A method for identifying overall maturity of cigar tobacco germplasm resources

Abstract

The application provides a method for identifying overall maturity of cigar tobacco germplasm resources, and belongs to the technical field of cigar tobacco germplasm resource identification and tobacco leaf harvesting. The identification method comprises the following steps: measuring chlorophyll content of upper, middle and lower leaves (or upper and middle leaves) of cigar tobacco at the mature period of the cigar tobacco; calculating average values and variation coefficients of the chlorophyll content of the upper, middle and lower leaves (or the upper and middle leaves) of the variety; when the average variation coefficient of the whole plant is less than 15% (or less than 11.7%), the variety is identified as a whole plant maturity consistent variety, and whole plant or half whole plant harvesting can be carried out. The identification method is conducive to screening cigar tobacco varieties suitable for whole plant / half whole plant harvesting, and contributes to shortening the harvesting period, reducing the harvesting cost, and improving the appearance quality and sensory quality of cigar tobacco leaves.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cigar tobacco germplasm resource identification and tobacco leaf harvesting, and particularly relates to a method for identifying overall maturity of cigar tobacco germplasm resources. BACKGROUND

[0002] In recent years, the Chinese cigar market has experienced explosive growth. Domestic handmade cigars have grown from 2 million in 2017 to over 20 million in 2021, with an average annual growth rate of over 70%. China is the fastest-growing market for cigar consumption globally. Cigar tobacco has become a new economic growth point for the tobacco industry. With the development of modern agricultural technology, Chinese tobacco production has basically achieved mechanization or partial mechanization in seedling, planting, fertilization, weeding, and topping. Due to the complexity of cigar tobacco harvesting and the high requirements of post-fermentation on harvesting quality, unlike the harvesting of other crops, cigar tobacco harvesting in China is basically completed by manual labor. Harvesting is a labor-intensive industry that requires a large amount of labor, and harvesting operations have become a bottleneck in the full mechanization of tobacco production. Therefore, cultivating cigar tobacco varieties suitable for mechanization and whole-plant harvesting is of great significance for reducing labor and cost and promoting the sustainable development of the cigar tobacco industry.

[0003] Maturity is the first element of tobacco leaf appearance quality and the central factor in quality formation. Cigar tobacco leaves with good harvesting maturity are easy to cure, and the cured leaves have good quality, high grade, and good flavor. Factors affecting tobacco leaf maturity include internal factors and external factors. Internal factors include genetic factors and leaf attachment sites, while external factors include climate factors, soil conditions, cultivation conditions, mature harvesting, and scientific curing. Tobacco leaf maturity refers to a certain period of tobacco leaf growth and development. Harvesting and conditioning at this stage can best meet the needs of the cigarette industry for raw tobacco, and the leaves have certain characteristics, including leaf tissue structure, chemical composition, physiological function, biochemical reaction, and external morphological characteristics. Moreover, the judgment of maturity varies with individuals, time, leaf attachment sites, and environmental conditions.

[0004] At present, the maturity of tobacco leaves is determined by sensory perception such as visual observation and touch. The qualitative standards mainly include leaf color, changes in main veins, hair shedding, and cross-section at the time of harvesting. When the tobacco leaves mature, the leaf color turns yellow, which is characterized by the gradual disappearance of green color and the appearance of yellow-green color in different degrees. With the improvement of the maturity of tobacco leaves, the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids decrease, but the proportion of carotenoids in the total amount of pigments increases. The appearance of these changes in pigments reflects the changes in color during the maturation of tobacco leaves, indicating that the yellowing of leaf color is one of the characteristics of tobacco leaf maturity. The harvesting standards for tobacco leaves are as follows: the lower leaves are yellow-green, about 6-7 / 10 yellow, and the main veins are more than 1 / 2 white; the middle leaves are light yellow, about 8-9 / 10 yellow, and the main veins are more than 2 / 3 white; and the upper leaves are basically all yellow, about 9-10 / 10 yellow. According to the categories, cigar tobacco leaves can be divided into jacket and core. The harvesting standards for the core are similar to those for flue-cured tobacco, while the harvesting maturity of the jacket is lower than that of flue-cured tobacco. The jacket tobacco leaves are harvested according to the maturity standards and positions from bottom to top about 80-90 days after transplanting, 3-4 leaves at a time, every 7 days, and 5-6 times per plant.

[0005] In addition to color, the indicators for qualitatively grasping maturity also include hair and sound. During the maturation process of tobacco leaves, the density of villi and glandular hairs changes significantly with the development of the leaves. When the leaves approach the process maturity, the secretion of glandular hairs increases, and the elasticity of the leaves increases. When the leaves enter the process maturity, the secretion of glandular hairs overflows, the leaves have the maximum stickiness and good elasticity. When the leaves enter the over-maturity, the glandular heads fall off, the secretion activity decreases, the elasticity of the leaves decreases, and the internal quality decreases. Studies have shown that when the lower leaves mature, the villi hardly fall off; when the middle leaves mature, the villi partially fall off; and when the upper leaves mature, the villi mostly fall off. When the tobacco leaves are harvested, a separation layer is produced at the base of the leaves, making them easy to pick. The sound is clear and crisp, the cross-section is neat, and the stem is not included, showing a horseshoe shape.

[0006] The quantitative standards for the maturity of tobacco leaves mainly include leaf age and stem-leaf angle. Studies by Jin Wenhua et al. have shown that the optimal harvesting time for lower leaves is 9 weeks, for middle leaves is 11 weeks, and for upper leaves is 10-12 weeks. Studies by Wang Huai-zhu et al. have shown that the stem-leaf angle can reflect the maturity of tobacco leaves during the maturation process. Studies by Xia Kai et al. have shown that the leaf thickness, palisade tissue thickness, and the number of palisade tissue cells per unit length of different varieties of tobacco leaves decrease with the improvement of the maturity of tobacco leaves. The thickness of fresh leaves on tobacco plants in the field is used as an indicator of the maturity of tobacco leaves.

[0007] The above-mentioned method for identifying the maturity of tobacco leaves is only applicable to single leaves, and no one has ever studied a method for identifying the maturity of whole plants. Moreover, some identification methods require laboratory conditions and are too time-consuming and laborious. The demand for varieties suitable for whole-plant harvesting is particularly urgent in production, as it can significantly reduce production costs and improve the appearance and sensory quality of cigar tobacco leaves. Therefore, establishing a method for identifying the overall maturity of cigar tobacco germplasm resources will help screen cigar tobacco varieties suitable for whole-plant / half-plant harvesting, thereby reducing the harvesting period and cost and improving the appearance and sensory quality of cigar tobacco leaves. SUMMARY

[0008] Therefore, the purpose of the present application is to provide a method for identifying the overall maturity of cigar tobacco germplasm resources and to establish cigar tobacco germplasm resources suitable for whole-plant / half-plant harvesting, thereby providing a reference for the harvesting method and germplasm for cigar tobacco production in production areas.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0010] A method for identifying the overall maturity of cigar tobacco germplasm resources, characterized in that it comprises the following steps: measuring the chlorophyll content of the upper, middle, and lower leaves of cigar tobacco at the maturity stage; calculating the average value and coefficient of variation of the chlorophyll content of the upper, middle, and lower leaves of the variety; and identifying the variety as having consistent overall maturity and being suitable for whole-plant or half-plant harvesting when the average coefficient of variation of the whole plant is less than 15%.

[0011] Or, at the maturity stage of cigar tobacco, the chlorophyll content of the upper and middle leaves of cigar tobacco is measured; the average value and coefficient of variation of the chlorophyll content of the upper and middle leaves of the variety are calculated; and the variety is identified as having consistent overall maturity and being suitable for half-plant harvesting when the average coefficient of variation of the whole plant is less than 11.7%.

[0012] Preferably, the cigar tobacco is a variety with an average leaf number of ≥17.

[0013] More preferably, the leaf number is counted at the initial flowering stage of the tobacco plant.

[0014] Preferably, the cigar tobacco is a cigar wrapper variety, and the lower leaves enter the maturity stage when the SPAD value is ≤35.

[0015] Preferably, the cigar tobacco is a cigar core variety, and the lower leaves enter the maturity stage when the SPAD value is ≤25.

[0016] Preferably, the chlorophyll content of the tobacco plant is measured using a chlorophyll meter.

[0017] Preferably, the

[0018]

[0019] In the formula, x i The chlorophyll content of the upper, middle, or lower leaves of the i-th plant of this variety; This represents the average chlorophyll content of the upper, middle, or lower leaves of this variety.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) At present, firstly, no method has been proposed for identifying the overall maturity of tobacco leaves, and secondly, no varieties with overall maturity have been selected. The method for identifying the overall maturity of cigar tobacco germplasm resources using the coefficient of variation established in this invention is original. In addition, this method has the advantages of being simple and fast compared to laboratory testing.

[0022] (2) This invention is the first to identify cigar germplasm resources (including wrapper and filler) suitable for whole-plant and semi-whole-plant harvesting, which can significantly reduce harvesting costs and provide important material support for efficient cigar production and sustainable development.

[0023] (3) Existing cigar germplasm resources are generally harvested in batches in major producing areas. This method has a long harvesting cycle and high labor costs. At the same time, the tobacco leaves are easily damaged and torn during handling, wrapping, and drying, which has an adverse effect on the quality of the tobacco leaves. The raw tobacco produced by this invention has a better appearance quality than the raw tobacco obtained by batch harvesting and is more suitable for making wrappers.

[0024] (4) Based on the current development status of cigar tobacco in my country, this invention scientifically designs experiments, conducts in-depth investigations in production areas, performs long-term tracking and observation, measures a large amount of maturity data, studies and formulates an efficient and accurate method for identifying the overall maturity of cigar tobacco leaves, and screens cigar tobacco germplasm resources suitable for whole / semi-whole plant harvesting, providing an important reference for the efficient production and sustainable development of cigar tobacco. Attached Figure Description

[0025] Figure 1 Effects of drying the whole ZX164 germplasm before and after processing; left: ZX164 before drying, right: ZX164 after drying.

[0026] Figure 2 The effect of harvesting and drying the lower, middle and upper parts of the tobacco leaves of variety ZX164 in one go; from left to right, the lower leaves, middle leaves, and upper leaves are shown.

[0027] Figure 3 The effects of harvesting ZX164 in stages and harvesting and drying whole plants: left shows ZX164 harvested in stages, right shows ZX164 harvested whole plants. Detailed Implementation

[0028] The technical solutions provided by the present application are described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by those skilled in the art to which the present application belongs.

[0030] Some related technical terms or scientific terms in the present application are explained as follows:

[0031] Upper leaves refer to the top leaves (top 3-4 leaves) and the upper two layers of leaves (3-4 leaves below the top leaves) of the tobacco plant;

[0032] Middle leaves refer to the waist leaves (about 5 leaves in the middle of the tobacco plant);

[0033] Lower leaves refer to the bottom leaves (about 3 leaves at the bottom of the tobacco plant) and the lower two layers of leaves (about 3 leaves above the bottom leaves) of the tobacco plant;

[0034] Initial flowering period refers to the date when 50% of the central flowers of the tobacco plants in the field open;

[0035] Whole plant harvesting refers to cutting the plants after the whole plant matures, removing the bottom 3 leaves, and directly entering the drying room for drying;

[0036] Half-plant harvesting refers to harvesting the lower 5-7 leaves twice and harvesting the remaining part after the upper leaves mature.

[0037] In the examples of the present application, unless otherwise specified, the test methods are conventional methods in the art, and the reagents, instruments and materials used can be obtained through commercial channels. The National Tobacco Germplasm Resource Mid-term Bank has preserved 345 core resources of cigar tobacco germplasm, which is the largest and most comprehensive resource of cigar tobacco germplasm in China, providing a rich material basis for the research.

[0038] Example 1

[0039] Experiments were set up in Qingdao, Shandong and Deyang, Sichuan in 2020, which are two important ecological points. In order to ensure that the test materials are representative, ensure that the growth conditions of the test seedlings are consistent, the growth is consistent, and reduce the test error, the technical scheme adopted includes the following steps:

[0040] I. Field planting

[0041] 1. Germplasm source

[0042] The seeds used in the experiment are 185 core resources of cigar tobacco germplasm, which come from the National Tobacco Germplasm Resource Mid-term Bank and the Sichuan Provincial Cigar Tobacco Germplasm Resource Bank.

[0043] 2. Test site and time

[0044] The test was arranged in Jimo test farm of Qingdao, Shandong and Shifang cigar tobacco breeding base of Deyang, Sichuan, among which the transplanting time in Jimo was May 2020, and the transplanting time in Shifang was April and May 2020.

[0045] 3. Test design

[0046] The test adopted randomized block design with three repetitions. Each germplasm was planted in one row with 25 plants.

[0047] 4. Data investigation

[0048] According to the classification of jacket and core, the chlorophyll content of tobacco plants was measured by SPAD-502Plus chlorophyll meter at the maturity stage of cigar tobacco leaves. The measurement scheme is as follows: each germplasm is measured in three repetitions, five plants are measured in each repetition, and the chlorophyll content of the middle leaves of the upper, middle and lower parts of each plant is measured.

[0049] When the SPAD value of the lower leaves of jacket tobacco is less than or equal to 35, and the SPAD value of the lower leaves of core tobacco is less than or equal to 25, the chlorophyll content of the leaves of the upper, middle and lower parts of the whole plant is measured.

[0050] The number of leaves of each germplasm was counted at the initial flowering stage, and the standard is specified in Tobacco Germplasm Resource Description Specification and Data Standard.

[0051] 5. Seeding and seedling

[0052] The existing cigar tobacco germplasm resources are classified according to types, sowed in the greenhouse, and the seedling emergence is observed. The cultivation environment is adjusted in time to ensure the emergence rate. After a month, false planting is carried out, and the greenhouse temperature is adjusted in time to reduce the temperature difference between indoor and outdoor, so that the plants can quickly adapt to the field environment after transplanting, shorten the seedling time, and enhance the resistance to rain, low temperature and strong wind.

[0053] 6. Land preparation and ridging

[0054] Most of the main production areas of cigar tobacco planting in China have acidic soil, and lime is needed to adjust the pH of the soil to the most suitable soil pH value of 5.5-6.5 for cigar tobacco before planting. The ridging generally starts 15-30 days before transplanting. The ridging position is determined according to 1.1 meter row spacing to ensure wide ditch and narrow ridge, straight ridge and flat ditch, and uniform depth for convenient irrigation.

[0055] 7. Transplanting

[0056] Transplanting is carried out in weather with moderate temperature and mild sunlight, with row spacing of 1.1m x 0.4m. Water is poured in time after transplanting, and seedling checking and replanting are completed within one week.

[0057] 8. Fertilization and irrigation

[0058] Specialized fertilizer for cigar tobacco is used. Base fertilizer: 250 kg of cigar tobacco bio-organic fertilizer (pure nitrogen 4.5 kg / 100 kg, N:P205:K20 = 1:1.2:2.5) is applied per mu using strip application. Water and fertilizer integration is used. The following points should be considered for water management: sufficient water for root establishment. After transplanting, sufficient water for root establishment is ensured according to soil moisture conditions to promote the survival and growth of tobacco seedlings. Control the water for root extension. Within 25 days after transplanting, appropriate water control is needed to promote root growth. Heavy watering for vigorous growth. After 35 days of transplanting, 1-2 times of irrigation is needed according to the weather and field growth of tobacco plants. Drip irrigation is preferred, and flooding irrigation should be avoided. Attention should be paid to flood control and drainage work after the rainy season to ensure that there is no water accumulation in the tobacco field. Stable irrigation for round top. After the top leaves are round, the soil moisture in the tobacco field is semi-arid to protect the leaves and prevent decline, ensuring normal maturation of the leaves. The chlorine content of the irrigation water source should be controlled to be below 10 mg / kg, otherwise the quality of the tobacco leaves will decrease, the burning property and ash color will deteriorate.

[0059] 9. Prevention of lodging

[0060] Cigar tobacco plants are tall, thin, and have a large node distance, which makes them prone to lodging. In the early stage, the soil is cultivated to prevent it; in the vigorous growth period (50-60 days), the height of the tobacco plant reaches about 170 cm, and a 200 cm or higher bamboo pole or wooden stick is used to bind the plant to fix it.

[0061] 10. Leaf maturity

[0062] Cigar tobacco generally grows in the field for 60-70 days before entering the mature stage. When the lower leaves reach the harvest standard, a SPAD-502 Plus chlorophyll meter is used to measure the chlorophyll content of the leaves.

[0063] II. Data statistics

[0064] The measured data is entered into DPS according to the type of cigar, and the average and standard deviation of chlorophyll content of the upper, middle and lower leaves of each accession are calculated. The average number of leaves of each accession is calculated. Further, the coefficient of variation of each accession is calculated. The formula for calculating the coefficient of variation is as follows:

[0065]

[0066] The smaller the coefficient of variation, the smaller the degree of variation. When performing data statistical analysis, if the coefficient of variation is greater than 15%, it is considered that the data may not be normal and should be excluded. According to this principle, when applied to cigar tobacco, the coefficient of variation can objectively compare the overall maturity difference of varieties, and the germplasm with a coefficient of variation less than 15% indicates consistent overall maturity, which can provide reference for subsequent whole plant harvesting of cigar tobacco. Germplasm with less than 17 leaves has limited yield and is not easy to promote in production, so the number of leaves greater than or equal to 17 is used as a limiting condition for whole plant and semi-whole plant harvesting germplasm. In addition, the coefficient of variation of chlorophyll content in middle and upper leaves less than 11.7% is used as a condition for semi-whole plant harvesting.

[0067] III. Results analysis

[0068] 1. Analysis of whole plant harvesting materials

[0069] Through comprehensive analysis of the overall maturity of 185 germplasms in two places and three periods, the smallest coefficient of variation of maturity was 11.81%, which was Weierxiaoliuye, a core material with only 13 leaves; the largest coefficient of variation of maturity was 35.99%, which was Burley 21, a jacket material with 22 leaves. These two materials performed very stably in two places and three periods. The average coefficient of variation of maturity of 185 germplasms was 18.78%, of which the germplasm with a coefficient of variation less than 15% accounted for 11.35%. Considering the yield demand of production, the number of leaves greater than or equal to 17 was used as a limiting condition, and the germplasm that met the condition was 106, the smallest coefficient of variation of maturity was 12.69%, which was Xiangtan Dixiyaopila, a core material; the largest coefficient of variation of maturity was still Burley 21. The average coefficient of variation of maturity of 106 germplasms was 18.96%, and the germplasm with consistent overall maturity and a coefficient of variation less than 15% was 8 (see Table 1, Table 1 continuation table), which were Xiangtan Dixiyaopila, Friedrichstaier, Unknown Cigar, Connecticut-s98, Tangpeng, Bamuliu, Havana 2000 and Habano.

[0070] Table 1 Cigar Tobacco Germplasm Resources Suitable for Whole Plant Harvesting

[0071]

[0072] Table 1 Cigar Tobacco Germplasm Resources Suitable for Whole Plant Harvesting (Continuation Table)

[0073]

[0074] 2. Analysis of semi-whole plant harvesting materials

[0075] Cigar leaves matured from bottom to top, and the corresponding harvesting is also from bottom to top. If there is no whole mature material, then screening semi-whole mature material is suitable for semi-whole harvesting. When the lower leaves are harvested piece by piece, the middle and upper leaves can be harvested in whole, thereby reducing most of the harvesting costs. In addition, relevant studies have shown that stem harvesting is beneficial to improving the quality of tobacco leaves. Therefore, screening suitable semi-whole harvesting materials is of great significance. Considering that the coefficient of variation of maturity of the upper and middle parts will be smaller than that of the upper, middle and lower parts, because cigar leaves mature from bottom to top, and the SPAD value of chlorophyll gradually increases from bottom to top, and the critical value of whole plant maturity coefficient of variation is 15%, the critical germplasm for whole plant harvesting is ZX164, i.e. Habano, and the semi-whole plant maturity coefficient of variation is 11.68% (see Table 2, Table 2 continuation table), so the critical value of semi-whole plant maturity coefficient of variation is set to 11.7%.

[0076] Table 2 Cigar tobacco germplasm resources suitable for semi-whole plant harvesting

[0077]

[0078]

[0079] Table 2 Cigar tobacco germplasm resources suitable for semi-whole plant harvesting (continued)

[0080]

[0081] The maturity of 185 germplasms in two places and three periods of semi-whole plant (middle and upper leaves) was analyzed comprehensively, and the minimum coefficient of variation of maturity was 7.41%, which was Zrenjanin, belonging to tobacco clothing material, and the number of leaves was 12.8; the maximum coefficient of variation of maturity was 22.76%, which was TN86, belonging to tobacco clothing material, and the number of leaves was 23.1. The average coefficient of variation of maturity of the upper part of the 185 germplasms was 13.28%, of which the germplasm with a coefficient of variation of maturity less than 11.7% accounted for 24.86%. When the number of leaves was greater than or equal to 17, the germplasm that met the conditions was 106, the minimum coefficient of variation of maturity was 8.83%, which was Tangpeng, belonging to tobacco core material; the maximum coefficient of variation of maturity was still TN86. The average coefficient of variation of maturity of the 106 germplasms was 13.33%, and the germplasm with consistent maturity and a coefficient of variation of maturity less than 11.7% was suitable for semi-whole plant harvesting.

[0082] Example 2

[0083] Whole plant harvesting and curing effect analysis

[0084] A kind of germplasm ZX164, namely Habano is selected to carry out whole plant curing test.ZX164 is the biggest in the maturity variation coefficient of the 8 germplasms suitable for whole plant harvesting, if it can be whole plant harvested and cured, the remaining 7 germplasms can also be whole plant cured.The germplasm suitable for whole plant harvesting is suitable for half whole plant harvesting.At the same time, in the 24 germplasms suitable for half whole plant harvesting, the maturity variation coefficient of ZX164 is also the largest, if ZX164 can be half whole plant harvested, the remaining 23 germplasms can also be half whole plant harvested.So in this sense, selecting ZX164 to carry out whole plant curing test is representative.

[0085] ZX164 enters the maturity period, the leaf blades of the upper, middle and lower three parts are mature and consistent Figure 1 , the whole plant curing effect is good Figure 1 . After the whole plant harvesting and curing and the half whole plant harvesting and curing of ZX164 are completed in the curing house, the original tobacco sample Figure 2 is obtained, which shows that the leaf blades of the upper, middle and lower three parts of the whole plant harvesting and curing are brown, the color of the upper leaves is slightly deeper than that of the lower leaves, the leaf surface organization is fine, and the integrity is good.The appearance of the middle leaves of ZX164 after half whole plant harvesting and curing and centralized harvesting and curing is compared Figure 3 and Table 3, and it is found by the inspection of the Tobacco Industry Product Quality Supervision and Inspection Test Center of the Ministry of Agriculture and Rural Affairs that the color of the once harvesting sample is slightly deeper than that of the half whole plant harvesting sample, the leaf surface organization is finer, the identity is thinner, the single leaf weight is smaller, the color is stronger, more uniform, the integrity is better, and the vein phase is better, that is, the appearance quality of the once harvesting and curing ZX164 is better than that of the half whole plant harvesting and curing ZX164, and it is more suitable for making jacket.

[0086] Table 3 Appearance quality of ZX164 under different treatments

[0087]

[0088]

[0089] Example 3

[0090] Cost comparison analysis of harvesting and curing

[0091] At present, cigar tobacco is harvested in several times, generally 6 times. According to the field investigation, in Shifang City of Sichuan Province, tobacco farmers employ manual harvesting of cigar tobacco, and 2-3 people are needed for manual harvesting of one mu of land, and the labor cost is about 120 yuan per mu. Due to the high temperature in the field, the cigar tobacco needs to be transported to the drying room for threading, and agricultural mechanical transport vehicles are needed. The single transport within 5 kilometers needs a transport fee of 50 yuan, and the medium-sized transport vehicle needs to go back and forth twice for one harvesting, and the transport cost is about 100 yuan. The harvesting link cost is (120+100) x 6≈1300 yuan. In the drying room, the threading link, from threading to shelving and unshelving, the labor cost is 2.2 yuan per rod (threading 1.5 yuan per rod, shelving 0.3 yuan per rod, unshelving 0.4 yuan per rod), one rod is about 40 pieces of tobacco, and according to 1500 plants per mu of land, an average of 17 pieces per plant can be harvested, one mu of land is about 640 rods, and the calculation can get the labor cost of the drying link of about 1400 yuan, and the total labor and transport cost of one mu of land is about 2700 yuan. In the case of whole-plant harvesting of cigar tobacco varieties, one mu of land needs about 4-5 people for whole-plant harvesting, and the cost is about 300 yuan, and the medium-sized transport vehicle needs to transport back and forth four times, about 200 yuan. The harvesting link cost is about 500 yuan. In the drying link, according to the calculation of four plants per rod, the labor cost of threading is saved, and simple fixing can be directly performed. The labor cost is 0.5 yuan per rod, and the shelving and unshelving cost is 0.7 yuan per rod (shelving 0.3 yuan per rod, unshelving 0.4 yuan per rod). According to the previous calculation of 1500 plants per mu of land, one mu of land can be used for about 375 rods, and the calculation can get the labor cost of the drying link of about 450 yuan, and the total labor and transport cost of whole-plant harvesting and drying is about 950 yuan, which greatly saves the time cost and labor cost. Under the background of agricultural modernization, mechanized harvesting is developing rapidly, and in the future, mechanized harvesting will provide more powerful power for reducing labor and cost. Compared with the harvesting and drying of several times, the harvesting and drying cost of whole-plant harvesting and drying is reduced from 2700 yuan per mu to 950 yuan per mu, and the harvesting and drying cost is significantly reduced (see Table 4).

[0092] Table 4 Comparison of harvesting costs of different drying methods

[0093]

[0094] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method of identifying overall maturity of a cigar seed resource, characterized in that, It comprises the following steps: At the mature stage of the cigar, the chlorophyll content of the upper, middle and lower leaves of the cigar is measured; the average value and the coefficient of variation of the chlorophyll content of the upper, middle and lower leaves of the variety are calculated, and when the average coefficient of variation of the whole plant is less than 15%, the variety is identified as a whole plant maturity consistent variety, and the whole plant can be harvested; The cigar is a variety for jacket use, and the SPAD value of the lower leaves is less than or equal to 35 to enter the mature stage; The cigar is a variety for core use, and the SPAD value of the lower leaves is less than or equal to 25 to enter the mature stage; The cigar is a variety with an average leaf number of greater than or equal to 17 leaves. Coefficient of variation = ×100%; In the formula, xi is the chlorophyll content of the upper, middle or lower leaves of the i th plant of the variety; is the average value of the chlorophyll content of the upper, middle or lower leaves of the variety. The average leaf number is counted at the initial flowering stage of the tobacco plant.

2. The method for identifying overall maturity of a cigar seed resource according to claim 1, characterized in that, The chlorophyll content of the tobacco plant is measured by a chlorophyll meter.

3. The method for identifying overall maturity of a cigar seed resource according to claim 1, characterized in that, ​

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