阅读说明：本技术 一种基于形态特征的k326品种田间识别方法 (K326 variety field identification method based on morphological characteristics ) 是由 谢新乔 杨继周 陈超 卢茂禄 宋成 李湘伟 朱云聪 胡保文 梅玲丽 伍显录 田育 于 2020-12-24 设计创作，主要内容包括：本发明涉及一种基于形态特征的K326品种田间识别方法,属于烤烟种植领域,本发明提供了针对苗期、移栽还苗后、团棵期、成熟期K326品种田间识别方法,具体如下：(1)苗期识别：a.观察生根期叶形,b.观察特定叶位叶尖和侧脉,c.观察种子包衣颜色；(2)移栽还苗后识别：a.观察特定叶位叶尖和侧脉,b.观察心叶叶尖和叶形,c.观察特定叶位叶形；(3)团棵期识别：a.观察叶型和叶尖,b.观察侧翼和翼延；(4)成熟期识别：a.观察烟株中下部叶叶面形态和节距,b.观察下部叶侧翼、翼延叶形和叶尖,c.观察上部叶侧翼。本发明能有效提高K326品种识别效率,可在田间快速识别K326品种,操作简单、易推广。(The invention relates to a K326 variety field identification method based on morphological characteristics, belongs to the field of flue-cured tobacco planting, and provides a K326 variety field identification method aiming at seedling stage, transplanting and seedling returning stage, bulk stage and mature stage, which comprises the following steps: (1) seedling stage identification: a. observing the shape of the leaves in the rooting period, b, observing the tips and side veins of the specific leaves, and c, observing the coating color of the seeds; (2) and (3) identifying after transplanting and returning seedlings: a. observing the tip and side veins of a specific leaf position, b, observing the tip and shape of a heart leaf, and c, observing the shape of a specific leaf position; (3) identifying the colony stage: a. observing the blade profile and the blade tip, and b, observing the side wing and the wing extension; (4) and (3) identifying the maturation period: a. observing the shape and pitch of the leaf surface of the middle lower part of the tobacco plant, b, observing the side wing, the wing extending shape and the leaf tip of the lower part of the leaf, and c, observing the side wing of the upper part of the leaf. The method can effectively improve the K326 variety identification efficiency, can quickly identify the K326 variety in the field, and is simple to operate and easy to popularize.)

1. A K326 variety field identification method based on morphological characteristics is characterized by comprising the following steps: the method is used for seedling stage identification and specifically comprises the following steps:

observing the leaf shape in the rooting stage: most true leaf edges are in an inward rolling shape in the rooting period, the true leaf shapes except for heart leaves are in a wide oval shape, and the widest part of each leaf is positioned at the base of each leaf;

(ii) observe the specific leaf position apex and lateral veins: the blunt tip of the 3 rd or 4 th true leaf is cherry-shaped, the number of side veins is only 5-6 pairs, and the first pair of side veins on the leaf base is nearly vertical to the main vein, and the included angle is close to 90 degrees;

(iii) observing seed coating color: the seed coating is green;

the requirements (i) to (iii) are sufficient for determining K326, and the strain can be determined as K326.

2. A K326 variety field identification method based on morphological characteristics is characterized by comprising the following steps: the method is used for identifying transplanted seedlings after returning, and specifically comprises the following steps:

observing the specific leaf apex and lateral veins: the blunt tip of the 3 rd or 4 th true leaf is cherry-shaped, the number of side veins is only 5-6 pairs, and the first pair of side veins on the leaf base is nearly vertical to the main vein, and the included angle is close to 90 degrees;

(ii) Observation of the heart lobe tips and lobes: the apex of the heart blade is sharp, the blade profile is in an inverted oval shape, and the widest part of the blade is positioned at the upper part of the blade (namely from the base part to the apex 2/3);

(iii) observing specific leaf position leaf shape: a true leaf with a leaf length more than 3cm nearest to the heart leaf, wherein the leaf edge slowly shrinks from the base to the apex, the apex is blunt or sharp, the leaf shape is oval, the widest part of the leaf is at the base of the leaf, and the leaves at both sides of the main vein slightly upwarp towards the inner side of the main vein like a shield;

(iv) Observation of the flanks and winglets: the side wing of the base part of the leaf is 0-0.5cm, so that green mesophyll can not be seen almost and no wing extension exists;

the requirements (i) to (iii) are sufficient for determining K326, and (iv) is only an auxiliary judgment, and satisfying (i) to (iii) can determine that the strain is K326.

3. A K326 variety field identification method based on morphological characteristics is characterized by comprising the following steps: the method is used for identifying the head stage, and specifically comprises the following steps:

observing the blade profile and the blade tip: most leaf shapes are in a wide oval shape, the leaf surfaces shrink obviously, mesophyll among side veins is raised, and the leaf edges are in a wave shape; sharp tips of 2-3 blade tips close to the heart leaf, and blunt tips of the other blade tips;

(ii) viewing the side flaps and wing extensions: the width of the flank of the base part of the leaf is 0.5-2.0cm and is wavy; the wing extension is equal to the width of the side wing or slightly wider than the side wing, and the width is 0.5-2.5 cm;

(iii) observing and measuring the tobacco plant pitch: most of tobacco stems are covered by leaves, only a small amount of stems can be seen from the side surface of a tobacco plant, and the pitch is 2.5 +/-0.3 cm;

(i) and (ii) are sufficient requirements for determining K326, and (iii) is only an auxiliary determination, and satisfying (i) and (ii) at the same time can be determined as K326 variety.

4. A K326 variety field identification method based on morphological characteristics is characterized by comprising the following steps: the method is used for identifying the maturation period, and specifically comprises the following steps:

observing the shape and pitch of the middle and lower leaf surfaces of the tobacco plants: the shrinkage of the leaf surface is obvious, and the leaf shape is wide oval or elliptical; the tobacco plant pitch is uneven, and the pitch (4.5-6.8 cm) of the leaves at the middle upper part is obviously larger than that of the leaves at the middle lower part; the blades at the middle and lower parts are dense, the pitch is shorter and is 3.5-4.5cm, most blades cover the blades, and only a small amount of stalks can be seen; except for the bottom foot leaves, the side veins of the leaves sink and mesophyll among the side veins are raised;

(ii) viewing the under leaf flank, wing span and tip: the wing is narrower, the width is 0.8-2.3cm, the wing extension is equal to the width of the wing or slightly wider than the wing, and the width of the wing extension is 0.8-2.8 cm; the blade shape is wide ellipse, and the blade tip is blunt or sharp;

(iii) viewing the upper leaf flank: except for the top leaf, the difference between the width of the side wing and the width of the leaf is larger, and the width of the side wing is less than 1/2 of the width of the leaf;

(iv) observing fireworks: the inflorescence is concentrated, the corolla is pink, the stamens are degenerated, and the length of 5 stamen filaments is less than 1/2 of the length of pistils;

the K326 variety can be determined by satisfying (i) to (iii) as the requirement for determining the adequacy of the K326 variety, (iv) as the requirement for determining the adequacy of the K326 variety.

5. The method for identifying the K326 variety in the field based on the morphological characteristics as claimed in claim 1, which is characterized in that: the rooting period refers to the period from the 3 rd true leaf to the 6 th true leaf of the tobacco seedling, wherein the 3 rd or 4 th true leaf is inclined and vertical, and the size is as large as that of a cat ear; the wide oval shape means that the length of the leaf is 1.2-1.6 times of the width of the leaf, and the widest part is at the base of the leaf.

6. The method for identifying the K326 variety in the field based on the morphological characteristics as claimed in claim 2, which is characterized in that: the seedling returning after transplanting means that the withering phenomenon does not occur after the tobacco seedlings are transplanted, and 1-2 new leaves grow out; oval means that the length of the leaf is 1.6-2 times of the width of the leaf, and the widest part is at the base of the leaf; the inverted oval shape is the inverse of the oval shape.

7. The method for identifying the K326 variety in the field based on the morphological characteristics as claimed in claim 3, wherein the method comprises the following steps: the number of leaves is 12-13, the ratio of the transverse growth width to the longitudinal growth height of the tobacco plant is about 2:1, the plant shape is approximately spherical, and the central leaves are concave.

8. The method for identifying the K326 variety in the field based on the morphological characteristics as claimed in claim 4, wherein the method comprises the following steps: the mature period refers to the period from budding to the end of harvest of the tobacco plant.

9. The method for identifying the K326 variety in the field based on the morphological characteristics as claimed in claim 4 or 5, wherein the method comprises the following steps: the stamens are degenerated, only aiming at the large-area production in the field, and are not suitable for breeding materials.

10. The method for identifying the K326 variety in the field based on the morphological characteristics as claimed in any one of claims 1 to 9, wherein the method comprises the following steps: the identification method is suitable for field identification of K326 varieties in Yunnan tobacco regions, and is suitable for healthy tobacco plants which grow normally in the field and are free of disease infection.

Technical Field

The invention belongs to the field of flue-cured tobacco planting, and particularly relates to a K326 variety field identification method based on morphological characteristics.

Background

K326 was obtained by crossing and breeding McNairr 30 XNC 95, introduced from the United states in 1985, examined by the Committee for examining and determining varieties of crops in Yunnan province in 1988, and examined by the Committee for examining and determining varieties of tobacco in the nation in 1989. At present, the flue-cured tobacco variety with the second largest planting area in China is stable in the planting area of about 150 ten thousand acres per year, wherein the planting area of about 100 ten thousand acres per year in Yunnan. The variety has good evaluation of fragrance quality, sufficient fragrance amount, medium concentration, good miscellaneous gas, moderate strength, good irritation, comfortable aftertaste, strong combustibility and grey gray grey white. The K326 planted in Yunnan has pure and outstanding fresh and sweet flavor, good richness of tobacco fragrance, full and thick fragrance amount, high smoke concentration, good penetrability, light irritation and clean aftertaste; is one of important high-quality tobacco leaf raw materials of Chinese style cigarettes.

The planting history of K326 in China is more than 30 years, the K326 is mainly planted in Yunnan, the problems of heavy disease, poor stress resistance, difficult baking and the like generally exist in the field, so that the positivity of planting K326 by tobacco growers is not high, the phenomenon of mixed planting of non-conventional varieties in the field exists, and the purity of the K326 in the field is difficult to guarantee; the purity of the tobacco variety of the tobacco company cannot be expected in the tobacco purchasing and industrial and commercial handover processes, the brand image of the tobacco of the local tobacco company and the stability of the product formula of cigarette industry enterprises are seriously influenced, and the quality stability of cigarette products is further influenced. Therefore, the method is very important for guaranteeing the purity of the variety in the field, and the rapid and accurate identification of the flue-cured tobacco variety in the field is the key for guaranteeing the purity of the variety in the field. If the tobacco is found to be a non-specified variety in the field in the early growth stage of the field, the tobacco grower can be responsible for timely cleaning and pulling out the tobacco to perform additional planting on the specified variety (K326) so as to ensure the purity of the field variety; if the tobacco is found to be a non-specified variety in the middle and later growth stages of the field of flue-cured tobacco, the purity of the variety can be estimated, and references are provided for tobacco purchasing of tobacco companies and tobacco allocation of industrial enterprises.

At present, the research on flue-cured tobacco variety identification is mainly based on molecular markers, and the molecular markers on the DNA level are established by carrying out sRAP molecular calibration on the properties of tobacco or adopting rapD markers, so as to distinguish and identify tobacco varieties. However, the molecular calibration technology is complex to operate, has high requirements on quality of detection equipment and detection personnel, is high in detection cost, long in detection period and high in popularization and application difficulty, and is difficult to meet the actual requirements of current flue-cured tobacco production.

Disclosure of Invention

The invention aims to solve the technical problems and provides a method for quickly and accurately identifying a K326 variety according to morphological characteristics of tobacco plants in the seedling stage, the seedling return stage after transplantation, the bulk stage and the mature stage of flue-cured tobacco.

In order to realize the purpose, the invention is realized by the following technical scheme:

the method for identifying the K326 variety in the seedling stage in the field based on morphological characteristics specifically comprises the following steps:

observing the leaf shape in the rooting stage: most true leaf edges are in an inward rolling shape in the rooting period, the true leaf shapes except for heart leaves are in a wide oval shape, and the widest part of each leaf is positioned at the base of each leaf;

(ii) observe the specific leaf position apex and lateral veins: the blunt tip of the 3 rd or 4 th true leaf is cherry-shaped, the number of side veins is only 5-6 pairs, and the first pair of side veins on the leaf base is nearly vertical to the main vein, and the included angle is close to 90 degrees;

(iii) observing seed coating color: the seed coating is green; different colors of coating agents are used for different varieties of flue-cured tobacco seeds produced by a normal way (south breeding center and north breeding center), and the color is fixed between years. If the seeds do not contain the coating agent, the seeds are bred by the tobacco grower, and the seeds are necessarily non-conventional varieties.

The requirements (i) to (iii) are sufficient for determining K326, and the strain can be determined as K326.

Further preferably, the rooting period is that the tobacco seedling appears from the 3 rd true leaf to the 6 th true leaf, the 3 rd or 4 th true leaf is inclined and vertical, and the size is as the same as that of the cat ear; the wide oval shape means that the length of the leaf is 1.2-1.6 times of the width of the leaf, and the widest part is at the base of the leaf.

The method for identifying the K326 variety after transplantation and seedling return based on morphological characteristics comprises the following steps:

observing the specific leaf apex and lateral veins: the blunt tip of the 3 rd or 4 th true leaf is cherry-shaped, the number of side veins is only 5-6 pairs, and the first pair of side veins on the leaf base is nearly vertical to the main vein, and the included angle is close to 90 degrees;

(ii) Observation of the heart lobe tips and lobes: the apex of the heart blade is sharp, the blade profile is in an inverted oval shape, and the widest part of the blade is positioned at the upper part of the blade (namely from the base part to the apex 2/3);

(iii) observing specific leaf position leaf shape: a true leaf with a leaf length more than 3cm nearest to the heart leaf, wherein the leaf edge slowly shrinks from the base to the apex, the apex is blunt or sharp, the leaf shape is oval, the widest part of the leaf is at the base of the leaf, and the leaves at both sides of the main vein slightly upwarp towards the inner side of the main vein like a shield;

(iv) Observation of the flanks and winglets: the side wing of the base part of the leaf is 0-0.5cm, so that green mesophyll can not be seen almost and no wing extension exists;

the requirements (i) to (iii) are sufficient for determining K326, and (iv) is only an auxiliary judgment, and satisfying (i) to (iii) can determine that the strain is K326.

Further preferably, the transplanting and seedling returning means that the withering phenomenon does not occur after the tobacco seedlings are transplanted, and 1-2 new leaves grow out; oval means that the length of the leaf is 1.6-2 times of the width of the leaf, and the widest part is at the base of the leaf; the inverted oval shape is the inverse of the oval shape.

The field identification method of the group stage of the K326 variety based on morphological characteristics specifically comprises the following steps:

observing the blade profile and the blade tip: most leaf shapes are in a wide oval shape, the leaf surfaces shrink obviously, mesophyll among side veins is raised, and the leaf edges are in a wave shape; sharp tips of 2-3 blade tips close to the heart leaf, and blunt tips of the other blade tips;

(ii) viewing the side flaps and wing extensions: the width of the flank of the base part of the leaf is 0.5-2.0cm and is wavy; the wing extension is equal to the width of the side wing or slightly wider than the side wing, and the width is 0.5-2.5 cm;

(iii) observing and measuring the tobacco plant pitch: most of tobacco stems are covered by leaves, only a small amount of stems can be seen from the side surface of a tobacco plant, and the pitch is 2.5 +/-0.3 cm;

(i) and (ii) are sufficient requirements for determining K326, and (iii) is only an auxiliary determination, and satisfying (i) and (ii) at the same time can be determined as K326 variety.

Further preferably, the plant growth period is 12-13 leaves, the ratio of the transverse growth width to the longitudinal growth height of the tobacco plant is about 2:1, the plant shape is approximately spherical, and the heart leaves are concave.

The method for identifying the mature period of the K326 variety based on morphological characteristics comprises the following steps:

observing the shape and pitch of the middle and lower leaf surfaces of the tobacco plants: the shrinkage of the leaf surface is obvious, and the leaf shape is wide oval or elliptical; the tobacco plant pitch is uneven, and the pitch (4.5-6.8 cm) of the leaves at the middle upper part is obviously larger than that of the leaves at the middle lower part; the blades at the middle and lower parts are dense, the pitch is shorter and is 3.5-4.5cm, most blades cover the blades, and only a small amount of stalks can be seen; except for the bottom foot leaves, the side veins of the leaves sink and mesophyll among the side veins are raised;

(ii) viewing the under leaf flank, wing span and tip: the wing is narrower, the width is 0.8-2.3cm, the wing extension is equal to the width of the wing or slightly wider than the wing, and the width of the wing extension is 0.8-2.8 cm; the blade shape is wide ellipse, and the blade tip is blunt or sharp;

(iii) viewing the upper leaf flank: except for the top leaf, the difference between the width of the side wing and the width of the leaf is larger, and the width of the side wing is less than 1/2 of the width of the leaf;

(iv) observing fireworks: the inflorescence is concentrated, the corolla is pink, the stamens are degenerated, and the length of 5 stamen filaments is less than 1/2 of the length of pistils;

the K326 variety can be determined by satisfying (i) to (iii) as the requirement for determining the adequacy of the K326 variety, (iv) as the requirement for determining the adequacy of the K326 variety.

Further preferably, the mature period is from budding to the end of harvest of the tobacco plant.

Further preferably, stamens are degenerated, only aiming at field large-area production and not suitable for breeding materials.

The method is suitable for field identification of K326 varieties in Yunnan tobacco regions.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention provides morphological characteristic identification indexes aiming at different growth periods of the K326 flue-cured tobacco, can quickly, accurately and pertinently identify the K326 varieties in the field, has better practicability and effectively improves the identification efficiency of the K326 varieties.

2. The method has low requirements on the quality of detection equipment and identification personnel, is simple to operate, has low cost and is easy to popularize.

Drawings

FIG. 1 is a name of each part of a tobacco leaf.

FIG. 2 is a morphological feature diagram at the seedling stage; wherein 2-1 is a leaf shape chart of K326 in the rooting period; 2-2 is a leaf shape chart of a certain cloud line variety in the rooting period; 2-3 is the morphological characteristics of a K326 single plant; 2-4 is the form characteristic of a single plant of a certain cloud line variety; 2-5 is the color of the K326 coated seeds; 2-6 is the color of the coated seeds of a certain cloud series variety.

FIG. 3 is a morphological feature diagram of tobacco plants after transplantation and seedling return; wherein 3-1 is a morphological characteristic diagram of the tobacco plants after K326 seedling return; 3-2 is a morphological characteristic diagram of the tobacco plants after seedling return of a certain cloud line variety; 3-3 is a morphology chart of heart leaves after K326 seedling return; 3-4 is a heart leaf morphological picture after seedling return of a certain cloud line variety; 3-5 is a K326 seedling reduction back flank and wing extension morphological diagram; 3-6 are diagrams of the postemergence flank and the wing extension form of a certain cloud line variety.

FIG. 4 is a plot of the morphology of the clique; wherein 4-1 is a morphological characteristic diagram of the tobacco plant in the K326 agglomeration period; 4-2 is a morphological characteristic diagram of a tobacco plant in a cloud variety in the agglomeration period; 4-3 is an exploded view of the leaves of the K326 in the agglomeration period; 4-4 is an exploded view of the leaves of a cloud variety in the agglomeration stage; 4-5 are morphology diagrams of the K326 side wing and the wing extension in the bulk stage; 4-6 are flank and flank morphology diagrams of certain cloud line varieties in the block stage; 4-7 is a side view of the agglomeration period K326; 4-8 is the side view of a cloud variety in the colony stage.

FIG. 5 is a morphological feature of the maturation stage; wherein 5-1 is a K326 strain pattern diagram in the maturation period; 5-2 is a strain pattern diagram of a certain cloud line variety in a mature period; 5-3 is a K326 maturity lower leaf flank and wingspan morphological diagram; 5-4 is a morphological diagram of lower leaf flank and wing extension in the mature period of a certain cloud line variety; 5-5 is a K326 lower leaf surface morphology chart in the mature period; 5-6 is a morphological diagram of lower leaf surface of a certain cloud line variety in the mature period; 5-7 is a morphological diagram of the side wing and the wingspan of the upper leaves in the K326 maturation stage; 5-8 is a morphological diagram of upper leaf flank and wing extension of a certain cloud line variety in the mature period; 5-9 is K326 inflorescence and flower color morphological diagram; 5-10 is a pattern of inflorescences and colors of certain cloud line varieties; 5-11 is a morphology map of K326 flowers; 5-12 is a shape chart of a certain cloud series flower; 5-13 are morphological diagrams of male sterile flowers.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to be limiting in any way, and any modifications or alterations based on the teachings of the present invention are intended to fall within the scope of the present invention.

In this embodiment, taking the confirmed K326 variety in the yunnan tobacco field and a certain cloud system variety which is frequently mixed with the K326 variety by farmers in the field as an example, the K326 variety is identified by using the form feature-based K326 variety field identification method of the present invention.

Example 1: identifying K326 varieties in flue-cured tobacco seedling stage

The rooting stage refers to the stage from the 3 rd true leaf to the 6 th true leaf of the tobacco seedling, wherein the 3 rd or 4 th true leaf is inclined and vertical, and the size is as large as that of the ear of cat. The method is used for field identification by taking a K326 variety which is confirmed in a Yunnan tobacco field and a tobacco plant in a seedling stage of a certain cloud series variety as materials, and comprises the following steps:

observing the leaf shape in the rooting stage: most true leaves in the rooting period are in the shape of inward rolling, the true leaves except heart leaves are in the shape of wide oval (the wide oval means that the length of the leaf is 1.2-1.6 times of the width of the leaf), and the widest part of the leaf is at the base of the leaf. (ii) observe the specific leaf position apex and lateral veins: the blunt tip of the 3 rd or 4 th true leaf is in a cherry mouth shape, the number of side veins is only 5-6 pairs, and the first pair of side veins of the leaf base is nearly vertical to the main vein, and the included angle is close to 90 degrees. (iii) observing seed coating color: the seed coating color is green. Different colors of coating agents are used for different varieties of flue-cured tobacco seeds produced by a normal way (south breeding center and north breeding center), and the color is fixed between years. If the seeds do not contain the coating agent, the seeds are bred by the tobacco grower, and the seeds are necessarily non-conventional varieties. The conditions (i) to (iii) are necessary for determining K326 to be sufficient.

As shown in FIG. 2, the tobacco strain at the seedling stage satisfies (i) to (iii) at the same time, and it is judged as a K326 variety, otherwise it is judged as a non-K326 variety.

Example 2: identifying K326 varieties after flue-cured tobacco transplanting and seedling returning

The seedling returning after transplanting means that the withering phenomenon does not occur after the tobacco seedlings are transplanted, and 1-2 new leaves grow out; oval means that the length of the leaf is 1.6-2 times of the width of the leaf, and the widest part is at the base of the leaf; the inverted oval shape is the inverse of the oval shape. The method is used for field identification by taking the confirmed K326 varieties in the Yunnan tobacco field and tobacco plants after transplanting and seedling returning of certain cloud line varieties as materials, and comprises the following steps:

observing the specific leaf apex and lateral veins: the blunt tip of the 3 rd or 4 th true leaf is in a cherry mouth shape, the number of side veins is only 5-6 pairs, and the first pair of side veins of the leaf base is nearly vertical to the main vein, and the included angle is close to 90 degrees. (ii) Observation of the heart lobe tips and lobes: the apex of the heart blade is sharp, the blade profile is in the shape of an inverted oval, and the widest point of the blade is at the upper part of the blade (i.e. from the base of the blade to the tip 2/3). (iii) observing specific leaf position leaf shape: the leaf edge of a true leaf with a leaf length of more than 3cm nearest to the heart leaf is slowly contracted from the base to the apex, the apex is blunt or sharp, the leaf shape is oval, the widest part of the leaf is at the base of the leaf, and the leaves at both sides of the main vein slightly warp towards the inner side of the main vein like a shield. (iv) Observation of the flanks and winglets: the side wing of the base part of the leaf is 0-0.5cm, so that green mesophyll can not be seen almost and no wing extension exists; the conditions (i) to (iii) are necessary for determining the adequacy of K326, and (iv) is only an auxiliary judgment.

As shown in FIG. 3, the tobacco strain satisfies (i) to (iii) at the same time, and is judged as K326, otherwise, it is judged as a non-K326.

Example 3: identification of K326 varieties in flue-cured tobacco group period

The number of leaves is 12-13, the ratio of the transverse growth width to the longitudinal growth height of the tobacco plant is about 2:1, the plant shape is approximately spherical, and the central leaves are concave. The method is used for field identification by taking the confirmed K326 variety and the tobacco plant in the cloud series variety group period in the Yunnan tobacco district as materials, and comprises the following steps:

observing the blade profile and the blade tip: most leaf shapes are in a wide oval shape, the leaf surfaces shrink obviously, mesophyll among side veins is raised, and the leaf edges are in a wave shape; the apex of 2-3 blades close to the heart leaf is sharp, and the apex of the other blades is blunt. (ii) viewing the side flaps and wing extensions: the width of the flank of the base part of the leaf is 0.5-2.0cm and is wavy; the wing extension is equal to the width of the side wing or slightly wider than the side wing, and the width is 0.5-2.5 cm; (iii) observing and measuring the tobacco plant pitch: most of tobacco stems are covered by leaves, only a small amount of stems can be seen from the side surface of a tobacco plant, the pitch is small, and the pitch is 2.5 +/-0.3 cm. (i) and (ii) are necessary conditions for determining K326 to be sufficient, and (iii) is only an auxiliary judgment.

As shown in FIG. 4, the tobacco strain satisfies both (i) and (ii), and can be determined as K326 variety, otherwise, it is determined as non-K326 variety.

Example 4: identification of K326 varieties in flue-cured tobacco mature period

The mature period refers to the period from budding to the end of harvest of the tobacco plant. The method is used for field identification by taking a K326 variety and a tobacco plant of a cloud line variety in the mature period, which are confirmed in a Yunnan tobacco district, as materials, and comprises the following steps:

observing the shape and pitch of the middle and lower leaf surfaces of the tobacco plants: the shrinkage of the leaf surface is obvious, and the leaf shape is wide oval or elliptical; the tobacco plant pitch is uneven, and the pitch (4.5-6.8 cm) of the leaves at the middle upper part is obviously larger than that of the leaves at the middle lower part; the blades at the middle and lower parts are dense, the pitch is shorter and is 3.5-4.5cm, most blades cover the blades, and only a small amount of stalks can be seen; except for the bottom foot leaves, the side veins of the leaves sink and mesophyll among the side veins are raised; (ii) viewing the under leaf flank, wing span and tip: the wing is narrower, the width is 0.8-2.3cm, the wing extension is equal to the width of the wing or slightly wider than the wing, and the width is 0.8-2.8 cm; the blade shape is wide ellipse, and the blade tip is blunt or sharp; (iii) viewing the upper leaf flank: except for the top leaf, the difference between the width of the side wing and the width of the leaf is larger, and the width of the side wing is less than 1/2 of the width of the leaf; (iv) observing fireworks: the inflorescence is concentrated, the corolla is pink, the stamens are degenerated, and the length of 5 stamen filaments is less than 1/2 of the length of pistils; wherein. The stamen degeneration only aims at the large-scale production in the field and is not suitable for breeding materials. The (i) to (iii) are the conditions necessary for determining the K326 variety, and the (iv) is the condition necessary for determining the K326 variety, that is, the fireworks of the K326 variety must meet the characteristics, but the fireworks of the K326 variety do not necessarily meet the characteristics.

As shown in FIG. 5, the tobacco strain satisfies (i) to (iii) at the same time, and is judged as K326 strain, otherwise, it is judged as non-K326 strain.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.