Cultivation and curing process of flue-cured tobacco variety GZ37

Abstract

The application discloses a kind of cultivation and curing process of flue-cured tobacco variety GZ37, comprising: S1 field cultivation;S2 curing process;By improving the traditional low-temperature slow yellowing process, take the curing process of "medium temperature and humidity", increase the curing stage after ignition in yellowing period, control the dry ball temperature 33 DEG C, the wet ball temperature 32 DEG C, preheat for 3h by stable temperature curing, until 80% of tobacco leaf is yellow, yellowing period increases enzyme activity, promotes the transformation of chemical composition to the direction beneficial to quality and color yellowing, effectively reduces the proportion of green smoke, solves the current GZ37 curing existing orange yellow is lighter, more green and brown.

Description

Technical Field

[0001] This invention relates to a cultivation and curing process for the flue-cured tobacco variety GZ37, belonging to the field of tobacco cultivation and curing technology. Background Technology

[0002] Flue-cured tobacco is an important economic crop in my country. Different varieties have different growth characteristics and curing properties, making variety a crucial factor affecting the yield and quality of flue-cured tobacco. However, a flue-cured tobacco variety should also be considered in conjunction with the soil, climate, management techniques, and ecological environment of the actual planting area to highlight its advantages and produce high-quality tobacco leaves with local characteristics. In recent years, some tobacco-growing areas in Shuicheng County, Liupanshui City, Guizhou Province, have experienced a decline in varietal characteristics and economic benefits due to the long-term cultivation of the single variety Yunyan 87. Therefore, it is necessary to actively introduce and screen new varieties (lines) to meet the needs of high-quality and sustainable development of tobacco production. In planting trials, GZ37 has shown high field yield and economic output, while also exhibiting good resistance to adverse conditions and leaf spot diseases. Currently, the agronomic traits of GZ37 obtained through cultivation optimization trials are similar to, or even slightly better than, Yunyan 87. However, its curing quality using the current Yunyan 87 curing process is inferior, exhibiting a paler orange-yellow color and more green veins and brown spots. Further research and improvement are necessary. Summary of the Invention

[0003] Based on the above, the present invention provides a cultivation and curing process for the flue-cured tobacco variety GZ37 to overcome the shortcomings of the prior art.

[0004] The technical solution of this invention is: a cultivation and curing process for the flue-cured tobacco variety GZ37, comprising:

[0005] S1 field cultivation;

[0006] S2 baking process;

[0007] The baking process includes the following steps:

[0008] S21 yellowing stage: After ignition, raise the dry bulb temperature to 33℃ and the wet bulb temperature to 32℃ at a rate of 1℃ / 1h, and bake at a stable temperature for 3h to preheat the tobacco leaves; then raise the dry bulb temperature to 36℃ and the wet bulb temperature to 34℃ at a rate of 1℃ / 1h, and bake at a stable temperature for 5h to 6h until the tips of the tobacco leaves in the high temperature layer turn yellow by 10cm.

[0009] S22: Mid-yellowing stage: Increase the dry bulb temperature to 38℃ and the wet bulb temperature to 36℃ at a rate of 1℃ / 2h, and bake at a stable temperature for 20h to 24h until 80% of the tobacco leaves are 80% yellow; then increase the dry bulb temperature to 40℃ and the wet bulb temperature to 36℃ at a rate of 1℃ / 2h, and bake at a stable temperature for 6h to 8h until the tobacco leaves "collapse" and soften;

[0010] S23: Late yellowing stage: Raise the dry bulb temperature to 42℃ and the wet bulb temperature to 37℃ at a rate of 1℃ / 3h, and bake at a stable temperature for 16h to 20h until the tobacco leaves in the whole kiln reach the state of yellow leaves with green veins and softened main veins.

[0011] S24: Pre-color fixation stage: Increase to 45℃ at 1℃ / 3h, control the wet-bulb temperature at 36℃~38℃, stabilize the temperature for 8h, the auricles turn yellow, the veins turn white, the leaf tips and edges dry, the leaves wilt, and the midrib softens fully; Increase to 48℃ at 1℃ / 3h, control the wet-bulb temperature at 37℃~38℃, stabilize the temperature for 10h, the midrib fades green, and small tubes are formed; Increase to 52℃ at 1℃ / 2h, control the wet-bulb temperature at 38℃, stabilize the temperature for 6h.

[0012] S25: Color fixation stage: Raise the dry bulb temperature to 54℃ at 1℃ / 2h, keep the wet bulb temperature at 37℃~39℃, stabilize the temperature for 18h, the main vein turns yellow, the color difference between the front and back of the tobacco leaf is reduced, the leaves are dry, and the large roll is achieved.

[0013] S26: Drying stage: The dry bulb temperature is increased to 60℃ at a rate of 1℃ / h and kept stable for 6h to 8h, while the wet bulb temperature is between 37℃ and 39℃, and the midrib turns purple and shrinks; the temperature is increased to 68℃ at a rate of 1℃ / h and the wet bulb temperature is between 39℃ and 41℃, and kept stable for 25h to 30h until the tobacco is completely dry.

[0014] Optionally, the field cultivation includes the following steps:

[0015] S11 Ridging and Fertilization;

[0016] S12 transplanting;

[0017] S13 field management;

[0018] S14 top-cutting, leaving leaves.

[0019] Optionally, the base fertilizer applied in the ridge-forming and fertilization step includes organic fertilizer and flue-cured tobacco-specific compound fertilizer, wherein the organic fertilizer is applied at 75 kg / mu and the flue-cured tobacco-specific compound fertilizer is applied at 45 kg / mu, and the N:P2O5:K2O ratio in the flue-cured tobacco-specific compound fertilizer is 10:10:24.

[0020] Optionally, the row spacing is 1.1m and the plant spacing is 0.55m during transplanting, resulting in a transplanting density of 1100 plants per acre. Optionally, the method for topping and retaining leaves is as follows:

[0021] For tobacco plants that are growing normally, top them once after 60% of the central flowers in the field have opened, leaving 18 to 22 leaves;

[0022] For tobacco plants with weak growth, the initial flowering stage should be used, that is, when 40% of the central flowers have opened in the field, the top should be removed, leaving 16 to 18 leaves.

[0023] For tobacco plants with vigorous growth, top-pinching is adopted when 80% of the central flowers in the field have opened, and the top is pinched off once, leaving 19 to 23 leaves.

[0024] The "two-stage topping technique" is implemented. The first topping involves removing the top of the main stem, flower axis, inflorescence, and small leaves together, and removing leaves shorter than 15cm. After the tobacco plant leaves have basically taken shape, the second topping is carried out, removing the top leaves that do not open and have no curing value, and retaining 1-2 nodes of the stem. The main stem is then obliquely cut off at the uppermost node.

[0025] The beneficial effects of this invention are as follows: This invention determines the cultivation method and curing process of the new flue-cured tobacco variety (line) GZ37. The transplanting row spacing for the new variety (line) GZ37 is 110 cm, and the plant spacing is 55 cm. 6.5 kg of pure nitrogen per mu (approximately 0.067 hectares) is applied with medium to high fertility. During the curing process, the temperature and humidity inside the curing barn are controlled, especially improving the traditional low-temperature slow yellowing process by adopting a "medium-temperature, medium-humidity" curing process. For example, after ignition during the yellowing stage, a curing stage is added, controlling the dry bulb temperature at 33℃ and the wet bulb temperature at 32℃, maintaining a stable temperature for 3 hours to preheat the tobacco leaves; during the yellowing stage, the temperature is maintained at 38℃ and the wet bulb temperature at 36℃ for 20-24 hours until 80% of the tobacco leaves are 80% yellow. During the yellowing stage, enzyme activity is increased, promoting the conversion of chemical components to those beneficial to the product. The transformation of tobacco leaves and their yellowing effectively reduces the proportion of green tobacco. During the color-fixing period, the temperature is 48℃, with the wet-bulb temperature between 37℃ and 38℃, maintained for 10 hours. The temperature is then increased to 52℃ at a rate of 1℃ / 2 hours, with the wet-bulb temperature maintained at 38℃ for 6 hours. During the color-fixing period, enzyme activity is gradually reduced and eventually stopped, causing the transformation of starch into sugar and protein into amino acids. This fixes the improved color quality, effectively reducing the color difference between the front and back of the tobacco leaves, lowering the proportion of brown tobacco, and resulting in a more "yellow, bright, and soft" tobacco after curing. During the drying stage, the tobacco stems are dried at a higher temperature and lower relative humidity, with the dry-bulb temperature controlled to not exceed 68℃ and the wet-bulb temperature between 39℃ and 41℃. This prevents the tobacco leaves from turning red due to excessive heat, promotes yellowing, aroma, and softening of the tobacco leaves, and optimizes the yield and quality of the tobacco leaves. Specifically, after adopting this invention, the yield per mu, output value per mu, average price, top-grade tobacco rate, and top-grade tobacco rate of the new variety (line) GZ37 increased by 18.19 kg / mu, 916.33 yuan / mu, 2.12 yuan / kg, 4.38 percentage points, and 5.75 percentage points, respectively. The tobacco leaves have excellent sensory quality and harmonious chemical composition. The new variety (line) GZ37 fully demonstrates the characteristics of the sweet aroma of Shuicheng tobacco leaves, achieving a combination of good varieties and good cultivation methods, thus ensuring planting results. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Example 1:

[0028] The curing process for the flue-cured tobacco variety GZ37 is as follows:

[0029] S1 harvest maturity: Mature;

[0030] S2 yellowing stage: After ignition, raise the dry bulb temperature to 33℃ and the wet bulb temperature to 32℃ at a rate of 1℃ / 1h, and bake at a stable temperature for 3h to preheat the tobacco leaves; then raise the dry bulb temperature to 36℃ and the wet bulb temperature to 34℃ at a rate of 1℃ / 1h, and bake at a stable temperature for 5h to 6h until the tips of the tobacco leaves in the high temperature layer turn yellow by 10cm.

[0031] S3: Mid-yellowing stage: Increase the dry bulb temperature to 38℃ and the wet bulb temperature to 36℃ at a rate of 1℃ / 2h, and bake at a stable temperature for 20h to 24h until 80% of the tobacco leaves are 80% yellow; then increase the dry bulb temperature to 40℃ and the wet bulb temperature to 36℃ at a rate of 1℃ / 2h, and bake at a stable temperature for 6h to 8h until the tobacco leaves "collapse" and soften;

[0032] S4: Late yellowing stage: Increase the dry bulb temperature to 42℃ and the wet bulb temperature to 37℃ at a rate of 1℃ / 3h, and bake at a stable temperature for 16h to 20h until the tobacco leaves in the whole kiln reach the state of yellow leaves with green veins and softened main veins.

[0033] S5: Pre-color fixation stage: Increase to 45℃ at 1℃ / 3h, control the wet-bulb temperature at 36℃~38℃, stabilize the temperature for 8h, the auricles turn yellow, the veins turn white, the leaf tips and edges dry, the leaves wilt, and the midrib softens fully; Increase to 48℃ at 1℃ / 3h, control the wet-bulb temperature at 37℃~38℃, stabilize the temperature for 10h, the midrib fades green, and small tubes are formed; Increase to 52℃ at 1℃ / 2h, control the wet-bulb temperature at 38℃, stabilize the temperature for 6h.

[0034] S6: Color fixation stage: Raise the dry bulb temperature to 54℃ at 1℃ / 2h, keep the wet bulb temperature at 37℃~39℃, stabilize the temperature for 18h, the main vein turns yellow, the color difference between the front and back of the tobacco leaf is reduced, the leaves are dry, and the large roll is achieved.

[0035] S7: Drying stage: The dry bulb temperature is increased to 60℃ at a rate of 1℃ / h and kept stable for 6h to 8h, while the wet bulb temperature is between 37℃ and 39℃, and the midrib turns purple and shrinks; the temperature is increased to 68℃ at a rate of 1℃ / h and the wet bulb temperature is between 39℃ and 41℃, and kept stable for 25h to 30h until the tobacco is completely dry.

[0036] Compare with Example 1:

[0037] The current curing process for the flue-cured tobacco variety GZ37 is as follows:

[0038] S1 harvest maturity: Mature;

[0039] S2 yellowing stage: After ignition, maintain a steady low flame and increase the temperature to 34.0℃~35.0℃ at a rate of 1℃ / h, control the humidity at 33.0℃~35.0℃, and maintain the temperature for 20~25h until the tobacco leaves in the observation layer turn 40%~60% yellow;

[0040] S3 Mid-Yellowing Stage: Increase the temperature to 38.0℃ at a rate of 1℃ / 2h, maintain a humidity of 34.0℃~36.0℃, and bake at a stable temperature for 15~20h until the tobacco leaves in the observation layer turn 70% to 80% yellow; Increase the temperature to 40℃ at a rate of 1℃ / 2h, maintain a humidity of 32.0℃~34.0℃, and bake at a stable temperature for 10~15h until the tobacco leaves in the observation layer turn yellow with green veins;

[0041] S4 yellowing stage: Increase the temperature to 42.0℃ at a rate of 1℃ / 2h~3h, with a humidity of 33.0℃, and bake at a stable temperature for 10~20h until the tobacco leaves in the observation layer are completely yellow and collapse, and 1 / 4~1 / 3 of the main veins of the tobacco leaves turn white and shiny, and then enter the color fixing stage;

[0042] S5: Color Fixing Period: The curing barn temperature starts at 42.0℃ and increases by 3℃ each time, with a heating rate of 1℃ / 2h to 3h, and a stage stabilization time of 6h; among them, when the temperature is between 45.0℃ and 47.0℃, the tobacco leaves are cured at a stable temperature until the main veins turn white and shiny, and the leaf tips are dry; when the temperature is between 53.0℃ and 55.0℃, the leaves are cured at a stable temperature until they are dry; when the color fixing temperature is between 42.1℃ and 48.0℃, the humidity is between 32.0℃ and 34.0℃; when the color fixing temperature is between 48.1℃ and 55.0℃, the humidity is 35℃.

[0043] S6 Drying Period: After the tobacco leaves have reached the color-fixing period requirements, the dry ball temperature is increased from 55.0℃ to 68℃ at a rate of 1℃~2℃ / h. The leaves are then baked at a stable temperature of 60.0℃ for 8 hours, and then baked at a stable temperature of 68℃ until the main veins of all the tobacco leaves in the oven are completely dry. The humidity during the drying period is 38.0℃~40.0℃.

[0044] Compare with Example 2:

[0045] The conventional curing process for the Yunyan 87 flue-cured tobacco variety is as follows:

[0046] S1 harvest maturity: Mature;

[0047] S2 yellowing stage: After ignition, maintain a steady low flame and increase the temperature to 34.0℃~35.0℃ at a rate of 1℃ / h, control the humidity at 33.0℃~35.0℃, and maintain the temperature for 20~25h until the tobacco leaves in the observation layer turn 40%~60% yellow;

[0048] S3 Mid-Yellowing Stage: Increase the temperature to 38.0℃ at a rate of 1℃ / 2h, maintain a humidity of 34.0℃~36.0℃, and bake at a stable temperature for 15~20h until the tobacco leaves in the observation layer turn 70% to 80% yellow; Increase the temperature to 40℃ at a rate of 1℃ / 2h, maintain a humidity of 32.0℃~34.0℃, and bake at a stable temperature for 10~15h until the tobacco leaves in the observation layer turn yellow with green veins;

[0049] S4 yellowing stage: Increase the temperature to 42.0℃ at a rate of 1℃ / 2h~3h, with a humidity of 33.0℃, and bake at a stable temperature for 10~20h until the tobacco leaves in the observation layer are completely yellow and collapse, and 1 / 4~1 / 3 of the main veins of the tobacco leaves turn white and shiny, and then enter the color fixing stage;

[0050] S5: Color Fixing Period: The curing barn temperature starts at 42.0℃ and increases by 3℃ each time, with a heating rate of 1℃ / 2h to 3h, and a stage stabilization time of 6h; among them, when the temperature is between 45.0℃ and 47.0℃, the tobacco leaves are cured at a stable temperature until the main veins turn white and shiny, and the leaf tips are dry; when the temperature is between 53.0℃ and 55.0℃, the leaves are cured at a stable temperature until they are dry; when the color fixing temperature is between 42.1℃ and 48.0℃, the humidity is between 32.0℃ and 34.0℃; when the color fixing temperature is between 48.1℃ and 55.0℃, the humidity is 35℃.

[0051] S6 Drying Period: After the tobacco leaves have reached the color-fixing period requirements, the dry ball temperature is increased from 55.0℃ to 68℃ at a rate of 1℃~2℃ / h. The leaves are then baked at a stable temperature of 60.0℃ for 8 hours, and then baked at a stable temperature of 68℃ until the main veins of all the tobacco leaves in the oven are completely dry. The humidity during the drying period is 38.0℃~40.0℃.

[0052] The middle leaves of flue-cured tobacco varieties GZ37 and Yunyan 87 were used as experimental materials. They were cured according to the curing methods in Example 1, Control Example 1, and 2, respectively. Except for the differences in curing process and tobacco varieties themselves, all other aspects were the same. It should be noted that tobacco leaves with relatively uniform growth that were planted at the same time in the same plot were selected as the cured tobacco leaves.

[0053] The following section explains the impact on the sensory quality, overall quality, and chemical composition of the upper tobacco leaves after curing.

[0054] 1. Sensory evaluation of tobacco leaf smoking quality

[0055] Table 1 Comparison of sensory evaluations of tobacco leaves

[0056]

[0057] As shown in Table 1, the flue-cured tobacco variety GZ37 can better highlight the sweet and fragrant style of the planting area. Before the improvement of the curing process, the overall quality evaluation of the flue-cured tobacco variety GZ37 was slightly worse than that of Yunyan 87. After the improvement of the curing process, the aroma of the flue-cured tobacco variety GZ37 is fuller than that of Yunyan 87, and the smoke is less irritating. The overall sensory quality of the pilot test is comparable to that of Yunyan 87.

[0058] 2. Quality of tobacco leaves after curing

[0059] Table 2 Comparison of the quality of flue-cured tobacco leaves

[0060] Variety name Green leaf / % Mixed colour leaf / % Stiff leaf / % Yellowish soft leaf / % GZ37 (Example 1) 1.23 1.34 0.25 97.18 GZ37 (Comparative Example 1) 1.48 2.86 0.42 95.24 Yunyan 87 (Comparative Example 2) 1.24 2.42 0.41 95.93

[0061] As shown in Table 2, after the improvement of the curing process, the proportion of green, impure, and stunted tobacco leaves decreased by 1.94 percentage points, while the proportion of bright yellow and soft tobacco leaves increased. The cured tobacco leaves are clean, loosely structured, have high oil content and strong color, and the number of green, impure, and stunted tobacco leaves is reduced, thus reducing curing losses and improving the quality of the cured tobacco leaves. The quality of the tobacco leaves is more in line with the requirements of "yellow, bright, and soft".

[0062] 3. Chemical composition of flue-cured tobacco leaves

[0063] Table 3 Comparison of chemical components in cured tobacco leaves

[0064]

[0065]

[0066] As shown in Table 3, after the improvement of the curing process, the total sugar and reducing sugar content of the flue-cured tobacco variety GZ37 increased by 0.53% and 0.7% respectively, the nicotine content decreased slightly, the chlorine and potassium content remained relatively stable, the sugar-to-nicotine ratio was appropriate, and the overall chemical composition of the tobacco leaves was coordinated.

[0067] Example 2:

[0068] The cultivation techniques for the flue-cured tobacco variety GZ37 are as follows:

[0069] Step 1: Ridge making and fertilization;

[0070] S1. From March 20th to April 10th, ridges should be erected with a row spacing of 110cm, a ridge height of 25cm, a top width of 25cm, and a bottom width of 70cm-80cm. The ridges should be full, with straight furrows and fine soil. The ridge spacing and height should be consistent within the same plot or area. The ridges should ideally run north-south. On gentle slopes, ridges should be erected along contour lines, and the ridge direction should be consistent within the same contiguous area.

[0071] S2. Based on the shape of the plot, draw ropes to open the ridges and apply base fertilizer in strips. The base fertilizer mainly uses commercial organic fertilizer and flue-cured tobacco-specific compound fertilizer (N:P2O5:K2O ratio of 10:10:24), of which 75 kg / mu of commercial organic fertilizer and 45 kg / mu of flue-cured tobacco-specific compound fertilizer are used.

[0072] S3. After ridging the tobacco field, cover it with film immediately or wait until the soil moisture of the ridge is greater than 70%. Pull the rope to break the film and make water replenishment holes according to the transplanting spacing. The diameter of the film hole should be 15 cm. After making the hole, cover the film hole with fine soil to make the film hole concave.

[0073] Step Two: Transplanting;

[0074] S1, transplanting from April 25th to April 30th.

[0075] S2. Within the same area, the transplanting period should be controlled within 5 days, and the transplanting period for each tobacco farmer should be controlled within 3 days.

[0076] S3. Use a hole punch to make holes, controlling the hole depth so that the functional leaves are exposed after transplanting. When transplanting, place the tobacco seedling into the hole, fill the gap with soil, and gently press to ensure that the seedling substrate is in full contact with the soil. On the same day after transplanting, apply 2.5 kg / mu of special seedling fertilizer (N:P2O5:K2O ratio of 22:14:10) diluted with water.

[0077] S4: Row spacing 1.1m, plant spacing 0.55m, transplanting density is 1100 plants per mu.

[0078] Step 3: Field Management;

[0079] S1. Topdressing: Apply 15 kg / mu of topdressing fertilizer (N:P2O5:K2O ratio of 15:0:30) within 20 days after transplanting the tobacco plants. When the soil moisture is sufficient, you can also apply topdressing fertilizer by drilling 3 to 5 holes at the vertical position of the longest leaf tip around the tobacco plant.

[0080] S2. Uncovering the film (breaking the film): 30 to 40 days after transplanting, uncover or break the film (the diameter of the broken film is 15 cm) according to the growth of the tobacco plants. Weeding and building the ridges should be carried out at the same time. The ridges should be 30 cm high. Ensure that there are no weeds in the field. Remove the bottom leaves in time and dispose of them in the field. One week before harvesting and curing, remove the bottom 5 to 6 unsuitable fresh tobacco leaves.

[0081] Step 4: Remove the top leaves;

[0082] For tobacco plants that are growing normally, top them once after 60% of the central flowers in the field have opened, leaving 18 to 22 leaves;

[0083] For tobacco plants with weak growth, the initial flowering stage should be used, that is, when 40% of the central flowers have opened in the field, the top should be removed, leaving 16 to 18 leaves.

[0084] For tobacco plants with vigorous growth, top-pinching is adopted when 80% of the central flowers in the field have opened, and the top is pinched off once, leaving 19 to 23 leaves.

[0085] The "two-stage topping technique" is implemented. The first topping involves removing the top of the main stem, flower axis, inflorescence, and small leaves together, and removing leaves shorter than 15cm. After the tobacco plant leaves have basically taken shape, the second topping is carried out, removing the top leaves that do not open and have no curing value, and retaining 1-2 nodes of the stem. The main stem is then obliquely cut off at the uppermost node.

[0086] Comparative Example 3: Cultivation Techniques of Flue-cured Tobacco Variety GZ37

[0087] When ridging and fertilizing, apply 50 kg / mu of compound fertilizer specifically for flue-cured tobacco.

[0088] When transplanting, the spacing between plants should be 50cm, and the transplanting density should be 1200 plants per acre;

[0089] Topping and leaving leaves should be done as follows:

[0090] For tobacco plants that are growing normally, top them once after 50% of the central flowers in the field have opened, leaving 18 to 20 leaves;

[0091] For tobacco plants with weak growth, the initial flowering stage should be used, that is, when about 15% of the central flowers have opened in the field, the top should be removed, leaving 16 to 18 leaves.

[0092] For tobacco plants with vigorous growth, top-pinching is adopted when 60% of the central flowers in the field have opened, and the top is pinched off all at once, leaving 19 to 23 leaves.

[0093] The rest is the same as in Example 1.

[0094] Comparative Example 4: Cultivation Techniques of Flue-cured Tobacco Variety Yunyan 87

[0095] The cultivation process of Yunyan 87 is the same as that of control example 2.

[0096] A comparative study was conducted within the same field area, without duplication. The main locally grown variety, Yunyan 87, and its cultivation techniques, along with the flue-cured tobacco variety GZ37 cultivated using the Yunyan 87 cultivation techniques, served as controls. Pest and disease control was carried out according to the most suitable methods for local production, with particular attention to the prevention and control of bacterial wilt. Other management measures were implemented according to the local high-quality tobacco cultivation technical regulations, and each field management technique and measurement was completed on the same day.

[0097] Results analysis:

[0098] 1. Field growth period record

[0099] Table 4. Field growth period records

[0100]

[0101] As shown in Table 4, after the improvement of cultivation techniques, the field growth period of flue-cured tobacco variety GZ37 was shortened by 6 days, which is comparable to the field growth period of the local main variety Yunyan 87.

[0102] 2. Record of agronomic traits

[0103] Table 5. Survey of agronomic traits during topping period

[0104]

[0105] Table 5 shows that after the improvement of cultivation techniques, the natural plant height, natural number of leaves, topped plant height, number of harvestable leaves, maximum leaf length and width, and the length and width of the top three leaves (from top to bottom) of the flue-cured tobacco variety GZ37 were 18.84 cm higher, 3 more leaves, 10.19 cm higher, 3 more leaves, 2.3 cm longer, 6.65 cm wider, 6.36 cm longer, and 5.12 cm wider than those of Yunyan 87; and compared to GZ37 (control example 3), the natural plant height, natural number of leaves, topped plant height, topped plant height, topped plant height, topped plant height, topped plant height, topped plant height, topped plant length ...

[0106] 3. Natural disease occurrence in the field

[0107] Table 6. Disease incidence survey

[0108]

[0109] As shown in Table 6, after the improvement of cultivation techniques, the incidence of climate spot disease and tobacco virus disease in GZ37 was 6.35 and 4.5 percentage points lower than that in Yunyan 87, respectively. In particular, the incidence of powdery mildew decreased significantly, and there was zero occurrence of root and stem diseases in GZ37. This indicates that with the improvement of cultivation techniques, GZ37 has stronger disease resistance than Yunyan 87 and effectively reduces disease losses.

[0110] 4. Main economic characteristics

[0111] Table 7. Survey Form on Major Economic Characteristics

[0112]

[0113] As shown in Table 7, after the cultivation techniques were improved, the yield, output value, average price, percentage of top-grade tobacco, and percentage of top-grade tobacco in the middle section of GZ37 were 18.07 kg / mu, 917.84 yuan / mu, 2.12 yuan / kg, 4.16 percentage points, and 0.78 percentage points higher than those of Yunyan 87, respectively. Compared with GZ37 before the improvement, the yield, output value, average price, percentage of top-grade tobacco, and percentage of top-grade tobacco in the middle section of GZ37 were 6.87 kg / mu, 550.8 yuan / mu, 2.2 yuan / kg, 2.32 percentage points, and 2.02 percentage points higher than those of Yunyan 87, respectively. This indicates that the improved cultivation techniques of GZ37 effectively improved the yield and quality of flue-cured tobacco, significantly increasing farmers' income.

[0114] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A cultivation and curing process for a flue-cured tobacco variety GZ37, characterized in that, include: S1 field cultivation; S2 baking process; The field cultivation includes the following steps: S11 Ridging and Fertilization; S12 transplanting; S13 field management; S14 Topping and Leaf Retention: The topping and leaf retention method is as follows: For normally growing tobacco plants, top them once after 60% of the central flowers in the field have opened, leaving 18 to 22 leaves; for weaker tobacco plants, top them at the initial flowering stage, that is, when 40% of the central flowers in the field have opened, leaving 16 to 18 leaves; for vigorous tobacco plants, top them at the peak flowering stage, that is, when 80% of the central flowers in the field have opened, top them once, leaving 19 to 23 leaves; implement "two-stage topping technique", the first topping removes the top of the main stem, flower axis, inflorescence, and small leaves together, and removes leaves less than 15cm long. After the tobacco plant leaves are basically shaped, perform a second topping, remove the top leaves that do not open and have no curing value, and retain 1 to 2 nodes of the stem; cut the main stem obliquely at the uppermost node; The baking process includes the following steps: S21 yellowing stage: After ignition, raise the dry bulb temperature to 33℃ and the wet bulb temperature to 32℃ at a rate of 1℃ / 1h, and bake at a stable temperature for 3h to preheat the tobacco leaves; then raise the dry bulb temperature to 36℃ and the wet bulb temperature to 34℃ at a rate of 1℃ / 1h, and bake at a stable temperature for 5h to 6h until the tips of the tobacco leaves in the high temperature layer turn yellow by 10cm. S22: Mid-yellowing stage: Increase the dry bulb temperature to 38℃ and the wet bulb temperature to 36℃ at a rate of 1℃ / 2h, and bake at a stable temperature for 20h to 24h until 80% of the tobacco leaves are 80% yellow; then increase the dry bulb temperature to 40℃ and the wet bulb temperature to 36℃ at a rate of 1℃ / 2h, and bake at a stable temperature for 6h to 8h until the tobacco leaves "collapse" and soften. S23: Late yellowing stage: Raise the dry bulb temperature to 42℃ and the wet bulb temperature to 37℃ at a rate of 1℃ / 3h, and bake at a stable temperature for 16h to 20h until the tobacco leaves in the whole kiln reach the state of yellow leaves with green veins and softened main veins. S24: Pre-color fixation stage: Increase temperature to 45℃ at 1℃ / 3 h, control wet-bulb temperature at 36℃~38℃, stabilize temperature for 8 h, auricles turn yellow, veins turn white, leaf tips and edges dry, leaves wilt, and midribs soften fully; Increase temperature to 48℃ at 1℃ / 3 h, control wet-bulb temperature at 37℃~38℃, stabilize temperature for 10 h, midribs fade green, small tubes form; Increase temperature to 52℃ at 1℃ / 2 h, control wet-bulb temperature at 38℃, stabilize temperature for 6 h; S25: Color fixation stage: Raise the dry bulb temperature to 54℃ at 1℃ / 2h, keep the wet bulb temperature at 37℃~39℃, stabilize the temperature for 18h, the main vein turns yellow, the color difference between the front and back of the tobacco leaf is reduced, the leaves are dry, and the large roll is achieved. S26: Drying stage: The dry bulb temperature is increased to 60℃ at a rate of 1℃ / h and kept stable for 6h to 8h, while the wet bulb temperature is between 37℃ and 39℃, and the midrib turns purple and shrinks; the temperature is increased to 68℃ at a rate of 1℃ / h and the wet bulb temperature is between 39℃ and 41℃, and kept stable for 25h to 30h until the tobacco is completely dry.

2. The cultivation and curing process of the flue-cured tobacco variety GZ37 according to claim 1, characterized in that, The base fertilizer applied in the ridge-forming and fertilization step includes organic fertilizer and flue-cured tobacco-specific compound fertilizer. The organic fertilizer is applied at 75 kg / mu, and the flue-cured tobacco-specific compound fertilizer is applied at 45 kg / mu. The N:P2O5:K2O ratio in the flue-cured tobacco-specific compound fertilizer is 10:10:

24.

3. The cultivation and curing process of the flue-cured tobacco variety GZ37 according to claim 1, characterized in that, The row spacing is 1.1m and the plant spacing is 0.55m, with a transplanting density of 1100 plants per mu.

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