttings. The upper 1 / 3 of the branch is the upper part, the middle 1 / 3 is the middle part, and the lower 1 / 3 is the lower part.

[0017] In step S4, the thickness of the cuttings does not exceed 1.6 cm, preferably 0.6-1.0 cm; the length of the cuttings is 8-20 cm, preferably 13-15 cm.

[0018] In step S4, the upper incision of the cutting is flat, and the lower incision is single-sided beveled (the entire incision is a bevel), the bevel angle of the incision is 40-50 degrees, and the incision is smooth.

[0019] In step S5, before cutting, the cuttings are dipped in a 750-850 mg / L IBA solution for 3-5 seconds, preferably an 800 mg / L IBA solution, or the cuttings are directly cut without IBA treatment.

[0020] The cutting depth in step S5 is 2 / 3-4 / 5 of the cutting, preferably 10 cm.

[0021] The cutting angle in step S5 is straight cutting, and the cutting spacing is 15cm-20cm.

[0022] In step S6, the soil moisture is maintained at 70%-80%.

[0023] In summary, the present invention has the following beneficial effects:

[0024] (1) The present invention breaks the seasonal limitation of conventional Castanopsis truncatula cuttings seedling cultivation, and constructs a Castanopsis truncatula field cutting technology system suitable for large-scale production in autumn and winter. For example: in late October, more than 50% of the strong cuttings germinate in the same year, and more than 50% of the cuttings take root in the same year after germination. New leaves fall off after the low temperature in January of the following year, and new leaves grow again in March. The rooting rate is the highest in the following year. From the perspective of phenology, autumn and winter cuttings can enable the cuttings to complete callus induction and root primordium differentiation during the low-temperature dormancy period, and start rooting and germination simultaneously when the ground temperature stabilizes and rises in the spring of the following year, which is conducive to avoiding the "false life" risk of spring cuttings. Moreover, although the low temperature environment after October will delay the rooting process, the lower temperature can effectively inhibit the activity of pathogenic microorganisms, reduce the frequency of disinfection and the investment in disease prevention and control, and at the same time, the labor demand during the dormancy period is misaligned with the peak of agricultural work, which is conducive to reducing labor costs and improving management efficiency.

[0025] (2) The present invention shows that the cutting depth is an important factor affecting the rooting characteristics of Castanopsis truncatula. With the increase of cutting depth, the rooting rate and survival rate show a trend of first increasing and then decreasing. The cuttings with a length of 15 cm reach the maximum value when the cutting depth is 10 cm, while the rooting rate is 0% when the cutting depth is 5 cm. When the cutting depth is 10 cm, the cuttings can fully contact the soil and maintain suitable moisture and temperature conditions, which provides a stable environment for the formation and development of root primordia. A deeper cutting depth helps to reduce water evaporation on the cutting surface, maintain the physiological activity inside the cutting, and thus promote rooting, but too deep a cutting depth may lead to insufficient oxygen supply at the base of the cutting.

[0026] In the cutting diameter selection test, cuttings with a diameter of 0.6-1.0 cm had the highest rooting rate, longest root length, the greatest number of roots, the tallest plant height, and the thickest ground diameter. Thinner cuttings have fewer nutrients and may be depleted before new leaves unfold, failing to provide a sufficient foundation for growth. These cuttings are less resistant and prone to death during the cutting process, resulting in a lower rooting rate. Cuttings that are too thick and lignified have poor rooting results.

[0027] (3) The present invention found that although there was no significant difference in rooting rate and survival rate between the single-sided bevel treatment and the double-sided bevel treatment at the lower incision of the cutting, the root deviation rate of the double-sided bevel treatment was higher than that of the single-sided bevel treatment, and the base structure was relatively fragile. Considering the root growth effect and the convenience of operation, the single-sided bevel treatment was preferred in the Castanopsis chinensis cutting seedling cultivation.

[0028] (4) The present invention found that the root promoter IBA helps improve the rooting rate, survival rate, and plant height of Castanopsis truncatum cuttings; the root promoter NAA helps increase the average number of roots and average root length of cuttings; and the root promoter ABT helps increase the ground diameter and leaf size of Castanopsis truncatum cuttings. However, high concentrations of NAA and ABT can lead to decreased rooting rate and survival rate of cuttings. Therefore, in actual production, an 800 mg / L IBA solution should be used as a root promoter for Castanopsis truncatum cuttings.

[0029] (5) When all factors of the present invention are at the optimal level, the survival rate of Castanopsis can reach more than 71%. The operation is simple, the cuttings are easy to transport, and the cost is low. It is a seedling raising technology suitable for the asexual reproduction of Castanopsis and can be promoted industrially. In short, the present invention optimizes the most suitable technical combination for Castanopsis container cutting seedling raising by systematically studying different cutting periods and cutting treatment methods, and establishes a set of efficient Castanopsis asexual reproduction methods. This method not only provides a practical and feasible industrial seedling raising technology for the asexual reproduction of Castanopsis, but also has important practical significance for the promotion of Castanopsis improved varieties and the improvement of industry quality and efficiency. Description of the drawings:

[0030] Figure 1 These are photos of different stages of the rooting process of Tung oil tree cuttings in Example 1 of the present invention;

[0031] Figure 1 A: Callus tissue is produced by the incision at the base; Figure 1 B: adventitious roots emerge; Figure 1 CD: adventitious root elongation; Figure 1 E: rooting in the bark; Figure 1 F: root growth period; Figure 1 G: Cuttings germinated; Figure 1 H: The number of sprouting leaves increases; Figure 1 I: Axillary buds begin to shoot and grow; Figure 1 J: Axillary buds grow into shoots; Figure 1 KL: Root growth of cutting seedlings in October of the following year; Figure 1 MO: the initial growth condition of the cuttings in the seedbed; Figure 1 P: Some cuttings planted in late October have axillary buds that sprout new leaves in the same year, but the new leaves fall off due to low temperatures the following year, and new leaves grow in March; Figure 1 QR: Growth of the cuttings in the seedbed in October of the following year.

[0032] Figure 2 This is a photo of the rooting and aboveground growth of the Castanopsis truncatula cuttings in late April of the following year in Example 1 of the present invention;

[0033] Figure 2 A: cuttings with a thickness of less than 0.5 cm; Figure 2 B: Cuttings of the treatment group with a diameter of 0.6-1.0 cm; Figure 2 C: cuttings of the treatment group with a diameter of 1.1-1.5 cm; Figure 2 D: Cuttings with flat cut bottom; Figure 2 E: The lower incision is a double-sided bevel cutting of the cuttings; Figure 2 F: The lower incision is a cutting with a single-sided bevel treatment; Figure 2 GI: Figure 2 DF corresponds to the growth of the aboveground part of the cuttings.

[0034] Figure 3 These are photos of the growth of the roots and leaves of the Castanopsis truncatula cuttings treated with different hormones in Example 1 of the present invention in late July of the following year;

[0035] Figure 3 A:CK; Figure 3 B: NAA 500 mg / L; Figure 3 C: ABT 800mg / L; Figure 3 D: ABT 1000mg / L; Figure 3 E: IBA 500 mg / L; Figure 3 F: NAA 800mg / L; Figure 3 G: NAA 1000mg / L; Figure 3 H: ABT 500mg / L; Figure 3 I: IBA 1000mg / L; Figure 3 J: IBA 800mg / L.

[0036] Figure 4 This is a photo of the root growth of Tung oilseed cuttings when transplanting in Example 1 of the present invention;

[0037] Figure 4 A: Cutting seedlings of the treatment group with a diameter of 0.6-1.0 cm; Figure 4B: Cutting seedlings of the treatment group with a length of 13-15 cm; Figure 4 C: Cutting seedlings of the NAA 800 mg / L treatment group; Figure 4 D: Cutting seedlings of the IBA 800 mg / L treatment group; Figure 4 E: Cutting seedlings of the ABT 800 mg / L treatment group; Figure 4 F: Cutting seedlings of the lower incision single-side oblique cutting treatment group; Figure 4 G: Cutting seedlings of the double-sided bevel cut treatment group; Figure 4 H: Cutting seedlings of the lower incision flat cutting treatment group; Figure 4 I: Cutting seedlings of the treatment group with a diameter of 1.1-1.5 cm; Figure 4 J: Cutting seedlings of the treatment group with a length of 8-10 cm.

[0038] Figure 5 This is the growth status of the Castanopsis trees that were grafted in late October in October of the following year.

[0039] Figure 6 This is a photo of the fruiting of one-year-old Castanopsis chinensis cuttings in May of the following year after being planted in spring. Specific implementation method:

[0040] The present invention will be further described in detail below with reference to the examples, which do not limit the present invention.

[0041] Example 1

[0042] A method for raising seedlings of Castanopsis truncatula by cuttings in the field in autumn and winter comprises the following steps:

[0043] Experiment on the effects of different cutting periods, cutting depths, cutting diameters, cutting lengths, mother plant positions, lower incision types, and root promoters (types and concentrations) on the survival rate of Castanopsis chinensis cutting seedlings in the field.

[0044] The experimental site for this example was located in Changsha, Hunan Province (111°53′-114°15′ E, 27°51′-28°41′ N). The average annual temperature is 17.2°C, with extreme low temperatures occurring primarily in January (average temperature 5.20°C). Annual rainfall is 1452 mm, with precipitation concentrated in June (224.20 mm) and the lowest in December (49.70 mm). The climate is characterized by distinct four seasons, with simultaneous rainy and rainy seasons. Spring is wet and rainy, the transition period between summer and autumn is dry, and severe winters are short, maintaining a mild and humid climate throughout the year. The experiment used a single-factor experimental design to study different grafting periods (temperature range of 16-21℃ on October 28, 2023, temperature range of 8-22℃ on November 28, 2023, temperature range of 7-14℃ on December 29, 2023, and temperature range of 12-26℃ on March 28, 2024); different cutting depths (5cm, 7.5cm, 10cm, 12cm); different cutting mother plants (base, middle and upper parts of semi-lignified branches of the current year); different cutting thicknesses (thin cuttings no more than 0.5cm, medium cuttings 0.6cm-1. 0cm and thick cuttings 1.1cm-1.5cm); different cutting lengths (8-10cm, 13-15cm, 18-20cm); different lower incision shapes (flat cut, single-sided bevel cut, double-sided bevel cut); different root promoter treatments (IBA, NAA, ABT rooting powder No. 6) These seven factors affect the survival and growth of container-grown cuttings of Castanopsis chinensis seedlings. The most suitable cutting time and optimal cutting combination for container-grown cuttings of Castanopsis chinensis seedlings were screened out. Each of the above cuttings was repeated 3 times, with a total of 90 cuttings per treatment, and the average value was taken. The following operations were performed in sequence:

[0045] S1. Cutting time is determined: Cutting time is from October 2023 to March 2024;

[0046] S2. Establishing cutting beds: Use loess to make seedbeds, install 2-3 sets of adjustable micro-sprinkler irrigation devices on each bed, with the nozzle height at least 1m above the substrate surface, and maintain the field water holding capacity of the substrate at 70-85%;

[0047] S3. Cutting selection: Select the base, middle, and upper parts of the current-year semi-lignified branches of Castanopsis tung oil tree; the cuttings should be thin (no more than 0.5 cm), medium (0.6 cm-1.0 cm), and thick (1.1 cm-1.5 cm) thick. Cuttings should be healthy, pest-free, and have a low degree of lignification. The branches should be disease-free.

[0048] S4. Cuttings processing: Cut the cuttings into uniform small segments, without retaining leaves in each segment, and make the cuttings smooth; the cutting lengths are 8-10cm, 13-15cm, and 18-20cm respectively; the upper cutting of the cuttings is flat, and the lower cutting adopts flat cutting, single-sided bevel cutting, or double-sided bevel cutting, and the cutting is smooth;

[0049] S5. Rooting agent treatment: Three levels of rooting agent were set (IBA, NAA, ABT rooting powder No. 6) and three levels of rooting agent concentration (500 mg / L, 800 mg / L, and 1000 mg / L). The base of the cuttings was quickly dipped in the rooting agent. A control group was treated with water. There were 10 treatments in total, with 30 cuttings per treatment, and three replicates.

[0050] S6. Propagation of cuttings: Insert cuttings into the seedbed using the direct insertion method; the cutting depths are 5 cm, 7.5 cm, 10 cm, and 12 cm, respectively; the cutting spacing is 15 cm-20 cm. After the cuttings are completed, water the soil thoroughly to ensure that the base of the cuttings is in close contact with the substrate;

[0051] S7. Management after planting: Maintain soil moisture at 70%-80%, conduct pest and disease inspections every week, and regularly remove weeds, fallen leaves and other debris.

[0052] The experiment started in late October 2023 and statistics were collected in July 2024: seedling height (cm), ground diameter (cm), average number of leaves, root growth indicators, rooting rate, survival rate, etc.

[0053] The experiment adopted a single-factor experimental design. When one of the factors changed, the other factors were fixed as follows: cuttings on October 28, 2023; cutting depth of about 10 cm; the upper part of the cutting with a terminal bud; cutting thickness 0.6 cm-0.8 cm; cutting length 13-15 cm; single-sided bevel cut; treatment with 800 mg / L IBA solution.

[0054] Table 1 Effects of different cutting treatments on the rooting rate and survival rate of Castanopsis chinensis cuttings in the field in autumn and winter

[0055]

[0056]

[0057] Table 1 shows that cuttings planted in late October had the highest rooting rate (68.33%) and survival rate (63.33%), which were 17.10%, 13.90%, and 20.60% higher than those planted in late November, late December, and late March of the following year; 22.60%, 18.80%, and 26.70% higher, respectively. Cuttings planted at a depth of 10 cm had the highest rooting rate (70.00%) and survival rate (65.00%), which were 50.00%, 56.00%, and 82.60% and 95.00% higher than those planted at depths of 7.5 cm and 10 cm, respectively. The rooting rate and survival rate of the 5 cm shallow cutting treatment were both 0%. Cuttings from the upper part of the plant had the highest rooting rate (71.67%) and survival rate (65.00%), exceeding those from the base and middle parts by 48.30%, 19.45%, and 9.21%, respectively, and 5.5%. Cuttings with a diameter of 0.6-1.0 cm performed best, with a rooting rate (70.00%) and survival rate (66.67%) that were 61.96%, 27.30%, and 90.48%, respectively, higher than those from thin cuttings (no larger than 0.5 cm) and thick cuttings (1.1-1.5 cm). Cuttings 13-15 cm in length had the highest rooting rate (70.00%) and survival rate (66.67%), which were 13.50% and 44.80% higher than those 8-10 cm and 25.00% and 61.30% higher, respectively. Cuttings treated with a single-sided bevel cut at the bottom had better rooting results, with a rooting rate of 71.67% and a survival rate of 68.33%. Cuttings treated with an 800 mg / L IBA solution showed the best rooting performance, with a rooting rate of 76.67% and a survival rate of 71.67%.

[0058] In summary, the best time to propagate Castanopsis truncatum cuttings in the field in autumn and winter is in late October. Select robust, pest-free, current-year branches from the upper part of the tree. Cut them at an angle on one side, with a diameter of 0.6–1.0 cm and a length of 13–15 cm. Treat them with an 800 mg / L IBA solution and insert them vertically into the substrate at a depth of 10 cm. This combination is the optimal treatment for achieving the highest rooting and survival rates for Castanopsis truncatum cuttings in the field in autumn and winter.

[0059] Table 2 Effects of different cutting treatments on the root growth of Castanopsis chinensis cuttings in the field in autumn and winter

[0060]

[0061]

[0062] Note: The rooting rate and survival rate of cuttings with a cutting depth of 5 cm are both 0, so there is no later root growth data, which is represented by...

[0063] Table 2 shows that the average root number (4.99), average root diameter (1.23 mm), average root length (11.18 cm), and maximum root length (28.42 cm) of seedlings taken in late October were significantly greater than those taken at the other three cutting depths. Among the different cutting depths, the 10 cm cutting depth showed significant advantages in average root number (5.43 cm), average root diameter (1.2 cm), average root length (12.52 cm), and maximum root length (29.79 cm). The upper portion of the mother plant had the largest average root diameter (1.23 mm) and longest root length (12.13 cm). The middle portion had the longest root length (29.64 cm) and the highest average root number (4.99). When the cutting diameter was between 0.6 and 1.0 cm, the average root number (4.68) and maximum root length (28.82 cm) reached optimal levels. The 1.1-1.5 cm diameter treatment group demonstrated outstanding root quality, with the highest average root diameter (1.17 mm) and average root length (11.52 cm) among all groups. Results from treatments with varying cutting lengths showed that 13-15 cm cuttings significantly outperformed in average root number, average root diameter, average root length, and longest root length, with values ​​of 4.68, 1.16 mm, 11.47 cm, and 30.22 cm, respectively. Different incision shapes significantly affected root growth. The single-sided bevel treatment had the highest average root number (4.68), the largest diameter (1.12 mm), and the longest root length (31.50 cm). The double-sided bevel treatment had the longest average root length (10.89 cm).

[0064] Under different root promoter treatments, IBA at 1000 mg / L achieved the highest average root number (5.07 roots) and average root length (13.28 cm). The highest average root diameter and longest root length were achieved at 800 mg / L, reaching 1.39 mm and 34.42 cm, respectively. NAA at 1000 mg / L achieved the highest average root number (5.67 roots) and the longest root length (30.12 cm). The highest average root diameter (1.15 mm) was achieved at 500 mg / L, and the highest average root length (12.27 cm) was achieved at 800 mg / L. Using ABT as a root growth promoter, the average number of roots was the largest (4.55) and the average root diameter was the largest (1.25 mm) under the ABT 800 mg / L treatment; the average root length was the longest (11.3 cm) under the ABT 500 mg / L treatment; and the longest root length was the best (31.22 cm) under the ABT 1000 mg / L treatment.

[0065] In summary, the combination of late October, a cutting depth of 10 cm, and a cutting length of 13–15 cm achieved optimal root growth indicators such as average root number and average root diameter. Upper and middle branches, medium-thick and thick spikes, single-sided and double-sided bevel cutting, and different root-promoting agents exhibited complementary advantages in specific root growth indicators. Therefore, the combination of late October as the cutting date, 10 cm as the cutting depth, and 13–15 cm as the cutting length is recommended as the optimal technical solution for field propagation of Castanopsis truncatula in autumn and winter. Other factors (branch position, diameter, incision method, and root-promoting agent) can be flexibly configured based on actual production practices and resource conditions.

[0066] Table 3 Effects of different treatments on the growth of Castanopsis chinensis cuttings in the field in autumn and winter

[0067]

[0068]

[0069]

[0070] Note: The rooting rate and survival rate of cuttings with a cutting depth of 5 cm are both 0, so there is no cutting growth data, which is represented by...

[0071] The data in Table 3 (all seedlings were planted in late October) show that by April 10 of the following year, seedlings planted at a cutting depth of 7.5 cm had the highest plant height, at 9.42 cm, 29.80% and 84.30% taller than those planted at 10 cm and 12 cm, respectively. Seedlings planted at a cutting depth of 10 cm had the thickest ground diameter (8.34 mm). Seedlings planted at cutting depths of 7.5 cm and 10 cm had the most leaves (2.33). Seedlings planted with cuttings at the top had the highest plant height (7.52 cm), 11.10% and 8.00% taller than those at the middle and base, respectively. Cuttings planted at the base had the thickest ground diameter (8.97 mm), 18.80% and 8.90% taller than those at the top and base, respectively. Cuttings with cutting lengths of 18-20 cm had the highest plant height (9.03 cm), 85.00% and 22.70% taller than those with cutting lengths of 8-10 cm and 13-15 cm, respectively. Different cutting diameters, lower incision shapes, and root-promoting agents had no significant effect on plant height or leaf number in T. truncatum cuttings.

[0072] By June 3rd of the following year, cuttings planted at a depth of 7.5 cm had the highest plant height (27.13 cm), 11.80% and 27.20% taller than those planted at 10 cm and 12 cm, respectively. Cuttings planted at a depth of 10 cm had the most leaves (18.00), 28.60% and 50.00% higher than those planted at 7.5 cm and 12 cm, respectively. Cuttings planted at the top had the highest plant height (28.98 cm) and the most leaves (18.33), 25.30% and 7.70% taller than those planted at the base, respectively. The base had the largest diameter (9.82 mm), 6.70% and 7.70% thicker than the top and middle sections, respectively. Cuttings with a cutting diameter of 0.6-1.0 cm had the tallest plant height (23.98 cm) and the most leaves (19.33), which were 64.70% taller and 31.60% taller than those with cutting diameters of 0-0.5 cm and 99.90% and 26.10% taller, respectively. Cuttings with a cutting diameter of 1.1-1.5 cm had the thickest ground diameter of 11.27 mm, which was 64.00% taller and 19.30% taller than those with cutting diameters of 0-0.5 cm and 0.6-1.0 cm. Cuttings with cutting lengths of 13-15 cm were superior in terms of plant height, ground diameter, and leaf number, reaching 26.57 cm, 9.74 mm, and 20.33 leaves, respectively. These figures were 16.60% higher than those with cutting lengths of 8-10 cm, 48.10% higher than those with cutting lengths of 18-20 cm, and 6.50% higher than those with cutting lengths of 18-20 cm, and 74.20% and 69.40% higher than those with cutting lengths of 18-20 cm. Cuttings with a single-sided bevel cut had the highest plant height (26.87 cm) and the largest ground diameter (9.33 mm), 10.90% higher than those with a flat cut, and 3.80% higher than those with a flat cut, respectively. Cuttings with a single-sided bevel cut also had the highest leaf number (20.67 leaves), 19.30% higher than those with a flat cut. The cuttings in the IBA 800 mg / L treatment group had the highest plant height (29.37 cm), the largest diameter at ground level (10.62 mm), and the most leaves (27.00), which were 15.30%, 17.50%, and 28.90% higher than the CK, respectively. The NAA 500 mg / L treatment group had the highest plant height (25.57 cm) and the most leaves (19.00). Both the NAA 800 mg / L treatment group (24.53 cm) and the NAA 1000 mg / L treatment group (22.13 cm) were lower than the CK. The NAA 1000 mg / L treatment group had the largest diameter at ground level (9.08 mm), slightly higher than the CK (9.04 mm). The ABT 800 mg / L treatment group had the highest plant height (24.70 cm), but was 3.1% lower than the CK. The ABT 1000 mg / L treatment group had the largest diameter (9.42 mm) and the largest number of leaves (23.33), which were 4.20% and 22.80% higher than those of CK, respectively.

[0073] By July 30 of the following year, cuttings planted at a depth of 10 cm had superior plant height, ground diameter, and leaf count, reaching 43.36 cm, 11.76 mm, and 32.00 leaves, respectively. These indicators were 19.30% and 27.80% higher than those planted at 7.5 cm, 7.50% and 17.40% higher, and 26.30% and 74.60% higher than those planted at a depth of 12 cm. Cuttings planted at the top had the highest plant height (46.90 cm) and the most leaves (35.00), 11.10% and 11.70% higher than those planted at the base, respectively. The base had the largest ground diameter (11.97 mm), 12.70% higher than the middle. The cuttings in the 0.6-1.0 cm cutting diameter group had the highest plant height of 42.26 cm and the most leaves of 32.00, which were 52.90% and 21.10% higher than those in the 0-0.5 cm and 1.1-1.5 cm cutting diameter groups, respectively. The cuttings in the 1.1-1.5 cm cutting diameter group had the largest ground diameter of 13.75 mm, which was 64.50% and 15.90% higher than those in the 0-0.5 cm and 0.6-1.0 cm cutting diameter groups, respectively. Cuttings with cutting lengths of 13-15 cm showed advantages in plant height (42.36 cm), ground diameter (11.86 mm), and leaf number (33.00), exceeding those with cutting lengths of 8-10 cm by 23.80%, 57.50% by 21.90%, 26.20% by 21.40%, and 50.00% by 18-20 cm, respectively. Cuttings with single-sided beveled cuttings showed the highest plant height (42.66 cm), the largest ground diameter (11.78 mm), and the greatest leaf number (33.00), exceeding those with flat cutting by 13.90%, 9.50%, and 17.90%, respectively. There were no significant differences in these three indicators between single-sided and double-sided beveled cuttings (P>0.05). The IBA 800 mg / L treatment dominated in terms of plant height, ground diameter, and leaf number, reaching 49.53 cm, 12.31 mm, and 40.33 leaves, respectively, which were 18.10%, 13.60%, and 28.70% higher than those in the CK. The NAA 500 mg / L treatment achieved the highest plant height (43.20 cm), ground diameter (10.85 mm), and leaf number (34.67 leaves), which decreased with increasing NAA concentration. The ABT 1000 mg / L treatment achieved the highest ground diameter (11.22 mm) and the highest leaf number (35.67 leaves), which were 3.4% and 13.9% higher than those in the CK, respectively. The ABT 800 mg / L treatment achieved the highest plant height (45.30 cm), but the ABT 1000 mg / L treatment had the lowest plant height (40.47 cm).

[0074] In summary, the best time to propagate Castanopsis truncatum cuttings in the field during autumn and winter is in late October. Use cuttings from Castanopsis truncatum branches with a diameter of 0.6-1.0 cm and a length of 13-15 cm. Cuttings are cut obliquely at the base, treated with 800 mg·L⁻¹ of IBA, and then inserted vertically into the substrate to a depth of 10 cm. This combination maintains optimal plant height, ground diameter, and leaf number.

[0075] Table 4 Comparison of photosynthesis in leaves of Castanopsis chinensis seedlings under different cutting methods

[0076]

[0077] Note: The rooting rate and survival rate of cuttings with a cutting depth of 5 cm are both 0, so there is no leaf photosynthesis data, which is represented by...

[0078] The data in Table 4 show that the net photosynthetic rate Pn values ​​of the cuttings in the group with cuttings in late October, cutting depth of 10 cm, cuttings on the top, cuttings with a thickness of 0.6-1.0 cm, cuttings with a length of 13-15 cm, and a single-sided bevel cut, and treated with IBA 800 mg / L solution were the highest, which were 11.44 μmol / m -2 ·s- 1 、11.59μmolm -2 ·s- 1 、11.56μmolm -2 ·s- 1 、11.47μmolm -2 ·s- 1 、11.50μmolm -2 ·s- 1 、11.50μmolm -2 ·s- 1 、12.79μmolm -2 ·s- 1 .

[0079] The intercellular CO2 concentration Ci values ​​of the cuttings seedlings in the group treated with NAA 1000 mg / L solution were the highest, which were 206.23 μmol·mol -1 、220.23μmol·mol -1 、203.76μmol·mol -1 、224.70μmol·mol -1 、219.63μmol·mol -1 、207.13μmol·mol -1 .

[0080] The transpiration rate Tr values ​​of the cuttings seedlings in the groups with cuttings in late December, cutting depth of 10 cm, cutting diameter of 0.6-1.0 cm, cutting length of 13-15 cm, single-side bevel cutting, and IBA 800 mg / L solution treatment were the highest, which were 4.86 mmol·m -2 ·s -1 、4.92mmol·m -2 ·s -1 、5.06mmol·m -2 ·s -1 、4.68mmol·m -2 ·s -1 、4.66mmol·m -2 ·s -1 、4.81mmol·m -2 ·s -1 、4.99mmol·m -2 ·s -1 .

[0081] Among the above photosynthesis results, the net photosynthetic rate Pn value is the most important indicator.

[0082] It can be seen that the suitable time for field cutting seedling cultivation of Castanopsis chinensis in autumn and winter is late October. The upper branches of Castanopsis chinensis are selected as cuttings, with a length of 13-15 cm and a thickness of 0.6-1.0 cm. At the same time, the lower incision is made into a single-sided oblique cut. After being treated with IBA 800 mg / L solution, they are vertically inserted into the seedbed with a cutting depth of 10 cm.

[0083] The present application of the Chinese tallow tree autumn and winter cutting seedling effect can be industrialized production and seedling cost is very low. Compared with grafting seedling, every mu is calculated according to 10,000 seedling amounts, and grafted seedlings need to cultivate stock one year in advance, and every mu of land rent plus seedling fertilizer is not less than 2000 yuan (wherein renting land 300-600 yuan, other seed purchases, processing, shading and management and other costs 1400-1700 yuan), and cutting seedlings do not need to prepare stock in advance, at least every mu saves 2000 yuan. Grafting scion every mu cost is about 1600 yuan (one bud is calculated according to 0.16 yuan), and cutting scion is longer, and every mu is calculated according to 2000 yuan. In terms of labor costs, each person can graft 800 Castanopsis chinensis seedlings per day. Based on a salary of 200 yuan per person, the labor cost for grafting 10,000 trees is 2,500 yuan. For cuttings, each person can graft 7,000 trees per day. Based on a salary of 200 yuan per person, the labor cost for grafting 10,000 trees is 286 yuan. Post-production maintenance costs, including grafting requiring film removal, cost 500 yuan per mu, while cuttings not requiring film removal cost 300 yuan per mu. Therefore, according to the above method, as calculated in Table 5, the cost of cultivating one mu of Castanopsis chinensis seedlings per grafted seedling is 0.66 yuan per plant, while the cost of cuttings per plant can be controlled at 0.26 yuan per plant. The cost per plant of cuttings is 61% lower than that of grafted seedlings, showing excellent prospects for promotion.

[0084] Table 5 Comparison of the cost of cuttings and grafted seedlings of Castanopsis chinensis

[0085]

[0086] In summary, considering the survival rate and later growth conditions, field cutting seedling cultivation of Castanopsis chinensis should be carried out in late October, and the most suitable cutting depth is about 10 cm (2 / 3 of the length of the cutting); the upper branches of the mother plant are the most suitable; the cutting thickness is controlled at 0.6-1.0 cm for the best growth effect; the cutting length is controlled at 13-15 cm, the lower incision shape is a single-sided oblique cut, and the most suitable root-promoting agent is IBA 800 mg / L.

[0087] This application addresses the issues of immature cutting technology for Castanopsis truncatum and the inability to industrialize seedling cultivation. It successfully constructs a technical system for field cuttings of Castanopsis truncatum in autumn and winter, suitable for large-scale production. This provides key technical support for overcoming the seasonal limitations of asexual reproduction of Castanopsis truncatum, enabling year-round seedling cultivation, breeding of improved varieties, and industrial promotion, and is of great significance to the asexual propagation of Castanopsis truncatum seedlings.

[0088] The technical solution of the present invention provides an exemplary description of the invention. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A method for raising seedlings of Castanopsis truncatula by cutting in field in autumn and winter, characterized in that: The following steps are involved: S1. Determine the cutting time: The cutting time is late October or late December; S2. Establishment of seedbed; S3. Cutting selection: Choose strong, semi-lignified branches of the current year, with no disease and full buds; S4. Cutting processing: Cut the cuttings into even stem segments with buds, without retaining leaves in each segment, and make the cuttings smooth; S5. Propagation: Insert the cuttings into the seedbed. After the cuttings are completed, water until the soil is completely penetrated. S6. Management after planting: maintain soil moisture and weed regularly.

2. The method for raising seedlings of Castanopsis truncatula in field during autumn and winter according to claim 1, wherein: The time for cutting is late October or late December.

3. The method for raising seedlings of Castanopsis truncatula in field by cuttings in autumn and winter according to claim 1, wherein: Cutting location: Southern China, further, Hunan Province, further, Changsha-Zhuzhou-Tanzhou area of ​​Hunan Province, most preferably Changsha City.

4. The method for raising seedlings of Castanopsis truncatula in field during autumn and winter according to claim 1, wherein: The seedbed soil in step S2 is at least one of Quaternary red clay and loess.

5. The method for raising seedlings of Castanopsis truncatula in field during autumn and winter according to claim 1, wherein , In step S3, branches in the middle and upper parts of the mother plant are selected as cuttings. In step S4, the thickness of the cuttings does not exceed 1.6 cm, preferably 0.6-1.0 cm; the length of the cuttings is 8-20 cm, preferably 13-15 cm.

6. The method for raising seedlings of Castanopsis truncatula in field during autumn and winter according to claim 1 or 5, characterized in that: In step S4, the upper incision of the cutting is flat, the lower incision is single-sided beveled, the bevel angle of the incision is 40-50 degrees, and the incision is smooth.

7. The method for raising seedlings of Castanopsis truncatula in field by cuttings in autumn and winter according to claim 1, wherein: In step S5, before cutting, the cuttings are dipped in a 750-850 mg / L IBA solution for 3-5 seconds, preferably an 800 mg / L IBA solution, or the cuttings are directly cut without IBA treatment.

8. The method for raising seedlings of Castanopsis truncatula in field during autumn and winter according to claim 1 or 7, characterized in that: The cutting depth in step S5 is 2 / 3-4 / 5 of the cutting, preferably 10 cm.

9. The method for raising seedlings of Castanopsis truncatula in field by cuttings in autumn and winter according to claim 1, 7 or 8, characterized in that: The cutting angle in step S5 is straight cutting, and the cutting spacing is 15cm-20cm.

10. The method for raising seedlings of Castanopsis truncatula by cuttings in field in autumn and winter according to claim 1, characterized in that: In step S6, the soil moisture is maintained at 70%-80%.

Images