Method for producing upper leaves of cv. tsui bei 1

Abstract

The application belongs to the technical field of tobacco, and particularly relates to a production method for improving the quality of upper tobacco leaves of Cuibi No.1, which comprises the following steps: (1) seedling raising, the sowing time being from November 7 to November 15; (2) transplanting, the transplanting time being from January 1 to January 9 of the next year; (3) topping, the topping time being when the tobacco plants bloom and sprout; and (4) harvesting, when 85% to 95% of the leaf surface of the upper tobacco leaves of Cuibi No.1 is yellow-green and more than 3 / 4 of the main veins are white, the upper tobacco leaves of Cuibi No.1 are harvested. Through early sowing, early transplanting, early topping and mature harvesting of Cuibi No.1, and in combination with a specific curing process, the quality of the upper tobacco leaves of Cuibi No.1 and the smoking evaluation score of the cured tobacco are obviously improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tobacco, and particularly relates to a production method of upper leaves of CB-1. BACKGROUND

[0002] CB-1 (Nicotiana tabacum L., CB-1) is a tobacco variety which is recognized by the National Tobacco Variety Approval Committee and is popularized. Due to its special cultivation environment and genetic characteristics, CB-1 has a unique quality style characteristic of clear and sweet tobacco leaves, is one of the characteristic flue-cured tobacco varieties recognized in the industry, and is a typical representative of the clear and sweet style flue-cured tobacco in the Wuyi hilly ecological region belonging to the Fujian tobacco region, and can be used as an ideal raw material for high-grade cigarettes.

[0003] CB-1 has the characteristics of high quality, moderate yield, and clear fragrance, and is favored by domestic cigarette production enterprises. It has entered the formula of key cigarette industrial enterprises and key cigarette brands such as Shanghai Tobacco (Group) Co., Ltd., Jiangsu China Tobacco Industrial Co., Ltd., and Fujian China Tobacco Industrial Co., Ltd. The Wuyi hilly ecological region belonging to the Fujian tobacco region is one of the eight major tobacco flavor style regions in China. The tobacco leaves in the region show a clear and sweet sweet flavor, and the typical characteristics are clear and sweet, obvious sweet flavor, slight floral flavor, and rich flavor types. It plays an irreplaceable role in the formula of industrial enterprises. SUMMARY

[0004] The inventor noticed that the environmental temperature during the field growth period of the Wuyi hilly ecological region presents the characteristics of low in the early stage and high in the later stage. In the early stage, there are more rainy days and insufficient light (the cumulative sunshine duration in the root extension period and the vigorous growth period is only 170.6h), and the synthesis and accumulation of internal substances are less. When the upper leaves mature, it is characterized by high temperature and high humidity (the average temperature is more than 27℃, and the average atmospheric relative humidity is more than 80%), small diurnal temperature difference (about 8℃ on average), which leads to strong respiration intensity of tobacco leaves, more material consumption, and is not conducive to the accumulation of internal substances of tobacco leaves. High temperature and strong light stress during the maturation period can cause the production of strong-flavor tobacco style characteristics. Under the restriction of cultivation measures and ecological factors, the upper leaves of flue-cured tobacco CB-1 are prone to insufficient accumulation of internal substances, uncoordinated chemical composition, and great difference in style characteristics from the middle leaves. The clear and sweet sweet flavor style characteristics are not obvious, the aroma quality is deviated, the scorched flavor is obvious, the dry and burnt odor is heavy, the stimulation is large, and the residue is more.

[0005] Therefore, the inventor improves the cultivation and curing methods according to the characteristics of CB-1 to improve the quality of the upper leaves of CB-1 and the evaluation score of the upper leaves of CB-1.

[0006] The first aspect of the present application provides a production method of upper leaves of Cuibi No. 1, comprising the following steps:

[0007] (1) seedling raising, the sowing time is from November 7th to November 15th;

[0008] (2) transplanting, the transplanting time is from January 1st to January 9th of the next year;

[0009] (3) topping, the topping time is when the tobacco plants bloom and elongate;

[0010] (4) harvesting, when 85% to 95% of the upper leaves of Cuibi No. 1 are yellow-green and the main veins are white for more than 3 / 4, the upper leaves of Cuibi No. 1 are harvested.

[0011] In some embodiments, the sowing time is from November 8th to November 14th. In some embodiments, the sowing time is from November 9th to November 13th. In some embodiments, the sowing time is November 11th. In some embodiments, the sowing time is November 7th, November 8th, November 9th, November 10th, November 11th, November 12th, November 13th, November 14th, November 15th.

[0012] In some embodiments, the transplanting time is from January 1st to January 7th of the next year. In some embodiments, the transplanting time is from January 1st to January 5th of the next year. In some embodiments, the transplanting time is January 5th of the next year. In some embodiments, the transplanting time is January 1st, January 2nd, January 3rd, January 4th, January 5th, January 6th, January 7th, January 8th, January 9th.

[0013] In some embodiments, when 90% of the upper leaves of Cuibi No. 1 are yellow-green and the main veins are white for more than 3 / 4, the upper leaves of Cuibi No. 1 are harvested.

[0014] In some embodiments, the production method comprises one or more of the following:

[0015] 1) seedling raising by sowing Cuibi No. 1 seeds on seedling trays;

[0016] 2) the seedling raising method is wet seedling raising;

[0017] 3) the transplanting site is Fujian tobacco-growing areas;

[0018] 4) the soil texture of the transplanting site is sandy loam;

[0019] 5) the previous crop before transplanting is rice;

[0020] 6) ridging and hole digging on the tobacco field, and transplanting the seedlings after seedling raising into the holes on the field ridges.

[0021] In certain embodiments, the transplanting site is Youxi County, Sanming City, Fujian Province. In certain embodiments, the transplanting site is Longyang Village, Yangzhong Town, Youxi County.

[0022] In certain embodiments, the production method further comprises step (5) curing.

[0023] In certain embodiments, the curing comprises the following steps:

[0024] (a) Early yellowing stage: the upper fresh leaves of Cui Bi No. 1 are placed in a curing barn, and the dry ball temperature of curing is maintained at 36-38°C, and the wet ball temperature is maintained at 35-36°C;

[0025] (b) Middle yellowing stage: the tobacco leaves obtained in step (a) are continuously cured, the dry ball temperature of curing is maintained at 38-40°C, and the wet ball temperature is maintained at 37-38°C;

[0026] (c) Late yellowing stage: the tobacco leaves obtained in step (b) are continuously cured, the dry ball temperature of curing is maintained at 40-42°C, and the wet ball temperature is maintained at about 38°C;

[0027] (d) Early color fixing stage: the tobacco leaves obtained in step (c) are continuously cured, the dry ball temperature of curing is maintained at 43-45°C, and the wet ball temperature is maintained at about 38°C;

[0028] (e) Middle color fixing stage: the tobacco leaves obtained in step (d) are continuously cured, the dry ball temperature of curing is maintained at 46-49°C, and the wet ball temperature is maintained at 38-39°C;

[0029] (f) Late color fixing stage: the tobacco leaves obtained in step (e) are continuously cured, the dry ball temperature of curing is maintained at 50-55°C, and the wet ball temperature is maintained at 39-40°C;

[0030] (g) Dry stem stage: the tobacco leaves obtained in step (f) are continuously cured, the dry ball temperature of curing is maintained at 56-64°C, and the wet ball temperature is maintained at 40-42°C;

[0031] In certain embodiments, the early yellowing stage is dried to 6-8 of the bottom shelf tobacco leaves yellowing. In certain embodiments, the middle yellowing stage is dried to more than 8 of the second layer of tobacco leaves yellowing. In certain embodiments, the late yellowing stage is dried to the second layer of tobacco leaves reaching yellow pieces and green stems. In certain embodiments, the early color fixing stage is dried to more than 8 of the second layer of tobacco leaves reaching yellow pieces and yellow stems. In certain embodiments, the middle color fixing stage is dried to the second layer of tobacco leaves reaching yellow pieces and yellow stems. In certain embodiments, the late color fixing stage is dried to the main veins of the second layer of tobacco leaves turning white and brown. In certain embodiments, the dry stem stage is dried to the dry stems of the tobacco leaves.

[0032] In certain embodiments, the curing comprises one or more of the following:

[0033] 1) in step (a), the baking time is 8-12h;

[0034] 2) in step (b), the baking time is 25-35h;

[0035] 3) in step (c), the baking time is 24-34h;

[0036] 4) in step (d), the baking time is 12-18h;

[0037] 5) in step (e), the baking time is 26-30h;

[0038] 6) in step (f), the baking time is 18-22h;

[0039] 7) in step (g), the baking time is 40-48h.

[0040] In some embodiments, in step (b), the baking time is 30h.

[0041] In some embodiments, in step (c), the baking time is 28-32h.

[0042] The second aspect of the present application provides a tobacco leaf prepared by the production method of the first aspect of the present application.

[0043] The third aspect of the present application provides a tobacco leaf composition comprising the tobacco leaf of the second aspect of the present application.

[0044] The fourth aspect of the present application provides a tobacco product comprising the tobacco leaf of the second aspect of the present application and / or the tobacco leaf composition of the third aspect of the present application. In some embodiments, the tobacco product is a cigarette.

[0045] The fifth aspect of the present application provides the use of the tobacco leaf of the second aspect of the present application and / or the tobacco leaf composition of the third aspect of the present application in a tobacco product. In some embodiments, the tobacco product is a cigarette.

[0046] Terminology

[0047] In the present application, the term “upper tobacco leaf” is determined according to the national standard tobacco terminology (GB / T 18771.1-2015) and generally refers to a number of tobacco leaves growing on the upper part of the main stem of a tobacco plant. It includes upper two-layer leaves and top leaves. Among them, the upper two-layer leaves are a number of upper tobacco leaves growing above the middle leaves and adjacent to the middle leaves; the top leaves are a number of tobacco leaves growing on the uppermost part of the main stem of a tobacco plant.

[0048] In the present application, the term "upper two leaves and boll" generally refers to the several upper leaves growing above and adjacent to the middle leaves, and the term "top leaf" generally refers to the several leaves growing at the uppermost part of the main stem of a tobacco plant. The top leaf and the upper two leaves and boll are collectively referred to as upper leaves.

[0049] In the present application, the term "second leaf from the top" refers to the second leaf from the top of the main stem of a tobacco plant.

[0050] In the present application, the term "fifth leaf from the top" refers to the fifth leaf from the top of the main stem of a tobacco plant.

[0051] In the present application, the term "topping" refers to a farming measure of removing the top of a tobacco plant to reduce the consumption of internal nutrients due to flowering and fruiting, and to promote the distribution of internal nutrients to leaves to improve the quality of tobacco leaves.

[0052] In the present application, the term "midrib" refers to a stem vein in the center of a leaf blade from the petiole to the leaf tip.

[0053] In the present application, the term "presenting a bud" refers to the appearance of a green bud at the top of the main stem of a tobacco plant.

[0054] In the present application, the term "buttoning" refers to the state in which a bud of a tobacco plant is still wrapped in the small leaves at the top.

[0055] In the present application, the term "stem elongation" refers to the phenomenon that the nodes of the main stem of a stem crop grow very quickly at a certain stage of the growth period.

[0056] In the present application, the term "dry-bulb temperature" refers to the value read from a dry-bulb thermometer exposed to air without direct sunlight, which is the actual temperature of the air in contact with the surface of the bulb.

[0057] In the present application, the term "wet-bulb temperature" refers to the temperature shown by a thermometer wrapped with wet gauze, in which the lower end of the gauze is immersed in water to maintain the air humidity at the sensing part to be saturated, and a certain air flow is maintained around the gauze to make the surrounding air approach isotherm. After the reading is stable, the reading shown by the thermometer at this time is approximately considered as the wet-bulb temperature.

[0058] In the present application, the term "ridge" refers to a strip-shaped high ground made in a farmland according to a certain width and interval, which is composed of a ridge platform and a ridge ditch. The ridge platform is located at the upper part of the ridge and is a part of the ridge, and the ridge ditch is a naturally formed ditch between the ridges.

[0059] In the present application, the term "about" means an acceptable level of variation in quantity, level, value, number, frequency, percentage, dimension, size, amount, weight or length in the art. In some embodiments, such variation can be up to 30%, 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1% of the referenced quantity, level, value, number, frequency, percentage, dimension, size, amount, weight or length. When the term "about" is used in conjunction with a numerical range, it modifies that range by extending the boundaries of the range by the acceptable level of variation. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 The figure is a schematic diagram of the growth period meteorological data of flue-cured tobacco and the basic situation of the soil of the test field in the specific embodiment of the present application, wherein TK represents total potassium, TP represents total phosphorus, TN represents total nitrogen, TC represents total carbon, AK represents available potassium, AP represents available phosphorus, AN represents available nitrogen, and SOM represents soil organic matter;

[0061] Figure 2 The figure is a schematic diagram of the influence of different sowing and topping periods on the plant height, stem girth and internode distance of flue-cured tobacco in the specific embodiment of the present application, wherein the numerical value between the two column charts is the P value;

[0062] Figure 3 The figure is a schematic diagram of the influence of different sowing and topping periods on the leaf length, leaf width, leaf thickness and leaf area of the upper leaves of flue-cured tobacco in the specific embodiment of the present application, wherein the numerical value between the two column charts is the P value;

[0063] Figure 4 The figure is a schematic diagram of the influence of different sowing and topping periods on the activity of key enzymes (amylase and sucrose) of carbon metabolism in the specific embodiment of the present application;

[0064] Figure 5 The figure is a schematic diagram of the influence of different sowing and topping periods on the activity of key enzymes (nitrate reductase) of nitrogen metabolism in the specific embodiment of the present application;

[0065] Figure 6 The figure is a schematic diagram of the influence of different sowing and topping periods on the content of key products (reducing sugar, starch and total sugar) of carbon metabolism in the specific embodiment of the present application;

[0066] Figure 7 The figure is a schematic diagram of the influence of different sowing and topping periods on the content of key products (total nitrogen, protein and amino acid) of nitrogen metabolism in the specific embodiment of the present application;

[0067] Figure 8 The figure is a schematic diagram of the influence of different sowing and topping periods on the nicotine content in the specific embodiment of the present application;

[0068] Figure 9 Figure for the influence of different planting and topping time on the content of plastid pigment (chlorophyll a, chlorophyll b, carotenoid) in the specific embodiment of the present application;

[0069] Figure 10 Figure for the influence of different planting and topping time on the content of plastid enzymatic Maillard reactants (polyphenol oxidase, polyphenol) in the specific embodiment of the present application;

[0070] Figure 11 Figure for the correlation between metabolites in upper tobacco leaves at harvest in the specific embodiment of the present application;

[0071] Figure 12 Figure for the correlation coefficient between the regular chemical components and smoking quality of the cured upper tobacco leaves in the specific embodiment of the present application;

[0072] Figure 13 Figure for the content of neutral aroma substances in the cured upper tobacco leaves of different treatments in the specific embodiment of the present application;

[0073] Figure 14 Figure for the content of organic acids in the cured upper tobacco leaves of different treatments in the specific embodiment of the present application;

[0074] Figure 15 Figure for the content of polyphenol in the cured upper tobacco leaves of different treatments in the specific embodiment of the present application.

[0075] Note: Figures 4 to 10 In the specific embodiment, the last point of each fold line is over-mature harvest, and the second last point is mature harvest (C2).

[0076] Beneficial effects

[0077] The production method of the present application promotes the accumulation of starch and the retention of protein, helps to solve the problem of less metabolism and accumulation of internal substances of flue-cured tobacco in Fujian tobacco-growing areas, improves the chemical component composition and sensory quality of flue-cured tobacco, and also helps to form a clean and sweet sweet style. Specific embodiment

[0078] The embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be obtained by purchase.

[0079] Example

[0080] To explore the production method for improving the quality of upper leaves of Cui Bi No. 1, a test was carried out in Longyang Village, Yangzhong Town, Youxi County, Sanming City, Fujian Province from November 2021 to June 2022. The test site is located at North Latitude 26°16'44'' and East Longitude 118°28'20'', with an altitude of 197m. The previous crop in the test field was rice. The soil texture is sandy loam, with medium fertility, uniform texture, flat ground, and convenient irrigation and drainage. There was no soil-borne disease in recent years.

[0081] Before soil preparation and fertilization, mixed soil samples were collected from the plough layer (0-20cm) using the five-point sampling method. After air-drying, the soil nutrients were determined. The basic conditions of the soil in the test field are shown in Table Figure 1 -B. During the test period, the rainfall and temperature during the growth period of flue-cured tobacco in the field were recorded. The meteorological data are shown in Table Figure 1 -A.

[0082] The seedlings were raised by the wet seedling method. When the seedlings grew to five leaves with a central bud, healthy seedlings were selected and transplanted to the field. Each treatment had 1100 tobacco plants, with a row spacing of 110cm and a plant spacing of 50cm. Protective rows were set around.

[0083] Example 1

[0084] Production method for upper leaves of Cui Bi No. 1

[0085] Cui Bi No. 1 seeds were sown on seedling trays for seedling raising. The sowing time was November 11.

[0086] The seedlings after seedling raising were transplanted to the holes in the field ridge. The transplanting time was January 5 of the next year. The transplanting site was Longyang Village, Yangzhong Town, Youxi County, Sanming City, Fujian Province. The soil texture was sandy loam, and the previous crop was rice.

[0087] The fertilization of flue-cured tobacco adopted the fertilization method of base fertilizer and topdressing, dry application and irrigation, and combination of inorganic fertilizer and organic fertilizer. The fertilizer was applied at the right position and at the right time, and was timely and fully absorbed and utilized by the tobacco plants. The fertilizer application method is shown in Table 1.

[0088] When the tobacco plants had buds and stems, the plants were topped.

[0089] When the leaf surface of the upper two layers of tobacco leaves was 85%-95% yellow-green, and the main vein was more than 3 / 4 white, the upper leaves of Cui Bi No. 1 were harvested at one time.

[0090] Table 1

[0091]

[0092] Note: Special-purpose fertilizer is purchased from Fujian Sanming Jinming Agricultural Limited Company, and the execution standard is GB / T15063-2020 production license: (Min) XK13-001-00010 record number: FJFHFL2021-00111. According to the calculation of the applied fertilizer, 6.5 kg of pure nitrogen per mu is applied, and N: P2O5: K2O = 1.0: 0.8: 2.6.

[0093] The harvested tobacco leaves are cured, and the curing conditions are as follows:

[0094] The fresh upper leaves of Cuibi No. 1 are placed in the curing barn, the dry ball temperature in the early yellowing stage is 36-38℃, the wet ball temperature is 35-36℃, and the curing is carried out until the tobacco leaves begin to yellow, the leaf tips are slightly hooked, and the bottom shelf is yellowed for 6-8 times, and the temperature is stabilized for 8-12 h;

[0095] The dry ball temperature in the middle yellowing stage is 38-40℃, the wet ball temperature is 37-38℃, and the curing is carried out until the second layer of tobacco leaves (second layer of tobacco leaves) in the curing barn is yellowed for more than 8 times, and the temperature is stabilized for 30 h;

[0096] The dry ball temperature in the late yellowing stage is 40-42℃, the wet ball temperature is 38℃, and the curing is carried out until the second layer of tobacco leaves reaches yellow piece green vein, the tobacco leaves wither, the branch vein softens, and the temperature is stabilized for 24-32 h;

[0097] The dry ball temperature in the early color fixing stage is 43-45℃, the wet ball temperature is 38℃, and the curing is carried out until the second layer of tobacco leaves reaches yellow piece yellow vein for more than 8 times, the tobacco leaves are hooked and curled, the main vein is softened, the branch vein is yellowed, and the curing is ensured to be soft, and the temperature is stabilized for 12-18 h;

[0098] The dry ball temperature in the middle color fixing stage is 46-49℃, the wet ball temperature is 38-39℃, and the curing is carried out until the second layer of tobacco leaves reaches yellow piece, yellow vein, the leaf tip and leaf edge are hooked and curled, and the temperature is stabilized for 26-30 h;

[0099] The dry ball temperature in the late color fixing stage is 50-55℃, the wet ball temperature is 39-40℃, and the curing is carried out until the main vein of the second layer of tobacco leaves turns white and brown, the leaf is basically dried, and the tobacco leaves reach large curling barrel, and the temperature is stabilized for 18-22 h;

[0100] The dry ball temperature in the dry vein stage is 56-64℃, the wet ball temperature is 40-42℃, and the curing is carried out until the whole tobacco leaves are dry and the temperature is stabilized for 40-48 h.

[0101] Comparative Example 1

[0102] The production method of the upper leaves of Cuibi No. 1 in Reference Example 1 is used, except that the tobacco plants are topped when the tobacco plants present bud and heart; and the upper leaves of Cuibi No. 1 are harvested once when 75% to 80% of the leaf surface of the upper two shelves of tobacco leaves is yellow-green, and the main vein is more than 3 / 5 white. The curing conditions are the same as those of Example 1.

[0103] Comparative Example 2

[0104] The production method of the upper leaves of Cuibiyi No. 1 in Reference Example 1 was used, except that the tobacco plants were topped when 20% of the center flowers of the tobacco plants opened. The curing conditions were the same as in Example 1.

[0105] Comparative Example 3

[0106] The production method of the upper leaves of Cuibiyi No. 1 in Reference Example 1 was used, except that the upper leaves of Cuibiyi No. 1 were harvested in one batch when 75% to 80% of the leaf surface of the upper leaves was yellow-green and the main veins were more than 3 / 5 white. The curing conditions were the same as in Example 1.

[0107] Comparative Example 4

[0108] The production method of the upper leaves of Cuibiyi No. 1 in Reference Example 1 was used, except that the tobacco plants were topped when 20% of the center flowers of the tobacco plants opened and the upper leaves of Cuibiyi No. 1 were harvested in one batch when 75% to 80% of the leaf surface of the upper leaves was yellow-green and the main veins were more than 3 / 5 white. The curing conditions were the same as in Example 1.

[0109] Comparative Example 5

[0110] The production method of the upper leaves of Cuibiyi No. 1 in Reference Example 1 was used, except that the tobacco plants were topped when 20% of the center flowers of the tobacco plants opened. The curing conditions were the same as in Example 1.

[0111] Comparative Example 6

[0112] The production method of the upper leaves of Cuibiyi No. 1 in Reference Example 1 was used, except that the sowing period was November 21 and the transplanting period was January 15 of the following year, the tobacco plants were topped when 20% of the center flowers of the tobacco plants opened, and the upper leaves of Cuibiyi No. 1 were harvested in one batch when 95% or more of the leaf surface of the upper leaves was yellow-green and the main and branch veins were nearly completely white. The curing conditions were the same as in Example 1.

[0113] Comparative Example 7

[0114] The production method of the upper leaves of Cuibiyi No. 1 in Reference Example 1 was used, except that the curing conditions were as follows:

[0115] The dry-bulb temperature during the early yellowing period was 36-38°C and the wet-bulb temperature was 35-36°C, and the temperature was maintained for 8-12 h;

[0116] The dry-bulb temperature during the middle yellowing period was 38-40°C and the wet-bulb temperature was 37-38°C, and the temperature was maintained for 26 h;

[0117] The dry-bulb temperature during the late yellowing period was 40-42°C and the wet-bulb temperature was 38°C, and the temperature was maintained for 28-36 h;

[0118] The dry ball temperature in the early stage of color fixation is 43-45℃, the wet ball temperature is 38℃, and the temperature stabilization time is 12-18h;

[0119] The dry ball temperature in the middle stage of color fixation is 46-49℃, the wet ball temperature is 38-39℃, and the temperature stabilization time is 26-30h;

[0120] The dry ball temperature in the late stage of color fixation is 50-55℃, the wet ball temperature is 39-40℃, and the temperature stabilization time is 18-22h;

[0121] The dry ball temperature in the dry muscle stage is 56-66℃, the wet ball temperature is 40-42℃, and the temperature stabilization time is 28-36h.

[0122] Comparative Example 8

[0123] The production method of the upper tobacco leaves of the Cui Bi No. 1 in the Reference Example 1 is referred to, except that the curing conditions are as follows:

[0124] The dry ball temperature in the early stage of yellowing is 36-38℃, the wet ball temperature is 35-36℃, and the temperature stabilization time is 8-12h;

[0125] The dry ball temperature in the middle stage of yellowing is 38-40℃, the wet ball temperature is 37-38℃, and the temperature stabilization time is 26h;

[0126] The dry ball temperature in the late stage of yellowing is 40-42℃, the wet ball temperature is 38℃, and the temperature stabilization time is 28-36h;

[0127] The dry ball temperature in the early stage of color fixation is 43-45℃, the wet ball temperature is 38℃, and the temperature stabilization time is 12-18h;

[0128] The dry ball temperature in the middle stage of color fixation is 46-49℃, the wet ball temperature is 38-39℃, and the temperature stabilization time is 26-30h;

[0129] The dry ball temperature in the late stage of color fixation is 50-55℃, the wet ball temperature is 39-40℃, and the temperature stabilization time is 18-22h;

[0130] The dry ball temperature in the dry muscle stage is 56-64℃, the wet ball temperature is 40-42℃, and the temperature stabilization time is 40-48h.

[0131] Comparative Example 9

[0132] The production method of the upper tobacco leaves of the Cui Bi No. 1 in the Reference Example 1 is referred to, except that the curing conditions are as follows:

[0133] The dry ball temperature in the early stage of yellowing is 36-38℃, the wet ball temperature is 35-36℃, and the temperature stabilization time is 8-12h;

[0134] The dry bulb temperature during the mid-yellowing stage is 38-40℃, the wet bulb temperature is 37-38℃, and the temperature stabilization time is 20h.

[0135] The dry bulb temperature during the later stage of yellowing is 40-42℃, the wet bulb temperature is 38℃, and the temperature stabilization time is 34-42h.

[0136] The dry-bulb temperature during the initial color-fixing stage is 43-45℃, the wet-bulb temperature is 38℃, and the temperature stabilization time is 12-18h.

[0137] The dry-bulb temperature during the color fixation period is 46-49℃, the wet-bulb temperature is 38-39℃, and the temperature stabilization time is 26-30h.

[0138] The dry-bulb temperature during the later stage of color fixation is 50-55℃, the wet-bulb temperature is 39-40℃, and the temperature stabilization time is 18-22h.

[0139] The dry bulb temperature during the drying period is 56-64℃, the wet bulb temperature is 40-42℃, and the temperature stabilization time is 40-48h.

[0140] Test case

[0141] The different treatments in the production methods of Example 1 and Comparative Examples 1-6 are summarized in Table 2.

[0142] Table 2

[0143]

[0144] In Table 2, the criteria for early harvesting are: 75%–80% of the leaves of the second-stage tobacco plant are yellowish-green, and more than 3 / 5 of the main veins have turned white; the criteria for mature harvesting are: 85%–95% of the leaves of the second-stage tobacco plant are yellowish-green, and more than 3 / 4 of the main veins have turned white; the criteria for over-ripe harvesting are: more than 95% of the leaves of the second-stage tobacco plant are yellowish-green, and the main and branch veins are almost completely white; C1 indicates early harvesting, C2 indicates mature harvesting; D1 indicates topping when buds appear and the heart is closed, D2 indicates topping when buds appear and the joints are formed, and D3 indicates topping when 20% of the central flowers have opened.

[0145] In the above seven treatments, Example 1 and Comparative Examples 1 to 5 were all sown on November 11 and transplanted on January 5. Three topping periods (D1, D2, D3) and three harvest maturity levels (C1, C2, overripe harvest) were set in each treatment. Comparative Example 6 (CK) was sown on November 21 and transplanted on January 15 of the following year. Topping was performed when 20% of the central flowers of the tobacco plant were open, and harvesting was carried out when over 95% of the leaves were yellowish-green and the main and secondary veins were nearly entirely white.

[0146] Experimental Example 1

[0147] Determination of agronomic morphology of flue-cured tobacco under different treatments in Example 1, Comparative Example 2, Comparative Example 5, and Comparative Example 6.

[0148] The harvesting time of Example 1, Comparative Example 2, Comparative Example 5, Comparative Example 6 is all mature harvesting, all C2, while the planting period and the topping period are different, the planting period is early planting, early planting, early planting and late planting respectively, and the topping period is D2, D1, D3 and D3 respectively, to examine the influence of the difference between the planting period and the topping period on the agronomic characters of flue-cured tobacco.

[0149] The main agronomic characters of flue-cured tobacco (including plant height, stem girth, internode distance, leaf length, leaf width, leaf thickness and leaf area) were investigated and determined according to the Tobacco Industry Standard YC / T 142-2010. Ten flue-cured tobacco plants with consistent growth vigor were selected for each treatment at the present budding stage, and the plant height, internode distance and stem girth were measured 7 days before harvesting, and the leaf length, leaf width, leaf thickness of the 2nd and 5th leaves from the top of each plant were measured, and the leaf area was calculated. Leaf area = leaf length x leaf width x leaf area coefficient (0.6345)

[0150] Test results:

[0151] See Figure 2 The plant height, stem girth and internode distance of flue-cured tobacco in different topping period treatments had significant differences (P<0.05) 7 days before harvesting. As can be seen from Figure 2 -A, the plant height of each treatment showed D1<D2<D3<CK, the average plant height of D2 was 87.83 cm, D2 was 97.96% of D3, D1 was 97.72% of D2, and D2 was 86.68% of CK; as can be seen from Figure 2 -B, the stem girth of each treatment showed D1>D2>CK≈D3, the average stem girth of D2 was 11.73 cm, D2 was 1.06 times of D3, and 1.05 times of CK; as can be seen from Figure 2 -C, the internode distance of each treatment showed D1<D2<D3<CK, the average internode distance of D2 was 4.25 cm, D2 was 0.25 cm shorter than D3, and 0.84 cm shorter than CK. When the planting period was the same, with the advance of the topping period, the plant height of the mature flue-cured tobacco gradually decreased, the stem girth gradually increased, and the internode distance gradually decreased; when the topping period was the same, with the delay of the planting period, the plant height and the internode distance increased. Compared with Comparative Example 6 (CK), the plant height, stem girth and internode distance of Example 1 (D2) increased.

[0152] See Figure 3 The leaf length, leaf width, leaf thickness and leaf area of the upper leaves of flue-cured tobacco in different topping period treatments had significant differences (P<0.05). As can be seen from Figure 3 -A, the leaf length of the 2nd leaf from the top of each treatment showed D1<D2<D3<CK, the leaf length of the 2nd leaf from the top of D2 was 53.00 cm, D2 was 92.98% of D3, D1 was 92.45% of D2, and D2 was 89.08% of CK; as can be seen from Figure 3B can be known, the leaf width of the 2nd leaf from the bottom of each treatment is D1 < CK ≈ D2 < D3, the leaf width of the 2nd leaf from the bottom of D2 is 25.17 cm, D2 is 92.07% of D3, and D1 is 93.37% of D2; from Figure 3 C can be known, the leaf thickness of the 2nd leaf from the bottom of each treatment is D1 > D2 > CK ≈ D3, the leaf thickness of the 2nd leaf from the bottom of D2 is 0.33 mm, D2 is 1.08 times of D3, D1 is 1.06 times of D2, and D2 is 1.06 times of CK; from Figure 3 D can be known, the leaf area of the 2nd leaf from the bottom of each treatment is D1 < D2 < CK < D3, the leaf area of the 2nd leaf from the bottom of D2 is 846.63 cm 2 , D2 is 129.65 cm 2 smaller than D3, D1 is 116.10 cm 2 smaller than D2, and D2 is 84.71 cm 2 smaller than CK. From Figure 3 E can be known, the leaf length of the 5th leaf from the bottom of each treatment is D1 < D2 < CK < D3, the leaf length of the 5th leaf from the bottom of D2 is 69.00 cm, D2 is 92.83% of D3, D1 is 92.75% of D2, and D2 is 96.73% of CK; from Figure 3 F can be known, the leaf width of the 5th leaf from the bottom of each treatment is D1 < D2 < CK < D3, the leaf width of the 5th leaf from the bottom of D2 is 31.00 cm, D2 is 93.94% of D3, D1 is 90.87% of D2, and D2 is 95.89% of CK; from Figure 3 G can be known, the leaf thickness of the 5th leaf from the bottom of each treatment is D1 > D2 > D3 ≈ CK, the leaf thickness of the 5th leaf from the bottom of D2 is 0.30 mm, D2 is 1.05 times of CK, and D1 is 1.07 times of D2; from Figure 3 H can be known, the leaf area of the 5th leaf from the bottom of each treatment is D1 < D2 < CK < D3, the leaf area of the 5th leaf from the bottom of D2 is 1350.00 cm 2 , D2 is 206.22 cm 2 smaller than D3, D1 is 192.78 cm 2 smaller than D2, and D2 is 90.16 cm 2 smaller than CK. When the planting time is the same, with the advance of the topping time, the leaf length, the leaf width and the leaf area of the upper leaves of the cured tobacco gradually decrease, the leaf thickness gradually increases, and the leaf width and the leaf area decrease with the delay of the planting time. Compared with the comparative example 6 (CK), the leaf length, the leaf width and the leaf area of the example 1 (D2) slightly increase, and the leaf thickness slightly decreases.

[0153] Test Example 2

[0154] The key enzyme activities of carbon and nitrogen metabolism in upper leaves of flue-cured tobacco under different treatments of Example 1, Comparative Example 2, Comparative Example 5, Comparative Example 6 were determined to investigate the effects of different planting and topping periods on the key enzyme activities of carbon and nitrogen metabolism in upper leaves of flue-cured tobacco.

[0155] Three representative flue-cured tobaccos with uniform growth were selected for each treatment. From the beginning of topping, the 2nd and 5th leaves from the bottom were taken every 7 days, rinsed with clean water, dried, and the main veins at the base of each leaf were removed. The leaves were quickly frozen with a liquid nitrogen tank and stored in a -80℃ refrigerator for determination of the key enzyme activities of carbon and nitrogen metabolism (amylase, sucrose, nitrate reductase) in flue-cured tobacco leaves.

[0156] The activities of amylase and sucrose were determined by 3,5-dinitrosalicylic acid colorimetry, and the activity of nitrate reductase was determined by an in vitro method.

[0157] Test results:

[0158] 1) Effects of different topping periods on the key enzyme activities of carbon metabolism in upper leaves of flue-cured tobacco during the growth and development process

[0159] See Figure 4 , with the maturation of tobacco leaves, the amylase activities in upper leaves of flue-cured tobacco under different planting and topping period treatments all showed an upward trend first and then a downward trend, and the sucrose activities all showed a downward trend first and then a gradual stabilization trend. As can be seen from Figure 4 -A, on the day of topping, the amylase activities in the 2nd leaves from the top of upper leaves of flue-cured tobacco under different treatments were D3 > D2 > CK > D1; 21 days after topping, D3 > CK > D2 > D1; 42 days after topping, again D3 > D2 > CK > D1, CK, D3, D2, and D1 reached the maximum values on the 35th, 42nd, 49th, and 56th days after topping, respectively, at which time, D3 > CK > D2 > D1, and the amylase activities were 2.95 mg / (g·min), 2.38 mg / (g·min), 2.57 mg / (g·min), and 2.24 mg / (g·min), respectively. As can be seen from Figure 4 -C, on the day of topping, the amylase activities in the 5th leaves from the top of upper leaves of flue-cured tobacco under different treatments were CK > D3 > D2 > D1; D1, D2, D3, and CK reached the maximum values on the 56th, 49th, 42nd, and 35th days after topping, respectively, at which time, D3 ≈ CK > D2 > D1, and the amylase activities were 4.54 mg / (g·min), 4.57 mg / (g·min), 4.16 mg / (g·min), and 3.84 mg / (g·min), respectively. As can be seen from Figure 4It can be seen from Table 6 that on the day of topping, the invertase activity of the 2nd leaf from the top of the upper leaves of flue-cured tobacco in different treatments was D1 > D2 > D3 > CK, but there was no significant difference among them; 28 days after topping, the invertase activity of the 2nd leaf from the top of the upper leaves of flue-cured tobacco in different treatments was D1 > CK ≈ D2 > D3; 42 days after topping, there was no significant difference in the invertase activity of the 2nd leaf from the top of the upper leaves of flue-cured tobacco in different treatments. It can be seen from Table 7 that on the day of topping, the invertase activity of the 5th leaf from the top of the upper leaves of flue-cured tobacco in different treatments was CK > D1 > D2 > D3, and there was no significant difference in the invertase activity of the 5th leaf from the top of the upper leaves of flue-cured tobacco in different treatments 28 days after topping. The invertase activity of the upper leaves of flue-cured tobacco gradually decreased with the advance of the topping period at the same time of the same planting period; the invertase activity of the upper leaves of flue-cured tobacco decreased with the delay of the planting period at the same time of the same topping period. The invertase activity of the upper leaves of flue-cured tobacco gradually decreased with the advance of the topping period at the same time of the same planting period; there was no significant difference in the invertase activity of the upper leaves of flue-cured tobacco at the same time of the same topping period. There was no significant difference in the invertase activity of the upper leaves of flue-cured tobacco at the same time of the same planting period. Figure 4

[0160] 2) Effects of different topping periods on the activities of key enzymes in nitrogen metabolism of the upper leaves of flue-cured tobacco during the growth and development process

[0161] See Table 8 Figure 5 The nitrate reductase activity of the upper leaves of flue-cured tobacco in different planting and topping period treatments showed a trend of first decreasing and then stabilizing. On the day of topping, the nitrate reductase activity of the 2nd leaf from the top of the upper leaves of flue-cured tobacco in different treatments was D1 > CK > D2 > D3, and there was no significant difference in the nitrate reductase activity of the 2nd leaf from the top of the upper leaves of flue-cured tobacco 28 days after topping. On the day of topping, the nitrate reductase activity of the 5th leaf from the top of the upper leaves of flue-cured tobacco in different treatments was CK ≈ D1 > D2 > D3, and there was no significant difference in the nitrate reductase activity of the 5th leaf from the top of the upper leaves of flue-cured tobacco 28 days after topping. At the same time, the nitrate reductase activity of the upper leaves of flue-cured tobacco gradually increased with the advance of the topping period at the same time of the same planting period, and there was no significant difference in the nitrate reductase activity of the upper leaves of flue-cured tobacco at the same time of the same topping period. At the same time, the nitrate reductase activity of the upper leaves of flue-cured tobacco gradually increased with the delay of the planting period at the same time of the same topping period, and there was no significant difference in the nitrate reductase activity of the upper leaves of flue-cured tobacco at the same time of the same topping period.

[0162] Test Example 3

[0163] The contents of key products in carbon and nitrogen metabolism of the upper leaves of flue-cured tobacco in different treatments of Example 1, Comparative Example 2, Comparative Example 5, and Comparative Example 6 were determined to examine the effects of differences in planting and topping periods on the key products in carbon and nitrogen metabolism of the upper leaves of flue-cured tobacco.

[0164] ​Each processing selected 3 representative flue-cured tobacco, from the present bud heart starting every 7 days to take the 2 leaves and 5 leaves, after washing with clean water and dry, each remove the main vein of the base of the leaf, quickly in the oven 120℃ fixation 30min, 60℃ drying to constant weight, determination of nicotine, reducing sugar, starch, total sugar, amino acid, protein, total nitrogen content in flue-cured tobacco leaf.

[0165] The nicotine content was determined by extraction and decolorization method, the reducing sugar was determined by 3, 5-dinitrosalicylic acid method, the starch and total sugar content were determined by sulfuric acid anthrone method, the amino acid content was determined by indantrione colorimetry, and the protein and total nitrogen content were determined by Nessler colorimetry.

[0166] Test results:

[0167] See Figure 6 After topping, with the maturity of tobacco leaves, the total sugar, starch and reducing sugar contents of the upper leaves of flue-cured tobacco treated by different planting and topping periods all showed a trend of first increasing and then decreasing. Figure 6 As shown in -A, 6-B, 6-D and 6-E, on the day of topping, the starch and total sugar contents of the upper leaves of flue-cured tobacco were basically the same. Figure 6 As shown in -A, 6-B, 6-D and 6-E, on the 35th day, 42nd day, 49th day and 56th day after topping, the starch and total sugar contents of the 2nd and 5th leaves of the upper leaves of flue-cured tobacco treated by CK, D3, D2 and D1 reached the maximum values, at this time, the starch and total sugar contents of the upper leaves of flue-cured tobacco treated by different planting and topping periods were D1>D2>D3>CK; at the time of mature harvest, the starch and total sugar contents of the upper leaves of flue-cured tobacco treated by different planting and topping periods were still D1>D2>D3>CK. Figure 6 As shown in -C, on the day of topping, the reducing sugar content of the 2nd leaf of the upper leaves of flue-cured tobacco treated by different treatments was D3≈CK>D2>D1; from the 7th day to the 28th day after topping, the reducing sugar content of the 2nd leaf of the upper leaves of flue-cured tobacco treated by different treatments was D3>CK>D2>D1, after the 28th day of topping, the reducing sugar content of the 2nd leaf of the upper leaves of flue-cured tobacco treated by CK began to decrease. On the 28th day, 42nd day, 49th day and 56th day after topping, CK, D3, D2 and D1 reached the maximum values, at this time, the maximum reducing sugar content of the 2nd leaf of the upper leaves of flue-cured tobacco treated by different treatments was D3>D2>CK>D1. Figure 6 As shown in -F, on the day of topping, the reducing sugar content of the upper leaves of flue-cured tobacco treated by different planting and topping periods was D3>CK>D2>D1. On the 35th day, 42nd day, 49th day and 56th day after topping, CK, D3, D2 and D1 reached the maximum values, at this time, the maximum reducing sugar content of the 5th leaf of the upper leaves of flue-cured tobacco treated by different treatments was D3>D2>D1>CK. With the same planting period, at the time of harvest, the starch and total sugar contents gradually increased and the reducing sugar content gradually decreased with the advance of the topping period. With the same topping period, at the time of harvest, the starch, total sugar and reducing sugar contents decreased with the delay of the planting period.

[0168] See Figure 7 With the maturity of tobacco leaves, the total nitrogen, protein and amino acid contents of the upper leaves of flue-cured tobacco treated at different planting and topping periods all showed a trend of first decreasing and then stabilizing. As can be seen from Figure 7 A, 7-D, on the day of topping, the total nitrogen content of the 2nd and 5th leaves of the upper leaves of flue-cured tobacco treated at different periods was D1 > D2 > CK > D3; 49 days after topping, the total nitrogen content of the 5th leaf of the upper leaves of flue-cured tobacco treated at different periods was D2 > D1 > CK > D3. As can be seen from Figure 7 B, on the day of topping, the protein content of the 2nd leaf of the upper leaves of flue-cured tobacco treated at different periods was CK > D1 > D2 > D3, and as can be seen from 7-E, on the day of topping, the protein content of the 5th leaf of the upper leaves of flue-cured tobacco treated at different periods was D1 ≈ CK > D2 > D3; 35 days after topping, the protein content of the 2nd and 5th leaves of the upper leaves of flue-cured tobacco treated at different periods was D1 ≈ D2 > D3 > CK, until harvesting. As can be seen from Figure 7 C, 7-F, on the day of topping, the amino acid content of the upper leaves of flue-cured tobacco treated at different planting and topping periods was CK > D1 > D2 > D3. 14 days after topping, the amino acid content of the upper leaves of flue-cured tobacco treated at different planting and topping periods gradually became smaller and more stable. At the same time, when the planting period was the same, with the advance of the topping period, the total nitrogen and protein content of the upper leaves of flue-cured tobacco gradually increased, and the amino acid content gradually increased in the early stage and showed no significant difference in the later stage; at the same time, when the topping period was the same, with the delay of the planting period, the total nitrogen content increased, the protein content first increased and then decreased, and the amino acid content increased in the early stage and showed no significant difference in the later stage.

[0169] See Figure 8 With the maturity of tobacco leaves, the nicotine content of the upper leaves of flue-cured tobacco treated at different planting and topping periods all showed an upward trend. As can be seen from Figure 8 D, on the 49th, 49th, 56th and 63rd days after topping, the nicotine content of the 2nd and 5th leaves of the upper leaves of flue-cured tobacco treated at D3, CK, D2 and D1 reached the maximum value, at which time D1 > D2 > D3 > CK. At the same time, when the planting period was the same, with the advance of the topping period, the nicotine content of the 2nd leaf of the upper leaves of flue-cured tobacco showed no significant difference, and the nicotine content of the 5th leaf showed no significant difference in the early stage and gradually decreased in the later stage; at the same time, when the topping period was the same, with the delay of the planting period, the nicotine content of the 2nd leaf of the upper leaves of flue-cured tobacco showed no significant difference, and the nicotine content of the 5th leaf showed no significant difference in the early stage and decreased in the later stage.

[0170] Test Example 4

[0171] The chloroplast pigment content of the upper leaves of flue-cured tobacco treated at different periods in Example 1, Comparative Example 2, Comparative Example 5 and Comparative Example 6 was determined to investigate the effect of differences in planting and topping periods on the chloroplast pigment content of the upper leaves of flue-cured tobacco.

[0172] Each processing selects 3 representative flue-cured tobacco, from the present bud heart, every 7 days to take the 2nd leaf and the 5th leaf, after washing with clean water, dry, remove the main vein of each leaf base, quickly freeze with liquid nitrogen tank, store in -80℃ refrigerator, for determination of plastid pigment (chlorophyll a, chlorophyll b, carotenoid) content.

[0173] The spectrophotometric method is used to determine the plastid pigment (chlorophyll a, chlorophyll b, carotenoid) content.

[0174] Test results:

[0175] See Figure 9 , after topping, the chlorophyll a, chlorophyll b and carotenoid content of the upper leaves of flue-cured tobacco treated in different planting periods and topping periods all show a downward trend. From Figure 9 A, 9-B, 9-D, 9-E, 9-F, on the day of topping, the chlorophyll a, chlorophyll b content of the 2nd leaf and the chlorophyll a, chlorophyll b, carotenoid content of the 5th leaf of the upper leaves of flue-cured tobacco treated in different planting periods and topping periods are D1>CK≈D2>D3; from Figure 9 C, on the day of topping, the carotenoid content of the 2nd leaf of the upper leaves of flue-cured tobacco treated in different planting periods and topping periods is D1>D2>D3>CK. By the time of maturity and harvesting, the chlorophyll a content of the 2nd leaf of the upper leaves of flue-cured tobacco treated in different planting periods and topping periods is D3>D2≈D1, the chlorophyll b content is D3>D2≈D1, and the carotenoid content is D1>D2≈D3. By the time of maturity and harvesting, the chlorophyll a, chlorophyll b and carotenoid content of the 5th leaf of the upper leaves of flue-cured tobacco treated in different planting periods and topping periods is D2>D1≈D3. At the same time, when the planting period is the same, with the advance of the topping period, the chlorophyll a, chlorophyll b and carotenoid content of the upper leaves of flue-cured tobacco gradually increases in the early stage, and fluctuates in the later stage. At the same time, when the topping period is the same, for the 2nd leaf, with the delay of the planting period, the chlorophyll a and chlorophyll b content of the upper leaves of flue-cured tobacco increases, and the carotenoid content decreases first and then increases; for the 5th leaf, the chlorophyll a, chlorophyll b and carotenoid content of the upper leaves of flue-cured tobacco gradually increases in the early stage.

[0176] Test Example 5

[0177] The polyphenol content and polyphenol oxidase activity of the upper leaves of flue-cured tobacco under different treatments of Example 1, Comparative Example 2, Comparative Example 5, Comparative Example 6 are determined to examine the influence of the difference between planting and topping period on the polyphenol content and polyphenol oxidase activity of the upper leaves of flue-cured tobacco.

[0178] Each treatment selected 3 representative flue-cured tobacco, after topping every 7 days to take the 2 leaves and 5 leaves, after washing with clean water and dry, each removed from the base of the main vein. A part of the rapid use of liquid nitrogen tank frozen, -80℃ refrigerator for standby, determination of polyphenol oxidase activity in flue-cured tobacco leaves; a part of the oven 120℃ fixation 30min, 60℃ drying to constant weight, determination of polyphenol content in flue-cured tobacco leaves.

[0179] The activity of polyphenol oxidase was determined by catechol colorimetry, and the content of polyphenol was determined by ferrous tartrate colorimetry.

[0180] Test results:

[0181] See Figure 10 , after topping, the activity of polyphenol oxidase and the content of polyphenol in the upper leaves of flue-cured tobacco treated with different planting time and topping time showed a trend of first rising and then falling. From Figure 10It can be seen that on the day of topping, the polyphenol content and polyphenol oxidase activity of the 2nd and 5th leaves of the upper leaves of the tobacco treated by different planting periods and topping periods were D3=CK>D2>D1; until 42 days after topping, the polyphenol content and polyphenol oxidase activity of the 2nd and 5th leaves of the upper leaves of the tobacco treated by D3 and CK reached the maximum; until 49 days after topping, the polyphenol content and polyphenol oxidase activity of the 2nd and 5th leaves of the upper leaves of the tobacco treated by D2 reached the maximum; until 56 days after topping, the polyphenol content and polyphenol oxidase activity of the 2nd and 5th leaves of the upper leaves of the tobacco treated by D1 reached the maximum, at this time, the polyphenol oxidase activity of the 2nd leaves of D1, D2, D3 and CK was 365.00(0.01A / g·min), 434.67(0.01A / g·min), 558.67(0.01A / g·min) and 515.00(0.01A / g·min) respectively, the polyphenol oxidase activity of the 5th leaves of D1, D2, D3 and CK was 311.67(0.01A / g·min), 368.67(0.01A / g·min), 405.33(0.01A / g·min) and 405.33(0.01A / g·min) respectively; the maximum polyphenol content of the 2nd leaves of D1, D2, D3 and CK was 12.22mg / g, 14.91mg / g, 16.53mg / g and 16.53mg / g respectively, the maximum polyphenol content of the 5th leaves of D1, D2, D3 and CK was 12.62mg / g, 13.25mg / g, 15.66mg / g and 15.66mg / g respectively. Until the maturity harvest, the polyphenol content of the 2nd and 5th leaves of the upper leaves of the tobacco treated by different planting periods and topping periods was D3>D2>D1>CK. Until the maturity harvest, the polyphenol oxidase activity of the 2nd and 5th leaves of the upper leaves of the tobacco treated by different planting periods and topping periods was D3>D2>D1, D3>CK. At the same time, when the planting period was the same, with the advance of the topping period, the polyphenol oxidase activity and polyphenol content of the upper leaves of the tobacco gradually decreased. At the same time, when the topping period was the same, with the delay of the planting period, the polyphenol oxidase activity and polyphenol content of the upper leaves of the tobacco almost did not change.

[0182] Test Example 6

[0183] According to the operation of Test Examples 2, 3, 4 and 5, the amylase, invertase, reducing sugar, starch, total sugar, nitrate reductase, nicotine, amino acid, protein, total nitrogen, chlorophyll a, chlorophyll b, carotenoid, polyphenol oxidase and polyphenol of the tobacco obtained by different treatments of Example 1 and Comparative Examples 1-6 were determined.

[0184] Test results:

[0185] Tables 3-1, 3-2 and 3-3 show the activity or content of the metabolites of the upper leaves of the tobacco at the harvest time under different planting and topping periods and different maturity harvests.

[0186] Table 3-1

[0187]

[0188] Table 3-2

[0189]

[0190] Table 3-3

[0191]

[0192] Note: Duncan's test was used, and the data in the table were mean ± standard deviation (n = 3), and different letters indicated significant differences (P < 0.05).

[0193] As shown in Table 3-1, under different topping periods and different harvesting maturities, the amylase activity of the upper leaves at the time of harvesting decreased as the topping time was advanced and as the harvesting time was advanced. The amylase activity of the upper leaves at the time of harvesting of the flue-cured tobacco treated in different topping periods was D1C1 < D2C1 < D3C1, and D1C2 < D2C2 < D3C2. Under different harvesting maturities, the amylase activity of the upper leaves at the time of harvesting was D1C1 < D1C2, D2C1 < D2C2, and D3C1 < D3C2. Under different topping periods and different harvesting maturities, the sucrose activity of the upper leaves at the time of harvesting was not significantly different. Under different topping periods and different harvesting maturities, the reducing sugar content of the upper leaves at the time of harvesting decreased as the topping time was advanced and as the harvesting time was advanced. The reducing sugar content of the upper leaves at the time of harvesting of the flue-cured tobacco treated in different topping periods was D1C1 < D2C1 < D3C1, and D1C2 < D2C2 < D3C2. Under different harvesting maturities, the reducing sugar content of the upper leaves at the time of harvesting was D1C1 < D1C2, D2C1 < D2C2, and D3C1 < D3C2. Under different topping periods and different harvesting maturities, the starch and total sugar content of the upper leaves at the time of harvesting increased as the topping time was advanced and decreased as the harvesting time was advanced. The starch and total sugar content of the upper leaves at the time of harvesting of the flue-cured tobacco treated in different topping periods was D1C1 > D2C1 > D3C1, and D1C2 > D2C2 > D3C2. The starch and total sugar content of the upper leaves at the time of harvesting of the flue-cured tobacco treated in different harvesting maturities was D1C1 < D1C2, D2C1 < D2C2, and D3C1 < D3C2.

[0194] See Table 3-2, under different topping period, different harvest maturity, the upper leaves of the harvest time nitrate reductase activity were no significant difference. Under different topping period, different harvest maturity, the harvest time, the second leaf, nicotine content increased with the topping time forward, the fifth leaf, nicotine content with the topping time forward change rule is not obvious, the second, fifth leaf with the harvest time forward decreased. Different topping period treatment of flue-cured tobacco, the harvest time the second leaf nicotine content of D1C1 > D2C1 > D3C1, D1C2 > D2C2 > D3C2; different harvest maturity, the harvest time the upper leaves of the nicotine content of D1C1 < D1C2, D2C1 < D2C2, D3C1 < D3C2. Different topping period, different harvest maturity, the harvest time the upper leaves of the amino acid content with the topping time forward no significant change, with the harvest time forward increased. Different harvest maturity treatment of flue-cured tobacco upper leaves, the harvest time the amino acid content of D1C1 > D1C2, D2C1 > D2C2, D3C1 > D3C2. Different topping period, different harvest maturity, the harvest time the upper leaves of the protein and total nitrogen content with the topping time and harvest time forward change rule is not obvious.

[0195] See Table 3-3, under different topping period, different harvest maturity, the harvest time the upper leaves of chlorophyll a, chlorophyll b and carotenoid content with the topping time forward fluctuated, with the harvest time forward increased. Different topping period treatment of flue-cured tobacco, the harvest time the second leaf chlorophyll a content of D3C1 > D1C1 ≈ D2C1, D3C2 > D2C2 ≈ D1C2, chlorophyll b content of D1C1 ≈ D2C1 ≈ D3C1, D3C2 > D2C2 ≈ D1C2, carotenoid content of D1C1 > D2C1 ≈ D3C1, D1C2 > D2C2 ≈ D3C2; the harvest time the fifth leaf chlorophyll a, chlorophyll b and carotenoid content of D2C1 > D1C1 ≈ D3C1, D2C2 > D1C2 ≈ D3C2; different harvest maturity, the harvest time the upper leaves of chlorophyll a, chlorophyll b and carotenoid content of D1C1 > D1C2, D2C1 > D2C2, D3C1 > D3C2. Different topping period, different harvest maturity, the harvest time the upper leaves of polyphenol oxidase activity and polyphenol content with the topping time forward decreased, with the harvest time forward decreased. Different topping period treatment of flue-cured tobacco, the harvest time the upper leaves of polyphenol oxidase activity and polyphenol content of D1C1 < D2C1 < D3C1, D1C2 < D2C2 < D3C2; different harvest maturity, the harvest time the upper leaves of nicotine content of D1C1 < D1C2, D2C1 < D2C2, D3C1 < D3C2.

[0196] Figure 11 The correlation between the metabolites of the upper leaves of flue-cured tobacco under different topping period and different harvest maturity is shown.

[0197] Referring to Figure 11 Significant or extremely significant correlations were observed between the metabolites of upper leaves of flue-cured tobacco at different topping times and different harvest maturities. Principal component analysis was used to extract the main components affecting the appearance characteristics of tobacco leaves.

[0198] To study the correlation between the metabolites of upper leaves of flue-cured tobacco, principal component analysis was used to screen the effects of different topping times and different harvest maturities on the quality of upper leaves of flue-cured tobacco. The eigenvalues of principal component analysis are shown in Table 5. The variance contribution rate of the first principal component was 37.418%, that of the second principal component was 27.692%, that of the third principal component was 13.564%, and that of the fourth principal component was 9.579%. The cumulative variance contribution rate of the first four principal components reached 88.253%. Therefore, the four principal components basically represented the characteristics, differences, and mutual relationships of the original variables.

[0199] Table 5

[0200]

[0201] The loading matrix of the four principal components is shown in Table 6. The first principal component was mainly determined by amylase and invertase, and also had a large load of chlorophyll a, chlorophyll b, and amino acid. The second principal component was mainly determined by starch and total sugar, and also had a large load of nicotine. The third principal component was mainly determined by protein and total nitrogen. The fourth principal component was mainly determined by reducing sugar, polyphenol, and polyphenol oxidate. Overall, the first and second principal components had a larger contribution to the quality of fresh tobacco, reaching 65.110%, while the third and fourth principal components had a smaller relative contribution, indicating that the main components of starch, amylase, total sugar, amino acid, invertase, chlorophyll a, chlorophyll b, amino acid, and nicotine had a greater contribution to the aroma substances of tobacco leaves.

[0202] Table 6

[0203]

[0204] The scores of the first four principal components are shown in Table 7. Among the different planting and topping periods and harvesting maturities, the second leaf from the top ranked the highest in the D2C2 principal component comprehensive score, with a principal component score of 1.786; the second leaf from the top ranked the lowest in the D3C1 principal component comprehensive score, with a principal component score of 0.596; the fifth leaf from the top ranked the highest in the D1C1 principal component comprehensive score, with a principal component score of 1.576; and the fifth leaf from the top ranked the lowest in the D1C2 principal component comprehensive score, with a principal component score of 0.047. The variance contribution of the first and second principal components reached 65.110%, dominating the ranking of the principal component comprehensive score. In terms of the analysis, the D1C1 and D2C2 principal component scores ranked higher, which was related to the higher contents of chlorophyll a, chlorophyll b, starch, total sugar, nicotine, protein, total nitrogen and the like in the upper tobacco leaves.

[0205] Table 7

[0206]

[0207]

[0208] Test Example 7

[0209] The chemical components of the cured upper tobacco leaves of Example 1 and Comparative Examples 1-6 were determined.

[0210] The second leaf from the top and the fifth leaf from the top (B2F) of the cured tobacco leaves of Example 1 and Comparative Examples 1-6 were taken to determine the routine chemical components (total sugar, reducing sugar, total nitrogen, total plant alkaloid, potassium and chlorine).

[0211] The FLOWSYS continuous flow analyzer (produced by Systea Company, Italy) was used to determine the chemical components (total sugar, reducing sugar, total nitrogen, total plant alkaloid, potassium and chlorine) in the cured tobacco leaves. The total sugar and reducing sugar were determined by the method of national standard YC / T 159-2019, the starch was determined by the method of national standard YC / T 216-2013, the total nitrogen was determined by the method of national standard YC / T 161-2002, the protein was determined by the method of national standard YC / T 249-2008, the total plant alkaloid was determined by the method of national standard YC / T 160-2002, the potassium was determined by the method of national standard YC / T 217-2007, and the chlorine was determined by the method of national standard YC / T 162-2002.

[0212] Table 8 shows the contents of the routine chemical components of the cured upper tobacco leaves under different topping periods and different harvesting maturities.

[0213] Table 8

[0214]

[0215]

[0216] Note: Duncan's test was used, and the data in the table are mean ± standard deviation (n = 3), with different letters indicating significant differences (P < 0.05).

[0217] As can be seen from Table 8, under different topping periods and different harvesting maturities, the reducing sugar content of the upper tobacco leaves after curing changed irregularly with the advance of the topping time, and increased with the advance of the harvesting time. Under different harvesting maturities, the reducing sugar content of the upper tobacco leaves after curing was D1C1 > D1C2, D2C1 > D2C2, D3C1 > D3C2, and D2C2 > CK. Under different topping periods and different harvesting maturities, the total sugar content of the upper tobacco leaves after curing changed irregularly with the advance of the topping time, and increased with the advance of the harvesting time. The total sugar content of the upper tobacco leaves after curing under different harvesting maturities was D1C1 > D1C2, D2C1 > D2C2, D3C1 > D3C2, and D2C2 > CK.

[0218] As can be seen from Table 8, under different topping periods and different harvesting maturities, the total nitrogen content of the upper tobacco leaves after curing changed irregularly with the advance of the topping time, and basically decreased with the advance of the harvesting time. Under different harvesting maturities, the total nitrogen content of the upper tobacco leaves after curing was D1C1 < D1C2, D2C2 < D2C1 (2 leaves), D2C1 < D2C2 (5 leaves), D3C1 < D3C2, and D2C2 < CK. Under different topping periods and different harvesting maturities, the total plant alkaloid content of the upper tobacco leaves after curing changed irregularly with the advance of the topping time, and decreased with the advance of the harvesting time. Under different harvesting maturities, the total plant alkaloid content of the upper tobacco leaves after curing was D1C1 < D1C2, D2C1 < D2C2, and D3C1 < D3C2; in 2 leaves, CK < D2C2, and in 5 leaves, D2C2 < CK.

[0219] As can be seen from Table 8, under different topping periods and different harvesting maturities, the potassium content of the upper tobacco leaves after curing changed irregularly with the advance of the topping time, and basically increased with the advance of the harvesting time. Under different harvesting maturities, the potassium content of the upper tobacco leaves after curing was D1C1 ≈ D1C2 (2 leaves), D1C1 > D1C2 (5 leaves), D2C1 > D2C2, D3C1 > D3C2, and CK > D2C2. Under different topping periods and different harvesting maturities, the chlorine content of the upper tobacco leaves after curing changed irregularly with the advance of the topping time, and the change rule was also not obvious with the advance of the harvesting time.

[0220] Table 9 shows the chemical component ratio of the upper tobacco leaves after curing under different topping periods and different harvesting maturities.

[0221] Table 9

[0222]

[0223]

[0224] Note: Duncan's test was used, and the data in the table were mean ± standard deviation (n = 3), with different letters indicating significant differences (P < 0.05).

[0225] From Table 9, it can be seen that different topping periods and different harvesting maturities had no obvious effect on the chemical component coordination of the cured upper leaves. Generally, the suitable ranges of the chemical components of high-quality cured tobacco are as follows: two sugar ratio ≥ 0.75, sugar-nitrogen ratio 5-15, sugar-alkali ratio 8-12, nitrogen-alkali ratio 0.8-1.0, and potassium-chlorine ratio > 4. For the two sugar ratio of the second leaf from the top, CK, D1C1, D2C2, and D3C2 were low, and D1C2, D2C1, and D3C1 were in the suitable range. For the two sugar ratio of the fifth leaf from the top, the cured upper leaves were all low. For the sugar-nitrogen ratio of the second leaf from the top, the cured upper leaves were all high. For the sugar-nitrogen ratio of the fifth leaf from the top, the cured upper leaves were all higher than the suitable range, and D1C1, D2C1, and D3C1 were too high. For the sugar-alkali ratio of the second leaf from the top, D1C2 and D3C2 were in the suitable range, D2C2 was high, CK was higher, and D1C1, D2C1, and D3C1 were too high. For the sugar-alkali ratio of the fifth leaf from the top, D1C2 and CK were in the suitable range, D2C2 and D3C2 were high, D1C1 was higher, and D2C1 and D3C1 were too high. For the nitrogen-alkali ratio of the second leaf from the top, D3C1 was in the suitable range, D1C2, D2C2, and D3C2 were low, and D1C1 and D2C1 were high. For the nitrogen-alkali ratio of the fifth leaf from the top, D2C1 was in the suitable range, and the others were low. For the potassium-chlorine ratio of the second leaf from the top, D2C1 was low, D3C2 was lower, and the others were in the suitable range. For the potassium-chlorine ratio of the fifth leaf from the top, the cured upper leaves were all in the suitable range.

[0226] Test Example 8

[0227] Analysis of the sensory evaluation quality of the cured upper leaves of Example 1 and Comparative Examples 1-6.

[0228] The second leaf from the top (B2F) of the cured leaves of Example 1 and Comparative Examples 1-6 was taken for sensory evaluation quality analysis. The samples were evaluated by the Technical Research and Development Center of Fujian Tobacco Industry Co., Ltd. according to the method of YC / T 530-2015.

[0229] Test results:

[0230] Tables 10-A, 10-B, and 10-C show the sensory evaluation quality scores of the cured upper leaves under different topping periods and different harvesting maturities.

[0231] Table 10-A

[0232]

[0233]

[0234] Table 10-B

[0235]

[0236] Table 10-C

[0237]

[0238]

[0239] The results in Tables 10-A, 10-B, and 10-C show that the aroma and sweetness of the cured upper tobacco leaves at different planting and topping times and harvest maturity are all of the "sweet and refreshing" type. Among the style characteristic scores of the cured upper tobacco leaves at different planting and topping times and harvest maturity, D2C1 has the highest score, and D3C2 has the lowest. For the aroma characteristics, D2C2 has the highest score, and D3C2 has the lowest; for the smoke characteristics, D2C2 has the highest score, and D3C2 and CK have the lowest; for the taste characteristics, D2C2 has the highest score, and D3C2 has the lowest. Therefore, the quality characteristic score of the cured upper tobacco leaves is highest for D2C2 and lowest for D3C2. Ultimately, the overall score is highest for D2C2, followed by D2C1, and lowest for D3C2.

[0240] The activity or content of metabolites in the upper leaves of flue-cured tobacco in Tables 3-1, 3-2, and 3-3 of Experimental Example 6 were compared with the smoking scores in Tables 10-A, 10-B, and 10-C of Experimental Example 8. A correlation analysis was performed between groups, and the results are as follows: Figure 12 As shown.

[0241] Depend on Figure 12 The results showed that chlorophyll a was highly significantly correlated with the evaluation score; protein, total nitrogen, amino acids, nitrate reductase, starch, and soluble total sugar were significantly positively correlated with the evaluation score. Reducing sugar was significantly negatively correlated with the evaluation score, while nicotine, sucrase, and amylase were weakly positively correlated with the evaluation score; carotenoids and chlorophyll b were weakly negatively correlated with the evaluation score.

[0242] Experimental Example 9

[0243] The content of neutral aroma compounds in the upper part of the flue-cured tobacco leaves of Example 1 and Comparative Example 6 was determined. The flue-cured tobacco leaves of Example 1 were numbered T, and the flue-cured tobacco leaves of Comparative Example 6 were numbered CK.

[0244] The main pretreatment process for flue-cured tobacco leaves is as follows: Using a distillation extraction method, 20g of crushed and sieved second-to-last tobacco leaf sample is weighed and placed in a 1000mL round-bottom flask. 600mL of distilled water and 2g of citric acid are added. 40mL of dichloromethane is added to a 250mL round-bottom flask, along with 1mL of 0.379mg / mL nitrobenzene as an internal standard. The distillation extraction apparatus is installed simultaneously. The distillation extraction time is until the flask containing the tobacco sample begins to boil, and the organic and aqueous phases separate in the condenser. After distillation for 2.5 hours, 10g of anhydrous sodium sulfate is added to the 250mL flask to absorb any water mixed in with the organic phase. After the solution becomes clear, the organic phase is transferred to a flask and concentrated by rotary evaporation in a 60℃ water bath until the organic phase is concentrated to approximately 1mL, yielding flue-cured tobacco essential oil for later use.

[0245] GC / FID analysis settings: 250℃ injection port temperature, 2μL sample volume, 4:1 split ratio (carrier gas: nitrogen), 1.3mL / min column flow rate; chromatographic column: DB-SMS (size: 30m×0.32mm×0.25μm); temperature program: initial temperature 30℃, hold for 2 min, then increase to 60℃ at a rate of 20℃ / min, then increase to 180℃ at a rate of 2℃ / min, then increase to 280℃ at a rate of 10℃ / min after 2 min, hold for 20 min; detection port temperature 280℃; hydrogen:air:makeup (nitrogen) ratio = 35:40:25 (mL / min); quantification using internal standard method.

[0246] Experimental results:

[0247] To investigate the reasons for the differences in the quality of the upper leaves after curing of flue-cured tobacco of Cuibi No. 1 at different transplanting and topping times and different harvest maturity, the flue-cured tobacco of Experiment Example 6 was used as the control (CK), and the flue-cured tobacco of Experiment Example 1 with the highest evaluation score was used as the treatment (T). The aroma substances of the two bottom leaves with large differences in evaluation were detected.

[0248] Depend on Figure 13 A total of 31 neutral aroma compounds were detected, including 18 carotenoid degradation products, 6 browning reaction products, 5 phenylalanine degradation products, 1 cephalosporin degradation product, and 1 chlorophyll degradation product. Among the carotenoid degradation products, there were significant differences in 6-methyl-5-hepten-2-one and linalool between the control (CK) and test (T), with T showing a higher concentration than CK. Among the browning reaction products, T had significantly higher levels of furfuryl alcohol and 3,4-dimethyl-2,5-furandione than CK. Among the phenylalanine degradation products, T had significantly higher levels of guaiacol than CK. Solanone was detected among the cephalosporin degradation products, with T showing a significantly higher concentration than CK. Neophytadiene, a chlorophyll degradation product, was detected, with T showing a significantly higher concentration than CK. In conclusion, the superior aroma quality of T compared to CK may be related to the significantly higher levels of solanone and neophytadiene in T compared to CK.Figure 13 In this case, the t-test was used, and asterisks indicate significant differences ("*" represents 0.01 < P < 0.05, "**" represents 0.001 < P < 0.01, "***" represents P ≤ 0.001).

[0249] Experimental Example 10

[0250] The organic acid content of the upper tobacco leaves after baking in Example 1 and Comparative Example 6 was measured. The tobacco leaves after baking in Example 1 were numbered T, and the tobacco leaves after baking in Comparative Example 6 were numbered CK.

[0251] The method of YC / T 500-2014 was used to measure the organic acid content.

[0252] Test results:

[0253] From Figure 14 it can be seen that a total of 11 organic acids were detected this time, namely oxalic acid, malonic acid, r-pentanone acid, malic acid, 2,4-heptadienoic acid, citric acid, hexadecanoic acid, heptadecanoic acid, oleic acid, linoleic acid, and octadecanoic acid. Whether it is CK or T, the proportion of organic acids has similarities, and the top three are malic acid, 2,4-heptadienoic acid, and oxalic acid in turn. In the content difference of organic acids, there is no obvious difference between T and CK in terms of malonic acid, r-pentanone acid, malic acid, 2,4-heptadienoic acid, hexadecanoic acid, heptadecanoic acid, oleic acid, linoleic acid, and octadecanoic acid, but the contents of oxalic acid and citric acid in T are significantly lower than those in CK. Figure 14 In this case, the t-test was used, and asterisks indicate significant differences ("*" represents 0.01 < P < 0.05, "**" represents 0.001 < P < 0.01, "***" represents P ≤ 0.001).

[0254] Experimental Example 11

[0255] The polyphenol content of the upper tobacco leaves after baking in Example 1 and Comparative Example 6 was measured. The tobacco leaves after baking in Example 1 were numbered T, and the tobacco leaves after baking in Comparative Example 6 were numbered CK.

[0256] The method of national standard YC / T 202-2006 was used to measure the polyphenol content.

[0257] Test results:

[0258] From Figure 15It can be seen that a total of 5 polyphenols were detected, which were neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, scopoletin and rutin. The polyphenol contents of T and CK showed significant differences. The contents of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid and rutin in T were significantly higher than those in CK, the content of scopoletin in T was significantly lower than that in CK, and the total polyphenol content in T was significantly higher than that in CK. It is speculated that the smoking quality of T is higher than that of CK, which may be related to the fact that the total polyphenol content of T is significantly higher than that of CK. Figure 15 In the above table, t-test was used, and asterisk indicates significant difference ("*" represents 0.01 < P < 0.05, "**" represents 0.001 < P < 0.01, and "***" represents P≤0.001).

[0259] Test Example 12

[0260] Analysis of the smoking quality of the cured upper leaves of Example 1 (numbered T), Comparative Example 7 (numbered C1), Comparative Example 8 (numbered C2), and Comparative Example 9 (numbered C3).

[0261] The cured B2F leaves of Example 1 and Comparative Examples 7-9 were taken for sensory smoking quality analysis.

[0262] The samples were subjected to sensory evaluation according to the method of YC / T 530-2015 by the Technical Research Center of Fujian Tobacco Industry Co., Ltd.

[0263] Test Results

[0264] Table 12 shows the smoking scores of the cured upper leaves under different curing processes.

[0265] Table 12

[0266]

[0267] As shown in Table 12, the aroma and sweetness of the cured upper leaves obtained by different curing processes were all sweet and sweet. The style characteristics of the cured upper leaves were the highest in T, followed by C2, and the lowest in C1. The aroma characteristics score of the cured upper leaves was the highest in C2, followed by T, and the lowest in C1; the smoke characteristics score and the taste characteristics score of the cured upper leaves were relatively high in T and C2, and relatively low in C1; therefore, the quality characteristics score was relatively high in T and C2, and the lowest in C1. Finally, the comprehensive score was relatively high in T and C2, relatively low in C3, and the lowest in C1.

[0268] From the above results, it can be seen that,

[0269] (1) Early topping will hinder the growth of plant height and internode distance, promote the growth of stem circumference, and be beneficial to the cultivation of medium tobacco; early topping breaks the apical dominance of tobacco plants in advance, reduces the nutrient consumption of reproductive growth, prolongs the physiological maturity period of the upper leaves, enhances the carbon metabolism and nitrogen metabolism of the upper leaves, promotes the accumulation of starch and the retention of protein, and helps to solve the problem of less metabolism and accumulation of internal substances of flue-cured tobacco in Fujian tobacco-growing areas.

[0270] (2) Early topping is beneficial to the retention of plastid pigments in the 5th leaf from the bottom, especially chlorophyll a, which may have a certain positive effect on the clear and sweet aroma style and aroma quality of Fujian tobacco; early topping reduces the content of polyphenol oxidase and polyphenols, which may reduce the occurrence of ash deposition during curing and help to improve the appearance quality of cured tobacco leaves such as color.

[0271] (3) Mature harvesting is beneficial to carbon metabolism and can increase starch content, which is beneficial to increasing total sugar content.

[0272] (4) The smoking quality of D2C2 is higher than that of CK, which may be due to the fact that the content of solanone in D2C2 is significantly higher than that of CK, and the content of neophytadiene in D2C2 is significantly higher than that of CK, among which solanone and neophytadiene are compounds recognized in the industry as having a clear aroma type; in polyphenol substances, the contents of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin and total polyphenols in D2C2 are significantly higher than those in CK. Early sowing, early topping and mature harvesting show the characteristics of low fresh tobacco polyphenol content and high cured tobacco leaf content. The increase in the content of solanone helps to stabilize the color of flue-cured tobacco, and the increase in the content of neophytadiene and polyphenols helps to form a clear and sweet style.

[0273] In summary, the present application improves the quality of the upper leaves of Cui Bi No. 1 by early sowing, early transplanting, early topping and mature harvesting, and cooperates with a specific curing process, so that the quality of the upper leaves of Cui Bi No. 1 is significantly improved, and the flue-cured tobacco produced has a very high smoking score.

[0274] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application.

Claims

1. A method for producing upper leaves of Cui Bi No.1, comprising the following steps: (1) seedling raising, the sowing time being from November 7th to November 15th; (2) transplanting, the transplanting time being from January 1st to January 9th of the next year, and the transplanting site being Youxi County, Sanming City, Fujian Province; (3) topping, the topping time being when the tobacco plants are budding and elongating; (4) harvesting, when 85% to 95% of the upper leaves of Cui Bi No.1 are yellow-green, and the main veins are more than 3 / 4 white, the upper leaves of Cui Bi No.1 are harvested; (5) curing, the curing comprising the following steps: (a) early yellowing stage: placing the fresh upper leaves of Cui Bi No.1 into a curing barn, maintaining the dry ball temperature at 36-38℃, maintaining the wet ball temperature at 35-36℃, and curing for 8-12h; (b) middle yellowing stage: continuously curing the leaves obtained in step (a), maintaining the dry ball temperature at 38-40℃, maintaining the wet ball temperature at 37-38℃, and curing for 25-35h; (c) late yellowing stage: continuously curing the leaves obtained in step (b), maintaining the dry ball temperature at 40-42℃, maintaining the wet ball temperature at 38℃, and curing for 24-34h; (d) early color fixing stage: continuously curing the leaves obtained in step (c), maintaining the dry ball temperature at 43-45℃, maintaining the wet ball temperature at 38℃, and curing for 12-18h; (e) middle color fixing stage: continuously curing the leaves obtained in step (d), maintaining the dry ball temperature at 46-49℃, maintaining the wet ball temperature at 38-39℃, and curing for 26-30h; (f) late color fixing stage: continuously curing the leaves obtained in step (e), maintaining the dry ball temperature at 50-55℃, maintaining the wet ball temperature at 39-40℃, and curing for 18-22h; (g) dry stem stage: continuously curing the leaves obtained in step (f), maintaining the dry ball temperature at 56-64℃, maintaining the wet ball temperature at 40-42℃, and curing for 40-48h.

2. The production method according to claim 1, wherein The sowing time is from November 8th to November 14th.

3. The production method of claim 1, wherein, The sowing time is from November 9th to November 13th.

4. The production method of claim 1, wherein, The sowing time is November 11th.

5. The production method of claim 1, wherein, The transplanting time is from January 1st to January 7th of the next year.

6. The production method of claim 1, wherein, The transplanting time is from January 1st to January 5th of the next year.

7. The production method of claim 1, wherein, The transplanting time is January 5th of the next year.

8. The production process according to any one of claims 1 to 7, wherein The upper leaves of Cui Bi No.1 are harvested when 90% of the upper leaves are yellow-green, and the main veins are more than 3 / 4 white.

9. The production process according to any one of claims 1 to 7, wherein The transplanting site is Longyang Village, Yangzhong Town, Youxi County. 10.The method of any one of claims 1-7, comprising one or more of the following: 1) seedling raising by sowing Cui Bi No.1 seeds on seedling trays; 2) the seedling raising mode being wet seedling raising; 3) the transplanting soil texture being sandy loam; 4) the previous crop before transplanting being rice; 5) ridging and hole digging on the tobacco field, and transplanting the seedlings into the holes on the field ridges after seedling raising. 11.The method of any one of claims 1-7, comprising one or two of the following: 1) in step (b), the curing time being 30h; 2) in step (c), the curing time being 28-32h.

12. A tobacco leaf prepared by the method of any one of claims 1-11.

13. A tobacco leaf composition comprising the tobacco leaf of claim 12.

14. A tobacco product comprising the tobacco leaf of claim 12 or the tobacco leaf composition of claim 13.

15. The tobacco article of claim 14, wherein, The tobacco product is a cigarette.

16. Use of the tobacco leaf of claim 12 or the tobacco leaf composition of claim 13 in a tobacco product.

17. The use of claim 16, wherein, The tobacco product is a cigarette.

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