A method for breeding all-female varieties of industrial hemp

Abstract

The present invention provides a method for breeding all-female varieties of industrial hemp, which comprises the following steps: after land preparation of an isolated plot, seeds of male-inducing plants are sown in early April, and male-inducing plants are grown after two transplantings; seeds of field plants are sown in early to mid-May, and field plants are grown after two transplantings, and artificial male induction is performed in early to mid-June, and after three field pollinations, field plant grains are harvested in early October. The present invention adopts means such as staged sowing, seedling raising in seedling nutrient blocks, two transplantings, male-inducing plants and batch management of field plants, chemical male induction, artificial pollination, etc., to effectively solve the technical problem of breeding all-female varieties of industrial hemp.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial hemp all-female variety breeding, and specifically relates to an industrial hemp all-female variety breeding method. Background Art

[0002] Hemp (Cannabis sativa L.) is a multi-purpose crop, widely used in textile, papermaking, edible oil, functional health food, cosmetics, medicine, bioenergy, building materials, new bio-composite materials and other industries, which can be said to involve all aspects of people's lives, such as "clothing, food, housing, transportation and use". Internationally, the hemp variety with a hallucinogenic and addictive toxic component tetrahydrocannabinol (THC) content of less than 0.3% (percentage of dry matter in female plant spikes) and no drug use value is called industrial hemp. Because of its high economic development and utilization value, and the various advantages of the crop itself in ecological protection, such as strong resistance to pests and diseases, high absorption of heavy metals, environmentally friendly new materials, agricultural carbon sinks, etc. In recent years, many countries have attached increasing importance to the production and development of industrial hemp, and research has been active.

[0003] At present, most of the industrial hemp varieties produced and promoted in my country are dioecious. After pollination is completed, male plants need to be manually removed. The duration of emasculation is long, the workload is large, the investment cost is high, and the overall biological output is low due to the growth cycle of male plants. This problem has restricted the development of the industrial hemp industry to a certain extent, especially the development of the functional industrial hemp industry. There are very few domestic industrial hemp all-female varieties, and there is almost no promotion and application. The main reason is that the all-female variety breeding technology is difficult, the yield is small, and the environmental pollution is serious. Based on the current development situation, the present invention adopts staged sowing, indoor seedling cultivation, two transplanting, batch management, chemical male induction, artificial pollination and other means to effectively solve the technical problems of industrial hemp all-female variety breeding. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for breeding all-female varieties of industrial hemp in view of the deficiencies of the above-mentioned prior art. The method adopts means such as staged sowing, seedling cultivation in seedling nutrient blocks, two transplanting, inducing male plants and batch management of field plants, chemical male induction, artificial pollination, etc., which effectively solves the technical problems of breeding all-female varieties of industrial hemp.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for breeding all-female varieties of industrial hemp, the method comprising:

[0006] S1. Site selection: Select an isolated plot of land with no cannabis cultivation within 30 kilometers and apply 40 kg / mu of nitrogen, phosphorus and potassium compound fertilizer;

[0007] S2. Planting of male-inducing plants:

[0008] S201. Sowing of male-inducing plants:

[0009] In early April, industrial hemp seeds with evenly full grains were selected and soaked in clean water for 12 hours to obtain seeds for induced male plants to be sown;

[0010] Soaking the seedling nutrient blocks with clean water, squeezing out some of the water after the nutrient blocks are fully absorbed, obtaining the seedling nutrient blocks to be sown, poking holes in the seedling nutrient blocks to be sown, sowing one seed of the male-inducing plant to be sown in each of the seedling nutrient blocks to be sown, with a sowing depth of 1 cm, and after covering the seed holes, placing the sown seedling nutrient blocks in a seedling tray, and covering the seedling tray with a layer of plastic film, and growing at a temperature of 25° C.;

[0011] S202, first transplanting:

[0012] Take field soil and put it into the nutrient pot. When the male-induced plant seedlings grow 1 cm, move the nutrient blocks after emergence into the nutrient pot. Water the seedlings after transplanting and place them in an open-air place with sufficient light for growth. Water them once every 2 days.

[0013] S203, Second transplanting:

[0014] After the male-induced plant seedlings have grown in the nutrient pots described in S202 for 20 days, field soil is placed in the flowerpots and the amount of soil applied is 20 g / 100 kg. 土壤 The male-inducing plant seedlings in the nutrient pots are transplanted into the flower pots together with the soil, watered after transplanting, and placed in an open-air place with sufficient light to grow, thereby obtaining male-inducing plants;

[0015] S204. Management of male-inducing plants:

[0016] The spacing between the flower pots after transplanting was 50 cm, and watering was done every 3 days. Every 1 month, 2 g / plant of nitrogen, phosphorus and potassium compound fertilizer was applied while watering.

[0017] S3. Planting of plants in the field:

[0018] S301. Sowing of plants in the field:

[0019] In early to mid-May, select industrial hemp seeds with uniform and full grains and soak them in clean water for 12 hours to obtain seeds for field plants to be sown;

[0020] Soak the seedling nutrient block with clean water, squeeze out some water after the nutrient block is fully absorbed, hold the seedling nutrient block with medium strength until no water drips, and obtain the seedling nutrient block to be sown, poke holes in the seedling nutrient block to be sown, sow one seed of the field plant to be sown in each of the seedling nutrient blocks to be sown, and the sowing depth is 1 cm. After covering the seed eyes, place the sown seedling nutrient block in a seedling tray, and cover the seedling tray with a layer of plastic film, and grow at a temperature of 25°C;

[0021] S302, first transplanting:

[0022] Take the field soil and put it into the nutrient pot. When the field plant seedlings grow 1 cm, move the nutrient blocks after emergence into the nutrient pot. Water them after transplanting and place them in an open-air place with sufficient light for growth. Water them once every 2 days.

[0023] S303, Second transplanting:

[0024] After the field plant seedlings have grown in the nutrient pots in S302 for 20 days, the field plant seedlings in the nutrient pots are transplanted into the field with the soil, with a row spacing of 1.2 meters and a plant spacing of 1 meter, leaving 500 to 600 seedlings per mu, and watering them after transplanting to obtain field plants;

[0025] S304, Field Plant Management:

[0026] Timely tillage and weeding, no need to water unless there is a severe drought, and timely drainage in case of floods;

[0027] S4, attract males:

[0028] In early to mid-June, at the late stage of vegetative growth of the induced male plants described in S203, artificial chemical induced male plants are performed to obtain induced male plants;

[0029] The method of staggered sowing is adopted. The induced male plants are sown in early to mid-April, and the field plants are sown in early to mid-May. The induced male plants are sown 30-40 days earlier than the field plants to ensure that the flowering periods coincide.

[0030] The method of artificial chemical male induction is: firstly treat the male-induced plants with dark light for 12 hours, then spray the surrounding, top and axillary buds of the male-induced plants with a 1.5mmol / L Ag2S2O3 complex solution for 7 consecutive times, and then spray the 0.3g / L gibberellic acid GA3 solution once after 4 days;

[0031] Starting from the first spraying of the Ag2S2O3 complex solution, the male-inducing plants are kept in a dark light treatment for 12 hours every day until the end of pollination; that is, a dark light treatment for 12 hours and a light treatment for 12 hours every day;

[0032] The 12-hour dark light treatment every day is to ensure that the male-induced plants can bloom male flowers normally. If the dark light time is less than 12 hours a day, the male-induced plants will not bloom.

[0033] The spraying interval of the Ag2S2O3 complex solution is once every 4 days;

[0034] The preparation method of the Ag2S2O3 complex solution is as follows: adding distilled water a to AgNO3 and mixing them uniformly to obtain an AgNO3 solution; adding distilled water b to Na2S2O3·5H2O and mixing them uniformly to obtain a Na2S2O3 solution; pouring the AgNO3 solution into the Na2S2O3 solution while stirring, stirring uniformly until no white precipitate appears, to obtain an Ag2S2O3 complex solution;

[0035] The usage ratio of AgNO3, distilled water a, Na2S2O3·5H2O and distilled water b in the Ag2S2O3 complex solution is 2.55g:5L:11g:5L;

[0036] When spraying the pesticide to induce male fertilization, cover the ground where the flower pots are placed with waste newspapers, and dispose of the waste paper separately after the male fertilization is completed. Dispose of the soil in the flower pots separately after the pollination is completed to reduce the pollution of Ag ions to the environment.

[0037] S5. Pollination:

[0038] S501, first field pollination:

[0039] In early August, the first batch of induced male plants after induced male plants in S4 reaches the peak flowering period, the middle and upper flower spikes of the first batch of induced male plants that reach the peak flowering period are cut off, dried at a temperature of 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain the first batch of flower spike powder; at this time, the field plants are just in the early flowering stage, and the field plants in S303 in the early flowering stage are pollinated for the first time with an electric artificial pollinator; the unused pollen can be stored in a refrigerator at 0-5° C. and taken out for the next pollination;

[0040] S502, Second Field Pollination:

[0041] Cut off the middle and upper flower spikes of the first batch of male-induced plants that have reached the peak flowering period and continue to grow. One week after the first field pollination is completed, the second batch of male-induced plants that have reached the peak flowering period after the male-induced plants described in S4 reach the peak flowering period. Cut off the middle and lower flower spikes of the first batch of male-induced plants that have reached the peak flowering period and the middle and upper flower spikes of the second batch of male-induced plants that have reached the peak flowering period, concentrate them under the condition of drying at a temperature of 30° C. for 36 hours, crush and sieve the dried flower spikes to obtain the second batch of flower spike powder; use an electric artificial pollinator to perform a second field pollination on the field plants described in S303;

[0042] S503, the third field pollination:

[0043] One week after the second field pollination, the flower spikes of all the induced male plants are cut off, dried at 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain a third batch of flower spike powder; the field plants described in S303 are subjected to a third field pollination using an electric artificial pollinator;

[0044] S6. Harvest:

[0045] In early October, most of the seeds of field plants are mature and harvested. After harvesting, they are placed in a cool place for a week, then dried and threshed. They are then sorted, packaged and stored. Remember not to mix them with other hemp seeds.

[0046] Preferably, the mass fractions of N, P and K in the nitrogen-phosphorus-potassium compound fertilizer in S1, S203 and S204 are all 15%.

[0047] Preferably, the sowing amount of industrial hemp seeds described in S201 is 30 plants / acre.

[0048] Preferably, the water content of the nutrient blocks to be sown and seedlings raised in S201 and S301 is 60% to 70%.

[0049] Preferably, the specification of the nutrient pot in S202 is 16 cm×16 cm; the specification of the flower pot in S203 is 60 cm×60 cm.

[0050] Preferably, the mesh number of the sieving in S501 and S502 is 50 meshes.

[0051] Compared with the prior art, the present invention has the following advantages:

[0052] 1. The whole population of functional all-female industrial hemp varieties is female plants, without male flowers for pollination. To ensure the purity and all-female nature of the next generation population, female plants must be induced to bloom male flowers under strict isolation conditions to achieve pollination and fruiting. The present invention solves the following problems in the breeding process of all-female industrial hemp varieties: poor germination rate, inconsistent germination, serious seedling shortage; the male induction flowering period is not met, the pollen amount is insufficient, and the pollen vitality is weak; the male induction reagent causes soil environmental pollution; the pollination workload is large, the effect is not good, and the fruiting rate is not high; the variety quality is poor and the purity is insufficient.

[0053] 2. The present invention adopts seedling nutrient blocks for sowing, and after two transplanting, it is ensured that the seedlings emerge neatly and the seedlings are complete and strong. The staggered sowing is adopted, and the male-inducing plants are sown 30-40 days in advance to ensure that the flowering period coincides. The present invention adopts batch management, and the male-inducing plants are planted in flower pots and artificial shading intervention is used to ensure the success of male induction. Effective measures are taken before male induction to reduce the environmental pollution of chemical solvents. In artificial chemical male induction, a method of combining 1.5mmol / L Ag2S2O3 complex solution and 0.3g / L gibberellic acid GA3 solution is used to grasp the appropriate time and number of times, and the male induction effect is significant with minimal pollution. The present invention adopts the method of three pollen collection and three field pollination, which saves labor and time and has a high fruit setting rate.

[0054] The present invention is further described in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0055] Example 1

[0056] This embodiment was carried out in Jiajiazhuang, Fenyang City in 2020, with an experimental area of ​​3 mu.

[0057] The method for breeding all-female varieties of industrial hemp in this embodiment is as follows:

[0058] S1. Site selection: Select land within 30 kilometers where there is no cannabis cultivation, and apply 40 kg / mu of nitrogen, phosphorus and potassium compound fertilizer;

[0059] S2. Planting of male-inducing plants:

[0060] S201. Sowing of male-inducing plants:

[0061] In early April (April 4), industrial hemp seeds (Jinma No. 5) with uniform and full seeds were selected and soaked in clean water for 12 hours to obtain seeds of male-inducing plants to be sown;

[0062] Soak the seedling nutrient block with clean water, squeeze out some water after the nutrient block is fully absorbed, hold the seedling nutrient block with medium strength without dripping, and obtain the seedling nutrient block with a water content of 60% to be sown, poke holes in the seedling nutrient block to be sown, sow one seed of the male-inducing plant to be sown in each of the seedling nutrient blocks to be sown, the sowing depth is 1 cm, and after covering the seed holes, the sown seedling nutrient block is placed in a seedling tray, and a layer of plastic film is covered on the seedling tray, and the seeding is grown at a temperature of 25°C; the sowing amount is 30 plants / mu;

[0063] S202, first transplanting:

[0064] Put field soil into a 16cm×16cm nutrient pot, and when the male-inducing plant seedlings grow 1cm, move the nutrient blocks after emergence into the nutrient pots, water them after transplanting, and place them in an open-air place with sufficient light for growth, watering them once every 2 days;

[0065] S203, Second transplanting:

[0066] After the male-induced seedlings have grown in the nutrient pots described in S202 for 20 days, field soil is placed in a 60 cm×60 cm flowerpot and the amount of the fertilizer applied is 20 g / 100 kg. 土壤 The male-inducing plant seedlings in the nutrient pots are transplanted into the flower pots together with the soil, watered after transplanting, and placed in an open-air place with sufficient light to grow, thereby obtaining male-inducing plants;

[0067] S204. Management of male-inducing plants:

[0068] The spacing between the flower pots after transplanting was 50 cm, and watering was done every 3 days. Every 1 month, 2 g / plant of nitrogen, phosphorus and potassium compound fertilizer was applied while watering.

[0069] S3. Planting of plants in the field:

[0070] S301. Sowing of plants in the field:

[0071] In early to mid-May (May 13), industrial hemp seeds (Jinma No. 5) with uniform and full grains were selected and soaked in clean water for 12 hours to obtain seeds for field plants to be sown;

[0072] Soak the seedling nutrient block with clean water, squeeze out some water after the nutrient block is fully absorbed, hold the seedling nutrient block with medium strength without dripping, and obtain a seedling nutrient block to be sown with a water content of 60%, poke holes in the seedling nutrient block to be sown, sow one seed of the field plant to be sown in each of the seedling nutrient blocks to be sown, and the sowing depth is 1 cm. After covering the seed eyes, the sown seedling nutrient block is placed in a seedling tray, and a layer of plastic film is covered on the seedling tray, and the seedling tray is grown at a temperature of 25°C;

[0073] S302, first transplanting:

[0074] Take the field soil and put it into the nutrient pot. When the field plant seedlings grow 1 cm, move the nutrient blocks after emergence into the nutrient pot. Water them after transplanting and place them in an open-air place with sufficient light for growth. Water them once every 2 days.

[0075] S303, Second transplanting:

[0076] After the field plant seedlings have grown in the nutrient pots in S302 for 20 days, the field plant seedlings in the nutrient pots are transplanted into the field with the soil, with a row spacing of 1.2 meters and a plant spacing of 1 meter, leaving 500 seedlings per mu, watering them after transplanting, and growing them into field plants;

[0077] S304, Field Plant Management:

[0078] Timely tillage and weeding;

[0079] And there is no need to water unless there is a severe drought, and drainage is done in time in case of floods;

[0080] S4, attract males:

[0081] In early to mid-June (June 17), at the late stage of vegetative growth of the induced male plants in the flower pots in S203, artificial chemical induced male plants were subjected to induced male plants to obtain induced male plants;

[0082] The method of artificial chemical male induction is: firstly treat the male-induced plants with dark light for 12 hours, then spray the surrounding, top and axillary buds of the male-induced plants with a 1.5mmol / L Ag2S2O3 complex solution for 7 consecutive times, and then spray the 0.3g / L gibberellic acid GA3 solution once after 4 days;

[0083] Starting from the first spraying of the Ag2S2O3 complex solution, the male-inducing plants are kept in a dark light treatment for 12 hours every day until the end of pollination; that is, a dark light treatment for 12 hours and a light treatment for 12 hours every day;

[0084] The spraying interval of the Ag2S2O3 complex solution is once every 4 days;

[0085] The preparation method of the Ag2S2O3 complex solution is as follows: adding distilled water a to AgNO3 and mixing them uniformly to obtain an AgNO3 solution; adding distilled water b to Na2S2O3·5H2O and mixing them uniformly to obtain a Na2S2O3 solution; pouring the AgNO3 solution into the Na2S2O3 solution while stirring, stirring uniformly until no white precipitate appears, to obtain an Ag2S2O3 complex solution;

[0086] The usage ratio of AgNO3, distilled water a, Na2S2O3·5H2O and distilled water b in the Ag2S2O3 complex solution is 2.55g:5L:11g:5L;

[0087] Before spraying the male-inducing plants, dark light treatment was adopted. From spraying to the end of pollination, the male-inducing plants were kept in dark light treatment for 12 hours every day (i.e., 12 hours of dark light treatment and 12 hours of light treatment every day) to ensure the flowering of the plants; when spraying the male-inducing plants, the ground where the flower pots were placed was covered with waste newspapers, and the waste paper was treated separately after the male-inducing was completed. After the pollination was completed, the soil in the flower pots was treated separately to reduce the pollution of Ag ions to the environment;

[0088] This embodiment adopts staggered sowing to ensure that the flowering period coincides, and the male-inducing plants and the breeding plants (field plants) are planted and managed in batches, and the male-inducing plants are small in number and are relatively convenient to plant and manage in flower pots;

[0089] S5. Pollination:

[0090] S501, first field pollination:

[0091] In early August (August 6), the first batch of induced male plants after induced male plants in S4 reached the peak flowering period, the middle and upper flower spikes of the first batch of induced male plants that reached the peak flowering period were cut off, dried at a temperature of 30°C for 36 hours, and the dried flower spikes were crushed and sieved to obtain the first batch of flower spike powder; at this time, the field plants were just in the early flowering stage, and the field plants in S303 at the early flowering stage were pollinated for the first time using an electric artificial pollinator; the unused pollen was stored in a refrigerator at 0°C and taken out for the next pollination;

[0092] S502, Second Field Pollination:

[0093] Cut off the first batch of male-induced plants that have reached the peak flowering period after the middle and upper flower spikes are cut off, and the male-induced plants that have reached the peak flowering period after the first batch of male-induced plants in S4 continue to grow. One week after the first field pollination is completed, the middle and lower flower spikes of the male-induced plants that have reached the peak flowering period after the first batch of male-induced plants in S501 and the middle and upper flower spikes of the male-induced plants that have reached the peak flowering period after the second batch of male-induced plants are cut off, and dried at a temperature of 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain the second batch of flower spike powder; the field plants described in S303 are subjected to a second field pollination using an electric artificial pollinator;

[0094] S503, the third field pollination:

[0095] One week after the second field pollination, the flower spikes of all the induced male plants are cut off, dried at 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain a third batch of flower spike powder; the field plants described in S303 are subjected to a third field pollination using an electric artificial pollinator;

[0096] In daily breeding work, artificial pollination is usually done by using glass plates or cardboard to collect pollen, or by using a brush for artificial pollination. However, the breeding area is large, and conventional artificial pollination is difficult. If the male-inducing plants are planted in the field, firstly, dark light treatment cannot be adopted, and the flowering period cannot coincide with each other; secondly, the wind and rain interference of spraying pesticides in the field cannot be guaranteed; thirdly, the male-inducing solvent causes serious land pollution;

[0097] This embodiment adopts separate management of flower pots to induce male plants, which is simple, convenient and safe, ensuring that the flowering period is met and the amount of pollen is sufficient. According to the inconsistency of flowering of the plant group, pollen is collected in three batches to ensure the quantity and quality of pollen. The third field pollination cuts the flower spikes of all male-inducing plants, and adopts drying and crushing methods, which is more convenient than conventional pollen collection and has sufficient pollen, which is convenient for pollination by pollinator. Borrowing fruit tree pollinator for pollination is convenient and labor-saving.

[0098] Conventional artificial pollination methods have great difficulty in collecting pollen, a small amount of pollen collected, 15-20 people are invested per mu, and the pollination effect is average. However, the pollination method of the present invention has low difficulty in collecting pollen, a large amount of pollen collected, and only one person is invested per mu, and the pollination effect is good;

[0099] S6. Harvest:

[0100] In early October (October 6), most of the seeds of the field plants are mature, and the seeds of the field plants are harvested. After harvesting, they are placed in a cool place for a week, then dried and threshed, sorted, packaged and stored. Remember not to mix with other hemp seeds;

[0101] The mass fractions of N, P and K in the nitrogen-phosphorus-potassium compound fertilizers in S1, S203 and S204 are all 15%.

[0102] The average yield per mu of industrial hemp all-female seeds in this embodiment is 50 kilograms.

[0103] In addition, this example is an optimization test for the breeding method of industrial hemp all-female varieties:

[0104] (1) Germination method:

[0105] Conventional industrial hemp varieties are dioecious, have strong germination potential, and can germinate by both row sowing and broadcast sowing. However, most of the functional industrial hemp varieties with higher CBD content are imported germplasm resources from abroad, have poor germination potential, weak soil-penetrating ability, and almost no seedlings when sown directly in the field.

[0106] In 2018, 60 flowerpots were planted with "Jinma No. 5". Soil was taken from the field for the flowerpots, and seeds were directly sown into the flowerpots, with two seeds sown per pot. The sowing depth was about 1 cm. After sowing, water was applied, but the emergence rate was less than 20%.

[0107] In the spring of 2019, 2 mu of land in Jiazhuang, Fenyang was sown with "Jinma No. 5". After the land was watered, the seeds were sown, and the sowing depth was about 2 cm. The emergence rate was less than 3%.

[0108] Plant nursery nutrient blocks were used for sowing, with a sowing depth of 1 cm. The seedlings were transplanted in two times, enabling the varieties that did not emerge in field sowing to achieve the ideal effect of neat and strong seedlings.

[0109] 1. Germination and emergence test:

[0110] A germination and emergence test with different substrates was conducted. The test variety was "Jinma No. 5". The test had 4 treatments: field soil (A1), sandy soil (A2), flower nutrient soil (A3), and nursery nutrient blocks (A4), and two levels: sowing depth of 1 cm (B1) and sowing depth of 2 cm (B2), with two replicates. The seeds were sown in flowerpots, with 10 seeds sown per pot, and 2 pots for each treatment. The nutrient blocks were placed in seedling trays, with 1 seed sown per nutrient block. All were placed in an environment of 25°C, and a little water was sprayed every day to keep it moist. The germination and emergence situation is as follows in the table.

[0111] Table 1 Number of emerged seedlings after one week

[0112]

[0113] Table 2 Number of emerged seedlings after two weeks

[0114]

[0115] Analysis showed that: the differences among different substrate treatments reached an extremely significant level. The number of emerged seedlings after one week and two weeks both showed A1 < A2 < A3 < A4; the differences among sowing depth treatments also reached an extremely significant level. The number of emerged seedlings after one week showed B1 > B2 under substrates A1, A3, and A4, and the number of emerged seedlings after two weeks showed B1 > B2 under all substrates. Therefore, A4B1 (sowing with nutrient blocks at a depth of 1 cm) had the best emergence effect, with an emergence rate of 90%.

[0116] On this basis, an experiment on covering the film or not for A4B1 was conducted. Covering the film emerged two days earlier than not covering the film, and the emergence was neat and consistent.

[0117] During the variety experiment, at the same time, a comparison was made between directly transplanting the seedlings in the nursery blocks to the flowerpots once and transplanting the seedlings to the flowerpots twice after passing through the nutrient bowls. The results showed that after two transplantings, the seedlings were strong and grew faster. Moreover, it was relatively convenient to manage the seedlings in the nutrient bowls.

[0118] 2. Method of inducing male sterility:

[0119] Use Ag2S2O3 complex solution combined with GA3 solution to spray the top and axillary buds of industrial hemp. The spraying time starts from 12 hours of dark light. The concentration of Ag2S2O3 complex solution is 1.5mmol / L, and the number of spraying is 7 times.

[0120] The Ag2S2O3 complex solution ratio method reduces the amount of Na2S2O3 used and alleviates the damage of Na ions to plants.

[0121] The concentration of the sprayed GA3 solution is 0.3g / L, which is a relatively low concentration. The spraying time is 4 days after the spraying of the Ag2S2O3 complex solution.

[0122] (1) Test on the ratio of male induction solution:

[0123] The experiment set up two treatments: from the late stage of vegetative growth of male-induced plants, a 12-hour dark-light treatment was implemented every day (12 hours of light and 12 hours of darkness), and a 12-hour dark-light treatment was also implemented during the spraying period (12 hours of light and 12 hours of darkness);

[0124] Treatment 1: One week later, spraying (A1) was started;

[0125] Treatment 2: Two weeks later, spray when female flowers begin to develop (A2).

[0126] There are 4 concentrations of each treatment agent: 1mmol / L Ag2S2O3 complex solution (B1), 1.5mmol / L Ag2S2O3 complex solution (B2), 2mmol / L Ag2S2O3 complex solution (B3), and 2.5mmol / L Ag2S2O3 complex solution (B4).

[0127] Spray once every 3 days for 5 times in a row. The test results are shown in the following table.

[0128] Table 3 Male induction solution ratio test (average number of male flower spikes per plant)

[0129] B1 B2 B3 B4 A1 64 87 83 91 A2 42 67 72 77

[0130] Table 4 Male attractant solution ratio test (pollen amount)

[0131] B1 B2 B3 B4 A1 Smaller Larger Larger Larger A2 Small Small Small Smaller

[0132] The analysis showed that there was almost no difference in the number of male flower spikes and pollen amount between A1B2, A1B3 and A1B4, and the effects of other treatments were poor. However, the amount of AgNO3 used in A1B3 and A1B4 treatments was large, which wasted costs and caused great environmental pollution.

[0133] (2) Industrial hemp male induction test:

[0134] The seedlings were planted in a large flower pot with a diameter of 35 cm. The male induction agent was a Ag2S2O3 complex solution with a concentration of 1.5 mmol / L. The spraying was divided into two periods: period A: starting from 12 hours of dark light in the late vegetative growth period, the number of spraying was 5 times, 7 times, and 9 times respectively; period B: starting from the development of female flowers just after silking, the number of spraying was 3 times, 5 times, and 7 times respectively, and spraying was performed once every 4 days. The experiment was repeated twice.

[0135] Table 5 Effect of male induction test

[0136] deal with Spraying time Spraying times repeat Number of male flowers number of female flowers Pollen count A5 A 5 1 24 62 Smaller A5 A 5 2 32 45 Smaller A7 A 7 1 103 0 big A7 A 7 2 97 3 big A9 A 9 1 50 42 Larger A9 A 9 2 65 30 big B3 B 3 1 86 17 Small B3 B 3 2 80 23 Small B5 B 5 1 53 47 Small B5 B 5 2 48 39 Small B7 B 7 1 33 47 Smaller B7 B 7 2 29 45 Small

[0137] The results of the analysis showed that the differences among the treatments were extremely significant. The number of male flowers in the A7 treatment was the largest, reaching 100, and there were almost no female flowers. It was 20.48%, 73.91%, 98.02%, 222.58% and 257.14% higher than that of B3, A9, B5, B7 and A5, respectively, and was extremely significantly higher than that of A9, B5, B7 and A5. This indicated that spraying the 1.5mmol / L Ag2S2O3 complex solution from 12 hours after dark, once every 4 days, and spraying it for 7 times in a row had the best effect.

[0138] Although the effect of spraying only 1.5mmol / L Ag2S2O3 complex solution to induce male seeds is good, the pollen shedding time after male flowers bloom is relatively late. Most plants reach the peak flowering period about 1 month after male flowers bloom. This makes it difficult for induced male plants to meet the flowering period of field plants, and they need to be sown about 2 months apart. However, the climate environment in general areas cannot meet this condition. If induced male plants are sown earlier, the outdoor temperature will be low, affecting growth; if field plants are sown too late, the growth cycle will be long, affecting seed maturity. In this case, the male induction test was improved, and gibberellic acid GA3 was used to assist the male induction test.

[0139] (3) GA3-assisted male induction test

[0140] The male induction test was conducted in the late stage of industrial hemp growth. The light was kept dark for 12 hours every day (darkness 12h, light 12h), and a 1.5mmol / L Ag2S2O3 complex solution was sprayed once every 4 days for 7 consecutive times. After 4 days, a gibberellic acid GA3 solution was sprayed once. The concentrations of gibberellic acid GA3 were 0.1g / L, 0.3g / L, 0.5g / L, and 1g / L, respectively. The test results are shown in the following table.

[0141] Experiment on male induction assisted by gibberellic acid GA3

[0142]

[0143] The test results show that spraying 0.3g / L gibberellic acid GA3 solution once to assist in inducing male flowers can appropriately advance the flowering period of male flowers and slightly increase the amount of pollen.

[0144] Example 2

[0145] This example was carried out in Longquan Village, Wenshui County in 2021, with an experimental area of ​​2 mu.

[0146] The method for breeding all-female varieties of industrial hemp in this embodiment is as follows:

[0147] S1. Site selection: Select land within 30 kilometers where there is no cannabis cultivation, and apply 40 kg / mu of nitrogen, phosphorus and potassium compound fertilizer;

[0148] S2. Planting of male-inducing plants:

[0149] S201. Sowing of male-inducing plants:

[0150] In early April (April 2), industrial hemp seeds (Jinma No. 5) with uniform and full seeds were selected and soaked in clean water for 12 hours to obtain seeds of male-inducing plants to be sown;

[0151] Soak the seedling nutrient block with clean water, squeeze out some water after the nutrient block is fully absorbed, hold the seedling nutrient block with medium strength without dripping, and obtain a seedling nutrient block with a water content of 70% to be sown, poke holes in the seedling nutrient block to be sown, sow one seed of the male-inducing plant to be sown in each of the seedling nutrient blocks to be sown, the sowing depth is 1 cm, and after covering the seed holes, the sown seedling nutrient block is placed in a seedling tray, and a layer of plastic film is covered on the seedling tray, and the seeding is grown at a temperature of 25°C; the sowing amount is 30 plants / mu;

[0152] S202, first transplanting:

[0153] Put field soil into a 16cm×16cm nutrient pot, and when the male-inducing plant seedlings grow 1cm, move the nutrient blocks after emergence into the nutrient pots, water them after transplanting, and place them in an open-air place with sufficient light for growth, watering them once every 2 days;

[0154] S203, Second transplanting:

[0155] After the male-induced seedlings have grown in the nutrient pots described in S202 for 20 days, field soil is placed in a 60 cm×60 cm flowerpot and the amount of the fertilizer applied is 20 g / 100 kg. 土壤 The male-inducing plant seedlings in the nutrient pots are transplanted into the flower pots together with the soil, watered after transplanting, and placed in an open-air place with sufficient light to grow, thereby obtaining male-inducing plants;

[0156] S204. Management of male-inducing plants:

[0157] The spacing between the flower pots after transplanting was 50 cm, and watering was done every 3 days. Every 1 month, 2 g / plant of nitrogen, phosphorus and potassium compound fertilizer was applied while watering.

[0158] S3. Planting of plants in the field:

[0159] S301. Sowing of plants in the field:

[0160] In early to mid-May (May 15), industrial hemp seeds (Jinma No. 5) with uniform and full grains were selected and soaked in clean water for 12 hours to obtain seeds for field plants to be sown;

[0161] Soak the seedling nutrient block with clean water, squeeze out some water after the nutrient block is fully absorbed, hold the seedling nutrient block with medium strength without dripping, and obtain a seedling nutrient block to be sown with a water content of 70%, poke holes in the seedling nutrient block to be sown, sow one seed of the field plant to be sown in each of the seedling nutrient blocks to be sown, and the sowing depth is 1 cm. After covering the seed eyes, the sown seedling nutrient block is placed in a seedling tray, and a layer of plastic film is covered on the seedling tray, and the seedling tray is grown at a temperature of 25°C;

[0162] S302, first transplanting:

[0163] Take the field soil and put it into the nutrient pot. When the field plant seedlings grow 1 cm, move the nutrient blocks after emergence into the nutrient pot. Water them after transplanting and place them in an open-air place with sufficient light for growth. Water them once every 2 days.

[0164] S303, Second transplanting:

[0165] After the field plant seedlings have grown in the nutrient pots in S302 for 20 days, the field plant seedlings in the nutrient pots are transplanted into the field with the soil, with a row spacing of 1.2 meters and a plant spacing of 1 meter, leaving 600 seedlings per mu, watering them after transplanting, and growing them into field plants;

[0166] S304, Field Plant Management:

[0167] Timely tillage and weeding;

[0168] S4, attract males:

[0169] In early to mid-June (June 10), at the late stage of vegetative growth of the induced male plants in the flower pots in S203, artificial chemical induced male plants were subjected to induced male plants to obtain induced male plants;

[0170] The method of artificial chemical male induction is: firstly treat the male-induced plants with dark light for 12 hours, then spray the surrounding, top and axillary buds of the male-induced plants with a 1.5mmol / L Ag2S2O3 complex solution for 7 consecutive times, and then spray the 0.3g / L gibberellic acid GA3 solution once after 4 days;

[0171] Starting from the first spraying of the Ag2S2O3 complex solution, the male-inducing plants are kept in a dark light treatment for 12 hours every day until the end of pollination; that is, a dark light treatment for 12 hours and a light treatment for 12 hours every day;

[0172] The spraying interval of the Ag2S2O3 complex solution is once every 4 days;

[0173] The preparation method of the Ag2S2O3 complex solution is as follows: adding distilled water a to AgNO3 and mixing them uniformly to obtain an AgNO3 solution; adding distilled water b to Na2S2O3·5H2O and mixing them uniformly to obtain a Na2S2O3 solution; pouring the AgNO3 solution into the Na2S2O3 solution while stirring, stirring uniformly until no white precipitate appears, to obtain an Ag2S2O3 complex solution;

[0174] The usage ratio of AgNO3, distilled water a, Na2S2O3·5H2O and distilled water b in the Ag2S2O3 complex solution is 2.55g:5L:11g:5L;

[0175] When spraying the pesticide to induce male fertilization, cover the ground where the flower pots are placed with waste newspapers, and dispose of the waste paper separately after the male fertilization is completed. Dispose of the soil in the flower pots separately after the pollination is completed to reduce the pollution of Ag ions to the environment.

[0176] S5. Pollination:

[0177] S501, first field pollination:

[0178] In early August (August 4), the first batch of induced male plants after induced male plants in S4 reached the peak flowering period, the middle and upper flower spikes of the first batch of induced male plants that reached the peak flowering period were cut off, dried at a temperature of 30°C for 36 hours, and the dried flower spikes were crushed and sieved to obtain the first batch of flower spike powder; at this time, the field plants were just in the early flowering stage, and the field plants in S303 at the early flowering stage were pollinated for the first time using an electric artificial pollinator; the unused pollen was stored in a refrigerator at 5°C and taken out for the next pollination;

[0179] S502, Second Field Pollination:

[0180] Cut off the first batch of male-induced plants that have reached the peak flowering period after the middle and upper flower spikes are cut off, and the male-induced plants that have reached the peak flowering period after the first batch of male-induced plants in S4 continue to grow. One week after the first field pollination is completed, the middle and lower flower spikes of the male-induced plants that have reached the peak flowering period after the first batch of male-induced plants in S501 and the middle and upper flower spikes of the male-induced plants that have reached the peak flowering period after the second batch of male-induced plants are cut off, and dried at a temperature of 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain the second batch of flower spike powder; the field plants described in S303 are subjected to a second field pollination using an electric artificial pollinator;

[0181] S503, the third field pollination:

[0182] One week after the second field pollination, the flower spikes of all the induced male plants are cut off, dried at 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain a third batch of flower spike powder; the field plants described in S303 are subjected to a third field pollination using an electric artificial pollinator;

[0183] S6. Harvest:

[0184] In early October (October 9), most of the seeds of the field plants are mature, and the seeds of the field plants are harvested. After harvesting, they are placed in a cool place for a week, then dried and threshed, sorted, packaged and stored. Remember not to mix with other hemp seeds;

[0185] The mass fractions of N, P and K in the nitrogen-phosphorus-potassium compound fertilizers in S1, S203 and S204 are all 15%.

[0186] The average yield per mu of industrial hemp all-female seeds in this embodiment is 40 kilograms.

[0187] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for breeding all-female varieties of industrial hemp, characterized in that: The method is: S1. Site selection: Select an isolated plot of land with no cannabis cultivation within 30 kilometers and apply 40 kg / mu of nitrogen, phosphorus and potassium compound fertilizer; S2. Planting of male-inducing plants: S201. Sowing of male-inducing plants: In early April, industrial hemp seeds with evenly full grains were selected and soaked in clean water for 12 hours to obtain seeds for induced male plants to be sown; Soak the seedling nutrient block with clean water, squeeze out some of the water after the nutrient block is fully absorbed, and obtain the seedling nutrient block to be sown, poke holes in the seedling nutrient block to be sown, sow one seed of the male-inducing plant to be sown in each of the seedling nutrient blocks to be sown, and the sowing depth is 1 cm. After covering the seed eyes, the sown seedling nutrient block is placed in a seedling tray, and a layer of plastic film is covered on the seedling tray, and grown at a temperature of 25°C; the sowing amount of the industrial hemp seeds described in S201 is 30 plants / mu; S202, first transplanting: Take field soil and put it into the nutrient pot. When the male-induced plant seedlings grow 1 cm, move the nutrient blocks after emergence into the nutrient pot. Water the seedlings after transplanting and place them in an open-air place with sufficient light for growth. Water them once every 2 days. S203, Second transplanting: After the male-induced plant seedlings have grown in the nutrient pots described in S202 for 20 days, field soil is placed in the flowerpots and the amount of soil applied is 20 g / 100 kg. 土壤 The male-inducing plant seedlings in the nutrient pots are transplanted into the flower pots together with the soil, watered after transplanting, and placed in an open-air place with sufficient light to grow, thereby obtaining male-inducing plants; S204. Management of male-inducing plants: The spacing between the flower pots after transplanting was 50 cm, and watering was done every 3 days. Every 1 month, 2 g / plant of nitrogen, phosphorus and potassium compound fertilizer was applied while watering. S3. Planting of plants in the field: S301. Sowing of plants in the field: In early to mid-May, select industrial hemp seeds with uniform and full grains and soak them in clean water for 12 hours to obtain seeds for field plants to be sown; Soaking the seedling nutrient blocks with clean water, squeezing out some of the water after the nutrient blocks are fully absorbed, obtaining the seedling nutrient blocks to be sown, poking holes in the seedling nutrient blocks to be sown, sowing one seed of the field plant to be sown in each of the seedling nutrient blocks to be sown, with a sowing depth of 1 cm, and after covering the seed holes, placing the sown seedling nutrient blocks in a seedling tray, and covering the seedling tray with a layer of plastic film, and growing at a temperature of 25° C.; S302, first transplanting: Take the field soil and put it into the nutrient pot. When the field plant seedlings grow 1 cm, move the nutrient blocks after emergence into the nutrient pot. Water them after transplanting and place them in an open-air place with sufficient light for growth. Water them once every 2 days. S303, Second transplanting: After the field plant seedlings have grown in the nutrient pots in S302 for 20 days, the field plant seedlings in the nutrient pots are transplanted into the field with the soil, with a row spacing of 1.2 meters and a plant spacing of 1 meter, leaving 500 to 600 seedlings per mu, and watering them after transplanting to obtain field plants; S304, Field Plant Management: Timely tillage and weeding, no need to water unless there is a severe drought, and timely drainage in case of floods; S4, attract males: In early to mid-June, at the late stage of vegetative growth of the induced male plants described in S203, artificial chemical induced male plants are performed to obtain induced male plants; The method of artificial chemical male induction is: firstly treat the male-induced plants with dark light for 12 hours, then spray the surrounding, top and axillary buds of the male-induced plants with a 1.5mmol / L Ag2S2O3 complex solution for 7 consecutive times, and then spray the 0.3g / L gibberellic acid GA3 solution once after 4 days; Starting from the first spraying of the Ag2S2O3 complex solution, the male-inducing plants are kept in a dark light treatment for 12 hours every day until the pollination is completed; The spraying interval of the Ag2S2O3 complex solution is once every 4 days; The preparation method of the Ag2S2O3 complex solution is as follows: adding distilled water a to AgNO3 and mixing them uniformly to obtain an AgNO3 solution; adding distilled water b to Na2S2O3·5H2O and mixing them uniformly to obtain a Na2S2O3 solution; pouring the AgNO3 solution into the Na2S2O3 solution while stirring and stirring them uniformly to obtain an Ag2S2O3 complex solution; The usage ratio of AgNO3, distilled water a, Na2S2O3·5H2O and distilled water b in the Ag2S2O3 complex solution is 2.55g:5L:11g:5L; S5. Pollination: S501, first field pollination: In early August, the first batch of induced male plants after induced male plants in S4 reaches the peak flowering period, the middle and upper flower spikes of the first batch of induced male plants that reach the peak flowering period are cut off, dried at a temperature of 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain the first batch of flower spike powder; the field plants in S303 at the early flowering stage are pollinated for the first time using an electric artificial pollinator; S502, Second Field Pollination: One week after the first field pollination, the second batch of induced male plants after induced male plants in S4 reached the peak flowering period, the lower and middle flower spikes of the first batch of induced male plants in S501 at the peak flowering period and the upper and middle flower spikes of the second batch of induced male plants at the peak flowering period were cut off, dried at 30° C. for 36 hours, and the dried flower spikes were crushed and sieved to obtain the second batch of flower spike powder; the field plants in S303 were subjected to the second field pollination using an electric artificial pollinator; S503, the third field pollination: One week after the second field pollination, the flower spikes of all the induced male plants are cut off, dried at 30° C. for 36 hours, and the dried flower spikes are crushed and sieved to obtain a third batch of flower spike powder; the field plants described in S303 are subjected to a third field pollination using an electric artificial pollinator; S6. Harvest: In early October, the seeds of the plants in the field are harvested, placed in a cool place for a week, dried, threshed, cleaned, packaged and stored; The mass fractions of N, P and K in the nitrogen-phosphorus-potassium compound fertilizers described in S1, S203 and S204 are all 15%; the water content of the nutrient blocks to be sown and seedling raised described in S201 and S301 is 60% to 70%.

2. The method for breeding all-female varieties of industrial hemp according to claim 1, characterized in that: The specification of the nutrient pot described in S202 is 16cm×16cm; the specification of the flower pot described in S203 is 60cm×60cm.

3. The method for breeding all-female varieties of industrial hemp according to claim 1, characterized in that: The mesh number of the sieving in S501 and S502 is 50 mesh.

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